Ultrastructure of cultured mouse S91 melanoma cells with special emphasis on viral particles.
Mouse S91 melanoma cells which grow as a monolayer in culture were studied by transmission and scanning electron microscopy after fixation in situ. The cells were spindle-shaped and tended to grow in dense colonies. Melanosomes at all stages of melanization (stages I-IV) were observed. Other cell organelles reflected high cellular activity. Both A-type and C-type viral particles were abundantly observed. A-type particles were 60-90 nm in diameter. They had an electron-lucent center surrounded by a double shell. They were abundantly observed in the cisternae of the endoplasmic reticulum but never extracellularly. C-type retrovirus particles were larger, 80-110 nm in diameter. They had an electron-dense core surrounded by an electron-lucent area and a limiting membrane. They were seen to bud from the plasma membrane into intracellular vacuoles or into the intercellular space.
Department of Dermatology, University Central Hospital, Helsinki, Finland.
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Lauharanta
D000818:Animals; D002460:Cell Line; D008546:Melanoma, Experimental / Q000382:microbiology* / Q000648:ultrastructure; D051379:Mice; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012190:Retroviridae / Q000302:isolation & purification* / Q000648:ultrastructure