Cell Wall Composition of the Generic Phase of Bangia atropurpurea (Rhodophyta)

Abstract

Mechanically isolated cell walls were prepared from the generic phase of Bangia atropurpurea and chemically characterized. Electron microscopic examination of cell wall preparations revealed them to be morphologically similar to walls of whole thalli and free from protoplasmic contamination. The chemical composition of over 92% of the total wall weight was determined and polysaccharides were the major wall components (72% of wall weight). Mannan (at least part of which is 0-1,4-linked) and a water soluble galactan fraction consisting of both D-and L-galactose residues in a ratio of l: 1.1 represents a large proportion of the carbohydrate content of isolated cell walls. In addition, 3,6-anhydrogalactose is probably associated with the water-soluble galactoses. The presence of cellulose could not be demonstrated. Protein was a significant wall component (10.6% of total wall weight) and consisted of at least 16 aminoacids, including hydroxyproline (0.3% of wall weight). Walls also contained 8.4% lipid and l .4% ash.

Cell Wall Composition of the Conchocelis Phases of Bangia atropurpurea and Porphyra leucosticta (Rhodophyta)

“…Mechanically isolated cell walls were fractionated by sequential extraction (Gretz et al 1982). Various hydrolytic methods and time course studies were used to determine maximum yields of monosaccharides from cell wall and wall fraction hydrolyzates.…”

“…Various hydrolytic methods and time course studies were used to determine maximum yields of monosaccharides from cell wall and wall fraction hydrolyzates. Hydrolysis was done by the fuming HCl-trifluoracetic acid (TFA) procedure (Gretz et al 1982). Monosaccharides were identified and quantified by gas-liquid chromatography (GLC) and paper ciromatography (PC) (Gretz et al 1982).…”

“…(P. leucostricta (sie) Gretz et al 1983Gretz et al , 1984 was provided by the Culture Collection of Algae, University of Texas, Austin (LB 1415). The algae were fragmented and allowed to grow vegetatively in liter flasks containing 300 ml of sterile medium (Gretz et al 1982). B. atropurpurea was maintained at 21 °C and P. leucosticta at 15 °C on a 18/6 LD cycle (approximately 50 μπιοί mr 2 s" 1 ) for 60 d. Prior to harvest cultures were allowed to remain in the dark for 8 d (at 21 °C and 15 °C, respectively) to deplete the floridean starch reserve, a potential source of polysaccharide contamination of isolated walls.…”

“…Mechanically isolated cell walls were prepared by a modification of the methods of Gretz et al (1982). During all Steps in the Isolation procedure, material was maintained in cold (3-5 °C) 0.1 M Tris/HCl buffer (pH 7.5).…”

“…The clean walls were washed twice with cold water and freeze-dried giving a white material which was used for all analyses. The purity of these isolated wall preparations was conflrmed by light and electron microscopy and Chlorophyll determinations s previously described (Gretz et al 1982). Cellulose was detected cytochemically in isolated walls of both B. atropurpurea and P. leucosticta using KI 3 -65% H 2 SO 4 (Jensen 1962).…”