Effect of chronic cold and submergence on blood oxygen transport in the turtle, chrysemys picta

Maginniss, Leigh A.; Tapper, Simon; Miller, Lyndsey M.

doi:10.1016/0034-5687(83)90013-0

Cited by 32 publications

(26 citation statements)

References 25 publications

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“…AH, a measure of the temperature sensitivity of hemoglobin-0, affinity was -10.5 kcal/mol 0,. This value is similar to those reported for the freshwater turtles Pseudemys scripta ( -10.5 kcal /mol; Burggren et al 1977 ) and Chrysemys picta ( -12.4 kcal/mol;Maginniss et al 1983). The large hemoglobin-0, temperature sensitivity exhibited by these turtes may be an adaptive mechanism to promote O2 unloading from blood to tissue during elevations in body temperature (Burggren et al 1977).…”

Section: Discussionsupporting

confidence: 88%

The in vitro respiratory and acid–base properties of blood and tissue from the Kemp's ridley sea turtle, Lepidochelys kempi

Stabenau¹,

Heming²

1994

Can. J. Zool.

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We determined the in vitro respiratory and acid–base properties of blood and tissue from Kemp's ridley sea turtles (Lepidochelys kempi). Blood O2 dissociation curves of ridley turtles were sigmoid, with a P50 of 31.2 ± 0.3 (mean ± SD) torr at 25 °C and pH 7.51. Increments in temperature or [Formula: see text] were associated with a shift of the O2 dissociation curves to the right and, hence, a reduction in haemoglobin–O2 binding affinity. The apparent heat of oxygenation, which is a measure of the temperature sensitivity of haemoglobin–O2 affinity, was −10.5 kcal/mol O2. The degree of cooperativity of O2 for hemoglobin binding sites, as measured by the Hill coefficient, increased at higher temperatures (20–30 °C at a [Formula: see text] of 37 torr), but was unaffected by changes in [Formula: see text] (37–52 torr at 25 °C). The CO2-Bohr effect was −0.34 torr/pH unit. The CO2 capacitance coefficient of whole blood and plasma declined as a function of increased [Formula: see text] (22 °C). Non-bicarbonate buffer capacities (22 °C) were 19.7, 18.5, and 6.4 slykes for whole blood, true plasma, and separated plasma, respectively. The skeletal muscle myoglobin content was 3.1 ± 0.84 mg∙g−1 of tissue. The respiratory and acid–base properties of blood and tissue from Kemp's ridley sea turtles are consistent with those of species that utilize lung O2 stores during long-term aerobic dives. The enhanced haemoglobin–O2 temperature sensitivity exhibited by the ridley turtle could be a physiological adaptation for life in coastal environments that typically undergo substantial fluctuations in temperature.

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Section: Discussionsupporting

confidence: 88%

The in vitro respiratory and acid–base properties of blood and tissue from the Kemp's ridley sea turtle, Lepidochelys kempi

Stabenau¹,

Heming²

1994

Can. J. Zool.

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“…Hematocrit comparisons in reptiles are however, complicated by differences in the temperatures at which the reptiles are normally active, such that hematocrit may be limited by the expected rise in blood viscosity as temperature falls (Pough, 1980). Values of MCHC were also high, consistent with the concept that high values of MCHC are typical of diving reptiles, compared with non-divers (Wood and Johansen, 1974;Seymour et al, 1981;Maginniss et al, 1983;Birchard et al, 1984), as is also the case within the Mammalia (Kooyman et al, 1981). In sea turtles also, pulmonary oxygen stores are supplemented by high blood oxygen carrying capacity and appear adequate to sustain predominantly aerobic dives (Lutz and Bentley, 1985).…”

Section: Discussionsupporting

confidence: 48%

Blood viscosity and hematocrit in the estuarine crocodile, Crocodylus porosus

Wells

Beard

Grigg

1991

Comparative Biochemistry and Physiology Part A: Physiology

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Abstract1. Viscosities of whole blood and plasma from Crocodylus porosus were low in comparison with other diving animals when measured over a range of shear rates at 30°C (e.g. 2.89 ± 0.07 mPa.sec and 1.67 ± 0.06 mPa.sec respectively, at a shear rate of 450 sec-1). 2. Hematocrit (19.2 ± 0.5%) and mean cell hemoglobin concentration (262 ± 23 g/l) are high in crocodiles compared with non-diving reptiles. 3. Nucleation of the red blood cell does not seem to have affected viscosity. 4. The potential for oxygen transport was estimated from pooled blood reconstituted to a range of hematocrits and used to predict an optimal hematocrit of 38%, which greatly exceeded measured values. 5. Low blood viscosity is associated with low flow resistance and may assist circulation during the low blood pressure events occurring during diving.

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“…Before turtles become anoxic during winter submergence, there is a gradual transition from aerobic to anaerobic metabolism (24), as ambient temperature and metabolic rate decrease, which may, in principle, require adjustments of blood O 2 transport, while animals undergo prolonged diving but still have access to air. In the case of the painted turtle (Chrysemys picta), depression of metabolism results in a gradual decrease in the erythrocytic ATP concentration (28). Given that ATP is the major organic phosphate in turtle red blood cells (3,28) and that it serves as the major allosteric regulator of O 2 affinity in the hemoglobins (Hbs) of turtles and most other ectothermic vertebrates (48), reductions in ATP levels might be expected to gradually induce a left shift of the O 2 -binding curve and decrease O 2 delivery to tissues during the progressive decrease in the O 2 consumption rate (28).…”

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confidence: 99%

“…In the case of the painted turtle (Chrysemys picta), depression of metabolism results in a gradual decrease in the erythrocytic ATP concentration (28). Given that ATP is the major organic phosphate in turtle red blood cells (3,28) and that it serves as the major allosteric regulator of O 2 affinity in the hemoglobins (Hbs) of turtles and most other ectothermic vertebrates (48), reductions in ATP levels might be expected to gradually induce a left shift of the O 2 -binding curve and decrease O 2 delivery to tissues during the progressive decrease in the O 2 consumption rate (28). At the same time, the decrease in temperature during winter will have a similar effect on the Hb-O 2 affinity (10,28).…”

mentioning

confidence: 99%

“…Given that ATP is the major organic phosphate in turtle red blood cells (3,28) and that it serves as the major allosteric regulator of O 2 affinity in the hemoglobins (Hbs) of turtles and most other ectothermic vertebrates (48), reductions in ATP levels might be expected to gradually induce a left shift of the O 2 -binding curve and decrease O 2 delivery to tissues during the progressive decrease in the O 2 consumption rate (28). At the same time, the decrease in temperature during winter will have a similar effect on the Hb-O 2 affinity (10,28). In principle, erythrocytic responses to hypoxic or anoxic conditions could also involve regulatory adjustments in the relative concentrations of alternative Hb isoforms (isoHbs) that have different O 2 -binding properties.…”

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confidence: 99%

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Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

Damsgaard

Storz

Hoffmann

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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When freshwater turtles acclimatize to winter hibernation, there is a gradual transition from aerobic to anaerobic metabolism, which may require adjustments of blood O2 transport before turtles become anoxic. Here, we report the effects of protons, anionic cofactors, and temperature on the O2-binding properties of isolated hemoglobin (Hb) isoforms, HbA and HbD, in the turtle Trachemys scripta. We determined the primary structures of the constituent subunits of the two Hb isoforms, and we related the measured functional properties to differences in O2 affinity between untreated hemolysates from turtles that were acclimated to normoxia and anoxia. Our data show that HbD has a consistently higher O2 affinity compared with HbA, whereas Bohr and temperature effects, as well as thiol reactivity, are similar. Although sequence data show amino acid substitutions at two known β-chain ATP-binding site positions, we find high ATP affinities for both Hb isoforms, suggesting an alternative and stronger binding site for ATP. The high ATP affinities indicate that, although ATP levels decrease in red blood cells of turtles acclimating to anoxia, the O2 affinity would remain largely unchanged, as confirmed by O2-binding measurements of untreated hemolysates from normoxic and anoxic turtles. Thus, the increase in blood-O2 affinity that accompanies winter acclimation is mainly attributable to a decrease in temperature rather than in concentrations of organic phosphates. This is the first extensive study on freshwater turtle Hb isoforms, providing molecular evidence for adaptive changes in O2 transport associated with acclimation to severe hypoxia.

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Effect of chronic cold and submergence on blood oxygen transport in the turtle, chrysemys picta

Cited by 32 publications

References 25 publications

The in vitro respiratory and acid–base properties of blood and tissue from the Kemp's ridley sea turtle, Lepidochelys kempi

The in vitro respiratory and acid–base properties of blood and tissue from the Kemp's ridley sea turtle, Lepidochelys kempi

Blood viscosity and hematocrit in the estuarine crocodile, Crocodylus porosus

Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

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