An actomyosin‐like substance from the plasmodium of a myxomycete

Loewy, Ariel G.

doi:10.1002/jcp.1030400109

Cited by 153 publications

(30 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Indeed Kriszat (27,28) has shown that the movements of Amoeba proteus are modified in the presence of ATP; and Loewy (33) has extracted an actomyosin type of protein from another amoeba, Pelomyxa, and shown that the properties of the gels are dependent on ATP. The work of Weber and his collaborators on glycerol-extracted fibroblasts (66) is also well known.…”

Section: Theoretical Considerations Of Structural Mechanisms In Contrmentioning

confidence: 99%

Fine Structure and Function in Stentor polymorphus

Randall

Jackson

1958

The Journal of Cell Biology

153

View full text Add to dashboard Cite

ABSTltACTThe fine structure of the ciliate Steutor has been studied by means of the electron microscope and the results have been correlated with observations made on the living organism by means of light microscopy; special reference has been made to structural features which may be responsible for contraction and extension in Stentor.Descriptions have been given of the structure of the macronncleus, the vacuolated cytoplasm, mitochondria and the pellicle; a detailed study has also been made of the adoral membranelles. About 250 membranelles encircle the peristomal cap and each is composed of 3 rows of cilia, with 20 to 25 cilia in each row; a fibrillar root system connected with the membranelles depends into the endoplasm for about 20 # and each is essentially in the shape of a fan, the terminal ends of each root bifurcating to connect to neighbouring roots. The membranelles thus form a cohesive unit and this morphological arrangement may have a bearing on the motion and coordination of the whole system. Two structural features extending throughout the length of the animal have been identified per cortical stripe in the body wall of Stentor; first, km fibres lying just beneath the pellicle are composed of stacks of fibrillar sheets and are identical with the birefringent fibres observed in the living animal. The individual fibrils of the sheets are in turn connected to the kinetosomes of the body cilia; thus the km fibres are homologous to kinetodesmata. Secondly, NI bands lie beneath the km fibres and form an interconnected system in contact with the surrounding vacuolated cytoplasm; the thickness of the M bands is greatest at the base of a contracted animal. The contractile and extensile properties of these organelles have been discussed in the light of experimental results and theoretical considerations.

show abstract

Section: Theoretical Considerations Of Structural Mechanisms In Contrmentioning

confidence: 99%

Fine Structure and Function in Stentor polymorphus

Randall

Jackson

1958

The Journal of Cell Biology

153

View full text Add to dashboard Cite

show abstract

“…ATP has been implicated as the energy souirce in various types of contractile systems, such as the amoeboid movement of the slime mold Physarutnt polycephalum11 (18), cilia of V7orticella (13), and, of course, muscle fibers (20). Thus it is not surprising that the pea tendrils, which contract during the first phase of contact coiling, are controlled by a similar mechanism.…”

Section: Resultsmentioning

confidence: 99%

Physiological Studies on Pea Tendrils. II. The Role of Light and ATP in Contact Coiling

Jaffe

Galston

1966

Plant Physiol.

View full text Add to dashboard Cite

Summiary. Excise (d pea (Pisul1t s(ati . L.) tencdrils inctibated in the light coil more than those incubated in the dark. This light effect, which displays spectral responses characteristic of chlorophyll-mediated mechanisms, is increased by at least 8 honirs of prior dark inctnbation of plants from which the tendrils were derived. Considerable evidence indicates a major role of ATP in coiling. For example, inhibitors of ATP produiction decrease contact coiling. Exogenonis ATP increases cutrvatnire in the (lark, Cturvature is proportional to the logarithm of the molarity of applied ATP between 10-4 and 10-2 M, whereas elongation responds only to the higher dosages. It is inferre(d that endogenotus ATP is involved as an energy souirce in coiling, especially in the initial phase, which involves contraction of the tendril. The existence of a higher plant analog of actomyosin, stuggested by others, is stipportedl.

show abstract

“…Such observ,ations indiciate that ATPase activity may be associated with the coiling of pea tendrils, as it is with muscle contraction (4), the movements of the plasmodium of Physarutmii polvcephalumi1t (3) and the rapid movements of M1im1iosa puidic(o leaves (T. Sibaoka, personal communication).…”

mentioning

confidence: 99%

“…Further evidence supporting the role of ATPase in coiling is the demTonstration of ATPase activity in,an extract that also displays the actomyosin-like property of visco-sity decrease in the presence of ATP. To the best of our knowledge this is the first demonstration of a contractile ATPase associated with the rapidly moving organ of a higher plant, although it has been found to exist in a slime mold (3) and in the vascular tissue of the leaves of various species (6).…”

mentioning

confidence: 99%