Bidirectional phototaxis by Dictyostelium discoideum slugs

Fisher, Paul R.

doi:10.1016/0378-1097(81)90043-4

Cited by 12 publications

(18 citation statements)

References 8 publications

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“…Another observation that can be clari¢ed by our model is that when slugs are formed at high cell density, bidirectional phototaxis becomes more extreme (Fisher & Williams 1981). At high cell density NH 3 concentrations will become higher, and as a result the bidirectionality will be stronger.…”

Section: Discussionmentioning

confidence: 78%

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Phototaxis during the slug stage of Dictyostelium discoideum: a model study

Marée

Panfilov

Hogeweg

1999

Proc. R. Soc. Lond. B

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During the slug stage, the cellular slime mould Dictyostelium discoideum moves towards light sources. We have modelled this phototactic behaviour using a hybrid cellular automata/partial di¡erential equation model. In our model, individual amoebae are not able to measure the direction from which the light comes, and di¡erences in light intensity do not lead to di¡erentiation in motion velocity among the amoebae. Nevertheless, the whole slug orientates itself towards the light. This behaviour is mediated by a modi¢cation of the cyclic AMP (cAMP) waves. As an explanation for phototaxis we propose the following mechanism, which is basically characterized by four processes: (i) light is focused on the distal side of the slug as a result of the so-called`lens-e¡ect'; (ii) di¡erences in luminous intensity cause di¡erences in NH 3 concentration; (iii) NH 3 alters the excitability of the cell, and thereby the shape of the cAMP wave; and (iv) chemotaxis towards cAMP causes the slug to turn. We show that this mechanism can account for a number of other behaviours that have been observed in experiments, such as bidirectional phototaxis and the cancellation of bidirectionality by a decrease in the light intensity or the addition of charcoal to the medium.

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Section: Discussionmentioning

confidence: 78%

“…During phototaxis the trails of slugs belonging to certain mutant strains can become unstable, bidirectional (Fisher & Williams 1981), or even multidirectional (Fisher et al 1985). We speci¢cally focus on the bidirectional mutants.…”

Section: Introductionmentioning

confidence: 99%

Phototaxis during the slug stage of Dictyostelium discoideum: a model study

Marée

Panfilov

Hogeweg

1999

Proc. R. Soc. Lond. B

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“…Phototaxis has been described in terms of a movement error correction mechanism, the molecular mechanism of which is largely unknown (Fisher et al, 1984(Fisher et al, , 1997). In our model, continuous error correction could presumably also result in straightforward movement.…”

Section: Slug Movementmentioning

confidence: 99%

A Model forDictyosteliumSlug Movement

Bretschneider

Vasiev

Weijer

1999

Journal of Theoretical Biology

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“…If the same were true for pertussis toxin, it might be difficult to detect a difference between thermotaxis in the presence and absence of the toxin. Alternatively, pertussis-toxin-sensitive G-protein(s) might be involved in slugs only in phototransduction, at a point before the signalling pathway converges with that for thermotaxis (Fisher et al, 1984). Taken together, the effects of fluoride and pertussis toxin indicate that G-proteins transduce extracellular signals in D. discoideum slug behaviour.…”

Section: Discussionmentioning

confidence: 96%

“…Although less widely studied, sensory transduction in the multicellular 'slug' stage of the D. discoideum life cycle seems to be based on the same molecular processes as in the unicellular amoeboid stage (Fisher et al, 1984). This leads to the expectation that G-proteins and phosphatidylinositol lipid metabolism might play a role in transmembrane signalling in D. discoideum slugs.…”

Section: Introductionmentioning

confidence: 98%

A Role for G-proteins and Inositol Phosphate Signalling in Dictyostelium discoideum Slug Behaviour

Darcy

Fisher

1989

Microbiology

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Phototaxis by Dictyostelium discoideum slugs was disoriented in the presence of pertussis toxin, suggesting a role for pertussis-toxin-sensitive G-proteins in slug behaviour. The decrease in orientation accuracy was dependent on the concentration of this bacterial toxin. Pertussis toxin did not significantly affect slug thermotaxis, while cholera toxin had no significant effects on either slug phototaxis or thermotaxis. The addition of micromolar concentrations of lithium salts (LiCl or LiBr) resulted in disorientation of both phototaxis and positive thermotaxis by slugs. The corresponding sodium salts had no effect on slug behaviour, confirming that the effects were specific to lithium ions. The effects of lithium ions suggest a role for inositol phosphates as possible second messengers in Dictyosteliurn slug behaviour. Except for slight impairment of thermotaxis by D-sphingosine, we found no effects on slug behaviour of either phorboll2-myristate 13-acetate or sphingolipids. We thus found little pharmacological evidence for a role in slug signal transduction of the diacylglycerol branch of the inositol lipid pathway.

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Bidirectional phototaxis by Dictyostelium discoideum slugs

Cited by 12 publications

References 8 publications

Phototaxis during the slug stage of Dictyostelium discoideum: a model study

Phototaxis during the slug stage of Dictyostelium discoideum: a model study

A Model forDictyosteliumSlug Movement

A Role for G-proteins and Inositol Phosphate Signalling in Dictyostelium discoideum Slug Behaviour

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