Chelating ion-exchanger containing ben-zoylacetanilide moiety: Part II-Separation of beryllium(IT) and uranium(VI) from other metal ions

538-540The sorption patterns of Na(I), K(I), Be(II), Ca(II), Mg(II), Cu(II), Co(II), Ni(II), Al(m), Fe(ID), Ti(IY) and U(VI) on macroreticular polystyrene based chelating resin containing benzoylacetanilide functional group have been studied as a function of pH. The selective sorption of Be(II) and U(VI) at pH 4.0 and 3.2 respectively has been utilized for the separation prior to the determination of these metal ions

Repair of ultraviolet light-induced DNA damage in cholera bacteriophages

DNA repair-proficient and -deficient strains of Vibrio cholerae were used to examine host cell reactivation, Weigle reactivation and photoreactivation of u.v.-irradiated cholera bacteriophages. u.v. light-induced DNA damage in phages of different morphological and serological groups could be efficiently photoreactivated. Host cell reactivation of irradiated phages of different groups was different on the same indicator host. Phage Φ149 was the most sensitive, and Φ138 the most resistant to u.v. irradiation. While Φ138 showed appreciable host cell reactivation, this was minimal for Φ149. Attempts to demonstrate Weigle reactivation of u.v.-irradiated cholera phages were not successful, although u.v.-induced filamentation of host cells was observed

Spectrophotometric Determination of Ru(III) & Os(VIII) with Acetothioacetanilide

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Lysis of vibrio cholerae cells: direct isolation of the outer membrane from whole cells by treatment with urea

Cells of Vibrio cholerae underwent rapid autolysis when suspended in media of low osmolarity under non-growing conditions. Chaotropes like urea and guanidine. HCl which are potent protein denaturants caused complete and immediate lysis of whole cells. This unique sensitivity of V. cholerae to protein denaturants led to the development of a rapid method for the selective isolation of the outer membrane upon treatment of whole cells with urea. The composition of the outer membrane isolated from both whole cells and crude envelopes by treatment with urea was comparable with that of the outer membrane isolated by other conventional methods

Construction of shuttle vectors for cloning in Vibrio cholerae and Escherichia coli

Starting from a naturally occurring cryptic plasmid pVC540 of Vibrio cholerae non-OI. strain 1095, a number of plasmid vectors have been constructed for cloning genes inVibrio cholerae by introducing antibiotic resistance markers containing a set of unique cloning sites. The constructs pVC810 and pVE920 have the origins of both Vibrio cholerae and Escherichia coli replicons and are stable in both organisms in the absence of selective pressure. These plasmids can serve as shuttle vectors between Escherichia coli and Vibrio cholerae. The plasmid vectors reported here along with the demonstration of transformation in Vibrio cholerae by plasmid DNA will facilitate genetic analysis of this important human pathogen

Visual Documentation of the Project titled Health Communications Strategies and Best Practices in Covid-19 & Amphan Cyclone Affected Communities in South Bengal: A Study of Nadia & South 24 Parganas Districts

Visual Documentation of the Project titled "Health Communications Strategies and Best Practices in Covid-19 & Amphan Cyclone Affected Communities in South Bengal: A Study of Nadia & South 24 Parganas Districts". Project undertaken by MANAS, Nadia, West Bengal, India during 2021-22, and supported by NCSTC-DST, Government of India vide project no: CO/R/FP/G49/2020

Stress response in pathogenic bacteria

Bacterial pathogens survive under two entirely different conditions, namely, their natural environment and in their hosts. Response of these pathogens to stresses encountered during transition from the natural environment to human hosts has been described. The virulence determinants of pathogenic bacteria are under the control of transcriptional activators which respond to fluctuations in growth temperature, osmolarity, metal ion concentration and oxygen tension of the environment. The regulation of stress induced genes may occur at the level of transcription or translation or by post-translational modifications. Under certain stress conditions local changes in the superhelicity of DNA induce or repress genes. In addition to their role in survival of bacteria under stressful situations, the stress induced proteins are also implicated in the manifestation of pathogenicity of bacterial pathogensin vivo

Cloning and characterization of mutL and mutS genes of Vibrio cholerae: nucleotide sequence of the mutL gene

The mutL and mutS genes of Vibrio cholerae have been identified using interspecific complementation of Escherichia coli mutL and mutS mutants with plasmids containing the gene bank of V. cholerae. The recombinant plasmid pJT470, containing a 4.7 kb fragment of V. cholerae DNA codes for a protein of molecular weight 92,000. The product of this gene reduces the spontaneous mutation frequency of the E. coli mutS mutant. The plasmid, designated pJT250, containing a 2.5 kb DNA fragment of V. cholerae and coding for a protein of molecular weight 62,000, complements the mutL gene function of E. coli mutL mutants. These gene products are involved in the repair of mismatches in DNA. The complete nucleotide sequence of mutL gene of V. cholerae has been determined

Repression of the alkaline phosphatase of Vibrio cholerae

The synthesis of alkaline phosphatase by two strains of Vibrio cholerae belonging to the Inaba and Ogawa serotypes has been examined in relation to the phosphate concentration of the culture medium. The synthesis of the enzyme in both strains was repressed in cells grown in the presence of a high concentration of inorganic phosphate. Lowering the phosphate content of the growth medium led to a derepression of enzyme activity. The presence of glucose in low phosphate medium stimulated the degree of derepression. The synthesis of the enzyme by strain Inaba 569B was more sensitive to inorganic phosphate than that of strain Ogawa 154. The enzyme was presumably located in the periplasmic space since it was released when the organisms were converted to spheroplasts