Abstract
When grown in medium containing dl-lactate at 27 C in the light, Euglena gracilis Z populations underwent modifications of the pigment system in response to 0.05 to 250 micromolar 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU).
Chlorophyll content dropped dramatically, the only remaining form being Chl a673. Light-driven O2 evolution was no longer detectable for the two highest DCMU concentrations tested. The energy-capture cross-section of detectable photosystem II units remained unchanged, although intersystem energy transfer no longer occurred. Euglena at this stage had chloroplast membranes destacked and swollen. A recovery phase then occurred, marked by enhanced photosynthetic properties. The initial forms of chlorophyll which were accumulated were highly efficient for O2 evolution. The newly formed photosystem II antennae were connected and of small size. Finally, the third phase involved the recovery of photosynthetic capacity similar to that of the controls as the thylakoids regained their normal structures.
Since these modifications occurred in the entire population and DCMU resistance persisted through successive cell generations, these adapted Euglena were considered to be a variant of the Z strain, designated ZR.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bertini F., Brandes D., Buetow D. E. Increased acid hydrolase activity during carbon starvation in Euglena gracilis. Biochim Biophys Acta. 1965 Aug 24;107(1):171–173. doi: 10.1016/0304-4165(65)90414-9. [DOI] [PubMed] [Google Scholar]
- Calvayrac R., Bomsel J. L., Laval-Martin D. Analysis and Characterization of 3-(3,4-Dichlorophenyl)-1,1-Dimethylurea (DCMU)-resistant Euglena: I. Growth, Metabolic and Ultrastructural Modifications during Adaptation to Different Doses of DCMU. Plant Physiol. 1979 May;63(5):857–865. doi: 10.1104/pp.63.5.857. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dubertret G., Joliot P. Structure and organization of system II photosynthetic units during the greening of a dark-grown Chlorella mutant. Biochim Biophys Acta. 1974 Sep 20;357(3):399–411. doi: 10.1016/0005-2728(74)90030-9. [DOI] [PubMed] [Google Scholar]
- Dubertret G., Lefort-Tran M. Functional and structural organization of chlorophyll in the developing photosynthetic membranes of Euglena gracilis Z. II. Formation of system II photosynthetic units during greening under optimal light intensity. Biochim Biophys Acta. 1978 Aug 8;503(2):316–332. doi: 10.1016/0005-2728(78)90191-3. [DOI] [PubMed] [Google Scholar]
- Forbush B., Kok B. Reaction between primary and secondary electron acceptors of photosystem II of photosynthesis. Biochim Biophys Acta. 1968 Aug 20;162(2):243–253. doi: 10.1016/0005-2728(68)90106-0. [DOI] [PubMed] [Google Scholar]
- Garab G. I., Chernisheva S., Kiss J. G., Faludi-Dániel A. Chlorophyll forms affected by 3(3,4-dichlorophenyl)-1,1-dimethylurea as shown by low temperature fluorescence spectra of chloroplasts and fragments. FEBS Lett. 1976 Jan 15;61(2):140–143. doi: 10.1016/0014-5793(76)81021-6. [DOI] [PubMed] [Google Scholar]
- JOLIOT A., JOLIOT P. ETUDE CIN'ETIQUE DE LA R'EACTION PHOTOCHIMIQUE LIB'ERANT L'OXYG'ENE AU COURS DE LA PHOTOSYNTH'ESE. C R Hebd Seances Acad Sci. 1964 May 4;258:4622–4625. [PubMed] [Google Scholar]
- Richard F., Nigon V. La syntheèse de l'acide delta-aminolévulinique et de la chlorophylle lors de l'éclairement d'Euglena gracilis étiolées. Biochim Biophys Acta. 1973 Jun 20;313(1):130–149. [PubMed] [Google Scholar]