Cellulose in the cell walls of the bangiophyceae (rhodophyta).

Mechanically isolated cell walls of the conchocelis phase of Bangia fuscopurpurea yield cellulose II (regenerated cellulose) upon treatment with Schweitzer's reagent. X-ray powder analysis and thin-layer chromatography of partial hydrolyzates confirm the presence of cellulose in this extract. Gas-liquid chromatographic analysis of wall hydrolyzates indicates that xylose, mannose, galactose, and glucose are major wall constituents. The presence of cellulose in the conchocelis provides evidence that this bangiophycean life cycle phase represents a transitional form or link between the two classes of red algae, Bangiophyceae and Florideophyceae. This suggests a close affinity of the two classes of the Rhodophyta and supports the hypothesis that bangiophycean algae were precursors of the Florideophyceae.

Glycogen and other soluble glucans from chytridiomycete and oomycete species.

Dry weight, protein, lipid, and glycogen were determined at various times during cultivation of the Chytridiomycetes, Rhizophydium sphaerotheca and Monoblepharella elongata. M. elongata had relatively stable levels of glycogen, but, in R. sphaerotheca, glycogen levels showed significant changes, particularly in older cultures in which a depletion of glycogen was accompanied by a marked thickening of the cell walls. Glycogen was a significant cellular constituent in both chytridiomycete species. In R. sphaerotheca and M. elongata, respectively, glycogen accounted for as much as 6% and 8.1% of the dry weight. In purified glycogens of both species, only alpha-1,4- and alpha-1,6-linked glucosyl residues were detected and the absorbance spectra of I2-complexes were similar to those of other well characterized glycogens. Purified Rhizophydium glycogen had a beta-amylolysis limit of 43%, and a CL of approximately 12. For the Monoblepharella polysaccharide, the respective values were 45% and 11. In extracts of the Oomycetes, Pythium debaryanum, Mindeniella spinospora, and Apodachlya sp., only beta-1,3- and beta-1,6-linked glucosyl residues were detected. These glucans were not iodophilic nor were they sensitive to alpha-amylase and beta-amylase. The properties of the oomycete polysaccharides suggested that they were similar to the mycolaminarans of Phytophthora spp. Although both investigated chytridiomycete species produced glycogen with typical properties, glycogen was apparently absent in the investigated Oomycetes.

Hyphal wall chemistry in Apodachlya.

Hyphal walls were isolated from the Oomycete, Apodachlya sp. Microscope examination of wall preparations showed that they were clean and relatively free of cellulin granules. The principal wall constituents, accounting for more than half of wall weight, were beta-glucans with 1,3- and 1,6-glucosidic linkages. Apparently chitin was the second most abundant wall constituent (18%) and cellulose accounted for less than 10% of wall weight. Protein was a significant wall constituent (6.4%), and protein hydrolysis demonstrated nearly all common amino acids plus hydroxyproline; additionally, the unusual amino acid, hydroxylysine was tentatively identified. The lipid and ash constituents were small (1.7and 0.4%, respectively) and no particular significance was assigned to them. The possible occurrence of wall glycoproteins and the relationship between wall chemistry and systematics in Apodachlya and related genera were discussed.

Composition of cellulin, the unique chitin-glucan granules of the fungus, Apodachlya sp.

Cellulin granules, the polysaccharide inclusions found uniquely in oomycetous fungi of the order Leptomitales, were isolated from Apodachyla sp. The granules were prepared free of cell wall and cytoplasmic contaminants. Biochemical analyses and X-ray diffraction studies demonstrated that the granules were composed of 60% chitin and 39% glucan consisting of beta-1,3- and beta-1,6-linked glucose units. A protein content of only 0.1% was attributed to an insignificant amount of cytoplasmic contamination. Isolated granules and those in situ showed no apparent differences in their microscopic form.

Glucans of oomycete cell walls.

The cell walls of selected oomycetous fungi are composed primarily of glucans, and cellulose constitutes a relatively small proportion of the total glucan. The noncellulosic constituents consist of acid-soluble glucan or glucans and insoluble glucan or glucans. These noncellulosic glucan fractions contain beta-(1-->3) glucosidic linkages and apparently beta-(1-->6) linkages also.