(Biosynthesis and assembly of cell wall polysaccarides in cereal grasses): Progress report

Technical Report · Sun Jan 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/6380437· OSTI ID:6380437

Carpita, N. C.

We are investigating the biosynthesis of mixed-linkage ..beta..-D- glucan and glucuronoarabinoxylans which make up the hemicellulosic matrix of the primary cell walls of maize and other cereal grasses. The Golgi apparatus was enriched from plasma membrane and other organelles by flotation density gradient centrifugation. Glucan synthase I and II, which are established markers for Golgi and plasma membrane, respectively, displayed considerable overlap in conventional separations with sucrose density gradients. Flotation gradients improved separation of the membranes substantially, but the different synthases themselves also incorporated radioactivity from either 10 ..mu..M or 1 mM UDP-(/sup 14/C)-glucose into polymer. Relative incorporation of radioactivity into polymers from UDP-(/sup 14/C)-xylose by the various membrane fractions was nearly identical to relative IDPase activities, indicating that combined xylosyl transferase-xylan synthase represents a new, unequivocal marker for the Golgi apparatus. We developed techniques of gas-liquid chromatography and radiogas proportional counting to achieve capillary quality separation of partially methylated alditol acetates with simultaneous determination of radioactivity in the derivatives. We determined that both terminal and 4-linked xylosyl units from UDP-(/sup 14/C)-xylose and 3- and 4-linked glucosyl units from UDP-(/sup 14/C)-glucose were formed with Golgi membranes, whereas the plasma membranes made mostly 3-linked glucosyl units. We now are using digestion of polymeric products by specific endo-glycanohydrolases to diagnostic oligosaccharides that reveal specific kinds of polysaccharides synthesized by the Golgi membranes.

• Research Organization: Purdue Univ., Lafayette, IN (USA). Dept. of Botany and Plant Pathology
• DOE Contract Number: FG02-88ER13903
• OSTI ID: 6380437
• Report Number(s): DOE/ER/13903-T1; ON: DE89008417
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
140504* -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BIOMASS
BIOSYNTHESIS
CARBOHYDRATES
CELL CONSTITUENTS
CELL MEMBRANES
CELL WALL
CEREALS
DOCUMENT TYPES
ENERGY SOURCES
GRASS
ISOTOPE APPLICATIONS
LILIOPSIDA
MAGNOLIOPHYTA
MAIZE
MEMBRANES
ORGANIC COMPOUNDS
ORGANOIDS
PLANTS
POLYSACCHARIDES
PROGRESS REPORT
RENEWABLE ENERGY SOURCES
SACCHARIDES
SEPARATION PROCESSES
SYNTHESIS
TRACER TECHNIQUES