• Journal of Microbiology
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• 제42권2호
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• pp.152-155
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• 2004

Pseudomonas sp. K82 has been reported to be an aniline-assimilating soil bacterium. However, this strain can use not only aniline as a sole carbon and energy source, but can also utilize benzoate, p-hydroxybenzoate, and aniline analogues. The strain accomplishes this metabolic diversity by using dif-ferent aerobic pathways. Pseudomonas sp. K82, when cultured in p-hydroxybenzoate, showed extradiol cleavage activity of protocatechuate. In accordance with those findings, our study attempted the puri-fication of protocatechuate 4,5-dioxygenase (PCD 4,5). However the purified PCD 4,5 was found to be very unstable during purification. After Q-sepharose chromatography was performed, the crude enzyme activity was augmented by a factor of approximately 4.7. From the Q-sepharose fraction which exhibited PCD 4,5 activity, two subunits of PCD4,5 (${\alpha}$ subunit and ${\beta}$ subunit) were identified using the N-terminal amino acid sequences of 15 amino acid residues. These subunits were found to have more than 90％ sequence homology with PmdA and PmdB of Comamonas testosteroni. The molecular weight of the native enzyme was estimated to be approximately 54 kDa, suggesting that PCD4,5 exists as a het-erodimer (${\alpha}$$_1$${\beta}$$_1$). PCD 4,5 exhibits stringent substrate specificity for protocatechuate and its optimal activity occurs at pH 9 and 15 $^{\circ}C$. PCR amplification of these two subunits of PCD4,5 revealed that the ${\alpha}$ subunit and ${\beta}$ subunit occurred in tandem. Our results suggest that Pseudomonas sp. K82 induced PCD 4,5 for the purpose of p-hydroxybenzoate degradation.

• Journal of Plant Biotechnology
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• 제41권4호
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• pp.169-179
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• 2014

세포내에는 비효소적 반응으로 활성산소류를 제거하는 소분자의 항산화 물질과 과산소와 하이드로페록사이드를 분해하는 효소들이 존재한다. 항산화 시스템은 자유라디칼과 활성산소류를 제거함으로써 산화스트레스로부터 세포 구성요소들을 보호하는 역할을 한다. 비효소적 항산화 물질은 지용성과 친수성이 있는데, 지용성 물질들은 세포막에 위치하며 과산화지질이 형성되는 반응을 억제한다. 카로테노이드와 비타민E, $CoQ_{10}$은 세포 내에서 주요 지용성 항산화 물질로써, 이들이 대량으로 축적된 주요 작물의 개발은 영양학적 가치가 높은 식품을 생산할 수 있다. 본 총설에서는 식물에서 카로테노이드와 비타민E, $CoQ_{10}$의 생합성 경로와 대사공학을 이용한 영양강화 연구 현황을 기술하였다.

• 한국해양바이오학회지
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• 제8권2호
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• pp.45-53
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• 2016

Most of microalgae shift their metabolic pathways toward the fatty acid biosynthesis following nitrogen deprivation. Recent studies on Nannochloropsis species, oleaginous microalgae, have been performed to investigate the regulation of contents and compositions of fatty acids under stressful condition. The objective of this experiment is to identify the effect of nitrogen on cell growth and fatty acids production in Nannochloropsis oculata K-1281 and compare fatty acid composition response to nitrogen deficiency between N. oculata LB2164 and K-1281. The fatty acids content in N. oculata K-1281 was increased up to 210%, while the growth rate was decreased under nitrogen deficient condition. The contents of C16:0 and C16:1 increased dramatically in both N. oculata K-1281 and LB2164, while the contents of C20:4 and C20:5 increased in N. oculata LB2164. The fatty acids content and composition in N. oculata K-1281 returned following addition of nitrogen after nitrogen starvation. These results demonstrated that fatty acid contents and compositions under nitrogen deficiency will provide the understanding of fatty acid synthesis in microalgae.

• Genes and Genomics
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• 제40권11호
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• pp.1157-1167
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• 2018

Sulfolobus species can grow on a variety of organic compounds as carbon and energy sources. These species degrade glucose to pyruvate by the modified branched Entner-Doudoroff pathway. We attempted to determine the differentially expressed genes (DEGs) under sugar-limited and sugar-rich conditions. RNA sequencing (RNA-seq) was used to quantify the expression of the genes and identify those DEGs between the S. acidocaldarius cells grown under sugar-rich (YT with glucose) and sugar-limited (YT only) conditions. The functions and pathways of the DEGs were examined using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Quantitative real-time PCR (qRT-PCR) was performed to validate the DEGs. Transcriptome analysis of the DSM 639 strain grown on sugar-limited and sugar-rich media revealed that 853 genes were differentially expressed, among which 481 were upregulated and 372 were downregulated under the glucose-supplemented condition. In particular, 70 genes showed significant changes in expression levels of ${\geq}$ twofold. GO and KEGG enrichment analyses revealed that the genes encoding components of central carbon metabolism, the respiratory chain, and protein and amino acid biosynthetic machinery were upregulated under the glucose condition. RNA-seq and qRT-PCR analyses indicated that the sulfur assimilation genes (Saci_2197-2204) including phosphoadenosine phosphosulfate reductase and sulfite reductase were significantly upregulated in the presence of glucose. The present study revealed metabolic networks in S. acidocaldarius that are induced in a glucose-dependent manner, improving our understanding of biomass production under sugar-rich conditions.

• Genes and Genomics
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• 제40권12호
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• pp.1287-1300
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• 2018

Hydrogen sulfide ($H_2S$), a small bioactive gas, has been proved functioning in plant growth and development as well as alleviation of abiotic stresses, which including promoting seed germination, accelerating embryonic root growth, regulating flower senescence, inducing stomatal closure, and defending drought, heat, heavy metals and osmotic stresses etc. However, the molecular functioning mechanism of $H_2S$ was still unclear. The primary objective of this research was to analyze the transcriptional differences and functional genes involved in the $H_2S$ responses. In details, 4-week-old plantlets in tissue culture of grapevine (Vitis vinifera L.) cultivar 'Zuoyouhong' were sprayed with 0.1 mM NaHS for 12 h, and then transcriptome sequencing and qRT-PCR analysis were used to study the transcriptional differences and functional genes involved in the $H_2S$ responses. Our results indicated that 650 genes were differentially expressed after $H_2S$ treatment, in which 224 genes were up-regulated and 426 genes were down-regulated. The GO enrichment analysis and KEGG enrichment analysis results indicated that the up-regulated genes after $H_2S$ treatment focused on carbon metabolism, biosynthesis of amino acids, and glycolysis/gluconeogenesis, and the down-regulated genes were mainly in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Analyzing the transcription factor coding genes in details, it was indicated that 10 AP2/EREBPs, 5 NACs, 3 WRKYs, 3 MYBs, and 2 bHLHs etc. transcription factor coding genes were up-regulated, while 4 MYBs, 3 OFPs, 3 bHLHs, 2 AP2/EREBPs, 2 HBs etc. transcription factor coding genes were down-regulated. Taken together, $H_2S$ increased the productions in secondary metabolites and a variety of defensive compounds to improve plant development and abiotic resistance, and extend fruits postharvest shelf life by regulating the expression of AP2/EREBPs, WRKYs, MYBs, CABs, GRIP22, FERRITINs, TPSs, UGTs, and GHs etc.

• The Plant Pathology Journal
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• 제35권4호
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• pp.330-340
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• 2019

The present study was undertaken to evaluate the integrated effect of zinc (Zn) with other nutrients in managing early blight (EB) disease in tomato. A pot experiment was carried out with basal application of the recommended level of macronutrients [nitrogen, phosphorus and potassium (NPK)] and micronutrients [magnesium (Mg) and boron (B)] in bilateral combination with Zn (2.5 and 5.0 mg/kg) in a completely randomized deigned in replicates. Results revealed that interactive effect of Zn with Mg or B was often futile and in some cases synergistic. Zn with NPK yield synergistic outcome, therefore EB disease was managed significantly (disease incidence: 25% and percent severity index: 13%), which resulted in an efficient signaling network that reciprocally controls nutrient acquisition and uses with improved growth and development in a tomato plant. Thus, crosstalk and convergence of mechanisms in metabolic pathways resulted in induction of resistance in tomato plant against a pathogen which significantly improved photosynthetic pigment, total phenolics, total protein content and defense-related enzymes [superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL)]. The tremendous increase in total phenolics and PAL activity suggesting their additive effect on salicylic acid which may help the plant to systemically induce resistance against pathogen attack. It was concluded that interactive effect of Zn (5.0 mg/kg) with NPK significantly managed EB disease and showed positive effect on growth, physiological and biochemical attributes therefor use of Zn + NPK is simple and credible efforts to combat Alternaria stress in tomato plants.

• Korean Journal of Acupuncture
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• 제35권4호
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• pp.187-202
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• 2018

Objectives : Non-invasive transcranial electrical stimulation is one of therapeutic interventions to change in neural excitability of the cortex. Transcranial electro-acupuncture (TEA) can modulate brain functions through changes in cortical excitability as a model of non-invasive transcranial electrical stimulation. Some composites of fermented Scutellaria baicalenis (FSB) can activate intercellular signaling pathways for activation of brain-derived neurotrophic factor that is critical for formation of neural plasticity in stroke patients. This study was aimed at evaluation of combinatory treatment of TEA and FSB on behavior recovery and cortical neural excitability in rodent focal stroke model. Methods : Focal ischemic stroke was induced by photothrombotic injury to the motor cortex of adult rats. Application of TEA with 20 Hz and $200{\mu}A$ in combination with daily oral treatment of FBS was given to stroke animals for 3 weeks. Motor recovery was evaluated by rotating bean test and ladder working test. Electrical activity of cortical pyramidal neurons of stroke model was evaluated by using multi-channel extracellular recording technique and thallium autometallography. Results : Compared with control stroke group who did not receive any treatment, Combination of TEA and FSB treatment resulted in more rapid recovery of forelimb movement following focal stroke. This combination treatment also elicited increase in spontaneous firing rate of putative pyramidal neurons. Furthermore expression of metabolic marker for neural excitability was upregulated in peri-infract area under thallium autometallography. Conclusions : These results suggest that combination treatment of TEA and FSB can be a possible remedy for motor recovery in focal stroke.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.429-440
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• 2019

Several studies have attempted to identify factors associated with longevity and maintenance of health in centenarians. In this study, we analyzed and compared the gut microbiota of centenarians in longevity villages with the elderly and adults in the same region and urbanized towns. Fecal samples were collected from centenarians, elderly, and young adults in longevity villages, and the gut microbiota sequences of elderly and young adults in urbanized towns of Korea were obtained from public databases. The relative abundance of Firmicutes was found to be considerably higher in subjects from longevity villages than those from urbanized towns, whereas Bacteroidetes was lower. Age-related rearrangement of gut microbiota was observed in centenarians, such as reduced proportions of Faecalibacterium and Prevotella, and increased proportion of Escherichia, along with higher abundances of Akkermansia, Clostridium, Collinsella, and uncultured Christensenellaceae. Gut microbiota of centenarians in rehabilitation hospitals were also different to those residing at home. These differences could be due to differences in diet patterns and living environments. In addition, phosphatidylinositol signaling system, glycosphingolipid biosynthesis, and various types of N-glycan biosynthesis were predicted to be higher in the gut microbiota of centenarians (corrected p < 0.05). These three metabolic pathways of gut microbiota can be associated with the immune status and healthy gut environment of centenarians. Although further studies are necessary to validate the function of microbiota between groups, this study provides valuable information on centenarians' gut microbiota.

• Journal of Ginseng Research
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• 제43권4호
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• pp.539-549
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• 2019

Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

• The Plant Pathology Journal
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• 제37권1호
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• pp.36-46
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• 2021

Acidovorax citrulli (Ac) is the causal agent of bacterial fruit blotch (BFB) in watermelon, a disease that poses a serious threat to watermelon production. Because of the lack of resistant cultivars against BFB, virulence factors or mechanisms need to be elucidated to control the disease. Glycerol-3-phosphate dehydrogenase is the enzyme involved in glycerol production from glucose during glycolysis. In this study, we report the functions of a putative glycerol-3-phosphate dehydrogenase in Ac (GlpdAc) using comparative proteomic analysis and phenotypic observation. A glpdAc knockout mutant, AcΔglpdAc(EV), lost virulence against watermelon in two pathogenicity tests. The putative 3D structure and amino acid sequence of GlpdAc showed high similarity with glycerol-3-phosphate dehydrogenases from other bacteria. Comparative proteomic analysis revealed that many proteins related to various metabolic pathways, including carbohydrate metabolism, were affected by GlpdAc. Although AcΔglpdAc(EV) could not use glucose as a sole carbon source, it showed growth in the presence of glycerol, indicating that GlpdAc is involved in glycolysis. AcΔglpdAc(EV) also displayed higher cell-to-cell aggregation than the wild-type bacteria, and tolerance to osmotic stress and ciprofloxacin was reduced and enhanced in the mutant, respectively. These results indicate that GlpdAc is involved in glycerol metabolism and other mechanisms, including virulence, demonstrating that the protein has pleiotropic effects. Our study expands the understanding of the functions of proteins associated with virulence in Ac.