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1.
Parasitol Int ; 86: 102474, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34597760

RESUMO

We found juveniles of Paragonimus in the urinary bladder of a Japanese toad (Bufo japonicus formosus) captured in Kyoto. These were molecularly identified as Paragonimus skrjabini miyazakii Kamo, Nishida, Hatsushika et Tomimura 1961. This is the first report of P. s. miyazakii found in anuran hosts in Japan, indicating that anurans can be paratenic hosts of P. s. miyazakii, as is also the case for Paragonimus skrjabini skrjabini in China. This finding suggests that definitive hosts of P. s. miyazakii can be infected by eating not only crabs or mammal paratenic hosts, but also anurans.


Assuntos
Bufonidae , Paragonimíase/veterinária , Paragonimus/isolamento & purificação , Bexiga Urinária/parasitologia , Animais , Japão , Masculino , Paragonimíase/parasitologia
2.
Zhongguo Zhong Yao Za Zhi ; 46(18): 4774-4781, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34581088

RESUMO

Indolealkylamines(IAAs) are the main hydrophilic substances in toad skin, mainly including free N-methyl-5-hydroxytryptamine, bufotenine, bufotenidine, dehydrobufotenine, and binding bufothionine. In this study, the LPS-activated neutrophils were used to investigate the structure-activity relationship and anti-inflammatory mechanism of the above-mentioned five monomers from the toad skin in vitro. The neutrophils were divided into the control group, model group(1 µg·mL~(-1) LPS), positive drug group(100 µg·mL~(-1) indometacin), as well as the low-(50 µg·mL~(-1)), medium-(100 µg·mL~(-1)) and high-dose(200 µg·mL~(-1)) free N-methyl-5-hydroxytryptamine, bufotenine, bufotenidine, dehydrobufotenine, and binding bufothionine groups. The levels of IL-6, TNF-α and IL-1ß in the neutrophil supernatant of each group was measured by enzyme-linked immunosorbent assay(ELISA) after LPS stimulation, followed by the detection of apoptosis in each group after Annexin V/PI staining. The protein expression levels of caspase-3, Bax, Bcl-2, beclin1, LC3-I, and LC3-Ⅱ were assayed by Western blot. The results showed that IAAs reduced the excessive secretion of inflammatory cytokines caused by LPS compared with the model group. Besides, the activity of each free IAAs(N-methyl-5-hydroxytryptamine, bufotenine, bufotenidine and dehydrobufotenine), especially bufotenine, was stronger than that of the binding bufothionine. As revealed by Annexin V/PI staining, LPS delayed the early apoptosis of neutrophils compared with the control group, while bufotenine promoted the apoptosis of neutrophils in a dose-dependent manner, which might be related to the elevated expression of apoptosis-related protein Bax/Bcl-2. In addition, LPS activated the autophagy pathways in neutrophils. This study confirmed the efficacy of IAAs in reducing the secretion of inflammatory cytokines in neutrophils induced by LPS for the first time. For instance, bufotenine exerts the anti-inflammatory effect possibly by inducing the apoptosis of neutrophils.


Assuntos
Lipopolissacarídeos , Neutrófilos , Animais , Anti-Inflamatórios/farmacologia , Apoptose , Bufonidae , Lipopolissacarídeos/toxicidade , Pele
3.
J Biol Phys ; 47(3): 287-300, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34515919

RESUMO

Vertebrate hearts have undergone marked morphological and structural changes to adapt to different environments and lifestyles as part of the evolutionary process. Amphibians were the first vertebrates to migrate to land. Transition from aquatic to terrestrial environments required the ability to circulate blood against the force of gravity. In this study, we investigated the passive mechanical properties and histology of the ventricles of three species of Anura (frogs and toads) from different habitats, Xenopus laevis (aquatic), Pelophylax nigromaculatus (semiaquatic), and Bufo japonicus formosus (terrestrial). Pressure-loading tests demonstrated stiffer ventricles of P. nigromaculatus and B. j. formosus compared X. laevis ventricles. Histological analysis revealed a remarkable difference in the structure of cardiac tissue: thickening of the compact myocardium layer of P. nigromaculatus and B. j. formosus and enrichment of the collagen fibers of B. j. formosus. The amount of collagen fibers differed among the species, as quantitatively confirmed by second-harmonic generation light microscopy. No significant difference was observed in cardiomyocytes isolated from each animal, and the sarcomere length was almost the same. The results indicate that the ventricles of Anura stiffen during adaptation to life on land.


Assuntos
Anuros , Bufonidae , Animais , Evolução Biológica , Ecossistema , Xenopus laevis
4.
Proc Biol Sci ; 288(1957): 20211402, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34403634

RESUMO

The eyes of frogs and toads (Anura) are among their most fascinating features. Although several pupil shapes have been described, the diversity, evolution, and functional role of the pupil in anurans have received little attention. Studying photographs of more than 3200 species, we surveyed pupil diversity, described their morphological variation, tested correlation with adult habits and diel activity, and discuss major evolutionary patterns considering iris anatomy and visual ecology. Our results indicate that the pupil in anurans is a highly plastic structure, with seven main pupil shapes that evolved at least 116 times during the history of the group. We found no significant correlation between pupil shape, adult habits, and diel activity, with the exception of the circular pupil and aquatic habits. The vertical pupil arose at least in the most-recent common ancestor of Anura + Caudata, and this morphology is present in most early-diverging anuran clades. Subsequently, a horizontal pupil, a very uncommon shape in vertebrates, evolved in most neobatrachian frogs. This shape evolved into most other known pupil shapes, but it persisted in a large number of species with diverse life histories, habits, and diel activity patterns, demonstrating a remarkable functional and ecological versatility.


Assuntos
Evolução Biológica , Pupila , Animais , Anuros , Bufonidae , Filogenia
5.
Zhongguo Zhong Yao Za Zhi ; 46(14): 3529-3539, 2021 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-34402275

RESUMO

Bufonis Venenum,the dried secretion of Bufo bufo gargarizans or B. melanostictus,is toxic and hard with the efficacy of removing toxicity for detumescence and relieving pain. The processing of Bufonis Venenum dates back to the Song dynasty. In addition to the wine-processing,milk-processing and talcum powder-processing,there were some other kinds of processing methods in ancient times,such as baking,calcining,water-soaking and vinegar-processing. Modern studies have shown that the Bufonis Venenum has the main chemical components of bufadienolides,indole alkaloids sterols,and other compounds. It has the pharmacological effects of antitumor,cardiac,antibacterial,and analgesic activities,local anesthesia,and so on. This paper reviews the processing evolution,chemical components and pharmacological effects of Bufonis Venenum,providing references for its special processing and modern research as well as the theoretical basis for the research on its processing mechanism and quality control.


Assuntos
Bufanolídeos , Animais , Bufanolídeos/farmacologia , Bufonidae , Controle de Qualidade
6.
Environ Pollut ; 287: 117638, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34426379

RESUMO

Amphibian larvae are commonly used as indicators of aquatic ecosystem health because they are susceptible to contaminants. However, there is limited information on how species characteristics and trophic position influence contaminant loads in larval amphibians. Importantly, there remains a need to understand whether grazers (frogs and toads [anurans]) and predators (salamanders) provide comparable information on contaminant accumulation or if they are each indicative of unique environmental processes and risks. To better understand the role of trophic position in contaminant accumulation, we analyzed composite tissues for 10 metals from larvae of multiple co-occurring anuran and salamander species from 20 wetlands across the United States. We examined how metal concentrations varied with body size (anurans and salamanders) and developmental stage (anurans) and how the digestive tract (gut) influenced observed metal concentrations. Across all wetlands, metal concentrations were greater in anurans than salamanders for all metals tested except mercury (Hg), selenium (Se), and zinc (Zn). Concentrations of individual metals in anurans decreased with increasing weight and developmental stage. In salamanders, metal concentrations were less correlated with weight, indicating diet played a role in contaminant accumulation. Based on batches of similarly sized whole-body larvae compared to larvae with their digestive tracts removed, our results indicated that tissue type strongly affected perceived concentrations, especially for anurans (gut represented an estimated 46-97% of all metals except Se and Zn). This suggests the reliability of results based on whole-body sampling could be biased by metal, larval size, and development. Overall, our data shows that metal concentrations differs between anurans and salamanders, which suggests that metal accumulation is unique to feeding behavior and potentially trophic position. To truly characterize exposure risk in wetlands, species of different life histories, sizes and developmental stages should be included in biomonitoring efforts.


Assuntos
Ecossistema , Metais , Animais , Bufonidae , Larva , Reprodutibilidade dos Testes
7.
Molecules ; 26(14)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34299492

RESUMO

Toads in the family Bufonidae contain bufadienolides in their venom, which are characterized by their chemical diversity and high pharmacological potential. American trypanosomiasis is a neglected disease that affects an estimated 8 million people in tropical and subtropical countries. In this research, we investigated the chemical composition and antitrypanosomal activity of toad venom from Rhinella alata collected in Panama. Structural determination using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy led to the identification of 10 bufadienolides. Compounds identified include the following: 16ß-hydroxy-desacetyl-bufotalin-3-adipoyl-arginine ester (1), bufotalin (2), 16ß-hydroxy-desacetyl-bufotalin-3-pimeloyl-arginine ester (3), bufotalin-3-pimeloyl-arginine ester (4), 16ß-hydroxy-desacetyl-bufotalin-3-suberoyl-arginine ester (5), bufotalin-3-suberoyl-arginine ester (6), cinobufagin-3-adipoyl-arginine ester (7), cinobufagin-3-pimeloyl-arginine ester (8), cinobufagin-3-suberoyl-arginine ester (9), and cinobufagin (10). Among these, three new natural products, 1, 3, and 5, are described, and compounds 1-10 are reported for the first time in R. alata. The antitrypanosomal activity assessed in this study revealed that the presence of an arginyl-diacid attached to C-3, and a hydroxyl group at C-14 in the structure of bufadienolides that is important for their biological activity. Bufadienolides showed cytotoxic activity against epithelial kidney Vero cells; however, bufagins (2 and 10) displayed low mammalian cytotoxicity. Compounds 2 and 10 showed activity against the cancer cell lines MCF-7, NCI-H460, and SF-268.


Assuntos
Antiprotozoários/farmacologia , Bufanolídeos/farmacologia , Bufonidae/metabolismo , Pele/metabolismo , Venenos de Anfíbios/metabolismo , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Chlorocebus aethiops , Humanos , Células MCF-7 , Espectrometria de Massas/métodos , Panamá , Trypanosoma cruzi , Células Vero
8.
PLoS One ; 16(7): e0254439, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264969

RESUMO

Chytridiomycosis, a disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been linked with the disappearance of amphibian populations worldwide. Harlequin toads (Atelopus) are among the most severely impacted genera. Two species are already considered extinct and most of the others are at high risk of extinction. The recent rediscovery of harlequin toad populations coexisting with Bd suggest that the pathogen can maintain enzootic cycles at some locations. The mechanisms promoting coexistence, however, are not well understood. We explore the dynamics of Bd infection in harlequin toads by modeling a two-stage host population with transmission through environmental reservoirs. Simulations showed that variations in the recruitment of adults and the persistence of zoospores in the environment were more likely to drive shifts between extinction and coexistence than changes in the vulnerability of toads to infection with Bd. These findings highlight the need to identify mechanisms for assuring adult recruitment or minimizing transmission from potential reservoirs, biotic or abiotic, in recovering populations.


Assuntos
Bufonidae , Animais , Batrachochytrium , Quitridiomicetos , Micoses
9.
J Comp Physiol B ; 191(4): 765-776, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34089366

RESUMO

The metabolic cold adaptation (MCA) hypothesis predicts an increase in metabolic rate and thermal sensitivity of poikilotherms from cold environments as compared to those from warm environments, when measured under standardized conditions. This compensatory response is also expected to evolve in life history and behavioral traits if the reductions in these phenotypic traits at low temperature involves in a reduction in fitness. We investigated the extent to which the level of energy intake (measured as feeding rate), energy turnover (measured as standard metabolic rate, SMR) and the energy budget (energy allocation to growth and physical activity) are influenced by climatic conditions in three populations of the Asiatic toad (Bufo gargarizans) distributed across an altitudinal gradient of 1350 m in the Qionglai Mountains of Western China. We found a similar thermal reaction norm of SMR at both population and individual levels; therefore, the data did not support the MCA hypothesis. However, there was a co-gradient variation (CoGV) for mass change rate in which the high and medium altitudinal populations displayed slower mass change rates than their counterparts from low altitudes. Moreover, this CoGV pattern was accompanied by a low feeding rate and high physical activity for the high- and medium-altitude populations. Our results highlight that adjustments in energy intake and energy allocation to behaviors, but not energy allocation to metabolism of maintenance, could act as an energetic strategy to accommodate the varied growth efficiency in Asiatic toads along an altitudinal gradient.


Assuntos
Altitude , Bufonidae , Animais , China , Temperatura Baixa , Fenótipo
10.
Dis Aquat Organ ; 145: 79-88, 2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34137378

RESUMO

Chytridiomycosis, an emergent infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), is considered one of the drivers of the current amphibian biodiversity loss. To inform endangered species conservation efforts, it is essential to improve our knowledge about the abiotic and biotic factors that influence Bd infection dynamics in the wild. Here, we analyzed variation of Bd infection in the redbelly toad Melanophryniscus montevidensis, a threatened bufonid from Uruguay. We tested the influence of temperature, precipitation, season, and host population size on Bd prevalence and intensity. Additionally, considering the sub-lethal effects of Bd, we tested if these variables, potentially through their effect on Bd, also explain the variation in host body condition. We determined a high Bd prevalence of 41% (100/241), and that population size influenced both Bd prevalence and infection intensity. We identified an effect of precipitation and season on Bd infection intensity and an effect of season on toad body condition. In addition, we found a negative effect of infection intensity on body condition; moreover, while some toads cleared the infection, their body condition did not improve, suggesting a long-term cost. This is the first report on host population size as an important factor in Bd infection dynamics in a threatened anuran species, and seasonal demographic changes appear to play an important role in the dynamics. Finally, we highlight the need for monitoring Bd in this and other endangered amphibian populations, especially those within the genus Melanophryniscus, which includes several Endangered and Data Deficient species in South America.


Assuntos
Quitridiomicetos , Animais , Batrachochytrium , Bufonidae , Espécies em Perigo de Extinção , Estações do Ano , América do Sul , Uruguai/epidemiologia
11.
An Acad Bras Cienc ; 93(2): e20190470, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34105609

RESUMO

Determining both the age structure and growth pattern allows to establish the causal factors, environmental and/or genetic, that eventually may be responsible for the observed pattern of divergence. We examined the variation in age structure and growth pattern across populations of two toad species, Pelobates cultripes and Epidalea calamita that exhibit a geographic variation in body size in southern Spain. For both species, populations differed in mean age but age structure did not correlate with body size variation across populations. Although the population with the youngest females found for E. calamita was the smallest in body size, the oldest males for both species were found in a small body size population. The growth pattern fit well to a von Bertalanffy growth model and interdemic divergence were found for both the asymptotic body size (Sm ) and the growth coefficients (k). As expected, Large-Bodied populations of both species attained higher Sm but, Small-Bodied population had higher, although non significantly different, k growth coefficients. Also, the Small-Bodied population attained sexual maturity sooner but had also high longevity. The observed pattern may reflect both environmental variations in resources availability affecting body size observed across populations, but also different growth and maturity pathways that may respond to contrasting selective pressures.


Assuntos
Bufonidae , Longevidade , Animais , Tamanho Corporal , Feminino , Geografia , Masculino , Espanha
12.
Parasitol Int ; 84: 102400, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34052432

RESUMO

The amphibian acanthocephalan, Pseudoacanthocephalus toshimai, was considered to be an island-endemic species in Hokkaido, Japan. However, the parasite was found from Rana ornativentris, Rana tagoi, Zhangixalus arboreus, and Bufo japonicus formosus in northern Honshu (Aomori and Iwate Prefectures), which is separated from Hokkaido by the Tsugaru Strait. The mitochondrial DNA-based phylogenetic and population genetic analyses of P. toshimai showed that the northern Honshu isolates are far distantly related to the Hokkaido isolates, and that a demographic population expansion occurred in Hokkaido during the recent geological past. The rich genetic diversity of P. toshimai in northern Honshu suggests a scenario that anuran hosts invaded Hokkaido together with P. toshimai via the land bridge of the Tsugaru Strait. However, the evolutionary history of Rana pirica, a main definitive host for P. toshimai in Hokkaido, is contradictory to the introduction scenario inferred from the parasite. The finding of several geographically mismatched isolates of P. toshimai from both northern Honshu and Hokkaido suggests a possibility that the migration of the parasite infrequently occurred between the two areas even after the land bridge disappeared. More detailed information on the evolutionary history of anurans is needed to resolve the biogeographical enigma of P. toshimai.


Assuntos
Acantocéfalos/fisiologia , Distribuição Animal , Bufonidae/parasitologia , Interações Hospedeiro-Parasita , Ranidae/parasitologia , Acantocéfalos/classificação , Acantocéfalos/genética , Animais , DNA de Helmintos/análise , DNA Mitocondrial/análise , Japão , Filogeografia
13.
PLoS One ; 16(5): e0251027, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33956885

RESUMO

Ecuador is one of the most biodiverse countries in the world, but faces severe pressures and threats to its natural ecosystems. Numerous species have declined and require to be objectively evaluated and quantified, as a step towards the development of conservation strategies. Herein, we present an updated National Red List Assessment for amphibian species of Ecuador, with one of the most detailed and complete coverages for any Ecuadorian taxonomic group to date. Based on standardized methodologies that integrate taxonomic work, spatial analyses, and ecological niche modeling, we assessed the extinction risk and identified the main threats for all Ecuadorian native amphibians (635 species), using the IUCN Red List Categories and Criteria. Our evaluation reveals that 57% (363 species) are categorized as Threatened, 12% (78 species) as Near Threatened, 4% (26 species) as Data Deficient, and 27% (168 species) as Least Concern. Our assessment almost doubles the number of threatened species in comparison with previous evaluations. In addition to habitat loss, the expansion of the agricultural/cattle raising frontier and other anthropogenic threats (roads, human settlements, and mining/oil activities) amplify the incidence of other pressures as relevant predictors of ecological integrity. Potential synergic effects with climate change and emergent diseases (apparently responsible for the sudden declines), had particular importance amongst the threats sustained by Ecuadorian amphibians. Most threatened species are distributed in montane forests and paramo habitats of the Andes, with nearly 10% of them occurring outside the National System of Protected Areas of the Ecuadorian government. Based on our results, we recommend the following actions: (i) An increase of the National System of Protected Areas to include threatened species. (ii) Supporting the ex/in-situ conservation programs to protect species considered like Critically Endangered and Endangered. (iii) Focalizing research efforts towards the description of new species, as well as species currently categorized as Data Deficient (DD) that may turn out to be threatened. The implementation of the described actions is challenging, but urgent, given the current conservation crisis faced by amphibians.


Assuntos
Anfíbios , Espécies em Perigo de Extinção , Animais , Anuros , Bufonidae , Conservação dos Recursos Naturais/métodos , Bases de Dados como Assunto , Ecossistema , Equador , Espécies em Perigo de Extinção/estatística & dados numéricos
14.
J Exp Zool A Ecol Integr Physiol ; 335(6): 541-551, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34018702

RESUMO

The inflammatory response is a complex process that relies on interactions among multiple endocrine and immune modulators. Studies incorporating time-related and integrative endocrine and immune responses to an immune challenge might shed light on the characterization of the phases of the inflammatory response in anurans. The present study investigated time-related changes (1, 3, 6, and 18 h post-challenge) in plasma corticosterone (CORT), melatonin (MEL) and testosterone (T) levels, phagocytosis percentage (PP), plasma bacterial killing ability (BKA), and neutrophil to lymphocyte ratio (NLR) following a lipopolysaccharide (LPS) immune challenge in Rhinella diptycha toads. Our results showed the response to LPS injection was characterized by increased CORT, PP, BKA, and NLR, with a concomitant decrease in plasma MEL and T. Increased CORT was more pronounced at 6 and 18 h, while increased NLR was observed only 18 h post-LPS injection. Meanwhile, plasma MEL and T decreased independently of the time post-LPS injection. Additionally, toads in better body condition showed higher BKA and PP in the LPS-treated group, regardless of the time postinjection. Our results show that toads (R. diptycha) were sensitive to the LPS challenge, mounting an inflammatory response, which started quickly (after 1 h) and developed over time and was influenced by body condition. These results demonstrate a time-related hormonal and immune variation as a consistent pattern of activation of the immune system, as well as of hypothalamic-pituitary-adrenal/interrenal and immune-pineal axes following an immune challenge more deeply studied in mammals, suggesting the evolutionary conservation of the regulatory mechanisms for tetrapod vertebrates.


Assuntos
Bufonidae/imunologia , Corticosterona/sangue , Imunomodulação/efeitos dos fármacos , Lipopolissacarídeos/toxicidade , Melatonina/sangue , Animais , Atividade Bactericida do Sangue , Inflamação/induzido quimicamente , Inflamação/imunologia , Linfócitos/fisiologia , Masculino , Neutrófilos/fisiologia , Fagocitose , Testosterona/sangue
15.
Mol Phylogenet Evol ; 162: 107184, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33932615

RESUMO

African amphibian diversity remains underestimated with many cryptic lineages awaiting formal description. An important hotspot of amphibian diversification is the Guineo-Congolian rainforest in Central Africa, its richness attributable to present day and ancestral range fragmentation through geological barriers, habitat expansion and contraction, and the presence of steep ecological gradients. The charismatic Nectophryne tree toads present an interesting case study for diversification in this region. The two formally described species comprising this genus show nearly identical geographic distributions extending across most of the Guineo-Congolian rainforest, but show little morphological disparity. Both species harbour extensive genetic diversity warranting taxonomic revisions, and interestingly, when comparing the subclades within each, the two species show remarkably parallel diversification histories, both in terms of timing of phylogenetic splits and their geographic distributions. This indicates that common processes may have shaped the evolutionary history of these lineages.


Assuntos
Bufonidae/genética , Filogenia , Filogeografia , Floresta Úmida , Animais , Feminino , Masculino
16.
Environ Pollut ; 285: 117344, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34049135

RESUMO

Large-scale ecotoxicological studies have technical and ethical limitations, both related to the need to expose large numbers of individuals to potentially harmful compounds. The computational modeling is a complementary useful and predictive tool that overcomes these limitations. Considering the increasing interest in the effects of pesticides on behavioral traits, the aim of this study was to evaluate the effects of chlorpyrifos (CPF) on intra- and inter-specific interactions of anuran tadpoles, complementing traditional ecotoxicological tools with a theoretical analysis verified by computational simulations. Experiments were developed under two consecutive phases: a first phase of exposure (treated and control group), and a second phase of interactions. The second phase consisted of evaluating the effects of CPF on intra- and inter-specific interactions of exposed C. ornata (Co) tadpoles acting as predators and unexposed Rhinella fernandezae (Rf) tadpoles acting as prey (Experiment I), under different predator-prey proportions (0/10 = 0Co-10Rf, 2/8, 4/6, 6/4, 8/2, 10/0). Also, intraspecific interactions of three Co tadpoles under different conditions of exposure were evaluated (Experiment II: 3 exposed Co, 2 exposed Co/1 non-exposed, 1 exposed Co/2 non-exposed). During the exposure phase, chlorpyrifos induced significant mortality from 48 h (48 h: p < 0.05, 72 h-96 h: p < 0.001), irregular swimming, tail flexure, and the presence of subcutaneous air. Also, it induced effects on the sounds emitted after 96 h of exposure, registering a smaller number of pulses and higher dominant frequencies, and altered intra- and inter-specific interactions. During the interaction phase, the larvae continued to show sound effects, however, the antipredator mechanism continued to be operating and efficient. Finally, it was possible to model the behavior of the larvae under the effects of chlorpyrifos. We conclude that experimental data and computational modeling matched. Therefore, computational simulation is a valuable ecotoxicological tool that provides new information and allows prediction of natural processes.


Assuntos
Clorpirifos , Animais , Anuros , Bufonidae , Clorpirifos/toxicidade , Ecotoxicologia , Humanos , Larva , Comportamento Predatório
17.
Vet Pathol ; 58(4): 713-729, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33813961

RESUMO

A comparative study was carried out on common and agile frogs (Rana temporaria and R. dalmatina) naturally infected with ranid herpesvirus 3 (RaHV3) and common toads (Bufo bufo) naturally infected with bufonid herpesvirus 1 (BfHV1) to investigate common pathogenetic pathways and molecular mechanisms based on macroscopic, microscopic, and ultrastructural pathology as well as evaluation of gene expression. Careful examination of the tissue changes, supported by in situ hybridization, at different stages of development in 6 frogs and 14 toads revealed that the skin lesions are likely transient, and part of a tissue cycle necessary for viral replication in the infected hosts. Transcriptomic analysis, carried out on 2 naturally infected and 2 naïve common frogs (Rana temporaria) and 2 naturally infected and 2 naïve common toads (Bufo bufo), revealed altered expression of genes involved in signaling and cell remodeling in diseased animals. Finally, virus transcriptomics revealed that both RaHV3 and BfHV1 had relatively high expression of a putative immunomodulating gene predicted to encode a decoy receptor for tumor necrosis factor in the skin of the infected hosts. Thus, the comparable lesions in infected frogs and toads appear to reflect a concerted epidermal and viral cycle, with presumptive involvement of signaling and gene remodeling host and immunomodulatory viral genes.


Assuntos
Infecções por Herpesviridae , Herpesviridae , Dermatopatias , Animais , Anuros , Bufonidae , Herpesviridae/genética , Infecções por Herpesviridae/veterinária , Dermatopatias/veterinária
18.
J Anim Ecol ; 90(8): 1878-1890, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33884620

RESUMO

The unidirectional movement of animals between breeding patches (i.e. breeding dispersal) has profound implications for the ecological and evolutionary dynamics of spatially structured populations. In spatiotemporally variable environments, individuals are expected to adjust their dispersal decisions according to information gathered on the environmental and/or social cues that reflect the fitness prospects in a given breeding patch (i.e. informed dispersal). A paucity of empirical work limited our understanding of the ability of animals to depart from low-quality breeding patches and settle in high-quality breeding patches. We examined the capacity of individuals to respond to stochastic changes in habitat quality via informed breeding dispersal in a pond-breeding amphibian. We conducted a 5-year (2015-2019) capture-recapture study of boreal toads Anaxyrus boreas boreas (n = 1,100) that breed in beaver ponds in western Wyoming, USA. During early spring of 2017, an extreme flooding event destroyed several beaver dams and resulted in the loss of breeding habitat. We used multi-state models to investigate how temporal changes in pond characteristics influenced breeding dispersal, and determine whether movement decisions were in accordance with prospects for reproductive fitness. Boreal toads more often departed from low-quality breeding ponds (without successful metamorphosis) and settled in high-quality breeding ponds (with successful metamorphosis). Movement decisions were context-dependent and associated with pond characteristics altered by beaver dam destruction. Individuals were more likely to depart from shallow ponds with high vegetation cover and settle in deep ponds with low vegetation cover. The probability of metamorphosis was related to the same environmental cues, suggesting that boreal toads assess the fitness prospects of a breeding patch and adjust movement decisions accordingly (i.e. informed breeding dispersal). We demonstrated that stochastic variability in environmental conditions and habitat quality can underpin dispersal behaviour in amphibians. Our study highlighted the mechanistic linkages between habitat change, movement behaviour and prospects for reproductive performance, which is critical for understanding how wild animals respond to rapid environmental change.


Assuntos
Ecossistema , Lagoas , Animais , Bufonidae , Reprodução , Wyoming
19.
Zool Res ; 42(3): 272-279, 2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-33797210

RESUMO

A new species of the genus Atelopus, Atelopus fronterizo sp. nov., from eastern Panama is described herein based on molecular, morphological, and bioacoustic evidence. The new species can be distinguished from its congeners occurring in the region by a combination of the following characters: (1) phalangeal reduction in thumb; (2) SVL (females only) (35.1-50.1; n=13), HW/SVL (0.23-0.34; n=59), EYND/HW (0.27-0.39; n=60), TIBL/SVL (0.41-0.56; n=58), and HAL/SVL (0.22-0.28; n=49); (3) dorsal color pattern with green or yellow background and extensive dark olive blotches forming transversal bands or mottling; (4) advertisement call duration 176-235 ms with 19-34 pulses, average pulse rate 131.69 pulses/s, and dominant frequency 2 422.50-2 606.50 Hz. The new species is nested within the Central American clade of Atelopus. The minimum Kimura-2-parameter (K2P) genetic divergence between Atelopus fronterizo sp. nov. and its most phylogenetically similar congeners ( A. certus and A. glyphus) is >2.6% for 16S and >4.9% for COI (Table 1). The phylogenetic relationship is strongly supported by ultrafast bootstrap values for the maximum-likelihood trees of both genetic markers (16S, 96; COI, 100, Figure 1A). Bayesian analysis of the concatenated sequences resulted in a tree with similar topology and high posterior probability support (0.99; Supplementary Figure S1). In addition, haplotype networks inferred from COI and 16S (Supplementary Figure S2) showed a well-separated clade containing the new species (two for COI, four for 16S). The number of mutational steps between haplotypes for the new species samples is very low (1-4 in 16S; one in COI), and the minimum number of mutational steps from the nearest species is nine for 16S (distance to A. certus) and 28 for COI (distance to A. glyphus).


Assuntos
Bufonidae/classificação , Bufonidae/genética , Distribuição Animal , Animais , Panamá , Filogenia , Especificidade da Espécie
20.
J Comp Pathol ; 183: 45-50, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33714431

RESUMO

An 11-year-old captive, female Houston toad (Anaxyrus houstonensis) became lethargic and reluctant to move. This toad had been administered human chorionic gonadotropin (HCG) and luteinizing hormone-releasing hormone (LHRH) annually as part of a hormone-assisted captive propagation programme for 8 years. Due to poor prognosis, euthanasia was elected. At necropsy, the liver was moderately enlarged, diffusely dark red and had a nodular superficial appearance. Microscopically, the hepatic nodules consisted of poorly demarcated, non-encapsulated, paucicellular infiltrative neoplastic growths. These consisted of spindle cells, similar to sinusoidal endothelial cells, that formed irregular blood-filled vascular channels resembling sinusoids separated by thin bands of collagen and reticulin fibres. Neoplastic cells dissected through and replaced hepatic cords and bile ducts. Based on the cytohistomorphological features and analogy with vascular neoplasms in other vertebrates, a diagnosis of low-grade angiosarcoma was made. To the best of our knowledge, this is the first record of primary hepatic vascular neoplasia in an amphibian. It is not known if the long-term administration of HCG and LHRH had any oncogenic role in this animal. Vascular neoplasia should be included in the differential diagnosis of hepatomegaly and non-specific lethargy and health decline in amphibian species.


Assuntos
Bufonidae , Neoplasias Vasculares , Animais , Gonadotropina Coriônica , Células Endoteliais , Evolução Fatal , Feminino , Hormônio Liberador de Gonadotropina , Fígado/irrigação sanguínea , Fígado/patologia , Neoplasias Vasculares/veterinária
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