The chemical composition of wool. xii further studies on cortical cells and macrofibrils

Abstract

Ultrasonication of Merino wool in formic acid liberates cuticle and then orthocortical cells. Further treatment produces a mixture of orthocortical and paracortical cells and finally a clean sample of paracortical cells is obtained. All chemical treatments of wool prior to ultrasonication are disadvantageous in the production of cortical cells. The paracortical cells are slightly denser than the orthocortical cells and this can be used as an additional method of separation of the two types of cells. Treatment of cortical cells with trypsin or IX-chymotrypsin removes the non-keratinous material and reduces the density of the cells. Ultrasonication for 3 h in formic acid of orthocortical and paracortical cells produces orthomacrofibrils and paramacrofibrils respectively in yields of 30-40 %. These particles are readily distinguished from one another by electron microscopy of sections stained with phosphotungstic acid. Their amino acid analyses are essentially the same as those of the orthocortical or paracortical cells from which they were prepared. The differences in amino acid analysis between orthocortex and paracortex agree, in general, with those found by previous workers. © 1974 ASEG.