Expression of virulence genes by Listeria monocytogenes J0161 in natural environment

Majority of studies concerning the gene expression of Listeria monocytogenes have been done on pure culture states. Our objective was to study L.monocytogenes in a co-cultured state and to understand if microbes in their natural state of existence are different in their expression than that of the purely cultured lab grown forms. For a long period discussions have been on the expression of prfA, (which is a virulence gene regulator) in a mammalian host and its role in causing the switch from a saprophytic to pathogenic form of L.monocytogenes. We, in this paper for the first time report the expression of prfA and other virulence genes by L.monocytogenes under different extracellular conditions, and also as a pure culture biofilms, that is different from the previous reports. We also report that the expression of prfA seems to vary considerably when co-cultured with Bacillus subtilis.

Laboratory efficacy of metabolites of Lagenidium giganteum (Couch) on Anopheles stephensi (Liston) after filterations by Column Chromatography.

This study was conducted in laboratory to evaluate the efficacy of filtered extracellular metabolites of Lagenidium giganteum against all the four instars of An. stephensi larvae. Fungal colonies have been cultured in PYG broth and after 15 days of culturing the fungus, metabolites have been filtered twice by whatman filter paper. These metabolites were again filtered by column chromatography and by rang syringe filters. Filtered metabolites were then used against all instars of An. stephensi larvae. The bioassays were conducted at five significantly different concentrations (1.68, 1.99, 2.17, 2.30, 2.40 ppm). The results suggest significant mortality on first three instar larvae and very low on fourth instar larvae.