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排序方式: 共有2219条查询结果,搜索用时 15 毫秒
1.
Zhi Zheng Shang Gao Meixue Zhou Guijun Yan Chunji Liu 《Molecular breeding : new strategies in plant improvement》2017,37(9):107
Fusarium crown rot (FCR) has become one of the most damaging cereal diseases in semi-arid regions worldwide. Targeting three large-effect QTL (located on the chromosome arm 3BL, 5DS and 2DL, respectively), we investigated the feasibility of enhancing FCR resistance by gene pyramiding. Significant effects were detected for each of the three QTL in both populations assessed. Lines with any combination of two resistant alleles gave significantly better resistance than those with a single resistant allele only and those without any allele, and lines possessing all three resistant alleles showed the best resistance. These results demonstrated that gene pyramiding can be an effective approach in improving FCR resistance. Those lines with resistant alleles from all three QTL could be valuable genetic stocks for breeding programs. 相似文献
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To clarify the mechanisms of Nosema ceranae parasitism, we deep-sequenced both honey bee host and parasite mRNAs throughout a complete 6-day infection cycle. By time-series analysis, 1122 parasite genes were significantly differently expressed during the reproduction cycle, clustering into 4 expression patterns. We found reactive mitochondrial oxygen species modulator 1 of the host to be significantly down regulated during the entire infection period. Our data support the hypothesis that apoptosis of honey bee cells was suppressed during infection. We further analyzed genome-wide genetic diversity of this parasite by comparing samples collected from the same site in 2007 and 2013. The number of SNP positions per gene and the proportion of non-synonymous substitutions per gene were significantly reduced over this time period, suggesting purifying selection on the parasite genome and supporting the hypothesis that a subset of N. ceranae strains might be dominating infection. 相似文献
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Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 µg kg−1 and 0.96 µg L−1 for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (µg kg−1) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg L−1). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P = 0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P = 0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms. 相似文献
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Abstract The potentiation of the biological effects of recombinant porcine growth hormone (pGH) by immunologic manipulation was investigated. A monoclonal antibody (mAb), designated PS‐7.6, was raised against pGH and repeatedly shown to enhance the responsiveness of hypophysectomized (hypox) rats to pGH. As a result, animals receiving a combination treatment of pGH and mAb PS‐7.6 together gained significantly more weight than those receiving the same doses of pGH alone. The enhancing action of the mAb was a rapid process and its effective doses ranged from 0.1 to 2 mg/injection. The ability of the antibody to augment the hormonal activity persisted beyond the 5‐day treatment period and the differences in net weight gain between treated and control animals remained significant for 28 days. Results from treatment frequency studies further suggested that pGH when complexed with mAb PS‐7.6 required fewer injections and produced a greater efficacy than being administered alone. Therefore, present findings suggest that mAb PS‐7.6 may prove useful for not only improving the efficiency of pGH, but also developing a novel formulation for sustained pGH release. 相似文献
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Jian‐Yong Guo Yong‐Sheng Wang Tian Chen Xiao‐Xu Jiang Ping Wu Tao Geng Zhong‐Hua Pan Meng‐Ke Shang Cheng‐Xiang Hou Kun Gao Xi‐Jie Guo 《Insect Science》2020,27(3):449-462
Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) is a major pathogen of the economic insect silkworm, Bombyx mori. Virus‐encoded microRNAs (miRNAs) have been proven to play important roles in host–pathogen interactions. In this study we identified a BmCPV‐derived miRNA‐like 21 nt small RNA, BmCPV‐miR‐1, from the small RNA deep sequencing of BmCPV‐infected silkworm larvae by stem‐loop quantitative real‐time PCR (qPCR) and investigated its functions with qPCR and lentiviral expression systems. Bombyx mori inhibitor of apoptosis protein (BmIAP) gene was predicted by both target prediction software miRanda and Targetscan to be one of its target genes with a binding site for BmCPV‐miR‐1 at the 5′ untranslated region. It was found that the expression of BmCPV‐miR‐1 and its target gene BmIAP were both up‐regulated in BmCPV‐infected larvae. At the same time, it was confirmed that BmCPV‐miR‐1 could up‐regulate the expression of BmIAP gene in HEK293T cells with lentiviral expression systems and in BmN cells by transfecting mimics. Furthermore, BmCPV‐miR‐1 mimics could up‐regulate the expression level of BmIAP gene in midgut and fat body in the silkworm. In the midgut of BmCPV‐infected larvae, BmCPV‐miR‐1 mimics could be further up‐regulated and inhibitors could lower the virus‐mediated expression of BmIAP gene. With the viral genomic RNA segments S1 and S10 as indicators, BmCPV‐miR‐1 mimics could up‐regulate and inhibitors down‐regulate their replication in the infected silkworm. These results implied that BmCPV‐miR‐1 could inhibit cell apoptosis in the infected silkworm through up‐regulating BmIAP expression, providing the virus with a better cell circumstance for its replication. 相似文献
7.
用海建设项目海洋生态损失补偿评估方法及应用 总被引:1,自引:0,他引:1
海洋生态补偿是一种防止海洋生态破坏、增强和促进海洋生态系统良性发展的环境政策,是用海者履行海洋资源有偿使用责任,对因开发利用海洋资源造成的海洋生态价值损失进行的货币化补偿。基于快速化、定量化和差别化补偿评估原则,编制了山东近海海域生态价值基准值表、生态损害系数表以及补偿系数表,建立了一种新的用海建设项目海洋生态损失补偿评估方法体系,包括占用海域和邻近影响海域的海洋生物资源和海洋生态系统服务两个方面的海洋生态价值损失补偿评估。针对2016年山东省5个典型用海项目,核算了其需要缴纳的海洋生态补偿资金,并与旧标准《山东省海洋生态损害赔偿和损失补偿评估方法》(DB37/T 1448—2009)的评估结果进行了对比。结果表明,按照本评估方法,用海企业需要缴纳的生态补偿资金会不同程度地提高,这将有利于用海企业增强资源有偿使用意识,引导企业理性用海,市场经济条件下这有利于海洋资源的优化配置,提高用海效率;另外,按照产业政策不同、受影响海域的生态脆弱性不同对用海建设项目造成的海洋生态损失进行差别化补偿,使得海洋生态补偿标准的评估结果更加科学合理。目前,该方法已经应用于山东海域7个沿海地市9个海区的海洋生态损失补偿评估中,被新发布的山东省地方标准《用海建设项目海洋生态损失补偿评估技术导则》(DB37/T 1448—2015)吸收采用。该评估方法可为海洋管理部门的生态资本核算、生态补偿核算、环评审批和发放许可证提供科学基础,对我国海洋生态环境保护和海洋经济绿色发展以及生态补偿制度实施具有积极推动作用。 相似文献
8.
Ling Wang Yu Wang Yiguang Tian Jinling Shang Xiaoou Sun Hongzhuan Chen Hao Wang Wen Tan 《Bioorganic & medicinal chemistry》2017,25(1):360-371
A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC50 to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer’s disease (AD) treatment. 相似文献
9.
Xiaochun Li Xiangxiang Fu Xulan Shang Wanxia Yang Shengzuo Fang 《Tree Genetics & Genomes》2017,13(4):80
Cyclocarya paliurus, a Chinese monotypic genus belonging to the Juglandaceae, exhibits a widespread distribution in southern China. To provide resource support for its future breeding and medicinal utilization, much information involving natural population succession and genetic diversity of C. paliurus should be obtained. In this study, the structures of 30 natural populations throughout its distribution were analyzed based on the investigation, showing the ratio of individuals with DBH < 40 cm accounting for 71.7%. Inter-simple sequence repeat (ISSR) and simple sequence repeat (SSR) were used for evaluation of 244 individuals from 29 natural populations. High-level polymorphism (100%) indicates high efficiency of two markers. Analysis demonstrated that genetic diversity (value of 0.18 for ISSR and 0.09 for SSR) was low among populations. While gene flow among populations reached 1.182 and 1.335 for ISSR and SSR, respectively, indicating genetic variations mainly existing within population. Twenty-six populations (size ≥5 individuals) were grouped into five clusters based on the combined ISSR and SSR loci. The value of Nei’s coefficient varying from 0.87 to 0.96 indicates small differentiation among groups. Furthermore, we speculate that C. paliurus is an expanding species in subtropical China (most of populations are increasing type (IP)) and discuss the strategy of germplasm conservation. 相似文献
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