广西14市猪戊型肝炎的分子流行病学分析

为调查广西猪戊型肝炎(HE)的感染情况,本研究应用套式RT-PCR方法对采自广西14市43个猪场的508份3月龄左右猪只粪样及市售182份猪肝扩增猪戊型肝炎病毒(HEV)ORF2基因特异序列,并进行核苷酸序列同源性分析及遗传进化分析。结果表明,在508份猪粪样中194份可以检测到HEV RNA,阳性率为38.2%;182份猪肝样本中,33份可检测到HEV RNA,阳性率为18.1%;43个猪场中检出HEV RNA的有35个,猪场阳性率为81.4%。所获取的39株广西猪HEV ORF2基因特异序列同源性为89.9%～100%,提示在所调查的广西猪场中已较普遍存在HEV感染,所获取的39株广西HEV阳性样品均属于基因Ⅳ型。本研究结果佐证了感染猪及市售带毒猪肝脏是HEV重要的储存库和传染源,应该重视其公共卫生学意义,预防粪-口途径或者食源性HEV感染。     

新疆羊粪便戊型肝炎病毒RNA的检测与序列分析

【目的】为了了解新疆地区羊群中是否存在戊型肝炎的感染,我们从戊型肝炎病毒(Hepatitis E virus,HEV)IgG检测阳性的新疆某羊场采集54份1-3岁的羊粪便,【方法】利用逆转录套式聚合酶链方法(RT-nPCR),检测HEVRNA,其中6份为阳性,阳性率11.11%。【结果】将PCR扩增产物克隆,测序并进行序列分析,结果表明,6株羊源HEV检测株在HEV ORF2 189bp 99.38%-100%,为同一基因型;与HEVⅠ、Ⅱ、Ⅲ和Ⅳ型的同源性分别为78.67%-85.33%、81.33%-82.67%、78.67%-84.00%和84.67%-95.36%,与Ⅳ型最高同源性达94.04%-95.36%。以该189bp片段绘制进化树,发现与新疆牛源分离株、中国大陆猪源分离株(FJ610232)和中国大陆人源分离株(AJ272108)在同一分枝上,同属基因Ⅳ型;【结论】提示新疆羊群中可能存在HEV感染,并且羊可能是人类HEV传染源中除猪之外的新宿主。     

猪戊型肝炎病毒swCH-GS189株ORF2基因的克隆及序列分析

为进行猪戊型肝炎病毒(HEV)ORF2基因特征研究,参照GenBank中已发表的戊型肝炎病毒(HEV)核酸序列,设计了一对扩增HEV ORF2基因的引物,利用RT-PCR等方法克隆出了一株猪戊型肝炎病毒甘肃分离株GS189的ORF2基因cDNA片段.序列测定结果表明,swCH-GS189株的ORF2基因长2 025 bp,编码674个氨基酸,与GenBank中公布的其它毒株间的核苷酸序列同源性为79.1%～91.8%,推导的氨基酸序列同源性为89.5%～98.8%.系统发育进化树结果表明,该分离株为基因IV型.     

新疆奶牛戊型肝炎病毒RNA检测及序列分析

从新疆两个奶牛场的戊型肝炎病毒(Hepatitis E virus,HEV)抗体检测阳性的奶牛中分别采集牛粪便或肛拭子样品,利用反转录套式聚合酶链反应(RT-nPCR)检测所采集样品中的HEV RNA,结果来自第一个奶牛场的7份牛粪便样品为阳性,阳性率11.67%,来自第二奶牛场的1份肛拭子样品为阳性,阳性率为3.23%。将PCR扩增产物克隆、测序并进行序列分析,结果表明,对应于HEV ORF2 189bp核苷酸序列的8个牛源HEV基因组扩增片段的同源性为96.3%~100.0%,应当属于相同的基因型;它们与HEV 1、2、3和4型ORF2 189bp核苷酸平均同源性分别为78.5%~86.4%,81.7%~83.8%,79.1%~85.3%和84.3%~95.8%,与4型的同源性最高达93.2%~95.8%。基于这些已测序核酸片段绘制的基因进化树显示:本研究中的8株牛源HEV ORF2 189bp核苷酸序列与HEV 4型人源C5株、猪源swC3与swXJ株位于同一进化枝上,同属HEV基因4型,提示新疆奶牛中可能存在HEV感染,并且奶牛可能是人类HEV传染源中除猪之外的新宿主。     

戊型肝炎病毒研究新进展

戊型肝炎病毒(hepatitis E virus,HEV)是引起全球多地区大规模流行和散发病例的急性病毒性肝炎的病原体,发展中国家尤为突出;我国是戊型肝炎(hepatitis E,HE)流行的高发区.HE是一种人畜共患病,猪是人HEV病毒的主要储库,因而HE已成为一个全球性的的公共卫生问题.对HEV的病毒学和基因组特征、临床表征、流行病学、主要抗原表位以及HEV诊断试剂和疫苗研制的进展进行了综述.     

上海部分地区戊型肝炎病毒(HEV)基因型的分析

为了解戊型肝炎病毒(HEV)在上海部分地区流行的基因型,采用RT-nPCR的方法检验35例急性散发性戊型肝炎患者中HEV RNA,并对阳性产物进行克隆测序,然后对其基因型进行分析.结果显示在35例急性散发性戊型肝炎患者中PCR阳性为9例,测序证实8例为HEV的基因序列;其中1例为HEV 1型,7例为HEV 4型.提示在上海部分地区的急性散发性戊型肝炎中以HEV 4型感染为主.     

新疆猪粪便戊型肝炎病毒RNA的检测及序列分析

从戊型肝炎病毒(Hepatitis E virus,HEV)IgG检测阳性的新疆某猪场采集70份猪粪便,利用逆转录套式聚合酶链方法(RT-nPCR),检测HEV RNA,其中13份为阳性,阳性率18.57%.将PCR扩增产物克隆到pMD18-T载体上,构建成重组质粒并测序,结果表明,13株猪源HEV分离株在HEV ORF2 348bp核苷酸序列的同源性为97.1%～100%,为同一基因型;与HEV Ⅰ、Ⅱ、Ⅲ、Ⅳ的同源性分别为74.1%～77.6%,71.6%～74.1%,73.3%～78.2%和82.8%～91.4%,与ⅣA亚型的同源性同源性最高达89.4%～91.4%.以该核苷酸片段绘制的基因进化树显示13株猪源HEV与HEVⅣT1株在同一分支上,属基因Ⅳ型;与国内其他猪源HEV分离株该片段核苷酸序列的同源性为82.6%～91.3%,提示中国猪源HEV的基因型比较一致,同属HEVⅣ型.     

戊型肝炎病毒感染实验室诊断方法研究进展

戊型肝炎是由戊型肝炎病毒(Hepatitis E Virus,HEV)引起的急性病毒性肝炎,已经成为威胁人群健康的公共卫生问题。HEV主要通过消化道传播,但随着HEV输血传播病例的报道,HEV给输血安全带来的风险也受到人们的重视。通过分析戊型肝炎现有的诊断手段,以对献血员的HEV筛查提供借鉴作用,这对输血安全中戊型肝炎的预防和控制具有重大意义。目前常用的戊型肝炎检测指标主要包括:HEV RNA、HEV抗原、抗-HEV IgM、抗-HEV IgG。核酸检测是戊型肝炎诊断的"金标准",对于慢性戊型肝炎患者、免疫缺陷人群及无肝炎症状的HEV感染者都有着特别优势。HEV抗原作为HEV现症感染指标,对于血站HEV筛查和急性戊型肝炎诊断有很好的应用价值。抗-HEV IgM是HEV近期感染的标志,不能作为HEV现症感染的单一指标。而抗-HEV IgG只能指示HEV既往感染,不适用于急性戊型肝炎的诊断。目前,献血员HEV检测主要以核酸检测为基础,而HEV抗原检测可能弥补HEV RNA的检测不足。在未来,抗原检测和抗体检测对于献血员HEV筛查的价值还有待更多的研究评价。     

慢性戊型肝炎治疗的新进展

戊型肝炎(hepatitis E,HE)是由戊型肝炎病毒(hepatitis E virus,HEV)感染引起的一类病毒性肝炎。自从20世纪80年代HEV被发现以来,近30年里人们对戊型肝炎的研究不断深入。戊型肝炎通常是一种自限性疾病,但最近研究发现免疫力低下的人群,如人类免疫缺陷病毒感染者、器官移植接受者或者接受免疫抑制治疗的恶性肿瘤患者等感染HEV,甚至普通人感染后,均可能发展为慢性戊型肝炎(chronic hepatitis E,CHE)。然而,目前国际上尚无治疗慢性戊型肝炎的特异性药物及方法,本文将对国内外临床上慢性戊型肝炎的治疗方法及潜在药物作一综述。     

戊型肝炎病毒Ⅳ型ORF2蛋白在汉逊酵母中的表达

为了寻求新型表达系统来研制戊型肝炎基因工程疫苗,利用甲基营养型汉逊酵母(Hansenulapolymorpha)系统表达戊型肝炎病毒(HepatitisEvirus,HEV)Ⅳ型结构区ORF2编码蛋白第112-607氨基酸片段。为实现目的基因在汉逊酵母中的高效表达,根据汉逊酵母偏爱密码子优化设计目的基因,用搭桥PCR法合成优化后的基因序列,并克隆到多拷贝表达载体上,转化汉逊酵母营养缺陷宿主菌ATCC26012(Ura3-),在选择培养基上培养,运用PCR法筛选得到携带外源基因的重组菌株,然后用含甲醇的培养基诱导表达,对表达产物进行SDS-PAGE、ELISA和Westernblot检测和鉴定。SDS-PAGE实验结果表明目的蛋白分子量约为56kD,表达量占菌体总蛋白的12%;ELISA检测结果表明表达产物为具有免疫反应性的HEVORF2蛋白,ELISA效价最高可达1∶2048,目的蛋白表达量随着基因拷贝数的增加呈升高的趋势;Westernblot鉴别实验结果证实表达产物与HEV多抗有特异性抗原抗体结合反应。HEV结构区ORF2蛋白在汉逊酵母中的成功表达,为研制基因工程戊型肝炎疫苗奠定了基础。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.