Ca2+-induced tension development in the stalks of glycerinatedVorticella convallaria

Moriyama, Yasushige; Ishiwata, Shin’ichi; Asai, Hiroshi

doi:10.1002/(sici)1097-0169(1996)34:4<271::aid-cm2>3.0.co;2-b

Cited by 17 publications

(23 citation statements)

References 18 publications

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“…So isolation decreased the contractile ability by 6% (81/86 ϭ 94%) of its initial value. In V. convallaria the tension of the isolated spasmoneme was decreased by over 90% by isolation (Moriyama et al, 1996). The diameter of giant Zoothamnium spasmoneme (30 m) is much larger than that of Vorticella (1 m) and Carchesium (5 m), so the damage during isolation is thought to be very small.…”

Section: Little Damage To Spasmoneme By Isolation From the Outer Sheathmentioning

confidence: 99%

“…But in giant Zoothamnium, the birefringence of extended spasmoneme is very weak (0.2 ϫ 10 Ϫ3 ), whereas that of Carchesium is 4 ϫ 10 Ϫ3 (Weis-Fogh and Amos, 1972;Amos, 1975). Both extended and contracted spasmoneme of Vorticellid ciliates have high elasticity (Weis-Fogh and Amos, 1972;Moriyama et al, 1996;Asai et al, 1998); thus, spasmoneme is thought to be a rubber-like substance that changes its length with changes in [Ca 2ϩ ].…”

Section: Introductionmentioning

confidence: 99%

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Rubber-Like Elasticity and Volume Changes in the Isolated Spasmoneme of Giant Zoothamnium sp. under Ca2+-Induced Contraction

Moriyama

Okamoto

Asai

1999

Biophysical Journal

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Using glycerinated spasmoneme of giant Zoothamnium sp., the physical properties of spasmoneme before and after Ca2+-induced contraction (pCa 4.5) were investigated. The volume change of spasmoneme contraction was measured under zero tension. The length and diameter decreased by about 50% of their initial value as a result of contraction, which means that contraction is nearly isotropic. Thus the volume of spasmoneme decreased drastically by 86% of its original value. The swollen ratio of extended and contracted spasmoneme were 0.07 and 0.37, respectively. Tension-extension relationships of extended and contracted spasmonemes were measured. By applying the theory of rubber elasticity, the number of segments of a chain in originally extended spasmoneme was only 3.3, i.e., the chain was almost a straight one. On the other hand, the number of segments of a chain in contracted spasmoneme was more than 100, i.e., the chain was essentially a random one. Furthermore, the total number of chains in single spasmoneme was the same in extended and contracted spasmoneme. This means that the interchain cross-links of chains were not influenced by addition or removal of Ca2+. Moreover, the molecular weight of a chain is estimated to be at most about 50 kd. By considering all these results, it is concluded that the contractile mechanism of spasmoneme originates in the intramolecular folding and unfolding induced by Ca2+ binding and detaching.

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Section: Little Damage To Spasmoneme By Isolation From the Outer Sheathmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rubber-Like Elasticity and Volume Changes in the Isolated Spasmoneme of Giant Zoothamnium sp. under Ca2+-Induced Contraction

Moriyama

Okamoto

Asai

1999

Biophysical Journal

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“…For the purposes of both understanding the mechanism and attempting to copy it, many studies have aimed to define the parameters of Vorticella's movement and force production. High‐speed recordings of live cell contractions by Moriyama et al .…”

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confidence: 99%

“…For the purposes of both understanding the mechanism and attempting to copy it, many studies [5,9,11,13,[15][16][17][18][19][20][21][22] have aimed to define the parameters of Vorticella's movement and force production. Highspeed recordings of live cell contractions by Moriyama et al revealed the onset and time course of contraction [20], information which has been used in straightforward calculations of contraction force from Stokes' drag on a sphere.…”

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confidence: 99%

Direct measurement of Vorticella contraction force by micropipette deflection

Tejada

Matsudaira

2017

FEBS Letters

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The ciliated protozoan Vorticella convallaria is noted for its exceptionally fast adenosine triphosphate-independent cellular contraction, but direct measurements of contractile force have proven difficult given the length scale, speed, and forces involved. We used high-speed video microscopy to image live Vorticella stalled in midcontraction by deflection of an attached micropipette. Stall forces correlate with both distance contracted and the resting stalk length. Estimated isometric forces range from 95 to 177 nanonewtons (nN), or 1.12 nN·μm of the stalk. Maximum velocity and work are also proportional to distance contracted. These parameters constrain proposed biochemical/physical models of the contractile mechanism.

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“…Moriyama et al 10 measured the traction forces of Vorticella with a glass needle. The maximum isometric tension of Vorticella convallaria is 4 ϫ 10 −8 N. For live cell measurement, high speed video acquisition is the primary means of characterizing the contraction because the rapid movement of Vorticella is not readily amenable to other methods of study.…”

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confidence: 99%

Contraction and extension of Vorticella and its mechanical characterization under flow loading

2010

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We have studied the contraction and extension of Vorticella convallaria and its mechanical properties with a microfluidic loading system. Cells of V. convallaria were injected to a microfluidic channel ͑500 m in width and 100 m in height͒ and loaded by flow up to ϳ350 mm s −1 . The flow produced a drag force on the order of nanonewton on a typical vorticellid cell body. We gradually increased the loading force on the same V. convallaria specimen and examined its mechanical property and stalk motion of V. convallaria. With greater drag forces, the contraction distance linearly decreased; the contracted length was close to around 90% of the stretched length. We estimated the drag force on Vorticella in the channel by calculating the force on a sphere in a linear shear flow.

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Ca2+-induced tension development in the stalks of glycerinatedVorticella convallaria

Cited by 17 publications

References 18 publications

Rubber-Like Elasticity and Volume Changes in the Isolated Spasmoneme of Giant Zoothamnium sp. under Ca2+-Induced Contraction

Rubber-Like Elasticity and Volume Changes in the Isolated Spasmoneme of Giant Zoothamnium sp. under Ca2+-Induced Contraction

Direct measurement of Vorticella contraction force by micropipette deflection

Contraction and extension of Vorticella and its mechanical characterization under flow loading

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