No abstract

Kombucha is a traditional fermented drink and has recently gained popularity due to its numerous claims on therapeutic effects. It is prepared by sweetening black tea and fermented using a symbiotic culture of acetic acid bacteria and yeasts known as SCOBY. The drink can also be brewed using different type of tea and carbon sources. An investigation was conducted to characterize the antioxidant and antimicrobial properties of kombucha by variation of carbon sources: white sugar (S), jaggery (J) and Kelulut honey (H) in black tea (BT) and green tea (GT) media over a period of 7, 14, 28 and 60 days. The antioxidant and antimicrobial efficacy were tested post fermentation. All samples shown the highest value of DPPH inhibition for antioxidant activity at 7 days of fermentation but subsequently decreased with longer fermentation time except for the combination of green tea with jaggery (GT+J). Fermentation of green tea with white sugar (GT+S) showed the highest value with 84%. On the other hand, black tea with jaggery (BT+J) showed least DPPH activity, 9%. Fermentation with green tea demonstrated a higher antioxidant activity compared to black tea, whereas fermentation of any tea with jaggery showed the least antioxidant activity in comparison to white sugar and honey. Thus, it can be said that extended periods of fermentation reduce the DPPH inhibition of kombucha and jaggery itself as carbon source shows an interesting property. Antimicrobial activity was tested using disk diffusion method against E. coli, S. aureus, P. aeruginosa, B. subtilis and S. marcescens. The efficacy increases with time of fermentation for all combinations. Combination of black tea with all carbon sources was found to have most antimicrobial activity.

Molluscan rhogocytes are known to be the only cells able to synthesize hemocyanin that is one of the largest respiratory proteins in nature. However, investigation of rhogocyte cells in vitro is limited due to difficulty in isolating and establishing marine cell culture. The aim of this study was to investigate the nature and distribution of rhogocyte cells of Haliotis laevigata in the mantle tissue with respect to the expression of the two known isoforms of hemocyanin. Rhogocyte cells were identified using immunofluorescence-fluorescence in situ hybridization (IF-FISH) that involved simultaneous staining of localized hemocyanin by a polyclonal antibody while the mRNA was hybridized with FISH probes. The distribution of rhogocyte cells was demonstrated using flow cytometry, followed by cell sorting with fluorescence-activated cell sorter (FACS) and confocal microscope imaging for further characterization. Our results suggested that the mantle tissue is dominated by two distinct populations of rhogocyte cells that synthesize hemocyanin type 1. Observation with confocal microscopy of both populations revealed hemocyanin localization in the periphery of the cell membrane. Cell population with higher antibody signal had irregular and elongated cell morphology with punctate mRNA probe signals. The second population with lower antibody signal had ovoid morphology and wide distribution of mRNA probe signals. We suggest that these populations represent two distinct phases of hemocyanin biosynthesis of a single isoform, which is closely related to Haliotis tuberculata type 1 hemocyanin (HtH1). The knowledge acquired in this study enhances the understanding of the biology of rhogocyte cells and biosynthesis of hemocyanin.

This study aims to evaluate the effect of Fermented Rice After-wash Water (FRAW) on chilli growth and to isolate microorganism present in three brands of white rice FRAW. The study showed that FRAW treatment was comparable with NPK fertiliser. In addition, a number of plant growth-promoting microbes associated with FRAW were also isolated. Isolated bacteria and fungi were then characterised according to their morphology and biochemical analysis. Thus the positive effect of FRAW on the chilli was likely due to the plant growth promoting microorganism present in FRAW.