Influence of stress factors on the intrinsic fluorescence of Cupriavidus necator

abstract

English

This contribution focuses on autofluorescence of flavins in gram-negative bacteria Cupriavidus necator H16 and its mutant strain PHB-4. These bacteria are known for their production of polyhydroxyalkanoates. It is necessary to know suitable conditions for the production of these polymers. Some stressors can positively affect the production of PHA granules, but it is also necessary to map the behavior of cells in order to grow and multiply. The main method was fluorescence lifetime imaging microscopy and subsequent analysis by TCSPC. At the beginning, the cells were testing without stress response. The ratio of short fluorescence lifetime to long autofluorescence lifetime was taken as an indicator of the external influence. Autofluorescence of the supernatant was measured; it was found that the relative amplitude of long lifetime was multiple times higher than in the cell. The cells were affected by the amount of dissolved oxygen in the production medium, by differently concentrated hydrogen peroxide and by substances that directly influence on bacterial respiratory chain, like sodium azide and antimycin A. Of all of these stress factors, the antibiotic had the least influence on the ratio of the short and long fluorescence lifetime.

bacteria; fluorescence microscopy; FLIM; autofluorescence; TCSPC;

MARKOVÁ, K.; MRAVEC, F.; OBRUČA, S.

11. 9. 2022

Sweden MEETX AB

Gothenburg

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