Cellular Protein Profiles Research Articles

Heterogeneity in the cellular protein profiles ofClostridium botulinum types A and B

Profiles of cellular proteins from 11 type A and 9 type B strains ofClostridium botulinum were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cellular protein profiles exhibited considerable heterogeneity among strains of the same biotype, as well as among strains of different biotypes. This study also demonstrated the reliability and usefulness of this rapid and inexpensive procedure to determine the variation which may occur amongC. botulinum and related species.

Identification of a cadmium-binding protein from a cadmium-resistant variant of human lymphoblastoid cells (WI-L2)

Cadmium-binding protein synthesis and induction by cadmium chloride were studied in the human lymphoblastoid cell line WI-L2. Lymphoblasts were adapted to growth in 5 μM cadmium chloride (Cd r) and these cells were 2.5-fold more resistant to cadmium than the parental line. There was no difference in the cellular protein profile between the parental line and lymphoblasts grown for a short period, less than 10 days, in cadmium chloride as measured by [ 35S]cysteine labelling and SDS-polyacrylamide gel electrophoresis. A basal level of cadmium binding protein was apparent, however, by gel filtration. The Cd r lymphoblasts were found to synthesize a substantial amount of cadmium-binding protein, approximately 25-fold more than the parental line. The cadmium-binding protein has the following properties which are consistent with its being a metallothionein: (1) [ 35S]Cysteine-labelled protein eluted at a V e V o = 2.1 on a Sephadex G-75 column; (2) the molecular weight was estimated as 11 kDa on 7–17% SDS polyacrylamide gels; (3) the protein was heat-stable; (4) the unlabelled protein bound 109Cd 2+.