10个新疆梨品种开花生物学及果实品质特征研究

了解新疆梨品种的开花生物学及果实品质特征,为其合理利用提供数据参考。在10个新疆梨品种的生殖生长期,对开花物候期、花部特性、花粉特性及果实品质特性等进行测定对比分析。结果表明:除‘艾温切克’‘库尔勒黄酸梨’外,其他8个品种花期一致,但果实成熟期有明显差异;‘库尔勒香梨’与其他品种的花器官特征无明显差异;‘绿梨’‘阿克苏句句梨’的花粉活力较强、单花药花粉量较多;‘艾温切克’‘绿梨’等4个品种的单果重较大,显著大于‘库尔勒香梨’;‘艾温切克’的果实硬度最小,与‘库尔勒香梨’无显著差异;‘艾温切克’‘绿梨’的可溶性糖、可溶性固形物、维生素C含量均较高,与‘库尔勒香梨’无显著差异或显著高于‘库尔勒香梨’。综上,‘绿梨’‘阿克苏句句梨’的花期与‘库尔勒香梨’重叠,花粉量较多、萌发率最高,花器官特征与‘库尔勒香梨’接近,可作‘库尔勒香梨’的备选授粉树;‘艾温切克’‘绿梨’的果实品质及口感好、果实成熟期早,且果皮颜色与其他品种有明显差异,可作为优良育种材料。     

拉枝角度对中矮1号矮化中间砧库尔勒香梨光合荧光参数的影响

【目的】研究不同拉枝角度对中矮1号矮化中间砧库尔勒香梨光合及叶绿素荧光特性的影响,为矮砧密植库尔勒香梨幼树整形栽培最适宜的拉枝角度提供理论依据。【方法】以杜梨为基砧,中矮1号为中间砧木的5年生库尔勒香梨为材料,采用不同拉枝角度(40°、60°、80°、100°)4个处理,测定并分析不同拉枝角度下库尔勒香梨的光合特性和叶绿素荧光特性差异。【结果】不同拉枝角度处理下中矮1号矮化中间砧库尔勒香梨的净光合速率(P_n)日变化曲线均呈“双峰”型,存在明显的光合午休现象。随着拉枝角度的增大,库尔勒香梨的光合参数也随着增大,但当拉枝角度过大,超过80°时,树体光合作用则会受到抑制。在80°拉枝处理下,库尔勒香梨的光合参数P_n、气孔导度(G_s)、细胞间隙CO ₂浓度(C_i)和蒸腾速率(T_r)日均值均高于其他3个处理,P_n日均值最高可达10.04 μmol/(m²·s),P_n、C_i和T_r日均值与其他处理存在显著性差异,实际光化学效率(Φ_PSⅡ)、光化学淬灭系数(C_qp)、非光学淬灭系数(C_NPQ)和PSII电子传递速率(R_ET)日均值最高。【结论】库尔勒香梨在80°拉枝角度时光合作用最强,受光抑制较弱,80°拉枝角度可作为中矮1号矮化中间砧库尔勒香梨幼树整形栽培的较适宜拉枝角度。     

5个梨品种枝叶生长与开花结果特性比较

【目的】研究新疆库尔勒地区5个梨品种的花期生物学、新梢生长及果实品质特征,为该地区库尔勒香梨栽培过程中辅栽品种选择、授粉树配置及果实品质评价提供科学参考。【方法】以库尔勒香梨为对照,库尔勒香梨同胞家族中的雪香、新梨7号、玉露香和红香酥4个梨品种为供试品种,采用人工调查及测定果实外在、内在品质的相关指标及主成分分析方法,研究不同梨品种的花期生物学、新梢生长及果实品质特征。【结果】雪香花粉量及花粉活性分别为4 000粒和48.52 ％,且显著高于其它品种,自然授粉坐果率高,达54.40 ％。5个梨品种新梢生长均从4月30日开始进入快速生长。新梨7号糖酸比为6.71,VC含量为25.84,显著低于试验对照,但其属于早熟品种;雪香糖酸比为11.31,与试验对照相差不大;玉露香糖酸比高于库尔勒香梨,VC、可溶性固形物含量与对照相近。新梨7号和雪香两个品种果实品质较为相似。【结论】选择雪香、新梨7号和玉露香作为库尔勒香梨的辅栽品种。     

Serologic detection of experimental Salmonella enteritidis infections in laying hens by fluorescence polarization and enzyme immunoassay

Detection of infected poultry flocks is essential for controlling eggborne transmission of Salmonella enteritidis to humans. The present study evaluated the detection of antibodies in the sera of experimentally infected chickens by a fluorescence polarization assay with a tracer prepared from the O-polysaccharide of S. enteritidis and an enzyme-linked immunosorbent assay (ELISA) with an S. enteritidis flagellin antigen. In two trials, groups of specific-pathogen-free laying hens were infected orally with either 10(6) or 10(8) colony-forming units (CFU) of S. enteritidis (phage type 13a) or with 10(8) CFU of Salmonella typhimurium. Serum samples were collected before inoculation and at five subsequent weekly intervals. Both assays successfully detected the majority of hens infected with S. enteritidis at either dose level, but they also identified a substantial number of hens infected with S. typhimurium as seropositive. The fluorescence polarization test detected S. enteritidis infection significantly more often and cross-reacted with sera from hens infected with S. typhimurium significantly less often than the ELISA. The fluorescence polarization assay also offered advantages in terms of speed and methodologic simplicity.     

Fluorescence polarization assay for the detection of antibodies to Mycobacterium bovis in bovine sera

The performance of a fluorescence polarization assay (FPA) that detects antibodies to Mycobacterium bovis in bovine sera is described. The FPA reported here is a direct binding primary screening assay using a small polypeptide derived from the M. bovis MPB70 protein. A secondary inhibition assay confirms suspect or presumed positive samples. Specificity studies involved five different veterinary laboratories testing 4461 presumed negative bovine samples. FPA specificity was 99.9%. The FPA was used to identify herd status as either M. bovis infected or non-infected. Herd surveillance studies (nine herds) were performed in Mexico and South Africa. The FPA had a specificity of 100% (two negative herds), and correctly identified six of seven infected herds. Finally, sera from 105 slaughter animals that had gross lesions in lymph nodes similar to those seen with bovine tuberculosis were tested by the FPA. Thin sections from the associated formalin-fixed paraffin-embedded samples of lymph nodes were stained using hematoxylin and eosin (H&E) for morphologic examination and using the Ziehl-Neelsen (ZN) method for detection of acid-fast bacilli. Of the 105 animals, 78 were classified as TB suspect based on lesion morphology, 21 were positive by ZN, 9 were positive by FPA and 13 were positive by PCR for the tuberculosis group of Mycobacterium. Among the 21 ZN positives, 11 (52.4%) were PCR positive. Among the 9 FPA positives, 8 (88.9%) were PCR positive. For the 13 PCR positives, 8 (61.5%) were FPA positive and 11 (84.6%) were ZN positives. These results show that use of the FPA for detection of M. bovis infection of cattle has value for bovine disease surveillance programs.     

Evaluation of student attitudes to cooperative learning in undergraduate veterinary medicine

RATIONALE FOR THE STUDY: Recent studies have demonstrated that collaborative or cooperative learning (CL) provides students and teachers with a variety of advantages over traditional instructional methods. To explore the possibility of introducing CL into the veterinary undergraduate curriculum on a larger scale-to facilitate the development of professional competencies-a cooperative learning assignment (CLA) was introduced into the fourth year Bachelor of Veterinary Medicine and Surgery (BVMS) degree course at the University of Glasgow. An evaluation was carried out as a basis for optimizing subsequent CL activities in the undergraduate course. METHODOLOGY: Evaluation of student attitudes to the CLA was conducted using pre- and post-task questionnaires and a focusgroup discussion involving student representatives from several of the small groups. Quantitative questionnaire data were imported into SPSS and a statistical test was used to identify any significant shifts in student attitudes. RESULTS AND CONCLUSIONS: Analysis of the quantitative questionnaire results indicates that students-who regarded themselves generally as team players rather than competing individuals-had few concerns before or after the CLA. There were some significant shifts (negative and positive) in response to some of the questions, but generally the results were encouraging. However, a number of issues emerged from the focus-group discussion with regards to the administration of CL and matching students' expectations to their experiences. In particular, students need to be adequately informed at the outset about the CL process and about how it will be assessed, have access to the required facilities, and be comfortable with learning different skills sets from those their peers are learning. Staff facilitators require adequate guidance on what they are expected to contribute to the CL process.     

Development of latex agglutination test with recombinant NcSAG1 for the rapid detection of antibodies to Neospora caninum in cattle

Neospora caninum, an apicomplexan protozoan parasite, is recognized as a major cause of abortion in cattle. Surface antigen 1 of N. caninum (NcSAG1) is an important immunodominant candidate for the development of a diagnostic reagent for neosporosis. The present study describes the development and evaluation of a latex agglutination test (LAT) with recombinant NcSAG1 (rNcSAG1) for the detection of antibodies to N. caninum in cattle. The rNcSAG1 gene was cloned in pET-28a and protein was expressed in Escherichia coli BL21 (DE3). Carboxylated latex particles were coated with rNcSAG1 and the degree of agreement between LAT and a commercial enzyme-linked immunosorbent assay (iscomELISA) was evaluated by using of 164 serum samples. Twenty-two (13.4%) and 23 (14.0%) of samples were positive for antibodies to N. caninum by LAT and ELISA respectively. Eighteen of 23 ELISA-positive samples were positive according to the LAT and a substantial agreement (κ=0.77) was found between the results of LAT and ELISA. The results indicated that the LAT with rNcSAG1 would be a rapid, simple, relatively inexpensive and suitable diagnostic test for detection of specific antibodies in N. caninum infection under field conditions. Improvement in purification of rNcSAG1 can reduce probable false positive reactions and so increase the degree of agreement between the LAT and ELISA.