Glutamine and proline accumulation by Staphylococcus aureus with reduction in water activity

Anderson, Carl B.; Witter, Lloyd D.

doi:10.1128/aem.43.6.1501-1503.1982

Cited by 63 publications

(32 citation statements)

References 9 publications

(3 reference statements)

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“…In Gram-negative bacteria these compounds include amino acids, such as proline [92][93][94][95], as well as glutamate, which is often the counterion for accumulated K + [84]. Staphylococci accumulate glutamine and proline when osmotically stressed [96]. Of the common compatible solutes glycine betaine (betaine) seems to be the best.…”

Section: Osmotolerancementioning

confidence: 99%

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Kashket¹

1987

FEMS Microbiology Letters

349

209

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Lactic acid bacteria maintain a cytoplasm that is more alkaline than the medium, but whose pH decreases as the medium is acidified during growth and fermentation. Streptococci generally acidify the cytoplasm from approximately pH 7.6 to 5.7 (external pH 4.5) before growth and then fermentation cease. The internal enzyme machinery of these anaerobic fermenters thus tolerates a fairly wide range in internal proton concentration. Lactobacilli tolerate a significantly more acidic cytoplasmic pH of 4.4 (external pH 3.5). However, when the cytoplasmic pH decreases below a threshold pH, which depends on the organism cellular functions are inhibited. Fermentation end‐products, such as organic acids or alcohols, exert their deleterious effects by bringing about acidification of the cytoplasm below the permissible pH. Organic acids, which act as protonophores, or solvents, which perturb membrane phospholipids, at high concentrations increase the inward leak of H+ so that H+ efflux is not rapid enough to alkalinize the cytoplasm. The membrane pH gradient is thus dissipated. A specific strain of Lactobacillus acidophilus has been found to be unusually osmotolerant. The osmoresistance is due to the cells' capacity to accumulate glycine betaine by a transport carrier that is activated, but not induced, by high medium osmotic pressure.

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Section: Osmotolerancementioning

confidence: 99%

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Kashket¹

1987

FEMS Microbiology Letters

349

209

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“…This process is often referred to as osmoregulation. The biochemical basis of osmoregulation has been the subject of several reports in the past decade (Anderson and Witter, 1982;Csonka, 1989; Larsen et al, 1987;Gervais et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Water Activity, Glass Transition and Microbial Stability in Concentrated/Semimoist Food Systems

Chirife

Buera

1994

Journal of Food Science

110

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This review examines recent published suggestions that “water dynamics” may be applied instead of water activity (aw) determination to predict microbial stability of concentrated and intermediate moisture food systems. Factors such as the relative effectiveness of additives for antimicrobial stabilization through aw‐lowering (i.e. glucose vs fructose, glycerol vs propylene glycol) and the importance of glass transition temperature as an indicator of microbial stability were examined, based on available experimental data. Determination of the glass‐rubber transition characteristics and/or the use of the “water‐dynamics” map does not enable prediction of the microbial stability of foods (i.e. inhibition of growth) with confidence. These were no more effective alternatives than the concept of water activity as a basis for predicting microbial growth in foods.

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“…3). Glutamine as well as proline accumulate under NaCl stress conditions in S. aureus, indicating that glutamine also plays an important role in osmotic regulation (Anderson & Witter, 1982). However, under the osmotic stress conditions tested in this previous study, glutamine accumulation was proposed to be due to synthesis rather than uptake (Anderson & Witter, 1982).…”

Section: Discussionmentioning

confidence: 99%

“…Glutamine as well as proline accumulate under NaCl stress conditions in S. aureus, indicating that glutamine also plays an important role in osmotic regulation (Anderson & Witter, 1982). However, under the osmotic stress conditions tested in this previous study, glutamine accumulation was proposed to be due to synthesis rather than uptake (Anderson & Witter, 1982). In terms of other functions of the glutamine transporter AlsT in S. aureus; it is interesting to note that in a recent study investigating genetic determinants required for eDNA during biofilm formation, it was found that inactivation of GdpP as well as AlsT results in a significant decrease in eDNA release (DeFrancesco et al ., 2017).…”

Section: Discussionmentioning

confidence: 99%

Identification of the main glutamine and glutamate transporters inStaphylococcus aureusand their impact on c-di-AMP production

Zeden

Kviatkovski

Schuster

et al. 2019

Preprint

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words) 24The nucleotide second messenger c-di-AMP negatively regulates potassium and osmolyte 25 uptake in Staphylococcus aureus and many other bacteria. c-di-AMP is also important for 26 growth and an S. aureus strain deleted for the c-di-AMP cyclase gene dacA is unable to 27 survive in rich medium unless it acquires compensatory mutations. Previously, we have 28 shown that an S. aureus dacA mutant can grow after the acquisition of inactivating mutants 29 in opuD, encoding the main glycine-betaine osmolyte transporter, or mutations in alsT, 30 encoding a predicted amino acid transporter. Using the size of bacterial cells as a proxy for 31 their osmotic balance, we show that inactivation of OpuD helps bacteria to re-establish their 32 osmotic balance, while inactivation of AlsT does not and bacteria remain enlarged, a 33 characteristic of S. aureus cells unable to produce c-di-AMP. We show that AlsT is the main 34 glutamine transporter in S. aureus, thus revealing that S. aureus can survive without c-di- 35AMP when glutamine uptake is prevented. Using a bioinformatics approach combined with 36 uptake assays, we identified GltS as the main glutamate transporter in S. aureus. Using WT 37 and mutant strain, we show that glutamine is preferred over glutamate for bacterial growth 38 and that its uptake represses c-di-AMP production. Glutamine and glutamate are important 39 players in osmotic regulation, but their cellular levels also serve as a key indicator of 40 nitrogen availability in bacterial cells. Therefore, we not only provide a further connection 41 between the c-di-AMP signalling network and osmotic regulation in S. aureus but also to 42 central nitrogen metabolism.

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Glutamine and proline accumulation by Staphylococcus aureus with reduction in water activity

Abstract: Staphylococcus aureus MF-31 challenged by 5.8 or 10% NaCl in the growth medium. The accumulation of glutamine was the result of its synthesis, whereas the accumulation of proline was by transport. Most bacteria, except for the halophiles, grow optimally at high water activity (a,). These

Cited by 63 publications

References 9 publications

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Bioenergetics of lactic acid bacteria: cytoplasmic pH and osmotolerance

Water Activity, Glass Transition and Microbial Stability in Concentrated/Semimoist Food Systems

Identification of the main glutamine and glutamate transporters inStaphylococcus aureusand their impact on c-di-AMP production

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