Moniliella spathulata, an oil-degrading yeast, which promotes growth of barley in oil-polluted soil

The yeast strain Moniliella spathulata SBUG-Y 2180 was isolated from oil-contaminated soil at the Tengiz oil field in the Atyrau region of Kazakhstan on the basis of its unique ability to use crude oil and its components as the sole carbon and energy source. This yeast used a large number of hydrocarbons as substrates (more than 150), including n-alkanes with chain lengths ranging from C10 to C32, monomethyl- and monoethyl-substituted alkanes (C9–C23), and n-alkylcyclo alkanes with alkyl chain lengths from 3 to 24 carbon atoms as well as substituted monoaromatic and diaromatic hydrocarbons. Metabolism of this huge range of hydrocarbon substrates produced a very large number of aliphatic, alicyclic, and aromatic acids. Fifty-one of these were identified by GC/MS analyses. This is the first report of the degradation and formation of such a large number of compounds by a yeast. Inoculation of barley seeds with M. spathulata SBUG-Y 2180 had a positive effect on shoot and root development of plants grown in oil-contaminated sand, pointing toward potential applications of the yeast in bioremediation of polluted soils. Key points • Moniliella spathulata an oil-degrading yeast • Increase of the growth of barley

Pharmacophore based QSAR modelling of natural leads in antimicrobial drug design.

: To separate and optimize the bioactive fraction of Hemidesmus indicus as an antimicrobial lead using insilico QSAR model development.:Hemidesmus indicus was extracted by soxhalation. The crude extract is fractionated using solvents of different polarity and assessed for its antimicrobial activity. The bioactive fraction is further analysed by GC-MS to analyse the constituents. These moieties were studied for their molecular interaction using CoMFA based QSAR model development. The bioactive fraction found to have antibacterial and antifungal activities. GC-MSVersionrevealedthepresenceofeicosae,pthalic acid, oleanen 3 -yl acetate and substituted alkanes. Force field analysis followed by simulation revealed that pthalic acid was found to have interaction with the recept:Thus the integration of activity guided fractionation with cheminformatics may reveal the putative leads in Pthalic acid analogues can thus be optimized further by subjecting

Prediction of octane numbers of substituted alkanes according to the topological characteristics of the molecules

There may occur a special mode of combustion of the fuel-air mixture called detonation, when using motor fuel with a low octane rating. Methods of mathematical modeling are currently used to quickly determine octane numbers without using of expensive equipment. A nonlinear multidimensional QSPR regression model is proposed to predict the octane number of normal and substituted alkanes-gasoline components. The model associates octane numbers with a set of descriptors (topological characteristics of molecular graphs): the Randic index, the Wiener index, and the functions of the eigenvalues of the topological matrix of the molecule, reflecting the main structural and chemical factors, such as branching, the length of the carbon structure and the energy parameters of the molecules, for example perturbation of Hückel spectrum of molecules, as well as affecting octane numbers. The substituted alkanes were used as research objects. A studied sample included 36 hydrocarbons from the homolologus serious of substituted alkanes. The proposed model adequately describes the octane number of alkanes. The coefficient of determination of the model is 0.972. The model was tested on 19 substances which were not included in the base series. The average, absolute and relative error for the test sample of octane numbers were 1.5 units and 2.7% respectively. The model is applicable for engineering and scientific forecasts of octane numbers of various alkanes in motor fuel.

Synthesis, diuretic activity research and QSAR-analysis of N-(1,3,4-tiadiazol-2-il)substituted amides of alkanecarboxylic acids

Diuretics are effective drugs that are widely used in medicine, but have unwanted side effects. The derivative of thiadiazole – acetozolamide is a known diuretic. Therefore, the search for diuretics in this series and the establishment of quantitative «structure–activity» (QSAR) dependencies is appropriate. The aim of the work was to synthesis N-(1,3,4-thiadiazol-2-yl)substituted alkanes of alkanecarboxylic acids, study their diuretic activity, and QSAR analysis. The objects of the study were N-(1,3,4-thiadiazol-2-yl)substituted alkanes of alkanecarboxylic acids, obtained by the interaction of 2-amino-5-alkyl-1,3,4-thiadiazole with the corresponding acylchlorides. Investigation of diuretic activity of synthesized compounds was carried out by the method of Berchin. Hyper-Chem and BuildQSAR software were used for calculation of molecular descriptors and QSAR-models. Synthesis of 12 N-(1,3,4-thiadiazol-2-yl)substituted amides of alkanecarboxylic acids, the structure of which was confirmed by PMR spectroscopy and elemental analysis. Studies of diuretic activity showed that the synthesized compounds had pronounced diuretic properties, and some of them according to activity indicators were approaching or exceeding comparative preparations. Compound N-(5-methyl-[1,3,4]thiadiazol-2-yl) propionamide showed the best diuretic effect: increased daily diuresis in white rats, in comparison with intact control, in 2.47 times (p ≤ 0,001), in comparison with hydrochlorothiazide was in 1,6 times and acetazolamide was 1,75 times. The calculation of the molecular descriptors of N-(1,3,4-thiadiazol-2-yl)substituted amides of alkanecarboxylic acids was conducted. Based on the calculated values of molecular descriptors and diuretic activity values of 12 synthesized compounds, a QSAR analysis was performed. Analysis of structure-diuretic activity showed the greatest influence of lipophilicity, energy parameters, spatial structure and size of the molecule. Moreover, diuretic activity increases with increasing logP, decreasing the refractive, volume and area of the molecule, increasing the energy of the higher occupied molecular orbital. Increasing the charge on the Sulfur atom of the thiadiazole ring and the Оxygen atom of the carbonyl group, reducing the angle between the Sulfur atoms, the Nitrogen of the amide group and the Oxygen, and increasing the angle between the Nitrogene atoms of the thiadiazole ring, the Oxygen and the Nitrogen of the amide group, also increases diuretic activity. The results of the diuretic activity of the synthesized compounds N-(1,3,4-thiadiazol-2-yl)substituted amides of alkanecarboxylic acids show the potential for the search for diuretic agents among 1,3,4-thiadiazole derivatives. The resulting QSAR models will be used to modelling and prediction the activity of new potential diuretics.