• 한국동물위생학회지
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• 제19권2호
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• pp.139-153
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• 1996

Porcine E coli infection is a disease caused by Enterotoxin produced by Enterotoxigenic Escherichia coli(ETEC). Enteric colibacillosis has become an economically important disease in pigs as a result of increasing intensification of farrowing management. The present study undertaken to obtain the antibiotic sensitivity and distribution of serogroups and pili producibility test of ETEC from E. coli isolates in Chonnam. The results obtained were as follows. 1. A total of 71 isolates identified as E, coli employing IMViC system from rectal specimens of 54 piglets with diarrhea. 2. In antibiotic sensitivity test, isolates showed high sensitivity to AN, CM, Fox, GM, but resistance to EM, NA TC. 3. The distribution of 25 Isolates of serogroups were 0141:K85(11.3%), 08:K87(8.5%), 064:K (5.6%), 0138:K8l (4.2%), 0139 :K82(2.8%), 0157:K88ac(1.4%) and 0149:K9l (1.4%). 4. MRHA of guinea pig erythrocytes was detected in 8 out of 25OK serotypes and 9 out of 46 unidentified serotypes. MRHA titers of serotypes showed from 64 to 128 in 0141: K85, 2 in 0138:K8l and no titers in 0139:K82. 5. The production of heat labile enterotoxin of ETEC was detect 39 out of 52 isolates showed $\beta$-hemolysin, 7 out of 52 isolates showed ${\gamma}$-hemolysin and 6 out of 52 isolates showed ${\gamma}$-hemolysin by $GM_1$ganglioside ELISA. The distribution of LT toxin were in 12 isolate showed $\beta$-hemolysin, 2 isolates showed ${\alpha}$-hemolysin and 3 isolates showed ${\gamma}$-hemolysin in 25 OK serotypes.

• 한국동물위생학회지
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• 제19권2호
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• pp.126-138
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• 1996

Lungs from 109 slaughter pigs with gross lesions indicating enzootic Pneumonia of pigs(EPP) and 16 grossly normal lungs, all originating from seven different herds, were subjected to microbiological examinations. The microbiological studies were included both bacterial and mycoplasmal culture. From lungs of 125 slaughter pigs, 87.2% pigs were pneumonia lesions alone or complexly Mycoplasma spp., pasteurella multocidu(p. multocida), Streptococcus spp., and Actinobacillus pleuropneumoniue(A. pleuropneumoniae) were detected in 39.4%, 42.2%, 13.8%, and 3.7% of the pneumonic lungs, respectively. P. multocida was the most frequently isolated organism in pneumonic lungs. Mycoplasmas not isolated organism in 33.9% the pneumonic lungs even If [here are gross lessions mycoplasmas. The amounts of pneumonia in lungs with Mycoplasma spp. alone, a concurrence of Mycoplasma spp. and P. multocida, p. multocida alone, a concurrence of P. multocida and A. pleuropneumoniae, and a concurrence of Mycoplasma spp. and A pleurdpneumoniae were 10.1%, 22.7%, 18.7%, 25%, and 30%, respectively These findings indicated that p. multocida might be involved in the pathogenesis of pneumonia in slaughter pigs. Mycoplasma spp. was also, in this study, associated with higher frequency of pneumonia. The frequency of pigs snout lesion grade 0∼5 inclusive were 27.2%, 28%, 19.2%, 16%, 6.4%, and 3.2% from 125 slaughter pigs. 32(25.6%) pigs were positive and 13~30% in the pigs from seven herds were found to be infected with atrophic rhintis (AR). A total of 46 P. multocida strains In pneumonic lungs were further characterized by capsular serotyping and testing for production of dermonecrotic toxin. 42(91.3%) of strains were capsular A and 4(8.7%) were type D. Out of the type A and type D strains, 86% and 75% were toxigenic, respectively.

• 대한수의학회지
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• 제41권2호
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• pp.197-202
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• 2001

Although several methods have been developed and applied to control swine respiratory diseases, the disease induces severe economic impact to swine industry worldwide. As one of the new trials, application of egg yolk antibody(IgY) was attempted for the purposes and immune response in sera and egg yolk was analysed with ELISA in previous study. In this study, immunological specificity of the IgY was analysed by Western blot analysis. In the analysis of causative agents of atrophic rhinits, B bronchiseptica and P multocida 4D, proteins of 33, 40, 43, 67 and 141 kDa were specifically reacted with IgY Also, 40 and 110 kDa proteins were identified as the major immunogens in P multocida 3A. In A pleuropneumoniae serotypes 2 and 5, 40 kDa and 47 kDa proteins were found to be the major reactive ones. These results suggested that egg yolk antibodies from immunized hens was specific with antigens injected into hens and partially purified antigens, outer membrane proteins and dermonecrotic toxin, were more effective than bacterin for the production of specific antibody.

• 한국물환경학회지
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• 제33권5호
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• pp.538-545
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• 2017

The purpose of this study is to investigate growth response and toxigenicity under various temperature and nutritional conditions, in order to understand the physioecological characteristics of Aphanizomenon flos-aquae, which is a bloom-forming cyanobacterium in the Nakdong River. The strain was inoculated into media under combinations of four temperatures (4, 12, 21, $30^{\circ}C$) and three nutrients (modified CB medium, P-depleted CB medium, N-depleted CB medium) for 28 days. The algae-inhibition tests were performed to assess the potential allelopathic effects of the strains' filtrates on the growth of four algae strains (Microcystis aeruginosa, Aulacoseria ambigua f. spiralis, Aphanizomenon flos-aquae, Scenedesmus obliquus). Toxin production of a strain was measured by Enzyme-Linked ImmunoSolbent Assay (ELISA). The optimal growth temperature (Topt) of strains was $19.9^{\circ}C$ ($18.3-21.2^{\circ}C$), and the temperature range for growth was from $-0.3^{\circ}C$ to $34.3^{\circ}C$. Specific growth rate (${\mu}$) in modified CB medium varied from 0.10 to $0.16day^{-1}$, and the maximum growth rate (${\mu}_{max}$) was $0.17day^{-1}$. Although growth curves under N-existed and N-depleted conditions were almost the same, growth under N-depleted condition was relatively slowed (${\mu}=0.09$ to $0.14day^{-1}$), with a decreased maximum cell density. However, growth under the P-depleted condition was restricted for all temperatures, Two stains of Aphanizomenon flos-aquae were confirmed as not producing toxins, because saxitoxin and cylindrospermopsin were not detected by ELISA. The exudates or filtrates from the Aphanizomenon flos-aquae (DGUC003) resulted in significant inhibition of algal growth on the Aulacoseira ambigua f. spiralis (DGUD001) and Aphanizomenon flos-aquae (DGUC001) (p < 0.01).

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.422-429
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• 2013

The aim of this study was to investigate the characteristics of canine uropathogenic Escherichia coli (UPEC) and the interaction between canine UPEC and human bladder epithelial cells. Ten E. coli isolates collected from dogs with cystitis were analyzed for antimicrobial resistance patterns, the presence of virulence factors, and biofilm formation. The ability of these isolates to induce cytotoxicity, invade human bladder epithelial cells, and stimulate an immune response was also determined. We observed a high rate of antimicrobial resistance among canine UPEC isolates. All virulence genes tested (including adhesins, iron acquisition, and protectin), except toxin genes, were detected among the canine UPEC isolates. We found that all isolates showed varying degrees of biofilm formation (mean, 0.26; range, 0.07 to 0.82), using a microtiter plate assay to evaluate biofilm formation by the isolates. Cytotoxicity to human bladder epithelial cells by the canine UPEC isolates increased in a time-dependent manner, with a 56.9% and 36.1% reduction in cell viability compared with the control at 6 and 9 h of incubation, respectively. We found that most canine UPEC isolates were able to invade human bladder epithelial cells. The interaction between these isolates and human bladder epithelial cells strongly induced the production of proinflammatory cytokines such as IL-6 and IL-8. We demonstrated that canine UPEC isolates can interact with human bladder epithelial cells, although the detailed mechanisms remain unknown. The results suggest that canine UPEC isolates, rather than dogspecific pathogens, have zoonotic potential.

• 대한임상독성학회지
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• 제15권2호
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• pp.107-115
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• 2017

Purpose: Glehnia littoralis has been used to treat ischemic stroke, phlegm, cough, systemic paralysis, antipyretics and neuralgia. The pharmacological mechanisms of Glehnia littoralis include calcium channel block, coumarin derivatives, anticoagulation, anti-convulsive effect, as well as anti-oxidant and anti-inflammatory effects. Alpha-amanitin (${\alpha}$-amanitin) is a major toxin from extremely poisonous Amanita fungi. Oxidative stress, which may contribute to severe hepatotoxicity was induced by ${\alpha}$-amanitin. The aim of this study was to investigate whether Glehnia littoralis ethyl acetate extract (GLEA) has the protective antioxidant effects on ${\alpha}$-amanitin -induced hepatotoxicity. Methods: Human hepatoma cell line HepG2 cells were pretreated in the presence or absence of GLEA (50, 100 and $200{\mu}g/ml$) for 4 hours, then exposed to $60{\mu}mol/L$ of${\alpha}$-amanitin for an additional 4 hours. Cell viability was evaluated using the MTT method. AST, ALT, and LDH production in a culture medium and intracellular MDA, GSH, and SOD levels were determined. Results: GLEA (50, 100 and $200{\mu}g/ml$) significantly increased the relative cell viability by 7.11, 9.87, and 14.39%, respectively, and reduced the level of ALT by 10.39%, 34.27%, and 52.14%, AST by 9.89%, 15.16%, and 32.84%, as well as LDH by 15.86%, 22.98%, and 24.32% in culture medium, respectively. GLEA could also remarkably decrease the level of MDA and increase the content of GSH and SOD in the HepG2 cells. Conclusion: In the in vitro model, Glehnia littoralis was effective in limiting hepatic injury after ${\alpha}$-amanitin poisoning. Its antioxidant effect is attenuated by antidotal therapy.

• 한국식품과학회지
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• 제21권5호
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• pp.721-725
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• 1989

Aspergillus kawachii 혹은 A. shirousamii는 저장 중인 쌀에서 A. flavus에 의한 aflatoxin의 시발생성시기에는 영향을 주지 못하였으나 생성속도와 생성량은 현저하게 감소시키었다. 백미를 A. flavus로 접종하여 상대습도 85%, $28^{\circ}C$에서 저장하는 동안 aflatoxin $B_1$은 35일 후에 최고 $40{\mu}g/50g$ 생성되었다. 같은 조건에서 A. kawachii 동시접종한 경우에는 45일 후 최고 $25{\mu}g/50g$ 생성되었으나 A. shirousamii를 동시접종한 경우에는 60일 동안 흔적 정도만이 검출되었다. Aflatoxin을 첨가한 쌀에 A. kawachii 및 A. shirousamii를 7일간 키우면 각각 97% 및 98%의 aflatoxin이 감소되었다. 또한 aflatoxin을 첨가한 쌀을 A. kawachii 및 A. shirousamii로 만든 쌀 고오지로 48시간 당화시키는 동안 각각 30-67% 및 16-57%의 aflatoxin이 감소되었다.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.598-606
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• 2003

Salmonella encodes an enterotoxin (Stn) which possesses biological activity similar to the cholera toxin. Stn contributes significantly to the overall virulence of S. typhimurium in a murine model. The production of Stn is enhanced in a high-osmolarity medium and by contact with epithelial cells. In the present study, the in vitro and in vivo transcriptional regulations of the sin promoter revealed two promoters, P1 and P2. The P1 promoter identified by a primer extension analysis of stn mRNA exhibited a switching mechanism in vivo. Depending on the growth stage, transcription was initiated from different start sites termed $P1_S\;and\;P1_E$. $P1_S$, recognized by RNA polymerase containing ${\sigma}^S(E{\sigma}^S),\;and\;P1_E$, recognized by $E{\sigma}^70$, were activated during the stationary and exponential phases, respectively, while $P1_S\;and\;P1_E$ were both negatively regulated by CRPㆍcAMP and H-NS. Results revealed that $P1_S$ was the responsible promoter activated under a high osmolarity and low pH. The P2 promoter was identified 45 nucleotides downstream from $P1_E$ and negatively controlled by CRPㆍcAMP in vitro. No P2 activity was detected in vivo. The regulation of stn expression monitored using a Pstn::egfp fusion indicated that $E{\sigma}^S$ was required for the induction of stn and various factors were involved in stn regulation inside animal cells.

• The Korean Journal of Physiology and Pharmacology
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• 제19권1호
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• pp.51-57
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• 2015

The etiology of periodontal disease is multifactorial. Exogenous stimuli such as bacterial pathogens can interact with toll-like receptors to activate intracellular calcium signaling in gingival epithelium and other tissues. The triggering of calcium signaling induces the secretion of pro-inflammatory cytokines such as interleukin-8 as part of the inflammatory response; however, the exact mechanism of calcium signaling induced by bacterial toxins when gingival epithelial cells are exposed to pathogens is unclear. Here, we investigate calcium signaling induced by bacteria and expression of inflammatory cytokines in human gingival epithelial cells. We found that peptidoglycan, a constituent of grampositive bacteria and an agonist of toll-like receptor 2, increases intracellular calcium in a concentration-dependent manner. Peptidoglycan-induced calcium signaling was abolished by treatment with blockers of phospholipase C (U73122), inositol 1,4,5-trisphosphate receptors, indicating the release of calcium from intracellular calcium stores. Peptidoglycan-mediated interleukin-8 expression was blocked by U73122 and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester). Moreover, interleukin-8 expression was induced by thapsigargin, a selective inhibitor of the sarco/endoplasmic reticulum calcium ATPase, when thapsigargin was treated alone or co-treated with peptidoglycan. These results suggest that the gram-positive bacterial toxin peptidoglycan induces calcium signaling via the phospholipase C/inositol 1,4,5-trisphosphate pathway, and that increased interleukin-8 expression is mediated by intracellular calcium levels in human gingival epithelial cells.

• 방사선산업학회지
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• 제7권2_3호
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• pp.161-166
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• 2013

The purpose of this study was to investigate the cell proliferating and interleukin-2 producing activity of staphylococcal enterotoxin B by gamma-irradiation. Staphylococcal enterotoxin B was gamma-irradiated with the various doses of 0, 2, 20 and 50 kGy. SDS-PAGE analysis showed that gamma-irradiation caused the sharp decrease of the content of staphylococcal enterotoxin B and the effect was irradiating dose-dependent. Non-irradiated staphylococcal enterotoxin B increased the cell proliferation of splenocytes isolated from female Balb/c mouse, whereas 2 kGy-irradiated toxin significantly decreased the activity. 20 and 50 kGy-irradiated staphylococcal enterotoxin B was no effect. A similar effect on the interleukin-2 production of mouse splenocytes was observed with non-irradiated and irradiated staphylococcal enterotoxin B. It was considered to be due to the decrease of the antigenicity of staphylococcal enterotoxin B by gamma-irradiation. Therefore, these results suggest that gamma-irradiation can be effective for the decrease of the antigenicity of staphylococcal enterotoxin B as superantigen.