76
MARINE MOLLUSCS AS HOSTS FOR SYMBIOSES
five of the plasma1 fractions (Fig. 15). Confirmation of the proteinaceous
nature of the agglutinin was in the establishment of a linear correlation
between the agglutination titers of the plasma samples and their total
protein concentrations. I n the same paper we postulated that this
natural humoral factor may be responsible for the apparent parasitefree condition of Viviparus malleatus, with the factor acting as a natural
defense mechanism.
(point of application)
A. Normal, unadsorbed serum
(point of application)
c5 I
8. Adsorbed serum
(point of application)
C. Diluted serum
FIG. 15. Electrophoretic patterns of plasma (sera) of Viwiparus malleafus. The systern
ernployed was paper electrophoresis (Beckman Durrum type) with Verona1 buffer
a t pH 8.6. (After Cheng and Sanders, 1962.)
At this point it should be mentioned that naturally occurring
humoral factors can prevent establishment of a parasite by means other
than killing the penetrating parasite if such occurs. The findings of
Cheng et al. (196613) relative to the effects of marine pelecypod plasma,
especially the plasma of Crassostrea gigas cited earlier, may be interpreted to reflect the occurrence of an innate humoral factor which
prevented parasitization by Himasthla quissetensis metacercariae by
preventing the cercariae from penetrating through immobilization.
Acquired resistance. I n molluscs the importance of phagocytosis
and encapsulation as forms of internal defense mechanisms is well
established but acquired antibodies have not yet been demonstrated.
MARINE MOLLUSCS AS HOSTS FOR SYMBIOSES
five of the plasma1 fractions (Fig. 15). Confirmation of the proteinaceous
nature of the agglutinin was in the establishment of a linear correlation
between the agglutination titers of the plasma samples and their total
protein concentrations. I n the same paper we postulated that this
natural humoral factor may be responsible for the apparent parasitefree condition of Viviparus malleatus, with the factor acting as a natural
defense mechanism.
(point of application)
A. Normal, unadsorbed serum
(point of application)
c5 I
8. Adsorbed serum
(point of application)
C. Diluted serum
FIG. 15. Electrophoretic patterns of plasma (sera) of Viwiparus malleafus. The systern
ernployed was paper electrophoresis (Beckman Durrum type) with Verona1 buffer
a t pH 8.6. (After Cheng and Sanders, 1962.)
At this point it should be mentioned that naturally occurring
humoral factors can prevent establishment of a parasite by means other
than killing the penetrating parasite if such occurs. The findings of
Cheng et al. (196613) relative to the effects of marine pelecypod plasma,
especially the plasma of Crassostrea gigas cited earlier, may be interpreted to reflect the occurrence of an innate humoral factor which
prevented parasitization by Himasthla quissetensis metacercariae by
preventing the cercariae from penetrating through immobilization.
Acquired resistance. I n molluscs the importance of phagocytosis
and encapsulation as forms of internal defense mechanisms is well
established but acquired antibodies have not yet been demonstrated.