Intracellular pH of Thermoplasma acidophila

Hsung, J.C.; Haug, A.

doi:10.1016/0005-2736(75)90158-3

Cited by 59 publications

(35 citation statements)

References 7 publications

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“…When grown at pH 2.0, Thermoplasma acidophila maintained an internal pH between 6.4 and 6.9 (9). This leads to a large proton gradient, which is compensated for by an inverted membrane potential of 120 mV (internal positive) (10).…”

Section: Discussionmentioning

confidence: 99%

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Goodwin¹,

Zeikus²

1987

J Bacteriol

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Detailed physiological studies were done to compare the influence of environmental pH and fermentation end product formation on metabolism, growth, and proton motive force in Sarcina venticuli. The kinetics of end product formation during glucose fermentation in unbuffered batch cultures shifted from hydrogen-acetate production to ethanol production as the medium pH dropped from 7.0 to 3.3. At a constant pH of 3.0, the production of acetate ceased when the accumulation of acetate in the medium reached 40 mmol/liter. At a constant pH of 7.0, acetate production continued throughout the entire growth time course. The in vivo hydrogenase activity was much higher in cells grown at pH 7.0 than at pH 3.0. The magnitude of the proton motive force increased in relation to a decrease of the meditim pH from 7.5 to 3.0. When the organism was grown at pH 3.0, the cytoplasmic pH was 4.25 and the organism was unable to exclude acetic acid or butyric acid from the cytoplasm. Addition of acetic acid, but not hydrogen or ethanol, inhibited growth and resulted in proton motive force dissipation and the accumulation of acetic acid in the cytoplasm. The results indicate that S. ventriculi is an acidophile that can continue to produce ethanol at low cytoplasmic pH values. Both the ability to shift to ethanol production and the ability to continue to ferment glucose while cytoplasmic pH values are low adapt S. ventriculi for growth at low pH.

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Section: Discussionmentioning

confidence: 99%

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Goodwin¹,

Zeikus²

1987

J Bacteriol

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“…rubrum is increased with decreasing pH of the culture medium as noted above. However, some chemotrophic bacteria are known to produce zinc complexes of porphyrins in growth media at neutral pH (Kajiwara et al, 1995;Toriya et al, 1993) and the intracellular pH of acidophilic bacteria including Acidiphilium was reported to be neutral in general (Hsung and Haug, 1975;Matin, 1999;Zychlinsky and Matin, 1983a, b). Although it is likely that acidic habitats may provide more favorable conditions for ZnBChl production by photosynthetic organisms living therein, the relationship between specific Zn-BChl requirement for photosynthesis and acidic conditions as natural habitats awaits further study.…”

Section: Concluding Remarks and Future Perspectivesmentioning

confidence: 99%

Aerobic anoxygenic photosynthetic bacteria with zinc-bacteriochlorophyll.

Hiraishi

Shimada

2001

J. Gen. Appl. Microbiol.

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IntroductionChlorophylls (Chls) and bacteriochlorophylls (BChls) are porphyrin derivatives chelated with magnesium, and represent a class of lipophilic pigments involved in natural photosynthesis. There has been no rational explanation for why extant phototrophic organisms have used Mg exclusively as the central metal with which the chlorophyllous pigments are complexed. Apart from this question, phototrophic organisms that use Chls or BChls containing metals other than Mg were unknown for a long time. Recently, this common understanding of natural photosynthesis was unexpectedly modified by the new finding that a novel purple pigment, zinc-chelated-BChl (Zn-BChl) (for abbreviations, see Takaichi et al. (1999)), was discovered in a specific group of obligately aerobic bacteria (Hiraishi et al., 1998;Wakao et al., 1996Wakao et al., , 1999.It has been satisfactorily demonstrated that BChls are present not only in facultatively and obligately anaerobic anoxygenic phototrophic bacteria but also in large numbers of species of obligately aerobic bacteria Naturally occurring chlorophyllous pigments, which function as the cofactor in the early photochemical reaction of photosynthesis, have been proven beyond question to be magnesium-complexed porphyrin derivatives. Phototrophic organisms that use (bacterio)chlorophylls ([B]Chls)containing metals other than Mg were unknown for a long time. This common knowledge of natural photosynthesis has recently been modified by the striking finding that a novel purple pigment, zinc-chelated-BChl (Zn-BChl) a, is present as the major and functional pigment in species of the genus Acidiphilium. Acidiphilium species are obligately acidophilic chemoorganotrophic bacteria that grow and produce photopigments only under aerobic conditions. Although the mechanism of photosynthesis with Zn-BChl a in Acidiphilium species is similar to that seen in common purple bacteria, some characteristic photosynthetic features of the acidophilic bacteria are also found. The discovery of natural photosynthesis with Zn-BChl has not only provided a new insight into our understanding of bacterial photosynthesis but also raised some interesting questions to be clarified. The major questions are why the acidophilic bacteria have selected ZnBChl for their photosynthesis and how they synthesize Zn-BChl and express photosynthetic activity with it in their natural habitats. In this article we review the current knowledge of the biology of Acidiphilium as aerobic photosynthetic bacteria with Zn-BChl a and discuss the interesting topics noted above.

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“…For example, for the closely related archaeon Thermoplasma acidophilum, also growing at pH 2, an internal pH of 6.6 has been measured (39). The fact that the aa 3 oxidase is the only oxidase expressed when the archaeon is grown under aerobic conditions indicates that this enzyme participates in cell respiration.…”

mentioning

confidence: 99%

Redox-linked transient deprotonation at the binuclear site in the aa ₃ -type quinol oxidase from Acidianus ambivalens : Implications for proton translocation

Das

Gomes

Teixeira

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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The hyperthermophilic archaeon Acidianus ambivalens expresses a membrane-bound aa 3 -type quinol oxidase, when grown aerobically, that we have studied by resonance Raman spectroscopy. The purified aa 3 oxidase, which does not contain bound quinol, undergoes a reversible slow conformational change at heme a 3 upon reduction, as indicated by a change in the frequency of its heme formyl stretching mode, from 1,660 cm ؊1 to 1,667 cm ؊1 . In contrast, upon reduction of the integral membrane enzyme or the purified enzyme preincubated with decylubiquinol, this mode appears at 1,667 cm ؊1 much more rapidly, suggesting a role of the bound quinol in controlling the redox-linked conformational changes. The shift of the formyl mode to higher frequency is attributed to a loss of hydrogen bonding that is associated with a group having a pKa of Ϸ3.8. Based on these observations, a crucial element for proton translocation involving a redox-linked conformational change near the heme a 3 formyl group is postulated.

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Intracellular pH of Thermoplasma acidophila

Cited by 59 publications

References 7 publications

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Aerobic anoxygenic photosynthetic bacteria with zinc-bacteriochlorophyll.

Redox-linked transient deprotonation at the binuclear site in the aa ₃ -type quinol oxidase from Acidianus ambivalens : Implications for proton translocation

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Intracellular pH of Thermoplasma acidophila

Cited by 59 publications

References 7 publications

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Aerobic anoxygenic photosynthetic bacteria with zinc-bacteriochlorophyll.

Redox-linked transient deprotonation at the binuclear site in the aa 3 -type quinol oxidase from Acidianus ambivalens : Implications for proton translocation

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Redox-linked transient deprotonation at the binuclear site in the aa ₃ -type quinol oxidase from Acidianus ambivalens : Implications for proton translocation