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J I Flock

Publications and source records attributed to J I Flock.

60 records · Page 4Linked to original sources
PubMed1984

Expression in Bacillus subtilis of the gene for human urogastrone using synthetic ribosome binding sites.

A chemically synthesised gene coding for human urogastrone which was earlier cloned in E. coli (Smith et al. 1982) has now been cloned into expression vectors for Bacillus subtilis. Two types of constructs have been made, one giving production of methionyl-urogastrone and the other giving rise to a methionyl-urogastrone-beta galactosidase fusion polypeptide facilitating quantification of expression levels. The ribosome binding sites used in the expression plasmids are synthetically made oligonucleotides residing on short restriction fragments to allow easy replacement by other ribosome binding sites. Using "shuttle" vectors and constitutive promoters from Bacillus phages phi 105 and SPP1, we were able to detect levels of expression amounting to a few thousand molecules per cell during logarithmic growth in both E. coli and B. subtilis.

Amino Acid Sequence↗
PubMed1981

Cloning and expression of bacteriophage SP02 DNAZ polymerase gene L in Bacillus subtilis, using the Staphylococcus aureus plasmid pC194.

HindIII restriction endonuclease fragments of DNA from temperate Bacillus subtilis bacteriophage SP02 were cloned in B. subtilis by using the plasmid pC194. Three hybrid plasmids which permit growth of the mutant SP02 susL244 in suppressor-negative bacteria were isolated. SP02 gene L is thought to code for a DNA polymerase essential for autonomous replication of SP02 DNA. Extracts of bacteria carrying one of these hybrid plasmids, pC194-96, had 10- to 30-fold increased DNA polymerase activity. The plasmid-induced DNA polymerase activity differed from that of the known B. subtilis DNA polymerases in several respects. The results of the experiments support the idea that phage SP02 codes for a new DNA polymerase.

Bacillus subtilis↗
PubMed1978

Transfection with replicating DNA from the temperate Bacillus bacteriophage phi 105 and with T4-ligase treated phi105 DNA: the importance in transfection of being longer than genome-length.

Replicating phage DNA extracted from Bacillus subtilis infected with phage phi 105 has a higher activity in transfection than mature DNA. By heteroduplex analysis it was shown that this DNA contains concatemeric molecules. Concatemers, constructed in vitro by treatment of mature DNA with T4-ligase also have an increased activity in transfection. DNA showing an increased activity in transfection does not have a requirement for more than one molecule per transfection event as is typically found for transfection with mature phi 105 DNA. An explanation is given for this difference suggesting that the structure of the ends of the transfecting molecules play an important role intransfection.

Bacillus subtilis↗
PubMed1977

Deletion mutants of temperate Bacillus subtilis bacteriophage phi105.

Six deletion mutants of temperate Bacillus subtilis phage phi105 have been isolated on the basis of their increased resistance to chelating agents. The size and position of the deletions was determined by electronmicroscopy of DNA heteroduplexes. All deletions are located in a region about 55-70% from one end of the DNA molecule, in the right half of the known genetic map of the phage. The segment 55-65% does not contain any genes essential for lytic growth or lysogenization. A gene(s) for immunity is located in a segment 65-70% from the left end. By electronmicroscopy by partially denatured phi105 DNA two A-T rich regions have been localized in the right half of the molecule. One of these regions falls within the non-essential 55-65% DNA segment.

Bacillus subtilis↗