Membrane lipid metabolism in germinating castor bean endosperm
Castor bean (Ricinus communis L. var. Hale) endosperms, excised after 2 days germination at 30/sup 0/C, were incubated 5 min to 8 hr with /sup 14/C-acetate and /sup 3/H-glycerol. Homogenates were fractionated by sucrose gradient centrifugation. Organelles found to be active in lipid synthesis were the lipid bodies and the endoplasmic reticulum. The products of incorporation in the lipid bodies were /sup 3/H-diglycerides containing /sup 14/C-fatty acids of more than 20 carbons. In contrast, the endoplasmic reticulum produced /sup 3/H-phospholipids, as well as /sup 3/H-diglycerides rich in /sup 14/C-linoleate. The phospholipids synthesized and their acyl contents were of the types known to be the major components of organelle membranes in this tissue. Phospholipids and diglycerides containing /sup 14/C and /sup 3/H were found in the glyoxysomes and mitochondria subsequent to their appearance in the endoplasmic reticulum. The results show that germinating castor bean endosperm synthesizes membrane lipids de novo from acetate rather than reutilizing stored lipid components directly. It is also apparent that the endoplasmic reticulum is responsible for several steps in membrane lipid production.
- Research Organization:
- Univ. of California, Santa Cruz
- OSTI ID:
- 6623689
- Journal Information:
- Plant Physiol.; (United States), Vol. 57
- Country of Publication:
- United States
- Language:
- English
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CASTOR
ENDOSPERM
LIPIDS
METABOLISM
ACETATES
BIOSYNTHESIS
CARBON 14
CELL CONSTITUENTS
CENTRIFUGATION
CYTOLOGY
ENDOPLASMIC RETICULUM
GERMINATION
GLYCEROL
MEMBRANES
MITOCHONDRIA
ORGANOIDS
PHOSPHOLIPIDS
PLANT CELLS
PLANTS
TISSUES
TRITIUM
ALCOHOLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGY
BODY
CARBON ISOTOPES
CARBOXYLIC ACID SALTS
ESTERS
EVEN-EVEN NUCLEI
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MEDICINAL PLANTS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PLANT TISSUES
RADIOISOTOPES
SEPARATION PROCESSES
SYNTHESIS
YEARS LIVING RADIOISOTOPES
550300* - Cytology
550301 - Cytology- Tracer Techniques