产气荚膜梭菌和腐败梭菌在厌氧菌基础培养基中的生长特性

测定了产气荚膜梭菌B型、D型和腐败梭菌在新研制的厌氧菌基础培养基中的生长曲线和产毒能力等特性。结果表明,这些细菌可以在新培养基中良好生长和产毒。产气荚膜梭菌B 型经2 h 的适应期后,很快进入对数生长期,培养到8 h细菌密度接近最高值,OD630为4.329;经检测,培养4 h~24 h的细菌所产生的毒素(培养物上清)1μL~2μL可致死KM小鼠。产气荚膜梭菌D型的生长速度也较快,无适应期就直接进入对数生长期,培养到12 h 时细菌密度最高, OD630 为1.75;细菌最佳产毒期在6 h~14 h,培养物上清0.5μL~0.65μL可致死KM小鼠。腐败梭菌生长速度较慢,经6 h的适应期后,才进入对数生长期,培养到14 h时细菌密度最高,OD630为1.335;细菌毒力在培养后的6 h~24 h内10μL菌液可达到在24 h内致死KM小鼠的效果。     

D型魏氏梭菌毒素研究进展

魏氏梭菌病是由魏氏梭菌引起的一种重要的人兽共患传染病。可导致各种动物的肠毒血症或坏死性肠炎,D型魏氏梭菌病包括牛、羔羊、绵羊、山羊以及灰鼠的肠毒血症等。D型魏氏梭菌所产的毒素是引起动物死亡的重要因素之一,本文综述了D型魏氏梭菌毒素的结构、功能以及检测方法的研究进展。     

D型产气荚膜梭菌最佳产毒时间及毒素大小的确定

本实验测定了D型产气荚膜梭茵在肝片肉汤培养基的生长曲线、培养液的pH值变化曲线以及不同培养时间提取的毒素液的蛋白质含量,并用SDS--PAGE电泳方法检测了所提毒素为α、ε毒索。结果表明,D型产气荚膜梭茵在肝片肉汤培养基培养18h是其α、ε毒素的最佳产毒时间,毒素大小分别是43kD、35kD。     

Isolation and typing of Clostridium oedematiens (Cl. novyi) from cases of black disease of sheep in Iran

Clostridium oedematiens types A, B and D have been isolated from liver lesions of 44 cases of black disease of sheep in Iran. The technique of isolation and identification by using fluorescent labelled antibodies is described. The isolates were typed based on their lecithinase, haemolytic, necrotic and lethal activities.     

Isolation of Clostridium novyi (Cl. oedematiens) from liver lesions in a dog with pancreatic acinar carcinoma

This paper records the isolation of Clostridium novyi from liver lesions in a dog with pancreatic acinar carcinoma and multiple hepatic metastases.     

Studies of necrotizing enteritis of suckling piglets (Cl. perfringens typc C enterotoxemia) in industrialized sow breeding units. 3. Experimental reproduction of the disease]

Experimental reproduction of necrotising enteritis of sucking pigs was successfully achieved by using both Clostridium perfringens Type C strains, which had been isolated from sucking pigs with necrotising enteritis, and Type C strain 3628 of A.T.C.C. (sub-type C1). The lethal dose for sucking pigs was between 20 X 10(6) and 12 X 10(7) pathogens per animal. The disease could not even be induced by repeated application of no-bacterial toxin of Cl. perfringens Type C nor by administration of Cl. perfringens Type A strains which had been cultured from broilers with necrotising enteritis. Necrotising enteritis was found to develop in two phases in sucking pigs. First, the pathogen will deposit to the villous epithelium and then penetrate the superficial strata of the mocous membrane. In the second phase, the villous structure will be destroyed by the lethal, haemolysing, and necrotising toxins of Cl. perfringens. The role played by individual toxin fractions is discussed together with the importance of humoral and localised infection defence. Sucking pigs may be sufficiently protected against infection based on single or ten-fold lethal infectious dosage by two vaccinations of the mother animal, five and three weeks prior to parturition, using "Enterotoxaemia Vaccine Dessau bivalent". Infection then would not occur unless a hundredfold lethal dose was applied. Characteristics include diarrhoea, apathy, exhaustion, and death.     

Pharmacokinetics of ruminally dosed sodium [36Cl]chlorate in beef cattle

The recently recognized potential of sodium chlorate as a possible preharvest food safety tool for pathogen reduction in meat animals has spurred interest in the pharmacokinetics of intraruminally dosed chlorate. Six Loala cattle were assigned (one heifer and one steer per treatment) to one of three intraruminal doses of radiolabeled sodium [36Cl]chlorate (21, 42, or 63 mg/kg body weight) administered in four equal aliquots over a 24-h period. Blood and serum were collected (29 samples in 48 h). Total radioactive residues were measured and the radioactive moieties were speciated. Chlorate appeared rapidly in blood and serum after dosing. For animals administered a dose of 42 or 63 mg/kg, the half-life of absorption was estimated at 0.6-0.9 h. Serum chlorate concentrations progressively increased with aliquot administration until peaking at 6-21 parts per million at 26 h. Between aliquot administrations, serum chlorate levels typically peaked in 3.5 h or less. The half-life of chlorate elimination ranged between 6.9 and 11 h, depending on the dose. Ultimately, absorption of chlorate removes it from its desired site of action, the lower gastrointestinal tract, thereby reducing its efficacy. Further research is needed to develop a chlorate formulation that will allow passage to the lower gastrointestinal tract.     

NH_4Cl和NaHCO_3对肉用仔鸡慢性热应激的影响

３２０ 羽１ 周龄健康肉用雏鸡被随机分成４ 组, 经１ 周的适应后进行试验。组Ⅰ、组Ⅱ、组Ⅲ和组Ⅳ的日粮处理分别为： 基础日粮（Ｂ, 对照组） , Ｂ＋ ０－５ ％ ＮａＨＣＯ３ , Ｂ＋ ０－５ ％ ＮａＨＣＯ３ ＋ １ ％ ＮＨ４Ｃｌ 和Ｂ＋ １ ％ ＮＨ４Ｃｌ。试验为期５ 周。研究日粮中添加ＮａＨＣＯ３ 和ＮＨ４Ｃｌ 对慢性热应激肉用仔鸡的血液ｐＨ、ＣＯ２ 分压（ＰＣＯ２） 及生产性能的影响。结果表明： 在慢性热应激（２３ ～３５ ℃） 条件下, 肉用仔鸡未发生呼吸性碱中毒, 组Ⅱ的血液ＰＣＯ２高于对照组（ Ｐ＜ ０－０１） , 增重比对照组多９－４９ ％ ; 组Ⅲ血液ｐＨ 低于组Ⅰ和组Ⅱ（ Ｐ ＜ ０－０１） , 血液的ＰＣＯ２ 高于组Ⅰ和组Ⅳ（ Ｐ ＜ ０－０１） , 增重比对照组多８－１９％ 。组Ⅳ的血液ｐＨ 值极显著低于对照组（ Ｐ ＜ ０－０１） , 比对照组少增重２－５ ％     

The influence of selected tannin-containing plant species on the tenacity of pathogenic bacteria in an in-vitro rumen system. 1. Communication: the influence of selected plant species on the tenacity of Cl. perfringens

The effect of plant species containing tannins on the tenacity of Cl. perfringens was elucidated. Trials were purchased in physiological saline solution and in a rumen-fluid-medium under anaerobic conditions. The results obtained show, that within minutes the tenacity of Cl. perfringens can be reduced by some of the tested plant material not only in physiological saline solution but also in a rumen-fluid-medium. The results indicate that the reaction of some vegetable tannins and Clostridium perfringens germs is a specific one and could be used in controlling diseases caused by Clostridium perfringens.