The Effects of emersion and hypoxia on the hemolymph acid-base and oxygenation states of the horseshoe crab limulus polyphemus

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dc.contributor.advisorMcMahon, Brian R.
dc.contributor.authorGallagher, Kathleen Lynn
dc.date.accessioned2005-07-21T19:35:58Z
dc.date.available2005-07-21T19:35:58Z
dc.date.issued1989
dc.descriptionBibliography: p. 152-163.en
dc.description.abstractThe effects of both emersion and hypoxic exposure (followed by recovery) on hemolymph acid-base and oxygenation states of the horseshoe crab Limulus polyphemus were examined using both in vitro and in vivo measurements. In vivo studies involved sampling of hemolymph from animals exposed to emersion or hypoxia for 48h, followed by a 48h recovery period. To assess the effects of the repetitive sampling regime, h polyphemus exposed to normoxic seawater were also sampled for a 96h period. The in vitro determinations confirmed the presence of a reversed Bohr effect of comparable magnitude to that previously reported for h polyphemus hemolymph. In agreement with previous measurements made at similar hemolymph c1ยท, cooperativity of o2 binding to hemocyanin (n50 ) was low {1.4). Hemocyanin 02 affinity was, however, higher than previously measured at comparable levels of hemolymph Cl and pH (e.g. P50 = 5 torr at pH 7.6). This series also demonstrated that h polyphemus hemolymph lacks a Haldane effect. The in vivo studies demonstrated that repetitive sampling of hemolymph from animals in normoxic water had little effect on acid-base state. Mean hemolymph pH, Pco2, and Cco2 were stable throughout the sampling regime. Although ventilatory rate remained lower than has previously been reported, a hyperventilatory response was observed in response to sampling. This hyperventilation probably caused the elevation of hemolymph oxygen tensions, most marked during periods of intense sampling. The resultant increase in hemolymph 02 delivery to the tissues during the sampling regime was sufficient to fuel any increase in energy requirements caused by disturbance to the animal; the stable values for hemolymph lactate demonstrated that anaerobic metabolism was not utilized. In contrast to the stability of acid-base state of h polyphemus sampled in normoxic water, animals sampled during emersion demonstrated a marked respiratory acidosis. The elevation of hemolymph CO2 tensions and the decrease in 02 tensions to below 10 torr, both suggested that diffusion of gases across the emersed book gills was limited. The high affinity of h polyphemus hemocyanin for 02, however, allowed similar amounts of o2 to be delivered to the tissues as occurred in animals sampled in normoxic seawater. Although no compensation for acid-base disturbance occurred during emersion, potential hemolymph alkalosis during prolonged moderate hypoxic exposure was averted by elevation of hemolymph bicarbonate concentrations. This compensation prevented a decrease in hemocyanin 02 affinity from occurring via the reversed Bohr effect. Again, delivery of 02 to the tissues was not compromised.
dc.format.extentxiii, 163 leaves ; 30 cm.en
dc.identifier.citationGallagher, K. L. (1989). The Effects of emersion and hypoxia on the hemolymph acid-base and oxygenation states of the horseshoe crab limulus polyphemus (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/15623en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/15623
dc.identifier.isbn031554225Xen
dc.identifier.lccQP 91 G34 1989en
dc.identifier.urihttp://hdl.handle.net/1880/21558
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject.lccQP 91 G34 1989en
dc.subject.lcshHemolymph - Research
dc.subject.lcshAnoxemia
dc.titleThe Effects of emersion and hypoxia on the hemolymph acid-base and oxygenation states of the horseshoe crab limulus polyphemus
dc.typemaster thesis
thesis.degree.disciplineBiological Sciences
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 695 520541656
ucalgary.thesis.notesoffsiteen
ucalgary.thesis.uarcreleaseyen
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