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1.
Zootaxa ; 5174(1): 25-45, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-36095413

RESUMO

Glandirana rugosa is known to include several geographic groups differing in sex chromosomes, and has been proven to be paraphyletic in mitochondrial phylogeny with respect to G. susurra. By analyzing genetic and morphological variation in a large number of individuals of Glandirana, we studied their taxonomic relationships. A mitochondrial DNA phylogeny, with the G. tientaiensis as outgroup, revealed two major lineages containing respectively (1) the East group of G. rugosa, G. susurra, and the Central and Southeast-Kyushu groups of G. rugosa; and (2) G. emeljanovi, and the North and West groups of G. rugosa. In contrast, in a nuclear DNA phylogeny based on SNP data, lineages of (1) G. susurra and East group, and (2) the remaining groups of G. rugosa and G. emeljanovi, were split, indicating a distinct status of the East group among G. rugosa. In adult morphology, there were only minor differences between the East group and the remaining groups of G. rugosa, but in larvae, the East group had significantly more sparse skin glands than the others. The exact type locality of G. rugosa is most probably in western Japan, not including the range of the East group. From these results, we describe the East group as a new species, G. reliquia, distinct from the remaining groups of G. rugosa. The new species with sexually homomorphic chromosomes is thought to represent a basic stock of Japanese Glandirana, which existed far before G. rugosa originated.


Assuntos
Ranidae , Cromossomos Sexuais , Animais , DNA Mitocondrial/genética , Filogenia , Ranidae/genética , Cromossomos Sexuais/genética
2.
Zootaxa ; 5150(4): 591-599, 2022 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-36095645

RESUMO

Frogs in the family Ranidae are diverse in Asia and are thought to have dispersed to the Sahul Shelf approximately 10 million years ago, where they radiated into more than a dozen species. Ranid species in the intervening oceanic islands of Wallacea, such as Hylarana florensis and H. elberti from the Lesser Sundas and H. moluccana from eastern Wallacea, are assumed to belong to the subgenus Papurana, yet this has not been confirmed with molecular data. We analyzed mitochondrial DNA of Hylarana species from five islands spanning the reported ranges of H. florensis and H. elberti and compared them to confirmed Papurana species and closely related subgenera within Hylarana. We find that the Lesser Sunda H. florensis and H. elberti form a clade that is sister to the rest of the Australo-Papuan Papurana assemblage. Species delimitation analyses and divergence time estimates suggest that populations of H. florensis on Lombok may be distinct from those on Flores at the species level. Likewise, populations of H. elberti on Sumba and Timor may be distinct from each other and from those on Wetar, tshe type locality of H. elberti. Samples from Babar Island thought to be members of H. elberti in fact belong to the wide-ranging H. daemeli, which occurs in northern Australia, across New Guinea, and on the neighboring island of Tanimbar. These results suggest that the Lesser Sundas may have served as a stepping-stone for colonization of the Sahul Shelf and that species diversity of Papurana frogs is underestimated in the Lesser Sundas.


Assuntos
DNA Mitocondrial , Ranidae , Animais , DNA Mitocondrial/genética , Filogenia , Ranidae/genética
3.
Oxid Med Cell Longev ; 2022: 2615178, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105482

RESUMO

Amphibian skin is acknowledged to contain an antioxidant system composed of various gene-encoded antioxidant peptides, which exert significant effects on host defense. Nevertheless, recognition of such peptides is in its infancy so far. Here, we reported the antioxidant properties and underlying mechanism of a new antioxidant peptide, brevinin-1FL, identified from Fejervarya limnocharis frog skin. The cDNA sequence encoding brevinin-1FL was successfully cloned from the total cDNA of F. limnocharis and showed to contain 222 bp. The deduced mature peptide sequence of brevinin-1FL was FWERCSRWLLN. Functional analysis revealed that brevinin-1FL could concentration-dependently scavenge ABTS+, DPPH, NO, and hydroxyl radicals and alleviate iron oxidation. Besides, brevinin-1FL was found to show neuroprotective activity by reducing contents of MDA and ROS plus mitochondrial membrane potential, increasing endogenous antioxidant enzyme activity, and suppressing H2O2-induced death, apoptosis, and cycle arrest in PC12 cells which were associated with its regulation of AKT/MAPK/NF-κB signal pathways. Moreover, brevinin-1FL relieved paw edema, decreased the levels of TNF-α, IL-1ß, IL-6, MPO, and malondialdehyde (MDA), and restored catalase (CAT) and superoxide dismutase (SOD) activity plus glutathione (GSH) contents in the mouse injected by carrageenan. Together, these findings indicate that brevinin-1FL as an antioxidant has potent therapeutic potential for the diseases induced by oxidative damage. Meanwhile, this study will help us further comprehend the biological functions of amphibian skin and the mechanism by which antioxidants protect cells from oxidative stress.


Assuntos
Proteínas de Anfíbios , Antioxidantes , Proteínas de Anfíbios/química , Proteínas de Anfíbios/farmacologia , Proteínas de Anfíbios/uso terapêutico , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Carragenina , DNA Complementar , Peróxido de Hidrogênio/metabolismo , Camundongos , Estresse Oxidativo , Ranidae , Ratos
4.
Zootaxa ; 5165(4): 486-500, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-36101314

RESUMO

The Black-spotted Pond Frog, Pelophylax nigromaculatus, is widely distributed across mainland China, Korean Peninsula, and Japan. The taxonomic relationships among P. n. nigromaculatus, Rana nigromaculata mongolia (sensu P. n. mongolicus), and P. tenggerensis have long been ambiguous. Here we examine the topotype specimens of P. tenggerensis and R. n. mongolia, and provide phylogenic analyses based on four mitochondrial DNA sequences. The combined evidences from morphology and molecular phylogeny have shown the distinct specific-level of P. n. mongolicus that distant from P. nigromaculatus, while indicating the homogeneity between P. n. mongolicus and P. tenggerensis. Thus, we suggest elevating P. n. mongolicus as a full species Pelophylax mongolicus comb. nov., and place P. tenggerensis to be a secondary synonym of P. mongolicus comb. nov.


Assuntos
DNA Mitocondrial , Ranidae , Animais , DNA Mitocondrial/genética , Mitocôndrias/genética , Mongólia , Filogenia , Ranidae/genética
5.
Front Biosci (Landmark Ed) ; 27(8): 233, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-36042170

RESUMO

BACKGROUND: Hybrid taxa exist in nature, but their fitness can vary greatly. Hybrids are usually thought to have lower viability and survival rate than parental species due to the occurrence of two different genomes and divergent evolution in each species. On the other hand, the hybrid vigour of the F1 generation may give hybrids an advantage in mixed populations where they have to live and compete with parental taxa. Post-zygotic selection with endogenous genetic mechanisms may be a significant evolutionary force in hybrid formation. Here we tested principles of post-zygotic reproductive dynamics in mixed populations of Pelophylax water frogs that would help us understand the origin and maintenance of such systems. METHODS: Within experimental crosses, we combined various diploid Pelophylax genotypes resulting in 211 families. Statistical analysis of progeny was used to measure fertilization success, the rate of embryonic/tadpole mortality and the overall survival of the progeny till the time of metamorphosis. Using Generalized Estimating Equations models and variables defined by a mother/father included in mate pairs, we tested which factor best explains the successful embryonal development. RESULTS: The development of Pelophylax offspring significantly varied in survival rate and morphological malformations. These post-zygotic reproductive dynamics were driven by parental combinations of species pairs. The best values in the proportion of developing eggs, embryos, tadpoles and overall survival showed progeny of homospecific P. lessonae crosses. Total survival rates were relatively similar between L-E and R-E population systems but much lower than homospecific crosses in parental taxa. However, once the early stages passed this period, tadpoles mostly of hybrid hemiclonal origin performed even better than pure P. ridibundus progeny. Hybrid × hybrid crosses showed the highest mortality values. Statistical testing revealed that high mortality affected paternal genetic input. CONCLUSIONS: Combined three water frog taxa and both sexes provided patterns of post-zygotic reproduction dynamics of early development in the widespread population systems in Central Europe. The results further showed high survival rates of hybrid F1s created de novo from parental species despite significant divergence between P. ridibundus and P. lessonae DNA. Potential conservation measures of sexual-asexual systems in natural populations are discussed.


Assuntos
Hibridização Genética , Água , Animais , Pai , Feminino , Genômica , Humanos , Masculino , Ranidae/genética
6.
Oecologia ; 199(4): 1021-1033, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35984505

RESUMO

On a changing planet, amphibians must respond to weather events shifting in frequency and magnitude, and to how those temperature and precipitation changes interact with other anthropogenic disturbances that modify amphibian habitat. To understand how drastic changes in environmental conditions affect wood frog tadpoles, we tested five temperature manipulations, including Ambient (water temperatures tracking daily air temperatures), Elevated (+ 3 °C above ambient), Nightly (removal of nightly lows), Spike (+ 6 °C above ambient every third week), and Flux (alternating ambient and + 3 °C weekly) crossed with Low Salt (specific conductivity: 109-207 µS-cm) and High Salt (1900-2000 µS-cm). We replicated each of the ten resulting treatments four times. High-salinity conditions produced larger metamorphs than low-salinity conditions. Tadpole survival was reduced only by the Spike treatment (P = 0.017). Elevated temperatures did not shorten larval periods; time to metamorphosis did not differ among temperature treatments (P = 0.328). We retained 135 recently metamorphosed frogs in outdoor terrestrial enclosures for 10 months to investigate larval environment carryover effects. Juvenile frogs grew larger in low-density terrestrial enclosures than high density (P = 0.015) and frogs from Ambient Low Salt larval conditions grew and survived better than frogs from manipulated larval conditions. Frogs from High Salt larval conditions had lower survival than frogs from Low Salt conditions. Our results suggest that anthropogenic disturbances to larval environmental conditions can affect both larval and post-metamorphic individuals, with detrimental carryover effects of high-salinity larval conditions not emerging until the juvenile life stage.


Assuntos
Salinidade , Áreas Alagadas , Animais , Humanos , Larva , Metamorfose Biológica , Ranidae , Cloreto de Sódio , Temperatura
7.
Environ Pollut ; 311: 120009, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35998770

RESUMO

A pre-diabetes syndrome induced by endocrine disruptors (ED) was recently demonstrated in the model amphibian Silurana (Xenopus) tropicalis and was suggested to be a potential cause of amphibian population decline. However, such effects have not been found in wild type frogs exposed to ED and the capacity of amphibians to physiologically develop diabetes under natural conditions has not been confirmed. This study showed that a high fat diet (HFD) model displaying the important characteristics of mammal HFD models including glucose intolerance, insulin resistance and nonalcoholic fatty liver disease (NAFLD) can be developed with green frogs (Pelophylax spp.). Wild green frogs exposed to 10 µg L-1 benzo [a]pyrene (BaP) for 18 h also displayed several characteristics of the pre-diabetes phenotype previously observed in Xenopus including glucose intolerance, gluconeogenesis activation and insulin resistance. The study results confirmed that metabolic disorders induced by ED in wild green frogs are typical of the pre-diabetes phenotype and could serve as a starting point for field studies to determine the role of ED in the decline of amphibian populations. From an environmental perspective, the response of wild green frogs to different ED (10 µg L-1) suggests that a simple glucose-tolerance test could be used on wild anurans to identify bodies of water polluted with metabolic disruptors that could affect species fitness.


Assuntos
Disruptores Endócrinos , Intolerância à Glucose , Resistência à Insulina , Síndrome Metabólica , Estado Pré-Diabético , Rana clamitans , Animais , Benzo(a)pireno , Dieta Hiperlipídica/efeitos adversos , Disruptores Endócrinos/toxicidade , Mamíferos , Síndrome Metabólica/induzido quimicamente , Ranidae
8.
J Environ Manage ; 321: 116029, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36007384

RESUMO

Frogs are on the verge of extinction due to various biotic and abiotic stressors. Rivers, lakes, ponds, wetlands, and ditches that make up their habitats are exposed to different anthropogenic pollutants. Today, plastics stand out among these pollutants due to their widespread use; however, the information on microplastic (MP) accumulation in frogs is insufficient. In the present study, adult frog samples were collected from 19 different stations in Türkiye, including marsh frogs (Pelophylax ridibundus) from 18 stations and levantine frogs (Pelophylax bedriagae) from 1 station. MP was found in 147 (82.4%) of the 176 frogs that were analyzed. MP abundance in frogs varied between 0.20 and 18.93 MP individual-1. The characterization of MPs was determined predominantly as follows; PET (70.1%) in polymer type, fiber (92.2%) in shape, navy blue/blue (76.1%) in color, and >90% were smaller than 300 µm. No significant relationship with frog's weight (correlation coefficient = 0.01, P = 0.812) or length (correlation coefficient = 0.06, P = 0.473) and MP abundance was detected. The outcomes of this survey might be a baseline to assess the ecological risks posed by MPs and to guide future experimental research.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Animais , Anuros , Monitoramento Ambiental , Microplásticos , Plásticos , Prevalência , Ranidae , Água , Poluentes Químicos da Água/análise
9.
Environ Pollut ; 312: 120029, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36030957

RESUMO

Pollution caused by per- and polyfluoroalkyl substances (PFASs) has become a major global concern. The association between PFAS-induced hepatotoxicity and gut microbiota in amphibians, particularly at environmentally relevant concentrations, remains elusive. Herein we exposed male black-spotted frogs (Rana nigromaculata) to 1 and 10 µg/L waterborne perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) for 21 days; subsequently, liver histopathological, oxidative stress, molecular docking, gene/protein expression, and gut microbiome analyses were conducted. PFOS and 6:2 Cl-PFESA exposure enhanced serum alanine aminotransferase and aspartate aminotransferase activities, and markedly increased hepatic area of vacuoles and inflammatory cell infiltration, while PFOA exposure increased serum alanine aminotransferase but not aspartate aminotransferase activities and affected hepatic area of vacuoles and inflammatory cell infiltration to a lesser extent. All three PFASs elevated catalase, glutathione S-transferase, and glutathione peroxidase activities and glutathione and malondialdehyde contents in the liver, suggesting the induction of oxidative stress. Further, PFASs could bind to mitogen-activated protein kinases (p38, ERK, and JNK), upregulating not only their expression but also the expression of downstream oxidative stress-related genes and that of P-p38, P-ERK, and Nrf2 proteins. In addition, PFAS exposure significantly increased the relative abundance of Proteobacteria and Delftia and decreased that of Firmicutes and Dietzia, Mycoplasma, and Methylobacterium-Methylorubrum in the order of PFOS ≈ 6:2 Cl-PFESA > PFOA. Altogether, it appears that PFOS and 6:2 Cl-PFESA are more toxic than PFOA. Finally, microbiota function prediction, microbiota co-occurrence network, and correlation analysis between gut microbiota and liver indices suggested that PFAS-induced hepatotoxicity was associated with gut microbiota dysbiosis. Our data provide new insights into the role of gut microbiota in PFAS-induced hepatotoxicity in frogs.


Assuntos
Ácidos Alcanossulfônicos , Doença Hepática Induzida por Substâncias e Drogas , Fluorcarbonetos , Microbioma Gastrointestinal , Alanina Transaminase , Ácidos Alcanossulfônicos/toxicidade , Animais , Caprilatos , Catalase , Éteres , Fluorcarbonetos/análise , Fluorcarbonetos/toxicidade , Glutationa , Glutationa Peroxidase , Glutationa Transferase , Masculino , Malondialdeído , Proteínas Quinases Ativadas por Mitógeno , Simulação de Acoplamento Molecular , Fator 2 Relacionado a NF-E2 , Ranidae
10.
Chemosphere ; 307(Pt 4): 136202, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36037957

RESUMO

Among others, the global change involves a worldwide increase in cropland area, with the concomitant rise in nitrogenous fertilizer supplementation and species range alterations, including parasites and pathogens. As most animals rely on their immune systems against these infectious agents, studying the potential effects of nitrogenous compounds on animal immune response is vital to understand their susceptibility to infections under these altered circumstances. Being subjected to an alarming process of global declines, amphibians are the object of particular attention, given their sensitivity to these compounds, especially to ammonium. Moreover, whereas adults can actively avoid polluted patches, larvae are confined within their waterbodies, thus exposed to contaminants in it. In this work, we test whether chronic exposure to a sublethal dose of ammonium during the larval stage of Pelophylax perezi frogs, released from all contamination after metamorphosis, leads to impaired inflammatory response to phytohemagglutinin in adults. We also test whether such a response differs between agrosystem individuals as compared with conspecifics from natural habitats. We found negative carryover effects of chronic exposure of larvae to ammonium on adult inflammatory response, which could imply a greater susceptibility to pathogens and parasites. However, this damage is only true for males, which, according to the immunocompetence handicap hypothesis, could be a consequence of a testosterone-triggered impairment of male immune function. In disagreement with our prediction, however, we detected no differences in the inflammatory response of agrosystem frogs to phytohemagglutinin as compared with natural habitat conspecifics.


Assuntos
Compostos de Amônio , Poluentes Químicos da Água , Compostos de Amônio/toxicidade , Animais , Anuros , Fertilizantes , Larva , Masculino , Fito-Hemaglutininas/farmacologia , Ranidae/fisiologia , Testosterona/farmacologia , Poluentes Químicos da Água/análise
11.
Dev Comp Immunol ; 137: 104519, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36041640

RESUMO

Brevinins exhibit a wide range of structural features and strong biological activities. Brevinin-2, derived from several amphibians, has shown antimicrobial activities. However, little is known about the wound-healing activity of brevinin-2. In this study, brevinin-2 cDNA was identified from the skin transcriptome of the dark-spotted frog (Pelophylax nigromaculatus) and it comprises a signal peptide, a propeptide, and a mature peptide. Sequence alignment with brevinin-2 derived from other amphibians showed variability of the mature peptide, and the presence of a C-terminal cyclic heptapeptide domain (Cys-Lys-Xaa4-Cys) in the mature peptide. Dark-spotted frog brevinin-2 belonged to the brevinin-2 cluster and was closely related to brevinin-2HB1 from Pelophylax hubeiensis. Synthetic dark-spotted frog brevinin-2 mature peptide (brevinin-2PN) exhibited antibacterial activity against several pathogens by destroying cell membrane integrity and hydrolysis of genomic DNA. Brevinin-2PN exhibited significant wound-healing activity by accelerating the healing of human skin fibroblast cell scratches, influencing cell migration, and stimulating gene expression of growth factors.


Assuntos
Proteínas de Anfíbios , Peptídeos Antimicrobianos , Sequência de Aminoácidos , Proteínas de Anfíbios/genética , Proteínas de Anfíbios/metabolismo , Animais , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/metabolismo , Anuros/genética , DNA Complementar/metabolismo , Humanos , Sinais Direcionadores de Proteínas , Ranidae/genética , Pele/metabolismo
12.
Environ Sci Technol ; 56(18): 13222-13232, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36044002

RESUMO

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous environmental pollutants, causing environmental threats and public health concerns, but information regarding PFAS hepatotoxicity remains elusive. We investigated the effects of PFASs on lipid metabolism in black-spotted frogs through a combined field and laboratory study. In a fluorochemical industrial area, PFASs seriously accumulate in frog tissues. PFAS levels in frog liver tissues are positively related to the hepatosomatic index along with triglyceride (TG) and cholesterol (TC) contents. In the laboratory, frogs were exposed to 1 and 10 µg/L PFASs, respectively (including PFOA, PFOS, and 6:2 Cl-PFESA). At 10 µg/L, PFASs change the hepatic fatty acid composition and significantly increase the hepatic TG content by 1.33 to 1.87 times. PFASs induce cross-talk accumulation of TG, TC, and their metabolites between the liver and serum. PFASs can bind to LXRα and PPARα proteins, further upregulate downstream lipogenesis-related gene expression, and downregulate lipolysis-related gene expression. Furthermore, lipid accumulation induced by PFASs is alleviated by PPARα and LXRα antagonists, suggesting the vital role of PPARα and LXRα in PFAS-induced lipid metabolism disorders. This work first reveals the disruption of PFASs on hepatic lipid homeostasis and provides novel insights into the occurrence and environmental risk of PFASs in amphibians.


Assuntos
Ácidos Alcanossulfônicos , Poluentes Ambientais , Fluorcarbonetos , Ácidos Alcanossulfônicos/toxicidade , Animais , Anuros/metabolismo , China , Poluentes Ambientais/metabolismo , Ácidos Graxos , Fluorcarbonetos/análise , Fluorcarbonetos/toxicidade , Metabolismo dos Lipídeos , PPAR alfa/metabolismo , Ranidae/metabolismo , Triglicerídeos
13.
Toxicol In Vitro ; 83: 105427, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35777580

RESUMO

Chemicals used in our daily life show different toxic effects to the aquatic and terrestrial species and thus hamper the ecological balance. In the present time, amphibians are one of them, which are threatened to be extinct. Quantitative structure-activity relationship (QSAR) is an useful tool for prediction involving less time, money and manpower without requiring any animal experiments to assess the unavailable acute toxicity data for the untested molecules. In this study, we have developed QSAR models for ecotoxicity of some waterborne diverse aromatic compounds on an amphibian species Rana japonica (Japanese brown frog) employing Genetic Algorithm (GA) for variable selection followed by Partial Least Squares (PLS) regression method following recommendations of the Organization for Economic Co-operation and Development (OECD) for QSAR model development. Double cross-validation (DCV) followed by Best Subset Selection (BSS) were employed to select suitable models. The models displayed promising statistical quality in terms of R2 (= 0.837-0.841), Q2LOO (= 0.782-0.787), R2pred or Q2F1 (= 0.802-0.82) and some other internal and external validation metrics for tadpoles of Rana japonica (NTraining = 44, NTest = 14). These models can be applied for data gap filling for a new untested compound falling within the applicability domain (AD) of the models.


Assuntos
Quimiometria , Compostos Orgânicos , Animais , Análise dos Mínimos Quadrados , Relação Quantitativa Estrutura-Atividade , Ranidae
14.
Food Chem ; 396: 133632, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-35820285

RESUMO

This work was dedicated to evaluating the drying methods (freeze drying, spray drying, and vacuum drying) of food Rana chensinensis ovum protein isolate (RCOPI) based on comparison of the physicochemical and functional properties. The characterization and evaluation were conducted using scanning electron microscopy, surface hydrophobicity, SDS-PAGE, amino acid composition and nutritional parameters, Fourier transform infrared spectroscopy, and autofluorescence spectroscopy. The results showed the protein structure and conformation of RCOPI were greatly affected by drying techniques, leading to different physicochemical and functional properties. RCOPI possessed four main subunit bands distributed around 110, 90, 35 and 32 kDa. Seven essential amino acids were detected, accounting for 43.27-43.65% of total amino acids. Freeze drying RCOPI (FD-RCOPI) showed superior functional features, including solubility, water holding capacity, oil holding capacity, stabilization of Pickering emulsion and antioxidant capacity. FD-RCOPI exhibited applicability for the manufacture of viscous foods, bakery products and Pickering emulsions.


Assuntos
Aminoácidos , Dessecação , Animais , Dessecação/métodos , Composição de Medicamentos , Emulsões , Liofilização , Ranidae , Solubilidade
15.
Cell Signal ; 98: 110408, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35842171

RESUMO

Freeze-tolerant species, such as wood frogs (Rana sylvatica), are susceptible to multiple co-occurring stresses that they must overcome to survive. Freezing is accompanied by mechanical stress and dehydration due to ice crystal formation in the extracellular space, ischemia/anoxia due to interruption in blood flood, and hyperglycemia due to cryoprotective measures. Wood frogs can survive dehydration, anoxia, and high glucose stress independently of freezing, thereby creating a multifactorial model for studying freeze-tolerance. Oxidative stress and high glucose levels favors the production of pro-oxidant molecules and advanced glycation end product (AGE) adducts that could cause substantial cellular damage. In this study, the involvement of the high mobility group box 1 (HMGB1)-AGE/RAGE (receptor for AGE) axis and the regulation of ETS1 and EGR1-mediated angiogenic responses were investigated in liver of wood frogs expose to freeze/thaw, anoxia/reoxygenation and dehydration/rehydration treatments. HMGB1 and not AGE-adducts are likely to induce the activation of ETS1 and EGR1 via the RAGE pathway. The increase in nuclear localization of both ETS1 and EGR1, but not DNA binding activity in response to stress hints to a potential spatial and temporal regulation in inducing angiogenic factors. Freeze/thaw and dehydration/rehydration treatments increase the levels of both pro- and anti-angiogenic factors, perhaps to prepare for the distribution of cryoprotectants or enable the repair of damaged capillaries and wounds when needed. Overall, wood frogs appear to anticipate the need for angiogenesis in response to freezing and dehydration but not anoxic treatments, probably due to mechanical stress associated with the two former conditions.


Assuntos
Proteína HMGB1 , Indutores da Angiogênese/metabolismo , Animais , Desidratação/metabolismo , Redes Reguladoras de Genes , Glucose/metabolismo , Produtos Finais de Glicação Avançada/genética , Proteína HMGB1/metabolismo , Hipóxia/metabolismo , Ranidae/genética , Ranidae/metabolismo
16.
Dev Growth Differ ; 64(6): 279-289, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35881001

RESUMO

Sex chromosomes in poikilothermal vertebrates are characterized by rapid and diverse evolution at the species or population level. Our previous study revealed that the Taiwanese frog Odorrana swinhoana (2n = 26) has a unique system of multiple sex chromosomes created by three sequential translocations among chromosomes 1, 3, and 7. To reveal the evolutionary history of sex chromosomes in the Odorrana species complex, we first identified the original, homomorphic sex chromosomes, prior to the occurrence of translocations, in the ancestral-type population of O. swinhoana. Then, we extended the investigation to a closely related Japanese species, Odorrana utsunomiyaorum, which is distributed on two small islands. We used a high-throughput nuclear genomic approach to analyze single-nucleotide polymorphisms and identify the sex-linked markers. Those isolated from the O. swinhoana ancestral-type population were found to be aligned to chromosome 1 and showed male heterogamety. In contrast, almost all the sex-linked markers isolated from O. utsunomiyaorum were heterozygous in females and homozygous in males and were aligned to chromosome 9. Morphologically, we confirmed chromosome 9 to be heteromorphic in females, showing a ZZ-ZW sex determination system, in which the W chromosomes were heterochromatinized in a stripe pattern along the chromosome axis. These results indicated that after divergence of the two species, the ancestral homomorphic sex chromosome 1 underwent highly rapid and diverse evolution, i.e., sequential translocations with two autosomes in O. swinhoana, and turnover to chromosome 9 in O. utsunomiyaorum, with a transition from XY to ZW heterogamety and change to heteromorphy.


Assuntos
Cromossomos Sexuais , Processos de Determinação Sexual , Animais , Anuros/genética , Evolução Molecular , Feminino , Genoma , Masculino , Ranidae/genética , Cromossomos Sexuais/genética , Processos de Determinação Sexual/genética
17.
Mol Phylogenet Evol ; 175: 107575, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35835426

RESUMO

The New Zealand wattlebirds (Callaeidae) are an endemic New Zealand passerine family whose species show extreme variation in bill morphology. In particular, the extinct huia (Heteralocha acutirostris) has attracted considerable attention because it exhibited extreme sexual dimorphism in bill morphology. However, the phylogenetic relationships within the Callaeidae, crucial for understanding bill evolution in the family, have not been resolved to date. Here we present phylogenies based on complete mitochondrial genome sequences and nuclear ultraconserved elements. Kokako (Callaeas spp.) is strongly supported as sister taxon to saddleback/tieke (Philesturnus spp.) and huia, diverging around 6.8 Ma. Saddleback and huia are estimated to have split from each other 5 Ma, indicating that the extreme sexual bill dimorphism in huia has evolved within this time frame. Our estimates for the divergences within the Callaetidae are similar to, or younger than, those of most other endemic New Zealand avian families, therefore the observed bill variation is not a consequence of a longer divergence time. Instead, the expansion of the huia into the wood-foraging niche, combined with the sexual dimorphism it evolved in order to optimise feeding on this resource, has been the main contributor to the large variation of bill morphologies within this family.


Assuntos
Genoma Mitocondrial , Passeriformes , Animais , Humanos , Passeriformes/genética , Filogenia , Ranidae , Caracteres Sexuais
18.
J Comp Physiol B ; 192(5): 669-682, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35857071

RESUMO

Environmental stress is a major driver of ecological and evolutionary processes in nature. To cope with stress, organisms can adjust through phenotypic plasticity and/or adapt through genetic change. Here, we compared short-term behavioural (activity) and physiological (corticosterone levels, CORT) responses of Rana arvalis tadpoles from two divergent populations (acid origin, AOP, versus neutral origin, NOP) to acid and predator stress. Tadpoles were initially reared in benign conditions at pH 7 and then exposed to a combination of two pH (acid versus neutral) and two predator cue (predator cue versus no predator cue) treatments. We assessed behavioural activity within the first 15 min, and tissue CORT within 8 and 24 h of stress exposure. Both AOP and NOP tadpoles reduced their activity in acidic pH, but the response to the predator cue differed between the populations: AOP tadpoles increased whereas NOP tadpoles decreased their activity. The AOP and NOP tadpoles differed also in their CORT responses, with AOP being more responsive (CORT levels of NOP tadpoles did not differ statistically across treatments). After 8 h exposure, AOP tadpoles had elevated CORT levels in the acid-predator cue treatment and after 24 h exposure they had elevated CORT levels in all three stress treatments (relative to the benign neutral-no-cue treatment). These results suggest that adaptation to environmental acidification in R. arvalis is mediated, in part, via behavioural and hormonal plasticity.


Assuntos
Comportamento Predatório , Ranidae , Animais , Corticosterona , Concentração de Íons de Hidrogênio , Larva/fisiologia , Comportamento Predatório/fisiologia , Ranidae/fisiologia
19.
World J Microbiol Biotechnol ; 38(9): 162, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35834028

RESUMO

Brevinin2-CE (B2CE), a natural peptide containing 37 amino acids, was first isolated from the skin secretions of the Chinese forest frog Rana chensinensis. B2CE shows good antibacterial activity. In this study, a series of B2CE analogs with differences in cationicity, α-helicity, hydrophobicity and amphipathic properties were designed through chain-length deletion and amino acid substitution. The most potent, nontoxic analog, B2CE-N26V5K, was identified by examination of its antibacterial activity, hemolytic activity, and stability under physiological conditions. The increased cationicity, hydrophobicity and more obvious hydrophilic and hydrophobic surface of B2CE-N26-N16WA18KG23K did not improve the antibacterial activity but increased the hemolytic activity of this modified peptide. The helicity might promote antibacterial activity for brevinin-2 peptides, as the 15-aa analogs with lower helicity show decreased potency against different test bacteria (approximately 2- to 72-fold) compared to B2CE-N26V5K. Additionally, the results indicated that the "Rana box" does not affect the antimicrobial activity of brevinin-2 peptides, as B2CE, B2CE-nonDS and B2CE-C31-37 S have similar strong inhibitory effects on both gram-positive and gram-negative bacteria. However, the "Rana box" does affect the hemolytic activity, as the HC50 values of the 3 peptides range from 25 ~ 130 µM. Furthermore, B2CE-N26V5K caused obvious morphological alterations of the bacterial surfaces, as shown by atomic force microscopy. Additionally, B2CE-N26V5K exhibited strong membrane-disrupting activity when examined using the LIVE/DEAD Bac Light Bacterial Viability Kit. Thus, the antibacterial effect of B2CE-N26V5K on gram-negative and gram-positive bacteria may be caused by cell membrane attack. In conclusion, the excellent candidate B2CE-N26V5K was obtained and has application prospects as a novel anti-infective agent.


Assuntos
Anti-Infecciosos , Peptídeos Catiônicos Antimicrobianos , Animais , Antibacterianos/química , Anti-Infecciosos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Bactérias/metabolismo , Bactérias Gram-Negativas , Bactérias Gram-Positivas/metabolismo , Hemólise , Testes de Sensibilidade Microbiana , Ranidae/metabolismo
20.
Amino Acids ; 54(9): 1327-1336, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35852614

RESUMO

Naturally occurring frog skin peptides are one of largest sources of antimicrobial peptides that have many advantages including high potency, broad spectrum of targets and low susceptibility to multiple drug-resistance bacteria. However, they also have disadvantages such as hemolytic activity, low stability and high production costs. For these reasons, various strategies have been applied to overcome these drawbacks restricting their use in clinical trials. Previously reported brevinin-1GHa (BR-1GHa) is a 24 amino acid long antimicrobial peptide isolated from Hylarana guentheri with hemolytic activity. To enhance the antimicrobial activity of this peptide and to reduce its hemolytic activity, we designed five new temporin like analogues and examined their bioactivities. Temporins are another class of frog skin peptides without hemolytic activity and shorter than brevinins. When the antimicrobial activities of new analogues were examined against a panel of microorganisms, BR-1GHa-3, in which two alanine residues in the truncated version of BR-1GHa were replaced with leucine, exhibited significantly improved antimicrobial activity against Gram-positive bacterial strains (e.g., S. aureus ATCC 29213 and E. casseliflavus ATCC 700327) with lower hemolytic activity compared to the BR-1GHa peptide. Furthermore, BR-1GHa-4 analogue, in which Gly3 was replaced with Pro, did not show any hemolytic activity except for highest (128 µM) concentration tested and have a strong antimicrobial effect on Gram-positive bacteria (e.g., E. faecalis ATCC 51299 and B. cereus ATCC 13061).


Assuntos
Anti-Infecciosos , Staphylococcus aureus , Sequência de Aminoácidos , Proteínas de Anfíbios/química , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/química , Bactérias Gram-Positivas , Hemólise , Testes de Sensibilidade Microbiana , Ranidae , Pele/metabolismo
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