Use of RAPD in assessing the genetic variability in Spodoptera litura

A polymerase chain reaction based assay to distinguish six different ecotypes of the Spodoptera litura, a sporadic insect pest and a predominant defoliator of various crops was carried out. A total of 40 random primers were screened to reveal the existence of polymorphism between the populations. Among them eight showed scorable banding patterns and three primers (OPA-01, OPA-05, OPM-01) exhibited distinguishable banding patterns. However, Chengalpattu and Chennai populations revealed their closed relatedness and Coimbatore population stood distantly from others.     

The genome sequence of the anaerobic, sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough

Desulfovibrio vulgaris Hildenborough is a model organism for studying the energy metabolism of sulfate-reducing bacteria (SRB) and for understanding the economic impacts of SRB, including biocorrosion of metal infrastructure and bioremediation of toxic metal ions. The 3,570,858 base pair (bp) genome sequence reveals a network of novel c-type cytochromes, connecting multiple periplasmic hydrogenases and formate dehydrogenases, as a key feature of its energy metabolism. The relative arrangement of genes encoding enzymes for energy transduction, together with inferred cellular location of the enzymes, provides a basis for proposing an expansion to the 'hydrogen-cycling' model for increasing energy efficiency in this bacterium. Plasmid-encoded functions include modification of cell surface components, nitrogen fixation and a type-III protein secretion system. This genome sequence represents a substantial step toward the elucidation of pathways for reduction (and bioremediation) of pollutants such as uranium and chromium and offers a new starting point for defining this organism's complex anaerobic respiration.     

Genetic polymorphism of six DNA loci in six population groups of India

The genetic profile based on autosomal markers, four microsatellite DNA markers (D8S315, FES, D8S592, and D2S1328) and two minisatellite DNA markers (TPMT and PDGFA), were analyzed in six endogamous populations to examine the effect of geographic and linguistic affiliation on the genetic affinities among the groups. The six populations are from three different states of India and are linguistically different. Marathas from western India speak Marathi, an Indo-European language. Arayas, Muslims, Ezhavas, and Nairs from Kerala state of South India speak Malayalam, and Iyers from Tamil Nadu state speak Tamil. Genomic DNA was extracted from peripheral blood samples of random, normal, healthy individuals. Locus-specific PCR amplification was carried out, followed by electrophoresis of the amplicons and genotyping. All the loci were highly polymorphic and followed Hardy-Weinberg equilibrium, except for loci D8S315 and PDGFA in Iyers and Marathas, respectively. All six loci had high heterozygosity (average heterozygosity ranged from 0.73 to 0.76) and high polymorphism information content (0.57-0.90). The extent of gene differentiation among the six populations (G(ST) = 0.030) was greater than that for four Kerala populations (G(ST) = 0.011), suggesting proximity between the four Kerala populations. This result conforms with the cultural and linguistic background of the populations. The extent of diversity found among the populations probably resulted from the strict endogamous practices that they follow.     

Nickel-binding and accessory proteins facilitating Ni-enzyme maturation in Helicobacter pylori

Helicobacter pylori colonizes the human gastric mucosa and this can lead to chronic gastritis, peptic and duodenal ulcers, and even gastric cancers. The bacterium colonizes over one-half of the worlds population. Nickel plays a major role in the bacteriums colonization and persistence attributes as two nickel enzyme sinks obligately contain the metal. Urease accounts for up to 10% of the total cellular protein made and is required for initial colonization processes, and the hydrogen oxidizing hydrogenase provides the bacterium a high-energy substrate yielding low potential electrons for energy generation. A battery of accessory proteins are needed for maturation or activation of each of the apoenzymes. These include Ni-chaperones and GTPases, some of which are unique to each Ni-enzyme and others that are individually required for maturation of both the Ni-enzymes. H. pylori’s need for some conventional hydrogenase maturation proteins playing roles in urease maturation may have to do with the poor nickel-sequestering ability of the UreE urease maturation protein compared to other systems. H. pylori also possesses a NixA nickel specific permease, a nickel dependent regulator (NikR), a recently identified nickel efflux system (CznABC), and a histidine-rich heat shock protein, HspA. Based on mutant analysis approaches all these proteins have roles in nickel homeostasis, in urease expression, and in host colonization. The His-rich putative nickel storage proteins Hpn and Hpn-like play roles in nickel detoxification and may influence the levels of Ni-activated urease that can be achieved.