• Journal of Life Science
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• v.16 no.1
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• pp.131-135
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• 2006

Oligopeptide is known to be an essential nitrogen nutrient for bacterial growth. Oligopeptide can be transported into cytoplasm by a specific transport system, Opp system. Opp system is composed of five proteins, which are transcribed by an operon. These are responsible for oligopeptide binding protein (OppA), permease (OppB and OppC) and energy generation system (OppD and OppF), respectively. Previously, we isolated the opp operon from Vibrio fluvialis and constructed the oppA mutant by allelic exchange method. In this study, we investigated the growth pattern and biofilm production under the different growth condition. When the cells were cultivated using brain heart infusion(BHI) medium, the wild type was faster than the mutant in growth during the exponential phase. However, it showed that the growth pattern of two strains in M9 medium is very similar. The growth of wild type showed better than that of the mutant grown at pH 8. At pH 7, there was no an obvious difference in growth. After 5 mM $H_2O_2$ was treated to the cells $(OD_{600}=1.2)$, the cell survival was examined. The oppA mutation did not affect in survivability. In the presence of $10{\mu}g/ml$ polymyxin B, the biofilm production of the oppA mutant was higher than that of the wild type.

• Radiation Oncology Journal
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• v.24 no.1
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• pp.30-36
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• 2006

Purpose: It is well known from clinical experience that acute complications of chemoradiation therapy vary from patients to patients. However, there are no known factors to predict these acute complications before treatment starts. The human XRCC1 gene is known as a DNA base excision repair gene. We investigated the possibilities of XRCC1 gene polymorphisms as a predictor for the acute complications of chemoradiation therapy in colorectal cancer patients. Materials and Methods: From July 1997 to June 2003, 86 colorectal cancer patients (71 rectal cancer, 13 sigmoid colon cancer and 2 colon cancer patients) were treated with chemoradiation therapy at the Department of Radiation Oncology, Inha University Hospital. Twenty-two patients were in stage B, 50 were in stage C, 8 were in stage D and 6 patients were unresectable cases. External radiation therapy was delivered with 10MV X-ray at a 1.8 Gy fraction per day for a total dose of radiation of $30.6{\sim}59.4 Gy$ (median: 54 Gy). All the patients received 5-FU based chemotherapy regimen. We analyzed the acute complications of upper and lower gastrointestinal tract based on the RTOG complication scale. The initial and lowest WBC and platelet count were recorded during both the RT period and the whole treatment period. Allelic variants of the XRCC1 gene at codons 194, 280 and 399 were analyzed in the lymphocyte DNA by performing PCR-RFLP. Statistical analyses were carried out with the SAS (version 6.12) statistical package. Results: When all the variables were assessed on the multivariate analysis, recurrent disease revealed the factors that significantly correlated with upper gastrointestinal acute complications. Arg399Gln polymorph isms of the XRCC1 gene, the radiation dose and the frequencies of chemotherapy during radiation therapy were significantly correlated with lower gastrointestinal complications. Arg399Gln polymorph isms also affected the decrease of the WBC and platelet count during radiation therapy. Conclusion: Although the present sample size was too small for fully evaluating this hypothesis, this study suggests that Arg399Gln polymorph isms of the XRCC1 genes may be used as one of the predictors for acute complications of chemoradiation therapy in colorectal cancer patients.

• Journal of Yeungnam Medical Science
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• v.22 no.2
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• pp.166-182
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• 2005

Background: Cyclin-dependent kinase (CDK) inhibitors are family of molecules that regulate the cell cycle. The CDKN2, a CDK4 inhibitor, also called p16, has been implicated in human tumorigenesis. The CDKN2 inhibits the cyclin/CDK complexes which regulate the transition from G1 to S phase of cell cycle. There is a previous report that homozygous deletion of CDKN2 region on chromosome 9p21 was detected frequently in astrocytoma, glioma and osteosarcoma, less frequently in lung cancer, leukemia and ovarian cancer, but not detected in colon cancer and neuroblastoma. However, little is known about the relationship between CDKN2 and laryngeal cancer. Therefore this study was initiated to investigate the role of CDKN2 in human laryngeal squamous cell carcinoma development.1) Materials and methods: We used 5 human laryngeal carcinoma cell lines whether they have deletions or losses of CDKN2 gene expression by DNA-PCR or RT-PCR, respectively. We examined 8 fresh frozen human laryngeal cancer tissues to detect the loss of heterozygosity (LOH) of CDKN2. PCR was performed by using microsatellite markers of short arm of human chromosome 9 (D9S126, D9S144, D9S156, D9S161, D9S162, D9S166, D9S171, D9S200 and D9SIFNA). For informative cases, allelic loss was scored if the signal of one allele was significantly decreased in tumor DNA when compared to the same allele in normal DNA. Results: The CDKN2 DNA deletion was observed in 3 cell lines. The CDKN2 mRNA expression was observed in only one cell line, which was very weak. LOH was detected in 7 cases (87.5%). Conclusion: These results suggest that CDKN2 plays a role in the carcinogenesis of human laryngeal squamous cell carcinoma.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.325-334
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• 2023

The invasive red swamp crayfish, Procambarus clarkii, is native to south-central United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.