Thermoanaerobium lactoethylicum spec. nov. a new anaerobic bacterium from a hot spring of Kamchatka

A new anaerobic thermophilic Gram-positive, nonsporeforming bacterium strain ZE-1 was isolated from a hot spring of Kamchatka (USSR). The cells are rod-shaped, (0.5–0.8 · 2.0–20 m), non-motile. The bacterium can grow between 42 and 75°C; the optimal temperature is 65°C. The growth is possible between pH values 5.0 and 8.5; optimal pH is 7.0. The cultures grow on the media containing peptone, yeast extract, or casein hydrolysate as nitrogen sources in the presence of glucose or some other sugars, mannitol or starch. The main fermentation products of glucose are ethanol, acetate, lactate, H₂, CO₂; byproducts are propionic, butyric and isovaleric acids. Glucose is metabolized via Embden-Meyerhoff-Parnas pathway. Molecular hydrogen does not inhibit growth. The bacterium does not reduce aceton to isopropanol, but is able to form H₂S from elemental sulfur. The bacterium contains a soluble hydrogenase. This enzyme catalyzes both evolution and uptake of H₂ and is active in the presence of methyl viologen. The DNA-base composition is 34.6 mol%; the genome size 2.08x10⁹ D. The name proposed for the isolated bacterium strain ZE-1 is Thermoanaerobium lactoethylicum spec. nov.     

Production of Recombinant Endostatin in Milk of Transgenic Mice

Using the bovine S1-casein gene, a genetic construct with an endostatin-coding fragment of the mouse collagen XVIII cDNA was designed to express endostatin in milk of transgenic animals. Several transgenic mice were obtained. The mice secreted endostatin in milk at 70–300 ng/l and transmitted this character to their progeny.     

Diversity, activity, and abundance of sulfate-reducing bacteria in saline and hypersaline soda lakes

Soda lakes are naturally occurring highly alkaline and saline environments. Although the sulfur cycle is one of the most active element cycles in these lakes, little is known about the sulfate-reducing bacteria (SRB). In this study we investigated the diversity, activity, and abundance of SRB in sediment samples and enrichment cultures from a range of (hyper)saline soda lakes of the Kulunda Steppe in southeastern Siberia in Russia. For this purpose, a polyphasic approach was used, including denaturing gradient gel electrophoresis of dsr gene fragments, sulfate reduction rate measurements, serial dilutions, and quantitative real-time PCR (qPCR). Comparative sequence analysis revealed the presence of several novel clusters of SRB, mostly affiliated with members of the order Desulfovibrionales and family Desulfobacteraceae. We detected sulfate reducers and observed substantial sulfate reducing rates (between 12 and 423 micromol/dm(3) day(-1)) for most lakes, even at a salinity of 475 g/liter. Enrichments were obtained at salt saturating conditions (4 M Na(+)), using H(2) or volatile fatty acids as electron donors, and an extremely halophilic SRB, strain ASO3-1, was isolated. Furthermore, a high dsr gene copy number of 10(8) cells per ml was detected in a hypersaline lake by qPCR. Our results indicate the presence of diverse and active SRB communities in these extreme ecosystems.     

Studies on cellular immunity toSalmonella typhi in vitro

Salmonella typhi (strain Ty2—4446) cultivatedin vitro within the macrophage of mice immunised twice specifically with a high dose of killed vaccine, multiplied less intensively than in the cells of non-immunised control animals during 24 hours cultivation. In addition, a certain suppression of growth ofSalmonella enteritidis andSalmonella suis var. Kunzendorf was observed in the macrophages of mice immunised withSalmonella typhi vaccine. Double immunisation of mice with high doses of killed vaccine fromSalmonella enteritidis andSalmonella suis led to the mice macrophages being able to suppress multiplication of both homologous microbes andSalmonella typhi. The formation of such cross resistance in mice immunised with salmonella vaccines excludes the possible participation of O, H, and Vi antibodies in this phenomenon.     

Bacterial diversity and activity along a salinity gradient in soda lakes of the Kulunda Steppe (Altai, Russia)

Here we describe the diversity and activity of sulfate reducing bacteria along a salinity gradient in four different soda lakes from the Kulunda Steppe (South East Siberia, Russia). For this purpose, a combination of culture-dependent and independent techniques was applied. The general bacterial and SRB diversity were analyzed by denaturing gradient gel electrophoresis (DGGE) targeting the 16S rDNA gene. DNA was used to detect the microbial populations that were present in the soda lake sediments, whereas ribosomal RNA was used as a template to obtain information on those that were active. Individual DGGE bands were sequenced and a phylogenetic analysis was performed. In addition, the overall activity of SRB was obtained by measuring the sulfate reduction rates (SRR) and their abundance was estimated by serial dilution. Our results showed the presence of minor, but highly active microbial populations, mostly represented by members of the Proteobacteria. Remarkably high SRR were measured at hypersaline conditions (200 g L⁻¹). A relatively high viable count indicated that sulfate reducing bacteria could be highly active in hypersaline soda lakes. Furthermore, the increase of sodium carbonate/bicarbonate seemed to affect the composition of the microbial community in soda lakes, but not the rate of sulfate reduction.     

Thermohydrogenium kirishiense gen. nov. and sp. nov., a new anaerobic thermophilic bacterium

Six strains of a new anaerobic thermophilic non-sporeforming bacterium were isolated in pure culture from industrial yeast biomass. Cells were rod-shaped (0.4–0.8×1.0–11.0 m), non-motile. They stained gram-negative, but outer membrane was not present. The growth occurred between 45–75 °C, the optimal temperature is 65°. Optimal pH value was 7.0–7.4. The bacterium utilized for growth several sugars, starch and yeast extract. The best source of nitrogen was peptone. The main fermentation products of glucose were ethanol, acetate, H₂ and CO₂. As minor products isopropanol, butanol, butyrate and lactate were found. Glucose was metabolized via the Embden-Meyerhoff pathway. Cytochromes and quinones were not found. DNA-base composition was 33.2–34.0 mol%. The DNA-DNA hybridization and 5S rRNA nucleotide sequences showed distantly related of isolated stains to phenotypical similar bacteria. It was proposed to consider the isolated bacterium as Thermohydrogenium kirishiense gen. nov. and sp. nov.     

Changes of calcium binding protein expression in spinothalamic tract neurons after peripheral inflammation

Specific neuronal populations are known to express calcium binding proteins (CBP) such as calbindin (CB), parvalbumin (PV) and calretinin (CR). These CBP can act as calcium buffers that modify spatiotemporal characteristics of intracellular calcium transients and affect calcium homeostasis in neurons. It was recently shown that changes in neuronal CBP expression can have significant modulatory effect on synaptic transmission. Spinothalamic tract (STT) neurons form a major nociceptive pathway and they become sensitized after peripheral inflammation. In our experiments, expression of CBP in STT neurons was studied in a model of unilateral acute knee joint arthritis in rats. Altogether 377, 374 and 358 STT neurons in the segments L3-4 were evaluated for the presence of CB, PV and CR. On the contralateral (control) side 1%, 9% and 47% of the retrogradely labeled STT neurons expressed CB, PV and CR, respectively. On the ipsilateral (arthritic) side there was significantly more CB (23%) and PV (25%) expressing STT neurons, while the number of CR positive neurons (50%) did not differ. Our results show increased expression of fast (CB) and slow (PV) calcium binding proteins in STT neurons after induction of experimental arthritis. This suggests that change in CBP expression could have a significant effect on calcium homeostasis and possibly modulation of synaptic activity in STT neurons.     

Sulfidogenesis in hypersaline chloride-sulfate lakes of Kulunda Steppe (Altai, Russia)

The activity and culturable diversity of sulfidogens were investigated in anoxic sediments of four hypersaline lakes with pH 7.6-8.2 in the Kulunda Steppe (Altai, Russia). Sulfate reduction rates were low, varying from 0.1 to 6.0 nmol HS(-) /(cm(3) h) with a maximum in the top 10 cm layer. Potential sulfidogenic rates with thiosulfate and sulfur as the e-acceptors were higher than with sulfate and were stimulated by formate, lactate, and acetate. Sulfidogenesis was optimal at salt concentrations below 2 M NaCl. Cultivation at 2 M NaCl resulted in the isolation of several strains of moderately halophilic SRB, but no growth of SRB was observed at 4 M NaCl. At lithotrophic conditions (i.e., with formate or H(2) as e-donors), several closely related alkalitolerant strains belonging to the genus Desulfonatronovibrio were isolated. Enrichments at heterotrophic conditions with lactate, propionate, acetate, or butyrate using sulfate or thiosulfate as e-acceptors yielded isolates related to Desulfosalsimonas propionicica, Desulfohalobium utahense, and Desulfocella halophila. Sulfur-reducing enrichments at 2 M NaCl with ethanol produced a member of the genus Halanaerobium, while enrichments at 4 M NaCl with acetate were dominated by archaea, demonstrating for the first time such type of catabolism in haloarchaea.     

Nucleosome positioning on yeast plasmids is determined only by the internal signal of DNA sequence occupied by the nucleosome

The possible role of border factors in determining the nucleosome positioning on a DNA sequence was investigated. To this end a family of recombinant plasmids based on Gal10Cyc1 promoter and neomycin phosphotransferase gene NPTII were created. A DNA sequence adjoining the GalCyc promoter was varied in these plasmids. Three nearly equally represented nucleosome positions on the GalCyc promoter were found. In the basal plasmid an FRT sequence adjoins the GalCyc promoter at the right. It contains an internal signal of multiple positioning. Its replacement with different DNA sequences does not affect nucleosome positioning on the GalCyc promoter. The nucleosome positioning on the GalCyc promoter does not depend on nucleosome positioning (or its absence) on adjoining sequences. The same is true for nucleosome positioning on FRT sequence. It was found also that nucleosomes' positioning on the NPTII gene and their mutual disposition, namely the spacing between neighboring nucleosomes (linker length) are determined by the location of positioning signals only. Generally the nucleosome positioning in our experimental model is determined solely by internal DNA sequence occupied by nucleosome. On the other hand, the action of this internal positioning signal does not extend to neighboring DNA sequences.