pH homesstasis in bacteria

Padan, Etana; Zilberstein, Dan; Schuldiner, Shimon

doi:10.1016/0304-4157(81)90004-6

Cited by 414 publications

(273 citation statements)

References 84 publications

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“…The cytoplasmic concentration of Ca# + in plant cells has been related to changes in intracellular pH (Felle, 1988 ;Bush, 1995), although it is not known how protons and Ca# + interact. There is also evidence of a similar relationship in bacteria (Padan et al, 1981 ;O'Hara et al, 1989 ;Tiwari et al, 1992).…”

Section: mentioning

confidence: 89%

Role of external calcium in homeostasis of intracellular pH in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

1999

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The role of external Ca2+ in the homeostasis of intracellular pH (pHi) of Anabaena sp. strain PCC7120 in response to a decrease in the external pH (pHex) has been studied in cell suspensions. Increase in cytoplasmic pH after acid shock is dependent on the presence of Ca2+ in the medium. The observed Ca2+‐mediated alkalization of the cytoplasm depends on the extent of the shift in external pH. Acid pH shifts resulted in an increased permeability of the cytoplasmic membrane to protons, which could be reversed by increasing the concentration of Ca2+ in the medium. Thus, the ability of Ca2+ to increase cytoplasmic pH might be correlated with an inhibition of net proton uptake by increasing concentrations of external Ca2+ under these conditions. This combined response resulted in the generation and maintenance of a larger pH gradient (ΔpH) at acid external pH values. All Ca2+ channel blockers tested, such as verapamil and LaCl3, inhibited the observed Ca2+‐mediated response. On the other hand, the Ca ionophore calcimycin (compound A23187) was agonistic, and stimulated both cytoplasmic alkalization and inhibition of net proton uptake. The protonophorous uncoupler carbonylcyanide m‐chlorophenyl hydrazone, inhibited this Ca2+‐mediated response, whereas monensin, an inhibitor of the Na+/H+ antiporter, had no significant effect. The results of the present study suggest that an influx of Ca2+ from the extracellular space is required for the regulation of cytoplasmic pH in Anabaena sp. strain PCC7120 exposed to low external pH values.

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Section: mentioning

confidence: 89%

Role of external calcium in homeostasis of intracellular pH in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

1999

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“…bulgaricus does not maintain a pH, close to neutrality when pH,, decreases (Kashket, 1987) (Kashket, 1987;Russell, 1992;Hutkins & Nannen, 1993 (Cook & Russell, 1994) demonstrate that pH, decreases as a function of pH,, in the presence of glucose. As bacteria maintaining a constant ApH rather than a constant pH, are not pH-homeostatic in the classical sense (Padan et al, 1981), these bacteria might be recognized as a distinct class.…”

Section: Calibration Curve For Measuring Phi In Single Cellsmentioning

confidence: 99%

Use of fluorescence ratio imaging for intracellular pH determination of individual bacterial cells in mixed cultures

Siegumfeldt¹,

Rechinger²,

Jakobsen³

1999

Microbiology

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The development of a rapid method for measuring intracellular pH (pH,) in single bacterial cells is described. Lactobacillus delbrueckii subsp. bulgaricus and Listeria innocua were used as test organisms. The method is based upon fluorescence microscopy and ratio imaging of cells stained with carboxyfluorescein succinimidyl ester. After staining, the bacteria were immobilized on a membrane filter and transferred to a closed perfusion chamber, allowing control of the cell environment during analysis. The set-up was optimized with regard to the use of neutral-density filters and background subtraction, for determining the excitation ratio 490 nm/435 nm (R49,,,435) independent of the excitation light intensity, and to reduce photobleaching. This allowed for time-lapse studies with multiple exposures.To study the pH, of Lb. delbrueckii subsp. bulgaricus and L. innocua in response to different extracellular pH (pH,,) values, an in vivo calibration curve was constructed in the pH, range 5-0-8-5. Distinct differences between the two cultures were observed. L. innocua maintained a near-neutral pH, almost independently of pH, (5-&8-0), whereas the pH, of Lb. delbmeckii subsp.bulgaricus decreased with decreasing pH, ,. In pure and mixed cultures a t pH, 5-0, the pH, values of Lb. delbmeckii subsp. bulgaricus and L. innocua were 6120.2 and 7.5202, respectively. This difference in pH, may explain how Lb. delbrueckii subsp. bulgaricus obtains a competitive advantage over L. innocua at low pH, , .Keywords : intracellular pH, ratio imaging, single cells, Lactobacillus delbrueckii subsp. bulgaricus, Listeria innocua INTRODUCTIONMost bacteria maintain an intracellular pH (pH,) close to neutral within fairly narrow limits (Padan et al., 19Sl), because this enables metabolic reactions to occur even under unfavoura ble extracellular pH (pH,,) conditions. Bacteria can be divided into three groups with regard to pH homeostasis : neutrophiles, acidophiles and alkalophiles. These groups differ in requirement for pH,,, but all groups maintain a pH, between 6.5 and 9-5 (White, 1995). Acidophiles maintain a large gradient between pH, and pH,, (ApH), but are restricted to growth in very acidic environments due to an inverted membrane potential (White, 1995 group of acid-tolerant fermentative bacteria grows at pH values ranging from neutral to pH 3-5 (Kashket, 1987;McDonald et al., 1990; Russell, 1991a). This group consists of certain ruminal bacteria (Russell, 1991b) and various species of lactic acid bacteria (Kashket, 1987). A common feature is the ability to decrease their pH, with pH,, during growth (Russell & Hino, 1985;Nannen & Hutkins, 1991a;Cook & Russell, 1994), and therefore this group of bacteria does not comply with the conventional classification of pH homeostasis. The pronounced organic acid production of these bacteria creates an environment unfavourable for most other organisms (Russell, 1992), which is the basis of many methods of food preservation by fermentation.Food fermentations are often carried out by a concerte...

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“…However, one way to determine the essential features of the homeostatic system is to assess the ability of bacterial cells to cope with changes in external pH (pHex) in the presence and absence of various ions, principally sodium and potassium. The Na'^/H'*' and K^/H"*" antiporters, and H"^ pumps have been proposed as being part of this homeostatic system (Padan et al, 1981;Nakamura, Tokuda & Unemoto, 1984;Booth, 1985;Krulwich, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…The cytoplasmic concentration of Ca in plant cells has been related to changes in intracellular pH and vice versa (Felle, 1988;Bush, 1995), although it is not known how protons and Ca interact. There is also some evidence from bacteria to support such a relationship (Padan et al, 1981). Calcium ions play a variety of important roles in eukaryotic cells, but Ca has attracted most attention in prokaryotes, owing to its possible involvement in mechanisms regulating responses to environmental variables (Smith, 1995;Norris et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

The relationship between intracellular pH, growth characteristics and calcium in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

et al. 1997

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SUMMARYChanges in various cell functions were examined during a shift of the cyanobacterium Anabaena sp. strain PCC7120 to acidic external pH (pHex) in the presence and absence of added calcium. In the presence of 0-25 mM Ca (the standard Ca concentration of the growth medium), growth and O^ evolution were inhibited at pH values lower than 6. The cyanobacterium was unable to maintain a relatively constant internal pH (pHi) at pH 6 and below, which led to acidification of the cytoplasm. In the absence of Ca, the acidification found at acid pH values was even more pronounced. The elimination of Ca did not affect pHi at pHex of 6-5 and above. Increased acidification of the internal cell contents correlated well wdth a general impairment of growth in Ca-deficient cells exposed to external acid pH values. On the other hand, Ca enrichment of cells grown under acidic conditions resulted in a significant improvement of several physiological processes. The protein pattern of cell extracts of Anabaena sp. strain PCC7120 was altered by acidity. The most significant modifications of the protein profiles induced at low^ pH were not evident in the presence of high concentrations of Ca. Increasing concentrations of Ca allowed Anabaena sp. strain PCC7120 to perform better at lower pH.

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pH homesstasis in bacteria

Cited by 414 publications

References 84 publications

Role of external calcium in homeostasis of intracellular pH in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

Role of external calcium in homeostasis of intracellular pH in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

Use of fluorescence ratio imaging for intracellular pH determination of individual bacterial cells in mixed cultures

The relationship between intracellular pH, growth characteristics and calcium in the cyanobacterium Anabaena sp. strain PCC7120 exposed to low pH

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