Absence of an effect of lead acetate on sperm morphology, sister chromatid exchanges or on micronuclei formation in rabbits

The influence of lead on sperm morphology, sister chromatid exchanges or on micronuclei formation was studied on male rabbits after exposure to doses of 0, 0.25, and 0.50 mg lead acetate/kg body weight subcutaneously injected three times a week during 14 weeks, each on a group of five rabbits. At the end of exposure phase the lead in blood...

The construction of new vehicles for the cloning of transcription termination signals

Chemicals/CAS: DNA Restriction Enzymes, EC 3.1.21; DNA, Recombinant; Plasmids; Tryptophan, 73-22-3

Micrococcus luteus UV-endonuclease-sensitive sites and sister-chromatid exchanges in Chinese hamster ovary cells

Chemicals/CAS: endonuclease, 9055-11-2; Endonucleases, EC 3.1.

Repair of UV-endonuclease-susceptible sites in the 7 complementation groups of xeroderma pigmentosum A through G

Chemicals/CAS: endonuclease, 9055-11-2; DNA, 9007-49-2; Pyrimidine Dimers

Escherichia coli mutant strain with altered expression of the tryptophan operon: Isolation and preliminary characterization

Chemicals/CAS: tryptophan, 6912-86-3, 73-22-3; Anthranilate Synthase, EC 4.1.3.27; Lactose, 63-42-3; RNA, Bacterial; RNA, Messenger; Tryptophan Synthase, EC 4.2.1.20; Tryptophan, 73-22-3

Mutagenicity screening: General principles and minimal criteria. Report of a committee of the European Environmental Mutagen Society

A statement of general principles and minimal criteria for the screening of chemicals for potential mutagenicity in man that may be used as guidelines for regulatory agencies and industrial organisations. To make clear the potentialities and current limitations of short-term mutagenicity testing for the prediction of genetic and carcinogenic...

Induction of mutations in bacteriophage T7 by γ rays: Independence of host repair mechanisms

Amber mutants of bacteriophage T7 are reverted by γ-rays to pseudo wild-type particles, i.e. particles able to propagate in a suppressorless host. The yield of revertants is much higher when the phage is irradiated in the presence of oxygen than when irradiated anoxically. Under particular gas conditions the efficiency of mutation induction...

A transcriptional barrier in the regulatory region of the tryptophan operon of Escherichia coli: Its role in the regulation of repressor independent RNA synthesis

Chemicals/CAS: tryptophan, 6912-86-3, 73-22-3; RNA, Bacterial; RNA, Viral; Tryptophan, 73-22-3; Tryptophan-tRNA Ligase, EC 6.1.1.2

Reversion of cistron A amber mutants of bacteriophage phiX 174 by ionizing radiation

Amber mutants of bacteriophage can be reverted by ionizing radiation to pseudo wild type particles, i.e. particles able to propagate in a suppressorless host. Since the DNA of phi X 174 is single stranded mutation cannot be due to errors in repair of radiation damage by the excision repair or by the recombination repair system of the host cell,...

Evidence for linkage of 3-phosphoglycerate kinase, hypoxanthine-guanine-phosphoribosyl transferase, and glucose 6-phosphate dehydrogenase loci in Chinese hamster cells studied by using a relationship between gene multiplicity and enzyme activity

The PGK activity was assayed in diploid, hyperdiploid, tetraploid, and hybrid cells all originating from the same Chinese hamster cell line (DON line). A relationship between gene multiplicity and enzyme activity was observed. Selective pressure on the HGPRT locus by growth of hybrid cells in the presence of 8-azaguanine resulted in decreased...

Infection of spheroplasts of Pseudomonas with DNA of bacteriophage PM2

Spheroplasts of Pseudomonas BAL-31/PM2, obtained by treatment of the bacteria with lysozyme, can be infected with purified DNA from bacteriophage PM2. After 4 h of incubation the yield of progeny phage reaches a value of 107-6×107 plaque forming units/μg PM2 DNA. The yield increases linearly with the concentration of DNA over at least 3 orders...