title: Reorganization of Azospirillum brasilense cell membrane is mediated by lipid composition adjustment to maintain optimal fluidity during water deficit.
abstract: OBJECTIVE
  We study the Azospirillum brasilense tolerance to water deficit and the dynamics of adaptive process at the level of the membrane.
  
  
  RESULTS
  Azospirillum brasilense was exposed to polyethylene glycol (PEG) growth and PEG shock. Tolerance, phospholipids and fatty acid (FA) composition and membrane fluidity were determined. Azospirillum brasilense was able to grow in the presence of PEG; however, its viability was reduced. Cells grown with PEG showed membrane fluidity similar to those grown without, the lipid composition was modified, increasing phosphatidylcholine and decreasing phosphatidylethanolamine amounts. The unsaturation FAs degree was reduced. The dynamics of the adaptive response revealed a decrease in fluidity 20 min after the addition of PEG, indicating that the PEG has a fluidizing effect on the hydrophobic region of the cell membrane. Fluidity returned to initial values after 60 min of PEG exposure.
  
  
  CONCLUSIONS
  Azospirillum brasilense is able to perceive osmotic changes by changing the membrane fluidity. This effect is offset by changes in the composition of membrane phospholipid and FA, contributing to the homeostasis of membrane fluidity under water deficit.
  
  
  CONCLUSIONS
  This knowledge can be used to develop new Azospirillum brasilense formulations showing an adapted membrane to water deficit.
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: A B
authors.initials: AB
authors.lastname: Cesari
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: N S
authors.initials: NS
authors.lastname: Paulucci
authors.affiliation: Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: M A
authors.initials: MA
authors.lastname: Biasutti
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: Y B
authors.initials: YB
authors.lastname: Reguera
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: L A
authors.initials: LA
authors.lastname: Gallarato
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: C
authors.initials: C
authors.lastname: Kilmurray
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
authors.forename: M S
authors.initials: MS
authors.lastname: Dardanelli
mesh_terms: D015806:Azospirillum brasilense / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D008560:Membrane Fluidity; D010743:Phospholipids / Q000032:analysis / Q000378:metabolism; D014867:Water / Q000032:analysis / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D010743:Phospholipids; D014867:Water
keywords: Azospirillum brasilense; fatty acids; membrane fluidity; phospholipids; response; water deficit