The Interrelation Of Phototaxis, Membrane Potential And K+/Na+ Gradient In Halobacterium Halobium

Baryshev, V.A.; Glagolev, A.N.; Skulachev, Vladimir P.

doi:10.1099/00221287-129-2-367

Cited by 11 publications

(18 citation statements)

References 19 publications

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“…The previous results obtained in our group have shown that DCCD and cyanide, the inhibitors of light-independent A/2H generators in H. halobium strongly increased the sensitivity of the cells to the attractant effect of the long wavelength light [8,9]. This fact was interpreted as indicating a A/2H-dependent mechanism of reception in the green light response.…”

Section: Resultsmentioning

confidence: 75%

“…40% decrease in the light intensity by a neutral filter was used as a stimulus. Additions: 0.1 mM DCCD and 1 mM NaCN bacteria in a A/~H-dependent manner [9]. The studies on various species of bacteria demonstrated that aerotaxis and A/~H reception were controlled by similar, if not identical, mechanisms [14,15].…”

Section: Resultsmentioning

confidence: 98%

“…Cells were harvested, as in [9], in a peptone medium and were resuspended before experiments in a basal salt solution containing 4.3 M NaCI, 27 mM KC1, 81 mM MgSO4 and 25 mM Mops, pH 7.0.…”

Section: Methodsmentioning

confidence: 99%

“…It was suggested earlier in our group that operation of bacteriorhodopsin as the light-driven H + pump results in a AfiH increase which is sensed by a special AfiH receptor ('protometer') [8,9]. The same A/z-I-I receptor may be involved in the halorhodopsin-mediated attractant effect of the light since the halorhodopsin- This paper is dedicated to the 60th birthday of Professor W. Nultsch produced A¢ must, according to definition, be monitored by the protometer.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of phototaxis and aerotaxis in Halobacterium halobium

Bibikov

Skulachev

1989

FEBS Letters

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DCCD and cyanide, the H +-ATPase and respiratory chain inhibitors, increase the sensitivity of Halobacterium halobium to the attractant effect of light. This phenomenon requires the presence of bacteriorhodopsin and occurs at high light intensities (about 100 W/m2). Strains lacking both bacteriorhodopsin and halorhodopsin exhibit an increased sensitivity of aerotaxis. These observations are in good agreement with the hypothesis that A/)H reception is one of the mechanisms responsible for phototaxis and aerotaxis in H. halobium.

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Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 98%

“…Cells were harvested, as in [9], in a peptone medium and were resuspended before experiments in a basal salt solution containing 4.3 M NaCI, 27 mM KC1, 81 mM MgSO4 and 25 mM Mops, pH 7.0.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanisms of phototaxis and aerotaxis in Halobacterium halobium

Bibikov

Skulachev

1989

FEBS Letters

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“…This function is related to the proton-translocating activity of bacteriorhodopsin (7-10), and it has been suggested that receptor function is mediated by a device that monitors electrochemical gradient of hydrogen ions across the membrane (⌬ H ϩ) called a protometer (5,6,10,15,35). This supports other data on the photoreceptory function of bacteriorhodopsin which also attributed the effects of bacteriorhodopsin on swimming behavior to a secondary consequence of electrogenic proton pumping on metabolic or signal-transducing pathways rather than to primary sensory signaling such as that mediated by sRI (46).…”

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confidence: 99%

delta psi-mediated signalling in the bacteriorhodopsin-dependent photoresponse

et al. 1996

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It has been shown previously that the proton-pumping activity of bacteriorhodopsin from Halobacterium salinarium can transmit an attractant signal to the bacterial flagella upon an increase in light intensity over a wide range of wavelengths. Here, we studied the effect of blue light on phototactic responses by the mutant strain Pho81-B4, which lacks both sensory rhodopsins but has the ability to synthesize bacteriorhodopsin. Under conditions in which bacteriorhodopsin was largely accumulated as the M 412 bacteriorhodopsin photocycle intermediate, halobacterial cells responded to blue light as a repellent. This response was pronounced when the membrane electric potential level was high in the presence of arginine, active oxygen consumption, or high-background long-wavelength light intensity but was inhibited by an uncoupler of oxidative phosphorylation (carbonyl cyanide 3-chlorophenylhydrazone) and was inverted in a background of low long-wavelength light intensity. The response to changes in the intensity of blue light under high background light was asymmetric, since removal of blue light did not produce an expected suppression of reversals. Addition of ammonium acetate, which is known to reduce the pH gradient changes across the membrane, did not inhibit the repellent effect of blue light, while the discharge of the membrane electric potential by tetraphenylphosphonium ions inhibited this sensory reaction. We conclude that the primary signal from bacteriorhodopsin to the sensory pathway involves changes in membrane potential.Halobacterium salinarium cells swim by means of bipolar flagellar tufts. Smooth swimming is occasionally interrupted by spontaneous cell reversals which are produced by changes in the direction of flagellar rotation. The frequency of spontaneous reversals varies depending on the culture conditions and the particular strain (2,31,38,40,41).An important behavior of halobacteria is phototaxis, which these bacteria use to find the optimal light conditions for photosynthesis and to avoid the harmful effect of UV light. Changes in light intensity are sensed by retinal-containing proteins which control the direction of flagellar rotation through a system of sensory proteins. Increases in UV or blue light intensity or decreases in red or orange light are interpreted by the cells as unfavorable changes of environmental conditions and cause reversal of swimming direction. Decreases in UVblue or increases in red-orange light suppress reversals. Two specialized photosensory systems have been identified in halobacteria. Sensory rhodopsins I and II (sRI [11,38,39] and sRII [24,37,[42][43][44][45], respectively) serve as receptors for light with maximal absorbance at 578 and 487 nm, respectively. Photoexcitation of sRI generates a long-lived sensory rhodopsin intermediate, S 373 , which triggers an attractant response by the cell (11). At the same time, S 373 operates as a third specialized photoreceptor. While attractant light is detected by the ground form of the sRI molecule, repellent light is detec...

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The Halobacteriaceae

Kushner¹

1985

Archabacteria

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The Interrelation Of Phototaxis, Membrane Potential And K+/Na+ Gradient In Halobacterium Halobium

Cited by 11 publications

References 19 publications

Mechanisms of phototaxis and aerotaxis in Halobacterium halobium

Mechanisms of phototaxis and aerotaxis in Halobacterium halobium

delta psi-mediated signalling in the bacteriorhodopsin-dependent photoresponse

The Halobacteriaceae

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