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71.
Additive manufacturing consists in melting metallic powders to produce objects from 3D data, layer upon layer. Its industrial applications range from automotive, biomedical (e.g., prosthetic implants for dentistry and orthopedics), aeronautics and others. This study uses life cycle assessment to evaluate the possible improvement in environmental performance of laser‐based powder bed fusion additive manufacturing systems on prosthetic device production. Environmental impacts due to manufacturing, use, and end of life of the designed solution were assessed. In addition, two powder production technologies, gas atomization (GA) and plasma atomization (PA), were compared in order to establish the most sustainable one. Production via traditional subtractive technologies and the additive manufacturing production were also compared. 3D building was found to have a significant environmental advantage compared to the traditional technology. The powder production process considerably influences on a damage point of view the additive manufacturing process; however, its impact can be mitigated if GA powders are employed.  相似文献   
72.
Natural products are important because of their significant pharmaceutical properties such as antiviral, antimicrobial, and anticancer activity. Recent breakthroughs in DNA sequencing reveal that a great number of cryptic natural product biosynthetic gene clusters are encoded in microbial genomes, for example, those of Streptomyces species. However, it is still challenging to access compounds from these clusters because many source organisms are uncultivable or the genes are silent during laboratory cultivation. To address this challenge, we develop an efficient cell-free platform for the rapid, in vitro total biosynthesis of the nonribosomal peptide valinomycin as a model. We achieve this goal in two ways. First, we used a cell-free protein synthesis (CFPS) system to express the entire valinomycin biosynthetic gene cluster (>19 kb) in a single-pot reaction, giving rise to approximately 37 μg/L of valinomycin after optimization. Second, we coupled CFPS with cell-free metabolic engineering system by mixing two enzyme-enriched cell lysates to perform a two-stage biosynthesis. This strategy improved valinomycin production ~5000-fold to nearly 30 mg/L. We expect that cell-free biosynthetic systems will provide a new avenue to express, discover, and characterize natural product gene clusters of interest in vitro.  相似文献   
73.
Sour rot is a disease complex that causes serious damage in viticulture. The common vinegar fly Drosophila melanogaster (Diptera: Drosophilidae) is associated with sour rot in overripe or otherwise damaged grapes. Drosophila suzukii (Diptera: Drosophilidae) is an invasive species, which is suspected to induce sour rot in previously undamaged grapes due to the flies' ability to infest healthy, undamaged soft fruits with its serrated ovipositor. As a consequence, infection of healthy grapes by D. suzukii may facilitate the colonization by D. melanogaster. We investigated the single and combined effects of D. suzukii and D. melanogaster on sour rot development by measuring volatile acidity under near-natural conditions in the vineyard, along with laboratory experiments under controlled climate. In 2017, the combined field and laboratory experiments suggested that the presence of D. suzukii and D. melanogaster increased the volatile acidity levels at a similar rate. In 2018, the field experiments showed an only marginal increase in sour rot development in treatments with both Drosophila species. Under more favourable laboratory conditions, the presence of D. suzukii, but not D. melanogaster triggered sour rot emergence. A facilitating effect of D. suzukii infestation for D. melanogaster was not detectable. These findings suggest that D. suzukii does in fact have the potential to trigger sour rot, but will probably rarely do so under field conditions in the vineyard, at least in the studied region. Instead, our study showed that D. melanogaster can have a similar impact on sour rot development as D. suzukii, emphasizing the need of comparative studies.  相似文献   
74.
75.
Vibsanin A is the first natural product isolated from Viburnum awabuki and has several biological activities. We have reported that a vibsanin A analog, obtained from process of total synthesis of vibsanin A, has anti-proliferative activity against human cancer cell lines. In this study, we evaluated anti-proliferative effect of the vibsanin A analogs against various human cancer cell lines and examined molecular target of the analog in human cells. Among the vibsanin A analogs, vibsanin A analog C (VAC) showed anti-proliferative effect against various cancer cell lines, and the anti-proliferative activity was strongest among the vibsanin A analogs. Additionally, VAC fluctuated amounts of HSP90-related proteins in cells and inhibited HSP90-mediated protein refolding of luciferase in vitro. These results suggest that the anti-proliferative activity of VAC is due to HSP90 inhibition, and VAC has a potential as novel anti-cancer drug as HSP90 inhibitor.  相似文献   
76.
The migration sources and pathways of Sogatella furcifera (Horváth) in topologically complex regions like Yunnan, China, and adjacent montane areas have long been a challenging task and a bottleneck in effective pest forecast and control. The present research reinvestigated this issue using a combination of mtDNA and long‐term historical wind field data in an attempt to provide new insights. Genetic analyses showed that the 60 populations of S. furcufera collected across Myanmar, Thailand, Laos, Vietnam, Yunnan, Guizhou, and Sichuan lack genetic structure and geographic isolation, while spatial analysis of haplotype and diversity indices discovered geographic relevance between populations. Migration rate analysis combined with high‐resolution 10‐year wind field analysis detected the following migration sources, pathways, and impacted areas which could explain the outbreak pattern in Yunnan. (a) Dominating stepwise northward migrations originated from northern Indochina, southern Yunnan, and central‐eastern Yunnan, impacting their northern areas. (b) Concurring summer–autumn southward (return) migration originated from nearly all latitude belts of Sichuan and Yunnan mainly impacting central and southern Yunnan. (c) Regular eastward and summer–autumn westward migrations across Yunnan. The northward migration reflects the temporal rhythm of gradual outbreaks from the south to the north in a year, while the return migration may explain the repeated or very severe outbreaks in the impacted areas. To form a better pest forecast and control network, attention must also be paid to the northern part of Yunnan to suppress the impact of return migration in summers and autumns.  相似文献   
77.
高源  孙丽丽  曹传旺 《昆虫学报》2021,64(10):1218-1234
昆虫口腔分泌物(oral secretion, OS),又称返吐液,是昆虫唾液腺分泌的唾液和肠道分泌物的混合液。昆虫取食寄主植物过程中,OS随之分泌至植物中,并影响植物的防御反应。RNA干扰(RNAinterference, RNAi)是研究昆虫基因功能有价值的反向遗传学工具,也是目前最有可能应用于害虫防治的新技术。本文主要综述了昆虫OS对寄主植物防御的影响、昆虫OS效应子的鉴定和OS效应子基于RNAi技术在害虫防治中可行性及应用前景。昆虫OS对寄主植物防御的影响主要表现为干扰植物的茉莉酸信号通路、筛管阻塞、Ca2+通路等防御反应,进而促进昆虫摄取食物。目前,昆虫OS效应子主要鉴定手段是通过昆虫唾液腺转录组分析和OS蛋白组分析;而已鉴定的OS效应子主要来源于刺吸式口器昆虫,在咀嚼式口器昆虫中的报道甚少;功能研究发现昆虫OS效应子在寄主植物中的表达会影响昆虫存活率、繁殖力和取食能力及昆虫和植物的其他重要生理指标,并通过鉴定OS效应子与植物防御机制的相互作用关系,进而证明OS效应子在昆虫与寄主植物关系中的重要性。基于RNAi技术,通过注射、饲喂和植物介导RNAi等方法在多种昆虫中产生了OS效应子基因下调和生长发育受影响的现象,由此说明OS效应子基因已具备作为RNAi靶标的条件。虽然目前研究尚处于实验室阶段,但已证明其应用于害虫防治方面具有一定的可行性。昆虫口腔分泌物是研究昆虫与寄主植物相互作用机制的新方向。最后,对OS未来潜在的研究方向进行了展望,以期对我国害虫防治的研究提供理论指导。  相似文献   
78.
Biological pest control by means of beneficial organisms is for long part of agriculture and Integrated Pest Management (IPM). A new and efficient strategy to control the most common timber pest species in churches and museums, the furniture beetle Anobium punctatum (De Geer) (Coleoptera: Anobiidae), is based on the parasitoid wasp species Spathius exarator (Linnaeus) (Hymenoptera: Braconidae). Once this braconid wasp detects its host species beneath the surface, it pierces the wood with its ovipositor to lay one single egg onto the beetle larva. After hatching, the wasp larva feeds on the beetle larva thereby killing it. Afterwards, it pupates and emerges through a self-gnawed hole as an adult wasp. The tiny, 0.5-mm-wide exit hole can easily be distinguished from the 1- to 2-mm-wide exit hole of A. punctatum. Laboratory tests revealed that female wasps have an average life span of 85 days and produce a total of 24 offspring, when nutrition is provided. Between 2012 and 2019, braconid wasps were introduced into 54 different A. punctatum infested buildings. Treatment success was monitored by examining exit holes of new beetles and wasps thereby calculating corresponding parasitism rates. After the first year of treatment, parasitism rates were significantly higher with a mean value of 0.15 when compared to untreated objects with a natural parasitism and a mean value of 0.08 (n = 54). Following treatment of three objects over a period of eight years, parasitism rates continuously increased from 0.02 up to 0.31. In a church organ, which was treated during this period, the monitoring revealed a complete suppression of pest activity. These data prove that this biological method of pest control is an efficient, sustainable and non-toxic option to manage the common furniture beetle.  相似文献   
79.
Contextualizing evolutionary history and identifying genomic features of an insect that might contribute to its pest status is important in developing early detection and control tactics. In order to understand the evolution of pestiferousness, which we define as the accumulation of traits that contribute to an insect population's success in an agroecosystem, we tested the importance of known genomic properties associated with rapid adaptation in the Colorado potato beetle (CPB), Leptinotarsa decemlineata Say. Within the leaf beetle genus Leptinotarsa, only CPB, and a few populations therein, has risen to pest status on cultivated nightshades, Solanum. Using whole genomes from ten closely related Leptinotarsa species native to the United States, we reconstructed a high‐quality species tree and used this phylogenetic framework to assess evolutionary patterns in four genomic features of rapid adaptation: standing genetic variation, gene family expansion and contraction, transposable element abundance and location, and positive selection at protein‐coding genes. Throughout approximately 20 million years of history, Leptinotarsa species show little evidence of gene family turnover and transposable element variation. However, there is a clear pattern of CPB experiencing higher rates of positive selection on protein‐coding genes. We determine that these rates are associated with greater standing genetic variation due to larger effective population size, which supports the theory that the demographic history contributes to rates of protein evolution. Furthermore, we identify a suite of coding genes under positive selection that are putatively associated with pestiferousness in the Colorado potato beetle lineage. They are involved in the biological processes of xenobiotic detoxification, chemosensation and hormone function.  相似文献   
80.
开展生态系统生产总值(GEP)核算是推进生态文明制度建设的必要措施,也是将生态效益纳入经济社会发展评价体系的重要举措。本研究以福州市为研究对象,通过构建具有“山、海、城”特色的生态系统价值核算体系,对2015和2018年福州市GEP进行核算,从时空变化角度对福州市GEP进行对比。结果表明: 2015、2018年福州市GEP分别为9205.92、10472.42亿元,人均GEP分别为13.02、14.39万元,生态产品供给服务价值分别为941.81、1102.61亿元,生态调节服务价值分别为6364.20、5988.51亿元,生态文化服务价值分别为1899.91、3381.3亿元。与2015年相比,2018年福州市GEP增加1266.50亿元,增幅为13.8%,主要得益于生态产品供给服务价值和生态文化服务价值的增加。然而,生态调节服务价值减少375.69亿元,降幅为5.9%,主要源于气候调节、水流动调节和水质净化服务价值的减少。福州率先探索建立一套具有山、海、城特色的核算体系,可以为福建省其他城市及我国其他地区的核算工作提供“福州样板”,同时助推建立生态价值实现的长效机制。  相似文献   
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