Showing papers by "Jawaharlal Nehru University published in 2013"

Strategies for the Production of Recombinant Protein in Escherichia coli

Abstract: In the recent past years, a large number of proteins have been expressed in Escherichia coli with high productivity due to rapid development of genetic engineering technologies. There are many hosts used for the production of recombinant protein but the preferred choice is E. coli due to its easier culture, short life cycle, well-known genetics, and easy genetic manipulation. We often face a problem in the expression of foreign genes in E. coli. Soluble recombinant protein is a prerequisite for structural, functional and biochemical studies of a protein. Researchers often face problems producing soluble recombinant proteins for over-expression, mainly the expression and solubility of heterologous proteins. There is no universal strategy to solve these problems but there are a few methods that can improve the level of expression, non-expression, or less expression of the gene of interest in E. coli. This review addresses these issues properly. Five levels of strategies can be used to increase the expression and solubility of over-expressed protein; (1) changing the vector, (2) changing the host, (3) changing the culture parameters of the recombinant host strain, (4) co-expression of other genes and (5) changing the gene sequences, which may help increase expression and the proper folding of desired protein. Here we present the resources available for the expression of a gene in E. coli to get a substantial amount of good quality recombinant protein. The resources include different strains of E. coli, different E. coli expression vectors, different physical and chemical agents and the co expression of chaperone interacting proteins. Perhaps it would be the solutions to such problems that will finally lead to the maturity of the application of recombinant proteins. The proposed solutions to such problems will finally lead to the maturity of the application of recombinant proteins.

Crystal structure of a eukaryotic phosphate transporter

Abstract: The X-ray crystal structure of a high-affinity phosphate importer in an inward-facing, occluded state in the presence of phosphate is reported; this is the first structure of a membrane protein involved in inorganic phosphate uptake and the first crystal structure of a eukaryotic MFS transporter. Proton/phosphate symporters of the major facilitator superfamily (MFS) are key to the uptake of inorganic phosphate in fungi and plants. This manuscript reports the X-ray crystal structure of a fungal high-affinity phosphate importer, PiPT, in an inward-facing, 'occluded' state in the presence of phosphate. The structure explains the mechanism for phosphate affinity and specificity, and connects the proton-motive force to phosphate translocation. PiPT also provides a useful model for key transporters whose malfunctions in humans are associated with diseases such as cancer and diabetes, as well as those that mediate drug metabolism. Phosphate is crucial for structural and metabolic needs, including nucleotide and lipid synthesis, signalling and chemical energy storage. Proton-coupled transporters of the major facilitator superfamily (MFS) are essential for phosphate uptake in plants and fungi, and also have a function in sensing external phosphate levels as transceptors1,2,3,4,5. Here we report the 2.9 A structure of a fungal (Piriformospora indica) high-affinity phosphate transporter, PiPT, in an inward-facing occluded state, with bound phosphate visible in the membrane-buried binding site. The structure indicates both proton and phosphate exit pathways and suggests a modified asymmetrical ‘rocker-switch’ mechanism of phosphate transport. PiPT is related to several human transporter families, most notably the organic cation and anion transporters of the solute carrier family (SLC22), which are implicated in cancer-drug resistance6,7. We modelled representative cation and anion SLC22 transporters based on the PiPT structure to surmise the structural basis for substrate binding and charge selectivity in this important family. The PiPT structure demonstrates and expands on principles of substrate transport by the MFS transporters and illuminates principles of phosphate uptake in particular.

Graphene oxide-chitosan nanocomposite based electrochemical DNA biosensor for detection of typhoid

Abstract: Graphene oxide (GO)-Chitosan (CHI) nano-composite is employed for the development of DNA based electrochemical biosensor for diagnosis of typhoid. Biosensor has been prepared by covalent immobilization of Salmonella typhi specific 5′-amine labeled single stranded (ss) DNA probe on GO-CHI/ITO via glutaraldehyde. Differential pulse voltammetry (DPV) studies revealed good specificity and ability of ssDNA/GO-CHI/ITO biosensor to distinguish complementary, non-complementary and one base mismatch sequences. The ssDNA/GO-CHI/ITO biosensor showed detection range of 10 fM to 50 nM and LOD 10 fM within 60 s hybridization times for complementary sequence. Further, ssDNA/GO-CHI/ITO bioelectrode is able to detect complementary target present in serum samples with LOD of 100 fM at 25 °C. The excellent performance of biosensor is attributed to large surface-to-volume ratio and good electrochemical activity of graphene oxide, and good biocompatibility of chitosan, which enhances the DNA immobilization and facilitate electron transfer between DNA and electrode surface (ITO).

Fluctuations in butyrate-producing bacteria in ulcerative colitis patients of North India

Abstract: AIM: To study the interplay between butyrate concentration and butyrate-producing bacteria in fecal samples of ulcerative colitis (UC) patients vs control individuals.

Balanced conditions or slight mass gain of glaciers in the Lahaul and Spiti region (northern India, Himalaya) during the nineties preceded recent mass loss

Abstract: . The volume change of the Chhota Shigri Glacier (India, 32° 20 N, 77° 30' E) between 1988 and 2010 has been determined using in situ geodetic measurements. This glacier has experienced only a slight mass loss between 1988 and 2010 (−3.8 ± 2.0 m w.e. (water equivalent) corresponding to −0.17 ± 0.09 m w.e. yr−1). Using satellite digital elevation models (DEM) differencing and field measurements, we measure a negative mass balance (MB) between 1999 and 2010 (−4.8 ± 1.8 m w.e. corresponding to −0.44 ± 0.16 m w.e. yr−1). Thus, we deduce a slightly positive or near-zero MB between 1988 and 1999 (+1.0 ± 2.7 m w.e. corresponding to +0.09 ± 0.24 m w.e. yr−1). Furthermore, satellite DEM differencing reveals that the MB of the Chhota Shigri Glacier (−0.39 ± 0.15 m w.e. yr−1) has been only slightly less negative than the MB of a 2110 km2 glaciarized area in the Lahaul and Spiti region (−0.44 ± 0.09 m w.e. yr−1) during 1999−2011. Hence, we conclude that the ice wastage is probably moderate in this region over the last 22 yr, with near equilibrium conditions during the nineties, and an ice mass loss after. The turning point from balanced to negative mass budget is not known but lies probably in the late nineties and at the latest in 1999. This positive or near-zero MB for Chhota Shigri Glacier (and probably for the surrounding glaciers of the Lahaul and Spiti region) during at least part of the 1990s contrasts with a recent compilation of MB data in the Himalayan range that indicated ice wastage since 1975. However, in agreement with this compilation, we confirm more negative balances since the beginning of the 21st century.

Cyclophilins: Proteins in search of function

Abstract: Cyclophilins constitute a subgroup of large family of proteins called immunophilins, which also include FKBPs and Parvulins. They are remarkably conserved in all genera, highlighting their pivotal role in important cellular processes. Most cyclophilins display PPIase enzymatic activity, multiplicity, diverse cellular locations and active role in protein folding which render them to be included in the class of diverse set of proteins called molecular chaperones. Due to their distinct PPIase function, besides protein disulfide isomerases and protein foldases, cyclophilins have been deemed necessary for in vivo chaperoning activity. Unlike other cellular chaperones, these proteins are specific in their respective targets. Not all cyclophilin proteins possess PPIase activity, indicating a loss of their PPIase activity during the course of evolution and gain of function independent of their PPIase activity. The PPIase function of cyclophilins is also compensated by their functional homologs, like FKBPs. Multiple cyclophilin members in plants like Arabidopsis and rice have been reported to be associated with diverse functions and regulatory pathways through their foldase, scaffolding, chaperoning or other unknown activities. Although many functions of plant cyclophilins were reported or suggested, the physiological relevance and molecular basis of stress-responsive expression of plant cyclophilins is still largely unknown. However, their wide distribution and ubiquitous nature signifies their fundamental importance in plant survival. Several of these members have also been directly linked to multiple stresses. This review attempts to deal with plant cyclophilins with respect to their role in stress response.

Piriformospora indica rescues growth diminution of rice seedlings during high salt stress.

Abstract: Piriformospora indica association has been reported to increase biotic as well as abiotic stress tolerance of its host plants. We analyzed the beneficial effect of P. indica association on rice seedlings during high salt stress conditions (200 and 300 mM NaCl). The growth parameters of rice seedlings such as root and shoot lengths or fresh and dry weights were found to be enhanced in P. indica-inoculated rice seedlings as compared with non-inoculated control seedlings, irrespective of whether they are exposed to salt stress or not. However, salt-stressed seedlings performed much better in the presence of the fungus compared with non-inoculated control seedlings. The photosynthetic pigment content [chlorophyll (Chl) a, Chl b, and carotenoids] was significantly higher in P. indica-inoculated rice seedlings under high salt stress conditions as compared with salt-treated non-inoculated rice seedlings, in which these pigments were found to be decreased. Proline accumulation was also observed during P. indica colonization, which may help the inoculated plants to become salt tolerant. Taken together, P. indica rescues growth diminution of rice seedlings under salt stress.

Morphometric analysis of Morar River Basin, Madhya Pradesh, India, using remote sensing and GIS techniques

Abstract: Hydrogeological mapping and drainage analysis can form an important tool for groundwater development. Assessment of drainage and their relative parameters have been quantitatively carried out for the Morar River Basin, which has made positive scientific contribution for the local people of area for the sustainable water resource development and management. Geographical Information System has been used for the calculation and delineation of the morphometric characteristics of the basin. The dendritic type drainage network of the basin exhibits the homogeneity in texture and lack of structural control. The stream order ranges from first to sixth order. The drainage density in the area has been found to be low which indicates that the area possesses highly permeable soils and low relief. The bifurcation ratio varies from 2.00 to 5.50 and the elongation ratio (0.327) reveals that the basin belongs to the elongated shaped basin category. The results of this analysis would be useful in determining the effect of catchment characteristics such as size, shape, slope of the catchment and distribution of stream net work within the catchment.

An Advanced DV-Hop Localization Algorithm for Wireless Sensor Networks

Abstract: In emerging sensor network applications, localization in wireless sensor network is a recent area of research. Requirement of its applications and availability of resources need feasible localization algorithm with lower cost and higher accuracy. In this paper, we propose an Advanced DV-Hop localization algorithm that reduces the localization error without requiring additional hardware and computational costs. The proposed algorithm uses the hop-size of the anchor (which knows its location) node, from which unknown node measures the distance. In the third step of Advanced DV-Hop algorithm, inherent error in the estimated distance between anchor and unknown node is reduced. To improve the localization accuracy, we use weighted least square algorithm. Furthermore, location of unknown nodes is refined by using extraneous information obtained by solving the equations. By mathematical analysis, we prove that Advanced DV-Hop algorithm has lesser correction factor in the distance between anchor and the unknown node compared with DV-Hop algorithm, improved DV-Hop algorithm (Chen et al. 2008) and improved DV-Hop algorithm (Chen et al. in IEICE Trans Fundam E91-A(8), 2008), which is cause of better location accuracy. Simulation results show that the performance of our proposed algorithm is superior to DV-Hop algorithm and improved DV-Hop algorithms in all considered scenarios.

Biosorption of arsenite (As+3) and arsenate (As+5) from aqueous solution by Arthrobacter sp. biomass

Abstract: In this study we investigated the role of arsenic-resistant bacteria Arthrobacter sp. biomass for removal of arsenite as well as arsenate from aqueous solution. The biomass sorption characteristics were studied as a function of biomass dose, contact time and pH. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm. The Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of the biomass for As+3 and As+5 was found to be 74.91 mg/g (pH 7.0) and 81.63 mg/g (pH 3.0), respectively using 1 g/L biomass with a contact time of 30 min at 28°C. The mean sorption energy values calculated from the D-R model indicated that the biosorption of As+3 and As+5 onto Arthrobacter sp. biomass took place by chemical ion-exchange. The thermodynamic parameters showed that the biosorption of As+3 and As+5 ions onto Arthrobacter sp. biomass was feasible, spontaneous and exothermic in nature. Kinetic evaluation of experimental...

Study of cloudburst and flash floods around Leh, India, during August 4–6, 2010

Abstract: Leh and surrounding region of the Ladakh mountain range in the trans-Himalaya experienced multiple cloudbursts and associated flash floods during August 4–6, 2010. However, 12.8 mm/day rainfall recorded at the nearest meteorological station at Leh did not corroborate with the flood severity. For better understanding of this event, hydrological analysis and atmospheric modeling are carried out in tandem. Two small catchments (<3 km2) were studied along the stream continuum to assess the flood characteristics to identify the cloudburst impact zones. Peak flood discharges were estimated close to the head wall region and at the catchment outlet of the Leh town and the Sabu eastern tributary catchments. Storm runoff depth is estimated by developing a triangular hydrograph by using the known time base of the flood hydrograph. This triangular hydrographs have been transformed further into storm hydrographs to gain a better understanding of the storm duration by using the dimensionless hydrograph method at selected cross sections. Storm duration is estimated by using the relationship between time to peak and time of concentration of the catchment. The peak flood estimates ranged from 122(±35 %) m3/s for Leh town catchment (2.393 km2), 545(±35 %) m3/s for Sabu eastern tributary catchment (2.831 km2) to 1,070(±35 %) m3/sec for Sabu catchment (64.95 km2). To assess the atmospheric processes associated with this event, a triple nest simulation (27, 9 and 3 km) is performed using Advanced Research Weather Research and Forecasting (WRF) modeling system. The simulation does show the evolution of the event from August 4 to 6, 2010. Observation constraints, orographic responses, etc. make such analysis complex at such scale. Independent estimate by the atmospheric process model and the hydrological method shows the storm depth of 70 mm and 91.8(±35 %) mm, respectively, in catchment scale. Hydrological evaluation further refined the spatial and temporal extents of the cloudbursts in the respective catchments with an estimated storm depth of 209(±35 %) mm in 11.9 min and 320(±35 %) in 8.8 min occurring in an area of 0.842–1.601 km2, respectively. This study shows that the insight developed on the cloudburst phenomena by the atmospheric and the hydrological modeling is hugely constrained by the spatial and temporal scales of data used for the analysis. Apart from this, study also highlighted the regular occurrence of cloudburst events over this region in the recent past. Most of such events go unreported due to lack of monitoring mechanisms in the region and weaken our ability to understand these events in complete perspective.

Biophysical insight into furosemide binding to human serum albumin: a study to unveil its impaired albumin binding in uremia.

Abstract: Exogenous substances like drugs, when absorbed, enter into the circulatory system and bind reversibly and extensively to human serum albumin (HSA). But transport of various drugs like a diuretic, furosemide (FUR), via albumin in uremia is seriously compromised due to accumulation of uremic toxins. The reason behind it is explored by investigating the binding mechanism of FUR to HSA. Isothermal titration calorimetry results show that FUR binds with HSA at high (Kb ∼ 104) and low affinity (Kb ∼ 103) sites whereas spectroscopic results predict binding at a single site (Kb ∼ 105). Thermodynamic analysis shows that the HSA-FUR complex formation occurs via hydrogen bonds and hydrophobic interactions and undergoes slight structural changes, as evident by FTIR and far-UV CD. Further, the lifetime of HSA decreases only marginally and thus the magnitude of energy transfer efficiency is small, as obtained by time-resolved measurements. A displacement experiment predicts that the FUR binds mainly to site I but a new ...

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

Abstract: [1] We present the climatology of aerosol microphysics, its trends, and impact of potential sources based on the long term measurements (for a period of 11.5 years from December 2001 to May 2012) of aerosol optical depths (AOD) in the spectral range 340–1020 nm from an urban center Delhi (28.6°N, 77.3°E, 238 m mean sea level) in the western Indo-Gangetic Plain (IGP). The study is the first ever long-term characterization of aerosols over the western IGP from the ground-based measurements. AODs are known to affect the air quality, visibility, radiative balance, and cloud microphysics of the region and IGP is one of the highest populated and polluted regions of the world. Our measurements show consistently high AOD during the entire period of observation. The seasonal variations of spectral AODs and Angstrom parameters are generally consistent every year. The AODs show a weak but statistically significant (in 95% confidence level) decreasing trend approximately −0.02/year at 500 nm, possibly, modulated by the pre-monsoon heavy dust loading during the first half of the observation period. The climatological monthly mean AOD at shorter wavelengths peaks twice, during June and November, while at longer wavelengths it shows only one peak in June. The annual variations of Angstrom exponent, α and its derivative, α′ suggest the prevalence of multi-modal aerosol size distributions at Delhi. The coarse-mode aerosols dominate during summer (March–June) and monsoon (July–September) seasons, whereas fine/accumulation mode enhances during post-monsoon (October–November) and winter (December–February) seasons. Potential advection pathways have been identified using concentration weighted trajectory (CWT) analysis of the 5 day isentropic air mass back trajectories at the observation site and their seasonal variations are discussed.

Future of wetlands in tropical and subtropical Asia, especially in the face of climate change

Abstract: Tropical and subtropical Asia differs from other tropical regions in its monsoonal climate and the dominant influence of the Hindukush and Himalayan mountain ranges which result in extremes of spatial and temporal variability in precipitation. However, several major rivers and their tributaries arise in the Himalayan ranges and are fed by thousands of glaciers. Huge sediment loads carried by these rivers result in important deltas at their mouths. The climatic and physiographic diversity have endowed the region with many kinds of wetlands. Of these, the peatswamps of southeast Asia constitute about 56% of the world’s tropical peatlands, and more than 42% of the world’s mangroves occur in South and southeast Asia. Among other wetlands, riverine swamps are rather restricted whereas the seasonal marshes are a dominant feature. Another characteristic feature of tropical Asia are the innumerable human-made and intensively managed wetlands of which the paddy fields and aquaculture ponds are the most extensive. Throughout tropical Asia, wetlands have been a part of the socio-cultural ethos of the people and many communities have lived in wetlands. However, the pressures of high population and the economic development have extensively impacted upon wetlands which have been transformed for paddy cultivation and aquaculture, drained and converted to other land uses for economic gains (e.g., conversion to oil palm), and degraded by discharge of domestic and industrial wastes. Invasive plant and animal species have also played a significant role. The climate change is already being felt in the rapid retreat of Himalayan glaciers, increased temperature and variability in precipitation as well as the frequency of extreme events. Sea level rise is seen as a major threat to the coastal wetlands, particularly the mangroves. Increasing droughts have caused frequent fires in Indonesian peat swamps that have further feedback impacts on regional climate. However, the actual threat to wetlands in this region arises from the extensive hydrological alterations being caused by storage, abstraction and diversion of river flows for agriculture, industry and hydropower. Currently, the state of our understanding wetlands in general, and the efforts and infrastructure for research and training in wetlands are very poor. Although a few wetlands have been designated as Ramsar sites, the policies aimed at wetland conservation are either non-existent or very weak. Human responses to greater uncertainty and variability in the available water resources in different parts of Asia will be crucial to the conservation of wetlands in the future.

Performance evaluation of data aggregation for cluster-based wireless sensor network

Abstract: In wireless sensor network, data fusion is considered an essential process for preserving sensor energy. Periodic data sampling leads to enormous collection of raw facts, the transmission of which would rapidly deplete the sensor power. In this paper, we have performed data aggregation on the basis of entropy of the sensors. The entropy is computed from the proposed local and global probability models. The models provide assistance in extracting high precision data from the sensor nodes. We have also proposed an energy efficient method for clustering the nodes in the network. Initially, sensors sensing the same category of data are placed within a distinct cluster. The remaining unclustered sensors estimate their divergence with respect to the clustered neighbors and ultimately join the least-divergent cluster. The overall performance of our proposed methods is evaluated using NS-2 simulator in terms of convergence rate, aggregation cycles, average packet drops, transmission cost and network lifetime. Finally, the simulation results establish the validity and efficiency of our approach.

Modeling adsorption kinetics of trichloroethylene onto biochars derived from soybean stover and peanut shell wastes

Abstract: Trichloroethylene (TCE) is one of the most hazardous organic pollutants in groundwater. Biochar produced from agricultural waste materials could serve as a novel carbonaceous adsorbent for removing organic contaminants from aqueous media. Biochars derived from pyrolysis of soybean stover at 300 °C and 700 °C (S-300 and S-700, respectively), and peanut shells at 300 °C and 700 °C (P-300 and P-700, respectively) were utilized as carbonaceous adsorbents to study batch aqueous TCE remediation kinetics. Different rate-based and diffusion-based kinetic models were adopted to understand the TCE adsorption mechanism on biochars. With an equilibrium time of 8–10 h, up to 69 % TCE was removed from water. Biochars produced at 700 °C were more effective than those produced at 300 °C. The P-700 and S-700 had lower molar H/C and O/C versus P-300 and S-300 resulting in high aromaticity and low polarity accompanying with high surface area and high adsorption capacity. The pseudo-second order and intraparticle diffusion models were well fitted to the kinetic data, thereby, indicating that chemisorption and pore diffusion were the dominating mechanisms of TCE adsorption onto biochars.

A collaborative filtering framework for friends recommendation in social networks based on interaction intensity and adaptive user similarity

Abstract: The tremendous growth in the amount of attention and users, on social networking sites (SNSs), has led to information overload and that adds to the difficulty of making accurate recommendations of new friends to the users of SNSs. This article incorporates collaborative filtering (CF), the most successful and widely used filtering technique, in social networks to facilitate users in exploring new friends having similar interests while being connected with old ones as well. Here, first we design an implicit rating model, for estimating a user’s affinity toward his friends, which uncover the strength of relationship, utilizing both attribute similarity and user interaction intensity. We then propose a CF-based framework that offers list of friends to the user by leveraging on the preference of like-minded users, with a given small set of people that user has already labeled as friends. Despite the immense success of CF, accuracy and sparsity are still major challenges, especially in social networking domain with a staggering growth having enormous number of users. To address these inherent challenges, first we have explored the idea of adaptive similarity computation between users by employing evolutionary algorithms to learn individual preferences toward particular set of attributes that results in considerable improvement in recommendation accuracy as compared to the situation where all the attributes are given equal importance. Second, we incorporate effective missing data prediction algorithm as a solution to data sparsity thereby further enhancing accuracy. Experimental results are presented to illustrate the effectiveness of the proposed friends recommendation schemes.

Microfinance and the challenge of financial inclusion for development

Abstract: This article provides a review of the recent literature on microfinance in developing countries and a critical assessment of its effectiveness. It examines the experience of India, which has one of the largest microfinance sectors in the world, and particularly the unfolding of the microfinance crisis in Andhra Pradesh. It concludes that microfinance cannot be seen as a silver bullet for development and that profit-oriented microfinance institutions are problematic. To fulfil even some of its progressive goals, it must be regulated and subsidised, and other strategies for viable financial inclusion of the poor and of small producers must be more actively pursued.

MicroRNA-191, an estrogen-responsive microRNA, functions as an oncogenic regulator in human breast cancer

Abstract: Estrogen- and microRNA-mediated gene regulation play a crucial role in breast cancer biology. However, a functional link between the two major players remains unclear. This study reveals miR-191 as an estrogen-inducible onco-miR in breast cancer, which promotes several hallmarks of cancer including enhanced cell proliferation, migration, chemoresistance and survival in tumor microenvironment. miR-191 is a direct estrogen receptor (ER) target and our results suggest existence of a positive regulatory feedback loop. We show miR-191 as critical mediator of estrogen-mediated cell proliferation. Investigations of mechanistic details of miR-191 functions identify several cancer-related genes like BDNF, CDK6 and SATB1 as miR-191 targets. miR-191 and SATB1 show inverse correlation of expression. miR-191-mediated enhanced cell proliferation and migration are partly dependent on targeted downregulation of SATB1. Further, functional validation of estrogen:miR-191:SATB1 link suggests a cascade initiated by estrogen that induces miR-191 in ER-dependent manner to target SATB1, a global chromatin remodeler, thereby contributing to estrogen-specific gene signature to regulate genes like ANXA1, PIWIL2, CASP4, ESR1/ESR2, PLAC1 and SOCS2 involved in breast cancer progression and migration. Overall, the identification of estrogen/ER/miR-191/SATB1 cascade seems to be a significant pathway in estrogen signaling in breast cancer with miR-191 as oncogenic player.

Modulation of antioxidant machinery in α-tocopherol-enriched transgenic Brassica juncea plants tolerant to abiotic stress conditions.

Abstract: The antioxidant machinery in plants consists of several components with unique or overlapping functions that combat the deleterious production of reactive oxygen species (ROS) induced by stress conditions. Tocopherols are a group of powerful antioxidants having additional roles in signaling and gene expression, with α-tocopherol being the most potent form. In the present study, we used wild-type (WT) and α-tocopherol-enriched transgenic (TR) Brassica juncea plants grown under salt, heavy metal, and osmotic stress to compare their relative tolerance to these stresses and to assess the effects of increased α-tocopherol content on the other antioxidative enzymes and molecules. The oxidative damage caused by induced stress was lower in TR plants compared to WT plants as assessed by their higher relative water content and lower electrolyte leakage, malondialdehyde content as well as H2O2 accumulation. Lesser superoxide and H2O2 accumulation was also observed by histochemical staining in TR seedlings exposed to stress. Though no significant differences were evident under normal growth conditions, TR plants showed higher activities and transcript levels of antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase than WT plants under similar stress conditions. A decrease in ascorbate and glutathione content with marginally higher reductive ratios of these compounds was also observed in TR plants under the stress conditions. Our findings implicate the role of higher α-tocopherol levels in conferring better tolerance against salt, heavy metal, and osmotic stresses and also establish the existence of interplay between this lipid-soluble antioxidant and other water-soluble components of plant antioxidant defense.

A Single-Dose PLGA Encapsulated Protective Antigen Domain 4 Nanoformulation Protects Mice against Bacillus anthracis Spore Challenge

Abstract: Bacillus anthracis, the etiological agent of anthrax, is a major bioterror agent. Vaccination is the most effective prophylactic measure available against anthrax. Currently available anthrax vaccines have issues of the multiple booster dose requirement, adjuvant-associated side effects and stability. Use of biocompatible and biodegradable nanoparticles to deliver the antigens to immune cells could solve the issues associated with anthrax vaccines. We hypothesized that the delivery of a stable immunogenic domain 4 of protective antigen (PAD4) of Bacillus anthracis encapsulated in a poly (lactide-co-glycolide) (PLGA) - an FDA approved biocompatible and biodegradable material, may alleviate the problems of booster dose, adjuvant toxicity and stability associated with anthrax vaccines. We made a PLGA based protective antigen domain 4 nanoparticle (PAD4-NP) formulation using water/oil/water solvent evaporation method. Nanoparticles were characterized for antigen content, morphology, size, polydispersity and zeta potential. The immune correlates and protective efficacy of the nanoparticle formulation was evaluated in Swiss Webster outbred mice. Mice were immunized with single dose of PAD4-NP or recombinant PAD4. The PAD4-NP elicited a robust IgG response with mixed IgG1 and IgG2a subtypes, whereas the control PAD4 immunized mice elicited low IgG response with predominant IgG1 subtype. The PAD4-NP generated mixed Th1/Th2 response, whereas PAD4 elicited predominantly Th2 response. When we compared the efficacy of this single-dose vaccine nanoformulation PAD4-NP with that of the recombinant PAD4 in providing protective immunity against a lethal challenge with Bacillus anthracis spores, the median survival of PAD4-NP immunized mice was 6 days as compared to 1 day for PAD4 immunized mice (p<0.001). Thus, we demonstrate, for the first time, the possibility of the development of a single-dose and adjuvant-free protective antigen based anthrax vaccine in the form of PAD4-NP. Further work in this direction may produce a better and safer candidate anthrax vaccine.

Predicting agricultural drought in eastern Rajasthan of India using NDVI and standardized precipitation index

Abstract: In the present study, prediction of agricultural drought has been addressed through prediction of agricultural yield using a model based on NDVI-SPI. It has been observed that the meteorological drought index SPI with different timescale is correlated with NDVI at different lag. Also NDVI of current fortnight is correlated with NDVI of previous lags. Based on the correlation coefficients, the Multiple Regression Model was developed to predict NDVI. The NDVI of current fortnight was found highly correlated with SPI of previous fortnight in semi-arid and transitional zones. The correlation between NDVI and crop yield was observed highest in first fortnight of August. The RMSE of predicted yield in drought year was found to be about 17.07 kg/ha which was about 6.02 per cent of average yield. In normal year, it was 24 kg/Ha denoting about 2.1 per cent of average yield.

Salt and genotype impact on antioxidative enzymes and lipid peroxidation in two rice cultivars during de-etiolation.

Abstract: Crop yield is severely affected by soil salinity, as salt levels that are harmful to plant growth occur in large terrestrial areas of the world. The present investigation describes the studies of enzymatic activities, in-gel assays, gene expression of some of the major antioxidative enzymes, tocopherol accumulation, lipid peroxidation, ascorbate and dehydroascorbate contents in a salt-sensitive rice genotype PB1, and a relatively salt-tolerant cultivar CSR10 in response to 200 mM NaCl. Salt solution was added to the roots of hydroponically grown 5-day-old etiolated rice seedlings, 12 h prior to transfer to cool white fluorescent + incandescent light (100 μmol photons m−2 s−1). Total tocopherol and ascorbate contents declined in salt-stressed rice seedlings. Among antioxidative enzymes, an increase in the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2), and their gene expression was observed in both cultivars in response to salt stress. The salt-tolerant cultivar CSR10 resisted stress due to its early preparedness to combat oxidative stress via upregulation of gene expression and enzymatic activities of antioxidative enzymes and a higher redox status of the antioxidant ascorbate even in a non-stressed environment.