Cytoplasmic filaments and cellular wound healing in amoeba proteus

Jeon, KW; Jeon, Oc-Yeub

doi:10.1083/jcb.67.1.243

Cited by 66 publications

(25 citation statements)

References 15 publications

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“…The large number of microfilaments observed by Jeon and Jeon (14) during wound healing were most likely actin and myosin filaments involved in cortical contractions . These cortical contractions can be viewed as an intracellular "clotting" mechanism because the cytoplasm is kept from emptying out of the cell.…”

Section: Distribution Of Actin In Living Cellsmentioning

confidence: 99%

“…Jeon and Jeon (14) demonstrated that amebas responded to puncture wounds by forming or recruiting a large number of microfilaments at the site of damage in the cell cortex . In the present investigation, a wound-healing response was induced by micropuncture after the incorporation of labeled proteins.…”

Section: Redistribution Of Actin After Experimental Manipulationmentioning

confidence: 99%

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Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Taylor¹,

Wang²,

Heiple³

1980

The Journal of Cell Biology

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The technique of molecular cytochemistry has been used to follow the distribution of fluorescently labeled actin in living Chaos carolinensis and Amoeba proteus during ameboid movement and various cellular processes. The distribution of 5-iodoacetamidofluorescein-labeled actin was compared with that of Lissamine rhodamine B sulfonyl chloride-labeled ovalbumin microinjected into the same cell and recorded with an image intensification microscope system. Actively motile cells demonstrated a rather uniform distribution of actin throughout most of the cytoplasm, except in the tail ectoplasm and in plasma gel sheets, where distinct actin structures were observed. In addition, actin-containing structures were induced in the cortex during wound healing, concanavalin A capping, pinocytosis, and contractions elicited by phalloidin injections. The formation of distinct fluorescent actin structures has been correlated with contractile activities.

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Section: Distribution Of Actin In Living Cellsmentioning

confidence: 99%

Section: Redistribution Of Actin After Experimental Manipulationmentioning

confidence: 99%

Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Taylor¹,

Wang²,

Heiple³

1980

The Journal of Cell Biology

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“…Damaging the plasmalemma and underlying cortex has been shown to induce a wound-healing contraction of the cortical actin and myosin (35,72) . Damaging the aequorin-injected cells in Marshall's solution by micropuncture resulted in intense localized increases in luminescence at the sites of damage that spread only a few microns from the wounds (Fig .…”

Section: Stimulated Pulses Of Luminescencementioning

confidence: 99%

Contractile basis of ameboid movement. VII. Aequorin luminescence during ameboid movement, endocytosis, and capping.

Taylor¹,

Blinks²,

Reynolds³

1980

The Journal of Cell Biology

127

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Aequorin luminescence has been utilized to determine the spatial and temporal fluctuations of the free calcium ion concentration [Ca"] in Chaos carolinensis during ameboid movement, pinocytosis, and capping. The [Ca"] increases above _10-7 M during normal ameboid movement . Three types of luminescent signals are detected in cells: continuous luminescence, spontaneous pulses, and stimulated pulses . Continuous luminescence is localized in the tails of actively motile cells, and spontaneous pulses occur primarily over the anterior regions of cells. We are sometimes able to correlate the spontaneous pulses with extending pseudopods, whereas stimulated pulses are induced by mechanical damage, electrical stimulation, concanavalin A-induced capping, and pinocytosis. The localization of both distinct actin structures and sites where [Ca"] increases suggests cellular sites of contractile activity . The independent evidence from localizing actin structures and the distribution of [Ca"] can also be viewed in relation to the solation-contraction coupling hypothesis defined in vitro.Calcium regulation of cytoplasmic structure and contractility in ameboid cells was first identified in single cell models from Chaos carolinensis (66) . The calcium regulation of both gelation and contraction was subsequently described in bulk cell-free extracts (21, 68, 69), in partially reconstituted models (31), and in single living cells (70) . Recently, a high-affinity calciumbinding protein which regulates gelation and plays a role in regulating contraction (77) (see references 73 and 74 for reviews) has been isolated from Dictyostelium discoideum . Evidence for calcium regulation of cytoplasmic structure and/or contractility has also been demonstrated in cell models from other ameboid cells, including Acanthamoeba (50), Ehrlich tumor cells (45), and macrophages (78). In addition, a great deal of indirect evidence has also supported the suggestion that calcium regulates at least some of the events involved in ameboid movements (see references 33 and 74 for reviews) .A direct identification of fluctuations in the free calcium ion concentration in living cells is necessary to identify calcium as a physiologically relevant intracellular messenger involved in cell motility . This is especially true because other parameters, including changes in pH, can also affect cytoplasmic structure THE JOURNAL of CELT BIOLOGY -VOLUmE 86 AUGUST 1980 599-607 ©The Rockefeller University Press -0021-9525/80/08/0599/09 $1 .00 and contractility in vitro (21, 68, 69).' Ultimately, a map of the spatial and temporal distribution of all potential regulatory factors must be constructed and correlated with motile behavior in living cells.Aequorin luminescence (9-11, 56, 60, 61) has been used as a highly sensitive indicator of intracellular free calcium in several types of cells (see references 9, 10 and 56 for reviews) . The high signal to noise ratio, relative specificity for Ca", lack of toxicity, and ease of signal detection have made this technique attr...

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“…The D and xD strains of A. proteus were cultured in a modified Chalkley's solution (Jeon and Jeon, 1975) in Pyrex baking dishes (35×22×4 cm). Amoebae were fed daily with axenically cultured and washed Tetrahymena pyriformis as food organisms (Goldstein and Ko, 1976).…”

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confidence: 99%

DNA adenine methylation of sams1 gene in symbiont-bearing Amoeba proteus

Jeon

2008

J Microbiol.

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The expression of amoeba sams genes is switched from sams1 to sams2 when amoebae are infected with Legionella jeonii. To elucidate the mechanism for the inactivation of host sams1 gene by endosymbiotic bacteria, methylation states of the sams1 gene of D and xD amoebae was compared in this study. The sams1 gene of amoebae was methylated at an internal adenine residue of GATC site in symbiont-bearing xD amoebae but not in symbiont-free D amoebae, suggesting that the modification might have caused the inactivation of sams1 in xD amoebae. The sams1 gene of xD amoebae was inactivated at the transcriptional level. Analysis of DNA showed that adenine residues in L. jeonii sams were also methylated, implying that L. jeonii bacteria belong to a Dam methylase-positive strain. In addition, both SAM and Met appeared to act as negative regulators for the expression of sams1 whereas the expression of sams2 was not affected in amoebae.

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Cytoplasmic filaments and cellular wound healing in amoeba proteus

Cited by 66 publications

References 15 publications

Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Contractile basis of ameboid movement. VII. The distribution of fluorescently labeled actin in living amebas.

Contractile basis of ameboid movement. VII. Aequorin luminescence during ameboid movement, endocytosis, and capping.

DNA adenine methylation of sams1 gene in symbiont-bearing Amoeba proteus

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