title: Accumulation of PHA granules in Cupriavidus necator as seen by confocal fluorescence microscopy.
abstract: Many bacteria are capable of accumulating intracellular granules of polyhydroxyalkanoates (PHA). In this work, we developed confocal microscopy analysis of bacterial cells to study changes in the diameters of cells as well as PHA granules during growth and PHA accumulation in the bacterium Cupriavidus necator H16 (formerly Ralstonia eutropha). The cell envelope was stained by DiD(®) fluorescent probe and PHA granules by Nile Red. Signals from both probes were separated based on their spectral and fluorescence life-time properties. During growth and PHA accumulation, bacterial cells increased their length but the width of the cells remained constant. The volume fraction of PHA granules in cells increased during PHA accumulation, nevertheless, its value did not exceed 40 vol. % regardless of the PHA weight content. It seems that bacterial cultures lengthen the cells in order to control the PHA volume portion. However, since similar changes in cell length were also observed in a PHA non-accumulating mutant, it seems that there is no direct control mechanism, which regulates the prolongation of the cells with respect to PHA granules volume. It is more likely that PHA biosynthesis and the length of cells are influenced by the same external stimuli such as nutrient limitation.
authors.affiliation: Materials Research Centre, Brno University of Technology, Purkynova 118, 612 00 Brno, Czech Republic.
authors.forename: Filip
authors.initials: F
authors.lastname: Mravec
authors.affiliation: Materials Research Centre, Brno University of Technology, Purkynova 118, 612 00 Brno, Czech Republic Stana.O@seznam.cz.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Obruca
authors.affiliation: Institute of Scientific Instruments, The Czech Academy of Sciences, v.v.i., Kralovopolska 147, 612 64 Brno, Czech Republic.
authors.forename: Vladislav
authors.initials: V
authors.lastname: Krzyzanek
authors.affiliation: Materials Research Centre, Brno University of Technology, Purkynova 118, 612 00 Brno, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Sedlacek
authors.affiliation: Institute of Scientific Instruments, The Czech Academy of Sciences, v.v.i., Kralovopolska 147, 612 64 Brno, Czech Republic.
authors.forename: Kamila
authors.initials: K
authors.lastname: Hrubanova
authors.affiliation: Institute of Scientific Instruments, The Czech Academy of Sciences, v.v.i., Kralovopolska 147, 612 64 Brno, Czech Republic.
authors.forename: Ota
authors.initials: O
authors.lastname: Samek
authors.affiliation: Materials Research Centre, Brno University of Technology, Purkynova 118, 612 00 Brno, Czech Republic.
authors.forename: Dan
authors.initials: D
authors.lastname: Kucera
authors.affiliation: Materials Research Centre, Brno University of Technology, Purkynova 118, 612 00 Brno, Czech Republic.
authors.forename: Pavla
authors.initials: P
authors.lastname: Benesova
authors.affiliation: Biology Centre, The Czech Academy of Sciences, v.v.i., Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Nebesarova
mesh_terms: D020118:Cupriavidus necator / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure*; D003594:Cytoplasmic Granules / Q000378:metabolism / Q000648:ultrastructure*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D054813:Polyhydroxyalkanoates / Q000737:chemistry / Q000378:metabolism*
chemical_list: D054813:Polyhydroxyalkanoates
keywords: Polyhydroxyalkanoates; bacterial cell diameters; confocal fluorescence microscopy; intracellular granules