A high-resolution reference map for cytoplasmic and membrane-associated proteins of Corynebacterium glutamicum.

We present a high-resolution reference map for soluble proteins obtained from Corynebacterium glutamicum cells grown in glucose minimal medium. The analysis window covers the pl range from 4-6 and the molecular mass range from 5-100 kDa. Using overlapping narrow immobilized pH gradients for isoelectric focusing, 970 protein spots were detected after second-dimensional separation on SDS-polyacrylamide gels and colloidal Coomassie-staining. By tryptic peptide mass fingerprinting 169 protein spots were identified, representing 152 different proteins including many enzymes involved in central metabolism (18), amino acid biosynthesis (24) and nucleotide biosynthesis (11). Thirty-five of the identified proteins have no known function. A comparison of the observed and the expected physicochemical properties of the identified proteins indicated that nine proteins were covalently modified, since variants with apparently identical molecular mass, but differing pl were detected. The N-termini of eight proteins were determined by post-source decay (PSD) analysis of selected peptides. In addition to the soluble proteins, a map of the membrane-bound proteins within the pl range 4-7 is presented, which contains 660 protein spots, 22 of which were identified, representing 13 different proteins.

Observations with Thalassiosira rotula (Meunier) on the toxicity and accumulation of cadmium and nickel.

Cadmium and nickel toxicity thresholds based on generation time, maximum cell density, and chain length as toxicity indicators were evaluated from batch cultures of the marine diatom Thalassiosira rotula in nutrient-enriched seawater as substrate. Nickel toxicity is about an order of magnitude or more higher than cadmium toxicity. The toxicity thresholds decrease with increasing illumination and are not significantly affected by 10 mumol/liter EDTA. From the metal accumulation determined by voltammetry average maximum uptakes of 90 micrograms Ni/g DW and 600 micrograms Cd/g DW were determined.