Metabolite Profiling Reveals Abiotic Stress Tolerance in Tn5 Mutant of Pseudomonas putida

Pseudomonas is an efficient plant growth-promoting rhizobacteria (PGPR); however, intolerance to drought and high temperature limit its application in agriculture as a bioinoculant. Transposon 5 (Tn5) mutagenesis was used to generate a stress tolerant mutant from a PGPR Pseudomonas putida NBRI1108 isolated from chickpea rhizosphere. A mutant NBRI1108T, selected after screening of nearly 10,000 transconjugants, exhibited significant tolerance towards high temperature and drought. Southern hybridization analysis of EcoRI and XhoI restricted genomic DNA of NBRI1108T confirmed that it had a single Tn5 insertion. The metabolic changes in the polar and non-polar extracts of NBRI1108 and NBRI1108T were examined using 1H, 31P nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Thirty six chemically diverse metabolites consisting of amino acids, fatty acids and phospholipids were identified and quantified. Insertion of Tn5 influenced amino acid and phospholipid metabolism and resulted in significantly higher concentration of aspartic acid, glutamic acid, glycinebetaine, glycerophosphatidylcholine (GPC) and putrescine in NBRI1108T as compared to that in NBRI1108. The concentration of glutamic acid, glycinebetaine and GPC increased by 34%, 95% and 100%, respectively in the NBRI1108T as compared to that in NBRI1108. High concentration of glycerophosphatidylethanolamine (GPE) and undetected GPC in NBRI1108 indicates that biosynthesis of GPE may have taken place via the methylation pathway of phospholipid biosynthesis. However, high GPC and low GPE concentration in NBRI1108T suggest that methylation pathway and phosphatidylcholine synthase (PCS) pathway of phospholipid biosynthesis are being followed in the NBRI1108T. Application of multivariate principal component analysis (PCA) on the quantified metabolites revealed clear variations in NBRI1108 and NBRI1108T in polar and non-polar metabolites. Identification of abiotic stress tolerant metabolites from the NBRI1108T suggest that Tn5 mutagenesis enhanced tolerance towards high temperature and drought. Tolerance to drought was further confirmed in greenhouse experiments with maize as host plant, where NBRI1108T showed relatively high biomass under drought conditions

High Prevalence of Human T-Lymphotropic Virus Infection in Indigenous Women from the Peruvian Amazon

BACKGROUND: In an earlier study, we detected an association between human T-cell lymphotropic virus (HTLV) infection and cervical human papillomavirus (HPV) in indigenous Amazonian Peruvian women of the Shipibo-Konibo ethnic group. As both HTLV and HPV can be transmitted sexually, we now report a population-based study examining the prevalence and risk factors for HTLV-1 and HTLV-2 infection in this population. METHODS: Between July and December 2010, we conducted a comprehensive screening for HTLV among Shipibo-Konibo women 15 to 39 years of age living in two communities located in Lima and in 17 communities located within four hours by car or boat from the Amazonian city of Pucallpa in Peru. RESULTS: We screened 1,253 Shipibo-Konibo women for HTLV infection 74 (5.9%) tested positive for HTLV-1, 47 (3.8%) for HTLV-2 infection, and 4 (0.3%) had indeterminate results. In the multivariate analysis, factors associated with HTLV-1 infection included: older age (Prevalence Ratio (PR): 1.04, 95% CI 1.00–1.08), primary education or less (PR: 2.01, 95% CI: 1.25–3.24), younger or same age most recent sex partner (PR: 1.66, 95% CI: 1.00–2.74), and having a most recent sex partner who worked at a logging camp (PR: 1.73, 95% CI: 1.09–2.75). The only factor associated with HTLV-2 infection was older age (PR: 1.08, 95% CI: 1.03–1.12). CONCLUSION: HTLV infection is endemic among Shipibo-Konibo women. Two characteristics of the sexual partner (younger age and labor history) were associated with infection in women. These results suggest the need for implementation of both HTLV screening during the antenatal healthcare visits of Shipibo-Konibo women, and counseling about the risk of HTLV transmission through prolonged breastfeeding in infected women. We also recommend the implementation of prevention programs to reduce sexual transmission of these viruses