The occurrence of methylated carbohydrates and rhamnose as components of soil polysaccharides

Abstract

oils, fully saturated triglycerides do not occur in significant proportions unless the unsaturated acid content is below that (about 350/6) necessary to permit of each mixed triglyceride molecule containing one unsaturated acyl group. On this assumption tiger fat which contains about jI% unsaturated acids should not contain any trisaturated glycerides. But land-animal fats stand apart from this rule and many fats (ox, sheep etc.) show a much higher content of trisaturated glycerides. From the graph in which the contents of fully saturated glycerides were plotted against saturated acids of land-animal fats (Hilditch, 1947, p. 303), we find that the content of trisaturated glycerides should be about 3% higher than the observed value for the tiger fat under discussion. As mentioned before, the quantity of fat available was insufficient to permit a separate determination of fully saturated glycerides by the method of Hilditch & Lea (1927) ; in this case the matter would have been clear, as we believe that a small quantity of fully saturated glyceride would have passed into fraction B. Taking this to be true, our figure for fully saturated glyceride might approach 9%. On the other hand, as the component glycerides of no other carnivorous-animal fat is available, no comparable data can be quoted. The fully saturated glyceride content of tiger fat, however, compares well with that of a ewe (Hilditch & Zaky, 1941) (external) fat which contains 50% of saturated acids and 5% of fully saturated glycerides.The similarity in the fatty acid composition to that of other land-animal fats suggests that at least some of the glycerides from the diet have been deposited as such. If this be so then the proportion of fully saturated glycerides is rather lower than expected. If it is assumed that no fully saturated glycerides have passed into fraction B, i.e. that their observed content is the true content, then it appears that some bio-dehydrogenation has taken place.

The Adsorption of Sugars by Montmorillonite

“…Soil polysaccharides have been shown to contain simple sugars and sugar acids (Forsyth, 1950), sugar amines (Bremner,19 o), and methyclays can occur through any or all of the mechanisms so far discussed, oxygen atoms such as exist on the interlame P lar surfaces of montmorilgroups to neutralize the sur 7 ace charge of the clay may contribute to the lated sugars (Duff, 1952). Thus the adsorption of soil PO I ysaccharides by In g./Ioo g. dry clay.…”

The Adsorption of Sugars by Montmorillonite Ii. Chemical Studies

“…Soil polysaccharides have been shown to contain simple sugars and sugar acids (Forsyth, 1950), sugar amines (Bremner,19 o), and methyclays can occur through any or all of the mechanisms so far discussed, oxygen atoms such as exist on the interlame P lar surfaces of montmorilgroups to neutralize the sur 7 ace charge of the clay may contribute to the lated sugars (Duff, 1952). Thus the adsorption of soil PO I ysaccharides by interesting to note that the magnitude of the adsorption is considerably greater than the adsorptions of fulvic and humic acids that have previously been reported Jung, 1943; Khan, 1950;1951).…”

Decomposition of Soil Polysaccharide

“…They also found that alanine, glycine, aspartic acid, and glutamic acid were the predominant amino acids present. Incubation experiments: materials employed (Duff, 1952;Whistler and Kirby, 1956 Infrared analysis of the polysaccharide showed absorption characteristic of three types of structure; acidic polysaccharide, peptide, and polymerized phosphate.…”