THE ROLE OF LIGHT IN THE SYNTHESIS OF LIPIDS IN FRUITS (thesis)

Technical Report · Fri Jan 01 04:00:00 EST 1960

OSTI ID:4834256

Developing flax (Limim usitatissimum L.) embryos cultured in vitro were used for thc study of the role of light in fat synthesis. White light and biotin in combination were absolute requirements for maximum incorporation of carboxyl- labeled acetate in lipids. Light not only enhanced fat synthesis, but inhibited the conversion of labeled acetate into CO/sub 2/. Adenosine triphospbute (ATP) and biotin were necessary for fut synthesis in embryos maintained in the dark in order to bring the specific activity of fat to that obtained in the light without the addition of these cofactors. The results indicated that light may generute ATP through photosynthetic pbosphorylation. Only blue and red light were effective in stimuluting fat synthesis from labeled acetate. The addition of reduced diphosphopyridine nucleotide (DPNH) to the culture increased fat synthesis and CO/sub 2/ evolution 2 to 3-fold. On the contrary, reduccd triphosphopyridine nucleotide (TPNH) and coenzyme A had sligbt inhibitory effects. Malonate, in the absence of carb xyllabeled acetate, enhanced tbe synthesis of fat. This suggested that malonic acid at low concentrutions can serve as a precursor for the syntbesis of long-chain fatty acids. Furthermore, light affects the type of fatty acids formed in flax embryos and increases the degree of unsaturution. Under light conditions, di- and trienoic acids are the dominant fatty acids. Tbe stimulatory effect of low intensity red light on fat synthesis can be reversed by far-red light. This effect of red light on the utilization of acetate for fat synthesis cannot be reversed by far-red light after an hour and a half. lt is concluded that red and far-red light, of relatively lou intensity, can shift tbe use of acetate metabolism in one direction or another. (auth)

• Research Organization: Arizona. Univ., Tucson
• NSA Number: NSA-16-001810
• OSTI ID: 4834256
• Report Number(s): TID-14243
• Country of Publication: United States
• Language: English

Related Subjects

ACETATES
ADENOSINE
ADENOSINE TRIPHOSPHATE
ATP
BIOTIN
CARBON DIOXIDE
CHEMISTRY
DPNH
ENZYMES
ESTERS
FRUIT
LABELLED COMPOUNDS
LIGHT
LIPIDS
METABOLISM
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHOTOSYNTHESIS
PLANNING
PLANT CELLS
PLANTS
PREPARATION
PYRIDINES
QUALITATIVE ANALYSIS
QUANTITY RATIO
REDUCTION
RIBONUCLEIC ACID
VITAMIN H
VITAMINS