Biomedical subjects

T Leustek

Publications and source records attributed to T Leustek.

39 records · Page 3Linked to original sources

PubMed1989

A member of the Hsp70 family is localized in mitochondria and resembles Escherichia coli DnaK.

A 71-kDa protein (P71) with properties similar to those of the Escherichia coli heat shock protein DnaK has been found in extracts of HeLa cells. P71 was copurified by ATP-agarose affinity chromatography with three additional proteins of the Hsp70 family. Of these proteins, only P71 crossreacted strongly with antiserum raised against purified DnaK, and both DnaK and P71 could be phosphorylated in vitro with [gamma-32]ATP in a reaction that was markedly stimulated by Ca2+. In HeLa cells, P71 was found to be concentrated in mitochondria. A protein similar to P71 was also found in calf liver and yeast mitochondria.

Calcium↗

PubMed1988

The influence of glutamine on growth and viability of cell suspension cultures of Douglas-fir after exposure to polyethylene glycol.

The response of cell cultures of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to osmotic stress was studied by measuring cell growth and viability after exposure to polyethylene glycol (PEG) (M(r) 6000-8000). Growth of cells inoculated in a medium containing 10% PEG was slightly inhibited, whereas growth in a medium containing 15% PEG was severely inhibited. Cells grown for 6 days in nutrient medium and then subcultured in a medium containing 15% PEG to induce water stress showed high viabilities, whereas cells grown for longer than 6 days before exposure to PEG showed decreased viabilities after subculture. Cells grown in medium containing 30 mM glutamine were significantly more resistant to PEG-induced water stress, as measured by viability, than cells grown in medium without glutamine.

Journal Article↗

PubMed1988

Regulation of ribulose bisphosphate carboxylase expression in Rhodospirillum rubrum: characteristics of mRNA synthesized in vivo and in vitro.

The synthesis of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) in Rhodospirillum rubrum was regulated by the CO2 concentration in the culture medium. The specific activity of RuBPCase in cells grown photolithotrophically in low concentrations of CO2 (1.5%) was five to ten times higher than that in cultures grown at high concentrations of CO2 (10%). Increased enzyme activity was reflected by an increase in both RuBPCase mRNA and RuBPCase protein. RuBPCase expression was also studied in vitro with a plasmid-borne genomic clone (pRR117) as the template in a partially defined Escherichia coli system containing either E. coli or R. rubrum RNA polymerase. With both enzymes there was excellent synthesis of RuBPCase mRNA, but no significant synthesis of RuBPCase was detected. The promoter region of the RuBPCase gene was sequenced, and mRNA start sites were mapped. A single major in vivo transcriptional start site was detected in RuBPCase mRNA extracted from R. rubrum. However, transcripts synthesized from pRR117 in vitro or from E. coli transformed with pRR117 started at upstream sites that were different from the in vivo transcription site. Two major features of the RuBPCase promoter region are three 6-base-pair direct repeats and a 31-base-pair region of dyad symmetry.

Base Sequence↗