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Amphibians defense

In addition to these well-characterized adaptive immune defenses, amphibians have an array of innate immune defenses. These include complement-mediated defenses [13], Natural Killer cells (NK) [14], phagocytic cells [15], and antimicrobial peptides secreted into the gut and skin mucosa [16, 17],... [Pg.386]

Defensive Compounds. The developmental stages of fireflies are poisonous due to the presence of steroidal pyrones called lucibufagins. Recently it became evident that exotic reptiles and amphibians from habitats without the poisonous fireflies, e.g. the Australian lizard Pogona, are killed immediately if they ingest just one firefly. [Pg.128]

Aquatic frogs and toads probably need less toxin for defense than terrestrial forms. The compounds in the frogs mucus are thought to be neuroleptic, blocking dopamine receptors. They also possibly are antibacterial and aid wound repair, and they are known to elevate the level of prolactin, the amphibian Juvenile hormone (Barthalmus and Zielinski, 1988). [Pg.254]

The prothoracic defensive secretion in one of water beetles, llybius fer-nestratus, contains as a main component methyl 8-hydroxyquinoline-2-carboxy-late (51) (Table V), which is not toxic to amphibians and fishes but produces clonic spasms in small mammals like mice (96,100,101). [Pg.204]

Based on their findings as well as those of others for ascidians, Lindquist et al.53 question the adequacy of the autotoxicity, energetic, or developmental constraints suggested by Orians and Janzen59 to explain a presumed lack of chemical defenses in the eggs and embryos of animals. Coupled with other reports of chemical defenses in the eggs and embryos of amphibians,66 insects,67 and additional marine invertebrates,44 43 52 54 68470 there appears to be ample evidence to question the validity of these presumed constraints. However, Slattery et al.70 recently suggested that the lack of chemical defenses in the larvae of the soft coral Sinularia polydactyla may be attributable to autotoxicity constraints. [Pg.201]

The pyrrolizidine oximes are unknown in Nature except in amphibians. There are, however, two closely related natural products, nitropoly-zonamine (the oxime of236 is replaced by a j3-nitro substituent in nitropo-lyzonamine) and its proposed bicyclic precursor polyzonimine, both of which were isolated from defensive secretions of the millipede Polyzonium rosalbum 154,155). Nitropolyzonamine, like the amphibian pyrrolizidine oximes, is dextrorotatory 155). Neither nitropolyzonamine nor polyzonimine has been detected in amphibians. [Pg.251]

Kats LB, Petranka JW, Sih A (1988) Antipredator defenses and the persistence of amphibian larvae. Ecology 69 1865-1870... [Pg.145]

Zasloff is quick to note that nobody has a clue how a giant squid or an octopus—which have neither antibodies nor white blood cells called lymphocytes—avoids becoming consumed by microbes Over the years, he and his colleagues have uncovered many frog-made peptides that possess potent microbe-killing properties. Such a chemical defense system operates by virtue of the peptides ability to poke holes in the cell membranes that serve to protect bacteria from the outside world. In addition to the peptides, scientists including Zasloff have found hundreds of other types of molecules called alkaloids in amphibian skin. When inside cells, many alkaloids home in on structures called ion channels—tunnel-like assemblies through which important electrolytes pass. These are key cellular fixtures,... [Pg.49]


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See also in sourсe #XX -- [ Pg.250 , Pg.259 ]




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