title: Humectant permeability influences growth and compatible solute uptake by Staphylococcus aureus subjected to osmotic stress.
abstract: The effects of different humectants (sodium chloride, sucrose, and glycerol) on the growth of and compatible solute (glycine betaine, proline, and carnitine) uptake by the osmotolerant foodborne pathogen Staphylococcus aureus were investigated. While growth in the presence of the impermeant humectants sodium chloride and sucrose induced the accumulation of proline and glycine betaine by cells, growth in the presence of the permeant humectant glycerol did not. When compatible solutes were omitted from low-water-activity media, growth was very poor in the presence of impermeant humectants. In contrast, the addition of compatible solutes had essentially no effect on growth when cells were grown in low-water-activity media containing glycerol as the humectant. Carnitine was found to accumulate to high intracellular levels in osmotically stressed cells when proline and glycine betaine were absent, making it a potentially important compatible solute for this organism.
authors.affiliation: Department of Food Science, The Pennsylvania State University, University Park 16802, USA.
authors.forename: Oddur
authors.initials: O
authors.lastname: Vilhelmsson
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Miller
mesh_terms: D001622:Betaine / Q000378:metabolism; D001693:Biological Transport, Active / Q000187:drug effects; D002855:Chromatography, Thin Layer; D003451:Cryoprotective Agents; D005990:Glycerol / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D010539:Permeability; D011156:Population Density; D011392:Proline / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000254:growth & development* / Q000378:metabolism; D013395:Sucrose / Q000494:pharmacology; D014867:Water / Q000378:metabolism
chemical_list: D003451:Cryoprotective Agents; D014867:Water; D001622:Betaine; D012965:Sodium Chloride; D013395:Sucrose; D011392:Proline; D005990:Glycerol