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1.
Amino Acids ; 54(2): 181-192, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34738177

RESUMO

The use of acetylcholinesterase (AChE) inhibitors, antioxidants or multitarget compounds are among the main strategies against Alzheimer's disease (AD). Between AChE inhibitors, those targeting the peripheral anionic site (PAS) are of special interest. Here, we describe the rational design and synthesis of peptide analogs of a natural PAS-targeting sequence that we recently discovered, aiming at increasing its activity against AChE. We also tested their radical scavenging and metal chelating properties. Our design strategy was based on the position-specific, computer-aided insertion of aromatic residues. The analog named as W3 showed a 30-fold higher inhibitory activity than the original sequence and an improved antioxidant activity. W3 is the most potent modified natural peptide against Electrophorus electricus AChE ever reported with an IC50 of 10.42 µM (± 1.02). In addition, it showed a radical scavenging activity of 47.00% ± 3.11 at 50 µM and 93.47% ± 1.53 at 400 µM. Since peptides are receiving increasing interest as drugs, we propose the W3 analog as an attractive sequence for the development of new peptide-based multitarget drugs for AD. Besides, this work sheds light on the importance of the aromatic residues in the modulation of AChE activity and their effect on the radical scavenging activity of a peptide.


Assuntos
Doença de Alzheimer , Inibidores da Colinesterase , Acetilcolinesterase/metabolismo , Doença de Alzheimer/tratamento farmacológico , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Anuros/metabolismo , Inibidores da Colinesterase/química , Simulação de Acoplamento Molecular , Peptídeos/farmacologia , Relação Estrutura-Atividade
2.
An Acad Bras Cienc ; 94(2): e20210282, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35507981

RESUMO

Our objective was to describe and compare the diet of endemic anurans of the Atlantic Forest, as well as to evaluate the influence of biotic factors on the trophic ecology of the species. We conducted the study in Mananciais da Serra (Piraquara-PR), a transition region between mixed and dense ombrophilous forest, between January 2019 and February 2020. In this work, we describe the diet of eight species: Aplastodiscus albosignatus, Boana semiguttata, Bokermannohyla circumdata, Ischnocnema henselii, Leptodactylus notoaktites, Proceratophrys boiei, Rhinella abei and Scythrophrys sawayae. Coleoptera were important prey in the diet of most species, except for B. circumdata and L. notoaktites. All species showed potential selection for some category of prey. We observed a correlation between the size of the individuals and the volume of consumed prey in I. henselii. In general, the niche overlap between species was low, and most species had a broad trophic niche.


Assuntos
Anuros , Florestas , Animais , Brasil , Dieta/veterinária , Ecologia
3.
Dis Aquat Organ ; 149: 53-58, 2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35510821

RESUMO

Amphibians breeding in aquatic environments may encounter a myriad of threats during their life cycle. One species known to prey on native amphibians in aquatic habitats is the invasive North American bullfrog Lithobates catesbeianus, which, besides being a voracious predator and competitor, often acts as a pathogen carrier and disease superspreader because it tolerates high infection loads of the frog-killing fungus Batrachochytrium dendrobatidis (Bd). Here, we hypothesized that the presence of the bullfrogs in microcosms should either (1) decrease Bd disease severity in native frog species by discouraging them from using the aquatic environment, or (2) increase the mortality of the native species. We tested these 2 mutually exclusive hypotheses by co-housing the snouted treefrog Scinax x-signatus (native to our study area) with L. catesbeianus in the laboratory, exposing them to Bd, and using qPCR analysis to quantify the resulting Bd infection loads in the native frogs. Our experiment had the following replicated treatments: (1) native-only treatment (3 individuals of S. x-signatus), (2) native-predominant treatment (2 S. x-signatus + 1 L. catesbeianus), and (3) exotic-predominant treatment (1 S. x-signatus + 2 L. catesbeianus). We found that Bd infection loads in the native S. x-signatus were highest in the native-only treatment, and lowest in the exotic-predominant treatment, indicating that bullfrogs may discourage native frogs from occupying the aquatic habitat, thus reducing encounter rates between native frogs and the waterborne pathogen. This effect could be driven by the bullfrogs' predatory behavior and their high philopatry to aquatic habitats. Our results highlight that predation risk adds to the complexity of host-species interactions in Bd epidemiology.


Assuntos
Quitridiomicetos , Doenças Transmissíveis , Micoses , Animais , Anuros/microbiologia , Doenças Transmissíveis/veterinária , Micoses/microbiologia , Micoses/veterinária , Rana catesbeiana/microbiologia , Estados Unidos
4.
Genes (Basel) ; 13(4)2022 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-35456381

RESUMO

We used genotyping-by-sequencing (GBS) to identify sex-linked markers in 43 wild-collected spiny frog (Quasipaa boulengeri) adults from a single site. We identified a total of 1049 putatively sex-linked GBS-tags, 98% of which indicated an XX/XY system, and finally confirmed 574 XY-type sex-linked loci. The sex specificity of five markers was further validated by PCR amplification using a large number of additional individuals from 26 populations of this species. A total of 27 sex linkage markers matched with the Dmrt1 gene, showing a conserved role in sex determination and differentiation in different organisms from flies and nematodes to mammals. Chromosome 1, which harbors Dmrt1, was considered as the most likely candidate sex chromosome in anurans. Five sex-linked SNP makers indicated sex reversals, which are sparsely present in wild amphibian populations, in three out of the one-hundred and thirty-three explored individuals. The variety of sex-linked markers identified could be used in population genetics analyses requiring information on individual sex or in investigations aimed at drawing inferences about sex determination and sex chromosome evolution.


Assuntos
Ranidae , Cromossomos Sexuais , Animais , Anuros/genética , Ligação Genética , Genótipo , Mamíferos/genética , Ranidae/genética , Cromossomos Sexuais/genética
5.
J Mol Model ; 28(5): 128, 2022 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-35461388

RESUMO

In COVID-19 infection, the SARS-CoV-2 spike protein S1 interacts to the ACE2 receptor of human host, instigating the viral infection. To examine the competitive inhibitor efficacy of broad spectrum alpha helical AMPs extracted from frog skin, a comparative study of intermolecular interactions between viral S1 and AMPs was performed relative to S1-ACE2p interactions. The ACE2 binding region with S1 was extracted as ACE2p from the complex for ease of computation. Surprisingly, the Spike-Dermaseptin-S9 complex had more intermolecular interactions than the other peptide complexes and importantly, the S1-ACE2p complex. We observed how atomic displacements in docked complexes impacted structural integrity of a receptor-binding domain in S1 through conformational sampling analysis. Notably, this geometry-based sampling approach confers the robust interactions that endure in S1-Dermaseptin-S9 complex, demonstrating its conformational transition. Additionally, QM calculations revealed that the global hardness to resist chemical perturbations was found more in Dermaseptin-S9 compared to ACE2p. Moreover, the conventional MD through PCA and the torsional angle analyses indicated that Dermaseptin-S9 altered the conformations of S1 considerably. Our analysis further revealed the high structural stability of S1-Dermaseptin-S9 complex and particularly, the trajectory analysis of the secondary structural elements established the alpha helical conformations to be retained in S1-Dermaseptin-S9 complex, as substantiated by SMD results. In conclusion, the functional dynamics proved to be significant for viral Spike S1 and Dermaseptin-S9 peptide when compared to ACE2p complex. Hence, Dermaseptin-S9 peptide inhibitor could be a strong candidate for therapeutic scaffold to prevent infection of SARS-CoV-2.


Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2 , Animais , Anuros/metabolismo , COVID-19/tratamento farmacológico , Humanos , Peptídeos/metabolismo , Ligação Proteica , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/metabolismo
6.
An Acad Bras Cienc ; 94(1): e20200092, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35442263

RESUMO

Intending to increase the knowledge about cytogenetics of Physalaemus and the sparsely studied P. gracilis group, we analyzed the karyotypes of P. carrizorum, P. gracilis, P. lisei, and P. sp. aff. gracilis. We studied chromosome morphology, heterochromatin patterns, Ag-NORs location and mapped the repetitive DNA sequence PcP190. All species showed diploid karyotypes composed of 22 bi-armed chromosomes and similar C- bands and Ag-NOR patterns. C-bands were mainly centromeric and pericentromeric; non-centromeric C-bands were detected on the telomeres of pair 1 in P. lisei, although polymorphic, and interstitially on pair 10 of P. gracilis. This last character is useful to distinguish P. gracilis from its sibling species P. sp. aff. gracilis. The Ag-NOR sites were detected on the long arms of chromosome pair 8 but with a variable position among species. Clusters of PcP190 showed centromeric and pericentromeric positions coincident with conspicuous C-bands, on pairs 2 and 9 in P. gracilis and P. sp. aff. gracilis, pair 3 in P. carrizorum, and pair 7 in P. lisei. These results significantly increase the knowledge about Physalaemus cytogenetics and encourage further studies on the satellite PcP190 in other genera of Leiuperinae to better understand its taxonomic distribution and the evolutionary dynamics.


Assuntos
Anuros , Animais , Anuros/genética , Análise Citogenética , Citogenética , Cariótipo , Filogenia , Especificidade da Espécie
7.
Am Nat ; 199(5): 653-665, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35472015

RESUMO

AbstractTo thoroughly understand the drivers of dynamic signal elaboration requires assessing the direct and indirect effects of naturally interacting factors. Here, we use structural equation modeling to test multivariate data from in situ observations of sexual signal production against a model of causal processes hypothesized to drive signal elaboration. We assess direct and indirect effects, and relative impacts, of male-male competition and attacks by eavesdropping frog-biting midges (Diptera: Corethrellidae) on call elaboration of male túngara frogs (Engystomops pustulosus). We find that the intensity of attacks by these micropredator flies drives the extent to which frogs elaborate their calls, likely due to a temporal trade-off between signaling and antimicropredator defense. Micropredator attacks appear to dynamically limit a male's call rate and complexity and consequently dampen the effects of intrasexual competition. In accounting for naturally interacting drivers of signal elaboration, this study presents a counterpoint to the mechanisms traditionally thought to drive sexual selection in this system. Moreover, the results shed light on the relatively unexamined and potentially influential role of eavesdropping micropredators in the evolution of sexual communication systems.


Assuntos
Dípteros , Vocalização Animal , Animais , Anuros , Masculino , Comportamento Sexual Animal
8.
BMC Genomics ; 23(1): 296, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35410120

RESUMO

BACKGROUND: Acoustic communication is important for the survival and reproduction of anurans and masking background noise is a critical factor for their effective acoustic communication. Males of the concave-eared frog (Odorrana tormota) have evolved an ultrasonic communication capacity to avoid masking by the widespread background noise of local fast-flowing streams, whereas females exhibit no ultrasonic sensitivity. However, the molecular mechanisms underlying the high-frequency hearing differences between the sexes of O. tormota are still poorly understood. RESULTS: In this study, we sequenced the brain transcriptomes of male and female O. tormota, and compared their differential gene expression. A total of 4,605 differentially expressed genes (DEGs) between the sexes of O. tormota were identified and eleven of them were related to auditory based on the annotation and enrichment analysis. Most of these DEGs in males showed a higher expression trend than females in both quantity and expression quantity. The highly expressed genes in males were relatively concentrated in neurogenesis, signal transduction, ion transport and energy metabolism, whereas the up-expressed genes in females were mainly related to the growth and development regulation of specific auditory cells. CONCLUSIONS: The transcriptome of male and female O. tormota has been sequenced and de novo assembled, which will provide gene reference for further genomic studies. In addition, this is the first research to reveal the molecular mechanisms of sex differences in ultrasonic hearing between the sexes of O. tormota and will provide new insights into the genetic basis of the auditory adaptation in amphibians during their transition from water to land.


Assuntos
Ranidae , Transcriptoma , Animais , Anuros/fisiologia , Feminino , Perfilação da Expressão Gênica , Audição/fisiologia , Masculino
9.
Commun Biol ; 5(1): 347, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35411020

RESUMO

Large diversifications of species are known to occur unevenly across space and evolutionary lineages, but the relative importance of their driving mechanisms, such as climate, ecological opportunity and key evolutionary innovations (KEI), remains poorly understood. Here, we explore the remarkable diversification of rhacophorid frogs, which represent six percent of global amphibian diversity, utilize four distinct reproductive modes, and span a climatically variable area across mainland Asia, associated continental islands, and Africa. Using a complete species-level phylogeny, we find near-constant diversification rates but a highly uneven distribution of species richness. Montane regions on islands and some mainland regions have higher phylogenetic diversity and unique assemblages of taxa; we identify these as cool-wet refugia. Starting from a centre of origin, rhacophorids reached these distant refugia by adapting to new climatic conditions ('niche evolution'-dominant), especially following the origin of KEIs such as terrestrial reproduction (in the Late Eocene) or by dispersal during periods of favourable climate ('niche conservatism'-dominant).


Assuntos
Anuros , Reprodução , Animais , Anuros/genética , Ilhas , Filogenia , Filogeografia
10.
J Anim Ecol ; 91(4): 696-700, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35383925

RESUMO

IN FOCUS: Caldart, M. V., M. B. dos Santos & G. Machado (2021). Function of a multimodal signal: a multiple hypothesis test using a robot frog Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13620. Animals can communicate using signals perceived by different sensory systems, and many combine multiple sensory modalities in their display repertoires. Why these multimodal displays evolve and how they function to transmit information between individuals are crucial questions in behavioural and evolutionary research. Most empirical studies addressing these questions assume, even if implicitly, that signals of different modalities have independent effects on receiver responses. Nonetheless, the potential for interactions between signals as an explanation for the function of multimodal displays has been recognized for over two decades. Caldart et al. (2021) use a robotic frog and a receiver-based approach to test four alternative hypotheses for the function of multimodal (acoustic + visual) displays in the stream-dwelling frog Crossodactylus schmidti. Their results lend support to an inter-signal interaction mechanism, whereby inclusion of visual signals modifies the context in which an acoustic display is interpreted. In contrast, the results in Caldart et al. (2021) are less consistent with the hypotheses that emphasize the quality-related information encoded in different signal modalities and a hypothesis that focuses on signal transmission across heterogeneous environments. These results showcase how experimental manipulation of different signal modalities and tests of multiple alternative hypotheses are key to clarifying the function of multimodal displays.


Assuntos
Procedimentos Cirúrgicos Robóticos , Robótica , Animais , Anuros/fisiologia , Evolução Biológica
11.
Zootaxa ; 5093(2): 218-232, 2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35390806

RESUMO

We describe a new species of red-eyed frog of the genus Pristimantis from the tropical forest at elevations of 10001350 m on western slope of the Cordillera Occidental, department of Risaralda, Colombia. The new species differs from congeners by having dorsum skin shagreened with low tubercles; vocal sac single, median and subgular in males, iris red wine in females copper red in males, and by presenting black groin coloration with yellow light blotches. In addition, the new species has concave frontoparietals, an unusual character described in Brachycephaloidea frog species.


Assuntos
Anuros , Cyprinidae , Animais , Colômbia , Feminino , Florestas , Masculino , Filogenia
12.
Zootaxa ; 5104(2): 209-241, 2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35391040

RESUMO

The six species of mountain frogs (Philoria: Limnodynastidae: Anura) are endemic to south-eastern Australia. Five species occur in headwater systems in mountainous north-eastern New South Wales (NSW) and south-eastern Queensland (Qld), centred on the Gondwana Rainforests of Australia World Heritage Area. A previous molecular genetic analysis identified divergent genetic lineages in the central and western McPherson Ranges region of Qld and NSW, but sampling was inadequate to test the species status of these lineages. With more comprehensive geographic sampling and examination of the nuclear genome using SNP analysis, we show that an undescribed species, P. knowlesi sp. nov., occurs in the central and western McPherson Ranges (Levers Plateau and Mount Barney complex). The new species is not phylogenetically closely related to P. loveridgei in the nuclear data but is related to one of two divergent lineages within P. loveridgei in the mtDNA data. We postulate that the discordance between the nuclear and mtDNA outcomes is due to ancient introgression of the mtDNA genome from P. loveridgei into the new species. Male advertisement calls and multivariate morphological analyses do not reliably distinguish P. knowlesi sp. nov. from any of the Philoria species in northeast NSW and southeast Qld. The genetic comparisons also enable us to define further the distributions of P. loveridgei and P. kundagungan. Samples from the Lamington Plateau, Springbrook Plateau, Wollumbin (Mt Warning National Park), and the Nightcap Range, are all P. loveridgei, and its distribution is now defined as the eastern McPherson Ranges and Tweed caldera. Philoria kundagungan is distributed from the Mistake Mountains in south-eastern Qld to the Tooloom Scrub on the Koreelah Range, southwest of Woodenbong, in NSW, with two subpopulations identified by SNP analysis. We therefore assessed the IUCN threat category of P. loveridgei and P. kundagungan and undertook new assessments for each of its two subpopulations and for the new taxon P. knowlesi sp. nov., using IUCN Red List criteria. Philoria loveridgei, P. kundagungan (entire range and northern subpopulation separately) and P. knowlesi sp. nov. each meet criteria for Endangered (EN B2(a)(b)[i, iii]). The southern subpopulation of P. kundagungan, in the Koreelah Range, meets criteria for Critically Endangered (CE B2(a)(b)[i, iii]). These taxa are all highly threatened due to the small number of known locations, the restricted nature of their breeding habitat, and direct and indirect threats from climate change, and the potential impact of the amphibian disease chytridiomycosis. Feral pigs are an emerging threat, with significant impacts now observed in Philoria breeding habitat in the Mistake Mountains.


Assuntos
Anuros , Floresta Úmida , Animais , Anuros/genética , Austrália , DNA Mitocondrial/genética , Masculino , Filogenia
13.
Zootaxa ; 5100(4): 521-540, 2022 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-35391061

RESUMO

Pristimantis is the most diverse Neotropical genus of terrestrial vertebrates and is distributed from Central America to Argentina. The last few years have seen the description of several new species of the genus, suggesting that its diversity is still underestimated. After decades of uncertainties about the taxonomic status of populations of Pristimantis from the Brejos de Altitude of the state of Cear, Northeast Brazil, we finally found morphological, acoustic and molecular evidence confirming their distinctiveness from other Atlantic Forest species. The new species is characterized by the following: shagreen dorsal skin with small-scattered tubercles, absence of dorsolateral fold, presence of tarsal fold, advertisement call composed of 18 pulsed notes, (25 pulses per note), and dominant frequency located in the second energy band, ranging from 36174220 Hz. Phylogenetic analysis placed the new species in the Pristimantis conspicillatus species group and the sister lineage of the Atlantic Forest clade comprising P. ramagii, P. paulodutrai and the P. vinhai species complex.


Assuntos
Altitude , Anuros , Animais , Brasil , Florestas , Filogenia
14.
Zootaxa ; 5100(3): 419-434, 2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35391067

RESUMO

The aquatic frog genus Euphlyctis is now considered under two separate genera- Euphlyctis Fitzinger and Phrynoderma Fitzinger, with four valid species in each genus, respectively. The current distribution range of the genus Phrynoderma is restricted to peninsular India and Bangladesh, with a probability of availability in Sri Lanka. The genus Euphlyctis has a wide range of distribution from the Arabian Peninsula and the South Asian countries, with a few historical descriptions treated as junior synonyms of the species Euphlyctis cyanophlyctis in India. A new species of skittering frog, Euphlyctis jaladhara sp. nov. is described here from the surroundings of the Thattekad Bird Sanctuary of Kerala, India, which has a predominant distribution in the western coastal plains of peninsular India and some parts of the Western Ghats. The new species has distinct morphological characters and a high genetic distance that distinguishes it from the sympatric species. Discussions are made concerning the validity of the species E. ghoshi and E. kalasgramensis.


Assuntos
Anuros , Lepidópteros , Animais , Índia
18.
Zootaxa ; 5092(1): 116-126, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35391218

RESUMO

Limnonectes liui (Yang, 1983) is a poorly known frog from Yunnan Province, China, with a confusing taxonomic history. We use mitochondrial (mt) DNA sequence data from newly collected specimens to reconstruct the phylogenetic position of the species. Limnonectes liui was found to be deeply nested within the geographically widespread dicroglossid frog L. limborgi (Sclater, 1892), verifying its placement within the genus Limnonectes but casting doubt on its distinction as a species. Morphological comparisons of the holotype and newly collected specimens of L. liui to specimens of L. limborgi from across its range also corroborated the hypothesis that these two species are conspecific, and we recommend treating L. liui as a junior synonym of L. limborgi. Our study underscores the importance of making comparisons with species found beyond a countrys border when describing new species.


Assuntos
Anuros , Genes Mitocondriais , Animais , China , DNA Mitocondrial/genética , Filogenia
19.
Zootaxa ; 5092(1): 67-84, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35391221

RESUMO

The Terrarana frogs of the genus Pristimantis are acknowledged for their direct development into froglets and for their astonishing species richness, which renders it the anuran genus with the highest number of species. We describe a new species of Pristimantis from the northwestern Andes of Colombia. The species is distributed from an area between 2750-2900 m.a.s.l. in the Mesenia-Paramillo Nature Reserve. Pristimantis postducheminorum sp. nov. differs from other, phylogenetically related, or similar resembling Pristimantis taxa by a striking yellow coloration in the ventral area, dark grey coloration in the concealed surfaces of the thighs and groin, absence of nuptial pads, presence of lateral fringes on fingers, presence of vomerine odontophores triangular in shape from the ventral view, and absence of dorsolateral folds. Molecular phylogenetics place this new species close to P. satagius and therefore within the P. ridens species group. The new species is also phylogenetically close and sympatric with the recently described P. ferwerdai, which further indicates that the Pristimantis fauna has been notoriously underestimated in the Colombian western cloud forests, a fact that should be considered in assessments of environmental impact.


Assuntos
Anuros , Florestas , Animais , Colômbia , Filogenia
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