Factors Involved in the Production of a Novel Kind of Derangement of Storage Mechanism in Living Holotrich Giliate Protozoa from Sheep Rumen

Abstract

When metabolizing glucose or other fermentable sugar in vitro at a temperature 8–12° below the normal rumen temperature, three species of rumen holotrich ciliates were liable to exhibit highly abnormal appearances which were not seen at 35–38°. These abnormal appearances consisted essentially in a contraction and fusing together of the bulk of the storage polysaccharide (amylopectin) granules into a narrow central zone in the endoplasm. The outer clearer endoplasmic region, however, still contained numerous discrete granules in Isotricha prostoma and I. intestinalis but not in Dasytricha ruminantium. The abnormality was not quickly lethal to the organisms and appeared not to involve any alteration in shape or position of the macro-nucleus. The presence of rumen liquor, with all its soluble constituents but not necessarily its bacteria, is required for a high incidence of abnormality and the organisms should also initially contain but little storage polysaccharide. Evidence is presented in favour of the view that the abnormalities are connected with the utilization (auto-fermentation) of storage polysaccharide rather than with its synthesis. Nevertheless, the abnormalities cannot be induced in Isotricha when starch grains (vegetable or protozoan) have first been ingested.