Osmoregulatory mutants of Saccharomyces cerevisiae with a defect in their capacity to readjust the cell volume/buoyant density after osmotically induced dehydration were enriched by density gradient centrifugation. Colonies derived from cells that remained dense after dehydration were screened for sensitivity to high concentrations of NaCl and defects in their osmotically induced production and intracellular accumulation of glycerol. The isolated osg (osmosensitive glycerol defective) mutants were recessive in heterozygous diploids and fell into four complementation groups (osg1-osg4). The osg1-1 mutant, described in this work, is unable to grow at low water potential and shows a decreased capacity for glycerol production and a strongly reduced activity of NAD(+)-dependent sn-glycerol 3-phosphate dehydrogenase (GPD), an enzyme in the glycerol-producing pathway. Complementation of the osg1-1 salt sensitivity defect with a low copy yeast genomic library led to the cloning of GPD1, encoding an S. cerevisiae GPD consisting of 391 amino acids and sharing 47-50% identity with GPD from other sources. Micro-sequencing of the N-terminus of purified S. cerevisiae GPD revealed a 20-amino-acid sequence that was identical to a nucleotide-deduced amino acid sequence in GPD1, but indicated that the enzyme is produced with an N-terminal extension that is removed from the functional enzyme. Subcellular fractionation does not indicate, however, that the putative pre-sequence targets GPD to any organelle; the enzyme appears to be located in the cytoplasm. Chromoblot and tetrad analysis were used to position the GPD1 gene to chromosome IV, with a distance of about 18 cM from trp1.

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Preemptive therapy based on polymerase chain reaction for CMV DNA was associated with reduced risks for CMV disease, CMV-associated death, and TRM, whereas other prophylactic modalities did not give additional benefit.

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Having an ileostomy does not seem to affect patients' quality of life, while having ileoanal anastomosis appears to reduce patients' quality of life in several of the dimensions assessed. CD patients reported more anxiety and depression than did patients with UC. The higher psychological distress in the CD group could be explained by more severe symptoms of the disease. Having ileoanal anastomosis may lead to more anxiety and depression, while having an ileostomy does not.

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By complementation of a salt-sensitive mutant of Saccharomyces cerevisiae, we cloned the SOP1 gene, encoding a 114.5-kDa protein of 1033 amino acids. Cells deleted for SOP1 exhibited sensitivity to sodium stress, but showed no sensitivity to general osmotic stress. Following exposure of sop1⌬ cells to NaCl stress, the intracellular Na ؉ level and the Na ؉ /K ؉ ratio rose to values significantly higher than in wild type cells. Deletion of SOP2, encoding a protein sharing 54% amino acid identity with Sop1p, produced only slight Na ؉ sensitivity. Cells carrying a sop1⌬sop2⌬ double deletion became, however, hypersensitive to Na ؉ and exhibited increased sensitivity also to Li ؉ and K ؉ , suggesting involvement of both SOP1 and SOP2 in cation homeostasis. The predicted amino acid sequences of Sop1p and Sop2p show significant homologies with the cytoskeletal-associated protein encoded by the Drosophila lethal(2)giant larvae tumor suppressor gene. Immunolocalization of Sop1p revealed a cytoplasmic distribution and cell fractionation studies showed that a significant fraction of Sop1p was recovered in a sedimentable fraction of the cytosolic material. Expression of a Drosophila l(2)gl cDNA in the sop1⌬sop2⌬ strain partially restored the Na ؉ tolerance of the cells, indicating a functional relationship between the Sop proteins and the tumor suppressor protein, and a novel function in cell homeostasis for this family of proteins extending from yeast to human.