* Correspondence: [email protected]

The transcription initiation site of the Saccharomyces cerevisiae PRS1 gene was mapped at -179 bp. Measurement of beta-galactosidase activity of the successively deleted PRS1 promoter linked to lacZ and integrated at the ura3 locus defined three DNA regions involved in the control of PRS1 expression. Gel shift analysis confirmed the data.

(shaded bars; left scale) are presented beside β-gal activity units determined on the indicated strains in the same conditions by ONPG-based assays (empty bars; right scale), performed using the traditional Miller method for bacteria (3) and crude protein extracts for yeast (1). MUG, 4-methylumbelliferyl β-d-galactopyranoside; ONPG, o-nitrophenyl-β-d-galactopyranoside; β-gal; β-galactosidase. B...

Rohlfing, S. R. (Western Reserve University, Cleveland, Ohio), and I. P. Crawford. Purification and characterization of the beta-galactosidase of Aeromonas formicans. J. Bacteriol. 91:1085-1097. 1966.-The beta-galactosidase of Aeromonas formicans was purified by diethylaminoethyl cellulose chromatography and gel filtration on Sephadex G-200. The properties of the enzyme molecule were compared w...

An improved method is described for the preparation of bovine testicular beta-galactosidase that allows the isolation of enzyme fractions that bind avidly to phosphomannosyl receptors. The procedure permits removal of a contaminating beta-hexosaminidase and yields nearly homogeneous beta-galactosidase. Enzyme eluted from DEAE-Sephacel was arbitrarily divided into pools that exhibited differing ...

PURPOSE To investigate the relation of senescence-related beta-galactosidase activity and telomere shortening to replicative senescence in cultured human retinal pigment epithelial (RPE) cells. METHODS A human RPE cell line was serially passaged until 80% of cells were nondividing in a 72-hour 5-bromo-2'-deoxyuridine (BrdU) labeling study. Early- and late-passage cells were double-stained for...

When a strain of Escherichia coli, expressing a hybrid protein GalK-beta-Gal, is shifted to high osmolarity, the beta-galactosidase activity strongly decreases within 20 min of shock. The loss of beta-galactosidase activity results from degradation of the hybrid protein under osmotic stress. The results raise the possibility that osmotic stress induces a specific osmodependent protease.

We report a significantly improved system for studying single-copy lacZ operon fusions in Yersinia enterocolitica: a simple procedure for the stable integration of lacZ operon fusions into the ara locus and a strain with a deletion mutation that abolishes the low level of endogenous beta-galactosidase activity.

A flocculent Saccharomyces cerevisiae strain was engineered to stably secrete Aspergillus niger beta-galactosidase in a continuous high-cell-density bioreactor. The delta-sequences from the yeast retrotransposon Ty1 were used as target sites for the integration of the beta-galactosidase expression cassette. High-copy-number transformants were successfully obtained using the delta-integration sy...

Glycoside hydrolases are organized into glycoside hydrolase families (GHFs) and within this larger group, the beta-galactosidases are members of four families: 1, 2, 35, and 42. Most genes encoding GHF 42 enzymes are from prokaryotes unlikely to encounter lactose, suggesting a different substrate for these enzymes. In search of this substrate, we analyzed genes neighboring GHF 42 genes in datab...