Evidence from peptidomic analysis of skin secretions that allopatric populations of Xenopus gilli (Anura:Pipidae) constitute distinct lineages

Abstract

The International Union for Conservation of Nature (IUCN) Endangered Cape Platanna Xenopus gilli inhabits disjunct ranges at the tip of Cape Peninsula and near the town of Kleinmond on opposite sides of False Bay in the extreme southwest of Africa. Peptidomic analysis of host-defense peptides in norepinephrine-stimulated skin secretions from frogs from the Cape Peninsula range resulted in the identification of two magainins, two peptide glycine-leucine-amide (PGLa) peptides, two xenopsin-precursor fragment (XPF) peptides, nine caerulein-precursor fragment (CPF) peptides, and a peptide related to peptide glycine-glutamine (PGQ) previously found in an extract of Xenopus laevis stomach. The primary structures of the peptides indicate a close phylogenetic relationship between X. gilli and X. laevis but only magainin-1, PGLa and one CPF peptide are identical in both species. Consistent with previous data, the CPF peptides show the greatest antimicrobial potency but are hemolytic. There are appreciable differences in the expression of host-defense peptide genes in frogs from the population of animals sampled near Kleinmond as peptides corresponding to magainin-G2, XPF-G1, XPF-G2, and four CPF peptides, present in secretions from the Cape Peninsula frogs, were not identified in the skin secretions from Kleinmond frogs. Conversely, PGLa-G3, XPF-G3, and three CPF peptides were identified in the Kleinmond frogs but not in the Cape Peninsula animals. The data support the conclusion from morphometric analyses and comparisons of the nucleotide sequences of mitochondrial genes that the disjunct populations of X. gilli have undergone appreciable genetic, morphological, and phenotypic divergence.

Limited genomic consequences of hybridization between two African clawed frogs, Xenopus gilli and X. laevis (Anura: Pipidae)

“…Analysis of mtDNA 26, 27, 45 and skin peptides secreted by these populations 76 support the existence of at least two distinct populations in X . gilli in the western and eastern portion of its range.…”

Host-defense and trefoil factor family peptides in skin secretions of the Mawa clawed frog Xenopus boumbaensis (Pipidae)

“…The primary structures of the peptides from which the trees are derived are shown in [6,7,30]. Evolutionary distances were computed using the Dayhoff matrix-based substitution model [33] and are in the units of the number of amino acid substitutions per site.…”

“…The Cape Platanna X. gilli inhabits disjunct ranges on opposite sides of False Bay in the extreme southwest of Africa. Even though these ranges are only 100 km apart, evidence from peptidomic analysis of skin secretions indicates that populations have undergone appreciable phenotypic divergence and are now regarded as separate sub-species [7]. In humans, the TFF family (formerly termed P-domain family peptides) includes three members: TFF1 also called pS2, TFF2 or spasmolytic polypeptide, and TFF3 or intestinal trefoil factor (ITF).…”

“…[6,7,30]). Similarly, an extensive family of hostdefense peptides, termed the hymenochirins, with antimicrobial, anticancer and immunomodulatory properties have been identified in skin secretions of the Congo dwarf clawed frog Hymenochirus boettgeri [3,31,32] and Merlin's clawed Pseudhymenochirus merlini [10,29,34].…”

Análise proteômica comparativa das secreções das glândulas parotoides e mucosas do sapo Rhinella schneideri e avaliação, in vitro, da atividade antimicrobiana

“…As secreções de anfíbios são complexos proteomas, contendo inúmeros componentes proteicos de famílias "distintas" (WANG et al, 2012 (CONLON, et al, 2007a;CONLON, et al, 2007b;CONLON et al, 2015;GENG et al, 2015;HU et al, 2014;KING et al, 2013;RATES et al, 2011;THOMPSON et al, 2007;WU et al, 2011 CONLON, et al, 2007b Capítulo II: Objetivos 65…”