Search

[Display omitted] • Methylated arsenicals were present in urban dust. • Urban dust exhibited a high abundance of ABGs. • Urban dust displayed a high diversity of microbes involved in arsenic methylation. • Season exerted significant impacts on ARGs and arsenic methylation microbes. Microbially-mediated arsenic biotransformation plays a pivotal role in the biogeochemical cycling of arsenic; however, the presence of arsenic biotransformation genes (ABGs) in urban dust remains unclear. To investigate the occurrence and spatiotemporal distributions of ABGs, a total of one hundred and eighteen urban dust samples were collected from different districts of Xiamen city, China in summer and winter. Although inorganic arsenic species, including arsenate [As(V)] and arsenite [As(III)], were found to be predominant, the methylated arsenicals, particularly trimethylarsine oxide [TMAs(V)O] and dimethylarsenate [DMAs(V)], were detected in urban dust. Abundant ABGs were identified in urban dust via AsChip analysis (a high-throughput qPCR chip for ABGs), of which As(III) S -adenosylmethionine methyltransferase genes (arsM), As(V) reductase genes (arsC), As(III) oxidase genes (aioA), As(III) transporter genes (arsB), and arsenic-sensing regulator genes (arsR) were the most prevalent, collectively constituting more than 90 % of ABGs in urban dust. Microbes involved in arsenic methylation were assigned to bacteria (e.g., Actinomycetes and Alphaproteobacteria), archaea (e.g., Halobacteria), and eukaryotes (e.g., Chlamydomonadaceae) in urban dust via the arsM amplicon sequencing. Temperature, a season-dependent environmental factor, profoundly affected the abundance of ABGs and the composition of microbes involved in arsenic methylation. This study provides new insights into the presence of ARGs within the urban dust. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance and electrical conductivity of Ti-6Al-4V bipolar plates used in polymer electrolyte membrane fuel cells (PEMFCs), a novel electro-conductive Ta 2 N nanoceramic coating was developed by reactive sputter-deposition using a double cathode glow discharge plasma technique. The microstructure of the coating consisted of fine equiaxed Ta 2 N grains with an average grain size of ∼13 nm, which exhibited a strong (101) preferred orientation. To explore the influence of both pH values and temperatures on the corrosion resistance of the coating, the electrochemical behaviors and electronic properties of passive films grown on the Ta 2 N coating were systematically investigated using different electrochemical techniques in simulated PEMFC operating environment. It was shown that either increasing the acidity or the temperatures of the solution, the corrosion potential (E corr ) decreased and the corrosion current density (i corr ) increased. At a given temperature or pH value, the Ta 2 N coating had a higher E corr and lower i corr as compared with uncoated Ti-6Al-4V. The results of EIS measurements showed that with increasing temperature or acidity of the solution, the resistance of the passive film (R p ) formed on the Ta 2 N coating decreased slightly, being of the order of magnitude of 10 7 Ω cm 2 , which was an order of magnitude higher than that of uncoated Ti-6Al-4V. The interfacial contact resistance (ICR) values were found to increase with increasing pH value or decreasing solution temperature, and the ICR values of the Ta 2 N coating were markedly lower than that of uncoated Ti-6Al-4V, due to the thinner thickness of passive films. Furthermore, the Ta 2 N-coated Ti-6Al-4V is more hydrophobic than bare Ti-6A1-4V, which was favorable for both the simplification of water management and improving corrosion resistance in PEMFC operating environment. [ABSTRACT FROM AUTHOR]

In addition to altered gene expression, pathological cytoskeletal dynamics in the axon are another key intrinsic barrier for axon regeneration in the central nervous system (CNS). Here, we show that knocking out myosin IIA and IIB (myosin IIA/B) in retinal ganglion cells alone, either before or after optic nerve crush, induces significant optic nerve regeneration. Combined Lin28a overexpression and myosin IIA/B knockout lead to an additive promoting effect and long-distance axon regeneration. Immunostaining, RNA sequencing, and western blot analyses reveal that myosin II deletion does not affect known axon regeneration signaling pathways or the expression of regeneration-associated genes. Instead, it abolishes the retraction bulb formation and significantly enhances the axon extension efficiency. The study provides clear evidence that directly targeting neuronal cytoskeleton is sufficient to induce significant CNS axon regeneration and that combining altered gene expression in the soma and modified cytoskeletal dynamics in the axon is a promising approach for long-distance CNS axon regeneration. • Myosin II KO in RGCs induces significant optic nerve regeneration • Myosin II KO does not affect gene transcription in RGCs • Myosin II KO reduces retraction bulbs and leads to efficient axon extension • Myosin II KO and Lin28a expression in RGCs produce long-distance axon regeneration Although modulating the neuronal cytoskeleton has been deemed a promising approach to enhance mammalian axon regeneration, only a few studies have shown convincing results, especially in the central nervous system. Wang et al. demonstrate that the deletion of non-muscle myosin II sufficiently induces significant mammalian CNS axon regeneration in vivo. [ABSTRACT FROM AUTHOR]

[Display omitted] • Season affected the communities of bacteria and fungi in urban dust. • Spatiotemporal changes in microbial assembly and interaction were detected. • Dust-borne potential bacterial pathogens in summer were higher than those in winter. • Microbes in dust have a potential threat to human health, especially to children. Community and composition of dust-borne microbes would affect human health and are regulated by microbial community assembly. The dust in kindergarten is always collected to evaluate the microbial exposure of children, yet the microbial assembly, their interactions, and potential pathogens in kindergarten dust remain unclear. Here, we aim to investigate the microbial community assembly and structures, and potential bacterial pathogens in outdoor dust of kindergartens, and reveal the factors influencing the assembly and composition of microbial community. A total of 118 urban dust samples were collected on the outdoor impervious surfaces of 59 kindergartens from different districts of Xiamen in January and June 2020. We extracted microbial genomic DNA in these dusts and characterized the microbial (i.e. , bacteria and fungi) community compositions and diversities using target gene-based (16S rRNA genes for bacterial community and ITS 2 regions for fungal community) high-throughput sequencing. Potential bacterial pathogens were identified and the interactions between microbes were determined through a co-occurrence network analysis. Our results showed the predominance of Actinobacteria and α-Proteobacteria in bacterial communities and Capnodiales in fungal communities. Season altered microbial assembly, composition, and interactions, with both bacterial and fungal communities exhibiting a higher heterogeneity in summer than those in winter. Although stochastic processes predominated in bacterial and fungal community assembly, the season-depended environmental factors (e.g., temperature) and interactions between microbes play important roles in dust microbial community assembly. Potential bacterial pathogens were detected in all urban dust, with significantly higher relative abundance in summer than that in winter. These results indicated that season exerted more profound effects on microbial community composition, assembly, and interactions, and suggested the seasonal changes of potential risk of microbes in urban dust. Our findings provide new insights into microbial community, community assembly, and interactions between microbes in the urban dust, and indicate that taxa containing opportunistic pathogens occur commonly in urban dust. [ABSTRACT FROM AUTHOR]