Search

The control of swine influenza virus (SIV) infection is paramount for increasing the productivity of pig farming and minimizing the threat of pandemic outbreaks. Thus, SIV surveillance should be conducted by region and on a regular basis. Here, we established a microneutralization assay specific for SIV seroprevalence surveillance by using reporter gene-expressing recombinant influenza viruses. Growth-based SIV seroprevalence revealed that most sows and piglets were positive for neutralizing antibodies against influenza viruses. In contrast, the 90-day-old growing pigs exhibited limited neutralizing activity in their sera, suggesting that this particular age of population is most susceptible to SIV infection and thus is an ideal age group for SIV isolation. From nasal swab specimens of healthy pigs in this age population, we were able to isolate SIVs at a higher incidence (5.3%) than those of previous reports. Nucleotide sequencing and phylogenetic analysis of the hemagglutinin (HA) genes revealed that the isolated SIVs have circulated and evolved in pigs but not have been recently introduced from humans, implying that a large number of SIV lineages may remain "undiscovered" in the global porcine populations. We propose that the 90-day-old growing pig-targeted nasal swab collection presented in this study facilitates global SIV surveillance and contributes to the detection and control of SIV infection., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Polyethylene glycol dehydrogenase (PEGDH) from Sphingopyxis terrae (formerly Sphingomonas terrae) is composed of 535 amino acid residues and one flavin adenine dinucleotide per monomer protein in a homodimeric structure. Its amino acid sequence shows 28.5 to 30.5% identity with glucose oxidases from Aspergillus niger and Penicillium amagasakiense. The ADP-binding site and the signature 1 and 2 consensus sequences of glucose-methanol-choline oxidoreductases are present in PEGDH. Based on three-dimensional molecular modeling and kinetic characterization of wild-type PEGDH and mutant PEGDHs constructed by site-directed mutagenesis, residues potentially involved in catalysis and substrate binding were found in the vicinity of the flavin ring. The catalytically important active sites were assigned to His-467 and Asn-511. One disulfide bridge between Cys-379 and Cys-382 existed in PEGDH and seemed to play roles in both substrate binding and electron mediation. The Cys-297 mutant showed decreased activity, suggesting the residue's importance in both substrate binding and electron mediation, as well as Cys-379 and Cys-382. PEGDH also contains a motif of a ubiquinone-binding site, and coenzyme Q10 was utilized as an electron acceptor. Thus, we propose several important amino acid residues involved in the electron transfer pathway from the substrate to ubiquinone.

The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.