318
JOHN RUNNSTRÖM
of such analogies should also stimulate an intensified study of the problem of egg activation.
The cortical particle is a vehicle for the transportation of at least
four different components. In one of these, the lamella, a basal-apical
gradient could be distinguished. In certain respects the particles resemble
the vacuoles in cartilage cells that mediate the secretion of sulfated mucopolysaccharides. In both cases the membranes of the particles contribute
to the extension or renewal of the plasma membrane of the cell (see
Godman and Porter, 1960).
A basic question is the following: How is the information provided
that directs the differentiation of the ordered structures of the cortical
particles?
It was recognized that related species or genera must have genes in
common which carry information for characteristic traits in the structure
of the cortical particles. It is striking how well the similarities and
differences in the structure of cortical particles seem to reflect the affinities between species or genera that have been inferred from other morphological criteria.
How is the information from different genes coordinated in the differentiation of the cortical particles? There may be a genetic coordination
about which nothing is known in the present cases. There may, however,
also be a coordination at the level of the nongene-carrying part of the
nucleus in which the nuclear membrane plays a role; systems of endoplasmic vesicles are released carrying ribosomes along with them and
occupying certain territories of cytoplasm, where series of cortical
particles arise with direct contribution from ribosomes. The endoplasmic
vesicles, on the other hand, seem to contribute by creating both the
membranes and parts of the interior of the particles. The final order
cannot, however, be attained only by accumulation of proteins with
different amino acid sequences and subsequent enzymatic capabilities.
An interaction between the different proteins must occur which may lead
to a complete separation of certain macromolecules (incompatibility) or
to arrangement in gradients of other macromolecules (graded compatibilities or incompatibilities). In this way an ordering may result as
the consequence of a process that does not require direct supply of energy. A most versatile model for such processes is found in Albertsson's
(1960) studies on phase separation and the partition of macromolecules
and cell components between phases. On the molecular level the same
sorting process may occur as between cells (see Gustaf son and Wolpert,
1963; Steinberg, 1964).
In the activation of the egg all kinds of cell phenomena meet together.
Let us only refer here to some of them. Different components may be at-
JOHN RUNNSTRÖM
of such analogies should also stimulate an intensified study of the problem of egg activation.
The cortical particle is a vehicle for the transportation of at least
four different components. In one of these, the lamella, a basal-apical
gradient could be distinguished. In certain respects the particles resemble
the vacuoles in cartilage cells that mediate the secretion of sulfated mucopolysaccharides. In both cases the membranes of the particles contribute
to the extension or renewal of the plasma membrane of the cell (see
Godman and Porter, 1960).
A basic question is the following: How is the information provided
that directs the differentiation of the ordered structures of the cortical
particles?
It was recognized that related species or genera must have genes in
common which carry information for characteristic traits in the structure
of the cortical particles. It is striking how well the similarities and
differences in the structure of cortical particles seem to reflect the affinities between species or genera that have been inferred from other morphological criteria.
How is the information from different genes coordinated in the differentiation of the cortical particles? There may be a genetic coordination
about which nothing is known in the present cases. There may, however,
also be a coordination at the level of the nongene-carrying part of the
nucleus in which the nuclear membrane plays a role; systems of endoplasmic vesicles are released carrying ribosomes along with them and
occupying certain territories of cytoplasm, where series of cortical
particles arise with direct contribution from ribosomes. The endoplasmic
vesicles, on the other hand, seem to contribute by creating both the
membranes and parts of the interior of the particles. The final order
cannot, however, be attained only by accumulation of proteins with
different amino acid sequences and subsequent enzymatic capabilities.
An interaction between the different proteins must occur which may lead
to a complete separation of certain macromolecules (incompatibility) or
to arrangement in gradients of other macromolecules (graded compatibilities or incompatibilities). In this way an ordering may result as
the consequence of a process that does not require direct supply of energy. A most versatile model for such processes is found in Albertsson's
(1960) studies on phase separation and the partition of macromolecules
and cell components between phases. On the molecular level the same
sorting process may occur as between cells (see Gustaf son and Wolpert,
1963; Steinberg, 1964).
In the activation of the egg all kinds of cell phenomena meet together.
Let us only refer here to some of them. Different components may be at-