Ultra High Pressure Treatment of Streptomyces sp. R61

摘要

At present, ultra high pressure (UHP) is proposed to be used for food preservation. For the experiments the strain Streptomyces sp. R61 was used. The purpose of the work was to test: ultrastructural changes of UHP treated cells, UHP killing presusre, UHP mode of killing, mutagenic effect of UHP. The hyphal cells were treated separately at 100, 200, 300, 400, 500 MPa, (exponential phase) for 10 min. The ultrathin sections were examined under a transmission electron microscope. A Prokaryote ultrastructure was observed. In comparison with not UHP treated cells in the cells after 100 MPa treatment no ultrastructural changes could be seen. After UHP treatment some of the cells (about 20percent, i.e. young cells and senescent cells) were disrupted showing a lack of cytoplasm. Other cells did not show ultrastructural changes. At 300-500 MPa in the not disrupted cells the ribosomes were crushed. Only a few colonies were grown on solid medium after 300 MPa. The colonies after 300 MPa did not show morphological changes. The second generation did not show a genetically diversified population. Ultra high killing pressure for the tested strain is 400 MPa. UHP mode of killing: disruption of young and senescent cells at 200-300 MPa, crushing of ribosomes of mature cells, disturbing the protein biosynthesis. No mutagenic effect of UHP was observed.