Three-dimensional demonstration of the intracellular structures of mouse mesothelial cells by scanning electron microscopy.
Intracellular structures of mouse mesothelial cells lining the small intestine were studied by scanning electron microscopy. Specimens were prepared by the freeze-polishing method which permitted demonstration of the attenuated thin layered organization of the intracellular structures. When the surface cell membrane had been partially turned over during the specimen preparation procedure, many pinocytotic vesicles were observed attached to the cytoplasmic side of the cell membrane. We also demonstrated the external side of the basal cell membrane on which many openings of the pinocytotic vesicles were clearly shown as those recognized on the free cell surface. Two adjacent pinocytotic vesicles often appeared fused together. The multivesicular vacuole formed by the congregation of the pinocytotic vesicles were sometimes recognized on the cytoplasmic side of the surface and basal cell membrane. On the nuclear surface, nuclear pores and polysomes were visible. From our SEM findings, we classified the rough endoplasmic reticulum into three types: type I, II and III. The type I rough endoplasmic reticulum was composed of flat cisternae with fenestration, the type II of polygonal flat cisternae without fenestration, and the type III of vesicular cisternae. Polysomal formation is evident in the type III, but less in the type I and II. All of the endoplasmic reticulum appeared connected each other forming a continuous system in the cell. Two kinds of the Golgi apparatus were recognized: a stretched type with highly extended Golgi cisternae and a shrunken type with less developed Golgi cisternae. In the latter, lots of Golgi vesicles were attached on the periphery of the cisternae, and the outermost cisterna was commonly fenestrated.
Inoué
T
T
Department of Anatomy, Tottori University School of Medicine, Yonago, Japan.
Osatake
H
H
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure; D003238:Connective Tissue / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D005260:Female; D006056:Golgi Apparatus / Q000648:ultrastructure; D002479:Inclusion Bodies / Q000648:ultrastructure; D007421:Intestine, Small / Q000166:cytology / Q000648:ultrastructure*; D008297:Male; D008648:Mesoderm / Q000166:cytology* / Q000648:ultrastructure; D051379:Mice; D008815:Mice, Inbred Strains; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008928:Mitochondria / Q000648:ultrastructure; D009685:Nuclear Envelope / Q000648:ultrastructure