The Effect of X-Rays on Cleavage in Arbacia Eggs: Evidence of Nuclear Control of Division Rate

Sensitization to Heat by X-Rays

“…The slow recovery observed in our experiments contrasts with the results of Henshaw (1936) on unfertilized sea urchin eggs. Henshaw found that recovery was a matter of a few hours and from the graph relating it to the time elapsed, he concluded that it was due to the removal of some toxic material from the egg by diffusion outwards.…”

Aet as a Radioprotective Agent at the Cellular Level

“…The data of the table above substantiate Henshaw (1932Henshaw ( . 1940) and Henshaw and Francis (1936), who report that a delay in fertilization of irradiated and unfertilized eggs of Arbacia allows some of them to "recover"' so that the retardation in the initial cleavage normally caused by irradiation is somewhat nullified. The percentage difference is not great, after 50,000 r exposure, but the eggs irradiated at the beginning of the series started to cleave at a shorter elapsed time interval than those irradiated at the end of the series, due to the recovery phenomenon of Henshaw.…”

Metabolic Activities and Cleavage of Eggs of the Sea Urchin, Arbacia Punctulata a Review, 1932-1949

“…X-rays Henshaw (1932Henshaw ( , 1938Henshaw ( , 1939 ; Henshaw and Francis (1936) ; Cohen ( 1939) ; ' Evans (1940) ; Evans and Beams (1939) The following agents have been found to be without effect upon cleavage of fertilized Arbacia eggs when tested at the molar concentrations shown, which were the highest concentrations employed (Clowes andKeltch, 1939-1941) : diethylmethylcarbinylurea, 8 X 10" 3 ; 4,4'-dinitrobenzophenone, 6 X 10~ 4 ; 2,4-dinitrophenylmercaptobenzothiazole, 2 X 10~ 3 ; morphine, 2 X 10~ 2 ; phenacetine, 8xlO~ H ; porphyrexide, 1 X 10~ 3 : 2-sulfanilylaminothiazole, 5 X 10~ 4 ; N-sulfanilylbenzamide, 5 X 10 4 ; sulfapyridine, 8 X 10" s ; synthalin, 2 X 10' 3 .…”