Category: The Science
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Liver sinusoidal endothelial cells (LSECs) AKA the hepatic sinusoids
They form the lining of the smallest blood vessels in the liver
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Cleavage (embryology)
In embryology, cleavage is the division of cells in the early development of the embryo, following fertilization. The zygotes of many species undergo rapid cell cycles with no significant overall growth, producing a cluster of cells the same size as the original zygote. The different cells derived from cleavage are called blastomeres and form a compact mass called the morula. Cleavage ends with the formation of the blastula, or of the blastocyst in…
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Vitellin is essential in the fertilization process, and embryonic development in egg-laying organisms
Vitellin is a protein found in the egg yolk. It is a phosphoprotein. Vitellin is a generic name for major of many yolk proteins. Vitellin has been known since the 1900s. The periodic acid-Schiff method and Sudan black B dye was used to help determine that Vitellin is a glycolipoprotein because it stained positive when tested. This protein was…
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Protein phosphorylation was first reported in 1906
Protein phosphorylation is a reversible post-translational modification of proteins in which an amino acid residue is phosphorylated by a protein kinase by the addition of a covalently bound phosphate group. Phosphorylation alters the structural conformation of a protein, causing it to become activated, deactivated, or otherwise modifying its function. Approximately 13,000 human proteins have sites that are phosphorylated. The reverse reaction of phosphorylation is called dephosphorylation, and is catalyzed by…
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Phosphorylation
In biochemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion.[1] This process and its inverse, dephosphorylation, are common in biology.[2] Protein phosphorylation often activates (or deactivates) many enzymes.[3][4] During respiration and photosynthesis Phosphorylation is essential to the processes of both anaerobic and aerobic respiration, which involve the production of adenosine triphosphate (ATP), the “high-energy” exchange medium in the cell. During aerobic respiration, ATP is synthesized…
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Human cells contain a DNA-activated protein kinase that phosphorylates simian virus 40 T antigen, mouse p53, and the human Ku autoantigen
Abstract HeLa cells contain a serine/threonine protein kinase (DNA-PK) that is strongly activated in vitro by low concentrations of double-stranded DNA (dsDNA). Activation was specific for dsDNA; both natural DNAs and synthetic oligonucleotides functioned as kinase activators. The fact that DNA-PK activity was rapidly inhibited by incubation with dsDNA and ATP suggests that DNA-PK activity…
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Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA. NHEJ is active in both non-dividing and proliferating cells.
Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA. It is called “non-homologous” because the break ends are directly ligated without the need for a homologous template, in contrast to homology directed repair (HDR), which requires a homologous sequence to guide repair. NHEJ is active in both non-dividing and proliferating cells, while HDR is not readily…
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Ku is a dimeric protein complex that binds to DNA double-strand break ends and is required for the non-homologous end joining (NHEJ) pathway of DNA repair
Ku is evolutionarily conserved from bacteria to humans. The ancestral bacterial Ku is a homodimer (two copies of the same protein bound to each other).[2] Eukaryotic Ku is a heterodimer of two polypeptides, Ku70 (XRCC6) and Ku80 (XRCC5), so named because the molecular weight of the human Ku proteins is around 70 kDa and 80 kDa. The two Ku subunits form a basket-shaped structure that threads onto…
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The trefoil knot fold is a protein fold in which the protein backbone is twisted into a trefoil knot shape
“Shallow” knots in which the tail of the polypeptide chain only passes through a loop by a few residues are uncommon, but “deep” knots in which many residues are passed through the loop are extremely rare. Deep trefoil knots have been found in the SPOUT superfamily. including methyltransferase proteins involved in posttranscriptional RNA modification in all three domains of life, including bacterium Thermus thermophilus and…
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Cyanamide notes (it was a polio vaccine that spurred these notes and by now polio has five mentions on the page and these are two of them)
I’m going to add some polio vaccine stuff at the top of these notes. Hilary Koprowski is the one mentioned on the Polio Hall of Fame page who was not included in the hideous monument, see What In God’s Name, even though he (and his work) have direct connection to those who are included. He…
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Aliivibrio fischeri (aka Vibrio fischeri), a bioluminescent bacteria and a glowing squid
Aliivibrio fischeri (also called Vibrio fischeri) is a Gram-negative, rod-shaped bacterium found globally in marine environments. This species has bioluminescent properties, and is found predominantly in symbiosis with various marine animals, such as the Hawaiian bobtail squid. It is heterotrophic, oxidase-positive, and motile by means of a single polar flagella. Free-living A. fischeri cells survive on decaying organic matter. The bacterium is a key research organism for examination of microbial bioluminescence, quorum sensing, and bacterial-animal symbiosis. It is named…
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Tracheal cytotoxin (TCT) is a soluble piece of peptidoglycan (PGN) found in the cell wall of all gram-negative bacteria, but only some bacteria species release TCT including Bordetella pertussis, Vibrio fischeri, and Neisseria gonorrhoeae
Tracheal cytotoxin (TCT) is a 921 dalton glycopeptide released by Bordetella pertussis, Vibrio fischeri (as a symbiosis chemical), and Neisseria gonorrhoeae (among other peptidoglycan-derived cytotoxins it produces). It is a soluble piece of peptidoglycan (PGN) found in the cell wall of all gram-negative bacteria, but only some bacteria species release TCT due to inability to recycle this piece of anhydromuropeptide. History In 1980, it was discovered that B. pertussis could attach to hamster tracheal epithelial (HTE) cells, and also, that…
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Fibroin is an insoluble protein present in silk produced by numerous insects
Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of Bombyx mori, and other moth genera such as Antheraea, Cricula, Samia and Gonometa. Silk in its raw state consists of two main proteins, sericin and fibroin, with a glue-like layer of sericin coating two singular filaments of fibroin called brins. BRIN AND BAVE (BRIN) One of the radiating sticks of a fan.…
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Sericin is a protein created by Bombyx mori (silkworms) in the production of silk
Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% fibroin and 20–30% sericin; fibroin being the structural center of the silk, and sericin being the gum coating the fibres and allowing them to stick to each other. Structure Sericin is composed…
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Riboflavin and its breakdown products interact with DNA, making this system attractive in the photodisinfection of blood and blood products
The application of photosensitisers to tropical pathogens in the blood supply Mark Wainwright PhD, Mauricio S. Baptista, in Photodiagnosis and Photodynamic Therapy, 2011 Riboflavin As vitamin B2, riboflavin (Fig. 5) is an essential nutrient in humans. The Mirasol system (Navigant Biotechnologies Inc., CO, USA) utilises riboflavin as a photosensitiser in conjunction with long-wave ultraviolet light [37]. Plainly given its essential nature, there are fewer potential toxicity problems…
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Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane
Not to be confused with glycopeptide, proteoglycan, or glycoprotein Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane, the rigid cell wall (murein sacculus) characteristic of most bacteria (domain Bacteria). The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is an oligopeptide chain made of three to five amino acids.…
