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1.
微生物降解苯胺的特性及其降解代谢途径   总被引:7,自引:0,他引:7  
从活性污泥中分离得到的一株细菌 A N3 ,能以苯胺为唯一碳、氮源和能源生长,苯胺的最高降解浓度5000 mg/ L 以上,鉴定为食酸丛毛单胞菌( Comamonas acidovorans) . A N3 还可降解乙酰苯胺,但不利用其他取代类苯胺,该菌株的生长细胞和完整细胞降解苯胺的最适p H7 .0 ,最适温度30 ℃,且完整细胞降解苯胺的活性比生长细胞高得多.9 种金属离子对该菌株的生长细胞和完整细胞降解苯胺均有不同程度的抑制作用,尤以 Ag + 和 Hg2 + 为明显. A N3 含有苯胺加双氧酶、邻苯二酚2 ,3加双氧酶等一系列与苯胺降解有关的酶类,它们均为诱导酶.对苯胺降解的关键酶进行了酶动力学特性的研究,根据这些结果提出了该菌株降解苯胺的代谢途径.  相似文献   

2.
原生质体转化构建有机磷农药降解工程菌   总被引:5,自引:0,他引:5  
降解有机磷农药甲胺磷、敌敌畏和对硫磷的菌株地衣芽孢杆菌 P12( Bacilluslicheniformis) 经溶菌酶处理获得原生质体,加入降解乐果的供体菌 G1 D N A,经ρ( P E G6 000) = 300 g L- 1 诱导,在液体再生培养基中振荡培养t= 20 h ,使其恢复细胞壁后,离心收集菌体,涂布于含乐果的基础培养基上,经筛选得一转化子 J P Z.其菌落形态明显不同于出发菌株,乐果平板连续传代10 次,性状保持稳定.在θ= 30 ℃,100 r/min 的培养条件下,3 d 内对ρ( 甲胺磷) = 0 .5 g L- 1 ,ρ( 敌敌畏) = 0 .2 g L- 1 ,ρ( 对硫磷) = 0 .1 g L- 1 ,ρ( 乐果) = 0 .3 g L- 1 的降解率分别为 Rd = 79 .1 % ,46 .7 % ,29 .4 % 和46 .4 % .  相似文献   

3.
从土样中筛选得到20支可将富马酸转化为L-苹果酸垢细菌菌株。经摇瓶复筛,得到一株富马酸酶活力较高的ZG-4菌株。以改性PVA为载体,制备得到固定化细胞。其较佳转化条件为:1经mol/L Na2Fu为底物,pH7.0,40转化。固定化细胞经胆酸ρ=4g/L或TPCρ=0.6g/L预处理后,可有效抑制琥铂酸副产物的生成。添加没食子单宁ρ=1gL,可使富马酸酶比活力达1.95mmol g^-h^-。固定  相似文献   

4.
LHG1菌株的分离和降解环己烷的研究   总被引:9,自引:0,他引:9  
通过选择性培养从石油废水污染的土壤中分离出一株以环己烷为唯一碳源和能源的降解菌株 L H G1 ,对 L H G1 菌株的降解特性进行了研究.确定 L H G1 菌株最适培养条件为:培养时间60 ~100 h 、环己烷浓度460 ~770 mg/ L、p H6 ~8 、ρ( Na Cl) = 10 g L- 1 、θ= 25 ~40 ℃. L H G1 菌株能够利用环烷烃代谢的中间产物环己酮和环戊酮.此外, L H G1 菌株还能降解液体石蜡、固体石蜡、萘和苯酚等链烃、芳香烃和酚类  相似文献   

5.
农药降解酶的固定化及其降解特性   总被引:11,自引:0,他引:11  
采用海藻酸钙凝胶将 Alcaligenes sp . Y F11 农药降解酶进行固定化,并测定了固定化酶对杀灭菊酯的降解特性. 农药降解酶的固定化条件为:海藻酸钠质量浓度,30 g/ L;蛋白质量浓度,0 .2 g/ L;固定化时间t = 16h ;粒径4 mm . 固定化酶降解杀灭菊酯的最适p H 为8 .0 、最适温度为35 ℃, Km55 .0 μmol/ L  相似文献   

6.
微生物降解蔬菜残留农药研究   总被引:36,自引:2,他引:34  
从富集培养物中筛选到以甲胺磷为唯一碳源生长的菌株NMJ5和以乐果为唯一碳源生长的菌株NML3,经鉴定分别为芽孢杆菌属(Bacilussp.)和假单胞菌属(Pseudomonassp.).它们利用甲胺磷、乐果生长的最适条件及在无机盐培养基中农药最大耐受浓度分别为pH7.5,t=35℃,ρ=1000mg/L和pH7.5,t=30℃,ρ=2000mg/L.在无碳基础培养基内单菌株培养8d,524mg/L的甲胺磷好气降解42.5%,厌气降解35.9%,250mg/L的乐果好气降解50.2%,厌气降解16.4%.小区试验表明,NMJ5、NML3的菌液制剂对普通白菜的变种南农矮脚黄(Brasicacampestrissp.chinensisL.var.communisTsenetLee)中残留的甲胺磷、乐果有明显的去除作用.  相似文献   

7.
一株高浓度苯胺降解菌的分离   总被引:7,自引:0,他引:7  
通过驯化培养,从含苯胺的化工废水处理厂生化曝气池污泥中分离出一株高效苯胺降解菌 H62 ,在苯胺浓度低于3 000 mg/ L 的无机盐培养基中均可生长. H62 利用苯胺的最适温度为30 ℃,最适p H 为8 .0 ,当苯胺浓度在600 mg/ L 以下时,对该菌不表现出明显抑制作用.在含苯胺800 mg/ L 的无机盐溶液中,通气量为0 .4 L/min ,30 ℃,培养15 小时可使苯胺去除率达100 % .经鉴定,该菌株为不动杆菌属( Acinetobactersp .) .  相似文献   

8.
蔓茎堇菜细胞悬浮培养的研究   总被引:5,自引:0,他引:5  
对蔓茎堇菜细胞悬浮培养的条件进行了选择,并测定悬浮培养的生长动态。结果表明:蔓茎堇菜细胞悬浮培养的最适接种量为2.0~3.5g(50mL);最适培养基为MS+2.0mg/L2,4-D+1.0mg/L ZT+300mg/L LH+200g/L蔗糖(或葡萄糖),pH5.8;细胞悬浮培养一个周期过程中细胞数目增长的动态基本上是一条S型曲线,对数生长期明显;细胞鲜重(mFW)和细胞干重(mDW)则与细胞  相似文献   

9.
用从土壤中筛选的假单胞菌(Pseudomonassp.)E4106株细胞进行了转化苯丙酮酸生产L苯丙氨酸实验研究.结果表明,转氨反应最适温度35~40℃;该转氨酶可在pH7~10范围内催化反应而活力变化不大;0.5%戊二醛处理细胞可降低其转氨酶活力;表面活性剂处理细胞或在反应液中加入Mg2+能显著提高转氨反应速度;L天冬氨酸是转氨反应的最适氨基供体;底物转化率与底物浓度、氨基供体浓度有关.在此反应体系中,E4106菌株单位湿重细胞的转氨酶活力为1039U/g;生成产物LPhe浓度为32.2g/L和50.4g/L时,苯丙酮酸摩尔转化率分别为97.5%、87.2%.生成产物用CGA688大孔吸附树脂进行分离、纯化.目标产物经熔点、比旋光度、元素分析、红外光谱和纸层析分析,证实是LPhe.产物收率为81.8%.  相似文献   

10.
啤酒酵母吸附Cu^2+的模拟实验   总被引:17,自引:0,他引:17  
研究了啤酒酵母吸附重金属Cu2+离子的可行性及反应条件对去除作用的影响.结果表明:用啤酒酵母处理Cu2+,在起始浓度ρ0为20~400mg/L的范围内,吸附量w为2.98~12.03mg/g,说明用啤酒酵母去除重金属Cu2+是可行的.吸附反应在10~20min基本达到吸附平衡.最适反应温度(θ)和pH分别为15~20℃和4.0~6.0,酵母细胞有一最适投加用量.Freundlich吸附等温方程的分析表明,η与重金属离子种类有关,与酵母细胞种类关系较小;k值与酵母种类和重金属离子种类有关.  相似文献   

11.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

12.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

13.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

14.
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  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

17.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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