• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.164-166
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• 2001

To examine the characteristics of the recombinant thin aggregative fimbriae of Salmonella, the AgfA subunit gene was amplified from Salmonella enteritidis using a PCR. The maltose binding protein (MBP)-AgfA fusion protein was overproduced in E. coli and purified. The secondary structure of AgfA was then elucidated from the difference CD spectra. An estimation of the secondary structure of AgfA using the self-consistent method revealed a mostly ${\beta}-sheet$ structure.

• Journal of Life Science
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• v.31 no.3
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• pp.330-337
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• 2021

This study was conducted to investigate the potential of Stewartia koreana as oral healthcare materials. The antibacterial activity of ethanol extracts from leaves and branches of S. koreana against oral bacteria was confirmed. The leaf and branch extracts (1 mg/disc) showed antibacterial activity against P. gingivalis only among several tested oral bacteria. The leaf extracts showed higher antibacterial activity, with values similar to those of chlorhexidine, which was used as a positive control. The MIC of the leaf extract against P. gingivalis was 0.4 mg/ml and showed bacteriostatic action. The inhibitory effects of the extract on biofilm formation and on gene expression related to biofilm formation by P. gingivalis were determined by biofilm biomass staining, scanning electron microscopy (SEM), and qRT-PCR analysis. The biofilm production rate and cell growth of P. gingivalis in the cultures treated with 0.2-2.0 mg/ml of S. koreana leaf extracts were significantly decreased in a concentration-dependent manner. The inhibitory effect on the formation of P. gingivalis biofilms at concentrations of 1 mg/ml was confirmed by SEM. The qRT-PCR analysis showed concentration-dependent suppression of the fimA and fimB gene expression associated with fimbriae formation in the cultures treated with 0.2-2.0 mg/ml S. koreana leaf extract. These results support the conclusion that S. koreana leaf extracts can be used as oral healthcare materials derived from natural materials, as demonstrated by the antibacterial action and inhibition of biofilm formation of P. gingivalis.

• Journal of Microbiology
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• v.44 no.5
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• pp.548-555
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• 2006

FaeG is the key factor in the infection process of K88ad enterotoxigenic Escherichia coli (ETEC) fimbrial adhesin. In an attempt to determine the possibility of expressing recombinant FaeG with immunogenicity for a new safe and high-production vaccine in E. coli, we constructed the recombinant strain, BL21 (DE3+K88), which harbors an expression vector with a DNA fragment of faeG, without a signal peptide. Results of 15% SDS-polyacrylamide slab gel analysis showed that FaeG can be stably over-expressed in BL21 (DE3+K88) as inclusion bodies without FaeE. Immunoglobulin G (IgG) and M (IgM) responses in pregnant pigs, with boost injections of the purified recombinant FaeG, were detected 4 weeks later in the sera and colostrum. An in vitro villius-adhesion assay verified that the elicited antibodies in the sera of vaccinated pigs were capable of preventing the adhesion of K88ad ETEC to porcine intestinal receptors. The protective effect on the mortality rates of suckling piglets born to vaccinated mothers was also observed one week after oral challenge with the virulent ETEC strain, $C_{83907}$ (K88ad, $CT^+,\;ST^+$). The results of this study proved that the adhesin of proteinaceous bacterial fimbriae or pili could be overexpressed in engineered E. coli strains, with protective immune responses to the pathogen.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.335-341
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• 2011

In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.543-552
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• 2020

For efficient prevention and treatment of enteric colibacillosis, understanding about latest virulence factors and antimicrobial resistance of Escherichia coli is essentially needed. The aim of this study was to survey antimicrobial resistance and determine the prevalence of fimbriae and enterotoxin genes among 118 pathogenic E. coli isolates obtained from Korean pigs with diarrhea between 2016 and 2017. The genes for the toxins and adhesins were amplified by polymerase chain reaction (PCR). The susceptibility of the E. coli isolates to antimicrobials were tested using the standard Kirby-Bauer disk diffusion method. The most prevalent fimbrial antigen was F18 (40.7%), followed by F4 (16.9%), and the most prevalent combinations of toxin genes were Stx2e (21.2%), STb:EAST-1 (19.5%), and STa:STb (16.9%), respectively. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most predominant (67.8%), followed by Shiga-toxin producing E. coli (STEC, 23.7%). We confirmed high resistance rates to chloramphenicol (88.1%), tetracycline (86.4%), streptomycin (86.4%), and ampicillin (86.4%). And the majorities of isolates (90.7%) showed multi-drug resistance which means having resistance to 3 or more subclasses of antimicrobials. Results of this study can be a source of valuable data for investigating the epidemiology of and control measures for enteric colibacillosis in Korean piggeries.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.542-551
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• 2017

Small phytochemicals have been successfully adopted as antibacterial chemotherapies and are being increasingly viewed as potential antibiofilm agents. Some of these molecules are known to repress biofilm and toxin production by certain bacterial and yeast pathogens, but information is lacking with regard to the genes allied with biofilm formation. The present study was performed to investigate the inhibitory effect of burdock root extract (BRE) and of chlorogenic acid (CGA; a component of BRE) on clinical isolates of Klebsiella pneumoniae. BRE and CGA exhibited significant antibiofilm activity against K. pneumoniae without inflicting any harm to its planktonic counterparts. In vitro assays supported the ${\beta}$-lactamase inhibitory effect of CGA and BRE while in silico docking showed that CGA bound strongly with the active sites of sulfhydryl-variable-1 ${\beta}$-lactamase. Furthermore, the mRNA transcript levels of two biofilm-associated genes (type 3 fimbriae mrkD and trehalose-6-phosphate hydrolase treC) were significantly downregulated in CGA- and BRE-treated samples. In addition, CGA inhibited biofilm formation by Escherichia coli and Candida albicans without affecting their planktonic cell growth. These findings show that BRE and its component CGA have potential use in antibiofilm strategies against persistent K. pneumoniae infections.

• Korean Journal of Ichthyology
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• v.7 no.1
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• pp.8-11
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• 1995

A stargazer fish, Ichthyscopus lebeck sannio, of family Uranoscopidae was collected for the first time in Cheju-shi, Cheju-do. Ichthyscopus lebeck sannio has several taxonomic characteristics : large white spots on the surface of body ; without cleithrum spine ; developed and branched labial fimbriae on the both lips ; triangular pectoral fin ; having fimbriated membranous projection on upper part of pectoral fin and having single dorsal fin.

• Korean Journal of Animal Reproduction
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• v.8 no.1
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• pp.10-15
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• 1984

This experiment was carried out to study the egg transports and distribution patterns in the oviducts of superovulated rabbits by administrations of PGF2$\alpha$. Group I (3 does) and Group II (3 does) were killed at 24 hours, 48 hours after mating, respectively. Group III (6 does0 received a single injection of 5mg/Kg of body weight of PGF2$\alpha$ at 24 hours after mating and killed at 4 hours after PGF2$\alpha$ administration. The oviducts were frozen in LN-gas, thawed using Howe's method, and cleared in Benzyl-Benzoate sol. using Orsini's technique. The location of the eggs and the AIJ. were identified using transmitted light from a dissecting microscope. The results obtained were as follows: 1. The average numbers of detected eggs from the oviduct were 28.6 (26-32), 26.0 (24-29), and 27.1 (22-34) in Group I, II, and III, respectively. 2. Detection rate was 88.7%, 76.4%, and 84.9% in Group I, II, and III, respectively. 3. The positionof all AIJ. was 44.2% to 55.0%(av. 49.5%) of the distance from the fimbriae to the UTJ.(Utero-Tubal Junction). 4. The changes of egg distribution patterns were as follows: Group I Ampulla : 52.3%, Isthmus : 47.7%, Group II Ampulla : 8.9%, Isthmus : 91.1% Group III Ampulla : 8.0% Isthmus : 92.0%.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.1
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• pp.95-98
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• 1993

Salpingoscopy may be helpful in the diagnosis of subclinical epithelial, vascular damage and stricture formation, which may playa significant role in infertility, or predispose women to tubal pregnancy, despite of clear demonstration of tubal patency on hysterosalpingogram. We explored the fallopian tube from the fimbriae to the ampullary-isthmic junction with small rigid flexible endoscope during laparoscopy in sixteen patients from July 1991 to Jan. 1992. All patients have been observed following salpingoscopy for several months. Three pregnancies were achieved in seven patients with bilaterally normal or minimally damaged tubal mucosa. In another five patients with moderate to severe tubal damage, we noted one tubal pregnancy. The other remaining patients are being followed up now. As conclusions, salpingoscopy seems to be an useful tool in the diagnosis of tubal lesions which are not identified by H.S.G., give much help to refine the indications for tubal microsurgery and the selection of patients for GIFT or IVF-ET and to determine the prognostic value in terms of risk for ectopic pregnancy.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.9-15
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• 2017

To construct a novel vaccine candidate against bovine enterotoxigenic Escherichia coli (ETEC), FanC, the major subunit of K99 fimbriae adhesion, was inserted into secretion plasmid pYA3560 containing a ${\beta}-lactamase$ secretion system. This was then transformed into ${\Delta}asd$ ${\Delta}crp$ Salmonella (S.) Typhimurium and designated as JOL950. Secretion of recombinant fanC fimbrial antigens was confirmed by immunoblot analysis. Groups of mice were inoculated with single or double doses of JOL950. Another group was used as a negative control. Compared to control mice, all immunized mice had significantly higher levels (p < 0.05) of serum immunoglobulin (Ig)G, and secretory IgA against FanC. The IgG2a and IgG1 titer assays revealed that immunization highly induced IgG2a compared to that of IgG1, indicating that T helper-1- related cell-mediated immune responses may be elicited by JOL950. The results show that both systemic and mucosal immunities against selected fimbrial antigens of bovine ETEC expressed by a live attenuated S. Typhimurium strain are prominently produced in mice immunized with JOL950 via an oral route.