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- Strobel, Anneli, et al.
(författare)
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Influence of Temperature, Hypercapnia, and Development on the Relative Expression of Different Hemocyanin Isoforms in the Common Cuttlefish Sepia officinalis
- 2012
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Ingår i: Journal of Experimental Zoology Part A. - : Wiley. - 1932-5231. ; 317:8, s. 511-523
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Tidskriftsartikel (refereegranskat)abstract
- The cuttlefish Sepia officinalis expresses several hemocyanin isoforms with potentially different pH optima, indicating their reliance on efficient pH regulation in the blood. Ongoing ocean warming and acidification could influence the oxygen-binding properties of respiratory pigments in ectothermic marine invertebrates. This study examined whether S. officinalis differentially expresses individual hemocyanin isoforms to maintain optimal oxygen transport during development and acclimation to elevated seawater pCO 2 and temperature. Using quantitative PCR, we measured relative mRNA expression levels of three different hemocyanin isoforms in several ontogenetic stages (embryos, hatchlings, juveniles, and adults), under different temperatures and elevated seawater pCO 2. Our results indicate moderately altered hemocyanin expression in all embryonic stages acclimated to higher pCO 2, while hemocyanin expression in hatchlings and juveniles remained unaffected. During the course of development, total hemocyanin expression increased independently of pCO 2 or thermal acclimation status. Expression of isoform 3 is reported for the first time in a cephalopod in this study and was found to be generally low but highest in the embryonic stages (0.2% of total expression). Despite variable hemocyanin expression, hemolymph total protein concentrations remained constant in the experimental groups. Our data provide first evidence that ontogeny has a stronger influence on hemocyanin isoform expression than the environmental conditions chosen, and they suggest that hemocyanin protein abundance in response to thermal acclimation is regulated by post-transcriptional/translational rather than by transcriptional modifications.
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- Wirths, Oliver, et al.
(författare)
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Pyroglutamate Abeta pathology in APP/PS1KI mice, sporadic and familial Alzheimer's disease cases
- 2010
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Ingår i: Journal of neural transmission. - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 117:1, s. 85-96
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Tidskriftsartikel (refereegranskat)abstract
- The presence of Abeta(pE3) (N-terminal truncated Abeta starting with pyroglutamate) in Alzheimer's disease (AD) has received considerable attention since the discovery that this peptide represents a dominant fraction of Abeta peptides in senile plaques of AD brains. This was later confirmed by other reports investigating AD and Down's syndrome postmortem brain tissue. Importantly, Abeta(pE3) has a higher aggregation propensity, and stability, and shows an increased toxicity compared to full-length Abeta. We have recently shown that intraneuronal accumulation of Abeta(pE3) peptides induces a severe neuron loss and an associated neurological phenotype in the TBA2 mouse model for AD. Given the increasing interest in Abeta(pE3), we have generated two novel monoclonal antibodies which were characterized as highly specific for Abeta(pE3) peptides and herein used to analyze plaque deposition in APP/PS1KI mice, an AD model with severe neuron loss and learning deficits. This was compared with the plaque pattern present in brain tissue from sporadic and familial AD cases. Abundant plaques positive for Abeta(pE3) were present in patients with sporadic AD and familial AD including those carrying mutations in APP (arctic and Swedish) and PS1. Interestingly, in APP/PS1KI mice we observed a continuous increase in Abeta(pE3) plaque load with increasing age, while the density for Abeta(1-x ) plaques declined with aging. We therefore assume that, in particular, the peptides starting with position 1 of Abeta are N-truncated as disease progresses, and that, Abeta(pE3) positive plaques are resistant to age-dependent degradation likely due to their high stability and propensity to aggregate.
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