80
IVAN (?00Dl%ODY
slowly absorbed from thcre to tJic cdls. Bayer (1955) has put forward a
model to siiggest the type of c.hcniicd pathways which may be involved
in vanadium acwimulation btit until a great deal more is known about
the actual pathways we cannot equiite his model with the processes
described by K d k und l
reported the presence of polysaccharides in
the ferrocytes of I’yurn stolonifere, and Endean (1960) and Kalk
( 1963a) both believed that vanadocytes synthesize polysaccharides
from si inple sugars in Phnllusio mam.millata and Ascidia pygmaea
Michaelsen respoctively. Smith ( L970b), 011 the other hand, believed
that polysciccharides we absent from the ferrocytes of Halocynthia
nurantiurn. The evidence froin stirdies on test formation already given
(p. 15) suggests that carbohydrate is fortncd directly from mantle
epithelium and not from moruls cells.
3. The iron wnrpound in Pyuridae
Although it is twenty yews siiicr 15ndean (1963) first discovered thet
iron and not vanadium was prcscnt in the blood cells of Pyura stolonifera, surprisingly little work has been done to follow up this interesting
disaovcry. The only confirmatory cvidence that this may be a characteristic of the stolidobrrinrh iis(*idiiins wmes from Smith (1 970a) who
worked with ?lnloc!~nfhin nurnntiuin in which iron is also present.
According to Endear1 tht. iroii cornpound is organically bound in the
ferrous state and is non-dialyhablc. It has markcd reducing properties
but is not such 11 powerful reducing ugciit as the vanadium compound
in Ascidiidae, ti fact also evident from Endeun’s (1955a) and Smith’R
(1970t~) results, in which it is shown that ferrocytes give only a greyish
colour with osmium tetroxide and not black as in the vanadocytes of
dscidia. In other respects the iron cornpound is also similar to haemovariadin. Clytolysis of the ferrocyte gives a brown acid golution eomparable to Heme’s red solution of vanadium and this oxidizes in air to
give a11 orange-brown precipitate. The ferrocyte also contains sulphuric
acid but probtibly not in such strong concentration as in vanadocytes
and Endean (1955a) considers that it is present to maintain the iron
compound in a reduced condition. The evidence therefore point8 to the
fact that in all essential respects the iron compound of the Pyuridae is
This ~notlel IS also folloacd by Riol~y el d. ( 1954) uritl by Koval’akll cind 1tctzw:vct
(1965) and seems to be incorrectly attributed us the work of these lattor authorR by
C8disle (1988).
IVAN (?00Dl%ODY
slowly absorbed from thcre to tJic cdls. Bayer (1955) has put forward a
model to siiggest the type of c.hcniicd pathways which may be involved
in vanadium acwimulation btit until a great deal more is known about
the actual pathways we cannot equiite his model with the processes
described by K d k und l
reported the presence of polysaccharides in
the ferrocytes of I’yurn stolonifere, and Endean (1960) and Kalk
( 1963a) both believed that vanadocytes synthesize polysaccharides
from si inple sugars in Phnllusio mam.millata and Ascidia pygmaea
Michaelsen respoctively. Smith ( L970b), 011 the other hand, believed
that polysciccharides we absent from the ferrocytes of Halocynthia
nurantiurn. The evidence froin stirdies on test formation already given
(p. 15) suggests that carbohydrate is fortncd directly from mantle
epithelium and not from moruls cells.
3. The iron wnrpound in Pyuridae
Although it is twenty yews siiicr 15ndean (1963) first discovered thet
iron and not vanadium was prcscnt in the blood cells of Pyura stolonifera, surprisingly little work has been done to follow up this interesting
disaovcry. The only confirmatory cvidence that this may be a characteristic of the stolidobrrinrh iis(*idiiins wmes from Smith (1 970a) who
worked with ?lnloc!~nfhin nurnntiuin in which iron is also present.
According to Endear1 tht. iroii cornpound is organically bound in the
ferrous state and is non-dialyhablc. It has markcd reducing properties
but is not such 11 powerful reducing ugciit as the vanadium compound
in Ascidiidae, ti fact also evident from Endeun’s (1955a) and Smith’R
(1970t~) results, in which it is shown that ferrocytes give only a greyish
colour with osmium tetroxide and not black as in the vanadocytes of
dscidia. In other respects the iron cornpound is also similar to haemovariadin. Clytolysis of the ferrocyte gives a brown acid golution eomparable to Heme’s red solution of vanadium and this oxidizes in air to
give a11 orange-brown precipitate. The ferrocyte also contains sulphuric
acid but probtibly not in such strong concentration as in vanadocytes
and Endean (1955a) considers that it is present to maintain the iron
compound in a reduced condition. The evidence therefore point8 to the
fact that in all essential respects the iron compound of the Pyuridae is
This ~notlel IS also folloacd by Riol~y el d. ( 1954) uritl by Koval’akll cind 1tctzw:vct
(1965) and seems to be incorrectly attributed us the work of these lattor authorR by
C8disle (1988).