Pathogenicity and Virulence of the Two Dutch VCGs of Verticillium dahliae to Woody Ornamentals

Two experiments were performed in two consecutive years to test whether isolates of different vegetative compatibility groups (VCGs) differ in their ability to cause disease in woody ornamentals, to study the host specificity of the isolates and to get an insight into disease development in woody hosts. A range of woody ornamental plant species, including Acer campestre, Acer platanoides, Acer pseudoplatanus, Catalpa bignonioides, Cotinus coggygria, Robinia pseudoacacia, Rosa canina, Syringa vulgaris and Tilia cordata, were root-dip inoculated with six isolates of Verticillium dahliae, belonging to the two VCGs that occur in the Netherlands (VCG NL-1 and VCG NL-2). Isolates belonging to each VCG caused severe symptoms of verticillium wilt in most plant species tested. Disease progress differed between plant species, but was generally the same for the two VCGs. No overall differences in virulence were observed between the two VCGs for external wilt symptoms, number of dead plants, or shoot length. No significant VCG × plant species interactions were present for these characteristics. However, isolates of VCG NL-1 caused more vascular discolouration than did isolates of VCG NL-2. Isolates within VCGs often differed considerably in their virulence to certain hosts, as shown by highly significant isolate × plant species interactions. Isolates were more virulent on their original host. These findings imply that VCG identification does not contribute to disease prediction for a range of woody hosts.     

硬脂酸-胱氨酸-大豆分离蛋白复合膜的机械特性和吸湿性研究

以硬脂酸作为增塑剂,胱氨酸作为交联剂制备具有一定力学性能和良好抗湿性能的大豆分离蛋白复合膜。将膜放在25℃,相对湿度为50%的干燥器中平衡两天,用质构仪测定膜的抗拉强度(TS),延伸率(E(%))。在水分活度a_w为0.10～0.90的范围内研究了复合膜在25℃的吸湿特性。吸湿速率和吸湿等温线数据分别拟合到Peleg's 方程和GAB(Guggenheim-Anderson-de Boer)模型。结果表明：大豆蛋白复合膜的TS、延伸率E(%)以及吸湿速率随着硬脂酸和胱氨酸的添加比率显著地变化。硬脂酸和胱氨酸的最佳添加比率为40∶60(w/w)(每升蛋白质溶液中加入10 g混合添加剂),此时,大豆蛋白膜的强度比原来提高2倍,并且有最佳的吸湿速率。吸湿数据和GAB 模型有很高的拟合度,拟合系数最高达0.99。     

可食性绿豆淀粉基复合膜的制备及其在青脆李保鲜中的应用

以绿豆淀粉和大豆分离蛋白为制膜原料,通过考察二者复合比例对可食性绿豆淀粉基复合膜性能的影响,研究可食性绿豆淀粉基复合膜的最佳复合比例,同时利用傅里叶红外光谱仪和扫描电镜对该复合膜进行结构表征,并考察其对青脆李贮藏品质的影响。结果表明：在绿豆淀粉与大豆分离蛋白复合比例为2∶1时,绿豆淀粉基复合膜表现出良好的膜性能,此时溶解度、水蒸气透过系数、抗拉强度和断裂伸长率分别为18%、1.2×10^-5g·mm·cm^-2·h^-1·Pa^-1、35 MPa和21.4%。与绿豆淀粉膜相比,该复合膜组分间的相容性较好,且表面更平滑、均匀。在常温贮藏期间,用该复合膜涂膜的青脆李硬度、可溶性固形物和可滴定酸含量等品质指标均优于未涂膜组,可作为青脆李的保鲜膜材料。     

猪Ghrelin基因的克隆及原核表达

从猪下丘脑、胃等组织中提取总RNA，根据已发表的猪的Ghrelin mRNA序列设计合成引物，通过RT-PCR进行cDNA扩增，获得了282bp的片段。将该片段克隆于pMD-18T载体后进行序列分析，确认PCR产物为Ghrelin cDNA。从阳性克隆中提取质粒，经NheⅠ和XhoⅠ双酶切，回收282bp的目的片段，定向克隆到pET-28a表达载体中，提取质粒并再次转化到BL21（DE3）中，成功地筛选出阳性克隆。经IPTG诱导阳性菌，通过SDS-PAGE检测出猪Ghrelin基因的表达．     

传染性法氏囊病病毒变异E株对法氏囊生长发育的影响

本试验全面而系统地观察了传染性法氏囊病病毒变异Ｅ株,通过泄殖腔、鼻腔和尿囊腔接种雏鸡和鸡胚后不同时间法氏囊的组织形态学变化。结果表明,病毒感染后１２～４８小时,雏鸡法囊粘膜上皮细胞肿胀、坏死脱落,淋巴滤泡髓质部及皮质部淋巴细胞不同程度变性、坏死、排空,形成腺管样结构或囊状空泡,接毒后７２～１４４小时,法氏囊淋巴滤泡淋巴细胞坏死排空,淋巴滤泡萎缩,网状结缔组织大量增生,而胚胎发育时期,法氏囊粘膜上皮肿胀变性,法氏囊淋巴滤泡形成延迟或不完整,淋巴滤泡内淋巴细胞缺乏或空虚。探讨了传染性法氏囊病病毒对胚胎发育时期的雏鸡发育时期法氏囊生长发育的影响。     

纳米氧化锌/葡萄皮红改性大豆分离蛋白膜的制备与性能研究

为改善大豆分离蛋白膜的性能,将纳米氧化锌（ZnO Nanoparticles,ZnO NPs）和葡萄皮红（Grape-Skin Red,GSR）加入大豆分离蛋白（Soy Protein Isolate,SPI）中制备SPI/ZnO NPs/GSR复合膜,对复合膜的性能进行表征。结果表明当葡萄皮红、ZnO NPs和大豆分离蛋白以1∶2∶25的质量比制备复合膜时,相对于SPI/ZnO NPs膜,葡萄皮红可提高ZnO NPs和大豆分离蛋白的相容性,改善ZnO NPs在SPI膜中的分散性,并与ZnO NPs发挥协同作用提高SPI膜的机械性能、耐水性能和热稳定性（P<0.05）。SPI/ZnO NPs/GSR复合膜相比较于SPI膜,拉伸强度从1.37 MPa升至3.28 MPa,熔点从194 ℃升至231 ℃,含水率从34.41%降至25.37%,水蒸气透过系数从5.57×?10-12 (g·cm)/(cm2·s·Pa)降至4.74 × 10-12 (g·cm)/(cm2·s·Pa)。此外,复合膜对金黄色葡萄球菌和大肠杆菌表现出优异的抗菌性能,抑菌圈直径随着活性成分的添加呈上升趋势（大肠杆菌：SPI膜无,SPI/ZnO NPs膜2.29 cm,SPI/ZnO NPs/GSR膜2.36 cm;金黄色葡萄球菌：SPI膜无,SPI/ZnO NPs膜2.32 cm,SPI/ZnO NPs/GSR膜2.42 cm）,在活性包装应用中具有极大潜力。研究结果为大豆分离蛋白基薄膜的生产应用提供参考。     

SPI凝胶颗粒制备及其Pickering高内相乳液特性研究

制备了大豆分离蛋白（Soy protein isolate,SPI）凝胶颗粒,并使用该颗粒制备了稳定的Pickering高内相乳液。通过粒径和ζ 电位测定、冷冻扫描电镜和光学显微镜观察以及外观分析,以流变特性为指标,对SPI凝胶颗粒和Pickering高内相乳液特性进行研究。结果表明,SPI凝胶颗粒的粒径和ζ 电位随pH值的变化而变化,当SPI凝胶颗粒pH值为4.0～5.0时,临近SPI等电点,ζ 电位的绝对值最小,此时凝胶颗粒相互聚集,不能成功制备稳定的高内相乳液。在pH值为 9.0时,大豆分离蛋白凝胶颗粒紧密结合在一起,呈凝胶网络状结构。在碱性条件下,蛋白质质量分数为1.00%、内相体积分数为78%～82%时,可以制备稳定的Pickering高内相乳液。通过增加内相体积分数,使大豆分离蛋白凝胶颗粒稳定的Pickering乳液体系分布更加均匀,不易发生聚集,形成更加致密稳定的多孔结构,且具有更强的弹性凝胶乳液特性。     

An isolate of Wheat streak mosaic virus from foxtail overcomes Wsm2 resistance in wheat

Wheat streak mosaic virus (WSMV) is an economically important pathogen of wheat (Triticum aestivum) causing major yield losses in regions where severe infection occurs. To detect the presence of any new virus or new WSMV isolates, green foxtail (Setaria viridis) plants exhibiting virus-like symptoms were sampled in a summer-fallowed wheat field at the Agricultural Research Center-Hays, Kansas State University, Hays, Kansas. These plants were tested serologically for four wheat viruses: WSMV, Triticum mosaic virus (TriMV), High Plains wheat mosaic virus (HPWMoV) and Foxtail mosaic virus (FoMV). Among 38 plant samples exhibiting virus-like symptoms, 29 contained WSMV as indicated by ELISA. Four isolates from samples with relatively strong reactions were transferred to healthy wheat seedlings by mechanical inoculation in a growth chamber for pathogenicity testing. Three isolates were avirulent to a wheat variety RonL, which contains Wsm2, a gene providing temperature-sensitive resistance to currently prevalent isolates of WSMV. However, one isolate, KSH294, was able to infect RonL and showed more virulence on two other varieties/lines containing Wsm2. Further sequence and phylogenetic analysis of KSH294 confirmed that this isolate displays a sequence homology with WSMV, but has sequence differences making it distinct from previously identified WSMV isolates included in the phylogenetic analysis.     

竹叶抗氧化物浸泡-乳清分离蛋白涂膜对冷藏富硒虹鳟蛋白质理化性质的影响

为从蛋白质水平解释竹叶抗氧化物浸泡-乳清分离蛋白涂膜对富硒虹鳟的保鲜机理,实验将鲜活富硒虹鳟去除头、内脏和表皮,切块后浸泡在1.0%的竹叶抗氧化物（AOB）溶液中（去离子水作为对照）,再进行乳清分离蛋白（WPI）溶液涂膜,25℃下鼓风吹干表面水分后置于4℃冰箱中贮藏1、4、7、10和13 d。测定鱼肉中肌原纤维蛋白和TCA-可溶性肽的含量、蛋白质的分子内价键,以及肌原纤维蛋白的总巯基含量、表面疏水性和二级结构,分析涂膜对冷藏富硒虹鳟蛋白质理化性质的影响。结果显示,冷藏期间,WPI组的肌原纤维蛋白含量和二级结构中β-折叠的含量显著高于对照组。冷藏1～7 d,WPI组的TCA-可溶性肽和二硫键含量以及表面疏水性指数（H₀）显著低于对照组,总巯基含量呈相反趋势,但随着冷藏时间的延长这些差异逐渐减弱。冷藏13 d时,WPI组与对照组无显著差异。3个实验组中,1.0%AOB+WPI组的肌原纤维蛋白、总巯基、氢键、二级结构中α-螺旋和β-折叠的含量在冷藏期间最高,H₀、TCA-可溶性肽、二硫键和二级结构中β-转角含量最低。WPI在鱼块表面形成一层薄膜,可...