A study of the carbohydrates in the cell walls of some species of the Entomophthorales

Hoddinott, John (1970) A study of the carbohydrates in the cell walls of some species of the Entomophthorales. Masters thesis, Memorial University of Newfoundland.

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Abstract

The Entomophthorales were studied to determine whether a new criterion could be introduced into their scheme of classification to help clarify some of the synonymy within the group. An attempt was also made to see if differences in the cell wall carbohydrates showed any correlation with the differences in mycelial lipids within the group. It was also desirable to find out if the Entomophthorales were of similar cell wall composition to the Mucorales, and if not to which chemical category they should be assigned. -- Several media were tested to see which one supported the best fungal growth, and several extraction techniques were tested to see which gave the most useful cell wall preparations free of cytoplasm. The efficiency of the cell wall extractions was determined histochemically. -- A histochemical study of the cell wall was made to provide qualitative data on the constituent polysaccharides in the cell walls. Further qualitative data was gained by hydrolysing the cell walls and analysing by chromatography the monosaccharides so released. Quantitative data were gathered by analysing the hydrolysates by colourimetric techniques. -- It was shown as a result of this study that qualitative differences occur between the genera tested, and that quantitative differences occur between the species of one genus. The glucose: mannose ratio is the most useful taxonomic criterion at the species level, as it remains constant on a variety of media. -- The sub-grouping of the Entomophthorales by their lipid composition seems to be reflected in the cell wall carbohydrate composition. -- The Entomophthorales should not be classed chemically with the Mucorales; they should be separated into a category of chitin-glucan fungi.

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