Biochemical properties of a penicillinase from Escherichia coli carrying Rms 298.

We obtained two R plasmids, i.e., Rms195 and Rms298, from a clinical isolate, E. coli GN5503. Penicillin beta-lactamase (PCase) was extracted from ML1410 Rms195+ and Rms298+, and was purified by chromatography. Rms195 PCase was identical to the type I PCase mediated by R-TEM, RI and Rms212. The isoelectric point of Rms298 PCase was 5.9 and its molecular weight was 21,000 +/- 1,000. The substrate profile and physiochemical properties indicate that Rms298 PCase belongs to the type IV PCase mediated by Rms139 isolated from Pseudomonas aeruginosa.     

Transfer Agent of Immunity

An immune ribonucleic acid (RNA) preparation was extracted with phenol from the spleens of guinea pigs immunized with diphtheria toxoid. Antibody-carrying cells were detected by immunocyte adhesion as rosette-forming cells. When germ-free rats, conventional guinea pigs or mice were injected intraperitoneally with this preparation, the rosette-formers were detected in either peritoneal exudate cells or spleen cells, whereas serum antibodies were unable to be detected thus far in such animals. Two injections with this preparation did not cause any remarkable increase in the number of rosette-formers, and serum antibody was also not detectable. By contrast, a high titer of serum antibody was demonstrated and the number of rosette-formers increased shortly after an injection of a small amount of diphtheria toxoid into guinea pigs which had previously received an injection with immune RNA. This reaction indicates a secondary response of antibody formation. However, secondary responses were not induced by injections of immune RNA preparations in guinea pigs primed with either diphtheria toxoid or immune RNA preparation. These facts suggest that immune RNA preparations did not contain antigens or fragments thereof and the immune response induced by RNA preparation is not the same as that induced by stimulation by the antigen itself. These results moreover can be accounted for by the notion that the immune RNA preparation is able to induce “memory” cells capable of responding to a secondary stimulus with an antigen and producing a high titer of serum antibody.     

Further Evidence for Inactivation of Fructose-1,6-bisphosphatase at the Beginning of SO2 Fumigation. Increase in Fructose-1,6-bisphosphate and Decrease in Fructose-6-phosphate in SO2-Fumigated Spinach Leaves

The substrate level of the photosynthetic reductive pentosephosphate cycle in spinach leaves during SO₂ fumigation wassurveyed. At the beginning of SO₂ fumigation, fructose-1,6-bisphosphateincreased and fructose-6-phosphate decreased, while ribulose-1,5-bisphosphateremained unchanged and 3-phosphoglyceric acid rapidly decreased.These results suggested that the inhibition of photosynthesisin spinach leaves with SO₂ might be due to inactivation of fructose-1,6-bisphosphatase. (Received May 26, 1982; Accepted September 27, 1982)     

Purine metabolic enzymes in lymphocytes. II. Adenosine deaminase and purine nucleoside phosphorylase activities in the immune response

ICR mice were immunized with sheep red blood cells (sRBC). Both adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in spleen lymphocytes increased faster than the serum antibody titer and reached a peak one week after the immunization. ADA activity increased significantly in T lymphocytes but not in B lymphocytes collected from the spleens of the immunized mice. A statistically significant increase in PNP activity was found in both T and B lymphocytes from the spleens of the immunized mice. Spleen lymphocytes collected from ICR mice which had been immunized with mitomycin C-treated sarcoma 180 (S180) cells one week earlier showed cytotoxic activity against viable S180 cells. Both ADA and PNP activities in spleen lymphocytes of S180-immunized mice increased significantly, and both activities increased in T lymphocytes prepared from spleen of immunized mice. In contrast, an increase was found in PNP activity but not in ADA activity in B lymphocytes. These results suggest that an increase in both ADA and PNP activities may by necessary for the T-cell response in both humoral and cellular immune responses, and that an increase in PNP activity may be necessary for the B-cell response.     

Purification and Properties of Dihydrostreptomyein-Phosphorylating Enzyme from Pseudomonas aeruginosa

The distribution of the dihydrostreptomycin (DHSM)-phosphorylating enzyme was investigated using DHSM-resistant strains of Pseudomonas aeruginosa, indicating that this enzyme was demonstrated from all of 7 DHSM-resistant strains examined but not from a DHSM-sensitive one. The DHSM-phosphorylating enzyme was isolated from P. aeruginosa TI-13 and purified about 205-fold using Sephadex G-75 and DEAE-Sephadex A-50 column chromatography. The optimal pH for the DHSM-inactivation was around 10.0, and both adenosinetriphosphate (ATP) and Mg⁺⁺ were required for the inactivating reaction. It was found that this enzyme inactivated only DHSM but not other aminoglycosidic antibiotics such as kanamycin, aminodeoxykanamycin, neomycin, paromomycin, lividomycin and gentamicin.