title: Spectroscopic and biochemical analysis of regions of the cell wall of the unicellular 'mannan weed', Acetabularia acetabulum.
abstract: Although the Dasycladalean alga Acetabularia acetabulum has long been known to contain mannan-rich walls, it is not known to what extent wall composition varies as a function of the elaborate cellular differentiation of this cell, nor has it been determined what other polysaccharides accompany the mannans. Cell walls were prepared from rhizoids, stalks, hairs, hair scars, apical septa, gametophores and gametangia, subjected to nuclear magnetic resonance and Fourier transform infrared spectroscopy, and analyzed for monosaccharide composition and linkage, although material limitations prevented some cell regions from being analyzed by some of the methods. In diplophase, walls contain a para-crystalline mannan, with other polysaccharides accounting for 10-20% of the wall mass; in haplophase, gametangia have a cellulosic wall, with mannans and other polymers representing about a quarter of the mass. In the walls of the diplophase, the mannan appears less crystalline than typical of cellulose. The walls of both diploid and haploid phases contain little if any xyloglucan or pectic polysaccharides, but appear to contain small amounts of a homorhamnan, galactomannans and glucogalactomannans, and branched xylans. These ancillary polysaccharides are approximately as abundant in the cellulose-rich gametangia as in the mannan-rich diplophase. In the diplophase, different regions of the cell differ modestly but reproducibly in the composition of the cell wall. These results suggest unique cell wall architecture for the mannan-rich cell walls of the Dasycladales.
authors.affiliation: Department of Biology, Center for Developmental Biology & Institute for Stem Cell and Regenerative Medicine, Box 35325, University of Washington, Seattle, WA 98195-5325, USA.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Dunn
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Shoue
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Kline
authors.forename: Alex L
authors.initials: AL
authors.lastname: MacKay
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Carpita
authors.forename: Iain E P
authors.initials: IE
authors.lastname: Taylor
authors.forename: Dina F
authors.initials: DF
authors.lastname: Mandoli
mesh_terms: D000076:Acetabularia / Q000166:cytology* / Q000502:physiology; D020418:Algal Proteins / Q000737:chemistry / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D018929:Cell Culture Techniques; D002473:Cell Wall / Q000648:ultrastructure*; D003460:Crystallization; D005583:Fourier Analysis; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry / Q000378:metabolism; D008745:Methylation; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D020418:Algal Proteins; D000596:Amino Acids; D008351:Mannans