Study of reservoir properties of carbonate rocks based on analysis of reservoir quality index

The article presents the reservoir properties of carbonate rocks by analyzing the factors that characterize the filtration cell reservoir rocks: reservoir quality index, free fluid index, flow zone indicator. These factors are usually used for clastic reservoirs in order to isolate the flow units - rock volume has certain geological and petrophysical properties, as well as a unified hydraulics. It was believed that such a definition for the carbonate rocks is problematic. However, studies have shown the possibility of allocating the flow units in the carbonate deposits subject to the provision of good reservoir rocks and determination of litho-genetic type of carbonate rocks. For the analysis considered several litho-genetic types. It was found that the best collectors are limestone bioclastic-zoogene type. The coefficients revealed the Flow Units in all productive carbonate deposits considered deposits. Allocation of volumes of rocks possessing common hydraulics allows more correctly carry out operational activities

Aerobic degradation of 2,4,6-trinitrotoluene by the yeast strain Geotrichum candidum AN-Z4

The yeast strain Geotrichum candidum AN-Z4 isolated from an anthropogenically polluted site was able to transform 2,4,6-trinitrotoluene (TNT) via the formation of unstable intermediate hydride Meisenheimer complexes with their subsequent destruction and accumulation of nitrite and nitrate ions as the end mineral forms of nitrogen. Aeration of the medium promoted more profound destruction of this xenobiotic by the strain G. candidum AN-Z4 than static conditions. The yeast strain was shown to produce citrate, succinate, and isocitrate, which sharply acidified the medium and influenced the TNT destruction. Two possible pathways of TNT biodegradation were confirmed experimentally: (1) via the destruction of the TNT-monohydride complex (3-H--TNT) and (2) via the destruction of one protonated TNT-dihydride complex (3,5-2H--TNT · H+). The strain G. candidum AN-Z4, due to its ability for TNT degradation, may be promising for bioremediation of TNT-contaminated soil and water. © Pleiades Publishing, Ltd., 2010

Hydride-mediated reduction of 2,4,6-trinitrotoluene by yeasts as the way to its deep degradation

Broad screening of microorganisms from natural and anthropogenic ecological niches has revealed strains Candida sp. AN-L15 and Geotrichum sp. AN-Z4 which transform, 2,4,6-trinitrotoluene (TNT) via alternative pathways (with the domination of hydride ion-mediated reduction of the aromatic ring) and produce relatively high amounts of nitrites. According to the spectrophotometry data, the hydride attack of TNT by Candida sp. AN-L15 and Geotrichum sp. AN-Z4 grown at pH 5.0-8.0 leads to the mono-and dihydride complexes of TNT (H --TNT and 2H--TNT, respectively) and to protonated forms of the latter. Analysis by HPLC, GC-mass spectrometry, and ion chromatography revealed the products of deep conversion of TNT. The growth of the yeast strains in a weakly acidic medium with TNT (440 μM) is accompanied by formation of 2,4-dinitrotoluene (2,4-DNT, up to 18.2 μM). Together with accumulation of nitrites (up to 76.0 μM, depending on pH of the medium), these findings demonstrate the capacity of both strains for TNT denitration. Formation of 2,4-DNT reflects the realization of one of the possible mechanisms of TNT ortho-nitro group elimination and switching over to the pathways of metabolism of dinitrotoluenes, which are much more easily biodegradable than TNT. Simultaneously with the dominating TNT hydride attack, the mechanism of 4-and 6-electron reduction of the nitro group also functions in Candida sp. AN-L15 and Geotrichum sp. AN-Z4. Realization of the studied mechanisms of TNT transformation under growth of Candida sp. AN-L15 on n-alkane is important for bioremediation in the cases of combined pollution by oil products and explosives. © 2007 Pleiades Publishing, Ltd

Comparative Analysis of Bacterial Communities Associated with Healthy and Inflamed Peri-implant Tissues

© 2016, Springer Science+Business Media New York.Dental implants are used to restore dentition defects. However, despite the high efficiency of the method of placing dental implants, their integration can be accompanied by peri-implant diseases (peri-implant mucositis and peri-implantitis), which are inflammatory reactions induced by the bacterial activity. In the present pilot study, we described and compared the bacterial communities associated with healthy and inflamed peri-implant mucosal tissues using 16S rRNA gene amplicon pyrosequencing approach. It was revealed that various representatives of the phyla Firmicutes, Bacteroidetes, Fusobacteria, and Proteobacteria were found at significant levels in healthy and peri-implant mucositis sites but in different proportions. Furthermore, it was shown that the genus Fusobacterium was the only group present in higher proportions on inflamed tissues than on healthy tissues surrounding dental implants of all patients. In addition, unclassified Methylobacteriaceae and the genus Veillonella as well as some other phylotypes were present at higher levels in peri-implant mucositis sites of some patients. This study indicates that several microbial agents may play important roles during the development of oral peri-implant diseases

Participation of oxygen in the bacterial transformation of 2,4,6-trinitrotoluene

The exposure of Bacillus cereus ZS18 cell suspensions to 2,4,6-trinitrotoluene (TNT) in the absence of other oxidizable substrates increases oxygen uptake, exceeding the basal level of respiration of the bacterium 1.5- and 2-fold with 50 and 100 mg/liter of TNT, respectively. The interaction of both living and to less extent dead bacterial cells with TNT results in the accumulation of superoxide anion ( O2-̇) in the extracellular medium, which was revealed by the EPR spectroscopy. The accumulation of O2̇ decreased by 50-70% in the presence of Cu,Zn-superoxide dismutase of animal origin. In the presence of living bacterial cells, the level of TNT decreased progressively, yielding hydroxylaminodinitrotoluenes together with O2̇. In the presence of heat-killed cells, a moderate decrease in TNT was observed, and the appearance of O2̇ was not accompanied by the production of any detectable TNT metabolites. Chelating agents inhibited the transformation of TNT and decreased the formation of O2̇. The demonstrated generation of O2̇ during the interaction of TNT with K4[Fe(CN) 6] together with the observed effects of chelating agents suggest the participation of iron in the one-electron reduction of TNT and the functioning of an extracellular redox cycle with the involvement of molecular oxygen. © 2008 MAIK Nauka

Microbial community diversity in anaerobic reactors digesting turkey, chicken, and swine wastes

© 2014 by The Korean Society for Microbiology and Biotechnology. The microbial community structures of two continuous stirred tank reactors digesting turkey manure with pine wood shavings as well as chicken and swine manure were investigated. The reactor fed with chicken/swine wastes displayed the highest organic acids concentration (up to 15.2 g/l) and ammonia concentration (up to 3.7 g/l ammonium nitrogen) and generated a higher biogas yield (up to 366 ml/gVS) compared with the reactor supplied with turkey wastes (1.5– 1.8 g/l of organic acids and 1.6–1.7 g/l of ammonium levels; biogas yield was up to 195 ml/gVS). The microbial community diversity was assessed using both sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Additionally, methanogens were analyzed using methyl coenzyme M reductase alpha subunit (mcrA) genes. The bacterial community was dominated by members of unclassified Clostridiales with the prevalence of specific clostridial phylotypes in each reactor, indicating the effect of the substrate type on the community structure. Of the methanogenic archaea, methanogens of the genus Methanosarcina were found in high proportions in both reactors with specific methanosarcinas in each reactor, whereas the strict hydrogenotrophic methanogens of Methanoculleus sp. were found at significant levels only in the reactor fed with chicken/swine manure (based on the analyses of 16S rRNA gene). This suggests that among methanogenic archaea, Methanosarcina species which have different metabolic capabilities, including aceticlastic and hydrogenotrophic methanogenesis, were mainly involved in anaerobic digestion of turkey wastes

Fe(III) mineral reduction followed by partial dissolution and reactive oxygen species generation during 2,4,6-trinitrotoluene transformation by the aerobic yeast Yarrowia lipolytica

© 2015, Ziganshin et al.; licensee Springer. Understanding the factors that influence pollutant transformation in the presence of ferric (oxyhydr)oxides is crucial to the efficient application of different remediation strategies. In this study we determined the effect of goethite, hematite, magnetite and ferrihydrite on the transformation of 2,4,6-trinitrotoluene (TNT) by Yarrowia lipolytica AN-L15. The presence of ferric (oxyhydr)oxides led to a small decrease in the rate of TNT removal. In all cases, a significant release of NO2 − from TNT and further NO2 − oxidation to NO3 − was observed. A fraction of the released NO2 − was abiotically decomposed to NO and NO2, and then NO was likely oxidized abiotically to NO2 by O2. ESR analysis revealed the generation of superoxide in the culture medium; its further protonation at low pH resulted in the formation of hydroperoxyl radical. Presumably, a fraction of NO released during TNT degradation reacted with superoxide and formed peroxynitrite, which was further rearranged to NO3 − at the acidic pH values observed in this study. A transformation and reduction of ferric (oxyhydr)oxides followed by partial dissolution (in the range of 7–86% of the initial Fe(III)) were observed in the presence of cells and TNT. Mössbauer spectroscopy showed some minor changes for goethite, magnetite and ferrihydrite samples during their incubation with Y. lipolytica and TNT. This study shows that i) reactive oxygen and nitrogen species generated during TNT transformation by Y. lipolytica participate in the abiotic conversion of TNT and ii) the presence of iron(III) minerals leads to a minor decrease in TNT transformation

Polymorphism and thermodynamic properties of chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II) complex

© 2016 Elsevier B.V. All rights reserved. A new crystalline polymorph of known chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II) complex [RuCl(PPh3)2(η5-C5H5)] was obtained and characterized by various analytical methods including single-crystal and powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC) in combination with thermo-gravimetric analysis (TG-DSC). The obtained crystals of new polymorph are monoclinic, space group P21/n, with a = 11.125(4), b = 19.184(6), c = 15.946(5) Å, α = 90, β = 100.174(5), γ = 90, and Z = 4. It has been found that real melting point of the complex (M.p. = 252-253 °C) can be determined only in inert atmosphere while an apparent melting is observed in the range 142-150 °C due oxygen promoted oxidative dissociation of triphenylphosphine ligand

Mediators and biomarkers of inflammation in meningitis: Cytokine and peptidome profiling of cerebrospinal fluid

© 2016, Pleiades Publishing, Ltd.Differential diagnosis of bacterial and viral meningitis is an urgent problem of the modern clinical medicine. Early and accurate detection of meningitis etiology largely determines the strategy of its treatment and significantly increases the likelihood of a favorable outcome for the patient. In the present work, we analyzed the peptidome and cytokine profiles of cerebrospinal fluid (CSF) of 17 patients with meningitis of bacterial and viral etiology and of 20 neurologically healthy controls. In addition to the identified peptides (potential biomarkers), we found significant differences in the cytokine status of the CSF of the patients. We found that cut-off of 100 pg/ml of IL-1β, TNF, and GM-CSF levels discriminates bacterial and viral meningitis with 100% specificity and selectivity. We demonstrated for the first time the reduction in the level of two cytokines, IL-13 and GM-CSF, in the CSF of patients with viral meningitis in comparison with the controls. The decrease in GM-CSF level in the CSF of patients with viral meningitis can be explained by a disproportionate increase in the levels of cytokines IL-10, IFN-γ, and IL-4, which inhibit the GM-CSF expression, whereas IL-1, IL-6, and TNF activate it. These observations suggest an additional approach for differential diagnosis of bacterial and viral meningitis based on the normalized ratio IL-10/IL-1β and IL-10/TNF > 1, as well as on the ratio IFN-γ/IL-1β and IFN-γ/ TNF < 0.1. Our findings extend the panel of promising clinical and diagnostic biomarkers of viral and bacterial meningitis and reveal opposite changes in the cytokine expression in meningitis due to compensatory action of proand antiinflammatory factors