Sublethal Toxic Effects and Induction of gGutathione S-transferase by Short-Chain Chlorinated Paraffins (SCCPs) and C-12 alkane (dodecane) in Xenopus laevis Frog Embryos

Short chain chlorinated paraffins (SCCPs) are important industrial chemicals with high persistence in the environment but poorly characterized ecotoxicological effects. We studied embryotoxic effects of commercial mixture of SCCP (carbon length C-12, 56% of chlorine; CP56-12) and non-chlorinated n-alkane (dodecane, C-12) in the 96h Frog Embryo Teratogenesis Assay - Xenopus (FETAX). Only weak lethal effects were observed for both substances (the highest tested concentration 500 mg/L of both chemicals caused up to 11% mortality). On the other hand, we observed developmental malformations and reduced embryo growth at 5 mg/l and higher concentrations. However, the effects were not related to chlorination pattern as both SCCPs and dodecane induced qualitatively similar effects. SCCPs also significantly induced phase II detoxification enzyme glutathione S-transferase (GST) in Xenopus laevis embryos even at 0.5 mg/L, and this biomarker might be used as another early warning of chronic toxic effects. Our results newly indicate significant developmental toxicity of both SCCPs and n-dodecane to aquatic organisms along with inductions of specific biochemical toxicity mechanisms

Corridor Talk: Conservation Humanities and the Future of Europe’s National Parks

Corridor Talk: Conservation Humanities and the Future of Europe’s National Parks is a DFG-AHRC funded project at the Rachel Carson Center for Environment and Society at LMU Munich (Germany), and the University of Leeds (UK). The project focuses on three European transboundary national park areas: the Pyrenees, the Bavarian Forest and Šumava, and the Wadden Sea Biosphere Reserve. It uses comparative literature, visual ethnography and environmental history methodologies to connect insights into human culture, values, history, and behaviour that are central to humanities and social sciences research to nature conservation science and practice. It aims to foster a conservation that is more culturally aware, more aware of human behaviour and values, and more aware of the ethical complexities of its work by applying the “corridor talk” metaphor in three ways: to address and support the material ecological corridors that link protected sites; to address and support the symbolic corridors that connect governance and cultural perspectives on protected sites; and to bring humanities research into discussions on nature conservation

Author Correction: Low oral dose of 4-methylumbelliferone reduces glial scar but is insufficient to induce functional recovery after spinal cord injury

Correction to: Scientific Reports, published online 06 November 2023 The original version of this Article contained errors. As a result of incorrect figure assembly, in Figure 6D the image of Luxol Fast Blue staining for the +2 mm level was a duplication of the 0 mm level. Additionally, in Figure 7E the images were inadvertently switched for ‘Placebo’ and ‘4-MU’. The original Figures 6 and 7 and their accompanying legends appear below. (Figure presented.) (Figure presented.) 4-MU treatment reduced glial scar area surrounding the lesion site. (A) Representative fluorescent images showing lesion epicentre (0 mm), above (− 4, − 2 mm) and below (+ 2, + 4 mm) the lesion, stained for glial fibrillary acidic protein (GFAP) in placebo and 4-MU treated group with chronic spinal cord injury. Dotted lines show the border area of the lesion cavity in 4-MU treated group and GFAP positive area in placebo group. Scale bar: 200 µm. Diagram of uninjured spinal cord at top left showing the direction of the cross section in (A), created with BioRender.com; (B) magnified images (yellow square in A) showing structural change of the glial scar tissue after 4-MU treatment compared to placebo treated animals. Scale bar 30 µm; (C) bar graph showing area of the glial scar around the central cavity performed in the GFAP stained histochemical images using ImageJ software. Values are plotted as mean ± SEM; ****p < 0.0001 by two-way ANOVA, Sidak post-hoc test. (n = 4 animals per group). (D) Representative images of Luxol Fast Blue staining showing the lesion extension in a rostro-caudal direction. Scale bar 200 µm. 4-MU treatment leads to changes of cell and ECM composition around the lesion scar (Th8-9), above (Th5-6) and below (Th10-11) lesion. (A–E) Representative confocal images showing the 4-MU-mediated effect on scar-forming cells and components using different markers—(A) nestin and GFAP were used to visualise scar-forming astrocytes. (B) Iba-1 to visualise microglia/macrophages. (C) NG2 to visualise oligodendrocyte progenitor cells (OPCs). (D) CS-56 to examine the changes in CS sulfations. (E) Collagen 1a to visualise meninges and fibroblasts. All insets show magnified views of the staining. Scale bar 200 µm for the overview image and 50 µm for the insets. (F) Quantification of (A–E). Bar graphs show intensities per section throughout the spinal cord, except for Iba-1 staining where the number of Iba-1 positive cells per mm was counted. Individual data are shown with their mean ± SEM (n = 3 animals per group). p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, by two-way ANOVA, Sidak's multiple comparison test. The original Article has been corrected

A 4-gigabase physical map unlocks the structure and evolution of the complex genome of Aegilops tauschii, the wheat D-genome progenitor

The current limitations in genome sequencing technology require the construction of physical maps for high-quality draft sequences of large plant genomes, such as that of Aegilops tauschii, the wheat D-genome progenitor. To construct a physical map of the Ae. tauschii genome, we fingerprinted 461,706 bacterial artificial chromosome clones, assembled contigs, designed a 10K Ae. tauschii Infinium SNP array, constructed a 7,185-marker genetic map, and anchored on the map contigs totaling 4.03 Gb. Using whole genome shotgun reads, we extended the SNP marker sequences and found 17,093 genes and gene fragments. We showed that collinearity of the Ae. tauschii genes with Brachypodium distachyon, rice, and sorghum decreased with phylogenetic distance and that structural genome evolution rates have been high across all investigated lineages in subfamily Pooideae, including that of Brachypodieae. We obtained additional information about the evolution of the seven Triticeae chromosomes from 12 ancestral chromosomes and uncovered a pattern of centromere inactivation accompanying nested chromosome insertions in grasses. We showed that the density of noncollinear genes along the Ae. tauschii chromosomes positively correlates with recombination rates, suggested a cause, and showed that new genes, exemplified by disease resistance genes, are preferentially located in high-recombination chromosome regions

The improved assembly of 7DL chromosome provides insight into the structure and evolution of bread wheat

Wheat is one of the most important staple crops worldwide and also an excellent model species for crop evolution and polyploidization studies. The breakthrough of sequencing the bread wheat genome and progenitor genomes lays the foundation to decipher the complexity of wheat origin and evolutionary process as well as the genetic consequences of polyploidization. In this study, we sequenced 3286 BACs from chromosome 7DL of bread wheat cv. Chinese Spring and integrated the unmapped contigs from IWGSC v1 and available PacBio sequences to close gaps present in the 7DL assembly. In total, 8043 out of 12 825 gaps, representing 3 491 264 bp, were closed. We then used the improved assembly of 7DL to perform comparative genomic analysis of bread wheat (Ta7DL) and its D donor, Aegilops tauschii (At7DL), to identify domestication signatures. Results showed a strong syntenic relationship between Ta7DL and At7DL, although some small rearrangements were detected at the distal regions. A total of 53 genes appear to be lost genes during wheat polyploidization, with 23% (12 genes) as RGA (disease resistance gene analogue). Furthermore, 86 positively selected genes (PSGs) were identified, considered to be domestication‐related candidates. Finally, overlapping of QTLs obtained from GWAS analysis and PSGs indicated that TraesCS7D02G321000 may be one of the domestication genes involved in grain morphology. This study provides comparative information on the sequence, structure and organization between bread wheat and Ae. tauschii from the perspective of the 7DL chromosome, which contribute to better understanding of the evolution of wheat, and supports wheat crop improvement

A chromosome conformation capture ordered sequence of the barley genome

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Nestedness of Ectoparasite-Vertebrate Host Networks

Determining the structure of ectoparasite-host networks will enable disease ecologists to better understand and predict the spread of vector-borne diseases. If these networks have consistent properties, then studying the structure of well-understood networks could lead to extrapolation of these properties to others, including those that support emerging pathogens. Borrowing a quantitative measure of network structure from studies of mutualistic relationships between plants and their pollinators, we analyzed 29 ectoparasite-vertebrate host networks—including three derived from molecular bloodmeal analysis of mosquito feeding patterns—using measures of nestedness to identify non-random interactions among species. We found significant nestedness in ectoparasite-vertebrate host lists for habitats ranging from tropical rainforests to polar environments. These networks showed non-random patterns of nesting, and did not differ significantly from published estimates of nestedness from mutualistic networks. Mutualistic and antagonistic networks appear to be organized similarly, with generalized ectoparasites interacting with hosts that attract many ectoparasites and more specialized ectoparasites usually interacting with these same “generalized” hosts. This finding has implications for understanding the network dynamics of vector-born pathogens. We suggest that nestedness (rather than random ectoparasite-host associations) can allow rapid transfer of pathogens throughout a network, and expand upon such concepts as the dilution effect, bridge vectors, and host switching in the context of nested ectoparasite-vertebrate host networks