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

Technical Report · Sun Jan 01 00:00:00 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
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

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