title: The effect of different dissolved oxygen tensions on growth and enzyme activities of Campylobacter sputorum subspecies bubulus.
abstract: Campylobacter sputorum subspecies bubulus was grown in batch cultures in which the dissolved oxygen tension (d.o.t) was maintained at various constant levels. At a range of d.o.t. from 0.002 to 0.05 atm, which allowed good growth (mean generation time approximately 1.5 h), L-lactate was preferentially consumed before D-lactate. L-lactate oxidation was accompanied by equimolar acetate production during exponential growth. A value for YL-lactate (g dry weight bacteria per mol L-lactate) of 54 was determined. Net acetate production stopped when C. sputorum started to use D-lactate after consumption of L-lactate. When a culture growing exponentially at the expense of L-lactate was shifted from a d.o.t. of 0.02 atm to a d.o.t. of 0.15 atm, growth was impaired, and L-lactate consumption and corresponding acetate production diminished. This decrease correlated with a loss of lactate dehydrogenase activity after the shift. Campylobacter sputorum appeared to possess cytochromes of the b- and c-type and a carbon monoxide-binding pigment. Evidence is given that the principal site of oxygen damage is lactate dehydrogenase rather than the cytochrome chain.
mesh_terms: D000085:Acetates / Q000378:metabolism; D002167:Campylobacter / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D003580:Cytochromes / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*
chemical_list: D000085:Acetates; D003580:Cytochromes; D007773:Lactates; D010088:Oxidoreductases; D007770:L-Lactate Dehydrogenase; D010100:Oxygen