Salmonella species is one of the major bacterial agents that causes gastrointestinal disease in pigs. Natural antimicrobials derived from plants may be alternative therapeutics that could replace currently used antibiotics in the control of infectious disease. In this study, we assessed the antibacterial activity of Oenothera biennis L. extract against Salmonella Typhimurium both in vitro and in vivo. O. biennis L. extract had a strong inhibitory effect on S. Typhimurium in vitro, reducing bacterial growth by 87%. For the in vivo experiment, 16 post-weaned pigs were divided into 4 groups consisting of 4 pigs each: an uninfected, untreated negative control group; an untreated positive control group that was infected with S. Typhimurium; and two groups that were infected with S. Typhimurium and treated with either 0.1% or 0.5% O. biennis L. extract. Pigs were followed for 21 days after infection, and their body weight, daily gains, feed conversion ratio (FCR), and feed efficiency (FE) were monitored. The pigs treated with O. biennis L. extract had significantly higher daily gains than the positive control group (p<0.05). The O. biennis L. extract-treated pigs also exhibited better weight gain and FE, as well as a lower FCR and less severe diarrhea, than the positive controls but these results were not statistically significant. Our study demonstrates that O. biennis L. extract has antibacterial effects against S. Typhimurium, both in vitro and in vivo, and that these antibacterial effects may produce better growth performance in pigs infected with S. Typhimurium.
Pathologic chronic inflammation, such as that seen with microbial infection and autoimmune diseases, creates microenvironmental conditions that promote cancer. Therefore, if chronic inflammation can be alleviated, the risk of carcinoge- nesis may decrease. Turmeric is a dried rhizome powder from Curcuma longa. Curcumin, the major constituent of turmeric, presents anti-inflammatory, antioxidant, antimicrobial and chemopreventive activities. In the present study, we investigated immune responses to dietary turmeric in ICR mice to determine the effects of turmeric when used as a dietary chemoprevention agent. After dietary turmeric was given for three or six weeks to ICR male mice, the immune responses were characterized. The methods of characterization involved; the determination of the T cell subpopulation in the spleen, relative mRNA expression levels of IFN-γ and TNF-α and serum lysozyme activity. Dietary turmeric was found to decrease spleen weight, decrease the proportion of CD4-CD8+ T cells, and decrease phagocytic activity. These results suggest that turmeric might alleviate abnormal chronic inflammation by the action of immune suppression.
A cell line of bovine origin was immortalized to isolate foot-and-mouth disease virus (FMDV). The immortalization was performed by infection of bovine primary epithelial cells with a recombinant retrovirus that overexpressed the human telomerase (hTERT), after primary culture of fetal bovine kidney tissue and removal of fibroblasts. After cloning the immor- talized cell line into single cells, the cloned cell lines were named JNUBK-1, JNUBK-2, JNUBK-3 and JNUBK-4, according to their characteristics. To confirm the epithelial phenotype of the cell lines JNUBK-3 and JNUBK-4, which showed stable proliferation capability over 35 generations after immortalization, the expression of cytokeratin and fibronectin was measured. Finally, the FMDV titer in the JNUBK-3 and JNUBK-4 cell lines was measured and was 800∼2,000 times higher than that of the currently used cell line IRBS-2. In conclusion, more sensitive isolation and production of FMDV became possible through the use of the immortalized JNUBK-3 and JNUBK-4 cell lines.
Brucellosis is a zoonotic infectious disease of domestic animals, wild animals and humans. Innate immunity is a rapid and non-specific immune response that occurs during the early stages of Brucella invasion. Physical barriers such as epithelial cells and gastric juice secretions form the first line of defense. Humoral components such as complement and lysozyme can remove microorganisms by opsonization and bactericidal actions. Cellular components of the immune system, including macrophages, dendritic cells, neutrophils and innate T cells, have major roles in innate immunity. They recognize invading Brucella spp. by various cell surface receptors and then kill both the invading microorganisms and infected cells owing to their phagocytic or cytotoxic activity. In addition, they present Brucella antigens or produce cytokines to trigger adaptive immunity. Activated adaptive immunity consists of T helper cells, cytotoxic T cells and antigen-specific antibody-producing B cells. These can eliminate Brucella spp. effectively via antigen-specific mechanisms and by immunological memory. T cells activate bactericidal functions in macrophages by producing cytokines such as IFN-γ and by exerting cytotoxic effects on the infected cells. B cells produce antigen-specific antibodies that neutralize or opsonize the antigen. Because Brucella spp. can survive in macrophages and other host cells, Th-1 cellular immunity that enhances the bactericidal effects of phagocytic cells and the cytotoxic effects of lymphocytes is more important than humoral immunity in Brucella infection.