The effect of rifampicin on the stability of the messenger ribonucleic acid of Bacillus amyloliquefaciens as determined by DNA:RNA hybridization

Rifampicin at a concentration of 10 mug/ml completely inhibited protein synthesis in exponential-phase cultures of Bacillus amyloliquefaciens. At this same concentration the drug was shown to have no effect on the stability of mRNA, determined as the functional and hybridizable material, when compared with hybridizable mRNA in an uninhibited system. In each case, the half-life of the mRNA had a value in the range 5 +/- 1 min, at 30 degrees C.

Cytoskeletal elements of chick embryo fibroblasts revealed by detergent extraction

Treatment of chick embryo fibroblasts with 0.5% Triton X-100 extracts most of the cell protein, leaving an organized part of the cell structure attached to the tissue culture dish. This "Triton cytoskeleton" consists largely of intermediate-sized filaments and bundles of microfilaments. SDS polyacrylamide gel electrophoresis reveals that this cytoskeleton is made up of three main proteins. One protein component is 42,000 daltons and co-migrates with muscle actin. The other two components are 52,000 and 230,000 daltons and remain quantitatively associated with the cytoskeleton during the detergent extraction. The possible identity of these three protein components and their organization into a supramolecular structure is discussed.

The use of a written summary in group psychotherapy supervision

Clinical supervision is an important feature of the education of the group therapist. The authors describe the application of a summary written by trainee cotherapists in their supervision. They found that the summary, which is supplied to the patients as well as to the supervisor, serves several functions that contribute to improved quality of clinical supervision and training of group therapists.

Relationship between exoprotease secretion and the synthesis of ribonucleic acid and protein in Bacillus amyloliquefaciens

Studies with washed bacteria suspended in fresh medium, in which bacterial densities were altered by a factor of four so as to cause accelerated entry of exponential bacteria into the postexponential phase and to re-establish growth in postexponential bacteria, have been performed. Under all the conditions examined rifampin, at a concentration of 0.5 mug/ml, inhibited [(14)C]uracil incorporation into total ribonucleic acid (RNA) by 90 to 95%. The percentage of inhibition of incorporation of (14)C-labeled amino acids into total protein achieved in parallel experiments was less, being not more than 80%. These results suggested that non-translatable RNA synthesis was inhibited more than messenger RNA (mRNA) by the antibiotic. It was found that on slowing the growth of exponential-phase bacteria exoprotease was formed at a high rate without a lag. It was further observed that when postexponential bacteria were induced to grow, by resuspending them at a lower density, exoprotease mRNA synthesis was switched off. The only synthesis of exoprotease which occurred in this case was accountable to pre-existing mRNA during its decay. Exoenzyme formation was found to be less susceptible to rifampin than total protein synthesis.

The written summary as a group psychotherapy technique

During the past 18 months, we have been preparing detailed written summaries of the events of group therapy meetings, which have then been mailed to the group members. This technique was introduced initially as a device to provide structure in a very anxious group. We soon realized that the summary had a great potential for enhancing therapist effectiveness and it came to assume a number of other functions. In this report, we describe our experience with this technique, emphasizing its importance as a tool to improve the cognitive integration of the group therapy experience for both patient and therapist.

Reagin synthesis in inbred strains of rats

Reaginic antibody synthesis after intraperitoneal immunization with ovalbumin in aluminium hydroxide gel (Al(OH)₃) has been evaluated in BN, F344 and ACI inbred strains of rats and compared to that in outbred Wistar rats. Regardless of the dose of antigen employed (0.1 mg, 0.01 mg, 0.001 mg), BN inbred and Wistar outbred rats produced comparable amounts of reaginic antibody 9 days after immunization and these reagins were detectable for at least 70 days. In addition mean serum reagin titres could be boosted by subsequent administration of antigen. There was no statistically significant difference in the response of males as compared to females. The use of Al(OH)₃ gel as an adjuvant yielded reaginic antibody titres in these animals that were comparable to those induced with antigen administered with saline extracts of Bordetella pertussis organisms. In contrast ACI inbred rats failed to generate detectable reaginic antibodies when immunized either singly or repetitively with the same doses of antigen in Al(OH)₃ gel as used in the BN and Wistar rats. Wistar, BN, and ACI strains produced IgGa-like antibodies after a single immunization; however, peak serum titres were somewhat greater in the Wistar and BN, as compared to the ACI strain. Haemagglutinating antibody titres were comparable and greater than 1:1000 in all the strains studied within 35 days after immunization. These studies have demonstrated another animal model to explore the genetic mechanisms involved in the synthesis of reaginic antibody.