Effects of Brain Ischemic Preconditioning on Cognitive Decline and Motor Incoordination in 3-Nitropropionic Acid-Intoxicated Rats: Probable Mechanisms of Action

Neurophysiology - The paradigm of brain ischemic preconditioning (BIP) rendering protection from succeeding chemical insults has not been established in vivo. Systemic administration of...     

In silico structural characterization and molecular docking studies of first glucuronoxylan-xylanohydrolase (Xyn30A) from family 30 glycosyl hydrolase (GH30) from Clostridium thermocellum

CtXynGH30 is a carbohydrate active modular enzyme and component of cellulosome of Clostridium thermocellum. The full length CtXynGH30 contains an N-terminal catalytic module named as Xyn30A and a family 6 carbohydrate binding module (CBM6) at C-terminus. Xyn30A was modeled by computer program Modeller9v8 taking crystal structure of XynC from B. subtilis as a template to generate the molecular model. Model refinement was done using energy minimization by implementing steepest descent algorithm with GROMOS96 43a1 force field. Quality assessment by Ramachandran plot showed that 91% amino acids lie in most favourable region and 9% in additional allowed region. Structural analysis depicted that Xyn30A has a (β/α)₈ barrel fold. Additionally, it had a β-strand rich structure called ‘side β-structure’ attached with main catalytic core. Structural superimposition reflected that Glu136 act as a catalytic acid/base while Glu225 act as a catalytic nucleophile. Multiple sequence alignment showed that these catalytic residues are conserved within the family. The docking results showed that these residues display polar interaction with linear and substituted xylo-oligosaccharides. The binding interaction of ligands depicted that aromatic amino acids Trp81, Tyr139, Trp143, Phe172, His198, Tyr200, Tyr227, Trp264 and Tyr265 create binding site pocket around the active site. We report overall structural feature, conserved active site residues and enzyme-ligand docking of first glucuronoxylan-xylanohydrolase (Xyn30A) of family 30 glycosyl hydrolase (GH30) from Clostridium thermocellum.     

Water stress alters characteristics of alkaline phosphatase inRhizobium andAzotobacter species

Rhizobium trifolii T19C andAzotobacter chroococcum B13 ware grown under polyethylene glycol (6000) induced water streas in the liquid media. Water stress at -200 and -300 kPa resulted in a several-fold increase in the activity of alkaline phosphatase in both bacteria. Optimum pH and temperature and thermostability of the enzyme were also affected by the water stress.     

Effect ofcis andtrans unsaturated fatty acids on the transport properties ofSalmonella typhimurium

The transport of α-methyl-D-glucoside and two aminoacids, L-phenylalanine and L-leucine by a temperature sensitive fatty acid requiring mutant ofSalmonella typhimurium was studied under conditions of supplementation withcis or trans-unsaturated fatty acids. The results of such experiments definitely establish a relationship between the fatty acids composition of the membrane and the transport property of the cells. Cells grown in the presence of trans-unsaturated fatty acids cannot transport so efficiently as compared to the cis-unsaturated fatty acid-grown cells except linolelaidic acid, atrans-trans-unsaturated fatty acid. Protein: phospholipid ratio of the membrane also varies significantly under such conditions. The affinity of L-phenylalanine transport carrier for the substrate changes remarkably in cells grown in the presence of differentcis or trans-unsaturated fatty acids and indicate the possible role of membrane lipids in membrane assembly as well as regulation of the activity of L-phenylalanine transport system.     

Antibacterial activity of colloidal copper nanoparticles against Gram-negative (Escherichia coli and Proteus vulgaris) bacteria

Antibacterial activities of as-synthesized nanoparticles have gained attention in past few years due to rapid phylogenesis of pathogens developing multi-drug resistance (MDR). Antibacterial activity of copper nanoparticles (CuNPs) on surrogate pathogenic Gram-negative bacteria Escherichia coli (MTCC no. 739) and Proteus vulgaris (MTCC no. 426) was evaluated under culture conditions. Three sets of colloidal CuNPs were synthesized by chemical reduction method with per batch yield of 0·2, 0·3 and 0·4 g. As-synthesized CuNPs possess identical plasmonic properties and have similar hydrodynamic particle sizes (11–14 nm). Antibacterial activities of CuNPs were evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests, cytoplasmic leakage and reactive oxygen species (ROS) assays. MIC and MBC tests revealed dose dependence bactericidal action. Growth curves of E. coli show faster growth inhibition along with higher cytoplasmic leakage than that of P. vulgaris. This might be because of increased membrane permeability of E. coli. CuNP–microorganism interaction induces oxidative stress generated by ROS. Leakage of cytoplasmic components, loss of membrane permeability and ROS generation are the primary causes of CuNP-induced bacterial cell death. As-synthesized CuNPs exhibiting promising antibacterial activities and could be a promising candidate for novel antibacterial agents.     

Comparative adsorption of human enteroviruses, simian rotavirus, and selected bacteriophages to soils.

Virus adsorption to soils is considered to be the most important factor in removing viruses after land treatment of wastewater. Most of the studies on virus adsorption to soils have utilized poliovirus as the model system. In the present study, comparative adsorption of a number of different types and strains of human enteroviruses and bacteriophages to nine different soil types was studied. Under the experimental conditions of this study, greater than 90% of all viruses adsorbed to a sandy loam soil except echovirus types 1, 12, and 29 and a simian rotavirus (SA-11), which adsorbed to a considerably lower degree. A great deal of variability was observed between adsorption of different strains of echovirus type 1, indicating that viral adsorption to soils is highly strain dependent. Of the five phages studied, f2 and phi X174 adsorbed the least. In addition to being dependent on type and strain of virus, adsorption was found to be influenced also by type of soil. Thus, soils having a saturated pH of less than 5 were generally good adsorbers. From these results, it appears that no one enterovirus or coliphage can be used as the sole model for determining the adsorptive behavior of viruses to soils and that no single soil can be used as the model for determining viral adsorptive capacity of all soil types.     

Distribution of Plasmids in Heterocystous Cyanobacteria

The distribution of plasmids was studied in 15 different heterocystous cyanobacteria using agarose gel electrophoresis. Out of these, six were found to possess only one plasmid DNA of size ranging from 30–33 mD. A simplified and less time consuming protocol for studying the plasmids has been suggested.     

Carbon Concentration Mechanism(s) in Unicellular Green Algae and Cyanobacteria

Unicellular green algae and cyanobacteria have mechanism(s) to actively concentrate dissolved inorganic carbon (DIC) into the cells, only if they are grown with air levels of CO₂. The DIC concentration mechanisms are environmental adaptations to actively transport and accumulate inorganic carbon into the chloroplasts of green algae or into the carboxysomes of cyanobacteria. The current working model of cyanobacterial carbon concentration mechanism consists of at least two basic components: an active C_i transport system and a Rubisco-rich polyhedral carboxysome. In case of unicellular green algae, the working model for DIC concentration mechanism includes several isoforms of carbonic anhydrase (CA), and ATPase driven active bicarbonate transporters at the plasmalemma and at the inner chloroplast envelopes. In the past twenty years, significant progress has been made in isolating and characterizing the isoforms of carbonic anhydrase. However, active transporters are yet to be characterized. This mini-review summarizes the current status of research on DIC-pumps including its significance and possible application to increase the productivity of plants of economic importance.