In phylogenetic reconstruction, two types of bacterial tyrosyl-tRNA synthetases (TyrRS) form distinct clades with many bacterial phyla represented in both clades. Very few taxa possess both forms, and maximum likelihood analysis of the distribution of TyrRS types suggests horizontal gene transfer (HGT), rather than an ancient duplication followed by differential gene loss, as the contributor to...

Total mercury (HgT) and monomethylmercury (MMHg) were investigated in a tropical head watershed (1 km(2)) of French Guiana. The watershed includes a pristine area on the hill slopes and a former gold mined flat in the bottomland. Concentrations of dissolved and particulate HgT and MMHg were measured in rain, throughfall, soil water and at three points along the stream. Samples were taken in-bet...

Horizontal gene transfer (HGT) can have profound effects on bacterial evolution by allowing individuals to rapidly acquire adaptive traits that shape their strategies for competition. One strategy for intermicrobial antagonism often used by Proteobacteria is the genetically encoded contact-dependent type VI secretion system (T6SS), a weapon used to kill heteroclonal neighbors by direct injectio...

In this study we introduce two novel distance-based algorithms with provably high computational and statistical efficiency. Furthermore, we report the results of experiments simulating sequence evolution on large trees with 135, 500, and 1895 leaves showing high success rates of our algorithms for large mutation probabilities, and high success rates of the popular Neighbor-Joining algorithm for...

â â â  this paper attempts to investigate the relationship between 500hpa circulation patterns and weather types (coldest, warmest and raining) over 16 synoptic stations of mountainous region of iran. the mountainous region of iran covers about 670000 square kilometer (41 percent) of iran. in this paper have been investigated the relationship between circulation patterns in 500hpa level with we...

The central Arctic Ocean remains largely unexplored when it comes to the presence and cycling of mercury its methylated forms including mono- dimethylmercury (MMeHg DMeHg, respectively). In this study, we quantified total Hg (HgT) species in seawater, ice cores, snow, brine, water from melt ponds collected during SWEDARCTIC 2016 expedition Amerasian Eurasian side Lomonosov Ridge. column, concen...

The issue of nitrate contamination has become increasingly acute, with the awareness their toxicity on human body and identification increasing sources contamination. Human intervention in natural nitrogen cycle serious repercussions that are manifested by its accumulation at one or more levels. use fertilizers agriculture is crucial to ensure food security, but unreasonable causes accumulation...

As the Human Genome Project and other genome projects experience remarkable success and a flood of biological data is produced by means of high-throughout sequencing techniques, detection of horizontal gene transfer (HGT) becomes a promising field in bioinformatics. This review describes two freeware programs: T-REX for MS Windows and RHOM for Linux. TREX is a graphical user interface program t...

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a human pathogen that colonizes the skin or throat, and causes a range of diseases from relatively benign pharyngitis to potentially fatal invasive diseases. While not as virulent as the close relative Streptococcus pyogenes the two share a number of virulence factors and are known to coexist in a human host. Both pre- and post-genomic stu...