Different proposed applications of bacteriorhodopsin

Bacteriorhodopsin (BR) is an integral membrane protein found in "purple membrane" (the Archaea cell membrane) mainly in Halobacteria. This protein absorbs green light (wavelength 500-650 nm, with the absorption maximum at 568 nm) and converts it into an electrochemical gradient. This gradient in turn is used for ATP production. The ability of BR to convert light energy into chemical energy or sunlight into electricity has been used in different applications mainly optical appliances but also for therapeutic/medical applications and research. This review surveys some of these applications that have been patented in the last five years.     

Dissecting the mechanism and assembly of a complex virulence mycobacterial lipid

Mycobacterium tuberculosis cell envelope is a treasure house of biologically active lipids of fascinating molecular architecture. Although genetic studies have alluded to an array of genes in biosynthesis of complex lipids, their mechanistic, structural, and biochemical principles have not been investigated. Here, we have dissected the molecular logic underlying the biosynthesis of a virulence lipid phthiocerol dimycocerosate (PDIM). Cell-free reconstitution studies demonstrate that polyketide synthases, which are usually involved in the biosynthesis of secondary metabolites, are responsible for generating complex lipids in mycobacteria. We show that PapA5 protein directly transfers the protein bound mycocerosic acid analogs on phthiocerol to catalyze the final esterification step. Based on precise identification of biological functions of proteins from Pps cluster, we have rationally produced a nonmethylated variant of mycocerosate esters. Apart from elucidating mechanisms that generate chemical heterogeneity with PDIMs, this study also presents an attractive approach to explore host-pathogen interactions by altering mycobacterial surface coat.     

Migration events play significant role in genetic differentiation: A microsatellite-based study on Sikkim settlers

Background  

A wide spectrum of genetic diversity in mongoloids of India is well documented. Though all mongoloids of India are known to have originated from the Mongol region of China but the period and route of migration from their native land to different Himalayan regions is little known. Thus the studies on genomic diversity of people of Sikkim, a central Himalayan state of India with different migrant mongoloid groups, assume great significance in understanding the impact of migratory events in the genetic differentiation of populations. We therefore studied the genetic diversity on the basis of 13-tetra nucleotide and 2 penta nucleotide microsatellite loci for a total of 208 allele frequencies in three major populations of Sikkim, with different ethno history and time of settlement.     

The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study

Background  

Obesity causes or exacerbates a host of medical conditions, including cardiovascular, pulmonary, and endocrine diseases. Recently obesity in elderly women was associated with greater risk of dementia, white matter ischemic changes, and greater brain atrophy. The purpose of this study was to determine whether body type affects global brain volume, a marker of atrophy, in middle-aged men and women.     

Development of a diagnostic system for Burkholderia pseudomallei infections

Monoclonal antibodies were generated against whole cell lysate of Burkholderia pseudomallei. Two out of 6 monoclonal antibodies were found specific and exhibited high affinity against B. pseudomallei, one of which, was utilized to develop sandwich ELISA for detection of specific B. pseudomallei antigen. Immunoassays were found to be specific as no reaction was observed with closely related Burkholderia and Pseudomonas species. Blood samples from experimentally infected mice were found positive for isolation till 4 days post infection (DPI) and ELISA till 10 DPI. One out of 40 sick animal serum samples tested in Thailand was found positive by sandwich ELISA that was earlier confirmed by isolation of B. pseudomallei. The results indicate the potentiality of the assay for its applicability in specific diagnosis of septicaemic melioidosis.