Effect of Al(III) on surface properties of Bifidobacterium thermophilum as a function of temperature.
The effects of Al(III) on surface properties and lactate accumulation by Bifidobacterium thermophilum were investigated. Bacteria were treated with Al(III) at 37 degrees C and 4 degrees C, then exposed to free radicals or nisin. When exposed to Al(III) at 37 degrees C, the organism exhibited spreading on hydrophobic surfaces and showed high susceptibility to free-radical alteration as indicated by Fe(III) binding, but showed little effect on lactate production in the presence or absence of nisin, even after washing with 2 mM EDTA. At 4 degrees C, there was no increased surface spreading or binding of Fe(III), but protection against nisin action was present. This, however, was abolished after washing with EDTA. It was concluded that membrane fluidity is required to affect membrane lipid rearrangement, resulting in surface spreading and increased susceptibility to peroxidation, whereas only loose binding of Al(III) to membrane surfaces is sufficient to prevent transmembrane channel formation by nisin.
Kot
Eva
E
Department of Biochemistry, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, USA.
Bezkorovainy
Anatoly
A
D000535:Aluminum / Q000494:pharmacology*; D001644:Bifidobacterium / Q000187:drug effects* / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions; D007501:Iron / Q000378:metabolism; D019344:Lactic Acid / Q000096:biosynthesis; D009561:Nisin / Q000494:pharmacology; D013696:Temperature
D009561:Nisin; D019344:Lactic Acid; D004492:Edetic Acid; D000535:Aluminum; D007501:Iron