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991.
Aude Zingraff‐Hamed Sabine Greulich Stephan Pauleit Karl M. Wantzen 《Restoration Ecology》2017,25(6):994-1004
River restoration (RR) is widely practiced in both rural and urban contexts by combining various goals and measures. The theoretical discourse on RR not yet adequately reflects this breadth of restoration practice. In this study, we investigated 110 French RR projects implemented between 1980 and 2015. We analyzed projects considering eight key design features, main project motivation, restoration goals, project dates, costs, size, funding, river annual discharge, and implemented evaluation procedures. The study (1) provides a detailed account of the French RR effort, (2) compares restoration efforts in urban and rural contexts, and (3) establishes a RR project typology. The results also show that urban RR comprises a wider range of goals and measures than its rural counterpart, includes restoration of riparian habitats, and integrates ecological and social goals. A hierarchical multiple factor analysis yielded five types of projects, Fish RR (14% of the urban and 53% of the rural projects), Blue RR (4%, 7%), Water Framework Directive RR (36%, 40%), Flood protection RR (14%, 0%), and Human RR (32%, 0%). We suggest that the restoration community needs databases that use a project typology as developed in this study. This approach would take into account the multiple facets of RR projects, enabling more transparency into their communication and allow more suitable project comparisons. 相似文献
992.
993.
Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2‐year comparative analysis of field‐grown lines modified for target gene or genetic element expression
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Alexandru Dumitrache Jace Natzke Miguel Rodriguez Jr Kelsey L. Yee Olivia A. Thompson Charleson R. Poovaiah Hui Shen Mitra Mazarei Holly L. Baxter Chunxiang Fu Zeng‐Yu Wang Ajaya K. Biswal Guifen Li Avinash C. Srivastava Yuhong Tang Charles Neal Stewart Jr Richard A. Dixon Richard S. Nelson Debra Mohnen Jonathan Mielenz Steven D. Brown Brian H. Davison 《Plant biotechnology journal》2017,15(6):688-697
Transgenic Panicum virgatum L. silencing (KD) or overexpressing (OE) specific genes or a small RNA (GAUT4‐KD, miRNA156‐OE, MYB4‐OE, COMT‐KD and FPGS‐KD) was grown in the field and aerial tissue analysed for biofuel production traits. Clones representing independent transgenic lines were established and senesced tissue was sampled after year 1 and 2 growth cycles. Biomass was analysed for wall sugars, recalcitrance to enzymatic digestibility and biofuel production using separate hydrolysis and fermentation. No correlation was found between plant carbohydrate content and biofuel production pointing to overriding structural and compositional elements that influence recalcitrance. Biomass yields were greater for all lines in the second year as plants establish in the field and standard amounts of biomass analysed from each line had more glucan, xylan and less ethanol (g/g basis) in the second‐ versus the first‐year samples, pointing to a broad increase in tissue recalcitrance after regrowth from the perennial root. However, biomass from second‐year growth of transgenics targeted for wall modification, GAUT4‐KD, MYB4‐OE, COMT‐KD and FPGS‐KD, had increased carbohydrate and ethanol yields (up to 12% and 21%, respectively) compared with control samples. The parental plant lines were found to have a significant impact on recalcitrance which can be exploited in future strategies. This summarizes progress towards generating next‐generation bio‐feedstocks with improved properties for microbial and enzymatic deconstruction, while providing a comprehensive quantitative analysis for the bioconversion of multiple plant lines in five transgenic strategies. 相似文献
994.
Huan-Lei Zhang Jian-Jun Jin Michael J. Moore Ting-Shuang Yi De-Zhu Li 《Plant Diversity》2018,40(3):127-137
Cannabaceae is an economically important family that includes ten genera and ca.117 accepted species. To explore the structure and size variation of their plastomes,we sequenced ten plastomes representing all ten genera of Cannabaceae.Each plastome possessed the typical angiosperm quadripartite structure and contained a total of 128 genes.The Inverted Repeat (IR) regions in five plastomes had experienced small expansions (330-983 bp) into the Large Single-Copy (LSC) region.The plastome of Chaetachme aristata has experienced a 942-bp IR contraction and lost rpl22 and rps19 in its IRs.The substitution rates of rps19 and rpl22 decreased after they shifted from the LSC to IR.A 270-bp inversion was detected in the Parasponia rugosa plastome,which might have been mediated by 18-bp inverted repeats.Repeat sequences,simple sequence repeats,and nucleotide substitution rates varied among these plastomes. Molecular markers with more than 13% variable sites and 5% parsimony-informative sites were identified,which may be useful for further phylogenetic analysis and species identification.Our results show strong support for a sister relationship between Gironniera and Lozanell (BS=100).Celtis,Cannabis-Humulus,Chaetachme-Pteroceltis,and Trema-Parasponia formed a strongly supported clade,and their relationships were well resolved with strong support (BS=100).The availability of these ten plastomes provides valuable genetic information for accurately identifying species,clarifying taxonomy and reconstructing the intergeneric phylogeny of Cannabaceae. 相似文献
995.
Based on bitter taste receptor T2R2 gene sequence of domesticated dog(AB249685), one pair of primers were designed and used to amplify an approximately 1.1 kb DNA fragment from genomic DNA sample of giant panda by using PCR. The PCR products were ligated into the pMD-18T vector, and then transformed into competent cells of E.coli DH5α. The identified positive clone was sequenced. The result showed that the T2R2 gene of giant panda was 1 008 bp in length, and contained complete exon, and 915 bp, encoding 304... 相似文献
996.
我国部分地区H9亚型禽流感病毒血凝素基因序列比较与遗传发生关系分析 总被引:23,自引:3,他引:20
为从分子水平掌握我国H9亚型AIV的遗传变异情况和流行规律,本研究汇集近年来从我国12个省、市、自治区的发病鸡群中分离到的23株H9亚型禽流感病毒,通过RT-PCR方法和核苷酸序列测定获得了23个毒株的HA基因cDNA核苷酸序列。核苷酸和推导的氨基酸序列同源性比较结果表明,这些毒株HA基因的核苷酸序列同源性为94.1%~100%,氨基酸序列同源性为95.4%~100%;将这23个毒株和来自亚洲及世界其它地区的另外31株的HA基因cDNA序列同源性进行比较发现,分离自香港的HK170499株与日本的2个毒株关系较近;氨基酸序列分析发现,CKGS199、CKTJ196、CKTJ296、CKSH300和CKBJ197五个毒株各发生了一个潜在的糖基化位点的丢失。54株H9亚型AIVHA基因55bp~1152bp的氨基酸序列分析发现,裂解位点尽管有10种基序,但本研究中的23株和近年来从我国大陆和香港地区的分离的毒株则均为RSSR↓GLF;构成受体结合位点的191位氨基酸有一个规律,即所有中国大陆毒株与部分香港毒株都为N,其它毒株均为H,141aa~143aa处的糖基化位点有与191aa类似的规律,即:凡是191aa为N的毒株,该处均为NVS(CKBJ194除外),凡是191aa为H的毒株,则该处均为NVT;遗传发生关系分析,中国大陆毒株处于欧亚谱系的第一支。本研究结果表明近年来我国鸡群中H9N2亚型禽流感病毒的感染流行可能有一个共同的来源,这为制定防治该亚型禽流感流行的有效对策提供了重要的科学依据。 相似文献
997.
真养产碱杆菌112R4酰亚胺酶基因的克隆、序列分析及其在大肠杆菌中的表达 总被引:5,自引:1,他引:4
筛选到一株具海因水解活力的微生物,经鉴定后命名为真养产碱杆菌112R4。该菌能水解海因、二氢尿嘧啶和琥珀酰亚胺,且对琥珀酰亚胺活力最高,但不水解5单取代海因和5,5’双取代海因,因而被确定为含有酰亚胺酶。真养产碱杆菌112R4能在以琥珀酰亚胺为唯一碳、氮源的培养基上生长,表明该菌中存在琥珀酰亚胺完整的转化途径。从112R4基因组DNA出发,用鸟枪法克隆了一个6kb的与环酰亚胺水解相关的DNA片段;进一步亚克隆得到了带酰亚胺酶基因的2kb的DNA片段,并进行了序列测定。缺失分析确定了一个876bp的ORF为真养产碱杆菌112R4的酰亚胺酶基因,推测编码一个291个氨基酸的多肽,这是第一次报道微生物酰亚胺酶的核酸和蛋白序列。推测的氨基酸序列在蛋白数据库中进行了比较,结果表明,酰亚胺酶与已知的环酰胺酶没有明显的同源性,也不属于氨酰水解酶蛋白超家族,因而被分类为一种新的环酰胺酶。真养产碱杆菌112R4的酰亚胺酶与芽生杆菌A17p4的酰亚胺酶N端的20个氨基酸有较高的同源性,一致性为60%,与多糖脱乙酰酶保守序列也部分同源,一致性为14%。带有酰亚胺酶基因的重组质粒在大肠杆菌中得到表达,在lac启动子控制下,使用1mmol/L IPTG诱导5h,酰亚胺酶活力达到3200U/L,为供体菌真养产碱杆菌112R4的7倍。 相似文献
998.
Multiple diverse ligands binding at a single protein site: A matter of pre-existing populations 总被引:10,自引:0,他引:10
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Buyong Ma Maxim Shatsky Haim J. Wolfson Ruth Nussinov 《Protein science : a publication of the Protein Society》2002,11(2):184-197
Here, we comment on the steadily increasing body of data showing that proteins with specificity actually bind ligands of diverse shapes, sizes, and composition. Such a phenomenon is not surprising when one considers that binding is a dynamic process with populations in equilibrium and that the shape of the binding site is strongly influenced by the molecular partner. It derives implicitly from the concept of populations. All proteins, specific and nonspecific, exist in ensembles of substates. If the library of ligands in solution is large enough, favorably matching ligands with altered shapes and sizes can be expected to bind, with a redistribution of the protein populations. Point mutations at spatially distant sites may exert large conformational rearrangements and hinge effects, consistent with mutations away from the binding site leading to population shifts and (cross-)drug resistance. A similar effect is observed in protein superfamilies, in which different sequences with similar topologies display similar large-scale dynamic motions. The hinges are frequently at analogous sites, yet with different substrate specificity. Similar topologies yield similar conformational isomers, although with different distributions of population times, owing to the change in the conditions, that is, the change in the sequences. In turn, different distributions relate to binding of different sizes and shapes. Hence, the binding site shape and size are defined by the ligand. They are not independent entities of fixed proportions and cannot be analyzed independently of the binding partner. Such a proposition derives from viewing proteins as dynamic distributions, presenting to the incoming ligands a range of binding site shapes. It illustrates how presumably specific binding molecules can bind multiple ligands. In terms of drug design, the ability of a single receptor to recognize many dissimilar ligands shows the need to consider more diverse molecules. It provides a rationale for higher affinity inhibitors that are not derived from substrates at their transition states and indicates flexible docking schemes. 相似文献
999.
同一山洞中五种蝙蝠的回声定位比较及生态位的分化 总被引:5,自引:1,他引:4
对同一山洞中5种蝙蝠的回声定位叫声和外部形态作了比较分析,根据蝙蝠回声定位叫声,形态特征与捕食策略之间的联系,并结合部分的野外观察研究,推断其捕食生境及捕食策略,并对洞中5种共栖蝙蝠的生态位分化进行了分析;研究结果如下:(1)南蝠(Ia io)在地面或树冠中间的开阔空间捕食个体较大的昆虫;(2)大鼠耳蝠(Myotis myotis)主要以掠食性方式(gleaning) 捕食森林或草地地表面的昆虫;(3)黄大蹄幅(Hipposideros pratti)主要在树冠周围或树冠上方进行捕蝇器式(Fly-catching)(即倒挂于一固定枝条或地点,探索周围飞行或接近的昆虫,探索到后捕捉回原倒挂地点再进食)或飞行捕食,它主要捕食个体较大的甲虫;(4)角菊头蝠(Rhinolophus cornutus)主要在较密集树木中(枝叶间),农田及树木周围捕食型较小的翼拍动昆虫;(5)三叶蹄幅(Aselliscus wheeleri)是在树木,灌丛或在其周围空间内捕食较小的翼拍动昆虫,但其食性可能菊头蝠不同,根据以上研究结果,认为这5种蝙蝠的取食生态位存在着明显的分化。 相似文献
1000.