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BackgroundImpaired thermogenesis can promote obesity. Therefore, the aim of this study was to investigate whether the expression of thermogenesis-related genes is altered in adipose tissues of obese individuals and whether excessive methylation of their promoters is involved in this phenomenon.MethodsThe expression of genes encoding β adrenergic receptors (ADRBs), thyroid hormone receptors (THRs), 5’-iodothyronine deiodinases (DIOs), and uncoupling proteins (UCPs) was measured by real-time PCR in visceral and in subcutaneous adipose tissues of 58 obese (BMI >40 kg/m2) and 50 slim (BMI 20-24.9 kg/m2) individuals. The methylation status of these genes was studied by the methylation-sensitive digestion/real-time PCR method.ResultsThe expression of ADRB2, ADRB3, THRA, THRB, DIO2, UCP2 was significantly lower in the adipose tissues of obese patients than in tissues of normal-weight individuals (P < 0.00001). In the obese, the expression of ADRB2, ADRB3, DIO2 was lower in visceral adipose tissue than in subcutaneous adipose tissue (P = 0.008, P = 0.002, P = 0.001, respectively). However, the mean methylation of CpG islands of these genes was similar in tissues with their high and low expression, and there was no correlation between the level of expression and the level of methylation.ConclusionsDecreased expression of thermogenesis-related genes in adipose tissues of obese patients might result in the reduced reactivity to both hormonal and adrenergic stimuli and therefore in a lower potential to activate thermogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0395-2) contains supplementary material, which is available to authorized users.

We observed obesity-associated downregulation of SIRT1 and upregulation of SIRT7 mRNA levels that were not associated with the methylation status of their promoters. We found a negative correlation between mRNA levels of SIRT1 in VAT of obese individuals and SIRT7 in VAT of the normal-weight subjects and expression of the relevant miRNAs.

Appreciable amounts of amide are formed in the course of nitrile hydrolysis in the presence of recombinant nitrilase from Pseudomonas fluorescens EBC 191, depending on the a-substituent and the reaction conditions. The ratio of the nitrilase and nitrile hydratase activities of the enzyme is profoundly influenced by the electronic and steric properties of the reactant. In general, amide formation increased when the a-substituent was electron-deficient; 2-chloro-2-phenylacetonitrile, for example, afforded 89 % amide. We found, moreover, that (R)-mandelonitrile was hydrolysed with 11 % of amide formation whereas 55 % amide was formed from the (S)-enantiomer; a similar effect was found for the O-acetyl derivatives. A mechanism that accomodates our results is proposed.

The precipitation and cross-linking into CLEAs of the hydroxynitrile lyase (E.C. 4.1.2.10) from Manihot esculenta was investigated and an optimized procedure, which involved precipitation with (NH 4 ) 2 SO 4 , was developed. It was found that a fast (photometric) assay severely underestimated the activity recovery in the CLEA due to rate-limiting diffusion, whereas in a synthetic assay the activity recovery was up to 93 % of the starting activity. The CLEA was applied in the hydrocyanation of various aldehydes and ketones in microaqueous medium, conditions that rendered the non-enzymatic background reaction insignificant, even with unreactive substrates.