R. Preetha

Optimization of carbon and nitrogen sources and growth factors for the production of an aquaculture probiotic (Pseudomonas MCCB 103) using response surface methodology

Aim:  To develop a new medium for enhanced production of biomass of an aquaculture probiotic Pseudomonas MCCB 103 and its antagonistic phenazine compound, pyocyanin.

Optimization of medium for the production of a novel aquaculture probiotic, Micrococcus MCCB 104 using central composite design

A marine isolate ofMicrococcus MCCB 104 has been identified as an aquaculture probiotic antagonistic toVibrio. In the present study different carbon and nitrogen sources and growth factors in a mineral base medium were optimized for enhanced biomass production and antagonistic activity against the target pathogen,Vibrio harveyi, following response surface methodology (RSM). Accordingly the minimum and maximum limits of the selected variables were determined and a set of fifty experiments programmed employing central composite design (CCD) of RSM for the final optimization. The response surface plots of biomass showed similar pattern with that of antagonistic activity, which indicated a strong correlation between the biomass and antagonism. The optimum concentration of the carbon sources, nitrogen sources, and growth factors for both biomass and antagonistic activity were glucose (17.4 g/L), lactose (17 g/L), sodium chloride (16.9 g/L). ammonium chloride (3.3 g/L), and mineral salts solution (18.3 mL/L).

Enantioselective oxidation of secondary alcohols by Candida parapsilosis ATCC 7330

Optically pure allylic alcohols and 4-phenylbutan-2-ols were prepared by oxidative kinetic resolution using whole cells of Candida parapsilosis ATCC 7330. Only the ‘S’ enantiomer is selectively oxidized to the corresponding keto compound (yield, 37–46%) leaving the ‘R’ alcohol (yield, 37–52% and ee 46 to >99%). The biocatalytic method is carried out under mild conditions at 20 °C, pH 6.5 in phosphate buffer.

Norbornene derived nanocarrier reduces isoniazid mediated liver toxicity: assessment in HepG2 cell line and zebrafish model

The aim of this study was to investigate the protective effect of the stimuli-responsive norbornene-based nanocarrier complex of isoniazid, compared to pure isoniazid, on liver cells, by in vivo and in vitro methods. Hepatic damage induced in a zebrafish model by isoniazid resulted in significant alterations in liver histology, gene expression of drug metabolizing genes, reduced glutathione (GSH) levels, and DNA damage. An increased level of intracellular reactive oxygen species (ROS) was detected in HepG2 cells on exposure to isoniazid. Interestingly, the isoniazid conjugated nanocarrier exhibited a more protective effect on liver cells compared to isoniazid. A significant reduction in the cyp2p6 gene, elevation in GSH levels, reduced DNA damage, and a normal histological tissue pattern was observed in liver tissues exposed to the isoniazid conjugated nanocarrier. Also, the isoniazid conjugated nanocarrier showed negligible ROS generation and in vitro cytotoxicity in HepG2 cells. These encouraging results may prompt further research in the advance of norbornene-based nano systems in nanotherapeutics and biomedical applications.

Microencapsulation of Lactobacillus Sp. using Two Different Materials and Comparison for Encapsulation Efficiency

Probiotics are microorganisms which, when taken orally, provide beneficial effects on human gut health. Microencapsulation of probiotics is a technique that is currently receiving considerable interest as it helps probiotics to survive against adverse environmental conditions in the human body. In this project , a study to determine the stronger encapsulating material is done by encapsulating Lactobacillus sp. using alginate and skim milk alginate. The encapsulation was done by extruding into 100mM CaCl2 solution. Viability test, bile salt tolerance test and storage stability was performed. On analyzing the results it was found that, the skim milk alginate beads had the efficiency of 96.48%. The bacteria encapsulated using skim milk alginate was more viable and more tolerant towards bile salt. The storage stability test was carried out for a period of 28 days and it was found that the probiotic encapsulated using skim milk alginate were more viable. From the results it was concluded that skim milk alginate was a stronger encapsulating material than alginate because of the strong network forming nature of milk proteins.