Rotation and switching of the flagellar motor assembly in Halobacterium halobium

Marwan, Wolfgang; Alam, Maqsudul; Oesterhelt, Dieter

doi:10.1128/jb.173.6.1971-1977.1991

Cited by 81 publications

(68 citation statements)

References 34 publications

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“…Smooth swimming is performed with CCW rotating flagella only (6). In contrast, the polarly flagellated H. salinarium swims almost equally well with CW and CCW rotating flagella, but in a direction opposite to that of its cell axis (4,8). A change of swimming direction is brought about just by the change of the rotational sense.…”

Section: Vol 177 1995 Damped Oscillations In H Salinarium Phototaxmentioning

confidence: 99%

Damped oscillations in photosensory transduction of Halobacterium salinarium induced by repellent light stimuli

Krohs

1995

J Bacteriol

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Halobacteria usually respond to repellent light stimuli by reversing their swimming direction. However, cells seem to be in a refractory state when stimulated immediately after performance of a reversal. I found that in this case, a special type of response is exhibited rather than spontaneous behavior. A strong stimulus induced a rhythmic pattern of successive reversals. On stimulation immediately after a reversal of swimming direction, the first of these reversals was skipped without influence on the rhythm. The results suggest that the stimulus evokes an oscillating signal which alters reversal probability but which is itself independent of the state of the motor apparatus. The oscillation has a period length of about 5 s and is damped out within a few cycles. It does not depend on the special sensory photosystem through which the stimulus is applied. The consequences of these findings for the model description of swimming behavior control in halobacteria are discussed.Under constant conditions, Halobacterium salinarium (formerly Halobacterium halobium) reverses its swimming direction every 3 to 50 s by switching the rotational sense of its flagellar motors from clockwise (CW) to counterclockwise (CCW) or vice versa. The distribution of the interval length is highly asymmetric, with the maximum at short times of about 10 s (for a comparative compilation of different results, see reference 14; original data are presented in references 5, 7, 9, 10, and 15). Light stimuli alter the length of a swimming interval. The effect of stimulation depends on the wavelength and on the sign of the light intensity change, which is sensed by the retinal proteins sensory rhodopsins I and II (9,20,21,23,24). Stimuli which prolong a swimming interval are called attractants, and stimuli which cause a shortening of a swimming interval are called repellents. After strong repellent stimuli, all bacteria reverse their swimming direction within a few seconds. However, this response fails to occur if the stimulus is applied during the first half-second after a reversal has taken place, during the so-called refractory period. Cells regain responsiveness within the following 2 s (10, 15).It has been postulated that the swimming behavior of H. salinarium is controlled by an intracellular deterministic oscillator, which triggers a switching event after completion of each cycle. It was assumed to alter sensitivity to attractant light stimuli during the cycle (15, 16). Such an oscillator would be one of the very few examples of the occurrence of a biological clock in procaryotes, besides the circadian rhythms in certain cyanobacteria (2,11,18). But the original results in favor of the oscillator hypothesis were recently rejected as being based on inadequate methods, and constancy of the sensitivity to attractant light stimuli during a swimming interval could be demonstrated (5). There is no evidence for oscillations in the unstimulated state.In an alternative description of the system, the transition between the CW and CCW rotating states of...

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Section: Vol 177 1995 Damped Oscillations In H Salinarium Phototaxmentioning

confidence: 99%

Damped oscillations in photosensory transduction of Halobacterium salinarium induced by repellent light stimuli

Krohs

1995

J Bacteriol

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“…The filaments are composed of three flagellin species which are sulfated glycoproteins (2,13,14). Physiological evidence suggests that the individual filaments of a bundle rotate and switch synchronously (9). The mechanism of synchronization is obscure, though it might have a structural basis; however, nothing is known about the ultrastructure of the halobacterial motility apparatus, and intact flagella have not been isolated so far.…”

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The flagellar bundle of Halobacterium salinarium is inserted into a distinct polar cap structure

et al. 1994

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Flagellated envelopes of Halobacterium salinarium cells were prepared by lysis with taurodeoxycholate. After solubilization of the envelopes with Triton X-100 at high ionic strength, flagella and round patches from which numerous flagella emerged were isolated by gel filtration chromatography. We conclude that the flagellar bundle of H. salinarium is inserted into a differentiated polar cap structure.

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“…To the best of our knowledge, rotation of archaeal flagella as a mode of force generation has been reported only for Halobacterium salinarum and the so-called "square bacterium," recently described as Haloquadratum walsbyi or the SHOW (square haloarchaeum of Walsby) archaeon (1,2,10,11,33). Even for Methanococcus voltae, one of the few archaeal species which can be manipulated genetically (see reference 3 for a recent review) and which has been analyzed by K. Jarrell's group, rotation of flagella has not been proven yet (Jarrell, personal communication).…”

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confidence: 99%

Flagella ofPyrococcus furiosus: Multifunctional Organelles, Made for Swimming, Adhesion to Various Surfaces, and Cell-Cell Contacts

Näther

Rachel

Wanner³

et al. 2006

J Bacteriol

114

131

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Pyrococcus furiosus ("rushing fireball") was named for the ability of this archaeal coccus to rapidly swim at its optimal growth temperature, around 100°C. Early electron microscopic studies identified up to 50 cell surface appendages originating from one pole of the coccus, which have been called flagella. We have analyzed these putative motility organelles and found them to be composed primarily (>95%) of a glycoprotein that is homologous to flagellins from other archaea. Using various electron microscopic techniques, we found that these flagella can aggregate into cable-like structures, forming cell-cell connections between ca. 5% of all cells during stationary growth phase. P. furiosus cells could adhere via their flagella to carbon-coated gold grids used for electron microscopic analyses, to sand grains collected from the original habitat (Porto di Levante, Vulcano, Italy), and to various other surfaces. P. furiosus grew on surfaces in biofilm-like structures, forming microcolonies with cells interconnected by flagella and adhering to the solid supports. Therefore, we concluded that P. furiosus probably uses flagella for swimming but that the cell surface appendages also enable this archaeon to form cable-like cell-cell connections and to adhere to solid surfaces.The best-characterized motility organelles of prokaryotes are the flagella; these organelles have been studied a great deal for bacterial models like, e.g., Escherichia coli and Salmonella enterica serovar Typhimurium. The mechanism of flagellar motion was identified for bacteria as rotation and can be explained in molecular detail (44), as can the mechanism of elongation of this motility organelle (15,23,54). Flagellar motion as a mode of force generation was originally visualized indirectly by using dark-field light microscopy (8). Another, more direct observation method uses fluorescence dyes covalently coupled to flagella and fluorescence microscopy (48). Flagellar motion can be observed easily with this technique for E. coli, S. enterica serovar Typhimurium, and Rhizobium lupini but not for all bacteria (43,48). Our knowledge of the ultrastructure of bacterial flagella is based mainly on electron microscopy. Some bacterial flagella have been studied in great detail; in the case of S. enterica serovar Typhimurium they have been studied down to atomic resolution (55). This was achieved by step-by-step improvement of methods (34,35,36,42). Meanwhile, models for the structure of other bacterial flagella (Rhodobacter sphaeroides, R. lupini, and Caulobacter crescentus) are available at a resolution of 1 to 2 nm.In the case of archaea we have only limited data for the mode of motility and for structural components of the motility organelles themselves. To the best of our knowledge, rotation of archaeal flagella as a mode of force generation has been reported only for Halobacterium salinarum and the so-called "square bacterium," recently described as Haloquadratum walsbyi or the SHOW (square haloarchaeum of Walsby) archaeon (1, 2, 10, 11, 33). Even fo...

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Rotation and switching of the flagellar motor assembly in Halobacterium halobium

Cited by 81 publications

References 34 publications

Damped oscillations in photosensory transduction of Halobacterium salinarium induced by repellent light stimuli

Damped oscillations in photosensory transduction of Halobacterium salinarium induced by repellent light stimuli

The flagellar bundle of Halobacterium salinarium is inserted into a distinct polar cap structure

Flagella ofPyrococcus furiosus: Multifunctional Organelles, Made for Swimming, Adhesion to Various Surfaces, and Cell-Cell Contacts

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