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Microplastic are an emerging environmental contaminant that have raised concerns regarding their potential impact on human health. Ingestion is considered the primary route of human microplastic exposure, with food and beverage contamination being major contributors. This study aimed to evaluate the applicability of an existing microplastic extraction protocol, design for rat feces, on human fecal samples and to assess the occurrence, polymer composition and potential dietary sources of microplastic in individuals from Norway. Participants were selected based on their seafood consumption status, categorized in seafood consumers ( n  = 9) and non-seafood consumers ( n  = 9). The extraction protocol involved the matrix digestion in 15% H 2 O 2 : 5% HNO 3 and 10% KOH. Microplastic particles were then identified by µ-FTIR. Microplastic were detected in 17 out of 18 fecal samples with a total of 132 particles and sizes ranging from 12.5 to 4065 μm. Polypropylene was the most prevalent polymer (72%), followed by polyethylene (44%) and polystyrene (16%). There was no significant association between microplastic abundance and seafood consumption, or with other food groups, such as chocolate and chips. These findings suggest that dietary habits alone may not be the primary determinant of microplastic exposure. Moreover, this study highlights the necessity for harmonized microplastic extraction protocols and broader investigations into regional and individual variations in microplastic exposure. Highlights MP detected in 94% of fecal samples, with polypropylene being the most prevalent polymer. Smaller microplastic (10–50 μm) are the most abundant size class. No significant association found between MP abundance and seafood consumption or processed food intake.

The pollution of the environment with plastics is of growing concern worldwide, including the Arctic region. While larger plastic pieces are a visible pollution issue, smaller microplastics are not visible with the naked eye. These particles are available for interaction by Arctic biota and have become a concern for animal and human health. The determination of microplastic properties includes several methodological steps, i.e., sampling, extraction, quantification, and chemical identification. This review discusses suitable analytical tools for the identification, quantification, and characterization of microplastics in the context of monitoring in the Arctic. It further addresses quality assurance and quality control (QA/QC), which is particularly important for the determination of microplastic in the Arctic, as both contamination and analyte losses can occur. It presents specific QA/QC measures for sampling procedures and for the handling of samples in the laboratory, either on land or on ship, and considering the small size of microplastics as well as the high risk of contamination. The review depicts which data should be mandatory to report, thereby supporting a framework for harmonized data reporting.

Iodine is a trace element required for the production of thyroid hormones, essential for metabolism, growth and brain development, particularly in the first trimester of pregnancy. Milk and lean fish are the main dietary sources of iodine in the Norwegian diet. Thus, the aim of the present study was to provide updated analysed values of iodine concentration in six fish species, 27 selected Norwegian iodine-rich dairy foods and Norwegian hen's eggs. The iodine concentrations in the wild fish species varied between 18 μg/100 g (Atlantic halibut) and 1,210 μg/100 g (pollack). The iodine concentration of cow milk varied between 12 and 19 μg/100 g and the iodine concentration of the eggs varied between 23 and 43 μg/100 g. The results in this study deviate somewhat from the current iodine concentrations in the Norwegian Food Composition Table. This deviation may have a large impact on the assessment of the iodine intake. Hence, updated knowledge about the variation in iodine level of fish, milk, dairy products and hen's egg are of great importance when estimating the iodine intake in the population. These data will contribute substantially to future estimations of dietary iodine intake and will be made available for the public Norwegian Food Composition Table.

In this review, we investigated published data on the occurrence of microplastic in Arctic fish, and the suitability of the data and species for risk assessment and monitoring. As of 11.11.2021, we found nine studies in the peer-reviewed literature, one thesis and one report, confirming the occurrence of microplastic in fishes from multiple Arctic regions. The studies varied in methodology, detection and quantification limitations, reported categories of size, shape, and chemical identity. All these factors influence the numbers of microplastic reported, thus limiting comparability and hindering integrative analysis. The physiological impacts of the reported microplastic contamination cannot be determined, as all studies targeted stomach/intestine contents and did not use methods with limits of detection low enough to determine particle translocation from the intestine to other organs, tissues or body fluids within the fish. Furthermore, there is a fundamental lack of understanding the transfer and the effects of plastic additives to Arctic fishes. In addition to discussing methodological challenges and knowledge gaps, we consider ecosystem needs, commercial interests, Indigenous people’s subsistence, food safety and food sovereignty concerns, and developed a framework to harmonize and facilitate pan-Arctic microplastic monitoring.

The Arctic Monitoring and Assessment Programme has published a plan and guidelines for the monitoring of litter and microplastics (MP) in the Arctic. Here, we look beyond suggestions for immediate monitoring and discuss challenges, opportunities, and future strategies in the long-term monitoring of litter and MP in the Arctic. Challenges are related to environmental conditions, lack of harmonization and standardization of measurements, and long-term coordinated and harmonized data storage. Furthermore, major knowledge gaps exist with regard to benchmark levels, transport, sources, and effects, which should be considered in future monitoring strategies. Their development could build on the existing infrastructure and networks established in other monitoring initiatives in the Arctic, while taking into account specific requirements for litter and MP monitoring. Knowledge existing in northern and Indigenous communities, as well as their research priorities, should be integrated into collaborative approaches. The monitoring plan for litter and MP in the Arctic allows for an ecosystem-based approach, which will improve the understanding of linkages between environmental media of the Arctic, as well as links to the global problem of litter and MP pollution.

Lack of knowledge on levels and trends of litter and microplastics in the Arctic, is limiting our understanding of the sources, transport, fate, and effects is hampering global activities aimed at reducing litter and microplastics in the environment. To obtain a holistic view to managing litter and microplastics in the Arctic, we considered the current state of knowledge and methods for litter and microplastics monitoring in eleven environmental compartments representing the marine, freshwater, terrestrial, and atmospheric environments. Based on available harmonized methods, and existing data in the Arctic, we recommend prioritization of implementing litter and microplastics monitoring in the Arctic in four Priority 1 compartments—water, aquatic sediments, shorelines, and seabirds. One or several of these compartments should be monitored to provide benchmark data for litter and microplastics in the Arctic and, in the future, data on spatial and temporal trends. For the other environmental compartments, methods should be refined for future sources and surveillance monitoring, as well as monitoring of effects. Implementation of the monitoring activities should include community-based local components where possible. While organized as national and regional programs, monitoring of litter and microplastics in the Arctic should be coordinated, with a view to future pan-Arctic assessments.

Few studies have been published on occurrence and distribution on microplastics (MPs) in invertebrates from the Arctic. We still need to develop harmonised methods to enable good comparison between studies taking into account recovery rates, size ranges, shapes and polymer types. Here, we review studies on MPs in invertebrates from the Arctic and present suggestions on sampling protocols and potential indicator species. Since information on MPs in Arctic invertebrates is vastly lacking, we recommend to at least include suspension feeding bivalves like mussels in monitoring programmes to function as indicator species in the Arctic. Mussels have also been suggested as indicator species for MP monitoring in coastal regions further south. Although we recognise the challenge with particle selection and egestion in mussels as well as the relatively low concentrations of MPs in Arctic waters, uptake levels seem to represent recent exposures. More research is needed to understand these selection processes and how they affect the bioaccumulation processes. Future research should include studies on whether different functional groups of invertebrates have different exposures to MPs, e.g., if there are differences between sessile versus motile species or different feeding strategies. More knowledge on monitoring strategies for pelagic and benthic species is needed.

The application of fluorescence microscopy in cell biology often generates a huge amount of imaging data. Automated whole cell segmentation of such data enables the detection and analysis of individual cells, where a manual delineation is often time consuming, or practically not feasible. Furthermore, compared to manual analysis, automation normally has a higher degree of reproducibility. CellSegm , the software presented in this work, is a Matlab based command line software toolbox providing an automated whole cell segmentation of images showing surface stained cells, acquired by fluorescence microscopy. It has options for both fully automated and semi-automated cell segmentation. Major algorithmic steps are: (i) smoothing, (ii) Hessian-based ridge enhancement, (iii) marker-controlled watershed segmentation, and (iv) feature-based classfication of cell candidates. Using a wide selection of image recordings and code snippets, we demonstrate that CellSegm has the ability to detect various types of surface stained cells in 3D. After detection and outlining of individual cells, the cell candidates can be subject to software based analysis, specified and programmed by the end-user, or they can be analyzed by other software tools. A segmentation of tissue samples with appropriate characteristics is also shown to be resolvable in CellSegm . The command-line interface of CellSegm facilitates scripting of the separate tools, all implemented in Matlab , offering a high degree of flexibility and tailored workflows for the end-user. The modularity and scripting capabilities of CellSegm enable automated workflows and quantitative analysis of microscopic data, suited for high-throughput image based screening.

Acute lung injury (ALI) is associated with increased vascular permeability, leukocyte recruitment, and pro‐inflammatory mediator release. We investigated the role of the metalloproteinase ADAM17 in endotoxin‐induced ALI with focus on endothelial ADAM17. In vitro , endotoxin‐mediated induction of endothelial permeability and IL‐8‐induced transmigration of neutrophils through human microvascular endothelial cells required ADAM17 as shown by inhibition with GW280264X or shRNA‐mediated knockdown. In vivo , ALI was induced by intranasal endotoxin‐challenge combined with GW280264X treatment or endothelial adam17 ‐knockout. Endotoxin‐triggered upregulation of ADAM17 mRNA in the lung was abrogated in knockout mice and associated with reduced ectodomain shedding of the junctional adhesion molecule JAM‐A and the transmembrane chemokine CX3CL1. Induced vascular permeability, oedema formation, release of TNF‐α and IL‐6 and pulmonary leukocyte recruitment were all markedly reduced by GW280264X or endothelial adam17 ‐knockout. Intranasal application of TNF‐α could not restore leukocyte recruitment and oedema formation in endothelial adam17 ‐knockout animals. Thus, activation of endothelial ADAM17 promotes acute pulmonary inflammation in response to endotoxin by multiple endothelial shedding events most likely independently of endothelial TNF‐α release leading to enhanced vascular permeability and leukocyte recruitment.

Neuropeptide- and hormone-containing secretory granules (SGs) are synthesized at the trans-Golgi network (TGN) as immature secretory granules (ISGs) and complete their maturation in the F-actin-rich cell cortex. This maturation process is characterized by acidification-dependent processing of cargo proteins, condensation of the SG matrix and removal of membrane and proteins not destined to mature secretory granules (MSGs). Here we addressed a potential role of Rab3 isoforms in these maturation steps by expressing their nucleotide-binding deficient mutants in PC12 cells. Our data show that the presence of Rab3D(N135I) decreases the restriction of maturing SGs to the F-actin-rich cell cortex, blocks the removal of the endoprotease furin from SGs and impedes the processing of the luminal SG protein secretogranin II. This strongly suggests that Rab3D is implicated in the subcellular localization and maturation of ISGs.