Bonnie J. Davis

Hemoglobin heterogeneity in Amazonian fishes

Abstract 1. The hemoglobin patterns of hemolysates from the lungfish,Lepidosiren paradoxa, four species of freshwater rays (Potamotrygon), and actinopterygian teleosts from 77 genera have been characterized by polyacrylamide disc gel electrophoresis. 2. These tropical fishes have hemolysates which are as complex as those reported from temperate zone fishes. 3. There are no obvious correlations between hemoglobin multiplicity and the fish behaviour or habitat preference. 4.Potamotrygon has blurred hemoglobin patterns,Lepidosiren shows a single hemoglobin, and the other teleosts show a mean of 4.0 hemoglobin bands per phenotype. 5. Ostariophysan fishes have a lower mean number of bands per phenotype than acanthopterygian fishes. 6. Patterns of a single hemoglobin band occurred in 8% of the phenotypes. 7. Two or more hemoglobin phenotypes were found in about 10 species. 8. SDS gel electrophoresis showed the fish hemoglobin chains to have molecular weights comparable to those of human Hb A.

Functional properties of hemoglobins from deep-sea fish: correlations with depth distribution and presence of a swimbladder

The ligand binding properties of the hemoglobins of several deep-sea, bottom-living fish have been examined. These include five species of rattails (Macrouridae) and Antimora rostrata, all of which possess swimbladders, and two unrelated species without swimbladders, Bathysaurus mollis and Alepocephalus sp. All of the hemolysates of these fish exhibited the Root effect with a minimum ligand affinity at about pH 6 in the presence of organic phosphate. Under these conditions the hemolysates from fish which possess swimbladders exhibit two roughly equal populations of heme groups with markedly different ligand affinities. For the deeper-dwelling species the affinities for carbon monoxide differ by some 500-fold, the low-affinity population having a p50(CO) of 100 mmHg at 15 degrees C. This very low affinity is associated with a second-order rate constant for CO combination of the order of 10(3) M-1 X s-1. Those species without swimbladders have hemoglobins which do not have such heterogeneous binding sites, suggesting a relationship between these very-low-affinity heme groups and the pumping of oxygen into a swimbladder at high hydrostatic pressures.

Acclimation to hypoxic water in facultative air-breathing fish: Blood oxygen affinity and allosteric effectors

Abstract 1. Blood oxygen affinities, erythrocytic nucleoside triphosphate concentrations (NTP) and other hematological parameters were measured in facultative air-breathing fish from the Amazon after acclimation to well-aerated (“normoxic”) and hypoxic water ( P O 2 = 125–135 and 20–25 mm, respectively). 2. In the armored catfish Hypostomus sp. and Pterygoplichthys sp., hypoxia induces intermittent surfacing to gulp air and results in lower NTP levels, chiefly through significant decreases in guanosine triphosphate (GTP). The subsequent increases in blood O 2 affinity appear adaptive to lowered time average internal O 2 tensions. No similar changes were seen in the ell Synbranchus which breathes air almost continuously when kept in hypoxic water. 3. The results are discussed in terms of their adaptive significance, and compared with data on temperate fish.

A fetal-maternal shift in the oxygen equilibrium of hemoglobin from the viviparous caecilian,Typhlonectes compressicauda

1. The equilibria and kinetics of oxygen binding by blood and hemoglobin from adult and fetal caecilians,Typhlonectes compressicauda, have been measured. 2. The oxygen affinity of fetal blood is higher than that of adult blood. 3. Electrophoresis of adult and fetal hemoglobins suggests that they may be identical: a major and minor component occurs in each. 4. Adult and fetal hemoglobins have identical oxygen equilibria. Stripped hemoglobins have a high oxygen affinity and no Bohr effect between pH 6.5 and 10.0. An “acid”, reversed Bohr effect is present below pH 6.5. The addition of 1 mM ATP reduces the oxygen affinity markedly and produces a moderate, normal Bohr effect. 5. The major nucleoside triphosphate in fetal and adult erythrocytes is adenosine triphosphate: about 10% of the nucleoside triphosphates is guanosine triphosphate. Adult erythrocytes contain 3 times as much ATP as do the fetal erythrocytes. 6. The fetal to maternal shift in the oxygen equilibrium is mediated entirely by the difference in ATP content of the maternal and fetal red blood cells.

Effects of air-breathing on acid-base balance in the catfish,Hypostomus sp.

1. Armoured catfish (Hypostomus sp.) induced by hypoxic water to breathe air had the same blood pH (7.39 at 30° C) as fish kept in well-aerated water and relying solely on gill ventilation (pH 7.41). 2. CO2 retention occurred (PCO2 increased from 3 to 20 torr) in the hypoxic group indicating reduced aquatic gas exchange, but it was fully compensated by an increase in plasma bicarbonate (from 2 to 13 mmol/l). 3. This pattern of acid-base balance is similar to those found in previous interspecies comparisons of water- and air-breathing vertebrates. 4. The higher plasma bicarbonate of hypoxia-acclimated fish is believed to be beneficial in buffering metabolic acids produced by anaerobic metabolism.

Antigenic relationships among fishes common to the Amazon River basin

Abstract o 1. Utilizing antisera to carp and trout hemoglobins, the hemoglobins of fish common to the Amazon River basin exhibited extensive cross reactions. 2. While no fish hemoglobin precipitated with antiserum to trout 4 (anodal omponent), many hemoglobins precipitated with either antisera to trout 1 (cathodal component) or carp hemoglobins. 3. Several patterns of reactivity could be described among the polydisperse hemoglobins of various species, which were analyzed by the electrophoretic separation of the components and an assessment of the ability of individual components to react with the two types of antisera. 4. Most striking was the different reactivity noted amongst the catfishes where the hemoglobinsof air-breathing catfishes reacted more strongly with anti-trout 1 serum than with anti-carp serum, while the hemoglobins of the water-breathing catfishes behaved in reciprocal fashion.

Properties of hemocyanins isolated from Amazon river arthropods and molluscs

1. Hemocyanins from four organisms inhabiting the Amazon River were isolated and partially characterized. 2. Three arthropodan species (Dilocarcinus pagei cristatus, Silviocarcinus pardalinus andMacrobrachium amazonicum) possess hemocyanins whose subunit structure is remarkably simple. Regular and SDS polyacrylamide disc electrophoresis revealed predominantly single bands and no polymorphisms. 3. Oxygen-binding experiments showed that the three arthropodan hemocyanins possess large positive Bohr effects and pH dependence in the degree of subunit interaction. 4. The hemocyanin of one mollusc,Pila sp., was studied and its subunit size appears to be similar to that of other molluscan hemocyanins, i.e. a polypeptide of mol. wt 400,000. In the hemolymph,Pila hemocyanin probably exists as a mixture of 100 and 124S aggregates. 5. The oxygen binding properties of the large molecules ofPila hemocyanin are notable because of their low cooperativity and lack of a strong pH-dependence.

Effects of sodium chloride and carbon dioxide on oxygen binding byArtemia hemoglobin

SummaryThe effects of both sodium chloride and CO2 on oxygen binding by component II of the hemoglobin fromArtemia franciscana have been determined. Sodium chloride decreases both the oxygen affinity and cooperativity: the Hill coefficient decreases from 2.4 to 1.7 in the presence of 0.5 M NaCl at pH 7.5, 20°C. In contrast, CO2 increases both the oxygen affinity and cooperativity. The effects of both agents are small and increase with the degree of oxygenation.

A precipitin reaction between humanserum and fish hemoglobins

Abstract o 1. A precipitin reaction in agar gel (method of Ouchterlony) was noted between normalhuman serum and certain fish hemoglobins. 2. Evidence was accumulated that the reactant in human serum is the albumin fraction 3. The reaction exhibited considerable specificity in that about half the fish hemoglobins testedprecipitated with human serum and half did not