226 research outputs found

    Carryover effects of environmental stressors influence the life performance of brown trout

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    Carryover effects of environmental stressors occur when experiences of the environment in earlier life stages or seasons influence the performance of individuals later in life. These can be especially critical for species that have diverse developmental transition periods in their life cycle, such as salmonid fish. Sublethal changes in metabolism, size, or growth experienced in early life stages may have a long-lasting effect on the subsequent life performance of these species, but very few studies have formally tested these changes in relation to environmental stressors. Here, we investigated whether different types of fine sediment result in carryover effects that change the life performance of migratory brown trout. First, we manipulated the early habitat conditions of brown trout through the life stages from egg to fry by incubating them in varying substrate treatments (i.e., gravel without added sediment, gravel with added fine sand, and gravel with added organic matter). Exposure to fine sediment during early development had serious effects on the metabolism, size, escape responses, timing of emergence, and potential survival of early life stages. These carryover effects were persistent and remained present over the critical life shift from relying on parentally provided resources as immobile eggs to independent exogenous feeding as parr. Second, fish were relocated as parr to either their original or different treatment environments and their metabolism, size, and growth were reanalyzed. The effects of environmental stress were observed later in their life cycle when fry from the gravel treatment were relocated to sand or organic-rich treatments. These were found to be significantly smaller in size and had a higher metabolic rate than fry maintained in their original treatment environment. Together, our study experimentally demonstrated that the carryover effects of environmental stressors experienced in early stages may influence the fitness outcomes of migratory fish later in life. We suggest that sublethal environmental stressors should be better considered in restoration schemes and management strategies to reverse the current trend of declining salmonid populations

    Comparison of Migratory and Resident Populations of Brown Trout Reveals Candidate Genes for Migration Tendency

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    Candidate genes associated with migration have been identified in multiple taxa: including salmonids, many of whom perform migrations requiring a series of physiological changes associated with the freshwater-saltwater transition. We screened over 5,500 SNPs for signatures of selection related to migratory behavior of brown trout Salmo trutta by focusing on ten differentially migrating freshwater populations from two watersheds (the Koutajoki and the Oulujoki). We found eight outlier SNPs potentially associated with migratory versus resident life history using multiple (>= 3) outlier detection approaches. Comparison of three migratory versus resident population pairs in the Koutajoki watershed revealed seven outlier SNPs, of which three mapped close to genes ZNF665-like, GRM4-like, and PCDH8-like that have been previously associated with migration and smoltification in salmonids. Two outlier SNPs mapped to genes involved in mucus secretion (ST3GAL1-like) and osmoregulation (C14orf37-like). The last two strongly supported outlier SNPs mapped to thermally induced genes (FNTA1-like, FAM134C-like). Within the Oulujoki, the only consistent outlier SNP mapped close to a gene (EZH2) that is associated with compensatory growth in fasted trout. Our results suggest that a relatively small yet common set of genes responsible for physiological functions associated with resident and migratory life histories is evolutionarily conserved

    Recurrent hospitalizations are associated with increased mortality across the ejection fraction range in heart failure

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    Aims The proportion of patients hospitalized for heart failure (HF) with preserved left ventricular ejection fraction (LVEF) is rising, but no approved treatment exists, in part owing to incomplete characterization of this particular HF phenotype. In order to better define the characteristics of HF phenotypes in Finland, a large cohort with 12 years' follow-up time was analysed.Methods and results Patients diagnosed between 2005 and 2017 at the Hospital District of Southwest Finland were stratified according to LVEF measure and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. For this retrospective registry study, previously diagnosed HF patients were defined as follows: patients with reduced ejection fraction (HFrEF; LVEF 40-50% and NT-proBNP >= 125 pg/ml; n = 1468), and preserved ejection fraction (HFpEF; LVEF > 50% and NT-proBNP >= 125 pg/ml; n = 3122) and followed up for 15 022, 4962, and 10 097 patient-years, respectively. Cardiovascular (CV) hospitalization and mortality, influence of pre-selected covariates on hospitalization and mortality, and the proportion of HFpEF and HFmrEF patients with a drop in LVEF to HFrEF phenotype were analysed. All data were extracted from the electronic patient register. HFrEF patients were rehospitalized slightly earlier than HFpEF/HFmrEF patients, but the second, third, and fourth rehospitalization rates did not differ between the subgroups. Female gender and better kidney function were associated with reduced rehospitalizations in HFmrEF and HFrEF, with a non-significant trend in HFpEF. Each additional hospitalization was associated with a two-fold increased risk of death and 2.2- to 2.3-fold increased risk of CV death. All-cause mortality was higher in patients with HFpEF. Although CV mortality was less frequent in HFpEF patients, it was associated with increased NT-proBNP concentrations at index in all patient groups. During the 10 years following the index date, 26% of HFmrEF patients and 10% of HFpEF patients progressed to an HFrEF phenotype.Conclusions These findings suggest that disease progression, in terms of increased frequency of hospitalizations, and the relationship between increased number of hospitalizations and mortality are similar by LVEF phenotypes. These data highlight the importance of effective treatments that can reduce hospitalizations and suggest a role for monitoring NT-proBNP levels in the management of HFpEF patients in particular

    Haplotype analysis in Icelandic and Finnish BRCA2 999del5 breast cancer families

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldThe 999del5 mutation is the single, strong BRCA2 founder mutation in Iceland and the most common BRCA1/2 founder mutation in Finland. To evaluate the origin and time since spreading of the 999del5 mutation in Iceland and in Finland, we constructed haplotypes with polymorphic markers within and flanking the BRCA2 gene in a set of 18 Icelandic and 10 Finnish 999del5 breast cancer families. All Icelandic families analysed shared a common core haplotype of about 1.7 cM. The common ancestors for the Icelandic families studied were estimated to trace back to 340-1000 years, not excluding the possibility that the mutation was brought to Iceland during the settlement of the country. Analysis of the Finnish families revealed two distinct haplotypes. A rare one, found in three families in the old settlement region in southwestern Finland, shared a four-marker (0.5 cM) core haplotype with the Icelandic 999del5 haplotype. A distinct approximately 6 cM haplotype was shared by seven 999del5 Finnish families estimated to have a common ancestry 140-300 years ago. These families cluster in two geographical regions in Finland, in the very same area as those with the rare haplotype and also in the most eastern, late settlement region of Finland. The results may indicate a common ancient origin for the 999del5 mutation in Iceland and in Finland, but distinct mutational events cannot be ruled out. The surprising finding of the same mutation in two completely different haplotypes in a sparsely populated area in Finland may suggest gene conversion
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