活性污泥总DNA不同提取方法的比较

为了快速、简便和经济地获得活性污泥的总DNA,以用于分子生物学研究,采用5种不同的DNA提取方法提取活性污泥的总DNA,并通过提取的核酸总量、纯度、是否含有聚合酶链反应抑制剂等指标综合分析不同的提取方法对活性污泥总DNA提取效果的影响.结果表明:蛋白酶K-SDS-酚氯仿法和柱提取DNA试剂盒法提取活性污泥总DNA效果最好,提取DNA总量多,纯度高,可不经纯化直接进行PCR扩增反应。     

快速提取用于PCR分析的几种蔬菜DNA的方法

利用两种不同的简便方法提取大白菜、大葱和厚皮酣瓜发芽种子的DNA，均能产生具有重现性的RAPD结果这两种方法提取DNA的PCR扩增结果与多次利用苯酚／氯仿提取DNA的结果一致.RNase处理与否对提取DNA的PCR扩增结果没有影响.方法1不用氯仿，但残留蛋白质等容易造成DNA溶解困难；方法2提取的DNA纯度高对于含蛋白质较少的植物器官或组织，可以选用方法1，而对于含蛋白质较多的植物器官或组织，宜选用方法2.两种方法提取的DNA量与用苯酚／氯仿提取DNA的量相似样品之间提取DNA量的多少主要受研磨破碎程度高低所决定.方法1每人每天提取约120个样品，方法2提取约100个样品，比先前的方法快1倍多.所提取的每个样品DNA约能用于100次PCR反应，两种DNA提取方法简便、迅速，为快速进行大量样品的PCR分析提供了条件.     

电化学DNA生物传感器在检测环境有机污染物中的应用

电化学DNA生物传感器是一种以DNA为生物识别元件并通过电化学信号转换器将目标物的存在转变为可检测的电信号的传感装置.因具有灵敏性高、选择性好、制备成本低、操作简单、携带方便、抗干扰性强等优点而被广泛用于环境分析领域.本文简要阐述了电化学DNA生物传感器的检测原理及DNA在电极表面的固定化方法,重点讨论了电化学DNA生物传感器在检测环境有机污染物中的应用,最后对电化学DNA生物传感器的发展方向进行了展望.     

真菌核酸的一种快速提取方法

在总结多种真菌DNA和RNA提取方法的基础上，发展了一种提取真菌核酸新方法，与其它方法相比，该方法具有快速、操作简便等特点，而且提取DNA和RNA步骤基本一致，用该方法提取的DNA完整、纯度高，可用于PR、限制性内切酶酶切和Southern杂交等分子生物学操作；提取RNA产量高，RNA无降解，纯度高，适用Northern和cDNA合成等分子生物学操作。     

海洋微藻活体及乙醇固定状态下基因组DNA的微量提取方法

探讨了海洋微藻活体及固定状态下基因组DNA的提取方法,即作者改进的CTAB法.结果表明,CTAB改进法提取的基因组DNA蛋白质、酚、盐和小分子的污染较少,多糖成份也得到了有效去除.用5%乙醇固定样本提取DNA的效果最好,对原生动物抑制效果也较明显;10%以上的乙醇可杀死原生动物,但对DNA的降解率较大;30%以上的乙醇对细菌抑制较明显,但DNA都有较大程度的降解.本法提取的DNA可用于正常的酶切和PCR.用甲醛、甲醇/冰醋酸等其它固定液固定样品,DNA的得率低或者质量和纯度低.图7表1参27     

识别黄山药、穿龙薯蓣和盾叶薯蓣的分子标记建立

在对黄山药、穿龙薯蓣和盾叶薯蓣的psbA-trnH片段序列分析的基础上,根据3种薯蓣在该片段上的特征序列位点设计了用于识别3种薯蓣的寡核苷酸片段,并作为PCR反应的引物,将3种薯蓣的特征标记引物与psbAf-trn-Hr配合使用建立了识别3种薯蓣的显性和共显性两种检测方式,辅以NaOH碱法快速提取薯蓣干燥根茎总DNA,为3种薯蓣相互间快速、准确的鉴别创造了条件.图3表2参9     

浮游植物叶绿素a测定方法比较

选取规范方法、超声波法、反复冻融法、延时提取法、热丙酮法、丙酮加热法、热乙醇法、混合溶剂法8种常见的浮游植物叶绿素a的测定方法,以实验室培养的微囊藻(Microcystis aeruginosa)水华样品为研究对象进行叶绿素a含量的测定.从叶绿素a提取的完全性、测定数据的稳定性、试验操作的简便性等方面对8种方法进行评价,并对叶绿素a结果测量的单色法和三色法进行分析讨论.试验结果表明,选取的8种测定方法中,包括国家标准方法在内的大多数方法,存在操作耗时长、过程复杂、叶绿素提取不完全的缺点;而丙酮加热法测量叶绿素a的提取效率高、数据稳定性好,操作耗时短、简便,可推荐作为一种常用的浮游植物叶绿素a的测量方法;三色法和单色法测定方法的选取应综合考虑.     

微波辅助提取-氢化物发生原子荧光光谱法测定土壤中As（Ⅲ）和As（Ⅴ）

建立了微波辅助提取,采用氢化物发生原子荧光光谱法不进行价态分离,直接测定土壤中As（Ⅲ）和As（Ⅴ）的方法。通过加入抗坏血酸作为抗氧化剂,以磷酸溶液、L-半胱氨酸分别为提取剂和还原剂,在不还原与还原两种情况下分别进行测量,根据荧光强度与As（Ⅲ）和As（Ⅴ）的质量浓度关系方程式计算提取液中它们的质量浓度。对实验条件进行优化后,As（Ⅲ）、As（Ⅴ）的方法检出限均可达到0.05μg.g-1,实验精密度（RSD,n=11）分别为1.3%和2.1%,样品加标平均回收率分别为As（Ⅲ）为93.2%~110.0%,As（Ⅴ）为92.6%~104.0%。该方法不需要高效液相色谱等大型设备、简单可靠、易于操作、分析速度快、精密度高,具有在各分析测试实验室推广应用价值。方法已用于实际土壤样品中不同价态无机砷质量分数的测定。     

白菜叶绿体DNA快速提取及分析

采用SDS-蛋白酶法提取了白菜的叶绿体DNA.琼脂糖电泳及紫外分光光度分析表明,所提取的叶绿体DNA质量高,除cpDNA主环外,在胞质雄性不育新种质及原不育系中还存在约1375bp和831bp的两条质粒分子.用所提取的叶绿体DNA作为模板进行RAPD扩增,获得了清晰的扩增图谱.该方法与传统的提取方法相比省时、高效、无污染.图2表1参14     

中孔硅镁胶对水溶液中磷酸根的吸附性能

化肥、农药、含磷洗涤剂以及粪便,是废水中磷的主要来源,而磷浓度超标是引起水体中富营养化的主要原因之一.目前,国内外除磷的方法中主要有化学沉淀法、物理吸附法、离子交换法和微生物降解法等,吸附法因其工艺简单、运行可靠、操作灵活和无二次污染等特点备受关注.硅酸镁为多孔结构,属两性化合物,具有酸碱两种吸附性能,在聚醚精制过程中用于脱酸、脱臭、脱色及脱钾,在煎炸油处理和生物柴油加工过程中用于降低酸价;此外,硅酸镁还广泛地应用于脱除废水中的金属离子和染料.目前,国内外对三硅酸镁和六硅酸镁的报道较多,对其它镁硅配比的硅酸镁报道较少.本课题组系统地研究了不同镁硅物质的量之比的     

Achieving Open Access to Conservation Science

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     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

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.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

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.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

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.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

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.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Cost‐effective conservation of an endangered frog under uncertainty

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.