• Korean Journal of Microbiology
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• v.35 no.3
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• pp.248-252
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• 1999

The PI-oduction of virulence factors such as cholera toxin, heinolysin and hemagglutinin in V cliolerae non-01 and non-0139 were examined. Among 65 strains isolated from environmental and clinical blood sources, 29 (14.6%) strains produced hemolysin only, 35(53.9%) sh.ains produced both hemolysin and hemagglutinin. From one 037 slrain isolated from environmenl, cholera toxin, ctx gene, hemolysin, and hemagglutinin were detected. All of the strains isolated from clinical and environmental sources showed hemolytic activity against human 0 group e~ythrocytes. In inhibition patterns of heinagglotination, 5 of 18 clinical strains (27.8%) were inhibited by less than 1% mannose and galactose, while, among the 47 environmental isolates. hose paltems by less than 1% mannose and galactose 55.4% wel-e inhibited. Thel-ehre, exohamagglutinin positive rate was high in clinical blood isolates but in environnlental sources, the rate was almost similar lo ihe rate or endohemagglutinin positive. These results indicaled that V cholerae non-01 and non-0139 produced various virnlence factors such as cholera toxin, hemolysin, and hemagglutinin but not a single factor. Further studies are need for epidemiological or bacteriological shtdies of V cholerae 037 isolated from environment.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.253-261
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• 1993

Possible changes in the role of insulin-sensitive cyclic nucleotide phosphodiesterase(PDE) in mediating the antilipolytic action of insulin were investigated in adipocytes from streptozotocin-induced diabetic rats. Isolated adipocytes prepared from epididymal adipose tissue were incubated, with or without insulin, at $37^{\circ}C$ for 15 min following pretreatment with various drugs or toxins, and three (plasma membranes, microsomal membranes, and cytosol) fractions prepared by differential centrifugation were then assayed for cAMP phosphodiesterase activity. The PDE activities only in the crude microsomal (P2) fractions were activated by insulin both in diabetic and control rats. The basal PDE activities in P2 fractions of adipocytes from diabetic rats were higher than those from control rats, although the maximal effects observed at 2 nM of insulin, $100\;{\mu}M$ of isoproterenol or the combination of both were not significantly different from each other. The insulin-stimulated PDE activities in P2 fractions of adipocytes from diabetic rats were not changed by PIA, a $A_{1}$ adenosine receptor agonist, whereas they were decreased to the basal PDE activities in those from control rats. In addition, the adipocytes from diabetic rats showed an increased sensitivity to pertussis toxin compared to those from controls. There were no differences between diabetic and control rats in the sensitivity of adipocytes to cholera toxin. These data indicate that the impaired signalling through inhibitory receptors such as adenosine receptors in adipocytes from streptozotocin-induced diabetes relates to the loss or the decreased function of $G_i$ proteins, and leads to the increased activity of the insulin-dependent PDE at the basal states.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.478-482
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• 2005

Bovine k-casein macropeptide was prepared by adding TCA (3, 6, and $12\%$) treatment after chymosin reaction. Each TCA soluble macropeptide was fractionated into five peak by ion exchange column chromatography. In proportiion to TCA concentrations, the ratio of peak area showed different the elution pattern. At the 6 and $12\%$ TCA concentration, area ratio of P-I which did not content carbohydrates was decreased to 19.9 and $17.0\%$ of total peak area respectively. The area of P-III was changed from $10.2\%\;to\;26.2\;and\;13.2\%$ when the TCA concentration was increased from 3 to 6 and $12\%$ Cholera toxin binding activity of k-casein macropeptide eluted at $0.17\~0.18M$ NaCl gradient was not inhibited by 6 and $12\%$ TCA treatments. The use of $6\%$ TCA as extraction buffer was feasible and led to an effective separation of the peak III.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.177-178
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• 2002

병윈성 비브리오균의 병원인자에는 hemolysin, protease, phospholipase A2, siderophore 외에도 콜레라균 만이 생산하는 cholera toxin 등이 있다. 이 중에서도 대부분의 병원성 비브리오균에서 생성되는 대표적인 인자는 hemolysin과 protease로 알려져 있다. Hemolysin은 혈액을 분해하는 독소로서 병원성 비브리오균의 분리ㆍ동정에 널리 이용 되고 있다. Hemolysin은 균의 배양초기에서 부터 서서히 생성되기 시작하여 대수증식기 말에 최대의 활성을 나타내며 안정기에 접어들면서 활성이 급격히 감소되는 것으로 보고되고 있다 (Kim et al., 1997). (중략)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.309.2-309.2
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• 2002

The FimH subunit of type l-fimbriated Escherichia coli has been determined as a major cause of urinary tract infection. To produce a possible vaccine antigen against urinary tract infection, the fimH gene was genetically coupled to the ctxa2b gene, which was then cloned into pMAL -p2E expression vector. The chimaeric construction of pMALfimH/ctxa2b was transformed into Escherichia coli TB1 and its N-terminal amino acid sequence was analyzed. (omitted)

• Animal cells and systems
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• v.2 no.1
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• pp.93-97
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• 1998

Coelomoic fluid protein (CP), a vitellogenin contained in the coelomic fluid of polychaetes, is transported by receptor-mediated endocvtosis that is controlled by GTP-binding proteins. Transport of 125l-CP was markedly inhibited by AlF4 and toxins such as cholera toxin and pertussis toxin. These effects appear to be mediated by cAMP, since 125l-CP transport was also greatly inhibited by dibutyryl cAMP. The results strongly suggest that hetero trimeric G-protein is involved in the regulation of 125l=CP transport through the activation of adenylyl cyclase. Immunoblotting tests with antibodies against Gsa and Gia subunits showed a Gsa subunit of 45 kDa in the membrane of oocytes of intermediate and large size classes and a Gia subunit of 41 kDa only in the oocytes of the intermediate size class.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.816-820
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• 2018

The stringent response (SR), which is activated by accumulation of (p)ppGpp under conditions of growth-inhibiting stresses, plays an important role on growth and virulence in Vibrio cholerae. Herein, we carried out a genome-wide screen using transposon random mutagenesis to identify genes controlled by SR in a (p)ppGpp-overproducing mutant strain. One of the identified SR target genes was flaC encoding flagellin. Genetic studies using flaC and SR mutants demonstrated that FlaC was involved in bacterial growth, toxin production, and normal flagellum function under conditions of high (p)ppGpp levels, suggesting FlaC plays an important role in SR-induced pathogenicity in V. cholerae.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.865-872
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• 2000

Helocobacter phylori is the major cause of gastritis, peptic ulcer, and a principal risk factor for gastric cancer. As the firs step towards a vaccine against H. pylori infection, Hy.pylori urease was expressed and purified as a recombinant apoenzyme (rUrease) in E. coli. In order to develop an effective immunization protocol using rUrease, the host immune responses were evaluated after the oral immunization of mice with rUrease preparations plus cholera toxin relative to various conditions, such as the physical nature of the antigen, the frequency of the booster immunization, the dose of the antigen, and the route of administration. The protective efficacy was assessed using a quantitative culture following an H. pylori SS1 challenge. It was demonstrated that rUrease, due to its particulated nature, was more superior than the UreB subunit as a vaccine antigen. The oral immunization of rUrease elicited significant systemic and secretory antibody responses, and activated predominantly Th2-type cellular responses. The bacterial colonization was significantly reduced (~100-fold) in those mice immunized with three or four weekly oran doses of rUrease plus cholera toxin (p<0.05), when compared to the non-immunized/challenged controls. The protection correlated well with the elicited secretory IgA level against rUrease, and these secretory antibody responses were highly dependent on the frequency of the booster immunization, yet unaffected by the dose of the antigen (25-200$\mu\textrm{g}$). These results demonstrate the remarkable potential of rUrease as a vaccine antigen, thereby strengthening the possibility of developing an H. pylori vaccine for humans.

• Biomolecules & Therapeutics
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• v.11 no.3
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• pp.157-162
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• 2003

The generation of secretory IgA antibodies(Abs) for specific immune protection of mucosal surfaces depends on stimulation of the mucosal immune system, but this is not effectively achieved by parenteral or even oral administration of most soluble antigens. Thus, to produce a possible vaccine antigen against urinary tract infections, the uropathogenic E. coli (UPEC) adhesin was genetically coupled to the ctxa2b gene and cloned into a pMAL-p2E expression vector. The chimeric construction of pMALfimHIctxa2b was then transformed into E. coli K-12 TB1 and its nucleotide sequence was verified. The chimeric protein was then purified by applying the affinity chromatography. The purified chimeric protein was confirmed by SDS-PAGE and western blotting using antibodies to the maltose binding protein (MBP) or the cholera toxin subunit B (CTXB), plus the N-terminal amino acid sequence was analyzed. The orderly-assembled chimeric protein was confirmed by a modified $G_{M1}$-ganglioside ELISA using antibodies to adhesin. The results indicate that the purified chimeric protein was an Adhesin/CTXA2B protein containing UPEC adhesin and the $G_{M1}$-ganglioside binding activity of CTXB. This study also demonstrate that peroral administration of this chimeric immunogen in mice elicited high level of secretory IgA and serum IgG Abs to the UPEC adhesin. The results suggest that the genetically linked CTXA2B acts as a useful mucosal adjuvant, and that the adhesin/CTXA2B chimeric protein might be a potential antigen for oral immunization against UPEC.

• Toxicological Research
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• v.18 no.2
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• pp.205-213
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• 2002

This study was undertaken to develop a subacute murine model for predicting occurrence of systemic anaphylaxis and to evaluate efficacy of various immunological parameters as the monitoring indices for the occurrence of anaphyalxis. The murine anaphyalxis model was developed through intraperitoneally sensitizing 100 $\mu\textrm{g}$ ovalbumin (OVA) in the presence of 1 mg alum and 300 ng cholera toxin twice a week interval followed by challenging 500 $\mu\textrm{g}$. OVA intravenously. Typical anaphylaxis symptoms were demonstrated at the both BALB/c mice, a strain prone to type-2 response, and C57BL/6 mice. a strain prone to type-1 response. Level of plasma histamine was approximately 50-fold or 30-fold higher in the mice sensitized with OVA than the mice sensitized with alum plus cholera toxin or the saline-treated mice after OVA challenge, respectively. Sensitization and challenge with OVA significantly enhanced plasma leukotriene $B_4$ level but not IgE levels in comparison with the control mice, which indicated the role of leukotriene $B_4$ for progression of anaphyalxis. Furthermore, among mice suffered from anaphylaxis, levels of OVA-specific IgGl were significantly higher in the BALB/c mice than in the C57BL/6 mice, which implied the genetic susceptibility for the induction of systemic anaphylaxis. Conclusively, simultaneous evaluation of histamine, leukotriene $B_4$, and allergen-specific IgG isotype may serve as more efficient monitoring tool for vaccine-related anaphyalxis.