The cytochrome composition of the meat spoilage bacterium Brochothrix thermosphacta: identification of cytochrome a 3- and d-type terminal oxidases under various conditions

Abstract

Brochothrix thermosphacta, grown in batch culture in a yeast-dextrose broth, at temperatures from 30 degrees C to 10 degrees C, contained diverse membrane-bound respiratory cytochromes. Under conditions of moderate aeration, cytochromes of the a-, b- and d-type were detected at all growth temperatures, but the proportions changed as a function of temperature, with the spectra of cells grown at 10 or 15 degrees C being dominated by a-type cytochrome(s). Cytochrome a3 was detected by its reactions with CO and cyanide in cells from all growth conditions. An additional cytochrome a, which was not cyanide-reactive, was also detected, suggesting the presence of an aa3 oxidase complex. Cytochrome d was cyanide- and CO-reactive, but not detectable in photodissociation spectra, presumably because of the very rapid recombination of CO at the sub-zero temperatures used. Decreasing the oxygen transfer rates to batch cultures resulted in enhanced expression of cytochrome d and changed the proportion of the aa3-type oxidase that could be attributed to ligand-binding cytochrome a3; at the lowest oxygen transfer rates, no cytochrome a was detected, suggesting the presence of a cytochrome ba3 terminal oxidase complex. Intact cells showed no evidence of a c-type cytochrome and no haem C was detected in membrane preparations. After growth at 10 degrees C, the cytochrome composition of B. campestris was essentially identical to that of B. thermosphacta. The multiplicity of putative terminal oxidases in B. thermosphacta is discussed.

Role of an Inducible Single-Domain Hemoglobin in Mediating Resistance to Nitric Oxide and Nitrosative Stress in Campylobacter jejuni and Campylobacter coli

“…The possibility that the expression of Cgb was regulated by oxygen was checked by growing C. jejuni in a microaerobic atmosphere, but at different volumes (5, 10, 25, 35, and 45 ml) of medium in 50-ml conical flasks. Such variation of culture volume has been shown previously to be reflected in the oxygen transfer rate (K L a) from the gas to liquid phase (21). Since Cgb was present at a very low level under noninduced conditions, higher amounts of soluble protein (45 g) were used for Western blotting.…”

Regulation of expression of the cyanide-insensitive terminal oxidase in Pseudomonas aeruginosa

“…This was achieved by using identical 250 ml flasks, shaking at 200 r.p.m., but altering the medium volume. The k L a values for medium volumes of 25 ml (high), 75 ml (medium), and 150 ml (low) were estimated by the sulphite oxidation method (Pirt, 1975;Ruchti et al, 1985;Gil et al, 1992;D'Mello et al, 1994). Fig.…”

Expression and Content of Terminal Oxidases in Azotobacter Vinelandii Grown with Excess NH4+ are Modulated by O2 Supply

“…Cytochrome 6d levels are also elevated at low oxygen tensions in the diazotroph Klebsiella pneumoniae (Smith et al, 1990). In contrast, the level of cytochrome bd in N,-fixing A. vinelandii oxidase is greatest under high aeration (Drozd & Postgate, 1970;Jones et al, 1973;Haaker & Veeger, 1976), although one report describes the reverse situation (Ackrell & Jones, 1971). Accompanying the increase in the cytochrome bd level is a loss of energy conservation at ' Site I' (Jones et al, 1973).…”