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Chemical pollution, land cover change, and climate change have all been established as important drivers of amphibian reproductive success and phenology. However, little is known about the relative impacts of these anthropogenic stressors, nor how they may interact to alter amphibian population dynamics. Addressing this gap in our knowledge is important, as it allows us to identify and prioritise the most needed conservation actions. Here, we use long-term datasets to investigate landscape-scale drivers of variation in the reproductive success and phenology of UK Common frog (Rana temporaria) populations. Consistent with predictions, we found that increasing mean temperatures resulted in earlier initialisation of spawning, and earlier hatching, but these relationships were not consistent across all sites. Lower temperatures were also linked to increased spawn mortality. However, temperature increases were also strongly correlated with increases in urban area, arable area, and nitrate levels in the vicinity of spawning grounds. As with spawning and hatching, there was marked spatial variation in spawn mortality trends, where some sites exhibited steady increases over time in the proportion of dead or diseased spawn. These findings support previous work linking warming temperatures to shifts in timing of amphibian breeding, but also highlight the importance of assessing the effect of land use change and pollution on wild amphibian populations. These results have implications for our understanding of the response of wild amphibian populations to climate change, and the management of human-dominated landscapes for declining wildlife populations. [ABSTRACT FROM AUTHOR]

Chemical pollution, land cover change, and climate change have all been established as important drivers of amphibian reproductive success and phenology. However, little is known about the relative impacts of these anthropogenic stressors, nor how they may interact to alter amphibian population dynamics. Addressing this gap in our knowledge is important, as it allows us to identify and prioritise the most needed conservation actions. Here, we use long-term datasets to investigate landscape-scale drivers of variation in the reproductive success and phenology of UK Common frog (Rana temporaria) populations. Consistent with predictions, we found that increasing mean temperatures resulted in earlier initialisation of spawning, and earlier hatching, but these relationships were not consistent across all sites. Lower temperatures were also linked to increased spawn mortality. However, temperature increases were also strongly correlated with increases in urban area, arable area, and nitrate levels in the vicinity of spawning grounds. As with spawning and hatching, there was marked spatial variation in spawn mortality trends, where some sites exhibited steady increases over time in the proportion of dead or diseased spawn. These findings support previous work linking warming temperatures to shifts in timing of amphibian breeding, but also highlight the importance of assessing the effect of land use change and pollution on wild amphibian populations. These results have implications for our understanding of the response of wild amphibian populations to climate change, and the management of human-dominated landscapes for declining wildlife populations.

The study is devoted to the morphological features of the common frog of the Carpathian region of Ukraine, namely the expression, directionality and structure of sexual differences of this species. The work uses data obtained as a result of the processing of the scientific collection of Rana temporaria (Linnaeus, 1758) from the territory of the Ukrainian Carpathians (Lviv, Ivano-Frankivsk, and Zakarpattia oblasts), which is housed at the National Museum of Natural History, National Academy of Sciences of Ukraine (Kyiv). A total of 381 common frog specimens were studied—233 males (L = 24.6–84.5 mm) and 148 females (L = 23.2–94.2 mm). It is shown that individual differences in linear dimensions and body proportions in a sample of common frog males and females are structured and clearly reflect the morphological differentiation of individuals according to the age criterion. In the late ontogenesis of the common frog, generalised sex-related differences extend with the increasing age of individuals: in juveniles SqMD = 2.36, in subadults SqMD = 4.77, and in adults SqMD = 22.08. At the same time, not only does the expression of sex-related differences increase, but also their orientation changes significantly. According to our data, this year’s juveniles (juvenis) are individuals that did not winter at all (0+). At the same time, males are reliably (t = 4.50; p < 0.001) larger in body length (24.6–37.5 mm; Lmean = 29.87 mm) than females (23.2–32.7 mm; Lmean = 26.40 mm). But already in the group of semi-adult (subadultus) frogs, the orientation of sexual dimorphism in terms of body length changes completely—females are reliably larger than males, which is even more pronounced in adult, sexually mature individuals. Males of tailless amphibians grow and physiologically mature faster than females, so they begin to reproduce 1–2 years earlier. Females, which grow more slowly and mature later, join the reproduction having a larger size and older age. It is shown that sexual differences begin to form in the subadultus group. The generalised differences (SqMD) by sex are significantly smaller than by age. Adult sexually mature females compared to males are characterised by larger values of 18 body parameters, except for shoulder length (H.) and elbow joint diameter (Cr.a.c.), which are most reliably larger in males. These features of the proportions of the limbs provide the male with reliable holding of the female during mating (amplexus).

Ranid herpesvirus 3 (RaHV3) is a recently discovered virus associated with skin disease in frogs. We detected RaHV3 DNA in free-ranging common frog (Rana temporaria) tadpoles, consistent with premetamorphic infection. Our finding reveals a critical aspect of RaHV3 pathogenesis, relevant for amphibian ecology and conservation and, potentially, for human health.

Ranaviruses have been involved in amphibian mass mortality events worldwide. Effective screening to control this pathogen is essential; however, current sampling methods are unsuitable for the detection of subclinical infections. Non-lethal screening is needed to prevent both further spread of ranavirus and losses of at-risk species. To assess non-lethal sampling methods, we conducted two experiments: bath exposing common frogs to RUK13 ranavirus at three concentrations, and exposing common toads to RUK13 or PDE18. Non-lethal sampling included buccal, digit, body and tank swabs, along with toe clips and stool taken across three time-points post-exposure. The presence/load of ranavirus was examined using quantitative PCR in 11 different tissues obtained from the same euthanised animals (incl. liver, gastro-intestinal tract and kidney). Buccal swab screening had the highest virus detection rate in both species (62% frogs; 71% toads) and produced consistently high virus levels compared to other non-lethal assays. The buccal swab was effective across multiple stages of infection and differing infection intensities, though low levels of infection were more difficult to detect. Buccal swab assays competed with, and even outperformed, lethal sampling in frogs and toads, respectively. Successful virus detection in the absence of clinical signs was observed (33% frogs; 50% toads); we found no difference in detectability for RUK13 and PDE18. Our results suggest that buccal swabbing could replace lethal sampling for screening and be introduced as standard practice for ranavirus surveillance. [ABSTRACT FROM AUTHOR]

The purpose of the research is comparing abundance levels of blood-sucking dipterans in the forest-steppe zone of the Tyumen Region for 8 years with different meteorological conditions.Materials and methods. The studies were carried out in 2006 and 2013–2019 in vicinity of the villages of Isetskoe and Barkhatovo, Isetsky District, Tyumen Region. Tabanid flies were collected and counted using funnel-shaped traps permanently on the same pasture on a regular basis once every 5–7 days during the entire emergence period. When counting the number of mosquitoes, midges and sandflies, we used a net with removable bags. Each count included 10 sweeps with a motion of the figure eight "around itself" in 10 replications.Results and discussion. The abundance of blood-sucking dipterans is largely determined by natural and climatic conditions and a hydrological regime of rivers, and is liable to significant fluctuations. The maximum abundance of gnats was recorded in 2014, the minimum in 2006. In comparing the average number for seasons with maximum and minimum abundance, a difference of 3.7 times was found. The abundance level and ratio of individual components of the midges complex depending on the season also underwent significant changes. In collected insects, midges dominated in 2006 and 2014, and mosquitoes in 2013 and in 2015–2019. Meteorological and hydrological conditions in winter and spring had the biggest impact on the abundance level of insects of the midges complex. Fluctuations in the abundance were 9 times for mosquitoes, 20 times for tabanid flies, and 39 times for midges and sandflies depending on the season. The main limiting factors for mass development of blood-sucking Diptera in the forest-steppe zone of the Tyumen Region are hard and dry winters which cause death of some insects at the preimaginal stages in development, as well as sharp changes in air temperature in the spring-summer period and small areas of breeding places.

The purpose of the research is to study the parasite fauna of the common frog (Rana temporaria Linnaeus, 1758) inhabiting the vicinity of the Visim Nature Biosphere Reserve.Materials and methods. The species composition, dominance structure and endoparasite infection of 32 individuals of R. temporaria caught along the banks of the upper reaches of the Sulem Riverwere assessed according to the following indicators: the prevalence and intensity of infection and abundance index.Results and discussion. The species composition of parasites in a common frog from the vicinity of the Visim Nature Biosphere Reserve is presented for the first time. Five species of macroparasites have been identified, classified as Nematoda: Oswaldocruzia filiformis (Goeze, 1782), Neoraillietnema praeputiale (Skrjabin, 1916), Cosmocerca ornata (Dujardin, 1845), Rhabdias bufonis (Schrank, 1788) and as Platyhelminthes: Haplometra cylindracea (Zeder, 1800). One species of endosymbiotic protozoa of Chromista, Opalina ranarum was recorded (Purkinje et Valentin, 1835). The prevalence of the infection of common frogs by helminths reaches 100%, the abundance index is 11.06, and protozoa is 93.8% and 62.16, respectively. Nematodes O. filiformis (the prevalence of infection 96.9%, and abundance index 7.97) and R. bufonis (the prevalence of infection 46.9%, abundance index 2.28) predominate. It was shown that nematode N. praeputiale was not found in the parasitocenosis of immature amphibians, and trematode H. cylindracea was not found in adult animals. The proportion of O. filiformis and C. ornata increases with age in common frogs. It was found that the animals of the July population are infected with nematode R. bufonis largely. Regardless of the age of R. temporaria, the probability of colonization by O. ranarum in spring will be higher.

We present a genome assembly from an individual female Rana temporaria (the common frog; Chordata; Amphibia; Anura; Ranidae). The genome sequence is 4.11 gigabases in span. The majority of the assembly is scaffolded into 13 chromosomal pseudomolecules. Gene annotation of this assembly by the NCBI Eukaryotic Genome Annotation Pipeline has identified 23,707 protein coding genes.

The presence of Rana temporaria on Turin Hills (Piedmont NW Italy) has been confirmed through morphological and molecular analyses. Breeding individuals of this species were found at two sites and assessed by either morpho-chromatic and genetics. This new finding represents an interesting confirmation of ancient record reported in 1877 by the renowned naturalist Michele Lessona, and highlights that the species is likely quite cryptical and secretive and has a distribution wider than formerly presumed.

The presence of Rana temporaria on Turin Hills (Piedmont NW Italy) has been confirmed through morphological and molecular analyses. Breeding individuals of this species were found at two sites and assessed by either morpho-chromatic and genetics. This new finding represents an interesting confirmation of ancient record reported in 1877 by the renowned naturalist Michele Lessona, and highlights that the species is likely quite cryptical and secretive and has a distribution wider than formerly presumed. [ABSTRACT FROM AUTHOR]

The global trend of increasing environmental temperatures is often predicted to result in more severe disease epidemics. However, unambiguous evidence that temperature is a driver of epidemics is largely lacking, because it is demanding to demonstrate its role among the complex interactions between hosts, pathogens, and their shared environment. Here, we apply a three‐pronged approach to understand the effects of temperature on ranavirus epidemics in UK common frogs, combining in vitro, in vivo, and field studies. Each approach suggests that higher temperatures drive increasing severity of epidemics. In wild populations, ranavirosis incidents were more frequent and more severe at higher temperatures, and their frequency increased through a period of historic warming in the 1990s. Laboratory experiments using cell culture and whole animal models showed that higher temperature increased ranavirus propagation, disease incidence, and mortality rate. These results, combined with climate projections, predict severe ranavirosis outbreaks will occur over wider areas and an extended season, possibly affecting larval recruitment. Since ranaviruses affect a variety of ectothermic hosts (amphibians, reptiles, and fish), wider ecological damage could occur. Our three complementary lines of evidence present a clear case for direct environmental modulation of these epidemics and suggest management options to protect species from disease. [ABSTRACT FROM AUTHOR]

Amphibian populations have been declining globally over the past decades. The intensification of agriculture, habitat loss, fragmentation of populations and toxic substances in the environment are considered as driving factors for this decline. Today, about 50% of the area of Germany is used for agriculture and is inhabited by a diverse variety of 20 amphibian species. Of these, 19 are exhibiting declining populations. Due to the protection status of native amphibian species, it is important to evaluate the effect of land use and associated stressors (such as road mortality and pesticide toxicity) on the genetic population structure of amphibians in agricultural landscapes. We investigated the effects of viniculture on the genetic differentiation of European common frog (Rana temporaria) populations in Southern Palatinate (Germany). We analyzed microsatellite data of ten loci from ten breeding pond populations located within viniculture landscape and in the adjacent forest block and compared these results with a previously developed landscape permeability model. We tested for significant correlation of genetic population differentiation and landscape elements, including land use as well as roads and their associated traffic intensity, to explain the genetic structure in the study area. Genetic differentiation among forest populations was significantly lower (median pairwise FST = 0.0041 at 5.39 km to 0.0159 at 9.40 km distance) than between viniculture populations (median pairwise FST = 0.0215 at 2.34 km to 0.0987 at 2.39 km distance). Our analyses rejected isolation by distance based on roads and associated traffic intensity as the sole explanation of the genetic differentiation and suggest that the viniculture landscape has to be considered as a limiting barrier for R. temporaria migration, partially confirming the isolation of breeding ponds predicted by the landscape permeability model. Therefore, arable land may act as a sink habitat, inhibiting genetic exchange and causing genetic differentiation of pond populations in agricultural areas. In viniculture, pesticides could be a driving factor for the observed genetic impoverishment, since pesticides are more frequently applied than any other management measure and can be highly toxic for terrestrial life stages of amphibians.

The early detection and identification of pathogenic microorganisms is essential in order to deploy appropriate mitigation measures. Viruses in the Iridoviridae family, such as those in the Ranavirus genus, can infect amphibian species without resulting in mortality or clinical signs, and they can also infect other hosts than amphibian species. Diagnostic techniques allowing the detection of the pathogen outside the period of host die-off would thus be of particular use. In this study, we tested a method using environmental DNA (eDNA) on a population of common frogs (Rana temporaria) known to be affected by a Ranavirus in the southern Alps in France. In six sampling sessions between June and September (the species’ activity period), we collected tissue samples from dead and live frogs (adults and tadpoles), as well as insects (aquatic and terrestrial), sediment, and water. At the beginning of the breeding season in June, one adult was found dead; at the end of July, a mass mortality of tadpoles was observed. The viral DNA was detected in both adults and tadpoles (dead or alive) and in water samples, but it was not detected in insects or sediment. In live frog specimens, the virus was detected from June to September and in water samples from August to September. Dead tadpoles that tested positive for Ranavirus were observed only on one date (at the end of July). Our results indicate that eDNA can be an effective alternative to tissue/specimen sampling and can detect Ranavirus presence outside die-offs. Another advantage is that the collection of water samples can be performed by most field technicians. This study confirms that the use of eDNA can increase the performance and accuracy of wildlife health status monitoring and thus contribute to more effective surveillance programs.

The common frog (Rana temporaria) has been the focus of several broadscale phylogeographic studies, revealing a deep split between eastern and western European populations, most likely induced by the onset of the Pleistocene glaciations. However, the identification of glacial refugia, as well as the understanding of recolonization processes and their genetic legacy remain far from complete. A recent survey on Italian populations revealed a previously unrecognized Pleistocene refuge in the Italian peninsula and suggested the hypothesis of multiple separated microrefugia ('refugia-within refugia' model), but fine-scale studies required to confirm this hypothesis are lacking. We examined the phylogeographic structure of 54 common frog populations (540 individuals) by means of COI (cytochrome oxidase I) mitochondrial gene, focusing on a south-eastern Alpine region (Trentino, Italy) with an intensive sampling design. Phylogeographical reconstruction indicated the presence of three different COI lineages, exhibiting different levels of genetic diversity, and a contact zone in the eastern part of the region. Our data supported the scenario of multiple sub-refugia, probably located in the southern slopes of the Alpine chain, where the species survived the ice ages in fragmented populations. The recorded patterns are explained by the biogeographic peculiarity of the study region. [ABSTRACT FROM AUTHOR]

The objective of this work consists in valuing the carob pods (very rich in sugars and in nourishing elements) as being a medium of culture for growth of Lactobacillus bulgaricus and comparison this natural syrup with MRS medium for lactic acid production curve. By its biochemical composition, the carob syrup is very rich in carbohydrates 16 g/L, protein 0.25 %, ash 0.8 % including potassium (110 mg/100 mL of MF), sodium (80) and calcium (150). Kinetics study of growth of Lactobacillus bulgaricus in MRS and carob pods syrup showed that high biomass and lactic acid were obtained in the end of carob fermentations respectively (5.51 and 13.8) compared to MRS fermentation (4.57 and 10.9). This study clearly showed that carob pods have potential to be used as feedstock for lactic acid production by Lactobacillus bulgaricus using batch culture. [ABSTRACT FROM AUTHOR]

High-latitude species (and populations within species) are adapted to short and cold summers. They often have high growth and development rates to fully use the short growing season and mature before the onset of winter., Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life-history adaptations to their molecular consequences in body nutrient composition in Rana temporaria tadpoles., Temperature and food quality were manipulated during the development of tadpoles from Arctic and Boreal origins. We determined tadpole growth rate, development rate, body size and nutrient content, to test whether (i) Arctic tadpoles could realize higher growth rates and development rates with the help of higher-quality food even when food quantity was unchanged, (ii) Arctic and Boreal tadpoles differed in their stoichiometric (and life history) response to temperature changes, (iii) higher growth rates lead to higher tadpole P content (growth rate hypothesis) and (iv) allometric scaling affects tadpole nutrient allocation., We found that especially Arctic tadpoles grew and developed faster with the help of higher-quality food and that tadpoles differed in their stoichiometric (and life history) response to temperature changes depending on region of origin (probably due to different temperature optima). There was no evidence that higher growth rates mediated the positive effect of temperature on tadpole P content. On the contrary, the covariate growth rate was negatively connected with tadpole P content (refuting the growth rate hypothesis). Lastly, tadpole P content was not related to body size, but tadpole C content was higher in larger tadpoles, probably due to increased fat storage., We conclude that temperature had a strong effect on tadpole life history, nutrient demand and stoichiometry and that this effect depended on the evolved life history. [ABSTRACT FROM AUTHOR]

We studied population size, genetic diversity and differentiation of common frog ( Rana temporaria) populations at urban golf courses and reference natural ponds in the greater Helsinki region, southern Finland. A total of 248 tadpoles from 12 locations (six golf courses, six reference sites) were genotyped with 13 polymorphic microsatellite markers. The most urban populations, situated in northern Helsinki, were the largest breeding sites having >120 (golf courses) and >200 (reference sites) spawn clumps at the time of sampling. On average, there was no difference in the number of spawns between the anthropogenic ponds at golf courses and the natural water bodies. Genetic variation within populations was substantial ( H = 0.68) while genetic differentiation between populations was low ( F = 0.016; average distance = 17.6 km). The golf course populations did not differ from natural populations in terms of genetic variability or differentiation. Hence, our results suggest that golf courses contribute positively to urban amphibian populations by providing suitable water bodies for reproduction and green corridors for dispersal, thus preventing isolation and loss of genetic variability within populations. [ABSTRACT FROM AUTHOR]

Non-invasive DNA sampling is an important tool in amphibian conservation. Buccal swabs are nowadays replacing the wounding toe-clipping method. Skin and cloaca swabbing are even less invasive and easier to handle than buccal swabbing, but could result in contaminations of genetic material. Therefore, we test if external skin and cloaca swabs are as reliable as buccal swabs for genetic analysis of amphibians. We analysed eight microsatellite loci for the common frog ( Rana temporaria, Linnaeus 1758) and compared genotyping results for buccal, skin and cloaca swabs regarding allelic dropouts and false alleles. Furthermore, we compared two DNA extraction methods regarding efficiency and cost. DNA quality and quantity (amplification success, genotyping error rate, in nanogram per microlitre) were comparable among DNA sources and extraction methods. However, skin and cloaca samples exhibited high degrees of contamination with foreign individuals, which was due to sample collection during mating season. Here, we established a simple low budget procedure to receive DNA of amphibians avoiding stressful buccal swabbing or harmful toe clipping. However, the possibility of contaminations of external swabs has to be considered. [ABSTRACT FROM AUTHOR]

Graph-based analysis is a promising approach for analyzing the functional and structural connectivity of landscapes. In human-shaped landscapes, species have become vulnerable to land degradation and connectivity loss between habitat patches. Movement across the landscape is a key process for species survival that needs to be further investigated for heterogeneous human-dominated landscapes. The common frog ( Rana temporaria) was used as a case study to explore and provide a graph connectivity analysis framework that integrates habitat suitability and dispersal responses to landscape permeability. The main habitat patches influencing habitat availability and connectivity were highlighted by using the software Conefor Sensinode 2.2. One of the main advantages of the presented graph-theoretical approach is its ability to provide a large choice of variables to be used based on the study's assumptions and knowledge about target species. Based on dispersal simulation modelling in potential suitable habitat corridors, three distinct patterns of nodes connections of differing importance were revealed. These patterns are locally influenced by anthropogenic barriers, landscape permeability, and habitat suitability. And they are affected by different suitability and availability gradients to maximize the best possible settlement by the common frog within a terrestrial habitat continuum. The study determined the key role of landscape-based approaches for identifying the 'availability-suitability-connectivity' patterns from a local to regional approach to provide an operational tool for landscape planning. [ABSTRACT FROM AUTHOR]

Male mating success is generally governed by either female choice or male–male competition and multiple cues may influence both processes. Anuran amphibians are best known for acoustic communication but visual cues have also been found to play a role. Little is known, however, about visual cues in explosively breeding anurans in which sexual selection is based almost exclusively on male–male competition. During their search for mates, males may not distinguish between the sexes or species and mismating attempts are known to occur. Assuming that mismatings are costly for males, one would expect selection to favour a trait that facilitates sex recognition. We determined the colour of the explosively breeding common frog, Rana temporaria, during reproduction by spectrophotometry. While reflectance of all body parts in both sexes decreased from immigration to spawning, reflectance of male throats increased significantly. The mean luminance of male throats was more than twice that of female throats. Male throats contrasted most against male flanks with luminance contrast being significantly higher than chromatic contrast. In an experiment with individually marked frogs, throat luminance was not correlated with male size, body condition or the physical presence of females, whereas temperature showed a significantly positive effect. Our results give no hint that throats indicate male status or indicate male quality. Considering the high densities during breeding, our results suggest that bright male throats can act as a visual signal among males to facilitate gender recognition and avoid attacks by other males. [Copyright &y& Elsevier]

High-density conditions often result in some individuals becoming stunted, when their growth and development are halted. When conditions improve such individuals may be capable of restarting these processes (recovery growth). Stage-specific recovery growth rates were studied in stunted larvae of Rana temporaria which were removed from high density laboratory cultures, reared individually and fed adequately. Tadpoles originated from two montane populations in southern Poland (Babia Gora range and the Tatra Mountains near Zakopane). During 14 days of rapid growth, the Babia Gora larvae fed at high-food level gained on average 167% of body mass; at lower food level the larvae which started recovery growth at Gosner's stages 34-35 had significantly lower daily relative growth rates than the larvae which started at earlier developmental stages (Gosner's 30-32). The Tatra Mountains larvae showed similar pattern: during the 4-day feeding period, larvae gained 44% of body mass, but individuals which were at the beginning at stage 37 grew at the rate 17% lower than those at stages 32-35. In a separate experiment on Rana sylvatica tadpoles from New England, U.S., the initially stunted larvae increased, on average, almost 6-fold in body mass during two weeks of intense growth following the removal from high density cultures. Developmental arrest preserves the potential of the stunted Rana larvae for very fast growth, allowing them to capitalize on transient improvement of living conditions. However, there is a steady decline in the potential for such growth spurt with increasing advancement of ontogenetic development. [ABSTRACT FROM AUTHOR]

Abstract: Using the European common frog, Rana temporaria, as a model, we have studied the organ-specific gene expression patterns of thyroid hormone receptor isoforms after exposure to an organochlorine (OC) compound, p,p′-DDE. Four groups of frogs were subcutaneously injected with p,p′-DDE at 0.01, 0.1, 1 and 10mg/kg body weight, respectively. In addition, one group, serving as the control group, was injected with pure corn oil. TH receptor isoforms (TRα and TRβ) gene expressions were evaluated in the brain, kidney, testis and liver using real-time PCR with gene-specific primers. Our results show that p,p′-DDE doses induced slight elevations of TRα and TRβ mRNA in the brain. In the testis, p,p′-DDE induced an initial significant 3-fold increase of TRα mRNA at 0.01mg/kg and thereafter clear dose-dependent decreases of TRα mRNA levels were observed. For testicular TRβ mRNA levels, p,p′-DDE induced a slight elevation at 0.01mg/kg and thereafter significant decreases in TRβ mRNA levels were observed. p,p′-DDE induced significant 2–4-fold elevations of both TR isoforms in frog kidney. The strongest transcriptional effect of p,p′-DDE on TR isoforms was observed in the kidney. While TRα mRNA was not measurable in the liver, p,p′-DDE induced an initial 1.7-fold increase at 0.01mg/kg of TRβ mRNA and thereafter an apparent dose-dependent decrease was observed. The relative abundance of TRα and TRβ gene expression in different organs are in the order: kidney>testis>brain>liver. While the induction TRα and TRβ might result to hypersensitivity and subsequent gain of biological functions, the inhibition might result to loss of biological function. Given the high persistency in the environment and continued use in developing countries coupled with the tendency for global atmospheric transport, DDT and its metabolites such as p,p′-DDE will remain a focus of concern both for scientific and societal reasons. [Copyright &y& Elsevier]

The inhibitor of gap junctions 18α-glycerretinic acid inhibits the maturation of follicle-enclosed common frog oocytes stimulated by low progesterone concentrations. The inhibitory effect of 18α-glycyrrhetinic acid does not depend on concentrations within the limits of 5–40 μM. The progesterone concentrations, at which oocyte maturation can be inhibited, differed markedly in different females. The inhibitory effects of actinomycin D (5 μg/ml) and 18α-glycyrrhetinic acid (5 μg/ml) were expressed when the same progesterone concentrations were used. When injected in an intact oocyte, Lucifer yellow was transferred into the follicle cells, thus suggesting the presence of gap junction between these latter and the oocyte. The data obtained suggest that the previously described transcription-dependent factor formed in the follicle cells under the influence of low progesterone concentrations and stimulating oocyte maturation is transferred in the oocyte via gap junctions. [ABSTRACT FROM AUTHOR]

The major water-soluble polypeptide with molecular weight of approximately 23 kDa (the 23 kDa polypeptide) was identified in the lens of common frog Rana temporaria L. According to the gel filtration data, the peptide is a part of an oligomeric protein with molecular weight over than 300 kDa (α-crystallin fraction). A highly pure fraction of the 23 kDa polypeptide was isolated by two-step ion-exchange chromatography and SDS electrophoresis and the specific antibodies were obtained. Immunohistochemistry showed the presence of the 23 kDa polypeptide in the cytoplasm of lens epithelial cells (including its central region) and in the zones neighboring the plasma membranes in the cortical fibers. The 23 kDa polypeptide was not found in the lens central zone (nucleus). It was also present in the retina (in the cells of inner nuclear layers), but not in the other tissues and organs of adult frog. Immunochemical analysis showed that the 23 kDa polypeptide was different from all known crystallins of frogs and other animals (bull, mouse, rat, and chicken). The nature of the 23 kDa polypeptide and the relation of its expression with the lens cell differentiation are discussed. [ABSTRACT FROM AUTHOR]

Constructed wetlands are used as an effective measure to improve water quality and reduce nutrient runoff from agriculture. However, their role as alternative breeding sites for different amphibian species is rarely explored. We studied amphibians' colonization and breeding success in two in-stream free surface water wetlands in intensively managed agricultural landscape in south-eastern Estonia. Additionally, the sedimentation pond and a nearby farm pond were observed. The observations started a year after the establishment of the constructed wetlands in 2015 and lasted for four years. In Vända constructed wetlands, breeding of five amphibian species were observed, all of which were common to the area: smooth newt (Lissotriton vulgaris L.), common toad (Bufo bufo L.), common frog (Rana temporaria L.), moor frog (Rana arvalis Nilsson) and pool frog (Pelophylax lessonae Camerano). Threatened species, such as the common spadefoot toad (Pelobates fuscus Wagler) or the northern crested newt (Triturus cristatus Laur.), also present in this region, were not found in the study sites. Unlike the sedimentation and farm ponds, constructed wetlands with their shallow rapidly warming water and absence of fish, provided breeding habitat for amphibians, especially for common frog and moor frog. In addition, chemical analyses of the water showed that nutrient concentration in the surface water was relatively low, which should not impair the reproduction of amphibians, at least in the short-term. [ABSTRACT FROM AUTHOR]

The early detection and identification of pathogenic microorganisms is essential in order to deploy appropriate mitigation measures. Viruses in the Iridoviridae family, such as those in the Ranavirus genus, can infect amphibian species without resulting in mortality or clinical signs, and they can also infect other hosts than amphibian species. Diagnostic techniques allowing the detection of the pathogen outside the period of host die-off would thus be of particular use. In this study, we tested a method using environmental DNA (eDNA) on a population of common frogs (Rana temporaria) known to be affected by a Ranavirus in the southern Alps in France. In six sampling sessions between June and September (the species' activity period), we collected tissue samples from dead and live frogs (adults and tadpoles), as well as insects (aquatic and terrestrial), sediment, and water. At the beginning of the breeding season in June, one adult was found dead; at the end of July, a mass mortality of tadpoles was observed. The viral DNA was detected in both adults and tadpoles (dead or alive) and in water samples, but it was not detected in insects or sediment. In live frog specimens, the virus was detected from June to September and in water samples from August to September. Dead tadpoles that tested positive for Ranavirus were observed only on one date (at the end of July). Our results indicate that eDNA can be an effective alternative to tissue/specimen sampling and can detect Ranavirus presence outside die-offs. Another advantage is that the collection of water samples can be performed by most field technicians. This study confirms that the use of eDNA can increase the performance and accuracy of wildlife health status monitoring and thus contribute to more effective surveillance programs. [ABSTRACT FROM AUTHOR]

We developed seven microsatellite loci in the common frog, Rana temporaria. There were between 2 and 27 alleles per locus and the expected heterozygosities ranged from 0.28 to 0.96 in a sample of frogs collected in the French Alps. Adding these seven markers to the 15 previously available microsatellite loci for this species should facilitate studies of genetic structure of Rana temporaria populations at a fine geographical scale. [ABSTRACT FROM AUTHOR]