Previously, we demonstrated the presence of a second copy of LPS myristoyl transferase in enterohemorrhagic Escherichia coli O157:H7, an important zoonotic diarrheagenic food-borne pathogen; the pO157-encoded ecf (an eae-conserved fragment) and the chromosomally-encoded lpxM (also referred to as msbM) genes. Although both genes share the same function as an LPS myristoyl transferase, the pO157-encoded ecf is thermoregulated via an intrinsically curved DNA while the chromosomal lpxM is regulated by the PhoP/Q two component regulatory system. However, it is unclear why E. coli O157: H7 carries two copies of LPS myristoyl transferase that are differentially regulated. In this study, a whole genome-scale transcriptome specific to E. coli O157:H7 was carried out for identification of the genes differentially expressed in the amyristoylated E. coli O157:H7. The results identified a total of 110 EHEC genes that were up- or down-regulated in the amyristoylated E. coli O157:H7 strain, including genes associated with virulence (26.36%), metabolism (20.91%), transport (10.91%), signal transduction (4.55%), genetic information processing (3.64%), stress response (2.73%), regulatory function (2.73%), motility/adherence (3.64%), cell envelope (2.73%), cell division (1.82%) and ORFs of unknown function (17.27%). Of particular interest, the expression of LEE pathogenicity island genes was significantly influenced by LPS structural defects.
Foot-and-mouth disease (FMD) has great potential for causing huge economic loss and was the first disease identified by the World Organisation for Animal Health (OIE) in its official list of free countries and zones. This study examined the governmental expenditures for five FMD epidemics that occurred in the Republic of Korea between 2000 and 2011. The costs of an epidemic ranged from 26 billion Korean won (KRW, approximately 23.6 million US dollars, ) to a maximum of 2,044 billion KRW (US 1.9 billion). For two epidemics in which vaccinations were implemented, the costs were higher than those epidemics without vaccination. The mean cost for an outbreak ranged from 0.5 billion KRW (US 4.5 million) for the 2010/2011 epidemic to 18.2 billion KRW (US 16.5 million) for the 2000 epidemic. Mean costs per infected premises were 7.0 billion KRW for cattle farms (95% CI: 4.72∼9.28), 1.38 billion KRW for pig farms (0.88∼1.87), 0.11 billion KRW for deer farms (0.08∼0.14), and 0.10 billion KRW for goat farms (0.07∼0.13). The highest cost for an outbreak in cattle seemed associated with the number of outbreak cattle farms in two epidemics in which vaccination was implemented.
Matrix 2 protein ectodomain (M2e) of influenza virus appears to be a promising vaccine candidate because its sequence is highly conserved among virus strains. However, M2e is too meager to induce a strong immune response by itself. Several approaches are being used to increase the antigenicity of M2e. In an effort to enhance the M2e-specific immune response, we generated a TAT-conjugated M2e recombinant protein. Seven-week-old BALB/c mice were divided into three groups and transcutaneously immunized with 100 μg TAT-8×M2e (TAT conjugated with eight copies of M2e) and 8×M2e (eight copies of M2e) proteins on days 1, 15 and 29. The control mice were injected with PBS on the same days. Antibody titers specific for M2e were measured using indirect ELISA. Mice immunized with the TAT-8×M2e and 8×M2e proteins developed almost the same levels of M2e-specific total IgG and IgG1 antibodies. However, a higher level of M2e-specific IgG2a was observed in mice immunized with TAT-8×M2e than in those immunized with 8×M2e. These results suggest that TAT has an adjuvant effect that induces a Th1-type immune response. Therefore, the TAT-M2e vaccine can be applied to animals as a new influenza vaccine for enhancement of Th1-type immune responses.
We previously developed a novel attenuated Salmonella Typhimurium (S.Typhimurium) △lon△cpxR vaccine. This study was conducted in order to examine whether this vaccine could effectively protect growing piglets against Salmonella infection. Pregnant sows in group A were primed and boosted with the vaccine, whereas pregnant sows in group B received sterile PBS-sucrose. After farrowing, newborn piglets in groups A and B were challenged with a wild type virulent S. Typhimurium at three weeks of age. During the study, serum IgG titers of piglets in group A were significantly higher than those of piglets in group B (P<0.001). In addition, clinical signs were observed in 5.9% of piglets in group A during the entire experimental period after the challenge, while diarrhea was observed in 81.6% of piglets in group B. These results indicate that vaccination of the pregnant sows resulted in effective protection in piglets against Salmonella infection.
Rotaviruses are double-stranded RNA viruses of the family Reoviridae, a highly diverse family of pathogens of humans and animals. In this study, we identified the lapine rotavirus from diarrheic feces of rabbits by polymerase chain reaction. In order to determine the genetic characteristics of the Korean strain, the sequences of the VP4, VP7, and NSP4 genes were determined and compared with those of reference sequences. Results of sequence and phylogenetic analyses showed that our strain was a G3P  rotavirus carrying the group C gene encoding NSP 4 proteins. This is the first report of an outbreak and molecular characterization of lapine rotavirus in Korea.
Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and nonprofessional phagocytes and cause abortion in domestic animals and undulant fever in humans. Brucella species can survive in a variety of cells, including macrophages and their virulence and chronic infections are thought to be due to their ability to avoid the killing mechanisms within macrophages. Inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival of Brucella in professional and nonprofessional phagocytes. Toll-like receptors (TLRs) are part of a skillful system for detection of invasion by microbial pathogens. Recognition of microbial components by TLRs triggers signaling pathways that promote expression of genes and regulate innate immune responses. Recent studies for the interaction between TLRs-Brucella have indicated the importance of control of Brucella infection. Here, we review selected aspects of TLRs-Brucella interaction, which may be helpful to understanding the mechanism of Brucella pathogenesis.