Neural control of behaviour in Ascaris

Stretton, A. O. W.; Davis, Roger T.; Angstadt, James D.; Donmoyer, Judith E.; Johnson, Carl D.

doi:10.1016/0166-2236(85)90105-5

Cited by 59 publications

(27 citation statements)

References 20 publications

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“…The 15-protofilament microtubules may function, actively or passively, in the generation of signals (Chalfie and Thomson 1982). Motor neurons in the large nematode Ascaris do not produce action potentials, only graded potentials (Stretton et al 1985). If the touch cells in C. elegans act similarly, the magnitude of the signal may be so reduced in hypomorphic mec-7 mutants that it cannot reach the synapses unless generated very near to them; or these mutants may contain less stable microtubules that can be stabilized by proteins found preferentially near the synapses.…”

Section: Position Dependence Of Touch Sensitivitymentioning

confidence: 99%

mec-7 is a beta-tubulin gene required for the production of 15-protofilament microtubules in Caenorhabditis elegans.

Savage¹,

Hamelin²,

Culotti³

et al. 1989

Genes Dev.

295

185

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In the nematode Caenorhabditis elegans, microtubules with 15 protofilaments are a specialized feature of six touch-receptor neurons; microtubules found in other C. elegans neurons have 11 protofilaments. Mutations in the gene mec-7 result in touch-insensitive animals whose touch cells lack the 15-protofilament microtubules. We have characterized 54 mutations in the mec-7 gene. The absence of mec-7 activity results selectively in the recessive loss of touch sensitivity. Partial loss-of-function alleles result in a partial loss of touch sensitivity. Dominant mutations, which are isolated at an unusually high proportion, may encode abnormal products. We have cloned the mec-7 gene; it encodes a 13-tubulin which is 90-93% identical to vertebrate 13-tubulin. Our results are consistent with the hypothesis that tubulin heterogeneity contributes to the formation of structurally and functionally distinct sets of microtubules.

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Section: Position Dependence Of Touch Sensitivitymentioning

confidence: 99%

mec-7 is a beta-tubulin gene required for the production of 15-protofilament microtubules in Caenorhabditis elegans.

Savage¹,

Hamelin²,

Culotti³

et al. 1989

Genes Dev.

295

185

View full text Add to dashboard Cite

show abstract

“…Based in part on data from related nematodes, in which direct recording from neurons is possible, a model of the generic nematode segmental oscillator (Fig. 6B) was proposed 69 . This circuit bears a distinct resemblance to the simple halfcenter oscillator in Fig.…”

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confidence: 99%

Swimming at low Reynolds number: a beginners guide to undulatory locomotion

Cohen

Boyle

2010

Contemporary Physics

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Undulatory locomotion is a means of self-propulsion that relies on the generation and propagation of waves along a body. As a mode of locomotion it is primitive and relatively simple, yet can be remarkably robust. No wonder then, that it is so prevalent across a range of biological scales from motile bacteria to gigantic prehistoric snakes. Key to understanding undulatory locomotion is the body's interplay with the physical environment, which the swimmer or crawler will exploit to generate propulsion, and in some cases, even to generate the underlying undulations. This review focuses by and large on undulators in the low Reynolds numbers regime, where the physics of the environment can be much more tractable. We review some key concepts and theoretical advances, as well as simulation tools and results applied to selected examples of biological swimmers. In particular, we extend the discussion to some simple cases of locomotion in non-Newtonian media as well as to small animals, in which the nervous system, motor control, body properties and the environment must all be considered to understand how undulations are generated and modulated. To conclude, we review recent progress in microrobotic undulators that may one day become commonplace in applications ranging from toxic waste disposal to minimally invasive surgery.

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“…Ascaris suum has approximately 50 000 muscle cells along its 30 cm length and has 300 neurons, about 90 of which are involved in locomotion (for more on the neuromuscular anatomy, see Stretton et al 1985, and the references therein). Each muscle cell has a contractile spindle, the typical length being about 2 mm (Stretton, 1976).…”

Section: Methodsmentioning

confidence: 99%

“…The influence of neurons on the musculature is described in many of the papers from the Stretton laboratory (cf. Stretton et al 1985;Davis & Stretton, 1996; and the references therein). If there were no evidence for spontaneous muscle oscillation the 'neuron-to-muscle' path would underlie a model for locomotion.…”

mentioning

confidence: 99%

A Model for an Ascaris Muscle Cell

Turner¹

2001

Experimental Physiology

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Muscle cells in the nematode Ascaris suum undergo bouts of oscillation in the behaving worm, these being correlated with progressing waves of contraction along the body of the worm. The bouts have three time scales: a rough period of 7‐20 s, 10‐20 short bursts of spikes within a bout, and three to eight spikes per burst. This paper has two aims: showing that there is consistency between measurements of individual currents and measurements on whole muscle cells, and creating a building block to eventually explain the locomotion in this ‘simple’ system. A realistic model for a single Ascaris suum muscle cell is developed using existing data from experiments which have established the types of ionic currents in the muscle cell and many of their kinetic properties. Numerical simulations are carried out. The model cell reproduces the two shorter time scales present. It has some robustness with regard to parameter changes, but also allows for the different numbers of spikes per burst seen in recordings from muscle cells. The third time scale, the length of a bout, may originate from some system effect, a combination of neural and stretch effects and possibly a secondary effect of the calcium‐activated chloride channel.

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Neural control of behaviour in Ascaris

Cited by 59 publications

References 20 publications

mec-7 is a beta-tubulin gene required for the production of 15-protofilament microtubules in Caenorhabditis elegans.

mec-7 is a beta-tubulin gene required for the production of 15-protofilament microtubules in Caenorhabditis elegans.

Swimming at low Reynolds number: a beginners guide to undulatory locomotion

A Model for an Ascaris Muscle Cell

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