. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 5. Continued. not be completely degraded or not broken down at all, but rather retained and functionally altered. The metacercariae possess a monomelic hemoglobin with an approximate molecular weight of 16,000 and two different globin forms. This corresponds to the re- sults found for the trematodes Fasciola gigantica (Lutz and Siddiqi, 1967), Philophthalmus megalurus, and Echinostoma revolution (Cain, 1969a), each of which possess two globin forms of hemoglobin with molecular weights ranging from 15 to 17,000 daltons
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 5. Continued. not be completely degraded or not broken down at all, but rather retained and functionally altered. The metacercariae possess a monomelic hemoglobin with an approximate molecular weight of 16,000 and two different globin forms. This corresponds to the re- sults found for the trematodes Fasciola gigantica (Lutz and Siddiqi, 1967), Philophthalmus megalurus, and Echinostoma revolution (Cain, 1969a), each of which possess two globin forms of hemoglobin with molecular weights ranging from 15 to 17,000 daltons. The two glo- bins found in metacercaria tissues are distinct from the globins of .4. ornata coelomic cell hemoglobins based on spectral differences and on elution differences using ion exchange media. Tritiated glycine was found in gel filtration fractions that contain metacercaria hemoglobins. This evidence, along with ion exchange elution differences, spectral and functional differences, strongly suggests that at least the globin portion of the metacercaria hemoglobin is pro- duced in the animal. Because glycine is also used in the synthesis of the protoporphyrin ring(Guyton, 1986), the appearance of label in metacercaria hemoglobin may also indicate the de novo synthesis of heme. Alterna- tively, heme groups could be obtained directly from in- gested host hemoglobins, making synthesis unnecessary. Cain (1969b) showed that Fasciolopsis buski did not pro- duce heme, but did synthesize the globin portion of its hemoglobin. This species also ingests its host's hemoglo- bin and, therefore, has an exogenous supply of heme. On the basis of the available evidence, the origin of heme in the metacercaria hemoglobin is unresolved. The metacercariae also have a large molecular weight heme protein fraction. This fraction elutes as two distinct peaks upon ion exchange chromatography that corre- spond to two consistent hemoglobin peaks present in the whole metacercaria lysate. These two
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
