Circadian Rhythms

Sweeney, Beatrice M.; Prézelin, Barbara B.

doi:10.1111/j.1751-1097.1978.tb07684.x

Cited by 19 publications

(2 citation statements)

References 69 publications

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“…Changes of metabolic activity during day and night are well documented (Sweeney and Prezelin, 1978;Prezelin and Ley, 1980). Changes in algal sensitivity to Zn and Cd might parallel changes in culture conditions.…”

Section: Introductionmentioning

confidence: 99%

Influence of low cadmium and zinc concentrations on batch culture Prorocentrum micans (Dinophyta) containing low levels of dissolved organic carbon

Rabsch¹,

Wolter²,

Krischker³

1984

Mar. Ecol. Prog. Ser.

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Experiments with Prorocentrum micans Ehrenberg were run over a period of 380 h in North Sea water containing 0.5 mg C 1-' of dissolved organic carbon. Dissolved Cd concentrations ranged from 0.08 to 10 pg l-'; Zn concentration was 0.1 pg 1-'. Cell density started with 35 000 1-'. Growth in terms of cell numbers, primary productivity, bacterial activity, and uptake of Zn and Cdmeasured by the radlo isotopes 6 5~n and ' OgCd -were followed in short intervals during exponential and stationary growth phases. Enrichment factors of the metals were highest at the lowest Cd concentration. On a daily basis, Cd and Zn concentrations increased during the day and decreased at night. The rhythm was most obvious during exponential growth. This indicates the special role of actively metabolising cells for uptake of Zn and Cd. Accumulation was more rapid for Zn (maxima every 24 h) than for Cd (maxima every 26 h), so that the daily rhythm of the metals was shifted.

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Section: Introductionmentioning

confidence: 99%

Influence of low cadmium and zinc concentrations on batch culture Prorocentrum micans (Dinophyta) containing low levels of dissolved organic carbon

Rabsch¹,

Wolter²,

Krischker³

1984

Mar. Ecol. Prog. Ser.

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“…Evidence that membranes might be components of circadian oscillators arises from different sources [5,37]. However, there is no report on the direct involvement of membrane protein synthesis in the mechanism of circadian rhythm.…”

Section: Amino-terminal Analysismentioning

confidence: 99%

The Role of Chloroplast‐Membrane‐Protein Synthesis in the Circadian Clock

Leong

Schweiger

1979

European Journal of Biochemistry

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A polypeptide (polypeptide P39), which is presumed to be involved in the photosynthetic circadian rhythm in the green alga Acetabularia, was purified from the EDTA-insoluble chloroplast membrane fraction by means of preparative dodecylsulfate gel electrophoresis and then partially characterized.The purity of the isolated polypeptide P39 was confirmed by a further electrophoresis on an analytical dodecylsulfate gel and further elucidated by amino-terminal analysis which shows that glycine is the only amino-terminal amino acid of the purified polypeptide material. The molecular weight of the polypeptide P39 was found to be about 39000 on analytical gel electrophoresis and the value was further supported by those obtained from amino acid composition and peptide mapping.The amino acid composition of polypeptide P39 showed that the proportion of intermediate amino acid groups is high while the proportion of hydrophilic amino acid groups is well balanced by that of hydrophobic amino acid groups, a property characteristic of membrane proteins.Cycloheximide is known to cause phase shifts in the photosynthetic circadian rhythm of Acetabulavia in a phase and temperature-dependent manner [l]. Previous reports [2-41 indicate that at least one protein (polypeptide P39, designated as polypeptide X in [3,4]) is synthesized in the presence of cycloheximide and is retained within the chloroplast membrane fraction. The time and amount of the synthesis of polypeptide P39 in the presence of cycloheximide coincide with the time and duration, respectively, of sensitivity towards cycloheximide for phase-shifting the photosynthetic circadian rhythm. This polypeptide (polypeptide P39) was suggested to play an essential role in the circadian clock [4,5]. It was, therefore, tempting to purify this polypeptide and to study its characteristics and biochemical properties in order to further understand the regulating mechanism underlying the photosynthetic circadian rhythm.Although much is known about the structure, function and bioenergetics of the chloroplast [6 -141, only a few protein components have been isolated from the chloroplast membrane and characterized [15 -221. Most of these are chlorophyll-protein functional complexes related to the photosystems I and 11.

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Oscillations in Wheat Chloroplast Photochemical Activity: Effect of Uncouplers

Sayeed

Mohanty

1987

Membrane Receptors, Dynamics, and Energetics

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Circadian Rhythms

Cited by 19 publications

References 69 publications

Influence of low cadmium and zinc concentrations on batch culture Prorocentrum micans (Dinophyta) containing low levels of dissolved organic carbon

Influence of low cadmium and zinc concentrations on batch culture Prorocentrum micans (Dinophyta) containing low levels of dissolved organic carbon

The Role of Chloroplast‐Membrane‐Protein Synthesis in the Circadian Clock

Oscillations in Wheat Chloroplast Photochemical Activity: Effect of Uncouplers

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