Debarpita Ghosal

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Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma radiation [50 grays (Gy) per hour] or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared with radiation-sensitive bacteria and that(More)
Immense volumes of radioactive wastes, which were generated during nuclear weapons production, were disposed of directly in the ground during the Cold War, a period when national security priorities often surmounted concerns over the environment. The bacterium Deinococcus radiodurans is the most radiation-resistant organism known and is currently being(More)
The enzyme catechol 2,3-dioxygenase (C23O) encoded by the nahH gene of plasmid NAH7 converts catechol to alpha-hydroxymuconic epsilon-semialdehyde in Pseudomonas putida. We have cloned this structural gene into vectors pUC18 and pKT240, determined the nucleotide sequence and deduced the amino acid sequence. In comparison to the gene xylE of the TOL plasmid(More)
In Alcaligenes eutrophus JMP134, pJP4 carries the genes coding for 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3-Cba) degradation plus mercury resistance. The plasmid genes specifying 2,4-D and 3-Cba catabolism are organized in three operons: tfdA, tfdB, and tfdCDEF. Regulation of these operons by two unlinked genes, tfdR and tfdS, has been(More)
Gene nahG of naphthalene/salicylate catabolic plasmid NAH7 encodes a protein of molecular weight 45,000, salicylate hydroxylase. This enzyme catalyzes the formation of catechol from salicylate, a key intermediate in naphthalene catabolism. DNA sequence analysis of the 3.1-kilobase HindIII fragment containing the nahG locus reveals an open reading frame(More)
All of the structural genes for 3-chlorobenzoate degradation are clustered in a 4.2-kilobase (kb) region of plasmid pAC25 (or pAC27) in Pseudomonas putida. An approximate 10-kb DNA segment containing three structural genes for chlorocatechol metabolism present on plasmid pJP4 in Alcaligenes eutrophus shows homology with the above 4.2-kb region of pAC27. In(More)
The nah and sal operons of the 80-kilobase-pair (kb) NAH7 plasmid specify catabolism of naphthalene and salicylate under positive regulation by gene nahR. A 1.75-kb fragment (PstI-HindIII) cloned into the pCP13 derivative of vector RK2 complemented in trans five nahR mutations. The fragment sequence contained a 1,122-base-pair open reading frame with a(More)
The mode of degradation of various halogenated compounds in isolated pure cultures and the disposition of the degradative genes have been studied. In many cases the degradative genes are found to be clustered on plasmids and appear to be under positive control. Genetic selection in vivo and genetic manipulations in vitro have allowed construction of strains(More)
Alcaligenes eutrophus harboring plasmid pJP4 (strain JMP134) is capable of growing on both 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3-Cba), while Pseudomonas putida carrying plasmid pAC27 (strain AC867) can utilize only 3-Cba as the sole carbon source. The tfdCDEF operon of the pJP4 plasmid and the clcABD operon of plasmid pAC27 each encode(More)