Abstract
Laser light scattered from particles in the streaming protoplasm of a living cell is shifted in frequency by the Doppler effect. The spectrum of the scattered light can be measured and interpreted to infer details of the velocity distribution in the protoplasm. We have developed this approach to study the protoplasmic streaming in the fresh-water alga Nitella. Our results indicate a characteristic flow pattern to which diffusion makes a negligible contribution. No difference in the velocity of particles of different size is indicated. The streaming velocity linearly with temperature with a supraoptimal temperature of 34 degrees C, and the velocity distribution becomes narrower at high temperatures. The protoplasmic streaming can be inhibited by laser light, and this effect has been used to study the photoresponse of the algae. Using beam diameters of about 50 mum, we have shown that the inhibition is very local, becoming minimal at a displacement of about 200 mum in the upstream direction and 400 mum in the downstream direction. Prolonged exposure produces a bleached area free of chloroplasts, which is three orders of magnitude less sensitive to photoinhibition.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen N. S. Endoplasmic filaments generate the motive force for rotational streaming in Nitella. J Cell Biol. 1974 Oct;63(1):270–287. doi: 10.1083/jcb.63.1.270. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Andrianov V. K., Kurella G. A., Litvin F. F. Izmenenie potentsiala kletok vodorosli Nitella pri destvii sveta i sviaz'étogo éffekta s fotosintezom. Biofizika. 1965;10(3):531–533. [PubMed] [Google Scholar]
- Barr C. E., Broyer T. C. Effect of Light on Sodium Influx, Membrane Potential, and Protoplasmic Streaming in Nitella. Plant Physiol. 1964 Jan;39(1):48–52. doi: 10.1104/pp.39.1.48. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dubin S. B., Lunacek J. H., Benedek G. B. Observation of the spectrum of light scattered by solutions of biological macromolecules. Proc Natl Acad Sci U S A. 1967 May;57(5):1164–1171. doi: 10.1073/pnas.57.5.1164. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hansen U. P., Warncke J., Keunecke P. Photoelectric effects in characean cells. I. The influence of light intensity. Biophysik. 1973 May 30;9(3):197–202. doi: 10.1007/BF01184685. [DOI] [PubMed] [Google Scholar]
- Kamitsubo E. A 'window technique' for detailed observation of characean cytoplasmic streaming. Exp Cell Res. 1972 Oct;74(2):613–616. doi: 10.1016/0014-4827(72)90430-2. [DOI] [PubMed] [Google Scholar]
- Nagai R., Rebhun L. I. Cytoplasmic microfilaments in streaming Nitella cells. J Ultrastruct Res. 1966 Mar;14(5):571–589. doi: 10.1016/s0022-5320(66)80083-7. [DOI] [PubMed] [Google Scholar]
- Palevitz B. A., Hepler P. K. Identification of actin in situ at the ectoplasm-endoplasm interface of Nitella. Microfilament-chloroplast association. J Cell Biol. 1975 Apr;65(1):29–38. doi: 10.1083/jcb.65.1.29. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tanaka T., Riva C., Ben-Sira B. Blood velocity measurements in human retinal vessels. Science. 1974 Nov 29;186(4166):830–831. doi: 10.1126/science.186.4166.830. [DOI] [PubMed] [Google Scholar]
- Tazawa M. Motive force of the cytoplasmic streaming in nitella. Protoplasma. 1968;65(1):207–222. doi: 10.1007/BF01666379. [DOI] [PubMed] [Google Scholar]
- Volkov G. A. Bioelectrical response of the Nitella flexilis cell to illumination: a new possible state of plasmalemma in a plant cell. Biochim Biophys Acta. 1973 Jul 26;314(1):83–92. doi: 10.1016/0005-2728(73)90066-2. [DOI] [PubMed] [Google Scholar]
- Williamson R. E. Cytoplasmic streaming in Chara: a cell model activated by ATP and inhibited by cytochalasin B. J Cell Sci. 1975 May;17(3):655–668. doi: 10.1242/jcs.17.3.655. [DOI] [PubMed] [Google Scholar]