一株对玉米螟高毒力的苏云金芽孢杆菌的鉴定及其杀虫活性

从田间土壤中收集并分离获得野生菌株,进行菌体、伴孢晶体形态学观察及分子生物学鉴定,测定其对玉米螟及水稻二化螟的室内生物活性。结果表明,该菌株革兰氏染色阳性,产生的伴孢晶体形状多为不规则形。16S rDNA序列与苏云金芽孢杆菌属的BMB 171同源性达99%,鉴定为苏云金芽孢杆菌,命名为JN002。该菌株对亚洲玉米螟具有较高毒力,对水稻二化螟毒性不及玉米螟,对黏虫几乎无毒力。该菌株是1株对亚洲玉米螟具有较强毒力的苏云金芽孢杆菌新菌株,同时也具备防治水稻二化螟的潜力。     

Development of a rapid biological assay for determination of potency of Newcastle disease vaccine (strain I-2)

A rapid biological assay based on incubation time has been developed for determination of the potency of Newcastle disease virus strain I-2 vaccine. It is based on the observation that the interval between inoculation and the first detection of haemagglutinin (HA) depends on the titre of the vaccine inoculated. Chicken embryonated eggs were inoculated with different titres (10⁹, 10⁶ and 10³ EID₅₀/0.1 ml) of vaccine and incubated for 24 h. At hourly intervals, 5 eggs from each vaccine titre were tested for the presence of HA. The results showed that the HA activity was detected from 5, 11 and 15 h after inoculation with vaccine doses of 10⁹, 10⁶ and 10³ EID₅₀, respectively. On the basis of these results it is suggested that if there is no HA detected from 5 to 11 h after inoculation of eggs with the vaccine virus, the vaccine should not be used to vaccinate chickens as it might have an infectivity titre of less than 10⁶ EID₅₀/0.1 ml, which is equivalent to the recommended single chicken dose. It is concluded that measuring the time between inoculation of the vaccine virus and the onset of HA activity might provide an estimate of the titre of the vaccine within 24 h.     

Assessment of longitudinal systolic function using tissue motion annular displacement in healthy dogs

Introduction

Left ventricular systolic function is one of the main parameters studied in echocardiography. Longitudinal systolic function, however, is less commonly evaluated in routine examinations but may provide early information on systolic dysfunction. The movement of the mitral annulus toward the apex has already been determined as a method for evaluation of longitudinal systolic function in dogs, but the study of this movement by speckle tracking with the tissue motion annular displacement (TMAD) technique has not yet been evaluated.

Left atrial deformation and phasic function determined by two-dimensional speckle-tracking echocardiography in dogs with myxomatous mitral valve disease

Introduction

Left atrial (LA) function can provide useful information in dogs with myxomatous mitral valve disease (MMVD). Recently, we have demonstrated the feasibility of measuring LA longitudinal deformation using speckle-tracking echocardiography (STE) to estimate LA function in healthy dogs. Whether LA strain and strain rate variables provide additional information about LA function and clinical cardiac status in dogs with MMVD remains unexplored.

中国北方春大豆区大豆花叶病毒株系的鉴定与分布

从我国北方春大豆区的黑龙江、吉林、辽宁、内蒙、河北承德以及北京采集典型症状的大豆叶片病样,经Top-Crop离体叶单斑分离以及DAS-ELISA抗血清免疫鉴定,共获得112个SMV阳性反应分离物.根据112个分离物在合丰25、文丰5号、诱变30、8101、铁丰25、Davis、Buffalo、早熟18、广吉、科丰1号、齐黄22共11个鉴别寄主上的症状反应,将我国北方春大豆区的SMV分成8个株系群.各株系群所占比例分析表明,北方春大豆区以SC-11株系群为主,其次为SC-8,各占病样总数的比例分别为51.7%和17.9%,SC-11和SC-8分别在黑龙江和辽宁分布最广,占当地株系群的比例分别为67.8%和75.0%.与以往株系划分系统的初步比较表明,SC-11与东北原1号株系群,SC-12和SC-16与东北原2号株系群,SC-4、SC-7、SC-8、SC-13和SC-17与东北原3号株系群在鉴别寄主上的反应相似.SC-16和SC-17为2个新发现的株系群.     

野生桑黄菌种分离与培养特性研究初报

以新鲜野生桑黄子实体为材料,采用组织分离法获得纯菌株。该菌株的培养特性研究结果表明,桑黄菌丝生长的最适温度为28℃,最适pH为6.5,最适碳源是葡萄糖,最适氮源是蛋白胨,最适栽培培养基是鲜桑树枝木段培养基。     

一种适宜秸秆栽培的金针菇菌株筛选方法

以一株野生黄金针菇菌株为试验材料,研究了在试管内进行适宜秸秆栽培的金针菇菌株的筛选方法,对栽培的黄金针菇进行组织分离和孢子分离,并对分离后的菌株进行了栽培试验。结果表明：在密闭试管内以秸秆为栽培基质栽培黄金针菇可以顺利出菇,继而进行的组织分离与孢子分离,操作方便,成功率高,可用于适宜秸秆栽培的菌株初步筛选。     

羊肚菌菌丝体生长特性及菌核培养特征的初步观察

对两种野生羊肚菌菌株M1和M2在不同培养基上菌丝生长及菌核产生的特征进行了初步观察。结果表明,M1与M2相比,前者菌丝的生长势强;VB1可促进菌丝体和菌核的生长;菌核的形成与否及形成的早晚可作为鉴别菌株的标志之一     

Analytical study of turgor pressure in apple and potato tissues

Mechanical injuries are the main cause of damage (such as bruising) and loss of quality of fruit and vegetables, occurring mainly from mechanical forces during compression, vibration and impact loads. Apples and potatoes are susceptible to external and internal pressures, which causes bruising and fracture in soft tissues. The study of turgor pressure and the compressive stiffness of apple and potato tissues is essential to understand their fracture strength against external and internal pressures. In the present study, a generalized form of a strain energy function is proposed, and a relation between turgor pressure and stretch ratio is developed by considering its appropriate form. It is considered that the tissues are isotropic, incompressible, homogeneous, and show hyperelastic behavior. The Levenberg–Marquardt algorithm was used for regression analysis to calibrate the material constants by correlating predicted and experimental values of turgor pressure and stretch ratio for apple and potato tissues. A good fit of the developed relation to experimental data was obtained with the coefficients of determination of 98.02% for apple and 98.0% for potato.     

玉米螟高毒力白僵菌菌株紫外线诱变选育

对自然选育、综合性状表现较好的白僵菌BC6菌株进行紫外线诱变处理,获得产孢量高于亲本菌株的突变菌株4株(Z01、Z09、Z18、Z19)。突变菌株经继代培养,产孢量及产孢特性表现稳定,每代突变体菌株的产孢量均显著高于对应代数的对照亲本菌株,诱变菌株没有回复亲本菌株的表现。经生物测定,菌株Z19和Z09致病力高于对照。Z19菌株校正死亡率高于对照10个百分点以上,差异极显著。