鸡传染性鼻炎二价油乳剂灭活疫苗的近期免疫效力检验

应用３批鸡传染性鼻炎价油乳剂灭活疫苗进行了安全性和近期免疫效力检验,安全性试验采用１５只鸡进行,胸肌注射疫苗４￣５ｍＬ／只后,逐日观察,结果鸡只食欲、精神未见异常,２周后观察,注射部位未发现明显异常和病变。用该疫苗免疫（０．５ｍＬ／ｋｗ ）后的鸡只对Ａ型高致病力菌株的攻击保护率可达１００％,对Ｃ型高致病力菌株的攻击保护率为９３．３％。采用Ｂ－ＥＬＩＳＡ和ＳＰＺＡ对鸡群的抗体水平的评估表明该疫苗可激发产生较高的抗体水平。     

东北虎巴氏杆菌毒力基因toxA的克隆及同源性分析

通过对吉林市江南公园送检东北虎病例的病原分离鉴定,分离出多杀性巴氏杆菌,为进一步加强对该病的流行病学调查,并为准确诊断和治疗该病提供依据,实验对该株巴氏杆菌毒力基因toxA进行了研究。根据巴氏杆菌毒力基因toxA序列设计合成1对引物,以临床分离的虎源巴氏杆菌为模板,通过PCR技术,扩增出toxA基因片段。将长约526bp的toxA目的基因克隆到pGEM-T载体上,通过核苷酸序列测定,结果表明toxA基因序列与发表序列（X51512）的同源性为100%。流行病学调查显示,东北虎巴氏杆菌病的病原可能来自其食物（牛、羊肉等）。因此,在饲养过程中应加强检疫,切断巴氏杆菌病食源性传播途径。     

我国高效苏芸金杆菌菌株对玉米螟毒力的初步评比

本文以玉米螟为供试昆虫,采用规范化的生物测定方法对全国各地筛选的19个高毒力苏芸金杆菌菌株进行毒力评比.实验结果表明属于血清型H_(3a3b)的各菌株对玉米螟具有较高的毒力.以LD_(50)作为衡量各菌株的毒力指标选出了HD-1、鄂农3号、551和80-1等几个高毒力的菌株,为今后生产高效的苏芸金杆菌制剂提供了依据.     

IB(M41株)种毒代次和免疫原性的关系

评估不同代次IBV M41株种毒是否可以作为生产用种子。将M41株种毒用SPF胚连传8代,从中选出第3、第5、第7代,测定其EID50。并用此3代M41株鸡胚尿囊液制毒的油乳苗免疫易感鸡,以HI试验检测其抗体水平。3种疫苗免疫鸡均保护9/10以上,对照鸡全发病;对免疫后与免疫前HI抗体水平的比较表明,免疫后抗体平均滴度提高3倍以上。不同代次的M41毒株的免疫原性仍然保持良好,可以正常用来制造疫苗和建立种子批。     

猪瘟重组蛋白E2的兔体免疫保护试验

鉴于猪瘟病毒不能使家兔发病,但能使之产生免疫原性,而且猪瘟兔化弱度苗能在兔体的定型热反应.本研究选用家兔为试验模型,将自制的亚单位疫苗用弗氏佐剂乳化后免疫家兔,持续一定的免疫周期后,用猪瘟活疫苗(Ⅱ)攻击免疫及对照试验家兔.根据T淋巴细胞增殖试验、阻断ELISA及攻毒保护试验对所制备的抗原进行了全面的评价.结果表明,该免疫原具有良好的免疫原性,而且能保护免疫家兔为4/4.可以进行下一步的开发和利用价值.以期该疫苗能为猪瘟的防治做出贡献.     

低致病性禽流感H9N2病毒感染鸡群引起巴氏杆菌的内源性感染

摘要：目的 研究低致病性禽流感H9N2病毒感染鸡群的变化。方法 用107.4 EID50/0.1ml H9N2病毒,0.5ml/只,接种1月龄SPF鸡。结果 5日后引起鸡群发病,并引起一些个体发生死亡,剖检发现喉头充血、肺淤血,气囊膜增厚,皮下胶样浸润、出血,腺胃乳头出血,十二指肠出血。肝、脾、肾、肺常见有灰黄色坏死灶。无菌取肺组织做细菌培养时发现在血平板上有白色露珠状菌落,挑取菌落做碱性美蓝染色镜检发现两极浓染的杆状菌;经生化和PCR检验确认该菌属于多杀性巴氏杆菌。结论 低致病性禽流感H9N2病毒感染鸡群可引起巴氏杆菌的内源性感染,从而导致鸡群的高发病率与高死亡率现象。     

蛴螬乳状菌形态变化的研究

在研究乳状菌毒力时发现,作为乳状菌传统分类标准的前孢,其遗传结构是不稳定的,随着寄主变换而存在或消失,从而对乳状菌分类标准提出了疑义.由于形态变化引起了毒力改变,780—1菌株变化后,致病力明显提高.说明毒力大小并不取决于前孢有无,因此对前孢作用有了一个新的认识.     

鸡传染性法氏囊炎免疫失败原因浅析

鸡传染性法氏囊炎(IBD)是一种由双链双节段RNA病毒引起的雏鸡的一种急性接触性传染病.该病主要侵袭雏鸡的免疫中枢器官法氏囊,引起雏鸡的免疫抑制,使病鸡对大肠肝菌、腺病毒、沙门氏菌、鸡球虫等更易感,对马立克疫苗、新城疫疫苗等接种的反应能力下降,在养鸡场中可造成相当大的经济损失.目前,控制本病的主要方法仍是免疫接种,但由于各方面的原因,养禽户常遇到IBD疫苗免疫失败的问题.下面就鸡传染性法氏囊炎免疫失败的原因作一浅要分析,供同行参考.     

昆虫病原线虫共生菌对水稻恶苗病菌的抑菌活性及其抗逆性的研究

利用不同品系昆虫病原线虫的共生菌菌株对水稻恶苗病菌进行抑菌活性测定,得到一株抑菌效果良好的共生菌菌株NC34-1,抑菌圈平均半径为17.33mm,并对高毒力菌株的抗逆性(包括不同温度、紫外照射)进行了初步探索,结果表明,共生菌菌株Nc34.1在50℃高温下处理10min,其抑菌活性依旧很高;18W紫外线照射120min对共生菌NC34-1的抑菌活性的影响不明显.于LB培养基、160r/min、28℃培养40h时抑菌效果最佳.     

菌落聚合酶链反应检测支气管败血波氏杆菌

根据支气管败血波氏杆菌(Bordetella bronchiseptica) 鞭毛蛋白基因的上游序列设计1对引物Fla1和Fla2,采用菌落PCR方法扩增目的基因片段来检测支气管败血波氏杆菌。利用该方法成功的从8株支气管败血波氏杆菌中扩增出237 bp左右的特异性目的片段。特异性试验表明,该方法对大肠埃希菌、胸膜肺炎放线杆菌、多杀性巴氏杆菌、猪链球菌和副猪嗜血杆菌均无交叉性反应。灵敏性试验表明,将单个菌落稀释105倍利用此菌落PCR仍能扩增到相应的目的片段。结果表明建立的菌落PCR方法对支气管败血波氏杆菌的检测敏感性高、特异性强,可用于Bb感染的诊断和流行病学调查。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.