Respiration in the Crab, Cancer magister
01 Mar 1970-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology (Springer-Verlag)-Vol. 70, Iss: 1, pp 1-19
TL;DR: Effectiveness in gas exchange and gas transport is remarkably similar in widely diversified respiratory organs of aquatic animals.
Abstract: 1.
Hcy containing blood of the crab, Cancer magister, has a P50 value of 19.6 mm Hg at normal arterial pH (7.7). The Bohr shift (-log P50/pH) was −0.27. Temperature had a marked effect on Oxy-Hcy affinity. Average oxygen capacity was 3.44 vol %.
2.
Oxygen uptake was independent of ambient O2 tension down to about 50 mm Hg and showed an average value of 0.518 ml/kg/mm at 10° C in normoxic water. Oxygen extraction from the respiratory water current averaged 16 %.
3.
Ventilation was measured directly using an electromagnetic flow meter technique. Ventilation values were high compared to other water breathers and averaged 625 ml/kg/min.
4.
Arterial and venous blood were sampled from indwelling catheters in free moving, unrestrained animals. PaO2 averaged 91 mm Hg corresponding to nearly complete O2 saturation while PvO2 averaged 21 mm Hg giving a saturation of about 50 %. During activity both arterial and venous O2 tensions dropped but utilization of circulating O2 increased. The role of Hcy in O2 transport is discussed in the context of earlier studies on crustaceans which differ fundamentally from the results of the present study.
5.
The average cardiac output value calculated from the Fick principle was 29.5 ml/kg/min. The ventilation perfusion ratio was about 22 and somewhat higher than reported for other water breathing animals. The average PO2 gradient from water to blood was 60.5 mm Hg which closely matches values from fishes and the cephalopod Octopus dofleini.
6.
The results are analyzed and compared with similar information on gas exchange in other water breathers. It is concluded that effectiveness in gas exchange and gas transport is remarkably similar in widely diversified respiratory organs of aquatic animals.
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TL;DR: This review presents in depth discussions of all these classes of Cu enzymes and the correlations within and among these classes, as well as the present understanding of the enzymology, kinetics, geometric structures, electronic structures and the reaction mechanisms these have elucidated.
Abstract: Based on its generally accessible I/II redox couple and bioavailability, copper plays a wide variety of roles in nature that mostly involve electron transfer (ET), O2 binding, activation and reduction, NO2− and N2O reduction and substrate activation. Copper sites that perform ET are the mononuclear blue Cu site that has a highly covalent CuII-S(Cys) bond and the binuclear CuA site that has a Cu2S(Cys)2 core with a Cu-Cu bond that keeps the site delocalized (Cu(1.5)2) in its oxidized state. In contrast to inorganic Cu complexes, these metalloprotein sites transfer electrons rapidly often over long distances, as has been previously reviewed.1–4 Blue Cu and CuA sites will only be considered here in their relation to intramolecular ET in multi-center enzymes. The focus of this review is on the Cu enzymes (Figure 1). Many are involved in O2 activation and reduction, which has mostly been thought to involve at least two electrons to overcome spin forbiddenness and the low potential of the one electron reduction to superoxide (Figure 2).5,6 Since the Cu(III) redox state has not been observed in biology, this requires either more than one Cu center or one copper and an additional redox active organic cofactor. The latter is formed in a biogenesis reaction of a residue (Tyr) that is also Cu catalyzed in the first turnover of the protein. Recently, however, there have been a number of enzymes suggested to utilize one Cu to activate O2 by 1e− reduction to form a Cu(II)-O2•− intermediate (an innersphere redox process) and it is important to understand the active site requirements to drive this reaction. The oxidases that catalyze the 4e−reduction of O2 to H2O are unique in that they effectively perform this reaction in one step indicating that the free energy barrier for the second two-electron reduction of the peroxide product of the first two-electron step is very low. In nature this requires either a trinuclear Cu cluster (in the multicopper oxidases) or a Cu/Tyr/Heme Fe cluster (in the cytochrome oxidases). The former accomplishes this with almost no overpotential maximizing its ability to oxidize substrates and its utility in biofuel cells, while the latter class of enzymes uses the excess energy to pump protons for ATP synthesis. In bacterial denitrification, a mononuclear Cu center catalyzes the 1e- reduction of nitrite to NO while a unique µ4S2−Cu4 cluster catalyzes the reduction of N2O to N2 and H2O, a 2e− process yet requiring 4Cu’s. Finally there are now several classes of enzymes that utilize an oxidized Cu(II) center to activate a covalently bound substrate to react with O2.
Figure 1
Copper active sites in biology.
Figure 2
Latimer Diagram for Oxygen Reduction at pH = 7.0 Adapted from References 5 and 6.
This review presents in depth discussions of all these classes of Cu enzymes and the correlations within and among these classes. For each class we review our present understanding of the enzymology, kinetics, geometric structures, electronic structures and the reaction mechanisms these have elucidated. While the emphasis here is on the enzymology, model studies have significantly contributed to our understanding of O2 activation by a number of Cu enzymes and are included in appropriate subsections of this review. In general we will consider how the covalency of a Cu(II)–substrate bond can activate the substrate for its spin forbidden reaction with O2, how in binuclear Cu enzymes the exchange coupling between Cu’s overcomes the spin forbiddenness of O2 binding and controls electron transfer to O2 to direct catalysis either to perform two e− electrophilic aromatic substitution or 1e− H-atom abstraction, the type of oxygen intermediate that is required for H-atom abstraction from the strong C-H bond of methane (104 kcal/mol) and how the trinuclear Cu cluster and the Cu/Tyr/Heme Fe cluster achieve their very low barriers for the reductive cleavage of the O-O bond.
Much of the insight available into these mechanisms in Cu biochemistry has come from the application of a wide range of spectroscopies and the correlation of spectroscopic results to electronic structure calculations. Thus we start with a tutorial on the different spectroscopic methods utilized to study mononuclear and multinuclear Cu enzymes and their correlations to different levels of electronic structure calculations.
1,181 citations
TL;DR: In this article, the combined effects of global climate change and elevated CO 2 concentrations were investigated in the edible crab (Carcus pagurus) during a progressive warming scenario from 10 to 22°C and cooling back to 10°C.
201 citations
TL;DR: The hypothesis that deep-sea animals, which are adapted to a stable environment and exhibit reduced metabolic rates, lack the short-term acid-base capacity to cope with the acute hypercapnic stress that would accompany large-scale CO2 sequestration is rejected.
Abstract: Rising levels of atmospheric carbon dioxide could be curbed by large-scale sequestration of CO2 in the deep sea. Such a solution requires prior assessment of the impact of hypercapnic, acidic sea- water on deep-sea fauna. Laboratory studies were con- ducted to assess the short-term hypercapnic tolerance of the deep-sea Tanner crab Chionoecetes tanneri, col- lected from 1000 m depth in Monterey Canyon off the coast of central California, USA. Hemolymph acid- base parameters were monitored over 24 h of exposure to seawater equilibrated with ~1% CO2 (seawater PCO2 ~6 torr or 0.8 kPa, pH 7.1), and compared with those of the shallow-living Dungeness crab Cancer magister. Short-term hypercapnia-induced acidosis in the he- molymph of Chionoecetes tanneri was almost uncom- pensated, with a net 24 h pH reduction of 0.32 units and a net bicarbonate accumulation of only 3 mM. Under simultaneous hypercapnia and hypoxia, short-term ex- tracellular acidosis in Chionoecetes tanneri was com- pletely uncompensated. In contrast, Cancer magister fully recovered its hemolymph pH over 24 h of hyper- capnic exposure by net accumulation of 12 mM bicar- bonate from the surrounding medium. The data sup- port the hypothesis that deep-sea animals, which are adapted to a stable environment and exhibit reduced metabolic rates, lack the short-term acid-base regula- tory capacity to cope with the acute hypercapnic stress that would accompany large-scale CO2 sequestration. Additionally, the data indicate that sequestration in oxy- gen-poor areas of the ocean would be even more detri- mental to deep-sea fauna.
196 citations
Cites methods from "Respiration in the Crab, Cancer mag..."
...Using the Dungeness crab, Johansen et al. (1970) calculated a Bohr shift that would account for a 50% increase in the hemolymph P50 (hemolymph oxygen tension at which hemocyanin is half-saturated) following a 0.4 unit decrease in hemolymph pH....
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...Our choice of Cancer magister as an experimental species was also influenced by its representation in the existing acid– base, respiratory, and circulatory literature (e.g. Johansen et al. 1970, Airriess & McMahon 1994)....
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References
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TL;DR: Gas exchange in an aquatic environment was compared with that in an aerial environment and hypoxia resulted in a marked decrease in the effectiveness of oxygen uptake by the blood, but had little effect on oxygen removal from the water.
Abstract: 1. The effectiveness of oxygen uptake by the blood of rainbow trout ( Salmo gairdneri ) approaches 100%, whereas that for the removal of oxygen from water was only 11-30%. 2. Most of the carbon dioxide is removed from the blood as it passes through the gills, but the effectiveness of carbon dioxide uptake by water is very low, because of the high capacity of water for carbon dioxide compared with oxygen. 3. Moderate exercise had little effect on the effectiveness of gas exchange across the gills. The increased oxygen uptake was facilitated by an increase in the transfer factor of the gills for oxygen. There were small increases in the capacity-rate ratio of blood to water at the gills during moderate exercise. 4. Hypoxia resulted in a marked decrease in the effectiveness of oxygen uptake by the blood, but had little effect on oxygen removal from the water. Gas exchange was facilitated during hypoxia by an increase in transfer factor of the gills, but hindered by an increasing capacity-rate ratio of blood to water at the gills. 5. Gas exchange in an aquatic environment was compared with that in an aerial environment.
152 citations
131 citations
TL;DR: A review of the literature on the activity and metabolism of poikilothermal animals in different latitudes and a revision of the black basses (Micropterus and Huro).
Abstract: FAINSCHMIDT, O. I. 1936. Ammonia formation in the brains of hibernating animals. Biochimiya, 1:450. Cited from Chem. Abst., 31:3116. FELIN, F. 1940. The seasonal fluctuation of benthic macrofauna and limnetic plankton in Searsville Lake; a contribution to the biology of fluctuating reservoirs. Thesis, Stanford University. FIELD, J., II; BELDING, H. S.; and MARTIN, A. W. 1939. An analysis of the relation between basal metabolism and summated tissue respiration in the rat. I. The post-pubertal albino rat. Jour. Cell. and Comp. Physiol., 14:143. FISKE, C. H., and SUBBAROW, Y. 1929. Phosphocreatine. Jour. Biol. Chem., 81: 629. Fox, H. M., and WINGFIELD, C. A. 1937. The activity and metabolism of poikilothermal animals in different latitudes. Proc. Zo6l. Soc. (London), Ser. A, Part III, p. 275. GRAY, J. 1928. Ciliary movement. Cambridge, England: Cambridge University Press. HEILBRUNN, L. V. 1937. An outline of general physiology. Philadelphia: Saunders. HOAGLAND, H. 1936. Some pacemaker aspects of rhythmic activity in the nervous system. Cold Spring Harbor Symp. Quant. Biol., 4:267. HUBBS, C. L., and BAILEY, B. M. 1940. A revision of the black basses (Micropterus and Huro). Misc. Pub. Mus. Zo6l. Univ. Mich., No. 48. KAHN, I. L., and CHEKOUN, L. 1935. Degagement d'ammoniaque par le cerveau suivant l'6tat d'excitation naturelle. Compt. rend. Acad. sci. Paris, 201:505. KERR, S. W. 1935. Studies on the phosphorous compounds of brain. I. Phosphocreatine. Jour. Biol. Chem., 11o:625. KREBS, H. A. 1935. Metabolism of amino acids. IV. The synthesis of glutamine from glutamic acid and ammonia and the enzymic hydrolysis of glutamine in animal tissues. Biochem. Jour., 29:1951. PAGE, I. H. 1937. Chemistry of the brain. Springfield: Thomas. PALLADIN, A. W., and RASHBA, E. I. Creatine contents of various parts of the brains of vertebrates. Ukrain. Biochem. Zhur., 7:85. Cited from Chem. Abst., 30:5276, 1936. PEMBREY, M. S. 1898. Chapter on \"Animal heat,\" in SCHXFER, E. A., Textbook of physiology, 1:785. Edinburgh.
116 citations
TL;DR: In this article, the respiratory properties of blood and dynamics of gas exchange have been studied in the dogfish Squalus suckleyi, and the affinity of Hb for O2 was not influenced by CO2 (no Bohr effect), nor was there a detectable loss in oxygen capacity (no Root effect).
94 citations