PR-8-93 Chalk River, Ontario AEGL-4213 ATOMIC ENERGY OF CANADA LIMITED Chalk River Nuclear Laboratories PROGRESS REPORT January 1 to March 31, 1972 Biology and Health Physics Division PR-B-93 Chalk River, Ontario June 1972 AECL-4213 PROGRESS REPORT January 1 to March 31, 1972 Biology and Health Physics Division Director - Dr. A.M. Marko Scientific Administrative Officer* Secretary - Mrs. B.L. Phillips Staff reporting to Divisional Office . - Mr. M.I. Gibson Mr. L.G. Hunter CONTENTS 1. Summary - Dr. A.M. Marko 1 - 5 Z. Biology Branch - Dr. A.M. Marko 7-23 3. Population Research Branch - Dr. H.B. Newcombe 25-28 4. Environmental Research Branch - Dr. C.A. Mawson 29-41 5. Health Physics Branch - Mr. G. Cowper 43-63 * Administrative assistance provided by F.P. Blackstein of Physics Division BIOLOGY AND HEALTH PHYSICS DIVISION SUMMARY A.M. MARKO Biology Considerable progress has been achieved in all the current projects in the Biology Branch. At the molecular level, a method for establishing the order of certain genes in RNA molecules has been made possible by the purification of an enzyme which degrades RNA from one end only. Studies with E_^ coli have been concerned with measurement of the breakdown of DNA membrane complex following irradiation under different conditions. Two chemical compounds, which are known to interfere -with the function of the cell membrane, also increase the num- ber of breaks in the irradiated DNA. In the bacterium M_. radiodurans, the detailed chemical reactions of two enzymes to digest damaged DNA has been -worked out; these enzymes are believed to be involved in repair processes. Another enzyme, DNA polymerase from M. radiodurans, which repairs the defect in the damaged part of the DNA molecule has been further characterized by finding what chemical agents can inhibit its activity. In the yeast. S_. pombe, the inhibition of repair by caffeine hat. been used in the study of recovery from uv- and y-radiation. The results show that repair requires a complete growth medium and is dependent on temperature. The effects of chemical mutagens on yeast -2- have proved that replicating instabilities are common, and yeast cells can mutate to stable phenotypes or replicate as a mutant,which continues to be genetically unstable. In bacteriophage, gene mapping has indicated the region on the DNA responsible for "superinfection exclusion", a pro- cess which occurs when bacteria are reinfected with phage, and results in the exclusion of the second phage among the progeny. Mutants induced in phage by chemicals, by uv-> and by ionizing radiation, have been screened for their ability to exclude superinfecting phage. In the wasp Dahlbominus, the irradiation of carmine eye colour mutants has shown that reversion to the wild phenotype is possible, This is a good indication that the eye colour mutants do not arise as a result of chromosome rearrangements or deletions but as true point mutations. Leukemia in rats has b^en chemically induced, and the charac- teristics of the disease have been shown to be comparable to that found in irradiated animals. Population Research Analyses of data from the experiments with irradiated trout sperm, carried out at Jasper, have now revealed a mixture of "harmful" and "beneficial" effects of the lower doses used (i.e. 25 and 50 rad). Although such exposures produce congenital malformations, they also lower the likelihood that eggs will fail to develop embryos, and the like- lihood of death among the embryos that are formed. Higher dose to the -3- sperm (of 200 and 400 rad) have unconditionally harmful effects with respect to all three end points. Work is continuing on the production of indexes of British Columbia births, in a multiplicity of sequences, designed to facilitate integration of diagnostic information on congenital and hereditary disease from handicap, hospital, and death records, into individual and family histories of disease. As part of a pilot study of cancer following multiple fluoroscopy, designed initially at CRNL and now being carried out by the National Cancer Institute, a phantom has been constructed and sent to NCI for the purpose of measuring the dose-depth curve for two old fluoroscope machines that are still in intermittent use at Toronto Hospital Weston. Dosimeters are being provided by the Health Physics Branch at CRNL. Environmental Research Discharges of radioactive wastes into the environment via the stack and effluent streams entering the Ottawa River have remained within the CRNL Working Limits, which are far below the recognized Safety Limits. Discharges to the river continue to be a small fraction of the fission products carried by the river, originating from weapons fallout, Analytical work on environmental samples collected during the -4- Spring and Summer of 1971 continued throughout the quarter and will shortly be completed. Winter work on aquatic biology beneath ice cover was carried out at Maskinonge and Perch Lakes and preparations were made for the installation of summer meteorological equipment at Ferch Lake. Water and mineral balance studies in the Perch Lake Basin continued, and the number of elements studied in the leaching survey has been increased with the acquisition of new equipment and elaboration of improved techniques. Contract work by the Trois Rivieres Campus of the Universite du Quebec on the effects of discharge of heated effluent by the Gentilly nuclear power station proceeded successfully. Good liaison between the Branch and University staff is producing a pleasing unity of interests and excellent personal collaboration. Health Physics Certain monitoring procedures for contamination control require large area radiation detectors and this requirement has hitherto been met by the use of thin plastic scintillators and photo-multipliers which are both expensive and bulky. An attractive alternative detector now available from a commercial source is a 23 mg/cm^ window GM counter having a sensitive area of 250 cm2. The application of this counter to hand, foot and clothing monitoring is now being examined. -5- Manufacture of the automatic thermoluminescence dosimeter (TLD) reader is proceeding in industry and large-scale field trials of dosi- meters are continuing with 150 workers being monitored. TLD's have also been used to determine diagnostic doses received by patients in the CRNL hospital. The development of techniques for monitoring of tritium in air and water continues. A more rugged detector assembly capable of with- standing accidental over-pressures has been developed for the plastic scintillator plate water-monitor, and at the same time the feasibility of continuous monitoring using a liquid scintillator at very low flow rates (for reasons of economy) is being examined. With a consumption of only 100 litres of scintillator per year, it appears possible to monitor tritium- in-water levels as low as 100 nCi/litre. The modified tritium-in-air ion chambers, which compensate both for gaseous fission product and external gamma radiations, are in satisfactory operation at Douglas Point. An area monitor capable of operation in pulsed high energy radiation fields from accelerators as well as fields from radioactive sources is being developed using a plastic scintillator and photomultiplier whose mean current will be processed to give digital outputs of both do.se rates and integral doses. -7- BIOLOGY by A. M. Marko, Acting Branch Head CONTENTS 2. 1 Staff (1 January to 31 March 197 2) BIOCHEMISTRY AND MOLECULAR BIOLOGY 2. 2 Comparison of RNA Molecules in Animal Cells by Oligo- nucleotide Analysis 2. 3 Study of Rapidly Sedimenting, Heterogeneous RNA in Animal and Yeast Cells 2. 4 Search for Genes Corresponding to Poly A Sequences Found in Messenger and Heterogeneous Nuclear RNA 2. 5 Radiation Biochemistry of E. coli a) DNA membrane association b) Radiation sensitizing agents 2. 6 Protection of Rat Thymus Cells 2. 7 Induction of Leukaemia in Rats 2. 8 Nucleases of M. radiodurans a) 5 -nucleases b) Exonucleases 2. 9 Repair of Radiation Damage in Bacteria and Yeast a) The DNA polymerase from Micrococcus rad_io_- durans b) Recovery of S. pombe from radiation damage -8- GENETICS, DEVELOPMENT AND POPULATION STUDIES 2. 10 Genetic Control of Radiation Sensitivity in Schizosaccharo- myces pombe 2. 11 Replicating Instabilities In Schizosaccharomyces pombe 2. 12 Liquid Holding Recovery and Spontaneous Cell Death in the Normal and Radiation-sensitive Strains of Schizosaccharomyces pombe a) Modification of radiation-induced mutational damage b) Differentiation between dead and inactivated cells 2. 13 The Effect of Dark Repair Inhibitors On the Growth of Irradiated S. pombe Cells 2. 14 Super infect ion Exclusion by Bacteriophage T4 2- 15 Polyacrylamide Gel Electrophoresis of Bacteriophage T4 2. 16 Radiation Genetics in Insects - Dahlbominus 2. 17 Radiation Injury - Rhodnius 2. 18 Radiation Studies on Biting Flies 2. 19 PUBLICATIONS -9- 2.1 STAFF Acting Branch Head - A.M. Marko BIOCHEMISTRY AND MOLECULAR BIOLOGY RNA Molecules H.C. Birnboim Assistants B.V. Coakley (Miss) M.D.B. Cecil (Mrs.) Radiation Biochemistry D.K. Myers Assistant L.D. Johnson K. G. Chetty Repair of DNA. in Bacteria R.E.J. Mitchel Assistant K.M. Baird Enzymatic Repair of Radiation Damage N.E. Gentner Assistant M.M. Werner (Mrs.) GENETICS, DEVELOPMENT AND POPULATION STUDIES Radiation Repair in Insects W.F. Baldwin Assistants G.D. Chant P. A. Knight A.G. Knight Microbial Genetics A. Nasim Assistants C.E. Grant (Miss) B.P. Smith M.M. Shahin Bacteriophage T4 Genetics J. D. Childs Assistant L, A. Chant (Mrs. ) Secretarial - M. E. Swallow (Mrs. ) Biological attendants - 2 -10- 2. 1 continued Attached Staff M. M. Shahin, an NRC Postdoctoral fellow, is working with A Nasim. K. G. Chetty, a trainee under the Colombo Plan, is working with D. K. Myers. 2. 2 COMPARISON OF RNA MOLECULES OF ANIMAL CELLS BY OLIGONUC LEO TIDE ANALYSIS - H. C. Birnboim and B.