• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.355-356
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• 2000

Three 'stress probe' plasmids were constructed and characterized which utilize a green fluorescent protein (CFP) as a non-invasive reporter to elucidate Escherichia coli cellular stress responses in quiescent or 'resting' cells. Facile detection of cellular stress levels was achieved by fusion of three heat shock stress protein promoter elements, those of the heat shock transcription factor ${\sigma}^{32}$, pretense subunit ClpB, and chaperone DnaK, to the reporter gene $gfp_{uv}$. When perturbed by chemical or physical stress (such as heat shock, nutrient (amino acid) limitation, addition of IPTG, acetic acid, ethanol, phenol, antifoam, and salt (osmotic shock), the E. coli cells produced GFPuv which was easily detected from within the cells as emitted green fluorescence. A temporal and amplitudinal mapping of these responses was performed, demonstrating regions where quantitative delineation of cell stress was afforded.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.125-125
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• 2001

B cell has been identified as the sensitive cellular target responsible for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) -induced immune suppression. In isolated cell systems, the differentiation of B cells into antibody secreting plasma cells is believed to be inhibited by TCDD. We also have previously demonstrated IgM secretion was suppressed by TCDD in LPS-activated murine B cell line, CH12.LX.(omitted)

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.176-182
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• 1994

The light-organ symbiont of pine cone fish, Vibrio fischeri, senses its presence in the host and responds to environmental changes by differentially expressing its symbiosis-related luminescence genes. The V. fischeri luminescence genes are activated by LuxR protein in the presence of an autoinducer. In an effort to elucidate the mechanism of regulation of luxR, a plasmid containing luxR was mutagenized in vitro with hydroxylamine and a luxR mutant plasmid was isolated by its ability to activate luminescence genes cloned in E. coli in the absence of the autoinducer. The specific base change identified by DNA sequencing was only single base transition at ＋78 from the transcriptional start of luxR. Based on a Western immunoblot analysis, the nucleotide change directed the synthesis of much higher level of LuxR protein without any amino acid substitutions. The results suggest that the region including the ＋78th base is presumably internal operator required for autorepression of luxR, and the increased cellular level of LuxR results in activation of luminescence genes by autoinducer independent fashion.

• The Korean Journal of Mycology
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• v.50 no.2
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• pp.125-130
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• 2022

The powdery mildew found on Magnolia kobus was recorded as Microsphaera alni for the first time in Korea in 1975. After splitting M. alni into several distinct species, this mildew was regarded as Microsphaera magnifica, now Erysiphe magnifica. Since E. magnifica is known to be a North American species, the powdery mildew found on M. kobus in Korea was studied to clarify its identity. Based on morphological characteristics and sequencing results of the internal transcribed spacer and large subunit rDNA gene, the powdery mildew found on M. kobus in Korea was identified as Erysiphe magnoliicola.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.895-903
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• 2007

As for the increasing demanding on the development of direct-ecological landfill monitoring methods, it is needed for critically defining the condition of landfills and their influence on the environment, quantifying the amount of enzymes and bacteria mainly concerned with biochemical reaction in the landfills. This study was thus conducted to understand the fates of contaminants in association with groundwater quality parameters. For the study, groundwater was seasonally sampled from four closed unsanitary landfills(i.e. Cheonan(C), Wonju(W), Nonsan(N), Pyeongtaek(P) sites) in which microbial diversity was simultaneously obtained by 16S rDNA methods. Subsequently, a number of primer sets were prepared for quantifying the specific gene of representative bacteria and the gene of encoding enzymes dominantly found in the landfills. The relationship between water quality parameters and gene quantification were compared based on correlation factors. Correlation between DSR(Sulfate reduction bacteria) gene and BOD(Biochemical Oxygen Demand) was greater than 0.8 while NSR(Nitrification bacteria-Nitrospira sp.) gene and nitrate were related more than 0.9. A stabilization indicator(BOD/COD) and MTOT(Methane Oxidation bacteria), MCR(Methyl coenzyme M reductase), Dde(Dechloromonas denitrificans) genes were correlated over 0.8, but ferric iron and Fli(Ferribacterium limineticm) gene were at the lowest of 0.7. For MTOT, it was at the highest related at 100% over BOD/COD. In addition, anaerobic genes(i.e., nirS-Nitrite reductase, MCR. Dde, DSR) and DO were also related more than 0.8, which showing anaerobic reactions generally dependant upon DO. As demonstrated in the study, molecular biological investigation and water quality parameters are highly co-linked, so that quantitative real-time PCR could be cooperatively used for assessing landfill stabilization in association with the conventional monitoring parameters.

• Korean Journal of Veterinary Service
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• v.42 no.3
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• pp.153-159
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• 2019

The objective of this study was to identify mutations in the quinolone resistance determining region (QRDR) of the gyrA, gyrB, parC and parE genes, and the presence of plasmid-mediated quinolone resistance (PMQR) genes: qnrA, qnrB, qnrS, aac(6')-lb-cr and qepA in 40 nalidixic acid- resistant ($NA^R$) Salmonella isolates isolated from poultry slaughterhouse. The MIC of NA and ciprofloxacin for 40 $NA^R$ Salmonella isolates was $128{\sim}512{\mu}g/mL$ and < $0.125{\sim}0.25{\mu}g/mL$, respectively. The Salmonella isolates were resistant to NA (100%), gentamicin (5.0%) and ampicillin (2.5%). All $NA^R$ Salmonella isolates represented point mutation in codons Aspartic acid(Asp)-87 (90%) and Serine(Ser)-83 (10%) of QRDR of gyrA gene: $Asp87{\rightarrow}glycine$, $Ser83{\rightarrow}tyrosine$. No mutations were observed in QRDR of the gyrB, parC and parE gene. Moreover PMQR genes was not found in any of the tested isolates. Our findings showed that DNA gyrase is the primary target of quinolone resistance and a single mutation in codon Asp87 and Ser83 of the gyrA gene can confer resistance to NA and reduced susceptibility ciprofloxacin in Salmonella isolates.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11a
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• pp.76-100
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• 2000

A brief general discussion of the nature and function of biosensors is presented. While the primary motivator for biosensor development has been the health-care industries, recent research efforts have spread to problems in agriculture and biological production systems. To illustrate some of the research from our laboratory, three example biosensors and their corresponding applications are presented. The first of these is an immunosensor for measurement of the hormone progesterone during milking as a method to improve reproductive management of dairy herds. The second example is an enzyme sensor for measurement of urea in milk as a menas to determine the efficiency of conversion of input protein to milk protein and, thus, improve nutritional management of dairy herds. The third example is a DNA sensor using polymerase chain reaction to detect pathogenic bacteria in the wash water of fresh and minimally processed fruits and vegetables. The potential for application of biosensors in agriculture, agrobiotechnology, food processing, and environmental monitoring has barely been realized.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.04a
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• pp.295-303
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• 2009

The annals of Joseon dynasty, especially the volumes of King SeJong(1418-1450 A.D.), were heavily deteriorated by fungi. Investigations on the deteriorating and foxing fungi were carried out. Fungal structures on the beeswax, which were coated on the both side of Han-Ji, were suspected to be involved in the deterioration, and were observed by SEM. Isolation and culturing of these fungi were tried by scrubing swab samples and placing on the artificial media. Culture-independent approaches were used to identify the fungal strains associated with damages of beeswax and foxing of the paper by the analyses based on DNA sequences data from the specific ITS region of rDNA regions. In addition, well-known paper staining fungi(PSF), i.e., Aspergillus terreus var. terreus, Fusarium oxysporum, Chaetomium globosum, Cladosporium cladosporioides, and Alternaria solani, were compared in the mycelial growth and stain on beeswax and papers under different environmental conditions (temperature, light, moisture, etc). Fungal strains isolated from the air samples in the storage room and shelves were identified as Irpex sp., Arthrinium sacchari, Cladosporium tenuissimum, Aspergillus sclerotiorum, Sistotrema brinkmannii, and Hypoxylon bovei var. microsporum The isolated strains were compared in growth and stain patterns on beeswax and papers(Han-Ji, Hwa-Ji, and Yang-Ji) whether these can cause damage or foxing on the annals or not.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.798-807
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• 2008

Due to economic impairment derived from metal corrosion of pumping station installed around coastal area, it was needed for related cause-effect to be investigated for understanding practical corrosion behavior and providing proper control. This research was thus carried out to determine whether the microbe can influence on metal corrosion along with its control in the laboratory. For this study, groundwater was sampled from the underground pump station(i.e. I Gas Station) where corrosion was observed. Microbial diversity on the samples were then obtained by 16S rDNA methods. From this, microbial populations showing corrosion behaviors against metals were reported as Leptothrix sp.(Iron oxidizing) and Desulfovibrio sp.(Sulfur reducing) Iron oxidizing bacteria were dominantly participating in the corrosion of iron, while sulfate reducing bacteria were more preferably producing precipitate of iron. In case of galvanized steel and stainless steel, iron oxidizing bacteria not only enhanced the corrosion, but also generated its scale of precipitate. Sulfate reducing bacteria had zinc steel corroded greater extent than that of iron oxidizing bacteria. In the inactivation test, chlorine or UV exposure could efficiently control bacterial growth. However as the inactivation intensity being increased beyond a threshold level, corrosion rate was unlikely escalated due to augmented chemical effect. It is decided that microbial corrosion could be differently taken place depending upon type of microbes or materials, although they were highly correlated. It could be efficiently retarded by given disinfection practices.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.710-716
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• 2016

Gamma-aminobutyric acid (GABA) is a non-protein amino acid, which is an important inhibitor of neurotransmission in the human brain. GABA is also used as the precursor of biopolymer Nylon-4 production. In this study, the carbon flux from the tricarboxylic acid cycle was directed to the GABA shunt pathway for the production of GABA from glucose. The GABA shunt enzymes succinate-semialdehyde dehydrogenase (GabD) and GABA aminotransferase (GabT) were co-localized along with the GABA transporter (GadC) by using a synthetic scaffold complex. The co-localized enzyme scaffold complex produced 0.71 g/l of GABA from 10 g/l of glucose. Inactivation of competing metabolic pathways in mutant E. coli strains XBM1 and XBM6 increased GABA production 13% to reach 0.80 g/l GABA by the enzymes co-localized and expressed in the mutant strains. The recombinant E. coli system developed in this study demonstrated the possibility of the pathway of the GABA shunt as a novel GABA production pathway.