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Kassinin
Kassinin is a peptide derived from the Kassina frog. It belongs to tachykinin family of neuropeptides. It is secreted as a defense response, and is involved in neuropeptide signalling. The amino acid sequence is H-Asp-Val-Pro-Lys-Ser-Asp-Gln-Phe-Val-Gly-Leu-Met-NH2 (DVPKSDQFVGLM-NH2). Ion transportation In frog skin, tachykinins are responsible for ion transportation. Kassinin is one of the tachykinin peptides, which interacts with NK2 receptor to increase short circuit current (SCC), resulting in an ion transportation in frog skin. Another peptide that belongs to tachykinin family is Eledoisin that interacts with NK3 receptor for stimulation of SCC, but can be reduced by either NK1 or NK2 antagonist, whereas kassinin can't be reduced by either of these NK1, NK2 or NK3 antagonists. Kassinin is very effective in increasing short circuit current to its maximum within 10 minutes with increase of 26.13 ± 1.53 μΑ/cm2. There are some requirements that must be accomplished to ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kassina
''Kassina'' is a genus of hyperoliidae, hyperoliid frogs, commonly referred to as running frogs or kassinas. They are found throughout sub-Saharan Africa. They are characterized by preferring a distinctive "walking" with the back legs instead of the more traditional frog-hopping. Species The following species are recognized in the genus ''Kassina'': In captivity ''K. maculata'' is frequently exported from Tanzania for the exotic pet trade. They require more horizontal space than vertical, being a terrestrial species. Their captive environment should include a substrate that accommodates burrowing, and provides high humidity. ''K. maculata'' will readily eat crickets and small mealworms, although insects should be dusted with a vitamin supplement. Other species of running frogs are occasionally imported, with the ''K. senegalensis'' being the next most common species in captivity. Research It is the source of "kassinin", a frequently studied tachykinin peptides, tachykinin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachykinin Family
Tachykinin peptides are one of the largest families of neuropeptides, found from amphibians to mammals. They were so named due to their ability to rapidly induce contraction of gut tissue. The tachykinin family is characterized by a common C-terminal sequence, Phe-X- Gly- Leu- Met-NH2, where X is either an Aromatic or an Aliphatic amino acid. The genes that produce tachykinins encode precursor proteins called preprotachykinins, which are chopped apart into smaller peptides by posttranslational proteolytic processing. The genes also code for multiple splice forms that are made up of different sets of peptides. Tachykinins excite neurons, evoke behavioral responses, are potent vasodilators, and contract (directly or indirectly) many smooth muscles. Tachykinins are from ten to twelve residues long. The two human tachykinin genes are called TAC1 and TAC3 for historical reasons, and are equivalent to Tac1 and Tac2 of the mouse, respectively. TAC1 encodes neurokinin A (formerly known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic peptides have an N-terminal (amine group) and C-terminal (carboxyl g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frog
A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough skin texture due to wart-like parotoid glands tend to be called toads, but the distinction between frogs and toads is informal and purely cosmetic, not from taxonomy (biology), taxonomy or evolutionary history. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest and associated wetlands. They account for around 88% of extant amphibian species, and are one of the five most diverse vertebrate orders. The oldest fossil "proto-frog" ''Triadobatrachus'' is known from the Early Triassic of Madagascar (250Myr, million years ago), but molecular clock, molecular clock dating suggests their divergent evolution, divergence from other amphibians may exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuropeptides
Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the gut, muscles, and heart. Neuropeptides are synthesized from large precursor proteins which are cleaved and post-translationally processed then packaged into large dense core vesicles. Neuropeptides are often co-released with other neuropeptides and neurotransmitters in a single neuron, yielding a multitude of effects. Once released, neuropeptides can diffuse widely to affect a broad range of targets. Neuropeptides are extremely ancient and highly diverse chemical messengers. Placozoa, Placozoans such as ''Trichoplax'', extremely basal animals which do not possess neurons, use peptides for cell-to-cell communication in a way similar to the neuropeptides of higher animals. Examples Peptide signals play a role in information processing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 appear in the genetic code of life. Amino acids can be classified according to the locations of the core structural functional groups ( alpha- , beta- , gamma- amino acids, etc.); other categories relate to polarity, ionization, and side-chain group type ( aliphatic, acyclic, aromatic, polar, etc.). In the form of proteins, amino-acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence. Amino acids are formally named by the IUPAC- IUBMB Joint Commi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eledoisin
Eledoisin is an undecapeptide of mollusk origin, belonging to the tachykinin family of neuropeptides. It was first isolated from the posterior salivary glands of two mollusk species '' Eledone muschata'' and ''Eledone aldovandi'', which belong to the octopod order of Cephalopoda.De Marco, A., and G. Gatti, "1H- and 13C-NMR spectra of eledoisin and intermediate oligopeptides." ''Int. J. Pep. Pro. Res.'' 7:437–444, 1975. Other tachykinins from nonmammalian sources include kassinin and physalaemin. The mammalian tachykinins substance P, NKA, and NKB have similar effects as tachykinins of nonmammals and have been more widely studied and characterized. These peptides exhibit a wide and complex spectrum of pharmacological and physiological activities such as vasodilation, hypertension, and stimulation of extravascular smooth muscle.R. Christy Rani Grace, Indu R. Chandrashekar and Sudha M. Cowsik"Solution Structure of the Tachykinin Peptide Eledoisin", ''Biophysical Journal'' 84:65 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substance P
Substance P (SP) is an undecapeptide (a peptide composed of a chain of 11 amino acid residues) and a type of neuropeptide, belonging to the tachykinin family of neuropeptides. It acts as a neurotransmitter and a neuromodulator. Substance P and the closely related neurokinin A (NKA) are produced from a polyprotein precursor after alternative splicing of the preprotachykinin A gene. The deduced amino acid sequence of substance P is as follows: * Arg Pro Lys Pro Gln Gln Phe Phe Gly Leu Met (RPKPQQFFGLM) with an amide group at the C-terminus. Substance P is released from the terminals of specific sensory nerves. It is found in the brain and spinal cord and is associated with inflammatory processes and pain. Discovery The original discovery of Substance P (SP) was in 1931 by Ulf von Euler and John H. Gaddum as a tissue extract that caused intestinal contraction ''in vitro''. Its tissue distribution and biologic actions were further investigated over the follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposome
The exposome is a concept used to describe environmental exposures that an individual encounters throughout life, and how these exposures impact biology and health. It encompasses both external and internal factors, including chemical, physical, biological, and social factors that may influence human health. The study of the exposome has become a useful tool in understanding the interplay between genetics and environmental factors in the development of diseases, with a particular focus on chronic conditions. The concept has been widely applied in fields such as epidemiology, toxicology, and public health, among others, and has led to significant advances in our understanding of disease etiology and prevention. By considering the cumulative effect of multiple exposures, it provides a holistic approach to the study of gene-environment interactions, allowing for a more accurate assessment of disease risk and the identification of potential intervention strategies. Environmental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
