Innate immunity and protective effects of orally administered betaine against viral and bacterial diseases in the olive flounder Paralichthys olivaceus (Temminck & Schlegel).

Sustainable methods that increase farmed fish yield while controlling infections are required to prevent economic losses in aquaculture farms. In this study, we evaluated the effects of betaine-supplemented (0%, 0.1%, 0.5%, and 1.0%) feed on the growth and immunity of the olive flounder Paralichthys olivaceus. Feed conversion ratios, post-infection cumulative mortality rates and innate immune responses were monitored. Weight gain was significantly higher with 0.5% and 1.0% than with 0% and 0.1% betaine-supplemented feed. Lysozyme activity was highest with 1.0% betaine. Respiratory burst activity was highest with 0.5% and 1.0% betaine. Serum bactericidal activity against Edwardsiella tarda was highest with 1.0% betaine (40% increase in survival rates compared with those in the control). Furthermore, serum virucidal activity against the viral haemorrhagic septicaemia virus (VHSV) was higher with 1.0% betaine than with other concentrations. With 0.5% and 1.0% betaine, the survival rates against VHSV were higher than those in the control until day 11, after which they declined. Our study suggests that betaine is a promising agent for promoting the growth of and enhancing immunity against E. tarda in olive flounders. Our findings may further contribute to developing necessary alternatives to conventional antibiotics in fish farming.

Intranasal Vaccination with OuterMembrane Protein of Orientia tsutsugamushi induces Protective Immunity Against Scrub Typhus

Scrub typhus develops after the individual is bitten by a trombiculid mite infected with Orientia tsutsugamushi. Since it has been reported that pneumonia is frequently observed in patients with scrub typhus, we investigated whether intranasal (i.n.) vaccination with the outer membrane protein of O. tsutsugamushi (OMPOT) would induce a protective immunity against O. tsutsugamushi infection. It was particular interest that when mice were infected with O. tsutsugamushi, the bacteria disseminated into the lungs, causing pneumonia. The i.n. vaccination with OMPOT induced IgG responses in serum and bronchoalveolar lavage (BAL) fluid. The anti-O. tsutsugamushi IgA Abs in BAL fluid after the vaccination showed a high correlation of the protection against O. tsutsugamushi. The vaccination induced strong Ag-specific Th1 and Th17 responses in the both spleen and lungs. In conclusion, the current study demonstrated that i.n. vaccination with OMPOT elicited protective immunity against scrub typhus in mouse with O. tsutsugamushi infection causing subsequent pneumonia.

Annual Fluctuation in Chigger Mite Populations and Orientia Tsutsugamushi Infections in Scrub Typhus Endemic Regions of South Korea

OBJECTIVES: Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and Orientia tsutsugamushi infections in South Korea.METHODS: During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of Orientia tsutsugamushi.RESULTS: During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included Leptotrombidium pallidum (43.5%), L. orientale (18.9%), L. scutellare (18.1%), L. palpale (10.6%), and L. zetum (3.6%). L. scutellare and L. palpale populations, were relatively higher in Autumn. Monthly O. tsutsugamushi infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn.CONCLUSION: The findings demonstrated a bimodal pattern of the incidence of O. tsutsugamushi infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.

Serologic Survey and Risk Factors for Coxiella burnetii Infection among Dairy Cattle Farmers in Korea

BACKGROUND: The zoonotic disease Q fever is caused by Coxiella burnetii and usually affects high-risk human populations. We conducted a serological survey of dairy cattle farmers in Korea to determine seroreactivity and identify risk factors for C. burnetii infection. METHODS: This cross-sectional study included 1,824 of 7,219 dairy cattle farms (25.3%) in the study region. The selected dairy cattle farmers visited the nearest public health centers or branches with completed questionnaires. Serum samples from the farmers were tested using an indirect immunofluorescence assay to detect phase II C. burnetii immunoglobulin (Ig) G or M antibodies. RESULTS: A total of 1,222 dairy cattle farmers from 784 dairy cattle farms (43.0%) participated in this study, and 11.0% (134/1,222) exhibited seroreactivity, defined as a phase II antigen IgG or IgM titer ≥ 1:16. In the multivariate analysis, male sex, residence in Gyeonggi Province, a larger herd size, and ocular/oral contact with birth products during calf delivery were significantly associated with a higher risk of C. burnetii infection. Furthermore, the risk was significantly lower among farmers who always wore protective gloves while cleaning cattle excretion, compared to those who sometimes or rarely wore protective gloves. CONCLUSION: Dairy cattle farmers should exercise caution by avoiding ocular/oral contact with birth products during calf delivery and by using protective equipment (including gloves).

Seroreactivity to Q Fever Among Slaughterhouse Workers in South Korea / 예방의학회지

OBJECTIVES: Q fever is a zoonotic disease that occurs worldwide; however, little is known about its prevalence in South Korea. We attempted to determine the prevalence of Q fever seroreactivity among Korean slaughterhouse workers and the risk factors for seroreactivity according to the type of work. METHODS: The study was conducted among 1503 workers at a total of 73 slaughterhouses and 62 residual-product disposal plants. During the study period, sites were visited and surveys were administered to employees involved in slaughterhouse work, and serological tests were performed on blood samples by indirect immunofluorescence assays. Serological samples were grouped by job classification into those of slaughter workers, residual-product handlers, inspectors and inspection assistants, and grading testers and testing assistants. Employee risk factors were analyzed according to the type of work. RESULTS: Out of 1481 study subjects who provided a blood sample, 151 (10.2%) showed reactive antibodies. When these results were analyzed in accordance with the type of work, the result of slaughter workers (11.3%) was similar to the result of residual-product handlers (11.4%), and the result of inspectors and assistants (5.3%) was similar to the result of grading testers and assistants (5.4%). Among those who answered in the affirmative to the survey question, “Has there been frequent contact between cattle blood and your mouth while working?” the proportions were 13.4 and 4.6%, respectively, and this was identified as a risk factor that significantly varied between job categories among slaughterhouse workers. CONCLUSIONS: This study found a Q fever seroreactivity rate of 10.2% for slaughterhouse workers, who are known to be a high-risk population. Contact with cattle blood around the mouth while working was the differential risk factor between job categories among slaughterhouse workers.

Effect of TBT and PAHs on CYP1A, AhR and Vitellogenin Gene Expression in the Japanese Eel, Anguilla japonica.

Gene expressions of cytochrome P4501A (CYP1A), aryl hydrocarbon receptor (AhR) and vitellogenin (Vg) by endocrine disruptors, benzo[α]pyrene (B[a]P) and tributyltin (TBT) were examined in cultured eel hepatocytes which were isolated from eels treated previously with B[a]P (10 mg/kg) or estradiol-17ß (20 mg/kg) in vivo, and the relationship between CYP1A, AhR and Vg genes were studied. When the cultured eel hepatocytes were treated with B[a]P (10(-6)-10(-5) M) the gene expressions of CYP1A and AhR were enhanced in a concentration-dependent manner. However, when treated with TBT (10(-9)-10(-5) M) the gene expressions of CYP1A and AhR were suppressed at high concentrations (10(-6)-10(-5) M), while having no effects at low concentrations (10(-9)-10(-7) M). Gene expression of Vg was also suppressed by TBT in a concentration-dependent manner in cultured eel hepatocytes which was previously treated in vivo with estradiol-17ß.

Androgen action on hepatic vitellogenin synthesis in the eel, Anguilla japonica is suppressed by an androgen receptor antagonist.

Involvement of additional hormones other than estrogen in the control of vitellogenin (Vg) synthesis has been suggested in fish. However, no satisfactory explanation on the mechanism of the action of these hormones has been reported. In this study, we have exploited the possibility of androgen receptor mediation during the androgen action on the pathway of Vg synthesis. Hepatocytes were prepared from sexually immature Japanese eel Anguilla japonica and treated with estradiol-17beta (E2), 17alpha-methyltestosterone (MT), growth hormone, tamoxifen or flutamide, or in combination of these. Spent culture media were analysed by SDS-PAGE for Vg detection. Results from the chemical treatments demonstrated the necessity of E2 as the primary factor for Vg synthesis and requirement of additional hormones for the full expression of Vg. The effects of E2 and MT were effectively blocked by tamoxifen, an estrogen receptor antagonist and flutamide, an androgen receptor antagonist, respectively, indicating ER-mediated estrogen action and AR-mediated androgen action on Vg synthesis in this species.

Characterization of lipopolysaccharide responsive proteins that binds to the 5'-flanking regions of mouse Rantes.

When macrophage (like the RAW264.7 cell line) was stimulated with lipopolysaccharide (LPS), factors that bind specifically to the LPS responsive element (LRE) of murine Rantes gene appeared in the nucleus. An electrophoretic mobility shift assay (EMSA) detected 2 specific bands, designated as S (slow) and M (middle). The S band appeared within 15 min of LPS stimulation, and reached its highest intensity within 2 h. The M band was present in unstimulated cells, but after stimulation its intensity increased and reached its highest intensity also in about 2 h. Significantly, in LPS hyporesponsive 10-9 macrophage like cells, the S band was absent. The M band was present in equal amounts in stimulated and unstimulated cells. The results suggest that the S band was induced by LPS stimulation. In the nuclear extract, the native molecular weight of the S band-forming factor was approximately 270 kDa, and that of the M bands-forming factor was approximately 140 kDa. U.V. cross linking studies consistently showed at least 2 different polypeptides of approximate molecular mass of 70 kDa, both in the S band-forming factor (complex) and the M band-forming factor (complex). In the nuclear extracts of both the LPS stimulated and unstimulated cells, we detected a factor with approximate molecular mass of 120 kDa that could convert the S band-forming complex to the M band-forming complex. This factor, designated as a converting factor, is a protein phosphatase since its activity was blocked by okadaic acid, an inhibitor of Ser/Thr protein phosphatase. Also, purified protein phosphatase type 1 (PP-1) could convert the S band-forming complex to the M band-forming complex.