• Journal of Microbiology
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• 제38권4호
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• pp.245-249
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• 2000

Catabolic pathways for the degradation of various aromatics by Sphingomonas yanoikuyae Bl are intertwined, joining at the level of substituted benzoates, which are further degraded vita ring cleavage reactions. The mutant strain EK497, which was constructed by deleting a large DNA region containing most of the genes for biphenyl, naphthalene, m-xylene, and m-toluate degradation, was unable to grow on all of the aromatics tested except for benzoate as the sole source of carbon and energy.S. yanoikuyae EK497 was found to possess only catechol ortho-ring cleavage activity due to deletion of the genes for the meta-cleavage pathway. Wild-type S. yanoikuyae Bl grown on benzoate has both catechol orthoand meta-cleavage activity. However, m-xylene and m-toluate, which are metabolized through methylbenzoate, and biphenyl, which is metabolized through benzoate, induce only the meta-cleavage pathway, suggesting the presence of a substrate-dependent induction mechanism.

• 한국가축번식학회지
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• 제15권2호
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• pp.125-132
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• 1991

The studies on the carried out to investigate the effects of capacitation method of spermatozoa on the in vitro fertilization and cleavage rate of bovine follicular oocytes. The ovaries were obtained from slaughtered Korean native cows. The follicular oocytes surrounded with cumulus cells were recovered by aspirating follicular fluids from the visible of diameter 3~5mm. The follicular oocytes were cultured in TCM-199 medium containing hormones and FCS for 24~48hrs in an incubator with 5% CO2 in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 12~18hrs with motile capacitated sperm by preincubation of mKRB, treatment of HIS(high strength ion), Ca-IA(Inophore A), BFF(bovine follicular fluids) and heparin. The results obtained in these experiments were summarized as follows : 1. The in vitro fertilizatin and cleavage rate offollicular oocytes fertilized with capacitated spermatozoas in BO solution by preincubation of mKRB, treatment of HIS, Ca-IA, BFF and heparin method were 53.1%, 33.9%, 50.8%, 48.1%, 58.8% and 28.1%, 17.7%, 26.2%, 22.8%, 32.8%, respectively. And the fertilization and cleavage rate of heparin method was of highest of all. 2. The in vitro fertilization and cleavage rate of follicular oocytes fertilized with capacitated spermatozoas in BO solutin by both caffeine, BSA and heparin methods were 65.8%, 70.3% and 40.8%, 47.3%, respectively, and those rates were higher treatment of heparin＋BSA, heparin＋caffeine than treatment of heparin. 3. The in vitro fertilization and cleavage rate of follicular oocytes fertilized with capacitated spermatozoa in BO solution with heparin concentrations of 2, 5, 10, 20, 40$\mu\textrm{g}$/ml were 50.0%, 54.7%, 58.1%, 51.7% and 27.9%, 32.8%, 37.1%, 30.0%, respectively. And the fertilization and cleavage rate of follicular oocytes fertilized with capacitated spermatozoas in BO solution with 10$\mu\textrm{g}$/ml of heparin was the highest of all. 4. The in vitro fertilization and cleavage rate of follicular oocytes fertilized with capacitated spermatozoas in BO solution containing heparin with caffeine concentraton of 10, 20, 30, 40$\mu\textrm{g}$/ml were 71.4%, 74.3% and 70.6%, 70.0% and 45.7%, 47.3%, 44.1%, 41.4%, respectively. The fertilization and cleavage rate of spermatozoa fertilized in BO solution with caffeine and heparin together(70.3~74.3%) was higher than that of spermatozoa fertilized in BO solution with heparin(58.8%). 5. The in vitro fertilization and cleavage rate of follicular oocytes fertilized with capacitated spermatozoas in BO solution containing heparin with BSA concentration of 5, 10, 20, 30$\mu\textrm{g}$/ml were 63.6%, 62.9%, 66.7%, 60.3% and 44.1%, 43.5%, 48.5%, 42.7%, respectively. The fertilization and cleavage rate of spermatozoa fertilized in BO solution with BSA and heparin together(60.3~66.73%) was higher than that of spermatozoa fertilized in BO solution with heparin(58.8%).

• Journal of Animal Science and Technology
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• 제57권8호
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• pp.27.1-27.6
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• 2015

This study was designed to investigate the effects of ${\alpha}$-tocopherol and granulosa cells monolayer on nuclear maturation and cleavage rates of ovine cumulus-oocyte complexes (COCs). The COCs (n = 2814) were matured in maturation medium supplemented with various concentration of ${\alpha}$-tocopherol (0, 5, 10, $15{\mu}g/ml$), oocytes were incubated at $39^{\circ}C$ with 5 % $CO_2$ for 24 h in three culture systems: (a) maturation medium (MM; n = 884), (b) co-cultured with granulosa cells (CG; n = 982) and (c) co-cultured with granulosa cells and cells were further cultured in MM for 12 h (CG + 12hMM; n = 948). Our results showed that ${\alpha}$-tocopherol had no effect on GVBD and MII as compared to control group, but when ${\alpha}$-tocopherol added to maturation medium the rate of cleavage decreased. This indicates interaction of above mentioned factors in any of the treatments showed no significant differences on the rate of maturation and cleavage stages (MII, GVBD and cleavage) (p > 0.05). The oocytes co-cultured with granulosa cells for 24 h had beneficial effects on cleavage rate. The maximum MII and cleavage rates were achieved when oocytes had extra 12 h culture in the maturation medium without granulosa cells. Results also showed our modified co-culture system (CG + 12hMM), improved rates of MII and the cleavage in comparison with other studied maturation systems.

• Clinical and Experimental Reproductive Medicine
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• 제47권4호
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• pp.293-299
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• 2020

Objective: The goal of the present study was to investigate the rate of chromosomal aneuploidies in surplus embryos after sex determination at the cleavage stage. Then, the same chromosomal aneuploidies were evaluated in blastocysts after extended culture. Methods: Sixty-eight surplus embryos were biopsied at the cleavage stage and incubated for an additional 3 days to allow them to reach the blastocyst stage. The embryos were reanalyzed via fluorescence in situ hybridization (FISH) to examine eight chromosomes (13, 15, 16, 18, 21, 22, X, and Y) in both cleavage-stage embryos and blastocysts. Results: Although the total abnormality rate was lower in blastocysts (32.35%) than in cleavage-stage embryos (45.58%), the difference was not significant (p=0.113). However, when we restricted the analysis to autosomal abnormalities, we observed a significant difference in the abnormality rate between the cleavage-stage embryos (44.11%) and the blastocysts (17.64%, p=0.008). A higher rate of sex chromosomal abnormalities was also observed in cleavage-stage embryos (29.4%) than in blastocysts (14.70%, p=0.038). Conclusion: The data indicated that embryo biopsy should be conducted at the blastocyst stage rather than the cleavage stage. The results also emphasized that examination of common chromosomal aneuploidies apart from sex selection cycles can be conducted in the blastocyst stage with the FISH method.

• Molecules and Cells
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• 제26권3호
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• pp.308-313
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• 2008

In animals, microRNAs (miRNAs) and small interfering RNAs (siRNAs) repress expression of protein coding genes by assembling distinct RNA-induced silencing complexes (RISCs). It has previously been shown that passenger-strand cleavage is the predominant mechanism when siRNA duplexes are loaded into Argonaute2 (Ago2)-containing RISC, while an unwinding bypass mechanism is favored for miRNA duplexes with mismatches. Here I present experimental data indicating that some mammalian miRNAs are assembled into Ago2-containing RISC by cleaving their corresponding miRNA star strands. This phenomenon may depend on the secondary structure near the scissile phosphate of the miRNA duplex. In addition, I show that ATP is not required for star-strand cleavage in this process. Taken together, the data here provide insight into the miRNA-loading mechanisms in mammals.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (B)
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• pp.247-249
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• 2005

Cleavage Site 분석 및 예측은 바이러스 증식에 필요한 핵심 단백질인 Protease$(3CL^{pro})$를 예측하게 하고, 예측한 Protease의 활성을 억제함으로써 바이러스 중식을 저지하게 된다. 본 연구에서는 신경망과 결정트리, 유전자 알고리즘을 이용하여 SARS-CoV의 cleavage site를 분석하고, 학습 결과에서 추출된 규칙(Rule)에 의해 cleavage site를 예측한다. 또한 신경망에서 학습된 지식(Knowledge)을 이용하여 유전자 알고리즘의 성능을 향상시키는 지식기반 유전자 알고리즘 (KBGA: Knowledge-Based Genetic Algorithm)을 제안한다.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1137-1140
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• 2008

M1 RNA, the catalytic subunit of Escherichia coli RNase P, is an essential ribozyme that processes the 5' leader sequence of tRNA precursors (ptRNAs). Using KS2003, an E. coli strain generating only low levels of M1 RNA, which showed growth defects, we examined whether M1 RNA is involved in polycistronic mRNA processing or degradation. Microarray analysis of total RNA from KS2003 revealed six polycistronic operon mRNAs (acpP-fabF, cysDNC, flgAMN, lepAB, phoPQ, and puuCBE) showing large differences in expression between the adjacent genes in the same mRNA transcript compared with the KS2001 wild type strain. Model substrates spanning an adjacent pair of genes for each polycistronic mRNA were tested for RNase P cleavage in vitro. Five model RNAs (cysNC, flgMN, lepAB, phoPQ, and puuBE) were cleaved by RNase P holoenzyme but not by M1 RNA alone. However, the cleavages occurred at non-ptRNA-like cleavage sites, with much less efficiency than the cleavage of ptRNA. Since cleavage products generated by RNase P from a polycistronic mRNA can have different in vivo stabilities, our results suggest that RNase P cleavage may lead to differential expression of each cistron.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.964-972
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• 2011

This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1290-1296
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• 2012

Fenton reaction and iron autoxidation have been debated for the major process in ROS mediated DNA cleavage. We compared both processes on iron oxidation, DNA cleavage, and cyclic voltammetric experiment at different pHs. Both oxidation reactions were preferred at basic pH condition, unlike DNA cleavage. This indicates that iron oxidation and the following steps probably occur separately. The ROS generated from autoxidation seems to be superoxide radical since sod exerted the best inhibition on DNA cleavage when $H_2O_2$ was absent. In comparison of cyclic voltammograms of $Fe^{2+}$ in NaCl solution and phosphate buffer, DNA addition to phosphate buffer induced significant change in the redox cycle of iron, indicating that iron may bind DNA as a complex with phosphate. Different pulse voltammogram in the presence of ctDNA suggest that iron ions are recyclable at acidic pH, whereas they may form an electrically stable complex with DNA at high pH condition.

• Bulletin of the Korean Chemical Society
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• 제17권4호
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• pp.353-357
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• 1996

Second-order rate constants have been measured spectrophotometrically for the reaction of 2,4-dinitrophenyl X-substituted benzenesulfonates with Z-substituted phenoxides in absolute ethanol at 25.0±0.1 ℃. The nucleophilic substitution reaction gives both S-O bond and C-O bond cleavage products. The extent of S-O bond cleavage increases significantly with increasing electron withdrawing ability of the sulfonyl substitutent X, while that of the C-O bond cleavage is independent on the electronic effect of the substituent. On the contratry, the effect of the substituent Z in the nucleophilic phenoxide is more significant for the C-O bond cleavage than for the S-O bond cleavage. Aminolyses of 2,4-dinitrophenyl benzenesulfonate (1) with various 1°, 2° and 3°amines have revealed that steric effect is little important. The extent of S-O bond cleavage increases with increasing the basicity of the amines, but decreases with increasing the basicity of the nucleophilic aryloxides, indicating that the HSAB principle is not always operative. Besides, reactant and solvent polarizability effect has also been found to be an important factor in some cases but not always to influence the reaction site.