鸡大肠埃希氏菌地方菌株的致病性与药敏试验

分别从死亡鸡胚、病死鸡中分离大肠埃希氏菌 ,进行致病性与药敏试验 ,并鉴定致病性较强的菌株的血清型。结果表明 ,所分离的菌株绝大多数对一日龄鸡有致病性 ,所有血清型对头孢唑啉高度敏感。

云南省结核分枝杆菌地方菌株耐药监测

目的 了解云南省结核分枝杆菌地方菌株耐药情况。方法 采用比例法对所分离的142株菌株进行异烟肼（INH）、利福平（RFP）、链霉素（SM）及乙胺丁醇（EMB）4种的耐药检测。结果 结核分枝杆菌对四种药物的耐药率在10．57％～19．02％之间，初始耐药率为4．06％～13．52％，INH的初始耐药率最高；获得性耐药为21．87％～34．38％，INH、RFP的获得性耐药率最高。结论 云南省结核分枝杆菌地方菌株对4种抗结核药物的耐药率由高到低分别为INH、SM、RFP和EMB，其中INH、SM和RFP3种药物的耐药率与全国基本一致（P〉0．05），而EMB的耐药性远高于全国水平。

大肠杆菌地方菌株的分离与耐药性监测

对共和县某猪场腹泻仔猪和妊娠母猪进行了大肠杆菌的分离和鉴定,分离出15株猪大肠杆菌,其中3株为致病性大肠杆菌。与此进行的耐药性监测结果表明:分离的菌株对氨苄青霉索、青霉素有明显的耐药性,而对丁胺卡那霉索、妥布霉索、头孢哌酮较敏感。

地方土猪源副猪嗜血杆菌16SrRNA基因的分子鉴定及遗传进化分析

为研究地方土猪源副猪嗜血杆菌（Haemophilusparasuis，Hps）的分子遗传进化特性，应用PCR方法扩增河南地方分离株XY0501的16SrRNA基因，并进行遗传进化分析。结果显示，地方土猪源Hps的16SrRNA基因全长为822bp，与国内外参考菌株的核苷酸序列同源性为97．1％～99．3％；与血清5型参考菌株的核苷酸序列同源性高达99．3％；基于16SrRNA基因序列绘制的系统进化树显示，地方土猪源Hps与血清5型Hps参考株属于同一分支。研究结果证明，Hps可感染地方土猪并导致发病，感染来源有待进一步查明；16SrRNA基因在Hps的不同血清型中高度保守，且无品种差异。

猪大肠埃希氏菌地方菌株灭活苗的研制

用本地猪场分离的埃希氏菌08菌株研制氢氧化铝胶灭活苗获得成功，将此菌苗免疫小白鼠(0．2ml／只皮下注射)，免疫后间隔14d攻毒(0．2ml／X腹腔注射)，免疫小白鼠可获得11／12保护，保护率91．7％，对照组5／6死亡。

牛摩拉氏菌中国地方株限制性核酸内切酶的提取与纯化

目的 :为探讨牛摩拉氏菌中国地方株MABL80 11限制酶的存在。方法 :采用改进的GelinasRE等方法对MABL80 11菌株的培养物分别进行超声裂解、离心、盐析、BioGel A0 .5M和磷酸纤维素P11柱层析 ,获得可切割λDNA和pBR332DNA与国际标准酶MboI切点一致的酶提取物。结果 :在改进的条件下 ,30 0 0ml培养物 ,可获得 72 0 0UMboI,纯化率为 2 3.2 % ,酶产出量高于文献报导值。结论 :表明牛摩拉氏菌中国地方株MABL80 11确含MboI限制性内切酶 。

随机扩增多态性DNA技术在沙门氏菌同源性分析中的应用

目的:利用随机扩增多态性DNA技术(random amplified polymorphicDNA,RAPD)对从食品、蛋品样本或从业人员中收集到的67个地方菌株、4个模式菌株,涉及29种血清型的沙门氏菌进行同源性分析,为沙门氏菌食源性疾病的流行病学溯源和疫情控制提供理论依据。方法:选用筛选得到的10个碱基引物(CCGAAGCTGC)运用RAPD技术对不同来源的71株沙门氏菌进行随即引物扩增,得到的RAPD图谱使用NTSYS-pc2.10e软件进行聚类分析。结果:相似性系数在0.70时,71株沙门氏菌可以分为七大类群,其中最多的一群内聚集的菌株达54株,相似性系数在0.90时,可以分为26个群,最多的一群内聚集的菌株达18株,相似性系数为1.00时,有9个组群,最多的一组群内聚集的菌株达11。同源性结果和血清学鉴定的结果有90%的吻合率。结论:RAPD检测技术可以用于沙门氏菌食源性疾病的流行病学调查和溯源。

沙门氏菌属随机扩增多态性DNA PCR条件的优化

目的:以5′-CCGAAGCTGC-3′为引物,利用随机引物扩增多态性DNA技术(random amplified polymorphic DNA,RAPD)对沙门氏菌属的几种菌株进行扩增,以确定RAPD的最终优化条件。方法:首先选用25μl体系PCR和50μl体系PCR做对比,以确定进行RAPD实验最佳的PCR体系。其次进行PCR反应体系条件的优化,对PCR复性温度、引物浓度、Mg2+浓度进行条件优化。最后对初步确定的优化结果进行不同琼脂糖胶浓度梯度的优化以确定RAPD的最终优化条件。结果:RAPD优化条件为PCR复性32℃,25mmol/LMg2+溶液体积2.0μl,10μmol/L引物体积0.2μl,琼脂糖胶浓度1.0%。结论:在优化条件下,以引物5′-CCGAAGCTGC-3′对沙门氏菌属的3种标准菌株,9株食品分离株进行扩增,得到的电泳条带最多,且最清晰。

食品中沙门菌细胞脂肪酸组分的气相色谱分析

目的:建立沙门菌属全细胞脂肪酸气相色谱指纹图谱,为沙门菌的鉴定提供依据。方法:对从食品中分离的6种沙门菌在相同的条件下培养,离心收集细胞,提取脂肪酸并甲基化,通过TLC来分离纯化甲基酯,通过气相色谱测定脂肪酸的组成。结果:沙门菌属中的细菌在脂肪酸的组成上主要含C12、C16、C18、C19,不同种的脂肪酸组分表现出一定的差异,地方菌株与模式菌株具有相同的脂肪酸组分。结论:该方法灵敏度高、重现性好,准确性强可以对食品中的沙门菌进行快速鉴定。

革兰氏阴性致病菌细胞脂肪酸组分的气相色谱分析

通过气相色谱对15株革兰氏阴性致病菌的细胞脂肪酸组分进行分析,可以清晰地分出不同的属其脂肪酸组分有明显地差异,同一属中不同的种也表现出一定的差异,地方菌株与模式菌株具有相同的脂肪酸组分,可以根据脂肪酸组分对食品中致病菌进行快速鉴定。

志贺氏菌RAPD鉴定方法的建立

[目的]为志贺氏菌食源性疾病的流行病学溯源和疫情控制提供理论依据。[方法]利用5个随机引物对4种不同来源的志贺氏菌进行RAPD扩增,并对得到的扩增图谱进行聚类分析。[结果]5个随机引物中,引物S3、S5表现出较好的多态性。在引物S5的扩增图谱中,志贺氏菌属中各菌均有1条600 bp左右和1条1 000 bp左右的共同谱带,而利用该引物扩增其他属细菌,扩增谱带很少或没有。这说明引物S5对志贺氏菌属细菌是特异性的。根据引物5的聚类分析结果,可将8株志贺氏菌分成4个类群。除宋内氏志贺氏菌外,其他3种6株菌间的相似系数均为1.00,与传统的血清型分型结果完全一致。[结论]采用引物S5的RAPD反应可用于志贺氏菌的快速检测。

不同猪源副猪嗜血杆菌河南分离株16S rRNA基因的遗传进化分析

为研究来自河南省不同猪源的副猪嗜血杆菌（Hps）的遗传演化关系,应用PCR方法扩增所分离的良种猪源、家养野猪源和地方土猪源等3株Hps（KF0901、JZ0801和XY0501）的16S r RNA基因,并进行序列比较分析。结果 3株Hps的16S r RNA基因全长均为822 bp,彼此间核苷酸序列同源性为99.3%~99.6%,与参考菌株的核苷酸序列同源性为97.1%~99.4%;基于16S r RNA基因序列绘制的系统进化树显示,本研究中家养野猪源Hps和地方土猪源Hps均属于血清5型,而良种猪源血清5型Hps却与血清12型和血清14型的亲缘关系更近。表明Hps在良种猪、家养野猪和地方土猪之间彼此交叉感染或具有共同来源;并非所有血清5型Hps分离株都属同一分支。

Preparation of Dried Culture of Probiotic Rhizopus oryzae in Two Different Mediums as Feed Additive to Indigenous Chicken

Fungus Rhizopus oryzae has a probiotic potential, but the potency is not yet explored. Probiotics are usually used as feed additive, including to the chicken. Probiotic needs a suitable medium for their life. The aim of the study was to know which preparations can produce suitable medium for the growth of Rhizopus oryzae on the dried culture formed. The study used two preparations. Preparation 1 （a） consisted of rice bran （1 kg） and culture ofRhizopus oryzae on Potato Dextrose Broth （PDB medium） （500 mL）; then preparation 1 （b） consisted of corn grain （1 kg） and culture of Rhizopus oryzae on PDB medium （500 mL）. Preparation 2 （a） consisted of rice bran （1 kg）, culture of Rhizopus oryzae on Potato Dextrose Agar （PDA medium） （seven petri dishes） and was added with sterile distilled water （500 mL）; preparation 2 （b） consisted of corn grain （1 kg）, culture of Rhizopus oryzae on PDA medium （seven petri dishes） and was added with sterile distilled water （500 mL）. The culture of Rhizopus oryzae even both on PDB and PDA were 3 d of incubation. All preparations were incubated for 7 d then they were dried under the sun. Parameter evaluation was the growth performance of the fungus in the dried culture media. The growth performance was analyzed by microscopic analysis and the number of colony of the fungi in the two dried culture media. The results showed that from the macroscopic analysis, the sample of both dried culture media which were placed on PDA medium showed the growth of mycelia and spores of the same kind of fungus and it was proved by microscopic observation that the fruiting bodies （mycelia and spores） of that ftmgus was Rhizopus oryzae. The colonies number of the fungi from preparation 1 （a） and 1 （b） were 0,4 × 10 cfu/gr and 2.4 × 10^3 cfu/gr, respectively, and from preparation 2 （a） and 2 （b） were 1.3 × 10^5 cfu/gr and 8.3 ×10^2 cfu/gr, respectively. It could be concluded that the product of the dried culture of probiotic Rizopus oryzae from the preparation 2 with rice brand or corn grain mediums can be used as feed additive to indigenous chicken.

Phytophthora Root and Crown Rot on Fruit Trees in Bulgaria

Phytophthora root and crown rot was found on the fruit trees in Bulgaria for the first time in the period 1998-1999. Monitoring of the disease spread from 2000 to 2007 points out incidence between 2 and 14 per cent, in some orchards and nurseries in the Southern part of Bulgaria. The following Phytophthora species were identified based on morphological and cultural characteristics, and temperature requirements： Phytophthora cactorum, Phytophthora citrophthora, Phytophthora drechsleri, Phytophthora cryptogea, Phytophthora hybrid specie and Pythium. Prevailing specie was P. cactorum. P. cryptogea and P. cactorum were confirmed by application of molecular methods. Nutritional requirements of P. cactorum and P. citrophthora were studied. Most Nitrogen sources stimulated the mycelial growth of P. cactorum to a higher extend, and reduced the colony size ofP. citrophthora. Different Carbon sources were utilized well by P. cactorum, and only saccharose and maltose had a stimulating effect on the mycelial growth of P. citrophthora. MgSO4.7H20 was the preferred sulfur source for both fungi, as L-cysteine and L-methionine only for P. cactorum. Phytophthora infection leads to physiological changes in the.host plant tissues. The tendency traced out is： about disorders in the amino acid metabolism, increase in the total sugars and slight reduction of the cellulose content. The total nitrogen, phosphorus and potassium content are reduced and the calcium and magnesium are increased. Photosynthesis of inoculated plants was suppressed and transpiration was increased.

Efficiency of Biological Nitrogen Fixation of Bradyrhizobium under Different Soil Fertility Levels as Measured by 15N Dilution Analysis

The objective of this study was to determine the efficiency of biological nitrogen fixation （BNF） of local Bradyrhizobium isolates in soil of various fertility levels using 15N dilution technique. Local isolates were obtained from cowpea rhizosphere in fields of different Iraqi provinces. Six isolates were selected in this study, which was conducted as a pot experiment under greenhouse conditions. Effects of the following fertility levels were evaluated： at F1, 0 mg N, P and K was added; at F2, 25 mg N/kg soil, 10 mg P/kg soil and 25 mg K/kg soil were added, respectively; the other two levels were F3 at which 50, 20 and 50 mg/kg soil and at F4 75, 30 and 75 mg/kg soil for N, P and K, respectively, were added. Urea, labeled with 15N 10% access atom （aa）, was used as a source of N. The highest BNF was observed under the lowest fertility level, i.e., F1. BNF across all isolates was markedly decreased with the increase of nutrient application to soil, being totally eliminated at the highest fertility level F4. Numbers of nodules per plant root of all isolates were the least under the zero nutrients application and the highest nodules number were found under the highest levels of N, P and K application. Number of nodules does not necessarily reflect the best BNF efficiency of all isolates. However, fertility levels were of significant effect on average nodule number of all isolates. The lowest plant dry weight was under the first fertility level F1 irrelevant of Rhizobium isolates. In general, the highest plant dry weight was under the second soil fertility level F2.

Water Repellency in Calcareous Soils Under Different Land Uses in Western Iran

Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on soil water repellency in calcareous soils of western lran. In this study, soil water repellency and its affecting factors were studied using 20 soil series collected from Hamadan Province~ western Iran. The effects of soil properties including organic carbon content （SOC）, total nitrogen （TN）, C：N ratio, texture, CaCO3 content, and both fungal and bacterial activities on water repellency were investigated using air-dried, oven-dried and heated soil samples. Water repellency index （WRI） was determined using the short-time sorptivity （water/ethanol） method. To distinguish the actual effects of SOC, a set of soil samples were heated at 300 ~C to remove SOC and then WRI was measured on the heated samples. Relative water repellency index （RWRI） was defined as the change of WRI due to heating relative to the oven-dry WRI value. Results of the WRI values showed that the soils were sub-critically water-repellent. Pasture soils had higher WRI values compared to tilled soils, resulting from high SOC and TN, and high activities of bacteria and fungi. It was observed that SOC, TN, fungal activity, and SOC：clay ratio had significant positive impacts on WRI. Strong positive correlations of RWRI with SOC, TN and fungal activity were also observed. Pedotransfer functions derived for predicting WRI showed that the WRI values had an increasing trend with the increases in fungal activity, salinity, alkalinity and fine clay content, but showed a decreasing trend with increasing bacterial activity.