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J Oreglia

Publications and source records attributed to J Oreglia.

11 recordsLinked to original sources
PubMed1992

Structure of the gene complementing uvr-402 in Streptococcus pneumoniae: homology with Escherichia coli uvrB and the homologous gene in Micrococcus luteus.

The repair ability for UV-induced damage observed for Streptococcus pneumoniae proceeds through a system similar to the Uvr-dependent system in Escherichia coli. The DNA sequence of a gene complementing uvr-402, a mutation conferring UV sensitivity, was determined. Alignments of the deduced amino acid sequence revealed an extensive sequence homology of 55% with the UvrB protein of E. coli and 59% with the UvrB-homologous protein of Micrococcus luteus. Nucleotide-binding site consensus was observed. The high conservation of the uvrB-like gene among these three species suggests that the role of the UvrB protein and excision repair in general might be very important for cell survival.

Amino Acid Sequence↗
PubMed1990

Isolation and characterization of a restriction and modification deficient mutant of Brevibacterium lactofermentum.

In order to facilitate genetic engineering in amino-acid producing bacteria we have isolated two restriction-deficient Brevibacterium lactofermentum strains. They have been selected for their ability to obtain a high yield of plaques from CL31 phage which was grown on Corynebacterium lilium. These mutant strains do not restrict either phage DNA by transfection or DNA from the shuttle vector pBLA extracted from Escherichia coli by protoplast transformation. These mutants have also lost modification activity. We also report the presence of a restriction modification system in C. lilium ATCC 15990.

Bacteriophages↗
PubMed1990

Transfer of plasmid DNA to Brevibacterium lactofermentum by electrotransformation.

The Escherichia coli-Brevibacterium lactofermentum shuttle vector pBLA was introduced into intact cells of B. lactofermentum by electrotransformation. Several parameters of this procedure such as voltage and cell concentration were analysed. Optimal conditions gave an efficiency of 10(6) transformants per microgram of DNA. Two recalcitrant strains could be electrotransformed when an ampicillin pretreatment step was used. Electrotransformation experiments using DNAase or different structural forms of plasmid DNA showed that the electrotransformation process is quite different from natural transformation involving competence development. Restriction-modification-proficient B. lactofermentum could be efficiently electrotransformed with pBLA DNA isolated from E. coli. This restriction-modification system therefore seems to be overcome by electrotransformation. Thus electrotransformation may efficiently replace the protoplast bacterial transformation method.

Ampicillin↗
PubMed1986

A shuttle vector system for Brevibacterium lactofermentum.

We have constructed a shuttle vector that replicates in Escherichia coli, Corynebacterium glutamicum and Brevibacterium lactofermentum, by fusion of a 4.4-kb cryptic plasmid isolated from B. lactofermentum and a derivative of pBR322. Resistance to erythromycin which is expressed in all three bacteria has been a useful selective marker. The frequency of homospecific transformation was 1.5 X 10(5) transformants/micrograms of hybrid plasmid DNA.

Brevibacterium↗
PubMed1985

Transfection of Corynebacterium lilium protoplasts.

A protoplast transfection system has been developed for a lysine-producing bacterium, Corynebacterium lilium, using the DNA of phage CL31. Phage CL31 is lytic and specific to C. lilium and has a genome of approximately 48 kb. The transfection procedure involves a polyethylene-glycol-mediated introduction of the DNA into lysozyme-treated cells and has a maximum efficiency of 3 X 10(4) transfectants per microgram DNA.

Bacteriophages↗
PubMed1975

[Lethality of the dnaB thermosensitive mutation of E. coli : comparison with thymine-less death].

In a dnaB thermosensitive mutant of the bacterium E. coli, a shift to non-permissive conditions leads to the immediate cessation of DNA synthesis and results in a sizable loss of viability. Under conditions where protein synthesis is inhibited, either by addition of antibiotics (chloramphenicol, rifampicin) or by amino-acids starvation, there is a marked increase in viability. This is reminiscent of the behavior of thymine-deprived bacteria and suggests that both types of death, induced by a block in the displacement of the DNA-replicative fork, follow the same pattern.

Amino Acids↗