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1.
Sci Rep ; 14(1): 18769, 2024 08 13.
Artículo en Inglés | MEDLINE | ID: mdl-39138237

RESUMEN

Infections by drug-resistant microorganisms are a threat to global health and antimicrobial peptides are considered to be a new hope for their treatment. Temporin-WY2 was identified from the cutaneous secretion of the Ranidae frog, Amolops wuyiensis. It presented with a potent anti-Gram-positive bacterial efficacy, but its activity against Gram-negative bacteria and cancer cell lines was unremarkable. Also, it produced a relatively high lytic effect on horse erythrocytes. For further improvement of its functions, a perfect amphipathic analogue, QUB-1426, and two lysine-clustered analogues, 6K-WY2 and 6K-1426, were synthesised and investigated. The modified peptides were found to be between 8- and 64-fold more potent against Gram-negative bacteria than the original peptide. Additionally, the 6K analogues showed a rapid killing rate. Also, their antiproliferation activities were more than 100-fold more potent than the parent peptide. All of the peptides that were examined demonstrated considerable biofilm inhibition activity. Moreover, QUB-1426, 6K-WY2 and 6K-1426, demonstrated in vivo antimicrobial activity against MRSA and E. coli in an insect larvae model. Despite observing a slight increase in the hemolytic activity and cytotoxicity of the modified peptides, they still demonstrated a improved therapeutic index. Overall, QUB-1426, 6K-WY2 and 6K-1426, with dual antimicrobial and anticancer functions, are proposed as putative drug candidates for the future.


Asunto(s)
Péptidos Catiónicos Antimicrobianos , Biopelículas , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana , Animales , Péptidos Catiónicos Antimicrobianos/farmacología , Péptidos Catiónicos Antimicrobianos/química , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Biopelículas/efectos de los fármacos , Humanos , Antibacterianos/farmacología , Antibacterianos/química , Ranidae , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Caballos , Escherichia coli/efectos de los fármacos , Hemólisis/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Proteínas Anfibias/farmacología , Proteínas Anfibias/química , Bacterias Gramnegativas/efectos de los fármacos
2.
J Parasitol ; 110(4): 339-350, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39099080

RESUMEN

Two new species of lung-dwelling nematodes are described from North American frogs: Rhabdias aurorae n. sp. from Rana aurora and Rhabdias conni n. sp. from Rana clamitans and Rana catesbeiana from Arkansas; the latter species was also found in Oklahoma and Georgia. Rhabdias aurorae n. sp. differs from other Nearctic congeners in the combination of the following characteristics: buccal capsule 22-25 µm wide, elongated tail covered with inflated cuticle, esophagus with prominent dilatation in anterior part and 6 small circumoral lips. Rhabdias conni n. sp. is morphologically closest to Rhabdias ranae Walton, 1929 and Rhabdias joaquinensisIngles, 1936; it differs from them in the shape of lateral pseudolabia, the dimensions of the body, and the egg size. Both new species were found to be significantly different from the Nearctic congeners in the nucleotide sequences of nuclear ribosomal DNA (18S-ITS-28S region), 12S, and CO1 mitochondrial genes. The 2 new species differ from other currently sequenced Nearctic congeners by 1.1-2.7% of nucleotide positions in the nuclear rDNA region, 1.3-3.4% in the 12S gene, and 3.4-9.4% in CO1 gene. Molecular phylogenetic analysis based on nuclear ribosomal DNA sequences placed both new species into the clade consisting of Nearctic and Neotropical Rhabdias spp. The position of Rh. aurorae n. sp. within the clade is uncertain because of a polytomy, but Rh. conni n. sp. is nested within the "Rh. joaquinensis complex" related to Rh. ranae and Rhabdias tarichaeKuzmin, Tkach, and Snyder, 2003. The phylogenetic analysis based on nuclear ribosomal DNA sequences has revealed 3 evolutionary host-switching events from anuran to caudatan hosts among Rhabdias spp. that occurred in the Nearctic and Palearctic. The molecular phylogeny also suggests that Rhabdias may have originally evolved in what is now Africa.


Asunto(s)
ADN Ribosómico , Filogenia , Ranidae , Infecciones por Rhabditida , Animales , Ranidae/parasitología , Masculino , Femenino , Infecciones por Rhabditida/parasitología , Infecciones por Rhabditida/veterinaria , ADN Ribosómico/química , Georgia , Oklahoma , Arkansas , ARN Ribosómico 28S/genética , Pulmón/parasitología , ADN de Helmintos/química , ARN Ribosómico 18S/genética , Rhabditoidea/clasificación , Rhabditoidea/genética , Rhabditoidea/anatomía & histología , Microscopía Electrónica de Rastreo/veterinaria
3.
Sci Rep ; 14(1): 15388, 2024 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-38965296

RESUMEN

Ectothermic animals that live in seasonally cold regions must adapt to seasonal variation and specific environmental conditions. During the winter, some amphibians hibernate on land and encounter limited environmental water, deficient oxygen, and extremely low temperatures that can cause the whole body freezing. These stresses trigger physiological and biochemical adaptations in amphibians that allow them to survive. Rana sylvatica, commonly known as the wood frog, shows excellent freeze tolerance. They can slow their metabolic activity to a near halt and endure freezing of 65-70% of their total body water as extracellular ice during hibernation, returning to normal when the temperatures rise again. To investigate the molecular adaptations of freeze-tolerant wood frogs, a comprehensive proteomic analysis was performed on frog liver tissue after anoxia, dehydration, or freezing exposures using a label-free LC-MS/MS proteomic approach. Quantitative proteomic analysis revealed that 87, 118, and 86 proteins were significantly upregulated in dehydrated, anoxic, and frozen groups, suggesting potential protective functions. The presence of three upregulated enzymes, glutathione S-transferase (GST), aldolase (ALDOA), and sorbitol dehydrogenase (SORD), was also validated. For all enzymes, the specific enzymatic activity was significantly higher in the livers of frozen and anoxic groups than in the controls. This study reveals that GST, ALDOA, and SORD might participate in the freeze tolerance mechanism by contributing to regulating cellular detoxification and energy metabolism.


Asunto(s)
Deshidratación , Congelación , Hipoxia , Hígado , Proteómica , Ranidae , Animales , Hígado/metabolismo , Proteómica/métodos , Ranidae/metabolismo , Deshidratación/metabolismo , Hipoxia/metabolismo , Proteoma/metabolismo , Espectrometría de Masas en Tándem , Respuesta al Choque por Frío
4.
Anal Chem ; 96(29): 12057-12064, 2024 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-38979842

RESUMEN

De novo sequencing of any novel peptide/protein is a difficult task. Full sequence coverage, isomeric amino acid residues, inter- and intramolecular S-S bonds, and numerous other post-translational modifications make the investigators employ various chemical modifications, providing a variety of specific fragmentation MSn patterns. The chemical processes are time-consuming, and their yields never reach 100%, while the subsequent purification often leads to the loss of minor components of the initial peptide mixture. Here, we present the advantages of the EThcD method that enables establishing the full sequence of natural intact peptides of ranid frogs in de novo top-down mode without any chemical modifications. The method provides complete sequence coverage, including the cyclic disulfide section, and reliable identification of isomeric leucine/isoleucine residues. The proposed approach demonstrated its efficiency in the analysis of peptidomes of ranid frogs from several populations of Rana arvalis, Rana temporaria, and Pelophylax esculentus complexes.


Asunto(s)
Péptidos , Ranidae , Animales , Péptidos/química , Péptidos/análisis , Péptidos/metabolismo , Secuencia de Aminoácidos , Análisis de Secuencia de Proteína/métodos , Proteínas Anfibias/química , Proteínas Anfibias/metabolismo
5.
Artículo en Inglés | MEDLINE | ID: mdl-38969165

RESUMEN

Wood frogs are freeze-tolerant vertebrates that can endure weeks to months frozen during the winter without breathing and with as much as 65% of total body water frozen as extracellular ice. Underlying tolerances of anoxia and of cellular dehydration support whole body freezing. One pro-survival mechanism employed by these frogs is epigenetic modifications via DNA hypomethylation processes facilitating transcriptional repression or activation. These processes involve proteins such as DNA Methyltransferases (DNMTs), Methyl Binding Domain proteins (MBDs), Ten-Eleven Translocases (TETs), and Thymine Deglycosylase (TDG). The present study evaluates the responses of these proteins to dehydration and anoxia stresses in wood frog liver. DNMT relative protein expression was reduced in liver, but nuclear DNMT activity did not change significantly under anoxia stress. By contrast, liver DNMTs and nuclear DNMT activity were upregulated under dehydration stress. These stress-specific differences were speculated to arise from Post-Translational Modifications (PTMs). DNMT3A and DNMT3B showed increased relative protein expression during recovery from dehydration and anoxia. Further, MBD1 was elevated during both conditions suggesting transcriptional repression. TET proteins showed varying responses to anoxia likely due to the absence of oxygen, a main substrate required by TETs. Similarly, TDG, an enzyme that corrects DNA damage, was downregulated under anoxia potentially due to lower levels of reactive oxygen species that damage DNA, but levels returned to normal during reperfusion of oxygen. Our results indicate differential stress-specific responses that indicate the need for more research in the DNA hypomethylation mechanisms employed by the wood frog during stress.


Asunto(s)
Metilación de ADN , Deshidratación , Hipoxia , Hígado , Animales , Deshidratación/metabolismo , Hígado/metabolismo , Hipoxia/metabolismo , Hipoxia/genética , Ranidae/metabolismo , Ranidae/genética , Proteínas Anfibias/metabolismo , Proteínas Anfibias/genética , Estrés Fisiológico
6.
Biomolecules ; 14(7)2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-39062553

RESUMEN

Epigenetic regulation, notably histone post-translational modification (PTM), has emerged as a major transcriptional control of gene expression during cellular stress adaptation. In the present study, we use an acid extraction method to isolate total histone protein and investigate dynamic changes in 23 well-characterized histone methylations/acetylations in the brains of wood frogs subject to 24-h freezing and subsequent 8-h thawed recovery conditions. Our results identify four histone PTMs (H2BK5ac, H3K14ac, H3K4me3, H3K9me2) and three histone proteins (H1.0, H2B, H4) that were significantly (p < 0.05) responsive to freeze-thaw in freeze-tolerant R. sylvatica brains. Two other permissive modifications (H3R8me2a, H3K9ac) also trended downwards following freezing stress. Together, these data are strongly supportive of the proposed global transcriptional states of hypometabolic freeze tolerance and rebounded thawed recovery. Our findings shed light on the intricate interplay between epigenetic regulation, gene transcription and energy metabolism in wood frogs' adaptive response to freezing stress.


Asunto(s)
Encéfalo , Congelación , Histonas , Procesamiento Proteico-Postraduccional , Ranidae , Animales , Encéfalo/metabolismo , Histonas/metabolismo , Ranidae/metabolismo , Ranidae/genética , Epigénesis Genética , Metilación , Código de Histonas
7.
Parasitol Int ; 102: 102920, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38969332

RESUMEN

Water frogs of the genus Pelophylax host a variety of parasites, from protozoa to helminths. Among the blood parasites, representatives of Apicomplexa, Trypanosoma and Nematoda show the highest prevalence. In this study, we focused on blood parasites of water frogs living in the Danube Delta, Romania. In total, 74 individuals of P. ridibundus and eight individuals of P. esculentus from six localities were examined. Blood parasites were detected microscopically and using a molecular marker (18S rDNA). 89.77% of frogs from all investigated localities were found to be infected with at least one parasitic group, specifically with haemogregarines (84.09%), nematodes (1.14%), and trypanosomes (63.64%). The parasitemia of haemogregarines and trypanosomes differed significantly among the studied locations. There was no statistically significant difference in parasitemia between male and female hosts. However, adults were found to have a significantly higher parasitemia in comparison with subadults infected with haemogregarines. Correlation between parasitemia and the body length of frogs infected with haemogregarines was also significant (r = 0.226). By comparing the 18S rDNA sequences with the corresponding GenBank sequences, Hepatozoon species identified in water frogs showed a close similarity (98.1-99.8%) to Hepatozoon magna. Trypanosomes showed the highest sequence similarity to Trypanosoma sp. isolate R10 clone L2-3, Trypanosoma ranarum, and Trypanosoma cobitis.


Asunto(s)
Parasitemia , ARN Ribosómico 18S , Ranidae , Animales , Rumanía/epidemiología , Ranidae/parasitología , Masculino , Femenino , Parasitemia/veterinaria , Parasitemia/parasitología , Parasitemia/epidemiología , ARN Ribosómico 18S/análisis , Trypanosoma/aislamiento & purificación , Trypanosoma/clasificación , Trypanosoma/genética , Filogenia , Nematodos/aislamiento & purificación , Nematodos/clasificación
8.
Chemosphere ; 363: 142874, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39019178

RESUMEN

Zinc (Zn) contaminants in the aquatic environment have an intricate impact on amphibians. Amphibian gut and skin microbiota are participated in regulating their normal physiological functions. Here, we investigated the effects of Zn on the gut and skin tissues and microbiota of Bufo gargarizans and Rana chensinensis tadpoles using histological methods and 16S rRNA sequencing technology. Our results showed a decrease in the height of enterocytes and skin epithelial cells after Zn treatment. Furthermore, Zn exposure elicited alterations in the composition and structure of the gut and skin microbiota at the phylum and genus levels in Bufo gargarizans and Rana chensinensis tadpoles. The feature predictions revealed an elevation in the abundance of potentially pathogenic bacteria and stress-tolerant bacteria in the gut and skin of both tadpoles after zinc exposure. We also speculated that microbiota from various species and organs exhibit varying degrees of sensitivity to zinc based on the functional predictions results. In the context of increasing environmental pollution and the global amphibians decline, our research enriches the current understanding of effects of zinc on amphibian microbiota and provides new framework for artificial breeding and amphibian conservation.


Asunto(s)
Bufonidae , Larva , Ranidae , Piel , Zinc , Animales , Zinc/toxicidad , Larva/efectos de los fármacos , Ranidae/microbiología , Piel/efectos de los fármacos , Piel/microbiología , Bufonidae/microbiología , ARN Ribosómico 16S/genética , Contaminantes Químicos del Agua/toxicidad , Intestinos/microbiología , Intestinos/efectos de los fármacos , Microbioma Gastrointestinal/efectos de los fármacos , Bacterias/efectos de los fármacos , Bacterias/clasificación , Bacterias/genética , Microbiota/efectos de los fármacos
9.
Mol Ecol ; 33(14): e17438, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38923007

RESUMEN

A common goal in evolutionary biology is to discern the mechanisms that produce the astounding diversity of morphologies seen across the tree of life. Aposematic species, those with a conspicuous phenotype coupled with some form of defence, are excellent models to understand the link between vivid colour pattern variations, the natural selection shaping it, and the underlying genetic mechanisms underpinning this variation. Mimicry systems in which species share a conspicuous phenotype can provide an even better model for understanding the mechanisms of colour production in aposematic species, especially if comimics have divergent evolutionary histories. Here we investigate the genetic mechanisms by which mimicry is produced in poison frogs. We assembled a 6.02-Gbp genome with a contig N50 of 310 Kbp, a scaffold N50 of 390 Kbp and 85% of expected tetrapod genes. We leveraged this genome to conduct gene expression analyses throughout development of four colour morphs of Ranitomeya imitator and two colour morphs from both R. fantastica and R. variabilis which R. imitator mimics. We identified a large number of pigmentation and patterning genes differentially expressed throughout development, many of them related to melanophores/melanin, iridophore development and guanine synthesis. We also identify the pteridine synthesis pathway (including genes such as qdpr and xdh) as a key driver of the variation in colour between morphs of these species, and identify several plausible candidates for colouration in vertebrates (e.g. cd36, ep-cadherin and perlwapin). Finally, we hypothesise that keratin genes (e.g. krt8) are important for producing different structural colours within these frogs.


Asunto(s)
Mimetismo Biológico , Fenotipo , Pigmentación , Animales , Mimetismo Biológico/genética , Pigmentación/genética , Genómica , Ranidae/genética , Ranidae/crecimiento & desarrollo , Genoma/genética , Evolución Biológica , Selección Genética , Anuros/genética , Anuros/crecimiento & desarrollo
10.
Dev Biol ; 514: 66-77, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38851558

RESUMEN

The ways in which animals sense the world changes throughout development. For example, young of many species have limited visual capabilities, but still make social decisions, likely based on information gathered through other sensory modalities. Poison frog tadpoles display complex social behaviors that have been suggested to rely on vision despite a century of research indicating tadpoles have poorly-developed visual systems relative to adults. Alternatively, other sensory modalities, such as the lateral line system, are functional at hatching in frogs and may guide social decisions while other sensory systems mature. Here, we examined development of the mechanosensory lateral line and visual systems in tadpoles of the mimic poison frog (Ranitomeya imitator) that use vibrational begging displays to stimulate egg feeding from their mothers. We found that tadpoles hatch with a fully developed lateral line system. While begging behavior increases with development, ablating the lateral line system inhibited begging in pre-metamorphic tadpoles, but not in metamorphic tadpoles. We also found that the increase in begging and decrease in reliance on the lateral line co-occurs with increased retinal neural activity and gene expression associated with eye development. Using the neural tracer neurobiotin, we found that axonal innervations from the eye to the brain proliferate during metamorphosis, with few retinotectal connections in recently-hatched tadpoles. We then tested visual function in a phototaxis assay and found tadpoles prefer darker environments. The strength of this preference increased with developmental stage, but eyes were not required for this behavior, possibly indicating a role for the pineal gland. Together, these data suggest that tadpoles rely on different sensory modalities for social interactions across development and that the development of sensory systems in socially complex poison frog tadpoles is similar to that of other frog species.


Asunto(s)
Larva , Animales , Larva/fisiología , Metamorfosis Biológica/fisiología , Sistema de la Línea Lateral/fisiología , Comunicación Animal , Ranidae/fisiología , Visión Ocular/fisiología , Retina/fisiología
11.
Sci Rep ; 14(1): 14335, 2024 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-38906892

RESUMEN

Reintroduction efforts are increasingly used to mitigate biodiversity losses, but are frequently challenged by inadequate planning and uncertainty. High quality information about population status and threats can be used to prioritize reintroduction and restoration efforts and can transform ad hoc approaches into opportunities for improving conservation outcomes at a landscape scale. We conducted comprehensive environmental DNA (eDNA) and visual encounter surveys to determine the distribution of native and non-native aquatic species in two high-priority watersheds to address key uncertainties-such as the distribution of threats and the status of existing populations-inherent in restoration planning. We then used these occurrence data to develop a menu of potential conservation actions and a decision framework to benefit an endangered vertebrate (foothill yellow-legged frog, Rana boylii) in dynamic stream systems. Our framework combines the strengths of multiple methods, allowing managers and conservation scientists to incorporate conservation science and site-specific knowledge into the planning process to increase the likelihood of achieving conservation goals.


Asunto(s)
Conservación de los Recursos Naturales , ADN Ambiental , Ríos , Animales , Conservación de los Recursos Naturales/métodos , ADN Ambiental/análisis , Biodiversidad , Especies en Peligro de Extinción , Ecosistema , Ranidae/genética
12.
J Therm Biol ; 122: 103864, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38852487

RESUMEN

When amphibians thermoregulate, they face a fundamental trade-off between the ability to maintain activity and an increased rate of dehydration at higher temperatures. Canopy coverage affects both the thermal and hydric conditions of the environment and can therefore influence amphibian thermoregulation. Frogs require proper conditions to thermoregulate to successfully grow, survive, and reproduce. But while we know how canopy and environmental variables typically affect operative temperature, less is known about effects on amphibian water loss rates. In this study, we measure the effect of canopy coverage on the conditions available for thermoregulation at a breeding pond of the California red-legged frog, Rana draytonii. We use agar frog models to estimate the thermal and hydric capacities frogs would experience in locations with different canopy coverage and microhabitats. At each site, we deployed models under four microhabitat treatments: wet/sun, wet/shade, dry/sun, and dry/shade. We modeled how environmental variables affected operative temperature and evaporative water loss from agar frogs. We found positive effects of air temperature, the sun treatment, and reduced canopy cover on operative temperature, and negative direct or indirect effects of these variables on evaporative water loss, consistent with the hypothesized trade-off between thermoregulatory behavior to increase temperature and the increased desiccation risk due to higher water loss. Additionally, our results indicate that the availability of wet microhabitats can allow frogs to reduce water loss, potentially mitigating the risk of desiccation when thermoregulating to achieve higher operative temperatures. Our findings suggest, that with access to proper microhabitats, amphibians can mitigate the fundamental trade-off and receive benefits of thermoregulating at high temperatures.


Asunto(s)
Regulación de la Temperatura Corporal , Ecosistema , Animales , Ranidae/fisiología , Pérdida Insensible de Agua , Temperatura , Modelos Biológicos
13.
Integr Comp Biol ; 64(1): 15-26, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-38734888

RESUMEN

There is a large body of evidence linking increased noise to negative health effects for animals. Anthropogenic noise induces behavioral and physiological reactions across a range of taxa and increased traffic noise affects glucocorticoid (GC) hormones associated with the stress response in amphibians. GCs help to maintain homeostasis while balancing energetic trade-offs between reproduction, growth, and activity. Stressors during early development can impact fitness at later life stages. We measured growth, activity, and GCs in response to high levels of traffic noise in two tadpole species that differ in life history: Acris crepitans and Rana berlandieri. We predicted that earlier exposures to traffic noise will slow down the development and alter the behavior and GC concentrations differently than later exposures. Subjects were initially either exposed to natural levels of traffic noise for 8 days (early exposure) or a white noise control (later exposure), then the treatment was switched. Activity was measured via focal sampling and tadpoles were categorized as active if movement was detected. Tadpoles exposed to white noise initially maintained mass and activity throughout the experiment and early exposure to traffic noise had a greater impact on mass, activity, and GCs. Tadpoles exposed to traffic noise initially lost mass, with A. crepitans regaining mass but not R. berlandieri. When exposed earlier to traffic noise, R. berlandieri increased movement when shifted to the white noise treatment while A. crepitans did not significantly change activity. Acris creptians had higher corticosterone release rates compared to R. berlandieri, and in both species, release rates were higher for tadpoles exposed to noise earlier. The longer-lived R. berlandieri allocated more of their energetic resources into activity, while the shorter-lived A. crepitans allocated energy toward growth. Rana berlandieri and A. crepitans utilized different coping strategies to contend with early exposure to traffic noise, potentially due to differences in life histories. Our findings suggest that these tadpoles employ different coping mechanisms to modulate stress responses in noise-polluted environments, and these mechanisms could influence their fitness later in life. Further study is needed to understand the impact in more sensitive tadpole species.


Asunto(s)
Glucocorticoides , Larva , Animales , Larva/crecimiento & desarrollo , Larva/fisiología , Glucocorticoides/metabolismo , Ruido del Transporte/efectos adversos , Ranidae/fisiología , Ranidae/crecimiento & desarrollo , Especificidad de la Especie , Anuros/fisiología , Anuros/crecimiento & desarrollo , Corticosterona/metabolismo , Estrés Fisiológico
14.
Anal Biochem ; 692: 115548, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38697593

RESUMEN

Oviductus Ranae is the dried oviduct from Rana dybowskii, a forest frog species with medicinal, tonic, and cosmetic properties. Due to the high price and resource shortage, counterfeit varieties of Oviductus Ranae often appear in the market. However, traditional identification methods cannot accurately differentiate between Oviductus Ranae and its adulterants. In this study, a rapid molecular identification method has been established. The method involves extracting genomic DNA in just 30 s using filter paper purification, species-specific rapid polymerase chain reaction (PCR) amplification, and finally, fluorescence detection of the products. It can accurately identify Oviductus Ranae and its three common adulterants in about 30 min, making the process simple, fast, and highly specific.


Asunto(s)
Cartilla de ADN , Reacción en Cadena de la Polimerasa , Ranidae , Especificidad de la Especie , Animales , Ranidae/genética , Reacción en Cadena de la Polimerasa/métodos , Femenino , Oviductos/metabolismo , ADN/análisis , ADN/genética , ADN/aislamiento & purificación
15.
Environ Toxicol Chem ; 43(7): 1557-1568, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38695729

RESUMEN

Persistent organic pollutants pose a great threat to amphibian populations, but information on the bioaccumulation of contaminants in amphibians remains scarce. To examine the tissue distribution and maternal transfer of organic halogenated pollutants (OHPs) in frogs, seven types of tissues from black-spotted frog (muscle, liver, kidney, stomach, intestine, heart, and egg) were collected from an e-waste-polluted area in South China. Among the seven frog tissues, median total OHP concentrations of 2.3 to 9.7 µg/g lipid weight were found (in 31 polychlorinated biphenyl [PCB] individuals and 15 polybrominated diphenyl ether [PBDE], dechlorane plus [syn-DP and anti-DP], bexabromobenzene [HBB], polybrominated biphenyl] PBB153 and -209], and decabromodiphenyl ethane [DBDPE] individuals). Sex-specific differences in contaminant concentration and compound compositions were observed among the frog tissues, and eggs had a significantly higher contaminant burden on the whole body of female frogs. In addition, a significant sex difference in the concentration ratios of other tissues to the liver was observed in most tissues except for muscle. These results suggest that egg production may involve the mobilization of other maternal tissues besides muscle, which resulted in the sex-specific distribution. Different parental tissues had similar maternal transfer mechanisms; factors other than lipophilicity (e.g., molecular size and proteinophilic characteristics) could influence the maternal transfer of OHPs in frogs. Environ Toxicol Chem 2024;43:1557-1568. © 2024 SETAC.


Asunto(s)
Contaminantes Orgánicos Persistentes , Animales , Femenino , Distribución Tisular , Masculino , Contaminantes Orgánicos Persistentes/metabolismo , Monitoreo del Ambiente , Éteres Difenilos Halogenados/metabolismo , Anuros/metabolismo , China , Ranidae/metabolismo , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/análisis
16.
J Hazard Mater ; 474: 134729, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-38805811

RESUMEN

Climate change and human activities escalate the frequency and intensity of wildfires, threatening amphibian habitats and survival; yet, research on these impacts remains limited. Wildfire ash alters water quality, introduces contaminants, and may disrupt microbial communities, impacting gut and skin microbiota; however, the effects on gut and skin microbiota remain unclear. Rana dybowskii were exposed to five concentrations (0 g L-1, 1.25 g L-1, 2.5 g L-1, 5 g L-1, and 10 g L-1) of aqueous extracts of wildfire ashes (AEAs) for 30 days to assess AEAs' metal content, survival, and microbiota diversity via Illumina sequencing. Our results showed that the major elements in ash were Ca > K > Mg > Al > Fe > Na > Mn, while in AEA they were K > Ca > Na > Mg > As > Al > Cu. A significant decrease in amphibian survival rates with increased AEA concentration was shown. The beta diversity analysis revealed distinct shifts in microbiota composition. Notably, bacterial genera associated with potential health risks showed increased abundance in skin microbiota, emphasising the potential for ash exposure to affect amphibian health. Functional prediction analyses revealed significant shifts in metabolic pathways related to health and disease, indicating that wildfire ash exposure may influence amphibian health through changes in microbial functions. This study highlights the urgent need for strategies to mitigate wildfire ash impacts on amphibians, as it significantly alters microbiota and affects their survival and health.


Asunto(s)
Microbioma Gastrointestinal , Ranidae , Piel , Incendios Forestales , Animales , Piel/efectos de los fármacos , Piel/microbiología , Microbioma Gastrointestinal/efectos de los fármacos , Ranidae/microbiología , Microbiota/efectos de los fármacos , Bacterias/genética , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/metabolismo , Metales/toxicidad
17.
Environ Sci Technol ; 58(22): 9559-9569, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38710655

RESUMEN

Harmful cyanobacterial blooms are frequent and intense worldwide, creating hazards for aquatic biodiversity. The potential estrogen-like effect of Microcystin-LR (MC-LR) is a growing concern. In this study, we assessed the estrogenic potency of MC-LR in black-spotted frogs through combined field and laboratory approaches. In 13 bloom areas of Zhejiang province, China, the MC-LR concentrations in water ranged from 0.87 to 8.77 µg/L and were correlated with sex hormone profiles in frogs, suggesting possible estrogenic activity of MC-LR. Tadpoles exposed to 1 µg/L, an environmentally relevant concentration, displayed a female-biased sex ratio relative to controls. Transcriptomic results revealed that MC-LR induces numerous and complex effects on gene expression across multiple endocrine axes. In addition, exposure of male adults significantly increased the estradiol (E2)/testosterone (T) ratio by 3.5-fold relative to controls. Downregulation of genes related to male reproductive endocrine function was also identified. We also showed how MC-LR enhances the expression of specific estrogen receptor (ER) proteins, which induce estrogenic effects by activating the ER pathway and hypothalamic-pituitary-gonadal (HPG) axis. In aggregate, our results reveal multiple lines of evidence demonstrating that, for amphibians, MC-LR is an estrogenic endocrine disruptor at environmentally relevant concentrations. The data presented here support the need for a shift in the MC-LR risk assessment. While hepatoxicity has historically been the focus of MC-LR risk assessments, our data clearly demonstrate that estrogenicity is a major mode of toxicity at environmental levels and that estrogenic effects should be considered for risk assessments on MC-LR going forward.


Asunto(s)
Estrógenos , Animales , Masculino , Femenino , Microcistinas/toxicidad , Ranidae/genética , Ranidae/metabolismo , Toxinas Marinas , Contaminantes Químicos del Agua/toxicidad
18.
Aquat Toxicol ; 272: 106945, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38759526

RESUMEN

Human impacts on ecological communities are pervasive and species must either move or adapt to changing environmental conditions. For environments polluted by contaminants, researchers have found hundreds of target pest species evolving increased tolerance, but we have substantially fewer cases of evolved tolerance in non-target species. When species do evolve increased tolerance, inducible tolerance can provide immediate protection and favor the evolution of increased tolerance over generations via genetic assimilation. Using a model larval amphibian (wood frogs, Rana sylvatica), we examined the tolerance of 15 populations from western Pennsylvania and eastern New York (USA), when first exposed to no pesticide or sublethal concentrations and subsequently exposed to lethal concentrations of three common insecticides (carbaryl, chlorpyrifos, and diazinon). We found high variation in naïve tolerance among the populations for all three insecticides. We also discovered that nearly half of the populations exhibited inducible tolerance, though the degree of inducible tolerance (magnitude of tolerance plasticity; MoTP) varied. We observed a cross-tolerance pattern of the populations between chlorpyrifos and diazinon, but no pattern of similar MoTP among the pesticides. With populations combined from two regions, increased tolerance was not associated with proximity to agricultural fields, but there were correlations between proximity to agriculture and MoTP. Collectively, these results suggests that amphibian populations possess a wide range of naïve tolerance to common pesticides, with many also being able to rapidly induce increased tolerance. Future research should examine inducible tolerance in a wide variety of other taxa and contaminants to determine the ubiquity of these responses to anthropogenic factors.


Asunto(s)
Carbaril , Cloropirifos , Diazinón , Insecticidas , Animales , Insecticidas/toxicidad , Cloropirifos/toxicidad , Diazinón/toxicidad , Carbaril/toxicidad , Contaminantes Químicos del Agua/toxicidad , Larva/efectos de los fármacos , Ranidae , Pennsylvania , New York , Tolerancia a Medicamentos
19.
PeerJ ; 12: e17307, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38742097

RESUMEN

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents-including multiple parts of North America-due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa-which produce a powerful neurotoxin tetrodotoxin (TTX)-may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis.


Asunto(s)
Señales (Psicología) , Especies Introducidas , Salamandridae , Xenopus laevis , Animales , Washingtón , Salamandridae/fisiología , Larva , Conducta Predatoria , Ranidae
20.
BMC Genomics ; 25(1): 363, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38609871

RESUMEN

BACKGROUND: Cold hardiness is fundamental for amphibians to survive during the extremely cold winter on the Qinghai-Tibet plateau. Exploring the gene regulation mechanism of freezing-tolerant Rana kukunoris could help us to understand how the frogs survive in winter. RESULTS: Transcriptome of liver and muscle of R. kukunoris collected in hibernation and spring were assisted by single molecule real-time (SMRT) sequencing technology. A total of 10,062 unigenes of R. kukunoris were obtained, and 9,924 coding sequences (CDS) were successfully annotated. Our examination of the mRNA response to whole body freezing and recover in the frogs revealed key genes concerning underlying antifreeze proteins and cryoprotectants (glucose and urea). Functional pathway analyses revealed differential regulated pathways of ribosome, energy supply, and protein metabolism which displayed a freeze-induced response and damage recover. Genes related to energy supply in the muscle of winter frogs were up-regulated compared with the muscle of spring frogs. The liver of hibernating frogs maintained modest levels of protein synthesis in the winter. In contrast, the liver underwent intensive high levels of protein synthesis and lipid catabolism to produce substantial quantity of fresh proteins and energy in spring. Differences between hibernation and spring were smaller than that between tissues, yet the physiological traits of hibernation were nevertheless passed down to active state in spring. CONCLUSIONS: Based on our comparative transcriptomic analyses, we revealed the likely adaptive mechanisms of R. kukunoris. Ultimately, our study expands genetic resources for the freezing-tolerant frogs.


Asunto(s)
Respuesta al Choque por Frío , Transcriptoma , Animales , Respuesta al Choque por Frío/genética , Tibet , Perfilación de la Expresión Génica , Ranidae/genética , Anuros
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