拮抗菌HT-6对致病疫霉的竞争及诱导性抑制

为深入了解细菌HT-6对致病疫霉(Phytophthora infestans)菌丝生长的抑制机理,采用琼脂柱对接法观察细菌HT-6对致病疫霉空间位点的竞争,铬天青(CAS)培养基观察嗜铁素的产生,硫酸-蒽铜比色法和水杨酸浓硫酸比色法分别比较葡萄糖和硝态氮的利用率,同时以致病疫霉及其细胞壁制剂(CWP)为诱导物,采用平板透明圈法观察HT-6产生的纤维素酶和β-1,3-葡聚糖酶,DNS法测定酶活并评价含有2种酶的无菌体发酵液对致病疫霉的抑制活性.结果显示,单独接种在PDA琼脂柱上的致病疫霉能沿琼脂柱生长并迅速扩展至黑麦固体培养基(Rye)表面生长,与致病疫霉菌饼对接的HT-6也能沿着琼脂柱生长并扩展至Rye培养基表面迅速蔓延,而与HT-6对接的致病疫霉菌丝体仅在PDA琼脂柱上生长,没有扩展至Rye表面,被HT-6的生长所阻止;HT-6能产生嗜铁素,致病疫霉不产生嗜铁素;HT-6对葡萄糖和硝态氮的利用率(75.66%和69.05%)均显著高于致病疫霉(55.97%和56.87%);HT-6菌株单独培养时不产生纤维素酶和β-1,3-葡聚糖酶,但致病疫霉菌体和CWP均能诱导HT-6产生这2种酶,其中菌体诱导后的2种酶活,分别为6.638、2.913 U,均显著高于CWP的诱导处理(1.326、1.289 U,P<0.05);CWP诱导后含有2种酶的HT-6无菌体发酵液对致病疫霉菌丝生长具有明显抑制作用(抑菌率为33.25%),但显著低于单独培养的HT-6菌液原液的抑菌活性(抑菌率为81.33%).这表明HT-6能够通过空间和营养竞争以及致病疫霉诱导产生的细胞壁降解酶抑制致病疫霉,其中以空间和营养竞争为主.     

致病疫霉诱导放线菌Sy11菌株的抑菌作用

在筛选致病疫霉拮抗菌过程中,发现放线菌Sy11菌株对致病疫霉的抑制作用是由于致病疫霉对Sy11的诱导作用.为了进一步明确致病疫霉对Sy11的诱导方式和条件,采用平板对峙共培养法探讨了致病疫霉诱导Sy11的适宜培养基、培养温度、培养时间以及诱导后Sy11菌株抑菌作用的持续时间等.结果显示,只有活体致病疫霉才能诱导Sy11的抑菌作用,死亡的致病疫霉菌体没有诱导作用;用黑麦培养基20℃黑暗对峙培养7d,从Sy11菌落向外12mm处的无菌体琼脂块的抑菌作用最强,抑菌率达到79.38%,与Sy11菌株完整菌落的抑菌率86.47%相近;而且发现致病疫霉诱导1次后,Sy11的抑菌能力即可连续传递13代,且抑菌率保持在65%以上.这些结果表明,Sy11是在受到活体致病疫霉诱导之后才对致病疫霉有抑制作用,且抑菌作用具有遗传性.     

对放线菌Sy11有诱导作用的致病疫霉信号分子研究

致病疫霉(Phytophthora infestans)能产生一种信号分子,诱导放线菌Sy11菌株产生抑菌物质从而抑制致病疫霉.为明确在哪种培养方式下致病疫霉更易产生这种信号分子以及信号分子的物质类别,本文采用生长速率法对致病疫霉单独培养(单独固体培养和单独液体培养)以及与Sy11共培养(对峙培养和混合培养)产生的信号分子诱导Sy11抑菌作用的活性进行了比较,并以不同有机溶剂对信号分子的物质类别进行了初步分析.结果显示,致病疫霉无论单独培养还是与Sy11共培养,均可产生诱导Sy11抑菌作用的信号分子,其中以在固体黑麦培养基上与Sy11对峙培养产生的信号分子的诱导活性最强,菌落直径为24.79 mm,但与其他3种培养方式所产生的信号分子的诱导活性并无显著性差异;对致病疫霉单独液体培养后无菌体发酵液的分析表明,其中脂类粗提物的诱导活性(菌落直径32.8 mm)远高于糖类(菌落直径61.5 mm)和蛋白质类(菌落直径60 mm)粗提物,进一步对其中脂类物质的萃取显示,乙酸乙酯的萃取效果明显优于乙醇和石油醚.乙酸乙酯萃取物诱导Sy11后对致病疫霉菌丝生长有显著的抑制作用(菌落直径为35 mm)与乙醇萃取液的处理达到显著性差异.以上结果表明,致病疫霉生长过程中无论单独培养还是与Sy11共培养均可产生能诱导Sy11抑菌作用的信号分子,该信号分子以脂类物质为主,可用乙酸乙酯萃取得到.     

致病疫霉菌株交配型的检测及其检测方法的比较

致病疫霉(Phytophthora infestans)是马铃薯晚疫病的病原体,可导致马铃薯大面积减产。致病疫霉的有性生殖可以产生卵孢子,由于其抗逆性较强,利于致病疫霉渡过不利的生存环境,给马铃薯晚疫病的有效防治带来巨大的困难。致病疫霉的有性生殖属于异宗配合,即A1、A2交配型同时培养时才会产生卵孢子。因此,快速而有效地检测致病疫霉菌株的交配型将为致病疫霉有性生殖分子机理的研究及致病疫霉的防治奠定基础。通过直接配对法、纸盘法和分子标记法三种方法,对5株来源不同的致病疫霉菌株进行了交配型检测。三种方法的检测结果均表明,菌株HQK8-3、2PO-D、USA1的交配型与ATCC标准菌株64093的交配型一致,为A1交配型,而菌株2PO82001、P7723的交配型与ATCC标准菌株32835的交配型一致,为A2交配型。说明三种方法均可有效鉴定致病疫霉交配型,但三种方法各有优缺点,应根据实验条件,采取合适的方法进行菌株交配型测定。     

不同致病力棉花黄萎病菌乙烯含量及相关基因表达量的测定

为了分析大丽轮枝菌(Verticillium dahliae Kleb.)乙烯合成与致病力的关系,本研究以棉花黄萎病菌落叶型强致病力菌株V592和非落叶型弱致病力菌株V774为研究对象,分别将2个菌株于非诱导查氏培养液中和添加棉花根提取物的诱导查氏培养液中进行培养,对其乙烯含量进行测定,并通过qRT-PCR分析大丽轮枝菌中6个与乙烯合成相关基因的表达量。结果表明:强、弱致病力菌株均能产生乙烯,强致病力菌株产生的乙烯含量明显高于弱致病力菌株,且强致病力菌株合成乙烯的能力受寄主根诱导后明显加强。非诱导条件下4个基因在强、弱致病力菌株中的表达量存在差异;在诱导条件下6个基因在强、弱致病力菌株中的表达量存在明显差异(P0.05)。这些基因的差异表达可能是造成强、弱致病力菌株乙烯含量不同的主要因素。     

臭蒿水乳剂抗烟草黑胫病的作用

采用菌丝生长速率法,测定臭蒿水乳剂对烟草疫霉菌丝生长的毒力及其药效稳定性;采用菌丝块诱导孢子囊产生法测定臭蒿水乳剂对烟草疫霉孢子囊抑制的毒力;最后对盆栽防效结果进行探讨.结果表明,低浓度臭蒿水乳剂对烟草疫霉菌丝生长和孢子囊的产生均有明显抑制作用,对烟草疫霉菌丝生长抑制的EC50和EC90值分别为5.93g·L-1、52.56g·L-1,其对烟草疫霉菌丝生长的抑制作用具有良好的pH值稳定性、光稳定性、热稳定性以及贮藏稳定性;对烟草疫霉孢子囊产生抑制的EC50、EC90值分别为6.56g·L-1,65.22g·L-1.盆栽防效及对烟草幼苗生长影响实验表明,22d其对烟草黑胫病的防效为56.2%,且对烟草幼苗生长几乎没有影响.     

濒危植物延龄草愈伤组织诱导研究

通过延龄草愈伤组织诱导研究发现,延龄草根茎所产生的愈伤组织在1/2 MS BA(苄基氨基嘌呤)1.2 mg.L-1 IAA(吲哚乙酸)0.6 mg.L-1培养基中较好,诱导频率为83.33%;在1/2 MS BA 1.2 mg.L-1 IAA 1.2 mg.L-1培养基中次之,诱导频率为66.67%;在1/2 MS BA 1.2 mg.L-1 IAA 0.2 mg.L-1培养基中也能产生,但质地较差,诱导频率为22.22%;在1/2 MS BA 1.2 mg.L-1 NAA(萘乙酸)0.2mg.L-1培养基中也能产生少量.可见,以1/2 MS作为基础培养基,加入1.2 mg.L-1BA和0.6 mg.L-1IAA,以根茎为外植体进行延龄草组织培养,能产生大量的愈伤组织.研究表明,利用组织培养繁殖延龄草是一种有效、可行的途径.     

稻飞虱虫霉研究初报

我们从褐稻虱上分离到一种虫霉,经多次测试表明,此菌对褐稻虱、白背稻虱和灰稻虱均有寄生致病能力.其寄生致死率一般可达60-80%.但对稻叶蝉无效.飞虱虫霉的生长和产孢温度范围是15-35℃,以25-30℃最适.pH3.5-11.5均能生长,但以pH5最佳.孢子囊对光较敏感,在直射日光或紫外光(30w)下经1-2小时,大多数丧失生活力,但不受散射光的影响.孢子囊的形成、弹射、萌发及侵入均需高湿.对培养基要求不严格,马铃薯葡萄糖洋菜培养基、马铃薯片、甘薯片等均能良好生长繁殖.休眠孢子在室温下可存活一年以上.稻飞虱感染虫霉后,快则1-2天,慢则4-5天即罹病致死.     

枯草芽孢杆菌WL2脂肽粗提物对致病疫霉的抑制作用及其分离鉴定

为明确枯草芽孢杆菌(Bacillus subtilis)WL2产生的脂肽对致病疫霉菌丝体生长的影响及其预防马铃薯晚疫病的潜力,以滤纸片法检测脂肽粗提物对菌丝生长的抑制效果,显微镜观察脂肽粗提物对致病疫霉孢子萌发的影响,离体组织培养法明确脂肽粗提物对晚疫病的预防效果,高效液相色谱法(HPLC)纯化脂肽、电子喷雾质谱(ESI-MS)鉴定脂肽种类.结果表明,当脂肽粗提物质量浓度为25μg/mL时,抑菌圈直径为5.9mm,抑制后的菌丝恢复生长速度仅有5.2mm/d,与对照组(11.2mm/d)存在显著差异(P0.05);当脂肽质量浓度为3μg/mL时,孢子囊萌发比率只有9.7%,用质量浓度为4μg/mL的脂肽抑制后,释放游动孢子比率只有7.6%,与对照组均存在显著差异(P0.05);脂肽粗提物(20μg/mL)对晚疫病的预防效果最好,病情指数最低(20.6),与对照组病情指数(73.1)有显著差异(P0.05);经HPLC分离和ESI-MS鉴定,明确了WL2菌株可产iturinA和surfactin两类脂肽物质.以上结果说明WL2菌株产生的脂肽在预防马铃薯晚疫病方面具有较大的潜力.     

拮抗菌HT-6引起致病疫霉菌体的生理变化

为了解核桃内生细菌HT-6对致病疫霉的抑制作用机理,采用对峙培养和传统培养相结合的方法检测了受拮抗菌HT-6抑制不同阶段后致病疫霉菌丝体内部分活性物质、抗性相关酶活、电导率以及溶氧量的变化.结果显示,随对峙培养时间延长,受抑制组与对照组中致病疫霉菌丝体内可溶性糖和淀粉含量虽然均呈增加趋势,蛋白质含量均呈下降趋势,但受抑制组可溶性糖、淀粉及蛋白质含量均远低于对照组,且均在对峙培养第15天时差异最大(P<0.01);受抑制组和对照组菌丝体内苯丙氨酸解氨酶、多酚氧化酶和过氧化物酶3种酶活的变化趋势与上述3种物质的变化趋势相似,但均在培养的第12天达到最高,且受抑制组菌体内3种酶活均远高于对照组,与对照达到极显著差异(P<0.01).此外,受拮抗菌HT-6抑制后致病疫霉菌丝体内的电导率(162.77 μS/cm)显著高于对照组(60.03 μS/cm),而溶氧量(47.13%)显著低于对照组(56.1%).这些结果表明:HT-6菌株可通过抑制或大量消耗致病疫霉菌丝体内部分活性物质,同时增加细胞膜透性、降低呼吸作用实现对致病疫霉菌丝体生长的抑制作用.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has