Preharvest seed infection byAspergillus flavus group fungi and subsequent aflatoxin contamination in groundnuts in relation to soil types

Preharvest seed infection byAspergillus flavus and aflatoxin contamination in selected groundnut genotypes (fourA. flavus-resistant and fourA. flavus-susceptible) were examined in different soil types at several locations in India in 1985–1990. Undamaged mature pods were sampled at harvest and seed examined forA. flavus infection and aflatoxin content in two or more trials at ICRISAT Center on light sandy soils and red sandy loam soils (Alfisols), and on Vertisols, at Anantapur on light sandy soils, and at Dharwad and Parbhani on Vertisols. Rainy season trials (1985–1989) were all rainfed. Post-rainy season trials were irrigated; late-season drought stress (90 days after sowing (DAS) until harvest at 125 DAS) was imposed in the 1987/88 and 1989/90 seasons.A. flavus infection and aflatoxin contamination levels were much lower in seed of all genotypes from Vertisols than in seed from Alfisols across locations and seasons. Vertisols also had significantly lower populations ofA. flavus than Alfisols. There were no marked differences between light sandy soils and red sandy loam soils (Alfisols) in respect of seed infection byA. flavus and aflatoxin contamination. Significant interactions between genotypes and soil types were evident, especially in theA. flavus-susceptible genotypes. Irrespective of soil types,A. flavus-resistant genotypes showed lower levels of seed infection byA. flavus and other fungi than didA. flavus-susceptible genotypes. The significance of the low preharvest aflatoxin risk in groundnuts grown on Vertisols is highlighted.ICRISAT Journal Article No. JA 1122     

Comparative mapping of a gorilla-derived alpha satellite DNA clone on great ape and human chromosomes

We have isolated an alpha satellite DNA clone, pG3.9, from gorilla DNA. Fluorescence in situ hybridization on banded chromosomes under high stringency conditions revealed that pG3.9 identifies homologous sequences at the centromeric region of ten gorilla chromosomes, and, with few exceptions, also recognizes the homologous chromosomes in human. A pG3.9-like alphoid DNA is present on a larger number of orangutan chromosomes, but, in contrast, is present on only tow chromosomes in the chimpanzee. These results show that the chromosomal subsets of related alpha satellite DNA sequences may undergo different patterns of evolution.by J.B. Rattner     

Studies on hemolysis of human erythrocytes by linoleic acid

The results presented in this paper show that lysis of human erythrocytes by linoleic acid is not caused by peroxidation of the fatty acid. Peroxidase, superoxide dismutase and scavengers of O ₂ ⁻ and OH had no effect on the lysis while catalase showed only marginal inhibition suggesting that O ₂ ⁻ , OH, O ₂ ⁻ and H₂O₂ do not play any direct role in hemolysis by linoleic acid. Generators of H₂O₂ inhibited the lysis completely and methemoglobin cells were more resistant to hemolysis by linoleic acid. The fatty acid did neither bind to nor fomed complex with red cell ghosts. Membrane oxidation of sulphydryl groups was also not involved in the lysis. Β-Carotene, retinol and bile salts enhanced the lysis, while, cholesterol but not cholesterol acetate, inhibited it. Taurocholate-pretreated cells were more susceptible to linoleic acid lysis. These observations suggested-that lysis by linoleic acid may be due to its detergent property.     

Understanding the binding interaction between phenyl boronic acid P1 and sugars: determination of association and dissociation constants using S–V plots,steady‐state spectroscopic methods and molecular docking

Continuous monitoring of glucose and sugar sensing plays a vital role in diabetes control. The drawbacks of the present enzyme‐based sugar sensors have encouraged the investigation into alternate approaches to design new sensors. The popularity of fluorescence sensors is due to their ability to bind reversibly to compounds containing diol. In this study we investigated the binding ability of phenyl boronic acid P1 for monosaccharides and disaccharides (sugars) in aqueous medium at physiological pH 7.4 using steady‐state fluorescence and absorbance. P1 fluorescence was quenched due to formation of esters with sugars. Absorbance and fluorescence measurements led to results that indicated that the sugars studied could be ordered in terms of their affinity to P1, as stated: sucrose > lactose > galactose > xylose > ribose > arabinose. In each case, the slope of modified Stern–Volmer plots was nearly 1, indicating the presence of only a single binding site in boronic acids for sugars. Docking studies were carried out using Schrodinger Maestro v.11.2 software. The binding affinity of phenyl boronic acid P1 with periplasmic protein (PDB ID 2IPM and 2IPL) was estimated using GlideScore.     

CDPK1 from Ginger Promotes Salinity and Drought Stress Tolerance without Yield Penalty by Improving Growth and Photosynthesis in Nicotiana tabacum

In plants, transient changes in calcium concentrations of cytosol have been observed during stress conditions like high salt, drought, extreme temperature and mechanical disturbances. Calcium-dependent protein kinases (CDPKs) play important roles in relaying these calcium signatures into downstream effects. In this study, a stress-responsive CDPK gene, ZoCDPK1 was isolated from a stress cDNA generated from ginger using rapid amplification of cDNA ends (RLM-RACE) – PCR technique and characterized its role in stress tolerance. An important aspect seen during the analysis of the deduced protein is a rare coupling between the presence of a nuclear localization sequence in the junction domain and consensus sequence in the EF-hand loops of calmodulin-like domain. ZoCDPK1 is abundantly expressed in rhizome and is rapidly induced by high-salt stress, drought, and jasmonic acid treatment but not by low temperature stress or abscissic acid treatment. The sub-cellular localization of ZoCDPK1-GFP fusion protein was studied in transgenic tobacco epidermal cells using confocal laser scanning microscopy. Over-expression of ginger CDPK1 gene in tobacco conferred tolerance to salinity and drought stress as reflected by the high percentage of seed germination, higher relative water content, expression of stress responsive genes, higher leaf chlorophyll content, increased photosynthetic efficiency and other photosynthetic parameters. In addition, transgenic tobacco subjected to salinity/drought stress exhibited 50% more growth during stress conditions as compared to wild type plant during normal conditions. T3 transgenic plants are able to grow to maturity, flowers early and set viable seeds under continuous salinity or drought stress without yield penalty. The ZoCDPK1 up-regulated the expression levels of stress-related genes RD21A and ERD1 in tobacco plants. These results suggest that ZoCDPK1 functions in the positive regulation of the signaling pathways that are involved in the response to salinity and drought stress in ginger and it is likely operating in a DRE/CRT independent manner.     

Structure and spectral characteristics of diquat-cucurbituril complexes from density functional theory

Electronic structure, ¹H NMR and infrared spectra of diquat (6,7-dihydrodipyrido[1,2-b:1′,2′-e] pyrazine-5,8-diium or DQ²⁺) encapsulated by cucurbit[n]uril (n?=?7,8) hosts are obtained using the density functional theory. Theoretical calculations have shown that both CB[7] or CB[8] host possesses strong affinity toward DQ²⁺ compared to its reduced cation or neutral species. Calculated ¹H NMR spectra reveal that H_α protons on bi-pyridinium rings of DQ²⁺@CB[8] complex are de-shielded owing to C=O?H interactions. On the other hand aromatic (H_β and H_δ) of DQ²⁺ within the CB[8] cavity exhibit significant shielding. The complexation of CB[8] with DQ²⁺ splits the carbonyl stretching vibration (1788 cm^?1) into two distinct vibrations which correspond to 1765 cm^?1 arising from hydrogen bonded carbonyls and the 1792 cm^?1 band from non-interacting ones. Further, the CN stretching vibration in DQ²⁺ exhibits a frequency blue-shift of 6 cm^?1 on its encapsulation within the CB[8] cavity. The direction of frequency shift has been explained on the basis of natural bond orbital analyses.

Computational investigation of the key factors affecting the second stage activation mechanisms of domain II m-calpain

The unique conformation of the active site in calpains along with the implication of their role in several diseases has prompted widespread research interest in the scientific community. Structural studies devoted to m- and μ-calpains have proposed a two-stage calcium-dependent activation mechanism for calpains. In this work, we performed conventional and targeted molecular dynamics simulations to investigate global and local changes in the structure of the protease core of m-calpain upon calcium binding. Simulations were performed on the protease core of calcium free (pdbid: 1kfu) and calcium bound (pdbid: 3df0) m-calpain with and without the presence of calcium ions. Our results indicate that the inactive, open conformation of the protease core does not transform into the active, closed conformation simply upon removal of constraints from the neighbor domains. The role of other factors, including calcium binding and the subsequent formation of an Arg94–Glu305 inter-domain salt bridge and the change in the orientation of Trp288 side chain, in the activation of the protease core is elicited.     

Early Life Stress and Post-Weaning High Fat Diet Alter Tyrosine Hydroxylase Regulation and AT1 Receptor Expression in the Adrenal Gland in a Sex Dependent Manner

Previous studies have shown that early life stress induced by maternal separation or non-handling can lead to behavioural deficits in rats and that these deficits can be alleviated by providing palatable cafeteria high-fat diet (HFD). In these studies we investigated the effects of maternal separation or non-handling and HFD on tyrosine hydroxylase (TH) protein and TH phosphorylation at Ser40 (pSer40TH) and the expression of angiotensin II receptor type 1 (AT1R) protein in the adrenal gland as markers of sympatho-adrenomedullary activation. After littering, Sprague–Dawley rats were assigned to short maternal separation, S15 (15 min), prolonged maternal separation, S180 (180 min) daily from postnatal days 2–14 or were non-handled (NH) until weaning. Siblings were exposed to HFD or chow from day 21 until 19 weeks when adrenals were harvested. Maternal separation and non-handling had no effects on adrenal TH protein in both sexes. We found an effect of HFD only in the females; HFD significantly increased TH levels in NH rats and pSer40TH in S180 rats (relative to corresponding chow-fed groups), but had no effect on AT1R expression in any group. In contrast, in male rats HFD had no effect on TH protein levels, but significantly increased pSer40TH across all treatment groups. There was no effect of HFD on AT1R expression in male rats; however, maternal separation (for 15 or 180 min) caused significant increases in AT1R expression (relative to NH group regardless of diet). This is the first study to report that early life stress and diet modulate TH protein, pSer40TH and AT1R protein levels in the adrenal gland in a sex dependent manner. These results are interpreted in respect to the potential adverse effects that these changes in the adrenal gland may have in males and females in adult life.     

NOD2 gene mutations associate weakly with ulcerative colitis but not with Crohn's disease in Indian patients with inflammatory bowel disease

Background

Three mutations (two missense and one frameshift) in the NOD2 gene are associated with Crohn's disease (CD) in a proportion of patients with Crohn's disease in North America, Europe and Australia. These three mutations are not found in Indian patients with CD. We undertook new studies to identify polymorphisms in the NOD2 gene in the Indian population and to detect whether any of these were associated with inflammatory bowel disease (IBD) in this population.

Methods

Individual exons of the NOD2 gene were amplified by PCR and subjected to denaturing high performance liquid chromatography (DHPLC) to detect heteroduplex formation. All 12 exons of the NOD2 gene were amplified and Sanger-sequenced to detect polymorphisms in the NOD2 gene. 310 patients with CD, 318 patients with ulcerative colitis (UC) and 442 healthy controls (HC) were recruited for association studies. DNA from these participants was evaluated for the identified eight polymorphisms by Sequenom analysis.

Results

Heteroduplex formation was noted by DHPLC in exons 2 and 4 of the NOD2 gene. Sequencing of the entire NOD2 gene data revealed eight polymorphisms – rs2067085, rs2066842, rs2066843, rs1861759, rs2111235, rs5743266, rs2076753, and rs5743291 – of which the latter four were described for the first time in Indians. None of these polymorphisms was associated with CD. The SNPs rs2066842 and rs2066843 were in significant linkage disequilibrium. Both SNPs showed a significant association with UC (P = 0.03 and 0.04 respectively; odds ratio 1.44 and 1.41 respectively).

Conclusion

Four NOD2 polymorphisms were identified for the first time in the Indian population. Of 8 NOD2 polymorphisms, none were associated with CD but two were weakly associated with UC. NOD2 polymorphisms do not play a major role in CD genesis in India.