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Sung Kyun Chung

Publications and source records attributed to Sung Kyun Chung.

3 recordsLinked to original sources
PubMed2004

Construction of a pTOC-T vector using GST-ParE toxin for direct cloning and selection of PCR products.

Using linker insertion mutations, we determined the most stable region of the parE gene which encodes a toxic protein (ParE) that inhibits growth of Escherichia coli. The toxicity of ParE was sustained until a 144 bp linker was inserted into this region. We have developed a 3' T-overhang vector based on these characteristics of the GST-ParE toxin, and named pTOC-T. Because pTOC-T uses a post-segregational killing system, all transformants grown up on the plates can be considered as recombinants containing foreign DNA. pTOC-T not require X-Gal, IPTG or other substrates for selection. This T-vector using a positive selection system can be applied to various E. coli strains such as XL1-Blue, BL21, DH5alpha, JM109, and JM110.

Bacterial Toxins↗
PubMed2003

New integration vector using a cellulase gene as a screening marker for Lactobacillus.

The new integration vector for Lactobacillus, pJC4, was developed using the extracellular endoglucanase A gene (celA) of Clostridium thermocellum as a screening marker. pJC4 was transformed into four Lactobacillus species, Lb. johnsonii, Lb. gasseri, Lb. bulgaricus, and Lb. plantarum. In each species, the pJC4 integrants were easily and accurately detected by the appearance of a clear halo on a cellulase screening plate without any false transformants. Polymerase chain reaction and Southern hybridization indicated that all transformants with clear halos contained pJC4 in their chromosomal DNAs. The celA gene could be a useful screening marker for other lactic acid bacteria.

Cellulase↗