160
R. LALLIER
changes during development. According to Lindahl, the constant part
of the respiration would be related to the utilization of the lipids while
the increasing part would be related to the oxidation of the glucides.
Results obtained by Öhman do not contradict this idea, but they need
to be completed by estimation of the different substrates during
development in order to demonstrate their utilization.
Lindahl and Holter (1940) applied the extremely sensitive diver
method of Linderstr0m-Lang to the measurement of oxygen consumption of isolated animal and vegetal halves. They observed that both
halves use the same quantity of oxygen and that respiration increased
in the same proportion in the animal and vegetal halves during segmentation. Lastly, the sum of the quantities of oxygen used by the two
halves is equal to the quantity used by the entire egg. These observations
do not appear to favour the existence of a respiratory animal-vegetal
gradient. Nevertheless, we must notice that the isolation of animal and
vegetal halves, suppressing their mutual interactions, creates new
conditions, different from those existing in the entire egg, and that these
new conditions are liable to influence the consumption of oxygen.
Lindahl and Holter have completed these researches by studying the
effect of lithium, and of some other inhibitors of respiration, on isolated
animal and vegetal halves. Lithium inhibits the respiration of isolated
animal or vegetal halves in the same proportion. The same result is
obtained with cyanide and DL-glyceraldehyde. From all these results it
follows that the increase of respiration is not peculiar to the animal
halves, and that this function has the same sensitivity to the inhibitory
effects of lithium in animal and in vegetal halves.
Inhibitors of respiration have been studied in the whole egg and their
effects compared to those of lithium. Cyanide, carbon monoxide and
anaerobiosis partly inhibit oxidation and increase the vegetalizing
effects of lithium. If used alone, cyanide, carbon monoxide and anaerobiosis are not very effective. Carbon monoxide is the only one liable to
strengthen the vegetalization of isolated vegetal halves. Moreover, it is
also able to increase the animalization of isolated animal halves
(Runnström, 1928b; Hörstadius and Strömberg, 1940). The effect of
these agents can be attributed to an indirect action on metabolism, for
instance to the formation of an acid. In fact Lindhal (1940) has shown
that some organic acids, such as lactic, acetic and formic acids, strengthen
the vegetalizing action of lithium. This effect is also produced by bases
such as diethylamine (Lindahl, 1940), nicotine and guanidine (Lallier,
unpublished work). Thus it appears that the inhibitors of respiration do
not have vegetalizing effects comparable to those observed with lithium.
Let us now examine carbohydrate metabolism. In the sea urchin egg,
two pathways of carbohydrate breakdown have been identified (Fig. 10).
R. LALLIER
changes during development. According to Lindahl, the constant part
of the respiration would be related to the utilization of the lipids while
the increasing part would be related to the oxidation of the glucides.
Results obtained by Öhman do not contradict this idea, but they need
to be completed by estimation of the different substrates during
development in order to demonstrate their utilization.
Lindahl and Holter (1940) applied the extremely sensitive diver
method of Linderstr0m-Lang to the measurement of oxygen consumption of isolated animal and vegetal halves. They observed that both
halves use the same quantity of oxygen and that respiration increased
in the same proportion in the animal and vegetal halves during segmentation. Lastly, the sum of the quantities of oxygen used by the two
halves is equal to the quantity used by the entire egg. These observations
do not appear to favour the existence of a respiratory animal-vegetal
gradient. Nevertheless, we must notice that the isolation of animal and
vegetal halves, suppressing their mutual interactions, creates new
conditions, different from those existing in the entire egg, and that these
new conditions are liable to influence the consumption of oxygen.
Lindahl and Holter have completed these researches by studying the
effect of lithium, and of some other inhibitors of respiration, on isolated
animal and vegetal halves. Lithium inhibits the respiration of isolated
animal or vegetal halves in the same proportion. The same result is
obtained with cyanide and DL-glyceraldehyde. From all these results it
follows that the increase of respiration is not peculiar to the animal
halves, and that this function has the same sensitivity to the inhibitory
effects of lithium in animal and in vegetal halves.
Inhibitors of respiration have been studied in the whole egg and their
effects compared to those of lithium. Cyanide, carbon monoxide and
anaerobiosis partly inhibit oxidation and increase the vegetalizing
effects of lithium. If used alone, cyanide, carbon monoxide and anaerobiosis are not very effective. Carbon monoxide is the only one liable to
strengthen the vegetalization of isolated vegetal halves. Moreover, it is
also able to increase the animalization of isolated animal halves
(Runnström, 1928b; Hörstadius and Strömberg, 1940). The effect of
these agents can be attributed to an indirect action on metabolism, for
instance to the formation of an acid. In fact Lindhal (1940) has shown
that some organic acids, such as lactic, acetic and formic acids, strengthen
the vegetalizing action of lithium. This effect is also produced by bases
such as diethylamine (Lindahl, 1940), nicotine and guanidine (Lallier,
unpublished work). Thus it appears that the inhibitors of respiration do
not have vegetalizing effects comparable to those observed with lithium.
Let us now examine carbohydrate metabolism. In the sea urchin egg,
two pathways of carbohydrate breakdown have been identified (Fig. 10).