Identification of a novel variant of hepatitis B virus isolated from patient co-infected with hepatitis C virus.

Hepatitis B virus (HBV) is a major public health concern worldwide. Co-infection of hepatitis B patients with other pathogens intensifies the severity of the disease. We report a novel variant of hepatitis B virus (HBV) in Bangladesh isolated from a patient co-infected with hepatitis C virus (HCV) who exhibited liver cirrhosis. From 150 collected plasma samples, we sequenced HBV complete genome from one HBV-HCV co-infected patient. The complete genome was analysed using bioinformatics tools, NCBI BLAST, Geno2Pheno, and SnapGene software. The strain belongs to genotype A and subgenotype A1. Upon analysing the complete genome of this strain, we found a frameshift deletion of 54 nucleotides at the pre-S2 region, a functional regulator of HBV surface protein. Furthermore, we observed a Y126H mutation in the polymerase protein of this strain. This is the first report with such an unusual pre-S deletion event of the HBV genome in an HCV-co-infected patient associated with liver cirrhosis. These findings may inform scientists about genomic modifications in the HBV genome associated with HCV co-infection.

Association of polymorphism in heat shock protein 70 genes with type 2 diabetes in Bangladeshi population.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a chronic disorder of which stress is a major contributor. Under stressful condition, body synthesizes a family of molecular chaperone called Heat-shock proteins (HSPs). Current study assessed the frequency and association of HSP70-hom + 2,437 T/C polymorphism with T2DM risk among Bangladeshis. METHODS: This polymorphism was selected through bioinformatics analyses and identified by PCR-RFLP method. RESULTS: Bioinformatics analysis identified this SNP as missense mutation which could destabilize the final HSP product. Heterozygous mutant (CT) genotype was significantly associated with T2DM incidence among the studied populations (p = .015). Further analysis revealed a strong association with female patients (p = .002), while the male group showed no association (p = .958). Moreover, the C allele was significantly associated among all diabetic patients (p = .016) and particularly in the female patient group (p = .001). However, under stressful condition, males with CT genotype were at high risk for T2DM incidence whereas, females with CT genotype showed no significant association. CONCLUSIONS: HSP70-hom + 2,437 T/C polymorphism was found to be significantly associated with T2DM incidence in the Bangladeshi population in both stress-dependent and independent manners.

Analysis of the complete genome of hepatitis B virus subgenotype C2 isolate NHB17965 from a HBV infected patient.

The burden of chronic hepatitis B virus (HBV) infections is increasingly detected nowadays. Herein, we report a complete genome of HBV subgenotype C2 (HBV/C2) from a HBV infected patient. Complete genome analysis revealed that the isolated strain was a non-recombinant wild type and had several regular substitutions in the reverse transcriptase domain and small surface proteins of HBV. This study may help clinicians and scientists gain in-depth knowledge on the current substitutions of HBV/C2 genome and to identify potential therapies against HBV infections.

Molecular Identification of a Newly Isolated Bacillus subtilis BI19 and Optimization of Production Conditions for Enhanced Production of Extracellular Amylase.

A study was carried out with a newly isolated bacterial strain yielding extracellular amylase. The phylogenetic tree constructed on the basis of 16S rDNA gene sequences revealed this strain as clustered with the closest members of Bacillus sp. and identified as Bacillus subtilis BI19. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Rice flour (1.25%) as a cheap natural carbon source was found to induce amylase production mostly. A combination of peptone and tryptone as organic and ammonium sulfate as inorganic nitrogen sources gave highest yield. Maximum production was obtained after 24 h of incubation at 37 °C with an initial medium pH 8.0. Addition of surfactants like Tween 80 (0.25 g/L) and sodium lauryl sulfate (0.2 g/L) resulted in 28% and 15% increase in enzyme production, respectively. Amylase production was 3.06 times higher when optimized production conditions were used. Optimum reaction temperature and pH for crude amylase activity were 50 °C and 6.0, respectively. The crude enzyme showed activity and stability over a fair range of temperature and pH. These results suggest that B. subtilis BI19 could be exploited for production of amylase at relatively low cost and time.

Optimization and partial characterization of culture conditions for the production of alkaline protease from Bacillus licheniformis P003.

Proteolytic enzymes have occupied a pivotal position for their practical applications. The present study was carried out under shake flask conditions for the production of alkaline protease from Bacillus licheniformis P003 in basal medium containing glucose, peptone, K2HPO4, MgSO4 and Na2CO3 at pH 10. The effect of culture conditions and medium components for maximum production of alkaline protease was investigated using one factor constant at a time method along with its characterization. Maximum level of enzyme production was obtained after 48h of incubation with 2% inoculum size at 42°C, under continuous agitation at 150 rpm, in growth medium of pH 9. Highest enzyme production was obtained using 1% rice flour as carbon source and 0.8% beef extract as organic nitrogen source. Results indicated that single organic nitrogen source alone was more suitable than using in combinations and there was no significant positive effect of adding inorganic nitrogen sources in basal medium. After optimization of the parameters, enzyme production was increased about 20 fold than that of in basal medium. The crude enzyme was highly active at pH 10 and stable from pH 7-11. The enzyme showed highest activity (100%) at 50°C, and retained 78% relative activity at 70°C. Stability studies showed that the enzyme retained 75% of its initial activity after heating at 60°C for 1h. The enzyme retained about 66% and 46% of its initial activity after 28 days of storage at 4°C and room temperature (25°C) respectively. Mn(2+) and Mg(2+) increased the residual activity of the enzyme, whereas Fe(2+) moderately inhibited its residual activity. When pre-incubated with Tween-20, Tween-80, SDS and H2O2, each at 0.5% concentration, the enzyme showed increased residual activity. These characteristics may make the enzyme suitable for several industrial applications, especially in leather industries.

Production and partial characterization of extracellular amylase enzyme from Bacillus amyloliquefaciens P-001.

Amylases are one of the most important enzymes in present-day biotechnology. The present study was concerned with the production and partial characterization of extracellular amylase from Bacillus amyloliquefaciens P-001. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Enzyme production was induced by a variety of starchy substrate but corn flour was found to be a suitable natural source for maximum production. Tryptone and ammonium nitrate (0.2%) as nitrogen sources gave higher yield compared to other nitrogen sources. Maximum enzyme production was obtained after 48 hrs of incubation in a fermentation medium with initial pH 9.0 at 42°C under continuous agitation at 150 rpm. The size of inoculum was also optimized which was found to be 1% (v/v). Enzyme production was 2.43 times higher after optimizing the production conditions as compared to the basal media. Studies on crude amylase revealed that optimum pH, temperature and reaction time of enzyme activity was 6.5, 60°C and 40 minutes respectively. About 73% of the activity retained after heating the crude enzyme solution at 50°C for 30 min. The enzyme was activated by Ca(2+) (relative activity 146.25%). It was strongly inhibited by Mn(2+), Zn(2+) and Cu(2+), but less affected by Mg(2+) and Fe(2+).