De novo assembly and analysis of the transcriptome of the Siberian wood frog Rana amurensis.

The Siberian wood frog Rana amurensis Boulenger, 1886 is the most hypoxia-tolerant amphibian. It can survive for several months in an almost complete absence of oxygen. Little is known about the mechanisms of this remarkable resilience, in part because studies of amphibian genomes are impeded by their large size. To make the Siberian wood frog more amenable for genetic analysis, we performed transcriptome sequencing and de novo assembly for the R. amurensis brain under hypoxia and normoxia, as well as for the normoxic heart. In order to build a de novo transcriptome assembly of R. amurensis, we utilized 125-bp paired-end reads obtained from the brain under normoxia and hypoxia conditions, and from the heart under normoxia. In the transcriptome assembled from about 100,000,000 reads, 81.5 % of transcripts were annotated as complete, 5.3 % as fragmented, and 13.2 % as missing. We detected 59,078 known transcripts that clustered into 22,251 genes; 11,482 of them were assigned to specific GO categories. Among them, we found 6696 genes involved in protein binding, 3531 genes involved in catalytic activity, and 576 genes associated with transporter activity. A search for genes encoding receptors of the most important neurotransmitters, which may participate in the response to hypoxia, resulted in a set of expressed receptors of dopamine, serotonin, GABA, glutamate, acetylcholine, and norepinephrine. Unexpectedly, no transcripts for histamine receptors were found. The data obtained in this study create a valuable resource for studying the mechanisms of hypoxia tolerance in the Siberian wood frog, as well as for amphibian studies in general.

Cold Resistance of An Ant Camponotus herculeanus (Hymenoptera, Formicidae) in Various Climates in North-East Asia.

　　BACKGROUND: The relationship between cold resistance of widespread invertebrate species and overwintering temperatures has not been studied; however, this knowledge could have high prognostic value. OBJECTIVE: Using an ant species Camponotus herculeanus to investigate whether there is a relationship between cold resistance and overwintering temperatures in two climatically distinct regions (coastal and continental). MATERIALS AND METHODS: We determined seasonal changes in SCP and LТ for overwintering ant stages, as well as winter temperatures in the nests. RESULTS: In the watershed of Upper Kolyma River (Aborigen field station), minimal temperature in the nests dropped to -26С. Average SCP of the ants was -40С, and LТ was -37С. At the coast of the Sea of Okhotsk (Magadan) the minimum in the nest was -14С, SCP was -19C to -27С and LТ was -32С. CONCLUSION: We have established a relationship between cold tolerance and overwintering conditions for geographically separate populations in the two areas with different climatic regimes.

Extreme negative temperatures and body mass loss in the Siberian salamander (Salamandrella keyserlingii, amphibia, hynobiidae).

Frozen Siberian salamander safely tolerates long (45 days) stay at-35°C. Short-term (3 days) cooling down to-50°C was tolerable for 40% of adult individuals; down to-55°C, for 80% of the underyearlings. Generally, the salamanders lose about 28% of the body mass during the pre-hibernating period (before winter, at temperatures as low as 0°C) and during the process of freezing (as low as-5°C). The body weight remained constant upon further cooling (to-35°C). The frozen salamanders have no physiological mechanisms protecting from sublimation.

The Japanese tree frog (Hyla japonica), one of the most cold-resistant species of amphibians.

The Japanese tree frog, a representative of the Manchurian fauna, is characterized by an outstanding cold resistance among the anuran amphibian species studied so far. Almost 70% of the specimens from the population inhabiting the middle Amur River withstand the cooling down to-30°C; some animals, down to-35°C. This exceeds more than twofold the cold hardiness of the wood frog (Lithobates sylvaticus LeConte, 1825), which has been considered earlier to be the most cold-resistant species. The ability of H. japonica to survive for four months in the frozen state at low temperatures makes this species independent of the temperature overwintering conditions.

COLD HARDINESS AND RANGE OF THE MYRIAPOD Angarozonium amurense (POLYZONIIDAE, DIPLOPODA, ARTHROPODA) IN PERMAFROST ENVIRONMENTS.

BACKGROUND: Angarozonium amurense (Gerstfeldt, 1859) is the only one out of more than a hundred diplopod species described in Siberia and the Far East that inhabits regions with solid permafrost. OBJECTIVE: To evaluate the cold hardiness of A. amurense that allows this species to inhabit permafrost regions. METHODS: The survival temperature thresholds and supercooling points (SCP) were measured. RESULTS: The temperature thresholds for adult animal survival are -8.5 C in summer and -27 C in winter. Average SCP decreases from -7.7 in summer to -16.9 in winter. Water content decreases from 55.7% in summer to 49.4% in winter. CONCLUSION: The cold hardiness of A. amurense sets the record in this class of animals. It allows it to overwinter in the upper 15 centimeters layer of soil in most biotopes of the coldest permafrost regions in North Asia.

[Genetic structure of populations of Schrenck newt (Salamandrella schrenckii) based on mitochondrial DNA cytochrome b variability data].

Data on variability of nucleotide sequences of mitochondrial DNA (mtDNA) cytochrome b gene of Schrenck newt, Salamandrella schrenckii (Strauch, 1870), from populations of Primorie and Khabarovsk regions have been received. By means of phylogenetic analysis, two clusters of haplotypes--'southern' cluster 1 and 'northern' cluster 2, with divegence level between them estimated as 3%-- were revealed. Results of analysis of mtDNA and cytochrome b amino acid variation allow us to assume that development of a modern area of Schrenck newt occurred from the south on the north of Primorie region. It was found that 'northern'cluster in contrast to the 'southern' one demonstrates all signs of demographic expansion (i.e., unimodal type of pairwise nucleotide differences, results of tests of selective neutrality of mtDNA variation and good correspondence of genetic parameters to expectations following from the models of demographic expansions).