肠道病毒衣壳蛋白致病性研究进展

肠道病毒是人类感染率很高的一种病毒,其衣壳蛋白在病毒的致病性方面起着重要的作用.近年来,大量的研究工作致力于肠道病毒农壳蛋白的致病性研究.此文就衣壳蛋白的基因组结构、基因分型、与病毒受体的相互作用和疫苗研制等方面作了综述.     

经皮肤损伤感染马尔尼菲青霉菌致病力动物实验研究

目的研究马尔尼菲青霉菌经皮肤损伤途径感染小鼠致病力情况。方法将马尔尼菲青霉菌野生株和人感染株孢子悬液分别注入鼠尾皮内,观察接种后发病情况,于第15,50 d分批处死、解剖。结果马尔尼菲青霉菌导致小鼠皮肤感染发病率为100%,而85%小鼠皮损可自行消退痊愈,15%小鼠出现皮肤播散性感染;组织病理示:皮损处细胞性炎症反应在皮损中显著。从发病时间和早期病变严重程度比较,野生株致病力显著强于人感染株(P<0.05);但是从后期病变严重程度和自行痊愈率比较,野生株和人感染株致病力差异无显著性(P>0.05)。结论马尔尼菲青霉菌可以经皮肤损伤引起小鼠致病,其引起机体剧烈细胞免疫应答反应是致病力重要因素之一;野生株和人感染株感染早期致病力有差异,预后无差异。     

5种食源性致病微生物毒力基因重组质粒的构建、克隆表达与表达产物的研究

目的构建大肠杆菌O157∶H7、副溶血性弧菌、金黄色葡萄球菌、沙门氏菌和志贺氏菌5种主要食源性致病微生物毒力基因重组质粒载体并鉴定其表达产物,为探讨高通量磁性荧光纳米颗粒标记相应的抗体技术快速检测带毒力基因的致病微生物的可行性奠定基础。方法分别从5种食源性致病微生物毒力岛中选择特异性的毒力基因进行引物设计,分别提取5种目的细菌DNA片段,经PCR扩增、电泳回收目的基因片段,将目的基因片段与原核表达载体pET-23a、pET-28a、pET-32a构建各自的重组质粒,将重组质粒转化入大肠杆菌DH5α内并提取质粒载体,构建后的重组质粒进行酶切和测序鉴定,再转化入表达宿主E·coliBL21（DE3）。在0.1 mmol/L的IPTG诱导下,目的质粒载体在E·coliBL21（DE3）株中表达,SDS-PAGE电泳检测表达蛋白。结果实验成功构建大肠杆菌O157∶H7、副溶血性弧菌、金黄色葡萄球菌、沙门氏菌和志贺氏菌等细菌的毒力基因重组质粒载体pET-23a-eaeA、pET-28a-tdh、pET-28a-enterotoxin B、pET-32a-invA和pET-28a-ipaH,并克隆出969 bp的eaeA基因片段、567 bp的tdh基因片段、798 bp的enterotoxin B基因片段、1 041 bp的invA基因片段和771 bp的ipaH基因片段。重组质粒载体经酶切和测序与目标基因序列一致。在E·coliBL21（DE3）株中有质粒表达蛋白37.5 kDa（eaeA）、26 kDa（tdh）、34.5 kDa（enterotoxin B）、41 kDa（invA）、32 kDa（ipaH）。结论本研究成功构建了5种食源性致病微生物毒力基因重组质粒并在原核细胞中高效表达,为下一步获得相应的毒力基因抗体及快速诊断试剂的研制应用奠定了基础。     

Potential roles of laccases on virulence of Heterobasidion annosum s.s.

Laccases, multi-copper-containing proteins, can catalyze the oxidation of phenolic substrates and have diverse functions such as a virulence factor in fungi. However, limited information can be found on the role of laccases in the interaction of Heterobasidion annosum s.s. to its host plant. Due to genome availability of the close-related species Heterobasidion irregulare, which contains 18 predicted laccase-encoding genes, phylogenetic analysis and gene expression profiling were performed. Eighteen laccase genes could be classified into 4 groups based on protein domains and phylogenetic analysis. However, there is no clear indication between phylogeny and domain compositions in laccases, and lifestyles of fungal species. The results of qRT-PCR showed that the expression of 8 laccase genes was highly up-regulated in Scots pine seedlings at 1 wpi. These data suggested that they might be involved in early stage of host infection. In addition, up-regulation of gene expression under glucose condition as a sole carbon source suggests that those laccases are not under carbon catabolite repression. Higher activities of laccase were observed in culture media containing cellulose, sucrose, or glucose compared to that of cellobiose as a sole carbon source. The highest mortality of Scots pine seedlings was observed when infected by H. annosum s.s. on extra carbon source as glucose. This was supported by the facts that glucose plays significant roles on up-regulation of laccase genes in planta and higher activity of laccase in H. annosum s.s.. Taking all together, laccases in H. annosum s.s. have diverse functions and a group of laccases may play a role during interactions with Scots pine seedlings.     

中国台湾孔头舌虫新种的发现及其致病特征

目的?摇探讨中国台湾孔头舌虫新种(Porocephalus taiwana sp. nov.)的形态与致病特征及新病种的病原学诊断方法。 方法 用患者稀便用粪便沉淀浓集法收集粪中若虫鉴定虫种，并结合临床资料作统计分析，以确定此新种所致疾病的临床特征。 结果 发现了舌形虫病的一种致病新种，即为台湾孔头舌虫，其所致的疾病称台湾孔头舌虫病。根据本例的发现，提出传统的内脏舌形虫病可分为2个亚型，成囊亚型和脱囊亚型。根据其病理学特征，本病例属于脱囊型内脏舌形虫病。 结论 描述了台湾孔头舌虫新种，其所致的台湾孔头舌虫病属于一种新型脱囊亚型性内脏舌形虫病。     

产毒性大肠杆菌对豚鼠致病性的实验研究

目的 试图通过产毒性大肠杆菌（ＥＴＥＣ）对豚鼠致病性的实验研究,进一步探讨该菌的致病机理。方法 利用人源性ＥＴＥＣ菌株Ｅ４４８１３、Ｅ４４８１５、Ｅ４４８２２和Ｅ４４８２３攻击豚鼠,造成豚鼠ＥＴＥＣ感染模型,观察豚鼠ＥＴＥＣ感染的病变特点。结果 ４株ＥＴＥＣ菌株均能造成豚鼠发病,以Ｅ４８１３致病性最大。ＥＴＥＣ能定植于豚鼠肠道至少达１４天。发病豚鼠肠肠明显充血、肿胀、以回肠为最严重。敏感组无发病症     

Pathogenicity and transmissibility of three avian influenza A (H5N6) viruses isolated from wild birds

Since 2013, highly pathogenic H5N6 avian influenza viruses (AIVs) have emerged in poultry and caused sporadic human infections in Asia. The recent discovery of three new avian H5N6 viruses – A/oriental magpie-robin/Guangdong/SW8/2014 (H5N6), A/common moorhen/Guangdong/GZ174/2014 (H5N6) and A/Pallas's sandgrouse/Guangdong/ZH283/2015 (H5N6) – isolated from apparently healthy wild birds in Southern China in 2014–2015 raises great concern for the spread of these highly pathogenic AIVs (HPAIVs) and their potential threat to human and animal health. In our study, we conducted animal experiments and tested their pathogenicity in ducks, chickens and mice. Ducks can carry and shed the H5N6 HPAIVs, but show no ill effects. On the other hand, these H5N6 HPAIVs can efficiently infect, transmit and cause death in chickens. Due to the overlap of habitats, domestic ducks play an important role in circulating AIVs between poultry and wild birds. Our results raise the possibility that wild birds disseminate these H5N6 HPAIVs to poultry along their flyways and thus pose a great threat to the poultry industry. These viruses are also highly pathogenic to mice, suggesting they pose a potential threat to mammals and, thus, public health. One virus isolated in 2015 replicates much more efficiently and is more lethal in these animals than the two other viruses isolated in 2014. It seems that the H5N6 viruses tend to be more lethal as time passes. Therefore, it is necessary to vigilantly monitor H5N6 HPAIVs in wild birds and poultry.     

腹泻便中成团肠杆菌的分离与鉴定

本文报告了自腹泻便中检出的13株成团肠杆菌生化鉴定,分子生物学检测,药敏试验及致病性研究结果。生化鉴定结果与文献基本相符,分子生物学检测该组细菌DNA同源性为72％～100％,证明是同种细菌。致病性研究发现部分菌株可引起动物和生物模型病变,与人的腹泻关系密切,14种药物敏感试验说明该组细菌的抗药谱很广,临床上可用的敏感药物不多,发生感染后治疗将十分困难。     

Cloning and further sequence analysis of the spike gene of attenuated porcine epidemic diarrhea virus DR13

The spike (S) gene of the attenuated porcine epidemic diarrhea virus (PEDV) DR13 was cloned and sequenced to further explore the functions of wild type PEDV and attenuated PEDV. Sequencing revealed a single large ORF of 4,149 nucleotides encoding a protein of 1,382 amino acids with predicted M _r of 151 kDa. The coding region of the S gene of attenuated PEDV DR13 had 20 nucleotide changes that appeared to be significant determinants of function in that they produced changes in its predicted amino acid sequence. Notably, attenuated PEDV DR13 has previously been found to exhibit reduced pathogenicity in pigs. The regions containing these 20 nucleotide changes may therefore be crucial for PEDV pathogenicity. The attenuated PEDV DR13 S protein contains 28 Asn-Xaa-Ser/Thr sequons, 21 asparagines that are predicted to be N-glycosylated and a stretch of highly hydrophobic residues at positions 1,327–1,347, which is predicted to form an α-helix and to function as a membrane anchor. One (from N to K at 378) of the changes in the deduced amino acid sequence destroyed N-linked glycosylation sites, while another change (from N to S at 114) created a new one at a different location. These alterations in N-linked glycosylation sites reflected 3 nucleotide changes, which were related to the above-mentioned nucleotide changes and are suggested to influence the pathogenicity of attenuated PEDV DR13. Attenuated PEDV DR13 has 96.5, 96.4, 96.1, 93.9, 93.5 and 96.6% DNA sequence identities with CV777, Br1/87, JS-2004-2, Spk1, Chinju99 and parent DR13, respectively. Likewise, it shares 95.7, 95.4, 95.6, 92.0, 91.6 and 95.7% identity with those genes at the deduced amino acid sequence level. Phylogenetic analysis suggested that attenuated PEDV DR13 is closely related to CV777, Br1/87, JS-2004-2 and parent DR13, rather than to Spk1 and Chinju99 and is especially close to the Chinese PEDV strain JS-2004-2. Nucleotide sequence data reported is available in the GenBank database under the Accession Nos. DQ462404 and DQ862099.     

Molecular characterization of three novel murine noroviruses

Murine noroviruses (MNV) comprise a group of newly recognized pathogens infecting laboratory mice. The first reported murine norovirus, murine norovirus 1 (MNV-1), produces a transient infection with a short duration of fecal shedding after infection of immunocompetent laboratory mice. Our laboratory subsequently isolated three novel murine noroviruses, murine norovirus 2 (MNV-2), murine norovirus 3 (MNV-3), and murine norovirus 4 (MNV-4), that have markedly different pathogenicity from MNV-1 by producing persistent infections and prolonged fecal shedding in infected immunocompetent mice. In this study, the nucleotide sequences and the predicted amino acid sequences of the three novel murine noroviruses were determined and compared to each other, MNV-1, and other previously described human and animal noroviruses. The three novel murine norovirus strains were shown to be related to each other and MNV-1 by sequence and phylogenetic analysis even though MNV-2, MNV-3 and MNV-4 all display markedly different biologic behavior from that of MNV-1. The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers DQ223041, DQ223042, and DQ223043.