[Sterilization of non-air evacuated infusion flasks containing little water].

Studies have been carried out in connection with the sterilization of glass infusion bottles from which air had not been evacuated and containing certain limited quantities of water. Bottles with a capacity of 500 and 1000 cm3 were filled with 1-3 cm3 distilled water and sterilized in an autoclave for 20 min. set at a temperature of 121 degrees C reaching up to 126 degrees C.

Reversion of nonsense mutants induced by 4-nitroquinoline-1-oxide in Schizosaccharomyces pombe.

We have studied the reversion of 8 nonsense alleles located in 7 different genes of Schizosaccharomyces pombe using 4-nitroquinoline-1-oxide (NQO) as a mutagenic agent. The nonsense mutants of S. pombe have been classified according to their suppressibility by defined opal and ochre suppressors into a class of efficiently suppressed opal and a class of inefficiency suppressed ochre mutants.

[Diphtheria epidemic in eastern Switzerland in 1974].

A diphtheria epidemic in the eastern part of Switzerland in 1974 and the measures which were taken for its management and eradication are described. In particular it is pointed out that at present diphtheria displays atypical clinical symptoms in Europe, a fact that renders the diagnosis very difficult in many cases. Therefore, it is important to perform a throat swab in every patient with suspected diphtheria; it is also necessary to explicitly require a search for C.

Mutator activity of petite strains of Saccharomyces cerevisiae.

Petite strains in Saccharomyces exhibit enhanced spontaneous mutation rates of nuclear genes regardless of whether they are cytoplasmically or nuclearly inherited, or whether or not the cytoplasmic petite strains have mitochondrial DNA. In petite strains, the mutation rate for the nonsense allele lys1-1 is enhanced by a factor of 3-6 and for the missense allele his1-7 by a factor of 2 as compared with their grande counterparts. The reversion of a third allele, the putative frameshift mutation, hom3-10, is not enhanced in a petite background.