 Natural textile fibres dominate freshwater and atmospheric fibre populations  Environmental concentrations, of textile fibres vary greatly through time and space  Upstream textile fibre concentrations can exceed that of the Marne River in Paris  Atmospheric deposition is a potential source of textile fibres in remote locations  Atmospheric deposition of textile fibres is not correlated to precipitation

The presence of microplastic particles (<5 mm) in the environment has generated considerable concern across public, political, and scientific platforms. However, the diversity of microplastics that persist in the environment poses complex analytical challenges for our understanding of their prevalence. The use of the dye Nile red to quantify microplastics is increasingly common. However, its use in microplastic analysis rarely accounts for its affinity with the breadth of particles that occur in environmental samples. Here we examine Nile red's ability to stain a variety of microplastic particles and common natural and anthropogenic particles found in environmental samples. To better constrain microplastic estimates using Nile red, we test the co-application of a second stain that binds to biological material, 4′,6-diamidino-2-phenylindole (DAPI). We test the potential inflation of microplastic estimates using Nile red alone by applying this costaining approach to samples of water and freshwater. The use of Nile red dye alone resulted in a maximum 100% overestimation of microplastic particles. These findings are of particular significance for the public dissemination of findings from an emotive field of study.

Previous studies have shown that binding of interleukin 1 (IL-1) to its receptor and intracellular processing of the IL-i/IL-i receptor complex appear to be different in Band T-lymphocyte cell lines. In this study we used a B-lymphoid cell line, 70Z/3, and T-lymphoid cell line, EL-4 6.1 C10, to explore further the differences that exist between IL-1 receptors on cells of B and T lineage. We show that a monoclonal antibody against the IL-1 receptor on EL-4 cells does not bind to the IL-1 receptor on 70Z/3 cells. This rinding suggests that there are structural differences in the extracellular domains of the IL-1 receptors on the two cell lines. Furthermore, affinity crosslinking showed that the molecular mass of the IL-1 receptor on EL-4 is 87 kDa, whereas that of 70Z/3 is significantly lower (66 kDa). Activation of phospholipid/Ca2+-dependent protein kinase, protein kinase C, by phorbol 12-myristate 13-acetate (PMA) greatly reduced the number ofIL-1 binding sites on 70Z/3. But, in sharp contrast, PMA had no effect on surface IL-1 receptor expression on EL-4 cells despite having an equally potent effect in activating protein kinase C. The different effects of protein kinase C suggest that the cytoplasmic domains of the IL-1 receptors in 70Z/3 and EL-4 may also be different. Lastly, a probe containing the entire coding region of the murine T-cell IL-1 receptor hybridized under high stringency conditions with mRNA from EL-4 cells but not with mRNA from 70Z/3 cells. Taken together, the observations made in this study suggest that major structural differences exist between the IL-1 receptors on B and T lymphocytes.Interleukin 1 (IL-1) is a polypeptide hormone produced by various cell types. IL-1 initiates a diverse range of biological effects by binding to specific surface receptors (for review, see ref. 1). The pre-B-lymphocyte cell line 70Z/3 and the T-lymphoma cell line EL-4 have proven to be useful systems to study the biological effects of IL-1 (2-5). 70Z/3 cells have receptors whose binding properties are significantly different from the IL-1 receptors (IL-lRs) on EL-4 cells (5-7). After binding to its receptor IL-1 is internalized and quickly degraded by 70Z/3 but not by 6,8). In this study we set out to determine what other differences might exist between the IL-iRs in the two cell lines. MATERIALS AND METHODSCell Lines. Murine pre-B-lymphoid cell line 70Z/3 and murine thymoma EL-4 6.1 C10 were grown in complete RPMI 1640 medium supplemented with 5% fetal calf serum, 2 mM glutamine, 50 ,uM mercaptoethanol, penicillin (100 units/ml), and streptomycin (0.01%) at 370C in a 5% C02/ 95% air atmosphere.Reagents. Recombinant human IL-la was produced in Escherichia coli as described (9). IL-la was labeled with Na251I using a chloramine-T method as described (10). The crosslinking agent dithiobis(succinimidylpropionate) was purchased from Pierce. Dibutyl phthalate and bisphthalate oils were obtained from Kodak.Preparation and Radiolabeling of Anti-EL4R Antibody. The monoclonal anti-IL-lR antibody (M5) was gener...

Plastic pollution represents one of the most salient indicators of society's impact on the environment. The microplastic component of this is ubiquitous, however, microplastic studies are seldom representative of the locations they sample. Over 12 months we explored spatiotemporal variation in microplastic prevalence across a freshwater system and in atmospheric deposition within its catchment, in one of the most temporally comprehensive studies of microplastic pollution. Microplastics were quantified in low concentrations (max 0.4 particles L -1 ) at all freshwater sites, including upstream of urban areas, and on rivers that do not receive wastewater treatment plant effluent. Extrapolated microplastic abundances at each site varied by up to 8 orders of magnitude over the course of the sampling campaign, suggesting that microplastic surveys that do not account for temporal variability misrepresent microplastic prevalence. Whilst we do not wish to underplay the potential impacts of microplastic particles in the environment, we argue that microplastic pollution needs to be placed in a more critical context, including assessment of temporal variability, to appropriately inform legislators and consumers. CapsuleThe main findings of this research are the extent to which freshwater microplastic concentrations are shown to vary with time, and the influence of this on flux calculations.

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