Biofilm production by pathogens associated with canine otitis externa,and the antibiofilm activity of ionophores and antimicrobial adjuvants

Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N‐acetylcysteine (NAC), Tris‐EDTA and disodium EDTA) were investigated spectrophotometrically (OD_570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000–10,000 µg/ml and from 20,000–80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris‐EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16‐fold and eightfold higher than the MIC/MBC of NAC and Tris‐EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris‐EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm‐associated OE in dogs.     

Isolation and identification of a South China strain of Plasmodium inui from Macaca fascicularis

Southeast Asian macaques are hosts of a number of Plasmodium infections, some of which are transmittable to humans. During examination of blood films of five wild-caught long-tailed macaques Macaca fascicularis from South China, malaria infection was detected in one of the monkeys. In order to isolate this parasite for identification and characterization, we experimentally passed this parasite through both Assamese (M. assamensis) and rhesus (M. mulatta) monkeys by intravenous injection of infected blood. This parasite morphologically resembled Plasmodium inui, and had a typical 72 h quartan periodicity. This parasite was infective to Anopheles dirus mosquitoes, and salivary gland sporozoites appeared 13 days post feeding. Feeding by 20 infected An. dirus mosquitoes on another Assamese monkey produced infection with a prepatent period of 8 days. Molecular analysis of the small subunit rRNA genes and the mitochondrial genome confirmed this parasite as an isolate of P. inui. In spleen-intact macaques, the infection had a protracted duration with parasites being detected during the rearing of the infected monkeys for over two years. In summary, this study identified a P. inui isolate and successfully passed this parasite through Assamese monkeys by both intravenous inoculation and mosquito transmission.     

猪某些免疫指标及其与部分生产性状关系的研究

实验测定了哈白、杜洛克猪３月龄和５月龄的总数Ｅ－玫瑰花环形成细胞百分率、活性Ｅ－玫瑰花环形成细胞百分率、淋巴细胞转化率、血清ＩｇＧ含量及５月龄接种布氏杆菌猪型二号苗后７、２１、３５６的特异性抗体滴度，对这些免疫指标及其与部分生产性状的关系进行了分析，旨在为猪的抗病育种提供依据。实验结果表明：（１）３月龄和５月龄几个免疫指标均存在品种差异，哈白猪显著地高干杜洛克猪；（２）３月龄与５月龄间所测细胞免疫指标无显著差异，但５月龄血清ＩｇＧ含量显著高于３月龄血清ＩｇＧ含量；（３）哈白与杜洛克猪对布氏杆菌疫苗的抗体应答能力存在显著差异；（４）所测定的细胞免疫指标间大多表现正的相关，体液免疫指标间亦表现正的相关，而细胞免疫指标和体液免疫指标间大多具有较弱的相关；（５）所测定的几个免疫指标与生产性状间大多具有较弱的相关。     

pH值对星突江鲽消化酶活性的影响

实验通过改变酶反应中的pH值,分析了星突江鲽蛋白酶、淀粉酶和脂肪酶的活性。结果表明,胃、肠和肝胰腺蛋白酶活性的最适pH值分别为3.8、8.2和7.8,各消化部位的最高点蛋白酶活性从高到低为:胃>肝胰腺>肠。胃、肠和肝胰腺淀粉酶活性的最适pH值分别为6.6、7.4和7.0,各消化部位的最高点淀粉酶活性从高到低为:肠>肝胰腺>胃。胃、肠和肝胰腺脂肪酶活性的最适pH值分别为7.4、7.8和7.8。各消化部位的最高点脂肪酶活性从高到低为:肝胰腺>肠>胃。     

益生元及其应用研究进展

目前,对肠道菌群的调整手段主要有2种：活菌补菌（即益生菌补菌）和自身肠道菌增殖（即益生元补菌）。主要叙述了益生元的概念、种类、生理机能及应用现状和趋势。     

国内外肉牛分子标记辅助育种的研究进展

分子标记辅助育种(Marker assisted selection,MAS),直接从DNA分子水平上反映种间差异,不受环境、发育阶段、组织等的影响,稳定可靠,多态性好,因而在家畜育种中被广泛利用,本文详尽概述了分子标记辅助选择对于遗传力低的性状如肉质性状和屠宰性状等改良效率相关的研究进展。     

斯氏艾美耳球虫ITS1-5.8S rRNA-ITS2序列的克隆及PCR检测方法的建立

通过对多种鸡球虫和松鼠球虫18SrRNA和28SrRNA进行序列比对分析,在18SrRNA 3′端和28SrRNA 5′端保守区设计艾美耳属通用引物,以斯氏艾美耳球虫洛阳分离株LY卵囊基因组DNA为模板首次成功克隆到斯氏艾美耳球虫完整的ITS1-5.8SrRNA-ITS2序列,其大小为1 178bp,其中ITS1序列长度为423bp,5.8SrRNA为155bp,ITS2为600bp,斯氏艾美耳球虫LY株ITS1/2序列高度变异,与鸡球虫、啮齿动物球虫的序列相似性低于60%。然后在斯氏艾美耳球虫ITS1/2序列超变区设计种特异引物,建立了灵敏、特异的PCR检测方法。本研究结果将为兔球虫强致病种的临床诊断和揭示兔球虫种群遗传特征提供有效的分子工具。     

基于电子商务的网络财务管理探悉

电子商务的蓬勃发展给企业管理带来巨大冲击，财务管理作为企业管理链条上的重要一环，其管理模式也因此而发生了重大变革。文中首先介绍了网络财务管理产生的背景及其概念，讨论了网络财务管理的优势所在，明确了网络财务管理产生和发展的技术基础，重点对网络财务管理的开发与实施展开了探讨。