Stabilization by glutaraldehyde of high-rate electron transport in isolated chloroplasts

Hardt, Haim; Kok, Bessel

doi:10.1016/0005-2728(76)90012-8

Cited by 34 publications

(17 citation statements)

References 11 publications

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“…It is well known that a decrease in activity is due to the chemical effect of the glutaraldehyde action (38). However, as already described (17,38) in fixation studies, we observe also a stabilization of cross-linked thylakoids. Figure 1 illustrates the time course of changes of the PSII activity of native and immobilized thylakoids, when they are prepared with or without 0.15 to 1.5 mM Na', during storage at 4VC.…”

Section: Resultssupporting

confidence: 83%

“…As already observed in the case of suspensions (17,18,38), the glutaraldehyde acts not only as a chemical inhibitor of the electron transport activity but also as a stabilizing agent. However, in the present report, the stability observed under storage and functional conditions is increased by the concomitant presence of serum albumin.…”

Section: Discussionsupporting

confidence: 59%

“…The action of glutaraldehyde on the structure and function of chloroplast has been studied extensively (17,18,38) and was reviewed recently by Papageorgiou (30). The glutaraldehyde fixation stabilizes activities but blocks chloroplast reactions at specific sites (17).…”

mentioning

confidence: 99%

“…The glutaraldehyde fixation stabilizes activities but blocks chloroplast reactions at specific sites (17). However, some microconformational changes may still occur after fixation (18,30).…”

mentioning

confidence: 99%

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Immobilized Thylakoids in a Cross-Linked Albumin Matrix

Thomasset¹,

Thomasset²,

Vejux³

et al. 1982

Plant Physiol.

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Immobilization of lettuce (Lactuca sativa) thylakoids has been performed by using glutaraldehyde and bovine serum albumin. Confiming previous reports, a stabilization of the 02 evolution activity of the photosystem II (PSII) under storage and functional conditions has been observed. The present work is devoted to the role played by mono-and divalent cations, during the immobilization process itself, on the 02 productionL Four types of measurements have been employed: kinetic measurements, low temperature (77 K) fluorescence emission, photoacoustic (PA) spectroscopy, and electron microscopy observations. We show that the effect of glutaraldehyde is complex because it acts as an inhibitor, a stabilizing agent, and a cross-linking reactive. In the present studies, the thylakoids are immobilized within a polymeric insoluble albumin matrix. The highest activity yield and the best storage conditions are obtained when 0.15 mM Na' (or K+), 1 mm Mg2+, and 0.1 mM Mn2l are present in the resuspending media before the immobilization. Due to modifications of the ionic content during such a process, structural differences are observed on the stacking degree of thylakoids. No modification of the fluorescence and PA spectra after the immobilization are found. Furthermore, a correlation between activities and spectral changes have been shown: when the activities increase, the F735 to F695 ratio increases and the PA676 to PA4o ratio decreases.In recent years, there has been progress (3,16,23,32) in the research on technological applications of photobiological solar energy conversion (biophotolysis of water, photohydrogen production, and ATP regeneration). However, the life time of the isolated chloroplasts was very short, and the stability of PSI and PSII activities over a long period of time was a crucial limitation for these applications.Recent advances have been made in techniques for immobilization of biocatalysts (27), and chloroplasts isolated from plants were immobilized by several different methods like microencapsulation (22), adsorption (33), entrapment within gels (9,14,21,29), radiation polymerization (13), or cross-linking with glutaraldehyde in the presence of albumin (9,20,23). A functional stabilization of the photosystems activities has been obtained and some of these methods were recently compared (9). In the present paper, we have selected the cross-linking technique to study the effect of mono-and divalent cations on the PSII stability.The action of glutaraldehyde on the structure and function of chloroplast has been studied extensively (17, 18, 38) and was reviewed recently by Papageorgiou (30). The glutaraldehyde fixation stabilizes activities but blocks chloroplast reactions at specific sites (17). However, some microconformational changes may still occur after fixation (18,30). In such studies, the glutaraldehyde treatment does not give insoluble and polymeric structures. In our work, the co-crosslinking method gives thylakoids immobilized within an insoluble albumin matrix. Our aim is to obtain in...

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Section: Resultssupporting

confidence: 83%

Section: Discussionsupporting

confidence: 59%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Immobilized Thylakoids in a Cross-Linked Albumin Matrix

Thomasset¹,

Thomasset²,

Vejux³

et al. 1982

Plant Physiol.

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“…In a preceding paper we described attempts to stabilize the photochemical activity of chloroplasts in vitro (7). We reported that GA2-treated chloroplasts, in which electron transport from water to viologen or ferricyanide (18,21,25) is inhibited, evolve 02 with high rate in the presence of lipophilic electron acceptors (23).…”

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confidence: 99%

Plastocyanin as the Possible Site of Photosynthetic Electron Transport Inhibition by Glutaraldehyde

Hardt¹,

Kok²

1977

Plant Physiol.

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Treatment of spinach chloropbdats with glutaraldebyde causes an inhibition in the electron transport chain between the two photosystems. Measurements of 02 flash yields, pH exchange, and fluorescence induction show that the 02 evolving apparatus, photosystem n and its electron acceptor pool are not affected. The behavior of P700 indicates that its reduction but not its oxidation, is severely inhibited. Cytochromef is stiDl reducible by photosystem H but also slowly oxidizable by photosystem I.The sensitivity of isolated plastocyanin to glutaraldehyde further supports the condusion that glutaraidehyde inhibits at the plastocyanin level and thereby induces a break between P700 and cytochromef.In a preceding paper we described attempts to stabilize the photochemical activity of chloroplasts in vitro (7). We reported that GA2-treated chloroplasts, in which electron transport from water to viologen or ferricyanide (18,21,25) is inhibited, evolve 02 with high rate in the presence of lipophilic electron acceptors (23).A similar discrimination between the two types of electron acceptors has been observed in chloroplasts which were inhibited by KCN (20), DBMIB (8), or polycations (3, 19). These various agents appear to affect electron transport between the two photosystems so that the reduction of hydrophylic acceptors, which are presumably reduced by PSI, is inhibited. The reduction of lipophylic acceptors is unimpaired, presumably because they are reduced by PSII directly, possibly via plastoquinone. We have assumed that GA causes a similar inhibition and this paper presents additional attempts to locate the site of inhibition. MATERIALS AND METHODSSpinach chloroplasts fixed by GA and reaction mixtures for assaying electron transport activities were prepared as described in our preceding paper (7).Techniques used for the various measurements, such as flash yields of 02 or pH, fluorescence induction, and absorption changes have been described earlier (4,5,13,17). Routinely, the chloroplasts used in the present study were fixed by a 5-min

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Fluorescence and photoacoustic spectroscopy of immobilized thylakoids

Thomasset

Barbotin

Thomas

et al. 1983

Biotech & Bioengineering

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The O(2) evolution activity of immobilized chloroplast membranes in different environments (albumin-glutaraldehyde matrix, urethane polymer and alginate beads) is presented. As previously shown, the stability of photosystem II (PS II) of lettuce thylakoids appears to be increased by the immobilization process. For understanding such stability, some spectral investigations have been made about the energy distribution between the immobilized photosystems. The low-temperature (77 K) fluorescence emission and photoacoustic spectroscopy are well adapted to solid particle studies. Especially, it has been shown that the fluorescence ratio (F(735)/F(695)) and photoacoustic ratio (PA(676)/PA(440)) are good indicators of the functional level of native and immobilized thylakoids. Such ratios are also given after storage and after continuous illumination conditions. Some results about the role played by glutaraldehyde (in the case of albumin-glutar-aldehyde matrix) in the stabilization process are also reported.

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Stabilization by glutaraldehyde of high-rate electron transport in isolated chloroplasts

Cited by 34 publications

References 11 publications

Immobilized Thylakoids in a Cross-Linked Albumin Matrix

Immobilized Thylakoids in a Cross-Linked Albumin Matrix

Plastocyanin as the Possible Site of Photosynthetic Electron Transport Inhibition by Glutaraldehyde

Fluorescence and photoacoustic spectroscopy of immobilized thylakoids

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