• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.153-166
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• 1995

54 clinical isolates of Actinobacillus actinomycetemcomitans showed distinct hybrdization patern(DAN fingerprinting patterns) when the bacterial DNA were hybridized with randomly cloned 4.7 - kb DNA probe. The frequency of the genotypic distribution demonstrated that type C was the most prevalent genotype, the next being D, NT, A, B, and E in the descending order. The most prevalent serotype was serotype c, the next being a, nd, and b in the descending order. It was noted that the one serotype can represent more than two different genotypes and that multiple genotypic variants can also exist in the periodontal pockets within the sam subject.

• KSBB Journal
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• v.6 no.3
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• pp.223-230
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• 1991

Using the shuttle vector pECCGl between Escherichia coli and Corynebacterium glutamicum and C. glutamicum strain JS231 grown in the medium supplemented with penicillin-G, which inhibits the formation of cross-links in the peptidoglycan of bacterial cell wall, various parameters involved in electroporation system including resistance, electric field strength, capacitance, DNA concentration, and cell density were investigated independently and optimized for the high efficiency transformation of coryneform bacteria. Using cells grown with 0.3U/ml of penicillin-G and harvested at A600 of 0.7-0.8, transformation efficiencies of 107-l08 transformants/$\mu\textrm{g}$ of DNA with Corynebcctertum glutamicum strain JS231 and wild type ATCC13032 were achieved under conditions of 12.5kV/cm of electric field strength, 400 ohms of resistance, $25\mu$F of capacitance, 3$\times$108 cells per transformation(1.2$\times$1010 cells/ml) and 100ng of plasmid DNA per transformation.

• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.100-107
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• 1999

Apoptosis is now widely recognized as a common form of cell death and represents mechanism of cell clearance in many physiological situations where deletion of cells is required. In vivo administration of bacterial lipopolysaccharide (LPS) to Balb/c mice induced DNA fragmentation in the thymus. DNA fragmentation in the thymus was roughly dependent on the dose of LPS injected and reached the peak 18 hours after injection. This apoptosis in the thymus might be mediated due to LPS stimulant. DEN (diethylnitrosamine) has been shown to cause liver cancer in experimental animals and humans. The hepatic tumorigenesis was induced by ad libitum feeding of DEN only. It was suggested that DEN induced hepatic tumorgenesis in rat is a good reproducible model for studying biochemical and pathophysiological changes associated with the development of hepatic tumorigenesis and apoptosis.

• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.387-393
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• 2000

The process by which Agrobacterium tumefaciens genetically transforms plants involves a complex series of reactions communicated between the pathogen and the plants. To identify plant factors involved in agrobacterium-mediated plant transformation, a large number of T-DNA inserted Arabidopsis thaliana mutant lines were investigated for susceptibility to Agrobacterium infection by using an in vitro root inoculation assay. Based on the phenotype of tumorigenesis, twelve T-DNA inserted Arabidopsis mutants(rat) that were resistant to Agrobacterium transformation were found. Three mutants, rat1, rat3, and rat4 were characterized in detail. They showed low transient GUS activity and very low stable transformation efficiency compared to the wild-type plant. The resistance phenotype of rat1 and rats resulted from decreased attachment of Agrobacterium tumefaciens to inoculated root explants. They may be deficient in plant actors that are necessary for bacterial attachment to plant cells. The disrupted genes in rat1, rat3, and rat4 mutants were coding a arabinogalactan protein, a likely cell wall protein and a cellulose synthase-like protein, respectively.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1472-1476
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• 2006

Previous study demonstrated that the restriction barrier of Streptomyces griseus is almost completely bypassed by the Streptomyces-E. coli shuttle vectors passed through the E. coli GM161 strain and methylated with AluI and HpaII methyltransferases. The same DNA methylation of the genomic DNA fragments cloned the nonreplicative vectors generated integrative transformation and gene disruption of their chromosomal counterparts at high efficiencies in S. griseus. This result indicated that the efficiency of gene disruption depends on the efficient transfer of the incoming DNA into bacterial hosts.

• Journal of Species Research
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• v.10 no.4
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• pp.356-363
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• 2021

Heterotrophic nanoflagellates (HNFs, 2-20 ㎛ in size) are substantially capable of controlling bacterial abundance in aquatic environments, and microbial taxonomists have studied ecologically important and abundant HNFs for a long time. However, the classifications of HNFs have rarely been reported in Korea on the basis of morphology and 18S rDNA sequencing. Here, previously reported five HNFs from non-Korean habitats were isolated from Korean coastal seawater or intertidal sediments for the first time. Light microscopic observations and 18S rDNA phylogenetic trees revealed that the five isolated species were Cafeteria burkhardae strain PH003, Cafeteria graefeae strain UL001, Aplanochytrium minuta (formerly Labyrinthuloides minuta) strain PH004, Neobodo curvifilus strain KM017 (formerly Procryptobia sorokini), and Ancyromonas micra (formerly Planomonas micra) strain IG005. Being morphologically and phylogenetically indistinct from its closest species, all isolates from Korea were therefore regarded as identical species detected in other countries. Thus, this result indicates an expansion of known habitats that range from those of the five isolates in natural ecosystems on Earth.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.91-97
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• 1999

In this work, a 1.9-kb region of enterococcal plasmid p703/5 was isolated and the nucleotide sequence analysis of the region was performed. One major open reading frame (ORF) was identified encoding a polypeptide of 28 kDa. Database comparisons suggested that the protein showed some homology with other bacterial RepA proteins. Upstream of the ORF, a potential dnaA box, AT-rich region and 22-bp tandemly repeated sequences (DNA iterons), a feature typical for many replication ori sites, were recognized. Deletion analysis using Exonuclease III and several restriction enzymes indicated that the three elements and the gene product from the ORF were essential for replication and that the minimum unit of DNA required for replication resided on the 1.2-kb AvaII subfragment. Thus, this gene product was referred to as RepA.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.484-490
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• 2005

Human ribosomal protein S3 (rpS3), which has a DNA repair endonuclease activity, is a multifunctional protein. This protein is involved in DNA repair, translation, and apoptosis. In particular, rpS3 has a lyase activity, which cleaves the phosphodiester bond of damaged sites such as cyclobutane pyrimidine dimers and AP sites. Here, using deletion analysis, we identified that the repair endonuclease domain resides in the C-terminal region (165-243 aa) of rpS3. We also found that ectopic expression of GST-rpS3 in bacterial strain BL21 promoted the resistance of these cells to ultraviolet (UV) radiation and hydrogen peroxide ($H_{2}O_{2}$) treatment. The repair domain of rpS3 was sufficient to exhibit the resistance to UV irradiation and recover cell growth and viability, showing that the repair activity of rpS3 is responsible for the resistance to UV irradiation. Our study suggests that rpS3 is able to process DNA damage in bacteria via its repair domain, showing the resistance to genotoxic stress. This implies that rpS3-like activity could be operative in bacteria.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.193-201
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) are major causes of hospital- and community-acquired infections. The treatment of biofilm-related infections caused by these bacteria is a global healthcare challenge. Therefore, the development of alternative therapeutics is required. An essential oil extracted from Curcuma zedoaria (CZ) Rosc, also known as white turmeric, has been reported to possess various antimicrobial activities. In the present study, we evaluated the antibiofilm activities of an ethanolic extract of the CZ rhizome against MRSA and MSSA. The results showed that the CZ extract with the highest sub-minimum inhibitory concentration (sub-MIC), 1/2 MIC (0.312 mg/ml), significantly inhibited biofilm production by up to 80-90% in both tested strains. Subsequently, we evaluated the ability of the CZ extract to prevent cell-surface attachment to a 96-well plate and extracellular DNA (eDNA) release from the biofilm. The CZ extract demonstrated an inhibitory effect on bacterial attachment and eDNA release from the biofilm biomass. The CZ extract may inhibit biofilm formation by preventing eDNA release and cell-surface attachment. Therefore, this CZ extract is a potential candidate for the development of alternative treatments for biofilm-associated MRSA and MSSA infections.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.449-465
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• 2023

Plants are challenged by various pathogens throughout their lives, such as bacteria, viruses, fungi, and insects; consequently, they have evolved several defense mechanisms. In addition, plants have developed localized and systematic immune responses due to biotic and abiotic stress exposure. Animals are known to activate DNA damage responses (DDRs) and DNA damage sensor immune signals in response to stress, and the process is well studied in animal systems. However, the links between stress perception and immune response through DDRs remain largely unknown in plants. To determine whether DDRs induce plant resistance to pathogens, Arabidopsis plants were treated with bleomycin, a DNA damage-inducing agent, and the replication levels of viral pathogens and growth of bacterial pathogens were determined. We observed that DDR-mediated resistance was specifically activated against viral pathogens, including turnip crinkle virus (TCV). DDR increased the expression level of pathogenesis-related (PR) genes and the total salicylic acid (SA) content and promoted mitogen-activated protein kinase signaling cascades, including the WRKY signaling pathway in Arabidopsis. Transcriptome analysis further revealed that defense-and SA-related genes were upregulated by DDR. The atm-2atr-2 double mutants were susceptible to TCV, indicating that the main DDR signaling pathway sensors play an important role in plant immune responses. In conclusion, DDRs activated basal immune responses to viral pathogens.