利用PCR法鉴定产SLT—Ⅱe大肠杆菌

民贺氏菌毒素Ⅱ型变异性，是仔猪水肿病的主要致病历子。根据ＳＬＴ－Ⅱｅ基因序列，合成一对针对ＳＬＴ－Ⅱｅ操纵子基因保守区的寡核苷酸引物，建立了聚合酶链反应扩增方法。通过对产ＳＬＴ－Ⅱｅ毒素大肠杆菌菌株ＴＢ１，产ＳＬＴ－Ⅱ毒素大肠杆菌菌株９３３Ｗ和产ＳＬＴ－Ⅰ毒素大肠杆菌菌株Ｈ３０的试验，结果表明用所设计的引物建立的ＰＣＲ方法可特异性鉴定产ＳＬＴ－Ⅱｅ大肠杆菌。     

行业简报

新型添加剂防鸡细菌性腹泻 抗分泌因子，一种饲料添加剂──饲料诱导卵磷脂添加于饲料或饮水，能有效地预防鸡的细菌性腹泻。 抗分泌因子（ＡＳＦ）由鸡中枢神经系统产生，主要聚集在鸡的脑垂体腺。抗分泌因子通常经血液和胆汁输送到胃，它作为调节蛋白能阻止细菌向肠道分泌毒素，但是受大肠杆菌毒素的作用，抗分泌因子的分泌大量减少，在饲料中使用添加剂可提高鸡血浆中抗分泌因子的浓度。 一种特殊类型的抗分泌因子，取名为饲料诱导卵磷脂，可作为各种饲料添加剂且十分有效。该抗分泌因子与毒素诱导的抗分泌因子具有相同的抗分泌性质，但…     

利用PCR法鉴定产SLT-IIe大肠杆菌

类志贺氏菌毒素Ⅱ型变异体（ Ｓｈｉｇａｌｉｋｅ Ｔｏｘｉｎ Ⅱ Ｖａｒｉａｎｔ, Ｓ Ｌ ＴⅡｖ ｏｒ Ｓ Ｌ ＴⅡｅ）,是仔猪水肿病的主要致病因子。根据 Ｓ Ｌ ＴⅡｅ 基因序列,合成一对针对 Ｓ Ｌ ＴⅡｅ 操纵子基因保守区的寡核苷酸引物,建立了聚合酶链式反应（ Ｐ Ｃ Ｒ）扩增方法。通过对产 Ｓ Ｌ ＴⅡｅ 毒素大肠杆菌菌株 Ｔ Ｂ１、产 Ｓ Ｌ ＴⅡ毒素大肠杆菌菌株 ９３３ Ｗ 和产 Ｓ Ｌ ＴⅠ毒素大肠杆菌菌株 Ｈ３０ 的试验,结果表明用所设计的引物建立的 Ｐ Ｃ Ｒ方法可特异性鉴定产 Ｓ Ｌ ＴⅡｅ 大肠杆菌。用此法对本实验室从患水肿病仔猪肠道分离的 １５ 株大肠杆菌进行了鉴定,结果可从 １５ 个菌株的 １２ 株中扩增到 Ｓ Ｌ ＴⅡｅ 的特异性保守序列基因片段,而其它菌株未见此保守序列的基因片段。     

嗜水气单胞菌HEC毒素基因的克隆及酶谱分析

嗜水气单胞菌ＨＥＣ毒素是该菌重要的致病因子和保护性抗原。为了解其分子生物学特性，用ＳＤＳ－蛋白酶Ｋ法提取了嗜水气单胞菌Ｊ－１株的染色体，经ＥｃｏＲＩ酶切、琼脂糖凝胶电泳后作Ｓｏｕｔｈｅｒｎｂｌｏｔｔｉｎｇ，用ＤＩＧ标记的ＨＥＣ毒素探针检测，其５．０ｋｂ的酶切片段呈阳性。回收该片段，与ｐＵＣ１９相连，转化大肠杆菌ＪＭ１０９。提取Ｘ－ｇａｌ平板上白色菌落的质粒，经大小比较、ＥｃｏＲＩ酶切分析及ＤＩＧ标记ＨＥＣ毒素核酸探针斑点杂交鉴定，获得ｐＨＥＣ１１等含５．０ｋｂ目的ＤＮＡ片段的重组质粒。ｐＨＥＣ１１质粒经酶切、电泳，证实目的ＤＮＡ片段中含有ＢａｍＨＩ、ＳｍａⅠ、ＰｓｔⅠ及ＰｖｕⅡ等酶切位点，并绘制了其物理图谱。同时还构建了若干亚克隆，为研制嗜水气单胞菌基因工程苗提供了目的基因片段。     

抗破伤风毒素单克隆抗体杂交瘤细胞系的建立及其中和效应

应用破伤风类毒素多途径免疫接种ＢＡＬＢ／ｃ小鼠。取小鼠脾细胞与ＳＰ２／０小鼠骨髓瘤在聚乙二醇（ＰＥＧ，４０００）作用下进行细胞融合，克隆化，经ＥＬＩＳＡ及毒素中和试验检测，获得了１１株具有一定毒素中和活性的单克隆抗体细胞株。经单一单抗和群单抗中和试验证实，其中４株具有较强的产生抗毒素活性，而且这４种单克隆抗体（１Ｄ９Ｂ１０、５Ｇ８Ｂ９Ｅｌ、５Ｇ８Ａ１０、５Ｇ８Ｂ９Ｃ１１）协同作用可完全中和标准量毒素的攻击。     

我来说说奶牛黄曲霉毒素中毒的治疗

黄曲霉毒素中毒是人畜共患并且严重危害的一种真菌毒素中毒性疾病。黄曲霉毒素，目前已发现有20种，其中以B1、B2、G1、G2毒素毒力最强，尤其是B1更突出的强，所以目前的黄曲霉毒素均指B1，由于该毒素可致癌，动物饲喂后其产品如奶对人的健康有影响。黄曲霉毒素在体内吸收后．微量进入血液，肌肉中基本没有，移行于肝、奶中较多。奶牛采食含该毒素的饲料。奶中含有黄曲霉毒素产物黄曲霉毒素M1其毒性与黄曲霉毒素B1近似。由于幼小动物对该毒素最敏感。乳又是大多数婴儿的重要食品，因此，对乳中黄曲霉毒素M1含量问题人们十分观注。     

抗产气荚膜梭菌ε毒素单克隆抗体的研制和部分特性鉴定

小鼠ＳＰ２／０骨髓瘤细胞和用产气荚膜梭菌ε类毒素免疫ＢＡＬＢ／Ｃ鼠的脾细胞，以ＰＥＧ为融合剂进行融合，获得分泌抗产气荚膜梭菌ε毒素单克隆抗体的杂交瘤细胞株１３株，经鉴定，杂交瘤所分泌的单克隆抗体在ＥＬＩＳＡ中均特异地与产气荚膜梭菌ε毒素反应，而不与α和β毒素反应，１３株单克隆抗体均为ＩｇＧ１亚类，经毒素抗毒素中和试验测定，１３株单克隆抗体中，１２株具有中和ε毒素的活性。     

产气荚膜梭菌毒素Dot—ELISA测定方法的研究

建立了一种以硝酸纤维素膜为载体,采用抗ε毒素单克隆抗体,羊抗β毒素ＩｇＧ和羊抗α毒素ＩｇＧ为吸附抗体测定产气膜梭菌毒素的Ｄｏｔ－ＤＬＩＳＡ,８株参考菌株的除菌含毒素培养液和８份加入已知含毒素培养液的肠内容物经Ｄｏｔ－ＥＬＩＳＡ、小白鼠致死试验和小白鼠中和试验测定,结果完全一致,由于该法采用纯化抗体吸附抗原的方式,有效地降低了非特性反应的发生。不仅可以进行培养液中毒素的测定 地检出加和肠内容物中的毒     

牛住肉孢子虫毒素的毒性

牛住肉孢子虫毒素的毒性李世平董明显（中国农业科学院中兽医研究所兰州７３００３０）早在１９世纪末，就有学者从住肉孢子虫囊中分离出毒性物质，遂称为住肉孢子虫毒素（Ｓａｒｃｏｃｙｓｔｉｓｔｏｘｉｎ，Ｓａｒｃｏｃｙｓｔｉｎ）。１９２１年日本人Ｓａｉｔｏ率先从...     

绿脓杆菌外毒素A的纯化

用绿脓杆菌ＰＡ１０３株接种于ＴＳＡ甘油培养基３２℃培养，产生绿脓杆菌外毒素Ａ（ＰＥＡ），经流水透析除盐、ＤＥ－５２纤维素阶段洗脱、硫酸铵分级沉淀、ＳｅｐｈａｄｅｘＧ－２５除盐、ＤＥ－５２纤维素梯度洗脱、ＳｅｐｈａｄｅｘＧ－２００分子筛层析，纯化了绿脓杆菌外毒素Ａ。ＳＤＳ－ＰＡＧＥ分析，纯化后的毒素为单一蛋白带，分子量约６６０００；对普通小鼠ＬＤ５０为０．２４μｇ蛋白。用ＰＥＡ抗血清作免疫印迹分析，进一步证实纯化的蛋白为ＰＥＡ，毒素约纯化了５００倍，总蛋白回收率约０．０２４％，毒素回收率约１１％。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein