title: Evidence from peptidomic analysis of skin secretions that the red-legged frogs, Rana aurora draytonii and Rana aurora aurora, are distinct species.
abstract: The northern red-legged frog Rana aurora aurora and the California red-legged frog Rana aurora draytonii are traditionally classified together in the same species group. Ten peptides with antimicrobial activity were isolated from norepinephrine-stimulated skin secretions of R. aurora draytonii and purified to near homogeneity. The peptides were identified as belonging to the ranatuerin-2 family (two peptides), brevinin-1 family (four peptides), temporin family (three peptides), and a novel peptide, RV-23 (RIGVLLARLPKLFSLFKLMGKKV) that has limited structural similarity to the bee venom peptide, melittin. This distribution of peptides contrasts with that found previously in skin secretions from R. aurora aurora collected under the same conditions and at the same time of year (one ranatuerin-2 peptide, two brevinin-1 peptides, and one temporin peptide). The variation in amino acid sequences between corresponding R. aurora draytonii and R. aurora aurora peptides is comparable with the variation in sequences of orthologs from other members of the Amerana group of New World ranid frogs (Rana boylii, Rana muscosa, and Rana luteiventris). It is proposed, therefore, that the red-legged frogs should be regarded as separate species (R. aurora and R. draytonii) within the Amerana group rather than conspecific subspecies. The data emphasize that amino acid sequences of antimicrobial peptides in skin secretions may be used to infer taxonomic and phylogenetic relationships between species of ranid frogs.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al-Ain, United Arab Emirates. jmconlon@uaeu.ac.ae
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
authors.forename: Nadia
authors.initials: N
authors.lastname: Al-Ghafari
authors.forename: Laurent
authors.initials: L
authors.lastname: Coquet
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
authors.forename: Carlos
authors.initials: C
authors.lastname: Davidson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D010802:Phylogeny; D040901:Proteomics / Q000379:methods*; D011898:Ranidae; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*; D013045:Species Specificity; D013997:Time Factors
chemical_list: D023181:Antimicrobial Cationic Peptides; D010455:Peptides