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1.
用自己编写的siRNA查找设计的程序sRNAFinder,对来自GenBank的7个冠状病毒全基因组序列进行了siRNA的查找,并分析了各自的分布情况。结果表明,ORF1ab、S、E、M和N这5个主要基因中,候选siRNA占全基因组中所有候选siRNA的比例达到90%以上,根据基因组结构特征,对SAILS—CoV进行的siRNA分布分析表明,在全部449个候选siRNA中,有443个分布于orf1ab中,与基于RNAi原理的抗病毒药物设计思想相吻合。表8参15。  相似文献   

2.
为研究山桐子遗传多样性,对山桐子转录组数据进行分析,开发SSR分子标记技术.将山桐子高通量转录组测序获得的84 213条Unigene进行简单重复序列(SSR)位点挖掘和分析,并结合引物验证,初步证明其可行性.通过软件分析,共获得含SSR位点的序列数23 077,出现频率为27.40%,涉及序列数量为29 953条,发生频率为35%.SSR序列中包括1 620种重复基元类型,其中单核苷酸、二核苷酸和三核苷酸为优势重复类型,SSR位点数分别为9 782(32.67%)、6 921(23.11%)和5 420(18.10%).单核苷酸中A/T类型比例最高,为9 630(32.15%),二核苷酸和三核苷酸中以类型AG/CT(4 679;15.62%)和AAG/CCT(1 220;1.53%)为主.SSR位点重复次数差别较大,主要是3次(4 748;15.70%),其次为6次(3 707;12.25%)和5次(3 475;11.60%).运用多态性分析的方式初步验证SSR位点在不同地区山桐子标记中的可行性.同时,利用Primer 5.0进行引物设计,随机筛选100对引物进行验证,31对引物可以扩增出条带,19对引物扩增出预期大小的条带,8对引物能特异性区分宜宾、资阳、宁强、成都4个不同地区的山桐子.本研究通过分析山桐子高通量转录组序列的SSR信息,筛选出8对引物验证不同地区山桐子的遗传多样性,将有助于山桐子基因挖掘、分子标记育种和资源保护等后续工作的开展.  相似文献   

3.
大麦是一种古老的栽培作物,也是分子遗传学研究中常用的模式植物,为满足大麦基因作图、遗传多样性、种质资源鉴定和分子辅助育种等研究的需求,拟在NCBI公共数据库基础上,开发基于表达序列标签(EST)的简单序列重复(SSR)分子标记.从NCBI数据库中获得了525 781条大麦EST序列,将这些序列进行聚类和去冗余后共获得61 902个Unigene,随后通过MISA软件搜索Unigene中的SSR位点,并设计引物9 659对,最后通过电子PCR(E–PCR)和普通PCR对引物进行验证.结果显示:(1)61 902个Unigene中含有SSR位点24 648个,其中复合SSR位点5 843个,约占3.42%,单纯SSR位点23 805个,约占96.58%;(2)经E-PCR验证后发现9 659对SSR引物中有1 060对(11%)能够成功扩增出产物;(3)随机选取的11对引物经普通PCR验证发现,这些引物都能在2份野生大麦品种、2份栽培大麦品种及1份小麦、硬粒小麦、荆州黑麦和节节麦中成功扩增.本研究表明日益丰富的EST公共数据库是大麦SSR分子标记的重要来源;利用EST公共数据库、SSR搜索软件,结合E–PCR验证是开发SSR分子标记省时高效的手段.  相似文献   

4.
硫氧化还原酶(Sulfur oxygenase/reductase,SOR)在嗜热酸古菌硫氧化代谢中具有关键性作用,其催化机理和分子工程等都得到广泛关注.对SOR所涉及的亚基进行分子同源建模研究,并评估其可用性,通过1)序列相似性搜索,2)序列和结构比对,3)初始建模,4)分析和评估,5)精修和优化获得未知三维结构SOR的三维模型.同时讨论了此类蛋白质结构建模、评估策略、特征数据提取等.  相似文献   

5.
把一个新鸡贫血病毒(CAV)的vp1基因通过PCR扩增,然后克隆到质粒载体pUC18上.vp1基因包含1347个碱基对,并且推定的VP1蛋白氨基酸序列含有449个氨基酸.通过DNA BLAST软件把该基因的序列数据与在GenBank中发表的其他vp1基因比较显示,克隆的vp1基因与已发表的其他vp1基因之间存在许多核甘酸差异.核甘酸的变异导致其编码蛋白质的某些氨基酸发生改变.氨基酸的改变主要集中在VP1蛋白的29、75、125、141、144、251、254、447位.在这些变异中,许多氨基酸的电荷和/或疏水性发生了改变,例如:Gly→Glu、Val→Glu、Ala→Thr、Leu→Gln、Cys→Trp、Leu→Arg、Arg→Ala、Gly→Ser、Ser→Ala、Glu→Gly、Gly→Thr等.通过CLUSTAL X软件比较了6个不同的vp1基因.该vp1基因已被GenBank登录(登录编号:AF448446).VP1蛋白是CAV的唯一衣壳蛋白,因此VP1的氨基酸变异可能影响该蛋白质的抗原特征.对该vp1基因进一步进行免疫学研究具有重要意义,并且有可能应用该基因构建CAV基因工程疫苗.图1表3参20  相似文献   

6.
以15种包括同质异核和同核异质高粱材料的总:DNA为模板进行RAPD分析,196个随机引物中,引物Y-19扩增得到一个很有规律的差异片段SAY-192300。该片段只出现在4个保持系(B)和3个恢复系(R)中,而不出现在6个不育系(A)和2个杂种F1中,进一步对cms—Al、cms—A2两套8个材料(A/B/R/F1)的总DNA、mtDNA和cpDNA用引物Y-19进行扩增,发现片段SAY-192300仅在cpDNA得到,Southern杂交结果证实了片段SAY-192300的叶绿体来源,同时也表明在cms胞质中该片段所在区未发生插入、缺失等大的结构变异,DNA序列测定结果表明,该片段为叶绿体ps1A1和ps1A2基因的部分序列。图6表2参19。  相似文献   

7.
筛选并鉴定了1株高产脂肪酶菌株葡枝根霉YF6,并采用简并PCR等分子技术从中克隆到1个新的脂肪酶基因lipRs及其对应的全长cDNA,序列分析表明,该基因编码区全长1173bp,不含内含子序列,编码1段由26个氨基酸残基组成的信号肽和1个由365个氨基酸残基组成的成熟蛋白,该成熟蛋白计算分子量(Mr)为39268.27,等电点为pH7.66,有5个可能的N-糖基化位点,含有脂肪酶特征序列GHSLGGA,与来自米根霉(Rhizopus oryzae)的脂肪酶(AAF32408)同源性最高,一致性为83%,相似性为89%.该基因序列已提交GenBank,登录号为DQ139862.  相似文献   

8.
链格孢菌菌株致病性及其遗传差异性   总被引:6,自引:1,他引:6  
对分离自紫茎泽兰的19个链格孢菌菌株的致病性进行了比较研究,并对这19个菌株和其它来源的3个菌株的5.8S rDNA及其两侧的ITS1区和ITS2区进行了序列分析.结果显示,链格孢菌菌株的致病性差异明显;21株链格孢菌菌株在5.8SrDNA及其两侧的转录问区(ITS区)的序列无差异,而与百日草链格孢菌(Alternaria zinnine)的序列差异显著,表明21株链格孢菌菌株属种内变异.采用AFLP分子标记技术对21株链格孢菌的DNA扩增片段长度多态性进行了分析,结果表明,链格孢菌自然变异群体内存在很高的遗传多样性.链格孢菌菌株的相似性与菌株的地理来源有一定的相关性,但基于AFLP标记划分的AFLP类群与基于寄主病情指数划分的致病力类群问关系不相一致;起始菌株与变异菌株相似性显著,但二者和致病性的关系不显著.图2表1参18  相似文献   

9.
糯稻和非糯稻蜡质基因的新STS分子标记   总被引:3,自引:0,他引:3  
通过对前人公布的糯性水稻蜡质基因全序列测定结果的分析,根据糯性水稻与非糯性水稻蜡质基因序列位点的差异,设计了两个基于PCR扩增反应的可特异识别糯性水稻的显性和共显性STS分子标记;同时在前人公布的非糯性水稻蜡质基因的不同类型(Wxa和Wxb)的全序列比对分析的基础上,选取了两种基因型特定的差异位点,设计了两个基于PCR扩增反应用于特异识别这两种Wx基因的显性STS分子标记,并用新建立的标记对相应的水稻基因型进行了检测.图2表2参10  相似文献   

10.
4种不同生境的蟹类金属硫蛋白cDNA的克隆与比较   总被引:2,自引:0,他引:2  
利用Carcinus maenas金属硫蛋白氨基酸序列资料,用全简并引物从鳃组织总RNA中扩增并克隆了首个甲壳类金属硫蛋白cDNA片段序列,3'-RACE获得了其编码区全长cDNA。之后,用部分简并的引物扩增并克隆了其它3种国内常见蟹类的金属硫蛋白cDNA编码区全长序列。序列分析结果表明,几种蟹的金属硫蛋白cDNA序列存在差异,推知的氨基酸序列也不完全相同,比较不同蟹的cDNA和氨基酸序列数据不能证明不同生态环境对金属硫蛋白的分子进化起重要作用。图4表1参15  相似文献   

11.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

12.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

13.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

14.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

15.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

16.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

17.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

18.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

19.
How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.  相似文献   

20.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

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