P. Grattan Roughan
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Stromal concentrations of coenzyme A and its esters are insufficient to account for rates of chloroplast fatty acid synthesis: evidence for substrate channelling within the chloroplast fatty acid synthase Open
Concentrations of total CoAs in chloroplasts freshly isolated from spinach and peas were 10–20 μM, assuming a stromal volume of 66 μl per mg of chlorophyll. Acetyl-CoA and CoASH constituted at least 90% of the total CoA in freshly isolated…
Evidence That Isolated Chloroplasts Contain an Integrated Lipid-Synthesizing Assembly That Channels Acetate into Long-Chain Fatty Acids Open
High rates of light-dependent fatty acid synthesis from acetate were measured in isolated chloroplasts that were permeabilized to varying extents by resuspension in hypotonic reaction medium. The reactions in hypotonic medium unsupplemente…
Fatty Acid Specificity and Selectivity of the Chloroplast <i>sn</i>-Glycerol 3-Phosphate Acyltransferase of the Chilling Sensitive Plant, <i>Amaranthus lividus</i> Open
Chilling sensitivity of plants is strongly correlated with the presence of high levels of a species of chloroplast phosphatidylglycerol that contains two saturated fatty acids. The most straightforward synthetic pathway for this lipid woul…
Spinach Leaves Desaturate Exogenous [<sup>14</sup>C]Palmitate to Hexadecatrienoate Open
Long-chain (14)C-fatty acids applied to the surface of expanding spinach leaves were incorporated into all major lipid classes. When applied in diethyleneglycol monomethyl ether solution, as done by previous workers, [(14)C]palmitic acid u…
Phosphatidylglycerol and Chilling Sensitivity in Plants Open
The hypothesis that molecular species of thylakoid phosphatidylglycerol containing two saturated fatty acids (disaturated phosphatidylglycerol) confer chilling sensitivity upon plants was tested by analyzing the fatty acid composition of p…
Glycerolipid labelling kinetics in isolated intact chloroplasts Open
Glycerolipid synthesis was studied in intact chloroplasts isolated from three different plant species. The sequential acylation of sn-glycerol 3-phosphate and lysophosphatidate (1-acyl-sn-glycerol 3-phosphate) was confirmed by monitoring t…
Histology of several cool-season forage grasses digested by cellulase Open
Leaf blade sections (3 cm long) from the last fully collared leaf of plants from genotypes of perennial ryegrass (Lolium (multiflorum Lam. × perenne L.) × perenne L.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.)…
Rates and Products of Long-Chain Fatty Acid Synthesis from [1-<sup>14</sup>C]Acetate in Chloroplasts Isolated from Leaves of 16:3 and 18:3 Plants Open
Chloroplasts highly active in the synthesis of long-chain fatty acids from [1-(14)C]acetate were prepared from leaves of Solanum nodiflorum, Chenopodium quinoa, Carthamus tinctorius, and Pisum sativum. These preparations were used to test …
Similarities and Differences in Lipid Metabolism of Chloroplasts Isolated from 18:3 and 16:3 Plants Open
Photosynthetically active chloroplasts retaining high rates of fatty acid synthesis from [1-(14)C]acetate were purified from leaves of both 16:3 (Solanum nodiflorum, Chenopodium album) and 18:3 plants (Amaranthus lividus, Pisum sativum). A…
Relationship between fatty-acyl composition of diacylgalactosylglycerol and turnover of chloroplast phosphatidate Open
Chloroplasts from plants that contain different proportions of the 2-hexadecatrienoyl-1-linolenoyl molecular species in total diacylgalactosylglycerol were examined for their ability to dephosphorylate phosphatidate that had been labelled …
Manipulating the Incorporation of [1-<sup>14</sup>C]Acetate into Different Leaf Glycerolipids in Several Plant Species Open
During short term labeling of expanding leaves of seven plant species with [1-(14)C]acetate, 35 to 64% of the label incorporated into lipids was found in phosphatidylcholine and 5 to 24% in phosphatidylglycerol. In pumpkin, sunflower, broa…
Effect of BASF 13-338, a Substituted Pyridazinone, on Lipid Metabolism in Leaf Tissue of Spinach, Pea, Linseed, and Wheat Open
A substituted pyridazinone (BASF 13-338) inhibited photosynthesis in spinach (Spinacia oleracea, Hybrid 102 Arthur Yates Ltd.) leaf discs and reduced the incorporation of [1-(14)C]acetate into trienoic acids of diacylgalactosylglycerol whi…
Effects of Cyanide on Rates and Products of Fatty Acid Synthesis by Chloroplasts Isolated from <i>Spinacia oleracea</i> Open
Cyanide inhibited unesterified fatty acid synthesis but stimulated glyceride synthesis from [1-(14)C]acetate when Spinacia oleracea chloroplasts were incubated in basal media. Both unesterified fatty acid and glyceride accumulation were in…
Light control of fatty acid synthesis and diurnal fluctuations of fatty acid composition in leaves Open
1. Although isolated spinach chloroplasts were almost entirely (greater than 99%) dependent on light for fatty acid synthesis, leaf discs were capable of fatty acid synthesis in the dark (up to 500nmol of 3H/h per mg of chlorophyll equival…
Influence of drying method and post-harvest conditions on total nitrogen, soluble sugar, and starch levels in plant tissue Open
Shoot material from several species (Digitaria, Setaria, Phalaris, ryegrass, maize, and white clover) dried by 4 different methods was analysed for total nitrogen, soluble sugar, and starch concentrations. Recoveries of sugars and starch w…
The role of chloroplasts and microsomal fractions in polar-lipid synthesis from [1-14C]acetate by cell-free preparations from spinach (<i>Spinacia oleracea</i>) leaves Open
1. Isolated spinach (Spinacia oleracea) chloroplasts were incapable of accumulating polar lipids when incubated with [1-14C]acetate in a cofactor-free medium. When CoA, ATP and glycerol 3-phosphate were added to incubation media, the accum…
Acetate is the preferred substrate for long-chain fatty acid synthesis in isolated spinach chloroplasts Open
1. Commercially available [2-14C]pyruvate and [2-14C]malonate were found to contain 3-6% (w/w) of [14C]acetate. 2. The contaminating [14C]acetate was efficiently utilized for fatty acid synthesis by isolated chloroplasts, whereas the paren…
Linoleate and α-linolenate synthesis by isolated spinach (<i>Spinacia oleracea</i>) chloroplasts Open
Diacylgalactosylglycerol synthesis was a prerequisite for the incorporation of [1-14C]-acetate into linoleate and alpha-linolenate of isolated spinach (Spinacia oleracea) chloroplasts. Oleate at position 1 of diacylgalactosylglycerol was d…
On the control of long-chain-fatty acid synthesis in isolated intact spinach (<i>Spinacia oleracea</i>) chloroplasts Open
1. Chloroplasts isolated from spinach leaves by using the low-ionic-strength buffers of Nakatani & Barber [(1977) Biochim. Biophys. Acta.461, 510–512] had higher rates of HCO3−-dependent oxygen evolution (up to 369μmol/h per mg of chloroph…
Evidence for an oleoyl phosphatidylcholine desaturase in microsomal preparations from cotyledons of safflower (<i>Carthamus tinctorius</i>) seed Open
1. [14C]Oleoyl-CoA was metabolized rapidly and essentially completely by microsomal preparations from developing safflower (Carthamus tinctorius) cotyledons, and most of the [14C]oleate was incorporated into 3-sn-phosphatidylcholine. 2. In…
Labelling of glycerolipids in the cotyledons of developing oilseeds by [1-14C]acetate and [2-3H]glycerol Open
1. 3-sn-Phosphatidylcholine was identified as the major lipid in cotyledons from the developing seeds of soya bean, linseed and safflower when tissue was steamed before lipid extraction. The proportion of oleate in this lipid decreased mar…
Rapid temperature-induced changes in the fatty acid composition of certain lipids in developing linseed and soya-bean cotyledons Open
A change in ambient temperature caused marked alterations, over a 24h period, in the proportions of the unsaturated C18 fatty acids in 3-sn-phosphatidylcholine and 1,2-diacyglycerols during the development of soya-bean and linseed cotyledo…
Long-chain acyl-coenzyme A synthetase activity of spinach chloroplasts is concentrated in the envelope Open
Purified chloroplasts were disrupted and then fractionated by discontinuous sucrose-density-gradient centrifugation. Envelopes contained long-chain acyl-CoA synthetase at a specific activity 80 times the activity in the lamellae or the str…
Labelling studies <i>in vivo</i> on the metabolism of the acyl and glycerol moieties of the glycerolipids in the developing maize leaf Open
1. When [2-3H]glycerol was supplied to developing maize-leaf laminae, label entered 3-sn-phosphatidycholine at a linear rate essentially from zero time, whereas other lipids were labelled at accelerating rates. On transfer of laminae from …
High rates of [1-14C]acetate incorporation into the lipid of isolated spinach chloroplasts Open
Spinach chloroplasts, isolated by techniques yielding preparations with high O2- evolving activity, showed rates of light-dependent acetate incorporation into lipids 3-4 fold higher than any previously reported. Incorporation rates as high…
Growth of tropical and temperate grasses at Palmerston North Open
Warm-season yields of 14 C4-photosynthetic pathway tropical grasses were compared with yields of 6 C3-pathway temperate grasses, and observations were made on the extent of flowering and on frost sensitivity. Plants were grown in mono cult…
Some properties of a microsomal oleate desaturase from leaves Open
1. When [1-14C]oleoyl-CoA was incubated with a pea-leaf homogenate oleate was both incorporated into microsomal 3-sn-phosphatidylcholine and released as the unesterified fatty acid. The proportion of oleate incorporated into this phospholi…
The kinetics of incorporation <i>in vivo</i> of [14C]acetate and [14C]carbon dioxide into the fatty acids of glycerolipids in developing leaves Open
1. The patterns of incorporation of 14C into glycerolipid fatty acids of developing maize leaf lamina from supplied [1-14C]acetate and from 14CO2 during steady-state photosynthesis were similar. Oleate of phosphatidylcholine and palmitate …
Lipid Composition of Pea and Bean Leaves during Chloroplast Development Open
The changes in composition of the complex lipids were followed during the greening of dark-grown pea (Pisum sativum) and bean (Phaseolus vulgaris) seedlings. No significant changes in glycerolipid concentrations in the leaves were observed…
Turnover of the glycerolipids of pumpkin leaves. The importance of phosphatidylcholine Open
Between 1 and 5% of the 14C recovered from pumpkin leaves within 15–60min after pulse-labelling with 14CO2 was in the lipids. The specific radioactivity of the phospholipids was higher than that of the glycolipids. Phosphatidylcholine had …