ISSN:
1573-5079
Keywords:
ATP level
;
autotrophic/heterotrophic cells
;
plastocyanin formation
;
role of light
;
35S-sulfolipid
;
thylakoid formation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Scenedesmus acutus, pregrown autotrophically, forms high levels of plastocyanin during an initiation period of 24 hr in the light, after cupric ions have been added to depleted cells. In the dark, no plastocyanin formation is observed. This is in contrast to heterotrophic cells which, over the same period and under identical conditions, yield about half the plastocyanin level regardless of whether they are incubated in the dark or in the light. The ATP level is high in all cases when substantial formation of plastocyanin takes place, while the 35S-sulfolipid level, the marker of thylakoid formation, is at variance. After the 24-hr plastocyanin formation period, the 35S-sulfolipid level is high in illuminated autotrophic cells as well as in dark-incubated heterotrophic ones, but low in illuminated heterotrophic cells, all of them having substantial plastocyanin contents. Additional experiments on light dependence of copper uptake, influence of light quality, occurrence of apoplastocyanins, provide a set of data to assume that the role of light in plastocyanin formation is primarily through photophosphorylation, the ATP presumably being necessary for processing of plastocyanin precursors to holoprotein.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00056265
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