The cell membrane of the host cell invaginates the virus particle, enclosing it in a pinocytotic vacuole. This protects the cell from antibodies like in the case of the HIV virus.
|
|
During the earlier stages of embryogenesis, the otic placode invaginates to produce the otic cup. Thereafter, the otic cup closes off, creating the otic vesicle. Once formed, the otic vesicle will reside next to the neural tube medially, and on the lateral side will be paraxial mesoderm. Neural crest cells will migrate rostral and caudal to the placode.
|
|
Lingual tonsils are covered externally by stratified squamous nonkeratinized epithelium that invaginates inward forming crypts. Beneath the epithelium is a layer of lymphoid nodules containing lymphocytes. Mucous glands located at the root of tongue are drained through several ducts into the crypt of lingual tonsils. Secretions of these mucous glands keep the crypt clean and free of any debris.
|
|
The hypodermis, otherwise known as the subcutaneous layer, is a layer beneath the skin. It invaginates into the dermis and is attached to the latter, immediately above it, by collagen and elastin fibers. It is essentially composed of a type of cell known as adipocytes specialized in accumulating and storing fats. These cells are grouped together in lobules separated by connective tissue.
|
|
It is an example of fluid phase endocytosis and is usually a continuous process within the cell. The particles are absorbed through the use of clathrin-coated pits. These clathrin-coated pits are short lived and serve only to form a vesicle for transfer of particles to the lysosome. The clathrin-coated pit invaginates into the cytosol and forms a clathrin-coated vesicle.
|
|
The upper part of the anal canal is derived from endoderm of the hindgut. The lower part (one-third) is derived from ectoderm around the proctodeum. Ectoderm, in the region of the proctodeum on the surface of part of the cloaca, proliferates and invaginates to create the anal pit. Subsequently, degeneration of the cloacal membrane establishes continuity between the upper and lower parts of the anal canal.
|
|
Embryology is suggested to have an intimate association with the development of caudal duplication syndrome. At day 15 after fertilisation, the notochord grows from the primitive knot, in which it invaginates and forms the notochord canal within. Progressively, on day 20, the ventral wall of the notochord dissolves, while communications are formed between the amniotic and yolk sac. One such connection is the Kovalevsky’s canal.
|
|
Macrophages become activated in chronic diseases such as rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, atherosclerosis, diabetes, and most other inflammatory diseases. From a mechanistic perspective, the FR functions to concentrate exogenous ligands (e.g. folates and folate-drug conjugates) into the cell cytosol by endocytosis. The term endocytosis refers to the process whereby the plasma membrane invaginates and eventually forms a distinct intracellular compartment.
|
|
A synovial sheath is one of the two membranes of a tendon sheath which covers a tendon. The other membrane is the outer fibrous tendon sheath.eMedicine/Stedman Medical Dictionary Lookup! The tendon invaginates the synovial sheath from one side so that the tendon is suspended from the membrane by the mesotendon, through which the blood vessels reach the tendon, in places where the range of movement is extensive.
|
|
Adult males and females emerge from the ground in the autumn. The female climbs up a tree, post or any other vertical surface and this is where mating takes place. After mating, the female attaches herself to a surface and invaginates her abdomen, creating a "marsupium" in which she lays a batch of eggs. She dies soon thereafter, her cuticle making a leathery protective casing for the eggs.
|
|
Endocytosis is the reverse of exocytosis and can occur in a variety of forms. Phagocytosis ("cell eating") is the process by which bacteria, dead tissue, or other bits of material visible under the microscope are engulfed by cells. The material makes contact with the cell membrane, which then invaginates. The invagination is pinched off, leaving the engulfed material in the membrane-enclosed vacuole and the cell membrane intact.
|
|
Entry of material into the nucleus through endocytosis. Endocytosis: The membrane of the cell invaginates, creating a small circular pit that is taken into the cytosol of the cell. This circular membrane coated pit is a vesicle that is transported to the lysosome of the cell to be degraded by enzymes. Cytosis is a transport mechanism for the movement of large quantities of molecules into and out of cells.
|
|
Sometimes, rather than being degraded, the receptors that were endocytosed along with the ligand are then returned to the plasma membrane to continue the process of endocytosis. Mechanism of clathrin-dependent endocytosis. Clathrin- coated pits in endocytosis: The membrane of the cell invaginates using the protein clathrin. The clathrin uses actin to pull together the sides of the plasma membrane and form a vesicle inside the cellular cytosol.
|
|
The endomembrane system and its components Eukaryote cells include a variety of membrane-bound structures, collectively referred to as the endomembrane system. Simple compartments, called vesicles and vacuoles, can form by budding off other membranes. Many cells ingest food and other materials through a process of endocytosis, where the outer membrane invaginates and then pinches off to form a vesicle. It is probable that most other membrane-bound organelles are ultimately derived from such vesicles.
|
|
The nematocyst forms through a multi-step assembly process from a giant post-Golgi vacuole. Vesicles from the Golgi apparatus first fuse onto a primary vesicle: the capsule primordium. Subsequent vesicle fusion enables the formation of a tubule outside of the capsule, which then invaginates into the capsule. Then, an early maturation phase enables the formation of long arrays of barbed spines onto the invaginated tubule through the condensation of spinalin proteins.
|
|
This development is induced by the ventral part of the forebrain. In the sixth week the ectoderm in each nasal placode invaginates to form an indented oval-shaped pit, which forms a surrounding raised ridge of tissue. Each nasal pit forms a division between the ridges, into a lateral nasal process on the outer edge, and a medial nasal process on the inner edge. In the sixth week the nasal pits deepen as they penetrate into the underlying mesenchyme.
|
|
Replication of the viral RNA begins with the migration of p28 to the mitochondrial membrane. p28 migrates to and invaginates the outer mitochondrial membrane; several p88 molecules are brought the newly formed vesicles. The viral RNA binds to the p28 bound to the membrane and the RNA dependent RNA polymerase, or p88, initiates replication of the positive strand RNA to produce a minus strand intermediate. The negative-strand intermediate is used as a template to produce progeny positive strand RNA.
|
|
Mollusc shells in Manchester Museum The shell-secreting area is differentiated very early in embryonic development. An area of the ectoderm thickens, then invaginates to become a "shell gland". The shape of this gland is tied to the form of the adult shell; in gastropods, it is a simple pit, whereas in bivalves, it forms a groove which will eventually become the hinge line between the two shells, where they are connected by a ligament. The gland subsequently evaginates in molluscs that produce an external shell.
|
|
During clathrin-mediated endocytosis, the cell membrane invaginates to form a budding vesicle. Dynamin binds to and assembles around the neck of the endocytic vesicle, forming a helical polymer arranged such that the GTPase domains dimerize in an asymmetric manner across helical rungs. The polymer constricts the underlying membrane upon GTP binding and hydrolysis via conformational changes emanating from the flexible neck region that alters the overall helical symmetry. Constriction around the vesicle neck leads to the formation of a hemi-fission membrane state that ultimately results in membrane scission.
|
|
Further induction by the chordamesoderm will form a protrusion: the optic vesicle. This vesicle will be subsequently invaginated by means of further inductions from the chordamesoderm. The optic vesicle will then induce the ectoderm that thickens (lens placode) and further invaginates to a point that detaches from the ectoderm and forms a neurogenic placode by itself. The lens placode is affected by the chordamesoderm making it to invaginate and forms the optic cup composed by an inner layer of neural retina and outer layer the pigmented retina that will unite and form the optic stalk.
|
|
The human inner ear develops during week 4 of embryonic development from the auditory placode, a thickening of the ectoderm which gives rise to the bipolar neurons of the cochlear and vestibular ganglions. As the auditory placode invaginates towards the embryonic mesoderm, it forms the auditory vesicle or otocyst. The auditory vesicle will give rise to the utricular and saccular components of the membranous labyrinth. They contain the sensory hair cells and otoliths of the macula of utricle and of the saccule, respectively, which respond to linear acceleration and the force of gravity.
|
|
At infection of an orchid by a mycorrhizal fungus both partners are altered considerably to allow for nutrient transfer and symbiosis. Nutrient transfer mechanisms and the symbiotic mycorrhizal peloton organs start to appear only shortly after infection around 20–36 hours after initial contact. There is significant genetic upregulation and downregulation of many different genes to facilitate the creation of the symbiotic organ, and the pathways with which nutrients travel. As the fungus enters the parenchyma cells of the orchid the plasma membrane invaginates to facilitate fungal infection and growth.
|
|
In prokaryotes (bacteria and archaea) this usually occurs via a relatively simple process called binary fission, in which each circular genome attaches to the cell membrane and is separated into the daughter cells as the membrane invaginates to split the cytoplasm into two membrane-bound portions. Binary fission is extremely fast compared to the rates of cell division in eukaryotes. Eukaryotic cell division is a more complex process known as the cell cycle; DNA replication occurs during a phase of this cycle known as S phase, whereas the process of segregating chromosomes and splitting the cytoplasm occurs during M phase.
|
|
The germ line segregates from the somatic cells through the formation of pole cells at the posterior end of the embryo. After thirteen mitotic divisions and about 4 hours after fertilization, an estimated 6,000 nuclei accumulate in the unseparated cytoplasm of the oocyte before they migrate to the surface and are encompassed by plasma membranes to form cells surrounding the yolk sac producing a cellular blastoderm. Like other triploblastic metazoa, gastrulation leads to the formation of three germ layers: the endoderm, mesoderm, and ectoderm. The mesoderm invaginates from the ventral furrow (VF), as does the ectoderm that will give rise to the midgut.
|
|
The membrane invaginates and disks bud off internally, forming the tightly packed stacks of outer segment disks. From translation of opsin to formation of the disks takes just a couple of hours. In a famous 1967 paper – The Renewal of Photoreceptor Cell Outer Segments – Professor Richard Young described his observations that new discs are assembled at the base of the outer segment – the ciliary plasmalemma – by incorporating proteins and lipids that are synthesized and transported from the inner segment. Discs mature along with their distal migration; aged discs shed at the distal tip and are engulfed by the neighboring retinal pigment epithelial cells for degradation.
|
|
Development of the neural tube During the third week of embryonic growth the brain begins to develop in the early fetus in a process called morphogenesis. Neuroepithelial cells of the ectoderm begin multiplying rapidly and fold in forming the neural plate, which invaginates during the fourth week of embryonic growth and forms the neural tube. The formation of the neural tube polarizes the neuroepithelial cells by orienting the apical side of the cell to face inward, which later becomes the ventricular zone, and the basal side is oriented outward, which contacts the pial, or outer surface of the developing brain. As part of this polarity, neuroepithelial cells express prominin-1 in the apical plasma membrane as well as tight junctions to maintain the cell polarity.
|
|
It is seen in 1% of the population. Embryologically, it arises from an anomalous lateral course of the azygos vein in a pleural septum within the apical segment of the right upper lobe or in other words an azygos lobe is formed when the right posterior cardinal vein, one of the precursors of the azygos vein, fails to migrate over the apex of the lung and penetrates it instead, carrying along two pleural layers that invaginates into the upper portion of the right upper lobe . As it has no bronchi, veins and arteries of its own or corresponding alteration in the segmental architecture of the lung, so it is not a true (misnomer), or even accessory, pulmonary lobe, but rather an anatomically separated part of the upper lobe. It is usually an incidental finding on chest x-ray or computed tomography and is as such not associated with any morbidity but can cause technical problems in thoracoscopic procedures .
|
|