• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.9 no.3
• /
• pp.339-346
• /
• 1999

We studied th physicochemical properties and the antibacterial effects of the Ag-treated activated carbon. The adsorption isotherms for the series of Ag-impregnated activated carbons represented typical Type-I. The surface area of the impregnated carbon was in the range of $740~1110\;m^{2}/g$, while the surface area of starting materials was $1440\;m^{2}/g$. Using t-plot, ${\alpha}_{s}$}-plot as well as DR-plot, and the volume of micropore was obtained. From the SEM study, the highly developed porous structure and the homogeneous distribution of Ag on the surface of activated carbon were confirmed. Finally, antibacterial effects of Ag-treated carbon aginst E. coli was discussed.

• Journal of Life Science
• /
• v.28 no.1
• /
• pp.78-82
• /
• 2018

Detection of pathogenic microorganisms takes several days by conventional methods. It is necessary to assess microorganisms in a timely manner to reduce the risk of spreading infection. For this purpose, bacteriophages are chosen for use as a biosensing tool due to their host specificity, wide abundance, and safety. However, their lytic cycle limits their efficacy as biosensors. Phage proteins involved in binding to bacteria could be a robust alternative in resolving this drawback. Here, a fragment of tail protein J (residues 784 to 1,132) of phage lambda fused with 6X His-tag (6HN-J) at its N-terminus was cloned, overexpressed, purified, and characterized for its binding with microorganisms. The purified protein demonstrated a size of about 38 kDa in sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) and bound with anti-His monoclonal antibodies. It bound specifically to Escherichia coli K-12, and not Salmonella typhimurium, Bacillus subtilis, or Pseudomonas aeruginosa in dot blotting. Binding of the protein to E. coli K-12 inhibited about 50% of the in vivo adsorption of the phage lambda to host cells at a concentration of $1{\mu}g/ml$ 6HN-J protein and almost 100% at $25{\mu}g/ml$ 6HN-J. The results suggest that a fusion viral protein could be utilized as a biosensing element (e.g., protein chips) for detecting microorganisms in real time.

• Microbiology and Biotechnology Letters
• /
• v.49 no.4
• /
• pp.510-518
• /
• 2021

Bacteriophages are considered excellent sensing elements for platforms detecting bacteria. However, their lytic cycle has restricted their efficacy. Here, we used the minor coat protein pIII domain (N1N2) of phage CTXφ to construct a novel surface plasmon resonance (SPR) biosensor that could detect Vibrio cholerae. N1N2 harboring the domains required for phage adsorption and entry was obtained from Escherichia coli using recombinant protein expression and purification. SDS-PAGE revealed an approximate size of 30 kDa for N1N2. Dot blot and transmission electron microscopy analyses revealed that the protein bound to the host V. cholerae but not to non-host E. coli K-12 cells. Next, we used amine-coupling to develop a novel recombinant N1N2 (rN1N2)-functionalized SPR biosensor by immobilizing rN1N2 proteins on gold substrates and using SPR to monitor the binding kinetics of the proteins with target bacteria. We observed rapid detection of V. cholerae in the range of approximately 10³ to 10⁹ CFU/ml but not of E. coli at any tested concentration, thereby confirming that the biosensor exhibited differential recognition and binding. The results indicate that the novel biosensor can rapidly monitor a target pathogenic microorganism in the environment and is very useful for monitoring food safety and facilitating early disease prevention.

• The Korean Journal of Food And Nutrition
• /
• v.18 no.4
• /
• pp.367-372
• /
• 2005

Antimicrobial effects of the extracts from Castanea crenata leaf were investigated. The antimicrobial effects of methanol extract (8 mg, 20 mg) of 0.2 g and 0.5 g. eq. of Castanea crenata leaf was stronger than that of 0.65 mg of benzoic acid against Gram(+) bacteria such as Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Leuconostoc mesenteroides and Bacillus subtilig and Gram(-) bacteria such as Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa. Growth inhibition of various microorganisms was observed in Castanea crenata leaf, therefor the Castanea crenata leaf were solvent fractionated. The ethyl acetate-soluble acidic and phenolic fraction were showed remarkable antimicrobial activity against microorganisms tested. The acidic fraction was purified with silica gel adsorption column chromatography, Sephadex LH-20 column chromatography and HPLC, subsequantly. The antimicrobial active substance isolated from the acid fraction of Castanea crenata leaf was characterized as stigmast-5-en-3-ol($\beta$-sitosterol) by MS and NMR analysis.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.1
• /
• pp.56-65
• /
• 1992

The complete nucleotide sequence of the Bacillus circulans F-2 RSDA gene, coding for raw starch digesting a-amylase (RSDA), has been determined. The RSDA structure gene consists of an open reading frame of 2508 bp. Six bp upstream of the translational start codon of the RSDA is a typical gram-positive Shine-Dalgarno sequence and the RSDA encodes a preprotein of 836 amino acids with an Mr of 96, 727. The gene was expressed from its own regulatory region in E. coli and two putative consensus promoter sequences were identified upstream of a ribosome binding site and an ATG start codon. Confirmation of the nucleotide sequence was obtained and the signal peptide cleavage site was identified by comparing the predicted amino acid sequence with that derived by N-terminal analysis of the purified RSDA. The deduced N-terminal region of the RSDA conforms to the general pattern for the signal peptides of secreted prokaryotic proteins. The complete amino acid sequence was deduced and homology with other enzymes was compared. The results suggested that the Thr-Ser-rich hinge region and the non-catalytic domain are necessary for efficient adsorption onto raw substrates, and the catalytic domain (60 kDa) is necessary for the hydrolysis of substrates, as suggested in previous studies (8, 9).

• Bulletin of the Korean Chemical Society
• /
• v.32 no.12
• /
• pp.4239-4243
• /
• 2011

Biocompatible hydrogels from 2-hydroxyethyl methacrylate (HEMA) monomer containing various amount of alginate in the presence and absence of hydrophilic methacrylic acid (MAA) were synthesized in order for biomedical application. The antimicrobial effect and interaction with proteins for hydrogels were investigated in this study. MAA was introduced because it was expected to increase the amount of water content in the polymer which is an important factor for biocompatibility, and alginate was expected to enhance the antimicrobial activity. The antimicrobial effect against S. aureus and E. coli increased for all hydrogels as the amount of alginate and MAA contained. Presence of MAA further enhances the antimicrobial effect. Amount of adsorption of bovine serum albumin (BSA) increased with increasing concentration of alginate whether MAA was present or not. Contrarily, the amount of lysozyme was not affected with increasing alginate concentration in the absence of MAA, while it decreased in the presence of MAA.

• Applied Biological Chemistry
• /
• v.39 no.6
• /
• pp.424-429
• /
• 1996

Inhibitory mechanism of colored rice bran against cellular genotoxicity induced by chemical mutagen was studied using organic solvent extracts from a colored rice cultivar termed as Suwon415, and the mutagen, mitomycin C. Inhibitory effects of 70% ethanol extact and chloroform fraction from rice bran of Suwon415 were higher than those from Chuchung used as control. However, antioxidative activities of each fraction from Suwon415 were slightly lower than those from Chuchung, suggesting the involvement of a different inhibitory mechanism not related to antioxidation pathway. Using E. coli as the indicator cell, inhibitory mechanism of rice bran extract from colored rice against mutagenicity induced by mitomycin C was investigated to reveal the possibility that it acts in a desmutagenic manner. Further investigation to quantify the free mitomycin C in reaction mixture following incubation with rice bran extract demonstrated that rice bran extract might inhibit the cellular genotoxicity of mitomycin C by direct adsorption of the mutagen.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.1 no.1
• /
• pp.43-48
• /
• 2000

Upon the Preparation of activated carbon fiber(ACF) using chemical activation method and vapour activation method, the fiber obtained from the vapour activation method shows excellent surface Properties. The preparation of antibacterial activated carbon fiber was tried to open the new areas in application of carbon materials. The BET specific surface area and the average pore radius of the antibacterial ACFs were in the range of 844.27~1575.6 $cm^2$/g and 10.6~12.9 (equation omitted), respectively. From the adsorption studies on the antibacterial ACFs, typical Type I isotherms were obtained. And, from the SEM morphology results, it was observed that the surface of ACFs was partially coated by antibacterial materials after the treatment. Finally, from the antibacterial effects of antibacteral ACFs against E. coli, excellent antibacterial activity was shown. Concerning the above results, antibacterial ACFs can have wide application in the areas of sterilization, anti-fragrant. anti-insects.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.7
• /
• pp.996-1004
• /
• 2020

Various genetically engineered microorganisms have been developed for the removal of heavy metal contaminants. Metal biosorption by whole-cell biosorbents can be enhanced by overproduction of metal-binding proteins/peptides in the cytoplasm or on the cell surface. However, few studies have compared the biosorption capacity of whole cells expressing intracellular or surface-displayed metal-adsorbing proteins. In this study, several constructs were prepared for expressing intracellular and surface-displayed Ochrobactrum tritici 5bvl1 ChrB in Escherichia coli BL21(DE3) cells. E. coli cells expressing surface-displayed ChrB removed more Cr(VI) from aqueous solutions than cells with cytoplasmic ChrB under the same conditions. However, intracellular ChrB was less susceptible to variation in extracellular conditions (pH and ionic strength), and more effectively removed Cr(VI) from industrial wastewater than the surface-displayed ChrB at low pH (<3). An adsorption-desorption experiment demonstrated that compared with intracellular accumulation, cell-surface adsorption is reversible, which allows easy desorption of the adsorbed metal ions and regeneration of the bioadsorbent. In addition, an intrinsic ChrB protein fluorescence assay suggested that pH and salinity may influence the Cr(VI) adsorption capacity of ChrB-expressing E. coli cells by modulating the ChrB protein conformation. Although the characteristics of ChrB may not be universal for all metal-binding proteins, our study provides new insights into different engineering strategies for whole-cell biosorbents for removing heavy metals from industrial effluents.

• Journal of Life Science
• /
• v.15 no.4 s.71
• /
• pp.566-571
• /
• 2005

A natural habitat bacterium, Enterobacter cloaceae K41 was isolated from fresh water plant root and identified. This strain was used to investigate heavy metal resistance. The optimal growth conditions of the bacterium were LB medium containing$1\%$ yeast extract, $1\%$ lactose, $1\%$ NaCl, pH 7.0, at $37^{\circ}C$, and for 24 hours on a shaker. The minimal inhibitory concentration (MIC) of heavy metals against E. cloaceae KCTC2519 and E. cloaceae K41 was compared. The MIC of E. cloaceae K41 was 150 ppm in Cu, 50 ppm in Cd whereas that of the standard strain was 50 ppm in Cu but no growth was observed either Cd or two mixed heavy metal solution. The presence of plasmid was cleared from the isolated strain whereas no possession from the standard strain. The plasmid from E. cloaceae K41 was transformed into E. coli $DH5{\alpha}$. The MIC of transformed strain increased resistance 7 times in Cu and 6 times in Cd by insertion of this plasmid. The metal adsorption of the transformant was increased 1.3 times in Cu and 1.5 times in Cd indicating the plasmid was responsible for heavy metal resistance.