Temperature shift-up leads to simultaneous and continuous plasmid DNA relaxation and induction of DnaK and GroEL proteins in anaerobically growing Escherichia coli cells

Abstract We previously reported that plasmid DNA in Escherichia coli cells growing under aerobic conditions relaxed immediately and transiently after heat shock (Mizushima, T., Natori, S. and Sekimizu, K., Mol. Gen. Genet. (1993) 238, 1–5). We next examined DNA relaxation and induction of heat shock proteins after heat shock in cells growing under anaerobic conditions. DNA in these cells relaxed rapidly (2 min) after heat shock (42°C), as was the case with aerobically growing cells, but full superhelicity was not recovered. The relaxed state of DNA topology was maintained for 60 min after heat shock. Induction of DnaK and GroEL proteins, which was transient in aerobically growing cells, was continuous in anaerobically growing cells. Therefore, induction of heat shock proteins correlated with DNA relaxation in both aerobic and anaerobic conditions.     

Titer and specificity of autoantibody to beta 2-microglobulin in sera from patients with rheumatic disease.

Sera from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) possessed higher titer of antibody to human β₂-microglobulin (β₂m) than those from healthy controls and patients with Behçet's disease in the enzyme-linked immunosorbent assay. It was also confirmed by the immunoprecipitation method. Anti-β₂m antibody in sera from those patients immunoprecipitated free β₂m but not β₂m in association with major histocompatibility complex class I antigen heavy chain. It was suggested that anti-β₂m antibody in sera from either patients or healthy controls might be directed mainly against free β₂m. The relationship between the anti-β₂m antibody and anti-lymphocytotoxic antibody found in those patients is discussed.