ABSTRACT
Halotolerant Bacillus aquimaris VITP4, isolated from Kumta coast (India), was used to produce extracellular α-amylase. The production was found to be maximal after 24 h of growth at pH 8.0 and 40 oC. Optimal activity of the purified enzyme was in the pH range of 7.5 – 9.5 at 40 oC. The enzyme was found to retain more than 60% of the initial activity even at NaCl concentration of 3.5 M, indicating that it is halotolerant. Calcium ion (0.01 mM) and CTAB (10 mM) enhanced the activity whereas EDTA decreased the enzymatic activity. Thermal inactivation kinetics suggested that the enzyme exhibits reversible unfolding even at high temperature (till 90 oC) and the t1/2 at 90 oC was found to be 43.5 min. These results suggests that the α-amylase from Bacillus aquimaris strain VITP4 is halotolerant, metal ion dependent enzyme which is stable in the presence of cationic detergent and moderate temperature conditions.
ABSTRACT
PURPOSE: One hundred and ten Helicobacter pylori isolates from peptic ulcer disease patients and matched controls were analysed for any possible relationship between the presence of cryptic plasmids and their antibiotic sensitivity pattern. METHODS: Antral biopsies of patients with gastric and duodenal ulcer, gastric cancer, non ulcer dyspepsia and matched controls were cultured for H.pylori. Antibiotic susceptibility and MIC analysis of the clinical isolates was done by E-test. Plasmid profiles of the isolates were analysed using mini ultra prep plasmid kit. RESULTS: Out of the 110 isolates tested, 89.1% isolates were resistant to metronidazole, 10.9 % were resistant to clarithromycin and 0.9% were resistant to multiple drugs. Isolates harbouring plasmids were seen in all the groups and constituted 5.4% of total isolates. CONCLUSIONS: The presence of plasmids in the clinical isolates of H.pylori did not have any correlation with their antibiotic resistance pattern.
ABSTRACT
Genomic library of Mycobacterium tuberculosis (SIHV) was constructed into T7 promoter based vector pBluescript II KS (+/-) in Escherichia coil. The expression of mycobacterial antigens from recombinants was detected by immunoscreening using E-coli-preabsorbed hyperimmune rabbit anti-M tuberculosis cell wall associated proteins serum. Among 980 clones tested by immunoscreening, a clone pJJ5 was found to produce mycobacterial antigen. This clone was further characterized by immunoblotting and found to produce a 36 kDa of cell wall associated antigen Detection of antibodies response to this antigen in the serum of the majority of the individuals with tuberculosis indicates that this antigen is capable of stimulating a humoral immune response.