150 J. R. SIMMONS AND H. K. MITCHELL 
with time. It is also noteworthy that even over a period of 140 min, during which the 
larvae were not fed, there was not a great loss in the total amount of radioactivity 
present. 
Valine incorporation. The results given in Table III and Fig. 3 are representative of 
those found in five injection experiments using ['C] valine. At no point during the 
time series was it possible to distinguish distinct peaks of radioactivity other than at 
1000 
N 
Ol 
Oo 
Counts/min 
Oo 
oO 
oO 
° 3 D j 
Fig. 3. Distribution of radioactivity resulting from the paper chromatography of squashed whole 
animals injected with [14C] valine (10j#C/201). Numbers indicate areas measured by the planimeter 
with 1 being the chromatographic origin and 3 most closely matching the position of known valine. 
the origin and in the chromatographic position of valine. There was, however, a 
continuous zone of radioactivity between these two points. Though the results of the 
particular experiment recorded in Table III would seem to indicate considerable loss 
of radioactivity at the end of 60 min. it is felt that this is not the case. In other ex- 
periments with valine there was nearly as much total radioactivity remaining at 
60 min as was found at earlier times in the series. It is most likely that the difference 
is attributable to variation in the amount initially injected in this particular experi- 
ment. 
On elution and hydrolysis of the material from the area between the origin and 
TABLE III 
VALINE INCORPORATION 
84-h larvae were injected with a solution of 10 wC/20 wl of L-valine 
and three larvae were squashed on Whatman No. 1 paper at the time 
from injection indicated. After chromatography in the propanol,NH, 
solvent the chromatograms were scanned with the strip counter and 
the areas determined by planimetry. Radioactivity is reported as the 
per cent of total radioactivity present. Areas refer to those designated 



in Fig. 3. 
Time Total % of total radioactivity at area 
(min) area a b 3 
1.5 2.554 1.0 5.3 93.3 
3 1.874 10.5 10.6 78.8 
5 1.873 16.5 10.1 73-3 
IO 2.159 14.5 9.3 79.4 
15 1.70 30.4 7.6 62.0 
30 1.797 35-4 10.4 54.1 
60 1.221 54.1 14.7 31.0 

References p. 155 
