MICROFILAMENTS IN <i>CHAOS CAROLINENSIS  </i>

Comly, Lucy T.

doi:10.1083/jcb.58.1.230

Cited by 57 publications

(13 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Taylor and his co-workers (40) injected fluorescent-actin into rapidly moving amoebas and found that it also distributed diffusely in the streaming cytoplasm and the stationary cortex . These light microscope observations do not mean, however, that actin filaments are not involved, because electron micrographs reveal 90 THE JOURNAL Of CELL BIOLOGY -VOLUME 90,1981 actin filaments in the cortex of amoeba (13), as well as the cytoplasm of ruffling membranes (4,11,12,37,42) and the cleavage furrow (36).…”

Section: Discussionmentioning

confidence: 99%

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Herman¹,

Crisona²,

Pollard³

1981

The Journal of Cell Biology

219

103

View full text Add to dashboard Cite

We documented the activity of cultured cells on time-lapse videotapes and then stained these identified cells with antibodies to actin and myosin. This experimental approach enabled us to directly correlate cellular activity with the distribution of cytoplasmic actin and myosin. When trypsinized HeLa cells spread onto a glass surface, the cortical cytoplasm was the most actively motile and random, bleb-like extensions (0.5-4.0 micrometer wide, 2-5 micrometer long) occurred over the entire surface until the cells started to spread. During spreading, ruffling membranes were found at the cell perimeter. The actin staining was found alone in the surface blebs and ruffles and together with myosin staining in the cortical cytoplasm at the bases of the blebs and ruffles. In well-spread, stationary HeLa cells most of the actin and myosin was found in stress fibers but there was also diffuse antiactin fluorescence in areas of motile cytoplasm such as leading lamellae and ruffling membranes. Similarly, all 22 of the rapidly translocating embryonic chick cells had only diffuse actin staining. Between these extremes were slow-moving HeLa cells, which had combinations of diffuse and fibrous antiactin and antimyosin staining. These results suggest that large actomyosin filament bundles are associated with nonmotile cytoplasm and that actively motile cytoplasm has a more diffuse distribution of these proteins.

show abstract

Section: Discussionmentioning

confidence: 99%

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Herman¹,

Crisona²,

Pollard³

1981

The Journal of Cell Biology

219

103

View full text Add to dashboard Cite

show abstract

“…Thick and thin filaments have been found by others (4, 16, 18, 23) in glycerinated amebae and we confirm these observations. Comly (4) noted thin filaments in the ectoplasmic tube region of glycerinated C. chaos but observed no thick filaments. Thick and thin filaments, however, occurred in the endoplasm.…”

Section: Resultsmentioning

confidence: 96%

Contractility of Glycerinated Amoeba proteus and *Chaos‐chaos**

Rinaldi

Opas

Hrebenda

1975

The Journal of Protozoology

View full text Add to dashboard Cite

Immediate contact with large volumes of cold 50% (v/v) buffered glycerol preserved typical ameboid shape of Chaos chaos and Amoeba proteus with no visible distortions. These technics allowed determination of the contraction sites in these glycerinated models upon applications of ATP-Ca-Mg-solutions. The ectoplasmic tube was the main site of contraction. Preliminary EM investigations revealed thick and thin filaments, associated with the ectoplasmic tube near the plasma-lemma, which appeared to be the basis for the contractility of the ectoplasmic tube. There was no predominant contraction of the pseudopodial tips or the endoplasm in these models. The changes of volume were as much as 50%, and in some cases were not accompanied by any change in the length of the ameba; however, lengthwise contractions of the ectoplasmic tube in some amebae occurred to as much as 25%. The data substantiate a basic requirement of the ectoplasmic tube contraction theory of ameboid locomotion.

show abstract

“…With HMM labeling of thin filaments there was found a specific orientation of labeled filaments within the ectoplasmic tube positioned near and/or attached to the plasmalemma (1,13). With HMM labeling in ameba, thin filaments are beautifully illustrated but thick filaments are rarely found within the ectoplasmic tube (1,13). ATPase activity in contracting ameba has been reported (12,16,17,19).…”

Section: Discussionmentioning

confidence: 95%

Oriented thick and thin filaments in amoeba proteus

Rinaldi¹,

Hrebenda²

1975

The Journal of Cell Biology

View full text Add to dashboard Cite

Actin and myosin filaments as a foundation of contractile systems are well established from ameba to man (3). Wolpert et al. (19) isolated by differential centrifugation from Amoeba proteus a motile fraction composed of filaments which moved upon the addition of ATP. Actin filaments are found in amebas (1, 12, 13) which react with vertebrate heavy meromyosin (HMM), forming arrowhead complexes as vertebrate actin (3, 9), and are prominent within the ectoplasmic tube where some of them are attached to the plasmalemma (1, 12). Thick and thin filaments possessing the morphological characteristics of myosin and actin have been obtained from isolated ameba cytoplasm (18, 19). In addition, there are filaments exhibiting ATPase activity in amebas which react with actin (12, 16, 17). However, giant ameba (Chaos-proteus) shapes are difficult to preserve, and the excellent contributions referred to above are limited by visible distortions occurring in the amebas (rounding up, pseudopods disappearing, and cellular organelles swelling) upon fixation. Achievement of normal ameboid shape in recent glycerination work (15) led us to attempt other electron microscope fixation techniques, resulting in a surprising preservation of A. proteus with a unique orientation of thick and thin filaments in the ectoplasmic region.

show abstract

MICROFILAMENTS IN CHAOS CAROLINENSIS

Cited by 57 publications

References 36 publications

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Contractility of Glycerinated Amoeba proteus and *Chaos‐chaos**

Oriented thick and thin filaments in amoeba proteus

Contact Info

Product

Resources

About

MICROFILAMENTS IN CHAOS CAROLINENSIS

Cited by 57 publications

References 36 publications

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Relation between cell activity and the distribution of cytoplasmic actin and myosin.

Contractility of Glycerinated Amoeba proteus and Chaos‐chaos*

Oriented thick and thin filaments in amoeba proteus

Contact Info

Product

Resources

About

Contractility of Glycerinated Amoeba proteus and *Chaos‐chaos**