A highly supported maximum-likelihood species phylogeny for the genus Bradyrhizobium was inferred from a supermatrix obtained from the concatenation of partial atpD, recA, glnII, and rpoB sequences corresponding to 33 reference strains and 76 bradyrhizobia isolated from the nodules of Glycine max (soybean) trap plants inoculated with soil samples from Myanmar, India, Nepal, and Vietnam. The power of the multigene approach using multiple strains per species was evaluated in terms of overall tree resolution and phylogenetic congruence, representing a practical and portable option for bacterial molecular systematics. Potential pitfalls of the approach are highlighted. Seventy-five of the isolates could be classified as B. japonicum type Ia (USDA110/ USDA122-like), B. liaoningense, B. yuanmingense, or B. elkanii, whereas one represented a novel Bradyrhizobium lineage. Most Nepalese B. japonicum Ia isolates belong to a highly epidemic clone closely related to strain USDA110. Significant phylogenetic evidence against the monophyly of the of B. japonicum I and Ia lineages was found. Analysis of their DNA polymorphisms revealed high population distances, significant genetic differentiation, and contrasting population genetic structures, suggesting that the strains in the Ia lineage are misclassified as B. japonicum. The DNA polymorphism patterns of all species conformed to the expectations of the neutral mutation and population equilibrium models and, excluding the B. japonicum Ia lineage, were consistent with intermediate recombination levels. All species displayed epidemic clones and had broad geographic and environmental distribution ranges, as revealed by mapping climate types and geographic origins of the isolates on the species tree.Soybean (Glycine max) is the most important grain legume in the world, with an annual production of around 180 million tons and a market value of more than 36 billion euros. This crop is planted on 5.7 million, 8.3 million, 29 million, and 30 million hectares in India, China, South America, and North America, respectively (66). It is a major cash crop for small farmers in Asia, in South America, and also in some African countries. The diversity of soybeans today is the result of more than 5,000 years of cultivation, which started in China, where more than 20,000 land races were selected and later globally distributed and further domesticated by modern breeding programs (4). Soybeans were introduced in India around 1000 CE via the silk route from China (26).Bradyrhizobium japonicum, Bradyrhizobium elkanii, Bradyrhizobium liaoningense, Ensifer (Sinorhizobium) fredii, Ensifer xinjiangense, and Mesorhizobium tianshanense are the microsymbionts currently known to nodulate soybeans naturally under field conditions (19,23,36,45,46,57,68). Soybean-nodulating B. japonicum strains have been isolated from different continents and climatic zones. Recently, two B. japonicum biovars (symbiotic ecotypes) were described (61). The B. japonicum bv. glycinearum isolates nodulate soybeans, whereas the B. ...
Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide and affects both health status and productivity. However, no studies have examined the distribution of BLV in Myanmar, and the genetic characteristics of Myanmar BLV strains are unknown. Therefore, the aim of this study was to detect BLV infection in Myanmar and examine genetic variability. Blood samples were obtained from 66 cattle from different farms in four townships of the Nay Pyi Taw Union Territory of central Myanmar. BLV provirus was detected by nested PCR and real-time PCR targeting BLV long terminal repeats. Results were confirmed by nested PCR targeting the BLV env-gp51 gene and real-time PCR targeting the BLV tax gene. Out of 66 samples, six (9.1 %) were positive for BLV provirus. A phylogenetic tree, constructed using five distinct partial and complete env-gp51 sequences from BLV strains isolated from three different townships, indicated that Myanmar strains were genotype-10. A phylogenetic tree constructed from whole genome sequences obtained by sequencing cloned, overlapping PCR products from two Myanmar strains confirmed the existence of genotype-10 in Myanmar. Comparative analysis of complete genome sequences identified genotype-10-specific amino acid substitutions in both structural and non-structural genes, thereby distinguishing genotype-10 strains from other known genotypes. This study provides information regarding BLV infection levels in Myanmar and confirms that genotype-10 is circulating in Myanmar.
Background Respiratory hazards are common in the workplace. Depending on the hazard and exposure, the health consequences may include: mild to life-threatening illnesses from infectious agents, acute e ects ranging from respiratory irritation to chronic lung conditions, or even cancer from exposure to chemicals or toxins. Use of respiratory protective equipment (RPE) is an important preventive measure in many occupational settings. RPE only o ers protection when worn properly, when removed safely and when it is either replaced or maintained regularly. The e ectiveness of behavioural interventions either directed at employers or organisations or directed at individual workers to promote RPE use in workers remains an important unanswered question. Objectives To assess the e ects of any behavioural intervention either directed at organisations or at individual workers on observed or self-reported RPE use in workers when compared to no intervention or an alternative intervention. Behavioural interventions to promote workers' use of respiratory protective equipment (Review)
Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide and causes serious problems for the cattle industry. In this study, we examined the prevalence of BLV infection and the distribution of BLV genotypes in cattle in the northern, central, and southern parts of Myanmar. The prevalence of BLV infection among Myanmar cattle (37.04%) in this study was markedly higher than the prevalence (9.1%) observed in our earlier study in which BLV was detected from the limited number of cattle only from a small area of Myanmar. Phylogenetic analysis of partial env-gp51 sequence of the isolated BLV strains revealed that there are at least three BLV genotypes (genotype-1, genotype-6, and genotype-10) in Myanmar, which have also been detected in the neighboring countries. We performed this study to estimate the BLV proviral load, which is a major diagnosis index for determining the virus transmission risk. The cattle of the three test regions with warm, wet, and humid climatic conditions (upper Sagaing, Yangon, and Kayin) exhibited a high mean proviral load, while cattle of three other regions with low annual rainfall and very high temperature (Mandalay, Magway, and upper Bago) exhibited a low mean proviral load. Further, the level of proviral load and the prevalence of BLV infection in Myanmar native cattle (N = 235) were lower than that in the hybrid cattle (Holstein Friesian × Myanmar native) (N = 62). We also observed that the cattle with high risk for BLV transmission, which have high proviral load, may enhance the BLV infection rate. Hence, to control BLV transmission, it is necessary to eliminate these cattle with high-risk for BLV transmission and to diagnose BLV provirus in cattle in the remaining regions/states of Myanmar sharing a boundary with neighboring countries.
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