Bacteriophage P2-lambda interference: II. Effects on the host under the control of lambda genes O and P

Induction of bacteriophage lambda in the presence of a P2 prophage causes a drastic inhibition of protein synthesis through transfer RNA inactivation, and then a shut-off of uridine incorporation. It has also been found to trigger a peculiar process of host killing.We have investigated the dependence of these effects with respect to the genetic determinants of interference. We have shown, moreover, that genes O and P, which control the initiation of phage replication, are required for P2-λ interference. The way the host tRNA can be inactivated through the expression of those genes, which are all concerned with DNA metabolism, is discussed.     

Electron microscopy study of non-precipitating anti-dinitrophenyl antibodies

Non-precipitating anti-dinitrophenyl pig immunoglobulins G have been studied by negative staining, freeze-drying and high-resolution shadow casting. The general morphology of the molecules is described. The predominant conformation of antibody molecules is a tripod-like one.     

Outcomes after Chemotherapy with WHO Category II Regimen in a Population with High Prevalence of Drug Resistant Tuberculosis

Standard short course chemotherapy is recommended by the World Health Organization to control tuberculosis worldwide. However, in settings with high drug resistance, first line standard regimens are linked with high treatment failure. We evaluated treatment outcomes after standardized chemotherapy with the WHO recommended category II retreatment regimen in a prison with a high prevalence of drug resistant tuberculosis (TB). A cohort of 233 culture positive TB patients was followed through smear microscopy, culture, drug susceptibility testing and DNA fingerprinting at baseline, after 3 months and at the end of treatment. Overall 172 patients (74%) became culture negative, while 43 (18%) remained positive at the end of treatment. Among those 43 cases, 58% of failures were determined to be due to treatment with an inadequate drug regimen and 42% to either an initial mixed infection or re-infection while under treatment. Overall, drug resistance amplification during treatment occurred in 3.4% of the patient cohort. This study demonstrates that treatment failure is linked to initial drug resistance, that amplification of drug resistance occurs, and that mixed infection and re-infection during standard treatment contribute to treatment failure in confined settings with high prevalence of drug resistance.