共查询到20条相似文献，搜索用时 15 毫秒
1.
[目的]从薄皮甜瓜体表分离筛选对引起薄皮甜瓜采后病害主要病原真菌具有拮抗作用的生防菌株,并对其进行鉴定确定分类地位,为薄皮甜瓜采后病害的防治提供高效菌株.[方法]采用活体生测的方法从甜瓜瓜表筛选生防菌株,利用非寄养非肠道革兰氏阴性杆菌鉴定试剂盒（比色法）API 20 NE自动鉴定系统测定菌株C3的生理生化指标.[结果]从甜瓜表面分离筛选出2株对粉红单端孢（Trichothecium roseum）防治效果达80％以上的生防菌株C3、B3;通过平板对峙试验表明,菌株C3对引起采后病害的2种病原菌粉红单端孢（Trichothecium roseum）和镰刀菌（Fusarium spp.）的抑菌能力均优于B3;菌株C3对粉红单端孢（Trichothecium roseum）的抑菌效果较好,达到67.7％;对镰刀菌（Fusarium spp.）的抑菌率次之,为27.9％;应用API 20 NE系统分析,通过形态学观察、革兰氏染色将菌株C3初步鉴定为浅黄假单胞菌Pseudomonas luteola.[结论]从甜瓜表面分离筛选获得1株生防菌株C3,该菌株对引起薄皮甜瓜采摘后病害的主要病原菌粉红单端孢（Trichothecium roseum）具有较强的拮抗作用,并初步鉴定为浅黄假单胞菌（Pseudomonas luteola）. 相似文献
2.
从浙江农业大学华家池实验农场连作早、晚稻的土中,分离到五株优势的产甲烷细菌菌株.其中的8901,8902和8903菌株为杆状,能利用H_2/CO_2和甲酸,8901和8902菌株还能利用异丙醇为生长和产甲烷的基质,它们的最适生长温度为40℃,与栖息环境温度不相一致,其最适生长pH为7.0～7.5.8904和8905菌株为八叠球菌形,首次报道了8904菌株细胞表面具有花生壳网纹状结构,此外,分离到的五株菌株未检测出具有乙炔还原酶活性.根据形态和其他生理特性,8903菌株为甲酸甲烷杆菌(Methanobacterium formicicum),8904菌株为巴氏甲烷八叠球菌(Methanosarcina barkeri),8905菌株为马氏甲烷八叠球菌(Ms.mazei),8901菌株和8902菌株属甲烷杆菌属(Methanobacterium spp.),其确切地位尚待进一步确定. 相似文献
3.
Weissmüller J Viswanath RN Kramer D Zimmer P Würschum R Gleiter H 《Science (New York, N.Y.)》2003,300(5617):312-315
Dimension changes on the order of 0.1% or above in response to an applied voltage have been reported for many types of materials, including ceramics, polymers, and carbon nanostructures, but not, so far, for metals. We show that reversible strain amplitudes comparable to those of commercial piezoceramics can be induced in metals by introducing a continuous network of nanometer-sized pores with a high surface area and by controlling the surface electronic charge density through an applied potential relative to an electrolyte impregnating the pores. 相似文献
4.
利用趋化方法测定了4-氯硝基苯(4-Chloronitrobenzene,4CNB)完全降解菌Pseudomonas sp.ZWL73及其接合转移子ZP8对4CNB以及可能与4CNB降解相关的15种化合物的趋化能力.结果发现,两种菌株对4CNB等12种化合物均表现出趋化性,而这些化合物大多能被用作ZWL73的生长底物,这一结果显示了ZWL73对4CNB及其降解中间产物的趋化与降解转化之间的相关性.两种菌株对试验的化合物具有相同的趋化谱表明ZWL73对4CNB的趋化也是由4CNB降解质粒所控制.本研究首次报道了微生物对氯代硝基苯的趋化现象及其遗传学的初步研究. 相似文献
5.
[目的]从土壤环境中分离出琥珀酸产量高,营养要求低的琥珀酸生产菌株。[方法]采用选择性较强的富集培养基结合溴甲酚绿快速筛选平板,从土壤中筛选、分离出产酸的菌株,利用TLC法和荧光法分离出具有不同产琥珀酸能力的菌株,并进一步利用HPLC法定性、定量。[结果]菌落为圆形凸起,表面光滑,不透明,呈淡黄色,边缘锯齿形,菌体粘稠、边缘不规则,细胞大多数单个或成双成串出现,菌体兼性厌氧,革兰氏阴性,对菌株进行生化和16S rRNA分析确认为肠杆菌属。[结论]筛选得到的肠杆菌JLT9与其他菌株相比产酸量略低,但副产物较少,培养条件简单,JLT9菌株具有好的开发研究前景。 相似文献
6.
[目的]探索对家蚕具有较好感染效果的优势蛹虫草菌株和有效的感染方法。[方法]通过蛹虫草的家蚕感染试验,研究不同感染方法对蛹虫草菌株感染能力和子实体产量的影响。[结果]悬液注射法和表面消毒浸染法的感染率较高。不同蛹虫草菌株对家蚕的感染能力存在极显著差异。菌株04718的感染效果最好,菌株7172次之,菌株04最差。利用表面消毒浸染法对家蚕进行感染,蛹虫草菌子实体得率最高。用不同蛹虫草菌株感染家蚕后,产子实体能力存在极显著差异。菌株04718感染后产子实体能力最强,菌株7172次之,菌株04较差。[结论]表面消毒浸染法和悬液注射法为利用蛹虫草菌株感染桑蚕幼虫的较好方法。 相似文献
7.
Boland JJ 《Science (New York, N.Y.)》1992,255(5041):186-188
Hydrogen can be used as an effective probe of the structure of semiconductor surfaces. Such surfaces consist of bonds with varying degrees of bond strain, and hydrogen can react with each selectively depending on the reaction conditions. This selectivity is derived from a reduced barrier to reaction associated with strained bonds. In this manner, hydrogen can be used to pick apart the surface one bond type at a time, thereby revealing the structure of even complex multilayer reconstructions. This method is used to directly show that the rest-layer of the Ge(111)-c(2 x 8) surface has a bulk structure. 相似文献
8.
9.
[目的]研究西藏龙胆根内寄生附球霉属真菌的菌株特性。[方法]以从新鲜西藏龙胆根部内分离得到的附球霉属菌株为材料,对其进行菌株鉴定与形态学观察。[结果]①菌株在PDA培养基和察氏培养基上菌落舒展,呈白色垫状,菌落到后期变为黄色,孢子黑色,基质呈黄色;而在KB培养基上菌落舒展,呈白色绒毛状,菌落到后期变黄色,孢子黑色,基质呈黄色;②菌株在25℃下培养2 d后,分生孢子在黄色菌落表面形成分散的点状黑色菌落,并有黄色色素分泌。[结论]通过相关文献查阅,发现分离得到的菌株属半知菌亚门丝孢纲瘤座孢目附球霉属的一种;菌株孢子的外形与附球霉孢子的外形相似,但在孢子纵、横隔膜隘缩的描述和柄细胞结构上与有关文献的描述有区别。 相似文献
10.
Madix RJ 《Science (New York, N.Y.)》1986,233(4769):1159-1166
One of the primary objectives of modern surface chemistry of transition metals is the synthesis of surface compounds and complexes and the understanding of their reactivity, structure, and bonding. Such considerations are paramount for advancing understanding of catalysis, adhesion, organic thin-film growth, and electrocatalysis. On selected metals, particularly copper, silver, and gold, selective scission of X-H bonds (where X is oxygen, carbon, nitrogen, or sulfur) by surface-bound atomic oxygen occurs to form moderately stable species that can be isolated for further study. Selective oxidation reactions may occur heterogeneously by means of this novel oxygen- activated route. Furthermore, this selective chemistry offers a paradigm for synthesis of a wide variety of surface organometallic complexes, whose formation can be predicted from acid-base principles. These subjects are discussed in this article with emphasis on their role in catalytic oxidation cycles. 相似文献
11.
从广西桂林的土壤中分离到一株链霉菌（编号为２３４５），它的发酵产物对线虫、菜青虫、松毛虫等畜禽寄生虫及作物害虫等的防治效果显著，它对一些格兰氏阳性菌也有明显的抑制作用，对其进行分类学研究的结果如下：按照链霉菌的分类法，该菌细胞成份属于细胞壁Ｉ型，糖Ｃ型。该菌在高氏培养基、ＩＳＰ－４等培养基上产生丰富的孢子，在斜面上则呈现一片褐色斑。该菌在培养特征、碳源利用以及形态特征等方面均近似于淡紫灰吸水链霉菌，但对淀粉利用能力很强。另外，它对枯草杆菌、藤黄八叠球菌等阳性菌的抗菌作用强，尤其是它的发酵产物可以杀死禽畜体内的线虫，故属淡紫灰吸水链霉菌桂林变种Ｓｔｒｅｐｔｏｍｙｃｅｓｌａｖｅｎｄｕｌｏｈｙｇｒｏｓｃｏｐｉｃｕｓｖａｒ．ｇｕｉｌｉｎｎ．Ｘｉａ． 相似文献
12.
以分离自葡萄叶片内生细菌菌株Zyx-3为研究对象,依据其形态特征、生理生化特性等初步确定了其分类地位,并采用平板对峙法测定了其对14种植物病原真菌的抑菌能力。结果表明,Zyx-3菌体杆状,中生芽孢,革兰氏染色阳性;菌株具有运动性和需氧性,可以使明胶液化、淀粉水解,接触酶反应阳性,具有耐盐性,可在10%NaCl培养液中生长。根据其形态特征及生理生化特性,初步确定其为芽孢杆菌（Bacillus spp.）。该菌株对玉米大斑病菌（Exserohilum turcicum）、辣椒炭疽病菌（Colletotrichum capsici）、苹果腐烂病菌（Valsa mali）、马铃薯立枯丝核病菌（Rhizoefonia solani）、半夏早疫病菌（Alternaria sonali）、苹果轮纹病菌（Physalospora piricola）、葡萄灰霉病菌（Botrytis cinerea）和葡萄白腐病菌（Coniothyrium diplodiella）、茄子菌核病菌（Sclerotinia sclerotiorum）等14种供试植物病原真菌均有不同程度的抑制作用,抑菌谱广。 相似文献
13.
Nanoparticles may contain unusual forms of structural disorder that can substantially modify materials properties and thus cannot solely be considered as small pieces of bulk material. We have developed a method to quantify intermediate-range order in 3.4-nanometer-diameter zinc sulfide nanoparticles and show that structural coherence is lost over distances beyond 2 nanometers. The zinc-sulfur Einstein vibration frequency in the nanoparticles is substantially higher than that in the bulk zinc sulfide, implying structural stiffening. This cannot be explained by the observed 1% radial compression and must be primarily due to inhomogeneous internal strain caused by competing relaxations from an irregular surface. The methods developed here are generally applicable to the characterization of nanoscale solids, many of which may exhibit complex disorder and strain. 相似文献
14.
Fibonacci number patterns and triangular patterns with intrinsic defects occur frequently on nonplanar surfaces in nature, particularly in plants. By controlling the geometry and the stress upon cooling, these patterns can be reproduced on the surface of microstructures about 10 micrometers in diameter. Spherules of the Ag core/SiOx shell structure, possessing markedly uniform size and shape, self-assembled into the Fibonacci number patterns (5 by 8 and 13 by 21) or the triangular pattern, depending on the geometry of the primary supporting surface. Under proper geometrical constraints, the patterns developed through self-assembly in order to minimize the total strain energy. This demonstrates that highly ordered microstructures can be prepared simultaneously across large areas by stress engineering. 相似文献
15.
Frequently repeated strain measurements near Palmdale, California, during the period from 1971 through 1980 indicate that, in addition to a uniform accumulation of right-lateral shear strain (engineering shear, 0.35 microradian per year) across the San Andreas fault, a 1-microstrain contraction perpendicular to the fault that accumulated gradually during the interval 1974 through 1978 was aseismically released between February and November 1979. Subsequently (November 1979 to March 1980), about half of the contraction was recovered. This sequence of strain changes can be explained in terms of south-southwestward migration of a slip event consisting of the south-southwestward movement of the upper crust on a horizontal detachment surface at a depth of 10 to 30 kilometers. The large strain change in 1979 corresponds to the passage of the slip event beneath the San Andreas fault. 相似文献
16.
应用AE和DIC原位监测含横纹裂纹木构件的裂纹演化规律试验研究 总被引：2，自引：1，他引：1
17.
[目的]优化甜瓜枯萎病拮抗链霉菌D2菌株的发酵条件,为该菌发酵方法的建立及工业化生产提供科学依据.[方法]以D2菌株有效活菌数为考察指标,玉米粉含量、豆饼粉含量、pH、摇床转速、接种量和温度为影响因素,利用响应面法对D2菌株的发酵条件进行优化.[结果]豆饼粉含量、玉米粉含量和温度对D2菌株有效活菌数有显著影响(P<0.05).D2菌株有效活菌数回归模型为:Y=8.28757+0.12344X1+0.21477X2+0.06184X3-0.05929X12-0.09817X22-0.14942X32(式中,Y为有效活菌数对数,X1、X2和X3分别为玉米粉含量、豆饼粉含量和温度的编码值),理论有效活菌数为2.99×108 CFU/mL.D2菌株最优发酵条件为:玉米粉含量39.08 g/L、豆饼粉含量39.19 g/L、培养温度37.4℃,在此条件下D2菌株有效活菌数为3.01×108 CFU/mL,与理论值接近,但极显著高于未经优化采用培养基Ⅱ得到的有效活菌数(1.0×106 CFU/mL)(P<0.01).[结论]采用响应面法优化得到的D2菌株发酵条件可有效提高该菌株有效活菌数,且回归模型推算出的理论活菌数与优化条件发酵的有效活菌数接近,可用于指导D2菌株的实际规模化生产. 相似文献
18.
6株放线菌定殖能力测定及对苹果灰霉病控制效果 总被引：1，自引：0，他引：1
通过菌药结合试验,测定了6株生防菌株在套袋苹果和叶片表面定殖能力以及它们对苹果表面真菌的控制能力,并分别测定了其发酵液、菌悬液及发酵滤液对采后苹果灰霉菌(Botrytis cinerea)的抑制效果.结果表明:菌株15-3在套袋苹果以及苹果叶片上具有很强的定殖能力,对苹果表面的真菌也有较好的抑制效果;菌株SC1能够有效地抑制套袋苹果表面以及苹果叶片表面真菌的生长繁殖;6株生防放线菌发酵液对苹果灰葡萄孢都具有明显的抑制作用,菌株SC1、A3、SE2和15-3的发酵液对苹果灰葡萄孢的控制作用均超过80%,菌株15-3的菌悬液也具有一定的抑制效果. 相似文献
19.
Nano-grained (NG) metals are believed to be strong but intrinsically brittle: Free-standing NG metals usually exhibit a tensile uniform elongation of a few percent. When a NG copper film is confined by a coarse-grained (CG) copper substrate with a gradient grain-size transition, tensile plasticity can be achieved in the NG film where strain localization is suppressed. The gradient NG film exhibits a 10 times higher yield strength and a tensile plasticity comparable to that of the CG substrate and can sustain a tensile true strain exceeding 100% without cracking. A mechanically driven grain boundary migration process with a substantial concomitant grain growth dominates plastic deformation of the gradient NG structure. The extraordinary intrinsic plasticity of gradient NG structures offers their potential for use as advanced coatings of bulk materials. 相似文献
20.
Bevis M 《Science (New York, N.Y.)》1988,240(4857):1317-1319
The rate of accumulation of seismic moment in Wadati-Benioff zones is used to estimate strain rates in subducting slabs that are sinking through the asthenosphere. Between depths of 75 and 175 kilometers a typical down-dip strain rate is about 10(-15) per second, which implies that slabs in this depth range typically accumulate strain of order 10(-1). This result is in accord with geometrical arguments that subducted slabs must experience large membrane strains to deform to their observed shapes. Mantle seismicity (repeated catastrophic shear failure) is apparently a primary mechanism by which large membrane strains accumulate in the cold cores of subducting slabs. Slabs are penetratively deformed, and they have low flexural rigidity compared to oceanic plates at the earth's surface. 相似文献