蜡状芽孢杆菌HY-1降解甲基对硫磷和毒死蜱的影响因素研究

采用富集驯化培养和紫外分光光度计定量的方法,从农药生产企业的废水处理系统中分离筛选出1株能够降解甲基对硫磷和毒死蜱的蜡状芽孢杆菌（Bacilluscereus）HY-1,并系统研究了影响其降解甲基对硫磷和毒死蜱的主要因素。研究表明,菌株HY-1能够利用甲基对硫磷和毒死蜱为唯一磷源降解农药。HY-1降解甲基对硫磷的适宜条件为：培养温度30～35℃,pH为6～8,甲基对硫磷初始浓度为10～50mg·L^-1,接种量20%（体积比,菌体密度：稀释到菌悬母液（OD600=3.0）的0.8～1倍）,添加葡萄糖不能促进菌株对甲基对硫磷的降解。HY-1降解毒死蜱的适宜条件为：葡萄糖浓度6g·L^-1,培养温度30～35℃,pH为7.0,毒死蜱初始浓度80～200mg·L^-1,接种量20%（体积比,菌体密度：稀释到菌悬母液（OD600=3.0）的0.8～1倍）。结果表明,HY-1菌株降解甲基对硫磷和毒死蜱的适宜条件相类似,只是降解所需的最适葡萄糖浓度和底物浓度不同。     

阴离子交换树脂固定化果胶酶及其酶学性质的研究

以阴离子交换树脂为载体,戊二醛为交联剂,对果胶酶进行先吸附后交联的固定化,研究吸附温度、吸附pH值、吸附时间、加酶量、戊二醛浓度、交联温度、交联时间对果胶酶固定化效果的影响,同时对固定化果胶酶的特性进行了研究。研究表明,最佳固定化条件为:温度40°C,pH 5.5,固定化6 h,加酶量0.75 mL/g树脂(浓度为1%酶液),戊二醛交联浓度0.1%,交联温度4°C,交联时间4 h。酶学特性研究表明,固定化果胶酶在最适温度60°C,最适pH 4.0下具有较好的操作稳定性。     

家蚕丝素固定化过氧化氢酶的制备及其理化特性的研究

脱胶丝素于ＣａＣＩ２：ＣＨ２ＯＨ：Ｈ２Ｏ＝１：２：８（摩尔浓度比）溶液中溶解、透析除盐后,加入过氧化氢酶溶液,摇匀,用硫酸铵盐析,用包埋法制成粉状固定化酶采用磺量法测定酶活力。实验结果表明：固定化制备过程中,硫酸铵浓度以４５％为好,酶量达到１５０Ｕ／ｍＬ时,固定化酶的酶活力达到最大值。实验比较了游离酶和豁达一化酶的最适ＰＨ值和最适温度后显示,因经酶的最适ＰＨ降低了０．８,最适温度提高了约１０℃,另     

胰蛋白酶对壳聚糖的降解研究

用粘度法和吸光度法，研究胰蛋白酶非专一性降解壳聚糖过程中温度、PH值、反应时间、酶浓度、底物浓度。金属离子对胰蛋白酶降解壳聚糖反应的影响，确定了以壳聚糖为底物的胰蛋白酶的一些催化特性：最适温度为30℃，最适PH值为5.0,10-180min内酶反应速度恒定，酶浓度在0.1-0.5g/L的范围内，酶反应速度与酶浓度呈线性关系，米氏常数Km为9.54g/L。     

甲基对硫磷降解菌的生态效应及应用

从活性污泥中分离的甲基对硫磷降解菌接种于含有甲基对硫磷的土壤中，表现了较强的降解农药残留的生态效应。在盆栽试验中，处理的各叶片变黄程度比对照均要轻，统计差异显著，稻米与稻壳中甲基对硫磷处理比对照下降了８２．２－１００％。田间试验中，农药加菌，农药加有机肥加菌的处理，其稻米中的甲基对硫磷残留均检测不到，而对照（只施农药不加菌），稻米中的甲基对硫磷含量为０．０６５ｍｇ／ｋｇ，超过国家标准（０．０５ｍｇ     

甲基对硫磷降解菌DLL-1的诱变育种

采用紫外线和氯化锂诱变 ,从甲基对硫磷降解菌假单胞菌 (Pseudomonassp.)DLL -1中获取高效突变株DLL -E1 ,DLL -E2 ,DLL -E3 ,DLL -E4。并对其降解甲基对硫磷性能、降解对硝基苯酚性能、底物广谱性及胞外酶及粗酶液活性等生物学功能进行了研究。与出发菌株相比 ,上述性能均有所提高。选择DLL -E4作为进一步研究的对象 ,详细研究了其对甲基对硫磷及对硝基苯酚的耐受和降解情况。高效菌株的选育为农药残留降解的酶学研究打下了基础。     

竹炭固定化微生物对土壤中阿特拉津的降解研究

采用环境友好材料竹炭为主要载体,壳聚糖和海藻酸钠为辅助载体,固定从污泥中分离出的阿特拉津降解菌株,研究不同固定材料对降解菌生长的影响,以及固定化微生物对土壤中阿特拉津的降解效果.结果表明,竹炭对阿特拉津降解菌具有较强的吸附固定能力,且竹炭粒径越小,固定化效果越好.利用壳聚糖和海藻酸钠交联并加固阿特拉津降解菌,增大了固定化空间,显著增加了降解菌的生物量,并提高了阿特拉津的降解效率.1％壳聚糖+5％海藻酸钠+竹炭+降解菌颗粒对阿特拉津降解菌的固定化效果最佳,施用该微生物固定化颗粒28天后,砂姜黑土及红壤中阿特拉津残留率分别为48.07％和47.23％.     

检测有机磷农药残留生物传感器的温度特性

为了考察检测有机磷农药残留用量热式生物传感器的温度特性,本文采用分光光度法研究了固定化鸡肝酯酶的活力、农药敌敌畏对鸡肝酯酶的抑制等与温度的关系。在生物传感器的实测条件下,研究了不同温度固定化酶活力的操作流失情况。研究显示,温度对酶反应的影响很大,控温精度的提高将增强检测的精度和稳定性。温度55～60℃时,是酶反应速度最快的区域;抑制时间5 min时,农药敌敌畏对鸡肝脂酶产生了明显的抑制作用。在农药浓度小于1 mg/L的区域,随浓度变化的相对抑制关系接近于线性;一定浓度的农药敌敌畏对酶的抑制程度随着温度的变     

阿维菌素降解菌株AW70的分离鉴定及降解特性研究

从长期受阿维菌素农药污染的土壤中分离到一株能高效降解阿维菌素的菌株AW70.结合生理生化实验和16S rDNA序列同源性分析,将该菌株鉴定为伯克霍尔德氏菌属(Burkholderia sp.),Gen Bank登录号为EU295449.菌株AW70能利用阿维菌素为唯一C源生长,在温度25℃～ 42℃和pH 6.5 ～ 8.5 范围时降解能力较好,其最适降解温度为30℃,最适初始pH值为7.48 h对50 mg/kg阿维菌素的降解率大于85%.南丰蜜桔上农药降解试验结果表明,喷施菌株AW70菌剂的蜜桔中未检测到阿维菌素的残留,表明该菌株具有良好的应用前景.     

纳米磁酶水酶法在磁流化床中提取大豆油脂的数值模拟及应用

为提高大豆油的提取率以及油的品质，该研究将游离纤维素酶固定在磁性高分子载体Fe3O4/SiOx-g-P（GMA）上，利用数值模拟确定磁流化床中水酶法提油的最佳参数，并将最佳参数应用在磁流化床中，通过单因素试验探究磁性固定化纤维素酶在磁流化床中水酶法提油的最佳工艺条件。结果表明：扫描电镜、粒径分析和红外光谱显示磁性固定化纤维素酶已固定在磁性高分子载体Fe3O4/SiOx-g-P（GMA）上，且具有较好的磁响应能力，与游离酶相比，磁性固定化纤维素酶提高了酶的耐热性和耐酸碱性。数值模拟得出磁场强度为0.034 T，流速为0.004 1 m/s时，磁酶在磁流化床中可与大豆料液充分接触，有利于提高大豆油提取率。磁流化床中水酶法提油较优工艺为：酶添加量为1.2 mg/g，pH值为5，温度为55 ℃，反应时间120 min，此时大豆油提取率较优为90.3%。磁性固定化纤维素酶在磁流化床中可以连续使用12 h。该研究提高了大豆油提取率，与间歇反应相比，磁流化床大豆油提取率增加了6.1%。研究结果为后续磁流化床水酶法提油提供了理论依据。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.