Regulation of energy source metabolism in streptococci

Neijssel, Oense M.; Snoep, Jacky L.; Mattos, M. Joost Teixeira de

doi:10.1046/j.1365-2672.83.s1.2.x

Cited by 32 publications

(28 citation statements)

References 2 publications

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“…Glucose catabolization yields ATP and pyruvate through intermediary carbohydrate metabolism. Pyruvate is ultimately catabolized by enterococci to CO 2 and acetate under aerobic growth conditions and to CO 2 and lactate under microaerobic growth conditions (19,25). Accordingly, on depletion of glucose during the exponential-growth phase (4 h), we observed a rapid increase in acetate concentrations (Fig.…”

Section: Vol 47 2009 Enterococcus Small-colony Variants 2805mentioning

confidence: 73%

“…This could be due to regulation of key enzymes involved in the production/utilization of pyruvate, which might act as metabolic branch points between the normal and SCV phenotypes under oxidative growth conditions. Some of these enzymes, for example, PflB/EF1613 (pyruvate-formate lyase, oxygen sensitive), PDH (pyruvate dehydrogenase complex, regulated by the NADH/NAD ϩ ratio) (19,25), and SdhA/ EF0098 (L-serine dehydratase, oxygen sensitive due to the presence of an iron-sulfur cluster protein) (8), are interesting candidates, and their involvement in the regulation of the E. faecalis SCV phenotype will be investigated in the future.…”

Section: Discussionmentioning

confidence: 99%

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Characterization of Clinical Enterococcus faecalis Small-Colony Variants

et al. 2009

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In this report, we present a clinical case of chronic aortic valve endocarditis caused by Enterococcus faecalis small-colony variants (SCVs), with ensuing characterization of the SCV phenotype in comparison to the clonally related normal phenotype with respect to alterations in microscopic and ultrastructural morphology, growth behavior, and metabolic pathways. In contrast to the normal phenotype, light and electron microscopy of the Enterococcus SCVs demonstrated the presence of heterogeneous cells of different sizes with aberrant shapes. Furthermore, SCVs showed excessive production of an intercellular substance and alterations in cell division displayed by a thick, coarse cell wall and incomplete, branched, and multiple cross walls without obvious cell separation. In addition, empty "ghost" cells were visible. In growth experiments, SCVs displayed an extended lag phase with delayed entrance into the stationary phase. Interestingly, SCV cells growing under aerobic conditions did not attain the growth and viability of the normal phenotype or those of SCVs growing under microaerobic conditions, suggesting impaired growth behavior and enhanced vulnerability in the presence of oxygen. By metabolite analysis, SCVs failed to produce significant amounts of acetate or lactate under aerobic growth conditions but were able to produce lactate under microaerobic growth conditions, implicating the induction of a fermentative metabolism. In conclusion, the observed structural alterations and changes in the cellular growth and metabolic pathways facilitated the survival of Enterococcus SCVs under microaerobic conditions in vitro and thus presumably in vivo during endocarditis.Small-colony variants (SCVs) constitute a slow-growing subpopulation of bacteria with distinctive phenotypic and pathogenic characteristics. Since their first description in 1910, SCVs have been described in a wide range of gram-positive and gram-negative bacterial species, including Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, and Burkholderia cepacia (23). Generally, SCVs display a small colony size, a low growth rate, and atypical colony morphology (16). Biochemical characteristics of SCVs include a deficiency in electron transport or in thymidine biosynthesis (4, 23). SCVs are specialized for intracellular persistence in host cells and have been shown to be associated with persistent and recurrent infections, such as osteomyelitis, arthritis, abscesses, and respiratory infections, in humans (23). Reduced susceptibility to antimicrobial substances relative to that of their normal counterparts (26), which are often isolated simultaneously, restrict the therapeutic options for SCV infections. While SCVs of staphylococci, especially those of S. aureus, are intensively studied for their morphological, ultrastructural, metabolic, and growth characteristics (3,4,(15)(16)(17)22), little is known about the SCVs of Enterococcus species. Their occurrence in a patient with endocarditis (13) an...

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Section: Vol 47 2009 Enterococcus Small-colony Variants 2805mentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Characterization of Clinical Enterococcus faecalis Small-Colony Variants

et al. 2009

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“…Oxidative conditions stimulated the production of volatile sulphur compounds such as dimethyl sulphide, and aldehydes such as acetaldehyde [49]. In the presence of oxygen, the oxidative decarboxylation of 2-acetolactate and 2-aceto-hydroxybutyrate to diacetyl and pentane-2,3-dione respectively was also favoured [40,42,44,52]. For diacetyl, our result can be explained by the fact that in anaerobic conditions lactic acid bacteria dehydrogenate the NADH produced during glycolysis via lactate dehydrogenase (LDH) activity.…”

Section: Impact On Aroma Biosynthesis By Lactic Acid Bacteriamentioning

confidence: 68%

“…These diketones are produced by decarboxylation of their precursors, 2-acetolactate and 2-aceto-hydroxybutyrate [39]. These compounds are thermally unstable and in the presence of oxygen are converted into their corresponding diketones [40,41]. Moreover, during storage at 4 °C, the concentration of the two diketones increases slightly [41] due to the basal metabolic activity of the bacteria.…”

Section: A Look At Yoghurt Aroma Compoundsmentioning

confidence: 99%

“…Neijssel et al [40] showed that the distribution of carbon flux from pyruvate depended on the NADH / NAD + ratio, intracellular redox potential or the concentration of metabolites and particularly that of pyruvate. Finally, the authors suggested adding air or oxygen to milk in order to increase the amount of diacetyl in cheese [45].…”

Section: A Look At Yoghurt Aroma Compoundsmentioning

confidence: 99%

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Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products

Martin¹,

Ebel²,

Rojas³

et al. 2013

Lactic Acid Bacteria - R &Amp; D for Food, Health and Livestock Purposes

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Influence of the pH on (open) mixed culture fermentation of glucose: A chemostat study

Temudo

Kleerebezem

Loosdrecht

2007

Biotech & Bioengineering

214

192

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Catabolic products from anaerobic fermentation processes are potentially of industrial interest. The volatile fatty acids and alcohols produced can be used as building blocks in chemical processes or applied directly as substrates in a mixed culture process to produce bioplastics. Development of such applications requires a predictable and controllable product spectrum of the fermentation process. The aim of the research described in this paper was (i) to investigate the product spectrum of an open mixed culture fermentation (MCF) process as a function of the pH, using glucose as substrate, and (ii) to relate the product spectrum obtained to generalized biochemical and thermodynamic considerations. A chemostat was operated under carbon and energy limitation in order to investigate the pH effect on the product spectrum in a MCF process. A transition from CO(2)/H(2) production at lower pH values to formate production at higher pH values was observed. The ratio of CO(2)/H(2) versus formate production was found to be related to the thermodynamics of formate dehydrogenation to CO(2)/H(2). This transition was associated with a shift in the catabolic products, from butyrate and acetate to ethanol and acetate, likely due to a decrease in the oxidation state of the electron carriers in the cell. The product spectrum of the MCF process as a function of the pH could largely be explained using general biochemical considerations.

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Regulation of energy source metabolism in streptococci

Cited by 32 publications

References 2 publications

Characterization of Clinical Enterococcus faecalis Small-Colony Variants

Characterization of Clinical Enterococcus faecalis Small-Colony Variants

Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products

Influence of the pH on (open) mixed culture fermentation of glucose: A chemostat study

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