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Biomedical subjects

K Heller

Publications and source records attributed to K Heller.

At least 145 records · Page 8Linked to original sources
PubMed1978

Inhibition of protein synthesis in Streptococcus faecalis by ochratoxin A.

A non-competitive inhibition of binding of cAMP to bovine protein kinase by ochratoxin A (OTA) is shown. Preliminary evidence of a protein kinase in Streptococcus faecalis is presented. The cAMP stimulation of this kinase is also inhibited by OTA. At the lowest OTA concentrations, RNA and protein synthesis are inhibited in S. faecalis. The inhibition of RNA synthesis is secondary, as in the presence of chloramphenicol no inhibition occurs for 10 min after the addition of OTA. The synthesis but not the induction of beta-P-galactosidase is inhibited by OTA. The polysomes of S. faecalis are stabilized after addition of OTA, showing an inhibition of peptide elongation. The model of action of OTA in bacteria is discussed and it is concluded that inhibition of protein synthesis is the process which might be closest to the primary target of OTA.

Bacterial Proteins↗
PubMed1977

[Ureteric lesions in childhood (author's transl)].

Diagnosis in these cases is particularly difficult. By early intravenous pyelography the site of the injury can be located and presence and function of the contralateral kidney be proved.

Abdominal Injuries↗
PubMed1975

The inhibition of bacterial growth by ochratoxin A.

A series of bacterial species was examined for their sensitivity to ochratoxin A. Only grampositive bacteria could be inhibited, generally at a pH lower than 7.0. Bacillus subtilis did not show any reduction of growth rates in presence of ochratoxin A, but had a prolonged lag phase. With Staphylococcus pyogenes var. aureus and Streptococcus faecalis, a prolonged lag phase and a reduction of the growth rate was observed. Most sensitive was Streptococcus faecalis in the exponential-growth phase. The inhibition could be diminished by changing the pH to neutral, or by addition of yeast extract, tetrahydrofolate, or MgSO4. With MgSO4 a complete abolition of the inhibitory effect was achieved, but not with CaCl2. During growth inhibition, protein and RNA synthesis were reduced simultaneously, but not DNA synthesis. Even with the very high concentration of 1 mg/ml, no lethal effect was observed.

Aspergillus↗