Response of chickpea genotypes to Agrobacterium-mediated delivery of Chickpea chlorotic dwarf virus (CpCDV) genome and identification of resistance source

Chickpea stunt disease caused by Chickpea chlorotic dwarf virus (CpCDV) (genus Mastrevirus, family Geminiviridae) is the most important biotic stress affecting chickpea crops worldwide. A survey conducted on the incidence of stunt disease clearly revealed high incidence of the disease with severe symptom expression in both indigenous and imported genotypes. To manage the disease in a sustainable way, resistant genotypes need to be bred by adopting objective and precise assessment of the disease response of chickpea genotypes. At present, evaluation of CpCDV resistance is conducted on the basis of natural infection in the field, which is bound to be erroneous due to vagaries in vector population. To circumvent the above problems, we devised an agroinoculation technique that involves the delivery of viral genomic DNA through Agrobacterium tumefaciens. An objective scoring system assigning quantitative value to different symptoms has been evolved to assess the response of chickpea genotypes to CpCDV inoculation. Using the inoculation and scoring techniques, we screened 70 genotypes, which helped in differentiating field resistance that is more due to resistance to vector feeding than resistance to the virus.     

Safety evaluation of BacoMind in healthy volunteers: a phase I study.

BacoMind is an enriched phytochemical composition of Bacopa monniera (B. monniera), a common medicinal plant used in the traditional systems of medicine as a memory-enhancing agent. BacoMind was standardized with reference to bioactive compounds and was evaluated for short-term safety and tolerability in healthy adult volunteers. The study plan employed randomized, open label, dose escalation design. Each of 23 participants were orally given one single capsule of BacoMind daily for 30 days, i.e., 300 mg for first 15 days and 450 mg for next 15 days. Detailed examination of clinical, hematological, biochemical and electrocardiographic parameters done in pre and post-treatment periods did not indicate any untoward effects in any of the treated volunteers. Mild adverse events related to gastrointestinal system were observed in the trial, which subsided spontaneously. BacoMind was found to meet the safety criteria at the dose administered for the given duration of trial period in healthy adult volunteers.     

Zoological evidence to the origin of flood-waters and their role in vector distribution

The study of the flood-waters revealed that the breach of irrigation channels due to heavy downpour, triggered the floods, as the first flood-waters largely contained characteristic riverine fauna. Later on, the riverine fauna was outnumbered by pond fauna indicating the overflow from ponds, adding to the amount of flood-waters. The flood-waters play a significant role in the distribution of animals in general and vectors in particular. The chief vectors included Cyclops, Lymnaea, Planorbis and five genera of fishes. Pockets of stagnant flood-water provide a breeding ground for mosquitoes to create a future nuisance. The faunal study of flood-waters offers a proof to their origin, which otherwise requires a manual survey.     

Rab27a regulates epithelial sodium channel (ENaC) activity through synaptotagmin-like protein (SLP-5) and Munc13-4 effector mechanism

Liddle's syndrome (excessive absorption of sodium ions) and PHA-1 (pseudohypoaldosteronism type 1) with decreased sodium absorption are caused by the mutations in the amiloride-sensitive epithelial sodium channel ENaC. Rab proteins are small GTPases involved in vesicle transport, docking, and fusion. Earlier, we reported that Rab27a inhibits ENaC-mediated currents through protein-protein interaction in HT-29 cells. We hereby report that Rab27a-dependent inhibition is associated with the GTP/GDP status as constitutively active or GTPase-deficient mutant Q78L inhibits amiloride-sensitive currents whereas GDP-locked inactive mutant T23N showed no effect. In order to further explore the molecular mechanism of this regulation, we performed competitive assays with two Rab27a-binding proteins: synaptotagmin-like protein (SLP-5) and Munc13-4 (a putative priming factor for exocytosis). Both proteins eliminate negative modulation of Rab27a on ENaC function. The SLP-5 reversal of Rab27a effect was restricted to C-terminal C2A/C2B domains assigned for putative phospholipids-binding function while the Rab27a-binding SHD motif imparted higher inhibition. The ENaC-mediated currents remain unaffected by Rab27a though SLP-5 appears to strongly bind it. The immunoprecipitation experiments suggest that in the presence of excessive Munc13-4 and SLP-5 proteins, Rab27a interaction with ENaC is diminished. Munc13-4 and SLP-5 limit the Rab27a availability to ENaC, thus minimizing its effect on channel function. These observations decisively prove that Rab27a inhibits ENaC function through a complex mechanism that involves GTP/GDP status, and protein-protein interactions involving Munc13-4 and SLP-5 effector proteins.     

Synthesis of some substituted pyrazinopyridoindoles and 3D QSAR studies along with related compounds: piperazines, piperidines, pyrazinoisoquinolines, and diphenhydramine, and its semi-rigid analogs as antihistamines (H1)

3D QSAR studies on the title compounds led to the development of a model with three biophoric sites and six secondary sites viz. H-acceptor (ACC), H-donor (DON), heteroatom (presence), hydrophobic (hydrophobicity), steric (refractivity), and a ring (presence) along with total hydrophobicity and total refractivity as global properties. The model predicted the test set of compounds reasonably well. Three of the five newly synthesized 2-substituted octahydropyrazinopyridoindoles have shown potent antihistaminic H₁ activity with less toxicity and sedation potential.     

Cellulose synthases and related enzymes

The discovery of a large number of genes encoding cellulose synthases and related glycosyltransferases in plants has led to a renewed interest in the biosynthesis of cell-wall polysaccharides. A number of approaches, including virus-induced gene silencing have proven useful in the functional analysis of these genes. X-ray analysis of the structures of a few glycosyltransferases has led to the identification and confirmation of the role of conserved residues within this group of enzymes. Analysis of related enzymes has provided useful information on the possible domain organization of cellulose synthases and the requirement for at least two separate glycosyltransferase activities in the processive synthesis of sugar chains.     

Fermentation behavior of osmophilic yeast Candida tropicalis isolated from the nectar of Hibiscus rosa sinensis flowers for xylitol production

Eighteen yeast species belonging to seven genera were isolated from ten samples of nectar from Hibiscus rosa sinensis and investigated for xylitol production using d-xylose as sole carbon source. Amongst these isolates, no. 10 was selected as the best xylitol producer and identified as Candida tropicalis on the basis of morphological, biochemical and 26S rDNA sequencing. C. tropicalis produced 12.11 gl⁻¹ of xylitol in presence of 50 gl⁻¹ of xylose in 72 h at pH 5, 30°C and 200 rpm. The strain of C. tropicalis obtained through xylose enrichment technique has resulted in a yield of 0.5 gg⁻¹ with a xylitol volumetric productivity of 1.07 gl⁻¹h⁻¹ in the presence of 300 gl⁻¹ of xylose through batch fermentation. This organism has been reported for the first time from Hibiscus rosa sinensis flowers. Realizing, the importance of this high valued compound, as a sugar substitute, xylose enrichment technique was developed in order to utilize even higher concentrations of xylose as substrate for maximum xylitol production.     

High-Resolution Structure of a Protein Spin-Label in a Solvent-Exposed β-Sheet and Comparison with DEER Spectroscopy

X-ray crystallography has been a useful tool in the development of site-directed spin labeling by resolving rotamers of the nitroxide spin-label side chain in a variety of α-helical environments. In this work, the crystal structure of a doubly spin-labeled N8C/K28C mutant of the B1 immunoglobulin-binding domain of protein G (GB1) was solved. The double mutant formed a domain-swapped dimer under crystallization conditions. Two rotameric states of the spin-label were resolved at the solvent-exposed α-helical site, at residue 28; these are in good agreement with rotamers previously reported for helical structures. The second site, at residue 8 on an interior β-strand, shows the presence of three distinct solvent-exposed side-chain rotamers. One of these rotamers is rarely observed within crystal structures of R1 sites and suggests that the H(α) and S(δ) hydrogen bond that is common to α-helical sites is absent at this interior β-strand residue. Variable temperature continuous wave (CW) experiments of the β-strand site showed two distinct components that were correlated to the rotameric states observed in crystallography. Interestingly, the CW data at room temperature could be fit without the use of an order parameter, which is consistent with the lack of the H(α) and S(δ) interaction. Additionally, double electron electron resonance (DEER) spectroscopy was performed on the GB1 double mutant in its monomeric form and yielded a most probable interspin distance of 25 ± 1 ?. In order to evaluate the accuracy of the measured DEER distance, the rotamers observed in the crystal structure of the domain-swapped GB1 dimer were modeled into a high-resolution structure of the wild type monomeric GB1. The distances generated in the resulting GB1 structural models match the most probable DEER distance within ～2 ?. The results are interesting as they indicate by direct experimental measurement that the rotameric states of R1 found in this crystal provide a very close match to the most probable distance measured by DEER.