Nucleoli in a macronucleus of a cell undergoing micronuclear division. The nucleolus appears to have an organized surface layer composed of parallel threads of subunits. These may be developing riboso...

A high resolution image of the micronucleus and macronucleus of Opercularia coarctata. The nuclear envelope has numerous pores, at least as many per unit length as in the macronucleus. Some areas of t...

Transmission electron micrograph of the salivary gland of the tick Rhipicelphals appendiculatus illustrating the dramatic difference in nuclear size seen in different cell types. Here, the large (prob...

Transmission electron micrograph of nucleus showing the characteristic features of glutaraldehyde fixation introduced as a primary fixative in 1962 and since used routinely. Chromatin appears differen...

Transmission electron micrograph illustrating the accumulation of dense heterochromation that accompanies terminal differentiation in may cells. Shown here is a section through a polychromatophilic er...

Upper panel shows a transmission electron micrograph featuring the nuclear envelope with the nuclear lamina seen here as a uniform layer between the inner nuclear membrane and more darkly staining blo...

Shown are fibroblasts from a Hutchinson-Gilford Progeria syndrome patient which carries a mutation in the gene for lamin A (red), a major component of the nuclear lamina. The morphology of the envelop...

Shown is a fibroblast from a Hutchinson-Gilford Progeria syndrome patient which carries a mutation in the gene for lamin A (left image, red), a major component of the nuclear lamina. Also shown is th...

Transmission electron micrograph of a thin section of the nucleus of a HeLa cell expressing a mutant of the nuclear porin ALADIN. The nuclear envelope ultrastructure is not affected by the mutation. ...

Grazing thin section through the nuclear envelope of a macronucleus. Nuclear pores are packed so tightly that they often form a hexagonal array with 6 pores surrounding a central pore. The pores often...