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1.
在不同温度和不同光照条件下对3株金龟子绿僵菌和1株贵州绿僵菌的液体深层培养研究表明,光照对菌丝生长和液生分生孢子产量均无显著影响。但培养温度显著影响菌丝生长和液生分生孢子的产出率,25-28℃为液体深层培养绿僵菌的适宜温度,其中以28℃最佳,对3-4龄马尾松毛虫幼虫的室内毒力测定表明,绿僵菌液生分生孢子的毒力略低于气生分生孢子。  相似文献   

2.
绿僵菌降解寄主表皮的蛋白酶同工酶研究   总被引:4,自引:0,他引:4  
研究了不同碳氮源对金龟子绿僵菌( Metarhizium anisopliae) 产生与分解昆虫外壳相关的蛋白酶活性和同工酶谱带的影响. 结果表明:蝉蜕、虻虫壳、蝇蛆壳、蚕蛹壳、虾壳、胶体几丁质均可使金龟子绿僵菌产生蛋白酶,虾壳和胶体几丁质所产生的蛋白酶比活性最高,蝉蜕次之. 但蛋白酶总活性以蝉蜕最高,虻虫壳次之.样品经等电聚焦电泳后,印迹于X光片上,显示蛋白酶同工酶,蝉蜕和蚕蛹壳产生的蛋白酶同工酶谱带最丰富. 以蝉蜕为唯一碳氮源时,金龟子绿僵菌产生蛋白酶的最佳条件为26℃、初始pH6.0 、最终孢子浓度n= 1×107mL-1 .  相似文献   

3.
一株能分解纤维素的高温耐碱放线菌   总被引:22,自引:0,他引:22  
对一株分离于堆肥的分解纤维素的放线菌的形态学和生理生化特征进行了研究.结果表明:基丝由分枝发达的不断裂的菌丝组成,气丝发达;孢子单个长在气丝上,孢子表面光滑,细胞壁含meso-DAP;该菌能分解纤维素,液化明胶、水解酪素和淀粉,在35-60℃生长,pH范围为6.0—12.0.按《伯杰氏系统细菌学鉴定手册》进行了鉴定,初步将此菌归为高温单孢菌属(Thermomonospora sp.)的一个新种.研究了产羧甲基纤维素酶(CMCase)和滤纸酶(FPA)的条件.CMCase最适产酶时间为5d,FPA为8d,最适产酶温度为50℃,产酶最适起始pH为9.5—10.5.最适氮源为黄豆粉,最佳碳源为棉花纤维.图6表2参10  相似文献   

4.
对一株内生真菌韦司梅拟盘多毛孢(Pestalotiopsis vismiae)的培养条件进行探究,在此基础上进一步对其发酵提取物抗氧化、抗菌活性进行分析.通过测定菌丝的生长速度寻找菌丝培养适宜的温度、碳源、氮源和pH,并采用正交试验优化培养条件;通过测定菌株深层发酵液提取物对羟基和DPPH自由基的清除率以分析其抗氧化活性;通过测定菌株深层发酵液提取物对多种病原细菌抑菌圈大小的影响来分析其抗菌活性.结果表明,韦司梅拟盘多毛孢菌丝最适宜培养温度为25℃,在该温度培养条件下菌丝生长最佳碳源为蔗糖,最佳氮源为酵母提取粉,最佳初始pH为6.5,这3种因素的显著性差异大小顺序为碳源氮源 pH;菌株深层发酵液提取物具有良好的抗氧化活性,其对羟基自由基和DPPH自由基清除率的EC50分别为1.19 mg/mL和0.56 mg/mL;菌株发酵液提取物对铜绿假单胞杆菌、金黄色葡萄球菌均具有一定的抑制作用;深层发酵液提取物抗氧化和抗菌活性具有一定的稳定性.本研究结果可为深入开发利用该真菌资源提供科学依据.(图12表3参26)  相似文献   

5.
为探讨贵州省福泉市葡萄灰霉病的流行机制与防治研究,对该地区病害的病原菌进行鉴定和生物学特性.从葡萄灰霉病样品中分离纯化了多个病原菌菌株,并进行了形态特征观察和多基因系统发育树分析;选择代表性菌株GZFQ-1进行葡萄的茎、叶片和果实的致病性分析;同时,对GZFQ-1菌株在不同温度、pH条件下的生长情况及对不同碳源和氮源的利用进行研究.根据病原菌的形态学和分子特征,将贵州省福泉市葡萄灰霉病菌鉴定为灰葡萄孢菌(Botrytis cinerea).该菌株在PDA培养基上生长的最适温度是25℃,其次为22℃;在pH值为5-9的范围内,该菌株均可生长,且在pH值5-8范围内,生长相对较快;以葡萄糖为碳源,以硝酸钾、蛋白胨、组氨酸和异亮氨酸为氮源时,利于菌丝发育,同时,碳、氮源也会影响菌株的生长速率和色素形成.综上所述,发生在贵州省福泉市葡萄灰霉病的病原菌为B.cinerea,且能够引起嫩茎、叶和果实发病,这一结论可为该地区葡萄灰霉病的有效防治提供理论指导.(图6表2参32)  相似文献   

6.
为明确鸭茅真小孢帽菌(Eutiarosporella dactylidis)生物学特性及主栽玉米品种对其引起的叶枯病的田间抗病能力,从碳氮源、酸碱度及生长温度等方面对该病菌的生物学特性进行研究,并通过人工接种的方法对甘肃中部产区12个主栽玉米品种抗性进行分析评价.结果表明,该病菌的菌丝生长最适温度为25℃,形成分生孢子器的最适温度范围为15-25℃;菌落可在pH 4.0-12.0的培养基上生长,在pH 6.0时,菌落生长速度最快,偏酸条件有利于分生孢子器的形成;营养生长最适碳源和氮源分别为葡萄糖和酵母浸膏,氮源对产生分生孢子器的数量影响较显著,而碳源对其影响不显著;PDA和PSA有利于菌丝体生长和分生孢子器形成;14 h光照+10 h黑暗交替条件有利于菌丝扩展,而24 h紫外线有利于形成分生孢子器. 12个供试玉米栽培品种对该病菌引起的叶枯病的抗性存在差异,病情指数为16.05-83.82;其中1个品种(登义2号)表现抗病(R),1个品种(诚信1号)表现中抗(MR),分别占8.33%;其余10个品种均表现感病(S),占83.33%.本研究表明鸭茅真小孢帽菌环境适应性广,生产上缺少抗病品...  相似文献   

7.
蓝藻发酵生产微生物农药的影响因素研究   总被引:3,自引:0,他引:3  
采用摇瓶发酵试验探讨了蓝藻为原料制备苏云金杆菌生物杀虫剂的可行性,并考察了不同培养条件(蓝藻含固率、种龄、接种量、初始pH、摇床转速、发酵温度)对苏云金杆菌生长增殖、产孢与产毒效果的影响。研究结果表明,无需任何预处理工序,Btk 130菌株能在蓝藻为唯一原料的培养基中正常生长发育,并且产孢产毒。发酵48 h后,芽孢产率达到86.7%,远高于常规培养基;生物毒效为282 IU.mL-1,与常规培养基相当。培养条件优化结果表明,在蓝藻含固率为2%、初始pH为7.0、接种物种龄为9 h、接种量为2%、培养温度为30℃、摇瓶转速为200 r.min-1的条件下培养48 h,Btk 130可达到较好的发酵效果,活菌数及抗热芽孢数可达7.32 CFU.mL-1和6.38 CFU.mL-1,生物毒效为528 IU.mL-1。该研究不仅为蓝藻提供了高附加值的处置新途径,而且可显著降低生物杀虫剂的生产成本,具有广阔的应用前景。  相似文献   

8.
为了选育高产纤维素酶菌株,通过刚果红鉴别培养基以及滤纸条崩解实验测定,从牛粪堆肥中筛选到一株产纤维素酶的真菌HS-F9,根据菌株形态特性和18SrRNA基因序列分析,初步鉴定该菌为绿色木霉(Trichoderma viride).利用液体发酵培养产生纤维素酶,研究了碳源、氮源、培养时间、培养温度、培养基起始pH、接种量对菌株HS-F9产酶的影响.结果表明:产EG、CBH和FPA的最适碳源均为CMC-Na;EG和CBH在以蛋白胨为唯一氮源时酶活最高,FPase则在以黄豆粉为唯一氮源时酶活最高;产生EG、CBH和FPA的最适温度分别为30℃、30℃、33℃;最适起始pH为3.0、3.0和4.0;EG和FPase的最适接种量为2%,CBH最适接种量达到了8%;培养时间均以5~6d为宜.在最适条件下培养,该菌株EG、CBH和FPase的酶活分别达到了5275.3U/mL、8502.1U/mL和3619.1U/mL,是未优化前的1.42、1.35和1.32倍.图6表2参23  相似文献   

9.
漂白废水白腐菌脱色的条件   总被引:5,自引:1,他引:4  
碳源、氮源、Mn^2 浓度及pH值对F7菌漂白废水脱色有较大的影响,最佳培养基组成为:ρ(葡萄糖)10g/L,ρ(NH4Cl)0.13g/L,ρ(Mn^2 )20mg/L,随葡萄糖和NH4Cl添国量的增加,菌体生物量增加,但高浓度的NH4Cl对F7菌脱色有抑制作用,F7菌适宜生长pH值为4-5,适宜脱色pHwfhgo 3-6,最适脱色pH值为5.0另外,经脱色处理的漂白废水的毒性明显下降。  相似文献   

10.
光合细菌对铜绿微囊藻生长的抑制效应   总被引:2,自引:0,他引:2  
为了探讨光合细菌对水华藻类的控制作用,在实验室条件下,通过菌藻共同培养,研究了沼泽红假单孢菌(Rhodopseudomonas palustras)、球形红细菌(Rhodobacter sphaeroides)及其混合培养物对铜绿微囊藻(Microcystis aeruginosa)生长的抑制效应.实验结果表明,光合细菌混合培养物对铜绿微囊藻抑藻作用最强,培养5 d时,铜绿微囊藻生物量降低率达58.9%,培养时间、培养温度、菌体投加量及培养基pH值等对光合细菌混合培养物的抑藻作用均有不同程度的影响.光合细菌混合培养物发挥抑藻作用的适宜条件为培养温度25℃,培养时间≤5 d,光合细菌投加量(V_(光合细菌菌悬液):V_(藻培养液)=1:80),藻培养基pH为8.0左右.  相似文献   

11.
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   

12.
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   

13.
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   

14.
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.  相似文献   

15.
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   

16.
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.  相似文献   

17.
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.  相似文献   

18.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

19.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

20.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

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