• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.596-602
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• 2016

Staphylococcus aureus, like other gram-positive pathogens, has evolved a large repertoire of virulence factors as a powerful weapon to subvert the host immune system, among which alpha-hemolysin (Hla), a secreted pore-forming cytotoxin, plays a preeminent role. We observed a concentration-dependent reduction in Hla production by S. aureus in the presence of sub-inhibitory concentrations of isorhamnetin, a flavonoid from the fruits of Hippophae rhamnoides L., which has little antibacterial activity. We further evaluate the effect of isorhamnetin on the transcription of the Hla-encoding gene hla and RNAIII, an effector molecule in the agr system. Isorhamnetin significantly down-regulated RNAIII expression and subsequently inhibited hla transcription. In a co-culture of S. aureus and lung cells, topical isorhamnetin treatment protected against S. aureus-induced cell injury. Isorhamnetin may represent a leading compound for the development of anti-virulence drugs against S. aureus infections.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.59-62
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• 2002

The role of a TolC homologue in the virulence of Vibrio vulnificus, a marine bacterium causing serious wound infection and fulminant septicemia in persons with underlying conditions, has been studied. TolC, an outer membrane protein, has been implicated in a variety of bacterial functions including export of diverse molecules ranging from large proteins to antibiotics. A homologue of the tolC gene of V. cholerae, which has been shown to be required for bile resistance, cytotoxicity and colonization of this organism, was identified in the partially determined genome sequence of V. vulnificus. To determine the role of TolC in the virulence of V. vulnificus, a TolC-deficient (TD) mutant was isolated by in vivo allelic exchange. Compared with the parent strain, the TD mutant was more sensitive to bile, and much less virulent in mice challenged subcutaneously. This mutant was noncytotoxic to the HEp-2 cells, but its metalloprotease and cytolysin activities in the culture supernatant were comparable to the parent strain. In addition, the resistance of the TD mutant to human serum bactericidal activity as well as its growth in either human or murine blood was not affected. Collectively, our data suggest that TolC may be involved in colonization and/or spread of V. vulnificus to the blood stream, probably by secreting a cytotoxin other than the cytolysin.

• Korean Journal of Veterinary Service
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• v.21 no.4
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• pp.413-429
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• 1998

Escherichia coli is recovered from a wide variety of infections in many animals species. It may be a primary or secondary agent. Nursing and young animals are particularly susceptible, and urinary tract infections are frequent. The various serotypes of E coli are intestinal inhabitants of animals including humans and probably infect most mammals and birds : therefore, they have a cosmopolitan distribution. Colibacillosis refers to any totalized or systemic infection caused entirely or partly by E coli. Collibacillosis in mammals is most often a primary enteric disease, whereas collibacillosis in poultry is typically a secondary located or systemic disease occurring when host defenses have been impaired or overwhelmed. Other opportunistic bacteria, which can be identified by culture, may play a similar role to that of I coli in secondary infections. Collectively, infections caused by E coli are responsible for significant economic losses to the animal performance. From the standpoint of pathogenic mechanisms and diseases, four major categories of E coli are recognized : enterotoxigenic(ETEC), enteropathogenic (EPEC), enteroinvasive(EIEC), and enterohemorrhagic(EHEC). In addition, two less-well-defined E coli categories are recognized in animals and humans : enteroaggregative and cytotoxin necrotizing factor-positive. The aforementioned categories are represented by different serotypes. Certain serotypes show a host preference and are encountered more frequently in some disease syndromes. Of the four major categories, ETEC is the most common cause of diarrhea in calves, lambs, and pigs. Strains in the other categories cause the less-common diarrhea and other disease syndromes. Enterotoxins and pilus antigens are the two most prominent virulence factors thus far identified for ETEC. Two enterotoxins, one heat-stable(ST) and one heat-labile(LT), are produced by enterotoxigenic strains of E coli : not all culture produce both of these plasmid-based enterotoxins.

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.429-442
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• 1993

The cytotoxic effects of S hyodysenteriae strain B 204 on the mucosal surface were studied in surgically prepared ligated colonic loops in two male convenitonal mixed-breed pigs. In each one of four loops was inoculated with either sterile trypticase soy broth(TSB) of Serpulina, filtrate of Serpulina TSB culture. washed Serpulina cells or whole culture of Serpulina. Mucosal tissues were examined by transmission and scanning electron microscopy 24 and 48 hours after inoculation(p.i.). The filtrate did not induce any significant effect on the mucosal surface. The washed cells produced early lesions similar to those caused by the whole culture. These observations suggest that cytotoxins of the culture do not play a significant role in invasion of the epithelium in this experimental infection. The possible role of toxins associated with the organism at the site of interaction with the epithelial cells was not elucidated.

• Journal of Convergence for Information Technology
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• v.10 no.1
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• pp.243-250
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• 2020

Due to the unique sourness and sweet taste of Aronia, it is necessary to develop it for processing rather than raw. The antioxidant activity and cytotoxin about the aronia powder fermentation extract using lactobacillus are verified. In the case of total polyphenol content, the content of non-fermented extract was 32.15 ㎍/mg fermentation extract, 43.08 ㎍/mg after fermentation, and the flavonoid content was 0.47 ㎍/mg in non-fermented extract and 0.44 ㎍/mg in fermented extract, which was similar to that of non-fermented extract. In the DPPH radical inhibition assay, 77.5% of the non-fermented extract and 89.1% of the fermented extract showed better activity than the non-fermented extract. Nitric oxide (NO) measurement showed a concentration-dependent inhibitory effect. From the above results, it was confirmed that the fermentation of Aronia powder could be utilized based on some antioxidant activities and the possibility of using it as a vegetable extract and fermented cosmetic material in the future.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.478-487
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• 2000

This study was carried out to find new anti-tumor agent producing microbe and to characterize the anti-tumor agent produced from the microbe. Purified compound that has a high cytotoxicity against tumor cell-lines could be obtained from the broth culture filtrates of Streptomyces sp.409 strain isolated from soil in Korea. The in vitro cytotoxicity the in vivo evaluation of acute toxicity the safety assessment of the anti-tumor compounds and the taxonomic characteristics of the anti-tumor agent were measured. The antitumor compound 1 and 2 were obtained from the broth culture filtrates of Streptomyces sp.409 strain. The cytotoxicity of the compound 1 against tumor cell-line P388D$_1$ showed almost 4.5 times higher than that of adriamycin. However in the cytotoxicity against normal cell line Vero E6, adriamycin showed adversely 4 times higher than the compound 1 ($IC_{50}$/ value: 228.7 $\mu\textrm{g}$/$m\ell$). In comparison study with compound 1 and compound 2 in the in vitro cytotoxin productivity against tumor cell lines, $IC_{50}$/ value of the compound 1 was 0.25 $\mu\textrm{g}$/$m\ell$ in tumor cell line P388D$_1$and 0.53 $\mu\textrm{g}$/$m\ell$ in tumor cell-line L1210, and that of the compound 2 was 7.18 $\mu\textrm{g}$/$m\ell$ and 35.71 $\mu\textrm{g}$/$m\ell$, respectively; LD$_{50}$ value of the compound 1 in the in vivo acute toxicity in mice was 22.62 $\mu\textrm{g}$/kg body weight. These results suggest that compound 1 purified from Streptomyces sp. 409 has anti-tumor activity and will be developed as an anti-tumor drug.g.

• Biomolecules & Therapeutics
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• v.29 no.4
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• pp.410-418
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• 2021

Helicobacter pylori causes chronic gastritis through cag pathogenicity island (cagPAI), vacuolating cytotoxin A (VacA), lipopolysaccharides (LPS), and flagellin as pathogen-related molecular patterns (PAMPs), which, in combination with the pattern recognition receptors (PRRs) of host cells promotes the expression and secretion of inflammation-causing cytokines and activates innate immune responses such as inflammasomes. To identify useful compounds against H. pylori-associated gastric disorders, the effect of chalcone derivatives to activate the nucleotide-binding oligomerization domain (NOD)-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome was examined in an H. pylori-infected human monocytic THP-1 cell line in this study. Among the five synthetic structurally-related chalcone derivatives examined, 2'-hydroxy-4',6'-dimethoxychalcone (8) and 2'-hydroxy-3,4,5-trimethoxychalcone (12) strongly blocked the NLRP3 inflammasome in H. pylori-infected THP-1 cells. At 10 μM, these compounds inhibited the production of active IL-1β, IL-18, and caspase-1, and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) oligomerization, but did not affect the expression levels of NLRP3, ASC, and pro-caspase-1. The interruption of NLRP3 inflammasome activation by these compounds was found to be mediated via the inhibition of the interleukin-1 receptor-associated kinase 4 (IRAK4)/IκBα/NF-κB signaling pathway. These compounds also inhibited caspase-4 production associated with non-canonical NLRP3 inflammasome activation. These results show for the first time that certain chalcones could interrupt the activation of the NLRP3 inflammasome in H. pylori-infected THP-1 cells. Therefore, these chalcones may be helpful in alleviating H. pylori-related inflammatory disorders including chronic gastritis.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.260-269
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• 1998

This study was conducted to screen the biological activity of urushiol in the sap of lac tree(Rhus verniciflua STOKES) which has been used in traditional folk remedies. Cytotoxic activity of urushiol was screened with L1210(mouse luekemia cell), PC-9(human lung adenocarcinoma cell), A427(human lung adenocarcinoma cell) and KATO III (human stomach adenocarcinoma cell) The stepwise hexane : acetone eluent fractions of the urushiol were obtained by the silica gel adsorption column chromatography and added to the culture media containing L1210, PC-9. A427, and KATO III, respectively. A hexane : acetone(90 : 10, v/v) eluent fraction of them showed the lowest 50% inhibition concentration($IC_{50}$) of $0.018{\mu}g/m{\ell}$ for the cell line of A427. Much lower level of $IC_{50}$ of the hexane : acetone(90 : 10, v/v) eluent fraction of the urushiol showed the equal inhibition effect with tetraplatin(i.e., anti-cancer drug of platinum complexes) on the cancer cell lines as follows ; 3.4 times lower for L1210, 3.9 times lower for PC-9, and 105.5 times lower for A427. However, $IC_{50}$ of the hexane : acetone(90 : 10 v/v) eluent fraction for KATO III was exceptionally 3.9 times higher than that of tetraplatin.

• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.40-46
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• 2014

We have screened Bacillus strains suitable for the fermentation of soybean products with respect to the control of Bacillus cereus and the reduction of biogenic amines. Of 26 isolates, a strain named as the SCK A08 carried antimicrobial activity against B. cereus and Staphylococcus aureus, major food poisoning species in soybean products. PCR analysis revealed that the SCK A08 strain did not contain genes for Bacillus cereus toxins including nonhemolytic enterotoxin, hemolytic enterotoxin, cytotoxin K, cereulide and certrax. The SCK A08 strain could degrade histamine, tyramine, putrescine, and cadaverine by 67.41%, 76.59%, 57.32%, and 50.69%, respectively, during fermentation in cooked soybeans containing 0.5% (w/w) of each biogenic amine. The morphological and biochemical properties and phylogenetic relationships based on 16S rRNA gene sequences indicated that the isolate was most closely related to Bacillus licheniformis. Use of the strain SCK A08 would be a potential measure to overcome two hygienic problems that were frequently faced during manufacture of traditionally fermented soybean products.

• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.154-160
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• 2005

This study was performed to compare anticancer and immune activities between natural Artemisia capillaris Thunb. extract and tissue cultured plant extract (hairy root, in vitro culture, callus). The inhibitory effect of cancer cell growth, human B cell growth and productivity of cytokines were examined. Furthermore, HPLC analysis was performed to confirm the components. The anticancer activities increased by more than 55% with the cultured callus of Artemisia capillaris T. for four cancer cell lines(Lung carcunoma, Stomach adenocarcinoma, Hepatocillular carcinoma, Breast adenocarcinoma), showing higher effect than natural Artemisia capillaris T. The extracts from hairy root and in vitro culture of Artemisia capillaris T. significantly increased the immune B cell growth. The immune B cell growth effect of natural Artemisia capillaris T. was higher than that of the tissue culture plants such as hairy root, in vitro culture and callus. Both natural and tissue cultured plants showed similar effects on cytokine secretion. The similar peak size was observed between natural Artemisia capillaris T. and cultured callus in HPLC analysis. As a results, the biological activities were not observed the difference between natural Artemisia capillaris T. and cultured callus. Thus, the cultured callus will be altered natural Artemisia capillaris T. in the environmental side and the resources preservative side