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Lu X.,China Agricultural University | Lu X.,National Institute for Communications Disease Control and Prevention | Gong Y.F.,China Agricultural University | Gong Y.F.,Hebei Normal University of Science and Technology | And 3 more authors.
Genetics and Molecular Research | Year: 2014

Increased disease resistance through improved general immune capacity would be beneficial for the welfare and productivity of farm animals. Classical swine fever (CSF) is a contagious disease in farm animals. The immunoglobulin G (IgG) blocking percentage of CSF virus (CSFV) in serum is an essential diagnostic parameter in veterinary practice. In addition, lysozymes are a part of the innate immune system. To identify quantitative trait loci (QTL) for IgG blocking percentage of CSFV and lysozyme concentration, IgG blocking percentage and lysozyme concentration in serum were measured in a composite pig population before and after challenge with modified live CSF vaccine. Through genome-wide mapping by MQREML analysis and the SOLAR software, several QTL for the lysozyme concentration and the IgG blocking percentage of CSFV were identified, respectively. Within these QTL regions, some known genes were revealed, and some of them may serve as candidate genes in the pig. © FUNPEC-RP. Source

Liu Z.,National Institute for Communications Disease Control and Prevention | Liu Z.,Huaihua Medical College | Zheng H.,National Institute for Communications Disease Control and Prevention | Gottschalk M.,University of Montreal | And 5 more authors.
PLoS ONE | Year: 2013

Streptococcus suis is an important zoonotic agent causing severe diseases in pigs and humans. To date, 33 serotypes of S. suis have been identified based on antigenic differences in the capsular polysaccharide. The capsular polysaccharide synthesis (cps) locus encodes proteins/enzymes that are responsible for capsular production and variation in the capsule structures are the basis of S. suis serotyping. Multiplex and/or simplex PCR assays have been developed for 15 serotypes based on serotype-specific genes in the cps gene cluster. In this study, we developed a set of multiplex PCR (mPCR) assays to identify the 33 currently known S. suis serotypes. To identify serotype-specific genes for mPCR, the entire genomes of reference strains for the 33 serotypes were sequenced using whole genome high-throughput sequencing, and the cps gene clusters from these strains were identified and compared. We developed a set of 4 mPCR assays based on the polysaccharide polymerase gene wzy, one of the serotype-specific genes. The assays can identify all serotypes except for two pairs of serotypes: 1 and 14, and 2 and 1/2, which have no serotype-specific genes between them. The first assay identifies 12 serotypes (serotypes 1 to 10, 1/2, and 14) that are the most frequently isolated from diseased pigs and patients; the second identifies 10 serotypes (serotypes 11 to 21 except 14); the third identifies the remaining 11 serotypes (serotypes 22 to 31, and 33); and the fourth identifies a new cps cluster of S. suis discovered in this study in 16 isolates that agglutinated with antisera for serotypes 29 and 21. The multiplex PCR assays developed in this study provide a rapid and specific method for molecular serotyping of S. suis. © 2013 Liu et al. Source

Wang Q.,National Institute for Communications Disease Control and Prevention | Kan B.,National Institute for Communications Disease Control and Prevention | Wang R.,National Institute for Communications Disease Control and Prevention
PLoS ONE | Year: 2013

Filamentous phages have distinguished roles in conferring many pathogenicity and survival related features to Gram-negative bacteria including the medically important Vibrio cholerae, which carries factors such as cholera toxin on phages. A novel filamentous phage, designated VFJΦ, was isolated in this study from an ampicillin and kanamycin-resistant O139 serogroup V. cholerae strain ICDC-4470. The genome of VFJΦ is 8555 nucleotides long, including 12 predicted open reading frames (ORFs), which are organized in a modular structure. VFJΦ was found to be a mosaic of two groups of V. cholerae phages. A large part of the genome is highly similar to that of the fs2 phage, and the remaining 700 bp is homologous to VEJ and VCYΦ. This 700 bp region gave VFJΦ several characteristics that are not found in fs2 and other filamentous phages. In its native host ICDC-4470 and newly-infected strain N16961, VFJΦ was found to exist as a plasmid but did not integrate into the host chromosome. It showed a relatively wide host range but did not infect the classical biotype O1 V. cholerae strains. After infection, the host strains exhibited obvious inhibition of both growth and flagellum formation and had acquired a low level of ampicillin resistance and a high level of kanamycin resistance. The antibiotic resistances were not directly conferred to the hosts by phage-encoded genes and were not related to penicillinase. The discovery of VFJΦ updates our understanding of filamentous phages as well as the evolution and classification of V. cholerae filamentous phage, and the study provides new information on the interaction between phages and their host bacteria. © 2013 Wang et al. Source

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