110
A L B E R T O M O N R O Y A N D R A C H E L E M A G G I O
FIG. 9. (a) The cells of the primary mesenchyme in a normal mesenchyme blastula of
Paracentrotus lividus.
on the other hand, during the following period of rapid increase in the
rate of oxygen consumption, the rate of incorporation of labelled aminoacids into proteins undergoes a slight decrease on the whole. (2) That the
proteins synthesized at an early stage, or a fraction thereof, are of
importance for the differentiation of the primary mesenchyme and
perhaps of the whole vegetative territory of the embryo. It may be
appropriate to remember here that the early cleavage (but particularly
the one coinciding with the rapid increase of oxygen consumption) is
the phase of the highest Li-sensitivity (Lindahl, 1936, 1940). (3) That
during the first wave of protein synthesis there is no evidence of synthesis
oînew proteins (i.e., proteins not already present in the unfertilized egg,
but it seems likely that the egg only resumes the synthetic processes
that were going on during oogenesis and which had been arrested at a
certain stage during the course of maturation (see also Runnström,
1961). This may explain w h y no new antigens—i.e., those different from
A L B E R T O M O N R O Y A N D R A C H E L E M A G G I O
FIG. 9. (a) The cells of the primary mesenchyme in a normal mesenchyme blastula of
Paracentrotus lividus.
on the other hand, during the following period of rapid increase in the
rate of oxygen consumption, the rate of incorporation of labelled aminoacids into proteins undergoes a slight decrease on the whole. (2) That the
proteins synthesized at an early stage, or a fraction thereof, are of
importance for the differentiation of the primary mesenchyme and
perhaps of the whole vegetative territory of the embryo. It may be
appropriate to remember here that the early cleavage (but particularly
the one coinciding with the rapid increase of oxygen consumption) is
the phase of the highest Li-sensitivity (Lindahl, 1936, 1940). (3) That
during the first wave of protein synthesis there is no evidence of synthesis
oînew proteins (i.e., proteins not already present in the unfertilized egg,
but it seems likely that the egg only resumes the synthetic processes
that were going on during oogenesis and which had been arrested at a
certain stage during the course of maturation (see also Runnström,
1961). This may explain w h y no new antigens—i.e., those different from