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Objectives: A chaperonin, PsyGroELS, from the Antarctic psychrophilic bacterium Psychrobacter sp. PAMC21119, was examined for its role in cold adaptation when expressed in a mesophilic Escherichia coli strain., Results: Growth of E. coli harboring PsyGroELS at 10 °C was increased compared to the control strain. A co-expression system using PsyGroELS was developed to increase productivity of the psychrophilic enzyme PsyEst9. PsyEst9 was cloned and expressed using three E. coli variants that co-expressed GroELS from PAMC21119, E. coli, or Oleispira antarctica RB8(T). Co-expression with PsyGroELS was more effective for the production of PsyEst9 compared tothe other chaperonins., Conclusion: PsyGroELS confers cold tolerance to E. coli, and shows potential as an effective co-expression system for the stable production of psychrophilic proteins.

Escherichia coli strains were isolated from the feces of 130 diarrheic calves at different farms locations in Korea. The presence of the virulence genes, such as fanC, f41, f17a, eaeA, clpG, afa-8D, sta, stx1 and stx2, in each E. coli isolate was examined. Among the 314 isolates, 157 carried one or more of the virulence genes tested in this study. The most prevalent virulence gene was clpG (45.9%), although f17A (36.9%) and afa-8D (21.7%) were also frequently observed. The sta, stx1 and eaeA genes were detected in between approximately 13 and 17% of the isolates, and the fanC and fim41a genes were detected to a lesser extent. Collectively, our data indicated that diarrhea in calves in these locations can be ascribed to various virulence factors, and the pathogenesis may be more related to virulence genes such as, clpG, f17A, and afa-8D.

Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome worldwide. E. coli O26 and O111 are the serotypes most frequently isolated from human EHEC infections in Korea. Cattle are considered to be the major sources of E. coli O26 and O111. This study investigated the prevalence of E. coli O26 and O111 in fecal samples from cattle in Korea from April 2002 to March 2004. Out of 809 samples, 54 (6.67%), 37 (4.57%), and 16 (1.98%) tested positive for O26, O111, and both O26 and O111, respectively. Most of the E. coli O26 and O111 strains were isolated from May to October of each year. PCR analysis of the EHEC virulence markers revealed that most of the E. coli O26 and O111 isolates were positive for ehxA, eaeA and stx1 and/or stx2. These results suggest that the majority of Korean E. coli O26 and O111 isolates from cattle can cause serious diseases in humans.