人偏肺病毒广州分离株全基因组序列测定及分析

目的 探讨广州地区儿童感染的偏肺病毒基因组分子结构特点和基因型类型.方法 参考GenBank上的偏肺病毒00-1株(AF371337)基因组设计分段扩增引物,进行RT-PCR分段扩增偏肺病毒基因组,克隆于T载体上,序列测定,用Clustal W/X、DNASTAR、MEGA4.1等软件分析基因组序列.结果 偏肺病毒hMPVgz01全基因组为13 327 bp,提交到GenBank上的序列号为GQ153651,有8个开放阅读框(open reading frames,ORFs),基因组结构为:3-N-P-M-F-M2-SH-G-L-5;将hMPVgz01株全基因组核苷酸序列与GenBank上的偏肺病毒全基因组序列进行Clustal W比较,发现与偏肺病毒的A组相似性较高,为92%～97%,与A2b组的BJ1887相似性为最高,而与B组相似性为81%,与C组的禽偏肺病毒为71%.将hMPVgz01株的N、F、G基因与偏肺病毒的A1、A2、B1、B2的相对应基因进行相似性比较,同样也是与A2b型的相似性为最高,因此确认广州地区的hMPVgz01株为A2b型.结论 广州地区儿童感染的偏肺病毒hMPVgz01株全基因组序列为13 327 bp,GenBank 序列号为GQ153651,hMPVgz01与偏肺病毒的A2b型相似性最高,确认hMPVgz01株属于偏肺病毒A2b型.     

中国湖南地区人偏肺病毒的基因分型及其膜蛋白G基因特征的分析

目的 研究中国湖南地区人偏肺病毒(hMPV)的基因分型及其膜蛋白G序列的遗传学特征,比较分析其区域性流行特点.方法收集2005年中国湖南地区232份住院儿童鼻咽抽吸物(NPA)样本进行常见呼吸道病毒筛查,并扩增hMPV阳性样本的膜蛋白G全序列,与GenBank中已知hMPV参考株及其他地区公布的相关资料进行比对、进化等分子遗传学特征分析.结果从232份临床样本中共检测得到17份(7.3%)hMPV阳性样本,与其他病毒混合感染率达35%.扩增出其中13份hMPV样本的G蛋白全序列,分属于4种亚型(A1、A2、B1、B2).核酸长度类型有4种(711,675,660,696nt),N-连接糖基化位点数目和位置、半胱氨酸残基数目等特征与已报道的同期北京地区、日本、北美等地区hMPV调查分析结果不尽一致.结论中国湖南地区与其他地区同期hMPV调查分析结果各有特点,反映出hMPV变异显著,具有明显的地区流行特征.     

Epidemiology of human metapneumovirus

Since the discovery of human metapneumovirus (hMPV) in 2001, the virus has been identified worldwide. hMPV is a common respiratory pathogen, particularly in infants and young children. The virus is associated with both upper and lower respiratory tract infections and may be a trigger for asthma. At least two major genotypes of hMPV circulate during community outbreaks. Whether these genotypes represent distinct serotypes remains controversial. The major challenges faced by the medical and scientific communities are the understanding of the pathogenesis of hMPV disease and the development of a safe and effective vaccine to protect against infection and disease caused by this newly recognized respiratory virus.     

1型星状病毒上海分离株基因组序列测定及分析

目的 了解上海地区腹泻患儿感染的星状病毒基因组分子结构特点和基因型.方法 用RT-PCR方法分段扩增星状病毒基因组,克隆于pMD18-T载体上,测定序列并拼接,用MEGA、DNAStar软件对所得序列进行分析.结果 本次分离株基因组全长6807 bp,命名为HAstV-SH,提交到GenBank上的序列号为FJ375759,有3个开放阅读框架,非结构基因ORF1a、ORF1b共长4290 bp,位于基因组83～4372 nt之间;编码结构蛋白的ORF2基因全长2364 bp,位于基因组4764～6727 nt之间.与GenBank中星状病毒ORF2基因组序列同源性比较发现,HAstV-SH与1型星状病毒核苷酸同源性最高(97%),与其他基因型的同源性为63%～70%.结论 上海地区儿童感染的星状病毒HAstV-SH属于1型星状病毒,与日本分离株AB009985亲缘关系较近,氨基酸同源性为97.5%.     

Computational comparison of human genomic sequence assemblies for a region of chromosome 4

Much of the available human genomic sequence data exist in a fragmentary draft state following the completion of the initial high-volume sequencing performed by the International Human Genome Sequencing Consortium (IHGSC) and Celera Genomics (CG). We compared six draft genome assemblies over a region of chromosome 4p (D4S394-D4S403), two consecutive releases by the IHGSC at University of California, Santa Cruz (UCSC), two consecutive releases from the National Centre for Biotechnology Information (NCBI), the public release from CG, and a hybrid assembly we have produced using IHGSC and CG sequence data. This region presents particular problems for genomic sequence assembly algorithms as it contains a large tandem repeat and is sparsely covered by draft sequences. The six assemblies differed both in terms of their relative coverage of sequence data from the region and in their estimated rates of misassembly. The CG assembly method attained the lowest level of misassembly, whereas NCBI and UCSC assemblies had the highest levels of coverage. All assemblies examined included <60% of the publicly available sequence from the region. At least 6% of the sequence data within the CG assembly for the D4S394-D4S403 region was not present in publicly available sequence data. We also show that even in a problematic region, existing software tools can be used with high-quality mapping data to produce genomic sequence contigs with a low rate of rearrangements.     

人偏肺病毒研究进展

<正>人偏肺病毒(human metapneumovirus,hMPV)是新近发现的一种呼吸道致病病毒,2001年首次在荷兰一婴儿的鼻咽部抽吸物中被分离得到,根据它的形态学、生物化学以及基因学特点,hMPV一开始被分类为禽偏肺病毒,禽偏     

Seroprevalence of human metapneumovirus in Japan

A new human pneumovirus, provisionally designated human metapneumovirus, was discovered by Dutch researchers. We examined 142 serum samples from the general population aged from 1 month to 35 years in Japan for human metapneumovirus antibody by indirect immunofluorescence assays using human metapneumovirus-infected monkey kidney cells. The overall prevalence of human metapneumovirus infection was 72.5%. The seropositive rate was lowest in the age group of 6 months to 1 year and gradually increased with age. All of the children had been exposed to human metapneumovirus by the age of 10 years. The results show that human metapneumovirus is circulating in the Japanese population and is a ubiquitous virus acquired early in life.     

Ten years of human metapneumovirus research

Described for the first time in 2001, human metapneumovirus (hMPV) has become one of the main viral pathogens responsible for acute respiratory tract infections in children but also in the elderly and immuno-compromised patients. The pathogen most closely related to hMPV is human respiratory syncytial virus (hRSV), the most common cause of bronchiolitis and pneumonia in young children. hMPV has been classified into two main viral groups A and B and has a seasonal distribution in temperate countries with most cases occurring in winter and spring. Given the difficulties encountered in culturing hMPV in vitro, diagnosis is generally achieved using real-time polymerase chain reaction.Like other Paramyxoviridae, hMPV has a negative-sense single-stranded RNA genome that includes 8 genes coding for 9 different proteins. The genomic organization and functions of surface attachment and fusion glycoproteins are relatively similar to those of hRSV. Although many groups have studied the viral life cycle of hMPV, many questions remain unanswered concerning the exact roles of the viral proteins in the attachment, fusion and replication of hMPV.To date, there remains no approved modality to combat hMPV infections. The majority of treatments that have been tested on hMPV have already demonstrated activity against hRSV infections. Some innovative approaches based on RNA interference and on fusion inhibitors have shown efficacy in vitro and in animal studies and could be beneficial in treating human hMPV disease. Difficulties faced inducing a durable immune response represent the biggest challenge in the development of an effective hMPV vaccine. Several strategies, such as the use of live-attenuated viruses generated by reverse genetics or recombinant proteins, have been tested in animals with encouraging results.     

Analysis of primate genomic variation reveals a repeat-driven expansion of the human genome

We performed a detailed analysis of both single-nucleotide and large insertion/deletion events based on large-scale comparison of 10.6 Mb of genomic sequence from lemur, baboon, and chimpanzee to human. Using a human genomic reference, optimal global alignments were constructed from large (>50-kb) genomic sequence clones. These alignments were examined for the pattern, frequency, and nature of mutational events. Whereas rates of single-nucleotide substitution remain relatively constant (1-2 x 10(-9) substitutions/site/year), rates of retrotransposition vary radically among different primate lineages. These differences have lead to a 15%-20% expansion of human genome size over the last 50 million years of primate evolution, 90% of it due to new retroposon insertions. Orthologous comparisons with the chimpanzee suggest that the human genome continues to significantly expand due to shifts in retrotransposition activity. Assuming that the primate genome sequence we have sampled is representative, we estimate that human euchromatin has expanded 30 Mb and 550 Mb compared to the primate genomes of chimpanzee and lemur, respectively.     

Genomic analysis of four human metapneumovirus prototypes

Human metapneumovirus (HMPV) is an important cause of acute respiratory illness in children. We determined the complete genome sequence of four strains of HMPV representing each of the four lineages. These sequences were compared with published HMPV genome sequences. Most genes were conserved between the genetic lineages (79.5-99.6%), though nucleotide diversity was greater than amino acid diversity, suggesting functional constraints on mutation. However, the SH and G open reading frames were more variable (mean 76.4% and 59.0% aa identity, respectively), with mostly nonsynonymous changes, suggesting selective pressure on the SH and G proteins. Gene-start regions were largely conserved between genes and viruses, while gene-end sequences were conserved between viruses but not between genes. The SH-G and G-L intergenic regions were extremely long (～200 nt) and have no defined function, yet were highly conserved within major groups. These findings highlight broadly conserved regions of the HMPV genome and suggest unidentified biological roles for SH and G.     

Characterization of human metapneumovirus infections in Israel

Respiratory tract infections are a leading cause of morbidity and mortality worldwide. Even with the advancement of diagnostic tools, the causative agent of 20 to 30% of upper respiratory tract infections go undiagnosed. Recently, a newly identified human respiratory virus, human metapneumovirus (hMPV), was discovered in young children in The Netherlands. To study the prevalence of hMPV infections in Israeli children, respiratory specimens from 388 hospitalized children less than 5 years of age were evaluated for the presence of hMPV RNA, which was present in 42 (10.8%) of these samples. All hMPV-positive samples were negative for respiratory syncytial virus (RSV), influenza viruses (Flu) A and B, adenovirus, and parainfluenza viruses 1, 2, and 3. Conversely, hMPV RNA was not detected in 76 RSV-positive and 38 Flu A- or B-positive samples. Most hMPV activity was between the months February and April. Sequence analysis of 20 positive samples revealed that both of the hMPV genotypes (groups 1 and 2) have circulated in central Israel during the study period. Moreover, three of the four known hMPV subgroups (1A, 1B, and 2B) were detected among the tested samples. Seroprevalence of hMPV in 204 patients from the central part of Israel revealed that 100% of the children are hMPV seropositive by the age of 5 years old. We conclude that hMPV is a common respiratory pathogen in Israel, while mixed infections of hMPV with RSV or Flu in hospitalized children are apparently rare.     

Comparison of the seroprevalence of human metapneumovirus and human respiratory syncytial virus

Human metapneumovirus (hMPV) is a virus that induces human respiratory syncytial virus (hRSV)-like illnesses, ranging from upper respiratory tract infection to severe bronchiolitis and pneumonia. The 100 serum samples from children aged 1 month to 5 years were tested for the presence of hMPV and hRSV antibodies using an indirect immunofluorescence assay and a neutralizing-antibody assay, respectively. The seroprevalence of hMPV was significantly lower than that of hRSV in children over 4-months-old (43% vs. 60%, P < 0.025), and the difference was particularly notable between the ages of 4 months and 1 year (11% vs. 48%, P = 0.006). The results suggest that primary infection with hMPV occurs somewhat later than that with hRSV.     

Serosurvey of human metapneumovirus infection in Croatia

Aim

To assess the seroprevalence of human metapneumovirus (hMPV) in Croatia.

Methods

During 2005, a total of 137 serum specimens from Croatian patients aged from 6 days to 51 years, without respiratory symptoms, were collected at the Croatian National Institute of Public Health. The sera were examined using the indirect immunofluorescent assay.

Results

The overall hMPV seropositivity rate in the samples tested was 77.4% (106/137). The seropositivity rate increased from 18.7% in children aged between 6 months and 1 year to 100% in people older than 20 years of age. The highest proportion of titers ≥1:512 was found in children aged from 1 to 2 years.

Conclusion

Our results suggest that hMPV infection is present in Croatia, with primary infection occurring in early childhood. This is the first study that indicates the circulation of hMPV in Croatia.Human metapneumovirus (hMPV) is a newly discovered respiratory virus assigned to the Paramyxoviridae family, Pneumovirinae subfamily, Metapneumovirus genus. It was first isolated in 2001 from nasopharyngeal aspirates obtained from young children in the Netherlands (1). Sequence analysis of several isolates identified two major genetic lineages (subtypes A and B) that can be further divided into subgroups A1, A2, B1, and B2 (2). HMPV causes acute respiratory tract infections in all age groups (3,4). In hospitalized young children, hMPV infection is commonly present as bronchiolitis with or without pneumonitis (5,6), whereas bronchitis, bronchospasm, and pneumonitis are most commonly seen in elderly patients (3). Since the initial report, hMPV has been studied all over the world and it has been reported on all continents (7). Seroprevalence surveys from the Netherlands (1), Japan (8), and Israel (9) indicated that virtually all children are infected by 5-10 years of age. The aim of this study was to demonstrate the presence of hMPV infection in Croatia, by examining sera from Croatian people for specific anti-hMPV antibodies by an indirect immunofluorescent assay (IFA).     

Analysis of replication kinetics of the human metapneumovirus in different cell lines by real-time PCR

Human metapneumovirus (hMPV) is associated with acute respiratory tract disease especially in young children. Using a quantitative real-time TaqMan PCR, we analyzed the replication kinetics of hMPV in different cell lines. Our results indicate that hMPV replicates slightly more efficiently in LLC-MK2 than in Vero cells and poorly in HEp-2 cells.     

Detection of inter-spread repeat sequence in genomic DNA sequence

Various types of periodic patterns in nucleotide sequences are known to be very abundant in a genomic DNA sequence, and to play important biological roles such as gene expression, genome structural stabilization, and recombination. We present a new method, named "STEPSTONE", to find a specific periodic pattern of repeat sequence, inter-spread repeat, in which the tandem repeats of the conserved and the not-conserved regions appear periodically. In our method, at first, the data on periods of short repeat sequences found in a target sequence are stored as a hash data, and then are selected by application of an auto-correlation test in time series analysis. Among the statistically selected sequences, the inter-spread repeats are obtained by usual alignment procedures through two steps. To test the performance of our method, we examined the inter-spread repeats in Mycobacterium tuberculosis and Zamia paucijuga genomic sequences. As a result, our method exactly detected the repeats in the two sequences, being useful for identifying systematically the inter-spread repeats in DNA sequence.