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Abstract Enzymes that facilitate the local deposition of electron dense reaction products have been widely used as labels in electron microscopy (EM) for the identification of synaptic contacts in neural tissue. Peroxidases, in particular, can efficiently metabolize 3,3′-diaminobenzidine tetrahydrochloride hydrate (DAB) to produce precipitates with high contrast under EM following heavy metal staining, and can be genetically encoded to facilitate the labeling of specific cell-types or organelles. Nevertheless, the peroxidase/DAB method has so far not been reported to work in a multiplexed manner in combination with 3D volume EM techniques (e.g. Serial blockface electron microscopy, SBEM; Focused ion beam electron microscopy, FIBSEM) that are favored for the large-scale ultrastructural assessment of synaptic architecture However, a recently described peroxidase with enhanced enzymatic activity (dAPEX2) can efficienty deposit EM-visible DAB products in thick tissue without detergent treatment opening the possibility for the multiplex labeling of genetically defined cell-types in combination with volume EM methods. Here we demonstrate that multiplexed dAPEX2/DAB tagging is compatible with both FIBSEM and SBEM volume EM approaches and use them to map long-range genetically identified synaptic inputs from the anterior cingulate cortex to the periaqueductal gray in the mouse brain.

Water pollution and control are important issues of our lasting concern. Environmental media often contains a variety of compounds. Tritium is widely present in nature due to human activities. As an endocrine disruptor, genistein is widely found in water body. Will it cause damage when combined with tritiated water and genistein? In this study, Zebrafish embryos were randomly divided into 4 groups: blank control group (simple E3 medium), tritiated water exposure group (tritiated water with a final concentration of 3.7*102Bq/mL in the medium), and genistein exposure group (the final concentration of 1.4 mg/L genistein in the medium) and the combined exposure group of tritiated water and genistein (3.7*102 Bq/mL tritium water +1.4 mg/L genistein). The results show that tritiated water with 3.7*102 Bq/ml exposure alone did not affect the development of zebrafish embryos. However, the survival rate, hatching rate and heart rate of zebrafish larvae decreased combined exposure with genistein, and the abnormality rate and apoptotic cells in the embryos and the level of oxidative stress increased. The results of RNA sequencing showed that the combined exposure of tritiated water and genistein affected the gene expression of zebrafish embryos. Differential genes were mainly enriched in many pathways, such as p53 signaling pathway, steroid hormone biosynthesis, PPAR signaling pathway, metabolism of xenobiotics by cytochrome P450. The results of qRT-PCR and gene knockout experiment showed that cyp19a1b gene may plays an important role in the toxic effects of combined exposure.

Scientific assessment of water resources carrying capacity (WRCC) is the basis for implementing water resources protection measures. To make the evaluation more objective and reasonable, this study created a WRCC evaluation method based on R-clustering-variance coefficient method coupled with cloud model (RCC) for the state study of WRCC in a specific region. The study collected and summarized the available indicators through the review of existing studies to build a database of extensively selected indicators, and also combined with the characteristics of the study area to construct the initial indicators database. Then the indicators were categorized into 12 factor layers under the concept of water resources carrying subjects and objects, and the R clustering-variance coefficient method was introduced to screen the indicators to construct a concise and effective evaluation index system. Finally, combined with the cloud model to identify the comprehensive state of WRCC, the quantitative expression of WRCC was realized. Taking Henan Province of China as the research area, a total of 81 available indicators were collected, and an evaluation index system composed of 30 indicators was constructed after screening. During the evaluation years of 2005–2017, the WRCC level in Henan Province gradually raised from level IV (overload) to level II (weakly bearable), and the results of the study were stable and consistent with the changing trend of existing studies. The study can provide new ideas for the evaluation indicators selection and quantitative evaluation of water resources carrying capacity or other carrying capacity for a specific county, city, or provincial study area.

Mitochondrial coding genes involved in the oxidative phosphorylation pathway play vitally important roles in energy production and thermal adaptation. Investigating the underlying molecular mechanism of mitochondrial adaptive evolution is crucial for understanding biodiversity and ecological radiation. In this study, we collated population genetic studies of marine fish species in the northwestern Pacific based on mitochondrial cytochrome b gene sequences, to investigate whether similar patterns could be detected in mitochondrial adaptive evolution. After filtering, nine studies containing eight marine fish species (Ammodytes personatus, Boleophthalmus pectinirostris, Larimichthys polyactis, Mugil cephalus, Pampus argenteus, Platycephalus sp.1, Sebastiscus marmoratus, and Trachidermus fasciatus) belonging to eight different families were retained. Multiple codon-based approaches were used to identify potential sites under selection in each species. By comparison, our results showed that the posterior part of the mitochondrial cytochrome b gene (particularly codon 372 and its neighboring sites) seemed to be involved in the adaptive evolution process, suggesting potential genetic similarity among distantly related species. We also summarized four types of adaptive patterns in the reviewed species, and suggest that the level of genetic differentiation and mitochondrial adaptive evolution might be correlated. Further studies are needed to confirm such relationship by detecting RNA-level evidence and investigating more species and samples.

Mg-5Li-1Al-0.5Y alloy was rolled with different directions. The microstructure, mechanical properties and texture of the specimens were investigated with optical microscope, tensile tester and X-ray diffraction. The results show that changing rolling directions can refine the grain size of as-rolled alloys. Meanwhile, rolling directions have an obvious influence on the mechanical properties and texture of Mg-5Li-1Al-0.5Y alloy, thus affecting the anisotropy of the alloy. The sheet, of which the RD (rolling direction) and ND (normal direction) are both changed between two passes, possesses the smallest anisotropy. From the texture results, changing rolling directions reduces the maximum pole density, making the highest point distribution region excursion and the highest point distributes more scatteredly.