Co-inoculation of native multi-trait plant growth promoting rhizobacteria promotes plant growth and suppresses Alternaria blight disease in castor (Ricinus communis L.).

Background: Castor (Ricinus communis L.) is cultivated for seed oil and to feed (leaves) Eri silkworm, Samia ricini (Donovan) Hutt. Alternaria blight affects castor cultivation resulting substantial yield loss (∼30%). Uses of synthetic fertilizers and agrochemicals for disease management have serious concerns as the castor leaves are fed to eri silkworms for rearing. Application of plant growth promoting rhizobacteria for disease suppression and to enhance plant growth will be a healthier choice in castor cultivation. The aim of this study was to assess the efficacy of Alternaria blight disease suppression by native rhizobacteria isolated from wasteland castor and their ability on plant growth promotion. Methodology: We isolated 50 bacterial antagonists from castor rhizosphere using the dilution plate method and evaluated their antagonistic activity against the castor blight pathogen, Alternaria ricini. Based on antimicrobial bioassay and plant growth promotion (PGP) traits (phosphate solubilization, ACC deaminase activities, production of IAA, GA3, HCN, NH3 and siderophore), salt and acid tolerance; we have chosen ten potential isolates and identified them through 16SrRNA gene sequencing and analysis. Disease suppression and plant growth studies were evaluated in pot experiments. Results and conclusion: Three isolates namely, Enterobacter hormaechei (LRP-2), Bacillus mycoides (HF-1) and B. aryabhattai (UR-6) showed potential antagonistic activities and PGP traits which were selected for disease suppression and PGP studies. Application of PGPR consortia (LRP-2+HF-1) could suppress the plants from A. ricini infection in challenged inoculation. Mix inoculation of LRP-2 and UR-6 showed synergistic effect and enhanced plant growth in pot experiments. Combinations of E. hormaechei (LRP-2), B. mycoides (HF-1) and B. aryabhattai (UR-6) can be applied as bio-control and bio-fertilizer formulation to protect castor from Alternaria blight and also to enhance plant growth.

Assessment of under nutrition among under 5 tribal children in a rural area in West Bengal.

Tribal population is socio economically disadvantaged group. Knowledge about nutritional status of various tribal populations is important because it impels to identify under nutrition which is a leading cause of morbidity and mortality. This study is conducted to assess under nutrition among under 5 tribal children. In this cross sectional study with a sample of 68 under 5 tribal children selected through complete enumeration fulfilling the inclusion criteria after obtaining ethical clearance from Institutional Ethics Committee. Anthropometric measurements were recorded to determine types of under nutrition prevailing among them using World Health Organization Anthro software. 24 h recall of dietary history of children was taken for 7 days to assess mean energy, protein, and fat intake per day and compared with recommended daily allowances. A total of 30.8% children were stunted, 30.8% were wasted, and 14.7% were both stunted and wasted. The consumption of energy, protein, and fat was much low. Chi square test showed a significant association of under nutrition with gender, education of father, type of family, socio economic status, and birth order but binary logistic regression showed significant association only with socioeconomic status. Under nutrition in form of stunting and wasting and low dietary intake of energy, protein, fat was found among these children. Multi sectoral approach is suggested.

A role for Vibrio vulnificus PecS during hypoxia.

The genus Vibrio includes serious human pathogens, and mollusks are a significant reservoir for species such as V. vulnificus. Vibrio species encode PecS, a member of the multiple antibiotic resistance regulator (MarR) family of transcription factors; pecS is divergently oriented to pecM, which encodes an efflux pump. We report here that Vibrio species feature frequent duplications of pecS-pecM genes, suggesting evolutionary pressures to respond to distinct environmental situations. The single V. vulnificus PecS binds two sites within the pecS-pecM intergenic region with Kd = 0.3 ± 0.1 nM, a binding that is attenuated by the ligands xanthine and urate, except when promoter DNA is saturated with PecS. A unique target is found in the intergenic region between genes encoding the nitric oxide sensing transcription factor, NsrR, and nod; the nod-encoded nitric oxide dioxygenase is important for preventing nitric oxide stress. Reporter gene assays show that PecS-mediated repression of gene expression can be relieved in presence of ligand. Since xanthine and urate are produced as part of the oxidative burst during host defenses and under molluscan hypoxia, we propose that these intermediates in the host purine degradation pathway function to promote bacterial survival during hypoxia and oxidative stress.

An Aspartate-Specific Solute-Binding Protein Regulates Protein Kinase G Activity To Control Glutamate Metabolism in Mycobacteria.

Signaling by serine/threonine phosphorylation controls diverse processes in bacteria, and identification of the stimuli that activate protein kinases is an outstanding question in the field. Recently, we showed that nutrients stimulate phosphorylation of the protein kinase G substrate GarA in Mycobacterium smegmatis and Mycobacterium tuberculosis and that the action of GarA in regulating central metabolism depends upon whether it is phosphorylated. Here we present an investigation into the mechanism by which nutrients activate PknG. Two unknown genes were identified as co-conserved and co-expressed with PknG: their products were a putative lipoprotein, GlnH, and putative transmembrane protein, GlnX. Using a genetic approach, we showed that the membrane protein GlnX is functionally linked to PknG. Furthermore, we determined that the ligand specificity of GlnH matches the amino acids that stimulate GarA phosphorylation. We determined the structure of GlnH in complex with different amino acid ligands (aspartate, glutamate, and asparagine), revealing the structural basis of ligand specificity. We propose that the amino acid concentration in the periplasm is sensed by GlnH and that protein-protein interaction allows transmission of this information across the membrane via GlnX to activate PknG. This sensory system would allow regulation of nutrient utilization in response to changes in nutrient availability. The sensor, signaling, and effector proteins are conserved throughout the Actinobacteria, including the important human pathogen Mycobacterium tuberculosis, industrial amino acid producer Corynebacterium glutamicum, and antibiotic-producing Streptomyces species.IMPORTANCE Tuberculosis (TB) kills 5,000 people every day, and the prevalence of multidrug-resistant TB is increasing in every country. The processes by which the pathogen Mycobacterium tuberculosis senses and responds to changes in its environment are attractive targets for drug development. Bacterial metabolism differs dramatically between growing and dormant cells, and these changes are known to be important in pathogenesis of TB. Here, we used genetic and biochemical approaches to identify proteins that allow M. tuberculosis to detect amino acids in its surroundings so that it can regulate its metabolism. We have also shown how individual amino acids are recognized. The findings have broader significance for other actinobacterial pathogens, such as nontuberculous mycobacteria, as well as Actinobacteria used to produce billions of dollars of amino acids and antibiotics every year.

An intervention study on compliance of diabetes mellitus patients.

The effect of intervention (counselling) on compliance was observed in 106 diabetes mellitus patients with poor glycaemic control attending a clinic. They were selected at random and the period of study extended over 3 months. Intervention (counselling) improved significantly their compliance with advices on diet, exercise and drug as well as their glycaemic status.