Biology

In the book viewed and analysed  results of investigation of plant
sulfur containing lipids. Their functions in normal environment and
role in adaptative reaction. They  have been found almost in all
photosynthetic plants, algae, photosynthetic Protozoa, bacteria. and
appear to be concentrated mainly in the photosynthesising membranes.
The purple membrane of certain  archaebacteria contains protein
bacteriorhodopsin and 10 haloarcheal lipids per protein unit including
phosphatidylglycerol sulfate and a sulfated triglycoside lipid located
in the central compartment of the bacteriorhodopsin trimer.
Sulphoquinovosyl diacylglycerol  is associated with purified
chloroplast CF0-CF1 ATP-ase and supposed does not form lipid matrix
or is involved in ‘protein packing’ like galactolipids but plays a more
specific role in the catalytic activity of proteins. Results recent works
showed that for the stable activity PSII needs the presence of
sulphoquinovosyl diacylglycerol and that it participates in PSII
recovering through some mechanism dependent on light. The results
of studies devoted to lipid involvement in adaptation processes show
that sulphoquinovosyl diacylglycerol quantitative changes and acyl
composition shifts take place at abiotic and biotic factors impact.

In the book viewed and analysed  results of investigation of plant
sulfur containing lipids. Their functions in normal environment and
role in adaptative reaction. They  have been found almost in all
photosynthetic plants, algae, photosynthetic Protozoa, bacteria. and
appear to be concentrated mainly in the photosynthesising membranes.
The purple membrane of certain  archaebacteria contains protein
bacteriorhodopsin and 10 haloarcheal lipids per protein unit including
phosphatidylglycerol sulfate and a sulfated triglycoside lipid located
in the central compartment of the bacteriorhodopsin trimer.
Sulphoquinovosyl diacylglycerol  is associated with purified
chloroplast CF0-CF1 ATP-ase and supposed does not form lipid matrix
or is involved in ‘protein packing’ like galactolipids but plays a more
specific role in the catalytic activity of proteins. Results recent works
showed that for the stable activity PSII needs the presence of
sulphoquinovosyl diacylglycerol and that it participates in PSII
recovering through some mechanism dependent on light. The results
of studies devoted to lipid involvement in adaptation processes show
that sulphoquinovosyl diacylglycerol quantitative changes and acyl
composition shifts take place at abiotic and biotic factors impact.

The plant sulfolipid, sulfoquinovosyldiacylglycerol (SQDG), is a major component of chloroplast thylakoid membranes found in all photosynthetic plants, algae, protozoa, lichen and bacteria. It is synthesised mainly in the inner envelope membrane. The formation of C-S seems to begin at the C6-level with UDP-glucose or UDP-galactose acting as precursors. During ageing SQDG is degraded to inorganic sulfate which is then reutilized. SQDG is associated with purified chloroplast CF 0 -CF 1 ATPase, the LHC II-apoproteins, and native D1/D2 heterodimer. SQDG changed in quantity and quality during low and high temperature, drought, salinity stress, CO 2 stress and infection, indicating a function in stress reactions.

The results of studies devoted to lipid involvement in adaptation processes show that just galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are among the most susceptible polar lipids. MGDG and DGDG occur in all higher plants and are the predominant lipid components of chloroplast membranes. The third glycolipid is sulfolipid sulfoquinovosyl diacylglycerol (SQDG) with a sulfonic acid derivative of glucose. They are thought to be of major importance to chloroplast morphology and physiology, although direct experimental evidence is still lacking. . The glycerolipid DGDG is exclusively associated with photosynthetic membranes and thus may play a role in the proper assembly and maintenance of the photosynthetic apparatus . Bearing in mind that oxidative stress is a component part of the reaction of plants to many other stresses, any changes in lipid composition are of special significance. Data available evidence that oxidative processes induced by high concentration of ozone affect glycolipid composition. observed marked decreases in these galactolipids, which started within 2 hours of the onset of ozone exposure. Loss of MGDG was more rapid than that of DGDG, resulting in a significant reduction of MGDG/DGDG ratio in spinach and snapbean ) at least. T.Sakaki considers the first phase of the injury development to continue for the initial 8 h of exposure. A little loss of pigments and lipids (MGDG significantly and DGDG slightly) accompanied by slight increase of MDA content take place while this period. However, marked oxidation of ascorbate and inactivation superoxidismutase (SOD) and ascorbate peroxidase (AP) have already occurred during this period. The second phase characterised by massive destruction of pigments and lipids starts with drastic fall of MGDG and less sharp decrease of DGDG accompanied by significant increase of TG, 1,2-DG and MDA . But it is interesting that anionic lipid -SQDG and PI -amounts were stable while the time of exposure (in spinach leaves, at least). Lipid changes similar to those in spinach were also observed in several plant species, and in broad bean leaves the SQDG increase took place. Oxidative stress induced fall of both GL (MGDG especially drastic) content while SQDG l evel was stable in a number of plants. As a result SQDG content relative to glycolipid quantity increased by 7-45% (depending upon species) . But results obtained by with garden pea evidence that moderately enhanced ozone level caused large decreases not only in the contents of MGDG and DGDG, but in SQDG also. Compared with charcoalfiltered air, fumigation with ozone resulted in decreased 18:3 and increased 18:2 in MGDG and SQDG, while the fatty acid composition of DGDG was unaffected. Concerning the molecular bases of these structural changes suggested that the primary reaction of ozone is the stimulation of galactolipase activity resulting in the enhanced production of free fatty acid in chloroplasts. It is considered that an increase in galactolipase activity is a general feature in response to ozone. demonstrated that ozone stimulated degradation of galactolipids in garden pea leaves probably by galactolipase without effects on the de nova lipid synthesis. Besides, it is well-known that galactolipids as unsaturated compounds are good substrate for forming peroxidation products observed at ozone action . Therefore it seems to be worthwhile to explore various tension