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High hydrostatic pressure (HHP) becomes more and more interesting for life science research, since it can be employed to inactivate various cells. To directly monitor "cells under pressure," the development of an optical high-pressure chamber is required. Therefore, an optical pressure chamber that can be used for up to 300 MPa was constructed. This chamber has already been described as a tool for in situ observation of dynamic changes of microscopic structures in bright field as well as phase contrast. In combination with an inverted microscope, we obtained brilliant microscopic color pictures with an optical resolution more than 0.56 microm. Here, we demonstrate the capabilities of the HHP cell, in combination with epifluorescence microscopy. Using a nonadherent human B-cell line (Raji, ATCC CCL 86), stained with the fluorescent dyes propidium iodide, Hoechst 33342, or dihexyloxacarbocyanine iodide, we were able to show that the system is suitable to perform fluorescence microscopic analyses, with pressures up to 300 MPa, with viable mammalian cells.

Dimethyl sulphide is a well characterized off-flavour in the brewing industry. The thermal re-creation of dimethyl sulphide by the decomposition of dimethyl sulphide precursor in standardized wort is measured using pressure-controlled boiling processes at different temperatures. The results are used for the calculation of decomposition speed constants and Arrhenius activation energies. Using these data the re-creation of dimethyl sulphide during the wort production processes can be calculated and thereby optimized.