Assessing alternative aquaculture technologies: life cycle assessment of salmonid culture systems in Canada

Keywords: LCA Alternative aquaculture technologies Salmonid culture systems Canadian aquaculture a b s t r a c t This study employed life cycle assessment (LCA) to quantify and compare the potential environmental impacts of culturing salmonids in a conventional marine net-pen system with those of three reportedly environmentally-friendly alternatives; a marine floating bag system; a land-based saltwater flowthrough system; and a land-based freshwater recirculating system. Results of the study indicate that while the use of these closed-containment systems may reduce the local ecological impacts typically associated with net-pen salmon farming, the increase in material and energy demands associated with their use may result in significantly increased contributions to several environmental impacts of global concern, including global warming, non-renewable resource depletion, and acidification. It is recommended that these unanticipated impacts be carefully considered in further assessments of the sustainability of closed-containment systems and in ongoing efforts to develop and employ these technologies on a larger scale

Prion Formation and Polyglutamine Aggregation Are Controlled by Two Classes of Genes

Prions are self-perpetuating aggregated proteins that are not limited to mammalian systems but also exist in lower eukaryotes including yeast. While much work has focused around chaperones involved in prion maintenance, including Hsp104, little is known about factors involved in the appearance of prions. De novo appearance of the [PSI+] prion, which is the aggregated form of the Sup35 protein, is dramatically enhanced by transient overexpression of SUP35 in the presence of the prion form of the Rnq1 protein, [PIN+]. When fused to GFP and overexpressed in [ps−] [PIN+] cells, Sup35 forms fluorescent rings, and cells with these rings bud off [PSI+] daughters. We investigated the effects of over 400 gene deletions on this de novo induction of [PSI+]. Two classes of gene deletions were identified. Class I deletions (bug1Δ, bem1Δ, arf1Δ, and hog1Δ) reduced the efficiency of [PSI+] induction, but formed rings normally. Class II deletions (las17Δ, vps5Δ, and sac6Δ) inhibited both [PSI+] induction and ring formation. Furthermore, class II deletions reduced, while class I deletions enhanced, toxicity associated with the expanded glutamine repeats of the huntingtin protein exon 1 that causes Huntington's disease. This suggests that prion formation and polyglutamine aggregation involve a multi-phase process that can be inhibited at different steps.National Institutes of Health (U.S.) (grant GM56350)National Institutes of Health (U.S.) (NSRA F32 postdoctoral fellowship GM072340)National Institutes of Health (U.S.) (grant GM25874)Howard Hughes Medical Institut

Insights into the function of HDAC3 and NCoR1/NCoR2 co-repressor complex in metabolic diseases

Histone deacetylase 3 (HDAC3) and nuclear receptor co-repressor (NCoR1/2) are epigenetic regulators that play a key role in gene expression and metabolism. HDAC3 is a class I histone deacetylase that functions as a transcriptional co-repressor, modulating gene expression by removing acetyl groups from histones and non-histone proteins. NCoR1, on the other hand, is a transcriptional co-repressor that interacts with nuclear hormone receptors, including peroxisome proliferator-activated receptor gamma (PPARγ) and liver X receptor (LXR), to regulate metabolic gene expression. Recent research has revealed a functional link between HDAC3 and NCoR1 in the regulation of metabolic gene expression. Genetic deletion of HDAC3 in mouse models has been shown to improve glucose intolerance and insulin sensitivity in the liver, skeletal muscle, and adipose tissue. Similarly, genetic deletion of NCoR1 has improved insulin resistance and reduced adiposity in mouse models. Dysregulation of this interaction has been associated with the development of cardio-metabolic diseases such as cardiovascular diseases, obesity and type 2 diabetes, suggesting that targeting this pathway may hold promise for the development of novel therapeutic interventions. In this review, we summarize the current understanding of individual functions of HDAC3 and NCoR1/2 and the co-repressor complex formation (HDAC3/NCoR1/2) in different metabolic tissues. Further studies are needed to thoroughly understand the mechanisms through which HDAC3, and NCoR1/2 govern metabolic processes and the implications for treating metabolic diseases

Climate, Uncertainty and the Pacific Salmon Treaty: Insights on the Harvest Management Game

Pacific Salmon are anadromous fish that cross state and international boundaries in their oceanic migrations. Fish spawned in the rivers of one jurisdiction are vulnerable to harvest in other jurisdictions. The rocky history of attempts by the United States and Canada to cooperatively manage their respective salmon harvests suggests that environmental variability may complicate the management of such shared resources. In recent years, an extended breakdown in cooperation was fueled by strongly divergent trends in Alaskan and southern salmon abundance, and a consequent change in the balance of each nation’s interceptions of salmon spawned in the other nation’s rivers. While several natural and anthropogenic factors contributed to these trends, there is considerable evidence that changing ocean conditions played a significant role. The period of high productivity in Alaska contributed to increased Alaskan interceptions of B.C. salmon at a time when Pacific Northwest coho and chinook could least withstand retaliatory actions on the part of the Canadian fleet. Only recently, has the mounting crisis led to a fundamental shift in the approach taken by the two nations to determine their respective salmon-harvest shares. On June 30, 1999, Canada and the U.S. signed an agreement which, if successfully implemented, may lay the groundwork for a more sustainable cooperative management regime. However, there are many unanswered questions regarding the viability and sustainability of the new Pacific Salmon Treaty Agreement. This paper draws lessons from the recent period of turmoil to identify strengths and weaknesses in the new abundance-based management approach, and to suggest avenues for further negotiations to secure more rational management of Pacific salmon resources

Aggregation of scaffolding protein DISC1 dysregulates phosphodiesterase 4 in Huntington’s disease

Huntington’s disease (HD) is a polyglutamine (polyQ) disease caused by aberrant expansion of the polyQ tract in Huntingtin (HTT). While motor impairment mediated by polyQ-expanded HTT has been intensively studied, molecular mechanisms for nonmotor symptoms in HD, such as psychiatric manifestations, remain elusive. Here we have demonstrated that HTT forms a ternary protein complex with the scaffolding protein DISC1 and cAMP-degrading phosphodiesterase 4 (PDE4) to regulate PDE4 activity. We observed pathological cross-seeding between DISC1 and mutant HTT aggregates in the brains of HD patients as well as in a murine model that recapitulates the polyQ pathology of HD (R6/2 mice). In R6/2 mice, consequent reductions in soluble DISC1 led to dysregulation of DISC1-PDE4 complexes, aberrantly increasing the activity of PDE4. Importantly, exogenous expression of a modified DISC1, which binds to PDE4 but not mutant HTT, normalized PDE4 activity and ameliorated anhedonia in the R6/2 mice. We propose that cross-seeding of mutant HTT and DISC1 and the resultant changes in PDE4 activity may underlie the pathology of a specific subset of mental manifestations of HD, which may provide an insight into molecular signaling in mental illness in general

Commentary: comparing efficiency in aquatic and terrestrial animal production systems

First paragraph: Aquaculture is receiving increased attention from a variety of stakeholders. This is largely due to its current role in the global food system of supplying more than half of the seafood consumed, and also because the industry continues to steadily expand (UN Food and Agriculture Organization 2018). A recent article in Environmental Research Letters, 'Feed conversion efficiency in aquaculture: do we measure it correctly?', by Fry et al (2018a) found that measuring feed conversion efficiency of selected aquatic and terrestrial farmed animals using protein and calorie retention resulted in species comparisons (least to most efficient) and overlap among species dissimilar from comparisons based on widely used weight-based feed conversion ratio (FCR) values. The study prompted spirited discussions among researchers, industry representatives, and others. A group assembled to write a standard rebuttal, but during this process, decided it was best to engage the study's original authors to join the discourse. Through this collaboration, we provide the resultant additional context relevant to the study in order to advance conversations and research on the use of efficiency measures in aquatic and terrestrial animal production systems

Peroxisomal Proteostasis Involves a Lon Family Protein That Functions as Protease and Chaperone

Proteins are subject to continuous quality control for optimal proteostasis. The knowledge of peroxisome quality control systems is still in its infancy. Here we show that peroxisomes contain a member of the Lon family of proteases (Pln). We show that Pln is a heptameric protein and acts as an ATP-fueled protease and chaperone. Hence, Pln is the first chaperone identified in fungal peroxisomes. In cells of a PLN deletion strain peroxisomes contain protein aggregates, a major component of which is catalase-peroxidase. We show that this enzyme is sensitive to oxidative damage. The oxidatively damaged, but not the native protein, is a substrate of the Pln protease. Cells of the pln strain contain enhanced levels of catalase-peroxidase protein but reduced catalase-peroxidase enzyme activities. Together with the observation that Pln has chaperone activity in vitro, our data suggest that catalase-peroxidase aggregates accumulate in peroxisomes of pln cells due to the combined absence of Pln protease and chaperone activities.

Cmr1/WDR76 defines a nuclear genotoxic stress body linking genome integrity and protein quality control

DNA replication stress is a source of genomic instability. Here we identify ​changed mutation rate 1 (​Cmr1) as a factor involved in the response to DNA replication stress in Saccharomyces cerevisiae and show that ​Cmr1—together with ​Mrc1/​Claspin, ​Pph3, the chaperonin containing ​TCP1 (CCT) and 25 other proteins—define a novel intranuclear quality control compartment (INQ) that sequesters misfolded, ubiquitylated and sumoylated proteins in response to genotoxic stress. The diversity of proteins that localize to INQ indicates that other biological processes such as cell cycle progression, chromatin and mitotic spindle organization may also be regulated through INQ. Similar to ​Cmr1, its human orthologue ​WDR76 responds to proteasome inhibition and DNA damage by relocalizing to nuclear foci and physically associating with CCT, suggesting an evolutionarily conserved biological function. We propose that ​Cmr1/​WDR76 plays a role in the recovery from genotoxic stress through regulation of the turnover of sumoylated and phosphorylated proteins