Resource use and coexistence of two syntopic hylid frogs (Anura, Hylidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reproductive modes of Atlantic forest hylid frogs: A general overview and the description of a new mode

This paper reports a new reproductive mode in anurans, observed for the green treefrog, Hyla leucopygia, a species from the Atlantic Forest of Brazil and a member of the H. albosignata group. The reproductive mode of H. leucopygia is defined as follows: aquatic eggs and embryos in subterranean constructed nests; subsequent to flooding, feeding tadpoles in ponds or streams. We suggest that the new reproductive mode is widespread among the species in the H. albosignata group. The specialized courtship behaviors of H. leucopygia, characterized by vocalizations and a stereotyped sequence of mutual touches between male and female, are described. A review of the reproductive modes of hylid frogs is provided, with 11 modes recognized for the Atlantic Forest hylids and 12 modes For hylids around the world.

Anatomy of the oral cavity of hylid larvae from the genera Aplastodiscus, Bokermannohyla, and Hypsiboas (Amphibia, anura): Description and systematic implications

Internal larval oral anatomy was used to explore morphological diversity and its contribution to the systematics of the genera Aplastodiscus, Bokerinannohyla, and Hypsiboas, belonging to the tribe Cophomantini. Internal oral morphology was examined for tadpoles of 12 species. All species have a large pair of infralabial papillae on the buccal floor and other papillae on the prelingual region. In Aplastodiscus and Bokerinannohyla, the large infralabial papillae have digitiform secondary projections. The number and arrangement of the buccal floor papillae varies among species, but they are more numerous in Aplastodiscus and Bokerinannohyla. The arrangement of the postnarial papillae is variable, but in Aplastodiscus and Bokerinannohyla, they show a definite, inverted V-shape pattern. The lateral ridge papillae are more complex in larvae of Bokertnannohyla with long digitiform secondary projections. Tadpoles of only Aplastodiscus albofrenatus, Aplastodiscus eugenioi, and Bokerinannohyla luctuosa have papillae on the buccal roof arena and larvae of all species have lateral roof papillae except Hypsiboas albomarginatus and Hypsiboas cinerascens. Larvae of Aplastodiscus, Bokermannohyla, and Hypsiboas presumably share the presence of vacuities anterior to the internal nares; although this character state is clearly synapomorphic within hylids, it is still uncertain whether it is exclusive of these three genera or whether it is present in the other genera of the tribe Cophomantini (Hyloscirtus and Myersiohyla). The inclusion of internal oral anatomy characters, such as the narial vacuities, in systematic studies is certainly valuable because it will provide additional information toward the understanding of phylogenetic relationships.

Comparative feeding kinematics of tropical hylid tadpoles

Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mouthparts (i.e. labial teeth and jaw sheaths) that allow them to graze upon surfaces. The diversity in these structures among species presumably reflects specializations that allow for maximal feeding efficiency on different types of food. However, we lack a general understanding of how these oral structures function during feeding. We used high-speed digital imaging (500 Hz) to observe tadpoles of six species from the anuran family Hylidae grazing on a standardized food-covered substrate. Tadpoles of these species vary in the number of labial tooth rows, belong to two different feeding guilds (benthic and nektonic), and inhabit ponds and streams. We confirmed that the labial teeth in these species serve two functions: anchoring the mouth to the substrate and raking material off of the substrate. In general, tadpoles with a larger maximum gape or those with fewer labial tooth rows opened and closed their mouths slower than tadpoles with smaller gape or more tooth rows. Nektonic feeding tadpoles released each of their tooth rows proportionally earlier in the gape cycle compared with benthic feeding tadpoles. Lastly, we found some support for the idea that deformation of the jaw sheaths during a feeding cycle is predictable based on tadpole feeding guild. Collectively, our data show that anatomical (e.g. number of labial teeth) and ecological features (e.g. feeding guild) of tadpoles significantly influence how tadpoles open and close their mouths during feeding. © 2013. Published by The Company of Biologists Ltd.

Discovery of Novel Bacterial Cell-Penetrating Phylloseptins in Defensive Skin Secretions of the South American Hylid Frogs, Phyllomedusa duellmani and Phyllomedusa coelestis

Phylloseptin (PS) peptides, derived from South American hylid frogs (subfamily Phyllomedusinae), have been found to have broad-spectrum antimicrobial activities and relatively low haemolytic activities. Although PS peptides have been identified from several well-known and widely-distributed species of the Phyllomedusinae, there remains merit in their study in additional, more obscure and specialised members of this taxon. Here, we report the discovery of two novel PS peptides, named PS-Du and PS-Co, which were respectively identified for the first time and isolated from the skin secretions of Phyllomedusa duellmani and Phyllomedusa coelestis. Their encoding cDNAs were cloned, from which it was possible to deduce the entire primary structures of their biosynthetic precursors. Reversed-phase high-performance liquid chromatography (RP-HPLC) and tandem mass spectrometry (MS/MS) analyses were employed to isolate and structurally-characterise respective encoded PS peptides from skin secretions. The peptides had molecular masses of 2049.7 Da (PS-Du) and 1972.8 Da (PS-Co). They shared typical N-terminal sequences and C-terminal amidation with other known phylloseptins. The two peptides exhibited growth inhibitory activity against E. coli (NCTC 10418), as a standard Gram-negative bacterium, S. aureus (NCTC 10788), as a standard Gram-positive bacterium and C. albicans (NCPF 1467), as a standard pathogenic yeast, all as planktonic cultures. Moreover, both peptides demonstrated the capability of eliminating S. aureus biofilm.

Identification of three novel Phyllomedusa sauvagei dermaseptins (sVI-sVIII) by cloning from a skin secretion-derived cDNA library

The defensive skin secretions of many amphibians contain a wide spectrum of biologically active compounds, particularly antimicrobial peptides that act as a first line of defence against bacterial infection. Here we describe for the first time the identification of three novel dermaseptin-related peptides (dermaseptins sVI–sVIII) whose primary structures were deduced from cDNAs cloned from a library constructed from lyophilised skin secretion of the South American hylid frog, Phyllomedusa sauvagei. The molecular masses of each were subsequently confirmed by interrogation of archived LC/MS files of fractionated skin secretion followed by automated Edman degradation sequencing. The heterogeneity of primary structures encountered in amphibian skin antimicrobial peptides may in part be explained by individual variation—a factor essential for selective functional molecular evolution and perhaps, ultimately in speciation.

Medusins: a new class of antimicrobial peptides from the skin secretions of phyllomedusine frogs

Natural drug discovery represents an area of research with vast potential. The investigation into the use of naturally-occurring peptides as potential therapeutic agents provides a new “chemical space” for the procurement of drug leads. Intensive and systematic studies on the broad-spectrum antimicrobial peptides found in amphibian skin secretions are of particular interest in the quest for new antibiotics to treat multiple drug-resistant bacterial infections. Here we report the molecular cloning of the biosynthetic precursor-encoding cDNAs and respective mature peptides representing a novel group of antimicrobial peptides from the skin secretions of representative species of phyllomedusine leaf frogs: the Central American red-eyed leaf frog (Agalychnis callidryas), the South American orange-legged leaf frog (Phyllomedusa hypochondrialis) and the Giant Mexican leaf frog, (Pachymedusa dacnicolor). Each novel peptide possessed the highly-conserved sequence, LGMIPL/VAISAISA/SLSKLamide, and each exhibited activity against the Gram-positive bacterium, Staphylococcus aureus and the yeast, Candida albicans, but all were devoid of haemolytic effects at concentrations up to and including the MICs for both organisms. The novel peptide group were named medusins, derived from the name of the hylid frog sub-family, Phyllomedusinae, to which all species investigated belong. These data clearly demonstrate that comparative studies of the skin secretions of phyllomedusine frogs can continue to produce novel peptides that have the potential to be leads in the development of new and effective antimicrobials.

Molecular Cloning of a Novel Tryptophyllin Peptide from the Skin of the Orange-Legged Monkey Frog, Phyllomedusa hypochondrialis

Tryptophyllins are a group of small (4–14 amino acids), heterogenous peptides, mostly from the skins of hylid frogs from the genera, Phyllomedusa and Litoria. To date, more than forty TPHs have been discovered in species from these two genera. Here, we describe the identification of a novel tryptophyllin type 3 peptide, PhT-3, from the extracts of skin of the orange-legged monkey frog, Phyllomedusa hypochondrialis, and molecular cloning of its precursor-encoding cDNA from a cDNA library constructed from the same skin sample. Full primary structural characterization was achieved using a combination of direct Edman degradation, mass spectrometry and deduction from cloned skin-derived cDNA. The open-reading frame of the precursor cDNA was found to consist of 63 amino acid residues. The mature peptide arising from this precursor contains a post-translationally modified N-terminal pyroglutamate (pGlu) residue, formed from acid-mediated cyclization of an N-terminal Gln (Q) residue, and with the structure: pGlu-Asp-Lys-Pro-Phe-Trp-Pro-Pro-Pro-Ile-Tyr-Pro-Met. Pharmacological assessment of a synthetic replicate of this peptide on phenylephrine preconstricted rat tail artery segments, revealed a reduction in relaxation induced by bradykinin. PhT-3 was also found to mediate antiproliferative effects on human prostate cancer cell lines.

Karyotypic Data on 28 Species of Scinax (Amphibia: Anura: Hylidae): Diversity and Informative Variation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reproductive biology of Scinax fuscomarginatus (Anura, Hylidae) in south-eastern Brazil

The present study describes the reproductive biology of Scinax fuscomarginatus in a remnant of Cerrado in south-eastern Brazil. Observations were made between September 2002 and March 2004 at Estacao Ecologica de Itirapina, State of São Paulo, south-eastern Brazil. Breeding activities occurred in lentic and temporary bodies of water during the rainy season. Scinax fuscomarginatus exhibited a prolonged breeding pattern and a lek mating system. Males were smaller than females and defended individual calling areas through acoustic and physical interactions. Resident males consistently won encounters, but did not differ in size or mass from intruder males. Satellite behaviour was observed, but no female or amplected pair interception was registered. Scinax fuscomarginatus exhibited low operational sex ratios and the general reproductive mode in which eggs are laid in the water and tadpoles are aquatic. Amplexus was axillary and the eggs were deposited at the bottom of temporary ponds. Details on oocytes, egg masses, and eggs are included.

Tribute to R.G. Boutilier: Skin colour and body temperature changes in basking Bokermannohyla alvarengai (Bokermann 1956)

In amphibians solar basking far from water sources is relatively uncommon since the highly permeable amphibian skin does not represent a significant barrier to the accompanying risk of losing water by evaporation. A South American frog, Bokermannohyla alvarengai (Bokermann 1956), however, spends a significant amount of the day exposed to full sun and relatively high temperatures. The means by which this frog copes with potentially high rates of evaporative water loss and high body temperatures are unknown. Thus, in this study, skin colour changes, body surface temperature, and evaporative water loss rates were examined under a mixture of field and laboratory conditions to ascertain whether changes in skin reflectivity play an important role in this animal's thermal and hydric balance. Field data demonstrated a tight correlation between the lightness of skin colour and frog temperature, with lighter frogs being captured possessing higher body temperatures. Laboratory experiments supported this relationship, revealing that frogs kept in the dark or at lower temperatures (20 degrees C) had darker skin colours, whereas frogs kept in the light or higher temperatures (30 degrees C) had skin colours of a lighter hue. Light exhibited a stronger influence on skin colour than temperature alone, suggesting that colour change is triggered by the increase in incident solar energy and in anticipation of changes in body temperature. This conclusion is corroborated by the observation that cold, darkly coloured frogs placed in the sun rapidly became lighter in colour during the initial warming up period (over the first 5 min), after which they warmed up more slowly and underwent a further, albeit slower, lightening of skin colour. Surprisingly, despite its natural disposition to bask in the sun, this species does not possess a 'waterproof' skin, since its rates of evaporative water loss were not dissimilar from many hylid species that live in arboreal or semi-aquatic environments. The natural history of B. alvarengai is largely unknown and, therefore, it is likely that the herein reported colour change and basking behaviour represent a complex interaction between thermoregulation and water balance with other ecologically relevant functions, such as crypsis.

The phylogenetic relationships of the charismatic poster frogs, Phyllomedusinae (Anura, Hylidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conserved Karyotypes in Cophomantini: Cytogenetic Analysis of 12 Species from 3 Species Groups of Bokermannohyla (Amphibia: Anura: Hylidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A NEW and THREATENED INSULAR SPECIES of LANCEHEAD FROM SOUTHEASTERN BRAZIL

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)