cerebellar mossy fiber

description: An axon arising from cerebellar projecting cells in the cochlea, vestibular nuclei, spinal cord, reticular formation, cerebellar nuclei and basilar pontine nuclei. Mossy fibers enter through all three cerebellar peduncles and send collaterals to the deep cerebellar nuclei, then branch in the white matter and terminate in the granule cell layer. Through this branching, a given mossy fiber can innervate several folia. Mossy fibers synapse on granule cells. The synaptic contacts are made at enlargements along the length of the mossy fiber called mossy fiber rosettes. The enlargements of the rosettes give the axons a mossy-looking appearance in Golgi stained preparations.


gemmule

category: biolink:CellularComponent biolink:AnatomicalEntity biolink:PhysicalEssence biolink:OrganismalEntity biolink:SubjectOfInvestigation biolink:BiologicalEntity biolink:ThingWithTaxon biolink:NamedThing biolink:PhysicalEssenceOrOccurrent

description: Spine-like process found on some neurons, e.g., periglomerular cells of olfactory cortex.


photoreceptor cell cilium

description: A specialised 9+0 non-motile cilium found in photoreceptor cells. A ciliary transition zone called 'photoreceptor connecting cilium' links the photoreceptor outer segment to the inner segment.


proximal neuron projection

description: The portion of an axon or dendrite that is close to the neuronal cell body.


podocyte primary projection

description: A cell projection originating from a renal glomerular podocyte and extending to the renal glomerular podocyte foot.


rhabdomere microvillus

description: Thin cylindrical membrane-covered projection on the surface of a rhabdomere.


left caudal flagellum

description: A cilium (also called flagellum) found in Giardia species (trophozoite stage). It is nucleated by the left caudal basal body, extending cytoplasmically and exiting at the posterior end of the cell body.


podocyte foot

description: A cell projection of a podocyte (glomerular visceral epithelial cell) forming a foot-like structure projecting from a podocyte primary projection, that wraps around capillaries of a renal glomerulus. Adjacent feet (pedicels) interdigitate, leaving thin filtration slits between them, which are covered by slit diaphragms.


uropod

description: A membrane projection with related cytoskeletal components at the trailing edge of a cell in the process of migrating or being activated, found on the opposite side of the cell from the leading edge or immunological synapse, respectively.


cell hair

description: A long, thin cell projection that contains F-actin and tubulin, with microtubules centrally located and F-actin peripherally located.


longitudinal flagellum

description: A motile cilium found in dinoflagellates. It trails the cell and acts as a steering rudder. It is often partially contained in a furrow called the sulcus, and emerges from a flagellar pore located in the sulcus.


telodendria

description: Telodendria are projections that originate from the axon pedicle and form gap junctions with other neurons.


apical distal dendrite

description: Any dendrite in a dendritic tree that emerges near the apical pole of a neuron, and which is farthest away from the neuronal cell body (the soma).


dentate gyrus mossy fiber

description: Hippocampal mossy fiber produced by dentate gyrus granule cells.


dendritic filopodium

description: A small, membranous protrusion found primarily on dendritic stretches of developing neurons. May receive synaptic input, and can develop into dendritic spines.


basal proximal dendrite

description: Any dendrite in a dendritic tree that emerges near the basal pole of a neuron (e.g. in bipolar neurons, basal dendrites are either on the same side of the soma as the axon, or project toward the axon), and which is the closest to the cell body of the neuron (the soma).


rhabdomere

description: The specialized microvilli-containing organelle on the apical surfaces of a photoreceptor cell containing the visual pigment rhodopsin and most of the proteins involved in phototransduction.


dinoflagellate peduncle

description: A small, flexible, finger-like projection of cytoplasm containing an array of microtubles and located near the flagellar pores in some photosynthetic as well as nonphotosynthetic dinoflagellate species. Its functions are not fully understood, but it has been associated with feeding behavior (phagotrophy).


apical dendrite

description: A dendrite that emerges near the apical pole of a neuron. In bipolar neurons, apical dendrites are located on the opposite side of the soma from the axon.


plastid

description: Any member of a family of organelles found in the cytoplasm of plants and some protists, which are membrane-bounded and contain DNA. Plant plastids develop from a common type, the proplastid.


phenyloplast

description: A chloroplast-derived plastid in which the solid form of phenol is stored.


chloroplast

description: A chlorophyll-containing plastid with thylakoids organized into grana and frets, or stroma thylakoids, and embedded in a stroma.


apicoplast

description: The plastid organelle found in apicomplexans.


etioplast

description: A plastid arrested in the development of chloroplasts from proplastids due to absence of light or low light conditions.


leucoplast

description: A colorless plastid involved in the synthesis of monoterpenes.


chromoplast

description: A plastid containing pigments other than chlorophyll, usually yellow and orange carotenoid pigments.


proteinoplast

description: A leucoplast in which protein is stored.


cyanelle

description: A plastid that contains unstacked, phycobilisome-bearing thylakoid membranes and is surrounded by a double membrane with a peptidoglycan layer in the intermembrane space between the two envelope membranes. Cyanelles are characteristic of algae in the class Glaucophyta, and may represent an ancestral form of plastid.


cell plate

description: The nascent cell membrane and cell wall structure that forms between two daughter nuclei near the center of a dividing plant cell. It develops at the equatorial region of the phragmoplast. It grows outwards to join with the lateral walls and form two daughter cells.


myelin sheath

description: An electrically insulating fatty layer that surrounds the axons of many neurons. It is an outgrowth of glial cells: Schwann cells supply the myelin for peripheral neurons while oligodendrocytes supply it to those of the central nervous system.


egg chorion

description: A protective, noncellular membrane that surrounds the eggs of various animals including insects and fish.


primary lysosome

description: A lysosome before it has fused with a vesicle or vacuole.


ascospore-type prospore nucleus

description: Any nucleus that is part of a ascospore-type prospore.


bacterial-type flagellum filament

description: The long (approximately 20 nm), thin external structure of the bacterial-type flagellum, which acts as a propeller.


dendritic spine origin

description: The part of the dendritic spine neck where the spine arises from the dendritic shaft.


archaeal-type flagellum

description: A non-membrane-bounded organelle superficially similar to a bacterial-type flagellum; they both consist of filaments extending outside the cell, and rotate to propel the cell, but the archaeal flagella (also called archaella) have a unique structure which lacks a central channel. Similar to bacterial type IV pilins, the archaeal flagellins (archaellins) are made with class 3 signal peptides and they are processed by a type IV prepilin peptidase-like enzyme. The archaellins are typically modified by the addition of N-linked glycans which are necessary for proper assembly and/or function.


ventral disc overlap zone

description: A region of the ventral disc of Giardia species (trophozoite stage) where two portions of the same array of microtubules overlap (the microtubule array makes a complete circle and overlaps on itself).


intercellular bridge

description: A direct connection between the cytoplasm of two cells that is formed following the completion of cleavage furrow ingression during cell division. They are usually present only briefly prior to completion of cytokinesis. However, in some cases, such as the bridges between germ cells during their development, they become stabilised.


pollen tube tip

description: The region at growing end of the pollen tube cell, where polarized growth occurs.


microvillus membrane

description: The portion of the plasma membrane surrounding a microvillus.


extrachromosomal rDNA circle

description: Circular DNA molecules encoding ribosomal RNA that are replicated independently of chromosomal replication. These molecules originate in the chromosome but are excised and circularized, often by intramolecular homologous recombination between direct tandem repeats.


axonemal basal plate

description: Part of the axoneme consisting of a highly electron-dense region at the distal end of the ciliary transition zone within the axonemal lumen at which the axonemal central pair of microtubules is connected to the rest of the axonemal structure.


medial membrane band

description: A sterol-rich region of the plasma membrane which forms at the cell surface overlying the contractile ring and spreads into the invaginating plasma membrane surrounding the septum.


vacuolar lumen

description: The volume enclosed within the vacuolar membrane.


somatic portion of tanycyte

description: Portion of a tanycyte that lies within the ependyma and contains the nucleus. A tanycyte is a specialized elongated ventricular ependymal cell that has processes that extend to the outer, or pial, surface of the CNS.


subsynaptic reticulum

description: An elaborate tubulolamellar membrane system that underlies the postsynaptic cell membrane.


plant cell papilla

description: A cell projection that is a short, rounded projection from a plant epidermal cell.


tail portion of tanycyte

description: Elongated process of a tanycyte, devoid of cytoplasmic extensions, that courses through the hypothalamic nuclei to form small endfoot processes that terminate either on blood vessels or at the pial surface of the brain. A tanycyte is a specialized elongated ventricular ependymal cell.


name: axonemal microtubule doublet outer junction

description: The structure which joins the B1 protofilament of the B tubule to the A10 and A11 protofilaments of the A tubule within an axonemal microtubule doublet.


bacterial-type flagellum basal body

description: One of the three major substructures of the bacterial-type flagellum, the basal body is embedded in the cell envelope (the plasma membrane, peptidoglycan cell wall, and, if one is present, the outer membrane); it houses the secretion apparatus that exports the more distal components and the flagellar motor.


yeast-form cell wall

description: The wall surrounding a cell of a dimorphic fungus growing in the single-cell budding yeast form, in contrast to the filamentous or hyphal form.


host cell plasmodesma

description: A fine cytoplasmic channel, found in all higher plants, that connects the cytoplasm of one host cell to that of an adjacent host cell.


manchette

description: A tubular array of microtubules that extends from the perinuclear ring surrounding the spermatid nucleus to the flagellar axoneme. The manchette may also contain F-actin filaments.


contractile actin filament bundle

description: An actin filament bundle in which the filaments are loosely packed (approximately 30-60 nm apart) and arranged with opposing polarities; the loose packing allows myosin (usually myosin-II) to enter the bundle.


extrahaustorial membrane

description: The membrane surrounding the symbiont haustorium during symbiosis, derived from the host plasma membrane.


ectexine

description: The outer part of the exine, which stains positively with basic fuchsin in optical microscopy and has higher electron density in conventionally prepared TEM sections.


periphagosomal region of cytoplasm

description: Cytoplasm situated near, or occurring around, a phagosome.


actin body

description: An amorphous cytoskeletal structure consisting of aggregated actin filaments and associated proteins (including fibrin and capping protein) in which there is little or no actin filament turnover. In yeast (S. pombe and S. cerevisiae) these are found only in quiescent cells and are thought to serve as a reserve store of actin.


karyomere

description: A membrane-bound intermediate cleavage-stage structure of individual or groups of chromosomes that coalesces and fuses with other karyomeres to form a nucleus during interphase. Karyomere formation occurs in blastomeres undergoing rapid cell division.


actin tubule

description: A cellular structure, approximately 13 nm in diameter, consisting of three actin filaments bundled together.


megasporocyte nucleus

description: The nucleus of a megasporocyte, a diploid cell that undergoes meiosis to produce four megaspores, and its descendents.


old cell pole

description: The cell pole distal from the most recent cell division.


sperm fibrous sheath

description: A cytoskeletal structure surrounding the axoneme and outer dense fibers of the sperm flagellum. Consists of two longitudinal columns connected by closely arrayed semicircular ribs that assemble from distal to proximal throughout spermiogenesis. The fibrous sheath probably influences the degree of flexibility, plane of flagellar motion, and the shape of the flagellar beat.


pathogen-containing vacuole membrane

description: Host-derived membrane of a pathogen-containing vacuole.


bacterial-type flagellum hook

description: The portion of the bacterial-type flagellum that connects the filament to the basal body.


new cell pole

description: The cell pole proximal to the most recent cell division.


thylakoid lumen

description: The volume enclosed by a thylakoid membrane.


name: mitotic actomyosin contractile ring, intermediate layer

description: The region of the mitotic actomyosin ring in between the proximal layer and the actin filament layer. This region contains the accessory protein network, some actin filaments and connections between the proximal layer and the actin filament layer.


hemicellulose network

description: Network composed of hemicelluloses; members of a class of plant cell wall polysaccharide that cannot be extracted from the wall by hot water or chelating agents, but can be extracted by aqueous alkali. Includes xylan, glucuronoxylan, arabinoxylan, arabinogalactan II, glucomannan, xyloglucan and galactomannan.


description: A membrane-bounded flattened sac that is formed during micropexophagy between the membrane tips of an engulfing vacuole, completing the engulfment and sequestration of peroxisomes from the cytosol, and forming a micropexophagic body within the lumen of the vacuole.


generative cell nucleus

description: The nucleus of the generative cell, a cell contained within the pollen grain that will divide to produce two haploid sperm cells.


P6 peroxisome

description: A subform of peroxisome that corresponds to an intermediate in a peroxisome assembly pathway, which operates by conversion of peroxisomal subforms in the direction P1, P2 -> P3 -> P4 -> P5 -> P6. P6 peroxisomes are distinguished from the other subforms on the bases of buoyant density and protein content, and are equivalent to mature peroxisomes.


name: microtubule organizing center attachment site

description: A region of the nuclear envelope to which a microtubule organizing center (MTOC) attaches; protein complexes embedded in the nuclear envelope mediate direct or indirect linkages between the microtubule cytoskeleton and the nuclear envelope.


perinuclear endoplasmic reticulum lumen

description: The volume enclosed by the membranes of the perinuclear endoplasmic reticulum.


polyadic synapse

description: A synapse consisting of a single presynapse and multiple postsynapses. These postsynapses may come from the same cell of from different cells. Polyadic synapses are common in arthropod and nematode central nervous systems.


mating projection membrane

description: The portion of the plasma membrane surrounding a mating projection, the projection formed by unicellular fungi in response to mating pheromone.


methane-oxidizing organelle

description: A cytoplasmic, membrane-bounded compartment found within Methanotrophic bacteria that contains enzymes and electron transfer proteins for methane catabolism. This structure is analogous to the thylakoid of Cyanobacteria and the anammoxosome of anaerobic ammonium oxidation organisms.


cleavage apparatus septin structure

description: Any of a series of structures composed of septins and septin-associated proteins localized to the cleavage plane which are involved in cytokinesis.


rod photoreceptor outer segment

description: The outer segment of a vertebrate rod photoreceptor that contains sealed membrane discs that are not connected to the ciliary membrane and containing rhodopsin photoreceptor proteins.


name: lytic vacuole within protein storage vacuole

description: A membrane-bounded compartment containing crystals of phytic acid and proteins characteristic of a lytic vacuole, found within a storage vacuole.


ciliary cap

description: An intracellular compartmentalized cilium structure found in insect spermatids which is bounded by a membrane derived from the invagination of the cell membrane that remains associated with the primary cilium as it is internalized. The ciliary cap is maintained at the end of the axoneme distal to the centriole and is separated from the cytosolic axoneme/cytoplasm by a putative transition zone, which may extend into the ciliary cap, and include a structure at the base of the ciliary cap termed the ring centriole.


host extracellular space

description: The space within a host but external to the plasma membrane of host cells, e.g. within host bloodstream.


female germline ring canal inner rim

description: A proteinaceous actin-rich layer of the insect ovarian ring canal that forms subcortically to the outer rim. The electron dense inner rim accumulates after the final mitotic division of each germline syncytia, and contains actin, a phosphotyrosine protein, and a number of cytoskeletal proteins.


name: cortical layer of collagen and cuticulin-based cuticle extracellular matrix

description: The cuticle layer that lies directly beneath the lipid-containing epicuticle. The cortical layer contains collagens and insoluble, non-collagenous cuticulins and is characterized by a distinct annular pattern consisting of regularly spaced annular ridges delineated by annular furrows. An example of this component is found in Caenorhabditis elegans.


ascospore-type prospore

description: An immature spore undergoing development. The spore usually consists of nucleic acid, prospore membrane(s) that encase the nucleic acid, and ultimately a cell wall that covers the membrane(s). This type of spore is observed in ascospore-forming fungi.


phagocytic cup

description: An invagination of the cell membrane formed by an actin dependent process during phagocytosis. Following internalization it is converted into a phagosome.


male germ cell nucleus

description: The nucleus of a male germ cell, a reproductive cell in males.


exosporium

description: The outermost layer of a bacterial endospore, which is loosely attached and located outside of the endospore coat. It is generally composed of protein, carbohydrate, and perhaps lipid.


mitotic actomyosin contractile ring

description: A cytoskeletal structure composed of actin filaments, myosin, and myosin-associated proteins that forms beneath the plasma membrane of many cells, including animal cells and yeast cells, in a plane perpendicular to the axis of the mitotic spindle, i.e. the cell division plane. Ring contraction is associated with centripetal growth of the membrane that divides the cytoplasm of the two future daughter cells. In animal cells, the mitotic contractile ring is located inside the plasma membrane at the location of the cleavage furrow. In budding fungal cells, e.g. mitotic S. cerevisiae cells, the mitotic contractile ring forms beneath the plasma membrane at the mother-bud neck before mitosis.


multiple synapse bouton

description: A single axon terminal bouton making contact onto two or more dendritic spines protruding either from a single dendrite or from multiple dendrites.


cellular bud membrane

description: The portion of the plasma membrane surrounding a cellular bud.


microbody lumen

description: The volume enclosed by the membranes of a microbody.


extracellular core region of desmosome

description: The desmosomal part containing the desmosomal cadherins, desmogleins and desmocollins, that establish contact and adhere to neighboring cells in a Ca2+-dependent manner.


amyloplast starch grain

description: Plant storage body for amylose and amylopectin, 1-100um in diameter, and located in amyloplasts. Also contains small amounts of enzymes, amino acids, lipids and nucleic acids. The shape of the grain varies widely amongst species, but is often spherical or disk-shaped.


host cell wall

description: The rigid or semi-rigid envelope lying outside the host cell membrane of plant, fungal, and most prokaryotic cells, maintaining their shape and protecting them from osmotic lysis. In plants it is made of cellulose and, often, lignin; in fungi it is composed largely of polysaccharides; in bacteria it is composed of peptidoglycan.


plastid intermembrane space

description: The region between the inner and outer lipid bilayers of the plastid envelope.


mating projection tip membrane

description: The portion of the plasma membrane surrounding a mating projection tip.


name: mitotic spindle pole body attachment site

description: A region of the nuclear envelope to which a spindle pole body (SPB) attaches; protein complexes embedded in the nuclear envelope mediate direct or indirect linkages between the microtubule cytoskeleton and the nuclear envelope.


rhabdomere microvillus membrane

description: The portion of the plasma membrane surrounding a microvillus of a rhabdomere.


spore inner membrane

description: The membrane surrounding the spore core (endospore core) that separates it from its external environment.


cell wall

description: The rigid or semi-rigid envelope lying outside the cell membrane of plant, fungal, most prokaryotic cells and some protozoan parasites, maintaining their shape and protecting them from osmotic lysis. In plants it is made of cellulose and, often, lignin; in fungi it is composed largely of polysaccharides; in bacteria it is composed of peptidoglycan; in protozoan parasites such as Giardia species, it's made of carbohydrates and proteins.


host cellular component

description: Any cellular component of a host cell. The host is an organism in which another organism, for instance a parasite or symbiont, spends part or all of its life cycle and from which it obtains nourishment and/or protection.


mitochondrial inner boundary membrane

description: The portion of the mitochondrial inner membrane that is not invaginated to form cristae. The inner boundary membrane lies parallel to the outer membrane.


macropinocytic cup cytoskeleton

description: The part of the cortical actin cytoskeleton that forms part of a macropinocytic cup.


name: bacterial-type flagellum basal body, MS ring

description: One of the rings of the bacterial-type flagellar basal body; a double-flanged ring that anchors the basal body to the cytoplasmic membrane.


multivesicular body lumen

description: The volume enclosed by the outermost membrane of a multivesicular body.


pilus

description: A proteinaceous hair-like appendage on the surface of bacteria ranging from 2-8 nm in diameter.


pairing center

description: A special chromosome region located towards one end of a chromosome that contains dispersed copies of short, repetitive DNA sequences and functions as a cis-acting element essential for presynaptic homologous chromosome pairing and chromosome-nuclear envelope attachment.


nucleomorph

description: A small, vestigial nucleus found in some plastids that derive from a eukaryotic endosymbiont. Observed in chlorarachniophytes and cryptomonads, which acquired their plastids from a green and red alga respectively.


Gram-positive-bacterium-type cell wall

description: A layer of peptidoglycan found outside of the cytoplasmic membrane. The peptidoglycan is relatively thick (20-80nm) and retains the primary stain of the Gram procedure, thus cells appear blue after Gram stain. The cell walls often contain teichoic acids (acidic anionic polysaccharides) bound to the peptidoglycan. Examples of this component are found in Gram-positive bacteria.


microsporocyte nucleus

description: The nucleus of the microsporocyte. The microsporocyte is a diploid cell in which meiosis will occur, resulting in four microspores. A microspore is a spore that, in vascular plants, gives rise to a male gametophyte.


division septum

description: A cell septum which forms as part of the division site and functions in the compartmentalization of a cell into two daughter cells at division. A division septum spans a cell and does not allow exchange of organelles or cytoplasm between compartments.


ensheathing process

description: A cell projection (often from glial cells such as Schwann cells) that surrounds an unmyelinated axon or cell soma.


proximal portion of axoneme

description: The portion of the axoneme that is close to the base of the cilium.


female germ cell nucleus

description: The nucleus of the female germ cell, a reproductive cell in females.


bacterial outer membrane vesicle

description: A spherical, bilayered proteolipid vesicle released from gram-negative bacterial outer membranes.


type I terminal bouton

description: Terminal inflated portion of the axon of a glutamatergic neuron, containing the specialized apparatus necessary to release neurotransmitters that will induce the contraction of muscle. The axon terminus is considered to be the whole region of thickening and the terminal bouton is a specialized region of it.


fungal-type cell wall

description: A rigid yet dynamic structure surrounding the plasma membrane that affords protection from stresses and contributes to cell morphogenesis, consisting of extensively cross-linked glycoproteins and carbohydrates. The glycoproteins may be modified with N- or O-linked carbohydrates, or glycosylphosphatidylinositol (GPI) anchors; the polysaccharides are primarily branched glucans, including beta-linked and alpha-linked glucans, and may also include chitin and other carbohydrate polymers, but not cellulose or pectin. Enzymes involved in cell wall biosynthesis are also found in the cell wall. Note that some forms of fungi develop a capsule outside of the cell wall under certain circumstances; this is considered a separate structure.


photoreceptor connecting cilium

description: The portion of the photoreceptor cell cilium linking the photoreceptor inner and outer segments. It's considered to be equivalent to the ciliary transition zone.


nuclear matrix

description: The dense fibrillar network lying on the inner side of the nuclear membrane.


name: multiple synapse bouton, contacting multiple dendrites

description: A single axon terminal bouton making contact onto two or more dendritic spines protruding from multiple dendrites.


host cell membrane pore complex

description: Any small opening in a host cell membrane that allows the passage of gases and/or liquids, composed of host proteins.


migrasome

description: A vesicular organelle that forms on retraction fibers behind migrating cells and mediates the release of cytoplasmic contents during cell migration.


mitotic nuclear bridge midzone

description: The central region of a mitotic nuclear bridge, distal to the main portions of the daughter nuclei.


pellicular membrane

description: The portion of the plasma membrane surrounding the pellicle, a structure enclosing some parasite cells such as certain apicomplexa and Euglenozoa. These membranes are associated with an infrastructure of microtubules, microfilaments, and other organelles.


myofilament

description: Any of the smallest contractile units of a myofibril (striated muscle fiber).


leading edge of lamellipodium

description: That part of the lamellipodium which represents the distal part of the structure.


polytene chromosome ectopic fiber

description: A thread-like connection joining two regions of ectopically paired polytene chromosomes.


photoreceptor distal connecting cilium

description: The distal region of the photoreceptor connecting cilium is structurally unique to the photoreceptor and is maintained by retina-specific protein, SPATA7, and its interacting partners RPGR and RPGRIP1. It is essential for photoreceptor sensory cilium stability.


ficolin-1-rich granule lumen

description: Any membrane-enclosed lumen that is part of a ficolin-1-rich granule.


tertiary granule lumen

description: Any membrane-enclosed lumen that is part of a tertiary granule.


right ventral basal body

description: Any ciliary basal body that is part of a right ventral flagellum found in Giardia species (trophozoite stage).


microneme membrane

description: The lipid bilayer surrounding a microneme.


phragmoplast

description: The phragmoplast is a plant cell specific cytoplasmic structure composed of cytoskeletal polymers, membranes, and associated cytosolic proteins that functions as the focused secretory module for assembling the cell plate.


new growing cell tip

description: A cell tip that was newly formed at the last cell division, and that has started to grow after the cell has activated bipolar cell growth (i.e. in which new end take-off, NETO, has taken place). New end take-off is when monopolar cells initiate bipolar growth.


chloroplast inner membrane

description: The inner, i.e. lumen-facing, lipid bilayer of the chloroplast envelope; also faces the chloroplast stroma.


apical cytoplasm

description: The region of the cytoplasm located at the apical side of the cell. Used in reference to animal polarized epithelial cells.


ventral surface of cell

description: The surface of a migrating cell that is in contact with the substratum or cell layer.


glycocalyx

description: A carbohydrate rich layer at the outermost periphery of a cell.


keratohyalin granule

description: A cytoplasmic, non-membrane bound granule of, at least, keratinocyte. Associated to keratin intermediate filaments and partially crosslinked to the cell envelope.


micronucleus

description: A membrane-bounded organelle of ciliated protozoan cells that contains a diploid copy of the cell's complete genome. Sections of contiguous sequence in the macronucleus are often interrupted by internal eliminated sequences (IES), and may be permuted, in micronuclei. Genic transcription is not found in micronuclei. Some ciliate species may contain multiple micronuclei per cell.


name: bacterial-type flagellum basal body, proximal rod

description: The portion of the central rod of the bacterial-type flagellar basal body that is proximal to the cell membrane; the proximal rod connects the distal rod to the flagellar motor.


plant-type cell wall

description: A more or less rigid structure lying outside the cell membrane of a cell and composed of cellulose and pectin and other organic and inorganic substances.


chrorion micropyle

description: A single cone-shaped specialization that forms an opening in the egg chorion that allows sperm entry into the egg prior to fertilization.


pirellulosome

description: A cytoplasmic structure found in bacterial phyla Planctomycetes and Verrucomicrobia containing a condensed nucleoid and ribosomes and surrounded by an intracytoplasmic membrane. It is surrounded by ribosome-free cytoplasm, in a compartment called the paryphoplasm.


dinoflagellate antapex

description: The anterior most point of a dinoflagellate hypocone.


terminal cisterna lumen

description: The region between the inner and outer lipid bilayers of the terminal cisterna envelope. This space is enriched in calsequestrin.


stereocilium tip

description: A distinct compartment at the tip of a stereocilium, distal to the site of attachment to the apical cell surface. It consists of a dense matrix bridging the barbed ends of the stereocilium actin filaments with the overlying plasma membrane, is dynamic compared to the shaft, and is required for stereocilium elongation.


glycosome

description: A membrane-bounded organelle found in organisms from the order Kinetoplastida that houses the enzymes of glycolysis.


plasmodesmatal cytoplasmic sleeve

description: The space between the plasma membrane and the desmotubule of a plasmodesma.


concave side of sperm head

description: The concave part of the late spermatid head or spermatozoon head that forms the ventral portion of the head, particularly in some rodent species.


microsporidian-type endospore

description: The middle layer in a microsporidian spore wall that lies under the exospore and outside the plasma membrane, containing chitin and proteins.


actin wave

description: A cellular anatomical entity that is part of the actin cytoskeleton and results in a wave-like propagation of actin networks. It consists of dynamic structures traveling on the ventral (substrate-attached) side of the cell during cell migration, cytokinesis, adhesion and neurogenesis.


epididymosome

description: A microvesicle of the epididymal fluid, from which spermatozoa acquire membrane proteins.


perinucleolar compartment

description: The perinucleolar compartment (PNC) is a subnuclear structure associated with, but structurally distinct from, the nucleolus. The PNC contains large amounts of the heterogeneous nuclear ribonucleoprotein complex (hnRNP) called hnRNP 1 (PTB). Many RNA binding proteins as well as RNA polymerase III transcripts are highly enriched in this compartment. PTB and pol III transcripts are required for the integrity of the PNC.


type II terminal bouton

description: Terminal inflated portion of the axon of a non-glutamatergic neuron, containing the specialized apparatus necessary to release neurotransmitters at a regulatory synapse. The axon terminus is considered to be the whole region of thickening and the terminal bouton is a specialized region of it.


periarbuscular membrane

description: A host-derived membrane surrounding the symbiont arbuscule during symbiosis.


dinoflagellate apex

description: The anterior most point of a dinoflagellate epicone.


symbiont-containing vacuole membrane

description: The lipid bilayer surrounding a symbiont-containing vacuole, derived from both the host and symbiont.


ciliary microtubule quartet

description: A set of four specialized microtubules that originates from the basal bodies and wraps around the ciliary pocket membrane, likely supporting its distinct flask shape.


name: symmetric, GABA-ergic, inhibitory synapse

description: A neuron to neuron synapse that lacks an electron dense postsynaptic specialization, uses GABA as a neurotransmitter and whose activity results in inhibitory postsynaptic potentials.


scintillon

description: A body present in the cytoplasm of some dinoflagellates, which is the source of bioluminescence; emits light on acidification in the presence of oxygen.


cell pole

description: Either of two different areas at opposite ends of an axis of a cell.


P3 peroxisome

description: A subform of peroxisome that corresponds to an intermediate in a peroxisome assembly pathway, which operates by conversion of peroxisomal subforms in the direction P1, P2 -> P3 -> P4 -> P5 -> P6. P3 peroxisomes are formed by fusion of P1 and P2 peroxisomes, and are distinguished from the other subforms on the bases of buoyant density and protein content.


name: surface coat of collagen and cuticulin-based cuticle extracellular matrix

description: An electron dense, amorphous envelope that comprises the outermost layer of the cuticle. The surface coat is loosely apposed to the epicuticle, has distinct biochemical properties, is synthesized by cells other than the underlying hypodermis, and is labile. In addition to serving as a lubricant to protect against abrasion and dehydration, the surface coat may also play important roles in infection and immune evasion. An example of this component is found in Caenorhabditis elegans.


name: nuclear envelope adjacent to nuclear pore complex

description: The region of the nuclear envelope situated in close proximity to a nuclear pore complex.


rod photoreceptor disc lumen

description: The volume enclosed by the membrane of a rod photoreceptor cell disc membrane.


leaflet of membrane bilayer

description: Any of the two layers of lipid molecules that constitute a membrane.


distal portion of axoneme

description: The portion of the axoneme that is close to the tip of the cilium.


sperm mitochondrial sheath

description: The tightly packed helical sheath of ATP-producing mitochondria restricted to the midpiece of the sperm flagellum.


host cell endomembrane system

description: A collection of membranous structures involved in transport within the host cell. The main components of the endomembrane system are endoplasmic reticulum, Golgi bodies, vesicles, cell membrane and nuclear envelope. Members of the endomembrane system pass materials through each other or though the use of vesicles. The host is defined as the larger of the organisms involved in a symbiotic interaction.


mucus layer

description: An extracellular region part that consists of a protective layer of mucus secreted by epithelial cells lining tubular organs of the body such as the colon or secreted into fluids such as saliva. Mucus is a viscous slimy secretion consisting of mucins (i.e. highly glycosylated mucin proteins) and various inorganic salts dissolved in water, with suspended epithelial cells and leukocytes.


name: extrinsic component of periplasmic side of cell outer membrane

description: The component of the cell outer membrane consisting of gene products and protein complexes that are loosely bound to periplasmic surface, but not integrated into the hydrophobic region.


nucleus leading edge

description: The area of a motile nucleus closest to the direction of movement.


dendritic knob

description: The terminal swelling of an apical dendrite of a ciliated olfactory receptor neuron. Each knob gives rise to 5 to 20 long delicate nonmotile cilia, which extend into the mucus covering the sensory epithelium.


pronucleus

description: The nucleus of either the ovum or the spermatozoon following fertilization. Thus, in the fertilized ovum, there are two pronuclei, one originating from the ovum, the other from the spermatozoon that brought about fertilization; they approach each other, but do not fuse until just before the first cleavage, when each pronucleus loses its membrane to release its contents.


chloroplast stroma

description: The space enclosed by the double membrane of a chloroplast but excluding the thylakoid space. It contains DNA, ribosomes and some temporary products of photosynthesis.


rough endoplasmic reticulum lumen

description: The volume enclosed by the membranes of the rough endoplasmic reticulum.


perforation plate

description: A cell wall part that is the part of a wall of a vessel member and bears one or more openings (perforations).


pathogen-containing vacuole lumen

description: The enclosed volume within the sealed membrane of a pathogen-containing vacuole.


sperm glycocalyx

description: The carbohydrate rich layer at the outermost periphery of a sperm cell.


cuticular plate

description: A dense network of actin filaments found beneath the apical cell surface of hair cells, and into which stereocilia are inserted.


type I pilus

description: A short filamentous structure on the surface of a bacterial cell distinguished from other pili by their D-mannose-sensitive agglutinatination of erythrocytes. In E. coli, type I pili consist of a short tip fibrillum made up of the adhesin protein (FimH) and two minor subunits (FimG and FimF) that is joined to the pilus rod, a homopolymer of ~1000 FimA subunits.


amyloplast membrane

description: Either of the lipid bilayers that surround an amyloplast and form the amyloplast envelope.


polytene chromosome weak point

description: A region of the polytene chromosome where the diameter is considerably decreased, probably resulting from local differences in chromosome organization.


cyanelle stroma

description: The space enclosed by the double membrane of a cyanelle.


neuron projection branch point

description: The location where a secondary projection arises from a neuron projection.


chloroplast membrane

description: Either of the lipid bilayers that surround a chloroplast and form the chloroplast envelope.


cell body membrane

description: The plasma membrane of a cell that bears surface projections such as axons, dendrites, cilia, or flagella, excluding the plasma membrane on cell projections.


proplastid stroma

description: The space enclosed by the double membrane of a proplastid.


ciliary shaft

description: The mid part of a cilium between the ciliary base and ciliary tip that extends into the extracellular space.


intracellular immature spore

description: A cell or part of the cell that constitutes an early developmental stage of a spore, a small reproductive body that is highly resistant to desiccation and heat and is capable of growing into a new organism, produced especially by certain bacteria, fungi, algae, and nonflowering plants.


male pronucleus

description: The pronucleus originating from the spermatozoa that was involved in fertilization.


rhoptry

description: A large, club-shaped secretory organelle that forms part of the apical complex of an apicomplexan parasite, and consists of a bulbous body and a narrow electron-dense neck that extends through the conoid at the apical tip of the parasite. The rhoptry necks serve as ducts through which the contents of the rhoptries are secreted after attachment to the host has been completed and at the commencement of invasion. Rhoptry proteins function in the biogenesis and host organellar association of the parasitophorous vacuole.


cortical endoplasmic reticulum lumen

description: The volume enclosed by the membranes of the cortical endoplasmic reticulum.


striated muscle thin filament

description: Filaments formed of actin and associated proteins; attached to Z discs at either end of sarcomeres in myofibrils.


gerontoplast stroma

description: Any plastid stroma that is part of a gerontoplast.


spindle pole body

description: The microtubule organizing center in fungi; functionally homologous to the animal cell centrosome.


axon initial segment

description: Portion of the axon proximal to the neuronal cell body, at the level of the axon hillock. The action potentials that propagate along the axon are generated at the level of this initial segment.


pilus tip

description: The pointed extremity furthest from the cell of a pilus.


meiotic spindle pole

description: Either of the ends of a meiotic spindle, a spindle that forms as part of meiosis, where spindle microtubules are organized; usually contains a microtubule organizing center and accessory molecules, spindle microtubules and astral microtubules.


subpellicular network

description: A mechanically stable cytoskeletal structure associated with the cytoplasmic face of the pellicle and surrounding the microtubule-based cytoskeleton.


hydrogenosome lumen

description: The volume enclosed by the hydrogenosome membrane.


recombination nodule

description: An electron dense structure that is associated with meiotic chromosomes.


intermediate layer of spindle pole body

description: Structure between the central and outer plaques of the spindle pole body.


primary cell wall

description: A plant cell wall that is still able to expand, permitting cell growth. Primary cell walls contain more pectin than secondary walls and no lignin is present.


inner mucus layer

description: The inner of two mucus layers secreted by epithelial cells in the colon; the inner mucus layer is firmly attached to the epithelium, is densely packed with a compact stratified appearance and is devoid of bacteria.


S-layer

description: A crystalline protein layer surrounding some bacteria.


kinociliary basal body

description: A ciliary basal body that is part of a kinocilium.


pericellular basket

description: Ramification of basket cell axon surrounding cell bodies, forming the characteristic pericellular baskets from which the cell class derives its name.


half bridge of spindle pole body

description: Structure adjacent to the plaques of the spindle pole body.


glycoprotein network

description: An extracellular matrix part that consists of cross-linked glycoproteins.


acidocalcisome

description: An electron-dense acidic membrane-bounded organelle which contains a matrix of pyrophosphate and polyphosphates with bound calcium and other cations.


endoplasmic reticulum cisternal network

description: A subcompartment of the endoplasmic reticulum consisting of flattened, disc-shaped domains known as cisternae. These are typically found close to the nucleus and are generally more prominent in secretory cells.


podosome ring

description: The ring structure surrounding the podosome core, containing proteins such as vinculin and talin.


host cell junction

description: A plasma membrane part that forms a specialized region of connection between two host cells or between a host cell and the host extracellular matrix. At a host cell junction, anchoring proteins extend through the host plasma membrane to link cytoskeletal proteins in one cell to cytoskeletal proteins in neighboring cells or to proteins in the extracellular matrix.


outer plaque of spindle pole body

description: One of three laminate structures that form the spindle pole body; the outer plaque is in the cytoplasm.


mitotic spindle midzone

description: The area in the center of the anaphase spindle consisting of microtubules, microtubule bundling factors and kinesin motors where the spindle microtubules from opposite poles overlap in an antiparallel manner.


mossy fiber rosette

description: A synapse of a mossy fiber onto the dendrite of a granule cell; each mossy fiber can have up to 50 rosettes.


plastid membrane

description: Either of the lipid bilayers that surround a plastid and form the plastid envelope.


host cell late endosome membrane

description: The lipid bilayer surrounding a host cell late endosome.


chloroplast starch grain

description: Plant storage body for amylose and amylopectin, 1-100um in diameter, and located in chloroplasts. Also contains small amounts of enzymes, amino acids, lipids and nucleic acids. The shape of the grain varies widely amongst species, but is often spherical or disk-shaped.


endexine

description: The inner part of the exine, which stains.


name: endoplasmic reticulum tubular network membrane

description: The membrane of the endoplasmic reticulum tubular network.


acroblast

description: A cone-shaped structure in the head of a spermatozoon, which is formed by the coalescence of Golgi fragments following the completion of meiosis. The acroblast is situated adjacent to the acrosomal vesicle.


haustorium

description: A projection from a cell or tissue that penetrates the host's cell wall and invaginates the host cell membrane.


autolysosome lumen

description: The volume that is enclosed within the autolysosome single-membrane.


dendrite terminus

description: A structure at the distal end of a dendrite adapted to carry out a specific function, e.g. dendriole.


name: inner plaque of mitotic spindle pole body

description: One of three laminate structures that form the mitotic spindle pole body; the inner plaque is in the nucleus.


extraorganismal space

description: The environmental space outside of an organism; this may be a host organism in the case of parasitic and symbiotic organisms.


basal body patch

description: The region in the apical portion of multiciliated epithelial cells where the ciliary basal bodies cluster.


cofilin-actin rod

description: A cellular structure consisting of parallel, hexagonally arranged actin tubules, comprising filamentous actin and disulfide cross-linked cofilin multimers.


pectic matrix

description: The gel-like pectin matrix consists of the interlinked acidic and neutral pectin networks that are further cross-linked by calcium bridges. Pectins consist largely of long chains of mostly galacturonic acid units (typically 1,4 linkages and sometimes methyl esters). Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan I and rhamnogalacturonan II) are thought to occur in all primary cell walls.


acidocalcisome membrane

description: The lipid bilayer surrounding an acidocalcisome.


photoreceptor inner segment membrane

description: The membrane surrounding the inner segment of a vertebrate photoreceptor. The photoreceptor inner segment contains mitochondria, ribosomes and membranes where opsin molecules are assembled and passed to be part of the outer segment discs.


name: organellar chromatophore intermembrane space

description: The region between the inner and outer lipid bilayers that surround an organellar chromatophore.


type Is terminal bouton

description: Terminal inflated portion of the axon of a glutamatergic neuron, containing the specialized apparatus necessary for the phasic release neurotransmitters that will induce the contraction of muscle. Type Is terminal boutons are smaller than type Ib terminal boutons.


plasmodesmatal plasma membrane

description: The portion of the plasma membrane surrounding a plasmodesma.


basal labyrinth

description: A region in the lower half of some cells formed from extensive infoldings of the basal plasma membrane; includes cytoplasm adjacent to the infolded membrane.


axonemal central pair projection

description: Part of the 9+2 axoneme, that occurs in most motile cilia, consisting of the projections off of the central pair of single microtubules.


mesaxon

description: Portion of the ensheathing process (either myelin or non-myelin) where the enveloping lips of the ensheathing cell come together so that their apposed plasma membranes run parallel to each other, separated by a cleft 12 nm wide.


filopodium tip

description: The end of a filopodium distal to the body of the cell.


name: basal layer of collagen and cuticulin-based cuticle extracellular matrix

description: The layer of cuticle most closely apposed to the hypodermal cells. The morphology of the basal layer varies with life stage. In adult C. elegans animals, the basal layers is comprised of three sublayers: two fibrous layers whose fibers run in clockwise and counter-clockwise directions meeting one another at a 60 degree angle, and an amorphous basal layer that lies underneath the fibrous layers and directly contacts the hypodermis. In C. elegans dauer and L1 larval stage animals, the basal layer is characterized by a striated pattern that appears to derive from interwoven laminae. An example of this component is found in Caenorhabditis elegans.


macronucleus

description: A membrane-bounded organelle of ciliated protozoan cells that contains polyploid copies of a portion of the cell's complete genome. Transcription of genes occurs in macronuclei. Some ciliate species may contain multiple macronuclei per cell.


cleavage furrow

description: The cleavage furrow is a plasma membrane invagination at the cell division site. The cleavage furrow begins as a shallow groove and eventually deepens to divide the cytoplasm.


ventral disc crossbridge

description: Structure horizontally linking adjacent microribbons of the ventral disc in Giardia species (trophozoite stage). The composition of crossbridges is not fully known yet.


postsynaptic endocytic zone

description: A stably positioned site of clathrin adjacent and physically attached to the postsynaptic specialization, which is the site of endocytosis of post-synaptic proteins.


name: host cell rough endoplasmic reticulum membrane

description: The lipid bilayer surrounding the host cell rough endoplasmic reticulum.


host cell endosome membrane

description: The lipid bilayer surrounding a host cell endosome.


cyanelle intermembrane space

description: The region between the inner and outer lipid bilayers of the cyanelle envelope; includes the peptidoglycan layer.


longitudinal side of cell surface

description: The side of the cell parallel to the zygotic axis.


metaphase plate

description: The intracellular plane, located halfway between the poles of the spindle, where chromosomes align during metaphase of mitotic or meiotic nuclear division.


tectum

description: The layer of sexine which forms a roof over the columella, granules or other infratectal elements.


type IV pilus

description: A short filamentous structure on the surface of a bacterial cell distinguished from other pili by post-translational N-methylation of the pilin monomers.


lysosomal glycocalyx

description: The polysaccharide-based coating on the inner side of a lysosomal membrane. It may be involved in protecting the membrane from digestion by lysosomal enzymes.


fusome

description: A large intracellular spectrin-rich structure that has been found in insect germline cells and mammalian hematopoietic cells. The fusome is an elongated, branched structure, formed from the spherical spectrosome organelle.


periplasmic space

description: The region between the inner (cytoplasmic) and outer membrane (Gram-negative Bacteria) or cytoplasmic membrane and cell wall (Fungi and Gram-positive Bacteria).


left tetrad

description: Set of four basal bodies found in Giardia species (trophozoite stage). It comprises the left lateral basal body pair and the left middle basal body pair (i.e. the anterior, ventral, caudal and posteriolateral basal bodies located to the right of the left nucleus of the trophozoite when viewed dorsally).


cyanelle membrane

description: Either of the lipid bilayers that surround a cyanelle and form the cyanelle envelope.


striated muscle dense body

description: A vinculin-containing myofibril attachment structure of striated muscle that connects sarcomeres to the extracellular matrix. In nematode body wall muscle, the dense body performs the dual role of Z-disk and costamere.


bacterial-type flagellum motor

description: A transmembrane complex embedded in the cytoplasmic membrane which is the motor force, or torque, generator of the bacterial-type flagellum. The motor consists of a membrane-anchored rotor complex surrounded by one or more stator complexes in the cytoplasmic membrane. The stator consists of a hetero-hexameric complex of 2 membrane proteins, A and B, with stoichiometry A4B2. Examples are the H+ driven MotA-MotB stator complex of Escherichia coli and Salmonella enterica, and the Na+ driven PomA-PomB stator complex of Vibrio and Shewanella species. The rotor complex consists of a membrane-anchored ring and the motor switch complex, which controls the direction of flagellar rotation.


omegasome

description: Omega-shaped (as in the Greek capital letter) intracellular membrane-bounded organelle enriched in phosphatidylinositol 3-phosphate and dynamically connected to the endoplasmic reticulum. Omegasomes are the first step of the formation of autophagosomes via the phagophore assembly sites.


extrachromosomal DNA

description: DNA structures that are not part of a chromosome.


name: axonemal microtubule doublet inner sheath

description: A structural network of microtubule inner proteins (MIPs) located inside the lumens of the A and B tubules of the axonemal microtuble doublet that helps stabilize the doublet microtubule.


host cell postsynaptic membrane

description: A postsynaptic membrane that is part of a host cell. A postsynaptic membrane is a specialized area of membrane facing the presynaptic membrane on the tip of the nerve ending and separated from it by a minute cleft (the synaptic cleft). Neurotransmitters transmit the signal across the synaptic cleft to the postsynaptic membrane.


mating projection tip

description: The apex of the mating projection in unicellular fungi exposed to mating pheromone; site of polarized growth.


spindle envelope

description: An organelle envelope that surrounds the chromosomes and the central part of the spindle apparatus during mitosis and meiosis; observed in many invertebrates. The spindle envelope consists of membrane layers, called parafusorial membranes, derived from endoplasmic reticulum membrane; in male meiosis it forms during prometaphase and persists until early in the ensuing interphase.


hyaluranon cable

description: A cable structure, surrounding some cell types (e.g. proximal or bronchial tubular epithelial cells), and composed of hyaluranon (HA), a ubiquitous connective tissue glycosaminoglycan.


non-growing cell tip

description: A cell tip at which no growth takes place. For example, in fission yeast the cell end newly formed by cell division does not grow immediately upon its formation, and lacks actin cytoskeletal structures.


periciliary membrane compartment

description: A plasma membrane region adjacent to the base of eukaryotic cilia and flagella that is enriched in endocytosis-associated proteins and vesicles and that appears to regulate ciliary membrane homeostasis.


starch grain

description: Plant storage body for amylose and amylopectin, 1-100um in diameter. Also contains small amounts of enzymes, amino acids, lipids and nucleic acids. The shape of the grain varies widely amongst species, but is often spherical or disk-shaped.


name: host cell smooth endoplasmic reticulum membrane

description: The lipid bilayer surrounding the host cell smooth endoplasmic reticulum.


name: photoreceptor proximal connecting cilium

description: The proximal region of the photoreceptor connecting cilium is similar to the transition zone of unspecialized primary cilia and houses several major transition zone complexes, including NPHP, MKS, and RPGR.


name: perforant pathway to dendrate granule cell synapse

description: A neuron to neuron synapse of a pyramidal neuron in the entorhinal cortex onto a granule cell in the dentate gyrus of the hippocampus.


axolemma

description: The portion of the plasma membrane surrounding an axon; it is a specialized trilaminar random mosaic of protein molecules floating within a fluid matrix of highly mobile phospholipid molecules, 7-8 nm in thickness.


Woronin body

description: Peroxisome-derived dense-core vesicle that seals septal pores upon hyphal lysis to prevent excessive cytoplasmic loss. It is specific to several genera of filamentous ascomycetes.


meiotic spindle pole body

description: The microtubule organizing center that forms as part of the meiotic cell cycle; functionally homologous to the animal cell centrosome.


muscle cell projection membrane

description: The portion of the plasma membrane surrounding a muscle cell projection.


Isp3 layer of spore wall

description: The outermost layers of the spore wall, as described in Schizosaccharomyces pombe.


granular component

description: A structure found in the nucleolus, which contains nearly completed preribosomal particles destined for the cytoplasm.


spine mat

description: A configuration of neuron spines found on ciliary ganglion neurons in the embryonic and adult brain consisting of patches of closely spaced spines lying flat against the soma.


DIM/DIP cell wall layer

description: A section of the Actinobacterium-type cell wall composed of (phenyl)phthiocerol, phthiodiolone, phthiotriol dimycocerosate, diphthioceranate and other compounds.


microvesicle

description: An extracellular vesicle released from the plasma membrane and ranging in size from about 100 nm to 1000 nm.


ciliary pro-basal body

description: The cilary pro-basal body is an immature, partially assembled form of a ciliary basal body found next to the basal body of a cilium. Pro-basal bodies are not capable of nucleating a cilium. As the cell progresses through the cell cycle, continuing assembly will convert the pro-basal body into a mature basal body that is capable of nucleating a cilium.


ciliary inversin compartment

description: Proximal part of the ciliary shaft to which the inversin protein (also called Inv) specifically localizes. The inversin compartment appears to have a different protein composition than the rest of the cilium, although there is no structure that separates it form the distal part of the cilium.


plastid stroma

description: The proteinaceous ground substance of plastids.


rhoptry lumen

description: The volume enclosed by the rhoptry membrane.


left posteriolateral basal body

description: Any ciliary basal body that is part of a left posteriolateral flagellum found in Giardia species (trophozoite stage).


dendriole

description: Small dendrites that makes up a brush structure found as the terminal specialization of a dendrite of a unipolar brush cell (UBC).


host cell

description: A cell within a host organism. Includes the host plasma membrane and any external encapsulating structures such as the host cell wall and cell envelope.


plasma membrane of growing cell tip

description: Any plasma membrane part that is part of a growing cell tip.


spongiome

description: A cellular anatomical entity which is a network of tubules and vessicles and is part of the contractile vacuole complex. It is involved in the discharge of water externally. One of its functions is osmoregulatory.


Golgi stack lumen

description: The volume enclosed by any of the membranes of the thin, flattened cisternae that form the central portion of the Golgi complex.


antipodal cell nucleus

description: The nucleus of an antipodal cell, one of three cells of the embryo sac in angiosperms, found at the chalazal end of the embryo away from the point of entry of the pollen tube, and its descendents.


sperm midpiece

description: The highly organized segment of the sperm flagellum which begins at the connecting piece and is characterized by the presence of 9 outer dense fibers (ODFs) that lie outside each of the 9 outer axonemal microtubule doublets and by a sheath of mitochondria that encloses the ODFs and the axoneme; the midpiece terminates about one-fourth of the way down the sperm flagellum at the annulus, which marks the beginning of the principal piece.


costamere

description: Regular periodic sub membranous arrays of vinculin in skeletal and cardiac muscle cells, these arrays link Z-discs to the sarcolemma and are associated with links to extracellular matrix.


glycogen granule

description: Cytoplasmic bead-like structures of animal cells, visible by electron microscope. Each granule is a functional unit with the biosynthesis and catabolism of glycogen being catalyzed by enzymes bound to the granule surface.


pollen wall

description: The wall surrounding a mature pollen grain; a multilayered structure consisting of a pectocellulosic intine surrounded by a sporopollenin-based exine, which itself contains two layers, the inner nexine and the outer sexine.


host cell part

description: Any constituent part of a host cell. The host is defined as the larger of the organisms involved in a symbiotic interaction.


cellular bud tip

description: The end of a cellular bud distal to the site of attachment to the mother cell.


slime layer

description: A slime layer is an easily removed, diffuse, unorganized layer of extracellular material that surrounds a cell. Specifically this consists mostly of exopolysaccharides, glycoproteins, and glycolipids.


DNA replication termination region

description: A chromosomal region that contains fork pausing elements influencing the progression and merging of DNA replication forks.


sperm head-tail coupling apparatus

description: A centrosome-based structure consisting of two cylindrical microtubule-based centrioles and associated components which anchors the flagellum to the sperm head.


host cell envelope

description: An envelope that surrounds a bacterial host cell and includes the host cytoplasmic membrane and everything external, encompassing the host periplasmic space, host cell wall, and host outer membrane if present.


satellite fibril

description: An axoneme part that is found in the flagella of mammalian sperm and is located in the middle piece between the outer dense fibers (on the concave side of outer dense fibers as seen in cross-section).


chitosan layer of spore wall

description: The second outermost layer of the spore wall, as described in Saccharomyces.


presynaptic grid

description: A hexagonal array of electron dense particles attached to the cytoplasmic face of the presynaptic membrane.


sperm head plasma membrane

description: The plasma membrane that is part of the head section of a sperm cell.


ciliary pocket collar

description: A constriction site at the junction of the plasma, flagellar and flagellar pocket membranes where the flagellum emerges from the cell body. Observed in some unicellular eukaryotic species such as Chlamydomonas, Giardia and Trypanosoma.


rod bipolar cell terminal bouton

description: A specialized region of the axon terminus portion of a rod bipolar axon. A rod bipolar cell is a neuron found in the retina and having connections with rod photoreceptor cells and neurons in the inner plexiform layer.


vascular endothelial glycocalyx

description: The carbohydrate-rich layer lining the vascular endothelium connected to the endothelium through a variety of molecules, mainly proteoglycans and glycoproteins. These form a network in which soluble molecules, either plasma- or endothelium-derived, are incorporated.


host cell membrane

description: Double layer of lipid molecules as it encloses host cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins. The host is defined as the larger of the organisms involved in a symbiotic interaction.


immunological synapse

description: An area of close contact between a lymphocyte (T-, B-, or natural killer cell) and a target cell formed through the clustering of particular signaling and adhesion molecules and their associated membrane rafts on both the lymphocyte and the target cell and facilitating activation of the lymphocyte, transfer of membrane from the target cell to the lymphocyte, and in some situations killing of the target cell through release of secretory granules and/or death-pathway ligand-receptor interaction.


capsule

description: A protective structure surrounding some fungi and bacteria, attached externally to the cell wall and composed primarily of polysaccharides. Capsules are highly organized structures that adhere strongly to cells and cannot be easily removed. Capsules play important roles in pathogenicity, preventing phagocytosis by other cells, adherence, and resistance to desiccation.


name: bacterial-type flagellum hook-filament junction

description: The region of the bacterial-type flagellum where the hook and filament meet.


female pronucleus

description: The pronucleus originating from the ovum that is being fertilized.


C bouton

description: Synaptic bouton found in spinal cord on the soma and proximal dendrites of motor neurons.


plastid thylakoid lumen

description: The volume enclosed by a plastid thylakoid membrane.


sporoplasm

description: The complex infective apparatus corresponding to the central mass of cytoplasm within a spore that is injected into a host cell by various parasitic microorganisms.


cone matrix sheath

description: A biochemically and structurally distinct domain of the retinal interphotoreceptor matrix that is specifically associated with cone photoreceptor cell inner and outer segments.


nexine

description: The inner, non-sculptured part of the exine which lies below the sexine.


ring centriole

description: A ring-like structure observed at the base of the ciliary cap of insect spermatids. This structure may anchor the axoneme to the ciliary cap membrane and/or act as a diffusion barrier, proposed to be analogous to the annulus of mammalian sperm flagellum.


meiotic actomyosin contractile ring

description: A cytoskeletal structure composed of actin filaments, myosin, and myosin-associated proteins that forms beneath the plasma membrane of many cells, including animal cells and yeast cells, in a plane perpendicular to the axis of the meiotic spindle, i.e. the cell division plane. Ring contraction is associated with centripetal growth of the membrane that divides the cytoplasm of the two future daughter cells. In animal cells, the meiotic contractile ring is located inside the plasma membrane at the location of the cleavage furrow. In fungal cells, the meiotic contractile ring forms beneath the plasma membrane of the prospore envelope in preparation for completing cytokinesis.


stromule

description: Thin filamentous structure extending from the surface of all plastid types examined so far, including chloroplast, proplastid, etioplast, leucoplast, amyloplast, and chromoplast. In general, stromules are more abundant in tissues containing non-green plastids, and in cells containing smaller plastids. The primary function of stromules is still unresolved, although the presence of stromules markedly increases the plastid surface area, potentially increasing transport to and from the cytosol. Other functions of stromules, such as transfer of macromolecules between plastids and starch granule formation in cereal endosperm, may be restricted to particular tissues and cell types.


ventral disc lateral crest

description: Fibrillar repetitive structure surrounding the ventral disc edge in Giardia species (trophozoite stage). The composition of the lateral crest is not fully known yet.


prospore membrane leading edge

description: The region of the prospore membrane that extends to surround the spore nucleus; coated with specific proteins that are thought to play a role in prospore membrane organization.


smooth muscle dense body

description: Electron-dense region associated with a smooth muscle contractile fiber.


paranode region of axon

description: An axon part that is located adjacent to the nodes of Ranvier and surrounded by lateral loop portions of myelin sheath.


dendrite membrane

description: The portion of the plasma membrane surrounding a dendrite.


unicellular trichome branch

description: A cell projection part that is a branch of a unicellular trichome.


lateral loop

description: Non-compact myelin located adjacent to the nodes of Ranvier in a myelin segment. These non-compact regions include cytoplasm from the cell responsible for synthesizing the myelin. Lateral loops are found in the paranodal region adjacent to the nodes of Ranvier, while Schmidt-Lantermann clefts are analogous structures found within the compact myelin internode.


peptidoglycan-based cell wall

description: A protective structure outside the cytoplasmic membrane composed of peptidoglycan (also known as murein), a molecule made up of a glycan (sugar) backbone of repetitively alternating N-acetylglucosamine and N-acetylmuramic acid with short, attached, cross-linked peptide chains containing unusual amino acids. An example of this component is found in Escherichia coli.


description: An organelle arrangement comprised of the following elements: a mitochondrion positioned near the presynaptic membrane; an electron-dense mitochondrial plaque adjacent to the outer mitochondrial membrane that faces the presynaptic membrane; filament-like elements appearing to link the mitochondrial plaque to a cell-cell junction region (sometimes termed punctum adherens); tubular or vesicular-appearing membrane (also called vesicular chain) interposed among the filaments. Mitochondrion-associated adherens complexes were initially described in the dorsal horn of the spinal cord. They are found in calyces and other large terminals of the auditory brainstem, and in a variety of mammalian species including humans.


mitochondrial intracristal space

description: The space bounded by the mitochondrial cristae membranes, continuous with the intermembrane space.


pinceau fiber

description: Dense plexus formed by the descending collaterals of cerebellar basket cells that wrap around a Purkinje cell axonal initial segment.


neuron projection membrane

description: The portion of the plasma membrane surrounding a neuron projection.


attachment organelle

description: A membrane-bounded extension of the cell, originally characterized in Mycoplasma species, that contains an electron-dense core that is part of the cytoskeleton and is oriented lengthwise and ends distally in a bulbous knob (terminal button). Required for adherence to host cells and involved in gliding motility and cell division.


actin cap

description: Polarized accumulation of cytoskeletal proteins (including F-actin) and regulatory proteins in a cell. An example of this is the actin cap found in Saccharomyces cerevisiae.


name: endoplasmic reticulum-Golgi intermediate compartment membrane

description: The lipid bilayer surrounding any of the compartments of the endoplasmic reticulum (ER)-Golgi intermediate compartment system.


cell septum edging

description: The cell wall material that surrounds the septum in fungal cells.


varicosity

description: Non-terminal inflated portion of the axon, containing the specialized apparatus necessary to release neurotransmitters.


annulate lamellae

description: Stacks of endoplasmic reticulum (ER) membranes containing a high density of nuclear pores, thought to form from excess nuclear membrane components, that have been described in a number of different cells. Annulate lamellar membranes are continuous with and embedded within the ER.


ventral disc dorsal microribbon

description: Trilaminar structure extending perpendicularly into the cytoplasm along the length of ventral disc microtubules in Giardia species (trophozoite stage). Constituents of dorsal microribbons (also called dorsal ribbons or microribbons) include alpha-coiled-helix proteins approximately 29 to 38 kDa in size. These proteins line the edges of the microribbons but are not found in microtubules. Tubulins are not found in microribbons.


porosome

description: A permanent cup-shaped structure at the cell plasma membrane in secretory cells. Following a secretory stimulus, secretory vesicles transiently dock and fuse at the base of porosomes and release intravesicular contents dictated by the turgor pressure generated from the swelling of secretory vesicles.


longitudinal sarcoplasmic reticulum

description: The portion of the free sarcoplasmic reticulum consisting of longitudinal tubules that connect terminal cisternae.


left middle basal body pair

description: Set of two basal bodies found in Giardia species (trophozoite stage). It comprises the caudal and posteriolateral basal bodies located to the right of the left nucleus of the trophozoite when viewed dorsally.


pericentriolar material

description: A network of small fibers that surrounds the centrioles in cells; contains the microtubule nucleating activity of the centrosome.


presynaptic endocytic zone membrane

description: The region of the presynaptic membrane that is part of the presynaptic endocytic zone - where synaptic vesicles are endocytosed and recycled following release.


median body

description: A non-membrane bound, semi-organized microtubule array of unknown function found in Giardia species (trophozoite stage). It is located on the dorsal side of the trophozoite, slightly posterior to the ventral disc.


mononeme

description: A secretory organelle that forms part of the apical complex; a small, threadlike structure located is close proximity to the subpellicular microtubules. Its contents include a rhomboid protease (PfROM1 in Plasmodium falciparum) that moves from the lateral asymmetric localization to the merozoite apical pole and the posterior pole upon release of merozoites from schizonts.


glyoxysome

description: A specialized form of peroxisome that contains the enzymes of the glyoxylate pathway. The glyoxysome is found in some plant cells, notably the cells of germinating seeds.


ciliary rootlet

description: A cytoskeleton-like structure, originating from the basal body at the proximal end of a cilium, and extending proximally toward the cell nucleus. Rootlets are typically 80-100 nm in diameter and contain cross striae distributed at regular intervals of approximately 55-70 nm.


stereocilia tip-link density

description: An electron-dense plaque at either end of a stereocilia tip link that provides the anchor in the stereocilia membrane.


preprophase band

description: A dense band of microtubules, 1-3 pm wide, that appears just beneath the cell membrane before the start of cell division in the cells of higher plants. It precedes the onset of prophase and then disappears as mitosis begins, yet it somehow determines the plane of orientation of the new cell plate forming in late telophase and marks the zone of the parental cell wall where fusion with the growing cell plate ultimately occurs.


inner plaque of spindle pole body

description: One of three laminate structures that form the spindle pole body; the inner plaque is in the nucleus.


mating projection septin band

description: A septin band, i.e. a diffuse ring composed of a series of septin bars running parallel to the long axis of the cell, located at the neck of a shmoo (mating projection).


stereocilia ankle link

description: A stereocilia coupling link that is composed of a fine filament present in developing stereocilia that couples the bases of individual stereocilia to one another. They are not present in mature stereocilia.


stereocilium base

description: The tapered base of the stereocilium adjacent to where it joins the hair cell body. This region contains a rootlet comprised of bundled actin filaments which spans the joint and stabilizes the stereocilium.


phagocytic cup base

description: The older part of the phagocytic cup where the actin cytoskeleton disassembles, allowing early incoming and outgoing vesicular trafficking.


apical complex

description: A group of cytoskeletal structures and associated membrane-bounded organelles found at the anterior end of adult obligate intracellular protozoan parasites in the phylum Apicomplexa. The apical complex is involved in attachment to and penetration of the host cell, and in parasite proliferation.


ocelloid

description: Eye-like subcellular structure found in dinoflagellates (a large group of single-celled eukaryotes). Consists of subcellular analogues to a cornea, lens, iris, and retina. Ocelloids are built from pre-existing organelles, including a cornea-like layer made of mitochondria and a retinal body made of anastomosing plastids.


endosome lumen

description: The volume enclosed by the membrane of an endosome.


exoneme

description: A dense granule-like organelle of the apical complex of merozoites, released into the parasitophorous vacuole, mediating protease-dependent rupture and parasite exit from the infected erythrocyte.


juxtaparanode region of axon

description: A region of an axon near a node of Ranvier that is between the paranode and internode regions.


hyphal membrane

description: A host-derived membrane surrounding the symbiont hypha during infection.


bacterial-type flagellum filament cap

description: The proteinaceous structure at the distal tip of the bacterial-type flagellar filament.


description: Organized structure of distinctive morphology and function, bounded by a lipid bilayer membrane and occurring outside the cell.


magnetosome lumen

description: The volume enclosed by the membrane of a magnetosome.


axonemal B tubule inner sheath

description: A structural network of microtubule inner proteins (MIPs) located inside the lumen of the B tubule of the axonemal microtubule doublet that helps stabilize the B tubule.


primary cell septum

description: A cell septum that forms following nuclear division.


virus-like capsid

description: A protein coat that surrounds nucleic acid to form a structure similar to a virus capsid. Virus-like capsids are non-infectious and are encoded by endogenous (non-viral) genes. Fly and tetrapod Arc (ancestrally-related to retrotransposon Gag) are examples of proteins that can self-assemble into capsid-like structures which encapsulate Arc mRNA and mediate the intercellular transmission of RNA.


subplasmalemmal coating

description: Electron dense material observed coating the cytoplasmic face of the plasma membrane in certain regions of a neuron, e.g., the axon initial segment; the nodal membrane at the Node of Ranvier.


cellularization cleavage furrow

description: A plasma membrane invagination at the site of separation of a multi-nucleate cell or syncytium into individual cells.


basolateral part of cell

description: The region of a cell situated by the cell sides which interface adjacent cells and near the base. Often used in reference to animal polarized epithelial cells.


stereocilium shaft

description: The shaft comprises the majority of the length of the stereocilium. This region is notable for the extreme stability of actin filaments, which are highly crosslinked into a parallel bundle.


medial cortical node

description: A component of the cell division site that contains the mid1, cdr2, wee1, klp8, and blt1 proteins, and is involved in contractile ring localization. Medial cortical node complexes appear as cortical dots in the middle of the cell during interphase, and function to recruit other ring components in early mitosis.


compact myelin

description: The portion of the myelin sheath in which layers of cell membrane are tightly juxtaposed, completely excluding cytoplasm. The juxtaposed cytoplasmic surfaces form the major dense line, while the juxtaposed extracellular surfaces form the interperiod line visible in electron micrographs.


reservosome matrix

description: A matrix composed of planar membranes, vesicles and lipid inclusions within the reservosome.


cortical dynamic polarity patch

description: A region of the cell cortex that contains a higher concentration of growth polarity factors than the surrounding cortex and that changes position over time. An example is found in fission yeast cells during early mating, in which the GTPase Cdc42 dynamically to discrete zones within the cortex prior to shmoo formation.


centrosomal core

description: The core region of the centrosome, a layered structure containing proteins, surrounded by the centrosomal corona. The core duplicates once per cell cycle at the G2/M transition when two outer layers form the mitotic spindle poles.


stereocilia coupling link

description: A structure involved in coupling stereocilia to one another in sensory hair cells There are four morphologically distinct types: tip links, horizontal top connectors, shaft connectors and ankle links. Tip links and horizontal top connectors are the only inter-stereocilia links associated with mature cochlea, whereas ankle links appear during development of the auditory hair bundle.


postsynaptic endocytic zone membrane

description: The region of the postsynaptic membrane that is part of the postsynaptic endocytic zone. This region of membrane is associated with stable clathrin puncta.


germinal vesicle

description: The enlarged, fluid filled nucleus of a primary oocyte, the development of which is suspended in prophase I of the first meiotic division between embryohood and sexual maturity.


outer dense plaque of desmosome

description: The desmosomal part containing plakoglobins, plakophilins, the N-termini of desmoplakins, as well as the cytoplasmic tails of the desmosomal cadherins, which together attach the plaque to the plasma membrane.


name: organellar chromatophore thylakoid lumen

description: The volume enclosed by an organellar chromatophore thylakoid membrane.


etioplast membrane

description: Either of the lipid bilayers that surround a etioplast and form the etioplast envelope.


hyphal cell wall

description: The cell wall surrounding a fungal hypha.


Schaffer collateral - CA1 synapse

description: A synapse between the Schaffer collateral axon of a CA3 pyramidal cell and a CA1 pyramidal cell.


host intracellular region

description: That space within the plasma membrane of a host cell.


retrotransposon nucleocapsid

description: A complex of the retrotransposon RNA genome, reverse transcriptase, integrase, and associated molecules required for reproduction and integration of the retrotransposon into the host genome; the main structural molecule of the nucleocapsid is often a gag protein homolog.


stereocilium coat

description: A glycocalyx on the the endolymphatic surface of a cochlear hair cell that coats the external surface of each stereocilium and maintains a small distance between adjacent stereocilia in the bundle.


symmetric synapse

description: A synapse that lacks an electron dense postsynaptic specialization. In vertebtrates, these occur primarily on dendrite shafts and neuronal cell bodies and involve persynapses containing clusters of predominantly flattened or elongated vesicles and are typically inhibitory.


mitochondrial membrane scission site

description: The site on the mitochondrial membrane where the separation of a single continuous mitochondrial membrane into two membranes occurs as a final step in mitochondrial fission.


extracellular vesicle

description: Any vesicle that is part of the extracellular region.


acidocalcisome lumen

description: The volume enclosed by the membranes of an acidocalcisome.


basolateral cytoplasm

description: The region of the cytoplasm located at the basolateral side of the cell. Used in reference to animal polarized epithelial cells.


deep fiber

description: Inward projections of the cytoskeletal structures of the oral apparatus, which form a fiber that extends past the cytostome into the cytoplasm.


name: hinge region between urothelial plaques of apical plasma membrane

description: A narrow rim of non-thickened membrane in between urothelial plaques in apical plasma membrane.


plant-type vacuole lumen

description: The volume enclosed within the vacuolar membrane of a vacuole that retains the same shape regardless of cell cycle phase. An example of this is found in Arabidopsis thaliana.


name: bacterial-type flagellum secretion apparatus

description: A part of the bacterial-type flagellum that is located at the cytoplasmic side of the MS ring and composed of six membrane proteins (FlhA, FlhB, FliP, FliQ, FliR, and FliO, or orthologs thereof) and three soluble proteins (FliI, FliH, and FliJ, or orthologs thereof) in the cytoplasm. It is responsible for secretion of flagellar type III protein substrates, including the proteins of the flagellar rod, hook, and filament.


axon hillock

description: Portion of the neuronal cell soma from which the axon originates.


annuli extracellular matrix

description: The extracellular matrix that is a regularly spaced circumferential ridge present in the cortical region of the cuticle. Annuli are delineated by annular furrows and are present throughout the cuticle with the exception of lateral regions where longitudinal alae are present.


basal pole of outer hair cell

description: The end of the outer hair cell which receives and transmits neural signals.


arbuscule

description: Highly branched symbiont haustoria within host root cortex cells, responsible for nutrient exchange.


host peribacteroid fluid

description: The soluble material inside the peribacteroid membrane, but outside of the bacteroid, within a bacteroid-containing symbiosome of a host cell.


plasma membrane of cell tip

description: The portion of the plasma membrane surrounding the cell tip.


mitotic spindle pole

description: Either of the ends of a mitotic spindle, a spindle that forms as part of mitosis, where spindle microtubules are organized; usually contains a microtubule organizing center and accessory molecules, spindle microtubules and astral microtubules.


sarcoplasmic reticulum membrane

description: The lipid bilayer surrounding the sarcoplasmic reticulum.


serotonergic synapse

description: A synapse that uses serotonin as a neurotransmitter.


neuronal cell body membrane

description: The plasma membrane of a neuron cell body - excludes the plasma membrane of cell projections such as axons and dendrites.


apoptotic body

description: A vesicle containing parts of a dying cell. Apoptotic bodies can be formed during the execution phase of the apoptotic process, when the cell's cytoskeleton breaks up and causes the membrane to bulge outward. These bulges may separate from the cell, taking a portion of cytoplasm with them, to become apoptotic bodies. These are then engulfed by phagocytic cells, and their components recycled. Apoptotic bodies may range in size from 0.8 to 5um.


name: host cell endoplasmic reticulum membrane

description: The lipid bilayer surrounding the host cell endoplasmic reticulum.


name: mitotic nuclear bridge midzone membrane domain

description: A nuclear membrane part at the midzone of the mitotic nuclear bridge. The midzone forms a bulge that is enriched in nuclear pores that lack baskets.


microbody membrane

description: The lipid bilayer surrounding a microbody.


dendritic growth cone

description: The migrating motile tip of a growing nerve cell dendrite.


blood microparticle

description: A phospholipid microvesicle that is derived from any of several cell types, such as platelets, blood cells, endothelial cells, or others, and contains membrane receptors as well as other proteins characteristic of the parental cell. Microparticles are heterogeneous in size, and are characterized as microvesicles free of nucleic acids.


right anterior basal body

description: Any ciliary basal body that is part of a right anterior flagellum found in Giardia species (trophozoite stage).


Schmidt-Lanterman incisure

description: Regions within compact myelin in which the cytoplasmic faces of the enveloping myelin sheath are not tightly juxtaposed, and include cytoplasm from the cell responsible for making the myelin. Schmidt-Lanterman incisures occur in the compact myelin internode, while lateral loops are analogous structures found in the paranodal region adjacent to the nodes of Ranvier.


presynaptic endocytic zone

description: A specialized region of the plasma membrane and underlying cytoplasm which surround the the active zone, into which synaptic vesicle membranes are recycled following exocytosis. It is especially enriched in endocytic proteins following intense activity.


dendritic spine head

description: Distal part of the dendritic spine, that carries the post-synaptic density.


name: extrinsic component of cell outer membrane

description: The component of the cell outer membrane consisting of gene products and protein complexes that are loosely bound to one of its surfaces, but not integrated into the hydrophobic region.


cell tip

description: The region at the end of the longest axis of a cylindrical or elongated cell.


central cylinder

description: A scaffolding structure present within the inner region of the ciliary transition zone. The central cylinder lies between the outer doublet and inner singlet microtubules.


polar nucleus

description: Either of two nuclei located centrally in a flowering plant embryo sac that eventually fuse to form the endosperm nucleus.


name: mitotic actomyosin contractile ring, proximal layer

description: The region of the mitotic actomyosin ring adjacent to the plasma membrane where membrane bound scaffolds are located.


mating projection actin fusion focus

description: A focus at the mating projection tip where the cell wall is degraded during conjugation with cellular fusion. Actin filaments form an aster-like structure from this location.


growth cone membrane

description: The portion of the plasma membrane surrounding a growth cone.


external side of cell wall

description: The side of the cell wall that is opposite to the side that faces the cell and its contents.


early recombination nodule

description: An electron dense structure that is associated with meiotic chromosomes in leptotene or zygotene during meiosis I.


name: bacterial-type flagellum basal body, distal rod, L ring

description: One of the rings of the bacterial-type flagellar basal body; anchors the basal body to the outer membrane.


right posteriolateral basal body

description: Any ciliary basal body that is part of a right posteriolateral flagellum found in Giardia species (trophozoite stage).


gut granule lumen

description: The lumen of a gut granule, a lysosome-related organelle contained within the intestinal cells of the nematode C. elegans.


protein storage vacuole lumen

description: The volume enclosed by the protein storage vacuole membrane.


cone photoreceptor outer segment

description: The outer segment of a vertebrate cone photoreceptor that contains membrane discs that are contiguous with the ciliary membrane and containing opsin photoreceptor proteins.


autophagosome lumen

description: The volume enclosed within the autophagosome double-membrane.


plasmodesmatal desmotubule

description: A tightly wound cylinder of membrane that is located within the plasmodesmal pore and runs the length of the plasmodesma. The desmotubule likely provides a rigid stability to plasmodesmata and confers a fixed diameter and pore size to the plasmodesmal canal, and is linked to the endoplasmic reticulum in each of the adjacent cell.


smooth endoplasmic reticulum lumen

description: The volume enclosed by the membranes of the smooth endoplasmic reticulum.


sexine

description: The outer, sculptured layer of the exine, which lies above the nexine.


septal periplasm

description: The region between the plasma membrane and the cell wall, as found in organisms such as filamentous fungi.


dopaminergic synapse

description: A synapse that uses dopamine as a neurotransmitter.


platelet dense tubular network membrane

description: The lipid bilayer surrounding the platelet dense tubular network.


noradrenergic synapse

description: A synapse that uses noradrenaline as a neurotransmitter.


description: The part of the sarcoplasmic reticulum membrane that contains calcium release channels, is devoted to calcium release and is juxtaposed to transverse tubule membrane. The junctional sarcoplasmic reticulum membrane consists of the junctional region of the terminal cisterna membrane.


symplast

description: The interconnected cell membranes and intracellular regions of a plant. The interconnections occur via the plasmodesmata.


name: postsynaptic specialization of symmetric synapse

description: A network of proteins within and adjacent to the postsynaptic membrane of a symmetric synapse, consisting of anchoring and scaffolding molecules, signaling enzymes and cytoskeletal components that spatially and functionally organize the neurotransmitter receptors at the synapse. This structure is not as thick or electron dense as the postsynaptic densities found in asymmetric synapses.


xanthophore

description: A chromatophore containing yellow pigment.


name: perinuclear endoplasmic reticulum membrane

description: The membrane of the perinuclear endoplasmic reticulum, which is the portion of endoplasmic reticulum, the intracellular network of tubules and cisternae, that occurs near the nucleus.


secondary cell septum

description: Cell wall structures composed of linear polysaccharides which are deposited at both sides of the primary septum at 90 degrees to the primary septum.


mitotic nuclear bridge stalk

description: Either of the regions of a mitotic nuclear bridge proximal to the main portion of each daughter nucleus. The nuclear envelope in the stalk regions is depleted of nuclear pore complexes.


cytoplasmic side of nuclear pore

description: The side of the nuclear pore complex (NPC) that faces the cytoplasm.


right nucleus

description: One of the two nuclei found in Giardia species (trophozoite stage). It is located on the right side of the cell when viewed from the dorsal side.


dityrosine layer of spore wall

description: The outermost layer of the spore wall, as described in Saccharomyces.


nuclear lamina

description: The fibrous, electron-dense layer lying on the nucleoplasmic side of the inner membrane of a cell nucleus, composed of lamin filaments. The polypeptides of the lamina are thought to be concerned in the dissolution of the nuclear envelope and its re-formation during mitosis. The lamina is composed of lamin A and lamin C filaments cross-linked into an orthogonal lattice, which is attached via lamin B to the inner nuclear membrane through interactions with a lamin B receptor, an IFAP, in the membrane.


peripheral region of growth cone

description: The non-central region or periphery of the migrating motile tip of a growing nerve cell axon or dendrite.


yolk

description: The cytoplasmic part that serves as a nutrient reserve or energy source for the developing embryo.


basal ring of apical complex

description: An electron dense ring at the most posterior position of the apical complex, from which the subpellicular microtubules originate; formed during an invasive life cycle stage of an apicomplexan parasite.


chromoplast intermembrane space

description: The region between the inner and outer lipid bilayers of a chromoplast envelope.


basal pole of neuron

description: Portion of a neuron cell soma closest to the point where the basilar dendrite emerges.


rough endoplasmic reticulum cisterna

description: A subcompartment of the rough endoplasmic reticulum consisting of lumenal expansion into a flattened, disc-shaped cavity.


name: mitotic actomyosin contractile ring, distal actin filament layer

description: The region of the mitotic actomyosin ring containing actin filaments and cross linkers, myosin motors, and connections to the plasma membrane through the intermediate layer. It is further from the plasma membrane than the intermediate layer which it is adjacent to.


organelle envelope lumen

description: The region between the inner and outer lipid bilayers of an organelle envelope.


centrosomal corona

description: An amorphous structure surrounding the core of the centrosome, from which microtubules are nucleated; contains gamma-tubulin.


dendritic branch point

description: The part of a dendritic tree where it branches, giving rise to a dendritic branch.


upper tip-link density

description: An electron-dense plaque at the upper end of a stereocilia tip link that provides the anchor in the stereocilia membrane on the side of the stereocilium where the tip link ends.


fungal-type vacuole lumen

description: The volume enclosed within the vacuolar membrane of a vacuole, the shape of which correlates with cell cycle phase. An example of this structure is found in Saccharomyces cerevisiae.