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Chemotaxonomic biomarkers are needed to monitor and evaluate the nutritional quality of phytoplankton communities. The biomolecules produced by different phytoplankton species do not always follow genetic phylogeny. Therefore, we analyzed fatty acids, sterols, and carotenoids from 57 freshwater phytoplankton strains to evaluate the usability of these biomolecules as chemotaxonomic biomarkers. We found 29 fatty acids, 34 sterols, and 26 carotenoids in our samples. The strains were grouped into cryptomonads, cyanobacteria, diatoms, dinoflagellates, golden algae, green algae, and raphidophytes, and the phytoplankton group explained 61%, 54%, and 89% of the variability of fatty acids, sterols, and carotenoids, respectively. Fatty acid and carotenoid profiles distinguished most phytoplankton groups, but not flawlessly. For example, fatty acids could not distinguish golden algae and cryptomonads, whereas carotenoids did not separate diatoms and golden algae. The sterol composition was heterogeneous but seemed to be useful for distinguishing different genera within a phytoplankton group. The chemotaxonomy biomarkers yielded optimal genetic phylogeny when the fatty acids, sterols, and carotenoids were used together in multivariate statistical analysis. Our results suggest that the accuracy of phytoplankton composition modeling could be enhanced by combining these three biomolecule groups.

Temperature increases driven by climate change are expected to decrease the availability of polyunsaturated fatty acids in lakes worldwide. Nevertheless, a comprehensive understanding of the joint effects of lake trophic status, nutrient dynamics and warming on the availability of these biomolecules is lacking. Here, we conducted a laboratory experiment to study how warming (18–23°C) interacts with phosphorus (0.65–2.58 μM) to affect phytoplankton growth and their production of polyunsaturated fatty acids. We included 10 species belonging to the groups diatoms, golden algae, cyanobacteria, green algae, cryptophytes and dinoflagellates. Our results show that both temperature and phosphorus will boost phytoplankton growth, especially stimulating certain cyanobacteria species (Microcystis sp.). Temperature and phosphorus had opposing effects on polyunsaturated fatty acid proportion, but responses are largely dependent on species. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) synthesizing species did not clearly support the idea that warming decreases the production or content of these essential polyunsaturated fatty acids. Our results suggest that warming may have different effects on the polyunsaturated fatty acid availability in lakes with different nutrient levels, and that different species within the same phytoplankton group can have contrasting responses to warming. Therefore, we conclude that future production of EPA and DHA is mainly determined by species composition. peerReviewed

Light availability is the main regulator of primary production, shaping photosynthetic communities and their production of ecologically important biomolecules. In freshwater ecosystems, increasing dissolved organic carbon concentrations, commonly known as browning, leads to lower light availability and the proliferation of mixotrophic phytoplankton. Here, a mixotrophic algal species (Cryptomonas sp.) was grown under five increasing dissolved organic carbon concentrations to uncover the plastic responses behind the success of mixotrophs in browning environments and their effect in the availability of nutritionally important biomolecules. In addition to the browning treatments, phototrophic, heterotrophic and mixotrophic growth conditions were used as controls. Despite reduced light availability, browning did not impair algal growth compared to phototrophic conditions. Comparative transcriptomics showed that genes related to photosynthesis were down-regulated, whereas phagotrophy gene categories (phagosome, lysosome, and endocytosis) were up-regulated along the browning gradient. Stable isotope analysis of phospholipid fractions validated these results, highlighting that the studied mixotroph increases its reliance on heterotrophic processes with browning. Metabolic pathway reconstruction using transcriptomic data suggests that organic carbon is acquired through phagotrophy and used to provide energy in conjunction with photosynthesis. Although metabolic responses to browning were observed, essential fatty acid content was similar between treatments while sterol content was slightly higher upon browning. Altogether, our results provide a mechanistic model of how a mixotrophic algae responds to browning and how such responses affect the availability of nutritionally essential biomolecules for higher trophic levels. peerReviewed

Eutrophication and rising water temperature in freshwaters may increase the total production of a lake while simultaneously reducing the nutritional quality of food web components. We evaluated how cyanobacteria blooms, driven by agricultural eutrophication (in eutrophic Lake Köyliöjärvi) or global warming (in mesotrophic Lake Pyhäjärvi), influence the biomass and structure of phytoplankton, zooplankton, and fish communities. In terms of the nutritional value of food web components, we evaluated changes in the ω-3 and ω-6 polyunsaturated fatty acids (PUFA) of phytoplankton and consumers at different trophic levels. Meanwhile, the lakes did not differ in their biomasses of phytoplankton, zooplankton, and fish communities, lake trophic status greatly influenced the community structures. The eutrophic lake, with agricultural eutrophication, had cyanobacteria bloom throughout the summer months whereas cyanobacteria were abundant only occasionally in the mesotrophic lake, mainly in early summer. Phytoplankton community differences at genus level resulted in higher arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) content of seston in the mesotrophic than in the eutrophic lake. This was also reflected in the EPA and DHA content of herbivorous zooplankton (Daphnia and Bosmina) despite more efficient trophic retention of these biomolecules in a eutrophic lake than in the mesotrophic lake zooplankton. Planktivorous juvenile fish (perch and roach) in a eutrophic lake overcame the lower availability of DHA in their prey by more efficient trophic retention and biosynthesis from the precursors. However, the most efficient trophic retention of DHA was found with benthivorous perch which prey contained only a low amount of DHA. Long-term cyanobacterial blooming decreased the nutritional quality of piscivorous perch; however, the difference was much less than previously anticipated. Our result shows that long-term cyanobacteria blooming impacts the structure of plankton and fish communities and lowers the nutritional quality of seston and zooplankton, which, however, is mitigated at upper trophic levels. peerReviewed

1. Organisms at the base of aquatic food webs synthesize essential nutrients, such as omega-3 polyunsaturated fatty acids (n-3 PUFA), which are transferred to consumers at higher trophic levels. Many consumers, requiring n-3 long-chain (LC) PUFA, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have limited ability to biosynthesize them from the essential dietary precursor α-linolenic acid (ALA) and thus rely on dietary provision of LC-PUFA. 2. We investigated LC-PUFA metabolism in freshwater zooplankton using stable hydrogen isotopes (δ2H) of fatty acids as tracers. We conducted feeding experiments with the freshwater keystone grazer Daphnia to quantify changes in the δ2H value of body FA in response to the FA composition of their food and the δ2H value of the ambient water. 3. The isotopic composition of LC-PUFA changed in Daphnia, depending on the integration of 2H from ambient water during de novo synthesis or bioconversion from dietary precursors, allowing us to distinguish dietary from bioconverted EPA in body tissue. We tested the applicability of these laboratory findings in a field setting by analyzing δ2H values of PUFA in primary producers and consumers in eutrophic ponds to track EPA sources of zooplankton. 4. Multilinear regression models that included conversion of ALA to EPA correlated better with zooplankton δ2HEPA than seston δ2HEPA at low dietary EPA supply. 5. This study provides evidence that zooplankton can compensate for low dietary EPA supply by activating LC-PUFA biosynthesis and shows that herbivorous zooplankton play a crucial role in upgrading FA for higher trophic levels during low dietary EPA supply. peerReviewed

We studied how physiologically important long-chain polyunsaturated fatty acids (PUFA) in benthic macroinvertebrates (Asellus aquaticus, Chironomidae, and Oligochaeta) were related to those in periphyton and terrestrial organic matter (tree leaves), collected from littoral areas of 17 boreal lakes that differed in their dissolved organic carbon (DOC) and nutrient (phosphorus and nitrogen) concentrations. We also analyzed fatty acid (FA)-specific stable carbon isotopes (δ13CFA) to investigate the dietary origin (periphyton vs. terrestrial organic matter) of PUFA in the consumers. In contrast to periphyton, terrestrial organic matter was deprived of long-chain PUFA, such as eicosapentaenoic acid (EPA), but rich in short-chain PUFA. The FA composition of macroinvertebrates was primarily taxon-specific despite the large differences in DOC and nutrient concentrations of the lakes. An increase in DOC concentration had a negative impact on the EPA content of Asellus, chironomids, and oligochaetes as well as the total FA content of chironomids and oligochaetes. However, the FA content of macroinvertebrates was not related to lake total phosphorus concentrations, although the total FA and EPA content of periphyton increased with the trophic status of the study lakes. The δ13CPUFA values of macroinvertebrates were positively related with the δ13CPUFA of periphyton and weakly with δ13CPUFA of terrestrial leaf material. The results indicate that EPA in the studied macroinvertebrate taxa was mainly derived from an algal-based diet and not via biosynthesis from allochthonous precursor FA. Thus, macroinvertebrate production in lakes may be limited by the available algae-based food sources. peerReviewed

Concentrations of terrestrial-derived dissolved organic carbon (DOC) in freshwater ecosystems have increased consistently, causing freshwater browning. The mechanisms behind browning are complex, but in forestry-intensive regions browning is accelerated by land drainage. Forestry actions in streamside riparian forests alter canopy shading, which together with browning is expected to exert a complex and largely unpredictable control over key ecosystem functions. We conducted a stream mesocosm experiment with three levels of browning (ambient vs. moderate vs. high, with 2.7 and 5.5-fold increase, respectively, in absorbance) crossed with two levels of riparian shading (70% light reduction vs. open canopy) to explore the individual and combined effects of browning and loss of shading on the quantity (algal biomass) and nutritional quality (polyunsaturated fatty acid and sterol content) of the periphytic biofilm. We also conducted a field survey of differently colored (4.7 to 26.2 mg DOC L-1) streams to provide a ‘reality check’ for our experimental findings. Browning reduced greatly the algal biomass, suppressed the availability of essential polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA), and sterols, but increased the availability of terrestrial-derived long-chain saturated fatty acids (LSAFA). In contrast, loss of shading increased primary productivity, which resulted in elevated sterol and EPA content of the biofilm. The field survey largely repeated the same pattern: biofilm nutritional quality decreased significantly with increasing DOC, as indicated particularly by a decrease of the ω-3:ω-6 ratio and increase in LSAFA content. Algal biomass, in contrast, was mainly controlled by dissolved inorganic nitrogen (DIN) concentration, while DOC concentration was of minor importance. The ongoing browning process is inducing a dramatic reduction in the nutritional quality of the stream biofilm. Such degradation of the major high-quality food source available for stream consumers may reduce the trophic transfer efficiency in stream ecosystems, potentially extending across the stream-forest ecotone. peerReviewed

Many lakes in the northern hemisphere are browning due to increasing concentrations of terrestrial dissolved organic carbon (DOC). The consequences of lake browning to littoral invertebrates, however, are not fully understood. We analyzed community structure and fatty acid (FA) profiles of littoral invertebrates in humic (DOC-rich) and clear-water lakes in Eastern Finland. We found higher abundance of chironomids (Diptera: Chironomidae) in humic compared to clear-water lakes, whereas stoneflies (Plecoptera) and mayflies (Ephemeroptera: Baetidae) were more abundant in clear-water lakes. Taxon explained 65% of the differences in the FA composition of littoral invertebrates. However, the proportion and content of polyunsaturated FAs of several taxa were significantly higher in clear-water lakes compared to humic lakes. Our results reveal differences in both community structure and nutritional quality of littoral invertebrates for fish between humic and clear-water lakes.

Diet quality is crucial for the development of offspring. Here, we examined how the nutritional quality of prey affects somatic growth and the lipid, carbohydrate, protein, amino acid, and polyunsaturated fatty acid content of rainbow trout (Oncorhynchus mykiss) fry using a three-trophic-level experimental setup. Diets differed especially in their content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are physiologically essential polyunsaturated fatty acids for a fish fry. Trout were fed with an artificial diet (fish feed, DHA-rich), marine zooplankton diet (krill/Mysis, DHA-rich), or freshwater zooplankton diet (Daphnia, Cladocera, DHA-deficient). The Daphnia were grown either on a poor, intermediate, or high-quality algal/microbial diet simulating potential changes in the nutritional prey quality (EPA-content). Trout fed with the fish feed or marine zooplankton entirely replaced their muscle tissue composition with compounds of dietary origin. In contrast, fish tissue renewal was only partial in fish fed any Daphnia diet. Furthermore, fish grew five times faster on marine zooplankton than on any of the Daphnia diets. This was mainly explained by the higher dietary contents of arachidonic acid (ARA), EPA, and DHA, but also by the higher content of some amino acids in the marine zooplankton than in the Daphnia diets. Moreover, fatty acid-specific carbon isotopes revealed that trout fry could not biosynthesize ARA, EPA, or DHA efficiently from their precursors. Our results suggest that changes in the zooplankton and macroinvertebrate communities' structure in freshwater habitats from DHA-rich to DHA-poor species may reduce the somatic growth of fish fry. peerReviewed

Ambient light and temperature show extreme seasonal variation in subarctic lakes due to the midnight sun period in summer and cold polar night period in winter. These changes have clear impacts on fish feeding and reproduction cycles, potentially affecting the fatty acid (FA) composition of muscle. Despite extensive research into fish FA over recent decades, we know little about intra‐annual changes of fish FA profile and content. We studied intra‐annual changes in the FA profile (mol%) and content (mg g‐1 dry weight) of sexually mature European whitefish (Coregonus lavaretus) muscle in a large and deep subarctic lake located in northern Fennoscandia. We collected fish, zooplankton, and benthic macroinvertebrate samples during 3 ice‐covered months, including December (during whitefish spawning), and 3 open‐water months. Fish size, age, sex, stomach content and fullness, and gonadosomatic index were also assessed as co‐variates. Whitefish changed diet from benthic macroinvertebrates in winter to zooplankton in summer. Generally, whitefish somatic growth was slow and most energy was used for gonad growth. Zooplankton had higher total content and different profile of FA compared to benthic macroinvertebrates. Increased zooplanktivory in summer was detected with higher α‐linolenic acid (ALA, 18:3n‐3) and stearidonic acid (SDA, 18:4n‐3) percentage and content as well as increased the ratio of polyunsaturated FAs (PUFAs) of n‐3 and n‐6 family (n‐3/n‐6 ratio) in fish muscle. Whitefish gonadal growth and development occur during the summer growing season and continue until the initiation of spawning in early winter. We found that the content of physiologically crucial PUFA, eicosapentaenoic acid (EPA, 20:5n‐3), docosahexaenoic acid (DHA, 22:6n‐3), and arachidonic acid (ARA, 20:4n‐6) decreased by c. 60% between late summer and the spawning period in early winter. After spawning, total FA content of whitefish muscle increased rapidly, reaching the maximum recorded level in mid‐summer. Intra‐annual changes in whitefish muscle FA profiles and contents were modified both by available diet and reproductive phase; however, reproductive physiology was clearly a stronger driver of the changes in muscle FA composition. Results suggest marked changes in intra‐annual FA composition of fish muscle, an important factor that should be considered in future studies and especially in long term monitoring programs. Future studies are needed to determine whether these inter‐annual FA patterns revealed in this study can be extended to different regions and to e.g. adipose or spring spawning species. peerReviewed

The application of exercise-like electrical pulse simulation (EL-EPS) has become a widely used exercise mimetic in vitro. EL-EPS produces similar physiological responses as in vivo exercise, while less is known about the detailed metabolic effects. Routinely, the C2C12 myotubes are cultured in high-glucose medium (4.5 g/L), which may alter EL-EPS responses. In this study, we evaluate the metabolic effects of EL-EPS under the high- and low-glucose (1.0 g/L) conditions to understand how substrate availability affects the myotube response to EL-EPS. The C2C12 myotube, media, and cell-free media metabolites were analyzed using untargeted nuclear magnetic resonance (NMR)-based metabolomics. Furthermore, translational and metabolic changes and possible exerkine effects were analyzed. EL-EPS enhanced substrate utilization as well as production and secretion of lactate, acetate, 3-hydroxybutyrate, and branched-chain fatty acids (BCFAs). The increase in BCFAs correlated with branched-chain amino acids (BCAAs) and BCFAs were strongly decreased when myotubes were cultured without BCAAs suggesting the action of acyl-CoA thioesterases on BCAA catabolites. Notably, not all EL-EPS responses were augmented by high glucose because EL-EPS increased phosphorylated c-Jun N-terminal kinase and interleukin-6 secretion independent of glucose availability. Administration of acetate and EL-EPS conditioned media on HepG2 hepatocytes had no adverse effects on lipolysis or triacylglycerol content. Our results demonstrate that unlike in cell-free media, the C2C12 myotube and media metabolites were affected by EL-EPS, particularly under high-glucose condition suggesting that media composition should be considered in future EL-EPS studies. Furthermore, acetate and BCFAs were identified as putative exerkines warranting more research. NEW & NOTEWORTHY The present study examined for the first time the metabolome of 1) C2C12 myotubes, 2) their growth media, and 3) cell-free media after exercise-like electrical pulse stimulation under distinct nutritional loads. We report that myotubes grown under high-glucose conditions had greater responsiveness to EL-EPS when compared with lower glucose availability conditions and increased media content of acetate and branched-chain fatty acids suggests they might act as putative exerkines warranting further research.

Aerosol particles play significant roles in atmospheric processes but their effects pose large uncertainties in climate predictions. This thesis presents computational and experimental studies of aqueous organic and organic-inorganic solutions that serve as model systems of cloud droplets for better understanding of aerosols and their impact on climate. Carbon and oxygen K-edge X-ray Absorption Spectroscopy (XAS) has been applied in order to study molecular level interactions in aqueous solutions of glyoxal and methylglyoxal and to investigate potential salting effects with addition of inorganic salts to the solutions. The spectra were used for identification of chemical bonds and hydrated forms in the solutions. Carbon K-edge XAS was applied also for the study of binary aqueous solutions comprising surfactantssodium hexanoate and sodium octanoate. The solutions were measured for concentrations of solutes above and below the critical micelle concentration in order to observe the formation of micelles in the solution. In the case of aqueous sodium octanoate changes in the shapes of the spectra with increasing concentrations suggest changes in the chemical environment of the carbon atoms that could possibly be related to micelle formation. COSMOtherm, a software based on COSMO-RS (COnductor like Screening MOdel for Real Solvents), was used to predict solubilities and activity coefficients for C₂–C₁₂ fatty acids with even number of carbon atoms and their sodium salts in binary aqueous solutions and also in ternary solutions, comprising inorganic salts. The computed values indicate that COSMOtherm can be used to provide information about atmospheric organic components of aqueous solutions where experimental data are currently inaccessible. The results of these studies contribute to understanding of cloud microphysics and may be used to improve accuracy of atmospheric model predictions. Abstrakti Aerosolihiukkasilla on merkittävä rooli ilmakehän prosesseissa, mutta niiden vaikutuksiin liittyy suuria epävarmuuksia ilmastoennusteissa. Tässä tutkielmassa on tehty laskennallisia ja kokeellisia tutkimuksia orgaanisten aineiden vesiliuoksista sekä epäorgaanisten suolojen kanssa että ilman niitä. Nämä vesiliuokset ovat mallisysteemejä pilvipisaroille, ja niiden tutkimus auttaa ymmärtämään paremmin aerosoleja ja niiden ilmastovaikutuksista. Hiilen ja hapen K-kuoren röntgenabsorptiospektroskopialla tutkittiin molekyylitason vuorovaikutuksia glyoksaalin ja metyyliglyoksaalin vesiliuoksissa ja näiden orgaanisten aineiden aiheuttamia mahdollisia muutoksia epäorgaanisten suolojen liukoisuuteen. Röntgenabsorptiospektrejä käytettiin kemiallisten sidosten ja hydratoituneiden muotojen tunnistamiseen. Hiilen K-kuoren röntgenabsorptiospektroskopiaa sovellettiin myös pinta-aktiivisia aineita (natriumheksanoaattia ja -oktanoaattia) sisältävien vesiliuosten tutkimiseen. Mittauksia tehtiin pinta-aktiivisten aineiden pitoisuuksille molemmin puolin ns. kriittistä misellikonsentraatiota, jossa misellien muodostumisen tulisi alkaa; natriumoktanoaatin vesiliuoksen tapauksessa spektrien muoto muuttui pitoisuuden kasvaessa, mikä kertoo hiiliatomien kemiallisen ympäristön muutoksesta mahdolliseen misellien muodostumiseen liittyen. COSMOtherm on COSMO-RS-menetelmään (COnductor like Screening MOdel for Real Solvents) perustuva mallinnusohjelma, jota käytettiin ennustamaan parillisen määrän hiiliatomeja sisältävien C₂–C₁₂ rasvahappojen ja niiden natriumsuolojen liukoisuuksia ja aktiivisuusvakioita vesiliuoksissa ja epäorgaanisia suoloja sisältävissä vesiliuoksissa. Laskennalliset tulokset osoittivat, että COSMOtherm voi antaa arvokasta tietoa ilmakehässä esiintyvien orgaanisten aineiden vesiliuoksista, erityisesti tapauksissa, joissa kokeellisia arvoja ei ole vielä saatavilla. Tutkimusten tulokset auttavat ymmärtämään pilvien mikrofysiikkaa ja niitä voidaan käyttää ilmakehämallien ennusteiden tarkentamisessa.

Gammarid amphipods are a crucial link connecting primary producers with secondary consumers, but little is known about their nutritional ecology. Here we asked how starvation and subsequent feeding on different nutritional quality algae influences fatty acid retention, compound-specific isotopic carbon fractionation, and biosynthesis of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in the relict gammarid amphipod Pallaseopsis quadrispinosa. The fatty acid profiles of P. quadrispinosa closely matched with those of the dietary green algae after only seven days of refeeding, whereas fatty acid patterns of P. quadrispinosa were less consistent with those of the diatom diet. This was mainly due to P. quadrispinosa suffering energy limitation in the diatom treatment which initiated the metabolization of 16:1 omega 7 and partly 18:1 omega 9 for energy, but retained high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) similar to those found in wild-caught organisms. Moreover, alpha-linolenic acid (ALA) from green algae was mainly stored and not allocated to membranes at high levels nor biosynthesized to EPA. The arachidonic acid (ARA) content in membrane was much lower than EPA and P. quadrispinosa was able to biosynthesize long-chain omega-6 PUFA from linoleic acid (LA). Our experiment revealed that diet quality has a great impact on fatty acid biosynthesis, retention and turnover in this consumer.

Microalgal bioremediation of recirculating aquaculture system (RAS) wastewater represents an alternative for wastewater treatment with the potential to generate valuable biomass. This study evaluated the effects of removing biological contamination and suspended solids from Nordic area RAS wastewater through filtration with 0.45 μm filters on the performance and nutritional value of microalgae. All three tested green microalgae (Haematococcus pluvialis, Monoraphidium griffithii, and Selenastrum sp.) were able to grow in raw (unfiltered) and filtered RAS wastewater. Cultivation in raw RAS wastewater decreased the ω-3 and ω-6 fatty acid content of H. pluvialis as compared to filtered wastewater, while no differences in cell density, nutrient removal, or fatty acid and amino acid contribution were seen for any microalgae between the treatments. Filtration of wastewater significantly reduced the content of actinobacterial fatty acid biomarkers in microalgal cultures compared to raw wastewater. The difference in actinobacterial fatty acid content between raw and filtered wastewater was species-specific. Our results suggest that with careful selection of microalgal species, RAS wastewater can be used for the production of high-quality microalgal biomass for further applications, such as aquaculture feeds, with no need to remove indigenous biological contaminants and suspended solids. peerReviewed

There is a growing demand for marine omega-3 fatty acids (FAs) that is produced in high amounts by some microalgae. Here we determined the FA profiles of two cold water adapted diatoms,Chaetoceros wighamiiandThalassiosira baltica. The cultures were acclimated to different temperatures (3, 7, 11, 15, and 19 °C) and irradiance (20, 40, 130, and 450 μmol photons m−2s−1) and the FA profiles were determined in exponential and stationary growth phases, the latter induced by different nutrient limitation (N, P, and Si). The maximum growth rate was obtained by both species at 11 °C, ≥ 130 μmol photons m−2s−1and was 0.8 day−1and 0.6 day−1forC. wighamiiandT. baltica, respectively. Both species contained relatively high amounts of eicosapentaenoic acid (EPA).Thalassiosira balticaaccumulated maximally ~ 30 mg EPA g−1ash-free dry weight (AFDW) under Si-limitation. The content of docosahexaenoic acid (DHA) was lower, reaching up to 4 mg DHA g−1AFDW inT. baltica. The concentration of EPA correlated positively with the chlorophylla:carbon ratio, suggesting that it is bound to membranes in the photosynthetic apparatus and the EPA content inT. balticawas high enough to consider it as a potent candidate for cultivation under cold (< 15 °C) conditions. Covering a wide range of environmental conditions, the strongest differentiation in FA profiles was observed between the species with the growth phase/nutrient limitation pattern as the second most important driver of the FA composition.

Caraway seeds contain between 0.5–7% essential oil, rich in monoterpenes that have a characteristic aroma and chemical properties. Caraway oil has several bioactive compounds that are of industrial importance, particularly for pharmaceutical and health care products. Carvone and limonene are the main terpenes present in caraway oil, which along with some unique fatty acids (i.e. petroselinic acid) determine caraway (Carum carvi L.) oil quality. Both terpenes are important raw materials for industrial applications and their concentration influences the price of caraway seed and oil, hence there is need for identifying management practices that may increase the concentration of these and other bioactive compounds to improve caraway seed oil quality. A field experiment with five treatments: a control and a series of foliar-applied micronutrients (either Cu, Mg, Mn or Zn was done to identify their potential to enhance caraway oil quality. Solid-phase microextraction and gas chromatography with a flame ionization detector were used to characterize oil quality. Our results indicate that while the micronutrient treatments have a significant effect on essential oil composition, both in carvone and limonene, such an effect was not found on all fatty acids but only in two of them—palmitoleic and vaccenic acid—, which were highest after the Mn treatment. Overall, the carvone content of the seeds decreased the least between years following Mn treatment. Mn treatment also caused an increase in limonene in the second year in contrast to the trend for all other treatments. The Mn foliar spray needs to be studied further to elucidate whether it could have a consistent positive effect on caraway oil seed quality upon adjusting dosage and spraying time. peerReviewed

Food quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on the abundance of high-quality phytoplankton. We found that biomanipulation had a positive impact on the abundance of taxa synthesizing sterols, EPA, and DHA and, concurrently, on the biomass of the keystone species Daphnia. In contrast, hypolimnetic aeration did not result in such a beneficial outcome, manifested as a decrease in the abundance of Daphnia and frequent phytoplankton blooms dominated by cyanobacteria suggesting reduction in the nutritional quality of food for Daphnia. Our analysis shows that the determination of the nutritional value of algae and the contribution of essential fatty acids and sterols is an effective method to evaluate the success of various restoration measures.

Background & Aims\ud \ud The I148M variant in PNPLA3 is the major genetic risk factor for non‐alcoholic fatty liver disease (NAFLD). The liver is enriched with polyunsaturated triglycerides (PUFA‐TGs) in PNPLA3‐I148M carriers. Gene expression data indicate that PNPLA3 is liver‐specific in humans, but whether it functions in adipose tissue (AT) is unknown. We investigated whether PNPLA3‐I148M modifies AT metabolism in human NAFLD.\ud Methods\ud \ud Profiling of the AT lipidome and fasting serum non‐esterified fatty acid (NEFA) composition was conducted in 125 volunteers (PNPLA3 148MM/MI, n = 63; PNPLA3 148II, n = 62). AT fatty acid composition was determined in 50 volunteers homozygous for the variant (PNPLA3 148MM, n = 25) or lacking the variant (PNPLA3 148II, n = 25). Whole‐body insulin sensitivity of lipolysis was determined using [2H5]glycerol, and PNPLA3 mRNA and protein levels were measured in subcutaneous AT and liver biopsies in a subset of the volunteers.\ud Results\ud \ud PUFA‐TGs were significantly increased in AT in carriers versus non‐carriers of PNPLA3‐I148M. The variant did not alter the rate of lipolysis or the composition of fasting serum NEFAs. PNPLA3 mRNA was 33‐fold higher in the liver than in AT (P < .0001). In contrast, PNPLA3 protein levels per tissue protein were three‐fold higher in AT than the liver (P < .0001) and nine‐fold higher when related to whole‐body AT and liver tissue masses (P < .0001).\ud Conclusions\ud \ud Contrary to previous assumptions, PNPLA3 is highly abundant in AT. PNPLA3‐I148M locally remodels AT TGs to become polyunsaturated as it does in the liver, without affecting lipolysis or composition of serum NEFAs. Changes in AT metabolism do not contribute to NAFLD in PNPLA3‐I148M carriers.

Littoral benthic primary production is considered the most important energy source of consumers in subarctic lakes. We analyzed essential fatty acid (EFA) and amino acid (EAA) content of 23 littoral benthic macroinvertebrate taxa as well as cladocerans and copepods from pelagic and littoral habitats of 8–9 subarctic lakes to compare their nutritional quality. Pelagic crustacean zooplankton had significantly higher EFA and total FA content (on average 2.6‐fold and 1.6‐fold, respectively) than littoral macroinvertebrates in all our study lakes. Specifically, docosahexaenoic acid (DHA), one of the most important EFA for juvenile fish, was almost exclusively found in pelagic copepods. In littoral macroinvertebrates, only Lymnaea (Gastropoda), Eurycercus (Cladocera), and Gammarus (Amphipoda) contained a low amount of DHA, whereas most littoral invertebrate taxa contained moderate amounts of eicosapentaenoic acid (EPA). The difference in DHA content may explain why so many generalist fish shift their diet to pelagic zooplankton at their peak abundance in mid/late‐summer. Meanwhile, the differences in EAA content between pelagic zooplankton and littoral invertebrates were much lower than for EFA suggesting a wider availability of EAA in subarctic lakes, except for methionine. In the studied subarctic lakes, EFA and EAA variation in consumers was more related to taxon‐specific than lake‐specific characteristics. This indicates that climate‐induced changes in the abundance and community structure of zooplankton vs. littoral macroinvertebrates will be important parameters in determining the availability of EFA and EAA to juvenile fish, and potentially fish production. peerReviewed

Elevated concentrations of dissolved organic carbon (DOC) promote browning of lakes, which alters the physicochemical properties of water and ecosystem functioning. However, browning‐induced changes in basal production of polyunsaturated fatty acids from the n‐3 and n‐6 families (n‐3 and n‐6 PUFA) in lakes are not fully understood. The concentrations of PUFA, which are micronutrients required to maintain growth and reproduction of consumers, have been suggested to either rise or decline in seston as a response to lake browning. Elevated DOC concentrations may also promote bacterial biomass and production and thus potentially increase the concentration of bacterial fatty acids (BAFA) in seston. We analyzed phytoplankton, bacteria and heterotroph biomasses, the taxonomic composition of phytoplankton, and the concentrations and mass fractions of bioseston PUFA, BAFA, eicosapentaenoic, and docosahexaenoic acids in ten boreal lakes in eastern Finland, with DOC concentration ranging from 2.8 to 18.7 mg/L. Our results showed that the abundance of PUFA in seston depended on the responses of phytoplankton biomass and community composition to lake browning. Lake browning increased seston PUFA and BAFA concentrations (expressed as µg/L) but not the contents (expressed as µg/mg bioseston C). Although low DOC lakes had a favorable phytoplankton community (in terms of PUFA content), the phytoplankton biomass in these oligotrophic lakes was so low that the concentration of PUFA remained low compared to high DOC lakes. The increasing concentration of PUFA in bioseston along the DOC gradient was mainly due to the increasing biomass of nuisance alga Gonyostomum semen . However, Gonyostomum may be too large for small‐sized zooplankton to ingest, and thus, the trophic transfer of PUFA may be impaired. The trajectories for lake browning and the basal production of PUFA also may depend on the source of carbon and associated nutrient loading; DOC and nutrient loading from agricultural areas may promote cyanobacteria dominance and decrease PUFA availability in lakes, while DOC runoff from more acidic and nutrient‐poor peatlands may promote Gonyostomum dominance and increase seston PUFA concentration. peerReviewed

Phytoplankton synthesizes essential ω-3 and ω-6 polyunsaturated fatty acids (PUFA) for consumers in the aquatic food webs. Only certain phytoplankton taxa can synthesize eicosapentaenoic (EPA; 20:5ω3) and docosahexaenoic acid (DHA; 22:6ω3), whereas all phytoplankton taxa can synthesize shorter-chain ω-3 and ω-6 PUFA. Here, we experimentally studied how the proportion, concentration (per DW and cell-specific), and production (µg FA L-1 day-1) of ω-3 and ω-6 PUFA varied among six different phytoplankton main groups (16 freshwater strains) and between exponential and stationary growth phase. EPA and DHA concentrations, as dry weight, were similar among cryptophytes and diatoms. However, Cryptomonas erosa had two–27 times higher EPA and DHA content per cell than the other tested cryptophytes, diatoms, or golden algae. The growth was fastest with diatoms, green algae, and cyanobacteria, resulting in high production of medium chain ω-3 and ω-6 PUFA. Even though the dinoflagellate Peridinium cinctum grew slowly, the content of EPA and DHA per cell was high, resulting in a three- and 40-times higher production rate of EPA and DHA than in cryptophytes or diatoms. However, the production of EPA and DHA was 40 and three times higher in cryptophytes and diatoms than in golden algae (chrysophytes and synyrophytes), respectively. Our results show that phytoplankton taxon explains 56%–84% and growth phase explains ~1% of variation in the cell-specific concentration and production of ω-3 and ω-6 PUFA, supporting understanding that certain phytoplankton taxa play major roles in the synthesis of essential fatty acids. Based on the average proportion of PUFA of dry weight during growth, we extrapolated the seasonal availability of PUFA during phytoplankton succession in a clear water lake. This extrapolation demonstrated notable seasonal and interannual variation, the availability of EPA and DHA being prominent in early and late summer, when dinoflagellates or diatoms increased.

Objective: To investigate the cross-sectional associations of dietary carbohydrate and fatty acid intakes with cognition in mid-childhood. Design: Dietary carbohydrate and fatty acid intakes were assessed using 4-d food records, and cognition was evaluated using the Raven’s Coloured Progressive Matrices (RCPM) score. The cross-sectional associations of dietary carbohydrate and fatty acid intakes with cognition were investigated using linear regression analyses adjusted for age, sex, body fat percentage, household income, parental education and daily energy intake. Setting: The baseline examinations of the Physical Activity and Nutrition in Children study. Participants: A population-based sample of 487 children (250 boys, 237 girls) aged 6–8 years living in the city of Kuopio, Finland. Results: A higher dietary intake of fructose (standardised regression coefficient, β = 0·24, P < 0·001), total fibre (β = 0·16, P = 0·02) and soluble fibre (β = 0·15, P = 0·02) was associated with a higher RCPM score in boys. Other dietary carbohydrates and fatty acids, including total carbohydrates, glucose, sucrose, starch, insoluble fibre, total fat, SFAs, MUFAs, PUFAs, palmitic acid (C16), stearic acid (C18), linoleic acid (C18:2), α-linoleic acid (C18:3), arachidonic acid (C20:4), EPA (C20:5n-3) and DHA (C22:6n-6), were not associated with the RCPM score in boys. Dietary carbohydrates or fatty acids were not associated with the RCPM score in girls. Conclusions: Higher dietary fructose and fibre intakes were associated with better cognition in boys, but not in girls. Dietary fatty acids were not related to cognition in boys or in girls. peerReviewed

Feeds and feeding constitute the major part of costs in intensive aquaculture. Any action to reduce feeding costs without negatively affecting fish production parameters and flesh quality would improve profitability of farming. Therefore, we studied the effects of feeding frequency on production parameters, stomach capacity and nutritional value of muscle in juvenile rainbow trout (Oncorhynchus mykiss) in an experiment with two stages. First, during the nine-week “starvation period” we fed rainbow trout (initial weight c. 40 g) with four different feeding protocols in an attempt to adapt the fish to a progressive decrease in the number of feeding days. During the second stage, a four-week “re-feeding period”, all fish were fed in excess on weekdays. Fish growth, feed intake, stomach size, and biomolecule content of muscle were monitored as response variables. During the starvation period, feed intake and growth decreased along with the number of feeding days. Compensatory growth during the refeeding was either only modest or absent. The fish in the starved groups were unable to significantly increase their stomach capacities. Starvation and re-feeding had only a slight effect on muscle fatty acid and amino acid composition. The used feeding protocols did not affect important production parameters (e.g. feed conversion or size variation). Our results suggest that despite differences in fish growth starvation and re-feeding hardly affect the nutritional value of fish. It is possible that several decades in captivity have made rainbow trout incapable to adjust their stomach size in respect to feeding frequency. peerReviewed

Viljelemällä mikroleviä kalojen kiertovesiviljelyn jätevedessä siitä voidaan poistaa ravinteita ja tuottaa niistä biomassaa. Menetelmää voidaan käyttää korvaamaan perinteistä jäteveden käsittelyä ja kehittämään vesiviljelyn kannattavuutta. Tässä työssä verrattiin kolmen eri viherlevälajin (Haematococcus pluvialis, Monoraphidium griffithii and Selenastrum sp.) kasvua, ravinteiden poistoa, sekä rasvahappo- ja aminohappoprofiileja, kun leviä kasvatettiin suodatetussa tai suodattamattomassa kiertovedessä tai levien elatusaineessa. Monoraphidium ja Selenastrum -lajien kasvunopeudet olivat pienemmät kiertovedessä (0.64 vrk-1 ja 0.50 vrk-1) kuin levien elatusaineessa (0.72 ja 0.59 vrk-1), mutta Haematococcus-levän kasvunopeudessa ei ollut eroa kasvuliuosten välillä (0.47 ja 0.51 vrk-1). Levien rasvahappokoostumukset erosivat lähinnä oleeinihapon (18:1n-9) osuuksien suhteen, jotka olivat alemmat kiertovedessä kaikilla levälajeilla. Aminohappoprofiileissa ei ollut suuria eroja kasvuliuosten välillä. Kiertoveden sisältämien pieneliöiden vaikutusta leviin testattiin vertaamalla suodatettua ja suodattamatonta kiertovettä. Levien kasvunopeudet ja typen- ja fosforinpoisto eivät eronneet suodatetun ja suodattamattoman kiertoveden välillä, mutta rasvahappo- ja aminohappoprofiileissa oli jonkin verran eroja. Tuloksien perusteella levien kasvatusta kiertovedessä voidaan suositella kiertoveden puhdistusmenetelmäksi, jonka avulla voidaan samalla tuottaa arvokasta biomassaa. Microalgae cultivation in recirculating aquaculture system’s (RAS’s) wastewater (WW) is a promising alternative to conventional WW treatment. Conversion of WW nutrients into biomass could lead to new developments in aquaculture. In this master’s thesis, I compared the growth, nutrient removal, fatty acid (FA) and amino acid (AA) profiles of three green microalgae: Haematococcus pluvialis, Monoraphidium griffithii and Selenastrum sp. grown in RAS WW and reference growth medium. WW negatively affected the specific growth rate of Monoraphidium (0.64 d-1) and Selenastrum sp. (0.50 d-1) compared to reference medium (0.72, 0.59 d-1, respectively), while Haematococcus was not significantly affected (0.47 - 0.51 d-1). FA differences between WW and reference medium were mostly driven by the increase of oleic acid (18:1n-9) in reference medium (Haematococcus: 3.7 - 10.6, Monoraphidium: 4.1 - 11.5, Selenastrum: 6.3 - 17.0 mean% contribution). AA contribution profiles did not present considerable differences between treatments. The effect of microorganisms in RAS WW was tested by cultivating microalgae in filtered WW. Filtered and unfiltered WW achieved the same specific growth rate and removal of nitrogen (N% 15 – 38%) and phosphate (P% 48 – 99 %) while minor differences were observed in their FA and AA profiles. These findings support the use of microalgae as an alternative technique for treatment of RAS WW while producing valuable biomass.

Proxy-indicators in lake sediments provide the only approach by which the dynamics of in-lake methane cycling can be examined on multi-decadal to centennial time scales. This information is necessary to constrain how lacustrine methane production, oxidation and emissions are expected to respond to global change drivers. Several of the available proxies for reconstructing methane cycle changes of lakes rely on interpreting past changes in the abundance or relevance of methane oxidizing bacteria (MOB), either directly (e.g. via analysis of bacterial lipids) or indirectly (e.g. via reconstructions of the past relevance of MOB in invertebrate diet). However, only limited information is available about the extent to which, at the ecosystem scale, variations in abundance and availability of MOB reflect past changes in in-lake methane concentrations. We present a study examining the abundances of fatty acids (FAs), particularly of 13C-depleted FAs known to be produced by MOB, relative to methane concentrations in 29 small European lakes. 39 surface sediment samples were obtained from these lakes and FA abundances were compared with methane concentrations measured at the lake surface, 10 cm above the sediments and 10 cm within the sediments. Three of the FAs in the surface sediment samples, C16:1ω7c, C16:1ω5c/t, and C18:1ω7c were characterized by lower δ13C values than the remaining FAs. We show that abundances of these FAs, relative to other short-chain FAs produced in lake ecosystems, are related with sedimentary MOB concentrations assessed by quantitative polymerase chain reaction (qPCR). We observed positive relationships between methane concentrations and relative abundances of C16:1ω7c, C16:1ω5c/t, and C18:1ω7c and the sum of these FAs. For the full dataset these relationships were relatively weak (Spearman's rank correlation (rs) of 0.34–0.43) and not significant if corrected for multiple testing. However, noticeably stronger and statistically significant relationships were observed when sediments from near-shore and deep-water oxic environments (rs = 0.57 to 0.62) and those from anoxic deep-water environment (rs = 0.55 to 0.65) were examined separately. Our results confirm that robust relationships exist between in-lake CH4 concentrations and 13C-depleted groups of FAs in the examined sediments, agreeing with earlier suggestions that the availability of MOB-derived, 13C-depleted organic matter for aquatic invertebrates increases with increasing methane concentrations. However, we also show that these relationships are complex, with different relationships observed for oxic and anoxic sediments and highest values measured in sediments deposited in oxic environments overlain with relatively methane-rich water. Furthermore, although all three 13C-depleted FA groups identified in our survey are known to be produced by MOB, they also receive contributions by other organism groups, and this will have influenced their distribution in our dataset. peerReviewed

Coronary heart disease (CHD) is a clinical manifestation of atherosclerosis. It is a major cause of mortality and morbidity both in Finland and globally. Even after the best known treatments a significant residual risk of CHD remains. A low plasma HDL cholesterol level (HDL, high-density lipoprotein) is a common lipid abnormality in patients affected by premature CHD and also a component of the metabolic syndrome, a cluster of risk factors for atherosclerosis associated with central obesity. In this study, a phenotype of low HDL cholesterol level and premature CHD was investigated in two Northern Finnish family populations. The aim was to find new biological factors accounting for the elevated CHD risk in the phenotype. In the subjects of family population I, plasma levels of antibodies (IgG, IgM, IgA) against experimental epitopes (malondialdehyde-acetaldehyde-modified, copper-oxidized) of oxidized LDL (low-density lipoprotein) particles were measured. In the subjects of family population II, capacity of HDL fractions (total HDL, HDL2 and HDL3) to accept cholesterol from a THP-1 experimental foam cell model was assayed (cholesterol efflux). In addition, a phospholipid composition of their HDL fractions (HDL2 and HDL3) was measured using liquid chromatography-mass spectrometry. The antibody levels were not related to CHD or to HDL cholesterol level. Instead, the cholesterol efflux to HDL2 fraction was clearly impaired in CHD, which was associated with the low HDL cholesterol level of the patients. The impaired cholesterol efflux to HDL2 fraction was primarily in conjunction with the metabolic syndrome. The phospholipid composition of HDL fractions was different between the affected and the non-affected subjects. As an example, characteristic of the metabolic syndrome were elevated contents of palmitic, palmitoleic or oleic acids relative to linoleic acid in lysophosphatidylcholines and phosphatidylcholines. In conclusion, the HDL fraction is both functionally and compositionally modified in the phenotype of low HDL cholesterol level and premature CHD. Especially the cholesterol efflux capacity of the HDL2 fraction and thus its many functional properties may be impaired. There are many characteristic features in the phospholipid composition of the HDL in the phenotype which were detected in HDL2 and HDL3 fractions. Tiivistelmä Sepelvaltimotauti on ateroskleroosin kliininen ilmenemismuoto. Se on merkittävimpiä kuolleisuuden ja sairastavuuden aiheuttajia niin Suomessa kuin maailmalla. Parhaillakin tunnetuilla hoidoilla sepelvaltimotaudille jää huomattava jäännösriski. Plasman matala HDL-kolesterolitaso (HDL, high-density lipoprotein) on yleinen lipidipoikkeavuus varhaista sepelvaltimotautia sairastavilla ja myös eräs metabolisen oireyhtymän, eli keskivartalolihavuuteen liittyvän ateroskleroosin riskitekijäkasauman, komponentti. Tässä väitöskirjassa tutkittiin matalan HDL-kolesterolitason ja varhaisen sepelvaltimotaudin fenotyyppiä kahdessa pohjoissuomalaisessa sukuaineistossa. Tavoitteena oli löytää uusia biologisia tekijöitä fenotyypin kohonneen sepelvatimotautiriskin taustalta. Ensimmäisen aineiston henkilöiden plasmasta mitattiin vasta-ainetasoja (IgG, IgM, IgA) LDL-hiukkasten (LDL, low-density lipoprotein) kokeellisia hapettuneita epitooppeja (malonidialdehydi-asetaldehydi-modioitu ja kuparilla hapetettu LDL) vastaan. Toisessa aineistossa mitattiin henkilöiden HDL-fraktioiden (kokonais-HDL, HDL2 ja HDL3) kykyä saada aikaan kolesterolin ulosvirtausta kokeellisesta THP-1 vaahtosolumallista. Lisäksi heidän HDL-fraktioidensa (HDL2, HDL3) fosfolipidikoostumus mitattiin nestekromatografi-massaspektrometri-laitteistolla. Vasta-ainetasot eivät liittyneet sepelvaltimotautiin tai HDL-kolesterolitasoon. Sen sijaan kolesterolin ulosvirtaus HDL2-fraktioon oli selkeästi alentunut sepelvaltimotaudissa, mikä liittyi potilaiden pieneen HDL-kolesterolipitoisuuteen. Alentunut ulosvirtaus HDL2-fraktioon liittyikin ensisijaisesti metaboliseen oireyhtymään. HDL-fraktioiden fosfolipidikoostumus erosi terveiden ja sairaiden välillä. Esimerkiksi metabolisessa oireryhtymässä tunnusomaista oli lysofosfatidyylikoliinien ja fosfatidyylikoliinien sisältämän palmitiinihapon, palmitoleiinihapon tai oleiinihapon suurentunut määrä suhteessa niiden sisältämän linoleenihapon määrään. Loppupäätelmä on, että matalan HDL-kolesterolitason ja varhaisen sepelvaltimotaudin fenotyypin HDL-fraktio on sekä toiminnaltaan että koostumukseltaan muuntunut. Erityisesti HDL2-fraktion kyky saada aikaan kolesterolin ulosvirtausta ja näin ollen sen monet toiminnalliset ominaisuudet voivat olla alentuneet. Fenotyypin HDL:n fosfolipidikoostumuksessa on monia tunnusomaisia piirteitä, joita havaittiin sekä HDL2- että HDL3-fraktiossa.

There is limited information about the molecular triggers leading to the uncoating of enteroviruses under physiological conditions. Using real-time spectroscopy and sucrose gradients with radioactively labeled virus, we show at 37°C, the formation of albumin-triggered, metastable uncoating intermediate of echovirus 1 without receptor engagement. This conversion was blocked by saturating the albumin with fatty acids. High potassium but low sodium and calcium concentrations, mimicking the endosomal environment, also induced the formation of a metastable uncoating intermediate of echovirus 1. Together, these factors boosted the formation of the uncoating intermediate, and the infectivity of this intermediate was retained, as judged by end-point titration. Cryo-electron microscopy reconstruction of the virions treated with albumin and high potassium, low sodium, and low calcium concentrations resulted in a 3.6-Å resolution model revealing a fenestrated capsid showing 4% expansion and loss of the pocket factor, similarly to altered (A) particles described for other enteroviruses. The dimer interface between VP2 molecules was opened, the VP1 N termini disordered and most likely externalized. The RNA was clearly visible, anchored to the capsid. The results presented here suggest that extracellular albumin, partially saturated with fatty acids, likely leads to the formation of the infectious uncoating intermediate prior to the engagement with the cellular receptor. In addition, changes in mono- and divalent cations, likely occurring in endosomes, promote capsid opening and genome release. IMPORTANCE There is limited information about the uncoating of enteroviruses under physiological conditions. Here, we focused on physiologically relevant factors that likely contribute to opening of echovirus 1 and other B-group enteroviruses. By combining biochemical and structural data, we show that, before entering cells, extracellular albumin is capable of priming the virus into a metastable yet infectious intermediate state. The ionic changes that are suggested to occur in endosomes can further contribute to uncoating and promote genome release, once the viral particle is endocytosed. Importantly, we provide a detailed high-resolution structure of a virion after treatment with albumin and a preset ion composition, showing pocket factor release, capsid expansion, and fenestration and the clearly visible genome still anchored to the capsid. This study provides valuable information about the physiological factors that contribute to the opening of B group enteroviruses. peerReviewed

Ecology of the glacial relict macrocrustacean Gammaracanthus lacustris, a rare inhabitant of deep Fennoscandian lakes, is poorly understood. We studied the life cycle and trophic position of this cold‐stenothermic amphipod in Lake Paasivesi, eastern Finland. The study is based on intensive sampling and analyses of fatty acid composition as well as stable carbon (δ13C) and nitrogen (δ15N) isotope ratios. Both day and night, the G. lacustris population occurred at depths below 25 m at temperatures 40 mm and live up to 4 years. The oldest and the largest individuals and females seemed to favour the deepest zones. In October, almost 100% of females with length at least 25 mm (i.e. females presumably at least 1‐year‐old) had an embryo sack with 20–200 eggs or embryos—the larger the female, the more young it had. The developing eggs of G. lacustris had a very high fatty acid content, indicating that the females invest heavily on provisioning their young. Furthermore, the fatty acid composition differed among life stages, and in particular the eggs had a higher proportion of eicosapentaenoic acid than juveniles or adults. The stable δ13C and δ15N isotope ratios and fatty acid biomarkers of the food web, together with visual observations, indicate that G. lacustris is a carnivore that feeds mainly on zooplankton and other relict macrocrustaceans. Due to its high content of essential polyunsaturated fatty acids, G. lacustris is a valuable prey for fish and other predators in the food web. However, as a glacial relict with strict habitat requirements the species is vulnerable to global warming and local environmental changes. These facts should be considered in the management of lakes and their catchments. peerReviewed

Eutrophication (as an increase in total phosphorus [TP]) increases harmful algal blooms and reduces the proportion of high-quality phytoplankton in seston and the content of ω-3 long-chain polyunsaturated fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) in fish. However, it is not well-known how eutrophication affects the overall nutritional value of phytoplankton. Therefore, we studied the impact of eutrophication on the production (as concentration; μg L−1) and content (μg mg C−1) of amino acids, EPA, DHA, and sterols, i.e., the nutritional value of phytoplankton in 107 boreal lakes. The lakes were categorized in seven TP concentration categories ranging from ultra-oligotrophic (50 μg L−1). Phytoplankton total biomass increased with TP as expected, but in contrast to previous studies, the contribution of high-quality phytoplankton did not decrease with TP. However, the high variation reflected instability in the phytoplankton community structure in eutrophic lakes. We found that the concentration of amino acids increased in the epilimnion whereas the concentration of sterols decreased with increasing TP. In terms of phytoplankton nutritional value, amino acids, EPA, DHA, and sterols showed a significant quadratic relationship with the lake trophic status. More specifically, the amino acid contents were the same in the oligo- and mesotrophic lakes, but substantially lower in the eutrophic lakes (TP > 35 μg L−1/1.13 μmol L−1). The highest EPA and DHA content in phytoplankton was found in the mesotrophic lakes, whereas the sterol content was highest in the oligotrophic lakes. Based on these results, the nutritional value of phytoplankton reduces with eutrophication, although the contribution of high-quality algae does not decrease. Therefore, the results emphasize that eutrophication, as excess TP, reduces the nutritional value of phytoplankton, which may have a significant impact on the nutritional value of zooplankton, fish, and other aquatic animals at higher food web levels. peerReviewed

Climate change and land-use practices can enhance lake eutrophication and browning, which influence phytoplankton composition by decreasing the availability of food high in nutritional quality (algae) and increasing the abundance of low-quality food (terrestrial detritus, bacteria) for herbivorous zooplankton. Nutritionally valuable algae for zooplankton are rich in essential biomolecules such as amino acids, polyunsaturated fatty acids (PUFAs), sterols, and phosphorus. We performed laboratory experiments and showed a stronger positive relationship between zooplankton (Daphnia) cumulative offspring number and availability of high-quality algae (Cryptophytes: Rhodomonas/Cryptomonas; and Chrysophytes: Mallomonas) than with intermediate-quality (Chlorophytes: Acutodesmus) or poor-quality (Dinoflagellates: Peridinium) algae. The higher cumulative offspring number of Daphnia was a result of higher amounts of total ω-3 and ω-6 PUFA, proteins, sterols, and amino acids in the algal diets. The experiments also showed that even a small addition of high-quality algae (Rhodomonas) to intermediate-quality (Acutodesmus) or low-quality (bacteria, heterotrophic nanoflagellates, or terrestrial organic matter) diets can enhance the Daphnia cumulative offspring production. Our carbon mass balance calculation for a eutrophic clearwater lake and an oligotrophic polyhumic lake showed that the abundance of high-quality phytoplankton (cryptophytes, chrysophytes, diatoms) among total particulate organic carbon was minor (8.7% [SD 2.4%] and 6.5% [7.0%]). We modeled Daphnia diets (i.e., resource assimilation) using a fatty acid mixing model. Our analyses showed that Daphnia were able to locate high-quality algae (cryptophytes, chrysophytes, and diatoms) more effectively during cyanobacteria blooms in a eutrophic lake (55% [SD 12%]) than in a polyhumic lake (25% [10%]). Nevertheless, our results show that intense eutrophication and browning diminish assimilation of high quality algae, limiting Daphnia biomass production. peerReviewed

Recent studies have clearly shown the importance of omega-3 (&omega, 3) and omega-6 (&omega, 6) polyunsaturated fatty acids (PUFAs) for human and animal health. The long-chain eicosapentaenoic acid (EPA, 20:5&omega, 3) and docosahexaenoic acid (DHA, 22:6&omega, 3) are especially recognized for their nutritional value, and ability to alleviate many diseases in humans. So far, fish oil has been the main human source of EPA and DHA, but alternative sources are needed to satisfy the growing need for them. Therefore, we compared a fatty acid profile and content of 10 diatoms and seven dinoflagellates originating from marine, brackish and freshwater habitats. These two phytoplankton groups were chosen since they are excellent producers of EPA and DHA in aquatic food webs. Multivariate analysis revealed that, whereas the phytoplankton group (46%) explained most of the differences in the fatty acid profiles, habitat (31%) together with phytoplankton group (24%) explained differences in the fatty acid contents. In both diatoms and dinoflagellates, the total fatty acid concentrations and the &omega, 3 and &omega, 6 PUFAs were markedly higher in freshwater than in brackish or marine strains. Our results show that, even though the fatty acid profiles are genetically ordered, the fatty acid contents may vary greatly by habitat and affect the &omega, 6 availability in food webs.

The effects of multiple stressors are difficult to separate in field studies, and their interactions may be hard to predict if studied in isolation. We studied the effects of decreasing food quality (increase in cyanobacteria from 5 to 95% simulating eutrophication), temperature increase (by 3 °C), and microplastic exposure (1% of the diet) on survival, size, reproduction, and fatty acid composition of the model freshwater cladoceran Daphnia magna. We found that food quality was the major driver of Daphnia responses. When the amount of cyanobacteria increased from 5 to 95% of the diet, there was a drastic decrease in Daphnia survival (from 81 ± 15% to 24 ± 21%), juvenile size (from 1.8 ± 0.2 mm to 1.0 ± 0.1 mm), adult size (from 2.7 ± 0.1 mm to 1.1 ± 0.1 mm), and reproduction (from 13 ± 5 neonates per surviving adult to 0), but the decrease was not always linear. This was most likely due to lower availability of lipids, eicosapentaenoic acid (EPA), and sterols from the diet. Microplastic exposure did not affect Daphnia survival, size, or reproduction. Food quality had an interactive effect with temperature on fatty acid content of Daphnia. Total fatty acid content of Daphnia was almost 2-fold higher at 20 °C than at 23 °C when fed 50% cyanobacteria. This may have implications for higher trophic level consumers, such as fish, that depend on zooplankton for energy and essential lipids. Our findings suggest that as proportions of cyanobacteria increase, in tandem with water temperatures due to climate change, fish may encounter fewer and smaller Daphnia with lower lipid and EPA content. peerReviewed

During alkaline pulping significant amounts of lignin, carbohydrates (mostly hemicelluloses), and extractives (tall oil soap and turpentine) are removed from wood feedstock. In this study, the catalytic esterification of fatty acids in tall oil with methanol to produce fatty acid methyl esters under microwave irradiation was performed at 100 °C for 10–60 min. A novel heterogeneous acid catalyst tested for this purpose was synthesized from the hardwood alkali lignin that was precipitated by acidification from the black liquor from soda-AQ pulping. The comparative reaction data were obtained by using other solid catalysts, Amberlyst 15, and p-toluenesulfonic acid. The results showed the highest esterification yields of 93, 88, and 80% with the p-toluenesulfonic acid, lignin-based, and Amberlyst 15 catalysts, respectively, at 100 °C with a reaction time of 60 min, and the corresponding yield without catalyst was 20%. It was also observed that the lignin-based catalyst could be easily recovered and reused without any notable deactivation. peerReviewed

Source at https://doi.org/10.1002/ece3.3832. The first few months of life is the most vulnerable period for fish and their optimal hatching time with zooplankton prey is favored by natural selection. Traditionally, however, prey abundance (i.e., zooplankton density) has been considered important, whereas prey nutritional composition has been largely neglected in natural settings. High‐quality zooplankton, rich in both essential amino acids (EAAs) and fatty acids (FAs), are required as starting prey to initiate development and fast juvenile growth. Prey quality is dependent on environmental conditions, and, for example, eutrophication and browning are two major factors defining primary producer community structures that will directly determine the nutritional quality of the basal food sources (algae, bacteria, terrestrial matter) for zooplankton. We experimentally tested how eutrophication and browning affect the growth and survival of juvenile rainbow trout (Oncorhynchus mykiss) by changing the quality of basal resources. We fed the fish on herbivorous zooplankton (Daphnia) grown with foods of different nutritional quality (algae, bacteria, terrestrial matter), and used GC‐MS, stable isotope labeling as well as bulk and compound‐specific stable isotope analyses for detecting the effects of different diets on the nutritional status of fish. The content of EAAs and omega‐3 (ω‐3) polyunsaturated FAs (PUFAs) in basal foods and zooplankton decreased in both eutrophication and browning treatments. The decrease in ω‐3 PUFA and especially docosahexaenoic acid (DHA) was reflected to fish juveniles, but they were able to compensate for low availability of EAAs in their food. Therefore, the reduced growth and survival of the juvenile fish was linked to the low availability of DHA. Fish showed very low ability to convert alpha‐linolenic acid (ALA) to DHA. We conclude that eutrophication and browning decrease the availability of the originally phytoplankton‐derived DHA for zooplankton and juvenile fish, suggesting bottom‐up regulation of food web quality.

Intrinsic factors related to muscle metabolism may explain the differences in mechanical efficiency (ME) during exercise. Therefore, this study aimed to investigate the relationship between muscle metabolism and ME. Totally 17 healthy recreationally active male participants were recruited and divided into efficient (EF; n = 8) and inefficient (IE; n = 9) groups, which were matched for age (mean ± SD 24 ± 2 vs. 23 ± 2 years), BMI (23 ± 1 vs. 23 ± 2 kg m−2), physical activity levels (3.4 ± 1.0 vs. 4.1 ± 1.0 sessions/week), and V˙O2peak (53 ± 3 vs. 52 ± 3 mL kg−1 min−1), respectively, but differed for ME at 45% of V˙O2peak intensity during submaximal bicycle ergometer test (EF 20.5 ± 3.5 vs. IE 15.4 ± 0.8%, P < 0.001). Using positron emission tomography, muscle blood flow (BF) and uptakes of oxygen (mV˙O2), fatty acids (FAU) and glucose (GU) were measured during dynamic submaximal knee-extension exercise. Workload-normalized BF (EF 35 ± 14 vs. IE 34 ± 11 mL 100 g−1 min−1, P = 0.896), mV˙O2 (EF 4.1 ± 1.2 vs. IE 3.9 ± 1.2 mL 100 g−1 min−1, P = 0.808), and GU (EF 3.1 ± 1.8 vs. IE 2.6 ± 2.3 μmol 100 g−1 min−1, P = 0.641) as well as the delivery of oxygen, glucose, and FAU, as well as respiratory quotient were not different between the groups. However, FAU was significantly higher in EF than IE (3.1 ± 1.7 vs. 1.7 ± 0.6 μmol 100 g−1 min−1, P = 0.047) and it also correlated with ME (r = 0.56, P = 0.024) in the entire study group. EF group also demonstrated higher use of plasma FAU than IE, but no differences in use of plasma glucose and intramuscular energy sources were observed between the groups. These findings suggest that the effective use of plasma FAU is an important determinant of ME during exercise. peerReviewed

Microalgae have the ability to synthetize many compounds, some of which have been recognized as a source of functional ingredients for nutraceuticals with positive health effects. One well-known example is the long-chain polyunsaturated fatty acids (PUFAs), which are essential for human nutrition. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the two most important long-chain omega-3 (-3) PUFAs involved in human physiology, and both industries are almost exclusively based on microalgae. In addition, algae produce phytosterols that reduce serum cholesterol. Here we determined the growth rates, biomass yields, PUFA and sterol content, and daily gain of eight strains of marine cryptophytes. The maximal growth rates of the cryptophytes varied between 0.34-0.70 divisions day(-1), which is relatively good in relation to previously screened algal taxa. The studied cryptophytes were extremely rich in -3 PUFAs, especially in EPA and DHA (range 5.8-12.5 and 0.8-6.1 mu g mg dry weight(-1), respectively), but their sterol concentrations were low. Among the studied strains, Storeatula major was superior in PUFA production, and it also produces all PUFAs, i.e., -linolenic acid (ALA), stearidonic acid (SDA), EPA, and DHA, which is rare in phytoplankton in general. We conclude that marine cryptophytes are a good alternative for the ecologically sustainable and profitable production of health-promoting lipids.

The growth and reproduction of animals is affected by their access to resources. In aquatic ecosystems, the availability of essential biomolecules for filter-feeding zooplankton depends greatly on phytoplankton. Here, we analyzed the biochemical composition, i.e., the fatty acid, sterol and amino acid profiles and concentrations as well as protein, carbon, nitrogen, and phosphorus content of 17 phytoplankton monocultures representing the seven most abundant phytoplankton classes in boreal and sub-arctic lakes. To examine how the differences in the biochemical composition between phytoplankton classes affect their nutritional quality for consumers, we assessed the performance of Daphnia, on these diets. Furthermore, we defined the most important biomolecules regulating the somatic growth and reproduction of Daphnia, expecting that higher concentrations of certain biomolecules are needed for reproduction than for growth. Finally, we combined these results with phytoplankton field data from over 900 boreal and sub-arctic lakes in order to estimate whether the somatic growth of Daphnia is sterol-limited when the natural phytoplankton communities are cyanobacteria-dominated. Our analysis shows that Daphnia grows best with phytoplankton rich in sterols, ω-3 fatty acids, protein, and amino acids. Their reproduction follows food sterol and ω-3 concentration as well as C:P-ratio being two times higher in Daphnia feeding on cryptophytes than any other diet. Interestingly, we found that a high dietary ω-6 fatty acid concentration decreases both somatic growth and reproduction of Daphnia. When combined with phytoplankton community composition field data, our results indicate that zooplankton is constantly limited by sterols in lakes dominated by cyanobacteria (≥40% of total phytoplankton biomass), and that the absence of cryptophytes can severely hinder zooplankton production in nature. peerReviewed

Direct consumption of allochthonous resources generally yields poor growth and reproduction in zooplankton, but it is still unclear how trophic upgrading of terrestrial dissolved organic matter (tDOM) via the microbial food web may support zooplankton. We compared survival, somatic growth and reproduction of Daphnia magna fed with the heterotrophic flagellate Paraphysomonas vestita and three algal diets. Paraphysomonas was fed lake bacteria that used tDOM as a substrate to simulate an allochthonous diet that zooplankton encounter in lakes. The highest survival, growth and reproduction was achieved with a diet of Cryptomonas, while Daphnia performance was the worst when fed Microcystis. Paraphysomonas and Scenedesmus diets lead to intermediate growth and reproduction. Cryptomonas contained high amounts of essential polyunsaturated fatty acids (PUFA) and phytosterols that supported high somatic growth and reproduction, whereas poor performance of Daphnia on the cyanobacterial diet was most likely due to lack of sterols. Paraphysomonas contained some phytosterols, but not in sufficient amounts, and also essential PUFA (eicosapentaenoic and arachidonic acid) that enhance zooplankton growth and reproduction. Our results indicate that the tDOM-based microbial food web supports Daphnia performance even as a sole food source, and may be important in providing zooplankton with essential biochemical components when phytoplankton quantity or quality is low., final draft, peerReviewed

Innovative biorefinery concepts were developed for the separation and utilization of organic materials, especially aliphatic carboxylic acids, lignin, and extractives, which are formed as by-products during wood-based alkaline delignification processes. The partial recovery of sodium as NaOH and aliphatic carboxylic acids from hardwood soda-AQ black liquor was studied via electrodialysis. The lignin was partly (about 59 % of the initial lignin) precipitated from black liquor by carbonation (pH to about 8.5) followed by electrodialysis or H2SO4 (pH to about 2), with subsequent precipitation of more lignin and the liberation of aliphatic acids. The Na2SO4 formed was successfully separated from the acidified liquor by precipitation with methanol and treated by electrodialysis to recover NaOH and H2SO4 for recycling. The electrodialysis of Na2SO4 was effective and almost 90 % of the sodium was recovered. Volatile formic and acetic acids were recovered from acidified black liquor (pH about 2) by simple distillation and the recovery of the significant low- molar-mass hydroxy carboxylic acids (glycolic, lactic, and 2-hydroxybutanoic acids) by means of their methyl esters for chemical utilization. The residual high-molar-mass acids (3,4-dideoxy-pentonic, 3-deoxy-pentonic, xyloisosaccharinic, and glucoisosaccharinic acids) present in the form of their lactones were then utilized in the production of surfactants with tall oil fatty acids. The esterification of the model compound α-glucoisosaccharino-1,4-lactone with lauric, oleic, and tall oil fatty acids was studied separately in a microwave reactor in the presence of p-toluenesulfonic acid as a catalyst, and the total yields varied in the range of 40-62 %. The precipitated lignin obtained by carbonation and acidification with H2SO4 was separated and characterized with Fourier transform infrared, ultraviolet, energy dispersive X-ray fluorescence, and nuclear magnetic resonance spectroscopy. In addition, the molar weight distributions of these lignin fractions were determined using gel permeation chromatography. The lignin obtained by acidification was employed in synthesis of an acid catalyst. This lignin-based acid catalyst was made by phenol formaldehyde condensation, followed by a sulfonation reaction. The esterification of tall oil fatty acids with methanol was studied in a microwave reactor in the presence of various catalysts, such as lignin-based acid catalyst, p-toluenesulfonic acid, and Amberlyst 15. Compared to other catalysts, the lignin-based acid catalyst showed a good activity, and it also could be easily recycled.

Accumulating evidence indicates that gut microbiota plays a significant role in obesity, insulin resistance and associated liver disorders. Family Enterobacteriaceae and especially Enterobacter cloacae strain B29 have been previously linked to obesity and hepatic damage. The underlying mechanisms, however, remain unclear. Therefore, we comprehensively examined the effects of E. cloacae subsp. cloacae (ATCC® 13047™) administration on host metabolism of mice fed with high-fat diet (HFD). C57BL/6N mice were randomly divided into HFD control, chow control, and E. cloacae treatment groups. The E. cloacae treatment group received live bacterial cells in PBS intragastrically twice a week, every other week for 13 weeks. Both control groups received PBS intragastrically. After the 13- week treatment period, the mice were sacrificed for gene and protein expression and functional analyses. Our results show that E. cloacae administration increased subcutaneous fat mass and the relative proportion of hypertrophic adipocytes. Both subcutaneous and visceral fat had signs of decreased insulin signaling and elevated lipolysis that was reflected in higher serum glycerol levels. In addition, E. cloacae -treated mice had significantly higher hepatic AST and AST/ALT ratio, and their liver histology indicated fibrosis, demonstrating that E. cloacae subsp. cloacae administration promotes hepatic damage in HFD fed mice. peerReviewed

Tämän tutkimuksen tarkoitus oli selvittää, onko silakansyönnistä enemmän terveyshyötyä kuin -haittaa Suomessa ja millainen tilanne on eri ikäryhmissä. Aiemmat hyöty-riskiarviot ovat osoittaneet, että kalansyönti on yleensä terveellisempää kuin sen syömättä jättäminen. Tämä johtuu erityisesti kalan terveellisistä omega-3-rasvahapoista. Kuitenkin iso osa hyödyistä tulee aikuisille, joilla on suurentunut sydäntautiriski, ja osa mahdollisista haitoista tulee lapsille hammasvaurioiden ja muiden kehityshäiriöiden riskinä. Eviran toimeksiantona, yhteistyössä THL:n kanssa on vuoden 2014 aikana tehty hyöty-haitta-analyysi, jossa on tarkasteltu nimenomaan eri ikäryhmiä erikseen nykyisen kalankäytön mukaan. Tulokset perustuvat Taloustutkimuksen tekemän kyselyn aineistoon vuodelta 2013, jonka pohjalta on tehty varsinainen terveysvaikutusten tarkastelu. Tulokset ilmaistiin käyttäen haittapainotettuja elinvuosia (Disability Adjusted Life Year DALY) eli yksi DALY vastaa yhtä menetettyä tervettä elinvuotta. Hyödyllisistä ravintoaineista raportissa tarkasteltiin omega-3-rasvahappoja, eikosapentaeenihappoa (EPA) ja dokosaheksaeenihappoa (DHA) sekä D-vitamiinia. Silakassa esiintyvistä terveydelle haitallisista ympäristömyrkyistä tarkasteltiin dioksiineihin luettavia yhdisteitä, joihin kuuluvat polyklooratut dibentso-p-dioksiinit ja polyklooratut furaanit sekä dioksiininkaltaiset polyklooratut bifenyylit (PCB:t). Tulosten mukaan silakansyönti aiheuttaa Suomessa noin 11 (95 % luottamusväli LV 0 – 54) DALY kehityshäiriöistä (hammasvaurio) johtuvaa haittapainotettua elinvuotta (DALY), jotka kaikki kohdistuvat lapsiin äidin välityksellä raskausajan ja imetyksen kautta. Lisäksi silakansyönti aiheuttaa noin 12 (95 % LV 1.7 – 56) DALY dioksiinien aiheuttaman syöpäriskin kautta koko väestössä. Yli 50-vuotiailla naisilla ja varsinkin miehillä silakansyönnin terveyshyödyt ovat selkeästi suuremmat kuin terveyshaitat. Suurimmat terveyshyödyt saadaan sydäntautia ja sydänkuolleisuutta vähentävästä vaikutuksesta, noin -688 (95 % LV -2126 – -41) DALY/vuosi. Tulosten mukaan silakan syönti on vähentynyt väestössä niin paljon, että nykyiset suomalaiset kalan yleiset syöntisuositukset ovat riittävät suojaamaan väestöä dioksiinien ja dioksiinien kaltaisten yhdisteiden aiheuttamilta terveyshaitoilta. Hyöty-haitta-analyysissä tulisi kuitenkin tulevaisuudessa arvioida myös muiden rasvaisten kalojen keräämien ympäristömyrkkyjen kumulatiivisia terveysvaikutuksia ja yleisten syöntisuositusten riittävyyttä. Syftet med denna undersökning var att utreda om konsumtion av strömming från Östersjön ger mer hälsofördelar än hälsoskador i Finland och hurdant läget i olika ålderskategorier är. Tidigare nytta/riskvärderingar har visat att det i allmänhet är hälsosammare att äta fisk än att låta bli att göra det. Det beror särskilt på de hälsosamma omega-3-fettsyrorna i fisken. En stor del av fördelarna tillkommer ändå vuxna personer med förhöjd risk för hjärtsjukdomar och en stor del av skadorna tillkommer barn i form av risk för skador på tänderna och andra utvecklingsstörningar. På uppdrag från Evira och i samarbete med THL har under året 2014 gjorts en nytta/riskanalys, där man uttryckligen granskat olika ålderskategorier skilt för sig i ljuset av den nuvarande konsumtionen av strömming. Resultaten bygger på ett enkätmaterial som Taloustutkimus inhämtat år 2013. Utgående från detta material har sedan den egentliga granskningen av hälsoeffekterna gjorts. Resultaten angavs i form av funktionsjusterade levnadsår (Disability Adjusted Life Year DALY). För de nyttiga näringsämnenas del granskades i rapporten omega-3-fettsyrorna eikosapentaensyra (EPA) och dokosahexaensyra (DHA) och vitamin D. Av de hälsovådliga miljögifterna som förekommer i strömming granskades dioxiner, polyklorerade dibenzo-p-dioxinerna och plyklorerade dibenzofuranerna jämte dioxinliknande polyklorerade bifenylerna (PCB). Resultaten visar att konsumtion av strömming i Finland orsakar cirka 11 (95 % förtroende intervall , FI 0-54) funktionsjusterade levnadsår (DALY) som beror på utvecklingsstörningar (tandskada) och som alla via modern drabbar barn under graviditeten och amningen. Konsumtion av strömming medför också cirka 12 (95 %, FI 1,7-56) DALY via den cancerrisk som dioxinerna orsakar i hela befolkningen. Hos över 50 åriga kvinnor och framförallt män är fördelarna av att äta strömming klart större än hälsoskadorna. De största hälsofördelarna kommer av att risken för hjärtsjukdomar och dödligheten i hjärtsjukdomar minskar, cirka -688 (95 %, FI -2126 -41) DALY/år. Enligt resultaten konsumtion av strömming I Finland har sjunkit till en så låg nivå , att de nuvarande allmänna rekommenderade intagen av fisk konsumtion är tillräckliga för att skydda befolkningen mot hälsoskador av dioxiner eller dioxinlika föreningar. I risk-nytta-analys i framtiden bör ändå utvärderas totala hälsoeffekter av olika miljögifter i andra feta fiskarter ock kolla lämpligheten av rekommendationer av fisk konsumtion. The objective of this study was to determine whether the benefits of eating Baltic Sea herring exceed the risks in Finland, and what the situation is in different age groups. Previous risk-benefit analyses have shown that eating fish is in general healthier than not eating fish. This is particularly due to the healthy omega 3 fatty acids of fish. However, the benefits are largely enjoyed by adults with an elevated risk of heart disease, while children suffer the majority of the risks in the form of dental problems and other developmental disorders. In the riskbenefit analysis carried out to the order of Evira in collaboration with THL during 2014, different age groups were specifically considered separately in the light of current fish consumption. The results are based on the survey of the consumption of Baltic herring conducted by Taloustutkimus in 2013, which was used as the basis for the actual analysis of health effects. The results were expressed as Disability Adjusted Life Years (DALY). Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as well as vitamin D were analysed in the report as beneficial nutrients. As far as environmental toxins harmful to health are concerned, Baltic herring were analysed for compounds classified as dioxins, which include polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, as well dioxin-like biphenyls (PCB). According to the results, in Finland eating herring causes ca. 11 (95% confidence interval, CI 0-54) Disability Adjusted Life Years (DALYs) resulting from developmental disorders (dental damage); these affect children via the mother during pregnancy and breastfeeding. In addition, eating herring causes a ca. 12 (95%, CI 1,7-56) DALY cancer risk due to dioxins in the entire population. The health benefits of eating herring clearly exceed risks to health for women and particularly men after the age of 50 years. The greatest health benefits result from the reduction in heart disease and heart-related fatality, ca. –688 (95%, CI -2126 -41) DALY/year. The results show that the consumption of Baltic herring has decreased in Finland to a low level and that the current common dietary advices on fish consumption are adequate to protect the population against the adverse health effects of dioxins and dioxin-like compounds. However, in risk benefit analysis in future it is important to estimate the total health effects of different environmental pollutants and of other fatty fish, and the sufficiency of dietary advices on fish consumption.