RT Journal Article SR Electronic(1) A1 Smeraldi, Carla A1 Berardi, Enrico A1 Porro, DaniloYR 1994 T1 Monitoring of peroxisome induction and degradation by flow cytometric analysis of Hansenula polymorphacells grown in methanol and glucose media: cell volume, refractive index and FITC retention JF Microbiology, VO 140 IS 11 SP 3161 OP 3166 DO https://doi.org/10.1099/13500872-140-11-3161 PB Microbiology Society, SN 1465-2080, AB Cell refractive index has been used to monitor peroxisome behaviour in the yeast Hansenula polymorphaby means of flow cytometry. Peroxisomes are inducible organelles which may occupy a large fraction of the cell volume when yeast cells are growing in methanol media. These organelles harbour a catalase that decomposes the hydrogen peroxide produced in methanol oxidation by alcohol oxidase, a peroxisomal enzyme whose subunits are arranged to form a regular crystalloid. Peroxisomes undergo a degradation process mediated by vacuoles whenever they and their enzymes become metabolically redundant (e.g. during growth on glucose). Flow cytometric analyses of side scattered light (depending on cell volume, morphology and structure) and fluorescein isothiocyanate retention (due to the vacuole) were made on two wild-type strains of H. polymorphaduring exponential growth in glucose and methanol media and during nutritional shifts from one carbon source to the other. The same parameters were also analysed for a mutant strain only partially repressed by glucose. We show that both the parameters are substrate-dependent and appear to reflect peroxisome development in the cells. The data reported correlate well with the known cytological and biochemical data, showing the possibility of using flow cytometry, a fast and sensitive technique, to analyse the dynamics of peroxisome proliferation and degradation in response to environmental as well as genetic factors., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-140-11-3161