160
F.
Ε.
LEHMANN
(3) A substance with unknown biochemical activity:
Glucosamine
(4) A highly active inhibitor of cell movements and cell division:
Colchicine (Lehmann, 1957b)
(5) Several very reactive substances:
E.g. Quiñones, iminoquinones (Marxer, 1955; cf. also Petersen et al.,
1955).
See our earlier statement (1942) that quiñones and hydroquinones are
powerful antimitotic substances in the cell division of Tubifex eggs.
2. Technique of Regeneration Experiments with Xenopus Tadpoles
The experimental methods have been those published by Lehmann
and Bretscher (1952). In the experiments with combined solutions of morphostatic substances we followed the technical procedures as described
by Lehmann (1957a). The regenerating tadpoles were maintained for
10 days at a temperature of 18° C in the solutions to be tested. At the
end of 10 days the controls had regenerated the amputated tail tip to
a great extent (see Fig. 1(a)). This can be compared with the reduced
regeneration occurring in the vessels containing inhibitory substances
(Fig. 1(6)). Each vessel contained 5 animals.
For our final experiments only inhibitory solutions which produced a
degree of inhibition of 90-100% were tested. The mean values of the
controls served as a base for comparison. The relative degree of regenerate inhibition in controls was considered to be 0% (Fig. 1(a)) and
the totally inhibited larvae as showing a degree of 100% (Fig. 1(6)).
Only experimental series in which all animals survived and at least 3
out of 5 showed total suppression of regeneration were taken into
account. We express the proportion between the number totally
inhibited and the number of experimental animals by a quotient: a
value of 0-6, 0-8 or 1 means 3, 4 or 5 totally inhibited out of 5 experimental individuals.
Tables I and II show that several combinations may produce an
inhibition of up to 100% i.e. a quotient of 1. These results designated as
'total suppression of regeneration' without lethality fulfil rather exacting
requirements.
3. Selective Suppression of Regeneration
In our experiments we find two groups with totally suppressed
regenerates. In the first group the inhibitory effect of one of the paired
substances is already rather high and the other substance produces only
a small supplementary effect. This is the case in the following combinations (see Tables I and II): quinoxaline-colchicine, quinoxaline-tyrosinol,
colchicine-histidinol, colchicine-glucosamine.
F.
Ε.
LEHMANN
(3) A substance with unknown biochemical activity:
Glucosamine
(4) A highly active inhibitor of cell movements and cell division:
Colchicine (Lehmann, 1957b)
(5) Several very reactive substances:
E.g. Quiñones, iminoquinones (Marxer, 1955; cf. also Petersen et al.,
1955).
See our earlier statement (1942) that quiñones and hydroquinones are
powerful antimitotic substances in the cell division of Tubifex eggs.
2. Technique of Regeneration Experiments with Xenopus Tadpoles
The experimental methods have been those published by Lehmann
and Bretscher (1952). In the experiments with combined solutions of morphostatic substances we followed the technical procedures as described
by Lehmann (1957a). The regenerating tadpoles were maintained for
10 days at a temperature of 18° C in the solutions to be tested. At the
end of 10 days the controls had regenerated the amputated tail tip to
a great extent (see Fig. 1(a)). This can be compared with the reduced
regeneration occurring in the vessels containing inhibitory substances
(Fig. 1(6)). Each vessel contained 5 animals.
For our final experiments only inhibitory solutions which produced a
degree of inhibition of 90-100% were tested. The mean values of the
controls served as a base for comparison. The relative degree of regenerate inhibition in controls was considered to be 0% (Fig. 1(a)) and
the totally inhibited larvae as showing a degree of 100% (Fig. 1(6)).
Only experimental series in which all animals survived and at least 3
out of 5 showed total suppression of regeneration were taken into
account. We express the proportion between the number totally
inhibited and the number of experimental animals by a quotient: a
value of 0-6, 0-8 or 1 means 3, 4 or 5 totally inhibited out of 5 experimental individuals.
Tables I and II show that several combinations may produce an
inhibition of up to 100% i.e. a quotient of 1. These results designated as
'total suppression of regeneration' without lethality fulfil rather exacting
requirements.
3. Selective Suppression of Regeneration
In our experiments we find two groups with totally suppressed
regenerates. In the first group the inhibitory effect of one of the paired
substances is already rather high and the other substance produces only
a small supplementary effect. This is the case in the following combinations (see Tables I and II): quinoxaline-colchicine, quinoxaline-tyrosinol,
colchicine-histidinol, colchicine-glucosamine.