DGR mutagenic transposition occurs via hypermutagenic reverse transcription primed by nicked template RNA.

Diversity-generating retroelements (DGRs) are molecular evolution machines that facilitate microbial adaptation to environmental changes. Hypervariation occurs via a mutagenic retrotransposition process from a template repeat (TR) to a variable repeat (VR) that results in adenine-to-random nucleotide conversions. Here we show that reverse transcription of the Bordetella phage DGR is primed by an adenine residue in TR RNA and is dependent on the DGR-encoded reverse transcriptase (bRT) and accessory variability determinant (Avd ), but is VR-independent. We also find that the catalytic center of bRT plays an essential role in site-specific cleavage of TR RNA for cDNA priming. Adenine-specific mutagenesis occurs during reverse transcription and does not involve dUTP incorporation, indicating it results from bRT-catalyzed misincorporation of standard deoxyribonucleotides. In vivo assays show that this hybrid RNA-cDNA molecule is required for mutagenic transposition, revealing a unique mechanism of DNA hypervariation for microbial adaptation

Analysis of risk factors, maternal and fetal outcome of spontaneous preterm premature rupture of membranes: a cross sectional study

Background: Preterm premature rupture of membranes (PPROM) is one of the most common complications of pregnancy. It is an important cause of perinatal morbidity and mortality. Objective of present study was to determine incidence, risk factors, maternal, fetal outcome of PPROM occurring in patients attending a tertiary hospital in North Eastern India.Methods: This descriptive cross- sectional study was carried out in the department of Obstetrics and Gynecology, Regional Institute of Medical Sciences, Imphal, India. Out of 15,969 deliveries between July 2010 to December 2011, 358 pregnant patients with spontaneous preterm premature rupture of membranes from 28-0 to 36-6weeks gestation were reviewed. After excluding patients with uterine anomalies, intrauterine deaths and congenital anomalies 293 patients were included and evaluated in this study.Results: The incidence of PPROM was 2.2%. Out of 293 patients 86% were singleton pregnancies, 12.9% were twins and 1.02% were triplets. 48.4% had previous history of termination of pregnancy, 28.6% history of previous PPROM and 16.3% had urinary tract infection. The mean gestational age at the onset of membrane rupture was 34.1+2.4 weeks and the latency from the membrane rupture to delivery interval ranged from 0-72 days with a mean of 48.4 hours. There were 7stillbirths (2.38%) and 4 neonatal deaths (1.02%) resulting in perinatal deaths of 3.29% and perinatal mortality rate of 0.329 per 1000 births due to PPROM. Maternal morbidity was minimal with postpartum haemorrhage in 11 patients (4.1%), abruptio placentae in 7 patients (2.3%) and sepsis in 43patients (14.6%). 66 patients (22.5%) underwent caesarean section for which malpresentations were the major cause.Conclusions: Despite remarkable advances in perinatal care, preterm premature rupture of membranes continues to cause perinatal morbidity and mortality. Strategies should be developed for its prevention. Management protocol should be improved in regard to vaginal swab culture and use of specific antibiotics

Serum malondialdehyde and serum glutathione peroxidase levels in pregnant women with and without preeclampsia

Background: Preeclampsia is a pregnancy-specific disorder that affects 10% of all pregnancies which contributes heavily to maternal mortality and perinatal morbidity. Several studies have shown that oxidative stress plays an important role in the pathogenesis of preeclampsia. However, the association has not been proven indisputably. So, the study was done with the view to determine serum malondialdehyde and glutathione peroxidase levels in pregnant women with and without preeclampsia and to compare the levels between the two groups of participants. Methods: This is a cross-sectional study conducted in the Department of Biochemistry and Department of Obstetrics and Gynaecology, RIMS. 55 preeclamptic patients and 55 pregnant women without preeclampsia were recruited as cases and controls respectively. Results: Serum malondialdehyde was found to be significantly higher in cases (1280.02±619.55ng/ml) than the controls (826.51±599.84ng/ml) and glutathione peroxidase levels were found to be significantly decreased in the preeclamptic women (224.49±201.29pg/ml) when compared to the normal healthy pregnant women (448±350.54 pg/ml. Serum malondialdehyde levels were found to be positively correlated with blood pressure. Conclusions: Serum malondialdehyde was increased in preeclampsia and serum glutathione levels was decreased in preeclamptic pregnant women when compared to the pregnant women without preeclampsia. Serum malondialdehyde levels were significantly correlated with high blood pressure. The oxidant-antioxidant system may be involved in the etiology of preeclampsia, however the cause and effect relation needs further evaluation

Not Available

Not AvailableTo feed around 9.8 billion people by 2050, it is equally important to increase food production while maintaining the sustainability of the environment. Conservation agriculture (CA) is one of the approaches to manage agro-ecosystems in order to improve productivity, increase the profitability and food security and enhance the resource base and environment. Although many researchers have pointed out the prospects and concerns of adopting CA in different climatic conditions, CA in arid regions raises uncertainties due to its extreme climates, most of the soils with low water holding capacity, high potential evapotranspiration, low and non-uniform distribution of rainfall and greater wind erosion. However, CA practices could benefit the arid agriculture through moderation/reducing of evaporation, regulating water and nutrient in soil and reducing wind erosion. Arid soils, largely characterised by low soil organic carbon (SOC), have the greater potential for higher C sequestration with the use of CA practices. Among the key components of CA, no-tillage (NT) coupled with mulching might be effective in distribution of the soil moisture at proper stage of the crop growth. The emission of CO2 flux from soil and soil salinity are reduced with the adoption of CA in arid soils with the use of cover crops. Due to better aeration and nutrient movement in CA land, beneficial bacterial community and diversity are promoted. However, for CA to work effectively in arid regions, the three components of CA such as minimum disturbances of soil through no- and reduced-tillage, permanent soil cover and crop rotation must be critically followed together or simultaneously for improving soil health, crop productivity through high nutrient and water efficiency, carbon sequestration, mitigation of climate change and sustainability.Not Availabl

Jal Upoyog Kshamta Jal Sangrahani Ek Chavi

Not AvailableNot AvailableNot Availabl

Not Available

In the food production sector, soil degradation due to soil salinization and sodification has become one of the universal concerns agriculture is facing. According to Food and Agriculture Organization (FAO) of the United Nations, around the world nearly one billion hectares of soil were facing severe levels of salinization and sodification problem that need immediate attention (FAO, 1994). The problem of soil salinity and sodicity also leads to desertification (Tóth et al., 2008). In addition to chemical inorganic amendments like gypsum, organic amendments are studied for their efficiency in reclaiming soil sodicity as addition of organic matter to soil improves soil health through various beneficial functions, thus helping in effective reclamation (Roy et al., 2006). Therefore, this study was conducted in order to investigate the utilisation of economical organic amendments as sources of soil sodicity reclamation in comparison with gypsum.An incubation study was conducted at AICRP laboratory, ADAC&RI, Trichy to assess the efficiency of different amendments in reclaiming soil sodicity. Sodic soil samples were treated with different amendments such as inorganic source (gypsum) and organic amendments (vermicompost, green manure, goat manure, poultry manure, coir pith compost and FYM) and at weekly intervals, the physico-chemical properties related with sodicity of the treated soils were analysed. It was found that gypsum was effective in reducing soil sodicity. However, organic amendment such as vermicompost was at par with gypsum in reclamation of soil sodicity.Not Availabl

The Bordetella bacteriophage DGR employs similar mechanisms for retrotransposition in heterologous species

Diversity-generating retroelements (DGRs) are a unique group of retroelements found in bacteria, archaea and their viruses. They mediate hyperdiversification of protein-encoding DNA sequences in facilitate the adaptation of their hosts to changing environments. The prototype DGR was discovered in the Bordetella bacteriophage BPP-1 and consists of three genes, mtd (major tropism determinant), avd (accessory variability determinant) and brt (Bordetella reverse transcriptase), and two imperfect repeats, variable repeat (VR) and template repeat (TR). VR is located at the 3' end of mtd, which encodes the phage distal tail fiber protein responsible for receptor recognition. Diversification of mtd results from unidirectional transfer of sequence information from TR to VR during which adenine residues in TR are converted into random nucleotides in VR, leading to phage tropic variants that recognize different receptor molecules. Here, we show that the BPP-1 DGR is also functional in heterologous bacterial species - Escherichia coli and Pseudomonas aeruginosa, and uses a similar mechanism for cDNA synthesis. However, efficiency of DGR mutagenic homing is affected by target sequence orientation in plasmids. Interestingly, overexpression of Avd and bRT has differential effects on DGR homing into targets inserted in different vectors. Surprisingly, homing into plasmid targets in E. coli is found to be largely independent of IMH (initiation of mutagenic homing) and the DNA stem-loop, elements important for its homing into native phage targets.Santa S. Naorem, Jin Han, Christa Jackson, Bingyue Zhang, James Guo and Huatao Guo ; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri 6521

Not Available

Not AvailableNot AvailableNot Availabl