24
VANCE TARTAR
pattern4 How do intact feeding organelles inhibit the formation of new
ones and is this inhibition transmitted posteriorly over all the stripes?
How does this state become converted to one of activation when the
feeding organelles are excised? In reorganizers and dividers, how does the
stripe pattern (if this is in fact what is principally involved) escape the
inhibitive presence of feeding organelles?
This scheme is derived from the observed fact that the clear stripes
bear complex fibrous structures. The pigmented or granular bands are
mostly ignored, for there is evidence that they are merely fill-ins
(Tartar, 1960a) although they may have an important role as spacers,
apart from the functions that the granules themselves may sustain. We
have not mentioned the kinetosomes, the basal bodies of the cilia which
lie in rows along the clear stripes and in the oral membranelles. It has
been attractive to regard these bodies as semi-autonomous 'plasma
genes' (Lwoff, 1950), and this appeals to atomistic habits of thinking.
The oral primordium, for instance, is usually described as an 'anarchic
field' or random aggregate of reduplicated kinetosomes which later
sprout cilia and autonomously achieve orderly arrangements and
fibrillar interconnections. Decorticated stentors have not been observed
to produce kinetosomes (cilia) de novo. But their replication has not
actually been observed and, as Roth (1956) appreciated, their appearance as mere tubular ends of cilia does not resemble what we would
expect in a self-replicating 'cilia factory'. Even Lwoff, whose beautiful
work with Chatton accomplished so much in the development of the
kinetosomal story, did not regard them as primary and referred to
cortical networks or other forces responsible for the orderly patterning
of kinetosomes.
The general import of the Stentor studies seems to lie in the revelation
that many of the principles and phenomena of morphogenesis characteristic of the Metazoa are also to be found or have their counterpart in this
unicellular form. Nor is Stentor unique, for transposition experiments of
Suzuki (1957) have revealed a similar morphogenesis in the ciliate
Blepharisma (see Tartar, 1960a). Briefly to recapitulate, dwarf and giant
forms are produced as with egg fragments or fused whole eggs; the
membranellar band seems to be the product of an inductive action
between wide- and fine-stripe areas, as the mouthparts are the result
of an inductive action of the posterior pole of the cell on the adjacent
end of the anläge; the oral primordium shows progressive determination
in time, developing place wise at first and then self-wise later; formed
structures exert an inhibitive action on the formation of their like;
minced stentors, like aggregations of isolated cells of lower animals, are
capable of reconstitution; relatively autonomous abnormalities of form
may develop; nuclei play an important biochemical role in morpho-
VANCE TARTAR
pattern4 How do intact feeding organelles inhibit the formation of new
ones and is this inhibition transmitted posteriorly over all the stripes?
How does this state become converted to one of activation when the
feeding organelles are excised? In reorganizers and dividers, how does the
stripe pattern (if this is in fact what is principally involved) escape the
inhibitive presence of feeding organelles?
This scheme is derived from the observed fact that the clear stripes
bear complex fibrous structures. The pigmented or granular bands are
mostly ignored, for there is evidence that they are merely fill-ins
(Tartar, 1960a) although they may have an important role as spacers,
apart from the functions that the granules themselves may sustain. We
have not mentioned the kinetosomes, the basal bodies of the cilia which
lie in rows along the clear stripes and in the oral membranelles. It has
been attractive to regard these bodies as semi-autonomous 'plasma
genes' (Lwoff, 1950), and this appeals to atomistic habits of thinking.
The oral primordium, for instance, is usually described as an 'anarchic
field' or random aggregate of reduplicated kinetosomes which later
sprout cilia and autonomously achieve orderly arrangements and
fibrillar interconnections. Decorticated stentors have not been observed
to produce kinetosomes (cilia) de novo. But their replication has not
actually been observed and, as Roth (1956) appreciated, their appearance as mere tubular ends of cilia does not resemble what we would
expect in a self-replicating 'cilia factory'. Even Lwoff, whose beautiful
work with Chatton accomplished so much in the development of the
kinetosomal story, did not regard them as primary and referred to
cortical networks or other forces responsible for the orderly patterning
of kinetosomes.
The general import of the Stentor studies seems to lie in the revelation
that many of the principles and phenomena of morphogenesis characteristic of the Metazoa are also to be found or have their counterpart in this
unicellular form. Nor is Stentor unique, for transposition experiments of
Suzuki (1957) have revealed a similar morphogenesis in the ciliate
Blepharisma (see Tartar, 1960a). Briefly to recapitulate, dwarf and giant
forms are produced as with egg fragments or fused whole eggs; the
membranellar band seems to be the product of an inductive action
between wide- and fine-stripe areas, as the mouthparts are the result
of an inductive action of the posterior pole of the cell on the adjacent
end of the anläge; the oral primordium shows progressive determination
in time, developing place wise at first and then self-wise later; formed
structures exert an inhibitive action on the formation of their like;
minced stentors, like aggregations of isolated cells of lower animals, are
capable of reconstitution; relatively autonomous abnormalities of form
may develop; nuclei play an important biochemical role in morpho-