Nucleus-specific and temporally restricted localization of proteins in Tetrahymena macronuclei and micronuclei

Labeled nuclear proteins were microinjected into the cytoplasm of Tetrahymena thermophila. Macronuclear H1, calf thymus H1, and the SV40 large T antigen nuclear localization signal linked to BSA accumulated specifically in macronuclei, even if cells were in micronuclear S phase or were nonreplicating. The way in which histone H4 localized to either the macronucleus or the micronucleus suggested that it accumulates in whichever nucleus is replicating. The inability of the micronucleus to accumulate Tetrahymena H1 or heterologous nuclear proteins, even at a period in the cell cycle when it is accumulating H4, suggests that it has a specialized transport system. These studies demonstrate that although the mechanism for localizing proteins to nuclei is highly conserved among eukaryotes, it can differ between two porecontaining nuclei lying in the same cytoplasm.     

The flocculation of yeast with chitosan in complex fermentation media: The effect of biomass concentration and mode of flocculant addition

Summary The minimum effective dose of chitosan necessary to flocculate a suspension of yeast in a complex medium is not proportional to the yeast concentration in the medium and is dependent upon the mode of addition of the flocculant to the suspension.     

Spontaneous wasting disease in nude mice associated with Pneumocystis carinii infection

Several cases of wasting disease and dyspnea occurred in outbred Crl: CDI(ICR) nu/nu mice obtained recently from a commercial supplier. Gross necropsy revealed pulmonary consolidation, and histologically there was alveolar-wall thickening and filling of alveoli with macrophages and honey-combed eosinophilic material. Electron microscopic examination of lung tissue confirmed infection with Pneumocystis carinii.