Dynamics of pyruvate metabolism in Lactococcus lactis

Melchiorsen, Claus Rix; Jensen, Niels Bang Siemsen; Christensen, Bjarke Bak; Jokumsen, Kirsten Væver

doi:10.1002/bit.1117.abs

Cited by 22 publications

(31 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is interesting to note that the accumulation of glucose at pH 4?7 restores homolactic fermentation, as has been shown under chemostat conditions at high growth rates (Thomas et al, 1979). The regulation of pyruvate formate lyase (PFL) may contribute to this metabolic shift since this enzyme has been identified as a key enzyme under neutral conditions (Melchiorsen et al, 2001). Furthermore, PFL is known to be more sensitive to low pH than lactate dehydrogenase (Asanuma & Hino, 2000).…”

Section: Discussion Acid Stress Damagesmentioning

confidence: 99%

Transcriptional, translational and metabolic regulation of glycolysis in Lactococcus lactis subsp. cremoris MG 1363 grown in continuous acidic cultures

2003

View full text Add to dashboard Cite

The physiological behaviour of Lactococcus lactis subsp. cremoris MG 1363 was characterized in continuous culture under various acidic conditions (pH 4·7–6·6). Biomass yield was diminished in cultures with low pH and the energy dedicated to maintenance increased due to organic acid inhibition and cytoplasmic acidification. Under such acidic conditions, the specific rate of glucose consumption by the bacterium increased, thereby enhancing energy supply. This acceleration of glycolysis was regulated by both an increase in the concentrations of glycolytic enzymes (hierarchical regulation) and the specific modulation of enzyme activities (metabolic regulation). However, when the inhibitory effect of intracellular pH on enzyme activity was taken into account in the model of regulation, metabolite regulation was shown to be the dominant factor controlling pathway flux. The changes in glycolytic enzyme concentrations were not correlated directly to modifications in transcript concentrations. Analyses of the relative contribution of the phenomena controlling enzyme synthesis indicated that translational regulation had a major influence compared to transcriptional regulation. An increase in the translation efficiency was accompanied by an important decrease of total cellular RNA concentrations, confirming that the translation apparatus of L. lactis was optimized under acid stress conditions.

show abstract

Section: Discussion Acid Stress Damagesmentioning

confidence: 99%

Transcriptional, translational and metabolic regulation of glycolysis in Lactococcus lactis subsp. cremoris MG 1363 grown in continuous acidic cultures

2003

View full text Add to dashboard Cite

show abstract

“…pfl expression in other bacteria is known to be influenced by galactose and anaerobiosis (33,34). Indeed, in strain D39 in anaerobiosis, SPD0420 expression increased nearly ninefold in galactose relative to that for glucose-grown bacteria.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, in other lactic acid bacteria, low pH and excess supplies of energy reduced pfl mRNA levels, while the level of ldh mRNA increased (3). The regulation of PFL is allosterically controlled in L. lactis by the glycolytic intermediates fructose 1,6-bisphosphate, glyceraldehyde-3-phosphate (GAP), and dihydroxyacetone phosphate, which are strong inhibitors of PFL (33).…”

mentioning

confidence: 99%

Pyruvate Formate Lyase Is Required for Pneumococcal Fermentative Metabolism and Virulence

et al. 2009

View full text Add to dashboard Cite

Knowledge of the in vivo physiology and metabolism of Streptococcus pneumoniae is limited, even though pneumococci rely on efficient acquisition and metabolism of the host nutrients for growth and survival. Because the nutrient-limited, hypoxic host tissues favor mixed-acid fermentation, we studied the role of the pneumococcal pyruvate formate lyase (PFL), a key enzyme in mixed-acid fermentation, which is activated posttranslationally by PFL-activating enzyme (PFL-AE). Mutations were introduced to two putative pfl genes, SPD0235 and SPD0420, and two putative pflA genes, SPD0229 and SPD1774. End-product analysis showed that there was no formate, the main end product of the reaction catalyzed by PFL, produced by mutants defective in SPD0420 and SPD1774, indicating that SPD0420 codes for PFL and SPD1774 for putative PFL-AE. Expression of SPD0420 was elevated in galactose-containing medium in anaerobiosis compared to growth in glucose, and the mutation of SPD0420 resulted in the upregulation of fba and pyk, encoding, respectively, fructose 1,6-bisphosphate aldolase and pyruvate kinase, under the same conditions. In addition, an altered fatty acid composition was detected in SPD0420 and SPD1774 mutants. Mice infected intranasally with the SPD0420 and SPD1774 mutants survived significantly longer than the wild type-infected cohort, and bacteremia developed later in the mutant cohort than in the wild type-infected group. Furthermore, the numbers of CFU of the SPD0420 mutant were lower in the nasopharynx and the lungs after intranasal infection, and fewer numbers of mutant CFU than of wild-type CFU were recovered from blood specimens after intravenous infection. The results demonstrate that there is a direct link between pneumococcal fermentative metabolism and virulence.Streptococcus pneumoniae is the leading cause of pneumonia in children and adults, and it is a major cause of otitis media, meningitis, and septicemia (22). Despite considerable progress in pneumococcal vaccine development, the serotype specificity and the genomic plasticity of the pneumococcus will hamper its success (36). In addition, the increasing frequency of antibiotic resistance (14) makes it important to understand the mechanisms of pathogenesis of pneumococcal disease.Probably one of the most understudied fields of pneumococcal biology is that of how the pathogen generates its metabolic energy. The pneumococcus is strictly fermentative, and sugars are the major sources of energy for biosynthesis and growth (19,52). Therefore, in vivo fitness is determined to a large extent by the processes governed by sugar metabolism. Accumulating evidence suggests that there is a direct link between pneumococcal virulence and sugar metabolism (6,16,20,21,50). This is not limited to proteins involved in polysaccharide degradation, transport, and regulation (16, 31) but also includes those involved in redox metabolism, such as NADH oxidase (Nox) (6), and in pyruvate metabolism (42,50). For example, mutation of nox caused diminished virulence in a systemic infec...

show abstract

“…These organic acids were suggested to substitute the requirement of true hiochi-bacilli for acetate which is generally scarce in sake 41 . However, this hypothesis remains to be tested, since these organic acids are increasingly implicated in energy production in LAB 20,55,62,63,82,86 and presumably help LAB survive in inhospitable environments. Interestingly, it has been shown that the presence of ethanol in high concentrations considerably increases the thickness of the cell wall of true hiochi-bacilli.…”

Section: Unique Features Of Sake and Beer Spoilage Lab Ethanol Toleramentioning

confidence: 99%

Sake and Beer Spoilage Lactic Acid Bacteria - A Review

Suzuki

Asano

Iijima

et al. 2008

Journal of the Institute of Brewing

View full text Add to dashboard Cite

Japanese rice wine, sake, is a traditional alcoholic beverage in Japan. Similar to the case with beer, sake is known to be microbiologically stable and most microorganisms fail to grow in sake. This is principally due to its high ethanol concentration that reaches approximately 20% (v/v) in undiluted sake products and 15% (v/v) in finished products. Despite the high level of ethanol content, spoilage incidents occasionally occur in sake, due to the presence of highly ethanol-tolerant lactobacilli, known as hiochi-bacteria. Hiochi-bacteria are generally composed of two groups of lactobacilli, hiochi-lactobacilli and true hiochi-bacilli. The former group of lactobacilli is less ethanoland heat-tolerant, and therefore rarely poses a problem to sake products. In contrast, the true hiochi-bacilli exhibit extraordinarily high ethanol tolerance and cause spoilage incidents in sake, conferring acidity and off-flavors, such as diacetyl, in spoiled products. From a taxonomic standpoint, the true hiochi-bacilli mainly consist of two Lactobacillus species, L. fructivorans and L. homohiochi. The strains of true hiochi-bacilli prefer sake-like environments, and the presence of ethanol and mevalonic acid, in combination with low pH milieu, is essential or stimulatory for the growth of these bacteria. Interestingly, the type strain of L. fructivorans does not show such characteristics, suggesting the true hiochi-bacilli are profoundly adapted to sake environments. Although beer spoilage lactic acid bacteria do not have close taxonomic relationships with true hiochi-bacilli, there are striking similarities between these two groups of spoilage lactic acid bacteria. In this review, unique features of sake and beer spoilage lactic acid bacteria are discussed in comparative terms.

show abstract

Dynamics of pyruvate metabolism in Lactococcus lactis

Cited by 22 publications

References 14 publications

Transcriptional, translational and metabolic regulation of glycolysis in Lactococcus lactis subsp. cremoris MG 1363 grown in continuous acidic cultures

Transcriptional, translational and metabolic regulation of glycolysis in Lactococcus lactis subsp. cremoris MG 1363 grown in continuous acidic cultures

Pyruvate Formate Lyase Is Required for Pneumococcal Fermentative Metabolism and Virulence

Sake and Beer Spoilage Lactic Acid Bacteria - A Review

Contact Info

Product

Resources

About