鸡大肠杆菌菌苗免疫原性的研究

用不同的时间和温度培养鸡致病性Ｅ．ｃｌｏｉ，４１℃，４８ｈ和３７℃，７２ｈ均可见众多的菌毛，而在４１℃，４８ｈ的条件下，活菌数及菌毛产量均高于３７℃，７２ｈ的。用提取的菌毛、超声波灭活的Ｅ．ｃｏｌｉ制成油乳苗免疫鸡，用同型Ｏ５０菌株经后胸气囊攻毒后，免疫鸡无死亡，而氢氧化铝胶菌苗免疫组的死亡率为２０％，未免疫攻毒组死亡率为３３．３％。各免疫组幸存鸡平均病变级数均显著低于未免疫攻毒组（Ｐ＜０．０１）。Ｅ．ｃｏｌｉ的菌毛剂量为１２０μｇ／只和８０μｇ／只的油乳苗免疫组，在免疫后用同型Ｏ５０菌株攻击时，保护指数最高；当剂量为６０μｇ／只时，保护指数较高；而用３０μｇ／只的剂量免疫时，免疫无效。雏鸡经含菌毛、不含菌毛的Ｅ．ｃｏｌｉ超声波灭活油乳苗和福尔马林灭活油乳苗免疫后用同型Ｏ５０菌株攻毒，含菌毛菌苗的保护指数均高于相应的不含菌毛菌苗的；超声波灭活菌体的油乳苗免疫组幸存鸡平均病变级数低于福尔马林灭活菌体的油乳苗免疫组的；各免疫组与未免疫攻毒组幸存鸡平均病变级数差异极显著（Ｐ＜０．０１）。     

广西鸡大肠杆菌的分离与鉴定

从广西6个代表性鸡场分离出132株大肠杆菌,分离率平均为37.82％,其中81.82％的菌株分离自2～8周龄的鸡;经血清学鉴定,流行的血清型主要有11种,其中O_(50)、O_(133)、O_(15)、O_(90)、O_(146)、O_(92)及O_(84)等7种属首次报道;分离物经10项生化指标试验,有99.24％的菌株在醋酸铅琼脂上有轻度的H _2S产生,其余9项反应均符合典型大肠杆菌的特征;经电镜观察,发现O_1、O_(50)、O_(78)、O_(84)、O_(88)、O_(90)和O_(92)等7种血清型有菌毛,在培养72小时后,菌毛的数量及长度均比培养24小时者有所增加;主要血清型分别对鸡进行皮下和气管内两种途径的致病性试验,结果有10种是致病性的,而且还证实菌毛与呼吸道感染的致病性有直接的关系。     

鸡传染性鼻炎自家油乳苗免疫的研究

本试验用从广西分离的二株引起鸡传染性鼻炎的副鸡嗜血杆菌 ( H aemophilus paragallinarum,H.pg) GX 97、GX 981株研制成自家油乳苗 ,进行后备鸡免疫试验 ,免疫后 3、 6、 9和 1 2个月进行免疫抗体检测和攻毒试验。结果表明 ,免疫后 6个月 90 %免疫鸡的抗体滴度在 1∶ 640以上 ,9个月抽样攻毒有 75%～ 80 %的鸡获得保护。大田免疫试验也获得了良好的效果。证明自家油乳苗免疫接种也是防制该病的一个有效途径。     

鸡大肠杆菌质粒指纹图谱及某些生物学特性的研究

用广西分离的鸡大肠杆菌(E.coli)11种血清型的代表菌株进行研究。结果表明:鸡E.coli的致病性与血清型、菌毛及大肠杆菌素(colicin)的产生有关;与细菌的抗药性关系不大;鸡E.coli不产不耐热肠毒素(LT)及耐热肠毒素(ST);鸡E.coli的血凝特性及盐凝特性与其菌毛的产生有关;来源及血清型相同的菌株才具有完全相同或基本相同的质粒指纹图谱(PP)和酶切图谱;质粒分布与血清型及菌毛的产生无明显关系,与colicin的产生及抗约性有较密切的关系。结果还表明,鸡E.coil与其它人畜致病性E.coli有显著的区别。并对此作了进一步的讨论。     

禽多杀性巴氏杆菌和大肠杆菌二联灭活油乳剂疫苗免疫保护试验

用禽多杀性巴氏杆菌和大肠杆菌本地分离菌株,分别液体培养、灭活,按一定比例混合,加入油佐剂制成二联灭活油乳剂疫苗。以0．5mL／只、1．0mL／只两个剂量分别肌肉注射免疫2月龄非免鸡30只,同条件设非免疫对照组8只,免疫后21d用两种分离菌株分别攻毒及两种菌混合攻毒。试验结果显示,对禽多杀性巴氏杆菌的保护率为80％,对大肠杆菌病的保护率为100％,对两种菌混合攻毒的保护率为80％。本试验结果说明研制的二联灭活油乳剂疫苗安全有效。     

钴—60γ射线诱变的多杀性巴氏杆菌Str.R株及其毒力免疫原性的研究

以同位素钴—60γ射线处理,得到一株禽源的多杀性巴氏杆菌(Pasteurella multocida)链霉素耐药性(Str·R)突变株,暂称为GNCo 1株。 GNCo 1株以能在高浓度(500μg/m1)链霉素环境中生长和较亲代株生长慢为特征。毒力减弱,星布洛鸡以活菌102.9亿、广西三黄鸡以活菌60亿皮下注射不发病,家兔耐受30亿活菌皮下注射(更高未测);对小白鼠比亲代菌株PD_1毒力减弱10~(3-4)倍。与同时试验的“1010”株、“广农系”弱毒株毒力相近,比“731”株弱。通过有链霉素或无链霉素的人工培养基各30代,小白鼠18代,鸡3代(更多代未试),链霉素耐药性和毒力稳定,亦未发现链霉素依赖性突变。耐药性转移试验阴性。免疫不同品种、日龄的鸡13组,100％保护的5组(38.46％);80％保护1组(7.7％);60—67％保护4组(30.77％);50％保护2组(15.38％);20％保护1组(7.7％)。保护率50％以上的有12组,占13个试验组的92.3％。其中饮水免疫1组,保护4/6(67％)。两个月以后攻毒的组,亦保护80％以上。小群野外免疫不同品种的鸡1429只,无严重反应。GNCo1株在鸡体内主要停留于注射局部,存活期8—14天。     

免疫抑制素提高粤黄鸡产蛋性能的研究

将鸡抑制素α亚基成熟肽cDNA片段克隆入表达载体pRSETA的BamHⅠ和HindⅢ位点之间,在大肠杆菌(Es-cherichiacoli)BL21(DE3)中表达了分子量为15.8kD左右的重组鸡抑制素融合蛋白,在0.005mmol/LIPTG诱导4h时达最高表达量,约占总菌体蛋白的37%。将此融合蛋白用Ni-NTA树脂经亲和层析纯化后与矿物油佐剂制成蛋白含量为1mg/mL的免疫原。对25只240日龄的粤黄鸡种(Gallusgallus)母鸡在第5和第26天肌肉注射1mL重组鸡抑制素融合蛋白免疫原,另外25只种鸡接种1mL不含蛋白的油乳剂。免疫组鸡在首次免疫后血浆抗重组鸡抑制素的抗体水平持续且极显著高于对照组(P<0.01)。在50d试验期内,免疫组鸡的产蛋量在第2次免疫后明显高于对照组约5%￣8%左右,表明鸡免疫抑制素重组融合蛋白仅能有限地提高其产蛋性能。     

牛脾转移因子对雏鸡免疫功能的影响研究

为探究转移因子(TF)对雏鸡免疫功能的影响,本研究将120只1日龄健康科宝-500雄性雏鸡随机分为6组(对照、TFⅠ、TFⅡ、TFⅢ、TFⅣ、TFⅤ组),每组5个重复,每个重复4只雏鸡。在7日龄时,对照组和TF组雏鸡均接种新城疫疫苗,TF组另注射不同体积的2 mg·m L-1TF提取液,试验周期为22 d。结果表明,TF组雏鸡采食量、体增重和料肉比均优于对照组;TFⅤ组胸腺和法氏囊脏器指数均显著升高(P0.05)。组织学检查显示,TF组雏鸡中枢免疫器官内淋巴细胞较对照组排列紧密,且脾脏各组间未见差异性;TF可显著或极显著升高雏鸡外周血T淋巴细胞亚群百分比和新城疫抗体滴度,同时增强巨噬细胞吞噬功能。7日龄时,注射0.4~0.6 mg·只-1剂量的TF可不同程度地提高雏鸡的生长性能,促进免疫器官生长发育,增强免疫功能。本研究为TF在兽医临床及动物养殖方面的应用提供了一定的参考和理论依据。     

法氏囊素在大肠杆菌中的表达及其免疫增强活性

选用大肠杆菌(Escherichiacoli)编码赖氨酸(Lys)、组氨酸(His)和甘氨酸(Gly)的常用密码子按顺序排列成BS基因:5'-AAACACGGT-3'。连续合成10个BS(BS10)串连基因单链及其反向互补链,通过退火使其复性成双链。BS10基因经EcoRⅠ和SalⅠ双酶切后,克隆进表达载体pGEX-6P-1中。获得的重组质粒pGEX-Bur转化大肠杆菌BL21,经IPTG诱导,串连的BS10基因获得了高效表达。表达产物经GST亲和层析和胰酶消化处理后,按适当的浓度和新城疫病毒(NDV)混合,免疫90只30日龄的小白鼠。分别在免疫后第7,14和21天,用血凝抑制试验(HI)测定小鼠血清中NDV的抗体水平,结果加入囊素的实验组比不加囊素的对照组HI平均高出22.5个滴度。同样的实验样品免疫100只8日龄SPF(speclficpathogenfree)鸡,15d后实验组的抗体水平比对照组平均高出20.7个滴度。研究结果证实了用大肠杆菌表达的法氏囊素对小鼠和鸡具有免疫增强的作用。     

广西霞烟鸡抗马立克氏病选育报告

鸡的马立克氏病(MD)抗病育种是防制 MD 的一个新方向。经三年多的研究,采用马立克氏病病毒(MDV)强毒株攻击霞烟鸡1日龄雏鸡,选留幸存者进行繁殖,其后代未经MD 疫苗接种,以自然感染进行选择,并结合后裔攻毒测定法进行抗 MD 的选育。至三世代时,鸡抗 MD 的能力已大为提高。三世代雏鸡1日龄攻毒后,10周龄时 MD 总保护率为74%,与对照组的35%有非常显著的差异(P<0.001),其中自然死亡鸡的 MD 肿瘤阳性率为16%,与零世代的48.1%有非常显著的差异(P<0.001).与对照组的37.5%亦有显著差异(P<0.05);1日龄经火鸡疱疹病毒(HVT)疫苗免疫,14日龄以 MDV 强毒攻毒后,三世代10周龄时对 MD总保护率为96.9%,而对照组为87%。抗病核心群目前已有基本种鸡500羽。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.