Effect of Dissolved Oxygen on the Growth, Sporulation and Larvicidal Activity of Bacillus sphaericus 2362

Bacillus sphaericus produces bacterial protein toxin capable of killing larvae of mosquitoes which spread diseases such as filariasis, encephalitis and malaria. In batch culture, a maximum spore count of 2.9 x 109/ml media was obtained after 48 h cultivation. In continuous culture, a dilution rate of 0.10 hr- I was found to give a higher spore count than 0.15 h- 1 and 0.2 h- I dilution rates. Kinetic studies on dissolved oxygen (DO) levels showed that 20,50 and 100% gave rapid formation of free spores, whilst 5% DO gave poor results. Cells grown at 5, 20 and 50% DO levels gave comparable values of mosquito-larvicidal activity while those grown at 100% DO were significantly less toxic

Optimization of modified-media containing serum for better rin-5f and brin-bd11 cells monolayer attachment, growth and insulin secretion

A study was undertaken to observe the effect of D-glucose and L-glutamine and the combination of both nutrients at various concentrations towards the growth and insulin production by BRIN-BD11 cells. It was found that at a final concentration of 4 g/L D-glucose and 0.3 g/L L-glutamine in RPMI-1640 media gave maximum cell growth and insulin production of 1.75 x 106 cells/ml from 2.5 x 105 cells/ml and 100.77 µg/L, respectively. The result of this study indicates that D-glucose and L-glutamine promote good cell growth and insulin secretion of BRIN-BD11 cells as a step towards mass propagation of transplantable insulinoma cells and insulin production

Improvement of red-pigment-producing fungal strain (Monascus purpureus FTC 5391) using monospore isolation technique

Monospore isolation technique was performed to obtain the improved strain that has high and consistent ability to produce red pigment. The ability of Monascus purpureus FTC 5391 wild strain in producing red pigment was successfully improved using monospore isolation technique. By using this approach of improvement, three different monospore isolates of M. purpureus FTC 5391 (MP 3, MP 4 and MP 5) were obtained as the best red pigment producers when glucose, potato starch and rice starch were used as carbon source, respectively

Kinetics of red pigment fermentation in 2-litre stirred tank fermenter using different types and concentrations of carbon sources

Kinetics of red pigment fermentation by Monascus purpureus FTC 5391 using various sources of carbon (glucose, fructose, maltose and sucrose) were analysed using a model based on Logistic and Leudeking-Piret equations. Using the optimal concentration of fructose, batch fermentation without pH control was capable to produce slightly higher red pigment (20.70 UA500) as compared to fermentation using glucose (20.63 UA500). In terms of overall productivity, fermentation using fructose (0.153 UA500/h) was comparable to glucose (0.122 UA500/h). The production of red-pigment by M. purpureus FTC 5391 appeared to be a non-growth associated process; whereby rapid red-pigment production occurred during non-growth phase after the depletion of carbon in the medium and the on-set of ethanol accumulation. It seemed that the red-pigment was formed from the metabolism of ethanol accumulated in the culture

Patterns of negotiation of meaning routine in online forum discussion

This study examines a text-based, asynchronous online forum discussion among English language teacher trainers who were involved in a two-week online professional development course. It investigates the participants’ negotiation of meaning routine when they come across new content related item and describes the pattern of this negotiation of meaning routine. A textual analysis method, employing Smith’s (2003) expansion of Varonis and Gass Model (1985) for negotiation of meaning, was utilised to analyse the discussion threads. The analysis revealed that the participants did engage in negotiation of meaning and all the four negotiation of meaning steps (trigger, indicator, response and reply to response) were evident. It was also revealed that content triggers, local indicator, elaboration in responses and task appropriate response were frequently used. As the application of CMD for teaching and learning is increasing, findings of this study could inform educators about the kind of strategies that could enrich online interaction