• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.301-310
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• 2000

The antimicrobial susceptibility, genotypes of enterotoxins(LT, STa) and pili(K88, 987P), and plasmid profiles were investigated with 102 Escherichia coli isolated from piglets showing diarrhea in Korea. Almost of them were susceptible to ceftiofur(99%), cefquinone(97.1%). However they showed resistance to bacitracin(100%), streptomycin(98%), vancomycin(97%), trimethoprim/sulfamethoxazole(87.2%), tetracycline(84.3%) in antimicrobial susceptibility test. Moreover, all of the isolates demonstrated resistance to more than 2, and 78% of them were resistant to more than 8 of total 17 drugs. Multiplex PCRs for genotyping of enterotoxins(LT, STa) and pili(K88, 987P) were established with primers designed based on sequences from Genebank. Seventeen strains(16.6%) of the isolates had STa gene, 11 strains(10.8%) of them had both STa and LT genes, and 18 strains(17.8%) had K88 gene. But none of the isolates harbored a gene exclusively encoding LT. The gene encoding 987P pili was not found in all isolates. Fifty-four strains of 102 isolates(52.9%) had plasmid with various sizes ranging from 125kb to 1.1kb. Numbers of plasmid per isolates were also various, from 1 to 9. Distinctive relationship between plasmid profiles and genotypes of enterotoxins and pili in the isolates was not found. These results might provide the basic knowledge to establish strategies for the treatment and prevention of colibacillosis in piglets.

• Applied Microscopy
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• v.11 no.1
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• pp.29-38
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• 1981

Bacteriophage f2 were treated with ozone at various concentrations for 20 minutes. The inactivation kinetics of f2 phage were examined during ozonation. In order to study the mode of action of ozone on the phage f2, absorption of the phage to the host pili was meassured by utilyzing radioactivity of tritium incorporated into the phage RNA. Sucrose density gradient analysis and electron microscopy were also used to prove the mechanism of ozone inactivation of the phage. Strucural proteins of the phage were broken by ozonation into many protein subunits. The extent of phage breakage was proportional to ozone concentration and reaction time. Percent decrease of the phage absorption to the host pili was coincident with the rate of ozone inactivation of the phage. Ozone inactivation of bacteriophage f2 was shown to be caused by the breakage of the structural protein and blockage of the phage absorption to the host pili.

• Environmental Engineering Research
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• v.18 no.4
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• pp.277-281
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• 2013

A dual-chamber microbial fuel cell (MFC) inoculated with Desulfovibrio desulfuricans and supplemented with lactate as an organic fuel was employed in this study. Biofilm formed on the anodic electrode was examined by scanning electron microscopy, revealing that the amount of biofilm was increased with repeated cycles of MFC operation. The maximum current production was notably increased from the first cycle ($1,310.0{\pm}22.3mA/m^2$) to the final cycle ($1,539.4{\pm}25.8mA/m^2$) of MFC run. Coulombic efficiency was also increased from $89.4%{\pm}0.2%$ to $98.9%{\pm}0.5%$. We suggest that the current production efficiency was related to the biomass of biofilm formed on the electrode, which was also increased as the MFC run was repeated. It was also found that D. desulfuricans, which colonized on the electrode, produced filaments or nano-pili. Nano-pili were effective for the attachment of cells on the electrode. In addition, the nano-pili provided a cell-to-cell link and stimulated the development of thicker electroactive biofilm, and therefore, they facilitated electron transfer to the anode. Conclusively, the biofilm of D. desulfuricans enhanced the current production in the MFC as a result of effective attachment of cells and electron transfer from the cell network to the electrode.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.199-205
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• 2002

Gliding motility is defined as the movement of nonflagellated cells in the direction of its long axis on a solid surface and found in many phylogenetically diverse bacteria. Genetic, biochemical, ultrastructural, and behavioral studies have provided a wealth of information related to the mechanism of possible gliding apparatuses. Social motility of Myxococcus xanthus and the gliding of Synechocystis appear to rely on the function of type IV pili, similar to twitching motility of pseudomonas aeruginosa and Neisseria gonorrhoeae. In contrast, adventurous motility of M. xanthus and the gliding of filamentous cyanobacteria and Flavobacterium are not dependent on the pili. Instead, they appear to employ novel motility mechanisms that are currently being unveiled.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.31-36
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• 2012

Lactobacillus rhamnosus GG(ATCC 53103) is one of the best researched probiotic strains in the world. Studies in children have shown that Lactobacillus rhamnosus GG effectively prevents early atopic disease in patients with high risk. The active molecules associated with the immunostimulatory sequence and anti-allergy effects of L. rhamnosus GG have not yet been identified. Unmethylated CpG motifs in bacterial DNA have a mitogenic effect in mouse immune cells, CpG-containing ISS oligodeoxynucleotides are potent Th1 adjuvants, effective in both preventing and reversing Th2-biased immune deviation in allergy models. The genomic DNA of L. rhamnosus GG is a potent inducer of murine B cell and dendritic cell immunoactivation. In L. rhamnosus GG genomic DNA, ID35 shows high activity in ISS assays in both mice and humans. The effects of ID35 result from a unique TTTCGTT motif located at its 5'-end, and its effects are comparable with murine prototype CpG 1826. L. rhamnosus GG is known to secrete proteinaceous pili encoded by the spaCBA gene cluster. The presence of pili structures may be essential for its adhesion to human intestinal mucus, explaining the prolonged duration of intestinal residence of this bacterium, compared to that of non-piliated lactobacilli.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.97-102
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• 1986

The prevalence of diarrhea caused by enterotoxigenic Escherichia coli was surveyed on 445 calves in 6 farms which were located in the central part of Korea. The incidence of enterotoxigenic Escherichia coli in calves with diarrhea was investigated by detecting the K99 and F41 antigens from the isolated strains of Escherichia coli The incidence of colibacillosis in calves was 23.3%. Of 238 strains of Escherichia coli isolated from calves with diarrhea, 73 strains(30.6%) were proved possessing the K99 antigen by mannose-resistant hemagglutination(MRHA) using horse red blood cells and 79(33.1%) possessing F41 antigens by MRHA using guinea-pig red blood cells. The minca medium, nutrient broth, tryptic soy broth and brain heart infusion were tested for yield of K99 and F41 pili. The production of pili was greatest in minea medium. The best detachment method of the K99 and F41 pili from the cells was heat treatment for 20 minutes at $60^{\circ}C$ and concentration by precipitation with ammonium sulfate. The purified antigens of K99 and F41 were polypeptides with molecular weights of 18,500 and 29,500, respectively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.525-537
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• 2024

Pilins are protein subunits of pili. The pilins of type IV pili (T4P) in pathogenic bacteria are well characterized, but anything is known about the T4P proteins in acidophilic chemolithoautotrophic microorganisms such as the genus Acidithiobacillus. The interest in T4P of A. thiooxidans is because of their possible role in cell recruitment and bacterial aggregation on the surface of minerals during biooxidation of sulfide minerals. In this study we present a successful ad hoc methodology for the heterologous expression and purification of extracellular proteins such as the minor pilin PilV of the T4P of A. thiooxidans, a pilin exposed to extreme conditions of acidity and high oxidation-reduction potentials, and that interact with metal sulfides in an environment rich in dissolved minerals. Once obtained, the model structure of A. thiooxidans PilV revealed the core basic architecture of T4P pilins. Because of the acidophilic condition, we carried out in silico characterization of the protonation status of acidic and basic residues of PilV in order to calculate the ionization state at specific pH values and evaluated their pH stability. Further biophysical characterization was done using UV-visible and fluorescence spectroscopy and the results showed that PilV remains soluble and stable even after exposure to significant changes of pH. PilV has a unique amino acid composition that exhibits acid stability, with significant biotechnology implications such as biooxidation of sulfide minerals. The biophysics profiles of PilV open new paradigms about resilient proteins and stimulate the study of other pilins from extremophiles.

• Biomedical Science Letters
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• v.2 no.1
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• pp.31-40
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• 1996

Escherichia coli is one of the most common etiological agents in urinary tract infection. An important virulence factor is the adhesive capacity of E. coli to uroepithelial cell, mediated by bacterial fimbriae. The Adhesion property has been regarded as an important virulence determinant in urinary tract infections. A total of 60 patients, who were diagnosed microbiologically as urinary tract infections, were examined by immunoblotting and enzyme-linked immunosorbent assay(ELISA). Uropathogenic E. coli with recombinant plasmid were positive for mannose resistant hemagglutination (MRHA). For identification of p-fimbriae subtype in uropathogenic E. coli, In the immunoblot analysis, specific bands in the range of p-fimbriae molecular weight of 17KD-22KD were identified. For the distribution of p-fimbriae subtype in the patient sera, 34/60(56.7%) were positive for $F7_1$, 28/60(46.7%) were positive for $F7_2$, and 30/60(50%) were positive for F13 with immunoblotting method. similar trends were observed in the enzyme-linked immunosorbent assay. Relatively good specificity(92.6%) and sensitivity(90%) were found in the ELISA test system using mixed antigens of purified $F7_1$, $F7_2$, and F13 p-fimbriae, and 60 sera from patients with urinary tract infections. In conclusion The serological tests were convenient method in diagnosis of urinary tract infections. among those ELISA could be recommended in diagnosis of urinary tract infections.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.110-110
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• 2003

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.10a
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• pp.256-257
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• 2003