Localized mutagenesis of the aroE-strA section of the Escherichia coli chromosome coding for ribosomal proteins

In order to obtain E. coli strains altered in ribosomal proteins the following isolation technique was used: Phage P1 grown in a streptomycin resistant E. coli strain, was mutagenized by hydroxylamine or nitrous acid, and was used to transduce into a strain auxotrophic for aroE. Transductants with streptomycin resistance and aroE prototrophy were selected and tested for their growth at various temperatures (20 degrees, 30 degrees and 42 degrees) and their response to different antibiotics. Ribosomes from seventeen transductants with an altered response to temperature or antibiotics were isolated. They were tested for alterations in their ribosomal subunit profiles by sucrose centrifugation and for altered ribosomal proteins by two dimensional gel electrophoresis. Two strains showed accumulation of 50S ribosomal precursors and three strains had an altered 50S protein L18. This protein belongs to the 5S RNA-protein complex having GTPase and ATPase activity.

Pulmonary aspergillosis in childhood. A case report and discussion

An adolescent girl with aspergillosis is presented who demonstrated three different manifestations of the disease process. Therapy included the use of Amphotericin B and two pulmonary resections for aspergillosis. The patient has been stable for one and a half years without any evidence of recurrent disease, after a progressive course going back for some years.