Bradykinin-related peptides and tryptophyllins in the skin secretions of the most primitive extant frog, Ascaphus truei

Conlon, J. Michael; Jouenne, Thierry; Cosette, Pascal; Cosquer, David; Vaudry, Hubert; Taylor, Christopher K.; Abel, Peter W.

doi:10.1016/j.ygcen.2005.04.006

Cited by 36 publications

(26 citation statements)

References 35 publications

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“…However, general gland morphology shows the same features as in other anurans, namely, a secretory unit containing storage granules ensheathed by contractile myoepithelial cells. We further demonstrate that the peptides produced in the granular glands of native Leiopelma species do not show any sequence homology to other amphibian peptides, including those from other archaic frogs such as Bombina (Mignogna et al, 1996) and Ascaphus species (Conlon et al, 2004;Conlon et al, 2005).…”

Section: Discussionmentioning

confidence: 69%

Differential polymorphism in cutaneous glands of archaic Leiopelma species

Melzer

Clerens

Bishop

2011

Journal of Morphology

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Endemic New Zealand frogs of the genus Leiopelma are from a basal lineage of extant anurans that release defensive secretions onto their skin when disturbed. Here, we characterize the gross anatomy and microscopic structure of the skin of L. archeyi, L. hochstetteri, and L. pakeka using stereoscopic, light and transmission electron microscopy. The terrestrial L. archeyi and L. pakeka possess dimorphic granular glands, categorized as type I and II, based on their frequency and morphological traits, whereas the semi-aquatic L. hochstetteri lacks type I glands. This is the first report of differential dimorphism in anurans of the same genus. This dimorphism could be interpreted as an adaptation to different physiological or ecological needs of these species. However, species within this ancient genus share similar general gland morphology with other anurans, namely, a secretory unit containing storage granules ensheathed by myoepithelial cells. Type I glands are ellipsoid, large and contain a homogeneous mass of electron-dense granules (1.8 ± 0.08 μm in diameter). Type II glands are round and contain larger heterogeneous granules (4.06 ± 0.16 μm) of varying densities. Exposure to noradrenaline causes the contraction of myoepithelial cells, resulting in bulk discharge of type I glands through the epidermal duct onto the skin surface. Differential release of secretions from dimorphic glands may be indicative of their functional specialisation in antipredatory or regulative roles. Mass spectrometric techniques were used to de novo sequence peptides present in the skin secretions of Leiopelma species. A total of 30 previously undescribed peptides from Leiopelma species were fully or partially sequenced. These peptides exhibited no similarity to any known compounds.

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Section: Discussionmentioning

confidence: 69%

Differential polymorphism in cutaneous glands of archaic Leiopelma species

Melzer

Clerens

Bishop

2011

Journal of Morphology

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“…[3–78–1112–13] What has become clear is that such amphibian secretions represent a unique resource for the discovery of natural structural variants of the canonical mammalian peptide and that many of these are homologs of forms found in submammalian vertebrates. [910] The wide range of variants is thought to be due to molecular tailoring of core structures through natural selection to provide the most effective spectrum of agents to deter predation by specific predator groups.…”

Section: Discussionmentioning

confidence: 99%

Peptide IC-20, encoded by skin kininogen-1 of the European yellow-bellied toad, Bombina variegata, antagonizes bradykinin-induced arterial smooth muscle relaxation

Yang

Bai

et al. 2011

J Pharm Bioall Sci

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Objectives:The objectives were to determine if the skin secretion of the European yellow-bellied toad (Bombina variegata), in common with other related species, contains a bradykinin inhibitor peptide and to isolate and structurally characterize this peptide.Materials and Methods:Lyophilized skin secretion obtained from this toad was subjected to reverse phase HPLC fractionation with subsequent bioassay of fractions for antagonism of the bradykinin activity using an isolated rat tail artery smooth muscle preparation. Subsequently, the primary structure of the peptide was established by a combination of microsequencing, mass spectroscopy, and molecular cloning, following which a synthetic replicate was chemically synthesised for bioassay.Results:A single peptide of molecular mass 2300.92 Da was resolved in HPLC fractions of skin secretion and its primary structure determined as IYNAIWP-KH-NK-KPGLL-. Database interrogation with this sequence indicated that this peptide was encoded by skin kininogen-1 previously cloned from B. variegata. The blank cycles were occupied by cysteinyl (C) residues and the peptide was located toward the C-terminus of the skin kininogen, and flanked N-terminally by a classical –KR- propeptide convertase processing site. The peptide was named IC-20 in accordance (I = N-terminal isoleucine, C = C-terminal cysteine, 20 = number of residues). Like the natural peptide, its synthetic replicate displayed an antagonism of bradykinin-induced arterial smooth muscle relaxation.Conclusion:IC-20 represents a novel bradykinin antagonizing peptide from amphibian skin secretions and is the third such peptide found to be co-encoded with bradykinins within skin kininogens.

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“…This conserved peptide has a molecular mass that corresponds to the described tryptophyllin, AcT-3 (see Table S4), with antimicrobial and myotropic properties (Wang et al, 2015). Tryptophyllins are small peptides that range from 400 to 900 m/z (Apponyi et al, 2004), and are produced in copious amounts by phyllomedusines in Australia and the New World (Erspamer et al, 1985) but have not been detected in other frog families, thus far (Bowie et al, 2012;König et al, 2015) except for the primitive extant frog, Ascaphus truei (Conlon et al, 2005). The bioactive role of tryptophyllins is still unclear, as some tryptophyllins (Erspamer's FPPWM-NH2) induce sleep in birds, some have myotropic properties and still others have unidentified bioactive properties (Renda et al, 1985;Apponyi et al, 2004).…”

Section: Future Directionsmentioning

confidence: 99%

Host Defense Skin Peptides Vary with Color Pattern in the Highly Polymorphic Red-Eyed Treefrog

et al. 2016

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Patterns of phenotypic variation across a geographic range provide important insights into evolutionary processes underlying diversification and speciation. Most evolutionary studies use putatively neutral markers to examine evolutionary diversification. However, functional phenotypes such as gene-encoded host-defense polypeptides (HDPs) could provide key insights into the processes of population differentiation, yet they are rarely included in population analyses. The red-eyed treefrog, Agalychnis callidryas Cope, 1862, exhibits regional variation in multiple traits, including color pattern and body size across a narrow geographic range. This treefrog produces bioactive peptides exuded onto the skin surface, presumably for pathogen and predator defense. However, the geographic patterns of variation in peptides and the factors that mediate intraspecific peptide variation across the range of this species remain untested. Here, we examine the roles of phylogenetic history, geographic barriers, geographic distance, and color-pattern variation as determinants of skin peptide diversity in 54 individuals among 11 populations across Costa Rica and Panama. Each of the five distinct Agalychnis color morphs are represented in our sample. We performed peptide mass fingerprinting and compared mass spectral data from skin peptide secretions to quantify divergence in peptide profiles among individuals, both within and among regions. We used two metrics to estimate genetic variation: Genetic distance estimated from microsatellites and patristic distance estimated from mtDNA haplotype diversity. Matrix correspondence tests revealed that skin peptide variation is best predicted by differences in leg color pattern across all regions. In addition, we found that flank color pattern and phylogeny also explain differences in peptide diversity. Patterns of peptide differentiation and phylogenetic topology were incongruent in two regions, indicating a possible role of localized selection on peptide variation. Skin peptide profiles are useful in population differentiation studies of August 2016Davis et al. Skin Peptide Variation in Agalychnis callidryasa polymorphic species as well as studies of selection and phenotype co-variation among closely related species. Our results highlight the use of skin peptides as characters for future studies of population differentiation and contribute to our understanding of biogeography in Central America.

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Bradykinin-related peptides and tryptophyllins in the skin secretions of the most primitive extant frog, Ascaphus truei

Cited by 36 publications

References 35 publications

Differential polymorphism in cutaneous glands of archaic Leiopelma species

Differential polymorphism in cutaneous glands of archaic Leiopelma species

Peptide IC-20, encoded by skin kininogen-1 of the European yellow-bellied toad, Bombina variegata, antagonizes bradykinin-induced arterial smooth muscle relaxation

Host Defense Skin Peptides Vary with Color Pattern in the Highly Polymorphic Red-Eyed Treefrog

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