except in actinomycin d-treated cells , it was possible to identify two distinct components which are not visible in routinely prepared sections : ( 1 ) highly contrasted fibrillar clusters resulting from the loosening of the fibrillar component , ( 2 ) a granular network composed of nucleolar granules interconnected by a thin filament of about 5 nm in thickness .
C0007634
cells
C1179121
thin filament