Peptides toxic

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

Amino acid with antidysiipidemic and antihypergiycemic activities Amanitins - toxic peptides... 

H Fungi - Amanita phalloides and Agaricus phalloides Cyanobacteria -Lyngbya majuscula Phalloidin, phallicidin, and amanitin - toxic peptides Majusculamide D - cytotoxic peptide Microcolin A - peptide with immunosuppressive, antileukemic and protein kinase C inhibitory activity 242... 

As is clear from the preceding discussion, plants express a vast array of toxic peptides in their defense that are interesting as structural models, active compounds in crop protection, and active compounds in pharmaceutical applications. In the plant kingdom the defense mechanisms involved have produced peptides for many kinds of microorganisms and predators, and in future it is possible that for any new problem in bacterial, viral, or fungal infection, a solution can be found on the basis of leads from plant defense molecules. 

Other Peptide Toxin Producing Cyanobacteria. No other cyanobacteria genera have been analyzed for the presence of toxic peptides. Based on toxicity signs however it is thought that peptide toxins are present in certain isolates of Anabaena flos-aquae (J) and Oscillatorla agardhil (9,17). 

The cosmopolitan cyanobacterium Microcystis aeruginosa is frequently the major component of freshwater cyanobacterial blooms. These blooms can cause serious water management problems and are occasionally associated with animal poisoning. The aeruginosa toxins are potent lethal peptides which contain three invariant D-amino acids (Ala, erythro-3-methyl Asp, and Glu), two variant L-amino acids, N-methyl dehydroalanine, and a 3 amino acid (1-3). Multiple toxins have been purified from clonal isolates (1,4). The toxic peptide described in this chapter is denoted toxin-LR using the standard one-letter abbreviations for its two variant amino acids, leucine and arginine. 

Other parts of the northeastern Atlantic are more productive indole alkaloids isolated from bryozoans, seco-steroids from a gorgonian, Gersemia fruticosa, from the White Sea, toxic peptides from brackish-water cyanobacteria, and macrolides from dinoflagellates (Chart 7.8.A/P/PO). 

Amanita family of mushrooms which contains several toxic peptides helonging to the amatnxin and phalloioxin groups. 

One major recent development in the area of natural products is the discovery and subsequent medicinal application of the toxic peptides from cone snails. These Conus peptides, several of which contain a 6-bromotryptophan amino acid, are finding utility for the treatment of neuropathic pain and other neurological conditions (1074-1078). For example, oo-conopeptide MVIIA (Ziconotide, trade name Prialt) has been approved by the US FDA since 2004 for the treatment of severe pain. It is estimated that the 500-700 species of cone snails (Conus genus) contain... 

Four antimicrobial peptides, discodermins A-D (383-386), isolated from the Japanese sponge Discodermia kiiensis also show inhibitory activity on the development of starfish embryos (317,318). Three ichthyo-toxic peptides, pardaxins P-1 through P-3 (387-389), were isolated from... 

Chemical defenses are less commonly reported in other groups of mobile marine invertebrates, but they may exist. Heine et al.21 showed that a common Antarctic nemertean worm is rejected as prey by co-occurring fishes despite the lack of obvious structural defenses. The unpalatability has been attributed to a highly acidic mucus coating (pH 3.5), although toxic peptides were also present22... 

Onyewuenyi, N., and Hawkins, P. 1996. Separation of toxic peptides (microcystins) in capillary electrophoresis, with the aid of organic mobile phase modifiers. Journal of Chromatography A 749 271-278. 

Endothehns constitute a family of peptides (Hart and Hart, 1992). They are very potent endogenous vasoconstrictors and vasopressors and are secreted by various cells and tissues in the human body. Of the three isoforms, endothe-hn-1 (ET-1) is one of the most potent contractors of vascular smooth muscles (Miller et al, 1993). Endothelins have very similar structures and biological properties to sarafotoxins (Kloog and Sokolovsky, 1989), and the toxic peptides are obtained from the venom of mole vipers (Atractaspidae). 

Vogel J, Argaman L, Wagner EG, Almvia S. The small RNA IstR inhibits synthesis of an SOS-induced toxic peptide. Curr. Biol. 2004 14(24) 2271-2276. 

WielandT. The toxic peptides from Amanita mushrooms. Int J Pept Protein Res 1983 22 257-276 Karlson-Stiber C, Persson H. Cytotoxic fungi-an overview.Toxicon 2003 42 339-349... 

Experimental studies have shown that Leucinostatin A may be one of the several potentially toxic peptides produced by Acremonium sp. that contribute to the defense of the host. The host plant is relatively immune to Leucinostatin A, because it has an enzyme which transfers two glycosyl residues to leucinostatin A, thus reducing the peptide s bioactivity. From these results it can also be concluded that glucosylation reactions may play a general role in plant defenses, especially against toxin-mediated disease development [120]. 

Brooks, W.P. Codd, G.A. Extraction and purification of toxic peptides from natural blooms and laboratory isolate of the cyanobacterium Microcystis aeruginosa. Lett. Appl. Microbiol. 1986, 2, 1-7. 

Krishnamarty, T. Carmichael, W.W. Sarver, E.W. Investigations of freshwater cyanobacteria (blue-green algae) toxic peptides I. Isolation, purification and characterization of peptides from Microcystis aeruginosa and Ana-baena flos-aquae. Toxicon 1986, 24, 865-872. 

A plausible hypothesis at this stage (about 1943) was that a sequence occurred tryptophan —> an intermediate kynurenine kynurenic acid. It was thought that the intermediate between tryptophan and kynurenine might be the so-called a-hydroxytryptophan (for structure see p. 83), which had been obtained (917) on hydrolysis of phalloidine, a toxic peptide from the fungus Amanita pkalloides (567) such a pathway received... 

A large number of toxic peptides are found in cone snails (Conidae). They include four classes of small (13-29 amino acid) basic peptides, known as conotoxins, that have paralytic effects cu-conotoxins block presynaptic calcium channels, a-conotoxins bind to nicotinic ACh receptors in muscle, p-contoxins bind to muscle sodium channels, K-conotoxins may affect potassium channels. Other cone snail toxins include sleeper that induces sleep in mice, conopressin that produces scratching behaviour in mice and increases blood pressure in mammals and a larger (ca. 100 amino acid) toxin that produces convulsions in mice. 

Mastoparan. Wasps produce a wide variety of toxic peptides (202) that includes mastoparan, a 14-residue peptide isolated from the venom of Paravespula lewisii. Mastoparan stimulates the degranulation of mast cells,... 

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