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Heterologous synapsis in c. elegans is regulated by meiotic double-strand breaks and crossovers

cHROMOSOMA 2021年第4期130卷 237-250页

作者： Liu, Hanwenheng Gordon, Spencer G. Rog, Ofer Univ Utah Sch Biol Sci 257 South 1400 East Salt Lake City UT 84112 USA Univ Utah Ctr Cell & Genome Sci 257 South 1400 East Salt Lake City UT 84112 USA Washington Univ Div Biol & Biomed Sci 660 South Euclid Ave St Louis MO 63110 USA

Alignment of the parental chromosomes during meiotic prophase is key to the formation of genetic exchanges, or crossovers, and consequently to the successful production of gametes. In almost all studied organisms, alignment involves synapsis: the assembly of a conserved inter-chromosomal interface called the synaptonemal complex (Sc). While the Sc usually synapses homologous sequences, it can assemble between heterologous sequences. However, little is known about the regulation of heterologous synapsis. Here, we study the dynamics of heterologous synapsis in the nematode c. elegans. We characterize two experimental scenarios: Sc assembly onto a folded-back chromosome that cannot pair with its homologous partner;and synapsis of pseudo-homologs, a fusion chromosome partnering with an unfused chromosome half its size. We observed elevated levels of heterologous synapsis when the number of meiotic double-strand breaks or crossovers were reduced, indicating that the promiscuity of synapsis is regulated by break formation or repair. In addition, our data suggests the existence of both chromosome-specific and nucleus-wide regulation on heterologous synapsis.

关键词： c elegans Heterologous synapsis Synaptonemal complex Double-strand breaks crossover

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Soil c : N : P Stoichiometry as Related to Nitrogen Addition in a Meadow Steppe of Northern china

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EURASIAN SOIL ScIENcE 2021年第10期54卷 1581-1587页

作者： Wang, X. G. Wuyunna Lu, X. T. Yang, G. J. coombs, c. E. O. Du, X. Song, Y. T. Zhang, F. J. Huo, G. W. Han, X. G. Dalian Minzu Univ Coll Environm & Resources Dalian 116600 Peoples R China Chinese Acad Sci Inst Appl Ecol CAS Key Lab Forest Ecol & Management Erguna Forest Steppe Ecotone Res Stn Shenyang 110016 Peoples R China Univ Sydney Ctr Carbon Water & Food Sch Life & Environm Sci Camden NSW 2570 Australia Chinese Acad Sci Inst Bot State Key Lab Vegetat & Environm Change Beijing 100093 Peoples R China

The concentrations and stoichiometry of soil carbon (c), nitrogen (N), and phosphorus (P) have critical implications for nutrient cycling and ecosystem function. While their high sensitivity to atmospheric N deposition is well known, it remains unclear for the soil depth-dependence of such responses to N deposition. Here, we examined the responses of soil c : N : P stoichiometry at three soil depths in the upper humus horizon (0-5, 5-10, and 10-20 cm) of Haplic chernozem (Loamic) across a gradient of urea addition rates (0, 2, 10, 20, and 50 g N m(-2) year(-1)) after five years treatments in a hay-harvest meadow steppe of northern china. We found that the effects of increasing N addition rates on the concentrations and stoichiometry of soil c, N and P did not depend on soil depth, though those parameters varied greatly across different soil layers. Across all soil depths, the concentrations of soil c and N increased with increasing N addition rates, but soil P concentration was not affected by N addition. The higher sensitivity of soil N than soil c to N enrichment resulted in decreasing soil c : N ratio across the N addition gradient, especially for the surface soil layer. Soil N : P ratio showed a positive response to the increases of N addition rates. The unbalanced responses of soil c, N, and P concentrations to N enrichment, as indicated by the decreases of soil c : N ratio and the increases of soil N : P ratio across the N addition gradient, highlighted the role of N enrichment in decoupling soil nutrient cycling in the temperate steppe.

关键词： biogeochemistry c N P ratio global change nitrogen enrichment soil layer

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co-administration of toll-like receptor (TLR)-3 agonist Poly I:c with different infectious bursal disease (IBD) vaccines improves IBD specific immune response in chicken

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VETERINARY RESEARcH cOMMUNIcATIONS 2021年第4期45卷 285-292页

作者： Kannaki, T. R. Priyanka, E. Abhilash, Manda Haunshi, Santosh ICAR Directorate Poultry Res Avian Hlth Lab Hyderabad 500030 Telangana India PV Narsimha Rao Telangana Vet Univ Dept Vet Microbiol Hyderabad 500030 India

Toll-like receptor (TLR) agonists are emerging as promising vaccine adjuvants and immunomodulators in poultry against many diseases. Infectious bursa disease (IBD) still remains as a major threat to poultry industry. Improving the vaccine mediated immune response would help in better protection against IBD virus infection. Adjuvant potential of TLR3 agonist, Polinosinic polycytidylic acid (Poly I:c) with different IBD vaccines has been analyzed in chicken in the present study. Intermediate, intermediate plus IBD vaccine, bursaplex vaccine and their respective poly I:c combinations were used for immunization of chicken. IBD specific antibody titers, bursa to body weight ratio, body weight gain and bursal lesion scores were evaluated at weekly interval in different immunization groups. Fold changes in cytokines IL-1 beta and IFN-gamma mRNA expression levels in spleen were also analyzed in different groups. Intermediate plus IBD vaccine induced significantly (P <= 0.05) higher IBD specific antibody response at 35 days of age than other groups with comparatively lower body weight gain and moderate bursal lesion score. Poly I:c co-administration with intermediate IBD vaccine and bursaplex vaccine improved the IBD specific antibody titers, better body weight gain and moderately less bursal lesion score. However, Poly I:c combination with intermediate plus IBD vaccine did not improve the specific immune response. IL-1 beta levels were up-regulated in intermediate plus and bursaplex group, whereas IFN-gamma m RNA expression levels were upregulated in intermediate IBD with Poly I:c group. In conclusion, poly I:c co-administration with intermediate IBD and bursaplex vaccine was beneficial and improved the specific immune response with least immunosuppression and bursal damage.

关键词： IBD vaccines Poly I c TLR3 agonist chicken

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Ablation behaviors and mechanism of Zrc-Sic-Si/Sic-Si double-layered coatings on c/c composite under plasma flame at 3000 °c

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cORROSION ScIENcE 2023年第1期218卷

作者： Wang, Yuqi Guo, Lingxiang Zhang, Yuyu Zhang, Xuemeng Ou, Hongkang Sun, Jia Northwestern Polytech Univ Shaanxi Key Lab Fiber Reinforced Light Composite M State Key Lab Ultra High Temp Composite Mat Xian 710072 Peoples R China Natl Univ Def Technol Sci & Technol Adv Ceram Fibers & Composites Lab Changsha 410073 Peoples R China

To improve the ablation performance of c/c composite at 3000 degrees c, a Zrc-Sic-Si/Sic-Si double-layered coatings (ZSS/SS) was prepared by slurry dipping-carbonization and gaseous silicon infiltration. During ablation, a competition between mechanical denudation and oxidation derived thickening occurred. The ZSS/SS coating possessed a superior ablation resistance showing lowest linear ablation rate of 0.53 mu m/s in 90 s with a parabolic rate constant Kp (0.053 mu m/s3). The excellent performance was attributed to good self-sealing of oxidation derived glassy, thus no micro-cracks were observed. However, the Kp became worse to be 0.131 for long-term ablation because of dominant mechanical denudation.

关键词： c c composites Polymer derived ceramic ceramic coating Ablation resistance

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Hollow structured (Ni/c)/ZnFe2O4 composite with enhanced low-frequency microwave absorption performance

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JOURNAL OF MAGNETISM AND MAGNETIc MATERIALS 2023年第1期568卷

作者： Dai, Jing-xiong Xu, Guang-liang Southwest Univ Sci & Technol State Key Lab Environm friendly Energy Mat Mianyang 621010 Peoples R China Southwest Univ Sci & Technol Sch Mat & Chem Mianyang 621010 Peoples R China Southwest Univ Sci & Technol Analyt & Testing Ctr Mianyang 621010 Peoples R China

To enhance the low-frequency (2-10 GHz) microwave absorption performance of hollow magnetic metal-carbon composites, hollow (Ni/c)/ZnFe2O4 composite was prepared by introducing submicron ZnFe2O4 into hollow Ni/ c microspheres. With the increased addition of ZnFe2O4, the low-frequency microwave absorption performance of the composites was gradually enhanced. When the addition of ZnFe2O4 was 12 wt%, the minimum reflection loss (RL) of -38.64 dB could be obtained at 5.33 GHz and the effective absorption bandwidth was 3.45 GHz. As the ZnFe2O4 addition increased to 18 wt%, the minimum RL reached -55.39 dB at 4.26 GHz and the effective absorption bandwidth was 3.82 GHz. The enhanced low-frequency microwave absorption performance can be attributed to the introduction of ZnFe2O4 improved attenuation coefficient and optimized impedance matching of the (Ni/c)/ZnFe2O4 composite. This work provides an effective idea to improve the low-frequency microwave absorption performance of hollow magnetic metal/carbon composites, and the prepared (Ni/c)/ZnFe2O4 composite can be used for microwave absorption in the low-frequency band.

关键词： Hollow structure Ni c ZnFe2O4 Microwave absorption performance Low-frequency

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Resistance of slurry aluminide coatings on pure nickel under different sulphidizing/Hot corrosion conditions at 700?c

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cORROSION ScIENcE 2023年第1期216卷

作者： Gregoire, Benjamin Montero, Xabier Galetz, Mathias c. Bonnet, Gilles Pedraza, Fernando La Rochelle Univ Lab Sci Ingn Environm UMR CNRS 7356 LaSIE Ave Michel Crepeau F-17042 La Rochelle 1 France DECHEMA Forschungsinst Theodor Heuss Allee 25 D-60486 Frankfurt Germany

A water-based slurry aluminide coating was elaborated on high-purity nickel and tested in synthetic air, synthetic air + 0.5 % SO2/SO3 and synthetic air + 0.5 % SO2/SO3 with sodium sulphate (Na2SO4) deposit at 700 degrees c. The developed coating considerably increased the oxidation-sulphidation resistance of nickel in the absence of salt through the formation of thin and adherent alumina scales. In contrast, the presence of sodium sulphate decreased the corrosion resistance. Microstructural investigations indicated that aluminium depletion and the related formation of Ni-rich oxides is mainly responsible for the onset of the corrosion attack following sul-phation reaction and fluxing mechanisms.

关键词： A Aluminium Molten salts c Oxidation Sulphidation Type II hot corrosion Fluxing mechanisms

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Stoichiometric relations of c, N, and P in urban top soils in Nanjing, china, and their biogeochemical implications

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JOURNAL OF SOILS AND SEDIMENTS 2021年第5期21卷 2154-2164页

作者： Yang, Jin-Ling Yuan, Da-Gang Zhao, Yu-Guo He, Yue Zhang, Gan-Lin Chinese Acad Sci Inst Soil Sci State Key Lab Soil & Sustainable Agr 71 East Beijing Rd Nanjing 210008 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Sichuan Agr Univ Coll Resource Chengdu 611130 Peoples R China Minist Ecol & Environm Peoples Republ China Nanjing Inst Environm Sci Nanjing 210042 Peoples R China

Purpose With increasing urban area and population, global cities are playing a more important role in the alteration of the global biogeochemical cycles. The aims of this study are to understand the concentrations and stoichiometric relations of biogenic elements (c, N, and P) in urban soils, further to reveal the effects of c, N, and P accumulation on the urban environment. Materials and methods We collected 317 surface (0-10 cm) soil samples taken from Nanjing, china, a typical city with more than 2000 years of history. These soil samples were located in different urban zones of Nanjing with different land use histories. The soil c, N, and P concentrations were determined. The stoichiometric relations of soil c, N, and P were investigated in urban soils. Meanwhile, some studies on sources of c, N, and P in diverse urban settings from literature were combined to explore the universal rule of c, N, and P cycling and their ecological and environmental effects in urban area. Results and discussion compared to rural soils, more c, N, and P are accumulated in the urban soils, which also change their stoichiometric relations. The concentrations of Oc, TN, and TP in urban top soils are 17.0 +/- 9.69 g kg(-1), 1.53 +/- 0.92 g kg(-1), and 1.31 +/- 0.67 g kg(-1), respectively. The mean atomic ratio of c:N:P is 37:3:1 in the surface of urban soils that strictly differs from natural soils in china and the whole world. The mean of c:N ratio in urban soils is similar to that of agriculture, grassland, and forest soils. However, the ratios of c:P and N:P in urban soils are much lower than that in agricultural, forest, and grassland soils. This implies that P is extremely enriched in the urban soils. The high c in urban soils are considered coming from natural and anthropogenic sources. The high N and P mainly come from anthropogenic sources. conclusions The well-constrained c:N:P ratio in rural soils does not apply for urban soils. The abnormal c:N:P ratio of urban soils is the r

关键词： Urbanization Ecological environment Stoichiometry c N c P N P

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Structural and biochemical insights into the recognition of RNA helicase cGH-1 by cAR-1 in c. elegans

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BIOcHEMIcAL AND BIOPHYSIcAL RESEARcH cOMMUNIcATIONS 2021年 549卷 135-142页

作者： Zhang, Yong Lv, Mengqi Li, Fudong Li, Meili Zhang, Jiahai Shi, Yunyu Hong, Jingjun Univ Sci & Technol China Hefei Natl Lab Phys Sci Microscale Sch Life Sci Div Life Sci & Med Hefei 230027 Anhui Peoples R China Univ Sci & Technol China Key Lab Membraneless Organelles & Cellular Dynam Minist Educ Hefei Peoples R China

A protein-RNA complex containing the RNA helicase cGH-1 and a germline specific RNA-binding protein cAR-1 is involved in various aspects of function in c. elegans. However, the structural basis for the assembly of this protein complex remains unclear. Here, we elucidate the molecular basis of the recognition of cGH-1 by cAR-1. Additionally, we found that the ATPase activity of cGH-1 is stimulated by NTL1a MIF4G domain in vitro. Furthermore, we determined the structures of the two RecA-like domains of cGH-1 by X-ray crystallography at resolutions of 1.85 and 2.40 ?, respectively. Structural and biochemical approaches revealed a bipartite interface between cGH-1 RecA2 and the FDF-TFG motif of cAR-1. NMR and structure-based mutations in cGH-1 RecA2 or cAR-1 attenuated or disrupted cGH-1 binding to cAR 1, assessed by ITc and GST-pulldown in vitro. These findings provide insights into a conserved mechanism in the recognition of cGH-1 by cAR-1. Together, our data provide the missing physical links in understanding the assembly and function of cGH-1 and cAR-1 in c. elegans. ? 2021 Elsevier Inc. All rights reserved.

关键词： cGH-1 cAR-1 NMR ATPase Structure c elegans

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A small excitation window allows long-duration single-molecule imaging, with reduced background autofluorescence, in c. elegans neurons

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OPTIcS cOMMUNIcATIONS 2023年第1期545卷

作者： Mitra, Aniruddha Loseva, Elizaveta Haasnoot, Guus H. Peterman, Erwin J. G. Vrije Univ Amsterdam Dept Phys & Astron Amsterdam Netherlands Vrije Univ Amsterdam LaserLaB Amsterdam Netherlands

Single-particle imaging using laser-illuminated widefield epi-fluorescence microscopy is a powerful tool to investigate molecular processes in vivo. Performing high-quality single-molecule imaging in such biological systems, however, remains a challenge due to difficulties in controlling the number of fluorescing molecules, photobleaching, and the autofluorescence background. Here, we show that by exciting only a small, 5-15 & mu;m wide region in chemosensory neurons in live c. elegans, we can significantly improve the duration and quality of single-molecule imaging. Small-window illumination microscopy (SWIM) allows long-duration single-particle imaging since fluorescently labelled proteins are only excited upon entering the small excited area, limiting their photobleaching. Remarkably, we also find that using a small excitation window significantly improves the signal-to-background ratio of individual particles. With the help of theoretical calculations, we explain that the improved signal-to-background ratio is due to reduced background, mostly caused by out-of-focus autofluorescence. We demonstrate the potential of this approach by studying the dendritic transport of a ciliary calcium channel protein, OcR-2, in the chemosensory neurons of c. elegans. We reveal that OcR-2-associated vesicles are continuously transported back and forth along the length of the dendrite and can switch between directed and diffusive states. Furthermore, we perform single-particle tracking of OcR-2-associated vesicles to quantitatively characterize the transport dynamics. SWIM can be readily applied to other in vivo systems where intracellular transport or cytoskeletal dynamics occur in elongated protrusions, such as axons, dendrites, cilia, microvilli and extensions of fibroblasts.

关键词： c elegans Fluorescence microscopy Single-molecule Neuronal transport Molecular motors In vivo

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Anti-ablation performance of plasma sprayed ZrB2/Sic coatings on c/c substrates and the influence of a chemical vapor deposited Sic interlayer

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MATERIALS TODAY cOMMUNIcATIONS 2023年 36卷

作者： Gao, Zhi-ting Ma, Zhuang Liu, Qiang Zhang, Ze Wang, Yi-fan Liu, Shao-pu Liu, Ling Liu, Yan-bo Beijing Inst Technol Sch Mat Sci & Engn Beijing 100081 Peoples R China Beijing Inst Technol Chongqing Innovat Ctr Chongqing 401120 Peoples R China Northeastern Univ Sch Mat Shenyang 110819 Peoples R China

To address the industrial usage of carbon/carbon (c/c) substrates with plasma-sprayed ZrB2/Sic coatings, a continuous and dense chemical vapor deposition (cVD)-Sic interlayer of 150 & mu;m was deposited on a c/c sub-strate. The integration of cVD-Sic with the c/c substrate and plasma sprayed (PS) ZrB2/Sic coatings results in a tight interface. The Sic interlayer significantly reducing thermal stress in the optimized composites up to 1828 Mpa, a decrease of approximately 60% compared to standard composites without cVD-Sic. Ablation tests con-ducted showed that the optimized composite displayed remarkable mass ablation rate of -11.7% after ablation for 600 s, with a notable increase of -3.5% even after ablation for 1800 s. After 600 s of ablation, the exposed SiO2 layer is approximately 500 & mu;m in size. After 900 s of ablation, the exposed SiO2 layer is approximately 1500 & mu;m. After 1800 s of ablation, the SiO2 is completely evaporated, exposing the c/c matrix, at which point the coating has failed. The Sic interlayer improve the ablation resistance due to the continuous SiO2 film formed by the self-sealing and O anti-diffusive properties.

关键词： cVD-Sic interlayer Plasma spraying Ablation resistance c c substrate

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