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The assessment of microplastic (MP) pollution in urban areas is essential considering its abundance in freshwater, particularly due to urban wet weather discharge. The precise sources of MPs must be identified to better understand its characteristics. This study examines the relationship between MP pollution in detention basin sediments and land use in the investigated catchments. The study of stormwater management infrastructure, mainly in detention basins, has enabled the quantification of MP abundance in sediments conveyed by stormwater in urban areas. Sediment sampling was conducted in ten detention basins and one combined sewer overflow (CSO) structure in the Lyon metropolitan area, France. These basins correspond to stormwater outlets of representative urban catchment areas. MP extraction involves densimetric separation and organic matter degradation. MPs were then characterized using micro-Fourier infrared spectroscopy and siMPle software. This protocol identified MPs between 50 and 500 μm in the study sites. This study highlights the high abundance in the collected sediment samples, ranging from 2,525 to 1,218,82 MP kg−1 by dry weight sediment. The MPs found have a median size around 115 μm, making them very small MPs that are mainly composed of polypropylene followed by polyethylene and polystyrene or polyethylene terephthalate. The abundance of MPs in sediments is associated with the land use type. Catchments in predominantly industrial and commercial zones were more significantly polluted with MPs compared with those in predominantly agricultural or heterogeneous zones. Finally, statistical analyses revealed links between sedimentary and urban parameters and MPs concentrations. Several recommendations are given for future research, notably concerning the analyzing of stormwater sediments to understand the sources of MP pollution. [Display omitted] • Stormwater basin sediments act as indicators of MP pollution in urban catchments. • Industrial and commercial areas show high microplastic (MP) levels. • Urban and industrial sediments are more polluted than those in agricultural basins. • Statistical models confirm a positive link between organic matter and MP abundance. • Urban sediment management is crucial for river and groundwater pollution mitigation. [ABSTRACT FROM AUTHOR]

The quantification of microplastic (MP) pollution in rivers is often constrained by a lack of historical data on a multi-decadal scale, which hinders the evaluation of public policies. In this study, MP contents and trends were analyzed in dated sediment cores sampled upstream and downstream of a large metropolis, in environmental deposits that exhibited consistent sedimentation patterns from the 1980s to 2021. After a thorough sedimentological analysis, MPs were quantified in samples by micro Fourier Transform InfraRed spectroscopy (μFTIR imaging) and a density separation and organic matter digestion procedure. Microplastics recorded in the upstream core are relatively ubiquitous all along the dated sequence. The results also confirmed a sever increase of microplastics levels in the downstream core, by one order of magnitude, and an increase of polymer types. Polypropylene, polyethylene, and polystyrene represent ubiquitous contamination and were predominant at the two stations, whereas polyvinyl chloride and polytetrafluoroethylene were suspected to be abundant at the downstream station, but were not detected at the upstream station. Their presence could be linked to local contamination from specific industrial sources that manufactured and utilized these polymers. Surprisingly, in the downstream station sediment has recorded a relative improvement in polymers associated with industrial sources since the 2000s and, to a lesser extent, for ubiquitous ones since the 2010s. This trend of mitigation diverges from that of global assessments, that assume uncontrolled MP pollution, and suggest that European Union wastewater policy and regulation on industrial discharges have positively influenced water quality, and certainly also on MPs. However, the accumulation of microplastics remains high in recent deposits and raises the emerging concern of the long-term management of these reservoirs. [Display omitted] • Microplastic trends were retraced over four decades using river sediment cores. • Downstream of the metropolis, microplastic levels were notably higher. • Polymer-type compositions reflected urban and industrial sources. • Recent trends diverged from plastic demand, suggesting source control. [ABSTRACT FROM AUTHOR]

Abstract Background Piwi-associated RNAs (piRNAs) bind transcripts from retrotransposable elements (RTE) in mouse germline cells and seemingly act as guides for genomic methylation, thereby repressing the activity of RTEs. It is currently unknown if and how Piwi proteins distinguish RTE transcripts from other cellular RNAs. During germline development, the main target of piRNAs switch between different types of RTEs. Using the piRNA targeting of RTEs as an indicator of RTE activity, and considering the entire population of genomic RTE loci along with their age and location, this study aims at further elucidating the dynamics of RTE activity during mouse germline development. Results Due to the inherent sequence redundancy between RTE loci, assigning piRNA targeting to specific loci is problematic. This limits the analysis, although certain features of piRNA targeting of RTE loci are apparent. As expected, young RTEs display a much higher level of piRNA targeting than old RTEs. Further, irrespective of age, RTE loci near protein-coding coding genes are targeted to a greater extent than RTE loci far from genes. During development, a shift in piRNA targeting is observed, with a clear increase in the relative piRNA targeting of RTEs residing within boundaries of protein-coding gene transcripts. Conclusions Reanalyzing published piRNA sequences and taking into account the features of individual RTE loci provide novel insight into the activity of RTEs during development. The obtained results are consistent with some degree of proportionality between what transcripts become substrates for Piwi protein complexes and the level by which the transcripts are present in the cell. A transition from active transcription of RTEs to passive co-transcription of RTE sequences residing within protein-coding transcripts appears to take place in postnatal development. Hence, the previously reported increase in piRNA targeting of SINEs in postnatal testis development does not necessitate widespread active transcription of SINEs, but may simply be explained by the prevalence of SINEs residing in introns.

Abstract Background Retrotransposons are transposable elements that proliferate within eukaryotic genomes through a process involving reverse transcription. The numbers of retrotransposons within genomes and differences between closely related species may yield insight into the evolutionary history of the elements. Less is known about the ongoing dynamics of retrotransposons, as analysis of genome sequences will only reveal insertions of retrotransposons that are fixed - or near fixation - in the population or strain from which genetic material has been extracted for sequencing. One pre-requisite for retrotransposition is transcription of the elements. Given their intrinsic sequence redundancy, transcriptome-level analyses of transposable elements are scarce. We have used recently published transcriptome data from the fission yeast Schizosaccharomyces pombe to assess the ability to detect and describe transcriptional activity from Long Terminal Repeat (LTR) retrotransposons. LTR retrotransposons are normally flanked by two LTR sequences. However, the majority of LTR sequences in S. pombe exist as solitary LTRs, i.e. as single terminal repeat sequences not flanking a retrotransposon. Transcriptional activity was analysed for both full-length LTR retrotransposons and solitary LTRs. Results Two independent sets of transcriptome data reveal the presence of full-length, polyadenylated transcripts from LTR retrotransposons in S. pombe during growth phase in rich medium. The redundancy of retrotransposon sequences makes it difficult to assess which elements are transcriptionally active, but data strongly indicates that only a subset of the LTR retrotransposons contribute significantly to the detected transcription. A considerable level of reverse strand transcription is also detected. Equal levels of transcriptional activity are observed from both strands of solitary LTR sequences. Transcriptome data collected during meiosis suggests that transcription of solitary LTRs is correlated with the transcription of nearby protein-coding genes. Conclusions Presumably, the host organism negatively regulates proliferation of LTR retrotransposons. The finding of considerable transcriptional activity of retrotransposons suggests that part of this regulation is likely to take place at a post-transcriptional level. Alternatively, the transcriptional activity may signify a hitherto unrecognized activity level of retrotransposon proliferation. Our findings underline the usefulness of transcriptome data in elucidating dynamics in retrotransposon transcription.

The phylogenetic relationships and species limits within the chiropteran family Miniopteridae are poorly known in mainland Africa. Recent systematic studies in Madagascar have shown that this is a species-rich family, yet only eight species are currently recognized or hypothesized for continental Africa. Based on partial cytochrome b sequences and morphometric analysis, we describe a new species of Miniopterus that is endemic to a restricted, montane region of Liberia and Guinea. Furthermore, the taxonomic status of the West African Miniopterus schreibersii villiersi is resolved and shown to be a distinct species, M. villiersi, that is not closely related to M. schreibersii. Finally, the species M. inflatus is revealed to be paraphyletic, with the central African rainforest populations apparently not closely related to the savanna forms in eastern and southern Africa. Based on the results of this study, the number of Miniopterus species in Africa has increased from eight to 11, with more cryptic species likely to be discovered. [ABSTRACT FROM AUTHOR]

Bed sediments and a dated sediment core were collected upstream and downstream from the city of Lyon (France) to assess the spatial and temporal trends of contamination by per- and polyfluoroalkyl substances (PFASs) in this section of the Rhône River. Upstream from Lyon, concentrations of total PFASs (ΣPFASs) in sediments are low (between 0.19 and 2.6 ng g−1 dry weight - dw), being characterized by a high proportion of perfluorooctane sulfonate (PFOS). Downstream from Lyon, and also from a fluoropolymer manufacturing plant, ΣPFASs concentrations reach 48.7 ng g−1 dw. A gradual decrease of concentrations is reported at the coring site further downstream (38 km). Based on a dated sediment core, the temporal evolution of PFASs is reconstructed from 1984 to 2013. Prior to 1987, ΣPFASs concentrations were low (≤2 ng g−1 dw), increasing to a maximum of 51 ng g−1 dw in the 1990s and then decreasing from 2002 to the present day (∼10 ng g−1 dw). In terms of the PFAS pattern, the proportion of perfluoroalkyl sulfonic acids (PFSAs) has remained stable since the 1980s (∼10%), whereas large variations are reported for carboxylic acids (PFCAs). Long chain- (C > 8) PFCAs characterized by an even number of perfluorinated carbons represent about 74% of the total PFAS load until 2005. However, from 2005 to 2013, the relative contribution of long chain- (C > 8) PFCAs with an odd number of perfluorinated carbons reaches 80%. Such changes in the PFAS pattern likely highlight a major shift in the industrial production process. This spatial and retrospective study provides valuable insights into the long-term contamination patterns of PFAS chemicals in river basins impacted by both urban and industrial activities. Image 1 • Upstream-downstream PFAS concentration gradient in bed sediments in the Rhône River. • Reconstruction of temporal trends of PFAS contamination using a sediment core. • Evidence of global PFSA background levels. • Release of long-chain PFCAs from a point source into the river. • Change of PFCA pattern through time likely reflects changes in production processes. [ABSTRACT FROM AUTHOR]

The mammalian respiratory chain complexes I, III 2 , and IV (CI, CIII 2 , and CIV) are critical for cellular bioenergetics and form a stable assembly, the respirasome (CI-CIII 2 -CIV), that is biochemically and structurally well documented. The role of the respirasome in bioenergetics and the regulation of metabolism is subject to intense debate and is difficult to study because the individual respiratory chain complexes coexist together with high levels of respirasomes. To critically investigate the in vivo role of the respirasome, we generated homozygous knockin mice that have normal levels of respiratory chain complexes but profoundly decreased levels of respirasomes. Surprisingly, the mutant mice are healthy, with preserved respiratory chain capacity and normal exercise performance. Our findings show that high levels of respirasomes are dispensable for maintaining bioenergetics and physiology in mice but raise questions about their alternate functions, such as those relating to the regulation of protein stability and prevention of age-associated protein aggregation. [Display omitted] • Three amino acids (EED) in UQCRC1 of complex III 2 control respirasome stability • Homozygous Uqcrc1 delEED knockin mice have drastically reduced respirasome levels • Profound depletion of respirasomes does not impair oxidative phosphorylation • Mice with a profound depletion of respirasomes have apparently normal physiology The role of the mammalian respirasome, a stable assembly of a complete respiratory chain, is much debated. Milenkovic et al. have generated knockin mice with a profound depletion of respirasomes. Very unexpectedly, the mutant mice have preserved oxidative phosphorylation capacity and physiology, arguing that respirasomes may be dispensable for normal bioenergetics. [ABSTRACT FROM AUTHOR]

A teacher remembers the importance of what he learned about foreign cultures from sources other than the classroom instructional materials, particularly as culture was made real for him through literature. (MSE)

This article underlines the interest of French collectors and investors for objects from the Indian Ocean, as early as the first quarter of the 17th century. Thanks to the network of intermediaries that Fabri de Peiresc structured, he is one of those who have first contributed to develop the interest for Indian curiosities. Whereas nobility and financial circles in Paris favor the Dutch “supply chain” and, in this process, the very criteria for acquiring these exotic objects are changing during the Century: more than exotic curiosities to be displayed in cabinets, which the buyers are looking for are precious materials, particularly valued for their financial liquidity.