• Journal of Microbiology
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• 제44권6호
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• pp.641-648
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• 2006

We previously reported that Skp1, a component of the Skp1-Cullin-F-box protein (SCF) complex essential for the timely degradation of cell cycle proteins by ubiquitination, physically interacts with Bfa1, which is a key negative regulator of the mitotic exit network (MEN) in response to diverse checkpoint-activating stresses in budding yeast. In this study, we initially investigated whether the interaction of Skp1 and Bfa1 is involved in the regulation of the Bfa1 protein level during the cell cycle, especially by mediating its degradation. However, the profile of the Bfa1 protein did not change during the cell cycle in skp1-11, which is a SKP1 mutant allele in which the function of Skp1 as a part of SCF is completely impaired, thus indicating that Skp1 does not affect the degradation of Bfa1. On the other hand, we found that the skp1-12 mutant allele, previously reported to block G2-M transition, showed defects in mitotic exit and cytokinesis. The skp1-12 mutant allele also revealed a specific genetic interaction with ${\Delta}bfa1$. Bfa1 interacted with Skp1 via its 184 C-terminal residues (Bfa1-D8) that are responsible for its function in mitotic exit. In addition, the interaction between Bfa1 and the Skp1-12 mutant protein was stronger than that of Bfa1 and the wild type Skp1. We suggest a novel function of Skp1 in mitotic exit and cytokinesis, independent of its function as a part of the SCF complex. The interaction of Skp1 and Bfa1 may contribute to the function of Skp1 in the mitotic exit.

• 대한한의학회지
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• 제23권3호
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• pp.188-199
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• 2002

Objectives : Banhasasim-tang has been clinically used to treat upper gastric intestinal discomfort. The object of this study is to examine the defense effect of Banhasasim-tang for acute duodenal injury of the mouse. Methods and Materials : Twenty-one rats were divided into 3 groups and treated as follows: the control group was untreated mice. The ADE group was acute duodenal-damage-elicited mice. The BST group was Banhasasim-tang treated mice before acute duodenal damage elicitation. The groups were examined with common morphology, paneth cells in intestinal crypt, absorptive cells and goblet cells in epithelium, cell division in mucose, COX-l as mucosal protector, COX-2 (which appears to play an important role in inflammation), IL-2R-inducing cellular immuno-chainreaction, and the distribution of apoptotic cells. Results : 1. Common morphology: the ADE group was observed with duodenal injury - loss of villi, infiltration of cells concerned to inflammation (lymphocytes, granular leukocytes) to submucosal layer - by hemorrhagic erosions, while the BST group was seen the same as normal in proportion to increasing treatment time before injury. 2. Histochemical change: the ADE group was observed with noticeable decreased distribution of absorptive cells with microvilli, acid mucin secreted goblet cell, neutral mucin secreted goblet cell, paneth cells compared to the normal group. The BST group was seen to have distribution of epithelium cells resembling normal in proportion to increasing treatment time before injury. 3. Imnunohistochemical change: the ADE group showed a change of factors leading to duodenal injury as reduce of cytokinesis, COX-1, increase of COX-2, IL-2R-. In contrast, the BST group tended to reduction of cytokinesis, COX-1, increase of COX-2, IL-2R- in proportion to increasing taking time before injury. 4. Apoptosis change: the ADE group showed increasing apoptosis cells, in contrast to the BST group which was the same as normal in proportion to increasing treatment time before injury. Conclusions : According to the above results, by increasing the defense system of mucosal epithelium, Banhasasim-tang is thought to effectively protect tissue against ulcers resulting from acute duodenal injury.

• Molecules and Cells
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• 제39권11호
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• pp.814-820
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• 2016

FtsZ, a tubulin homologue, is an essential protein of the Z-ring assembly in bacterial cell division. It consists of two domains, the N-terminal and C-terminal core domains, and has a conserved C-terminal tail region. Lateral interactions between FtsZ protofilaments and several Z-ring associated proteins (Zaps) are necessary for modulating Z-ring formation. ZapD, one of the positive regulators of Z-ring assembly, directly binds to the C-terminal tail of FtsZ and promotes stable Z-ring formation during cytokinesis. To gain structural and functional insights into how ZapD interacts with the C-terminal tail of FtsZ, we solved two crystal structures of ZapD proteins from Salmonella typhimurium (StZapD) and Escherichia coli (EcZapD) at a 2.6 and $3.1{\AA}$ resolution, respectively. Several conserved residues are clustered on the concave sides of the StZapD and EcZapD dimers, the suggested FtsZ binding site. Modeled structures of EcZapD-EcFtsZ and subsequent binding studies using bio-layer interferometry also identified the EcFtsZ binding site on EcZapD. The structural insights and the results of bio-layer interferometry assays suggest that the two FtsZ binding sites of ZapD dimer might be responsible for the binding of ZapD dimer to two protofilaments to hold them together.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6955-6960
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• 2014

Background: The cytokinesis-block micronucleus (CBMN) assay is a standard cytogenetic tool employed to evaluate chromosomal damage subsequent to pesticide exposure. Objectives: To evaluate the pooled levels of total micronuclei (MN) and binucleated cells with micronuclei (MNC) in 1000 binucleated lymphocytes among population occupationally exposed to pesticides and further determine the more sensitive biomarker of CBMN. Materials and Methods: A meta-analysis on the pooled levels of MN and MNC in binucleated lymphocytes among occupationally pesticide-exposed populations was conducted using STATA 10.0 software and Review Manager 5.0.24 in this study. Results: We found significant differences in frequencies of MN and MNC in 1000 binucleated lymphocytes between pesticide-exposed groups and controls, and the summary estimates of weighted mean difference were 6.82 [95% confidence interval (95% CI): 4.86-8.78] and 5.08 (95% CI: 2.93-7.23), respectively. However, when we conducted sensitivity analyses further, only the MN remained statistically different, but not the MNC, the summary estimates of weight mean difference were 2.86 (95% CI: 2.51-3.21) and 0.50 (95% CI: -0.16-1.17), respectively. We also observed pesticide-exposed subjects had significantly higher MN frequencies than controls among smokers and nonsmokers, male and female populations, and American, Asian and European countries in stratified analyses. Conclusions: The frequency of MN in peripheral blood lymphocytes might be a more sensitive indicator of early genetic effects than MNC using the CBMN assay for occupationally pesticide-exposed populations.

• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.1010-1022
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• 2017

Hybrid histidine kinase is part of a two-component system that is required for various stress responses and pathogenesis of pathogenic fungi. The Tco1 gene in human pathogen Cryptococcus neoformans encodes a hybrid histidine kinase and is important for pathogenesis. In this study, we identified a Tco1 homolog, UmTco1, in the maize pathogen Ustilago maydis by bioinformatics analysis. To explore the role of UmTco1 in the survival of U. maydis under environmental stresses and its pathogenesis, ${\Delta}umtco1$ mutants were constructed by allelic exchange. The growth of ${\Delta}umtco1$ mutants was significantly impaired when they were cultured under hyperosmotic stress. The ${\Delta}umtco1$ mutants exhibited increased resistance to antifungal agent fludioxonil. In particular, the ${\Delta}umtco1$ mutants were unable to produce cytokinesis or conjugation tubes, and to develop fuzzy filaments, resulting in impaired mating between compatible strains. The expression levels of Prf1, Pra1, and Mfa1, which are involved in the pheromone pathway, were significantly decreased in the ${\Delta}umtco1$ mutants. In inoculation tests to the host plant, the ${\Delta}umtco1$ mutants showed significantly reduced ability in the production of anthocyanin pigments and tumor development on maize leaves. Overall, the combined results indicated that UmTco1 plays important roles in the survival under hyperosmotic stress, and contributes to cytokinesis, sexual development, and virulence of U. maydis by regulating the expression of the genes involved in the pheromone pathway.

• 대한예방한의학회지
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• 제12권2호
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• pp.51-59
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• 2008

Objectives : Buplueri Radix (BR), used medical plant in Korea traditional medicine, contains various compounds, including a series of triterpene saponins known as saikosaponins. We performed this study for the protective effect of BR against oxidative damage induced by 1,2,4-benzentriol(BT) in human lymphocytes. Methods : In order to investigate the protective effect of BR against carcinogens, genotoxicity induced by benzene metabolite, BT were performed using cytokinesis-block micronucleus(CBMN) assay and comet assay. Results : The frequency of micronucleus at 25, 50 and $100{\mu}M$ concentration of BT were $8{\pm}2.36$, $23{\pm}2.31$, $35{\pm}4.17$ respectively. In addition of BR with concentration of 25 and $50{\mu}g/mL$, MN frequencies were significantly decreased. According to comet assay, BT induced DNA damage in a dose-dependent manner at concentration of 10 and 50 while BT with BR treatment decreased DNA breakage. No genotoxicity was observed by BR($25{\sim}50{\mu}g/mL$) treatment alone on DNA breakage. Since BT can induce DNA damage through the generation of reactive oxygen species(ROS), we examined the level of ROS in human lymphocytes treated with BT and/or BR using DCF-DA, ROS-sensitive probe. The generation of ROS in BT-treated cells was also observed, and BR addition inhibited the level of BT-induced DNA damage. Conclusions : From above results it is suggested that BR could protect the cell and DNA from pro-oxidant effect by ROS by BT

• Toxicological Research
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• 제6권1호
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• pp.29-40
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• 1990

Cytotoxic effects of cytosine arabinoside and vinblastine on cultured fibroblasts were determined by colorimetric assays of neutral red (NR) and tetrazolium MTT, and by mutagenicity tests . Cytosine arabinoside and vinblastine were highly toxic by showing that concentrations of NR-50 and MTT-50 of two drugs were lower than 100 ${\mu}$M. At mid-point cytotoxicityvalue of two drugs, frequencies of micronuclei and SCEs were very high and chromosome showed structural abnormalities. The sizes of micronuclei formed by vinblastine were larger than those induced by cytosine arabinoside. These results suggest that cytosine arabinoside and vinblastine have highy mutagenic and severe cytotoxic effects on the cultured mouse fibroblasts.

• 대한수의학회지
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• 제36권2호
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• pp.277-281
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• 1996

A technique to improve the analysis of micronuclei(MN) in lymphocytes as a cytogenetic indicator is reported. For the purpose of diminishing the variation of the result from individual reader and making it easier to distinguish accurately a cytokinesis blicked(CB) lymphocyte and micronuclei, we tried a modified one-step silver staining technique as a method for detection of the argyrophilic nucleolar organizer region(AgNOR) with or without conventional Giemsa stain in the slide from CB method. Compared with the conventional Giemsa stain, the preparation processed with this method are especially useful for the accurate analysis of MN of cultured lymphocyte with cytochalasin B. This method will be a useful technique for automated calculation of MN.

• 한국임상수의학회지
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• 제21권3호
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• pp.286-290
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• 2004

Cytogenetic and hematological analysis was performed in peripheral blood of pig in the vicinity of Yeonggwang nuclear power station and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from pig was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 Gy to 4 Gy. MN rates in lymphocytes of pig from Yeonggwang nuclear power station and control area were 10.60/1,000 and 11.10/1,000, respectively. There were no significant differences in MN frequencies and hematological values in pig between Yeonggwang and control area. The study indicates that the MN assay in lymphocyte of pig is a rapid, sensitive and accurate method that can be used to monitor a large population exposed to radiation.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
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• pp.134-134
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• 2002

In order to investigate whether genetic polymorphisms in the mEH exon3 (Tyr139His), exon4 (His113Arg) interact with the formation of MN in benzene exposed workers, the PCR-RFLP based genotyping of 76 exposed and 115 controls were performed and cytokinesis-block micronucleus (CBMN) analysis of 56 exposed and 53 controls was employed.(omitted)