Multi-element uptake and growth responses of Rice (Oryza sativa L.) to TiO2 nanoparticles applied in different textured soils.

The aim of present work was to evaluate the effects of titanium dioxide nanoparticles (TiO2 NPs) on rice's growth (Oryza sativa L.) and nutrient availability under different soil textures. Greenhouse experiment was carried out with three soil textures (sandy loam, silt loam and silty clay loam) and two concentrations of TiO2 NPs (500, 750 mg kg-1). Control (without TiO2 NPs) was also maintained for the comparison. Growth parameters including chlorophyll content, root/shoot length, fresh/dry biomass and nutrients' uptake including calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorous (P), potassium (K) and zinc (Zn) were determined. The results revealed that application of 500 mg kg-1 TiO2 NPs in silty clay loam soil increased the chlorophyll content (3.3-folds), root length (49%), shoot length (31%), root and shoot biomass (41% & 39%, respectively) as compared to other soil textures. The maximum plant growth was observed in silty clay loam > silt loam > sandy loam. Concentration of Cu, Fe, P and Zn in shoot was increased by 8 - , 2.3 - , 0.4 - , 0.05 -folds in silty clay loam upon 500 mg kg-1 TiO2 NPs application as compared to the control. Backward selection method to model the parameters (nutrients in soil) for the response variables (root/shoot length and biomass) showed that Ca, Fe, P are the main nutrients responsible for the increase in plant length and biomass. Overall, the growth of rice was better in silty clay loam at 500 mg kg-1 of TiO2 NPs.

TiO2 nanoparticles dose, application method and phosphorous levels influence genotoxicity in Rice (Oryza sativa L.), soil enzymatic activities and plant growth.

The present study focused on investigating the effect of titanium dioxide nanoparticles (TiO2NPs) on rice (Oryza sativa L.) growth and changes in soil health in two contrasting soil textures (silt-loam and clay). Moreover, response of rice to different methods of TiO2NPs application and phosphorous fertilizer levels were also evaluated. For toxicity assessment, pot experiment was carried out. TiO2NPs (0, 500, 750 mg kg-1) were applied and plants were grown till vegetative stage. After harvesting, physiological parameters, stress assay, soil microbial and enzymatic activities were determined. Based on the results of toxicity study, impact of three methods of TiO2NPs application (foliar, irrigation, soil) and four phosphorous fertilizer levels (0, 10, 20, 40 mg kg-1) on rice growth were assessed. During the 1st phase, results showed an adverse effect of TiO2NPs on plant growth and soil microorganisms in both soil textures at 750 mg kg-1. The H2O2 production, lipid peroxidation and leaf membrane injury index were increased by 4.3-, 2.4-, and 1.9-folds in clay soil upon 750 mg kg-1 TiO2NPs application. Likewise, at the same level of TiO2NPs; microbial biomass, dehydrogenase, and respiration were decreased by 0.91-, 0.79-, and 0.78- folds respectively. In 2nd phase, maximum shoot length, biomass, phosphorous uptake and rice grain protein content were observed under application of TiO2NPs (500 mg kg-1) through irrigation method in combination with 40 mg P kg-1. However, 20 and 40 mg P kg-1 performed equally well upon TiO2NPs application and the results were not statistically significant. The results suggest that 750 mg kg-1 of TiO2NPs negatively affect plant growth and soil enzymatic activities. Moreover, combined application of TiO2NPs (500 mg kg-1) through irrigation and 20 mg P kg-1 is recommended to be the optimum for growth of rice plant.

Field evaluation of a blood based test for active tuberculosis in endemic settings.

Over 9 million new active tuberculosis (TB) cases emerge each year from an enormous pool of 2 billion individuals latently infected with Mycobacterium tuberculosis (M. tb.) worldwide. About 3 million new TB cases per year are unaccounted for, and 1.5 million die. TB, however, is generally curable if diagnosed correctly and in a timely manner. The current diagnostic methods for TB, including state-of-the-art molecular tests, have failed in delivering the capacity needed in endemic countries to curtail this ongoing pandemic. Efficient, cost effective and scalable diagnostic approaches are critically needed. We report a multiplex TB serology panel using microbead suspension array containing a combination of 11 M.tb. antigens that demonstrated overall sensitivity of 91% in serum/plasma samples from TB patients confirmed by culture. Group wise sensitivities for sputum smear positive and negative patients were 95%, and 88%, respectively. Specificity of the test was 96% in untreated COPD patients and 91% in general healthy population. The sensitivity of this test is superior to that of the frontline sputum smear test with a comparable specificity (30-70%, and 93-99%, respectively). The multiplex serology test can be performed with scalability from 1 to 360 patients per day, and is amenable to automation for higher (1000s per day) throughput, thus enabling a scalable clinical work flow model for TB endemic countries. Taken together, the above results suggest that well defined antibody profiles in blood, analyzed by an appropriate technology platform, offer a valuable approach to TB diagnostics in endemic countries.