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1.
Aquat Toxicol ; 222: 105470, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32199138

RESUMO

Cadmium (Cd) a highly toxic metal to human and wildlife health and it is hazardous to both terrestrial and aquatic life. In this study, we used RNA sequencing analysis to examine the effects of chronic cadmium exposure on liver lipid metabolism of Bufo gargarizans larvae. Tadpoles were exposed to cadmium concentrations at 0, 5, 10, 50, 100 and 200 µg L-1 from Gosner stage 26-42 of metamorphic climax. The results showed high dose cadmium (50, 100 and 200 µg L-1) caused obvious histological changes characterized by hepatocytes deformation, nuclear pyknosis, increasing melanomacrophage centers (MMCs) and aggregated lipid droplets. Moreover, transcriptome analysis showed that liver function was seriously affected by cadmium exposure. Furthermore, high dose cadmium significantly upregulated the mRNA expression of elongation of very-long-chain fatty acids 1 (ELOVL1), Mitochondrial trans-2-enoyl-CoA reductase (MECR), Trans-2, 3-enoyl-CoA reductase (TER) and Hydroxysteroid (17ß) dehydrogenase type 12 (HSD17B12) which are related with fatty acid synthesis. Meanwhile, mRNA levels of genes related with fat acid oxidation such as acetyl-CoA acyltransferase 2 (ACAA2) and enoyl-coenzyme A (CoA) hydratase short chain 1 (ECHS1) were significantly upregulated while the expression of Acyl-coA thioesterase 1 (ACOT1), 3-hydroxyacyl-CoA dehydrogenase (HADH), Palmitoyl-protein thioesterase 1(PPT1) and Acetyl-CoA acyltransferase 1(ACAA1) was significantly downregulated by high dose cadmium exposure. Furthermore, the mRNA level of ATP-binding cassette subfamily B member 11 (ABCB11) related with bile secretion was significantly decreased exposed to high dose cadmium. Our results suggested cadmium can cause liver dysfunction by inducing histopathological damages, genetic expression alterations and fatty acid metabolism disorder.


Assuntos
Cádmio/toxicidade , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Larva/efeitos dos fármacos , Fígado/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Bufonidae , Enoil-CoA Hidratase/metabolismo , Larva/genética , Larva/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Oxirredução , RNA Mensageiro/metabolismo
2.
Ecotoxicol Environ Saf ; 195: 110523, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32222598

RESUMO

Cadmium (Cd) is carcinogenic to human and it also has adverse effects on aquatic life such as amphibian larvae. However, its influences on amphibian gut morphology and development as well as intestinal microbiota are still hardly understood. In this study, we examined the effects of chronic cadmium exposure on the gut of tadpoles at Gosner stage 42 of metamorphic climax by using Bufo gargarizans as a model species. Tadpoles were exposed to cadmium concentrations at 0, 5, 100 and 200 µg L-1 from Gosner stage 26-42. The results showed that high cadmium (100 and 200 µg L-1) exposure caused significant decrease of body length and weight but significant increase of intestinal length and weight. Moreover, severe histopathological damages were induced by high Cd exposure. In addition, microbial communities in the gut of tadpoles in high cadmium exposure groups were remarkably different from those in control group. Unexpectedly, species diversity and richness were higher in the intestinal microbiota of 200 µg L-1 cadmium exposure group. Furthermore, the abundance of prevalent phyla, families and genera of intestinal microbiota were changed by cadmium exposure. Meanwhile, cadmium exposure perturbed gut renewal functions and the relative mRNA expression of genes involved in canonical and non-canonical Wnt signaling pathway was seriously affected by high cadmium exposure. We concluded that cadmium could be harmful to tadpole health by inducing intestinal histopathological damages, gut remodeling inhibition and intestinal microbiota alterations.


Assuntos
Cádmio/toxicidade , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Larva/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Bufonidae , Relação Dose-Resposta a Droga , Intestinos/microbiologia , Intestinos/patologia , Larva/crescimento & desenvolvimento
3.
Toxicon ; 178: 4-7, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32081637

RESUMO

In recent years, SE Brazil, the most populous region in the country with an estimated population of 88 million, has been experiencing an alarming increase in scorpions accidents (scorpionism), mainly caused by the yellow scorpion (Tityus serrulatus), or "escorpião amarelo" in Portuguese. This species is considered particularly dangerous to humans and can reproduce by parthenogenesis favouring rapid dispersal and colonization of new environments. Since the 1940s, owing to the growing danger represented by scorpionism, public control policies have been developed, including active search for scorpions, together with the use of toxic substances applied in places most likely to serve as their refuges. Even so, the number of accidents is increasing year by year, presently at an alarming rate. It seems evident that the increase in accidents is directly (or primarily) related to the lack of predators that in healthy environmental conditions would naturally control scorpion populations. However, due to environmental changes, leading to a lack of predators, scorpions have been gradually invading the urban environment. Arachnids and insects in general, as well as some other invertebrates, are preyed upon by anuran amphibians (toads, frogs and tree frogs). Toads (family Bufonidae) are nocturnal, large, and highly voracious animals, capable of actively exploring extensive areas and consuming large numbers of insects and arachnids daily. One of the most common toad species in southeastern Brazil is Rhinella icterica. Both R. icterica and T. serrulatus inhabit the same nocturnal environment. The predatory action of toads, specifically on scorpions, is practically unknown from behavioural and toxinological points of view. Thus, we studied the predatory behaviour of this toad against the yellow scorpion and evaluated the resistance of the amphibian to scorpion venom. Our results show that R. icterica is a voracious predator of T. serrulatus and is extremely resistant to its venom. Human/toad relationship throughout western history has always been very conflicted and possibly one of the factors that most has contributed to human ignorance of the role of these amphibians in maintaining ecological balance. Presently, the control of scorpionism is being performed through active search and/or the use of chemical agents, although showing little efficacy in reducing human accidents. In the medium or long term, more effective actions taking into account the biology of scorpions and their predators have never been taken to reduce these accidents.


Assuntos
Bufonidae/fisiologia , Picadas de Escorpião/epidemiologia , Venenos de Escorpião , Escorpiões , Animais , Brasil/epidemiologia , Humanos , Controle Biológico de Vetores/métodos
4.
Toxicon ; 177: 89-92, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32061723

RESUMO

American trypanosomiasis is a parasitic neglected disease, responsible for the death of approximately 10,000 people every year. Amphibians are recognized for producing in their cutaneous glands substances with pharmacological potential against a variety of pathologies. Here we investigated the antiprotozoal activity against Trypanosoma cruzi of bufadienolides isolated from the parotoid glands secretions of the toad Rhinella centralis from Panama. NMR and mass spectrometry analysis led to the identification of the active compound 19-hydroxy-bufalin, for which its antitrypanosomal activity and occurrence in the genus Rhinella are reported for the first time. This compound showed low cytotoxicity and significant selectivity which confers to it a potential role for the treatment of Chagas disease.


Assuntos
Venenos de Anfíbios/toxicidade , Bufanolídeos/toxicidade , Bufonidae , Trypanosoma cruzi/efeitos dos fármacos , Animais , Bufanolídeos/isolamento & purificação
5.
Zoolog Sci ; 37(1): 91-101, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32068378

RESUMO

Two lineages of stream toads in the genus Ansonia from Malaysian Borneo have long been suspected to be specifically distinct on the basis of molecular data. We assessed the taxonomic status of these lineages using morphological and additional genetic data. In mtDNA phylogeny, each lineage-one from Bario, Kelabit Highlands of Sarawak, the other from Mt. Mulu of Sarawak and the Crocker Range of Sabah-is separated from other congeners by large genetic distances, comparable with those observed between heterospecific species in the genus. These lineages are also morphologically distinguishable from other species, and are considered to represent valid, independently evolving species. We therefore describe them as A. kelabitensis sp. nov. and A. kanak sp. nov.


Assuntos
Bufonidae/anatomia & histologia , Bufonidae/classificação , Animais , Bornéu , Bufonidae/genética , Bufonidae/crescimento & desenvolvimento , DNA Mitocondrial/genética , Feminino , Larva/anatomia & histologia , Masculino , Filogenia , Especificidade da Espécie
6.
Chemosphere ; 247: 125925, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32069717

RESUMO

Environmental pollutants could change the intestinal microbiota communities, while data concerning the dynamics of the intestinal microbiota in response to different environmental chemicals in amphibian are lacking. We compared the effects of Cu, Cd, Cr and NO3-N on intestinal microbiota of B. gargarizans tadpoles by using high-throughput 16S rRNA sequencing technology. Our results revealed that responses of intestinal microbiota to three metals and NO3-N showed different characteristics. At the phylum level, the most 100 OTUs were predominantly colonized by Proteobacteria, and meanwhile, expansion of Proteobacteria was observed in Cu 64 µg/L, Cd (100 µg/L and 200 µg/L) and NO3-N100 mg/L treatment groups. In addition, the abundance of Bacteroidetes significantly increased in the gut administrate with Cu, Cd, Cr, NO3-N 20 mg/L exposures, while declined abundance of Fusobacteria was observed in Cu64 µg/L Cd100 µg/L Cd200µg/L-exposed groups. At the genus level, several genera exhibited increased prevalence of abundance such as Shewanella, Azospira and Flavobacterium. The functional prediction revealed that exposures of three metals and NO3-N increase the risks of metabolic disorders and diseases. Our research could be an important step toward an assessment of the ecological risks of different chemicals to aquatic organisms using intestinal microbiota.


Assuntos
Bufonidae/microbiologia , Poluentes Ambientais/toxicidade , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Bacteroidetes/genética , Bufonidae/genética , Cádmio/farmacologia , Microbioma Gastrointestinal/fisiologia , Larva/efeitos dos fármacos , Metais/toxicidade , Nitratos/toxicidade , RNA Ribossômico 16S/genética
7.
Chemosphere ; 243: 125437, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995885

RESUMO

Hexavalent chromium is one of the major detrimental heavy metal pollutants. B. gargarizans tadpoles were treated with different concentrations of Cr6+ (0, 13, 52, 104, 208, and 416 µg Cr6+ L-1) from Gs 2 to Gs 42. The effect of Cr6+ on histopathological alterations and transcript levels of fatty acid metabolism-related genes as well as fatty acids composition and content in liver were examined. Histopathological changes were observed in liver at 52, 104, 208, and 416 µg Cr6+ L-1. Moreover, RT-qPCR analyses showed the downregulated mRNA levels of the genes related to fatty acid synthesis (SCD, MECR, TECR and ELOVL1) and fatty acid ß-oxidation (ACOT1, PPT1, HADH and ACAA2) at 416 µg Cr6+ L-1. However, the mRNA expression of fatty acid ß-oxidation-related genes (ECHS1, HADHA and ACAA1) were significantly upregulated at 13, 52, 104, 208 and 416 µg Cr6+ L-1. In situ hybridization revealed BSEP was expressed in hepatocyte nucleus and plasma membrane, and HSD17B12 was abundantly expressed in the plasma membrane. The HSD17B12 mRNA levels were significantly upregulated in tadpoles exposed to all Cr6+ treatment groups, while the BSEP mRNA levels were downregulated at 104, 208 and 416 µg Cr6+ L-1 groups compared to control. In addition, an increase in polyunsaturated fatty acids and a decrease in monounsaturated fatty acids were found in 52, 104 and 416 µg Cr6+ L-1 groups. Overall, chronic exposure to Cr6+ may suppress fatty acid synthesis, disturb fatty acid ß-oxidation, aggravate disorders of hepatic function and induce hepatic impairment in B. gargarizans tadpoles.


Assuntos
Cromo/toxicidade , Larva/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Animais , Bufonidae , Cromo/farmacologia , Ácidos Graxos/metabolismo , Larva/genética , Larva/metabolismo , Metabolismo dos Lipídeos/genética , Oxirredução , RNA Mensageiro/metabolismo
8.
J Helminthol ; 94: e119, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31959277

RESUMO

Pseudoacanthocephalus goodmani n. sp. is described from faecal pellets collected from Sclerophrys gutturalis (Power, 1927), the guttural toad. The species is characterized by a suite of characters, including a proboscis armature of 14-18 longitudinal rows of 4-6 hooks with simple roots, lemnisci longer than the proboscis receptacle, equatorial testes, a cluster of elongated cement glands and eggs without polar prolongations of the middle membrane 72.6-85.8 long. The toad had been accidentally translocated from Mauritius to the UK in a tourist's luggage and survived a washing machine cycle. The guttural toad was introduced into Mauritius from South Africa in 1922 and the cane toad, Rhinella marina (Linneaus, 1758), from South America, between 1936 and 1938. It seems most likely, therefore, that P. goodmani was introduced, with the guttural toad, from South Africa. The cane toad is host to the similar species, Pseudoacanthocephalus lutzi, from the Americas, but P. lutzi has not been recorded from places where the cane toad has been introduced elsewhere. Clearly, the guttural toad is a hardy and adaptable species, although it seems unlikely that it could become established in Northern Europe. Nevertheless, any accidental translocation of hosts poses the potential risk of introducing unwanted pathogens into the environment and should be guarded against.


Assuntos
Acantocéfalos/classificação , Bufonidae/parasitologia , Acantocéfalos/isolamento & purificação , Animais , Espécies Introduzidas , Maurício
9.
Chemosphere ; 245: 125623, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31855759

RESUMO

Glyphosate (GLY)-dicamba (DIC) and GLY-flurochloridone (FLC) are herbicide mixtures which are widely used for treating fallow containing glyphosate resistant weeds. The aim of this study was to evaluate the acute toxic effects and the prevailing interactions on stage 36 tadpoles of the anuran species Rhinella arenarum when exposed to equitoxic and non-equitoxic combinations of these herbicide combinations. Experiments were realized using the following combinations of commercial formulations: 48% GLY-based Credit® + 57.71% DIC-based Banvel® and 48% GLY-based Credit® + 25% FLC-based Twin Pack Gold®. GLY-DIC and GLY-FLC equitoxic mixtures were assayed mixing each constituent with an equivalent individual toxicity able to induce the same lethality effect. After 96 h of exposure, GLY-DIC and GLY-FLC equitoxic mixtures presented toxic unit 50 values (TU50 96h) of 1.74 (confidence interval: 1.58-1.92) and 1.54 (confidence interval: 1.46-1.62) respectively, indicating the presence of a weak antagonistic interaction as TU values were greater than 1. For their part, most non-equitoxic combinations of GLY-DIC and GLY-FLC tested did not significantly differ from additivity, the only exception being when DIC and FLC were fixed at 0.33 TUs, where a weak antagonism was observed. Overall, results indicate that the toxicity of both GLY-DIC and GLY-FLC mixtures to R. arenarum tadpoles vary from additive to slightly antagonistic, depending on the proportion of constituting herbicide formulations present in the mixture.


Assuntos
Bufonidae , Dicamba/toxicidade , Glicina/análogos & derivados , Herbicidas/toxicidade , Larva/efeitos dos fármacos , Animais , Anuros , Misturas Complexas/toxicidade , Antagonismo de Drogas , Glicina/toxicidade , Pirrolidinonas/toxicidade
10.
J Ethnopharmacol ; 246: 112178, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31445132

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Bufo gargarizans (Cantor, 1842) (BGC), a traditional medicinal animal distributed in many provinces of China, is well known for the pharmaceutical value of Chansu and Chanpi. As traditional Chinese medicines (TCMs), Chansu and Chanpi, with their broad-spectrum of therapeutic applications, have long been applied to detoxification, anti-inflammation, analgesia, etc. OVERARCHING OBJECTIVE: We critically analyzed the current evidence for the traditional uses, chemical profiles, pharmacological activity, toxicity and quality control of BGC (Bufonidae family) to provide a scientific basis for future in-depth studies and perspectives for the discovery of potential drug candidates. METHODOLOGY: All of the available information on active constituents and TCMs derived from BGC was obtained using the keywords "Bufo gargarizans", "Chansu", "Chanpi", "Huachansu", or "Cinobufacini" through different electronic databases, including PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI), the Wanfang Database, and Pharmacopoeia of China. In addition, Chinese medicine books from different times were used to elucidate the traditional uses of BGC. Electronic databases, including the "IUCN Red List of Threatened Species", "American Museum of Natural History" and "AmphibiaWeb Species Lists", were used to validate the scientific name of BGC. RESULTS: To date, about 118 bufadienolide monomers and 11 indole alkaloids have been identified from BGC in total. The extracts and isolated compounds exhibit a wide range of in vitro and in vivo pharmacological effects. The literature search demonstrated that the ethnomedicinal uses of BGC, such as detoxification, anti-inflammation and the ability to reduce swelling and pain associated with infections, are correlated with its modern pharmacological activities, including antitumor, immunomodulation and attenuation of cancer-derived pain. Bufadienolides and indole alkaloids have been regarded as the main active substances in BGC, among which bufadienolides have significant antitumor activity. Furthermore, the cardiotoxicity of bufadienolides was discussed, and the main molecular mechanism involves in the inhibition of Na+/K+-ATPase. Besides, with the development of modern analytical techniques, the quality control methods of BGC-derived TCMs are being improved constantly. CONCLUSIONS: An increasing number of reports suggest that BGC can be regarded as an excellent source for exploring the potential antitumor constituents. However, the future antitumor research of BGC needs to follow the standard pharmacology guidelines, so as to provide comprehensive pharmacological information and aid the reproducibility of the data. Besides, to ensure the efficacy and safety of BGC-derived TCMs, it is vital to construct a comprehensive quality evaluation model on the basis of clarifying pharmacodynamic-related and toxicity-related compositions.


Assuntos
Bufonidae/metabolismo , Medicina Tradicional Chinesa , Animais , Bufanolídeos/farmacologia , Bufanolídeos/uso terapêutico , Bufanolídeos/toxicidade , Humanos , Controle de Qualidade
11.
Dis Aquat Organ ; 137(2): 89-99, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31854327

RESUMO

Pathogenic water molds have a significant impact on many species, especially amphibians. The genus Saprolegnia is a pathogenic oomycete restricted to aquatic and moist habitats, and its presence is strongly linked to the abundance of amphibians and fishes. We investigated the influence of Saprolegnia presence on egg mortality and egg occurrence under varying environmental conditions in the Asiatic toad Bufo gargarizans at 27 breeding sites in the Republic of Korea. We then assessed the impact of Saprolegnia on the presence of B. gargarizans at the 27 sites surveyed weekly during the B. gargarizans breeding season for 3 consecutive years. We used molecular tools to identify the water molds as belonging to an undescribed S. ferax strain. We demonstrated that the presence of S. ferax was positively associated with higher water conductivity and ponds. In addition, while S. ferax prevalence was associated with a reduction in B. gargarizans breeding activity and breeding success, we could not determine its impact on the subsequent breeding seasons. Our study highlights the potential negative effects of Saprolegnia on amphibian reproduction, although additional research is necessary to determine the relationship between Saprolegnia, its hosts and the impacts of habitat loss on amphibians.


Assuntos
Bufonidae , Saprolegnia , Animais , Fungos , Infecções , República da Coreia
12.
Biol Lett ; 15(11): 20190689, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31718512

RESUMO

Shifts between habitats during reproduction can induce costs that are independent of the reproductive effort and that often apply to both sexes. Such shifts can also illustrate physiological costs complementary to those involving energetic currencies. In this study, we investigated osmotic consequences of reproduction in a context where reproduction induces a shift from terrestrial habitats to freshwater environments. During reproduction, toads migrate to breeding ponds where males remain for several weeks, while females leave shortly after egg-laying. We assessed plasma osmolality of male spined toads during the whole reproductive period (approx. 30 days) in conjunction with markers of individual condition. We found that osmolality decreases during the protracted period of immersion in freshwater during reproduction, presumably through water influx as indicated by body mass changes. Hormonal markers of metabolism and sexual activity were positively correlated with osmolality. Recent research has highlighted hydric 'costs' of reproduction when access to water is limited. Our study adds to this growing field of investigation, yet with an opposite perspective, where water availability linked to reproduction provokes hyperhydration rather than dehydration.


Assuntos
Bufonidae , Reprodução , Animais , Cruzamento , Ecossistema , Feminino , Masculino , Água
13.
Reprod Biol Endocrinol ; 17(1): 92, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711511

RESUMO

BACKGROUND: Amphibian diversity is declining at an alarming rate due to habitat loss, invasive species, climate change and diseases. Captive assurance colonies have been established for some species at risk; however, many species do not breed well in captivity and the development of assisted reproductive technologies (ART) is critical to help sustain genetic diversity. To date, the majority of the work has been accomplished in species from the American continent and Australia, and there is a need to address similar breeding challenges in Eurasian and African species of amphibians. METHODS: The aim of this study was to develop a hormone protocol for stimulation of spermiation in Epidalea calamita as a model for Eurasian bufonids. Hence, the effect on sperm production and quality of three doses of chorionic gonadotropin hormone (5, 10 and 15 IU hCG/g) over time (1 to 24 h) was evaluated. In addition, cold storage (at 5 °C) of sperm for 24 and 48 h and three frequencies for hormonal treatment (weekly, biweekly and monthly) were examined. RESULTS: Hormone concentrations of 10 or 15 IU of hCG induced spermiation in 100% of males and produced sperm of comparable quality, while 5 IU hCG stimulated spermiation in only 40% of males. Total motility peaked between 1 to 4 h post-treatment with 10 IU hCG, whereas treatment with 15 IU hCG peaked between 2 to 6 h. After 24 h of cold storage total motility dropped by 20% and forward motility dropped by 10% for both the 10 and 15 IU treatments. Weekly hormone administration resulted in higher variation between trials in all motility parameters and a lower overall Total Motility and Forward Movement. Furthermore, the effect of exogenous hormone treatment overlapped between the last two trials in the weekly frequency. Sperm concentration was higher in the first trial for all frequencies but showed no differences among other trials. CONCLUSIONS: Overall, these results show that hormone concentration, time after treatment, frequency of hormone treatment and cold storage should be borne in mind when developing a hormone stimulation protocol for Eurasian amphibian species.


Assuntos
Bufonidae/fisiologia , Gonadotropina Coriônica/farmacologia , Espermatogênese/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Animais , Ásia , Criopreservação , Relação Dose-Resposta a Droga , Europa (Continente) , Humanos , Masculino , Técnicas de Reprodução Assistida , Estações do Ano , Contagem de Espermatozoides , Espermatozoides/fisiologia , Fatores de Tempo
14.
BMC Evol Biol ; 19(1): 208, 2019 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-31706264

RESUMO

BACKGROUND: Two previous studies on interspecific body size variation of anurans found that the key drivers of variation are the species' lifestyles and the environments that they live in. To examine whether those findings apply at the intraspecific level, we conducted a study of the Asian common toad (Duttaphrynus melanostictus), a terrestrial anuran distributed in tropical regions. The body size of toads from 15 locations, covering the majority of their geographic range, and local environmental data were summarized from published literature. We used a model selection process based on an information-theoretic approach to examine the relationship between toad body size and those environmental parameters. RESULTS: We found a positive correlation between the body size of the Asian common toad and the water deficit gradient, but no linkage between body size and temperature-related parameters. Furthermore, there was a positive correlation between the seasonality of precipitation and body size of females from different sampled populations. CONCLUSIONS: As a terrestrial anuran, the Asian common toad should experience greater pressure from environmental fluctuations than aquatic species. It is mainly distributed in tropical regions where temperatures are generally warm and stable, but water availability fluctuates. Therefore, while thermal gradients are not strong enough to generate selection pressure on body size, the moisture gradient is strong enough to select for larger size in both males and females in dryer regions. Larger body size supports more efficient water conservation, a pattern in accordance with the prediction that lifestyles of different species and their local habitats determine the relationship between body size and environment. In addition, larger females occur in regions with greater seasonality in precipitation, which may happen because larger females can afford greater reproductive output in a limited reproductive season.


Assuntos
Tamanho Corporal , Bufonidae/fisiologia , Animais , Ásia , Ecossistema , Feminino , Masculino , Reprodução , Estações do Ano , Temperatura , Tempo (Meteorologia)
15.
Zootaxa ; 4577(2): zootaxa.4577.2.5, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31715724

RESUMO

Here we describe a new species of the toad genus Amazophrynella (Bufonidae) from the south margin of the Amazon River in Santarém, state of Pará, Brazilian Amazonia. The new species can be diagnosed by (1) medium body size for the genus: adult females 19.5-20.4 mm SVL, adult males 13.0-14.5 mm SVL; (2) snout acuminate in lateral view; (3) Finger I larger and robust; (4) Finger I nearly equal in size than Finger II; (5) palmar tubercle rounded, covering » of hand; (6) pigmented callus in Finger I in males; in life: (7) brown stain on throat and chest; (8) black dots on venter. Males emit two distinct advertisement calls: the call type 1 consists of a relatively long note (mean 0.248 s) with a mean dominant frequency of 3526 Hz. The call type 2 is arranged in bouts of 6 to 22 notes with mean dominant frequency of 3450 Hz and much shorter note durations (mean 0.034 s). In this study we also redescribe the advertisement call of A. minuta, which also emits a second call type.


Assuntos
Anuros , Bufonidae , Animais , Tamanho Corporal , Brasil , Feminino , Masculino , Rios , Vocalização Animal
16.
Zootaxa ; 4679(2): zootaxa.4679.2.9, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31715964

RESUMO

Using a combination of morphological and molecular data we recognize three new species of Puppet Toad, Sigalegalephrynus Smart, Sarker, Arifin, Harvey, Sidik, Hamidy, Kurniawan Smith, a recently described genus endemic to the highland forests of Sumatra, Indonesia. Phylogenetic analysis of mitochondrial DNA sequences recovered a monophyletic relationship among all Puppet Toads, with two distinct evolutionary clades, a northern and a southern. The northern clade includes Sigalegalephrynus gayoluesensis sp. nov., and S. burnitelongensis sp. nov., and the southern clade includes S. harveyi sp. nov., S. mandailinguensis, and S. minangkabauensis. With the discovery of these three new species, Sigalegalephrynus contains more endemic species than any other genus of toad in Indonesia. We used maximum entropy, implemented in MaxEnt, to identify suitable habitats and occurrence probability of additional undescribed new species from the island. The most important predictors of Sigalegalephrynus distribution were elevation (64.5%) and land cover (7.11%). Based on the probability of presence, it is likely that there are many more species of the genus awaiting discovery in Sumatra. Our analysis, based on IUCN Red List of Threatened Species category and criteria, shows that all of the five species of Sigalegalephrynus are in great risk of extinction and should be placed into the Endangered (EN) category of IUCN Red List.


Assuntos
Anuros , Bufonidae , Animais , Espécies em Perigo de Extinção , Indonésia , Filogenia
17.
Zootaxa ; 4656(3): zootaxa.4656.3.11, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31716818

RESUMO

A new species of Ansonia is described from the Shan Plateau of Myanmar based on an integrative taxonomic analysis that differentiates it from all other congeners. Molecular phylogenetic analyses based on the mitochondrial genes 12S and 16S rRNA and tRNA-val recover A. kyaiktiyoensis sp. nov. as the sister species to A. inthanon from Thailand but differs from it and other congeners by at least a 5.0% sequence divergence. It is further differentiated by the following combination of morphological characters: (1) maximum SVL 24 mm in males and females; (2) first finger shorter than second; (3) absence of interorbital and tarsal ridges; (4) presence of light-coloured interscapular spot; (5) presence of yellow rictal tubercle; (6) absence of wide, light-coloured patch below eye; (7) presence of large, discrete, bright-yellow submandibular spots along the underside of lower jaw; (8) iris yellow-gold; (9) presence of markings on the snout consisting of streaks below the eye to the lip, and on the canthus rostralis to the nostril; (10) dorsum grey-brown with orange-beige spots, a dark-brown X-shaped marking on the back surrounding the interscapular spot, and dark-coloured markings on rump; (11) fore- and hind limbs with orange-beige cross-bars; and (12) venter light-gray with yellow spotting, especially near flanks and underside of hind limbs. Ansonia kyaiktiyoensis sp. nov. is the westernmost known record for the genus and the only species west of the Salween Basin. Its discovery echoes the increasing number of herpetological discoveries being made in upland regions fringing the Ayeyarwady and Salween Basins.


Assuntos
Anuros , Bufonidae , Animais , Feminino , Masculino , Mianmar , Filogenia , RNA Ribossômico 16S , Tailândia
18.
Zootaxa ; 4648(1): zootaxa.4648.1.2, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31716958

RESUMO

Dendrophryniscus brevipollicatus Jiménez de la Espada is a Neotropical bufonid endemic to a small range of the Brazilian Coastal Atlantic Forest, with reduced body size for the family and bromeligenous habit. We reviewed the taxonomic status of populations of D. brevipollicatus from states of Rio de Janeiro and São Paulo, including some continental islands, based on external morphology. We tested our morphological species by a DNA-barcoding approach with sequences of 16S RNA ribosomal gene fragment. DNA-barcoding analysis included other recognized Dendrophryniscus species and was concordant with morphological species diagnosed in our review. Intraspecific genetic distances ranged from 0 to 2.72 % (± 0.91 %). Interspecific distances ranged from 3.35 % (± 0.90 %) to 20.15 (± 2.23 %). Optimal threshold values ranged from 2.8 % to 3.0 % and barcode gap analysis showed that for all individuals the furthest intraspecific distances was always lower than the closest non-conspecific individual. Seven distinct species were recognized. A neotype for D. brevipollicatus was designated and described; the type locality was determined for the Açude da Solidão (22º57'S, 43º17'W, Datum WGS 84; 410 m altitude), Parque Nacional da Tijuca, Municipality of Rio de Janeiro, State of Rio de Janeiro, Brazil. Two species were revalidated: D. imitator (Miranda-Ribeiro), with designation of a lectotype and descriptions of the lectotype and of a topotype from the restricted type locality, Alto da Serra (23o46'S, 46o19'W, Datum WGS 84, 800 m altitude), Municipality of Paranapiacaba, State of São Paulo, Brazil; and D. lauroi (Miranda-Ribeiro), with descriptions of the lectotype and of a topotype from the type locality, Municipality of Angra dos Reis (22o54'S, 44o20'W, Datum WGS 84; 25 m altitude), State of Rio de Janeiro, Brazil. Four new species were described: D. davori sp. nov., from Baixo Caledônia (22º21'S, 42º35'W, Datum WGS 84; 1600 m altitude), Municipality of Nova Friburgo, State of Rio de Janeiro, Brazil; D. haddadi sp. nov., from Parque Estadual da Serra do Mar, Núcleo Santa Virgínia (23o21'S, 45o08'W, Datum WGS 84; 970 m altitude), Municipality of São Luís do Paraitinga, State of São Paulo, Brazil; D. izecksohni sp. nov., from Campo de Fruticultura da Bocaina (currently Núcleo Senador Vergueiro), Municipality of São José do Barreiro (22º38'S, 44º34'W, Datum WGS 84, 540 m altitude), State of São Paulo, Brazil; and D. jureia sp. nov., from Estação Ecológica da Juréia-Itatins-Núcleo Rio Verde (24º22'S, 47º04'W, Datum WGS 84; 32 m altitude), Municipality of Iguape, State of São Paulo, Brazil. Geographical distributions of all species are provided.


Assuntos
Bufonidae , Animais , Brasil , Florestas
19.
Behav Processes ; 169: 103982, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31586643

RESUMO

Vocal mimicry is taxonomically widespread among birds, but little is known about mimicry of non-avian models. Prior studies show preferential imitation of avian models whose sounds are acoustically similar to the non-imitative songs of the vocal mimic. Based on these studies and anecdotes about frog imitations by northern mockingbirds (Mimus polyglottos), we hypothesized which anuran models would be most likely to get imitated by mockingbirds across their geographic range. We tested our hypothesis using >40 h of archived mockingbird recordings. Our results showed that mockingbirds imitated at least 12 anuran species, and calls were disproportionately mimicked when they contained dominant frequencies within the vocal range of the mockingbird (750-7000 Hz). Mockingbirds also frequently modified model anuran sounds by leaving out formants and/or truncating call duration. Our results represent the most comprehensive survey for any mimicking species of the imitation of anurans.


Assuntos
Comportamento Animal/fisiologia , Comportamento Imitativo/fisiologia , Passeriformes/fisiologia , Acústica , Animais , Anuros , Bufonidae , América do Norte
20.
Dis Aquat Organ ; 135(3): 241-250, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31535619

RESUMO

Within communities, pathogens and parasites have the potential to indirectly influence predator-prey interactions. For instance, prey that exhibit pathology or altered traits (e.g. behavioral shifts) following infection could be more prone to predation, which is known as parasite-induced vulnerability to predation (PIVP). PIVP has been frequently documented for pathogens with trophic transmission, because predators are often critical in the pathogen's life cycle. However, for pathogens without trophic transmission, PIVP can lead to a healthy herds effect, thereby reducing transmission in the system. In this study, we explored whether the pathogen ranavirus (family Iridoviridae) enhances vulnerability of 4 species of larval amphibians (spring peepers Pseudacris crucifer, gray treefrogs Hyla versicolor, American toads Anaxyrus americanus, and northern leopard frogs Lithobates pipiens) to 2 common tadpole predators (larval green darners Anax junius [hereinafter Anax] and adult water bugs Belostoma flumineum [hereinafter Belostoma]). For each anuran species, we conducted short-term microcosm experiments to assess predation rates on individuals that were or were not exposed to virus. For 3 of the 4 species, we found that exposure to ranavirus decreased survival rates with Anax between 2- and 9-fold. However, we did not see the same trend with Belostoma, which indicates that predator identity is important in this interaction. More specifically, the higher efficiency of Anax in capturing and consuming prey, relative to Belostoma, may allow Anax to capitalize on trait changes induced by virus exposure and enhance the PIVP effect. Our results indicate that trait-mediated indirect effects could play a role in creating healthy herds in amphibian communities.


Assuntos
Anuros/parasitologia , Animais , Bufonidae , Larva , Comportamento Predatório
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