Different Relationship between hsp70 mRNA and hsp70 Levels in the Heat Shock Response of Two Salmonids with Dissimilar Temperature Preference

The heat shock response (HSR) refers to the rapid production of heat shock proteins (hsps) in response to a sudden increase in temperature. Its regulation by heat shock factors is a good example of how gene expression is transcriptionally regulated by environmental stresses. In contrast, little is known about post-transcriptional regulation of the response. The heat shock response is often used to characterize the temperature tolerance of species with the rationale that whenever the response sets on, a species is approaching its lethal temperature. It has commonly been considered that an increase in hsp mRNA gives an accurate indication that the same happens to the protein level, but this need not be the case. With climate change, understanding the effects of temperature on gene expression of especially polar organisms has become imperative to evaluate how both biodiversity and commercially important species respond, since temperature increases are expected to be largest in polar areas. Here we studied the HSR of two phylogenetically related Arctic species, which differ in their temperature tolerance with Arctic charr having lower maximally tolerated temperature than Atlantic salmon. Arctic charr acclimated to 15 degrees C and exposed to 7 degrees C temperature increase for 30 min showed both an increase in hsp70 mRNA and hsp70 whereas in salmon only hsp70 mRNA increased. Our results indicate that the temperature for transcriptional induction of hsp can be different from the one required for a measurable change in inducible hsp level. The species with lower temperature tolerance, Arctic charr, are experiencing temperature stress already at the higher acclimation temperature, 15 degrees C, as their hsp70 mRNA and hsp70 levels were higher, and they grow less than fish at 8 degrees C (whereas for salmon the opposite is true). Consequently, charr experience more drastic heat shock than salmon. Although further studies are needed to establish the temperature range and length of exposure where hsp mRNA and hsp level are disconnected, the observation suggests that by measuring both hsp mRNA and hsp level, one can evaluate if a species is approaching the higher end of its temperature tolerance, and thus evaluate the vulnerability of an organism to the challenges imposed by elevated water temperature

Association Mapping Based on a Common-Garden Migration Experiment Reveals Candidate Genes for Migration Tendency in Brown Trout

A better understanding of the environmental and genetic contribution to migratory behavior and the evolution of traits linked to migration is crucial for fish conservation and fisheries management. Up to date, a few genes with unequivocal influence on the adoption of alternative migration strategies have been identified in salmonids. Here, we used a common garden set-up to measure individual migration distances of generally highly polymorphic brown trout Salmo trutta from two populations. Fish from the assumedly resident population showed clearly shorter migration distances than the fish from the assumed migratory population at the ages of 2 and 3 years. By using two alternative analytical pipelines with 22186 and 18264 SNPs obtained through RAD-sequencing, we searched for associations between individual migration distance, and both called genotypes and genotype probabilities. None of the SNPs showed statistically significant individual effects on migration after correction for multiple testing. By choosing a less stringent threshold, defined as an overlap of the top 0.1% SNPs identified by the analytical pipelines, GAPIT and Angsd, we identified eight candidate genes that are potentially linked to individual migration distance. While our results demonstrate large individual and population level differences in migration distances, the detected genetic associations were weak suggesting that migration traits likely have multigenic control

Reliability assessment for medium voltage electrical network : a case study within Eskom distribution

Abstract: In recent years electricity supply has played a very crucial part in people’s lives. However, just having access to electricity is not sufficient; the reliability of electricity supply is also important. In Africa the serious effect of an unreliable power supply is a prominent concern within electrical distribution networks. Outages in the Eskom distribution network accounted for the significant majority of the total outage duration experienced by Eskom Distribution customers. Distribution network systems constitute the greatest risk to the interruptions of electrical power supply; as it is still liable for more than 80% of the customer reliability issues, with the majority of the faults (70%) occurring on the Medium Voltage (MV) networks. As a result, this research study will identify, define, and quantify factors that lead to poor reliability of distribution networks, and, from the findings, alternative solutions will be proposed and discussed, based on the findings of the study. This is intended to assist electrical utilities effectively to investigate the affected network, and to be able to apply strategic reliability improvement plans to achieve optimal performance. The research methodology used to obtain and analyse the data during the research study consists of literature review and a qualitative approach. In order to conduct a full study of the research, the strategy used was a case study. The research findings within Eskom’s distribution network found that the reliability performance is poor due to defective equipment failures, overhead power line problems, maintenance or construction related failures, fuse failures, unit equipment problems and cable theft. Defective equipment posed the highest risk - particularly the cable network. Several solutions were proposed to improve the reliability of Eskom’s distribution, including investments information technology systems, smart grid technologies, capital, operational and maintenance strategies and reliability improvement strategies for defective equipment, overhead power line, fuse, unit equipment and cable theft was discussed. By applying these mitigation strategies and focusing on limiting the entire 85% impact presented by failure root causes, the power cut can be reduced from 18.747 hours to 2.75 hours. Meaning an 85% reliability improvement within Taunus’ distribution supply area in Eskom’s distribution.M.Phil. (Engineering Management

Supplemental table 2 from Immune responses in hibernating little brown myotis (<i>Myotis lucifugus</i>) with white-nose syndrome

Linear mixed model table for the February (post-hibernation) anti-Pd titer and relative mRNA expression of cytokine genes with Type II Wald chisquare tests (package car). Models were fit by maximum likelihood using function lmer in R. Significant effects are shown in bold

Supplemental table 1 from Immune responses in hibernating little brown myotis (<i>Myotis lucifugus</i>) with white-nose syndrome

Table of alternative models for the post-hibernation titer and relative mRNA expression of cytokine genes including post-hibernation SMI and time to euthanasia as covariates. Type II sums of squares were obtained with function Anova from package car, and estimates and standard errors for the main effects with function lm in R. Effects that were not inluded in the final models are shown in parentheses. Significant effects (p<0.05) are shown in bold