%0 Journal Article %1 RN1145 %A Sukhorukov, V. L. %A Endter, J. M. %A Zimmermann, D. %A Shirakashi, R. %A Fehrmann, S. %A Kiesel, M. %A Reuss, R. %A Becker, D. %A Hedrich, R. %A Bamberg, E. %A Roitsch, T. %A Zimmermann, U. %D 2007 %J Biophysical Journal %K calcium free myOwn %N 9 %P 3324-3337 %R DOI 10.1529/biophysj.107.110783 %T Mechanisms of electrically mediated cytosolic Ca transients in Aequorin-Transformed tobacco cells %U /brokenurl#<Go to ISI>://WOS:000250199300037 %V 93 %X Cytosolic Ca2+ changes induced by electric. field pulses of 50-mu s duration and 200-800 V/cm strength were monitored by measuring chemiluminescence in aequorin-transformed BY-2 tobacco cells. In Ca2+-substituted media, electropulsing led to a very fast initial increase of the cytosolic Ca2+ concentration reaching a peak value within < 100-200 ms. Peaking of Ca2+(cyt) was followed by a biphasic decay due to removal of Ca2+ (e. g., by binding and/or sequestration in the cytosol). The decay had fast and slow components, characterized by time constants of; similar to 0.5 and 3-5 s, respectively. Experiments with various external Ca2+ concentrations and conductivities showed that the fast decay arises from Ca2+ fluxes through the plasmalemma, whereas the slow decay must be assigned to Ca2+ fluxes through the tonoplast. The amplitude of the Ca2+(cyt) transients increased with increasing. field strength, whereas the time constants of the decay kinetics remained invariant. Breakdown of the plasmalemma was achieved at a critical. field strength of similar to 450 V/cm, whereas breakdown of the tonoplast required similar to 580 V/cm. The above. finndings could be explained by the transient potential profiles generated across the two membranes in response to an exponentially decaying. field pulse. The dielectric data required for calculation of the tonoplast and plasmalemma potentials were derived from electrorotation experiments on isolated vacuolated and evacuolated BY-2 protoplasts. The electrorotation response of vacuolated protoplasts could be described in terms of a three-shell model (i.e., by assuming that the capacitances of tonoplast and plasmalemma are arranged in series). Among other things, the theoretical analysis together with the experimental data show that genetic manipulations of plant cells by electrotransfection or electrofusion must be performed in low-conductivity media to minimize release of vacuolar Ca2+ and presumably other vacuolar ingredients.

@article{RN1145, abstract = {Cytosolic Ca2+ changes induced by electric. field pulses of 50-mu s duration and 200-800 V/cm strength were monitored by measuring chemiluminescence in aequorin-transformed BY-2 tobacco cells. In Ca2+-substituted media, electropulsing led to a very fast initial increase of the cytosolic Ca2+ concentration reaching a peak value within < 100-200 ms. Peaking of [Ca2+](cyt) was followed by a biphasic decay due to removal of Ca2+ (e. g., by binding and/or sequestration in the cytosol). The decay had fast and slow components, characterized by time constants of; similar to 0.5 and 3-5 s, respectively. Experiments with various external Ca2+ concentrations and conductivities showed that the fast decay arises from Ca2+ fluxes through the plasmalemma, whereas the slow decay must be assigned to Ca2+ fluxes through the tonoplast. The amplitude of the [Ca2+](cyt) transients increased with increasing. field strength, whereas the time constants of the decay kinetics remained invariant. Breakdown of the plasmalemma was achieved at a critical. field strength of similar to 450 V/cm, whereas breakdown of the tonoplast required similar to 580 V/cm. The above. finndings could be explained by the transient potential profiles generated across the two membranes in response to an exponentially decaying. field pulse. The dielectric data required for calculation of the tonoplast and plasmalemma potentials were derived from electrorotation experiments on isolated vacuolated and evacuolated BY-2 protoplasts. The electrorotation response of vacuolated protoplasts could be described in terms of a three-shell model (i.e., by assuming that the capacitances of tonoplast and plasmalemma are arranged in series). Among other things, the theoretical analysis together with the experimental data show that genetic manipulations of plant cells by electrotransfection or electrofusion must be performed in low-conductivity media to minimize release of vacuolar Ca2+ and presumably other vacuolar ingredients.}, added-at = {2024-02-14T14:38:32.000+0100}, author = {Sukhorukov, V. L. and Endter, J. M. and Zimmermann, D. and Shirakashi, R. and Fehrmann, S. and Kiesel, M. and Reuss, R. and Becker, D. and Hedrich, R. and Bamberg, E. and Roitsch, T. and Zimmermann, U.}, biburl = {https://www.bibsonomy.org/bibtex/228c53ee39dcd82b35360639c3e2f153e/rainerhedrich_2}, doi = {DOI 10.1529/biophysj.107.110783}, interhash = {a76f485c4d2760a1a429c578a08f6c44}, intrahash = {28c53ee39dcd82b35360639c3e2f153e}, issn = {0006-3495}, journal = {Biophysical Journal}, keywords = {calcium free myOwn}, note = {221ar Times Cited:8 Cited References Count:52}, number = 9, pages = {3324-3337}, timestamp = {2024-02-14T14:38:32.000+0100}, title = {Mechanisms of electrically mediated cytosolic Ca transients in Aequorin-Transformed tobacco cells}, type = {Journal Article}, url = {/brokenurl#<Go to ISI>://WOS:000250199300037}, volume = 93, year = 2007 }