Lake Frog Research Articles

Исследование накопления радионуклидов озерной лягушкой (Pelophylax ridibundus Pall.) в водных экосистемах как индикатор антропогенного загрязнения

Accumulation of anthropogenic 90Sr and 137Cs radio nuclides in lake frog (Pelophylax ridibundus Pall.) in the subjected to anthropogenic pollution regions of Beloyarka and Verkhni Tagil reservoirs location, the Urals, has been investigated. Conduction of this research was caused by wide spreading of this amphibian species in water bodies, absence in literature any data on the lake frog radioecology, as well as by the fact that this research outcome can serve a good indicator of anthropogenic pollution. Levels of the radio nuclides accumulation by this frog in the Beloyarka nuclear power station industrial/storm water sewer characterized by the increased 90Sr and 137Cs discharge to the channel ecosystem have been determined. The Tagil River at the point of water discharge from the Verkhni Tagil reservoir (the Verkhni Tagil thermal power station basin cooler) was chosen as a reference point for comparison. Any reliable difference in radio nuclides accumulation depending on amphibian sex and age was not found. Comparative radio nuclides accumulation levels for lake frog in comparison with other species of aquatic ecosystem have been assessed. The industrial/storm water channel example has shown that 90Sr accumulation is decreasing in the following series: plankton > frogs, plants, ground > ichthyofauna, and for 137Cs: plankton > plants > frogs, ground > ichthyofauna. Содержание 137Cs content in animals from the channel appeared to be reliably lower than in the Tagil River. It was supposed that probably there was an unidentified source of amphibian radioactive contamination where from 137Cs was transferred to the Tagil River.

Morphogenesis of Vomeronasal Organ of Pelophylax ridibundus (Amphibia, Anura)

Abstract The morphogenesis of the lake frog (Pelophylax ridibundus) vomeronasal organ was studied during different ontogenesis stages. The vomeronasal organ is laid after the formation of olfactory sacs, which are lined by olfactory epithelium, and after choan formation. Vomeronasal organ anlage takes place during G24 stage of larval development, which is the result of inflection and cell redistribution of olfactory epithelium rostroventral part. Formation of the vomeronasal organ finished at the beginning of metamorphosis. Apparently, vomeronasal organ appeared in aquatic Amphibia ancestors and after their transition from aquatic to terrestrial environment it developed new adaptive functions

THE KARYOSPHERE IN LATE OOGENESIS OF FROGS

SUMMARY Late oogenesis of the lake frog Rana ridibunda Pallas, 1771 and Rana temporaria Linnaeus, 1758 was investigated by means of morphological and cytochemical methods. It was shown that in the period of late vitellogenesis during the autumn and winter months the nuclear structures (lampbrush chromosomes and multiple nucleoli) assemble in the centre of the nucleus occupying a large area (up to 180μ in diameter) and forming a karyosphere. Spherical nucleoli are located along the periphery of the karyosphere and they form the capsule of karyosphere. These nucleoli are supplied with thread-like granular structures. Nearer the centre of the karyosphere, typical lampbrush chromosomes are found. The centre of the karyosphere is occupied by a great number of polymorphous bodies and ring structures, containing DNA. Polymorphous bodies may reach from 5 to 30–50 μ in length and ring structures from 1 to 3 μ in diameter. It was shown that in the course of oogenesis the polymorphous bodies become substituted by th...

Bioindicator Estimation of Quality of Environment in Floodlands of the Rivers Oka and Ugra on Stability of Development of Lake Frogs ( Rana ridibunda )

A comparative analysis was made on the base of estimation of stability of development of lake frogs ( R. ridibunda ) to estimate the environmental quality. Stability of development was determined according to the level of fluctuating asymmetries. Methods giving opportunity to calculate the coefficient of asymmetry on the example of Kaluga region are described. The greatest value of the coefficient in the spots subjected to anthropogenous influence of populated areas is marked.

Cytological maps of lampbrush chromosomes of European water frogs (Pelophylax esculentuscomplex) from the Eastern Ukraine

BackgroundHybridogenesis (hemiclonal inheritance) is a kind of clonal reproduction in which hybrids between parental species are reproduced by crossing with one of the parental species. European water frogs (Pelophylax esculentus complex) represent an appropriate model for studying interspecies hybridization, processes of hemiclonal inheritance and polyploidization. P. esculentus complex consists of two parental species, P. ridibundus (the lake frog) and P. lessonae (the pool frog), and their hybridogenetic hybrid – P. esculentus (the edible frog). Parental and hybrid frogs can reproduce syntopically and form hemiclonal population systems. For studying mechanisms underlying the maintenance of water frog population systems it is required to characterize the karyotypes transmitted in gametes of parental and different hybrid animals of both sexes.ResultsIn order to obtain an instrument for characterization of oocyte karyotypes in hybrid female frogs, we constructed cytological maps of lampbrush chromosomes from oocytes of both parental species originating in Eastern Ukraine. We further identified certain molecular components of chromosomal marker structures and mapped coilin-rich spheres and granules, chromosome associated nucleoli and special loops accumulating splicing factors. We recorded the dissimilarities between P. ridibundus and P. lessonae lampbrush chromosomes in the length of orthologous chromosomes, number and location of marker structures and interstitial (TTAGGG)n-repeat sites as well as activity of nucleolus organizer. Satellite repeat RrS1 was mapped in centromere regions of lampbrush chromosomes of the both species. Additionally, we discovered transcripts of RrS1 repeat in oocytes of P. ridibundus and P. lessonae. Moreover, G-rich transcripts of telomere repeat were revealed in association with terminal regions of P. ridibundus and P. lessonae lampbrush chromosomes.ConclusionsThe constructed cytological maps of lampbrush chromosomes of P. ridibundus and P. lessonae provide basis to define the type of genome transmitted within individual oocytes of P. esculentus females with different ploidy and from various population systems.

Об оценке состояния окружающей среды по уровню флуктуирующей асимметрии у бесхвостых амфибий на примере озерной лягушки (Rana ridibunda)

Об оценке состояния окружающей среды по уровню флуктуирующей асимметрии у бесхвостых амфибий на примере озерной лягушки (Rana ridibunda)

Personality and metamorphosis: is behavioral variation consistent across ontogenetic niche shifts?

Understanding the manner by which individual differences in personality arise and are maintained in animal populations is currently a topic of considerable research interest. This is particularly the case when it comes to developmental processes and understanding how behaviors change over ontogeny. Such developmental perspectives are essential given that the vast majority of animal species possess complex life cycles or undergo some form of metamorphosis. Yet, in spite of the broad taxonomic relevance and the obvious potential importance of metamorphosis for understanding the basis of consistency in personality over ontogeny, almost no research has been done on this topic. Using the lake frog (Rana ridibunda) as a study organism, we tested whether individual-level differences in personality (activity, exploration and boldness) were consistent within both larval and juvenile frog life-history stages and across metamorphosis. We found that most behaviors of interest were highly consistent within a given life-history stage and at least some traits were consistent across metamorphosis (e.g., activity and exploration). Generally, more active, exploratory individuals in novel experimental arenas were also bolder and more likely to spend time in more risky open areas of a familiar environment. To our knowledge, our study is the first to both characterize personality traits across anuran development and provide evidence of consistency in behavior across metamorphosis in a vertebrate species.

Invasiveness of an introduced species: the role of hybridization and ecological constraints

Introduced species are confronted with new environments to which they need to adapt. However, the ecological success of an introduced species is generally difficult to predict, especially when hybridizations may be involved in the invasion success. In western Europe, the lake frog Pelophylax ridibundus appears to be particularly successful. A reason for this species’ success might be the presence of the invader’s genetic material prior to the introduction in the form of a hybrid between P. ridibundus and a second indigenous water frog species. These hybrids reproduce by hybridogenesis, only transmitting the ridibundus genome to gametes and backcrossing with the indigenous species (i.e. P. lessonae). This reproductive system allows the hybrid to be independent from P. ridibundus, and allows the ridibundus genome to be more widely spread than the species itself. Matings among hybrids produce newly formed P. ridibundus offspring (N), if the genomes are compatible. Therefore, we hypothesize that hybridogenesis increases the invasiveness of P. ridibundus (1) by enhancing propagule pressure through N individuals, and/or (2) by increasing adaptation of invaders to the native water frogs’ habitat through hybrid-derived ridibundus genomes that are locally adapted. We find support for the first hypothesis because a notable fraction of N tadpoles is viable. However, in our semi-natural experiments they did not outperform ridibundus tadpoles in the native water frogs’ habitat, nor did they differ physiologically. This does not support the second hypothesis and highlights ecological constraints on the invasion. However, we cannot rule out that these constraints may fall with ongoing selection, making a replacement of indigenous species highly probable in the future.

Comparative enzymological study of catalytic properties of liver monoamine oxidases in frogs

Comparative enzymological study of catalytical properties of monoamine oxidase (MAO) of liver of the lake frog Rana ridibunda and brown frog Rana temporaria has revealed certain features of similarity and differences between these enzymes. The MAOs from both studied biological sources show catalytic properties resembling those of the classical MAO of terrestrial vertebrates: they deaminate tyramine, tryptamine, serotonin, benzylamine and do not deaminate histamine, have sensitivity to chlorgiline, the specific inhibitor of the MAO A form, and deprenyl, the specific inhibitor of the MAO B form, and are not inhibited with 10(-2) M semicarbazide. Based on data of substrate-inhibitor analysis, a suggestion is put forward about the existence of two molecular forms of the enzyme in liver of the studied frog species. Interspecies quantitative differences have been revealed between liver MAO of Rana ridibunda and Rana temporaria in values of kinetic parameters of reactions of deamination of several substrates and in sensitivity to the inhibitors, deprenyl and clorgyline. In the species Rana temporaria the MAO activity in reaction of deamination of serotonin and benzylamine were practically identical, whereas in the species Rana ridibunda these parameters for serotonin were almost one order of magnitude higher than for benzylamine. For the species Rana ridibunda, selectivity of action of deprenyl was expressed many times weaker while selectivity of the chlorgiline--one order of magnitude stronger than for the species Rana temporaria. The catalytic activity for all studies substrates of liver MAO of both studied amphibian species were several times lower as compared with the enzyme of rat liver.

Phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs were determined by geological processes and climate change in the Late Cenozoic

AIM: Our aims were to assess the phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs and to estimate divergence times using different geological scenarios. We related divergence times to past geological events and discuss the relevance of our data for the systematics of eastern Mediterranean water frogs. LOCATION: The eastern Mediterranean region. METHODS: Genetic diversity and divergence were calculated using sequences of two protein-coding mitochondrial (mt) genes: ND2 (1038 bp, 119 sequences) and ND3 (340 bp, 612 sequences). Divergence times were estimated in a Bayesian framework under four geological scenarios representing alternative possible geological histories for the eastern Mediterranean. We then compared the different scenarios using Bayes factors and additional geological data. RESULTS: Extensive genetic diversity in mtDNA divides eastern Mediterranean water frogs into six main haplogroups (MHG). Three MHGs were identified on the Anatolian mainland; the most widespread MHG with the highest diversity is distributed from western Anatolia to the northern shore of the Caspian Sea, including the type locality of Pelophylax ridibundus. The other two Anatolian MHGs are restricted to south-eastern Turkey, occupying localities west and east of the Amanos mountain range. One of the remaining three MHGs is restricted to Cyprus; a second to the Levant; the third was found in the distribution area of European lake frogs (P. ridibundus group), including the Balkans. MAIN CONCLUSIONS: Based on geological evidence and estimates of genetic divergence we hypothesize that the water frogs of Cyprus have been isolated from the Anatolian mainland populations since the end of the Messinian salinity crisis (MSC), i.e. since c. 5.5-5.3 Ma, while our divergence time estimates indicate that the isolation of Crete from the mainland populations (Peloponnese, Anatolia) most likely pre-dates the MSC. The observed rates of divergence imply a time window of c. 1.6-1.1 million years for diversification of the largest Anatolian MHG; divergence between the two other Anatolian MHGs may have begun about 3.0 Ma, apparently as a result of uplift of the Amanos Mountains. Our mtDNA data suggest that the Anatolian water frogs and frogs from Cyprus represent several undescribed species.

Genetic diversity in mitochondrial 12S rDNA of western Palearctic water frogs (Anura, Ranidae) and implications for their systematics

The nucleotide sequence of a part of the mitochondrial 12S rRNA gene of eight western Palearctic water frog species was analysed. The results are consistent with the species status of Rana bedriagae, Rana bergeri, Rana epeirotica, Rana lessonae, Rana perezi, Rana ridibunda, Rana saharica and Rana shqiperica. The obtained DNA data suggest that lake frogs from Greece and Yugoslavia on the one hand and lake frogs from Georgia, Uzbekistan and Turkmenistan on the other hand represent two distinct species. However, it is not yet clear whether lake frogs from Georgia, Uzbekistan and Turkmenistan belong to R. ridibunda or represent a new species. The very high similarity between the analysed 12S rDNA segments of German R. ridibunda and R. lessonae confirm the finding that mtDNA of R. lessonae was transmitted into the mitochondrial gene pool of R. ridibunda probably as a result of backcrosses with the hybridogenetic hybrid R. kl. esculenta. The results of parsimony analyses speak in favour of very close phylogenetic relations between R. perezi and R. saharica; with a high probability these species represent an adelphotaxon. Furthermore, the clades (R. lessonae + R. shqiperica + R. bergeri) and (R. ridibunda + R. bedriagae) are considered to be sister groups. According to the mt 12S rDNA data R. epeirotica seems to be more closely related to the supraspecific taxon (R. ridibunda + R. bedriagae) than to (R. lessonae + R. shqiperica + R. bergeri). Thus, it can be excluded that R. shqiperica and R. epeirotica represent sister species.

The water frogs of Greece: Bioacoustic evidence for a new species

The structure of the mating call of lake frogs (referred to as R. ridibunda) from 16 populations in Greece was analyzed for local variation using multivariate statistics. The populations of Thrace and of the island of Samothraki form a group giving the same type of mating call, whereas the mating call of the other populations differs in the degree of temperature dependence of four parameters, and specifically in the number of pulses/pulse group and pulse groups/call. Discriminant functions distinguish even single call series with a probability of 97%, intermediate mating calls are absent, and there is a significant, but slight differentiation of external morphological characters. These results have strong taxonomic implications. We conclude that the lake frogs of Greece comprise two species. The mating call of the lake frogs from Thrace resembles in all parameters that of the Rana ridibunda in the terra typica restricta (Guryev, CIS). Accordingly, the lake frogs of eastern Greece belong to R. ridibunda. The mating call of these lake frogs consists of 20 pulses/pulse group and of 7 pulse groups/call on the average. Most of Greece is inhabited by the second taxon, Rana balcanica sp. n. Its mating call is characterized by 27 pulses/pulse group and 4 pulse groups/call on the average. The two species in Greece do not differ with respect to coloration and size, but several standardized indices vary significantly: body length/digitus primus length; body length/callus internus length; body length/snout-eye distance; body length/tympanum diameter; tibia length/callus internus length; maximal head width/snout-eye distance.

Modelling the range of Syrian spadefoot toad (Pelobates syriacus) with combination of GIS-based approaches

AbstractSyrian spadefoot toads (Pelobates syriacus) are found from Balkan Peninsula throughout the Caucasus, Middle East, and Northern Iran. However, the range of this species is sufficiently mapped only in Balkans. Based on the detailed mapping of the species in Georgia, we analysed the environmental factors influencing species occurrence and produced spatial models for the entire range. Nine models based on the logistic regression, discriminant function analysis, and classification tree analysis, all showed significant influence of the vegetation index and maximum summer temperature on the species distribution. The habitat suitability models based on the presence-only data (Mahalanobis distance estimation and Maximum Entropy approach) had a better performance than the models based on the presence-absence data. The habitat suitability models included two variables only, identified as significant in all preliminary analyses. The area identified as suitable by presence-only models strongly increases when a few environmental variables are included in the analysis. When only two variables are considered, the model predicted large areas north of the actual range. Competition with the related common spadefoot toad (P. fuscus) might have a role on the position of the northern limit of the range of P. syriacus. Within the predicted range, use of breeding sites is negatively associated with presence of fish. Breeding pond preferences of P. syriacus were particularly similar to those of the lake frog (Rana ridibunda), although the latter species uses appropriate habitats more extensively.

New hypotheses on the systematics of the western Palearctic water frog complex (Anura, Ranidae)

During the past 30 years the number of recognized western Palearctic water frog species has increased from just two at the end of the 1960s to at least 14 today. According to new sequence data from mitochondrial genes (12S rRNA. ND3) undescribed species are believed to occur on Cyprus and in central Asia. Furthermore, genetic data suggest that Anatolian lake frogs represent neither Rana bedriagae nor Rana ridibunda but a separate undescribed species. Due to several specific characters species status may also be awarded to lake frogs from south-western Anatolia which have already been described as Rana ridibunda caralitana. The results of various phylogenetic analyses speak in favour of a very close phylogenetic relationship between Rana saharica and Rana perezi. Both species are clearly separated from the other water frog species, which fall into two clades. One clade includes (Rana lessonae + Rana bergeri + Rana shqiperica), the second comprises the lake frog species Rana ridibunda, Rana bedriagae, the Asian lake frog group, the Cypriote water frogs. Rana cretensis, and Rana epeirotica. While the phylogenetic relationships within the “pool frog clade” are considered to be clear (there is strong evidence that Rana lessonae and Rana bergeri represent sister species), the relationships within the “lake frog clade” remain largely unresolved. However, in all phylogenetic trees obtained Rana epeirotica, Rana cretensis, and the Cypriote lineage branched off earlier than R. ridibunda, R. bedriagae and the Asian lake frog group and therefore seem to represent phylogenetically older taxa.

Symbiotic bacteria contribute to innate immune defenses of the threatened mountain yellow-legged frog, Rana muscosa

Symbiotic microorganisms influence health and disease and may contribute to the innate immune defenses of amphibians. The mountain yellow-legged frog, Rana muscosa, is currently undergoing unprecedented population declines. One cause of recent declines is the pathogenic chytrid fungus, Batrachochytrium dendrobatidis ( Bd). Skin swabs for detection of Bd, skin peptide secretions, and symbiotic skin bacteria were collected from 70 adult R. muscosa from two populations designated “Sixty Lake” and “Conness” in 2004–2005. The Conness population has persisted with the presence of Bd for at least 6 years whereas the Sixty Lake population is newly infected and declining. Of the frogs sampled at Conness, 67.5% were infected; whereas 96.7% of the Sixty Lake frogs were infected. Sixty Lake frogs were also more intensely infected than frogs at Conness. We isolated symbiotic bacteria that may contribute to immune defense. A significantly greater proportion of individuals with at least one anti- Bd bacterial species present were found at Conness (85%) than at Sixty Lake (62%). We observed no apparent differences in total skin peptides recovered; however, peptide mixtures from frogs at Sixty Lake showed better growth inhibitory activity against Bd than peptides from frogs at Conness. By MALDI-TOF MS analysis, there were no differences between the two populations in the previously described antimicrobial peptides (ranatuerin-2Ma, ranatuerin-2Mb, and temporin-1M). Antimicrobial skin peptides are only one factor in the resistance of R. muscosa to Bd infection. We suggest that symbiotic bacteria with the ability to persist in the presence of mucosal peptides may inhibit infection and colonization of the skin by Bd and increase the effectiveness of innate defense mechanisms in the skin.

Использование бесхвостых амфибий в системе биомониторинга для оценки влияния отходов предприятий по переработке урановой руды на зооценоз

Дослідження впливу відходів підприємств із переробки уранової руди показали, що єдиний вид земноводних, який мешкає у стічних водах – озерна жаба (Rana ridibunda). Особини старших вікових груп цього виду амфібій частково пристосувалися до впливу полютантів стічних вод за рахунок зміни фізіолого-біохімічних параметрів органів, що беруть активну участь у метаболізмі.

West Nile virus in the vertebrate world

West Nile virus (WNV), an arthropod-borne virus belonging to the family Flaviviridae, had been recognized in Africa, Asia and the south of Europe for many decades. Only recently, it has been associated with an increasing number of outbreaks of encephalitis in humans and equines as well as an increasing number of infections in vertebrates of a wide variety of species. In this article, the data available on the incidence of WNV in vertebrates are reviewed. Moreover, the role of vertebrates in the transmission of WNV, the control of WNV infections in veterinary medicine as well as future perspectives are discussed. A wide variety of vertebrates, including more than 150 bird species and at least 30 other vertebrate species, are susceptible to WNV infection. The outcome of infection depends on the species, the age of the animal, its immune status and the pathogenicity of the WNV isolate. WNV infection of various birds, especially passeriforms, but also of young chickens and domestic geese, results in high-titred viremia that allows arthropod-borne transmission. For other vertebrate species, only lemurs, lake frogs and hamsters develop suitable viremia levels to support arthropod-borne transmission. The role of vertebrates in direct, non-arthropod-borne transmission, such as via virus-contaminated organs, tissues or excretions is less well characterized. Even though direct transmission can occur among vertebrates of several species, data are lacking on the exact amounts of infectious virus needed. Finally, the increased importance of WNV infections has led to the development of killed, live-attenuated, DNA-recombinant and chimeric veterinary vaccines.

The Helminth Fauna of Lake Frog ( Rana ridibunda Pallas, 1771) in Ferghana Valley, Uzbekistan

A survey was conducted on qualitative and quantitative composition of the helminth fauna of the lake frog, Rana ridibunda, in Ferghana Valley, Uzbekistan. Data were collected on the level of infection and its intensity, places and time of findings, index of abundance for 26 helminth species; 10 species of trematodes, 3 species of cestodes, 4 species of acanthocephalans, and 9 species of nematodes. Brief descriptions and drawings are provided for five helminth species first reported from Uzbekistan.

Responses to synthetic advertisement calls by lake frogs from western Anatolia

Bioacoustic and morphological measurements suggest that the lake frog, Rana ridibunda, may represent different species or subspecies over its wide geographic range. Vocal responses from male lake frogs from western Turkey were analyzed in response to laboratory playbacks of synthetic advertisement calls of lake frogs from Turkey, Israel, and Greece. Lake frogs in Israel (Rana bedriagae) and Greece (R. balcanica) are thought to represent different species. Stimuli varied in the number of pulse groups in each call. Males responded most vigorously to playbacks of the R. bedriagae call. In contrast, males rarely responded to the calls of R. balcanica, and never responded to the calls of Hyla cinerea. Males preferred stimuli with more rather than fewer pulse groups. These observations may be used in the classification of Turkish R. ridibunda populations.

The effects of exogenous nitric oxide on the function of neuromuscular synapses.

Extracellular recording experiments using neuromuscular skin/chest muscle preparations from lake frogs were performed at low extracellular Ca2+ ion concentrations to study the effect of L-arginine (the substrate for nitric oxide synthesis) and N(G)-nitro-L-arginine methyl ester (a blocker of NO synthase) on the parameters of evoked transmitter secretion and ion currents in motor nerve endings. L-arginine at a concentration of 100 microM decreased the amplitude of endplate currents as well as their quantum composition, and also increased the amplitude of the third phase of the evoked nerve ending response, which reflects the kinetics of potassium influx currents. N(G)-nitro-L-arginine methyl ester at a condition of 100 microM led to increases in the amplitude and quantum composition of endplate currents and decreased the amplitude of the third phase of the evoked nerve ending response. It is suggested that endogenous nitric oxide is produced in frog neuromuscular synapses, which in normal conditions suppresses transmitter secretion and modulates the function of potassium channels in the nerve ending.