鸡传染性喉气管炎和鸡痘弱毒在鸡胚皮肤细胞上同时增殖的研究

根据喉、痘病毒易在上皮细胞中增殖这一共同特点,分别进行鸡传染性喉气管炎、鸡痘弱毒适应鸡胚皮肤细胞(CES)和对CES致细胞病变效应(CPE)试验.掌握其规律之后,选择病变快、含毒量高的第三代喉气管炎细胞毒(LTVCES_3)及第三代鸡痘细胞毒(APVCES_3)以1:1的比例同时接种CES细胞,并分别用鸡胚和细胞对喉、痘鸡胚毒、CES细胞毒及混合细胞毒进行毒价测定.喉、痘细胞毒的毒价平均高于同株鸡胚毒0.7—1个滴度,混合细胞毒毒价平均低于同株细胞毒0.25—0.3个滴度而高于鸡胚毒0.5—0.7个滴度,从而达到在同一细胞上同时增殖喉、痘病毒之目的,为研制喉、痘二联苗探索了新途径.     

Ⅰ型鸭肝炎病毒（DHV-Ⅰ）在鸡胚中的增殖及感染力的测定

摘要：将Ⅰ型鸭肝炎病毒（DHV-Ⅰ）接种9日龄SPF鸡胚尿囊腔（0.2 mL/胚）进行增殖,制备鸡胚成纤维细胞（CEF）,并分别运用CELD50法和TCID50法测定DHV的感染力。结果表明,DHV-Ⅰ在SPF鸡胚内成功增殖,致死鸡胚具有典型临床症状和体表特征,所增殖病毒的CELD50和TCID50分别为10-5.6/0.2 mL和10-5.12/0.1 mL。     

麻花鸡副黏病毒ZH-1株F基因真核表达载体的构建

将麻花鸡副黏病毒ZH-1株毒种接种于11日龄SPF鸡胚,收集48～96h死亡的鸡胚尿囊液.参考已发表的鸡源副黏病毒F基因序列,设计并合成了一对特异性引物,用以扩增麻花鸡副黏病毒ZH-1株F基因,预期扩增的F基因片段包含完整的开放阅读框.通过RT-PCR扩增出麻花鸡副黏病毒ZH-1株F基因片段,琼脂糖凝胶电泳回收、纯化,得到F基因片段,经EcoR I和Sal I消化,将F基因克隆进入PCI-neo载体,转化大肠杆菌DHSa,挑选菌落,经限制性核酸内切酶Sal I和EcoR I双酶切及PCR鉴定,结果证明重组真核表达载体PCI-neo-F构建成功,为下一步在哺乳动物细胞vero细胞中表达打下良好的基础.扩增的F基因测序后,与其他禽副黏病毒1型F基因进行系统发育树的分析比较,为阐明麻花鸡副黏病毒ZH-1株的遗传背景奠定了基础.     

鸡传染性支气管炎病毒HN104株的鉴定及S1基因的分子特征

2010年4月从河南省某疑似患鸡传染性支气管炎鸡场中分离到一株病毒。通过SPF鸡胚致侏儒实验,鸡红细胞凝集试验,干扰新城疫病毒增殖试验和RT-PCR试验确认该病毒为一变异的鸡传染性支气管炎病毒。该病毒尿囊液凝集鸡红细胞的HA价为0,经胰酶处理后为27;EID50（鸡胚半数感染量）为10－5.5/0.1 mL;能够显著干扰鸡新城疫病毒La Sota株在鸡胚中的增殖;动物回归试验结果显示该病毒可致SPF雏鸡出现肾脏肿大,呈花斑肾。其S1基因全长为1617 bp,经序列分析发现与鸡传染性支气管炎疫苗Massachusetts株、T株、4/91株亲缘关系较远低于78%。     

表达鸡白细胞介素18重组禽痘病毒的构建及其表达产物生物学活性的检测

为构建表达鸡IL-18的重组禽痘病毒，将含痘病毒启动子IP2EP2驱动的鸡，IL-18基因插入到禽痘病毒转移载体pSY681中，获得重组转移载体pSY681／ChIL-18。将pSY681／ChIL-18转染已感染亲本禽痘病毒S-FPV-017株的鸡胚成纤维细胞，使其在鸡胚成纤维细胞内与禽痘病毒基因组发生同源重组，产生表达鸡IL-18的重组禽痘病毒rFPV-ChIL-18。在含有X—gal的营养琼脂培养基上进行蓝斑筛选后，对重组病毒rFPV-ChIL-18又进行了多次蚀斑克隆。以重组禽痘病毒DNA为模板，利用鸡IL-18基因特异引物进行PCR，扩增出1条约0．6kb的带。收集含鸡IL-18蛋白的细胞上清液进行MTT试验，表达的产物能明显提高鸡淋巴细胞的转化率。     

影响蛋鸡产蛋下降的主要因素

一、饲料因素1.日粮中钙含量不足。一只蛋鸡产蛋期每天约需钙3～3.5克。在产蛋期必须选择含钙量较高的饲料,且补充的钙盐有利于鸡吸收。添加方法及时间:当鸡群中见第一枚蛋时或开产前2周(约18日龄),为照顾已开产母鸡,日粮中可加入一些贝壳粉,让开产鸡自由采食,到鸡群产蛋率达5%时再改换为产蛋饲料。     

不同培养液对鹅胚胎体外培养的影响

为了探讨不同培养液对鹅胚胎体外培养的影响,本试验分别用鸡、鸭、鹅3种稀蛋白作培养液对90只鹅胚进行体外培养。结果表明：用鹅稀蛋白作培养液优于鸡稀蛋白和鸭稀蛋白。鹅稀蛋白组在第6、15天时鹅胚存活率显著高于鸭稀蛋白组(P<0.05),鹅胚存活率在第6、15天分别为33.33%、20.00%;在第31天时鹅稀蛋白组鹅胚存活率为3.33%,其他两组为0。综上所述,鹅胚体外培养效果因培养液的不同而不同,在鸡、鸭和鹅稀蛋白3种培养液中,以选用鹅稀蛋白为宜。     

浅谈鸡传染性法氏囊病的诊断与防治

正鸡传染性法氏囊病是由传染性法氏囊病毒引起的一种急性、接触性、传染性疾病。一、病毒特性鸡传染性法氏囊病病毒属于双股RNA病毒科,禽双股RNA病毒属,病毒含单层衣壳,无囊膜,病毒粒子直径55～65纳米。该病毒能在鸡胚内繁殖,7～8日龄胚做卵黄囊接种,或9～11日龄胚做绒毛尿囊膜或尿囊腔接种,接种后鸡胚通常在感染5天左右死亡,出现胚体发育停滞,水肿及出血。病毒在外界环境较为稳定,圈舍内可长期存     

新城疫病毒诱导黄粉虫抗病毒肽的效果分析

目的：观察鸡新城疫病毒（NDV）诱导黄粉虫是否产生抗鸡新城疫病毒肽。方法：先用鸡胚培养鸡新城疫病毒以扩增病毒,然后提取病毒液备用,接着用鸡新城疫病毒液接种刺伤黄粉虫幼虫,2～3天后提取黄粉虫体内的抗病毒物质,测定其血凝效价和鸡新城疫病毒诱导鸡胚发病抑制试验结果。结果 ：黄粉虫抗病毒肽在血凝抑制试验中的效价为1∶64;在鸡新城疫病毒诱导鸡胚发病抑制试验中有一定效果,但不明显。     

食品鸡蛋及死胚蛋中沙门氏菌的检测

为了解我国食品鸡蛋和死胚蛋(毛蛋)中沙门氏菌的感染情况,分别对130颗食品蛋的蛋壳表面、蛋内容物以及70颗完整死胚蛋(毛蛋)和66颗破壳死胚蛋的肝、肠、卵黄囊进行了沙门氏菌的检测。结果表明,在所检测的130颗食品鸡蛋中蛋壳表面及蛋内容物细菌的检出率分别为76.92%和4.83%,其中沙门氏菌的检出率分别为0.76%和0;70颗完整毛蛋肝、肠、卵黄囊细菌的检出率分别为:47.1%,42.9%,48.6%,其中沙门氏菌的检出率为:4.29%,4.29%,1.42%;66颗破壳毛蛋中肝、肠、卵黄囊细菌的检测率分别为:83.3%,93.9%,84.8%,其中沙门氏菌的检出率为:19.7%,18.2%,16.7%。研究表明,我国市场上鸡蛋的沙门氏菌检出率较低,但为了防止蛋壳表面的细菌和沙门氏菌渗入蛋内容物而对人类的健康造成危害,有必要进行洁蛋加工。对于毛蛋中沙门氏菌的检测,发现破壳毛蛋沙门氏菌的检出率显著高于完整毛蛋。因此,蛋壳在防止沙门氏菌入侵的过程中起到了重要作用。此外,由于毛蛋中沙门氏菌的检出率较高,在鸡蛋生产过程中需要加强孵化场的环境控制以降低雏鸡感染沙门氏菌所造成的危害。     

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.     

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.     

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.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

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...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Breeding forage grasses for organic conditions

Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions. Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture.     

The performance of double or mixed pollinations with compatible and self-incompatible or incongruous pollen of pear and apple

Summary Six pear and five apple trials were carried out to ascertain the outcome of combinations of compatible pollen (C) with self (S) or incongruous pollen (I) as to the pollination index (PI=seeds/pollinated flower). The PI of the mixture C+I (1:5) was consistently depressed as compared to that of the control C. The results of the double pollinations S/C and I/C were affected by the temperature at pollination; their PI's at <15°C were twice as high as those at >15°C, being well above and below the PI of C in the former and latter case respectively. The opposite was true for the C/S combination, the PI of which increased with the pollination temperature; the PI of C/I did not differ much from the PI of C, irrespective of temperature. The conclusion was reached that the interaction previously and presently found between compatible and self-incompatible pollen also exists to a fair extent between compatible and incongruous pollen. However, in pear neither the mentor nor the pioneer pollen technique proved to aid its hybridization with apple, the formation of self seed was not observed either. In apple the production of apple × pear hybrids was likewise doubtful, but the double pollinations S/C and C/S formed 4–10% self seed.