caa a22 4500 477101895 CHVBK 20180405111544.0 cr unu---uuuuu 170330e19960801xx s 000 0 eng 10.1007/BF00195185 doi (NATIONALLICENCE)springer-10.1007/BF00195185 Heterogeneity of the endoplasmic reticulum with respect to lipid synthesis in developing seeds of Brassica napus L [Elektronische Daten] [Dominic Lacey, Matthew Hills] Studies of the sub-cellular location of storage triacylglycerol (TAG) synthesis in developing embryos of oilseed rape (Brassica napus L.) show that there is heterogeneity of the endoplasmic reticulum (ER) with respect to the enzymes of lipid synthesis. The enzymes of TAG synthesis were detected in two membrane fractions (equilibrium densities 1.05 and 1.10 g· ml−1) isolated by sucrose-density-gradient centrifugation of homogenates from developing rape embryos. The synthesis of TAG by the lowdensity membranes has not been reported previously and was found in this study because the sucrose density gradients began at only 10% (w/w) sucrose. The pattern of activity of the enzymes involved in the synthesis of TAG in the higher-density fraction closely matched the marker enzymes for the ER; lyso-phosphatidylcholine acyltransferase and cytidine diphosphate-choline:diacylglycerol cholinephosphotransferase. The activity of the ER marker enzymes in the low-density membrane fraction, however, was very much lower when compared to those involved in the synthesis of TAG. Analysis of the lipids extracted from the low-density fraction revealed it contained about 50 mol% TAG compared with 15 mol% in the bulk ER, which may account for the low density of the membranes in this fraction. The possibility that the low-density membranes were the result of contamination of ER by oil bodies was ruled out by the use of oleosins as a marker for oil bodies. It is suggested that the low-density membranes are derived from a domain of the ER which is involved in the formation and secretion of TAG. Springer-Verlag, 1996 (Acyltransferase lipid synthesis) nationallicence Brassica nationallicence Endoplasmic reticulum nationallicence Oleosin nationallicence Seed (developing) nationallicence Triacylglycerol nationallicence CPT : cytidine diphosphate-choline:diacylglycerol cholinephosphotransferase nationallicence DAG : diacylglycerol nationallicence FPLC : fast protein liquid chromatography nationallicence Glc3P : glycerol-3-phosphate nationallicence LDM : ow-density membrane nationallicence LPC-AT : acyl-CoA: l-α-lyso-phosphatidylcholine O-acyltransferase nationallicence PA : phosphatidic acid nationallicence PC : phosphatidylcholine nationallicence PL : polar lipid nationallicence TAG : triacylglycerol nationallicence Lacey Dominic Department of Brassica and Oilseeds Research, John Innes Centre, NR4 7UH, Norwich, UK aut Hills Matthew Department of Brassica and Oilseeds Research, John Innes Centre, NR4 7UH, Norwich, UK aut Planta Springer-Verlag 199/4(1996-08-01), 545-551 0032-0935 199:4<545 1996 199 425 https://doi.org/10.1007/BF00195185 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00195185 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lacey Dominic Department of Brassica and Oilseeds Research, John Innes Centre, NR4 7UH, Norwich, UK aut NATIONALLICENCE 700 1- Hills Matthew Department of Brassica and Oilseeds Research, John Innes Centre, NR4 7UH, Norwich, UK aut NATIONALLICENCE 773 0- Planta Springer-Verlag 199/4(1996-08-01), 545-551 0032-0935 199:4<545 1996 199 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer