Pharmacological Effects of Two Novel Bombesin-Like Peptides from the Skin Secretions of Chinese Piebald Odorous Frog (Odorrana schmackeri) and European Edible Frog (Pelophylax kl. esculentus) on Smooth Muscle

Bombesin-like peptides, which were identified from a diversity of amphibian skin secretions, have been demonstrated to possess several biological functions such as stimulation of smooth muscle contraction and regulation of food intake. Here, we report two novel bombesin-like peptides, bombesin-OS and bombesin-PE, which were isolated from Odorrana schmackeri and Pelophylax kl. esculentus, respectively. The mature peptides were identified and structurally confirmed by high performance Scliquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Subsequently, the effects of these purified chemically-synthetic peptides on smooth muscle were determined in bladder, uterus, and ileum. The synthetic replications were revealed to have significant pharmacological effects on these tissues. The EC50 values of bombesin-OS for bladder, uterus and ileum, were 10.8 nM, 33.64 nM, and 12.29 nM, respectively. Furthermore, compared with bombesin-OS, bombesin-PE showed similar contractile activity on ileum smooth muscle and uterus smooth muscle, but had a higher potency on bladder smooth muscle. The EC50 value of bombesin-OS for bladder was around 1000-fold less than that of bombesin-PE. This suggests that bombesin-OS and bombesin-PE have unique binding properties to their receptors. The precursor of bombesin-OS was homologous with that of a bombesin-like peptide, odorranain-BLP-5, and bombesin-PE belongs to the ranatensin subfamily. We identified the structure of bombesin-OS and bombesin-PE, two homologues peptides whose actions may provide a further clue in the classification of ranid frogs, also in the provision of new drugs for human health

A new family of diverse skin peptides from the microhylid frog genus phrynomantis

A wide range of frogs produce skin poisons composed of bioactive peptides for defence against pathogens, parasites and predators. While several frog families have been thoroughly screened for skin-secreted peptides, others, like the Microhylidae, have remained mostly unexplored. Previous studies of microhylids found no evidence of peptide secretion, suggesting that this defence adaptation was evolutionarily lost. We conducted transcriptome analyses of the skins of Phrynomantis bifasciatus and Phrynomantis microps, two African microhylid species long suspected to be poisonous. Our analyses reveal 17 evolutionary related transcripts that diversified from to those of cytolytic peptides found in other frog families. The 19 peptides predicted to be processed from these transcripts, named phrynomantins, show a striking structural diversity that is distinct from any previously identified frog skin peptide. Functional analyses of five phrynomantins confirm the loss of a cytolytic function and the absence of insecticidal or proinflammatory activity, suggesting that they represent an evolutionary transition to a new, yet unknown function. Our study shows that peptides have been retained in the defence poison of at least one microhylid lineage and encourages research on similarly understudied taxa to further elucidate the diversity and evolution of skin defence molecules

Effect to age on the geographic variation in morphometric traits among populations of Boana cordobae (Anura: Hylidae)

La variación morfométrica del tamaño corporal es un aspecto importante de la historia natural de las especies, que ha sido de particular interés. En este estudio se estimaron diferencias en el tamaño corporal y la estructura de edad de seis poblaciones de Boana cordobae que viven a diferentes altitudes, 808-2 310 m.a.s.l. en las provincias de Córdoba y San Luis (Argentina). La técnica de esqueletocronología se utilizó para la determinación de la edad, mediante la medición de 15 variables morfométricas en 79 individuos. Las variables morfométricas mostraron diferencias significativas entre sexos, siendo las hembras de mayor tamaño que los machos, incluso cuando el efecto de la edad se tuvo en cuenta; y se encontró una relación significativa entre la edad y la mayoría de las variables morfométricas. Cuando el efecto de la edad fue removido, se encontraron diferencias significativas en el tamaño del cuerpo entre las poblaciones estudiadas. Machos de poblaciones de mayor altitud son más grandes que los de altitudes menores. Estos resultados sugieren que las diferencias en la estructura de edad entre las poblaciones es un factor de importancia a tener en cuenta para analizar la variación en el tamaño corporal de esta especie según el área geográfica.The morphometric variation of body size is an important topic of the natural history of the species which has been received particular interest. In this study, we estimated differences in body size and age structure of six populations of Boana cordobae living at different altitudes, 808-2 310 m.a.s.l. in Córdoba and San Luis provinces (Argentina). We measured 15 morphometric variables and used skeletochronology to age determina- tion of 79 individuals. Morphometric variables showed significant differences between sexes, being females larger than males, even when the effect of age was taken into account. We found a significant relationship between age and most of the morphometric variables. When removing the effects of age, we found significant inter-population differences in body size. Males from the high-elevation populations were larger than individuals from low-elevation populations. These results suggest that a difference in age structure between populations is a main factor for the geographic variation in body size of this species.Fil: Baraquet, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; ArgentinaFil: Otero, Manuel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; ArgentinaFil: Grenat, Pablo Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; ArgentinaFil: Babini, María Selene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; ArgentinaFil: Martino, Adolfo Ludovico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Ecología; Argentin

Neurophysiology

Contains reports on eight research projects.Bell Telephone Laboratories, Inc.Teagle Foundation, Inc.National Science Foundation (Grant GP-2495)National Institutes of Health (Grants MH-04737-04)National Institutes of Health (NB-04985-01)U. S. Air Force. Aeronautical Systems Division (Contract AF 33(615)-1747)U. S. Air Force. Cambridge Research Laboratories (Contract AF19(628)-3807)U. S. Air Force. Electronic Systems Division (Contract AF19(628)-4147)National Aeronautics and Space Administration (Grant NsG-496

First report of Lividin and Spinulosain peptides from the skin secretion of an Indian frog

Here, we report two novel peptides identified from the skin secretion, having homologies to Lividin and Spinulosain, of an endemic frog, Hydrophylax bahuvistara, of Western Ghats. This is the first report of these peptides from Indian frogs and first identification of Lividin from the Hydrophylax genus. Both peptides exhibited weak antimicrobial activity but very low haemolytic activity. The problems of naming amphibian host defense peptides (HDPs) are also discussed

Massive Molecular Parallel Evolution of the HSP90AA1 Gene between High-elevation Anurans

HSP90AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90AA1 gene in high elevation amphibians. IISP90AA1 gene sequences of four high-elevation anurans, Bufo gargarizans, Nanorana parkeri, Rana kukunoris, and Scutiger boulengeri, were compared along with five of their low-elevation relatives. A total of 16 amino-acid sites were identified as parallel evolution between N parkeri and R. kukunoris. We generated both model based (Zhang and Kumar's test) and empirical data based (parallel/divergence plotting) null distributions for non-parallel evolution, and both methods clearly determined that the observed number of parallel substitutions were significantly more than the null expectation. Furthermore, on the HSP90AA1 gene tree, N. parkeri and R. kukunoris formed a strongly supported Glade that was away from their respective relatives. This study provides a clear case of molecular parallel evolution, which may have significant implications in understanding the genetic mechanisms of high-elevation adaptation

Changes in the Olfactory Response to Amino Acids in Japanese Newts After Transfer from an Aquatic to a Terrestrial Habitat

Amphibians are capable of smelling both volatile and water-soluble (e.g., amino acids) odorants. Adult Japanese newts, Cynops pyrrhogaster, live mostly in water, except during hibernation, but sometimes on land. To examine olfactory responses of the newts to adaptation to a short-term stay on land (land adaptation), we measured the magnitude of the olfactory response at five different time points (land adaptation time: 0, 30, 54, 90, and 114 h after transfer from an aquatic to a terrestrial habitat by using electro-olfactogram (EOG) recordings. Statistical analysis by the weighted linear model (P < 0.05) indicated that the time to land adaptation had a significant effect on the magnitude of the EOG induced by 1 µM and 10 µM amino acid mixtures. Further, the slope estimates of the weighted linear model were significantly positive (P < 0.05). These results indicate that the magnitude of the EOG response to amino acid mixtures (arginine, alanine, proline, and glutamic acid) significantly increases with land adaptation time. On the other hand, we observed no significant relationship between the magnitude of the EOG response induced by an 0.05% volatile odorant mixture (isoamyl acetate, n-amyl acetate, cineole, and limonene) and land adaptation time. Our results indicate that olfactory sensitivity to amino acids significantly increases with land adaptation time in adult Japanese newts