Homology modeling, molecular docking and molecular dynamics studies of the catalytic domain of chitin deacetylase from Cryptococcus laurentii strain RY1.

This study provides structural insights into chitin deacetylase, over-expressing under nitrogen limiting condition in Cryptococcus laurentii strain RY1. The enzyme converts chitin, the second most abundant natural biopolymer, to chitosan, which offers tremendous applications in diverse fields. To elucidate the structure-function relationship of this biologically and industrially important enzyme, a homology model of the catalytic domain was constructed.

Antibacterial Activity of Polyphenolic Fraction of Kombucha Against Enteric Bacterial Pathogens.

The emergence of multi-drug-resistant enteric pathogens has prompted the scientist community to explore the therapeutic potentials of traditional foods and beverages. The present study was undertaken to investigate the efficacy of Kombucha, a fermented beverage of sugared black tea, against enterotoxigenic Escherichia coli, Vibrio cholerae, Shigella flexneri and Salmonella Typhimurium followed by the identification of the antibacterial components present in Kombucha. The antibacterial activity was evaluated by determining the inhibition zone diameter, minimal inhibitory concentration and minimal bactericidal concentration.

Kombucha tea fermentation: Microbial and biochemical dynamics.

Kombucha tea, a non-alcoholic beverage, is acquiring significant interest due to its claimed beneficial properties. The microbial community of Kombucha tea consists of bacteria and yeast which thrive in two mutually non-exclusive compartments: the soup or the beverage and the biofilm floating on it. The microbial community and the biochemical properties of the beverage have so far mostly been described in separate studies.

Expression of a chitin deacetylase gene, up-regulated in Cryptococcus laurentii strain RY1, under nitrogen limitation.

This study reports the identification of a chitin deacetylase gene in Cryptococcus laurentii strain RY1 over-expressing under nitrogen limitation by differential display. The up-regulation took place in robustly growing cells rather than in starving quiescent autophagic cells. Quantitative Real Time-PCR, enzyme activity in cell lysate and cell wall analysis corroborated the up-regulation of chitin deacetylase under nitrogen limitation.

Bioprotective potential of bacteriocinogenic Enterococcus gallinarum strains isolated from some Nigerian fermented foods, and of their bacteriocins.

Enterococcus gallinarum strains isolated from some Nigerian fermented foods were found to produce bacteriocins. The bacteriocins had a broad spectrum of activity against both Gram-positive and negative bacteria. The effects of the bacteriocins and bacteriocinogenic organ- isms on Staphylococcus aureus infections in rats were evaluated.

Nitrogen fixation in Asaia sp. (family Acetobacteraceae).

The genus Asaia (family Acetobacteraceae) was first introduced with a single species-Asaia bogorensis and later six more species were described namely A. siamensis, A. krungthepensis, A.

Mercuric ion stabilizes levansucrase secreted by Acetobacter nitrogenifigens strain RG1(T).

The purification and characterization of an extracellular levansucrase enzyme produced by novel nitrogen-fixer Acetobacter nitrogenifigens strain RG1(T) is described. Culture conditions were optimized for maximum levansucrase production. Levansucrase purified to homogeneity by tenfold purification has a molecular weight of 65 kDa, contained four cysteine residues, polymerized raffinose and was stable for 21 days at pH 6.