Haemoglobin and Erythrocyte Potassium Types in Sheep and their Influence on Oxygen Dissociation and Haemoglobin Denaturation

Dawson, Terence J.; Evans, J. V.

doi:10.1071/bi9620371

Cited by 22 publications

(17 citation statements)

References 8 publications

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“…It has been claimed that, on average, HK red cells have a higher dry-matter content and specific gravity than LK-type red cells, but the correlation was only very weak (Mounib & Evans,1g59). In studies using only a few animals, Dawson & Evans (1962) found a significant difference between the two cell types in their oxygen dissociation curves, that for HK lying to the left of that for LK blood. Koch (1963) noticed that in LK-type Merino sheep, a breed noted for having very low redcell potassium levels, the glucose 6-phosphate dehydrogenase values were also lower than in the Southdown breed.…”

Section: ( 5 ) Possible S@ufiance Of Potassium Polymorphismmentioning

confidence: 93%

“…Another speculative suggestion as to a possible adaptive value of the haemoglobin types in sheep was put forward by Manwell & Baker (1970). They argued that since HbB is more easily denatured and dissociated into subunits, and hence is less stable than HbA (Dawson & Evans, 1962;Shreffler & Vinograd, 1962;Breathnach, 1964), sheep with the latter haemoglobin may have some advantage over HbB-type sheep because less of their amino-acid intake and energy production has to be used for maintenance of the circulating haemoglobin levels. Manwell & Baker suggested that, since the PA haemoglobin chain has only two methionine residues and thePC chain none compared with the PB chain which has 3 methionine residues, sheep with the gene for HbA, under normal situations, can spare more methionine for the production of other proteins.…”

Section: ( 5 ) Possible Signijicance Of Haemoglobin Polymorphismmentioning

confidence: 99%

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Genetic Variation in the Sheep Red Blood Cell

Tucker¹

1971

Biological Reviews

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Summary 1. There are 7 well‐established red‐cell antigen (blood group) loci. The R‐O system has 3 phenotypes, R, O and i, identified by the ‘naturally occurring’ antibodies, anti‐R and anti‐O. The R and O substances are also present in soluble form in some body secretions. The expression of R and O is controlled by a dominant gene I, epistatic in effect, at an independent locus from that of R. The systems, A, C, M‐L, B, D and X‐2 are identified by means of ‘immune‐type’ antibodies, and several of the loci have multiple alleles. An isoenzymic form of serum alkaline phosphatase is associated with the R‐O system. The frequency for the genes at the various loci has been determined in a limited number of breeds. 2. Some sheep red cells have high K+ and low Na+ concentrations (HK type, or Key), others have low K+ and high Na+ concentrations (LK type or Kea). Two other rare forms exist; Key type which is HK but with lower than normal K+ values, and Kep type which has approximately equal Na+ and K+ concentrations. The red cells of foetuses and newborn lambs have high K+ levels irrespective of their potassium genotype. HK cells have 3–4 times greater (Na+‐K+)‐activated ATPase activity, a 3–4 times increased rate of active K+ transport and a larger number of ouabain‐binding sites than LK cells. Antigen M is present on homozygous HK and heterozygous LK red cells, and antigen L is present on homozygous and heterozygous LK red cells. Sensitization of LK cells with anti‐L stimulates active K+ transport and ATPase activity and exposes a larger number of ouabain‐binding sites in these cells. Anti‐M has no effect. The red cells of newborn lambs only show weak L and M antigen activity. It is postulated that L antigen inhibits cation transport in LK cells by masking the pump sites on the membrane. Immature red cells in LK‐type sheep have a high rate of active K+ transport and yet have L antigen present. No satisfactory explanation for this has yet been advanced. There is no conclusive evidence that the potassium types have any significance from the point of view of adaptation or sheep breeding. The potassium‐gene frequencies are known for a large number of breeds. 3. Two allelic genes, Hb4 and HbB control 3 haemoglobin phenotypes, A, AB, and B. Foetal haemoglobin (HbF) is present in foetuses and newborn lambs. Sheep with HbA also synthesize small amounts of another haemoglobin (HbC) and under conditions of severe anaemia, synthesis of HbC takes over from that of HbA. No change in HbB is observed in anaemia. A rare haemoglobin (HbD) has been found in 3 Yugoslavian sheep. Hbs A, B, C and F differ in their physicochemical properties; they share the same alpha chains but their non‐alpha chains differ in a number of amino acids. HbD differs from HbA in one amino acid in the alpha chain. Certain genetic aspects are discussed. There is some evidence that sheep with HbA are less fertile than those with HbB. The gene frequencies for Hb are known for a large number of breeds. 4. Two isoenzymic forms of carbonic anhydrase are found in red‐cel...

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Section: ( 5 ) Possible S@ufiance Of Potassium Polymorphismmentioning

confidence: 93%

Section: ( 5 ) Possible Signijicance Of Haemoglobin Polymorphismmentioning

confidence: 99%

Genetic Variation in the Sheep Red Blood Cell

Tucker¹

1971

Biological Reviews

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“…Sheep haemoglobins A and B differ from each other in their oxygen dissociation characteristics, Hb A having a greater affinity for oxygen than Hb B (Huisman, van Vliet, and Sebens 1958;Dawson and Evans 1962). Addition of GSH to human blood shifts the oxygen dissociation curve to the right, i.e.…”

Section: (E) Relationships Between Erythrocyte Gsh Levels and The Parmentioning

confidence: 99%

Erythrocyte Glutathione Polymorphism in Sheep

Agar¹,

Roberts²,

Evans³

1972

Aust. Jnl. Of Bio. Sci.

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Reduced glutathione (GSH) levels of erythrocytes were determined in five sheep breeds. The Merino breed had a higher incidence of low GSH animals than the other breeds tested. High GSH type animals of the Border Leicester breed had a significantly lower mean GSH level than did higher GSH animals of the other breeds.GSH levels were found to be associated with electrolyte.levels, haemoglobin type, fleece weight, and body weight in Merino sheep.

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“…This type has a slightly lower whole blood oxygen affinity than the high potassium erythrocyte type (Dawson and Evans, 1962). The right common carotid arteries were permanently exteriorized.…”

Section: Methodsmentioning

confidence: 99%

“…In domestic sheep there exist two genetically determined types of haemoglobin (Evans, King, Cohen, Harris and Warren, 1956), which have different oxygen affinities (Huisman, van Vliet and Sebens, 1958;Meschia, Naughton, Battaglia, Hellegers and Barron, 1961;Dawson and Evans, 1962). There are variations in the gene frequencies of these haemoglobins associated with variations in the environment Warren, 1958a, 1958ii;Evans and Blunt, 1961), indicating possible adaptive significance, i.e., sheep possessing one of the haemoglobins may have some form of advantage in certain environments over sheep possessing the other haemoglobin.…”

Section: Introductionmentioning

confidence: 99%

Effect of Anaemia on Oxygen Transport in Sheep With Different Haemoglobin Types

Dawson

Evans

1967

Aust J Exp Biol Med

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Summary The effect of chronic anaemia on oxygen transport in sheep with genetically different haemoglobins was studied. Measurements were made before and after the haematocrits of the two types of sheep had been reduced by blood removal to the same low anaemic level. The results showed that sheep with haemoglobin‐A (the haemoglobin with higher oxygen affinity) had a significantly greater cardiac output than sheep with haemoglobin‐B. Most of the difference in cardiac output could be attributed to the poorer ability of the blood of sheep with Hb‐A to liberate oxygen in the tissue capillaries, although there was some difference in oxygen consumption between the two groups. The results were considered with respect to the more complex chronic anaemias which occur under field conditions.

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Haemoglobin and Erythrocyte Potassium Types in Sheep and their Influence on Oxygen Dissociation and Haemoglobin Denaturation

Cited by 22 publications

References 8 publications

Genetic Variation in the Sheep Red Blood Cell

Genetic Variation in the Sheep Red Blood Cell

Erythrocyte Glutathione Polymorphism in Sheep

Effect of Anaemia on Oxygen Transport in Sheep With Different Haemoglobin Types

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