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.

The Cell Walls of Green Algae: A Journey through Evolution and Diversity

“…Some of them have cellulose as a major fibrillar component of their cell walls. However, others possess (1→4)-β-mannans or (1→3)-β-xylans (Percival and McDowell, 1981; Painter, 1983; Yamagaki et al, 1997; Dunn et al, 2007; Estevez et al, 2009; Ciancia et al, 2012) and in some, the type of fibrillar polysaccharide is life cycle stage-dependent (Huizing and Rietema, 1975; Wutz and Zetsche, 1976; Huizing et al, 1979; Dunn et al, 2007). …”

Beyond the Green: Understanding the Evolutionary Puzzle of Plant and Algal Cell Walls

“…Dunn et al (2007), and Love and Percival (1964). i mAb labeling and extraction followed by radial gel diffusion .…”

“…1). Since mannans are known to occur in green algae, including Codium fragile ) and Acetabularia acetabulum (Dunn et al, 2007), the products of CslA/CslC could be responsible for mannan synthesis. CslA/CslC appears to be absent from brown and red algae (Yin et al, 2009; Fig.…”

Expression of Trichoderma reesei β-Mannanase in Tobacco Chloroplasts and Its Utilization in Lignocellulosic Woody Biomass Hydrolysis

“…Lignocellulosic biomass rich in mannans include softwood from gymnosperms such as pinewood (10%), poplar wood (4%), and cellulose sludge (4%) (United States Department of Energy, (http://www1.eere.energy.gov/biomass/feedstock_databases.html). Algae including Acetabularia and Porphyra contain up to 20% mannans in their cell wall [7], [8], which can be utilized for ethanol production [9]. Algae are also important producers of biodiesel, after the lipids are extracted for biodiesel production; the remaining waste is rich in carbohydrates and can be used as a substrate for bioethanol production [9].…”