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  • 1
    ISSN: 1432-136X
    Keywords: Crustacea ; Amphipoda ; Haemocyanin ; Temperature sensitivity ; l-Lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of pH, temperature, and l-lactate on the O2 bindign properties of haemocyanin (Hc) from three talitroidean species i.e., the aquatic Apohyale pugettensis, the semi-terrestrial Megalorchestia californiana, and the semi-/euterrestrial Traskorchestia traskiana was studied. The Hc of A. pugettensis was characterized by a higher O2 affinity (and more pronounced Bohr shift) than the Hc of either M. californiana or T. traskiana. Apohyale was the only species that possessed He that was sensitive to temperature change. Resuspending Hc from each of the three species in a stock Ringer's solution (based on the ionic composition of the haemolymph of T. traskiana) showed that the persistence of the difference in Bohr shift between Apohyale and the other two species was due to differences in the haemocyanins themselves and not attributable to their respective ionic environments. An inverse relationship was found between the cooperativity (n 50) and pH of Hc from T. traskiana and A. pugettensis but not for M. californiana. In each case adding l-lactate increased Hc O2 affinity, but this was most pronounced for A. pugettensis.
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  • 2
    ISSN: 1432-136X
    Keywords: Crustacea ; Amphipoda ; Haemocyanin ; O2 transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Haemolymph PO2 and pH of two amphipod species, Apohyale pugettensis (aquatic) and Megalorchestia californiana (semi-terrestrial) in vivo were examined during immersion and emersion at 15 and 25°C, and also after activity in air at 15°C. For M. californiana arterial O2 tensions were higher in air than in water. This situation was reversed in A. pugettensis, although all O2 tensions measured for both species were comparatively high. No arterial-venous PO2 difference was apparent in the haemolymph of quiescent M. californiana. Haemocyanin (Hc) was 100% saturated in vivo only in the following; A. pugettensis in water (15 and 25°C) and air (15°C), and M. californiana in air (15°C). The Hc of both species becomes important in O2 transport during activity; under such circumstances the haemolymph of M. californiana delivered more O2 to the tissues than did that of A. pugettensis, despite the greater O2 content of the latter. The animals studied here may exhibit a stage (size class?) where cutaneous gas exchange is sufficient for resting aerobic metabolism while specialized respiratory carriers (and respiratory structures) are important in meeting the increased aerobic demands of activity or environmental stress.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 377 (1998), S. 201-204 
    ISSN: 1573-5117
    Keywords: hypogean ; epigean ; reduced metabolism ; oxygen uptake ; effect of feeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The epigean amphipod Gammarus lacustris possessed a rate of oxygen uptake (MO2) three times greater that of the hypogean amphipod Stygobromus sp. While much of the difference between these two species could be attributed to different feeding regimes, the hypogean amphipod still exhibited a lower rate of metabolism than the epigean species. This suggests that there can be both a genetic and an environmental (reduced food availability and/or hypoxia) component to the reduced metabolism characteristic of many hypogean animals. The results of this study have re-emphasised the pitfall of making species comparisons without knowledge of the extent of physiological variation within a species.
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  • 4
    ISSN: 1432-136X
    Keywords: Amphipoda ; Crustacea ; Haemocyanin ; Freezing ; Inorganic effectors ; Urate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of variations in [K], [Ca], [Mg], [NaCl], and [urate] on the in vitro O2 binding properties of haemocyanin (Hc) from three talitroidean species, viz. the aquatic Apohyale pugettensis, the semi-terrestrial Megalorchestia californiana, and the semi-/euterrestrial Traskorchestia traskiana were studied. Freezing altered the cooperativity of Hc from A. pugettensis and M. californiana but not T. traskiana. Variations in [NaCl], [K], and [Mg] had no effect on cither O2 affinity or cooperativity of the Hc except for A. pugettensis Hc where an increase in [Mg] resulted in an increase in both O2 affinity and cooperativity. Increasing [Ca] or [urate] increased O2 affinity of both A. pugettensis and M. californiana but not T. traskiana Hc. These effects were most marked in A. pugettensis. The results suggest a negative correlation between sensitivity to Hc effectors and the degree of terrestrial adaptation of a particular amphipod species.
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  • 5
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Specimens of the edible crab Cancer pagurus (L.) collected in the Skagerrak, Denmark, between June and August 1990 were examined in the laboratory. Impairment of respiratory function after pre-exposure (7 d) to sub-lethal concentrations of Cu and Zn (0.4 mg l-1) was only detectable during hypoxic exposure [PO2 (partial pressure of oxygen) =60 torr]. This was indicated by a decrease in the transfer factor (TO2), due principally to an increase in the PO2 differential across the gills. Cu and Zn exposure did not cause significant changes in ventilation or perfusion although there was some indication that cardiac output may increase in respiratory-impaired individuals. After 28 d exposure no difference was noted in the respiratory responses to hypoxia of treated and untreated crabs. It is concluded that respiratory impairment was due to an increase in the diffusion barrier thickness at the gills and that this was reversible even during continued exposure to trace metal contamination.
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