[show abstract][hide abstract] ABSTRACT: In this study, the complete genomic sequence of a novel reassortant H9N2 avian influenza virus (AIV) from domestic ducks in eastern China was reported. Phylogenetic analysis showed that seven of the eight genes were all highly homologous to the chicken-origin H9N2 viruses, whereas the PB2 gene was homologous to the human-origin H1N1 virus, which suggested that domestic ducks might play a key role in the genetic reassortment and evolution of H9N2 AIVs in eastern China.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: The goose is usually considered to be resistant even to strains of Newcastle disease virus (NDV) that are markedly virulent for chickens. However, ND outbreaks have been frequently reported in goose flocks in China since the late 1990s with the concurrent emergence of genotype VIId NDV in chickens. Although the NDVs isolated from both chickens and geese in the past 15 years have been predominantly VIId viruses, published data comparing goose- and chicken-originated ND viruses are scarce and controversial. RESULTS: In this paper, we compared genotype VIId NDVs originated from geese and chickens genetically and pathologically. Ten entire genomic sequences and 329 complete coding sequences of individual genes from genotype VIId NDVs of both goose- and chicken-origin were analyzed. We then randomly selected two goose-originated and two chicken-originated VIId NDVs and compared their pathobiology in both geese and chickens in vivo and in vitro with genotype IV virus Herts/33 as a reference. The results showed that all the VIId NDVs either from geese or from chickens shared high sequence homology and characteristic amino acid substitutions and clustered together in phylogenetic trees. In addition, geese and chickens infected by goose or chicken VIId viruses manifested very similar pathological features distinct from those of birds infected with Herts/33. CONCLUSIONS: There is no genetic or phenotypic difference between genotype VIId NDVs originated from geese and chickens. Therefore, no species-preference exists for either goose or chicken viruses and more attention should be paid to the trans-species transmission of VIId NDVs between geese and chickens for the control and eradication of ND.
[show abstract][hide abstract] ABSTRACT: Simultaneous and sequential allantoic cavity inoculations of Specific-pathogen-free (SPF) chicken eggs with Influenza virus (AIV) and Newcastle disease virus (NDV) demonstrated that the interaction of AIV and NDV during co-infection was variable. Our research revisited the replication interference potential of AIV and NDV using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) for AIV and NDV to specifically detect the viral genomes in mixed infections.
Data from this survey showed that when different doses of NDV (Lasota or F48E8) and AIV (F98 or H5N1) were simultaneously inoculated into embryonating chicken eggs (ECE), interference with the growth of NDV occurred, while interference with the growth of AIV did not occur. When equal amount of the two viruses were sequentially employed, the degree of interference was dependent upon the time of superinfection and the virulence of virus.
AIV have a negative impact on NDV growth if they are inoculated simultaneously or sequentially and that the degree of interference depended upon the quantity and relative virulence of the virus strains used; however, interference with AIV was not observed. Only if NDV were inoculated at an earlier time will NDV able to interfere with the growth of AIV.
[show abstract][hide abstract] ABSTRACT: N-linked glycans are composed of three major types: high-mannose (Man), hybrid or complex. The functional role of hybrid- and complex-type N-glycans in Newcastle disease virus (NDV) infection and fusion was examined in N-acetylglucosaminyltransferase I (GnT I)-deficient Lec1 cells, a mutant Chinese hamster ovary (CHO) cell incapable of synthesizing hybrid- and complex-type N-glycans. We used recombinant NDV expressing green fluorescence protein or red fluorescence protein to monitor NDV infection, syncytium formation and viral yield. Flow cytometry showed that CHO-K1 and Lec1 cells had essentially the same degree of NDV infection. In contrast, Lec2 cells were found to be resistant to NDV infection. Compared with CHO-K1 cells, Lec1 cells were shown to more sensitive to fusion induced by NDV. Viral attachment was found to be comparable in both lines. We found that there were no significant differences in the yield of progeny virus produced by both CHO-K1 and Lec1 cells. Quantitative analysis revealed that NDV infection and fusion in Lec1 cells were also inhibited by treatment with sialidase. Pretreatment of Lec1 cells with Galanthus nivalis agglutinin specific for terminal α1-3-linked Man prior to inoculation with NDV rendered Lec1 cells less sensitive to cell-to-cell fusion compared with mock-treated Lec1 cells. Treatment of CHO-K1 and Lec1 cells with tunicamycin, an inhibitor of N-glycosylation, significantly blocked fusion and infection. In conclusion, our results suggest that hybrid- and complex-type N-glycans are not required for NDV infection and fusion. We propose that high-Man-type N-glycans could play an important role in the cell-to-cell fusion induced by NDV.
[show abstract][hide abstract] ABSTRACT: In spring 2009, one strain of H5N1 clade 2.3.2 virus was isolated from wild swans in Shanghai, indicating the importance of the wild swan in the ecology of this highly pathogenic avian influenza virus (HPAIV) in Eastern China. Pathogenicity experiments conducted in this study indicated that the virus was highly pathogenic for chickens but lowly pathogenic for mammalian hosts, as evidenced by reduced infection of mice. The analysis of complete genome sequences and genetic evolution showed that A/Swan/Shanghai/10/09 (SW/SH/09) may be derived from the strain A/silky chicken/Shantou/475/2004 (CK/ST/04), which is homologous to the influenza viruses isolated from chicken, duck, pika, little egret, swan, mandarin duck and bar-headed goose in China Hunan, China Qinghai, Mongolia, Russia, Japan, Korea, Laos and Hong Kong during 2007-2011, indicating that the virus has retro-infected diverse wild birds from chicken, and significant spread of the virus is still ongoing through overlapping migratory flyways. On the basis of the molecular analysis, we also found that there was a deletion of the glycosylation site (NSS) in amino acid 156 of the hemagglutinin (HA) protein when compared with that of the other Clade 2.3.2 viruses isolated between 2007 and 2011. More importantly, the sequence analysis of SW/SH/09 virus displayed the drug-resistant mutations on the matrix protein (M2) and neuraminidase (NA) genes.
[show abstract][hide abstract] ABSTRACT: Six nucleotide (nt) insertion in the 5'-noncoding region (NCR) of the nucleoprotein (NP) gene of Newcaslte disease virus (NDV) is considered to be a genetic marker for recent genotypes of NDV, which emerged after 1960. However, F48-like NDVs from China, identified a 6-nt insert in the NP gene, have been previously classified into genotype III or genotype IX.
In order to clarify their phylogenetic position and explore the origin of NDVs with the 6-nt insert and its significance in NDV evolution, we determined the entire genome sequences of five F48-like viruses isolated in China between 1946 and 2002 by RT-PCR amplification of overlapping fragments of full-length genome and rapid amplification of cDNA ends. All the five NDV isolates shared the same genome size of 15,192-nt with the recent genotype V-VIII viruses whereas they had the highest homology with early genotype III and IV isolates.
The unique characteristic of the genome size and phylogenetic position of F48-like viruses warrants placing them in a separate geno-group, genotype IX. Results in this study also suggest that genotype IX viruses most likely originate from a genotype III virus by insertion of a 6-nt motif in the 5'-NCR of the NP gene which had occurred as early as in 1940 s, and might be the common origin of genotype V-VIII viruses.
[show abstract][hide abstract] ABSTRACT: The purpose of this research is to establish a simple rapid amplification of cDNA ends (RACE) strategy for direct mapping of the 3' end and 5' end of the genomic RNA of Newcastle disease virus (NDV), and to analyze the leader and trailer sequence of NDV strains belonging to different genotypes.
Classic RNA Ligase Mediated Rapid Amplification of cDNA Ends (RLM-RACE) was specifically modified for mapping both ends of the NDV genome. 3'-RACE was carried out by genomic RNA ligation with 5' end phosphated adaptor CL+, and the 5' end was obtained by first strand cDNA with adaptor CL+.
A modified RLM-RACE strategy was established in this paper, which proved simple, low-cost, repetitive and could be specifically used to map genome ends of NDV. By using this method, the leader and trailer sequence of 5 NDV strains, termed JS/5/05/Go, JS/07/04/Pi, JS/07/16/Pi, JS/7/05/Ch and JS/9/05/Go, belonging to genotype III, VI and VII was determined, respectively.
The initial 8nt at the 3' and 5' ends of the genome of genotype I-VI NDV strains were complementary, whereas, the complementary sequences of strain JS/5/05/Go were up to 9 nt due to a mutation from T to C at the 9th nt in the 5' end. The 3' end of NDV genomic and anti-genomic RNA was predicted to form a potential hairpin structure. The U-->C(T-->C) mutation was located in the circle part of the hairpin in the 5' end of anti-genomic RNA, and had no visible influence on the formation of RNA secondary structure. However, the sequence of the circle part of the hairpin was changed from 3'-UUUC-5' to 3'-UCUC-5', more similar to the 3'-UCUUA-5' in the hairpin of genomic RNA.
[show abstract][hide abstract] ABSTRACT: The purpose of this research is trying to uncover the homology between two velogenic genotype III Newcastle disease virus (NDV) isolates with NDV strain Mukteswar, which was commonly used as vaccine in China.
The full-length genome of NDV isolates, JS/7/05/Ch and JS/9/05/Go, were determined by RT-PCR and then analyzed.
The full-length genome of 2 genotype III velogenic NDV isolates shared 99.7% nucleotide identity with that of Mukteswar. The results of alignment of 6 viral genes showed that JS/7/05/Ch and JS/9/05/Go shared nucleotide and amino acid identities of 99.6% - 99.9% and 98.8% - 99.8% with that of Mukteswar, respectively. Furthermore, the IVPI score of JS/7/ 05/Ch and JS/9/05/Go was 2.18 and 1.33, remarkablely higher than that of Mukteswar, while the 3 NDV strains shared the consensus cleavage site of virulent NDV strains (112RRQRRF117). Virulence of NDV is mainly determined by the amino acid sequence of the fusion (F) protein cleavage site, since host proteases that cleave the F protein of virulent strains are present in more tissues than those that cleave the F protein of lentogenic strains. However, 3 NDV strains with same F protein cleavage site showed different virulence. The entire genomic sequence of JS/7/05/Ch, JS/9/05/Go and Mukteswar was further analyzed. Three strains shared some gene-start signal, gene-end signal, intergenic region and six highly identical viral genes. Most amino acid differences among JS/7/05/Ch, JS/9/05/Go and Mukteswar were found in the predicted HN and L protein, and the predicted NP, P, V, W, M and even F protein had few amino acid differences.
First, it is concluded that field isolates JS/7/05/ Ch and JS/9/05/Go are derived from Mukteswar and more attention must be paid to the virulence enhancement of vaccine strains. Second, it is proposed that the differences in the amino acid sequence of HN and L protein may give rise to the significant virulence differences between two NDV isolates and Mukteswar.