Phylogenies of atpD and recA support the small subunit rRNA-based classification of rhizobia

The current classification of the rhizobia (root-nodule symbionts) assigns them to six genera. It is strongly influenced by the small subunit (16S, SSU) rRNA molecular phylogeny, but such single-gene phylogenies may not reflect the evolution of the genome as a whole. To test this, parts of the atpD and recA genes have been sequenced for 25 type strains within the alpha -Proteobacteria, representing species in Rhizobium, Sinorhizobium, Mesorhizobium, Bradyrhizobium, Azorhizobium, Agrobacterium, Phyllobacterium, Mycoplana and Brevundimonas. The current genera Sinorhizobium and Mesorhizobium are well supported by these genes, each forming a distinct phylogenetic clade with unequivocal bootstrap support. There is good support for a Rhizobium clade that includes Agrobacterium tumefaciens, and the very close relationship between Agrobacterium rhizogenes and Rhizobium tropici is confirmed. There is evidence for recombination within the genera Mesorhizobium and Sinorhizobium, but the congruence of the phylogenies at higher levels indicates that the genera are genetically isolated. rRNA provides a reliable distinction between genera, but genetic relationships within a genus may be disturbed by recombination

Recent, independent and anthropogenic origins of Trypanosoma cruzi hybrids.

The single celled eukaryote Trypanosoma cruzi, a parasite transmitted by numerous species of triatomine bug in the Americas, causes Chagas disease in humans. T. cruzi generally reproduces asexually and appears to have a clonal population structure. However, two of the six major circulating genetic lineages, TcV and TcVI, are TcII-TcIII inter-lineage hybrids that are frequently isolated from humans in regions where chronic Chagas disease is particularly severe. Nevertheless, a prevalent view is that hybridisation events in T. cruzi were evolutionarily ancient and that active recombination is of little epidemiological importance. We analysed genotypes of hybrid and non-hybrid T. cruzi strains for markers representing three distinct evolutionary rates: nuclear GPI sequences (n = 88), mitochondrial COII-ND1 sequences (n = 107) and 28 polymorphic microsatellite loci (n = 35). Using Maximum Likelihood and Bayesian phylogenetic approaches we dated key evolutionary events in the T. cruzi clade including the emergence of hybrid lineages TcV and TcVI, which we estimated to have occurred within the last 60,000 years. We also found evidence for recent genetic exchange between TcIII and TcIV and between TcI and TcIV. These findings show that evolution of novel recombinants remains a potential epidemiological risk. The clearly distinguishable microsatellite genotypes of TcV and TcVI were highly heterozygous and displayed minimal intra-lineage diversity indicative of even earlier origins than sequence-based estimates. Natural hybrid genotypes resembled typical meiotic F1 progeny, however, evidence for mitochondrial introgression, absence of haploid forms and previous experimental crosses indicate that sexual reproduction in T. cruzi may involve alternatives to canonical meiosis. Overall, the data support two independent hybridisation events between TcII and TcIII and a recent, rapid spread of the hybrid progeny in domestic transmission cycles concomitant with, or as a result of, disruption of natural transmission cycles by human activities

W Boson Inclusive Decays to Quarkonium at the LHC

In this paper, the production rates of quarkonia eta_c, J/psi, eta_b, Upsilon, B_c and B_c^* through W boson decay at the LHC are calculated, at the leading order in both the QCD coupling constant and in v, the typical velocity of the heavy quark inside of mesons. It shows that a sizable number of quarkonia from W boson decay will be produced at the LHC. Comparison with the predictions by using quark fragmentation mechanism is also discussed. Results show that, for the charmonium production through W decay, the difference between predictions by the fragmentation mechanism and complete leading order calculation is around 3%, and it is insensitive to the uncertainties of theoretical parameters; however, for the bottomonium and B_c^(*) productions, the difference cannot be ignored as the fragmentation mechanism is less applicable here due to the relatively large ratio mb/mw.Comment: Updated to match the published version in EPJ

Cohort Profile: Pregnancy And Childhood Epigenetics (PACE) Consortium.

Development Psychopathology in context: famil

The epidemiology of louping ill virus and flavivirus evolution

SIGLEAvailable from British Library Document Supply Centre-DSC:D197167 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Genotype of galectin 2 (LGALS2) is associated with insulin-glucose profile in the British Women’s Heart and Health Study

AIMS/HYPOTHESIS: It has been suggested that the gene encoding lymphotoxin-alpha (LTA) is associated with insulin resistance, and genetic association studies in the LTA region offer some support for this. However, LTA is in linkage disequilibrium with both the HLA gene cluster and the gene encoding TNF-alpha, making inferences about causality difficult. In this study, we used the galectin 2 (LGALS2) genotype, which affects LTA secretion but is located on another chromosome than the HLA gene cluster or TNF, to examine the relationship between the LTA pathway and traits of the metabolic syndrome. SUBJECTS: A cross-sectional genetic association study was carried out in 3,272 British women of European origin who were aged 60 to 79 years and were randomly selected from the community. RESULTS: Fasting plasma glucose and serum insulin were statistically significantly associated with LGALS2 rs7291467, with this association being independent of BMI and WHR. The mean difference in fasting insulin per minor allele was -4% (p=0.01 for trend by allele) and the mean per minor allele difference in fasting glucose was -2% (p=0.02 for trend by allele). When women with known diabetes were excluded from the analyses the findings did not differ from those for the whole cohort. CONCLUSIONS/INTERPRETATION: Our findings for the physically unlinked LGALS2, invite further study of LGALS2 specifically and the LTA pathway generally for their influence on glucose-insulin regulation