Inhibition of messenger ribonucleic acid synthesis in Escherichia coli by thiolutin

Thiolutin, at concentrations of 5 to 40 mug/ml, inhibited the induced synthesis of beta-galactosidase in Escherichia coli CA8000. Thiolutin had no effect on the rate of in vitro hydrolysis of o-nitrophenyl-beta-d-galactoside by purified beta-galactosidase. Examination of the effects of thiolutin on the kinetics of appearance of beta-galactosidase in the presence and absence of rifampin in induced E. coli cells indicated that thiolutin interferes with the transcription process at the level of elongation of messenger ribonucleic acid (mRNA) chains. The data indicated that, in the presence of thiolutin, beta-galactosidase mRNA has a half-life of 1.6 min and that the first completed beta-galactosidase mRNA is produced about 1.5 min after induction. These data are consistent with estimates of transcription time and messenger half-life obtained by conventional means, and suggest that thiolutin does not affect translation of mRNA or its breakdown in vivo. After removal of thiolutin, cells fully regained the ability to be induced for synthesis of beta-galactosidase within 10 min, but mRNA which was incomplete at the time of thiolutin addition did not subsequently become functional.

Golgi beta-glucuronidase of androgen-stimulated mouse kidney

Subcellular fractions were prepared from mouse kidney homogenates by differential and sucrose-gradient centrifugation. A fraction enriched in Golgi apparatus was obtained, which had considerably enriched galactosyltransferase and thiamin pyrophosphatase activities, and was morphologically typical of Golgi material. This preparation also had high beta-glucuronidase activity, which increased concomitantly with microsomal beta-glucuronidase activity during the specific stimulation of the enzyme in male mouse kidney after androgen administration. The degree of stimulation was much greater in the Golgi fraction. Gel-electrophoretic patterns of Golgi beta-glucuronidase resembled more closely those of the enzyme located within lysosomes, but contained minor bands similar to those described previously (Swank & Paigen, 1973) as characteristic of the microsomal enzyme. It was concluded that the Golgi complex is involved in the distribution of the enzyme after its synthesis to both lysosomal and microsomal fractions.

Surface polysaccharide from Staphylococcus aureus M that contains taurine, D-aminogalacturonic acid, and D-fucosamine

The surface polysaccharide antigen of Staphylococcus aureus M was isolated, and the component parts were identified. The antigen is composed of taurine, d-aminogalacturonic acid, and d-fucosamine. The capsule is chemically distinct from all previously reported staphylococcal capsules. Taurine and aminogalacturonic acid have not been reported previously in staphylococci.