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排序方式: 共有115条查询结果,搜索用时 15 毫秒
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Kurosawa K Bui VP VanEssendelft JL Willis LB Lessard PA Ghiviriga I Sambandan TG Rha CK Sinskey AJ 《Applied microbiology and biotechnology》2006,72(1):145-154
A new actinomycete strain designated MITKK-103 was isolated from the soil of a flowerpot using a humic acid agar medium. The newly isolated strain was able to produce a large amount of actinomycin X2 even under nonoptimized growing conditions and serves as a promising source of this antibiotic. Actinomycin X2 has higher cytotoxicity toward cultured human leukemia (HL-60) cells than does actinomycin D, and it induces cell death via apoptosis. A nearly complete 16S ribosomal DNA (rDNA) sequence from the isolate was determined and found to have high identity (98.5–100%) with Streptomyces galbus, Streptomyces griseofuscus, and Streptomyces padanus, indicating that MITKK-103 belongs to the genus Streptomyces. The isolate clustered with species belonging to the S. padanus clade in a 16S-rDNA-based phylogenetic tree and showed 75% overall homology to S. padanus ATCC 25646 in DNA–DNA relatedness analysis. Although the growth of the isolate was somewhat different from the three species mentioned, the strain MITKK-103 most closely resembles S. padanus on the basis of the morphological and phenotypic characteristics, phylogenetic analysis, and genotypic data. As such, this is the first report of a strain of S. padanus capable of producing actinomycins. 相似文献
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Background
Since the completion of the HapMap project, huge numbers of individual genotypes have been generated from many kinds of laboratories. The efforts of finding or interpreting genetic association between disease and SNPs/haplotypes have been on-going widely. So, the necessity of the capability to analyze huge data and diverse interpretation of the results are growing rapidly. 相似文献44.
Sebastian L. Riedel Christopher J. Brigham Charles F. Budde Johannes Bader ChoKyun Rha Ulf Stahl Anthony J. Sinskey 《Biotechnology and bioengineering》2013,110(2):461-470
Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA‐based products. In this work, a process was designed for effective recovery of the copolymer poly(hydroxybutyrate‐co‐hydroxyhexanoate) (P(HB‐co‐HHx)) containing high levels of HHx (>15 mol%) from Ralstonia eutropha biomass using non‐halogenated solvents. Several non‐halogenated solvents (methyl isobutyl ketone, methyl ethyl ketone, and butyl acetate and ethyl acetate) were found to effectively dissolve the polymer. Isoamyl alcohol was found to be not suitable for extraction of polymer. All PHA extractions were performed from both dry and wet cells at volumes ranging from 2 mL to 3 L using a PHA to solvent ratio of 2% (w/v). Ethyl acetate showed both high recovery levels and high product purities (up to 99%) when using dry cells as starting material. Recovery from wet cells, however, eliminates a biomass drying step during the downstream process, potentially saving time and cost. When wet cells were used, methyl isobutyl ketone (MIBK) was shown to be the most favorable solvent for PHA recovery. Purities of up to 99% and total recovery yields of up to 84% from wet cells were reached. During polymer recovery with either MIBK or butyl acetate, fractionation of the extracted PHA occurred, based on the HHx content of the polymer. PHA with higher HHx content (17–30 mol%) remained completely in solution, while polymer with a lower HHx content (11–16 mol%) formed a gel‐like phase. All PHA in solution could be precipitated by addition of threefold volumes of n‐hexane or n‐heptane to unfiltered PHA solutions. Effective recycling of the solvents in this system is predicted due to the large differences in the boiling points between solvent and precipitant. Our findings show that two non‐halogenated solvents are good candidates to replace halogenated solvents like chloroform for recovery of high quality PHA. Biotechnol. Bioeng. 2013; 110: 461–470. © 2012 Wiley Periodicals, Inc. 相似文献
45.
Yeona Cho Jee Suk Chang Koon Ho Rha Sung Joon Hong Young Deuk Choi Won Sik Ham Jun Won Kim Jaeho Cho 《PloS one》2016,11(1)
Purpose/Objectives
Treatment of the primary tumor reportedly improves survival in several types of metastatic cancer. We herein evaluated the efficacy and toxicity of radiotherapy for the primary tumor in prostate cancer with metastasis.Materials/Methods
The study cohort included 140 men with metastatic prostate cancer at initial diagnosis. Metastatic sites were divided into 4 groups as follows: solitary bone, 2–4 bones, ≥5 bones, and visceral organs. Patient, tumor, and treatment characteristics, and clinical outcomes were compared between patients treated with (prostate radiotherapy [PRT] group) or without radiotherapy to the primary tumor.Results
Patients in PRT group presented with a statistically significantly younger age (p = .02), whereas other characteristics showed no significant difference. Overall survival (OS) and biochemical failure-free survival (BCFFS) were improved in PRT patients (3-year OS: 69% vs. 43%, p = 0.004; 3-year BCFFS: 52% vs. 16%, p = 0.002). Multivariate analysis identified PRT as a significant predictor of both OS (hazard ratio [HR] = 0.43, p = 0.015). None of the 38 PRT patients experienced severe (grade ≥3) genitourinary or gastrointestinal toxicity.Conclusions
Our data suggest that radiotherapy to the primary tumor was associated with improved OS and BCFFS in metastatic prostate cancer. The results of this study warrant prospective controlled clinical trials of this approach in stage IV prostate cancer patients with limited extent of bone metastasis and good performance status. 相似文献46.
Kim JY Kim H Lee SG Choi BH Kim YH Huh PW Lee KH Han H Rha HK 《Biochemical and biophysical research communications》2003,310(3):904-909
The abnormal deposition of amyloid beta peptide (Abeta) is a hallmark of Alzheimer's disease (AD). Phospholipase C-delta1 (PLC-delta1) is also known to abnormally accumulate in the brains of AD patients, but no report has addressed the relationship between these two events. This study investigated the effect of Abeta42 on the PLC-delta1 expression in human neuroblastoma cell lines. The PLC-delta1 mRNA level was increased by treatment with Abeta42 in a RT-PCR analysis. In the reporter assay, Abeta42 was found to activate the PLC-delta1 promoter activity in a dose-dependent manner. A novel NF-kappaB binding site in the PLC-delta1 promoter appeared to be responsible for the Abeta42 activity. First, the dominant negative forms of the NF-kappaB activating molecules, dominant negative TGF-beta activated kinase 1 (dnTAK1) and dnNIK (dominant negative NF-kappaB-inducing kinase), abolished the Abeta42 activity in the reporter assay. Second, the Abeta42 augmented a factor binding on the NF-kappaB site in the electrophoretic mobility shift assay (EMSA), which was abolished by a molar excess of the unlabeled consensus NF-kappaB oligonucleotide. These results suggest that the PLC-delta1 promoter is under the control of NF-kappaB, which mediates the expression of PLC-delta due to the Abeta42 treatment. 相似文献
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49.
Abstract Conformational changes in ovalbumin, a globular protein, induced by an anionic surfactant, sodium dodecyl sulfate (SDS), have been monitored by an FT-IR spectrometer using ZnSe cylindrical internal reflection optics which allows high quality IR spectra to be obtained in water solution. The most notable change, on addition of SDS, occurs in the composite band of the Amide I absorption band and the vibrational frequency of the composite C=O bond shifts from 1639 cm?1 to 1652 cm?1. On the other hand, the position of the Amide II band remains fairly unchanged. Comparison of the various peak positions in the deconvoluted spectra for the native protein and the perturbed protein clearly shows the effect of SDS on the secondary structures of the protein. SDS unfolds the protein. It increases the helix content slightly. More importantly, it alters the β sheet structure, destroying it almost completely in the Amide I region, while retaining it in its neighbourhood. In the deconvoluted spectra of the perturbed protein, a band at 1531 cm?1 indicates generation of some β turns. We used the second derivative of the deconvoluted spectra for fixing positions of minor peaks and shoulders. The results of this study indicate that the deconvolution of the normal IR spectra, consisting of composite bands, provides evidence for the specific secondary structures in a protein and for the way they are affected by changes in the environment, e.g., the addition of SDS. This makes it possible to relate conformational changes to specific secondary structures. 相似文献
50.
Dae Keun Kim Kyo Chul Koo Ali Abdel Raheem Ki Hong Kim Byung Ha Chung Young Deuk Choi Koon Ho Rha 《PloS one》2016,11(3)