Involvement of protein synthesis in recovery from refractory period of electrical depolarization induced by osmotic stimulation in Chara corallina

Shimmen, Teruo

doi:10.1007/s10265-010-0391-9

Cited by 3 publications

References 39 publications

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Electrophysiology of the Detached Cell Under Stress

Beilby

Casanova

2013

The Physiology of Characean Cells

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This chapter summarises the research on characean detached cells, subjected to calibrated and primarily abiotic types of stress. Responses to touch, wounding, voltage clamp to both depolarised and hyperpolarised potential difference (PD) levels and to osmotic and saline stress are described. Both salt-tolerant and saltsensitive Characeae have been investigated under osmotic and saline stress. Many of the cell responses involve an increase in cytoplasmic calcium concentration. However, the manner of calcium increase is specific to different stressors: mechanical stimulation opens stretch-activated (SA) channels on internal stores, depolarisation to excitation threshold opens IP 6 -activated channels on internal stores, hypo-osmotic stress opens SA channels on internal stores and possibly the vacuole, hyperpolarisation opens channels on the plasma membrane. The increase in the calcium concentration in the cytoplasm opens calcium-activated chloride channels on the plasma membrane (and possibly the tonoplast), leading to an outflow of chloride and depolarisation that can take a form of receptor potential (RPD), action potential (AP) or variation potential (VP). From all these responses, the AP fits the role of a signal: its form is relatively constant and it can propagate speedily from cell to cell. The responses to hyperosmotic and saline stress show interesting differences between salt-tolerant and salt-sensitive Characeae. In salt-tolerant Characeae, the proton pump is activated by both a decrease in turgor and an increase in salinity. The activation by turgor decrease is transient as turgor is regulated, while activation by salt is permanent and graded according to salt concentration. The turgor sensors may be located at the ends of nodal cells. In salt-sensitive Characeae, on the other hand, non-plasmolysing turgor decrease elicits no change in pump activity, while an increase in salinity shuts down the pump and opens H + /OH À channels, depolarising the membrane PD further. Spontaneous APs with long durations and opening of outward rectifying channels lead to a loss of potassium and death. Both salt-sensitive and salt-tolerant Characeae employ Na + /H + antiporter to remove Na + from the cytoplasmic compartment under saline stress and the water channels on the plasma membrane are closed by high osmolarity.

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Electrophysiology of the Detached Cell Under Stress

Beilby

Casanova

2013

The Physiology of Characean Cells

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Further electrophysiological studies on cellular effect of herbicide, bromoxynil, using characean cells

Shimmen

2012

J Plant Res

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In the previous paper, I reported that 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) depolarizes the plasma membrane by inhibiting the electrogenic proton pump and discussed that the inhibition is caused by cytosol acidification due to influx of protonated bromoxynil and following release of proton (Shimmen in J Plant Res 123:715-722, 2010). However, a possibility of direct inhibition of the proton pump by bromoxynil flowed into the cell could not be excluded. In the present study, the direct effect of bromoxynil on the proton pump was unequivocally excluded.

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Transduction of pressure signal to electrical signal upon sudden increase in turgor pressure in Chara corallina

Shimmen

Ogata

2012

J Plant Res

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By taking advantage of large cell size of Chara corallina, we analyzed the membrane depolarization induced by decreased turgor pressure (Shimmen in J Plant Res 124:639-644, 2011). In the present study, the response to increased turgor pressure was analyzed. When internodes were incubated in media containing 200 mM dimethyl sulfoxide, their intracellular osmolality gradually increased and reached a steady level after about 3 h. Upon removal of dimethyl sulfoxide, turgor pressure quickly increased. In response to the increase in turgor pressure, the internodes generated a transient membrane depolarization at its nodal end. The refractory period was very long and it took about 2 h for full recovery after the depolarizing response. Involvement of protein synthesis in recovery from refractoriness was suggested, based on experiments using inhibitors.

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Involvement of protein synthesis in recovery from refractory period of electrical depolarization induced by osmotic stimulation in Chara corallina

Cited by 3 publications

References 39 publications

Electrophysiology of the Detached Cell Under Stress

Electrophysiology of the Detached Cell Under Stress

Further electrophysiological studies on cellular effect of herbicide, bromoxynil, using characean cells

Transduction of pressure signal to electrical signal upon sudden increase in turgor pressure in Chara corallina

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