松苗立枯病的研究Ⅰ、分布损失、征状类型、病原、和栽培影响

松苗立枯病是东北地区针叶树育苗上的重要问题,其中以落叶松、樟子松、和红松等幼苗发病较重,油松和赤松等幼苗发病为轻。幼苗发病征状有土内腐死、猝倒、立枯、地上腐烂、和一、二年生大苗发生枯萎落叶等五个类型。诱致松苗发生侵染性立枯病的病菌,有 Rhizoctonia、Pythium 和 Fusarium等三种菌类,其中 Rhizoctonia 尤为主要。松苗立枯病发生的轻重与育苗措施有密切关系,地势低洼或位于山脚下坡的苗圃或苗床,一般发病较重。种子经雪藏混砂催芽处理后,能提早种子萌芽、出土和齐苗,有降低发病程度的作用。光照多少对幼苗发病有影响。根据苗圃的调查观察,全光育苗发病率低,遮蔭育苗发病率高;但在沈阳试验结果还不能证实这一点,相反的半遮蔭育苗要好些。     

基于PCV3-Cap蛋白间接ELISA检测方法的建立及临床应用

为了建立一种敏感和特异的猪圆环病毒3型(PCV3)抗体检测方法,对PCV3-Cap蛋白抗原表位预测发现其抗原表位多聚集在C端(羧基端),而N端前33氨基酸为核定位序列。以截断N端前120个氨基酸后的PCV3ORF2序列为靶基因,设计引物。以PCV3阳性病料为模板,PCR扩增截短的ORF2基因,并将其克隆至pET-30a载体构建重组质粒,并转染至大肠杆菌E.coli BL21感受态细胞,获得重组菌后选择最佳诱导表达条件,采用Ni-NTA亲和层析柱纯化表达产物。以纯化后的重组Cap蛋白作为包被抗原,建立PCV3间接ELISA (indirectELISA)诊断方法,并初步用于临床样品检测。结果:从阳性病料中扩增出大小为285bp的PCV3ORF2基因片段,重组质粒经双酶切和测序鉴定构建成功。采用1mmol·L-1 IPTG诱导,在37℃条件下培养6h重组菌,重组蛋白获最佳表达。Western blot结果表明,该重组蛋白与PCV3阳性血清具有较好的反应原性。ELISA的最佳包被抗原质量浓度为1μg·mL-1,待检血清最佳稀释度为1∶20,酶标抗体最佳工作浓度为1∶5 000。阳性判定值为S/P≥0.273。批内和批间系数均小于10%,表明该方法具有较好的重复性。PCV2阳性血清用本方法检测为阴性,表明该方法有较好的特异性。检测采集的439份临床猪血清,PCV3抗体阳性检出率为60.59%(266/439)。结果表明,本研究建立了一种快速、简便、敏感、特异的猪圆环病毒3型(PCV3)抗体检测方法。     

基于PCA的农机购置补贴绩效评价研究

针对农机购置补贴绩效评价过程中存在的数据统计繁杂、人工处理耗费时间长、计算结果易出错、不能及时得到数据结果等问题,本文提出了一种基于PCA进行绩效评价的新方法,并与常用的因子分析法及图表比对法进行了结果比对。结果显示,该方法结果准确,且前三主分量累积比率达到83.16%接近85%(常用阈值),可用前三主分量代替整体研究失分率。经过在近两年的绩效考评工作中实践验证,该方法操作简便,结果简明,特别在数据量庞大情况下该法优势更加明显,适用于农机购置补贴绩效考核评价。     

On the fracture morphology in wood

Summary Failure forms caused by axial ultimate compression stress in three softwood and nine hardwood species and in model specimens made of wood, paper and plastics are described. Three categories of failure forms are distinguished: 1. Wood characteristic failure forms are connected with the general anisotropic structure of the wood. 2. Failure forms specific to the species are modifications of the first category arising from predominant anatomical structures. 3. Modifications of the failure forms are also induced experimentally. The interdependence among the anatomical structure, strength characteristics and failure forms of the wood specimens are examined by statistical methods. The structure cipher introduced in this paper, as a numerical characteristic of the anatomical features of the wood species, is seen to be the most important influencing factor as regards the intensity and pattern of the fracture, followed in second and third place by the geometry of the specimen and its specific gravity. Specimen volume and other factors are shown to have only a marginal influence on the fracture morphology.The strength tests were carried out as part of a diploma thesis by K. Buchmüller. Also the assistance of E. Risi in measuring and evaluating is gratefully acknowledged     

非洲猪瘟病毒无标签p30-ELISA抗体检测方法的建立及应用

非洲猪瘟(African swine fever, ASF)是由非洲猪瘟病毒(African swine fever virus, ASFV)引起猪的一种急性、热性、出血性、高度接触性传染病,临床症状以败血症、皮炎和关节炎为特征,高发病率和高死亡率。为建立临床检测ASFV抗体的间接ELISA检测方法,本研究扩增了ASFV-CP204L基因,通过pET-30a原核表达系统表达p30蛋白,使用Ni-NTA纯化表达产物,通过肠激酶切除外源性蛋白,得到无His-组氨酸标签的p30蛋白,以此为诊断抗原,建立间接ELISA方法。结果显示：表达的无标签p30重组蛋白大小约为30 ku,与ASF阳性猪血清具有较好的反应原性;确定ELISA抗原包被浓度为1 μg·mL^-1,根据ROC曲线下面积确定S/P值>0.398判定为阳性,批内、批间变异系数均<10%;与PCV2、CSFV、PRV-gE、PRRSV阳性血清无交叉反应与INGENASA商品化试剂盒总符合率为97.78%。用该方法分别检测标准阳性血清、动物感染试验血清和收集的区域性临床血清644份,该方法最低可检测到1∶512倍稀释的标准阳性血清样品;检测感染动物血清,其中80%(4/5)的试验动物在第10天抗体为阳性。644份临床猪血清样品中抗体阳性率为7.61%,其中,母猪、后备母猪、仔猪、保育猪和育肥猪抗体阳性率分别为3.03%、0%、4.94%、7.55%和28.7%。本试验建立的ASFV-p30间接ELISA方法具有良好的特异性、灵敏度和重复性,可应用于ASFV的抗体检测,为ASF的诊断和流行病学调查提供了技术手段。     

Glutathione Transferase Isozymes Involved in Insecticide Resistance of Diamondback Moth Larvae

In addition to the three glutathione transferase (GST) isozymes already identified in diamondback moth larvae, Plutella xylostella (L.), a fourth one, GST-4, was purified from a teflubenzuron (TFB)-resistant strain. This GST isozyme was similar to GST-3 in terms of biochemical and toxicological properties. GST-4, a homodimer with a subunit molecular mass of 26.6 kDa and a pI of ca. 8.9, displayed even stronger substrate preference than GST-3 for 1,2-dichloro-4-nitrobenzene and several organophosphorus insecticides, i.e., parathion, methyl parathion, and paraoxon. These two proteins were highly immunorelated and shared at least the first eight amino acids at the N-terminus. Immunoblotting analysis indicated that polyclonal antiserum raised against GST-3 cross-reacted with GST-1 and GST-2 at least 40-fold less intensely than with the antigen. Using this antiserum as probe, higher amounts and greater variations of GST-3/GST-4 were observed in larvae of a methyl parathion- and a TFB-resistant strain compared with a susceptible and a fenvalerate-resistant strain. Among the six lepidopterous insects examined, only Spodoptera exigua larvae clearly had proteins immunorelated to GST-3/GST-4 of diamondback moth. No such cross-reactivity was observed in Musca domestica, Drosophila melanogaster, and Aedes aegypti.     

An immunohistochemical study of the gastrointestinal endocrine cells in the C57BL/6 mice

The regional distributions and relative frequencies of some gastrointestinal endocrine cells in the eight portions (fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum) of the gastrointestinal tract of C57BL/6 mouse was studied with immunohistochemical method using seven types of specific anti-sera against chromogranin A (CGA), serotonin, somatostatin, human pancreatic polypeptide (HPP), glucagon, gastrin and cholecystokinin (CCK)-8. In this study, all these seven types of immunoreactive (IR) cells were identified. Most of these IR cells in the intestinal portion were generally spherical or spindle in shape (open-type cell) while cells showing round in shape (closed-type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies were varied according to each portion of gastrointestinal tract. CGA-IR cells were demonstrated throughout the whole gastrointestinal tract and they showed most predominant in the pylorus and duodenum. Serotonin-IR cells were detected throughout whole gastrointestinal tract and they showed highest frequency in the stomach and colon. Somatostatin-IR cells were demonstrated throughout whole gastrointestinal tract except for large intestine and showed highest frequency in the fundus. HPP-IR cells were found in the fundus with rare frequency. Peculiarly, glucagon-IR cells were restricted to the fundus, ileum and colon with a few frequencies. Gastrin-IR cells were restricted to the pylorus with numerous frequency and CCK-8-IR cells were observed in the pylorus, duodenum and jejunum with numerous and/or a few frequencies, respectively. In conclusion, some peculiar distributional patterns of gastrointestinal endocrine cells were found in C57BL/6 mouse.     

Field trials on the prophylaxis of intramammary infections in pregnant heifers

The study was carried out in 5 farms on 174 pregnant heifers. Clinical examination of the udder and bacteriological tests of quarter secretion were performed between the 8th and 3rd week before parturition, and then the animals were divided into a control group (64 heifers) and 3 experimental groups and immediately treated. A group of 32 experimental heifers was injected once with antioxidants (Vitamin A--600,000 i.u.; Vitamin D3--200,000 i.u.; Vitamin E--1.5 mg/kg b.w., Selenium--0.022 mg/kg b.w., i.m.). The next group (26 heads) was intramammary infused with antibiotic DC product (cloxacillin). Heifers from last experimental group (52) were injected with lysosyme dimer in a single dose of 0.02 mg/kg b.w. Clinical and bacteriological examinations were made during the first week after calving. The presence of bacteria was found in secretion of 22.6-38.9% udder quarters in 56.2-71.2% of pregnant heifers. The number of infected quarters (cows) did not change distinctly in the first week after calving except the lysozyme dimer group, where a decrease by 30% was noted. The percentage of quarters with elevated somatic cell count was higher in antibiotic DC group and closely similar in the other groups. None of examined methods showed an acceptable prophylactic effect. Clinical mastitis cases during first week after parturition were mostly caused by Escherichia coli, Staph. chromogenes, Staph. simulans, Staph. aureus, Staph. hyicus, Str. uberis, Str. acidominimus and Enterococcus faecalis.