应用寡核苷酸芯片并行检测CYP1A和GSTM1基因多态性

利用寡核苷酸芯片检测方法分析CYP1A单核苷酸多态性(SNP)和GSTM1缺失与否,实验结果证明了寡核苷酸芯片技术可并行、准确、高效地检测基因的单核苷酸多态性和其他类型的基因多态型,可为疾病遗传易感性及单体型的研究提供强有力的研究工具。采用该寡核苷酸芯片,检测了84份正常人的血液DNA样本,其中GSTMl基因缺失率达到47．6％,接近报道数值。统计分析发现,CYP1A m1-m2的3种基因型组合TT-AG、TT-GG和TC-GG的发生频率都为0,而根据实验得到的m1和m2各自基因型数据计算,它们的发生频率应是11．4％、2．6％和3．1％,所以推测在所检测的样本中没有T(m1位点)和G(m2位点)的连锁组合,即m1和m2位点的组合只有3种单体型：T-A、C-A和C-G,其发生频率分别是69．6％、7．7％和22．6％。     

CYP1A1基因单核苷酸多态性与肺癌的相关性研究

目的:探讨代谢酶CYP1A1基因MspI位点多态性与新疆汉族人群肺癌遗传易感性之间的相关性.方法:应用聚合酶链式反应(PCR)-限制性片段长度多态性(RFLP)技术检测59例新疆汉族肺癌和84例新疆汉族健康人的CYP1A1基因MspI位点多态性分布频率,并分析了CYP1A1基因MspI位点多态性与新疆汉族人群肺癌遗传易感性和患者性别之间的相关性.结果:(1)CYP1A1基因MspI位点3种多态基因型分布频率在两组间比较差异有统计学意义(χ2=6.682,P=0.035),CC基因型在病例组的分布频率显著高于正常对照组.(2)携带突变CC基因型的个体较携带TT基因型的个体患肺癌的危险性增加(OR=3.759.95%CI=1.228-11.494,P=0.035).(3)男女肺癌患者的CYP1A1基因MspI位点基因型及等位基因频率的差异均无显著性(P>0.05).结论:(1)CC突变基因型可能是新疆汉族人群的肺癌易感因素.(2)CYP1A1基因MspI位点多态性可能与新疆汉族肺癌患者的性别无关.     

中国湖南人群GSTM1和GSTT1基因多态性与肺癌易感性关系的研究

应用病例-对照分析研究(对照组205例,肺癌病例组104例),抽提静脉血基因组DNA,采用PCR及多重PCR方法,检测谷胱甘肽转移酶GSTM1和GSTT1单独及联合缺失基因型的遗传多态性在中国湖南人群中肺癌患者和正常人群体中的分布,探讨这些多态性基因型与肺癌易感性的关系.结果显示GSTM1-/-基因型在湖南地区居民肺癌群体和正常对照人群中的频率分别为62.5%和46.3%(P<0.05);肺癌患者组GSTT1-/-基因型的频率(66.3%)显著高于正常对照组(42.4%)(P<0.05).GSTM1-/-和GSTT1-/-联合基因型在肺癌组和正常对照组中的频率分别为41.3%和22.4%(P<0.05).SPSS11.5软件统计学分析表明,这些基因型在肺癌患者组和正常对照组人群中的发生频率具有显著性差异.由此可知GSTM1基因缺失和GSTT1基因缺失分别与肺癌的易感性相关;GSTM1和GSTT1基因联合缺失与肺癌的发生和发展呈现显著正相关.     

粘蛋白MUC1 568A/G SNP与辽宁地区人群胃癌遗传易感性的关系

为了探讨粘蛋白(MUC1)基因568位点A/G单核苷酸多态性与胃癌遗传易感性的关系, 采用序列特异性引物-聚合酶链反应(Sequence specific primers PCR, PCR-SSPs)检测来自辽宁地区人群138例胃癌患者及与其配比的131例对照个体MUC1 568 位点A/G多态性, 以ELISA法检测血清H. pylori IgG抗体。结果显示:(1)对照人群MUC1基因568位点AA、AG、GG 3种基因型分布频率分别为73.3%、22.1%、4.6%; (2)胃癌组MUC1 AA基因型携带频率显著高于正常对照组(P=0.03), 携带MUC1 AA基因型个体胃癌的发病风险增高到1.92倍; (3)以MUC1 AG+GG基因型并血清幽门螺杆菌(H. pylori)IgG抗体阴性的个体为对照, AG+GG基因型并H. pylori IgG抗体阳性个体、AA基因型并H. pylori IgG抗体阴性个体、AA基因型并H. pylori IgG抗体阳性个体胃癌患病风险增高, 但3组各组间差异均无统计学意义(P>0.05)。说明MUC1基因568位点A/G多态与胃癌的遗传易感性相关; MUC1 A/G基因多态性和H. pylori感染在胃癌发生发展过程未见交互作用。     

中国北方人群TCF7L2 基因多态性与血脂谱的相关性

目的:研究中国北方人群TCF7L2基因rs11196218和rs290487多态性的分布特点及其与血脂谱的相关性。方法:对1255例中国北方人群TCF7L2基因进行单核苷酸多态性检测,同时检测其血脂水平,分析血脂水平与上述基因的相关性。结果:在中国北方人群中TCF7L2基因rs11196218位点AA,AG和GG基因型频率分别为6.61%,39.68%和53.71%,等位基因A、G频率分别为26.45%和73.55%;而rs290487位点TT,CT和CC基因型频率分别为37.45%,45.98%和16.57%,等位基因T,C频率分别为60.44%和39.56%。rs11196218A/G与血清低密度脂蛋白、总胆固醇水平具有相关性(P≤0.05),而rs290487C/T与血脂水平无相关性(P0.05)。结论:在中国北方人群中存在TCF7L2基因rs11196218A/G和rs290487C/T单核苷酸多态性,且其变异频率大,rs11196218A/G与血脂异常相关。     

吉富罗非鱼IGF2基因分离及其单核苷酸多态性与体型、增重相关性

胰岛素样生长因子2(insulin-like growth factor2,IGF2)是控制动物生长和脂肪沉积的重要基因之一。本文采用PCR方法分离了吉富罗非鱼(GIFT strain Nile tilapia Oreochromis niloticus)IGF2基因5475bp,包含由4个外显子组成的整个阅读框669bp以及3个内含子。通过比对吉富罗非鱼10个个体IGF2序列,共发现11处单核苷酸多态性(single nucleotide polymorphism,SNP)位点,本文检测了内含子1的621nt(C/T)和外显子3的161nt(A/G)两位点在192尾吉富罗非鱼中的基因型分布,并分析不同基因型与体型、增重的相关性。使用四引物扩增受阻体系PCR检测内含子1的621nt基因型,结果显示,CC、CT、TT基因型频率在雄鱼中分别为0.32、0.32、0.36,在雌鱼中分别为0.38、0.38、0.24;与体型、增重的相关性分析表明,此位点不同基因型只与雄鱼体型(体高/体长)显著相关(P0.05),CC型个体显著高于CT和TT型个体。外显子3的A/G转换导致了MSPⅠ酶切位点改变,使用PCR-RFLP法检测该位点基因型,结果显示整个群体中不存在AA基因型,在雄鱼中,GG、AG基因型频率分别为0.71、0.29,而雌鱼中则为0.75和0.25;与体型、增重的相关性分析表明,此位点不同基因型只与雄鱼增重极显著相关(P0.01),GG型的雄鱼明显较AG型增重快。     

BRCA1 基因启动子区SNPs 与散发性乳腺癌易感性的相关研究

目的:探讨BRCA1基因启动子区rs11655505、rs73625095位点单核苷酸多态性与散发性乳腺癌易感性的关系。方法:采用ASA-PCR方法对200例乳腺癌患者(均经病理确诊)及200例正常女性BRCA1基因启动子区rs11655505(A/G)、rs73625095(A/G)位点单核苷酸多态性(SNP)进行分析,并将其PCR产物进行测序。结果:乳腺癌患者BRCA1基因启动子区rs11655505位点的A/G基因型频率为75%,显著高于正常人的40%;A/A基因型频率为7%,G/G基因型频率为18%,分别低于正常人的30%、30%。此位点的A或G等位基因在乳腺癌病例组及对照组中均无差别(x2=2.427,P=0.119);rs73625095位点的A/G基因型频率为68%,显著高于正常人的15%;G/G基因型频率为32%,低于正常人的84%;乳腺癌病例组中BRCA1基因启动子区rs11655505、rs73625095位点的A/G基因型与淋巴结转移与否相比,差别均有统计学意义(x2=7.321,P=0.026、x2=4.782,P=0.029)。结论:BRCA1基因rs11655505位点、rs736...     

贵州从江侗族威宁彝族、荔波瑶族谷胱甘肽S-转移酶M l、Tl 和Pl 的基因多态性研究

目的：研究贵州从江侗族、威宁彝族、荔波瑶族的GSTs基因多态性。方法：在隔离自然人群中,采用多重等住基因特异聚合酶链反应方法分析GSTM1和GSTT1基因多态性,同时采用PCR-RFLP的方法和TaqMan-MGB探针基因分型方法分析GSTP1（A1578G）基因多态性。结果：贵州从江侗族、成宁彝族、荔波瑶族的GSTM1和GSTT1纯合缺失基因型频率分别为59．6％～71．2％、39．4％～72.5％。其GSTP1（A1578G）基因型频率分别为：野生型（AA）为63.3％～75％、杂合子（AG）为23.2％～35．8％、纯合突变型（GG）为0～1.9％。等位基因频率：A为81．2％～86．6％,G为13．4％～18.8％。结论：贵州从江侗族、威宁彝族、荔波瑶族的GSTM1纯合缺失基因型频率在民族间差异无统计学意义,GSTP1（A1578G）基因型频率和等住基因频率在民族间差异无统计学意义,且其等位基因频率均符合Hardy-Weinberg平衡,但其GSTT1纯合缺失基因型频率在民族间差异有统计学意义（P〈0．05）。     

BRCA1基因启动子区SNPs与散发性乳腺癌易感性的相关研究（英文）

目的：探讨BRCA1基因启动子区rs11655505、rs73625095位点单核苷酸多态性与散发性乳腺癌易感性的关系。方法：采用ASA-PCR方法对200例乳腺癌患者（均经病理确诊）及200例正常女性BRCA1基因启动子区rs11655505（A/G）、rs73625095（A/G）位点单核苷酸多态性（SNP）进行分析,并将其PCR产物进行测序。结果：乳腺癌患者BRCA1基因启动子区rs11655505位点的A/G基因型频率为75%,显著高于正常人的40%;A/A基因型频率为7%,G/G基因型频率为18%,分别低于正常人的30%、30%。此位点的A或G等位基因在乳腺癌病例组及对照组中均无差别（x2=2.427,P=0.119）;rs73625095位点的A/G基因型频率为68%,显著高于正常人的15%;G/G基因型频率为32%,低于正常人的84%;乳腺癌病例组中BRCA1基因启动子区rs11655505、rs73625095位点的A/G基因型与淋巴结转移与否相比,差别均有统计学意义（x2=7.321,P=0.026、x2=4.782,P=0.029）。结论：BRCA1基因rs11655505位点、rs73625095位点的A/G基因型可能与散发性乳腺癌的发生相关,而且与有无发生淋巴结转移密切相关。rs73625095位点A和G等位基因可能为散发性乳腺癌发生的遗传危险因素。     

亚甲基四氢叶酸还原酶基因C677T、G1793A单核苷酸多态性与散发性乳腺癌易感性的关系

目的：研究亚甲基四氢叶酸还原酶（MTHFR）基因C677T、G1793A位点单核苷酸多态性与散发性乳腺癌易感性关系。方法：采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法,对200例乳腺癌患者及200例正常对照者MTHFR基因C677T、G1793A位点单核苷酸多态性进行分析,logistic回归分析不同基因型与乳腺癌风险的关系。结果：乳腺癌组MTHFR 677TT基因型频率为25.00%显著高于正常对照组的10.50%（X2=14.401,P=0.001）,CT基因型频率为44.50%低于正常对照组的54.50%,CC基因型频率在乳腺癌组和正常对照组中无差别;MTHFR 1793GA基因型频率为18.50%显著高于正常对照者的8.50%（X2=8.563,P=0.003）。乳腺癌患者MTHFR 677T和1793A等位基因频率分别为47.25%、9.25%,显著高于对照组中的37.75%、4.25%。MTHFR 677TT基因型携带者罹患乳腺癌的风险是677CC基因型携带者的2.732倍（95%CI=1.418～5.051,P=0.001）,MTHFR1793GA基因型携带者罹患乳腺癌的风险是1793GG基因型携带者的2.444倍（95%CI=1.325～4.505,P=0.003）。另外,乳腺癌组中MTHFR C677T基因多态性与肿瘤大小相关（x2=7.431,P=0.024,MTHFR G1793A基因多态性与淋巴结转移情况（x2=8.939,P=0.011）、癌组织学分级（x2=9.983,P=0.007）相关。结论：MTHFR C677T、G1793A基因多态性与散发性乳腺癌的易感性相关。     

Modulation of UDP-glucuronosyltransferase 1A1 in primary human hepatocytes by prototypical inducers

The primary objective of this study was to evaluate the modulation of UGT1A1 expression in human hepatocytes using prototypical CYP450 inducers. A bank of 16 human livers was utilized to obtain an estimate of the range of UGT1A1 protein expression and catalytic activity. Concentration-dependent changes in UGT1A1 response were evaluated in hepatocyte cultures after treatment with 3-methylchloranthrene, beta-napthoflavone, rifampicin, or phenobarbital. Pharmacodynamic analyses of UGT1A1 expression were conducted and compared to those of CYP450 after treatment with inducers in 2-3 different hepatocyte preparations. Additionally, expression of UGT1A1 mRNA and protein was evaluated in human hepatocytes treated with 14 different compounds known to activate differentially the human pregnane-X-receptor or constitutive androstane receptor. Pharmacodynamic modeling revealed EC50 values statistically significant between UGT1A1 and CYP2B6 after treatment with PB, but not statistically distinguishable between UGT1A1 and CYP's 1A2 or 3A4 after treatment with 3-methylchloranthrene or rifampicin, respectively. UGT1A1 was most responsive to the pregnane-X-receptor-agonists rifampicin, ritonavir, and clotrimazole at the mRNA level and, to a lesser extent, the constitutive androstane receptor-activators, phenobarbital and phenytoin. Pharmacodynamic analyses support a mechanism of coordinate regulation between UGT1A1 and a number of CYP450 enzymes by multiple nuclear receptors.     

cDNA cloning and characterization of feline CYP1A1 and CYP1A2

Deficiency of drug glucuronidation in the cat is one of the major reasons why this animal is highly sensitive to the side effects of drugs. The characterization of cytochrome P450 isoforms belonging to the CYP1A subfamily, which exhibit important drug oxidation activities such as activation of pro-carcinogens, was investigated. Two cDNAs, designated CYP1A-a and CYP1A-b, corresponding to the CYP1A subfamily were obtained from feline liver. CYP1A-a and CYP1A-b cDNAs comprise coding regions of 1554 bp and 1539 bp, and encode predicted amino acid sequences of 517 and 512 residues, respectively. These amino acid sequences contain a heme-binding cysteine and a conserved threonine. The cDNA identities, as well as the predicted amino acid sequences containing six substrate recognition sites, suggest that CYP1A-a and CYP1A-b correspond to CYP1A1 and CYP1A2, respectively. This was confirmed by the kinetic parameters of the arylhydrocarbon hydroxylase and 7-ethoxyresorufin O-deethylase activities of expressed CYPs in yeast AH22 cells and by the tissue distribution of each mRNA. However, theophylline 3-demethylation is believed to be catalyzed by CYP1A1 in cats, based on the high V(max) and low K(m) seen, in contrast to other animals. Because feline CYP1A2 had a higher K(m) for phenacetin O-deethylase activity with acetaminophen, which cannot be conjugated with glucuronic acid due to UDP-glucuronosyltransferase deficiency, it is supposed that the side effects of phenacetin as a result of toxic intermediates are severe and prolonged in cats.     

Alpha-synuclein overexpression negatively regulates insulin receptor substrate 1 by activating mTORC1/S6K1 signaling

Alpha-synuclein (α-Syn) is a major component of Lewy bodies, a pathological feature of Parkinson's and other neurodegenerative diseases collectively known as synucleinopathies. Among the possible mechanisms of α-Syn-mediated neurotoxicity is interference with cytoprotective pathways such as insulin signaling. Insulin receptor substrate (IRS)-1 is a docking protein linking IRs to downstream signaling pathways such as phosphatidylinositol 3-kinase/Akt and mammalian target of rapamycin (mTOR)/ribosomal protein S6 kinase (S6K)1; the latter exerts negative feedback control on insulin signaling, which is impaired in Alzheimer's disease. Our previous study found that α-Syn overexpression can inhibit protein phosphatase (PP)2A activity, which is involved in the protective mechanism of insulin signaling. In this study, we found an increase in IRS-1 phosphorylation at Ser636 and decrease in tyrosine phosphorylation, which accelerated IRS-1 turnover and reduced insulin-Akt signaling in α-Syn-overexpressing SK-N-SH cells and transgenic mice. The mTOR complex (C)1/S6K1 blocker rapamycin inhibited the phosphorylation of IRS-1 at Ser636 in cells overexpressing α-Syn, suggesting that mTORC1/S6K1 activation by α-Syn causes feedback inhibition of insulin signaling via suppression of IRS-1 function. α-Syn overexpression also inhibited PP2A activity, while the PP2A agonist C2 ceramide suppressed both S6K1 activation and IRS-1 Ser636 phosphorylation upon α-Syn overexpression. Thus, α-Syn overexpression negatively regulated IRS-1 via mTORC1/S6K1 signaling while activation of PP2A reverses this process. These results provide evidence for a link between α-Syn and IRS-1 that may represent a novel mechanism for α-Syn-associated pathogenesis.     

Induction of monocyte chemoattractant protein-1 release from A549 cells by agonists of protease-activated receptor-1 and -2

Hypersecretion of cytokines and serine proteases has been observed in asthma. However, the influence of proteases and protease-activated receptors (PARs) on monocyte chemoattractant protein-1 (MCP-1) release from airway epithelial cells remains largely unknown. In the present study, A549 cells were challenged with agonists of PARs, and levels of MCP-1 released in the supernatant and mRNA expression were examined by ELISA and real time polymerase chain reaction (PCR), respectively. The results show that thrombin, tryptase, elastase and trypsin induced an up to 6.5-, 1.8-, 1.6-, and 3.1-fold increase in MCP-1 release from A549 cells, respectively, following a 16-h incubation period. The protease-induced secretion of MCP-1 can be abolished by specific protease inhibitors. Agonist peptides of PAR-1 and PAR-2 stimulate MCP-1 secretion up to 15- and 12.7-fold, respectively. Real-time PCR showed that MCP-1 mRNA is up-regulated by the serine proteases tested and by agonist peptides of PAR-1 and PAR-2. In conclusion, serine proteases can stimulate MCP-1 release from A549 cells possibly through a PARs-related mechanism, suggesting that they are likely to contribute to MCP-1-related airway inflammatory disorders in man.     

某高校甲型H1N1 流感确诊病例流行病学分布特征分析

目的：通过了解某高校甲型H1N1 流感病例的流行病学分布特征,为预防和控制流感在高校的蔓延提供依据。方法：以某高 校2009 年11 月6 日至2009 年11 月24 日发病并确诊的74 例甲型H1N1 流感病例为研究对象,分析并比较病例的年龄、性别、 学历层次、年级、专业、发病时间和临床症状。结果：74 例甲型H1N1 流感确诊病例均为学生,罹患率为1.63 %,其中男性占94.6 %,女性占5.4 %;病例平均年龄为20.5 岁± 2.2 岁;94.6 %的病例为本科生;本科生罹患率（4.03%）显著高于研究生（0.14%）;2006 级见习期本科生罹患率（11.05 %）显著高于其他年级学生;疫情的流行全距为19 天,发病高峰为2009 年11 月13 日至2009 年 11 月18 日;病例以发热、咳嗽、乏力、头疼等临床症状为主。结论：该高校甲型H1N1 流感确诊病例多为22岁以下的男性学生。本 研究提示加强见习学生的监测和管理、设立隔离宿舍、接种疫苗等有针对性的措施能够有效控制流感疫情在高校蔓延。     

Gene polymorphisms and serum levels of TL1A in patients with rheumatoid arthritis

Recent findings showed elevated expression of tumor necrosis factor (TNF)-like ligand 1A (TL1A) in rheumatoid arthritis (RA) patients and arthritis mice. However, whether TL1A gene polymorphisms may correlate with RA susceptibility needs to be discussed. This case-control study was performed on 350 RA patients and 556 healthy subjects to identify TL1A genetic variants (rs3810936, rs6478109, and rs7848647) and their possible association with TL1A levels, susceptibility to and severity of RA. Odds ratio and 95% confidence interval were calculated to represent the correlation between TL1A polymorphisms and RA. The TL1A serum levels were evaluated. Results showed that frequencies of TC, TT + TC genotypes of rs3810936, rs7848647 in RA patients were significantly lower in RA patients compared with controls. Patients with C allele showed more severe disease course (disease activity index: erythrocyte sedimentation rate, rheumatoid factor) than in carriers of T allele. However, the allele or genotype frequencies of rs6478109 were not associated with RA. In addition, TL1A genetic variants conferred higher TL1A levels in RA patients compared with controls. In conclusion, these findings indicated an association between TL1A rs3810936, rs7848647 variation and the susceptibility of RA in a sample of Chinese individuals, and TL1A may correlate with severity of RA.     

Phosphorylation of human phospholipase A1 DDHD1 at newly identified phosphosites affects its subcellular localization

Phospholipase A1 (PLA1) hydrolyzes the fatty acids of glycerophospholipids, which are structural components of the cellular membrane. Genetic mutations in DDHD1, an intracellular PLA1, result in hereditary spastic paraplegia (HSP) in humans. However, the regulation of DDHD1 activity has not yet been elucidated in detail. In the present study, we examined the phosphorylation of DDHD1 and identified the responsible protein kinases. We performed MALDI-TOF MS/MS analysis and Phos-tag SDS-PAGE in alanine-substitution mutants in HEK293 cells and revealed multiple phosphorylation sites in human DDHD1, primarily Ser8, Ser11, Ser723, and Ser727. The treatment of cells with a protein phosphatase inhibitor induced the hyperphosphorylation of DDHD1, suggesting that multisite phosphorylation occurred not only at these major, but also at minor sites. Site-specific kinase-substrate prediction algorithms and in vitro kinase analyses indicated that cyclin-dependent kinase CDK1/cyclin A2 phosphorylated Ser8, Ser11, and Ser727 in DDHD1 with a preference for Ser11 and that CDK5/p35 also phosphorylated Ser11 and Ser727 with a preference for Ser11. In addition, casein kinase CK2α1 was found to phosphorylate Ser104, although this was not a major phosphorylation site in cultivated HEK293 cells. The evaluation of the effects of phosphorylation revealed that the phosphorylation mimic mutants S11/727E exhibit only 20% reduction in PLA1 activity. However, the phosphorylation mimics were mainly localized to focal adhesions, whereas the phosphorylation-resistant mutants S11/727A were not. This suggested that phosphorylation alters the subcellular localization of DDHD1 without greatly affecting its PLA1 activity.     

Phosphatidylserine-Specific Phospholipase A1 is the Critical Bridge for Hepatitis C Virus Assembly

The phosphatidylserine-specific phospholipase A1(PLA1 A) is an essential host factor in hepatitis C virus(HCV)assembly. In this study, we mapped the E2, NS2 and NS5 A involved in PLA1 A interaction to their lumenal domains and membranous parts, through which they form oligomeric protein complexes to participate in HCV assembly. Multiple regions of PLA1 A were involved in their interaction and complex formation. Furthermore, the results represented structures with PLA1 A and E2 in closer proximity than NS2 and NS5 A, and strongly suggest PLA1 A-E2's physical interaction in cells. Meanwhile, we mapped the NS5 A sequence which participated in PLA1 A interaction with the C-terminus of domain 1. Interestingly, these amino acids in the sequence are also essential for viral RNA replication. Further experiments revealed that these four proteins interact with each other. Moreover, PLA1 A expression levels were elevated in livers from HCV-infected patients. In conclusion, we exposed the structural determinants of PLA1 A, E2, NS2 and NS5 A proteins which were important for HCV assembly and provided a detailed characterization of PLA1 A in HCV assembly.     

Genetic variation of the VP1 gene of the virulent duck hepatitis A virus type 1 (DHAV-1) isolates in Shandong province of China

To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1 (DHAV-1) isolates, the virulence, cross neutralization assays and the complete sequence of the virion protein 1 (VP1) gene of nine virulent DHAV-1 strains, which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007–2008, were tested. The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses (ELD₅₀s) and the median lethal doses (LD₅₀s), respectively. The results showed that the ELD₅₀s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10⁶/mL to 1.44 × 10⁷/mL, while the LD₅₀s were 2.39 × 10⁵/mL to 6.15 × 10⁶/mL. Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates, respectively. Compared with other virulent, moderate virulent, attenuated vaccine and mild strains, the VP1 genes of the 9 strains shared 89.8%–99.7% similarity at the nucleotide level and 92.4%–99.6% at amino acid level with other DHAV-1 strains. There were three hypervariable regions at the C-terminus (aa 158–160, 180–193 and 205–219) and other variable points in VP1 protein, but which didn’t cause virulence of DHAV-1 change.