scholarly journals Scaling of caterpillar body properties and its biomechanical implications for the use of a hydrostatic skeleton

2011 ◽  
Vol 214 (7) ◽  
pp. 1194-1204 ◽  
Author(s):  
H.-T. Lin ◽  
D. J. Slate ◽  
C. R. Paetsch ◽  
A. L. Dorfmann ◽  
B. A. Trimmer
Keyword(s):  
Hydrostatic Skeleton

The locomotion of the acanthor of Moniliformis dubius (Archiacanthocephala)

Parasitology ◽  
1971 ◽  
Vol 62 (1) ◽  
pp. 35-47 ◽  
Author(s):  
P. J. Whitfield
Keyword(s):  
Intermediate Host ◽  
Body Wall ◽  
The Body ◽  
Research Fellowship ◽  
Wall Movement ◽  
Hydrostatic Skeleton ◽  
Laboratory Facilities ◽  
Longitudinal Muscles ◽  
Shape Changes

The mature egg and the acanthor of Moniliformis dubius have been redescribed with special emphasis on the features relevant to the locomotion of this larval acanthocephalan. The movements of acanthors have been analysed by the use of frame by frame study of filmed records of motile acanthors. Acanthors appear to use the same mode of locomotion for hatching, locomotion within the gut of the intermediate host and penetration of the host's gut wall. Movement is produced by a set of spiralled, longitudinal muscles in the body wall of the hind body and two rostellar retractor muscles. This musculature acts both directly on the body wall and indirectly by hydraulic effects via the hydrostatic skeleton of pseudocoelomic fluid. The spiny evertable rostellum and the backward facing spines of the hind body are the means whereby shape changes of the acanthor interact with the immediate environment to produce effective progression.I should like to thank Professor D. Arthur for the provision of laboratory facilities, Dr D. W. T. Crompton for the initial gift of eggs of M. dubius and Mr R. D. Reed for invaluable assistance with microcinematographic technique. The work was carried out during the tenure of a Nuffield Foundation Research Fellowship.

The Structure and Operation of the Obliquely Striated Supercontractile Somatic Muscles in Nematodes.

1983 ◽  
Vol 31 (5) ◽  
pp. 677 ◽  
Author(s):  
WG Inglis
Keyword(s):  
Striated Muscle ◽  
Striated Muscles ◽  
Insect Larvae ◽  
Hydrostatic Skeleton ◽  
Wide Range ◽  
Somatic Muscles

The structure of nematode somatic muscles is reviewed. They are obliquely striated and, therefore, supercontractile because they change in length to an exceptional extent by both myofilament interdigitation and shearing. A model is developed which shows that shearing is generated by interdigitation under specified structural conditions. It is concluded that the ability to supercontract is functionally associated with a hydrostatic skeleton, because obliquely striated muscles occur in a wide range of unrelated Phyla and a functionally identical muscle has evolved from cross-striated muscle in other animals with a hydrostatic skeleton, particularly certain insect larvae. Two, possibly 3, morphologically distinct groups of muscles exist in the Nematoda which correspond to the Classes Enoplea, Rhabditea and Chromadorea. Parallel sequences of change occur in the first 2, in which the contractile layer increases in area, the sarcomeres become smaller, and the Z-system more regular. Descriptive terms are redefined, thus: platymyarian, quasi-platymyarian, shallow coelomyarian, and coelomyarian occur in Rhabditea; cubomyarian, regular cubomyarian, and stratimyarian occur in Enoplea; and a characteristic chromadorid-circomyarian is known from 2 Chromadorea. The structure of the muscles corresponds well to the higher nematode classification, except in the Order Spirurida which may have arisen from the Enoplea and not the Rhabditea as generally accepted.

CYTOPLASMIC BRIDGES AND MUSCLE SYSTEMS IN SOME POLYMYARIAN NEMATODES

1966 ◽  
Vol 44 (2) ◽  
pp. 329-340 ◽  
Author(s):  
K. A. Wright
Keyword(s):  
Electron Microscope ◽  
Muscle Cell ◽  
Light Microscope ◽  
Muscular Activity ◽  
Muscle Cells ◽  
Serial Sections ◽  
Cell Systems ◽  
Hydrostatic Skeleton ◽  
Cytoplasmic Bridges ◽  
Somatic Musculature

The somatic musculature of nine genera of nematodes (Contracaecum, Toxascaris, Toxocara, Porrocaecum, Cyslidicola, Amplicaecum, Physaloptera, Thoracostoma, and Dermatoxys) was examined by means of serial sections and dissections examined with the light microscope, and, in one instance (Thoracostoma), by use of an electron microscope. Interconnections between muscle cells (cytoplasmic bridges) were demonstrated in the musculature of the polymyarian nematodes, but could not be seen in Dermatoxys, the only meromyarian nematode studied. Cytoplasmic bridges occur in greater frequency in the anterior end of the nematodes. Innervation processes of muscle cells frequently branch before they associate with the median chords. In the head end of Toxascaris, Toxocara, and Porrocaecum, muscle cells are doubly innervated, sending innervation processes to sublateral nerve cords as well as to the median hypodermal chords. Cytoplasmic bridges probably are the basis of the electrical pathways by which contraction impulses are spread from cell to cell. The complexly interconnected muscle cell systems demonstrated undoubtedly serve, along with the nematode's hydrostatic skeleton, as the mechanism by which coordinated muscular activity is achieved.

Sign in / Sign up

Export Citation Format

Share Document