Greenhouse gas emission in West Siberia

The major gases contributing to the greenhouse effect are carbon dioxide and methane (60 and 15–18%, respectively). The former Soviet Union area accounts for 11% of the global methane flux on the average. However, virtually no records of methane flux were kept in Russia in the late 1980s-early 1990s. Inventories of methane emission in Russia were reported in the middle 1990s, but those data were confined to measurements performed by the early 1990s. This paper presents generalized data on methane and carbon dioxide emission from the surfaces of marsh ecosystems in West Siberia in the 1990s, when the majority of measurements were carried out.     

Optimization of mycophenolic acid production in solid state fermentation using response surface methodology

Mycophenolic acid (MPA) can be produced in solid state fermentation. An isolate of Penicillium brevi-compactum ATCC 16024 grown on moist wheat bran produced a titre of 425 mg per kg of wheat bran. Central composite rotatable design and response surface methodology were employed to derive a statistical model for media optimization towards production of mycophenolic acid. Five levels with a five factorial design were adopted. The correlation coefficient was 0.82, ensuring a satisfactory adjustment of the model to the experimental values. This statistical design was very effective in improving the titre of mycophenolic acid up to 3286 mg per kg of wheat bran. Received 24 July 1998/ Accepted in revised form 4 December 1998     

Methane oxidation in landfill cover soil

Methane oxidation in the cover soil of the Khmet'evo municipal landfill in Moscow oblast was investigated. Methane emission from the experimental parcel of the site was highly inhomogeneous. At a depth of 45-60 cm, the pore gas mainly consisted of CH4 (60-70%) and CO2 (30-40%). In the upper horizons of the cover soil, the concentration of these gases sharply decreased. Techniques for estimation of the methane-oxidizing activity in the cover soil of the landfill were tested. The rate of methane oxidation in the soil, the factor limiting methane emission from the surface of the site, correlated with the cell number of culturable methanotrophic bacteria. The method of indirect immunofluorescence revealed ten known species of methanotrophic bacteria in enrichment cultures obtained from samples of the cover soil. Our results also indicate the presence of unknown psychrotolerant methanotrophs that are active at the low temperatures characteristic of Moscow oblast.     

Emission analysis of RE3+ (RE = Sm,Dy):B2O3‐TeO2‐Li2O‐AlF3 glasses

This article reports on the optical properties of 0.5% mol of Sm³⁺, Dy³⁺ ion‐doped B₂O₃‐TeO₂‐Li₂O‐AlF₃ (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd‐Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm³⁺ and Dy³⁺:LiAlFBT glasses showed a bright reddish‐orange emission at 598 nm (⁴G_5/2 → ⁶H_7/2) and an intense yellow emission at 574 nm (⁴F_9/2 → ⁶H_13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm³⁺ and Dy³⁺:LiAlFBT glasses. Copyright © 2012 John Wiley & Sons, Ltd.     

Electrochemical gradient of H+ ions as an immediate source of energy during bacteria movement]

An uncoupler of oxidative phosphorylation causes an instantaneous cessation of movement of bacteria Rhodospirillum rubrum in the presence and in the absence of oligomycin. It is concluded that such cessation is not due to a decrease in the ATP concentration but to the elimination of deltamicron-H+ by the uncoupler. The mobility of the bacteria does not practically change in the presence of acetate and is, to some extent, decreased after addition of valinomycin or penetrating cation of tetraphenyl phosphonium. Under a combined action of acetate and valinomycin the movement is depleted. It is concluded that both constituents of deltamicronH+-transmembrane difference of electric potentials and the pH gradient--may serve as energy sources for the bacteria movement. Inhibitory analysis data suggest that the bacteria movement may be maintained by any of the deltamicronH+ sources, e.g. light-dependent cyclic electron transfer, respiration, ATPase and membrane pyrophosphatase.     

Redox-sensing is the basis of photophobic responses in cyanobacteria

Abstract Cyanobacteria lack specialized photoreceptors for photophobic responses (PPR), the action spectrum for photosynthesis coinciding with that for PPR. In the presence of 3-(3',4'-dichlorophenyl)-1,1-dimethyl urea) (DCMU), which blocks electron transfer prior to plastoquinone (PQ), turning on the light increased the membrane potential, but simultaneously evoked an unusual phobic response, presumably due to oxidation of PQ · H₂ via photosystem I (PS I). White light and the PQ reductant, (DQ · H₂), acted as attractants and produced methylation of a 40 kDa membrane peptide. Repellents, an uncoupler, carbonyl cyanide m -chlorophenylhydrazone (CCCP), and an oxidant, tetramethyl- p -hydroquinone(duroquinon) (DQ), caused demethylation. The results are interpreted in the framework of Häder's 'electron pool hypothesis', according to which PQ · H₂ level governs PPR. It is further concluded that the same system is the mechanism of pmf-sensing:      

Involvement of Ca2+ and cGMP in bacterial taxis

Abstract The level of cGMP in a suspension of Escherichia coli cells increased transiently upon the addition of chemoattractants. Ca²⁺ (1 mM), but not Mg²⁺, produced constant tumbling of cells in the presence of the ionophore A23187. The effect was observed either in stationary-state cells, or in a logarithmic culture treated with EDTA to increase permeability by A23187. Under the same conditions, Ca²⁺ decreased the cytoplasmic level of cGMP. In Phormidium uncinatum , rapid ⁴⁵Ca²⁺ accumulation followed a light-dark stimulus, or the addition of tetramethylquinone (TMQ), a chemorepellent. La³⁺, which increases the reversal rate, also enhanced the level of cytoplasmic Ca²⁺, presumably by blocking the outward Ca²⁺ flux. In both E. coli and P. uncinatum Ca²⁺ inhibited methylaccepting chemotaxis protein (MCP) methylation. It is concluded that cGMP and Ca²⁺ are secondary messengers in taxis information-processing.