• Journal of Microbiology and Biotechnology
• /
• v.14 no.6
• /
• pp.1190-1195
• /
• 2004

In recent years, there has been an intensive research on decolorization of dye and textile wastewater by various fungal strains. In this study, the decolorization ability of three commercial dyes, acid yellow 99, acid blue 350, and acid red 114, were investigated using 10 fungal strains. Among the fungal strains tested, Trametes versicolor KCTC 16781 completely decolorized all dyes in both solid and liquid experiments, and was also able to decolorize the mixture of those three dyes in liquid experiments. The secretion of the ligninolytic enzymes into the extracellular medium during decolorization by T versicolor KCTC 16781 was also studied. No lignin peroxidase activity was detected, and manganese peroxidase and laccase activities were investigated.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.5
• /
• pp.684-689
• /
• 2012

In the present study, an efficient mercury-tolerant bacterial strain (RS-5) was isolated from heavy-metalcontaminated industrial effluent. Under shake flask conditions, 97% of the supplemented mercuric chloride was sequestered by the biomass of RS-5 grown in a tryptone soy broth. The sequestered mercuric ions were transformed inside the bacterial cells, as an XRD analysis of the biomass confirmed the formation of mercurous chloride, which is only feasible following the reaction of the elemental mercury and the residual mercuric chloride present within the cells. Besides the sequestration and intracellular transformation, a significant fraction of the mercury (63%) was also volatilized. The 16S rRNA gene sequence of RS-5 revealed its phylogenetic relationship with the family Bacillaceae, and a 98% homology with Lysinibacillus fusiformis, a Gram-positive bacterium with swollen sporangia. This is the first observation of the sequestration and volatilization of mercuric ions by Lysinibacillus sp.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.10a
• /
• pp.109-117
• /
• 2000

Bacterial community structure composing enhanced biological phosphorus removal (EBPR) activated sludge was analyzed phylogenetically by cloning 165 rDNA after direct DNA extraction. Then, this result was compared with 165 rDNA sequences of randomly isolated bacterial species. The results clearly showed that there are no coincidence between the sequences retrieved directly from activated sludge and those of isolated strains, suggesting that many important bacteria are hidden in activated sludge because of the difficulty in isolation and culture of them.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.1
• /
• pp.64-68
• /
• 2013

Previous studies have shown that lactic acid bacteria can inhibit inflammatory responses, but the mechanisms are very little known. In this study, transaction and expression of three proinflammatory factors, iNOS, PTGS-2, and IL8, which are closely related to the inflammatory response, were investigated by luciferase reporter assay and RTPCR in HT-29 cells treated by Lactobacillus acidophilus. The results showed that the live L. acidophilus sharply down-regulated the transcription of these three genes. Because there was a NF-${\kappa}B$ binding site located at -265 bp, -225 bp, and -95 bp upstream of the iNOS, PTGS-2, and IL8 promoters, respectively, we further addressed the effects of NF-${\kappa}B$ on transaction of the three promoters by cotransfection. As was expected, NF-${\kappa}Bs$ remarkably upregulated the activity of the reporter gene and, no effect of NF-${\kappa}B$s on IL-8 promoter transaction was found after NF-${\kappa}B$ binding site mutation of the IL8 promoter in HT-29 cells. In conclusion, the live L. acidophilus decreased the transcriptional activity of NF-${\kappa}B$ and, in turn, inhibited the transaction of NF-${\kappa}B$ on the three proinflammatory factors mentioned above.

• Molecules and Cells
• /
• v.20 no.1
• /
• pp.83-89
• /
• 2005

HtrA2/Omi is a mammalian mitochondrial serine protease homologous to the E. coli HtrA/DegP gene products. Recently, HtrA2/Omi was found to have a dual role in mammalian cells, acting as an apoptosis-inducing protein and being involved in maintenance of mitochondrial homeostasis. By screening a human brain cDNA library with $A{\beta}$ peptide as bait in a yeast two-hybrid system, we identified HtrA2/Omi as a binding partner of $A{\beta}$ peptide. The interaction between $A{\beta}$ peptide and HtrA2/Omi was confirmed by an immunoblot binding assay. The possible involvement of HtrA2/Omi in $A{\beta}$ peptide metabolism was investigated. In vitro peptide cleavage assays showed that HtrA2/Omi did not directly promote the production of $A{\beta}$ peptide at the ${\beta}/{\gamma}$-secretase level, or the degradation of $A{\beta}$ peptide. However, overexpression of HtrA2/Omi in K269 cells decreased the production of $A{\beta}40$ and $A{\beta}42$ by up to 30%. These results rule out the involvement of HtrA2/Omi in the etiology of Alzheimer's disease. However, the fact that overexpression of HtrA2/Omi reduces the generation of $A{\beta}40$ and $A{\beta}42$ suggests that it may play some positive role in mammalian cells.

• Parasites, Hosts and Diseases
• /
• v.52 no.3
• /
• pp.311-315
• /
• 2014

The aim of this study was to verify the trypanocidal effectiveness of aqueous, methanolic, and ethanolic extracts of Achyrocline satureioides against Trypanosoma evansi in vitro. A. satureioides extracts, known as macela, were used on trypomastigotes at different concentrations (1, 5, 10, 50, 100, 500, and $1,000{\mu}g/ml$) and exposure times (0, 1, 3, 6, and 9 hr). A dose-dependent effect was observed when the 3 extracts were tested. The concentrations of 1, 5, and $10{\mu}g/ml$ were not able to kill trypomastigotes until 3 hr after exposure, and the highest concentrations (500 and $1,000{\mu}g/ml$) were able to kill all trypomastigotes after 1 hr. When the time of exposure was increased up to 9 hr, the concentrations at 50 and $100{\mu}g/ml$ were 100% effective to 3 extracts. The chemical analysis of the extracts revealed the presence of flavonoids, a trypanocidal compound already described. Based on the results, we can conclude that the A. satureioides extracts exhibit trypanocidal effects.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1605-1613
• /
• 2010

Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth promotion triggered by P. polymyxa isolates were systemically investigated on pepper for the first time. The P. polymyxa KNUC265 strain, which elicited both ISR and plant growth promotion, could be potentially used in improving the yield of pepper and possibly of other crops.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2002.10a
• /
• pp.80-80
• /
• 2002

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2002.10a
• /
• pp.89-91
• /
• 2002

• Journal of Microbiology and Biotechnology
• /
• v.26 no.7
• /
• pp.1341-1341
• /
• 2016