DNA自动测序技术进展

ＤＮＡ测序是遗传工程的重要技术之一,ＤＮＡ测序技术的自动化对遗传工程的研究具有重要意义。七十年代末期,Ｓａｎｇｅｒ和Ｍａｘａｍ,Ｇｉｌｂｅｒｔ分别提出了切实可行的ＤＮＡ序列测定方法。近二十年来,ＤＮＡ测序技术发展很快。人们从不同方面对该技术进行了改进,并将许多先进的光学探测方法应用于ＤＮＡ测序技术中。目前已出现了许多商品化的ＣＮＡ测序仪。     

一种供RAPD分析用蜘蛛模板DNA的快速提取方法

简要介绍了一种高效、快速提取蜘蛛模板 Ｄ Ｎ Ａ 供 Ｒ Ａ Ｐ Ｄ 分析的方法⒚该方法具有快速简便、重复性好的优点,提取的 Ｄ Ｎ Ａ 无污染物产生,完全能满足 Ｒ Ａ Ｐ Ｄ 研究的需要⒚     

福尔马林固定云南鲴的DNA提取及其细胞色素b基因序列分析

福尔马林固定云南鲴的ＤＮＡ提取及其细胞色素ｂ基因序列分析ＤＮＡＥＸＴＲＡＣＴＥＤＦＲＯＭＦＯＲＭＡＬＩＮ－ＦＩＸＥＤＸｅｎｏｃｙｐｒｉｓｙｕｎｎａｎｅｎｓｉｓＡＮＤＳＥＱＵＥＮＣＥＡＮＡＬＹＳＩＳＯＦＩＴＳＣＹＴＯＣＨＲＯＭＥＢＧＥＮＥ关键词福尔马林...     

应用放射性自显影技术检测外源DNA与鸡精子的结合

应用放射性自显影技术检测外源ＤＮＡ与鸡精子的结合ＤＥＴＥＣＴＩＮＧＡＳＳＯＣＩＡＴＩＯＮＯＦＥＸＯＧＥＮＯＵＳＤＮＡＷＩＴＨＣＨＩＣＫＥＮＳＰＥＲＭＵＳＩＮＧＡＵＴＯＲＡＤＩＯＧＲＡＰＨＹ关键词鸡，精子，脂质体，ＤＮＡ与精子的结合ＫｅｙｗｏｒｄｓＣｈ...     

DNA分析技术及其在植物系统学研究中的应用

ＤＮＡ分析技术及其在植物系统学研究中的应用贺新强,李法曾（山东师范大学生物系,济南２５００１４）ＤＮＡＡＮＡＬＹＺＩＮＧＴＥＣＨＮＩＱＵＥＳＡＮＤＩＴＳＡＰＰＬＩＣＡＴＩＯＮＩＮＰＬＡＮＴＳＹＳＴＥＭＡＴＩＣＳＲＥＳＥＡＲＣＨ￥ＨｅＸｉｎ－ｑｉａｎｇ...     

DNA 测序技术领域的相关政府投入分析

DNA测序技术是遗传工程的核心技术之一,发展快速和低成本的基因测序技术成为研究焦点。美国、欧盟等发达国家和地区大力支持DNA测序技术的创新研究,并投入了大量的科研经费。在美国,国家卫生研究院(NIH)下属的国家人类基因组研究院(NHGRI)、美国能源部(DOE)以及美国科学基金委(NSF)等机构是进行DNA测序技术相关项目经费分配的主要政府部门。DNA测序作为生命科学研究的关键技术也是欧盟框架计划资助的重要内容之一,其以多个欧洲国家间合作以及产学研合作的形式开展。中国在DNA测序技术领域也开展了一些研究。     

普通小麦细胞质雄性不育系及其保持系线粒体DNA和RAPD分析

应用随机扩增多态ＤＮＡ（Ｒａｎｄｏｍ ａｍｐｌｉｆｉｅｄ ｐｏｌｙｍｏｒｐｈｉｃ ＤＮＡｓ,ＲＡＰＤ）技术,对普通小麦细胞质雄性不育系（Ａ）及其保持系（Ｂ）线粒体基因组（ｍｉｔｏｃｈｏｎｄｒｉａｌ ｇｅｎｏｍｅ）的指纹图谱进行了分析。共使用引物４１个,其中２０个引物得到了扩增产物,部分引物扩增结果表现多态性。说明线粒体ＤＮＡ（ｍｉｔｏｃｈｏｎｄｒｉａｌ ＤＡＮ,ｍｔ,ＤＮＡ）序列在不育系和保持系之     

耐盐辣椒分子育种

利用自花授粉后形成的花粉管通道将海岸耐盐植物红树总 Ｄ Ｎ Ａ 导入辣椒,其后代的耐盐性明显增强,在海滩上试种,用海水直接浇灌,约５５％ 的转化株能开花、结果,而对照株全部死亡。进行蛋白质 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ电泳和 Ｒ Ａ Ｐ Ｄ 分析,分别发现一条１７５ Ｋ Ｄ蛋白质和一条１１ Ｋｂ Ｄ Ｎ Ａ 的特异性谱带,表明通过花粉管通道导入外源 Ｄ Ｎ Ａ 是可行的,其后代植株耐盐能力提高与基因组变异有关。     

花生种子高纯度DNA的提取（简报）

花生种子高纯度ＤＮＡ的提取（简报）王艳,何军贤,傅家瑞（中山大学生命科学学院,广州５０２７５）关键词花生;种子;ＤＮＡ;十六烷基三甲基溴化铵ＲＡＰＩＤＡＮＤＥＦＦＩＣＩＥＮＴＰＵＲＩＦＩＣＡＴＩＯＮＯＦＤＮＡＦＲＯＭＰＥＡＮＵＴ（ＡＲＡＣＨＩＳＨＹＰ...     

文摘

０００００１ＤＮＡ自动测序技术进展［中］／李玉栋…／／生物工程进展．－１９９９,１９（５）．－６７～７１ＤＮＡ测序是遗传工程的重要技术之一,ＤＮＡ测序技术的自动化对遗传工程的研究具有重要意义。七十年代末期,Ｓａｎｇｅｒ和Ｍａｘａｍ、Ｇｉｌｂｅｒｔ分别...     

N13D、S40E点突变提高木聚糖酶XYNB的热稳定性

对来源于Streptomyces olivaceoviridis的高比活木聚糖酶XYNB进行同源建模和序列比较,设计了N13D、S40E的定点突变,以期改善中温酶XYNB的热稳定性。突变酶N13D、S40E分别在毕赤酵母中表达,经纯化后与野生型酶XYNB(同样经毕赤酵母表达后纯化)进行酶学性质比较,结果表明,突变酶N13D和S40E在70℃处理5min,热稳定性比XYNB分别提高了24.76%和14.46%;突变酶N13D的比活性比XYNB提高了22%。在其他性质方面突变酶N13D、S40E与野生型酶XYNB基本相似。通过对木聚糖酶XYNB的定点突变,提高了该酶的热稳定性,并为结构与功能的进一步研究提供了材料。     

Synthesis,luminescence, and excited-state absorption properties of disubstituted perylene diimide derivatives modified at bay region

Three A–π–A or D–π–D perylene diimide ( PDI ) derivatives with varied groups on π-conjugate were synthesized and characterized. The photophysical properties of these compounds were systematically studied by spectral experiments and density functional theory calculations. All compounds displayed intense absorption bands at 300–800 nm wavelengths. However, diverse groups on the π-conjugate influenced the UV–vis absorption. Electron-withdrawing groups on PDI-2 caused a slight red shift at the 350–400 nm wavelength and a blue shift after 400 nm wavelength. At the same time, the electron-donating substituents on PDI-3 caused an obvious red shift of this band. These PDI derivatives exhibited emission in solution at room temperature (λ_em = 500–850 nm). The quantum yield of PDI-3 decreased, while the electron-donating substituents were introduced to the π-conjugated motifs. However, the quantum yield of PDI-2 increased when electron-withdrawing substituents were introduced to the π-conjugated motifs. In addition, PDI-1 and PDI-2 exhibited broad triplet transient absorption in the visible region. These photophysical properties could help us to understand the relationship between structure and photophysical properties of perylene diimide derivatives and exploit more original perylene diimide-based optical functional materials.     

Pilot study to assess the validity of the single assessment process as a screening tool for dental treatment needs in older people

Objective: To assess the feasibility of using a questionnaire‐based needs assessment tool (D‐E‐N‐T‐A‐L) to screen for dental treatment need as part of the single assessment process (SAP) for older people in Sheffield. Materials and methods: Test validation study comparing questionnaire‐assessed and normative need in two consecutive samples of older adults: 48 living at home in the transition phase of older age and 29 frail older adults living in care homes. Each answered the six D‐E‐N‐T‐A‐L questions as part of SAP and a dental examination was carried out within 2 weeks in participants’ homes. Question‐defined need was then compared to the normative need. Results: Questionnaire‐defined and normative need were high in both the transitional group (83% and 90% respectively) and the frail group (83% and 62%). These high levels of need meant that the sensitivity and positive predictive values of D‐E‐N‐T‐A‐L were high, but the specificity and negative predictive values were low. Conclusion: The high levels of need in these patient groups suggests that preliminary questionnaire‐based screening is an unnecessary step. A clinical examination of all older people undergoing SAP may be necessary. Further research may be warranted on the use of questionnaires to assess dental treatment needs among people with different attendance patterns.     

An impulsively controlled pest management model with n predator species and a common prey

This paper investigates the dynamics of a competitive single-prey n-predators model of integrated pest management, which is subject to periodic and impulsive controls, from the viewpoint of finding sufficient conditions for the extinction of prey and for prey and predator permanence. The per capita death rates of prey due to predation are given in abstract, unspecified forms, which encompass large classes of death rates arising from usual predator functional responses, both prey-dependent and predator-dependent. The stability and permanence conditions are then expressed as balance conditions between the cumulative death rate of prey in a period, due to predation from all predator species and to the use of control, and to the cumulative birth rate of prey in the same amount of time. These results are then specialized for the case of prey-dependent functional responses, their biological significance being also discussed.     

Linked selected and neutral loci in heterogeneous environments

We analyze a system of ordinary differential equations modeling haplotype frequencies at a physically linked pair of loci, one selected and one neutral, in a population consisting of two demes with divergent selection regimes. The system is singularly perturbed, with the migration rate m between the demes serving as a small parameter. We use geometric singular perturbation theory to show that when m is sufficiently small, each solution not initially fixed for the same selected allele in both demes approaches one of a 1-dimensional continuum of equilibria. We then obtain asymptotic expansions of the solutions and show their validity on arbitrarily long finite time intervals. From these expansions we obtain formulas for the transient dynamics of F _ST (a measure of population structure) at both loci, as well as for the rate of genotyping error if the allelic state at the selected locus is inferred from that at the neutral (marker) locus. We examine two cases in detail, one modeling two populations in secondary contact after a period of evolution in allopatry, and the other modeling the origination and spread of a resistance allele.Electronic supplementary material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00285-006-0038-6 and is accessible for authorized users.     

Influenza A: From highly pathogenic H5N1 to pandemic 2009 H1N1. Epidemiology and clinical features

The last decade has seen the emergence of two new influenza A subtypes and they have become a cause of concern for the global community. These are the highly pathogenic H5N1 influenza A virus (H5N1) and the Pandemic 2009 influenza H1N1 virus. Since 2003 the H5N1 virus has caused widespread disease and death in poultry, mainly in south East Asia and Africa. In humans the number of cases infected with this virus is few but the mortality has been about 60%. Most patients have presented with severe pneumonia and acute respiratory distress syndrome. The second influenza virus, the pandemic H1N1 2009, emerged in Mexico in March this year. This virus acquired the ability for sustained human to human spread and within a few months spread throughout the world and infected over 4 lakh individuals. The symptoms of infection with this virus are similar to seasonal influenza but it currently affecting younger individuals more often. Fortunately the mortality has been low. Both these new influenza viruses are currently circulating and have different clinical and epidemiological characteristics.     

Multiple limit cycles in the chemostat with variable yield

The global asymptotic behavior of solutions of the variable yield model is determined. The model generalizes the classical Monod model and it assumes that the yield is an increasing function of the nutrient concentration. In contrast to the Monod model, it is demonstrated that the variable yield model exhibits sustained oscillations. Moreover, it is shown that the variable yield model may undergo a subcritical Hopf bifurcation and feature at least two distinct limit cycles. Implications for the coexistence of competing populations are discussed.     

Reduction of slow-fast discrete models coupling migration and demography

This work deals with a general class of two-time scales discrete nonlinear dynamical systems which are susceptible of being studied by means of a reduced system that is obtained using the so-called aggregation of variables method. This reduction process is applied to several models of population dynamics driven by demographic and migratory processes which take place at two different time scales: slow and fast. An analysis of these models exchanging the role of the slow and fast dynamics is provided: when a Leslie type demography is faster than migrations, a multi-attractor scenario appears for the reduced dynamics; on the other hand, when the migratory process is faster than demography, the reduction process gives rise to new interpretations of well known discrete models, including some Allee effect scenarios.     

Discrete-time host–parasitoid models with pest control

We propose a simple discrete-time host–parasitoid model to investigate the impact of external input of parasitoids upon the host–parasitoid interactions. It is proved that the input of the external parasitoids can eventually eliminate the host population if it is above a threshold and it also decreases the host population level in the unique interior equilibrium. It can simplify the host–parasitoid dynamics when the host population practices contest competition. We then consider a corresponding optimal control problem over a finite time period. We also derive an optimal control model using a chemical as a control for the hosts. Applying the forward–backward sweep method, we solve the optimal control problems numerically and compare the optimal host populations with the host populations when no control is applied. Our study concludes that applying a chemical to eliminate the hosts directly may be a more effective control strategy than using the parasitoids to indirectly suppress the hosts.