![]() ![]() wittei is more closely related to the Xenopus amieti-Xenopus andrei group suggesting a common tetraploid ancestor. vestitus and Xenopus lenduensis, suggestive of bifurcating speciation after allopolyploidization, whereas X. The data support a sister-group relationship between X. The primary structures of the peptides provide insight into phylogenetic relationships among the octoploid Xenopus frogs. The variability in the numbers of paralogs in each peptide family indicates a selective silencing of the host-defense peptide genes following the polyploidization events. wittei secretions contains the novel peptide xenopsin. In addition, secretions from both species contain caerulein, identical to the peptide from Xenopus laevis, but X. wittei peptides comprise magainin (4 peptides), PGLa (1 peptide), XPF (2 peptides), and CPF (7 peptides). vestitus peptides belong to the magainin (3 peptides), peptide glycine-leucine-amide (PGLa 4 peptides), xenopsin-precursor fragment (XPF 1 peptide), and caerulein-precursor fragment (CPF 5 peptides) families. Structural characterization demonstrated that the X. Peptidomic analysis was used to compare the diversity of host-defense peptides in norepinephrine-stimulated skin secretions from the octoploid frogs, Xenopus vestitus (Kivu clawed frog) and Xenopus wittei (De Witte's clawed frog) in the family Pipidae. However, the very low antimicrobial activity of the magainin-AM1 and PGLa-AM2 paralogs suggests the possibility that certain peptides may have evolved toward a new, as yet undetermined, function (neofunctionalization).The primary structures of host-defense peptides have proved useful in elucidating the evolution history of frogs. ![]() The data indicate that nonfunctionalization has been the most common fate of duplicated antimicrobial peptide genes following the polyploidization events in the X. CFP-AM1 (GLGSVLGKALKIGANLL.NH2) was the most potent peptide present in the secretions and magainin-AM2 (GVSKILHSAGKFGKAFLGEIMKS) was the most abundant. Two peptides (magainin-AM1 and -AM2) are othologous to the magainins, two peptides (PGLa-AM1 and -AM2) orthologous to peptide glycine–leucine-amide, four peptides (CPF-AM1, -AM2, -AM3, -AM4) orthologous to caerulein-precursor fragments, and one peptide (XPF-AM1) structurally similar to xenopsin-precursor fragments were characterized. laevis (2n = 36) and the diploid frog Silurana (formerly Xenopus) tropicalis (2n = 20). amieti that showed structural similarity to peptides previously isolated from the tetraploid frog X. Nine peptides with differential antimicrobial activity against Escherichia coli and Staphylococcus aureus were isolated from norepinephrine-stimulated skin secretions of X. The Volcano clawed frog Xenopus amieti Kobel, du Pasquier, Fischberg, and Gloor, 1980, with a chromosome number of 2n = 72, is believed to have undergone two rounds of genome duplication since evolving from a diploid ancestor. aureus (MRSA) and multidrug-resistant Acinetobacter baumannii (MDRAB) with MIC values in the range 4–8 μM. CPF-B1 was active against clinical isolates of the nosocomial pathogens, methicillin-resistant S. This peptide was also the most abundant antimicrobial peptide in the skin secretions. aureus, and MIC = 25 μM against Candida albicans, and low hemolytic activity against human erythrocytes (LC50 > 200 μM). The peptide with the greatest potential for development into a therapeutically valuable anti-infective agent was CPF-B1 (GLGSLLGKAFKIGLKTVGKMMGGAPREQ) with MIC = 5 μM against E. In addition, a second magainin-related peptide (G**KFLHSAGKFGKAFLGEVMIG) containing a two amino acid residue deletion compared with magainin-2 was identified that had only weak antimicrobial activity. Structural characterization of the peptides demonstrated that they were orthologous to magainin-2 (1 peptide), peptide glycine–leucine-amide, PGLa (2 peptides), caerulein-precursor fragments, CPF (4 peptides), and xenopsin-precursor fragments, XPF (2 peptides), previously isolated from Xenopus laevis and X. ![]() Nine peptides with differential growth inhibitory activity against Escherichia coli and Staphylococcus aureus were isolated from norepinephrine-stimulated skin secretions of the tetraploid frog Xenopus borealis Parker, 1936 (Pipidae). ![]()
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