Platelike and globelike inclusion bodies associated with rough endoplasmic reticulum in alveolar type 2 cells of the sheep.
We studied the ultrastructure of alveolar type 2 cells of sheep. The inclusion bodies of rodlike structures or cisternal bodies derived from the endoplasmic reticulum were found in 13.6 +/- 7.0% (+/- SD) of type 2 cells. The length of the rodlike structure varied, the longest being 2.4 microns; but the width was usually 0.1 micron. Rod-like structures were usually straight and arranged in parallel stacks. An electron-dense line ran longitudinally at the center of the rodlike structures. Serial ultrathin sections revealed that the rodlike structures did not seem to be three-dimensionally rod-shaped structures but were actually plate-disc or cup-shaped, and the piled-up rodlike structures were connected to each other at their ends. This rodlike structure in type 2 cells of sheep seems rather to be a platelike inclusion body. The cisternal body, on the other hand, was circular or oval-shaped cisternae containing aggregated electron-dense materials distributed in an arabesque or speckled pattern. Serial ultrathin section examination revealed the cisternal body to be three-dimensionally a globe. Some plate bodies were arranged near the cisternal body, suggesting the transformation from the latter to the former. The functional significance of these findings has not yet been elucidated.
Shibamoto
T
T
First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Kobayashi
T
T
Nagata
T
T
D000818:Animals; D004721:Endoplasmic Reticulum / Q000648:ultrastructure*; D005260:Female; D002479:Inclusion Bodies / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000648:ultrastructure; D012756:Sheep / Q000033:anatomy & histology*