Suruchi M. Khanna

Bordetella pertussis, the causative agent of whooping cough, is an opportunistic virulent bacterial pathogen that is resistant to a wide range of antibiotics due to a variety of resistance mechanisms. Looking at the increasing number of infections caused by B. pertussis and its resistance to diverse antibiotics, it is essential to develop alternative strategies to fight against B. pertussis. Diaminopimelate epimerase (DapF) is an important enzyme of the lysine biosynthesis pathway in B. pertussis that catalyzes the formation of meso-2, 6-diaminoheptanedioate (meso-DAP), which is an important step in lysine metabolism. Therefore, Bordetella pertussis diaminopimelate epimerase (DapF) becomes an ideal target for antimicrobial drug development. In the present study, computational modelling, functional characterization, binding studies, and docking studies of BpDapF with lead compounds were carried out using different in silico tools. In silico prediction results in the secondary structure, 3-D structure analysis, and protein-protein interaction analysis of BpDapF. Docking studies further showed the respective amino acid residues for ligands in the phosphate‑binding loop of BpDapF play a vital role in the formation of H‑bonds with these ligands. The site where the ligand was bound is a deep groove, which is regarded as the binding cavity of the protein. Biochemical studies indicated that Limonin (binding energy − 8.8 kcal/mol), Ajmalicine (binding energy − 8.7 kcal/mol), Clinafloxacin (binding energy − 8.3 kcal/mol), Dexamethasone (binding energy − 8.2 kcal/mol), and Tetracycline (binding energy − 8.1 kcal/mol) exhibited promising binding towards the drug target DapF of B. pertussis in comparison with the binding between other drugs and act as the potential inhibitors of BpDapF that eventually can reduce the catalytic activity of BpDapF.

Water deficit stress is one of the chief abiotic stresses adversely affecting plant endurance leading serious effects on plant metabolism. Depending upon strength and duration of water deficit conditions, plants adjust a series of physiological, cellular and molecular mechanisms aiming a correct stress response. Some of the responses of plants to water stress include decreased growth and development and hence decrease in fresh biomass, decreased content of chlorophyll and hence the decreased rate of photosynthesis, decrease in leaf relative water content (RWC) and increased accumulation of osmolytes like proline, sucrose, soluble carbohydrates, etc. Several enzymes involved in carbohydrate metabolism seem to play a role in the multi-layered response of plants to water deficiency. Glycolysis is a central metabolic pathway that provide elasticity when production of energy for existence is confronted and is modulated to establish a novel homeostasis under stress conditions in plants. Evidence for the participation of glycolytic genes, proteins and enzymes in response to stress is established by the fact that their expression is deeply affected by exposure of plant tissues to environmental stresses such as drought. Keeping in mind the importance of glycolytic pathway during stress conditions in plants, the impact of the drought stress on plant glycolysis is the subject of current review. In addition, plant physiology and carbohydrate metabolism under drought stress are also discussed.

The effect of dehydration on the specific activities and transcript levels of several glycolytic enzymes was determined in two chickpea (Cicer arietinum L.) cultivars- Pusa362 (drought tolerant) and SBD377 (drought sensitive). Dehydration treatment was imposed on 6 days old chickpea seedlings by removing them from pots and keeping them on table top on 3MM Whatman paper at room temperature for 5 h. The stress imposed was judged by determining relative water content (RWC) and proline content. RWC decreased and proline content accumulated after five hours of dehydration treatment. The decline in RWC was higher in SBD377 than in Pusa362, while varietal differences were absent in proline content. With the exception of NADP-glyceraldehyde-3-phospahte dehydrogense, whose activity as well as transcript level showed marginal decrease in both the varieties, dehydration had little effect on all glycolytic enzymes studied.

Genetic diversity and relationships within and among members of the primary gene pool of chickpea, including 38 accessions of Cicer arietinum, six of C. reticulatum,, and four of C. echinospermum, were investigated using 31 ISSR markers. The study revealed moderate diversity, detecting 141 fragments, of which 79 (56%) were polymorphic. Averages were 0.125 for polymorphic information content, 0.350 for marker index, and 0.715 for resolving power. The UPGMA dendrogram and the principal coordinate analysis revealed a clear differentiation between wild and cultivated accessions. The clustering pattern did not strictly follow the grouping of accessions by geographic origin but was in good agreement with the pedigree data and the seed type. The study demonstrates that ISSRs provide promising marker tools in revealing genetic diversity and relationships in chickpea and can contribute to efficient identification, conservation, and utilization of germplasm for plant improvement through conventional as well as molecular breeding approaches.