Summary. The yeast cells Saccharomyces cerevisiae grown up tostationary phase under either anaerobic conditions, or aerobic conditions in the presence of a respiratory inhibitor, antimycin A, had distinctive giant mitochondrial nucleoids (mt-nucleoids) (apparent diameter 0.6-0.9 ~tm) in contrast with the small mt-nucleoids (apparent diameter 0.2-0.4 ~m) in respiratory-sufficient cells grown aerobically, as revealed by DAPI-fluorescence microscopy. The cytoplasmic respiratory-deficient cells (rho-cells), which were induced by treatment of wild-type cells with ethidium bromide, showed both giant and small mt-nucleoids of irregular size. In order to examine the structural and functional differences between giant and small mtnucleoids, the former were successfully isolated from spheroplasts of three different cells by differential centrifugation and centrifugation on a discontinuous sucrose gradient. The isolated giant mt-nucleoids were intact in the morphology and were free of significant contamination by nuclear chromatin. The number of protein components involved in each of three different giant mt-nucleoids was similar to the number in small mt-nucleoids from aerobically grown cells, though a few noticeable differences were also recognized. DNAbinding proteins with molecular masses of 67 kDa, 52 kDa, 50 kDa, 38 kDa, 26 kDa, and 20 kDa were the main components of small mtnucleoids from aerobically grown cells as detected by chromatography on native DNA-cellulose. In contrast, the 67 kDa and 52 kDa proteins were hardly detected in corresponding fractions of giant mtnucleoids from anaerobically grown cells and from rho-cells grown aerobically. On the other hand, mt-nucleoids from aerobically grown cells in the presence of antimycin A seemed to lack the 67 kDa protein but to have a small amount of the 52 kDa protein. This is the first demonstration of the variance of protein species involved in yeast mt-nucleoids according to the respiratory activity of mitochondria.
It was previously reported that compared to triacylglycerol (TAG) oil, diacylglycerol (DAG) oil improves postprandial lipid response. However, the effects of DAG oil on postprandial hyperglycemia and incretin response have not yet been determined. In this study, the effects of DAG oil on both postprandial hyperlipidemia and hyperglycemia and the response to the glucose-dependent insulinotropic polypeptide (GIP) were studied. This randomized, double-blind, crossover study analyzed data for 41 individuals with high fasting triacylglycerol concentrations. The subjects ingested test meals (30.3 g of protein, 18.6 g of fat, and 50.1 g of carbohydrate) containing 10 g of DAG oil (DAG meal) or TAG oil (TAG meal) after fasting for at least 12 h. Blood samples were collected prior to and 0.5, 2, 3, 4, and 6 h after ingestion of the test meal. Postprandial TAG concentrations were significantly lower after the DAG meal compared with the TAG meal. Postprandial TAG, insulin, and GIP concentrations were significantly lower after the DAG meal compared with the TAG meal in 26 subjects with fasting serum TAG levels between 1.36 and 2.83 mmol/L. DAG-oil-based meals, as a replacement for TAG oil, may provide cardiovascular benefits in high-risk individuals by limiting lipid and insulin excursions.
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