22 research outputs found

    Quick and affordable DNA cloning by reconstitution of Seamless Ligation Cloning Extract using defined factors

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    新しいDNAクローニング技術の開発 --京大学部生研究チームの発見が契機に--. 京都大学プレスリリース. 2023-05-17.The cloning of DNA fragments to plasmid vectors is at the heart of molecular biology. Recent developments have led to various methods utilizing homologous recombination of homology arms. Among them, Seamless Ligation Cloning Extract (SLiCE) is an affordable alternative solution that uses simple Escherichia coli lysates. However, the underlying molecular mechanisms remain unclear and the reconstitution of the extract by defined factors has not yet been reported. We herein show that the key factor in SLiCE is Exonuclease III (ExoIII), a double-strand (ds) DNA-dependent 3′-5′ exonuclease, encoded by XthA. SLiCE prepared from the xthAΔ strain is devoid of recombination activity, whereas purified ExoIII alone is sufficient to assemble two blunt-ended dsDNA fragments with homology arms. In contrast to SLiCE, ExoIII is unable to digest (or assemble) fragments with 3′ protruding ends; however, the addition of single-strand DNA-targeting Exonuclease T overcomes this issue. Through the combination of commercially available enzymes under optimized conditions, we achieved the efficient, reproducible, and affordable cocktail, “XE cocktail, ” for seamless DNA cloning. By reducing the cost and time required for DNA cloning, researchers will devote more resources to advanced studies and the careful validation of their own findings

    Ion-Exclusion/Cation-Exchange Chromatography Using Dual-Ion-Exchange Groups for Simultaneous Determination of Inorganic Ionic Nutrients in Fertilizer Solution Samples for the Management of Hydroponic Culture

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    In this study, ion-exclusion/cation-exchange chromatography (IEC/CEC) using dual-ion-exchange groups (carboxy and sulfo groups) for the simultaneous determination of anions (SO42−, Cl−, NO3−, and HPO42−) and cations (Na+, NH4+, K+, Mg2+, and Ca2+) was developed. By using the combination of dual-ion-exchange groups, simultaneous separation of inorganic ions with HPO42− was achieved that was impossible by the conventional IEC/CEC based on the single-ion-exchange group (carboxy group). This method was applied to the monitoring of inorganic ionic nutrients in fertilizer solution samples in hydroponic culture. As a result, a higher peak resolution of inorganic anions and cations with phosphate ion using IEC/CEC with dual-ion-exchange groups was achieved in the absence of matrix effects. In addition, the developed method helps to understand the behavior of ionic nutrients in fertilizer solution during hydroponic cultivation and is potentially useful for the individual fertilization of ionic nutrients

    Effect of celecoxib, a selective cyclooxygenase-2 inhibitor on carbon tetrachloride intoxication in rats.

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    CCl(4) (0.5 ml/kg as CCl(4)) was orally administered to rats. Twelve hours after administration of CCl(4), plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, indicators of liver necrosis, were significantly higher than those in the control group showing that active liver necrosis took place. At the same time the level of liver vitamin C was decreased significantly compared to that in the control group. Oral administration of 100 mg/kg each of celecoxib 3 and 8 h after CCl(4) treatment did not change plasma ALT and AST and liver vitamin C levels 12 h after CCl(4) treatment, but 24 h after CCl(4) treatment, significantly decreased plasma ALT and AST levels and elevated liver vitamin C level. These finding suggested that celecoxib effectively ameliorated the necrotic action and the oxidative stress induced by CCl(4) in the second phase. Although the plasma levels of all ceramide species were significantly increased 24 h after CCl(4) intoxication, treatment with celecoxib significantly reduced the total ceramide concentration in plasma. These results indicated that celecoxib significantly ameliorated the toxicity of CCl(4) in the second phase.CCl(4) (0.5 ml/kg as CCl(4)) was orally administered to rats. Twelve hours after administration of CCl(4), plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, indicators of liver necrosis, were significantly higher than those in the control group showing that active liver necrosis took place. At the same time the level of liver vitamin C was decreased significantly compared to that in the control group. Oral administration of 100 mg/kg each of celecoxib 3 and 8 h after CCl(4) treatment did not change plasma ALT and AST and liver vitamin C levels 12 h after CCl(4) treatment, but 24 h after CCl(4) treatment, significantly decreased plasma ALT and AST levels and elevated liver vitamin C level. These finding suggested that celecoxib effectively ameliorated the necrotic action and the oxidative stress induced by CCl(4) in the second phase. Although the plasma levels of all ceramide species were significantly increased 24 h after CCl(4) intoxication, treatment with celecoxib significantly reduced the total ceramide concentration in plasma. These results indicated that celecoxib significantly ameliorated the toxicity of CCl(4) in the second phase

    The Detection of Candida Species in Patients with Halitosis

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    To examine the effects of Candida on halitosis, the carrier state of Candida was examined in patients who made a visit with a chief complaint of halitosis. Methods. Subjects were 123 patients (42 males and 81 females) who visited our clinic, with a chief complaint of halitosis. Their average age was 45.8 years. To examine halitosis, an organoleptic test was conducted, and volatile sulfur compounds (VSCs) were measured by gas chromatography. Tongue-coating samples collected at the initial visit were cultured in CHROMagar Candida medium. The results of a Candida culture test, an organoleptic test, and VSC measurements were examined. Results. The male-to-female ratio of the patients was about 1 : 2. Patients with severe halitosis accounted for less than 20%. In the Candida culture test, the positive rate was about 25.2%, and C. albicans was the most frequently detected. Two kinds of Candida species were detected in 75% (6/8) of the strongly Candida-positive group. The VSC measurements were correlated with the Candida culture test results. Methyl mercaptan concentration was higher in the strongly C. albicans-positive group or the subjects having two kinds of Candida species. Conclusion. We suggest that imbalance of oral microbial community exists in the strongly -positive group

    Specific markers and properties of synovial mesenchymal stem cells in the surface, stromal, and perivascular regions

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    Abstract Background Synovial mesenchymal stem cells (MSCs) are an attractive cell source for cartilage and meniscus regeneration. Synovial tissue can be histologically classified into three regions; surface, stromal and perivascular region, but the localization of synovial MSCs has not been fully investigated. We identified markers specific for each region, and compared properties of MSCs derived from each region in the synovium. Methods The intensity of immunostaining with 19 antibodies was examined for surface, stromal, and perivascular regions of human synovium from six osteoarthritis patients. Specific markers were identified and synovial cells derived from each region were sorted. Proliferation, surface marker expression, chondrogenesis, calcification and adipogenesis potentials were compared in synovial MSCs derived from the three regions. Results We selected CD55+ CD271− for synovial cells in the surface region, CD55− CD271− in the stromal region, and CD55− CD271+ in the perivascular region. The ratio of the sorted cells to non-hematopoietic lineage cells was 5% in the surface region, 70% in the stromal region and 15% in the perivascular region. Synovial cells in the perivascular fraction had the greatest proliferation potential. After expansion, surface marker expression profiles and adipogenesis potentials were similar but chondrogenic and calcification potentials were higher in synovial MSCs derived from the perivascular region than in those derived from the surface and stromal regions. Conclusions We identified specific markers to isolate synovial cells from the surface, stromal, and perivascular regions of the synovium. Synovial MSCs in the perivascular region had the highest proliferative and chondrogenic potentials among the three regions
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