栖霞市土地利用空间格局的邻域关系

基于ArcGIS软件中的邻域统计模块和空间分析模块,借助邻域因子从空间和时间两个维度分别对1987—2003年间山东省栖霞市主要地类邻域关系的变化趋势进行了分析.结果表明：栖霞市不同地类之间的邻域关系随着邻域距离的增加不断增加;同种地类的邻域相关程度均表现为聚集现象,其随着邻域距离的增加不断降低;1987—2003年间,栖霞市建设用地与园地、园地与林地之间的邻域相关程度呈下降趋势,建设用地与林地、建设用地与草坡地之间的邻域相关程度呈增加趋势.控制建设用地规模、加强对耕地的保护、降低人类活动强度对林地、草坡地等自然景观的干扰,是实现栖霞市经济、生态效益协调发展的重要途径.     

氯酚类化合物的微生物降解研究进展

综述了近年在具有降解氯酚类化合物能力的微生物的筛选、氯酚类化合物的好氧和厌氧降解机制以及现代生物技术的开发利用研究．阐述了氯酚类化合物在不同条件下的降解路径．在好氧条件下,单氯酚和二氯酚在氧化酶的攻击下形成氯代邻二酚,邻二酚开环生成相应的氯代粘康酸或半醛,粘康酸内酯化过程中释放氯离子;高度氯代的化合物则是在氢氧化酶作用下生成氯代醌,并逐步脱去所有的氯原子生成苯酚后才开环．在厌氧或缺氧条件下,氯酚进行还原脱氯,在得到电子的同时去掉一个氯取代基．     

好氧活性污泥体系中磺胺类抗生素生物降解的研究进展

磺胺类抗生素(Sulfonamides,SAs)是一类被广泛应用于医疗和畜禽养殖的抗菌药物,但其在人和动物肠道中的可降解性较差,会通过人及畜禽粪便和尿液的排放进入污水处理系统。目前,污水处理厂中的好氧活性污泥(Aerobic activated sludge,AAS)被证实能够有效转化SAs。文中基于对国内外文献的调研,总结了好氧活性污泥体系中SAs生物降解的研究进展,对生物降解机理、主要的生物降解途径和影响降解效率的环境因素进行了梳理与回顾,并针对现有研究的不足提出展望,以期为优化污水处理厂中SAs的生物降解提供科学依据。     

西藏高原天然长芒草地丛枝菌根真菌接种效应

采用草地均匀打孔方法,就草地土壤未消毒条件下接种丛枝菌根（AM）真菌对长芒草(Stipa bungeana)的侵染效应以及对植物生长、吸磷效率、土壤微生物区系等的影响进行研究.结果表明,1)接种处理、不接种处理的菌根效应存在着明显的差异,多数接种处理根围土壤AM真菌孢子密度、菌根侵染率和侵染强度显著提高,但对丛枝丰度的影响相对较低.2)接种后AM真菌孢子密度对菌根侵染率具有极显著影响(r=0.7679**);随菌根侵染率的增加,植株总干物重和吸磷总量均呈极显著提高,r值分别为0.7556**、0.8018**.3)与植株地上部相比,接种AM真菌对提高根系干物重、根系吸磷量和含磷量的促进作用相对较大.4)多数接种处理根际土壤酸性磷酸酶、碱性磷酸酶活性均呈一定程度的提高,根际土壤细菌数量显著增加,真菌、放线菌的数量变化则不甚明显.5)各接种处理对寄主植物的综合侵染效应在总体上呈Glomus mosseae+G. intraradices+Scutellospora calospora＞G. mosseae+G. aggregatum＞Glomus sp.＞G. mosseae＞G. mosseae+ G. etunicatum+G. intraradices+S. erythropa＞G. geosporum的趋势.     

聚乙烯醇生物降解研究进展

聚乙烯醇(PVA)是一种在纺织和化工行业中广泛使用的难降解的高分子聚合物。随着人们对纺织工业清洁生产的关注,如何在退浆工艺中就实现对PVA的生物降解、减少PVA废水的排放,并避免化学退浆过程中高温和氧化造成的棉纤维损伤,是近年来纺织生物技术领域的研究热点。由于PVA降解菌种类不多、培养周期长,PVA降解酶酶活不高、提取不容易等原因,使PVA的生化降解研究还局限在PVA降解菌的筛选、PVA降解酶的酶学性质研究等方面,PVA降解酶还未在纺织工业上得到应用。本文综述了近年来国内外在PVA降解菌筛选、PVA降解酶提取及酶学性质、PVA生化降解机理等方面的研究进展,并讨论了PVA生化降解研究中存在的问题及发展方向。     

塑料生物降解检测方法的研究进展

塑料处理不当造成的污染问题已成为全球性难题。目前的解决办法除回收利用与使用可生物降解塑料替代之外,最主要途径仍是寻求高效的塑料降解方法。其中,采用微生物或酶处理塑料的方法因其具有条件温和、不产生次生环境污染的优势而受到越来越多的关注。塑料生物降解技术的核心是高效解聚微生物/酶,然而当前的分析检测方法无法满足塑料生物降解资源的高效筛选,因此开发准确、快速的塑料降解过程分析方法,对于生物降解资源筛选和降解效能评价具有重要意义。本文介绍了近年来在塑料生物降解领域的常用分析检测技术,包括高效液相色谱、红外光谱、凝胶渗透色谱以及透明圈测定等,重点讨论了荧光分析策略在快速表征塑料生物降解过程中的应用,为进一步规范塑料生物降解过程的表征与分析研究,以及开发更高效的塑料生物降解资源筛选方法提供借鉴。     

聚乙烯塑料生物降解研究进展

聚乙烯(polyethylene,PE)塑料是全球通用合成树脂中产量最丰富的品种,也是最难降解的塑料之一,其在环境中大量积累已造成严重的生态污染。传统的垃圾填埋、堆肥和焚烧处理技术难以满足生态环境的保护要求,生物降解是解决塑料污染问题的一种生态友好、成本低廉、前景可期的方法。本文对PE塑料的化学结构、降解微生物的种类、降解酶和代谢途径等方面进行了综述,结合国内外PE塑料生物降解的前沿和热点问题,建议重点开展高效降解菌株筛选、人工合成菌群构建、降解酶的挖掘与改造等方面的研究,为PE塑料生物降解研究提供路径选择和理论借鉴。     

一株金黄杆菌对2-吡啶甲酸的好氧生物降解

【背景】2-吡啶甲酸具有高毒性、致癌性,能长期稳定存在于水体中,从而对环境造成危害。【目的】开发一种能够高效经济处理含2-吡啶甲酸废水的技术。【方法】筛选一株在好氧条件下以2-吡啶甲酸为唯一碳、氮、能源的菌株,考察该菌株的降解性能,建立降解动力学模型。【结果】经过16S r RNA基因序列分析,该菌株被鉴定为金黄杆菌(Chryseobacterium sp.),命名为ZD2。当2-吡啶甲酸初始浓度为100、200、400、600和800 mg/L时,ZD2完全降解2-吡啶甲酸的时间分别为10、18、22、78和114 h。零级动力学模型较好地描述了2-吡啶甲酸的降解行为,当初始浓度为100-400 mg/L时,降解速率常数随着浓度的增加而增加,并于400 mg/L时达到最大;600-800 mg/L时,降解速率常数开始下降,呈现抑制作用。【结论】菌株ZD2对2-吡啶甲酸的降解效果较好,能够为处理实际的2-吡啶甲酸工业废水提供理论依据。     

聚乙烯醇的生物降解

聚乙烯醇(PVA)是较少的可溶于水并被生物降解的乙烯聚合物之一。研究表明,在受PVA污染的自然环境中存在着能降解PVA的微生物,并从中提取出了PVA降解酶。介绍了国内外研究聚乙烯醇生物降解的情况。分别讨论了聚乙烯醇被单一菌种、共生细菌和真菌降解过程中的生物化学和生理学特性,以及结构因素对聚乙烯醇生物降解的影响。这些研究促进了可有效生物降解的PVA类材料产品项目的发展。     

聚乳酸的生物降解

聚乳酸(polylactic acid, PLA)因其良好的理化性能、生物相容性和生物降解性而备受关注，已被认为是石油基塑料最具潜力的替代者，但在实际应用中仍然存在降解缓慢循环周期长的问题，因此对PLA的生物降解深入研究对于解决塑料垃圾污染和缓解能源危机至关重要。近年来，有关微生物(放线菌、细菌和真菌)和酶(蛋白酶、脂肪酶、酯酶和角质酶)降解PLA的研究已经取得了一定的进展。本文从降解微生物、降解酶和降解机制等方面综述了PLA生物降解的研究进展，并展望了PLA生物降解研究未来的发展趋势。     

Alternative methods for determining anaerobic biodegradability: A review

The characterization of solid wastes is a necessary step before they can be used in anaerobic digestion. The quantities of different compounds (carbohydrates, proteins, lipids and fibers) and anaerobic biodegradability (capacity to produce methane) are important information required to characterize waste. The Biochemical Methane Potential (BMP) test is one of the most relevant tests for assessing the biodegradability of waste materials. The BMP test is run under anaerobic conditions, using bacteria populations, which makes it very time consuming, i.e., about 30 days. This paper presents alternative methods for determining the anaerobic biodegradability of solid waste. First, we describe the already existing tests for characterizing organic matter. Then we correlate an aerobic test with an anaerobic test in order to estimate anaerobic biodegradability and biogas production. This shortens the analysis time to 5 days. Models using physico-chemical characteristics as input data (total carbohydrate, total nitrogen, fiber, etc.) can predict the amount of methane produced by correlation. Pyrolysis is a very fast analytical test that can be used to characterize solid waste. Lastly, spectroscopy techniques seem to be useful for determining biodegradability, in particular by taking into account the interaction between different molecules in the organic matter.     

植物挥发性气体(VOCs)研究进展

植物挥发性气体(VOCs)在植物一植食性昆虫-天敌三级营养关系、植物间信息传递及适应性改变上都发挥着重要作用.植物释放VOCs具特异性、系统性、时序性与节律性等特点,VOCs主要在寄主选择行为、产卵行为、求偶行为、引来昆虫夭敌干涉等方面影响植食性昆虫.VOCs-介导的植物间信息传递作用包括4个过程:"释放者"植物合成及释放气体、气体在空气中的运输、气体在植物表面的吸附及"接收者"植株对气体信号的感知.收集VOCs的方法主要有吸附-溶剂洗脱法和吸附-热脱附法.     

Prediction of biodegradability for selected organic chemicals

Summary The 5-day BODs of 45 organic chemicals were determined using acclimated mixed microbial cultures. These chemicals included alcohols, acids, esters, ketones, aromatics and miscellaneous compounds. The BOD data were correlated with (1) water solubilities, (2) log of 1-octanol/water partition coefficients, (3) molar refractivities and volumes, (4) melting (m.p.) and boiling points, (5) number of carbon (C No.), hydrogen and oxygen atoms, (6) molecular weights, and (7) theoretical (Th) BODs of chemicals. Linear and secondorder polynomial regression analyses were used; the latter was also attempted with two or more independent variables. All prediction equations were compared for statistical merits. The equations, one from each regression type, with the highest prediction power were: log 5-day mmol BOD/mmol chemical=(1)–0.183+0.813 (log ThBOD), (2)–0.391+1.560 (log ThBOD) –0.532 (log ThBOD)², and (3) –0.4060+0.2470 (C No.) –0.0133 (C No.)²–0.0005 (m.p.). The measured BOD data for 43 additional chemicals were compared with the predicted values calculated through the above equations. The three equations predicted the BODs for 84–88% of the test chemicals within 80% of the experimental values. The mean percent relative standard deviations between predicted and experimental BOD values were statistically compared for these equations, and no significant difference (P0.01) in their predictive utility was found. The acclimation potential of an autochthonous microbial community cannot yet be predicted, but this study demonstrates that the process of active biodegradation for structurally dissimilar chemicals appears to correlate quantitatively with certain physicochemical parameters.     

A comprehensive review of the screening methodology for anaerobic biodegradability of surfactants

A biodegradability assay should mimic in situ conditions as closely as possible. If this is not entirely possible, the assayshould at least include inoculum from the site. This review attemptsto condense current literature on anaerobic biodegradability assayand propose a clear assessment methodology to determine the fatesurfactants in anaerobic environments. It has been well documentedthat surfactant concentrations toxic to the microflora can lead tounwarranted failure of biodegradability assays. Thus, an important recommendation is to first perform a toxicity evaluation with relevant controls. Based on the results of this evaluation, a Tier 1biodegradability assay that assesses the rate of formation of reducedendproducts or the consumption of a particular terminal electron acceptor is recommended and supported by current literature. Balancedchemical equations for the complete mineralization of the substrateare then used to compare the amount of transformation that actuallyoccurred with that theoretically expected. When required, resultsshould be confirmed by Tier 2 testing, which includes monitoring ofsubstrate disappearance over time using a variety of analytical tools.These recommended procedures are scientifically defensible and havethe potential of providing environmentally relevant information on thefate of surfactant materials in the environment.     

A critical comparative assessment of predictions of protein-binding sites for biologically relevant organic compounds

Protein function annotation and rational drug discovery rely on the knowledge of binding sites for small organic compounds, and yet the quality of existing binding site predictors was never systematically evaluated. We assess predictions of ten representative geometry-, energy-, threading-, and consensus-based methods on a new benchmark data set that considers apo and holo protein structures with multiple binding sites for biologically relevant ligands. Statistical tests show that threading-based Findsite outperforms other predictors when its templates have high similarity with the input protein. However, Findsite is equivalent or inferior to some geometry-, energy-, and consensus-based methods when the similarity is lower. We demonstrate that geometry-, energy-, and consensus-based predictors benefit from the usage of holo structures and that the top four methods, Findsite, Q-SiteFinder, ConCavity, and MetaPocket, perform better for larger binding sites. Predictions from these four methods are complementary, and our simple meta-predictor improves over the best single predictor.     

Fungal volatile organic compounds: A review with emphasis on their biotechnological potential

Fungi produce various mixtures of gas-phase, carbon-based compounds called volatile organic compounds (VOCs) that due to their small size are able to diffuse through the atmosphere and soils. Despite some methodological and technological constraints, researchers have detected and characterized approximately 250 fungal VOCs, many of which have characteristic odors and are produced during primary and secondary metabolism. Fungal VOCs may contribute to a controversial medical diagnosis called “sick building syndrome” and may also be important in the success of some biocontrol species of Trichoderma. VOCs also play important signaling roles for fungi in their natural environments. Many ecological interactions are mediated by VOCs, including those between fungi and plants, arthropods, bacteria, and other fungi. The diverse functions of fungal VOCs can be developed for use in biotechnological applications for biofuel, biocontrol, and mycofumigation. Volatiles represent a new frontier in bioprospecting, and the study of these gas-phase compounds promises the discovery of new products for human exploitation and will generate new hypotheses in fundamental biology.     

Screening test for assessment of ultimate biodegradability: linear alkylbenzene sulfonates.

A relatively simple shake-flask system for determining CO2 evolution was developed to assess the ultimate biodegradability by soil and sewage micro-organisms of chemicals which enter the environment. Linear alkylbenzene sulfonates (LAS) were used as model compounds to evaluate the method and were found to undergo substantial biodegradation in this dilute system. At the 30 mg/liter test concentration, higher-molecular-weight LAS compounds were biodegraded at a slower rate and to a lesser extent than lower-molecular-weight LAS, an effect which was eliminated or greatly reduced upon incremental addition of the LAS to the test medium during the first week of incubation. LA35S was used to demonstrate rapid LAS desulfonation, and 14CO2 evolution studies with (14C) benzene ring-labeled LAS indicated concomitant biodegradation of the entire LAS molecule as well as the LAS aromatic component. The test can be employed to examine numerous compounds at the same time and is readily adapted to studies of the effect of variation in temperature and oxygen concentration on biodegradation.     

Comparison of two extraction procedures for the assessment of sediment genotoxicity: implication of polar organic compounds

Four sediment samples (Va?ne Airport VA, Va?ne Center VC, Va?ne North VN and Reference North RN) were collected in the Berre lagoon (France). Sediments were analyzed for polycyclic aromatic hydrocarbons (PAHs) by use of pressurized fluid extraction with a mixture of hexane/dichloromethane followed by HPLC with fluorescence detection analysis. Organic pollutants were also extracted with two solvents for subsequent evaluation of their genotoxicity: a hexane/dichloromethane mixture intended to select non-polar compounds such as PAHs, and 2-propanol intended to select polar contaminants. Sediment extracts were assessed by the Salmonella/microsome mutagenicity test with Salmonella typhimurium TA98+S9 mix and YG1041±S9 mix. Extracts were also assessed for their DNA-damaging activity and their clastogenic/aneugenic properties by the comet assay and the micronucleus test with Chinese Hamster ovary (CHO) cells. The PAH concentrations were 611ngg(-1)dw, 1341ngg(-1) dw, 613ngg(-1)dw and 482ngg(-1)dw for VA, VC, VN and RN, respectively. Two genotoxic profiles were observed, depending on the extraction procedure. All the non-polar extracts were mutagenic for TA98+S9 mix, and VA, VC, VN sediment samples exerted a significant DNA-damaging and clastogenic activity in the presence of S9 mix. All the polar extracts appeared mutagenic for TA98+S9 mix and YG104±S9 mix, and VA, VC, VN were genotoxic and clastogenic both with and without S9 mix. These results indicate that the genotoxic and mutagenic activities mainly originated from PAHs in the non-polar extracts, while these activities came from other genotoxic contaminants, such as aromatic amines and nitroarenes, in the polar extracts. This study focused on the important role of uncharacterized polar contaminants such as nitro-PAHs or aromatic amines in the global mutagenicity of sediments. The necessity to use appropriate extraction solvents to accurately evaluate the genotoxic hazard of aquatic sediments is also highlighted.     

微卫星位点获取方法的研究进展

微卫星标记(simple sequence repeat,SSR)是进行分子遗传学研究的一种有效手段,并以其多态性高、信息含量大、保守性等特点成为最受人们欢迎的分子标记之一.但微卫星标记具有种族特异性,必须采用特异引物进行PCR检测,因而存在引物开发的问题.本文就筛选基因组文库法、微卫星富集法、数据库查找法、近缘物种筛选法、TOMMI法和FI-ASCO法等具有代表性的微卫星标记开发策略进行了综述,旨在为分子生态学研究过程中微卫星位点筛选方法的选择提供参考.