Glucose Degradation, Molar Growth Yields, and Evidence for Oxidative Phosphorylation in Streptococcus agalactiae

Abstract

In a complex medium with the energy source as the limiting nutrient factor and under anaerobic growth conditions, Streptococcus agalactiae fermented 75% of the glucose to lactic acid and the remainder to acetic and formic acids and ethanol. By using the adenosine triphosphate (ATP) yield constant of 10.5, the molar growth yield suggested 2 moles of ATP per mole of glucose from substrate level phosphorylation. Under similar growth conditions, pyruvate was fermented 25% to lactic acid, and the remainder was fermented to acetic and formic acids. The molar growth yield suggested 0.75 mole of ATP per mole of pyruvate from substrate level phosphorylation. Under aerobic growth conditions about 1 mole of oxygen was consumed per mole of glucose; about onethird of the glucose was converted to lactic acid and the remainder to acetic acid, acetoin, and carbon dioxide. Molar growth yields indicated 5 moles of ATP per mole of glucose. Estimates based on products of glucose degradation suggested that about one-half of the ATP was derived from substrate level phosphorylation and one-half from oxidative phosphorylation. Addition of 0.5 M 2,4-dinitrophenol reduced the growth yield to that occurring in the absence of oxygen. Aerobic pyruvate degradation resulted in 30% of the substrate becoming reduced to lactic acid and the remainder being converted to acetic acid and carbon dioxide, with small amounts of formic acid and acetoin. The molar growth yields and products found suggested that 0.70 mole of ATP per mole of pyruvate resulted from substrate level phosphorylation and 0.4 mole per mole of pyruvate resulted from oxidative phosphorylation.Crude cell-free extracts of Streptococcus agalactiae possess a reduced nicotinamide adenine dinucleotide (NADH) oxidase. The oxidase activity was enhanced considerably when the cells were grown under aerobic conditions (11). To evaluate the energy value of the NADH oxidase pathway, adenosine triphosphate (ATP) formation during NADH oxidation was measured with crude cell-free extracts (12). The results obtained suggested that oxidative phosphorylation occurred. The yield of ATP was low, and synthesis could be prevented by exclusion of 02 or by the use of respiratory poisons. It seemed desirable to confirm the results by an in vivo method. By a comparison of cellular yields per mole of substrate used under aerobic and anaerobic growth conditions, a more reliable measure of the energy value of the oxidative metabolic pathway should be obtainable. Bauchop and 96

Genome sequence of Streptococcus agalactiae, a pathogen causing invasive neonatal disease

“…It is conceivable that S. agalactiae can utilize external sources of haem although the corresponding transporters were not identified. As deduced from the genome sequence, S. agalactiae is able to ferment different carbon sources to multiple by‐products, such as lactate, acetate, ethanol, formate or acetoin, which is in agreement with the study of by‐product synthesis during glucose degradation by S. agalactiae ( Mickelson, 1972 ). It is worth noting that the bioenergetic metabolism of S. agalactiae is more related to that of L. lactis than to that of S. pyogenes or S. pneumoniae .…”

“…Streptococcus agalactiae is able to synthesize ATP by oxidative phosphorylation ( Mickelson, 1972 ). Analysis of the genome sequence confirms this result as we identified the structural genes for the cytochrome bd terminal quinol oxidase (gbs1784‐gbs1787).…”

Respiration metabolism of Group B Streptococcus is activated by environmental haem and quinone and contributes to virulence

“…We therefore tested the capacity of exogenous haem and quinone sources, haemin and menaquinone, to generate a functional respiratory chain in GBS strain NEM316 (Table 1). Two effects were observed: first, while aeration alone had a slight positive effect on GBS growth compared with that under static condition, as reported (Mickelson, 1972), addition of both haemin and menaquinone to aerated cultures produced a further increase in biomass. The increase was about twofold, as determined by cell dry weight (1.1 ± 0.1 mg for static, 1.4 ± 0.1 mg for aerobic and 2.1 ± 0.1 mg for aerobic plus quinone and haem, per millilitre of culture).…”

“…enzymes for quinone biosynthesis and for electron transfer from cytoplasmic substrates to quinone, were identified in both Lactococci and Enterococci (Winstedt et al ., 2000; Huycke et al ., 2001; R. Rezaïki, A. Gruss and P. Gaudu, in preparation). In contrast, while aeration itself seemed to improve GBS growth (Mickelson, 1967; 1972), efforts to turn up cytochrome‐like oxidases failed in GBS, and an exogenous haem source did not stimulate respiratory activity (Ritchey and Seely, 1976).…”

Salmonella enterica serovar Typhimurium sseK3 induces apoptosis and enhances glycolysis in macrophages

“…Pyruvic acid could enter the TCA cycle and be completely oxidized in aerobic conditions, or could become lactic acid under anaerobic conditions [46,47]. HIF-1α could prevent the production of ATP and thus regulate the glycolysis of mouse granulosa cells [48].…”