Functional properties of hemoglobin and whole blood in an aquatic mammal, the Amazonian manatee (Trichechus inunguis)

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 = 10.2, 9.9, and 10.9 mmHg, respectively) by a similar degree to that of Asian elephant Hb 27 . This finding extends previous studies conducted on sirenian Hbs 4,28,29 , and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 –affinity was observed in the presence of Cl − and DPG (P 50 = 14.3 mmHg).…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 = 10.2, 9.9, and 10.9 mmHg, respectively) by a similar degree to that of Asian elephant Hb 27 . This finding extends previous studies conducted on sirenian Hbs 4,28,29 , and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 –affinity was observed in the presence of Cl − and DPG (P 50 = 14.3 mmHg).…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 =10.2, 9.9, and 10.9 mm Hg, respectively) by a similar degree to that of Asian elephant Hb ( Campbell et al, 2010a ). This finding extends previous studies conducted on sirenian Hbs ( Farmer et al, 1979 ; McCabe et al, 1978 ; Signore et al, 2019 ), and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 -affinity was observed in the presence of Cl − and DPG (P 50 =14.3 mm Hg).…”

“…These β82 replacements thereby presumably decrease the rate of Hb turnover and increase the half-life of the protein ( Strader et al, 2017 ), which may contribute to the mild polycythemia in humans carrying this substitution ( Bardakjian et al, 1985 ; Moo-Penn et al, 1976 ). Blood with an elevated O 2 carrying capacity is typical of most mammalian divers, where it increases onboard O 2 stores and extends dive times ( Ponganis, 2011 ), but is not observed in extant sirenians ( Farmer et al, 1979 ; White et al, 1976 ; Wong et al, 2018 ). However, any solubility-driven increases in red blood cell Hb concentration resulting from the β82Lys→Asn exchange would have allowed Steller’s sea cows to maintain an elevated rate of tissue O 2 delivery to meet their metabolic demands during extended underwater foraging intervals.…”

“…For example, blood from a 5 month-old elephant fetus was shown to contain two distinct Hb components, although only a single (adult) Hb component is present in 12-month-old fetal and adult blood ( Riegel et al, 1967 ). Likewise, the blood of manatee calves contains a second isoHb (comprising ~5% of total Hb; Farmer et al, 1979 ), which moreover appears to exhibit O 2 binding properties distinct from that of maternal blood ( White et al, 1976 ). It is thus conceivable that the second Hb component in newborn manatee blood (and potentially other sirenians) arises from the delayed expression of HBG (which expresses the γ-chain of HbF).…”

Emergence of a Chimeric Globin Pseudogene and Increased Hemoglobin Oxygen Affinity Underlie the Evolution of Aquatic Specializations in Sirenia

“…To confirm and extend previous work suggesting that sirenians possess a high O 2 -affinity Hb phenotype (McCabe et al. 1978; Farmer et al. 1979), we produced recombinant adult-type sirenian Hbs, measured their O 2 binding properties at physiologically relevant effector concentrations and temperature (see methods), and compared them with those of native rock hyrax Hb and previously published values for the Asian elephant and woolly mammoth measured under identical test conditions (Campbell, Roberts, et al.…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 = 10.2, 9.9, and 10.9 mmHg, respectively) by a similar degree to that of Asian elephant Hb 27 . This finding extends previous studies conducted on sirenian Hbs 4,28,29 , and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 –affinity was observed in the presence of Cl − and DPG (P 50 = 14.3 mmHg).…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 =10.2, 9.9, and 10.9 mm Hg, respectively) by a similar degree to that of Asian elephant Hb ( Campbell et al, 2010a ). This finding extends previous studies conducted on sirenian Hbs ( Farmer et al, 1979 ; McCabe et al, 1978 ; Signore et al, 2019 ), and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 -affinity was observed in the presence of Cl − and DPG (P 50 =14.3 mm Hg).…”

“…These β82 replacements thereby presumably decrease the rate of Hb turnover and increase the half-life of the protein ( Strader et al, 2017 ), which may contribute to the mild polycythemia in humans carrying this substitution ( Bardakjian et al, 1985 ; Moo-Penn et al, 1976 ). Blood with an elevated O 2 carrying capacity is typical of most mammalian divers, where it increases onboard O 2 stores and extends dive times ( Ponganis, 2011 ), but is not observed in extant sirenians ( Farmer et al, 1979 ; White et al, 1976 ; Wong et al, 2018 ). However, any solubility-driven increases in red blood cell Hb concentration resulting from the β82Lys→Asn exchange would have allowed Steller’s sea cows to maintain an elevated rate of tissue O 2 delivery to meet their metabolic demands during extended underwater foraging intervals.…”

“…For example, blood from a 5 month-old elephant fetus was shown to contain two distinct Hb components, although only a single (adult) Hb component is present in 12-month-old fetal and adult blood ( Riegel et al, 1967 ). Likewise, the blood of manatee calves contains a second isoHb (comprising ~5% of total Hb; Farmer et al, 1979 ), which moreover appears to exhibit O 2 binding properties distinct from that of maternal blood ( White et al, 1976 ). It is thus conceivable that the second Hb component in newborn manatee blood (and potentially other sirenians) arises from the delayed expression of HBG (which expresses the γ-chain of HbF).…”

Emergence of a Chimeric Globin Pseudogene and Increased Hemoglobin Oxygen Affinity Underlie the Evolution of Aquatic Specializations in Sirenia

“…To confirm and extend previous work suggesting that sirenians possess a high O 2 -affinity Hb phenotype (McCabe et al. 1978; Farmer et al. 1979), we produced recombinant adult-type sirenian Hbs, measured their O 2 binding properties at physiologically relevant effector concentrations and temperature (see methods), and compared them with those of native rock hyrax Hb and previously published values for the Asian elephant and woolly mammoth measured under identical test conditions (Campbell, Roberts, et al.…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 = 10.2, 9.9, and 10.9 mmHg, respectively) by a similar degree to that of Asian elephant Hb 27 . This finding extends previous studies conducted on sirenian Hbs 4,28,29 , and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 –affinity was observed in the presence of Cl − and DPG (P 50 = 14.3 mmHg).…”

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller’s sea cows

“…Of note, the O 2 affinity of dugong, ancestral dugongid, and manatee Hbs was reduced in the presence of Cl − and DPG (P 50 =10.2, 9.9, and 10.9 mm Hg, respectively) by a similar degree to that of Asian elephant Hb ( Campbell et al, 2010a ). This finding extends previous studies conducted on sirenian Hbs ( Farmer et al, 1979 ; McCabe et al, 1978 ; Signore et al, 2019 ), and reveals that the high O 2 affinity of dugong and manatee blood is not attributable to decreased allosteric effector sensitivity. Conversely, Steller’s sea cow Hb was shown to be markedly less responsive to allosteric effectors, as only a moderate reduction in O 2 -affinity was observed in the presence of Cl − and DPG (P 50 =14.3 mm Hg).…”

“…These β82 replacements thereby presumably decrease the rate of Hb turnover and increase the half-life of the protein ( Strader et al, 2017 ), which may contribute to the mild polycythemia in humans carrying this substitution ( Bardakjian et al, 1985 ; Moo-Penn et al, 1976 ). Blood with an elevated O 2 carrying capacity is typical of most mammalian divers, where it increases onboard O 2 stores and extends dive times ( Ponganis, 2011 ), but is not observed in extant sirenians ( Farmer et al, 1979 ; White et al, 1976 ; Wong et al, 2018 ). However, any solubility-driven increases in red blood cell Hb concentration resulting from the β82Lys→Asn exchange would have allowed Steller’s sea cows to maintain an elevated rate of tissue O 2 delivery to meet their metabolic demands during extended underwater foraging intervals.…”

“…For example, blood from a 5 month-old elephant fetus was shown to contain two distinct Hb components, although only a single (adult) Hb component is present in 12-month-old fetal and adult blood ( Riegel et al, 1967 ). Likewise, the blood of manatee calves contains a second isoHb (comprising ~5% of total Hb; Farmer et al, 1979 ), which moreover appears to exhibit O 2 binding properties distinct from that of maternal blood ( White et al, 1976 ). It is thus conceivable that the second Hb component in newborn manatee blood (and potentially other sirenians) arises from the delayed expression of HBG (which expresses the γ-chain of HbF).…”

Emergence of a Chimeric Globin Pseudogene and Increased Hemoglobin Oxygen Affinity Underlie the Evolution of Aquatic Specializations in Sirenia

“…To confirm and extend previous work suggesting that sirenians possess a high O 2 -affinity Hb phenotype (McCabe et al. 1978; Farmer et al. 1979), we produced recombinant adult-type sirenian Hbs, measured their O 2 binding properties at physiologically relevant effector concentrations and temperature (see methods), and compared them with those of native rock hyrax Hb and previously published values for the Asian elephant and woolly mammoth measured under identical test conditions (Campbell, Roberts, et al.…”