The protein, peptide and free amino-acid contents of some species of Gracilaria from south-east coast of India

Four species of Gracilaria are investigated for their free amino-acid contents, as well as amino-acid constituents in the proteins and the peptides, using quantitative paper chromatographic technique. Amino-acid constituents of different species of Gracilaria differ only in amount, while free amino-acids and the amino-acids in the peptides vary both in quality and quantity. A number of amino-acids recorded as protein constituents have even escaped detection in the peptides, while in the free state they occur either in all the species or in some only except homocystine. Moreover, some amino-acids occur exclusively in the free state.

A novel bradykinin-related peptide from skin secretions of toad Bombina maxima and its precursor containing six identical copies of the final product

Amphibian skin contains rich bradykinin-related peptides, but the mode of biosynthesis of these peptides is unknown. In the present study, a novel bradykinin-related peptide, termed bombinakinin M, was purified from skin secretions of the Chinese red bell

An anionic antimicrobial peptide from toad Bombina maxima

Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide. named maximin H5. was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2,. Containing three aspartate residues and no basic amino acid residues. maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides. only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5. while the other bacteria] and fungal strains tested ere resistant to it. The presence of metal ions. like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians, The results provide the first evidence that. together kith cationic antimicrobial peptides. anionic antimicrobial peptides may also exist naturally as part of the innate defense system. (C), 2002 Elsevier Science (USA). All rights reserved.

A novel proline rich bombesin-related peptide (PR-bombesin) from toad Bombina maxima

A novel bombesin-related peptide was isolated from skin secretions of Chinese red belly toad Bombina maxima. Its primary structure was established as pGlu-Lys-Lys-Pro-Pro-Arg-Pro-Pro-Gln-Trp-Ala-Val-Gly-His-Phe-Met-NH2. The amino-terminal (N-terminal) 8-residue segment comprising four prolines and three basic residues is extensively different from bombesins from other Bombina species. The peptide was thus named proline rich bombesin (PR-bombesin). PR-bumbesin was found to elicit concentration-dependent contractile effects in the rat stomach strip, with both increased potency and intrinsic activity as compared with those of [Leu(13)]bombesin. Analysis of different bombesin cDNA structures revealed that an 8 to 14- nucleotide fragment replacement in the peptide coding region (TGGGGAAT in the cDNAs of multiple bombesin forms from Bombina orientalis and CACCCCGGCCACCC in the cDNA of PR-bombesin) resulted in an unusual Pro-Pro-Arg-Pro-Pro motif in the N-terminal part of PR-bombesin. (C) 2002 Elsevier Science Inc. All rights reserved.

An opioid peptide from synganglia of the tick, Amblyomma testindinarium

An opioid peptide, which shares similarity with mammalian hemorphins, has been identified from the synganglia (central nervous system) of the hard tick, Amblyomma testindiarium. Its primary sequence was established as LVVYPWTKM that contains a tetrapeptide sequence Tyr-Pro-Trp-Thr of hemorphin-like opioid peptides. By hot-plate bioassay, the purified peptide and synthetic peptide displayed dose-related antinociceptive effect in mice, as observed for other hemorphin-like opioid peptides. This is the first opioid peptide identified from ticks. Ticks may utilize the opioid peptide in their strategy to escape host immuno-surveillance as well as in inhibiting responses directed against themselves. (c) 2004 Elsevier Inc. All rights reserved.

A novel antimicrobial peptide from salivary glands of the hard tick, Ixodes sinensis

A novel antimicrobial peptide named as ixosin was isolated from the salivary glands of the hard tick, Ixodes sinensis, by gel filtration, ion exchange chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). Its amino acid sequen

A novel algesic peptide derived from skin secretions of the frog Amolops loloensis

Several algesic agents including bradykinin and tachykinin have been identified from skin secretions of amphibians. They may act in defensive roles against aggressors. In this study, a novel peptide named Amolos with an amino acid sequence of FLPIVGAKL an

Bombinakinin M gene associated peptide, a novel bioactive peptide from skin secretions of the toad Bombina maxima

A novel 28-amino acid peptide, termed bombinakinin-GAP, was purified and characterized from skin secretions of the toad Bombina maxima. Its primary structure was established as DMYEIKQYKTAHGRPPICAPGEQCPIWV-NH2, in which two cysteines form a disulfide bond. A FASTA search of SWISS-PROT databank detected a 32% sequence identity between the sequences of the peptide and a segment of rat cocaine- and amphetamine-regulated transcript (CART). Intracerebroventricular (i.c.v.) administration of the peptide induced a significant decrease in food intake in rats, suggesting that it played a role in the control of feeding by brain. Analysis of its cDNA structure revealed that this peptide is coexpressed with bombinakinin M, a bradykinin-related peptide from the same toad. Bombinakinin-GAP appears to be the first example of a novel class of bioactive peptides from amphibian skin, which may be implicated in feeding behavior. (C) 2003 Elsevier Science Inc. All rights reserved.

An antimicrobial peptide with antimicrobial activity against Helicobacter pylori

An antimicrobial peptide named odorranain-HP was identified from skin secretions of the diskless odorous frog, Odorrana grahami. It is composed of 23 amino acids with an amino acid sequence of GLLRASSVWGRKYYVDLAGCAKA. By BLAST search, odorranain-HP had si

Vespid chemotactic peptide precursor from the wasp, Vespa magnifica (Smith)

Despite the evolutional distance between wasp and amphibian, vespid chemotactic peptide (VCP), an important component of wasp venom, are found sharing remarkable similarities with the temporin antimicrobial peptides (AMPs) from Ranid frog, Amolops loloens