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...

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.

As a contribution to the scientific knowledge of the Turin Shroud, we have studied by SEM-EDX a small hair fragment (14 × 9 μ) contained in a blood stain located in the Face between the two eyebrows. SEM study of this fragment shows the typical human scale hair pattern. EDX analysis of the fragment indicates that it is mainly made of organic matter, plus a little sulphur peak. The hair fragment was at both cut extremities with a razor blade formed of copper. Comparisons with present hairs of different sorts show that the hair fragment is a shaven down-hair. High-resolution SEM analysis of the pattern of residual melanosomes on the hair surface explains the blond-red colour of this hair observed in optical microscopy.

As our new contribution to the scientific knowledge of Holy Maria-Magdalena remains, we have studied pollens and several vegetal tissues of fennel adhering to her hairs by optical microscopy and SEM-EDX. Pollen grains, foliar, pedicelar and stem debris found are characteristics of Foeniculum vulgare. Detailed examination of these tissue debris shows that the plant involved was carefully processed and cultivated. Fennel symbolism is an important attribute to the Marie-Madeleine worship concerning the French "Tradition des Saints de Provence".

As a new contribution to the scientific knowledge of Holy Maria-Magdalena's remains, we have studied by SEM-EDX some mineral particles and microorganism debris adhering to her hair. We found on it mineral particles of gypsum, aragonite and salt, algae fragments, microorganism as diatoms, coccoliths and tintinnides, and micro-debris of Crustaceans. Such marine micro-remains indicate a past close contact of the hair with sea water.