Figure 1.
Geographical location of poultry farms from which six virus isolates were obtained.
Table 1.
Summary of clinical viral isolates.
Figure 2.
Modeled structure and domain architecture of envelope protein of FX-2012 strain.
A) Cartoon scheme view of envelope protein structure. Sites containing amino acid changes were colored red and all these changes were listed in gray boxes. The side-chains of glycosylated residues were colored cyan. For illustration purpose, a β-D-Manp-(1-4)-β-D-GlcpNAc (colored magenta) was added to the glycosylation sites. B). Domain diagram of envelope protein. Domain boundaries were labeled (black) on top of the diagram. The two glycosylation sites were labeled magenta. Domain boundaries were predicted based on domain architecture of Japanese encephalitis virus. Domain colors: orange, domain I; green, domain II; blue, domain III.
Figure 3.
Multiple sequence alignment of the E proteins.
The predicted glycosylation sites were marked with star underneath the alignment. Conserved histidines at E protein oligomerization interfaces were labeled with blue circle while histidines conserved in DTMUV and JEV viruses were labeled with magenta circle. The diagram of secondary structure was determined according to the modeled structure of E protein of FX-2012 strain and shown underneath the sequence alignment (rectangle, helix; arrow, β strand). Transmembrane helixes were predicted with TMHMM. Color scheme for sequence alignment position: positive charged amino acids: red; negative charged amino acids, magenta; polar amino acids, green; hydrophobic amino acids, blue. Less conserved positions were colored with lighter color of the corresponding amino acid category. Color scheme for secondary structure: orange, domain I; green, domain II; blue, domain III; red, transmembrane helix.
Figure 4.
Serum neutralization properties of six DTMUV isolates.
Antisera generated from ducks inoculated with BZ-10 and FX-12, respectively, were selected to test the effects of E protein mutations on neutralization sensitivity of each of six viruses as described in Materials and Methods. Each experiment was run in duplicate and repeated twice. The serum neutralizing titers were determined by the minimal serum dilution that inhibited chicken embryo death. The titers were the mean values of two independent experiments.
Table 2.
Prevalence of the observed polymorphic residues in the E protein between Tembusu and Sitiawan viruses in DTMUVa.
Figure 5.
Bayesian phylogenetic tree of viral E proteins.
The six strains of DTMUV we sequenced were marked with purple background. The Bayesian posterior probabilities were labeled on each node (1, high confident branching; 0, low confident branching). The bottom scale bar represents divergence time (unit: year).