Biomedical subjects
Publications and source records attributed to R Douce.
Isolated plastids (chloroplasts and etioplasts) that are morphogically intact and free of any contamination from other cell structures can incorporate label from sn-glycerol-3-phosphate-(14)C into monogalactosyldiglyceride.
Mitochondria and plastids isolated from various plant tissues by methods which exclude contamination by other cell organelles lack phospholipase D activity.
In light or dark grown Euglena gracilis cells, the DPG content, in contrast to the PG content, is dependent on the carbon source. These results are closely related to the electron microscopy observations, showing structural changes in mitochondria varying with the carbon source of the media.Two media have been used: the first one contains L-glutamic and DL-malic acid and the second contains DL-lactic acid. The phospholipidic analysis shows that PC and PE are the two main phospholipids.
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The effect of glyphosate (N-phosphonomethyl glycine; the active ingredient of Roundup herbicide) on plant cells metabolism was analysed by 31P and 13C NMR using suspension-cultured sycamore (Acer pseudoplatanus L) cells. Cells were compressed in the NMR tube and perfused with an original arrangement enabling a tight control of the circulating nutrient medium. Addition of 1 mM glyphosate to the nutrient medium triggered the accumulation of shikimate (20-30 mumol g-1 cell wet weight within 50 h) and shikimate 3-phosphate (1-1.5 mumol g-1 cell wet weight within 50 h). From in vivo spectra it was demonstrated that these two compounds were accumulated in the cytoplasm where their concentrations reached potentially lethal levels. On the other hand, glyphosate present in the cytoplasmic compartment was extensively metabolized to yield aminomethylphosphonic acid which also accumulated in the cytoplasm. Finally, the results presented in this paper indicate that although the cell growth was stopped by glyphosate the cell respiration rates and the level of energy metabolism intermediates remained unchanged.
An outbreak of delta hepatitis occurred during 1998 among the Waorani of the Amazon basin of Ecuador. Among 58 people identified with jaundice, 79% lived in four of 22 Waorani communities. Serum hepatitis B surface antigen (HBsAg) was found in the sera of 54% of the jaundiced persons, and 14% of asymptomatic persons. Ninety-five percent of 105 asymptomatic Waorani had hepatitis B core (HBc) IgG antibody, versus 98% of 51 with jaundice. These data confirm that hepatitis B virus (HBV) infection is highly endemic among the Waorani. Sixteen of 23 (70%) HBsAg carriers identified at the onset of the epidemic had serologic markers for hepatitis D virus (HDV) infection. All 16 were jaundiced, where as only two of seven (29%) with negative HDV serology were jaundiced (P = .0006). The delta cases clustered in families, 69% were children and most involved superinfection of people chronically infected with HBV. The data suggest that HDV spread rapidly by a horizontal mode of transmission other than by the sexual route.