title: [Morphological and biochemical changes of Microcystis aeruginosa PCC7806 subjected to dark and oxygen limitation].
abstract: OBJECTIVE
  To explore the mechanism of cell death in Microcystis aeruginosa PCC 7806.
  
  
  METHODS
  According to the water environment of the later period of algal bloom, M. aeruginosa PCC 7806 was treat with dark and O2 limitation. We observed the morphological changes using transmission electron microscope (TEM) and detected the reactive oxygen species (ROS) activity and Caspase3 activity in M. aeruginosa PCC7806 subjected to dark and O2 limitation. DNA status was also examined with the methods of Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) and agarose gel electrophoresis.
  
  
  RESULTS
  Massive algae cell died after 48 h treatment under dark and O2 limitation. During cell death process, we observed some changes of cell organelles including ribosomes and thylakoids disorganization, cytoplasmic vacuolation, nucleoplasm diffusion and plasmolysis in M. aeruginosa PCC7806 subjected to darkness and O2 limitation. Meanwhile, we found that increased ROS reactivity and capase 3 activity were related to the cell death process of M. aeruginosa. DNA breakage and fragmentation were proved by TUNEL staining and agarose gel electrophoresis during cell death process.
  
  
  CONCLUSIONS
  All results showed that cell death with characteristics similar to eukaryotic programmed cell death could be induced in M. aeruginosa PCC 7806 after treatment with darkness and O2 limitation. Therefore, we suggested that the mechanism of cell death are conserved during evolution according to the characteristics of cell death shared between eukaryotes and Microcystis.
authors.affiliation: State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, China. Lisha219@sina.com
authors.forename: Lisha
authors.initials: L
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Juan
authors.initials: J
authors.lastname: Wu
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
mesh_terms: D053148:Caspase 3 / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D003624:Darkness; D006863:Hydrogen-Ion Concentration; D046931:Microcystis / Q000378:metabolism* / Q000648:ultrastructure; D010100:Oxygen / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D004247:DNA; D053148:Caspase 3; D010100:Oxygen