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1.
中药青蒿鲨烯合酶的大肠杆菌表达、纯化与功能鉴定   总被引:3,自引:0,他引:3  
利用PCR方法,将经RACE方法克隆到的中药青蒿鲨烯合酶cDNA(AF302464)开放阅读框的3′末端截短99bp,插入到原核表达载体pET30a( )的NcoⅠ和BamHⅠ酶切位点之间,构建N端和C端均携带有HIS6表达标签的鲨烯合酶重组表达载体pETSSA.将pETSSA转入大肠杆菌BL21(DE3),0.5mmol/LIPTG(isopropyl-beta-D-thiogalactoside)28℃诱导重组鲨烯合酶的表达.表达产物经镍琼脂糖柱纯化.纯化蛋白加入酶促反应体系(含FPP和NADPH),GC-MS分析酶促反应体系的正己烷萃取物,结果显示重组鲨烯合酶可以催化FPP向鲨烯的转化.青蒿鲨烯合酶的功能鉴定为进一步利用反义或RNAi技术限制甾类生物合成,从而提高青蒿中的青蒿素含量提供了基础.图5参15  相似文献   

2.
从嗜热子囊菌光孢变种(Thermoascus aurantiacus var.levisporus)RNA中通过RT-PCR克隆出β-葡萄糖苷酶基因bgl Ⅰ的全长序列,cDNA序列为2 672 bp.Genbank登录号为EU269025,将该片段插入巴斯德毕赤酵母Pichia pastoris分泌型表达载体pPIC9K中,获得重组质粒pPIC9K/bgl,经线性化后用电穿孔法导入毕赤酵母GS115中,在醇氧化酶AOXI基因启动子作用下,获得高效表达β-葡萄糖苷酶的毕赤酵母工程菌株.经DEAE-Sepharose Fast Flow阴离子层析纯化了该重组表达蛋白.SDS-PAGER测得该重组蛋白相对分子质量(M)约为120×103.经甲醇诱导,培养基中β-葡萄糖苷酶的活力可达1.2 U/mg,小规模发酵量达0.45 mg/mL.该酶的最适反应温度为60℃,最适反应pH为5.0.于70℃保温30 min仍保持80%的酶活力,具有较高的热稳定性,在pH 3.0~9.0的条件下酸碱耐受性强.图6表1参22  相似文献   

3.
利用纤维二糖的酵母工程菌构建   总被引:4,自引:0,他引:4  
以扣囊复膜孢酵母染色体DNA为模板,通过PCR方法扩增到其β-葡萄糖苷酶基因bgl1,经EcoRⅠ、BamHⅠ双酶切并和经相同酶切的穿梭表达载体pYX212连接,构建了重组质粒pYX-sbgl,转化酿酒酵母W 303-1A,bgl1基因获得了活性表达,β-葡萄糖苷酶活力为0.504 IU/mL.转化子能以纤维二糖为唯一碳源生长,并能应用于同时糖化和发酵纤维素底物生产乙醇,使乙醇产量较宿主酵母有了一定的提高.图6表1参14  相似文献   

4.
甲基对硫磷降解菌GFP标记菌株的构建   总被引:4,自引:1,他引:4  
用Sau3AⅠ酶切甲基对硫磷降解菌DLL 1总DNA ,与BamHⅠ酶切的启动子探针载体 pRobe -GFP酶连 ,转化E .coliDH5α ,在选择性平板LB(Ampr)上从大约 1× 10 4个菌落筛选到 5 0个含启动子片断的阳性克隆 .挑选其中一个阳性克隆 ,将启动子片断克隆到pIJ2 92 5和 pBBR -MCS2上构建成重组质粒 pIJGFP和广宿主标记载体pB BRGFP .然后将 pIJGFP载体上的启动子片断克隆到广宿主载体 pTR10 2上 ,获得第二个广宿主标记载体pTRGFP .将pTRGFP和pBBRGFP通过三亲接合分别标记于DLL 1得到两株标记菌 ,即DLLTR和DLLBR .通过激光共聚焦显微镜观察和软件Lasersharpversion 3.2分析发现 pTRGFP在E .coli中表达很强而在DLL 1中表达很弱 ,而 pBBRGFP正好相反 .图 5表 2参 12  相似文献   

5.
用单个特异引物和通用引物oligo(dT)15从桃受伤叶片cDNA中扩增出1.3kb左右大小的片段.将该扩增产物克隆并对重组克隆作酶切分析发现至少可分为3类.用桃ACC氧化酶基因组DNA为探针进行点杂交表明,4,7,9,10,11,12重组质粒能与之杂交,其中7,9,10,11,12号重组质粒酶切图谱与已报导的桃果实成熟相关的ACC氧化酶cDNA基因基本一致,而4号克隆则不同.DNA序列分析和PCR鉴定表明,插入片段均由5′端特异引物单个引物扩增出来,对7号重组克隆插入片段DNA全序列分析表明,7号重组克隆插入片段全长1146bp,包含了除启始密码子外的全部编码区和192bp的3′端非编码区.通过补上起始密码子ATG构建重组表达载体,在大肠杆菌中表达出35×103的非融合蛋白  相似文献   

6.
将从自杀性重组质粒pDB30上分离的3.6kb含卡那霉素抗性基因和发光酶基因(luxAB)的BglⅡ酶切片段,克隆到小Mr的高拷贝质粒pIJ2925上,构成新的质粒,pHNLX1011;然后将pHNLX1011经BglⅡ部分酶切,酶连在含蔗糖酶基因(sacB)的自杀性重组质粒载体pMH1701上,载体分别采用BglⅡ酶切和BamHⅠ酶切.连接转化后共得到4种重组质粒类型的菌株,它们具有不同发光活性;将它们分别与快生型大豆根瘤菌HN01进行三亲本杂交,发现它们的转座频率均较pDB30高.对经转座标记后的根瘤菌进行发光活性检测,只有pHNC3质粒所转座的根瘤菌浇具有较强发光活性.所得发光根瘤菌衍生菌株能在野大豆和栽培大豆黑农39根际形成正常根瘤,能用X光片记录下根瘤的发光活性.  相似文献   

7.
嗜热子囊菌是一种嗜热真菌,可以产生具有很高工业价值的内切葡聚糖酶.本研究成功表达了嗜热子囊菌内切葡聚糖酶Ⅰ基凶,并获得热稳定的重组内切葡聚糖酶.提取嗜热子囊菌光孢变种(Thermoascus aurantiacus var.levisporus)总RNA,通过RT-PCR方法克隆出内切-β-葡聚糖酶eg1基因的成熟肽编码序列.采用基因重组的方法构建该基因的巴斯德毕赤酵母Pichia pastoris分泌型表达载体pPIC9K-eg1,经线性化后采用电穿孔法将其导入毕赤酵母GS115中,大量筛选后获得高效表达内切葡聚糖酶Ⅰ的毕赤酵母工程菌株GpN24.该菌株采用甲醇诱导120 h后,内切葡聚糖酶Ⅰ的活力可达570.7 U/mL,最适温度为55℃,在90℃的条件下保温30 min后仍具有60%的酶活力;最适pH为5.0,在pH 3.0~5.0的条件下酶活力保持稳定.图6表2参16  相似文献   

8.
为构建携带冷诱导RNA结合蛋白(Cold inducible RNA-binding protein,CIRP)的过表达载体,首先从4℃条件下冷处理8 h的SD大鼠睾丸组织中获得CIRP基因的c DNA序列,然后扩增CIRP基因的编码区,将其克隆到真核表达载体p Lenti6/V5中,酶切鉴定并测序.将克隆成功的质粒转染HEK293T细胞,用Western blot检测CIRP的表达水平.成功扩增CIRP编码区,并将其克隆至载体p Lenti6/V5中;当将CIRP过表达载体转染HEK293T细胞后,Western blot检测结果显示CIRP蛋白表达水平明显增加(P<0.01).本研究成功构建了CIRP过表达载体,为进一步研究CIRP的作用机制提供了基础工具.  相似文献   

9.
利用PCR技术扩增了粉纹夜蛾(Trichoplusia ni)颗粒体病毒增效基因全长片段,扩增产物用EcoRⅠ/HindⅢ双酶消化,经0.7%低熔点琼脂糖凝胶电泳纯化后插入pRSET-B中,得重组表达质粒pRSET/enhancin;但重组子生长异常,在IPTG诱导下未能明显表达目标蛋白.用PstⅠ/HindⅢ双酶消化pRSET/enhancin,电泳回收2.7kb片段后插入pQE-30中,得重组表达载体pQE/enhancin;在IPTG诱导下于35℃成功表达出分子量(Mr)约为108×103的融合蛋白并命名为P108.初步纯化的P108显示了极显著的增效活性,对棉铃虫核型多角体病毒感染棉铃虫3龄幼虫的7d致死率提高34.03%,LT50缩短1.4d;对苏云金杆菌杀棉铃虫3龄幼虫的72h致死率提高65.96%.图4表2参14  相似文献   

10.
根据烟草(Nicotiana tabacum)GA 20-氧化酶基因序列,设计2对分别含有特定酶切位点的特异引物,以烟草基因组DNA为模板,扩增目的基因(约250 bp)片段.将正、反向目的片段分别插入中间载体的内含子两侧.再经BamH I和Sac I双酶切回收约700 bp的目的片段,插入到双元载体质粒p2355中,成功构建了含GA 20-氧化酶基因片段的反向重复序列植物表达载体p23700,其转录产物能形成发夹RNA(hpRNA),产生小分子干扰RNA,干扰目的基因的表达.将p23700质粒导入根癌农杆菌EHA105中并转化烟草叶片细胞,经选择分化培养,获得表型矮化的转基因烟草.图4参14  相似文献   

11.
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   

12.
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   

13.
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   

14.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

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