TMtative Proposal5

Cytogenetic effect5 of radiations on bacteria

De~;arta~ent ef baotice; Univeroity oE Misomsin; ?hdison, Ji.8.

~Ofihu& baderberg (Ao~ociate Profeubor of &meticfl)

    Support ie retpsfi'frm the Atomic Energy Omfesfon for tho

gwe?imirury cqlorction of e subject which may throw fundamatal. X&t

cm the mechanism of biological action of ionizing radiations. The F&orial

to he studied ie diploid oells of $eohrriohia oolt. Work in progress har

shown that this material tan be u130d to test the a&@MSaance of raceesive

lethal mutations in the bacteriaida effeote of chemical mMagena euch

as nitrogen mustard or physical a?ente suoh as u?tra-violet li$d. In

diplo3.d cells, lethal mutations can be detected owing to their t,emForc,ry

masking by the unmutaZsd gymme; 3.n haploid celln, of aourae, I.eth5.1 mutations

result in cell death, and are thus not amenable to study.

     Work in progress indicate5 that, oontrary to sxpectition, I&ha1

mutatf.one ploy an inslgnlf'ican& role in bacterial k3JUng by nitro,o;en mustard

or ultraviolet light. BacMrioide by these, and a IarE number of other

nmnbs, inelud%ng hydrogm peroxide, formaldehyde, a?d X-raye (in R single
.2

prellalnary experimmt) is,hrrrwevsr,cummpM.d by 05mplex ganetfn rsor~~nizationa,

not c@mpleteXy understood as y&, but inaluding the produotion of cell5 with

bqloid, rathsr than diploid constitution. 18 i5 alao apparent that these

&.n@s are accompanied by dierfurbamee in the divbim snd dlstrf.bution of

tbo nuclear bodies in the treated bacteria.

     `i%8 present prajeot oanaerna the extension of tM.6 gonetic and o+

lagioal work with speoial refenenw to the effects of X-rays (and subsequently,

of other ionizing radiations). Beoause the projaot is already under way to

some extent, with reeipeot to abemkcal azi ulti+vlcllet effocta, a mdest re-

quest bs made for the first year, as 421s m!or him of t?m project during this


support prior to f&a sxpPration of this tmm. The probable tern of an extended

project would be abmt four y?sara 9 UT&B~ full-the eqlopsc diraplaae


mar graduate sttionts.