Regional epidemic laws of poplar Ice Nucleation Active bacterial canker

Through the methods of correlation analysis and main factor analysis, the relationship between the poplar INA bacte-rial canker and circumstances was analyzed and 9 main factors for affecting the disease were selected. Based on the compre-hensive analysis of main factors and induced factors, the standard for risk grades of this disease was promoted and northeast region of China was divided into 4 districts with different risk grades: seriously occurring district, commonly occurring district, occasionally occurring district, and un-occurring district. Nonlinear regression analysis for six model curves showed that the Richard growth model was suitable for describing the temporal dynamics of poplar INA bacterial canker. By stepwise variable selection method, the multi-variable linear regression forecasting equation was set up to predict the next year抯 disease index, and the GM (1,1) model was also set up by grey method to submit middle or long period forecast.

Pathogenetic and physiological mechanisms of poplar ice nucleation active bacterial canker

Using the methods introduced by Bier, X.H., Buchinock, Wang Jing-wen, Shi Rihe et al., different varieties of poplar (poplar-Mei譗ing, Poplar-A100, Poplar-Xiaohe14 et al.) were inoculated with poplar ice nucleation active (INA) bacteria respec-tively in 1997-1999. The water content, relative turgidity, lignin content, phenylalanine ammonialyase (PAL) activity, electrolyte effusion rate, and inorganic element content of poplar bark were measured before and after inoculating. The results showed that after the poplar trees were inoculated with INA bacteria, the moisture content of bark decreased but relative turgidity increased, electrolyte effusion rate increased and had a peak at temperatures of 4 and 5 C, lignin content increased and positively cor-related with poplars disease-resistance, and the plenylalanine ammonialyase activity increased and also showed a significant positive correlation with poplars disease-resistance. For the contents of inorganic element, Cu and Fe decreased but K and Zn increased obviously, while Mn, Ca and Mg changed little.

Experimental Study on the Dependency of Ice Nucleation Active Surface Site Density on ATD Aerosol Size

In light of the percentage of Earth’s cloud coverage, heterogeneous ice nucleation in clouds is the most important global-scale pathway. More recent parameterizations of ice nucleation processes in the atmosphere are based on the concept of ice nucleation active surface site density (ns). It is usually assumed that ns is independent of time and aerosol size distribution, i.e. that the surface properties of aerosols of the same species do not vary with size. However, the independence of ns on aerosol size for every species has been questioned. This study presents the results of ice nucleation processes of ATD laboratory-generated aerosol (particle diameters of 0 - 3 μm). Ice nucleation in the condensation mode was performed in a Dynamic Filter Processing Cham- ber at temperatures of -18°C and -22°C, with a saturation ratio with respect to water of 1.02. Results show that ns increased by lowering the nucleation temperature, and was also dependent on the particle size. The ns of particles collected on the filters, after a 0.5 μm D50 cut-off cyclone, resulted statistically higher with respect to the values obtained from the particles collected on total filters. The results obtained suggest the need for further investigation of ns dependence of same composition aerosol particles with a view to support weather and climate predictions.

冰核细菌Erwinia ananas 110冰核基因iceA的原核表达及冰核活性分析

为获得具有高冰核活性的基因工程菌,从冰核细菌Erwinia ananas 110扩增冰核基因iceA,将其克隆到pMD19–T载体上,转化大肠杆菌DH5α,单、双酶切鉴定并测序;阳性克隆目的片段亚克隆到表达载体pET–23a(+)上,转化大肠杆菌DH5α,单、双酶切鉴定重组质粒;阳性重组质粒转化大肠杆菌BL21(DE3)pLysS,并经IPTG诱导表达。SDS–PAGE电泳检测表明,冰核基因iceA能够并以包涵体形式表达,相对分子质量约为180 000。冰核活性测定结果表明,重组菌BL21(DE3)pLysS/pET–ice的冰核活性与野生冰核细菌Erwinia ananas 110在–5、–4、–3、–2℃下无明显差别。

Effects of Low Temperature Stress and INA Bacteriaon Chlorophyll a Fluorescence Induction Kineticsin Young Fruit of Two Apricot Cultivars

Effects of low temperature and INA bacteria on the change of chlorophyll a fluorescence in young fruit from two apricot cultivars were investigated. Low temperature decreased the potential activity (Fv/ Fo), conversion efficiency of primary light energy (Fv/Fm)of PS II and photochemical quenching (qP) in young fruit of two apricot cultivars. Low temperature enhanced non-photochemical quenching qN, decreasing the quantum yield of photosynthetic electron transfer. The presence of ice nucleating active (INA) bacteria intensified the effects of low temperature, raised the injury temperature threshold from - 4℃ to - 2 - - 3℃. INA bacteria can be a factor to induce frost susceptibility of apricot fruit. The amount of damaged PS I activity center was related to apricot fruit size and cultivar.

Human activity over natural inputs determines the bacterial community in an ice core from the Muztag ata glacier

Ice core provides a valuable vertical timeline of past climates and anthropogenic activities.Environmental proxies have been widely used in these studies,but there are few biological indicators available.To address this gap,we investigated the bacterial community from a 74 m ice core of Muztag ata glacier on the Tibetan Plateau to link biological indicators with past climate and anthropogenic activities.By analyzing the portion of the ice core with environmental proxies available(corresponding to 1907 to 1991),we observed an increase in bacterial richness throughout the ice core,which was associated with higher NH_(4)^(+),an indicator of agricultural development.The bacterial community was jointly determined by human activity,natural input,and air temperature,with a strong human influence after the 1950s.Furthermore,the relative abundance of animal gut-associated bacteria,including Aerococcaceae,Nocardiaceae,Muribaculaceae,and Lachnospiraceae,was associated with livestock number changes in the Central Asian region.Together with other bacterial lineages,they jointly explained 59.8%of the livestock number changes.This study provides quantitative evidence of the associations between bacterial indicators and past climate and human activities,highlighting the potential of using bacterial proxies for ice core studies.

树木防冻防病膜剂室内抑菌效果研究

【目的】探究树木防冻防病膜剂的抑菌效果,为生产提供一种良好的防冻保护剂。【方法】利用课题组研制的树木防冻防病膜剂对2种冰核细菌(丁香假单胞菌和菠萝泛生氏菌)和3种真菌(小穴壳菌属、金黄壳囊孢菌、污黑腐皮壳菌)进行抑菌效果研究,并与市面常用药剂进行比较。采用滤纸片扩散法对比3个浓度(0.3‰、0.6‰和1‰)下农用链霉素和防冻防病膜剂对两种冰核细菌抑制效果。采用生长速率法对比4个浓度(100 mg·L^(-1)、300 mg·L^(-1)、600 mg·L^(-1)和1000 mg·L^(-1))下多菌灵、甲基硫菌灵、百菌清和防冻防病膜剂4种药剂对3种引起杨树溃疡病和烂皮病真菌的抑制效果。【结果】(1)与农用链霉素相比,防冻防病膜剂对2种冰核细菌的抑制效果较好,且抑菌效果随着药剂浓度的增大而增大。在设置的最高试验浓度下,防冻防病膜剂对丁香假单胞菌和菠萝泛生氏菌的抑菌直径分别为10.9 mm和19.1 mm。(2)多菌灵和甲基硫菌灵对3种真菌抑制效果较好,多菌灵在100 mg·L^(-1)浓度下对3种真菌抑制率能达到100%,甲基硫菌灵在100 mg·L^(-1)浓度下对2种真菌(金黄壳囊孢菌、污黑腐皮壳菌)抑制率能达到100%,在600 mg·L^(-1)浓度下对小穴壳菌属抑制率能达到100%。(3)防冻防病膜剂与百菌清对3种真菌的抑制效果相当,防冻防病膜剂的抑制效果随着药剂浓度增大而增强,当浓度达到1000 mg·L^(-1)时,抑菌率为100%。【结论】树木防冻防病膜剂对2种冰核细菌和3种真菌均有较好抑制效果。

冰核细菌对仁用杏胚珠超微结构的影响

应用透射电镜对两个仁用杏品种‘白玉扁’和‘一窝蜂’接种冰核细菌并低温处理后的胚珠超微结构进行了观察 ,发现冰核细菌对胚珠的超微结构有一定影响 :(1)使珠心细胞发生严重的质壁分离 ,细胞质中存在大量泡状结构 ,线粒体的内部结构完全被破坏 ,呈透明状 ,而且有些珠心细胞中形成同心圆状的多膜内含物 ;(2 )使胚囊中卵细胞的细胞核外膜膨胀 ,甚至核膜局部解体 ,细胞质中细胞器减少。这些变化致使胚珠发育不正常 ,影响受精而导致减产或绝收。

冰核活性细菌发酵培养基的优化筛选

研究了不同营养构成及添加不同营养物质对冰核细菌生长和冰核活性的影响 ,采用正交试验优化了培养基组成。优化后的培养基最佳配方为 :在MPDA培养基中添加 0 4%半乳糖、1 5 %酵母粉、0 0 1%粗磷脂。在优化后的培养基中培养供试菌 ,菌体收获量 (干重 )比在MPDA培养基中培养增加 2 4g/L ,冰核活性增加 2 4 3 %。

冰核细菌表达冰核蛋白特性的研究

选用１００２５Ａ和ＱＦ－９５－Ｆ１９两株分离自杨树的冰核活性细菌，探讨了两株菌不同生长阶段与它们冰核活性表达的特性。实验结果显示，冰核活性细菌在ＭＰＤＡ培养液中表达冰核蛋白的特性及活性与细菌浓度、菌龄以及培养的环境条件相关，两株菌在表达冰核活性时对培养基的营养组分没有表现出特殊的要求。同时还进一步阐明了不同生长温度冰核活性细菌对冰核蛋白表达的影响。

冰核活性细菌及其在食品冻结浓缩中的应用

介绍冰核细菌的成冰机制、预处理工艺及在食品中的冷冻效率、冰晶形成结构与应用方面的最新进展 。

黄单胞冰核活性细菌发酵制备的初步研究

应用正交设计与均匀设计对黄单胞冰核活性细菌的发酵制备条件进行了初步研究。结果表明 ,琥珀酸抑制了黄单胞菌生长与冰核活性的表达 ,甘油、蔗糖、乳糖、谷氨酸钠不同程度地促进了冰核活性和单胞菌的生长。较优培养基配方为酵母粉 1%、大豆蛋白胨 1%、MgSO4 ·7H2 O 0 0 5%、甘油 1%、蔗糖 2 %、乳糖 1%、谷氨酸钠 0 3% ,pH 7 0 ;较优发酵组合为细菌种龄 72h ,发酵时间 4

生物冰核研究与应用的现状和前景

引起水由液态变为固态的物质称为冰核或成核剂 ,冰核是多种多样的 ,可为无机物、有机物等非生物 ,也可是生物 ,目前已发现 4属 2 3种或变种的细菌、4属 11种或变种的真菌和一种病毒具成冰活性。细菌冰核是一类蛋白质 ,称冰蛋白 ,由细菌冰核基因编码 ,已有 11种冰核细菌的冰核基因被克隆并在大肠杆菌中得到表达 ,冰核基因编码的冰蛋白成冰活性比较弱 ,冰蛋白通过脂、碳水化合物等共价修饰装配成成冰活性较强的冰核。真菌冰核也可能是蛋白质 ,其与细菌冰核在特性上有许多差异。影响细菌冰核成冰活性的因素较多 ,主要有菌液浓度、培养基的组成、培养温度和 p H值等。生物冰核是引起和加重植物霜害和冻害的重要因子 ,并与弱寄生真菌引起的植物病害有重要的联系 ,通过防除冰核生物减少霜害和冻害的发生、控制病害的发展 ,在某些方面已得到显著效果。生物冰核是一类重要的资源 ,已成功地应用于人工降雪、制冷和高敏检测 。

冰核细菌生物学特性及其诱发植物霜冻机理与防霜应用

就国内外有关冰核细菌生物学特性及其诱发植物霜冻机理与防霜应用的研究进展作以概述。阐述了冰核细菌种类、分布、影响冰核活性的成冰因素 ,冰核活性等级划分、冰核细菌保存方法以及冰核细菌诱发植物霜冻机理 ;简介了冰核细菌分子生物学研究进展 ;药剂和生防菌能够防除植物上冰核细菌减轻或控制霜冻危害 ,并已取得成效 ,是防御植物霜冻的一条新途径。

果树霜冻害研究进展

介绍了霜冻害对果树的危害、霜冻害的机理和防霜措施的研究概况 ;还扼要介绍了冰核活性细菌与果树霜冻害的关系及其近年来国内外的研究进展 ;

云南植物上冰核活性细菌鉴定

从云南植物上分离到９２株冰核活性细菌，并进行了鉴定。其中菠萝欧文氏菌６１株，占６６．３％；草生欧文氏菌２株，占２．２％；丁香假单胞菌２１株，占２２．８％；黄瓜角斑病菌２株，占２．２％；菜豆荚斑假单胞菌６株，占６．５％。云南省冰核活性细菌的优势种类是菠萝欧文氏菌，其次是丁香假单胞菌类。

我国冰核活性细菌的优势种类调查与研究

１９８６～１９９４年，从国内１７个省、市、自治区的６８种植物上分离到了２５０株冰核活性细菌，经鉴定分别属于３个属的１７个种或致病变种。其中出现最多的是菠萝欧文氏菌（Ｅｒｗｉｎｉａａｎａｎａｓ），共１３３株，占总数的５３．２％，其次是丁香假单胞菌群（Ｐ．ｓｙｒｉｎｇａｅｐｖｓ．），共７０株，占２８％，其它种类的冰核活性细菌共４７株，仅占１８．８％。因此，我国冰核活性细菌的优势菌种是Ｅ．ａｎａｎａｓ，其次是Ｐ．ｓｙｒｉｇａｅｐｖｓ．在低纬度的南方地区中Ｅ．ａｎａｎａｓ的优势尤其明显，而在纬度较高的北京地区中则以假单胞菌类稍占优势。黄单胞菌属的ＩＮＡ细菌出现频率少，一般出现在冬季较为寒冷的地区中的禾本科植物上。

冰核细菌在我国北方玉米上的消长动态规律

研究证明,菠萝欧文氏菌(Erwinia ananas)为我国北方玉米上优势冰核细菌种类,占总体INA细菌95 %以上。采用定量定性和定期取样分离方法,首次研究INA细菌在玉米上的消长动态规律。结果表明:玉米不同生长发育阶段是影响INA细菌在玉米上数量分布和消长动态变化的重要因素,以抽雄至成熟期间分布INA细菌数量最多,高达10 7～10 8CFU/ g,比拔节至抽雄期高出2～3个数量级,比苗期至拔节期高出4～5个数量级;同时还指出,玉米不同播期,对INA细菌数量分布影响显著,差异很大,其中INA细菌分布数量消长变化,以正常播种(1.9×10 7CFU / g) >中期播种(7.9×10 5CFU/ g) >晚期播种(5 .0×10 4 CFU/ g) ;研究指出,处于抽雄至成熟期间的玉米上分布的INA细菌数量最多,因此期间(8月上旬至9月下旬) ,气温逐渐降低,昼夜温差大,田间结露多,加上玉米处于成熟阶段,抗INA细菌能力弱,这些因素有利于低温(5～2 0℃范围内生长)型INA细菌生长繁殖。

冰核活性细菌灭活方法的初步研究

探讨了几种灭活方法对冰核活性细菌死亡率和冰核活性的影响。结果表明:超声波破碎法使冰核细菌10025A的死亡率达到98%以上,但冰核活性有所下降。辐射处理可使冰核细菌达到100%的死亡率,不同菌种对辐射的敏感程度不同,冰核活性的变化也有所不同。其它方法处理的冰核细菌死亡率较低。

抗茶树冰核细菌内生菌的筛选及鉴定

从茶树内生菌中进行了冰核细菌拮抗菌的筛选,得到菌株Y1,通过对菌株Y1进行形态学观察、生理生化指标测定及16 S r DNA序列测定和序列同源性分析,将菌株Y1鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。本研究获得了茶树内生拮抗菌株,明确了菌株Y1的种属,有利于冰核细菌生物防治的开展。