Bacterial and fungal diversity in the traditional Chinese liquor fermentation process.

This study endeavored to investigate the variability of bacteria and fungi present during the fermentation process of the light-fragranced distilled liquor known as Fen liquor. To accomplish this, we used a combination of clone libraries of 16S rRNA genes, bar-coded pyrosequencing of the internal transcribed spacer region 1 (ITS1), and quantitative real-time PCR (qPCR). Fifteen families of bacteria and six families of fungi were detected. More than 91% of 16S rRNA gene sequences could be assigned to the family Lactobacillaceae, which were then classified to eight different operational taxonomic units (OTUs), based on a 3% cut-off. The most abundant OTU which contributed to 51% of the total 16S rRNA gene sequences was affiliated with Lactobacillus acetotolerans and had a significantly similar variation trend with the chemical constituents detected. Sixty percent of the fungal ITS1 region sequences were affiliated with the family Saccharomycetaceae. The most abundant OTU was very similar to Issatchenkia orientalis, which displayed notable similarities with respect to the change trends in both ethanol and organic acid contents. The sequences of the second most abundant OTU were closest to Saccharomyces cerevisiae, an important species in the process of ethanol production. Furthermore, about one fourth of the ITS1 region sequences belonged to the family Saccharomycopsidaceae. Conversely, very few sequences could be grouped together with filamentous fungi. The results of qPCR showed that the content of bacteria was increased while that of fungi was more stable in the fermentation process. It is very important to simultaneously investigate bacterial and fungal variations in food-fermentation processes.

[A new SVRDF 3D-descriptor of amino acids and its application to peptide quantitative structure activity relationship].

To establish a new amino acid structure descriptor that can be applied to polypeptide quantitative structure activity relationship (QSAR) studies, a new descriptor, SVRDF, was derived from a principal components analysis of a matrix of 150 radial distribution function index of amino acids. The scale was then applied in three panels of peptide QSAR that were molded by partial least squares regression. The obtained models with the correlation coefficients (R2(cum)), cross-validation correlation coefficients (Q2(cum)) were 0.766 and 0.724 for 48 bitter tasting dipeptides; 0.941 and 0.811 for 21 oxytocin analogues; 0.996 and 0.919 for 20 thromboplastin inhibitors. Satisfactory results showed that information related to biological activity can be systemically expressed by SVRDF scales, which may be an useful structural expression methodology for the study of peptides QSAR.

[Quantitative structure-activity relationship study of tetrahydroimidazobenzodiazepinone anti-HIV drug using three-dimensional holographic vector of atomic interaction field].

AIM: To study the quantitative structure-activity relationship ( QSAR) of 23 tetrahydroimidazobenzodiazepinone (TIBO) as anti-HIV drug. METHODS: A newly developed three-dimensional holographic vector of atomic interaction field (3D-HoVAIF) was used to describe the chemical structure of anti-HIV drug-23 TIBO, a partial least square regression (PLS) model was built. RESULTS: The obtained model with the cumulative multiple correlation coefficient (Rcum(2)), cumulative cross-validated (Qcum(2)) and standard error of estimation (SD) were Rcum(2) = 0. 824, Qcum(2) = 0.778 and SD = 0.56, respectively. The model had favorable estimation stability and good prediction capabilities. CONCLUSION: Satisfactory results showed that 3D-HoVAIF with definite physic-chemical meanings and easy structural interpretation for structural characterization could preferably express information related to biological activity of TIBO.