• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1249-1256
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• 2017

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Leu-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Phe-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Phe)$, and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line.

• 한국조리학회지
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• 제22권6호
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• pp.71-77
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• 2016

To determine the nutritional value of domestic tomatoes, the levels of amino acids, amino acid metabolites, and the bioactive compound ${\gamma}-aminobutyric-acid$ (GABA) were analyzed in three domestic tomato varieties (Rafito, Momotaro, and Medison). Eighteen free amino acids were found, and total free amino acid content was 3,810.21~4,594.56 mg/100 g (dry weight). L-glutamic acid (L-Glu) was the most abundant amino acid, ranging from 1,866.60 mg/100 g for Momotaro to 2,417.45 mg/100 g for Medison. The next most abundant amino acids were L-glutamine (L-Gln) and L-aspartic acid (L-Asp). The three tomato varieties had a good balance of all the essential amino acids except tryptophan. Total essential amino acid content was 274.26~472.71 mg/100 g (dry weight). The following amino acid metabolites were found: L-carnitine (L-Car), hydroxylysine (Hyl), o-phosphoethanolamine (o-Pea), phosphoserine (p-Ser), ${\beta}-alanine$ (${\beta}-Ala$), N-methyl-histidine (Me-His), ethanolamine (EtNH2),and L-citrulline(L-Cit). Large quantities of GABA were found in all three varieties: 666.95-868.48 mg/100g (dry weight). These results support the use of these tomato varieties as nutritious food materials.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1142-1149
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• 2009

Several bioactive metabolites, including pyrrolnitrin, N-acylhomoserine lactones, and polyhydroxyalkanoates were isolated from Burkholderia sp. O33. Effects of various nutrients, including sugars, gluconolactone, glycerol, tryptophan, chloride, and zinc were investigated in relation to the production of these metabolites. Logarithmic increase of pyrrolnitrin was observed between 2-5 days and reached a maximum at 7-10 days. Tryptophan concentration reached the maximum at 3 days, whereas 7-chlorotryptophan was gradually increased throughout the studies. Among various carbon sources, gluconolactone, trehalose, and glycerol enhanced pyrrolnitrin production, whereas strong inhibitory effects were found with glucose. Relative concentrations of pyrrolnitrin and its precursors were in the order of pyrrolnitrin$\gg$dechloroaminopyrrolnitrin or aminopyrrolnitrin throughout the experiments. Among three N-acylhomoserine lactones, the N-octanoyl analog was the most abundant quorum sensing signal, of which the concentrations reached the maximum in 2-3 days, followed by a rapid dissipation to trace level. No significant changes in pyrrolnitrin biosynthesis were observed by external addition of N-acylhomoserine lactones. Polyhydroxyalkanoates accumulated up to 3-4 days and decreased slowly thereafter. According to the kinetic analyses, no strong correlations were found between the levels of pyrrolnitrin, N-acylhomoserine lactones, and polyhydroxyalkanoates.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1787-1795
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• 2015

The transition from primary to secondary metabolism in antibiotic-producing Streptomyces correlates with expression of genes involved in stress responses. Consequently, regulatory pathways that regulate specific stress responses are potential targets to manipulate to increase antibiotic titers. In this study, genes encoding key proteins involved in regulation of the osmotic stress response in Streptomyces avermitilis, the industrial producer of avermectins, are investigated as targets. Disruption of either osaB_Sa, encoding a response regulator protein, or osaC_Sa, encoding a multidomain regulator of the alternative sigma factor SigB, led to increased production of both oligomycin, by up to 200%, and avermectin, by up to 37%. The mutations also conditionally affected morphological development; under osmotic stress, the mutants were unable to erect an aerial mycelium. In addition, we demonstrate the delivery of DNA into a streptomycete using biolistics. The data reveal that information on stress regulatory responses can be integrated in rational strain improvement to improve yields of bioactive secondary metabolites.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.2006-2011
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• 2016

The marine sponges Hyrtios and Haliclona species, both of which are known to produce secondary bioactive metabolites, were used to extract 1304KO-327 and 1304KO-328. Such secondary metabolites are potentially antibacterial, antiviral, anti-inflammatory, antitumoral, antifungal, and antiplasmodial. In the present study, the effects of 1304KO-327 and 1304KO-328 were studied for their clinical and pathological importance. The cytotoxicity of 1304KO-327 and 1304KO-328 was assessed via MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on HT-29, Caco-2, and Raw 264.7 cells. Rotavirus-infected Caco-2 cells were used to prove the antiviral effects of the marine sponge extracts. The test results cogently proved that the virus-inhibiting effects of the sponge extracts improved with extract concentration. Anti-inflammatory effects of the marine sponge extracts were tested on Lipopolysaccharide-treated Raw 264.7 cells. Nitric oxide and cytokine were produced by treatment of the cells with LPS and the inhibiting effects of the sponge extracts on $IL-1{\beta}$ formation were investigated. This study found that the NO production was decreased dose dependently, and $IL-1{\beta}$ formation was significantly reduced by the marine sponge extracts.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1314-1321
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• 2024

Branched-chain hydroxy acids (BCHAs), produced by lactic acid bacteria, have recently been suggested as bioactive compounds contributing to the systemic metabolism and modulation of the gut microbiome. However, the relationship between BCHAs and gut microbiome remains unclear. In this study, we investigated the effects of BCHAs on the growth of seven different families in the gut microbiota. Based on in vitro screening, both 2-hydroxyisovaleric acid (HIVA) and 2-hydroxyisocaproic acid (HICA) stimulated the growth of Lactobacillaceae and Bifidobacteriaceae, with HIVA showing a significant growth promotion. Additionally, we observed not only the growth promotion of probiotic Lactobacillaceae strains but also growth inhibition of pathogenic B. fragilis in a dose-dependent manner. The production of HIVA and HICA varied depending on the family of the gut microbiota and was relatively high in case of Lactobacillaceae and Lachnosporaceae. Furthermore, HIVA and HICA production by each strain positively correlated with their growth variation. These results demonstrated gut microbiota-derived BCHAs as active metabolites that have bacterial growth modulatory effects. We suggest that BCHAs can be utilized as active metabolites, potentially contributing to the treatment of diseases associated with gut dysbiosis.

• 생명과학회지
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• 제31권9호
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• pp.862-872
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• 2021

최근 생물의학 분야에서의 광범위한 응용 가능성에 의하여 식물이나 미생물을 이용한 은(Ag), 금(Au), 백금(Pt), 세륨(Ce), 아연(Zn), 구리(Cu) 등의 금속 나노물질 합성에 관한 연구가 주목받고 있다. 식물은 플라보노이드, 알칼로이드, 사포닌, 스테로이드 탄닌과 각종 영양 성분과 같은 생리 활성 물질을 풍부하게 가지고 있으며, 유사하게 미생물들도 단백질과 같은 생리활성 대사산물이나 색소, 항생제 및 산과 같은 가치가 있는 화학물질을 분비한다. 최근 보고된 바에 의하면, 나노입자의 생체 합성은 무해한 방법일 뿐만 아니라 항균, 항진균, 세포 증식 억제 및 항플라스모디아 활성과 같은 생물의학 분야로서의 적용에 주요한 후보로 여겨진다. 나노입자의 이러한 생리 활성은 농도에 의존적이며, 나노입자의 모양과 크기에도 따라 달라질 수 있다. 미생물과 식물은 나노입자의 친환경적합성에 사용되는 대사산물이나 화학물질 등의 훌륭한 공급원으로서 생물 의학 분야에서 유용하게 사용된다. 미생물 또는 식물 원료를 사용하여 합성된 나노입자는 화학적인 방법으로 합성된 나노입자보다 더 낮은 독성을 나타낸다. 본 리뷰논문에서는 미생물이나 식물과 같은 생물학적 재료를 이용한 나노입자의 합성과, 합성에 사용되는 다양한 기술의 특성 및 나노입자의 항균 분야에서의 적용에 대하여 중점적으로 서술하였다.

• Journal of Plant Biotechnology
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• 제4권3호
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• pp.109-115
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• 2002

Submerged cultures of Ganoderma lucidum, a valuable mushroom in traditional Chinese medicine, were used for production of bioactive Banoderic acids and Ganoderma polysaccharides. The significant effects of oxygen supply were demonstrated in both shake flasks and bioreactors. By changing the medium loading volume in a shake flask, a different value of initial volumetric oxygen transfer coefficient ($K_L$a) was obtained, and a higher $K_L$a value led to a higher biomass density and a higher productivity of both intracellular polysaccharide and ganoderic acid. In a stirred bioreactor, at an initial $K_L$a of 78.2 $h^{-1}$, a maximal cell concentration of 15.6 g/L by dry weight was obtained, as well as a maximal intracellular polysarcharide (IPS) production of 2.2 g/L and its maximal productivity of 220 mg/(L.d). An increase of initial $K_L$a led to a higher production and productivity of GA, and the GA production and productivity at an initial $K_L$a of 96.0 $h^{-1}$ was 1.8-fold those at an initial $K_L$a of 16.4 $h^{-1}$. The fundamental information obtained in this study may be useful for efficient large-scale production of these valuable bioactive products by the submerged cultures.

• ALGAE
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• 제27권4호
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• pp.303-313
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• 2012

Cyanobacteria are well known for their production of a multitude of highly toxic and / or allelopathic compounds. Among the photosynthetic microorganisms, cyanobacteria, belonging to the genus Nostoc are regarded as good candidate for producing biologically active secondary metabolites which are highly toxic to humans and other animals. Since so many reports have been published on the poisoning of different animals from drinking water contaminated with cyanobacteria toxins, it might be assumed that bioactive compounds are found only in aquatic species causes toxicity. However, the discovery of several dead dogs, mice, ducks, and fish around paddy fields, prompted us to study the toxic compounds in a strain of Nostoc which is most abundant in the paddy fields of Iran, using polymerase chain reaction and liquid chromatography coupled with a diode array detector and mass spectrophotometer. Results of molecular analysis demonstrated that the ASN_M strain contains the nosF gene. Also, the result of ion chromatograms and $MS^2$ fragmentation patterns showed that while there were three different peptidic compound classes (anabaenopeptin, cryptophycin, and nostocyclopeptides), there were no signs of the presence of anatoxin-a, homoanatoxin-a, hassallidin or microcystins. Moreover, a remarkable antifungal activity was identified in the methanolic extracts. Based on the results, this study suggests that three diverse groups of potentially bioactive compounds might account for the death of these animals. This case is the first documented incident of toxicity from aquatic cyanobacteria related intoxication in dogs, mice, and aquatic organisms in Iran.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1109-1114
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• 2008

To understand the role of intestinal microflora in the biological effect of functional herbs, which have been used in Korea, Japan, and China as traditional medicines, and suggest new bioactive compounds transformed from herbal constituents, the metabolic activities of the functional herb components (ginsenoside Rb1, crocin, amygdalin, geniposide, puerarin, ginsenoside Re, poncirin, hesperidin, glycyrrhizin, and baicalin) toward their bioactive compounds (compound K, crocetin, benzaldehyde, genipin, daidzein, ginsenoside Rh1, ponciretin, hesperetin, 18b-glycyrrhetic acid, and baicalein) were measured in fecal specimens. The metabolic activities of these components were $882.7{\pm}814.5$, $3,938.1{\pm}2,700.8$, $2,375.5{\pm}913.7$, $1,179.4{\pm}795.7$, $24.6{\pm}10.5$, $11.4{\pm}10.8$, $578.8{\pm}206.1$, $1,150.0{\pm}266.1$, $47.3{\pm}58.6$, and $12,253.0{\pm}6,527.6\;{\mu}mol/h/g$, respectively. No differences were found in the metabolic activities of the tested components between males and females, although these metabolic activities between individuals are extensively different. The metabolites of functional herb components showed more potent cytotoxicity against tumor cells than nonmetabolites. These findings suggest that intestinal microflora may activate the pharmacological effect of herbal food and medicines and must be the biocatalytic converter for the transformation of herbal components to bioactive compounds.