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- Corrigendum: hypoxic induced decrease in oxygen consumption in cuttlefish (Sepia officinalis) Is Associated with minor increases in Mantle Octopine but no changes in markers of protein turnoverPublication . Capaz, Juan Carlos; Tunnah, Louise; MacCormack, Tyson J.; Lamarre, Simon G.; Sykes, António; Driedzic, William R.Corrige o artigo http://hdl.handle.net/10400.1/10858 [This corrects the article DOI: 10.3389/fphys.2017.00344.].
- Reversion to developmental pathways underlies rapid arm regeneration in juvenile European cuttlefish, Sepia officinalis (Linnaeus 1758)Publication . Callaghan, Neal I.; Capaz, Juan Carlos; Lamarre, Simon G.; Bourloutski, Emilie; Oliveira, Ana R.; MacCormack, Tyson J.; Driedzic, William R.; Sykes, António V.Coleoid cephalopods, including the European cuttlefish (Sepia officinalis), possess the remarkable ability to fully regenerate an amputated arm with no apparent fibrosis or loss of function. In model organisms, regeneration usually occurs as the induction of proliferation in differentiated cells. In rare circumstances, regeneration can be the product of naive progenitor cells proliferating and differentiating de novo. In any instance, the immune system is an important factor in the induction of the regenerative response. Although the wound response is well-characterized, little is known about the physiological pathways utilized by cuttlefish to reconstruct a lost arm. In this study, the regenerating arms of juvenile cuttlefish, with or without exposure at the time of injury to sterile bacterial lipopolysaccharide extract to provoke an antipathogenic immune response, were assessed for the transcription of early tissue lineage developmental genes, as well as histological and protein turnover analyses of the resulting regenerative process. The transient upregulation of tissue-specific developmental genes and histological characterization indicated that coleoid arm regeneration is a stepwise process with staged specification of tissues formed de novo, with immune activation potentially affecting the timing but not the result of this process. Together, the data suggest that rather than inducing proliferation of mature cells, developmental pathways are reinstated, and that a pool of naive progenitors at the blastema site forms the basis for this regeneration.
- Hypoxic induced decrease in oxygen consumption in Cuttlefish (Sepia officinalis) is associated with minor increases in mantle octopine but no changes in markers of protein turnoverPublication . Capaz, Juan Carlos; Tunnah, Louise; MacCormack, Tyson J.; Lamarre, Simon G.; Sykes, António V.; Driedzic, William R.The common cuttlefish (Sepia officinalis), a dominant species in the north-east Atlantic ocean and Mediterranean Sea, is potentially subject to hypoxic conditions due to eutrophication of coastal waters and intensive aquaculture. Here we initiate studies on the biochemical response to an anticipated level of hypoxia. Cuttlefish challenged for 1 h at an oxygen level of 50% dissolved oxygen saturation showed a decrease in oxygen consumption of 37% associated with an 85% increase in ventilation rate. Octopine levels were increased to a small but significant level in mantle, whereas there was no change in gill or heart. There were no changes in mantle free glucose or glycogen levels. Similarly, the hypoxic period did not result in changes in HSP70 or polyubiquinated protein levels in mantle, gill, or heart. As such, it appears that although there was a decrease in metabolic rate there was only a minor increase in anaerobic metabolism as evidenced by octopine accumulation and no biochemical changes that are hallmarks of alterations in protein trafficking. Experiments with isolated preparations of mantle, gill, and heart revealed that pharmacological inhibition of protein synthesis could decrease oxygen consumption by 32 to 42% or Na+/K+ ATPase activity by 24 to 54% dependent upon tissue type. We propose that the decrease in whole animal oxygen consumption was potentially the result of controlled decreases in the energy demanding processes of both protein synthesis and Na+/K+ ATPase activity.
- Excitation–contraction coupling reflects the metabolic profile of mantle muscle in young cuttlefishPublication . Callaghan, Neal I.; Ducros, Loïck; Bennett, J. Craig; Capaz, Juan Carlos; Andrade, José Pedro Andrade; Sykes, António; Driedzic, William R.; Lamarre, Simon G.; MacCormack, Tyson J.The mantle muscle of common cuttlefish, Sepia officinalis, is responsible both for high-magnitude and rapid movements for locomotion, as well as sustained ventilation, which require specific metabolic, electrophysiological, and structural organization. Young cuttlefish have a highly oxidative phenotype and a rapid growth rate. Here, we show high rates of oxygen consumption and protein synthesis in juveniles, and these rates decay exponentially over the first few weeks of growth. This is associated with considerable citrate synthase activity (relative to larger cuttlefish) but a lack of glucose metabolism based on zero uptake of glucose by isolated muscle sheets and minimal activity of hexokinase (similar to larger animals). In contrast to glucose metabolism in the heart, glucose metabolism in these muscle sheets was not stimulated by extracellular taurine. Previous research revealed an unusual ion channel complement in mantle myocytes, the most notable feature of which is the lack of a Na+ current during depolarization. Because this adaptation is not consistent across the coleoid clade, we investigated excitation-contraction coupling. Here, mantle energetics and contractility, including the individual components of the total Ca2+ flux driving contraction, were studied. Results indicate that the majority of Ca2+ current underlying contractile stress development capacity in cuttlefish juveniles is not mediated by dihydropyridine-sensitive L-type channels, in contrast to their adult counterparts, and the sarcoplasmic reticulum contributes little to routine contractility. We had previously noted an influence of physiological levels of taurine in limiting cardiac contractility but found no analogous sensitivity in mantle muscle. Finally, transmission electron microscopy of subcellular architecture revealed the presence of sarcoplasmic tubular aggregates, suggesting that oxidative inhibition of sarcoplasmic reticulum function limits its role in this life stage.