Showing papers on "Lipid biosynthesis published in 1971"

The lipid metabolism of blood and culture forms of Trypanosoma lewisi and Trypanosoma rhodesiense.

Abstract: 1. 1. Lipid biosynthesis, uptake and oxidation of fatty acids by blood and culture forms of Trypanosoma lewisi and T. rhodesiense were studied in vitro. 2. 2. With the exception of blood T. rhodesiene, trypanosomes incorporated radioactive glucose, glycerol and acetate into total lipids. Culture trypanosomes incorporated radioactive acetate into saturated and unsaturated long-chain fatty acids. Blood T. lewisi synthesized stearate only. 3. 3. Saturated and unsaturated C16 and C18 acids were absorbed, interconverted, and esterified by all trypanosomes. Highest activity was found in phospholipids of blood forms. Stearate uptake showed anomalies and α-linolenate uptake was particularly rapid in culture T. rhodesiense. 4. 4. Palmitate oxidation was low or insignificant in both species.

Influence of Age on in Vitro Lipid Biosynthesis and Enzymatic Activity in Pig Adipose Tissue

Abstract: SummaryLipogenesis, as measured by the incorporation of glucose-U-14C into fatty acids by adipose tissue slices was determined periodically in 8 pigs from the age of 35 days (9.0 kg) to 180 days (90.0 kg). In the suckling pig, the capacity for fatty acid synthesis was very low, presumably due to the high-fat content of sow milk. Upon ingestion of the high-carbohydrate diet, fatty acid synthesis increased rapidly and reached a peak at 67 days of age. From 67 days of age there was a gradual decrease in the capacity for fatty acid synthesis with advancing age. Changes in the activities of citrate-cleavage enzyme and malic enzyme occurred in parallel with the changes in fatty acid synthesis, supporting the participation of these enzymes in lipogenesis in pig adipose tissue.

Lipid biosynthesis by isolated barley chloroplasts in relation to plastid development.

Abstract: The effect of seedling age and of the time of greening on the incorporation of 1-(14)C-acetate into lipids by isolated barley (Hordeum vulgare cultivar Svalof's Bonus) plastids was examined. The fatty acid synthesizing capacity of plastids isolated from 5-day-old seedlings did not increase markedly from zero to 36 hours of greening nor was a light stimulation of fatty acid synthesis observed. However, an increasing capacity for fatty acid synthesis and an increasing light stimulation of this process with greening were attained by the plastids isolated from 7-, 9-, and 11-day-old seedlings.Plastids of 7-day-old dark-grown plants, which were illuminated at 2 foot-candles showed increasing capacity of (14)C-acetate incorporation with significant flow into phospholipids and sulfolipid, low flow into digalactosyl diglyceride, and considerable flow into 6-methyl salicylic acid. Exposure of these plants to high light intensity for an hour resulted in chloroplasts that after isolation had a 10-fold increased capacity to incorporate (14)C label into digalactosyl diglyceride, while the flow of (14)C label into phospho- and sulfolipids was unaltered, and that into 6-methyl salicylic acid was drastically curtailed.With plastids from 7-day-old dark-grown plants in early stages of greening, essentially all the (14)C label in the stroma fraction could be accounted for by 6-methyl salicylic acid, while the membrane lipids only contained small amounts of (14)C label. As greening proceeded, the flow of (14)C label into 6-methyl salicylic acid diminished sharply, and the lipids of the lamellar systems became increasingly labeled.Only palmitic and oleic acids were main sites of (14)C label in the membrane lipids.The activity of acetyl CoA carboxylase present in plastids of 5- and 7-day-old dark-grown plants fell sharply as the etioplasts differentiated into chloroplasts.

Studies on the Fungicidal Action of Dithiocarbamates

Abstract: The effect of sodium dimethyldithiocarbamate (NaDMDC) on Xanthomonas oryzae, a causative pathogen for bacterial leaf blight of rice plant, was investigated. The growth of X. oryzae in liquid medium was completely suppressed at a concentration of 50μg/ml when the fungicide was added immediately after inoculation, and at the mid-logarithmic growth it was also suppressed about 50 per cent at a concentration of 100μg/ml.Oxygen uptakes by endogenous respiration and substrate oxidation were slightly accelerated by the concentration less than 50μg/ml, whereas at the higher concentration, the oxygen uptakes were somewhat inhibited, among the several kinds of substrate, succinate oxidation was most markedly inhibited. But succinate dehydrogenase activity in cell-free extracts of X. oryzae was almost not inhibited by 10μg/ml NaDMDC.The incorporations of amino acids-14C into protein and of glucosamine-14C into cell wall were not inhibited even at a concentration of 100μg/ml. The incorporations of uridine-14C and thymidine-14C into RNA and DNA respectively were considerably inhibited by 100μg/ml NaDMDC, while adenine-14C, orotic acid-14C, glycine-14C and H332PO4 were not inhibited at the same concentration. Thus it is assumed that NaDMDC acts against incorporation of nucleosides into nucleic acids. However, the most remarkable inhibition was observed in the lipid synthesis. The incorporation of acetate-14C into lipid was inhibited approximately 50 per cent by 100μg/ml NaDMDC, and under the presence of glucose the inhibition reached to 90 per cent at the same concentration. Furthermore, the incorporations of pyruvate-14C and H332PO4 into lipid were remarkably inhibited.These results indicate clearly that the possible site of NaDMDC action against X. oryzae may be the process of lipid biosynthesis.