36
TUNEO
YAMADA
Furthermore, the non-neural differentiation consisted, according to Niu,
of three components of quite different natures. Under these circumstances, the question arises whether the non-neural component obtained
in the RNA-series or soy bean inhibitor-RNA series is actually capable
of forming the thymus-like body in the larva. This decisive point is not
discussed in the paper.
TABLE V
Inductive Effects of Thymus RNA Solutions on Isolated Ectoderm of the
Triturus Gastrula
Series
Total No.
Explants with Induction
Series
of Explants
No.
Nature of Induction
RNA (25 jig/ml)
(nylon)
24
1
archencephalic
RNA (50 /xg/ml)
(nylon)
14
1
archencephalic
RNA (50 /xg/ml)
(nylon-less)
14
0
Albumin (150 /xg/ml)
(nylon)
7
0
Albumin (150 /xg/ml)
(nylon-less)
12
1
non-regional neural
RNA (50 /xg/ml)
+ Albumin (150 /xg/ml)
(nylon)
32
1
non-regional neural
RNA (150 /xg/ml)
+ Albumin (150 jxg/ml)
33
0
The experiment has been repeated in our laboratory, because of its
great importance (Yamada and Osawa, unpublished work). The nylon
technique (Section IV) was adopted, which enabled an easy identification
of induced tissues belonging to all germ layers, as illustrated in Figs. 5, 7,
8, 9, 10, 11, 12, 14. The RNA sample was prepared from calf thymus
according to the technique employed by Niu, and was tested immediately
after preparation at concentrations of 50 /¿g/ml and 25 /xg/ml, with or
without addition of human serum albumin whose possible effect was
tested alone. The results were negative in all the series, the majority of