A novel nematode species from the Siberian permafrost shares adaptive mechanisms for cryptobiotic survival with C. elegans dauer larva.

Some organisms in nature have developed the ability to enter a state of suspended metabolism called cryptobiosis when environmental conditions are unfavorable. This state-transition requires execution of a combination of genetic and biochemical pathways that enable the organism to survive for prolonged periods. Recently, nematode individuals have been reanimated from Siberian permafrost after remaining in cryptobiosis.

Viable Nematodes from Late Pleistocene Permafrost of the Kolyma River Lowland.

We have obtained the first data demonstrating the capability of multicellular organisms for longterm cryobiosis in permafrost deposits of the Arctic. The viable soil nematodes Panagrolaimus aff. detritophagus (Rhabditida) and Plectus aff.

Morphology and phylogeny of the testate amoebae Euglypha bryophila Brown, 1911 and Euglypha cristata Leidy, 1874 (Rhizaria, Euglyphida).

The genus Euglypha contains the largest number of filose testate amoeba taxa which were mainly described based on the morphological characteristics of shells. Despite the increasing amount of molecular data, the phylogenetic relationships within the genus Euglypha remain unresolved. In this work we provide new data on SSU rRNA gene sequences, light and electron microscopy for the two euglyphid species Euglypha bryophilaBrown, 1911 and Euglypha cristataLeidy, 1874.

Ciliates from ancient permafrost: Assessment of cold resistance of the resting cysts.

There is evidence that resting cysts of soil ciliates and numerous taxa of other protists can survive in permafrost for thousands of years at subzero temperatures; however, our knowledge about mechanisms of long term cryobiosis remains incomplete. In order to better understand the means by which ancient cysts survive, we investigated resistance to cyclical supercooling stress of resting cysts of the soil ciliate Colpoda steinii (Colpodida, Ciliophora). Three clonal strains were used for comparison, isolated from Siberian tundra soil, ancient Holocene (5-7,000 y) and late Pleistocene (32-35,000 y) permafrost sediments.

Cryptic diversity within the choanoflagellate morphospecies complex Codosiga botrytis - phylogeny and morphology of ancient and modern isolates.

Choanoflagellates are closely related to metazoans and fungi according to recent phylogenetic studies; therefore the systematics of these organisms is of particular interest. The choanoflagellate morphospecies Codosiga botrytis is the first described choanoflagellate, and is one of the most frequently reported choanoflagellate species. In this study we present phylogenetic and morphological data on eight different strains of Codosiga botrytis.

Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology.

Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one.

[Spectral properties of the green alga Trebouxia--a phycobiont of cryptoendolithic lichens in the high-latitude polar regions of Antarctica].

An algologically pure culture of the green alga Trebouxia, a phycobiont of cryptoendolithic lichens, was isolated from the sandstone samples collected in the high-altitude polar regions of Antarctica. The absorption and the second-derivative absorption spectra of the acetone extract of the Antarctic phycobiont cells were studied in comparison with those of the Trebouxia phycobiont isolated recently from the Parmeliaceae lichen in the Mid-European climatic zone. The cells of the Antarctic phycobiont were characterized by a lower content of chlorophyll a and a higher ratio of chlorophyll b and carotenoids to chlorophyll a as compared to the Mid-European phycobiont.

[The possible contribution of late pleistocene biota to biodiversity in present permafrost zone].

During the last decade a wide range of biological objects, which have preserved their viability for tens and hundreds of thousands of years, was found in the samples of permafrost sediments from North-East Eurasia. Among them are bacteria, fungi, algae, moss spores, seeds of higher plants, protists. Along with physiological mechanisms of cryoconservation and constant low temperature of great importance for long-term preservation of biological objects in permafrost layers are ways of burying the organisms and conditions that prevail before the transition of sediments to the permafrost state.

[The absorption and fluorescence spectra of the cyanobacterial phycobilins of cryptoendolithic lichens in the high-polar region of Antarctica].

The algologically pure cultures of the green-brown cyanobacterium Chroococcidiopsis sp. and three cyanobacteria of the genus Gloeocapsa, the blue-green Gloeocapsa sp.1, the brown Gloeocapsa sp.