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C Koncz

Publications and source records attributed to C Koncz.

58 records · Page 4Linked to original sources

Megacinogenic plasmid from Bacillus megaterium 216.

Ability to produce megacin A, a bacteriocin of B. megaterium, was transferred from the strain B. megaterium 216 into auxotrophic derivatives of the strain B. megaterium KM via protoplast fusion and polyethylene-glycol-induced protoplast transformation by plasmid DNA, respectively. A 30.9 megadalton plasmid was detected in cells with MegA phenotype, and the loss of this phenotype was accompanied in each case with the elimination of that plasmid. The megacinogenic plasmid pBM309 has a single site for both BamHI and XhoI. It is cleaved by the endonucleases SalI, BglII, PstI, PvuII, and EcoRI into 3, 3, 4, 4, and 9 fragments, respectively. The physical map of this plasmid is presented.

Bacillus megaterium↗

Biochemical characterization of the restriction-modification system of Bacillus sphaericus.

A type II restriction endonuclease (endo R . Bsp) has been purified from Bacillus sphaericus to electrophoretic homogeneity. The enzyme appears to be a single polypeptide chain with a molecular weight of 35000. Its pH optimum is around 8.2, it requires 20 mM Mg2+ for optimal activity and it is inhibited by Zn2+. The yield of the enzyme is higher than that of any type II restriction endonuclease so far reported. The enzyme also cleaves single-stranded DNA, albeit at a slower rate. It seems likely that single-stranded DNA is cleaved at the same sequences as double-stranded DNA. Bacillus sphaericus also contains a modification methylase (meth M . Bsp) which completely protects the cell's own DNA against cleavage by its restriction endonuclease. The methylase activity has been partially purified, it copurifies with the nuclease until the next to the last step. The enzyme does not require ATP or Mg2+, it transfers the methyl group of S-adenosyl-methionine to cytosine residues of DNA. As the action of this methylase completely protects any DNA from endo R . Bsp cleavage, it seems likely that the methylase recognizes and methylates the same sequence (dG-dG-dC-dC) as the nuclease.

Bacillus↗

Novel monomeric luciferase enzymes as tools to study plant gene regulation in vivo.

Taking advantage of a specially constructed vector, luciferase LuxA and LuxB subunits were connected in frame to different amino acid linkers to reproduce a series of monomeric luciferase enzymes. A comparison of their activities in E. coli cells demonstrated that the length of the linkers positively affected activity. One luciferase fusion gene was expressed in plant cells, and we showed that this gene activity could be monitored directly without destructive sampling.

Amino Acid Sequence↗