Nucleoids and coated vesicles of "Epulopiscium" spp.

We describe here aspects of the anatomy of two "Epulopiscium" morphotypes, unusually large bacteria that are not yet cultured and that reproduce by the internal generation of two or more vegetative daughter cells. Two morphotypes, A and B, which are enteric symbionts of several species of herbivorous surgeonfish (Acanthuridae), were collected around the Great Barrier Reef of Australia, preserved there, and later stained for light microscopy. Some samples were examined by electron microscopy.

The bacterial nucleoid revisited.

This review compares the results of different methods of investigating the morphology of nucleoids of bacteria grown under conditions favoring short generation times. We consider the evidence from fixed and stained specimens, from phase-contrast and fluorescence microscopy of growing bacteria, and from electron microscopy of whole as well as thinly sectioned ones. It is concluded that the nucleoid of growing cells is in a dynamic state: part of the chromatin is "pulled out" of the bulk of the nucleoid in order to be transcribed.

An anticancer drug-sensitive murine erythroleukemia clone: implications for the mechanism of action of antineoplastic drugs.

The mechanism(s) by which anticancer drugs kill tumor cells remains obscure. The studies reported here were undertaken with the view that the mechanism may be understood in part through an analysis of anticancer drug-sensitive clones. We have isolated a murine (Friend) erythroleukemia clone in which drug sensitivity was correlated with increased differentiation, suggesting that anticancer drug-induced cell death may be based on differentiation or a differentiation-dependent mechanism.