• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.355-361
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• 1986

Vibrio vulnificus, a halophilic Vibrio has gained worldwide attention as a cause of severe and frequently fatal wound infections and life-threatening septicemia. For this reason V. vulnificus is thought to produce extreme hemoconcentration and rapid death after infection, and because V. vulnificus is thought to be less susceptible to bactericidal activity of normal human serum, the present study was undertaken to assess the susceptibility of V. vulnificus to human serum bactericidal activity with that of V. parahemolyticus and V. cholerae and to assess the effect of Vibrio species, Salmonella typhimurium and E. coli on hematocrit values in experimentally infected mice. Serum bactericidal activity against both V. vulnificus and V. cholerae was higher than against V. parahemoltyicus. Survival of the test strains in heat-inactivated human serum was greater than that in heat-uninactiveted serum. Both V. parahemolyticus and V. cholerae produced slight hemoconcentration within 2 to 6 hr after intraperitoneal injection of $10^7$ viable bacteria into mice. In contrast, V. vulnificus, S. typhimurium and E. coli produced hemodilution rather than hemoconcentration after 4 or 6 hr after infection. With these results the author can conclude that V. vulnificus is more susceptible to serum bactericidal activity than other Vibrio species, and V. vulnificus did not produce hemoconcentration.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1299-1306
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine. Biologically synthesized silver nanoparticles have a wide range of applications. Materials and Methods: Silver nanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea, used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infra red (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). The biosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma ($HepG_2$) cell line cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic and antimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcus aureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar well diffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillin and Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively. Results: The biosynthesized AgNPs were $11.4{\pm}3.52$ nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residues and proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activity against the human hepatocellular carcinoma ($HepG_2$) cell line at higher concentrations. The results also showed that the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towards Bacillus subtillus. Conclusions: Cytotoxic activity of the biosynthesized AgNPs may be due to the presence of alkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B. subtillus).

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.143-147
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• 1996

LB20304 is a novel fluoroquinolone that exhibits a potent broad spectrum antibacterial activity against both gram-positve and gram-negative bacteria. The MICs (Minimal Inhibitory Concentration) of LB20304 were determined against both gram-positve and gram-negative bacteria under various conditions including several media, pHs, and inoculum concentrations. The in vitro activity of LB20304 was not significantly affected by the changes in testing conditions such as components of media and inoculum concentrations, but it was slightly reduced by acid condition. The MICs and MBCs (Minimal Bactericidal Concentration) of LB20304 against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were hardly affected by the presence of 50 % human serum, mouse serum, guinea pig serum or horse serum, and the MBCs were equal to or at most four-times higher than the MiCs. The activities of LB20304 were decreased by the presence of high concentraion of $Mg^{++}$ or human urine (pH, 5.5) in the test media. The frequencies of mutants resistant to LB20304 were similar to or lower than those found in ciprofloxacin and sparfloxacin.

• 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.