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11.
有性生殖在真菌的生活史和进化过程中具有重要作用,而交配型基因是控制有性生殖的关键因子。前期研究发现稻曲病菌(Villosiclava virens)MAT1-2型菌株中包含MAT1-2-1和MAT1-2-8两个交配型基因,但是它们如何调控稻曲病菌有性生殖依然不清楚。本文研究了它们在不同侵染和生长发育时期的表达模式和编码的蛋白结构特性。研究表明MAT1-2-1在侵染不同阶段一直下调表达;而MAT1-2-8在侵染早期(5 dpi)上调表达,在侵染后期下调表达。与营养菌丝阶段比较,MAT1-2-1和MAT1-2-8在有性发育过程菌核形成、菌核萌发、子座原基形成和子座成熟4个阶段的表达量都是下降的,在菌核形成阶段表达量最低。生物信息学分析显示MAT1-2-1和MAT1-2-8具有磷酸化位点,为非分泌蛋白,无明显的跨膜结构域。蛋白同源比对分析表明MAT1-2-1与香柱菌(Epichloë typhina)的MAT1-2-1同源性最高,而MAT1-2-8与绿僵菌(Metarhizium)的MBR_08192蛋白同源性最高。进一步研究发现MAT1-2-1和MAT1-2-8能够互作,并分别主要定位在细胞核和细胞基质中。通过质谱技术鉴定到MAT1-2-1的一些候选互作蛋白,如假定Ran交换因子Prp20/Pim1(KDB12229.1)、假定rRNA处理蛋白Ebp2(KDB12923.1)及组蛋白H1(KDB12711.1)等。因此,以上结果为研究稻曲病菌交配型基因MAT1-2-1和MAT1-2-8调控有性生殖的生物学功能奠定了基础。 相似文献
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为解决雨洪管理模型(SWMM)在率定过程中参数复杂、过程繁琐等问题。以西宁市某地块为例建立SWMM模型,利用Morris筛选法进行参数灵敏度分析,并根据灵敏度分析的结果进行人工率定;另外利用BP神经网络对模型进行率定,并结合参数灵敏度对其进行优化。对3种率定方案进行分析,结果表明:水文水力模块参数的相对灵敏度基本一致,其中灵敏度较大的参数为子汇水区面积(Area)、不透水率(Imperv)和不透水区洼地蓄积量(Destore-Imperv),并且不同降雨条件下模型参数的灵敏度存在差异。经过优化后的BP神经网络参数率定方法的模型模拟效果最好,纳什系数最大。结合灵敏度优化BP神经网络的人机联合率定方法一方面能提高BP神经网络率定的准确性,另一方面又能提高传统人工率定的效率。 相似文献
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Mingzhu HE 《干旱区科学》2020,12(4):701-715
In arid desert regions of northwestern China, reclamation and subsequent irrigated cultivation have become effective ways to prevent desertification, expand arable croplands, and develop sustainable agricultural production. Improvement in soil texture and fertility is crucial to high soil quality and stable crop yield. However, knowledge on the long-term effects of the conversion of desert lands into arable croplands is very limited. To address this problem, we conducted this study in an arid desert region of northwestern China to understand the changes in soil physical-chemical properties after 0, 2, 5, 10, 17, and 24 years of cultivation. Our results showed that silt and clay contents at the 17-year-old sites increased 17.5 and 152.3 folds, respectively, compared with that at the 0-year-old sites. The soil aggregate size fraction and its stability exhibited an exponential growth trend with increasing cultivation ages, but no significant change was found for the proportion of soil macroaggregates (>5.00 mm) during the 17 years of cultivation. The soil organic carbon (SOC) content at the 24-year-old sites was 6.86 g/kg and increased 8.8 folds compared with that at the 0-year-old sites. The total (or available) nitrogen, phosphorus, and potassium contents showed significant increasing trends and reached higher values after 17 (or 24) years of cultivation. Changes in soil physical-chemical properties successively experienced slow, rapid, and stable development stages, but some key properties (such as soil aggregate stability and SOC) were still too low to meet the sustainable agricultural production. The results of this long-term study indicated that reasonable agricultural management, such as expanding no-tillage land area, returning straw to the fields, applying organic fertilizer, reducing chemical fertilizer application, and carrying out soil testing for formula fertilization, is urgently needed in arid desert regions. 相似文献
15.
Equine herpesvirus type 1 (EHV-1) is responsible for respiratory disorders, abortion and myeloencephalopathy (EHM) in horses. Two pathotypes of EHV-1 strains are circulating in the field: neurovirulent (N) and non-neurovirulent (NN). For both strains, CD172a+ monocytic cells are one of the main carrier cells of EHV-1 during primary infection, allowing the virus to invade the horse’s body. Recently, we showed that EHV-1 NN strains showed a restricted and delayed replication in CD172a+ cells. Here we characterize the in vitro replication kinetics of two EHV-1 N strains in CD172a+ cells and investigate if the replication of these strains is similarly silenced as shown for EHV-1 NN strains. We found that EHV-1 N replication was restricted to 7–8% in CD172a+ cells compared to 100% in control RK-13 cells. EHV-1 N replication was not delayed in CD172a+ cells but virus production was significant lower (103.0 TCID50/105 inoculated cells) than in RK-13 cells (108.5 TCID50/105 inoculated cells). Approximately 0.04% of CD172a+ cells produced and transmitted infectious EHV-1 to neighbour cells compared to 65% of RK-13 cells. Unlike what we observed for the NN strain, pretreatment of CD172a+ cells with histone deacetylases inhibitors (HDACi) did not influence the replication of EHV-1 N strains in these cells. Overall, these results show that the EHV-1 replication of N strains in CD172a+ cells differs from that observed for NN strains, which may contribute to their different pathogeneses in vivo. 相似文献
16.
Susanna Price 《Asia Pacific viewpoint》2019,60(2):191-204
The realisation that climate change might necessitate resettlement of people displaced initially raised interest in the experience of development‐forced displacement and resettlement (DFDR). Looking back, in 1980 the first international policy on involuntary resettlement was approved to address perceived weaknesses in state property and expropriation law to safeguard people in the way of development projects. Since then international policy and praxis have brought global attention to developmentally displaced people but have not guaranteed them an effective safeguard. Recently, renewed attention has focussed on state legal and governance frameworks substantively and procedurally. Identifying four key policy objectives that resonate with climate change displacement I analyse their treatment in a data base of DFDR laws and regulations from 40 Asia Pacific states. This analysis finds overall little legal congruence. Innovative new formulations in some Asian state laws address recent public criticisms and research findings, but mostly are yet to demonstrate positive outcomes for displaced people. Pacific states increasingly abandon expropriation law to negotiate lease terms for public infrastructure projects with customary landowners that do not extinguish customary title. Any laws governing climate change relocations must protect rights, livelihoods, well‐being, inclusive decision‐making and community initiatives with procedures whilst not relinquishing climate‐change‐reducing action. 相似文献
17.
Freshwater fishes are threatened globally, and often too little is known about threatened species to effectively guide their conservation. Habitat complexity is linked to fish species diversity and persistence, and degraded streams often lack habitat complexity. Beaver Castor spp., in turn, have been used to restore streams and increase habitat complexity. The northern leatherside chub Lepidomeda copei is a rare, small‐bodied, drift‐feeding minnow that has anecdotally been observed to use complex habitats associated with beaver dams in the western United States. To investigate this anecdote, we conducted fish and habitat surveys, the latter focusing on quantifying habitat complexity, in a sub‐basin of the Upper Snake River Basin in the USA. Complementary generalised linear model and path analyses revealed that northern leatherside chub occurred more often at sites with complex streamflows, and streamflows were more complex when beaver dams were present and pools were deeper. Northern leatherside chubs were also more likely to occur when temperatures were warmer, aquatic macrophytes were abundant and stream channels were narrow and deep. The linkage between chubs, complex streamflows and beaver dams needs to be evaluated more broadly to completely understand its role in the rangewide status of the species. However, it does suggests that increased use of beaver reintroductions and dam analogues for stream restoration could be a boon for the northern leatherside chub, but such efforts should be monitored to determine their effectiveness to help adapt beaver‐based restoration approaches to best benefit the species. 相似文献
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以稻谷为原料,对蒸谷米的复水性进行了研究。通过单因素试验,探讨超高压浸泡工序、蒸煮工序、干燥工序中相关参数的影响规律,并以蒸煮时柠檬酸添加量、蒸煮次数、微波干燥时间为变量,成品复水率为指标,通过响应面分析建立回归方程,得出蒸煮次数对复水性影响最大,柠檬酸添加量次之,干燥时间影响最小。利用模型确定了较佳参数为柠檬酸添加量1.1%,微波干燥时间6.4 min,蒸煮次数3次。 相似文献
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基于农业科技创新的发展需求,为农业科技资源的有效配置提供支撑,从文献计量角度对全球植物科学领域研究现状及态势进行分析。利用定性、定量相结合的方法构建检索策略,基于Web of Science数据库及文献计量分析工具,对文献发表量、文献主要贡献国家、机构、期刊及发文量较高的作者H指数进行统计分析。结果表明,1995—2018年植物科学领域的文章发表量整体上呈现稳定增长趋势,学科呈现蓬勃发展的整体势头。美国和中国是文献主要贡献国家,文献量和总被引频次显著高于其他国家,但美国及欧洲国家的篇均被引数量高于中国。从全球来看,中国科研机构在发文数量占有绝对优势,而德国马克思普朗克的文章篇均被引数量高,达到10以上。对2016—2018年的高被引文献(Top10)进行内容分析,并通过高频词共现主题聚类可视化分析。从论文影响力及主题词规模2个维度表征领域内研究方向。结果表明,“植物应对生物及非生物胁迫”、“基因编辑技术”、“基因组学分析”、“植物生殖发育调控”是近年来植物科学的高关注度研究方向,主题内容与前期的需求调研相符,初步预测这些研究方向将对农业创新发展起到重要推动作用。 相似文献