Short Communication Different Hemocyanin Oxygen-affinities in Carcinus Maenas from Maine and Arcachon
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چکیده
The green or shore crab Carcinus maenas (Linnaeus) is believed to have emigrated by ship from its native Europe to the Atlantic coast of North America. The chronological sequence of new records suggests the arrival in New York of pioneer individuals in the early 19th century, followed by gradual northward extension of the species range (Almaca, 1963; J. T. Carlton, personal communication). The number of immigrations and the present genetic relationships of various populations are unknown. In an investigation of the CO2 sensitivity of the hemocyanins (Hcs), we noticed (though did not report) that bur O2 affinity data for North American crabs collected in Maine (Mangum and Burnett, 1986) differed from those in the literature for European crabs collected in France (Truchot, 1973). While the magnitude of the CO2 effect on oxygen affinity was essentially identical, the absolute values for the two populations (both control and experimental) were quite different. Differences in O2 binding are expected when prior treatment, ionic composition of the solvent and temperature, for example, are not held constant. Our experience has been, however, that data for the same O2 carriers, carefully collected under identical conditions, are indistinguishable, even when fundamentally different methods are employed (e.g. Mangum and Lykkeboe, 1979; Mangum and Burnett, 1986). Consequently, we have investigated the O2 binding properties of the Hcs from North American and European representatives of C. maenas more thoroughly in order to examine the possibility of intrinsic differences. To control for possible effects of thermal and/or seasonal acclimation, known in this and related species (Truchot, 1975; Mauro and Mangum, 1982), and of differences between the sexes (not detected by Mangum, 1990), we obtained females from Boothbay Harbor, Maine, in early March for comparison with our earlier data for males collected from Salsbury Cove, Maine, in July (Mangum and
منابع مشابه
Thermodynamics of oxygenation-linked proton and lactate binding govern the temperature sensitivity of O2 binding in crustacean (Carcinus maenas) hemocyanin.
With the aim of understanding the molecular underpinnings of the enormous variation in the temperature sensitivity of hemocyanin-O2 affinity encountered in crustaceans, we measured O2 binding to Carcinus maenas hemocyanin at two temperatures, varying pH values and in the absence and presence of lactate ions in order to assess the contributions of oxygenation-linked binding of protons (the Bohr ...
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