Metabolic flux response to salt-induced stress in the halotolerant yeast Debaryomyces hansenii.
The toxic effect of NaCl and KCl on growth of the marine yeast Debaryomyces hansenii on glucose or glycerol was studied. Above a threshold value, both salts reduced the specific growth rate, specific glucose and glycerol respiration rates and specific glucose fermentation rate, as well as biomass yields. The exponential inhibition constant, k, and minimum toxic concentration, Cmin were similar for all physiological parameters assayed. The effect of either salt on the specific activity of several glycolytic enzymes showed a similar inhibition pattern, although at much lower salt concentrations compared with the physiological parameters. In agreement with published results on glycerol phosphate dehydrogenase stimulation by salt, we present evidence that a general glycolytic flux deviation could occur naturally during salt stress, due to the intrinsic sensitivity of the glycolytic enzymes to intracellular ion concentrations.
Neves
M Luisa
ML
Departamento de Biologia da Universidade do Minho, Campus de Gualtar 4709 Braga Codex, Portugal.
Oliveira
Rui P
RP
Departamento de Biologia da Universidade do Minho, Campus de Gualtar 4709 Braga Codex, Portugal.
Lucas
Cândida M
CM
Departamento de Biologia da Universidade do Minho, Campus de Gualtar 4709 Braga Codex, Portugal.
D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006019:Glycolysis; D008386:Marine Biology; D010101:Oxygen Consumption; D011189:Potassium Chloride / Q000633:toxicity; D004718:Saccharomycetales / Q000187:drug effects / Q000502:physiology*; D012965:Sodium Chloride / Q000633:toxicity; D014871:Water Microbiology; D014882:Water-Electrolyte Balance
D012965:Sodium Chloride; D011189:Potassium Chloride; D005947:Glucose; D005990:Glycerol