278
JOHN RUNNSTRÖM
in fact, serve as a test of the activity of these enzymes (Lundblad and
Runnström, 1962). Even if the activity of the sensitive enzymes Ε 1-E 3
had declined in the nonrefrigerated columns, the results indicate considerable changes in the distribution of the enzymes between the
fractions.
Figure 25A and Β give the ultraviolet absorption spectra of peaks I,
VIII, and X from Fig. 24. The differences between the material of unfertilized (A) and fertilized (B) eggs with respect to peak I is here more
clearly evident. There is no difference between the peaks VIII and a
slight one between peaks X.
Fraction I in Fig. 25A was somewhat opaque because of the presence
of colloidal particles. Most of the particles were removed by prolonged centrifugation at 10,000 g ; subsequently the extinction decreased somewhat; the difference between the values pertaining
to homogenates from unfertilized and from fertilized eggs was,
however, still considerable (G. Lundblad, private communication,
1963).
With a rather similar technique Monroy et al. (1961) investigated the
soluble proteins from unfertilized eggs and from eggs in different stages
after fertilization. They failed to discover the differences referred to
above. They centrifuged their homogenates at an acceleration of more
than 100,000 g, however, which probably removed Fraction I (Lundblad
and Lundblad, 1962). The changes occurring upon fertilization which
have been considered in this section are probably located not only in the
egg surface, but reflect rather a general change in the properties of certain proteins and nucleoproteins.
The data presented in Fig. 25A and Β tend to indicate that in homogenates from unfertilized eggs Fraction I contains ribonucleic acid,
whereas Fraction I in homogenates of fertilized eggs does not contain
or is poor in ribonucleic acid. The explanation may be that in unfertilized
eggs nucleic acids are strongly bound to proteins, and the complex can
pass through the DEAE-Sephadex. After fertilization the proteins may be
split from the nucleic acid, and, in virtue of its acid nature, the nucleic
acid does not pass through the column. There are other facts that point
to an unmasking of acid groups after fertilization, as, for example, the
increased staining with vital basic dyes and the firmer binding of these
to cell structure (Loeb, 1907).
The results of Lundblad (1952) are also in keeping with the abovementioned observations of Runnström on structural changes following
fertilization. His conclusion was that certain large aggregates of macromolecules are split up into more dispersed units (see also Runnström,
1955).
JOHN RUNNSTRÖM
in fact, serve as a test of the activity of these enzymes (Lundblad and
Runnström, 1962). Even if the activity of the sensitive enzymes Ε 1-E 3
had declined in the nonrefrigerated columns, the results indicate considerable changes in the distribution of the enzymes between the
fractions.
Figure 25A and Β give the ultraviolet absorption spectra of peaks I,
VIII, and X from Fig. 24. The differences between the material of unfertilized (A) and fertilized (B) eggs with respect to peak I is here more
clearly evident. There is no difference between the peaks VIII and a
slight one between peaks X.
Fraction I in Fig. 25A was somewhat opaque because of the presence
of colloidal particles. Most of the particles were removed by prolonged centrifugation at 10,000 g ; subsequently the extinction decreased somewhat; the difference between the values pertaining
to homogenates from unfertilized and from fertilized eggs was,
however, still considerable (G. Lundblad, private communication,
1963).
With a rather similar technique Monroy et al. (1961) investigated the
soluble proteins from unfertilized eggs and from eggs in different stages
after fertilization. They failed to discover the differences referred to
above. They centrifuged their homogenates at an acceleration of more
than 100,000 g, however, which probably removed Fraction I (Lundblad
and Lundblad, 1962). The changes occurring upon fertilization which
have been considered in this section are probably located not only in the
egg surface, but reflect rather a general change in the properties of certain proteins and nucleoproteins.
The data presented in Fig. 25A and Β tend to indicate that in homogenates from unfertilized eggs Fraction I contains ribonucleic acid,
whereas Fraction I in homogenates of fertilized eggs does not contain
or is poor in ribonucleic acid. The explanation may be that in unfertilized
eggs nucleic acids are strongly bound to proteins, and the complex can
pass through the DEAE-Sephadex. After fertilization the proteins may be
split from the nucleic acid, and, in virtue of its acid nature, the nucleic
acid does not pass through the column. There are other facts that point
to an unmasking of acid groups after fertilization, as, for example, the
increased staining with vital basic dyes and the firmer binding of these
to cell structure (Loeb, 1907).
The results of Lundblad (1952) are also in keeping with the abovementioned observations of Runnström on structural changes following
fertilization. His conclusion was that certain large aggregates of macromolecules are split up into more dispersed units (see also Runnström,
1955).