The microbial production of gluconic acid has been investigated using a mutant Gluconobactor oxydans GPM 60 through optimization of some Physical parameters. Production conditions like initial pH, incubation period, volume of media, age of inoculum, volume of inoculum, agitation and temperature were individually opitimized one by one. The maximum yield of gluconic acid is 13.80 g/L with pH 6.0, 96h incubation, 20 ml medium, 48h age of inoculum, 10 ml volume of inoculum, 250 rpm agitation and 30°C temperature.

The availability of the stinging catfish, Heteropneustes fossilis has been declined in the natural water bodies in Bangladesh in the last two decades. Thus, it is a great concern whether the reduction in abundance has had any impact on genetic variability of this species. Randomly Amplified Polymorphic DNA (RAPD) fingerprint was generated to analyze the genetic variation in five different populations of H. fossilis namely Chalan beel (Natore), Pirgonj beel (Rangpur), Mohongonj haor (Netrakona), Belaboo beel (Narsingdi) and a hatchery located in Mymensingh. Four polymorphic decamer primers, out of 30 tested, were selected for Polymerase Chain Reaction and used in the final RAPD analysis of fifteen individuals from each population. These four primers produced 31 scorable bands of which 26 (83.87%) were polymorphic. The proportion of polymorphic loci and gene diversity estimates were 83.87 and 0.3703, respectively in the Mohongonj population indicating the existence of a relatively higher level of genetic variation in this population. All the populations showed almost similar level of intra-population similarity indices. The UPGMA dendrogram based on Nei’s original measures of genetic distance (D) indicated the segregation of five populations into two distinct groups. The four natural populations made one cluster and the hatchery population produced another cluster. RAPD markers could detect variations within and between populations allowing genetic characterization of different populations of H. fossilis.

Methomyl (S-methyl-1-N (methyl carbamoyl) oxy] thio acetimidate, is a N –methyl carbamate broad spectrum insecticide. The methomyl containing technical formulation the “Lannate” was evaluated for its effects on the liver antioxidant contents, oxidative stress by-products and oxidative stress enzyme activities and histopathology in Swiss albino mice. Normal virgin male Swiss albino mice of 90 days old weighing about 25-30g were used in the experiment. The mice were administered 1, 2, 3, and 4mg/kg body wt methomyl for 30 days and effective dose 4 mg for 5, 10, and 20 days to know the dose and durational effect on liver. The mice were sacrificed on day 31st or 24 hours after the terminal exposure. Liver dissected out freed from adherent tissue and weighed to nearest milligram. The liver histology, estimations of antioxidant contents, oxidative stress by-products and oxidative stress enzyme activities were carried out. Liver antioxidant contents showed that levels of GSH (Glutathione) and ascorbic acid were decreased significantly in mice treated with 2, 3 and 4mg/kg/day methomyl and 4 mg/ kg/ day for 10 and 20days of methomyl treatment, except the level of ascorbic acid was not changed significantly in mice treated with 2 mg/kg body wt. Liver antioxidant products showed that levels of TBARS (thiobarbaturic acid) and protein carbonyl were increased significantly in mice treated with 2, 3 and 4mg/kg/day methomyl and 4 mg/ kg/ day for 10 and 20days of methomyl treatment, except the level of TBARS was not changed significantly in mice treated with 2 mg/kg body wt of methomyl. Liver oxidative stress enzyme activities showed that levels of CAT (Catalase), SOD (super oxide dismutase) and GST (Glutathione-s-transferase) were decreased significantly in mice treated with 2, 3 and 4mg/kg/day methomyl and 4 mg/ kg/ day for 10 and 20days of methomyl treatment. The Histology of liver of mice treated with 2, 3 and 4 mg / kg/ day methomyl and 4 mg / kg/ day for 10 and 20days of duration showed that dilation of central vein, sinusoids between hypertrophied hepatocytes and cytoplasmic vacuolization with loss of radial arrangement of cells. The result of the present study suggests that chronic exposure to methomyl insecticide has deleterious effect on liver. The study also revealed that the methomyl might have affected cell metabolism and cell membrane permeability and detoxification system in liver.

Methomyl (S-methyl-1-N [(methyl carbamoyl) oxy] thio acetimidate, is a carbamate broad spectrum insecticide. The Swiss albino mice were administered orally 1, 2, 3, and 4 mg/kg body wt methomyl for 30 days and effective dose 4 mg/kg for 5, 10, and 20 days to know the dose and durational effect on testes and biochemical contents. The mice were sacrificed on day 31st or 24 hours after the terminal exposure. Testes, epididymis, vasa deferentia, seminal vesicles, prostate, coagulatory and Cowper’s glands weight decreased significantly with 2, 3 and 4 mg/kg/day and in 4mg/kg /day for 10 and 20 days of methomyl treatment. Histologic studies of the testes revealed anti-spermatogenic and anti-steroidogenic effects of methomyl reflected by significant decrease in the number and diameter of spermatogonia, primary spematocytes, secondary spermatocytes, spermatids and Leydig cells in the mice treated with 2, 3 and 4 mg/kg/day and in 4 mg/kg /day for 10 and 20 days of methomyl treatment, except with 2 mg/kg/day methomyl treatment number of primary spematocytes, Leydig cells, diameter of spermatogonia, and in 4 mg/kg/day methomyl for 10 days treatment the number of spermatogonia, leydig cells and diameter of primary spermatocytes not changed significantly when compared with controls. Biochemical studies of testis and epididymis showed methomyl at doses of 2, 3 and 4 mg/kg/day and in 4 mg/kg /day for 10 and 20 days of methomyl treatment caused significant decrease in the levels of DNA, RNA, protein, glycogen and sialic acid whereas cholesterol increased significantly. However, treatment with 1, 2 mg / kg/ day and 4 mg / kg /day for 5 days methomyl caused no significant change in epididymal biochemical contents when compared with control. Study on enzyme activities in testis and epididymis revealed that the treatment with 3 and 4 mg/kg/day and 4 mg/kg /day for 20 days of methomyl caused significant decrease in the activities of succinic dehydrogenase (SDH), ions ATPase (Na+-K+ATPase, Ca++ATPase, Mg++ATPase) and acid phosphatase (ACP) were decreased significantly, except with 3 mg/kg/day methomyl treatment where Ca++ ATPase activity in testes and epididymis not changed significantly. However, lactate dehydrogenase (LDH) and alkaline phosphatase (AKP) activities were increased significantly. The testis 3β hydroxysteroid dehydrogenase (3βHSD) decreased significantly with 3 and 4 mg/kg /day and in 4 mg/kg /day for 10 and 20 days of methomyl treatment when compared with controls. However, there was no significant change in testes and accessory reproductive organs, number and diameter of spermatogonia and Leydig cells and biochemical contents of testis and epididymis with 1 mg/kg/day and in 4 mg/kg /day for 5 days of methomyl treatment. These observed effects of methomyl on testes and accessory reproductive organs weight, testis histology, biochemical contents and enzyme activities in testis and epididymis may be due to toxic effect or hormonal imbalance in any of the stage in the hypothalamo-hypophysial-testicular axis.

The present investigation was under taken to select a suitable antibiotic for the treatment of bovine mastitis by conducting antibiotic sensitivity test with different antibiotics and to evaluate the antioxidant property of pigment staphyloxanthin produced by S. aureus against Carbon tetrachloride (CCl4) induced stress in albino mice. In this study a total of 20 samples were screened and out of which 12 samples confirmed Staphylococcus aureus were obtained. The confirmed strains of Staphylococcus aureus were subjected to haemolytic activity. α, β and non-haemolytic activities were, 33.33%, 50% and 16.67% observed respectively among the isolates of Staphylococcus aureus. Antibiotic susceptibility of staphylococcus aureus against 5 antibiotics was tested by using standard antibiotic discs. Ceftriaxone was found to be the most effective drug and also mice is used as a model to study the antioxidant property of staphylococcus aureus pigment against a stress induced by CCl4 in mice. Results showed that animals treated with 1ml/kg body weight of CCl4 for 2 days caused a marked rise in the level of thiobarbituric acid reactive substances (TBARS) and decreased glutathione Reduced glutathione (GSH), Superoxide dismutase (SOD), Catalase (CAT) and Glutathione-S-transferase (GST) levels in the liver, kidney and testis tissue homogenates of CCl4 treated mice. Graded doses of Staphylococcus aureus pigment Staphyloxanthin successfully prevented the alterations of these effects in the experimental mice.