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Pyrrhocoricin
Pyrrhocoricin is a 20-residue long antimicrobial peptide of the firebug ''Pyrrhocoris apterus''. Structure and function Pyrrhocoricin is primarily active against Gram-negative bacteria. The peptide is proline-rich with proline-arginine repeats, as well a critical threonine residue, which is required for activity through ''O''-glycosylation. Like the antimicrobial peptides drosocin and abaecin, pyrrhocoricin binds to the bacterial protein DnaK, inhibiting cell machinery and replication. Only the L-enantiomer of pyrrhocoricin is active against bacteria. The action of pyrrhocoricin-like peptides is potentiated by the presence of pore-forming peptides, which facilitates the entry of pyrrhocoricin-like peptides into the bacterial cell. Proline-rich peptides like Pyrrhocoricin can also bind to microbe ribosomes, preventing protein translation In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosocin
Drosocin is a 19-residue long antimicrobial peptide (AMP) of flies first isolated in the fruit fly ''Drosophila melanogaster'', and later shown to be conserved throughout the genus ''Drosophila''. Drosocin is regulated by the NF-κB Imd signalling pathway in the fly. The ''Drosocin'' gene encodes two peptides: its namesake Drosocin peptide and a second peptide called Buletin. Structure and function Drosocin is primarily active against Gram-negative bacteria. The peptide is proline-rich with proline-arginine repeats, as well a critical threonine residue. This threonine is ''O''-glycosylated, which is required for antimicrobial activity. This ''O''-glycosylation can be performed either by mono- or disaccharides, which have different activity spectra. Like the antimicrobial peptides pyrrhocoricin and abaecin, drosocin binds to bacterial DnaK, inhibiting cell machinery and replication. The action of these drosocin-like peptides is potentiated by the presence of pore-forming pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimicrobial Peptide
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for antimicrobial peptides. These peptides are potent, broad spectrum antibiotics which demonstrate potential as novel therapeutic agents. Antimicrobial peptides have been demonstrated to kill Gram negative and Gram positive bacteria, enveloped viruses, fungi and even transformed or cancerous cells. Unlike the majority of conventional antibiotics it appears that antimicrobial peptides frequently destabilize biological membranes, can form transmembrane channels, and may also have the ability to enhance immunity by functioning as immunomodulators. Structure Antimicrobial peptides are a unique and diverse group of molecules, which are divided into subgroups on the basis of their amino acid composition and structure. Antimicrobial peptides are ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrrhocoris Apterus
The firebug, ''Pyrrhocoris apterus'', is a common insect of the family Pyrrhocoridae. Easily recognizable due to its striking red and black coloration, it may be confused with the similarly coloured though unrelated ''Corizus hyoscyami'' (cinnamon bug or squash bug). ''Pyrrhocoris apterus'' is distributed throughout the Palaearctic from the Atlantic coast of Europe to northwest China. It has also been reported from the United States, Central America, and India, and is also found in Australia. It has been reported as recently expanding its distribution northwards into mainland United Kingdom and eastward on to the coast of the Mediterranean Sea. They are frequently observed to form aggregations, especially as immature forms, containing from tens to perhaps a hundred individuals. Reproduction Firebugs generally mate in April and May. Their diet consists primarily of seeds from lime trees and mallows ( see below). They can often be found in groups near the base of lime tree tru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DnaK
The 70 kilodalton heat shock proteins (Hsp70s or DnaK) are a family of conserved ubiquitously expressed heat shock proteins. Proteins with similar structure exist in virtually all living organisms. Intracellularly localized Hsp70s are an important part of the cell's machinery for protein folding, performing chaperoning functions, and helping to protect cells from the adverse effects of physiological stresses. Additionally, membrane-bound Hsp70s have been identified as a potential target for cancer therapies and their extracellularly localized counterparts have been identified as having both membrane-bound and membrane-free structures. Discovery Members of the Hsp70 family are very strongly upregulated by heat stress and toxic chemicals, particularly heavy metals such as arsenic, cadmium, copper, mercury, etc. Heat shock was originally discovered by Ferruccio Ritossa in the 1960s when a lab worker accidentally boosted the incubation temperature of Drosophila (fruit flies). When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-enantiomer
In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical antipode – is one of two stereoisomers that are non-superposable onto their own mirror image. Enantiomers are much like one's right and left hands, when looking at the same face, they cannot be superposed onto each other. No amount of reorientation will allow the four unique groups on the chiral carbon (see Chirality (chemistry)) to line up exactly. The number of stereoisomers a molecule has can be determined by the number of chiral carbons it has. Stereoisomers include both enantiomers and diastereomers. Diastereomers, like enantiomers, share the same molecular formula and are non-superposable onto each other however, they are not mirror images of each other. A molecule with chirality rotates plane-polarized light. A mixture of equals amou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosomes
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA (rRNA) molecules and many ribosomal proteins (RPs or r-proteins). The ribosomes and associated molecules are also known as the ''translational apparatus''. Overview The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-cod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Translation
In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription of DNA to RNA in the cell's nucleus. The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is "read" by the ribosome. Translation proceeds in three phases: # Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon. # Elongation: The last tRNA validated by the small ribosomal subunit (''accommodati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect Immunity
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; In: potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans, which recent research has indicated insects are nested within. Nearly all insects hatch from eggs. Insect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
