Purified C-phycocyanin from <Emphasis Type="Italic">Spirulina platensis</Emphasis> (Nordstedt) Geitler: a novel and potent agent against drug resistant bacteria

The experimental data on the study of the antibacterial activity of purified phycocyanin, a protein-bound pigment isolated from blue-green alga, Spirulina platensis (Nordstedt) Geitler, Oscillatoriaceae are generalized and it was shown that phycocyanin was able to markedly inhibit the growth of drug resistant bacteria Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus while, no activity was recorded in Acinetobacter baumanii and Enterococcus durans, this is the first report of the activity of purified C-phycocyanin against drug resistant bacteria. The possible use of phycocyanin as a drug with associated antibacterial activity is discussed.     

MU2 and HP1a regulate the recognition of double strand breaks in Drosophila melanogaster

Chromatin structure regulates the dynamics of the recognition and repair of DNA double strand breaks; open chromatin enhances the recruitment of DNA damage response factors, while compact chromatin is refractory to the assembly of radiation-induced repair foci. MU2, an orthologue of human MDC1, a scaffold for ionizing radiation-induced repair foci, is a widely distributed chromosomal protein in Drosophila melanogaster that moves to DNA repair foci after irradiation. Here we show using yeast 2 hybrid screens and co-immunoprecipitation that MU2 binds the chromoshadow domain of the heterochromatin protein HP1 in untreated cells. We asked what role HP1 plays in the formation of repair foci and cell cycle control in response to DNA damage. After irradiation repair foci form in heterochromatin but are shunted to the edge of heterochromatic regions an HP1-dependent manner, suggesting compartmentalized repair. Hydroxyurea-induced repair foci that form at collapsed replication forks, however, remain in the heterochromatic compartment. HP1a depletion in irradiated imaginal disc cells increases apoptosis and disrupts G2/M arrest. Further, cells irradiated in mitosis produced more and brighter repair foci than to cells irradiated during interphase. Thus, the interplay between MU2 and HP1a is dynamic and may be different in euchromatin and heterochromatin during DNA break recognition and repair.     

Antibacterial activity of three South Indian seagrasses, <Emphasis Type="Italic">Cymodocea serrulata</Emphasis>, <Emphasis Type="Italic">Halophila ovalis</Emphasis> and <Emphasis Type="Italic">Zostera capensis</Emphasis>

The antibacterial properties of the three seagrasses namely Cymodocea serrulata, Halophila ovalis and Zostera capensis were tested against the human pathogens Staphylococcus aureus, Bacillus cereus, B. subtilis, Escherichia coli, Salmonella paratyphi, Salmonella typhimurium and Micrococcus luteus, using six different solvents namely, petroleum ether, chloroform, ethyl acetate, acetone, methanol and water. Ethyl acetate and methanol extracts showed maximum activity against most of the pathogens when compared to other solvents. Experiments are underway to isolate active compound(s) implicated in controlling the growth of the pathogens in vitro.     

Enantioselective reduction of aryl and hetero aryl methyl ketones using plant cell suspension cultures of Vigna radiata

Vigna radiata was investigated as whole cell catalyst for the bioreduction of aryl and heteroaryl prochiral ketones into optically active alcohols. The study indicates selective bioreduction of different substituted aryl and heteroaryl ketones (1a–12a) to their respective (S) – chiral alcohols (1b–12b) in good to high enantioselectivity (77.7–97.5%) with very good yields (73–82%). The results obtained confirm that the keto reductase has broad substrate specificity and selectivity in catalyzing both six and five-membered heteroaryl methyl ketones. The current methodology substantiates a promising and alternative green approach for the synthesis of secondary chiral alcohols of biological importance in a mild, cheap and environmentally benign process.