Velocity changes, long runs, and reversals in the Chromatium minus swimming response

Mitchell, James G.; Martínez-Alonso, Maira; Lalucat, J; Esteve, Isabel; Brown, Simon

doi:10.1128/jb.173.3.997-1003.1991

Cited by 32 publications

(33 citation statements)

References 22 publications

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“…Thereafter, cells reoriented randomly, and resumed forward swimming. We observed a different motile behavior for M. gracile, a finding consistent with the observation made for Allochromatium vinosum by Mitchell et al (29).…”

Section: Discussionsupporting

confidence: 81%

“…The motile behavior of M. gracile can generally be described as a random walk (2,29). Intervals of straight swimming paths are interrupted by stops, followed by a reversal in swimming direction.…”

Section: Discussionmentioning

confidence: 99%

“…Chromatium cells accumulate around air bubbles in the absence of light but move away if illuminated (1) (an observation that has been erroneously cited to be already observed by Engelmann [9] in 1883). Beside the photophobic response, Chromatium exhibits also photokinesis (29), i.e., swimming velocities are correlated to the illumination intensity.…”

mentioning

confidence: 99%

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Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

Thar

Kühl

2001

Appl Environ Microbiol

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

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Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

Thar

Kühl

2001

Appl Environ Microbiol

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“…In the only other comparable study on the effect of viscosity on locomotory velocity at low Re, Mitchell et al (1991) reported that water viscosity accounted for only 26% of the decline in swimming velocity of the purple sulphur bacterium Chromatium minus over a 30°C temperature drop (from 45 to 15OC). The increase in viscosity over this temperature range is far greater than that in either this study or that of Podolsky & Emlet (1993), and raises the question of why viscosity seems to play such a relatively minor role in locomotory kinetics of C. minus (26 %) compared to the larvae of Dendraoter excentricus (40%) and Galeolaria caespitosa (46%).…”

Section: Swimming Velocitymentioning

confidence: 96%

Physiological versus viscosity-induced effects of water temperature on the swimming and sinking velocity of larvae of the serpulid polychaete Galeolaria caespitosa

Bolton¹,

Havenhand²

1997

Mar. Ecol. Prog. Ser.

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Water viscosity is inversely related to water temperature. Because marine invertebrate larvae generally operate in a hydrodynamic environment dominated by viscous forces (i.e. Reynolds numbers < l ) , temperature-induced changes in water viscosity may exert profound influence on the swimming and sinking velocity of larvae. Wh~lst the physiological effects of water temperature on larval locomotion have received considerable experimental investigation, the influence of temperatureinduced changes in water viscosity has received little attention. We investigated the relative physiological and viscosity-induced effects of water temperature at 25 and 15°C on the swimming and sinking velocity of larvae of the serpulid polychaete Galeolaria caespitosa (L.). Larvae of this species undergo considerable growth and development during their planktonic period such that the Reynolds number of the larval body (trochosphere) increases from 0.19 at hatching to 1.11 at 120 h post-hatching. Consequently we suggest that inertial forces may exert an influence on swimming at the later stages of larval development and therefore the influence of viscosity may change over the course of larval development. We also suggest that a temperature-induced increase in water viscosity will reduce the sinking velocity of larvae and may reduce the energy expenditure required to maintain location in the water column. Our results indicate that both physiological and viscosity components of water temperature influence the swimming velocity of G. caespitosa larvae. However, the influence of water viscosity did not change significantly over the course of larval development. The sinking velocity of G. caespitosa larvae was reduced with a temperature-induced increase in water viscosity. The reduction in sinking velocity of the larvae was proportional to the increase in water viscosity. We estimated and compared the metabolic costs of swimming to counteract sinking at 25 and 15°C by estimating Qlo values from the metabolic effects of temperature on swimming velocity. We suggest that the metabolic costs of stvimming to counteract sinking in G. caespitosa larvae are similar at 25 and 15"C, but that the metabolic costs of swimming are slightly higher at 15°C.

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“…The video image was recorded continuously by a video camera (FCD-725; Ikegami Co.) and a video cassette recorder (BR9000; Hitachi Co.). Run times were measured as previously described (14). Measurements were made on the monitor screen by stretching plastic wrap flat against the screen surface and following a cell with a permanent marking pen.…”

Section: Methodsmentioning

confidence: 99%

Isolation and characterization of chemotaxis mutants and genes of Pseudomonas aeruginosa

et al. 1995

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Two chemotaxis-defective mutants of Pseudomonas aeruginosa, designated PC1 and PC2, were selected by the swarm plate method after N-methyl-N-nitro-N-nitrosoguanidine mutagenesis. These mutants were fully motile but incapable of swarming, suggesting that they had a defect in the intracellular signalling pathway. Computerassisted capillary assays confirmed that they failed to show behavioral responses to chemical stimuli, including peptone, methyl thiocyanate, and phosphate. Two chemotaxis genes were cloned by phenotypic complementation of PC1 and PC2. From nucleotide sequence analysis, one gene was found to encode a putative polypeptide that was homologous to the enteric CheZ protein, while the other gene was cheY, which had been previously reported (M. N. Starnbach and S. Lory, Mol. Microbiol. 6:459-469, 1992). Deletion and complementation analysis showed that PC1 was a cheY mutant, whereas PC2 had a double mutation in the cheY and cheZ genes. A chromosomal cheZ mutant, constructed by inserting a kanamycin resistance gene cassette into the wild-type gene, changed its swimming direction much more frequently than did wild-type strain PAO1. In contrast, cheY mutants were found to rarely reverse their swimming directions.Chemotaxis is the movement of an organism toward chemical attractants and away from chemical repellents (1). Pseudomonas aeruginosa is attracted to various amino acids (6) and is less strongly responsive to sugars and organic acids (15, 16). The taxis toward several amino acids is subject to control by nitrogen availability in a manner similar to the control of various enzymes of nitrogen metabolism (6) and is mediated by methylation and demethylation of methyl-accepting proteins analogous to those of the enteric bacteria (5). The strengths of the chemotactic responses to glucose and to citrate are also dependent on prior growth of the bacterial cells on those carbon sources (16). The glucose-binding protein has been identified as the glucose chemoreceptor in this organism (28). However, virtually nothing is known about the other chemoreceptors of P. aeruginosa. Our previous work demonstrated that P. aeruginosa is attracted to P i (10). This chemotactic response is induced by P i limitation. The P i -starved cells are also attracted to arsenate (11). Since P i competitively inhibits the response to arsenate, both P i and arsenate are likely to be detected by the same chemoreceptor. Genetic evidence showed that P i taxis in P. aeruginosa is not regulated by the phoB and phoR gene products but requires the phoU gene (12). P. aeruginosa is also repelled by thiocyanic and isothiocyanic esters, including allyl isothiocyanate, ethyl thiocyanate, methyl isothiocyanate, and methyl thiocyanate (19).The molecular mechanisms that underlie bacterial chemotaxis have been studied intensively with the enteric bacteria Escherichia coli (20) and Salmonella typhimurium (30) and to a lesser extent with the gram-positive bacterium Bacillus subtilis (4). However, little is known about the chemotaxis genes in the bacteri...

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Velocity changes, long runs, and reversals in the Chromatium minus swimming response

Cited by 32 publications

References 22 publications

Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

Physiological versus viscosity-induced effects of water temperature on the swimming and sinking velocity of larvae of the serpulid polychaete Galeolaria caespitosa

Isolation and characterization of chemotaxis mutants and genes of Pseudomonas aeruginosa

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