Occurence of an eledoisin-like polypeptide (physalaemin) in skin extracts of Physalaemus fuscumaculatus

152 Caner, A. B. (Amer. University, Washington, D.C ., and Woods Hole, Mass .) : A toxin in the ccelomic fluid of scalded starfish (Asterias. /orbesi) . Proc. Soc. exp. Biol N. Y., 109, 791, 1962 . ACCORDING to the toxic-factor theory of burns, the circulating fluid of a scalded animal should contain a toxin or toxins partly responsible for the death of the animal . It was found that ccelomic fluid from scalded starfish (Asterias forbesi) is capable of inducing the reaction of autotomy in normal starfish, whereas ccelomic fluid from non-scalded starfish has no apparent effect under otherwise identical conditions and demonstrates the presence of a factor, possible a toxin, in the body fluid of starfish as a result of the scalding . There was evidence of a lack of species specificity exhibited by the toxin taken from the ccelomic fluid of scalded starfish, which proved lethal when injected into various other species, with the exception of Heuriciar ,canguinoleuta. B.W.H. CLEGG, J. B. and Bntt .EV, K . (Dept. of Biochem. University of Cambridge, England) : The separation and isolation of the peptide chains of fibrin . Biochim. biophyc. Acta, 63, 525, 1962. Tae disulphide bonds of bovine fibrinogen, thrombin-fibrin and Reptilase-fibrin, the last formed by clotting fibrinogen with an enzyme preparation from Bothrops jararaca venom, were cleaved by sulphite and the resulting S-sulphonated proteins examined by starch-gel electrophoresis in 8 M urea at different pH . S-sulpho-fibrinogen and S-sulpho-thrombin-fibrin showed t~NO bands, where as S-sulpho-Reptilase-fibrin showed three, corresponding to three fractions separated by chromatography on CM-cellulose. The first band, common to all three preparations, was due to the peptide chain (T-chain) of fibrinogen with N-terminal tyrosine and not attacked by either thrombin or Reptilase. The second band, formed by S-sulpho-Reptilasefibrin, corresponded to the B-chain of fibrinogen which was attacked by thrombin but not by Reptilase. The third band corresponded to the A-chain of fibrinogen from which a peptide had bcen released by Reptilase giving rise to N-terminal glycine. Thrombin also attacked this chain, but only with Reptilase, which left the B~hain unchanged and caused the A-chain to loose four negative charges were the two resolved into separate bands. Further experiments with S-sulpho-fibrinogen, S-sulpho-Reptilase-fibrin and thrombin indicated that neither the intact three-dimensional structure of fibrinogen nor the presence of T~hain is necessary for thrombin specificity, the clue to which is more likely to be found in the stnrctures of the A and B chains . P.A .C . ERSPAMER, V., BERTACCINI, G. and Cet, J. M. (Instituto di Farmacologia, University di Parma, Italy) : Occurrence of bradykinin-like substances in the amphibian skin . Expericntia 18, 563, 7 962. METHAriOL extraCÍS Of the skin of Phyllomedusa were dissolved in 95 ~ ethanol and absorbed on an alkaline alumina cohunn . Elution was carried out with ethanol. At least three peaks of activity appeared in the eluates : polypeptide A, which was bradykinin-like in its pharmacological activities ; polypeptide B, which possessed a potent hypotensive effect, and polypeptide C, which was particularly active on guinea-pig ileum. Polypeptides identical or similar to polypeptide A have been found in Phyllomedusa rhodei, Rana escrrlertta and Rana temporaria. H.M . ERSPAMER, V., BERTACCINI, G. and CEt, J. M. (Instituto di Farmacologia, University di Parrna, Italy) : Occurencee of an eledoisin-like polypeptide (physalaemin) in skin extracts of Phvsalaenruc fuscunraculatus . Experientia, 18, 562, 1962 . AcerorvE and methonal extracts of the dry and wet skin of Physalaernus juscumaculatus, a South American amphibian, contain a substance that markedly lowers systemic blood pressure in dogs and rabbits, and exerts a potent stimulative effect on some extravascular smooth muscles. The fall in blood pressure is of short duration and may be produced in the dog by the intravenous injection of an extract corresponding to 5 tag fresh skin/kg body weight. Physalaemin may be distinguished from other known biogenic polypeptides, including eledoisin. Eledoisin is the active endecapeptide isolated by Erspamer and Anastasi (Experientia, IS, 58, 1962) from the posterior salivary gland of the eight-armed Mediterranean cephalopod Eledone. V.E .