The archaeogastropod mollusc Haliotis iris: tissue and blood metabolites and allosteric regulation of haemocyanin function

2002 ◽  
Vol 205 (2) ◽  
pp. 253-263
Author(s):  
Jane W. Behrens ◽  
John P. Elias ◽  
H. Harry Taylor ◽  
Roy E. Weber
Keyword(s):  
Equilibrium Constants ◽  
Adductor Muscle ◽  
Interactive Effects ◽  
Oxygen Binding ◽  
Binding Properties ◽  
Adductor Muscles ◽  
Short Term Exposure ◽  
O2 Delivery ◽  
O2 Binding

SUMMARY We investigated divalent cation and anaerobic end-product concentrations and the interactive effects of these substances and pH on haemocyanin oxygen-binding (Hc-O2) in the New Zealand abalone Haliotis iris. During 24 h of environmental hypoxia (emersion), d-lactate and tauropine accumulated in the foot and shell adductor muscles and in the haemolymph of the aorta, the pedal sinus and adductor muscle lacunae, whereas l-lactate was not detected. Intramuscular and haemolymph d-lactate concentrations were similar, but tauropine accumulated to much higher levels in muscle tissues. Repeated disturbance and short-term exposure to air over 3 h induced no accumulation of d- or l-lactate and no change in [Ca2+], [Mg2+], pH and O2-binding properties of the native haemolymph. The haemolymph showed a low Hc-O2 affinity, a large reverse Bohr effect and marked cooperativity. Dialysis increased Hc-O2 affinity, obliterated cooperativity and decreased the pH-sensitivity of O2 binding. Replacing Mg2+ and Ca2+ restored the native O2-binding properties and the reverse Bohr shift. l- and d-lactate exerted minor modulatory effects on O2-affinity. At in vivo concentrations of Mg2+ and Ca2+, the cooperativity is dependent largely on Mg2+, which modulates the O2 association equilibrium constants of both the high-affinity (KR) and the low-affinity (KT) states (increasing and decreasing, respectively). This allosteric mechanism contrasts with that encountered in other haemocyanins and haemoglobins. The functional properties of H. iris haemocyanin suggest that high rates of O2 delivery to the tissues are not a priority but are consistent with the provision of a large O2 reserve for facultatively anaerobic tissues during internal hypoxia associated with clamping to the substratum.

Responses to Hypersaline Exposure in the Euryhaline Crayfish PAcifastacus Leniusculus: II. Modulation of Haemocyanin Oxygen Binding In Vitro and In Vivo

1982 ◽  
Vol 99 (1) ◽  
pp. 447-467
Author(s):  
MICHÈLE G. WHEATLY ◽  
B. R. MCMAHON
Keyword(s):  
Salt Effect ◽  
Ionic Composition ◽  
Inorganic Ions ◽  
Pacifastacus Leniusculus ◽  
Oxygen Binding ◽  
Complete Saturation ◽  
O2 Delivery ◽  
O2 Binding

The effect of 48 h of hypersaline exposure (25, 50 and 75% SW) on haemocyanin oxygenation properties in the euryhaline crayfish Pacifastacus leniusculus was investigated in vitro and in vivo. In vitro significant increases in affinity and cooperativity were measured, although the magnitude of the Bohr shift was unaffected. In vitro dialysis of haemolymph against physiological salines of variable ionic composition proved that these changes were only partly attributable to altered levels of haemolymph ions, implicating the existence of modulators other than H+ and inorganic ions, the possible identities of which are discussed. Significant depressions of both pre- and postbranchial oxygen tensions (Pv, Ov, O2 and Pa, Oa, O2) were observed, but O2 delivery was maintained by utilization of the venous reserve and by an increase in haemocyanin O2 affinity. This occurred despite a concomitant acidosis whose effect on O2 affinity was directly opposed by the ‘salt’ effect. Under hypersaline conditions, haemocyanin played an increasingly important role in O2 delivery in vivo. Despite a reduction in the concentration of combined O2 at complete saturation of the pigment (CmaxHCyOHCyO2). indicating lowered haemocyanin concentration, compensatory changes in O2-binding and cardiac output precluded an impairment to O2 transfer. Equilibration at the tissues (Et,Ot,O2) in FW was less effective than at the gills (Eb,Ob,O2 but progressively improved with hypersaline exposure reversing this trend. Although effects of increased salinity on O2 equilibrium characteristics were qualitatively similar in vivo and in vitro, some interesting quantitative differences are discussed.

scholarly journals Haemolymph Acid-Base, Electrolyte and Gas Status during Sustained Voluntary Activity in the Land Hermit Crab (Coenobita Compressus)

1986 ◽  
Vol 125 (1) ◽  
pp. 225-243
Author(s):  
Michéle G. Wheatly ◽  
Brian R. Mcmahon ◽  
Warren W. Burggren ◽  
Alan W. Pinder
Keyword(s):  
Hermit Crab ◽  
Oxygen Binding ◽  
Acid Base Balance ◽  
Acid Base ◽  
Voluntary Activity ◽  
Binding Characteristics ◽  
Base Balance ◽  
External Water ◽  
O2 Delivery

After 3h(50 m) of voluntary walking, the haemolymph pH of the land hermit crab Coenobita compressus (H. Milne Edwards) decreased by 0.4units. This was accompanied by increases in CO2 tension (Pcoco2). bicarbonate (HCO3− + CO32-) and lactate concentrations. The hypercapnic acidosis was partially compensated by metabolic bicarbonate accumulation and an H+ deficit developed. Unloaded crabs accumulated less of a proton load than crabs transporting mollusc shells. During activity, oxygenation of the haemocyanin (HCy) accounted for the release of 0.3 mmol CO2l−1, via the Haldane effect, which was seven times more than in settled crabs. Control acid-base balance was re-established within 1 h of recovery. At this time, acidic equivalents were excreted at a mean flux rate of 5 mequiv kg−1 h−1 into a source of external water. [Na+] and the ratio of [Na+]:[Cl−] increased during exercise. Coenobita haemolymph had a high O2-carrying capacity (CmaxHCyOHCyO2 = l.55 mmol 1−1). HCy oxygen-binding characteristics were typical of other decapods (φ= −0.44), yet no lactate sensitivity was apparent. Settled in vivo values of O2 tension (Poo2) and content (Coo2) were located around the half-saturation tension (P50) of the dissociation curve. During exercise, POO2 increased and an unopposed Bohr shift decreased the O2-binding affinity, thereby reducing postbranchial saturation. Quantitatively, however, compensations in cardiac output (V·b) were more instrumental in increasing the O2 delivery to respiring tissues. During recovery, haemolymph POO2 remained high and the venous reserve doubled.

scholarly journals The ‘natural’ hybrid haemoglobin from mule. Interrelationships with its parent haemoglobins from horse and donkey

1992 ◽  
Vol 282 (2) ◽  
pp. 595-599 ◽  
Author(s):  
S G Condò ◽  
M Coletta ◽  
R Cicchetti ◽  
G Argentin ◽  
P Guerrieri ◽  
...  
Keyword(s):  
Free Energy ◽  
Binding Free Energy ◽  
Binding Mode ◽  
Natural Hybrid ◽  
Binding Properties ◽  
Inositol Hexakisphosphate ◽  
Physiological Conditions ◽  
General Terms ◽  
O2 Binding

The equilibrium O2-binding properties of the hybrid haemoglobin (Hb) present in vivo in erythrocytes from mule and of its parent Hbs from horse and donkey were compared with special reference to the effect of heterotropic ligands such as Cl-, D-glycerate 2,3-bisphosphate (DPG) and inositol hexakisphosphate. All these Hbs display a decreased effect by polyphosphates, confirming that what has been observed for horse Hb [Giardina, Brix, Clementi, Scatena, Nicoletti, Cicchetti, Argentin & Condò (1990) Biochem. J. 266, 897-900] is common to other equine species, at least from a qualitative standpoint. However, different quantitative aspects can be detected, which can be accounted for by a different role for the two types of chain in characterizing the binding free energy for the various heterotropic effectors. In particular, it is shown that the binding mode of DPG and inositol hexakisphosphate displays different features since long-range effects can be observed clearly for inositol hexakisphosphate but not for DPG. In general terms, in spite of a different intrinsic O2 affinity, the modulation of functional properties by third ligands leads these Hbs to behave, under physiological conditions, similarly to human HbA. It might represent an interesting example of how different species with similar functional needs find different ways to produce a similar functional behaviour.

Oxygen binding by single red blood cells from the red-eared turtle Trachemys scripta

2001 ◽  
Vol 90 (5) ◽  
pp. 1679-1684 ◽  
Author(s):  
Sebastian Frische ◽  
Stefano Bruno ◽  
Angela Fago ◽  
Roy E. Weber ◽  
Andrea Mozzarelli
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Oxygen Affinity ◽  
Trachemys Scripta ◽  
Oxygen Binding ◽  
Binding Properties ◽  
Cell Variation ◽  
Insight Into

Oxygen-binding properties of single red blood cells from the red-eared turtle Trachemys scripta were measured by microspectrophotometry to describe the variation in oxygen affinity of red blood cells and to gain insight into the distribution of functionally different hemoglobins among red blood cells. Methodologically, this study represents the first report on the cell-to-cell variation in oxygen-binding properties based on oxygen-binding curves of single vertebrate red blood cells. The cells differed significantly with respect to oxygen affinity. Mean oxygen pressure at half saturation of the cells in a blood sample was found to be 20.1 ± 3.3 (SD) Torr. The distribution of oxygen affinities among red blood cells is unimodal, indicating that the two hemoglobins found in turtle blood are not segregated in distinct cells. Therefore, the functional interaction shown by these hemoglobins in vitro is likely to take place in vivo. The considerable variation in oxygen affinity between individual red blood cells calls for its incorporation in models of tissue oxygenation.

The functioning of the haemocyanin of the terrestrial christmas island red crab gecarcoidea natalis and roles for organic modulators

1998 ◽  
Vol 201 (23) ◽  
pp. 3233-3244 ◽  
Author(s):  
A. M. Adamczewska ◽  
S. Morris
Keyword(s):  
Lactate Concentration ◽  
Specific Effect ◽  
Time Dependent ◽  
Binding Properties ◽  
Christmas Island ◽  
Land Crabs ◽  
Gecarcoidea Natalis ◽  
O2 Binding

Gecarcoidea natalis is a land crab that migrates annually several kilometres to breed. The O2-binding properties of haemocyanin in G. natalis were investigated in vitro to test the idea that the O2-binding properties of the haemocyanin of land crabs are not dependent on circulating modulators and to provide a model of haemocyanin functioning during exercise. The affinity of the haemocyanin for O2 decreased with increasing temperature (change in the heat of oxygenation; capdelta H=-59 kJ mol-1). The haemocyanin of G. natalis apparently differs from that of other terrestrial crabs in showing haemocyanin O2 modulation by both organic and inorganic molecules. Haemocyanin O2-affinity was not affected by Mg2+ but was sensitive to changes in Ca2+ concentration ( capdelta logP50/ capdelta log[Ca]=-0.61, where P50 is the partial pressure of O2 required for half-maximal O2 binding). The Bohr factor was modest ( &phgr;=-0.26+/-0.03, N=4, in whole haemolymph at 25 degreesC) and there was no specific effect of CO2 on the O2-binding properties of the haemocyanin. An increase in urate concentration increased haemocyanin O2-affinity, but the effect was linear ( capdelta logP50/ capdelta [urate]=-0.06) and not logarithmic as is the case in other species. The effect of l-lactate on the haemocyanin O2-affinity in G. natalis was unique among the crustaceans,because an increase in l-lactate concentration decreased the haemocyanin O2-affinity. The effect of l-lactate on haemocyanin O2-affinity ( capdelta logP50/ capdelta log[lactate]) was time-dependent and decreased from a maximum of 0.044 on day 1 to 0.001 after 4 days of storage at 4 degreesC. The presence of an unknown dialysable and unstable factor in the haemolymph is postulated to explain the time-dependent effect of l-lactate on haemocyanin O2-binding properties. Model oxygen equilibrium curves constructed for in vivo conditions showed that the reverse effect of l-lactate was advantageous by decreasing the O2-affinity of the haemocyanin beyond that predicted by the Bohr shift alone and assisted in O2 off-loading at the tissues. This effect of lactate can only provide an advantage if the gas-exchange organs maintain arterial O2 loading and thus is dependent on lung function in land crabs and must have occurred coincident with the evolution of these other features.

Haemoglobin-Oxygen Binding Properties in the Blood of Xenopus Laevis, with Special Reference to the Influences of Aestivation and of Temperature and Salinity Acclimation

1980 ◽  
Vol 86 (1) ◽  
pp. 19-37
Author(s):  
ALFRED JOKUMSEN ◽  
ROY E. WEBER
Keyword(s):  
Xenopus Laevis ◽  
Salt Water ◽  
Oxygen Affinity ◽  
Minor Component ◽  
Blood Levels ◽  
Oxygen Binding ◽  
Binding Properties ◽  
Salinity Acclimation ◽  
High O2 ◽  
O2 Binding

The oxygen equilibrium properties of blood and of solutions of haemoglobin from Xenopus laevis are reported. At pH 7.6 the oxygen affinity of the blood, expressed as half saturation oxygen tension (P50) amounts to 27.0 mm and 13.7 mmHg (3.60 and 1.83 kPa) when measured at 25 and 10 °C, while the Bohr factor (Δlog P50/ΔpH) was −0.40, and the Hill's cooperativity coefficient, n, averaged 2.1. These data reflect an overall heat of oxygenation, ΔH, of −7.9 kcal. mol−1, which decreased to −6.3 kcal. mol−1 when the live animals were acclimated to each measuring temperature. Xenopus blood showed a high O2 capacity (15 vol.%) compared to that of other amphibians. Acclimation to water of increased salinity (12%0), and aestivation, raised blood O2 affinity; at 25 °C and pH 7.6, P50 decreased to 21.1 and 25.2 mmHg (2.81 and 3.36 kPa), respectively. These changes were concomitant with increases in the blood levels of urea. In contrast to NaCl and ATP, urea increased O2 affinity of the purified haemoglobin, suggesting that oxygenationlinked binding to haemoglobin is involved in the modulations of the blood O2 affinity during aestivation and acclimation to salt water. Xenopus haemoglobin consists of two components. The major component is electrophoretically anodal, and has O2 binding properties similar to those of the haemolysate; the minor component is cathodal, and shows extremely low P50, pH sensitivity and cooperativity.

Haemocyanin function in the New Zealand abalones Haliotis iris and H. australis: relationships between oxygen-binding properties, muscle metabolism and habitat

1998 ◽  
Vol 49 (2) ◽  
pp. 143 ◽  
Author(s):  
Rufus M. G. Wells ◽  
John Baldwin ◽  
Scott R. Speed ◽  
Roy E. Weber
Keyword(s):  
Primary Source ◽  
Oxygen Storage ◽  
Oxygen Binding ◽  
Binding Properties ◽  
Muscle Enzyme ◽  
Atp Production ◽  
Muscle Work ◽  
Habitat Differences ◽  
Oxygen Stores ◽  
O2 Binding

Abalone have a well developed capacity for anaerobic metabolism in the pedal musculature, and during exercise the haemolymph oxygen stores may be reserved for more oxygen-dependent tissues. This implies that the haemocyanin-based oxygen transport system is poised towards oxygen storage rather than high rates of oxygen delivery. This proposition was examined by determining O2 -binding properties of haemocyanin from two species of abalone that differ in behaviour and environmental oxygen requirements. Both species showed reversed Bohr and Root effects leading to very high oxygen affinity and reduced cooperativity at low pH. A marked temperature sensitivity of haemocyanin–O2 binding in H. iris (with heat of oxygenation at –55.7 kJ mol-1) impairs oxygen loading above 20˚C and may explain the reduced size and density of populations in warmer northern waters. Muscle enzyme activities indicate low maximum rates of ATP production, with arginine phosphate hydrolysis as the primary source of ATP for elevated levels of muscle work. These data support the hypothesis that oxygen stores support high levels of aerobic muscle work. However, the similarities in enzyme profiles and haemocyanin properties could not be related to behavioural and habitat differences.

scholarly journals Haemoglobin polymorphisms affect the oxygen-binding properties in Atlantic cod populations

2008 ◽  
Vol 276 (1658) ◽  
pp. 833-841 ◽  
Author(s):  
Øivind Andersen ◽  
Ola Frang Wetten ◽  
Maria Cristina De Rosa ◽  
Carl Andre ◽  
Cristiana Carelli Alinovi ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Quaternary Structure ◽  
Atlantic Cod ◽  
Three Dimensional ◽  
Oxygen Affinity ◽  
Oxygen Binding ◽  
Low Oxygen ◽  
Binding Properties ◽  
Important Species ◽  
The North

A major challenge in evolutionary biology is to identify the genes underlying adaptation. The oxygen-transporting haemoglobins directly link external conditions with metabolic needs and therefore represent a unique system for studying environmental effects on molecular evolution. We have discovered two haemoglobin polymorphisms in Atlantic cod populations inhabiting varying temperature and oxygen regimes in the North Atlantic. Three-dimensional modelling of the tetrameric haemoglobin structure demonstrated that the two amino acid replacements Met55β 1 Val and Lys62β 1 Ala are located at crucial positions of the α 1 β 1 subunit interface and haem pocket, respectively. The replacements are proposed to affect the oxygen-binding properties by modifying the haemoglobin quaternary structure and electrostatic feature. Intriguingly, the same molecular mechanism for facilitating oxygen binding is found in avian species adapted to high altitudes, illustrating convergent evolution in water- and air-breathing vertebrates to reduction in environmental oxygen availability. Cod populations inhabiting the cold Arctic waters and the low-oxygen Baltic Sea seem well adapted to these conditions by possessing the high oxygen affinity Val55–Ala62 haplotype, while the temperature-insensitive Met55–Lys62 haplotype predominates in the southern populations. The distinct distributions of the functionally different haemoglobin variants indicate that the present biogeography of this ecologically and economically important species might be seriously affected by global warming.

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