01758naa a2200253 a 450000100080000000500110000800800410001910000230006024501040008326000090018752010650019665300330126165300250129470000170131970000240133670000180136070000170137870000180139570000190141370000170143270000200144970000210146977300140149011855172005-03-09       2005    bl ---       0--  u    #d1 aLEITE, J. R. S. A.  aPhylloseptinsba novel class of anti-bacterial and anti-protozoan peptides from Phyllomeduza genus.  c2005  aSix novel peptides called phylloseptins (PS-1, -2, -3, -4, -5, and -6) showing anti-bacterial (PS-1) and anti-protozoan (PS-4 and -5) activities were isolated from the skin secretion of the Brazilian tree-frogs, Phyllomedusa hypochondrialis and Phyllomedusa oreades. Phylloseptins have a primary structure consisting of 19?21 amino acid residues (1.7?2.1 kDa). They have common structural features, such as a highly conserved N-terminal region and C-terminal amidation. Phylloseptin-1 (FLSLIPHAINAVSAIAKHN-NH2) demonstrated a strong effect against Gram-positive and Gram-negative bacteria (MICs ranging from 3 to 7.9 µM), without showing significant hemolytic activity (&lt0.6% at the MIC range) towards mammalian cells. Atomic force microscopy experiments indicated that the bacteriolytic properties of these peptides might be related to their disruptive action on the cell membrane, characterized by a number of bubble-like formations, preceding every cell lysis. PS-4 and PS-5 showed anti-protozoan activity with IC50 at about 5 µM for Trypanossoma cruzi.  aPhyllomedusa hypochondrialis  aPhyllomedusa oreades1 aSILVA, L. P.1 aRODRIGUES, M. I. S.1 aPRATES, M. V.1 aBRAND, G. D.1 aLACAVA, B. M.1 aAZEVEDO, R. B.1 aBOCCA, A. L.1 aALBUQUERQUE, S.1 aBLOCH JUNIOR, C.  tPeptides.