Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Kashket, Eva R.

doi:10.1111/j.1574-6968.1987.tb02463.x

Cited by 349 publications

(227 citation statements)

References 102 publications

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“…This implied that the part of energy dedicated to maintenance by L. lactis was increased at low pH, as described previously for lactic acid bacteria (Kashket, 1987). A fraction of this energy is probably rerouted towards ATPase activity in order to increase the DpH under acidic conditions.…”

Section: Discussion Acid Stress Damagesmentioning

confidence: 71%

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

2003

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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.

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Section: Discussion Acid Stress Damagesmentioning

confidence: 71%

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

2003

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“…Both the external and the internal pH decreased concomitantly during the culture (Tab. II), as previously known [11], but to different extents, leading to an increase in the ∆pH. This increase enables the internal pH to be maintained at values compatible with growth and survival [7,18].…”

Section: Discussionmentioning

confidence: 68%

Article

Mercade

Duperray

Loubière

2003

Lait

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-Growth and energetic parameters of Lactobacillus delbrueckii subsp. bulgaricus were measured during cultures in synthetic medium, at pH regulated at 6.4 and at free pH. These data enabled the actual biomass yield relative to ATP and the maintenance coefficient to be calculated, and the type of control between catabolism and anabolism to be identified. The cultures of L. delbrueckii subsp. bulgaricus at pH 6.4 or at a non-regulated pH were characterized by a concomitant and early decrease in both catabolism and anabolism. At a regulated pH, the growth decrease seems to be due to the accumulation of toxic compounds, acting on anabolic reactions. This inhibition led to a decrease in the catabolic flux, albeit to a lower extent than the anabolic flux. In this condition, the culture was characterized by an excess of energy. On the contrary, at free pH, the lactic acid production led to a pH decrease responsible for the slowing-down of the catabolic flux. At the same time, maintaining the internal pH in the acidified medium was more energy-consuming. The consequence of both the decrease in the glycolytic flux and the increase in the energy consumption led to an energy limitation of growth, as shown by the lower value of the maintenance coefficient.Lactic acid bacteria / Lactobacillus delbrueckii subsp. bulgaricus / energetic analysis / catabolism / anabolism / maintenance coefficient Résumé -Les apports de l'énergétique microbienne à l'analyse des cultures de Lactobacillus delbrueckii subsp. bulgaricus : identification du type de contrôle entre catabolisme et anabolisme. La croissance et les paramètres énergétiques de Lactobacillus delbrueckii subsp. bulgaricus sont quantifiés en cinétique de culture en milieu synthétique, à pH régulé à 6,4 et à pH libre. Ces données permettent d'estimer le rendement ponctuel de biomasse par rapport à l'ATP et le coefficient de maintenance, paramètres dont l'analyse permet d'identifier le type de contrôle reliant le catabolisme à l'anabolisme. Lors des cultures de L. delbrueckii subsp. bulgaricus à pH régulé à 6,4 comme à pH libre, un ralentissement concomitant du catabolisme et de l'anabolisme est observé très précocement en cours de culture. À pH régulé, le ralentissement de croissance semble dû à l'accumulation de produits toxiques, qui affecte en premier lieu l'anabolisme, l'inhibition de l'anabolisme provoquant un rétro-contrôle du flux catabolique, mais dans des proportions moindres que l'anabolisme. La culture est alors en situation d'excédent énergétique. Inversement, à pH libre, la production d'acide lactique provoque une diminution du pH responsable d'un ralentissement du catabolisme. En même temps, l'acidification engendre un coût énergétique supplémentaire pour le * Corresponding author: loubiere@insa-tlse.fr 40 M. Mercade et al.

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“…plantarum maintains a ApH with malic acid at low pH. The generation of ApH is via the membrane-bound H+-ATPase in most LAB (Kobayashi et al, 1982;Kashket, 1987). When cells were treated with DCCD at pH 5.5, to inhibit H+-ATPase, the ApH in the presence of either glucose or malic acid was dissipated as expected.…”

Section: Discussionmentioning

confidence: 93%

Energy production from L-malic acid degradation and protection against acidic external pH in Lactobacillus plantarum CECT 220

García

Zúñiga

Kobayashi

1992

Journal of General Microbiology

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Malate degradation by Luctobaciffus pfanturum CECT 220 provides energy which enables this organism to remain viable for longer at low environmental pH values. Energy production was not coupled to H+-ATPase activity. This protective mechanism against acidic external pH is complemented by another system of ApH maintenance. The H+-ATPase did not seem to be involved in this system of pH maintenance as the system was not sensitive to N , Ndicyclohexylcarbodiimide (DCCD) and was functional at very low pH values where ATPase activity was severely inhibited.

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Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Cited by 349 publications

References 102 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

Article

Energy production from L-malic acid degradation and protection against acidic external pH in Lactobacillus plantarum CECT 220

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