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Follicular Atresia
Follicular atresia refers to the process in which a Ovarian follicle, follicle fails to develop, thus preventing it from Ovulation, ovulating and releasing an egg. It is a normal, naturally occurring progression that occurs as mammalian Ovary, ovaries age. Approximately 1% of mammalian follicles in ovaries undergo ovulation and the remaining 99% of follicles go through follicular atresia as they cycle through the growth phases. In summary, follicular atresia is a process that leads to the follicular loss and loss of oocytes, and any disturbance or loss of functionality of this process can lead to many other conditions. Background Ovary, Ovaries are the site of development and breakdown of ovarian follicles which secrete hormones and Oocyte, oocytes. Oocytes are immature eggs and are surrounded by granulosa cells and internal and external theca cells. Oocytes are then able to mature within the follicle through meiosis. In humans with ovaries, this process occurs continuously, as th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Follicle-stimulating Hormone
Follicle-stimulating hormone (FSH) is a gonadotropin, a glycoprotein polypeptide hormone. FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland and regulates the development, growth, puberty, pubertal maturation, and reproductive processes of the body. FSH and luteinizing hormone (LH) work together in the reproductive system. Structure FSH is a 35.5 kDa glycoprotein protein dimer, heterodimer, consisting of two polypeptide units, alpha and beta. Its structure is similar to those of luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and human chorionic gonadotropin (hCG). The chorionic gonadotropin alpha, alpha subunits of the glycoproteins LH, FSH, TSH, and hCG are identical and consist of 96 amino acids, while the beta subunits vary. Both subunits are required for biological activity. FSH has a beta subunit of 111 amino acids (FSH β), which confers its specific biologic action, and is responsible for interaction with the follicl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovarian Follicle
An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. In humans, women have approximately 200,000 to 300,000 follicles at the time of puberty, each with the potential to release an egg cell (ovum) at ovulation for Human fertilization, fertilization. These eggs are developed once every menstrual cycle with around 300-400 being ovulated during a woman's reproductive lifetime. Structure Ovarian follicles are the basic units of female reproductive biology. Each of them contains a single oocyte (immature ovum or egg cell). These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single competent oocyte in humans. They also consist of granulosa cells and theca of follicle. Oocyte Once a month, one of the ovaries releases a mature egg (ovum), known as an oocyte. The nucleus of such an oocyte is called a ''germinal vesicle (see picture).' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumor Necrosis Factors
The tumor necrosis factor (TNF) superfamily is a protein superfamily of transmembrane protein#Classification by topology, type II transmembrane proteins containing TNF homology domain and forming Protein trimer, trimers. Members of this superfamily can be released from the cell membrane by extracellular proteolytic cleavage and function as a cytokine. These proteins are expressed predominantly by immune cells and they regulate diverse cell functions, including immune response and inflammation, but also proliferation, differentiation, apoptosis and embryogenesis. The superfamily contains 19 members that bind to 29 members of TNF receptor superfamily. An occurrence of Sequence homology#Orthology, orthologs in invertebrates hints at ancient origin of this superfamily in evolution. The PROSITE pattern of this superfamily is located in a beta sheet in the central section of the protein that is conserved across all members. Members There are 19 family members, numerically classifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Oxide
Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral *Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide * Nitrogen dioxide (), nitrogen(IV) oxide * Nitrogen trioxide (), or nitrate radical *Nitrous oxide (), nitrogen(0,II) oxide * Dinitrogen dioxide (), nitrogen(II) oxide dimer * Dinitrogen trioxide (), nitrogen(II,IV) oxide * Dinitrogen tetroxide (), nitrogen(IV) oxide dimer *Dinitrogen pentoxide (), nitrogen(V) oxide, or nitronium nitrate * Nitrosyl azide (), nitrogen(−I,0,I,II) oxide * Nitryl azide () * Oxatetrazole () * Trinitramide ( or ), nitrogen(0,IV) oxide Anions Cations * Nitrosonium ( or ) * Nitronium ( or ) Atmospheric sciences In atmospheric chemistry: * (or NO''x'') refers to the sum of NO and . * (or NO''y'') refers to the sum of and all oxidized atmospheric odd-nitrogen species (''e.g.'' the sum of , , , etc.) * (or NO''z'') = − * Mixed Oxides of Nitrogen ("MON"): solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FLICE
Caspase-8 is a caspase protein, encoded by the ''CASP8'' gene. It most likely acts upon caspase-3. ''CASP8'' orthologs have been identified in numerous mammals for which complete genome data are available. These unique orthologs are also present in birds. Function The ''CASP8'' gene encodes a member of the cysteine-aspartic acid protease (caspase) family. Sequential activation of caspases plays a central role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes composed of a prodomain, a large protease subunit, and a small protease subunit. Activation of caspases requires proteolytic processing at conserved internal aspartic residues to generate a heterodimeric enzyme consisting of the large and small subunits. This protein is involved in the programmed cell death induced by Fas and various apoptotic stimuli. The N-terminal FADD-like death effector domain of this protein suggests that it may interact with Fas-interacting protein FADD. This protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspases
Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cysteine protease activity – a cysteine in its active site nucleophilically attacks and cleaves a target protein only after an aspartic acid residue. As of 2009, there are 12 confirmed caspases in humans and 10 in mice, carrying out a variety of cellular functions. The role of these enzymes in programmed cell death was first identified in 1993, with their functions in apoptosis well characterised. This is a form of programmed cell death, occurring widely during development, and throughout life to maintain cell homeostasis. Activation of caspases ensures that the cellular components are degraded in a controlled manner, carrying out cell death with minimal effect on surrounding tissues. Caspases have other identified roles in programmed cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspase 3
Caspase-3 is a caspase protein that interacts with caspase-8 and caspase-9. It is encoded by the ''CASP3'' gene. ''CASP3'' orthologs have been identified in numerous mammals for which complete genome data are available. Unique orthologs are also present in birds, lizards, lissamphibians, and teleosts. The CASP3 protein is a member of the cysteine-aspartic acid protease ( caspase) family. Sequential activation of caspases plays a central role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes that undergo proteolytic processing at conserved aspartic residues to produce two subunits, large and small, that dimerize to form the active enzyme. This protein cleaves and activates caspases 6 and 7; and the protein itself is processed and activated by caspases 8, 9, and 10. It is the predominant caspase involved in the cleavage of amyloid-beta 4A precursor protein, which is associated with neuronal death in Alzheimer's disease. Alternative splicing of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRAIL
A trail, also known as a path or track, is an unpaved lane or a small paved road (though it can also be a route along a navigable waterways) generally not intended for usage by motorized vehicles, usually passing through a natural area. However, it is sometimes applied to highways in North America. In the United Kingdom and Ireland, a path or footpath is the preferred term for a pedestrian or hiking trail. In the US, the term was historically used for a route into or through wild territory used by explorers and migrants (e.g. the Oregon Trail). In the United States, "trace" is a synonym for trail, as in Natchez Trace. Some trails are restricted to use by only walkers, or cyclists, or equestrians, or for snowshoeing, or cross-country skiing, others, for example bridleways in the UK, are shared, and can be used by walkers, cyclists and equestrians. Although most ban motorized use, there are unpaved trails used by dirt bikes, quad bikes and other off-road vehicles, u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fas Receptor
The Fas receptor, also known as Fas, FasR, apoptosis antigen 1 (APO-1 or APT), cluster of differentiation 95 (CD95) or tumor necrosis factor receptor superfamily member 6 (TNFRSF6), is a protein that in humans is encoded by the ''FAS'' gene. Fas was first identified using a monoclonal antibody generated by immunizing mice with the FS-7 cell line. Thus, the name Fas is derived from ''F''S-7-''a''ssociated ''s''urface antigen. The Fas receptor is a death receptor on the surface of cells that leads to programmed cell death (apoptosis) if it binds its ligand, Fas ligand (FasL). It is one of two apoptosis pathways, the other being the mitochondrial pathway. Gene FAS receptor gene is located on the long arm of chromosome 10 (10q24.1) in humans and on chromosome 19 in mice. The gene lies on the plus ( Watson strand) and is 25,255 bases in length organized into nine protein encoding exons. Similar sequences related by evolution ( orthologs) are found in most mammals. Protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fas Ligand
Fas ligand (FasL, also known as CD95L or Apo-1L) is a type-II transmembrane protein in the tumor necrosis factor (TNF) superfamily. It binds to the Fas receptor (CD95) to induce apoptosis, and also activates non-apoptotic pathways such as NF-κB and Mitogen-activated protein kinase, MAPK. FasL exists in membrane-bound and soluble forms, and is primarily expressed by cytotoxic T lymphocytes and natural killer cells. It plays a critical role in immune regulation, immune privilege, cancer, autoimmunity, and transplantation. The expression and function of FasL are tightly regulated to maintain Homeostasis, immune homeostasis. Structure Fas ligand operates as a type-II transmembrane protein through its membership in the tumor necrosis factor (TNF) superfamily. It operates under its official names FasL and CD95L or Apo-1L. With 281 amino acids the protein forms three identifiable structural components by including an intracellular N-terminal domain then follows with one transmembrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
