. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 452 D. W. ENGEL AND M. BROUWER HEHOCYRNIN Zn/Cu-MT Zn. HMINO RCIDS ENERGY METHBOLISM LYSOSOMES I (EXCRETION) ( ce I I u I or si ough i ng ) FECES URINE Figure 7. A flow diagram of the synthetic and catabolic pathways tor hemocyanin and the interactions between copper, zinc, and copper/ zmc-MT in the digestive gland of the blue crab immediately after ecdysis and during the later postmolt recovery period. The diagram includes the pathways for detoxification of copper released from hemocyanin, excre- tion of copper and zinc (En
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 452 D. W. ENGEL AND M. BROUWER HEHOCYRNIN Zn/Cu-MT Zn. HMINO RCIDS ENERGY METHBOLISM LYSOSOMES I (EXCRETION) ( ce I I u I or si ough i ng ) FECES URINE Figure 7. A flow diagram of the synthetic and catabolic pathways tor hemocyanin and the interactions between copper, zinc, and copper/ zmc-MT in the digestive gland of the blue crab immediately after ecdysis and during the later postmolt recovery period. The diagram includes the pathways for detoxification of copper released from hemocyanin, excre- tion of copper and zinc (Engel, 1987; Engel and Brouwer, 1987; and Al- Mohanna and Nott. 1989), and the presence of a lower molecular weight compound that is active in the transfer of copper to the apoprotein during hemocyanin synthesis (Brouwer, unpub. data). tentatively classified as a Class II-MT, has been found effective in restoring the oxygen binding capacity of apo- hemocyanin (Brouwer et al. 1989). Whether copper ex- change occurs between the Class I and II-MTs remains to be demonstrated. This investigation gives further support to the hypoth- esis that the function of metallothionein in normal or- ganisms is in the regulation of nutritional metals. Through the use of the normal crustacean growth process of molt- ing, we have been able to identify some of the functional mechanisms of cytosolic metal regulation involving MT. These data also serve to point out that if a protein such as MT is to be used as an indicator of animal health, the processes that control its abundance and turnover must be demonstrated. Acknowledgments The authors thank Mr. William J. Bowen, III for his efforts to collect the tissue samples from molting blue crabs at the desired times, and the local crab shedders for their cooperation (, Mr. Garry Culpepper, Hooper Family Seafood, and Pitmann Seafood). The authors also ac- knowledge the assistance of the ADP/Biometrics Unit in the statistical analysis of the data and in
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
