Isohemoglobin Differentiation in the Bimodal-breathing Amazon Catfish Hoplosternum littorale

Weber, Roy E.; Fago, Angela; Val, Adalberto Luı́s; Bang, Anny; Hauwaert, Marie-Louise Van; Dewilde, Sylvia; Zal, Franck; Moëns, Luc

doi:10.1074/jbc.m001209200

Cited by 46 publications

(42 citation statements)

References 56 publications

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“…IsoHb Composition of Avian Red Cells-In contrast to the variable patterns of Hb heterogeneity in fishes and other ectothermic vertebrate groups (5,(7)(8)(9)(71)(72)(73), the two-component HbA/HbD system of birds is remarkably consistent. A number of bird species are known to express three or four structurally distinct isoHbs in definitive erythrocytes (11,14,15,74,75), but in all such cases HbA and HbD (i.e.…”

Section: Discussionmentioning

confidence: 99%

“…We measured O 2 equilibrium curves for purified HbA and HbD isoforms using a modified gas diffusion chamber coupled to cascaded Wösthoff pumps for mixing pure N 2 (99.998%), O 2 , and atmospheric air (9). Changes in the absorbance spectra of thin layer Hb solutions (4 l) were measured in conjunction with stepwise changes in the partial pressure of O 2 (PO 2 ) inside the chamber.…”

Section: Methodsmentioning

confidence: 99%

“…Despite this detailed understanding, a number of vexing questions about Hb function continue to challenge comparative biochemists and physiologists. One such question concerns the functional and adaptive significance of co-expressing multiple, structurally distinct Hb isoforms (isoHbs) 2 (2,(5)(6)(7)(8)(9). Most vertebrate species express functionally distinct isoHbs during different stages of pre-natal development, and in many groups it is also common to co-express different isoHbs during postnatal life.…”

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Gene Duplication and the Evolution of Hemoglobin Isoform Differentiation in Birds

Grispo

Natarajan

Projecto-Garcia

et al. 2012

Journal of Biological Chemistry

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Background:The functional significance of hemoglobin heterogeneity remains a mystery. Results: In adult birds, the HbD isoform (related to embryonic hemoglobin) exhibits distinct oxygenation properties relative to the major HbA isoform. Conclusion: Substitutions that distinguish HbD from HbA are not shared with embryonic hemoglobin. Significance: Differences between isoforms stem from derived (nonancestral) changes in duplicated genes, not from the retention of an ancestral condition.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Gene Duplication and the Evolution of Hemoglobin Isoform Differentiation in Birds

Grispo

Natarajan

Projecto-Garcia

et al. 2012

Journal of Biological Chemistry

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“…Separation of the ␣-and ␤-chains, enzymatic digestions, and isolation and amino acid sequence analyses of the peptides were carried out as previously described (61). (P 50 ϭ 7.3 mmHg at 20°C, pH 7.5) (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Hb purification was carried out at 0-5°C as previously described (61). Hb heterogeneity was investigated by isoelectric focusing in 110-ml LKB columns (Bromma, Sweden) in 0.87% ampholines (pH 6.7-7.7) (46).…”

Section: Methodsmentioning

confidence: 99%

Novel mechanism for high-altitude adaptation in hemoglobin of the Andean frogTelmatobius peruvianus

Weber

Ostojic²,

Fago

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

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In contrast to birds and mammals, no information appears to be available on the molecular adaptations for O2 transport in high-altitude ectothermic vertebrates. We investigated Hb of the aquatic Andean frog Telmatobius peruvianus from 3,800-m altitude as regards isoform differentiation, sensitivity to allosteric cofactors, and primary structures of the ␣-and ␤-chains, and we carried out comparative O2-binding measurements on Hb of lowland Xenopus laevis. The three T. peruvianus isoHbs show similar functional properties. The high O2 affinity of the major component results from an almost complete obliteration of chloride sensitivity, which correlates with two ␣-chain modifications: blockage of the NH2-terminal residues and replacement by nonpolar Ala of polar residues Ser and Thr found at position ␣131(H14) in human and X. leavis Hbs, respectively. The data indicate adaptive significance of ␣-chain chloride-binding sites in amphibians, in contrast to human Hb where chloride appears mainly to bind in the cavity between the ␤-chains. The findings are discussed in relation to other strategies for high-altitude adaptations in amphibians.amphibians; chloride binding; hypoxia; organic phosphates; oxygen transport HOW IS OXYGEN TRANSPORT to metabolizing tissues secured at high altitude? In contrast to intensive investigations in birds and mammals (7,39,59), the molecular strategies for O 2 transport in high-altitude ectothermic vertebrates remain unexplored, despite greater variations in environmental conditions (temperature, pH, O 2 tension, etc.) and lesser capacities for homeostatic regulation of internal physical and chemical conditions compared with homeothermic vertebrates and a long-standing interest in high-altitude aquatic amphibians (1, 24).The anuran genus Telmatobius (that variously is referred to as frogs or toads) occurs in the Andes mountains at altitudes from 2,000 to over 4,000 m (14) where aerial O 2 tensions fall from ϳ159 mmHg at sea level to ϳ92 mmHg. The hypoxic stress is compounded in aquatic species, particularly at night when photosynthetic activity in the ponds ceases (21). T. culeus found in Lake Titicaca at 3,812 m has reduced, poorly developed lungs but exhibits compensatory physiological and behavioral adaptations (24) that include an "oversized," folded skin, which is penetrated by cutaneous capillaries and ventilated by "bobbing" behavior under hypoxia, and small erythrocytes and higher erythrocyte counts, blood-O 2 affinities, and O 2 -carrying capacities than anurans living at sea level (24). Subspecies of Bufo spinulosus living at sea level and at 3,100 to 4,100 m in the Andes analogously exhibit increasing blood-O 2 affinities with altitude (43).The O 2 affinity of blood is a product of the intrinsic O 2 affinity of the Hb molecules and the erythrocytic effectors that modulate Hb-O 2 affinity. Compared with mammals that use 2,3-diphosphoglycerate (DPG) and fish that use ATP (often in conjunction with the more potent effector guanosine triphosphate) (60) as organic O 2 -affinity modulat...

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Enthalpic consequences of reduced chloride binding in Andean frog (Telmatobius peruvianus) hemoglobin

Weber

2014

J Comp Physiol B

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Based on the exothermic nature of heme oxygenation, the O2 affinity of hemoglobin (Hb) decreases with increasing temperature, which may be physiologically advantageous in augmenting O2 unloading from blood in warm tissues with elevated metabolic rates. This negative oxygenation enthalpy (∆H (O)) may, however, become maladaptive, as in cold-tolerant ungulates where it may hamper O2 unloading in cold extremities and commonly is mitigated by an 'additional' chloride-binding site that decreases the temperature effect by increasing the endothermic release of Cl(-) ions upon O2 binding. Since no previous studies have focused on the consequences of reduced Cl(-) binding, I report and compare the enthalpic effects of chloride ions and the allosteric effector, ATP, on Hbs of the high-altitude aquatic Andean frog Telmatobius peruvianus that lacks the α-chain chloride-binding site, and the lowland (sub-)tropical frog Xenopus laevis that has retained this site and exhibits high chloride sensitivity. In contrast to Xenopus, Telmatobius Hb exhibits high temperature sensitivity (high negative ∆H') in the presence of Cl(-) ions, supporting the inverse relationship between the number of Cl(-)-binding sites and temperature sensitivity, and extending it to ectothermic vertebrates. The radically reduced chloride binding in Telmatobius Hb permits assessment of the enthalpy of ATP binding [(∆H' ≈ -62 kJ (mol ATP)(-1) at pH 7.0]-which contrasts sharply with previously reported increases in temperature sensitivity by ATP in toad (Bufo bufo) Hb. The high temperature sensitivity associated with decreased chloride binding and low phosphate sensitivity of Telmatobius Hb likely promotes cutaneous O2 uptake in cold, high-altitude ponds and streams.

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Isohemoglobin Differentiation in the Bimodal-breathing Amazon Catfish Hoplosternum littorale

Abstract: The bimodal gill(water)/gut(air)-breathing Amazonian catfish Hoplosternum littorale that frequents hypoxic habitats uses "mammalian" 2,3-diphosphoglycerate (DPG) in addition to "piscine" ATP and GTP

Cited by 46 publications

References 56 publications

Gene Duplication and the Evolution of Hemoglobin Isoform Differentiation in Birds

Gene Duplication and the Evolution of Hemoglobin Isoform Differentiation in Birds

Novel mechanism for high-altitude adaptation in hemoglobin of the Andean frogTelmatobius peruvianus

Enthalpic consequences of reduced chloride binding in Andean frog (Telmatobius peruvianus) hemoglobin

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