Phytochemical, physicochemical, TLC, minerals analysis and in-vitro antioxidant activity of ethanolic extract of leaves of Heldigardia populifolia

The aim of present study was to investigate the preliminary phytochemical, physicochemical, TLC, minerals analysis and In-vitro antioxidant activity of leaves of ethanolic extract of Heldigardia populifolia. The preliminary phytochemical screening of ethanolic extract showed the presence of triterpenoids, flavonoids, glycosides, sterols, steroids, phenols, carbohydrates and saponins. The composition of minerals found in the leaf powder was within the permissible limits. TLC analysis of ethanol extract showed the five spots which indicate the presence of five phytoconstituents. The extractive value of ethanol was high than acetone. Ash values were within the limits. The in-vitro antioxidant activity of ethanolic extract increased with increasing the concentration. The ethanolic extract in all the concentration showed the significant antioxidant activity

Water Microbiology. Bacterial Pathogens and Water

Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters

Beckmann rearrangement of α-oximinoketones

963-965The Beckmann rearrangement of α-oximinoketones gives benzoic acids as chief isolable products. Both first order and second order Beckmann rearrangements have been observed. The occurrence of first order Beckmann rearrangement in these oximinocarbonyl compounds is confirmed through the identification of the products obtained

Sequence-induced trimerization of phospholipase A2: structure of a trimeric isoform of PLA2 from common krait (Bungarus caeruleus) at 2.5 Å resolution

The structure of a novel trimeric isoform of phospholipase A2 has been determined at 2.5 Å resolution. The trimer formation occurs in such a way that the active sites of all the three molecules are fully exposed to the solvent, making the trimer a highly potent enzymatic unit

Sequence-induced trimerization of phospholipase A<SUB>2</SUB>: structure of a trimeric isoform of PLA<SUB>2</SUB> from common krait (Bungarus caeruleus) at 2.5 &#197; resolution

The venom of the common Indian krait (Bungarus caeruleus) contains about a dozen isoforms of phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>), which exist in different oligomeric forms as well as in complexes with low-molecular-weight ligands. The basic objective of multimerization and complexation is either to inactivate PLA<SUB>2</SUB> in the venom for long-term storage, to generate a new PLA<SUB>2</SUB> function or to make a more lethal assembly. The current isoform was isolated from the venom of B. caeruleus. Dynamic light-scattering studies indicated the presence of a stable trimeric association of this PLA<SUB>2</SUB>. Its primary sequence was determined by cDNA cloning. The purified protein was crystallized with 2.8 M NaCl as a precipitating agent using the sitting-drop vapour-diffusion method. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 80.9, b = 80.5, c = 57.1 &#197;, &#946;= 90.3&#176;. The structure was refined to a final R factor of 0.198. This is a novel trimeric PLA<SUB>2</SUB> structure in which the central pore formed by the association of three molecules is filled with water molecules. The interactions across the pore take place via multiple water bridges primarily to the side chains of Arg, Lys and Thr residues. Approximately 12% of the total solvent-accessible surface area is buried in the core of the trimer. The active sites of all three molecules are located on the surface and are fully exposed to the solvent, resulting in a highly potent enzymatic unit

Crystal structure of a carbohydrate induced homodimer of phospholipase A<SUB>2</SUB> from Bungarus caeruleus at 2.1 Å resolution

This is the first crystal structure of a carbohydrate induced dimer of phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>). This is an endogenous complex formed between two PLA<SUB>2</SUB> molecules and two mannoses. It was isolated from Krait venom (Bungarus caeruleus) and crystallized as such. The complete amino acid sequence of PLA<SUB>2</SUB> was determined using cDNA method. Three-dimensional structure of the complex has been solved with molecular replacement method and refined to a final R-factor of 0.192 for all the data in the resolution range 20.0-2.1 &#197;. The presence of mannose molecules in the protein crystals was confirmed using dinitrosalicylic acid test and the molecular weight of the dimer was verified with MALDI-TOF. As indicated by dynamic light scattering and analytical ultracentrifugation the dimer was also stable in solution. The good quality non-protein electron density at the interface of two PLA<SUB>2</SUB> molecules enabled us to model two mannoses. The mannoses are involved extensively in interactions with protein atoms of both PLA<SUB>2</SUB> molecules. Some of the critical amino acid residues such as Asp 49 and Tyr 31, which are part of the substrate-binding site, are found facing the interface and interacting with mannoses. The structure of the complex clearly shows that the dimerization is caused by mannoses and it results in the loss of enzymatic activity