[show abstract][hide abstract] ABSTRACT: A thermotolerant, Gram-positive, aerobic, endospore-forming, acidophilic bacterium (strain Kr1T) was isolated from the pulp of a gold-containing sulfide concentrate processed at 40 degrees C in a gold-recovery plant (Siberia). Cells of strain Kr1(T) were straight to slightly curved rods, 0.8-1.2 microm in diameter and 1.5-4.5 microm in length. Strain Kr1T formed spherical and oval, refractile, subterminally located endospores. The temperature range for growth was 20-60 degrees C, with an optimum at 40 degrees C. The pH range for growth on medium containing ferrous iron was 1.2-2.4, with an optimum at pH 2.0; the pH range for growth on medium containing S0 was 2.0-5.0, with an optimum at pH 2.5. Strain Kr1T was mixotrophic, oxidizing ferrous iron, S0, tetrathionate or sulfide minerals as energy sources in the presence of 0.02 % yeast extract or other organic substrates. The G+C content of the DNA of strain Kr1T was 48.2+/-0.5 mol%. Strain Kr1T showed a low level of DNA-DNA reassociation with the known Sulfobacillus species (11-44 %). 16S rRNA gene sequence analysis revealed that Kr1T formed a separate phylogenetic group with a high degree of similarity between the nucleotide sequences (98.3-99.6 %) and 100 % bootstrap support within the phylogenetic Sulfobacillus cluster. On the basis of its physiological properties and the results of phylogenetic analyses, strain Kr1T can be affiliated to a novel species of the genus Sulfobacillus, for which the name Sulfobacillus thermotolerans sp. nov. is proposed. The type strain is Kr1T (=VKM B-2339T=DSM 17362T).
International journal of systematic and evolutionary microbiology 06/2006; 56(Pt 5):1039-42. · 2.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Electron microscopy examinations of thin sections and freeze-fracture replicas revealed the specific ultrastructural features of Alicyclobacillus tolerans strain K1(T). In particular, the cell wall displayed an ultrastructure typical of gram-positive bacteria and consisted of a thin murein layer (50-60 A in thickness); cells exhibited a surface S-layer constituted by large hexagonally packed (p6-symmetry) rod-shaped subunits of 150-160 A in diameter and 200 A in height. In the cytoplasmic membrane, there were intramembrane vesicular structures that sometimes appeared as large leaflets in the central part. The cytoplasm contained numerous vesicular inclusions covered with a monolayered wall, dissimilar to bilamellar lipid membranes. Endospore coats displayed an intricate structure and consisted of three thick layers; the outer layer had an unusual fine structure; the exosporium was also found.
Archives of Microbiology 04/2006; 185(1):63-8. · 1.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: The method of X-ray microanalysis was used for the detection of microbial cells among cell-like particles immediately in the samples of 170 thousand year old ancient Antarctic permafrost sediments. The X-ray spectra and the quantitative parameters of P, S, Ca and K contents in cell-like particles, as well as ratios Ca/K and P/S, were compared with the corresponding data obtained for microbial cells of various physiological states: vegetative cells -- resting forms -- non-viable micromummies. The absence of P and S peaks in X-ray spectra in the most of cell-like particles allowed us to regard them as non-living objects. Among other investigated cell-like particles we were able to find the resting forms of microorganisms with the increased intracellular level of Ca, high Ca/K ratio and low P/S ratio. So, X-ray microanalysis is a promising tool for a primary detection of microbial cells in situ and determination of their physiological state.
[show abstract][hide abstract] ABSTRACT: Non-spore-forming bacteria of the genera Micrococcus and Arthrobacter, including the isolates from permafrost sediments, were found to be able to form cystlike cells under special conditions. Cystlike cells maintained the viability during long-term storage (for up to several years), had undetectable respiratory activity and the elevated resistance to heating and other unfavorable conditions, possessed the specific fine structure and morphology, and were formed in the life cycles of the microorganism. These properties allow cystlike cells to be attributed to a new type of resting microbial forms. Furthermore, the distinctive feature of resting cystlike cells was their low P/S ratios and high Ca/K ratios in comparison to vegetative cells as shown by X-ray microanalysis. The experimentally obtained bacterial cystlike cells with thickened and laminated cell walls and altered texture of the cytoplasm were similar to the cells abundant in native microbial populations isolated from permafrost sediments and ancient soils of the Kolyma lowland (Siberia, Russia). Due to the inherent elevated resistance to adverse conditions and maintenance of viability for prolonged periods, resting cystlike cells are likely to ensure long-term survival of non-spore-forming bacteria in cold environments.
[show abstract][hide abstract] ABSTRACT: The source of carbon of Early Archean graphites of Nimnyr suite of Aldan shield was cyanobacterial mat. In the region of its development there existed eucariots of diatoms type. It confirms the earlier supposition that eucariots were as ancient gropu of microorganisms as procariots. A well developed microbiota Early Archean means that there was no time for biopoese, forming cells and further evolution of organisms on Earth and consequently there was a possibility of bringing life to the Earth from Solar objects by representatives of all the three lines of microorganisms - arphea, bacteria and eucariots. The ability of bacterial organisms to form mineral-organic cocoons in transition to anabiotic state under conditions of permafrost as well as the ability of microorganisms remnants to preserve their biochemical peculiarities and cell structure that could be revived during long periods of geological age makes this possibility even more real. The evidence of microorganisms in ancient graphites enables us to refer these highcarbon formations to the rank of prospective objects for cognition of biological diversity of the Earth biosphere at the initial stages of its development.
[show abstract][hide abstract] ABSTRACT: For the last few years there have been a lot of publications in geological literature on the problem of formation of morphologically unique fine fibrous kerites, found in one of the objects of kamera pegmatites of Volyn (1800 - 1750 mln. years). According to the opinion of all researchers who deal with them, they are an excellent example of a biogenic, highly constructive carbon substance. The meeting of objectives set was carried out by means of the study of ultra-thin section and replicas of kerite cryofractures under high resolution electronic microscope. The similarity of fine structured fibrous kerite of Volyn (KV) to prokaryotic microorganisms is proved by availability in KV of clearly exposed cellular ultrastructures: multilayered cell wall, cross septa and cytoplasmatic membrane and `intracytoplasmic' inclusions. Fatty acids obtained from kerites contain a number of components typical of prokaryotic microbial community. Suggestions were made on the formation of fibrous Volyn's kerites as a result of mummification of the cyanobacterial mat components from freshwater thermal spring of moderate temperature. Thus, the detailed fine structure of microfossils and their fatty acid composition can be used to support evidence of biogenic origin of the bacteriomorphic elements in paleo- and space objects.