Progress and prospects of C4 trait engineering in plants.

Incorporating C4 photosynthetic traits into C3 crops is a rational approach for sustaining future demands for crop productivity. Using classical plant breeding, engineering this complex trait is unlikely to achieve its target. Therefore, it is critical and timely to implement novel biotechnological crop improvement strategies to accomplish this goal. However, a fundamental understanding of C3 , C4 , and C3 -C4 intermediate metabolism is crucial for the targeted use of biotechnological tools. This review assesses recent progress towards engineering C4 photosynthetic traits in C3 crops. We also discuss lessons learned from successes and failures of recent genetic engineering attempts in C3 crops, highlighting the pros and cons of using rice as a model plant for short-, medium- and long-term goals of genetic engineering. This review provides an integrated approach towards engineering improved photosynthetic efficiency in C3 crops for sustaining food, fibre and fuel production around the globe.

Novel Trichoderma strains isolated from tree barks as potential biocontrol agents and biofertilizers for direct seeded rice.

This study is the first time report of utilization of Trichoderma spp. isolated from different tree bark from Odisha state of India for rice crop health management and higher productivity. Six isolates of Trichoderma spp. were identified based on the morphological characteristics and species determination was performed by molecular assays. One of the isolated strains determined as Trichoderma erinaceum outperformed others. Trichoderma erinaceum controlled three soil borne plant pathogens i.e. Rhizoctonia solani, Sclerotium rolfsii and Sclerotium oryzae effectively under controlled condition and R. solani and Helminthosporium oryzae under filed condition. Seed treatments with the formulated isolates improved the germination rate of rice and enhanced vigour. These parameters along with higher chlorophyll content could be related to higher yield observed in two rice varieties; Karuna and Sahabhagidhan. Among the six isolates tested, Trichoderma erinaceum treatment recorded highest yield. Significantly higher expression of some stress related enzymes was observed in Trichoderma treated plants which helped in better crop growth both under biotic and abiotic stresses. These isolates helped both the varieties to accumulate more nutrients. This study proves that Trichoderma erinaceum obtained from tree bark may be incorporated in integrated rice crop management both as biocontrol agent and biofertilizer.

HGSNAT has a TATA-less promoter with multiple starts of transcription.

Acetyl-CoA:α-glucosaminide N-acetyltransferase (N-acetyltransferase) is a lysosomal membrane enzyme that catalyzes a key step in the lysosomal degradation of heparan sulfate. Its deficiency causes Sanfilippo syndrome type IIIC (Mucopolysaccharidosis type IIIC, MPS IIIC). Here we characterize the promoter region of HGSNAT, the gene encoding N-acetyltransferase, which is located in the pericentromeric region of chromosome 8. We show that HGSNAT transcription is driven by a TATA-less promoter whose key elements are contained within the 1054bp region upstream of exon 1. About 400 bases of the region's 3'-prime end overlap with an unmethylated CpG island. Reduced reporter activities from promoter serial deletion constructs suggested strong regulatory elements at positions -101 to -20bp and -1073 to -716bp of the downstream initiation codon (DS-ATG). Targeted mutagenesis of the first Specificity protein 1-A (Sp1-A) of the six in silico-predicted Sp1 sites in the region flanking the major transcription start sites (TSSs, +50/-101) led to a 55% decrease of reporter activity, while inactivation of each of Sp1-B and Sp1-C resulted in its almost two-fold increase. The binding of Sp1 to the region was confirmed by chromatin immunoprecipitation (ChIP). Overall, this confirms that Sp1 is important for regulation of the HGSNAT promoter. Promoter fragments in antisense orientation (constructs pGL4 -20/-1305 and pGL4 +50/-1305) led to reporter activities of about 50% of the pGL4 -1305/-20 activity, implying divergent initiation of transcription at the promoter. We identified two main TSSs at positions +1 and -15 from DS-ATG using Rapid amplification of cDNA ends (5'RACE). Transcripts initiating at the TSSs thus contain only DS-ATG. Five patients from our MPS IIIC cohort (n=23) carried the rs4523300 promoter variant and one the rs149596192 promoter variant. Both variants lowered the expression of the reporter down to 68% and 59%, respectively. However, white blood cell (WBC) N-acetyltransferase activities in individuals carrying the variants did not significantly differ from homozygotes for the wild-type alleles, suggesting only a partial impact of transcriptional regulation on N-acetyltransferase activities in vivo.

Activation of Ras overcomes B-cell tolerance to promote differentiation of autoreactive B cells and production of autoantibodies.

Newly generated immature B cells are selected to enter the peripheral mature B-cell pool only if they do not bind (or bind limited amount of) self-antigen. We previously suggested that this selection relies on basal extracellular signal-regulated kinase (Erk) activation mediated by tonic B-cell antigen receptor (BCR) signaling and that this signal can be replaced by an active rat sarcoma (Ras), which are small GTPase proteins. In this study we compared the activity of Ras and Erk in nonautoreactive and autoreactive immature B cells and investigated whether activation of Ras can break tolerance. Our results demonstrate lower levels of active Erk and Ras in autoreactive immature B cells, although this is evident only when these cells display medium/high avidity for self-antigen. Basal activation of Erk in immature B cells is proportional to surface IgM and dependent on sarcoma family kinases, whereas it is independent of B-cell activating factor, IFN, and Toll-like receptor signaling. Ectopic expression of the constitutively active mutant Ras form N-RasD12 in autoreactive cells raises active Erk, halts receptor editing via PI3 kinase, and promotes differentiation via Erk, breaking central tolerance. Moreover, when B cells coexpress autoreactive and nonautoreactive BCRs, N-RasD12 leads also to a break in peripheral tolerance with the production of autoantibodies. Our findings indicate that in immature B cells, basal activation of Ras and Erk are controlled by tonic BCR signaling, and that positive changes in Ras activity can lead to a break in both central and peripheral B-cell tolerance.

Why youth smoke? An exploratory community-based study from Chandigarh Union Territory of northern India.

BACKGROUND: Tobacco use is a serious public health challenge in several regions of the world, including India. Increasingly, steps are being taken at policy level to curb the problem. AIM: This study was done to find out the determinants of tobacco use so that effective intervention programs can be designed and implemented for the prevention and cessation of this growing pandemic. METHODS: A community-based cross-sectional study was done adapting Global Youth Tobacco Survey questionnaire prepared by the Centre for Disease Control, Atlanta, among youth (15-24 years). Patterns of smoking and their determinants were calculated using univariate and multivariate analyses. RESULTS: Prevalence of current smoking among youth was 20.4% (95% confidence interval: 16.9-23.9%). Male sex, smoking peers, cigarette advertisements, and feeling comfortable in social gatherings were significant determinants for smoking after adjusting for all explanatory variables. CONCLUSION: Strict enforcement of regulations pertaining to cigarette advertisements in any form, enabling environment and community interventions focusing on parents and peers are required for effective control of tobacco problem among youth in India.

In silico characterization and homology modeling of thylakoid-bound ascorbate peroxidase from a drought tolerant wheat cultivar.

Ascorbate peroxidase, a haem protein (EC 1.11.1.11), efficiently scavenges hydrogen peroxide (H(2)O(2)) in cytosol and chloroplasts of plants. In this study, a full-length coding sequence of thylakoid-bound ascorbate peroxidase cDNA (TatAPX) was cloned from a drought tolerant wheat cultivar C306. Homology modeling of the TatAPX protein was performed by using the template crystal structure of chloroplastic ascorbate peroxidase from tobacco plant (PDB: 1IYN). The model structure was further refined by molecular mechanics and dynamic methods using various tools such as PROCHECK, ProSA and Verify3D. The predicted model was then tested for docking with H(2)O(2), the substrate for TatAPX enzyme. The results revealed that Arg233 and Glu255 in the predicted active site of the enzyme are two important amino acid residues responsible for strong hydrogen bonding affinity with H(2)O(2), which might play an important role in scavenging of H(2)O(2) from the plant system.

Preparations and limitations for prevention of severe acute respiratory syndrome in a tertiary care centre of India.

This short-term observational study of infection control practice was performed in the medical emergency outpatient department (EMOPD) of a tertiary-care hospital in India when threatened by an outbreak of severe acute respiratory syndrome (SARS). An investigator attended the lobby daily to screen patients with symptoms for SARS. Patient/attendant load, patient flow, medical staff working practices and position in the EMOPD were observed. Infection control measures such as fumigation and cleaning were noted, as was the EMOPD laboratory function, use of personnel protection and display of information on infectious diseases. A total of 162 (7.4%) of the 2165 patients surveyed had respiratory symptoms but no cases of SARS were found. The flow of patients and their attendants was not systematic. No laboratory tests for SARS were available, and no educational material on SARS was displayed. The EMOPDs in key hospitals need be able to screen for infectious diseases, especially in view of the threats from SARS and Avian influenza.