Lipids of Chlamydomonas reinhardi under different growth conditions

Photo-, mixo- and heterotrophically grown cultures of Chlamydomonas reinhardi (wild type ss and 2 streptomycin-resistant mutants sr₃ and sr₃₅) have been analyzed for lipids and fatty acids. Ether-soluble lipids, chlorophyll, monogalactosyl diglyceride, digalactosyl diglyceride, sulfolipid, phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol and the relative amounts of fatty acids in total and individual lipids have been determined. The lipid and fatty acid compositions are very similar in the 3 strains and are not affected by the mutations. Fatty acids belong exclusively to the C₁₆ and C₁₈ series, 16:0, 16:4, 18:1, 18:2, 18:3 (6,9,12) and 18:3 (9,12,15) comprising about 90% of the total. 18:3 (6,9,12) is concentrated in phosphatidyl ethanolamine. In streptomycin-bleached sr₃ cells, ether-soluble lipids increase from 7 to 11% of dry weight on greening, mostly due to synthesis of monogalactosyl diglyceride and chlorophyll. Monogalactosyl diglyceride of bleached cells exhibits the same fatty acid pattern before and after greening.     

Differences in Lipid Composition between Undifferentiated and Mature Maize Chloroplasts

Lipid compositions of undifferentiated maize (Zea mays) chloroplasts, capable of fixing CO₂, were compared with the lipid compositions of mature chloroplasts, which do not fix CO₂, located in both the mesophyll and bundle sheath cells. The major lipids found in all three chloroplast types were the glycolipids, monogalactosyl diglyceride and digalactosyl diglyceride, followed by decreasing amounts of sulfolipid, phosphatidyl glycerol, phosphatidyl choline, phosphatidyl inositol, and diphosphatidyl glycerol. Quantitative differences in lipid components were observed among the chloroplast types. The mesophyll and bundle sheath maize chloroplasts differed in their chlorophyll a/chlorophyll b ratios (2.27 and 4.13 respectively) and their content of glycolipid relative to chlorophyll (51.8% glycolipid to 20.9% chlorophyll and 84.5% glycolipid to 10.1% chlorophyll respectively). A comparison between the lipid compositions of maize mesophyll chloroplasts and mesophyll chloroplasts obtained from spinach, sugar beet, and tobacco showed many similarities.     

The Polyunsaturated Fatty Acids of Marine and Freshwater Cryptomonads1

SYNOPSIS Fatty acids were examined of photosynthetic and non-photosynthetic marine and freshwater cryptomonads cultured as photoauxotrophs, photoheterotrophs and heterotrophs at various incubation temperatures and constant light intensity. Photo-synthetic marine and freshwater forms contained octadecatrienoic, octadecatetraenoic, eicosapentaenoic and docosahexaenoic (all-cis, ω3 acids) as the major polyunsaturates, and a freshwater heterotroph contained mostly the octadecatrienoic acid. The polar lipids of a marine, photosynthetic form, Cryptomonas sp., included the usual thylakoid membrane lipids of the chloroplasts of eukaryotic, photosynthetic cells: galactosyl diglycerides, phosphatidyl glycerol and a sulfolipid. Also present were 2 choline-containing phospholipids: phosphatidyl choline and an unknown. Ninhydrin-positive and inositol-containing lipids were not detected. Octadecatetraenoic acid comprised 75% of the total fatty acids of the monogalactosyl diglyceride fraction. The phosphatidyl glycerol was acylated mostly by ω13 trans-hexadecaenoic acid and the eicosapentaenoic acid. Evolutionary relationships of cryptomonads as mirrored in lipid composition are discussed.     

Lipids of ripening tomato fruit and its mitochondrial fraction

The lipid composition of tomato fruit and its mitochondrial fraction were examined at various stages of fruit ripeness. Phosphatidyl choline, phosphatidyl ethanolamine, monogalactosyl diglyceride, digalactosyl diglyceride and phosphatidyl inositol were found to be the major lipids of tomato pericarp at all stages of ripeness. Mitochondrial lipids resembled those of the parent tissue except for the absence of monogalactosyl diglyceride and a greater percentage of diphosphatidyl glycerol and phosphatidic acid. Changes in the lipid-protein ratio of mitochondria were noted with ripening.     

Lipid composition of chloroplasts isolated by aqueous and nonaqueous techniques

Chloroplasts isolated from tobacco leaves in 0.5 M sucrose solution (the 1000 g pellet) contained 83% of the total cellular monogalactosyl diglyceride, 88% of the digalactosyl diglyceride, 76% of the sulfolipid, and 74% of the phosphatidyl glycerol. Phosphatidyl inositol was concentrated in the 15,000 g pellet. Phosphatidyl choline and phosphatidyl ethanolamine were concentrated in the 15,000 g supernatant fraction. Chloroplasts isolated from tobacco leaves by a nonaqueous technique in hexane-carbon tetrachloride show a glycerolipid composition similar to that found in chloroplasts isolated in the aqueous system, even though some lipid, particularly monogalactosyl diglyceride, is extracted by the organic solvent during the process.     

Fatty acid composition of glycerolipids from potato leaves

A method for rapid isolation of glyco- and phospholipids from potato leaves by a two-fold separation in a thin layer of silica gel is described. Using gas-liquid chromatography, the fatty acid compositions of monogalactosyldiglyceride, digalactosyldiglyceride, sulfolipid, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, diphosphatidyl glycerol, phosphatidic acid and non-identified lipid from potato leaves were determined. The monogalactosyl diglyceride was found to contain up to 25% of 7,10,13-hexadecatrienic acid. Trans-3-hexadecenic acid as well as phosphatidyl glycerol is a constituent component of phosphatidic acid, diphosphatidyl glycerol and the non-identified lipid.     

Combination and positional distribution of fatty acids in lipids from blue-green algae

The main glycerolipids (monogalactosyl-, digalactosyl-, sulphoquinovosyl diacylglycerol, phosphatidylglycerol) from five blue-green algae (Microcystis, Anabaena, Nostoc, Oscillatoria, Tolypothrix) were analyzed for fatty acid composition, occurrence of diglyceride species and positional distribution of fatty acids between thesn-1- andsn-2-position of glycerol. In contrast to eucaryotic plants biosynthetically closely related lipids (monogalactosyl-, digalactosyl-, trigalactosyl diacylglycerol) show nearly identical diglyceride moieties, whereas sulphoquinovosyl diacylglycerol and phosphatidylglycerol are separated from galactolipids by composition as well as occurrence of fatty acids. On the other hand the positional distribution of fatty acids in all lipids is controlled exclusively by chain length and not by degree of unsaturation with C₁₈-fatty acids at thesn-1- and C₁₆-fatty acids at thesn-2-position. These results show that in procaryotic organisms the diversity in diglyceride portions of lipids is reduced as compared to eucaryotic organisms, but nevertheless does exist.Abbreviations MGD, DGD, TGD, SQD monogalactosyl-, digalactosyl-, trigalactosyl-, sulphoquinovosyl diacylglycerol - PG phosphatidyl glycerol     

Lipids from Sugar Beet in Relation to the Preparation and Properties of (Sodium + Potassium)-Activated Adenosine Triphosphatases

Field grown leaves of sugar beet contained 0.89% of their fresh weight as chloroform : methanol 1 :2 extractable material, whereas climate chamber grown material contained 0.34, 0.15, and 0.16% in leaves, stalks, and roots respectively. A striking feature was the high proportion of sulfolipid: 7% of the total extractable of the field grown leaves, 19.5, 28.0, and 37.0% of the total extractable of respectively leaves, stalks, and roots from the climate chamber grown material. Among the fatty acids, all chain lengths from C₁₂ to C₂₈ were found, except only C₁₇ and C₁₉—Exceptionally high contents of fatty acids with a chain length of C₂₆ or C₂₈ were noted in some cases. The 2500–20,000 g fraction of root homogenates contained 19% of the total root lipids. Almost all of the phosphatidyl choline and about half of the phosphatidyl ethanolamine, but only 5% of the sulfolipid followed the fraction. A fractionation of conjugate lipid types was evident, with a loss of 18/2 and 18/3 conjugates, and with an increase in the proportions of 16/0 and, possibly, of the long-chain (around C₂₆) conjugates. The unspecific ATPase activity of the 2500–20,000 g fraction was rendered specific for (Na⁺+ K⁺) stimulation by treatment with 0.1% deoxycholate for 1 hour. This induced a more than 2-fold swelling of the preparation. About half of its total lipids were lost. Again, this loss was a fractional one, so that the phosphatidyl choline lost its long-chain (about C₂₆) fatty acid conjugate while the short to medium length chain conjugates remained; whereas the reverse was the case with the sulfolipid. The ATPase activity of the 2500–20,000 g fraction was destroyed by a 24 hour treatment with deoxycholate. As compared with the 1 hour treatment, the preparation lost about 20% both of its volume and of its chloroform : methanol extractable material. The quantitatively dominating loss was found in the (pigment + neutral fat) fraction. The monogalactosyl diglyceride, the phosphatidyl inositol, and a strongly acidic unknown fraction survived the deoxycholate treatments comparatively well. In the sulfolipid the fractionating effect of the prolonged deoxycholate treatment expressed itself as a loss mainly from the long-chain (about C₂₆) fatty acid conjugate. The (Na⁺+ K⁺) stimulation of the ATPase function of the particulate preparation is thus correlated with the balance between the long-chain (about C₂₆) fatty acid conjugates of zwitterionic phosphatidyl choline and anionic sulfolipid. This is of theoretical interest, since it indicates that the specific lipid composition under appropriate conditions may influence the charge and conformation of a lipoprotein complex, thereby determining its functional capacities.     

Fatty Acid Distribution in Glycolipids and Phospholipids in Cotyledons of Germinating Soybeans

This investigation was conducted to observe changes in the fatty acid distributions of glycolipids (GL) and phospholipids (PL) in cotyledons of soybean seeds which were germinated either in the dark or the light at 28°C for 8 days. The GL isolated from the total lipids of cotyledons at different germinating stages were : acyl sterylglycoside (ASG), monogalactosyl diglyceride (MGD), digalactosyl diglyceride (DGD) and sulfolipid (SL). The PL isolated from the same total lipids as described above were : diphosphatidyl glycerol (DPG), phosphatidic acid (PA), phosphatidyl ethanolamine (PE), phosphatidyl glycerol (PG), phosphatidyl choline (PC) and phosphatidyl inositol (PI).

During germination of soybean seeds, the content of linoleic and linolenic acids in MGD or DGD was markedly higher than that of the other GL. The positional distribution of fatty acids in PE, PC and PI was shown in all PL, in which saturated fatty acids, especially palmitic acid, were highly concentrated in position 1 and unsaturated fatty acids, especially linoleic acid, mainly occupied position 2. A remarkable difference in the changing patterns of fatty acid composition, which depended on the germinating conditions tested, was observed between GL and PL. The changes in fatty acid composition of GL were more marked in the light-grown seedlings than in the dark-grown, whereas those of PL were more remarkable in the latter than in the former. Therefore, the positional distribution of fatty acids in PL was more evident in the light-grown seedlings than in the dark-grown ones.

These results suggest the metabolic fate of GL and PL in cotyledons of soybean seeds, probably owing to the differences in the two germinating conditions tested.     

Total polar lipid biosynthesis during growth of Crotalaria juncea pollen tubes

[1-¹⁴C]-Acetate incorporation into total and polar lipids was studied in the growing pollen tubes of Crotalaria juncea. Ungerminated pollen had phosphatidyl inositol, phosphatidyl serine, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, monogalactosyl diglyceride, digalactosyl diglyceride, sulpholipid and steryl glycosides. In the growing pollen tubes considerable [1-¹⁴C]-acetate incorporation was observed into the individual polar lipids. The exogenous carbon source significantly influenced lipid biosynthesis. Boric acid (20mg/l.) promoted both pollen tube growth and acetate incorporation into phospholipids. In comparison to 5′-adenosine monophosphate, cyclic-3′,5′-adenosine monophosphate (cAMP) promoted tube growth and also enhanced phospho-and glycolipid biosynthesis. The regulation of membrane component biosynthesis by cAMP is suggested.     

Lipids in alfalfa leaves in relation to cold hardiness

The lipid composition of the leaves of hardy Vernal and cold-sensitive Caliverde alfalfa plants, grown at different temperatures, was determined. Phosphatidyl glycerol, phosphatidyl inositol, and the sulfolipid content were directly related to growth temperature. Mono- and digalactose diglyceride and phosphatidyl choline and ethanolamine were inversely related to temperature. At corresponding growth temperatures Vernal plants showed higher percentages of mono- and digalactose diglyceride and phosphatidyl choline and ethanolamine than Caliverde plants, while the opposite was true for phosphatidyl glycerol and inositol and sulfolipid. Differences in fatty acid composition of corresponding leaf lipid fractions of plants grown at different temperatures or differences in fatty acid composition between lipid fractions of plants of different varieties in general were negligible.     

Lipid and Fatty-acid Composition of Diatoms

The lipids and fatty acids of two freshwater diatoms Nitzschiapalea Kutz, Navicula muralis Lewin, and one marine species,Navicula incerta Grun. have been studied. The major lipid components in all species were triglycerides,monogalactosyl, digalactosyl and sulphoquinovosyl diglycerides,phosphatidyl glycerol, phosphatidyl choline (lecithin), andphosphatidyl ethanolamine; while palmitoleic, palmitic, eicosapentaenoicand eicosate-traenoic acids were the major fatty acid constituents.The two galactolipids, monogalactosyl and digalactosyl diglyceridescontained large amounts of C₁₆ and C₂₀ polyunsaturated fattyacids. Lipids of diatoms, whether grown in the light or in the dark,were the same apart from quantitative differences. More storagelipids such as triglycerides were synthesized in the light thanin the dark.     

Complex lipids of Rhodomicrobium vannielii

Eight components, seven of which contained phosphorus, were found in the phospholipid fraction of Rhodomicrobium vannielii. The major components were lipoamino acid (o-ornithine ester of phosphatidyl glycerol, 46.5%) and phosphatidyl choline (26.5%). The other six components were phosphatidyl glycerol (9.7%), bisphosphatidic acid (6.7%), phosphatidyl ethanolamine (4.5%), phosphatidic acid (1.8%), lysophosphatidyl glycerol-o-ornithine ester (3.2%), and N,N-ornithine amide of unidentified fatty acid (0.95%). Total phospholipid accounted for 4.2% of cell dry weight. The major fatty acid was vaccenic acid, C_18:1, which accounted for approximately 90% of the total fatty acids of the complex lipid fraction. The other four fatty acids were C_16:0 (6.25%), C_18:0 (3.8%), C_14:0 (0.7%), and C_16:1 (0.35%). The sulfolipid content was 0.01% of the cell dry weight or 0.14 μmoles per g of dried cells, assuming that its fatty acid component is vaccenic acid. No steroids were detected.     

Changes in Glycolipid and Phospholipid Compositions in Cotyledons of Germinating Soybeans

This investigation was conducted to observe changes in the compositions of fatty acids, glycolipids (GL) and phospholipids (PL) in cotyledons of soybean seeds which were germinated either in the dark or the light at 28°C for 8 days. The patterns of changes in lipid composition depended on the germinating conditions tested. In general, non-polar lipids were metabolized at a faster rate than polar lipids. Changes in lipid contents in cotyledons were also observed more clearly with the polar lipids than with the non-polar ones, especially in the light-grown seedlings. The major component of lipid, GL in chloroplasts, appeared rapidly at an earlier stage in the cotyledons of light-grown seedlings. During germination of soybean seeds, acyl sterylglucoside in cotyledons decreased rapidly, but monogalactosyl diglyceride and digalactosyl diglyceride (DGD) increased in the light-grown seedlings, whereas sterylglucoside and DGD increased in the dark-grown seedlings.

The major PL present immediately after immersion were phosphatidyl ethanolamine (PE), phosphatidyl choline (PC) and phosphatidyl inositol (PI). During germination under both conditions, light and dark, PE in cotyledons decreased with PC or PI, while phosphatidic acid increased rapidly, and phosphatidyl glycerol and diphosphatidyl glycerol also increased slightly. These changes in glycolipid and phospholipid compositions during germination seem to occur from the formation of photosynthetic tissues and the metabolic interconversion of phospholipids.     

Role of Galactolipids in Spinach Chloroplast Lamellar Membranes: II. Effects of Galactolipid Depletion on Phosphorylation and Electron Flow

A galactolipid lipase from primary bean (Phaseolus vulgaris) leaves has been used to partially deplete spinach chloroplast inner membranes of their galactolipids. Chloroplasts treated with the lipase in the absence of bovine serum albumin lost 91% of their monogalactosyl diglyceride, 83% of their digalactosyl diglyceride, all of their phosphatidyl choline, but none of their sulfolipid. Electron microscopy of this sections revealed that the treated chloroplasts were greatly enlarged and lacked membrane stacking. Linolenic acid had similar effects on the structure of the chloroplasts. Chlorophyll, carotenoids, and coupling factor 1 remained bound to the treated membranes.     

Changes in Chloroplast Lipids during the Development of Photosynthetic Activity in Barley Etio-Chloroplasts

The content of monogalactosyl diglyceride, digalactosyl diglyceride, sulfoquinovosyl diglyceride and phosphatidyl glycerol of gel-filtrated etio-chloroplasts isolated from greening barley seedlings was determined. The development of photosynthetic electron transport, measured as anthraquinone autooxidation, was simultaneously determined with an oxygen electrode. During the first hour of irradiation of the etiolated seedlings the lipid content of the plastids decreased rapidly. The decrease is interpreted as a chlorophyll sensitized photooxidation of the fatty acids of the diglycerides. With artificial electron donors an oxygen uptake was detected after 10 min of greening. With no donors added, a DCMU sensitive oxygen uptake was detected after 2 h. The level of DCMU inhibition increased as the plastid developed and total inhibition was obtained after 5 h. Between 2 and 6 h of greening the lipid content of the plastids stayed constant. During this greening period there was a correlation between the appearance of a DCMU sensitive electron transport and the accumulation of the trans-3-hexadecenoic acid of phosphatidyl glycerol. The trans-3-hexadecenoic acid was present already in the dark-grown seedlings but an increase in content did not occur until after 3 h. The lipid content increased after 6 h of greening. This increase coincided well in time with the formation of grana. The fatty acid composition of the individual lipids, with the exception of phosphatidyl glycerol, and the monogalactosyl diglyceride to digalactosyl diglyceride ratios did not change fundamentally during the greening.     

Age dependent changes in phospholipids and galactolipids in primary bean leaves (Phaseolus vulgaris)

Primary leaves of Phaseolus vulgaris show concomitant changes in phospholipid, galactolipid, chlorophyll and fresh weight during leaf development from 3 to 32 days after planting. Phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl inositol show only small changes on a mole per cent lipid phosphate basis during leaf development. The chloroplast lipids, phosphatidyl glycerol, monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) all show marked increases and decreases which are coincident with chloroplast development. The decline in the leaf content of chloroplast polar lipids and chlorophyll become evident upon reaching maximal leaf size. The molar ratio of galactolipids (MGDG/DGDG), reaches a maximum value of 2.3 in expanding leaves, but steadily declines during senescence to a minimum value of 1.5 at abscission. The declining ratio is caused by a preferential loss of MGDG in the senescing leaves.     

Lipid Composition of Some Species of Arthrobacter

The lipids from Arthrobacter crystallopoietes, A. pascens, and A. globiformis were investigated. Each strain contained three glycolipids, a monogalactosyl diglyceride, a digalactosyl diglyceride, and a dimannosyl diglyceride, and traces of triand tetraglycosyl diglycerides. The phospholipids in all three strains consisted of bisphosphatidylglycerol, phosphatidylglycerol, and phosphatidylmyoinositol. No evidence could be obtained for the occurrence of mannophosphoinositides. Analysis of the fatty acids by gas-liquid chromatography showed that they are predominantly C_15:0anteiso and C_17:0anteiso compounds. No significant differences were observed in the composition of lipids extracted from homogeneous cell preparations of the rod and sphere forms of A. crystallopoietes.     

Isolation and characterization of glycolipids from some photosynthetic bacteria

Glycosyl glycerides have been found in substantial amounts in Chloropseudomonas ethylicum but could not be detected in two strains of Rhodopseudomonas palustris. Rhodospirillum molischianum possibly contains small amounts of monoglycosyl diglyceride. The glycolipids of C. ethylicum have been separated into two components. One of these, glycolipid I, is a monogalactosyl diglyceride. Glycolipid II, upon acid hydrolysis, yields galactose, rhamnose, and a third, unidentified sugar. The glycolipids or total lipids of the photosynthetic bacteria examined contained saturated and monounsaturated, but none of the more highly unsaturated, fatty acids.     

Photo-oxidative Degradation of Chlorophyll-a and Unsaturated Lipids in Liposomal Dispersions at Low-Temperature

Liposomal dispersions in water were used as a tool to study photo-oxidation of chlorophyll-a and photo-oxidation of unsaturated lipids at 1 or 4°C. The presence of monogalactosyl diglyceride stimulated chlorophyll-a degradation. In addition the level of linolenic acid was decreased in liposomal dispersions containing chlorophyll-a, dipalmitoyl phosphatidyl choline, and monogalactosyl diglyceride, indicating that monogalactosyl diglyceride and chlorophyll-a were coupled in the preparations. In liposomal dispersions containing equal (molar) quantities of a-tocopherol, monogalactosyl diglyceride, and chlorophyll-a, a-tocopherol fully protected linolenic acid against photo-oxidative degradation, while chlorophyll-a degradation was only slightly reduced. In liposomal preparations containing a-tocopherol, chlorophyll-a and phosphatidyl choline, a-tocopherol catalyzed degradation of chlorophyll-a. Absorption spectra of the liposomal dispersions showed that the presence of a-tocopherol caused increased absorption in red light, which was attributed to structural changes in the liposomal preparations and thus could explain the noted effects. Tocopherol itself was rapidly degraded in chlorophyll-a containing liposomal preparations. Complex formation between chlorophyll-a and monogalactosyl diglyceride in chloroplasts is suggested and protection by a-tocopherol against photo-oxidation in chilling-sensitive plants; a suggestion which is founded on the similarities that exist between chloroplast preparations and liposomal preparations containing chlorophyll-a and monogalactosyl diglyceride as regards photo-oxidative degradation of chlorophyll-a, a-tocopherol and linolenic acid.