Incorporating activated charcoal (AC) in culture media has been shown to affect growth and development of various organisms. Since AC stimulates the development of tobacco haploid plantlets from cultured anthers, research was conducted to determine the effect of activated charcoal on pith-derived callus growth and shoot development in Nicotiana tabacum cv. Wisconsin 38. Our results indicate that the hormones required for callues growth and shoot development in Wisconsin-38 tobacco are adsorbed by AC, thereby inhibiting callus growth and prohibiting shoot development. This effect was observed even when AC was removed from the medium by filtration prior to culturing the callus.

Callus was induced in different somatic organs of Oryza sativa L. Specific minimum 2,4‐dichlorophenoxyacetic acid (2,4‐D) concentrations in the medium were necessary for the induction of callus from different organs while high levels of 2,4‐D (6–10 mg/l) induced callus formation in each organ tested. The optimum 2,4‐D concentration for callus induction and growth for root‐derived calli was 2 mg/l and for leaf‐derived 6 mg/l. Root and shoot organogenesis were induced in both root‐ and leaf‐derived calli by sub‐culturing to a medium lacking 2,4‐D. Root organogenesis occurred at a higher frequency than shoot organogenesis. Shoot organogenesis rarely occurred in calli without differentiated roots. Increased age of callus cultures almost completely inhibited shoot development. The addition of the cytokinin 6‐γ,γ‐dimethylallyl‐amino purine partially restored the potential for shoot organogenesis. Whole plants were easily recovered from the calli and grown to maturity with some plants exhibiting phenotypic abnormalities.

Rigor-index in market-size striped catfish (Pangasianodon hypophthalmus, locally called Thai-Pangas) was determined to assess fillet yield for production of value-added products. In whole fish, rigor started within 1 hr after death under both iced and room temperature conditions while rigor-index reached a maximum of 72.23% within 8 hr and 85.5% within 5 hr at room temperature and iced condition, respectively, which was fully relaxed after 22 hr under both storage conditions. Post-mortem muscle pH decreased to 6.8 after 2 hr, 6.2 after 8 hr and sharp increase to 6.9 after 9 hr. There was a positive correlation between rigor progress and pH shift in fish fillets. Hand filleting was done post-rigor and fillet yield experiment showed 50.4±2.1% fillet, 8.0±0.2% viscera, 8.0±1.3% skin and 32.0±3.2% carcass could be obtained from Thai-Pangas. Proximate composition analysis of four regions of Thai-Pangas viz., head region, middle region, tail region and viscera revealed moisture 78.36%, 81.14%, 81.45% and 57.33%; protein 15.83%, 15.97%, 16.14% and 17.20%; lipid 4.61%, 1.82%, 1.32% and 24.31% and ash 1.09%, 0.96%, 0.95% and 0.86%, respectively indicating suitability of Thai-Pangas for production of value-added products such as fish fillets.

Study was conducted to determine the heavy metal concentration in 5 freshwater fishes Heteropneustes fossilis, Clarias batrachus, Anabus testudineus, Oreochromis niloticus, and Mystus gulio during autumn and winter. Most widely eaten five freshwater fish species were selected for this purpose. These fish species were Among the heavy metals estimated in this study (Cd, Cr, Pb, Cu, Zn) the Cd, Cu, Zn were within the acceptable level but Cr and Pb concentration was above the maximum allowable limit. The Cd, Cr, Pb concentration in the fish muscle was higher in winter as compared to that of autumn but the Cu and Zn concentration was higher in autumn when compared to that of winter. Result of the present research indicates that the heavy metal concentration in fish muscle significantly varies with season. Some heavy metal were within the acceptable level in autumn season but above the maximum allowable limit in winter season. In H. fossilis, C. batrachus, and O. niloticus, heavy metal concentration was within the acceptable level but in A. testudineus and M. gulio heavy metal concentration was above the maximum allowable limit. So heavy metal concentration varied with season as well as with species of fish.

No abstract