Abstract
The influence of the fixative on staining with P. T. A. of thin section was studied on the electron microscope. Normal mouse lung, experimental lung tumour by means of 4-Nitroquinoline N-oxide and tuberculous granulomatous tissue in the rabbit lung were carried on this experiment.
P. T. A. has been used as an electron stain in different techniques. Some of its most suitable applications have been the satining of connective tissue fibres and plasma membrane of various types of cells. Floating thin sections were stained with P. T. A. after the bleaching with periodic acid (Marinozzi et al.). By means of P. T. A. staining, an elegant visualization of the elastic tissue in normal mouse lung, experimental lung tumour and others was possible when the samples were fixed in glutaraldehyde only, or were fixed in. glutaraldehyde, postfixed in osmium tetroxide, and then embedded in Epon 812.
Collagen fibres and plasma membranes were stained under these ways. However, when high pH values of P. T. A. solution (higher than pH 1. 9) were employed, their stainability came to decrease. On the contrary, plasma membrane derivatives, i. e. pinocytes and multivesicular bodies, and nucleus and ribonucleic particles came to show the stainability to P. T. A. When the staining was applied to a sample which had been fixed only with osmium tetroxide, the stainability of the elastic tissue was weaker and less specific. Galgi apparatus, membranous components of endoplasmic reticulum and nuclear membranes were never stained with P. T. A. The unit membrane was demonstrable not only on the plasma membranes, but on the pinocytes, multivesicular bodies, endoplasmic reticulum and mitochondria also, all of which are considered to display continuity. However, their membrane components had different stainability to P. T. A.
It is supposed that the stainability to P. T. A. depends upon the molecular structure of the unit membrane in each membranous organella, especially on the various state whichh might change according to the physiological conditions of the cells and the functions of the organella itsself.
