裂褶菌F17对偶氮染料刚果红的脱色降解及其产物分析

利用本实验室新构建的染料脱色降解体系,对裂褶菌F17(Schizophyllum sp.F17)脱色降解刚果红进行了研究,分析了该菌的主要降解酶,并对刚果红降解产物进行分离和鉴定.结果表明,裂褶菌F17在此体系中对刚果红表现出较高的脱色降解能力,菌球加入48h后脱色率达到91.5%;酶活检测表明,该菌主要产生锰过氧化物酶(MnP),并在脱色48h时,MnP酶活达到最大值96.1U·L-1.此外,对脱色96h和192h后的脱色液进行紫外-可见扫描,发现刚果红在可见光区495nm处的吸收峰已消失,并在紫外区出现多个吸收峰.通过高效液相色谱分离得到1种刚果红降解产物,用质谱和傅立叶红外光谱鉴定,发现该产物相对分子量为184.2,主要官能团为-C6H4-和芳基-NH2,结合刚果红结构和该产物的核磁共振波谱推断其为联苯胺;并且随着降解时间的延长,联苯胺逐渐被降解.     

降解聚丁二酸丁二醇酯菌株的诱变选育及降解性能

诱变选育是基因资源开发的重要手段之一,为了对降解聚丁二酸丁二醇酯(PBS)菌株的降解性能进行改良,选择具有一定降解PBS能力的尖孢镰刀菌(Fusarium oxysporum)DSCF-8为出发菌株,分别研究了其在5种诱变途径下的突变效应及最佳诱变条件,测定了突变菌株D8B14在不同条件下的降解性能。结果表明,复合诱变途径的高效降解菌株获得率大于单因子诱变途径,分别达到了4.55%和1.30%,但突变株的降解特性遗传不稳定;硫酸二乙酯单因子诱变效应大于紫外线诱变和微波诱变,且得到的突变株较复合诱变得到的菌株具有更强的遗传稳定性,最佳诱变条件为5%的浓度处理40 min。硫酸二乙酯诱变得到的突变株D8B14传代稳定且降解性能优异,其对PBS薄膜的降解率较出发菌株提高了34.49%,粗酶液酶活性提高率为23.86%。该突变株在35℃条件下仍表现出较高的降解能力,对不同的初始pH条件亦具有更强的耐受能力,尤其在pH 4.0或pH 9.0的酸性和碱性条件下,降解率分别提高了13.26%和27.04%。     

Identification of naphthalene metabolism by white rot fungus Armillaria sp. F022

Armillaria sp. F022, a white rot fungus isolated from tropical rain forest (Samarinda, Indonesia) was used to biodegrade naphthalene in cultured medium. Transformation of naphthalene by Armillaria sp. F022 which is able to use naphthalene, a two ring-polycyclic aromatic hydrocarbon (PAH) as a source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that Armillaria sp. F022 initiates its attack on naphthalene by dioxygenation at its C-1 and C-4 positions to give 1,4-naphthoquinone. The intermediate 2-hydroxybenzaldehyde and salicylic acid, and the characteristic of the meta-cleavage of the resulting diol were identified in the long-term incubation. A part from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as the next intermediate for the naphthalene pathway of this Armillaria sp. F022. Neither phthalic acid, catechol and cis,cis-muconic acid metabolites were detected in culture extracts. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Armillaria sp. F022 were detected during the incubation.     

变性高效液相色谱在大通量筛查基因突变中的应用

应用变性高效液相色谱(DHPLC)对已知序列的含外显子7的斑马鱼p53基因片段PCR产物进行突变检测,结果表明,通过克隆测序方法检测出的点突变,用DHPLC同样可以检出.且对该片段的最优化检测柱温为60℃,其特异性很好,敏感性大于95%.     

DNA聚合酶对PCR方法检测基因点突变的干扰分析

以野生型斑马鱼p53基因外显子7为目的片段,运用变性高效液相色谱(DHPLC),比较分析三种常用的商品DNA聚合酶对聚合酶链式反应(PCR)技术检测基因点突变的影响.DHPLC检测结果显示,Promega Shanghai公司Taq DNA聚合酶,Promega公司Taq DNA聚合酶和BD Biosciences公司高保真酶Advantage-HF2的分子突变频率分别为14.3%,5.95%和0.76%.通过DNA直接测序法确认表明,Promega公司Taq DNA聚合酶和BD Biosciences公司高保真酶Advantage-HF2的碱基突变频率分别为3.61×10-4和7.69×10-5.研究表明,不同的DNA聚合酶对PCR技术的检测结果有明显影响,高保真酶Advantage-HF2所造成的碱基错配率明显低于其它两种商业化Taq酶.     

A role for selective contraception of individuals in conservation

Contraception has an established role in managing overabundant populations and preventing undesirable breeding in zoos. We propose that it can also be used strategically and selectively in conservation to increase the genetic and behavioral quality of the animals. In captive breeding programs, it is becoming increasingly important to maximize the retention of genetic diversity by managing the reproductive contribution of each individual and preventing genetically suboptimal breeding through the use of selective contraception. Reproductive suppression of selected individuals in conservation programs has further benefits of allowing animals to be housed as a group in extensive enclosures without interfering with breeding recommendations, which reduces adaptation to captivity and facilitates the expression of wild behaviors and social structures. Before selective contraception can be incorporated into a breeding program, the most suitable method of fertility control must be selected, and this can be influenced by factors such as species life history, age, ease of treatment, potential for reversibility, and desired management outcome for the individual or population. Contraception should then be implemented in the population following a step‐by‐step process. In this way, it can provide crucial, flexible control over breeding to promote the physical and genetic health and sustainability of a conservation dependent species held in captivity. For Tasmanian devils (Sarcophilus harrisii), black‐flanked rock wallabies (Petrogale lateralis), and burrowing bettongs (Bettongia lesueur), contraception can benefit their conservation by maximizing genetic diversity and behavioral integrity in the captive breeding program, or, in the case of the wallabies and bettongs, by reducing populations to a sustainable size when they become locally overabundant. In these examples, contraceptive duration relative to reproductive life, reversibility, and predictability of the contraceptive agent being used are important to ensure the potential for individuals to reproduce following cessation of contraception, as exemplified by the wallabies when their population crashed and needed females to resume breeding.     

Firms' and states’ responses to laxer environmental standards

On June 1, 2017, President Trump announced the United States' withdrawal from the Paris agreement on climate change. Despite this decision, American firms continued investing in low-carbon technologies and some states committed to tougher environmental standards. To understand this apparent paradox, this paper studies how a weakening of environmental standards affects the behavior of profit-maximizing firms. It finds that a relaxation of emission standards (i) may increase firms’ incentives to adopt clean technologies, but not to pollute less; (ii) may negatively affect industry profitability if it is perceived as temporary; and, when this is the case, (iii) the unilateral adoption of stricter standards by large states may increase the expected profitability of every firm.     

Alternatives to biodiversity offsets for mitigating the effects of urbanization on stream ecosystems

Globally, offset schemes have emerged in many statutory frameworks relating to development activities, with the aim of balancing biodiversity conservation and development. Although the theory and use of biodiversity offsets in terrestrial environments is broadly documented, little attention has been paid to offsets in stream ecosystems. Here we examine the application of offset schemes to stream ecosystems and explore whether they suffer similar shortcomings to those of offset schemes focused on terrestrial biodiversity. To challenge the applicability of offsets further, we discuss typical trajectories of urban expansion and their cascading physical, chemical and biological impacts on stream ecosystems. We argue that the highly connected nature of stream ecosystems and urban drainage networks can transfer impacts of urbanization across wide areas, complicating the notion of like‐for‐like exchange and the prospect of effectively mitigating biodiversity loss. Instead, we identify in‐catchment options for stormwater control, which can avoid or minimize the impacts of development on downstream ecosystems, while presenting additional public and private benefits. We describe the underlying principles of these alternatives, some of the challenges associated with their uptake, and policy initiatives being trialed to facilitate adoption. In conclusion, we argue that stronger policies to avoid and minimize the impacts of urbanization provide better prospects for protecting downstream ecosystems, and can additionally, stimulate economic opportunities and improve urban liveability.     

Participatory development of incentives to coexist with jaguars and pumas

Reducing costs and increasing benefits for rural communities coexisting with large carnivores is necessary for conservation of jaguar (Panthera onca) and puma (Puma concolor). To design acceptable incentives, stakeholders must be involved in the process. We conducted an innovative, structured, group communication process based on a Delphi technique as a template for identifying potential incentives. Community workshops with 133 members of 7 communities and surveys with 25 multidisciplinary experts from government, nongovernmental organizations, and academia provided iterative data to design a plan of incentives through 4 rounds of discussion. The final product integrated 862 ideas into 6 types of incentives: organization of communities, mechanisms for improved dialogue, citizen technical assistance, green labeling for community products, payment for the ecosystem service of biodiversity, and an assessment of financial alternatives. We used quantitative and qualitative techniques to indicate support for decisions about the design of incentives, which reduced researcher subjectivity. The diverse incentives developed and the cooperation from multiple stakeholders resulted in an incentive plan that integrated issues of governance, equity, and social norms.     

Cost shifting and other perverse incentives in biodiversity offsetting in India

Biodiversity offsetting aims to compensate for development‐induced biodiversity loss through commensurate conservation gains and is gaining traction among governments and businesses. However, cost shifting (i.e., diversion of offset funds to other conservation programs) and other perverse incentives can undermine the effectiveness of biodiversity offsetting. Additionality—the requirement that biodiversity offsets result in conservation outcomes that would not have been achieved otherwise—is fundamental to biodiversity offsetting. Cost shifting and violation of additionality can go hand in hand. India's national offsetting program is a case in point. Recent legislation allows the diversion of offset funds to meet the country's preexisting commitments under the United Nations Framework Convention on Climate Change (UNFCCC) and United Nations Convention on Biological Diversity (CBD). With such diversions, no additional conservation takes place and development impacts remain uncompensated. Temporary additionality cannot be conceded in light of paucity of funds for preexisting commitments unless there is open acknowledgement that fulfillment of such commitments is contingent on offset funds. Two other examples of perverse incentives related to offsetting in India are the touting of inherently neutral offsetting outcomes as conservation gains, a tactic that breeds false complacency and results in reduced incentive for additional conservation efforts, and the clearing of native vegetation for commercial plantations in the name of compensatory afforestation, a practice that leads to biodiversity decline. The risks accompanying cost shifting and other perverse incentives, if not preempted and addressed, will result in net loss of forest cover in India. We recommend accurate baselines, transparent accounting, and open reporting of offset outcomes to ensure biodiversity offsetting achieves adequate and additional compensation for impacts of development.