The Genomes of Desulfovibrio gigas and D. vulgaris

Abstract

Yee & Inouye (1982) described a new electrophoretic procedure for sizing the prokaryotic genome. In principle, a digest of genomic DNA with a six-base recognition restriction enzyme is resolved by electrophoresis in agarose. The DNA in a strip of the agar is re-digested with a second such restriction enzyme and resolved by electrophoresis at right angles to the original current. Appropriate molecular weight markers are included at the second stage. Fragments are then sized with reference to the markers and summed to give the genome size. This procedure is complementary to, and consistent with, DNA reassociation curves, analyses of minimum DNA contents or sizing of electron micrographs (see Yee & Inouye, 1982).We have applied this technique to single strains of Desulfovibriogigas and D . vulgaris, in which we have also observed plasmids by conventional electrophoresis; we have also examined 12 other strains of Desulfovibrio for plasmids and observed them in two. METHODSDesulfovibrio gigas (NCIMB 9332), kindly provided by Dr E. C. Hatchikian, (CNRS, Marseille, France), was grown in a simple wier-type chemostat ( V , 540 ml) at D = 0.025 or 0.03 h-under 0,-free N2 at 28 "C in lactatesulphate medium C (Postgate, 1984) modified so that the population was limited by the N supply by including only 0.03 g NH4Cl 1-I. Periodic cultural and visual checks were made for contamination (Postgate, 1984); none was present in any of the experiments reported here. Desulfovibrio vulgaris Hildenborough (NCIMB 8303) was grown in batch cultures (20 or 200 ml) to stationary phase under N, and was taken as N-limited. Desulfouibrio gigas and some other desulfovibrios (Table 2) were grown in normal medium C with extra NaCl as necessary. Escherichia coli

Insertional mutagenesis by random cloning of antibiotic resistance genes into the genome of the cyanobacterium Synechocystis strain PCC 6803

“…It has also been found in the unicellular cyanobacterium Synechococcus sp. (16,25), Azotobacter vinelandii (34), Desulfovibrio gigas (33), and the radioresistant bacterium Deinecoccocus radiatus (18). In E. coli growing at a doubling time of 40 min, there is an average of only two genomes per cell (28).…”

Genome Copy Numbers and Gene Conversion in Methanogenic Archaea

“…The beststudied Gram-positive bacterium, Bacillus subtilis, is also monoploid (47), as are several additional species. However, other bacterial species have been shown to be polyploid, e.g., Deinococcus radiodurans, Desulfovibrio gigas, and Borrelia hermsii (15,19,30). Since the number of "exceptions" has become greater than the number of species that adhere to the rule, it might be questioned whether monoploidy is really "typical" for bacteria.…”

Identification of a large family of genes for putative chemoreceptor proteins in an ordered library of the Desulfovibrio vulgaris Hildenborough genome

“…By accepting a genome size of 1,720 kb (22), a conservative estimate of 16 dcr genes per genome and 2.2 kb per gene (as for dcrA), it appears that 2% of the genome is allocated to accommodate the dcr gene family. The tRNA gene family is the only one in prokaryotes that accommodates a larger number of genes.…”

“…Generation of a physical map considerably facilitates further gene cloning and sequencing work. The generation of an ordered library for the genome of the D. vulgaris Hildenborough, an anaerobically living sulfate-reducing bacterium with a reported genome size of 1,720 kb (22), is described here. The ordered library proved to be indispensable for the rapid characterization of the dcr gene family.…”