Comparative histological and histochemical studies of the larval tapeworms, Cyclustera ibisae and Glossocercus caribaenis. (Withdrawn).
Mummichogs (Fundulus heteroclitus) and striped killifish (Fundulus
majalis) were collected from the North Inlet-Winyah Bay near Georgetown,
South Carolina and examined for the presence of larval stages
(metascestodes) of two dilepidid tapeworms (Glossocercus caribaenis and
Cyclustera ibisae). These two species of tapeworms were found encysted in the liver and mesenteries of both fish hosts. The metacestodes were
isolated and fixed in buffered formalin and processed for histological
studies using standard (hematoxylin and eosin) staining procedures.
Formalin-fixed tissues were also stained with Periodic Acid Schiff(PAS)
and Gomori's Trichrome for histochemical caparisons of the two
species of metacestodes. The cyst wall of G. carbiaensis was slightly
thinner (~0.08 mm) than that of Cyclustera ibisae (~0.11 mm). In both
species, however, the cyst wall appeared to be made of two distinct
tissue layers. These metacestodes also differ in the thickness of
integument (~0.01 mm for G. caribaensis and ~0.04 mm for C. ibisae).
Other than the difference in general body form and size, these two
metacestodes appear to be very similar. Histochemical analysis suggests
presence of collagen in the tegument and out cyst wall, muscle fibers
below the tegument and around the scolex area, and keratin at the base
of the hooks in both species. Interestingly, very little or no glycogen
was detected in any of the tissues examined. Additional histochemical
tests could provide clues to distinguish between the two species of
metacestodes and possibly, to understand their metabolism.
Avery Tomlinson, Edna Steele
Department of Biology