Characterization and DNA methylation modulatory activity of gold nanoparticles synthesized by Pseudoalteromonas strain

Marine extremophiles are shown to tolerate extreme environmental conditions and have high metal reducing properties.Here, we report intracellular synthesis of gold nanoparticles (AuNP) by marine extremophilic bacteria Pseudoalteromonassp. Bac178 which was isolated from the OMZ of Arabian Sea. Preliminary observations suggest that these bacteria usedifferent pathways which may involves the membrane as well as intracellular proteins for the gold salt reduction. Characterization of the biosynthesised nanoparticles by various techniques such as Scanning electron microscopy (SEM),Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS)confirmed the presence of crystalline gold. These biologically synthesized AuNP were investigated for cytotoxicity andoxidative stress generation in human normal fibroblast and melanoma cells (A375). As AuNP are envisaged to find manyapplications in the medical field, it was of interest to study the effect of AuNP at the epigenetic level. They were found to benon-cytotoxic, non-genotoxic and non-oxidative stress generating over a range of concentrations. Exposure to these AuNPis observed to cause alterations in global DNA methylation as well as in the expression of DNA methyltransferase (DNMT)genes. Since biosynthesized AuNP are being used in various applications and therapies, their epigenetic modulatory activityneeds careful consideration.

Study of inheritance of diabetes mellitus in Western Indian population by pedigree analysis.

OBJECTIVES: To study the inheritance pattern of diabetes mellitus in Western Indian population by analysing the pedigree of diabetes patients. METHODS: 3,921 individuals from 300 families were interviewed for family history in this study, out of which 770 were diabetic individuals. Statistical analysis of the data was carried out using T-test and Chi-square test. RESULTS: 37% cases of Type 1 DM and 58% cases of Type 2 DM showed family history of the disease. Of the cases showing family history for diabetes, 92% in case of Type 1 DM and 59% in case of Type 2 DM showed family history of Type 2 DM with a decrease in age of onset in the successive generations. Both the parents, when diabetic conferred equal risk of inheriting diabetes in offspring. The sex ratio of offspring suffering from diabetes was not influenced when only one of the parents was diabetic. However it was observed that the male offspring were highly susceptible when both parents were diabetic (Chi-square value=4.55 with 1 d.f.). The age of onset of diabetes did not show significant correlation with whether one or both the parents were diabetic. However, it was noteworthy that in case of familial history of diabetes there was a decrease in the age of onset in successive generations. CONCLUSION: This study suggests that family history of diabetes results in predisposition to early onset of the disease in successive generations and a cluster of genes involved in Type 2 DM may show a parental effect for predisposition to Type 1 DM in the offspring in this set of Indian population.

The inactive X chromosome in the human female is enriched in 5-methylcytosine to an unusual degree and appears to contain more of this modified nucleotide than the remainder of the genome.

By employing a procedure that combines ELISA and photoacoustic spectroscopy, we have examined the content of 5-methylcytosine (m(5)C) in DNA of individuals who differed from one another in the number of X chromosomes in their genomes. The results show that the human inactive X chromosome (Xi) contains very high amounts of this modified nucleotide. We estimate that in the 46,XX female there is more m(5)C in Xi (~ 3.6 x 10(7)) than in all the remaining chromosomes put together (~ 2.1 x 10(7)). Our results also suggest that nearly one-fifth of all cytosines in Xi are methylated and that, in addition to CpG methylation, there is extensive non-CpG methylation as well.