• Journal of Environmental Science International
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• v.29 no.3
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• pp.249-255
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• 2020

Particulate matter with an aerodynamic diameter of less than 2.5 μM (PM_2.5) is one of the major environmental pollutants. Di(2-ethylhexyl) phthalate (DEHP), an endocrine disrupting chemical in PM_2.5, has been utilized for the manufacturing of polyvinyl chloride to increase the flexibility of final products. In the present study, we investigated the ecotoxicological effect of DEHP on the viability of skin keratinocytes (HaCaT). DEHP induced apoptotic cell death mediated by phosphorylation of extracellular signal-regulated kinase through the production of intracellular Reactive Oxygen Species (ROS). Interestingly, we found that DEHP induces the phosphorylation of the nuclear factor-kappa B responsible for the expression of cleaved caspase-3 as an executional cell death protease in HaCaT cells. On the basis of these results, we suggest that DEHP in PM_2.5 induces the apoptotic death of human keratinocytes via ROS-mediated signaling events.

• KSBB Journal
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• v.5 no.1
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• pp.49-58
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• 1990

We constructed hybrid plasmids to allow controlled and extracellular production of human alpha-interferon in Escherichia coli. The hybrid plassmids were constructed by transferring alpha-lFN gene from plasmid Hif-2h which has the alpha-lFN gene at PstI restriction site of pBR322, to plasmids pIN -IIIB3 and pIN-IIIC3 at restriction sites between HindIII and BamHI. Plasmids pIN-IIIB3 and pIN-IIIC3 carry E. coli lipoprotein promoter, lac promoter and operator in tandem. The plasmids also have lacl genes which encode for lac repressors, which allows controlled expression of genes cloned to the plasmids by using of inducer IPTG. Lipoprotein signal sequence is located just ahead of cloning sites of the plasmids, which helps cells to excrete or secrete cloned gene products. Plasmid pUC9 was used as a intermediate vector for transferring of alpha-lFN gene from Hif-2h to pIN vectors in order to solve the problem of different restriction sites between Hif-2h and pIN vectors.

• Korean Journal of Microbiology
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• v.22 no.4
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• pp.257-263
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• 1984

A strain producing an extracellular cytosine deaminase was isolated from soil samples. The enzyme obtained from the strain possessed the substrate specificity to both cytosine and 5-fluorocytosine. From the results of its morphological, cultural, physiological, and biochemical properties, the strain was thought to be the genus Arthrobacter. Therefore, it was named as Arthrobacter sp. JH-13. The composition of optimum medium for the enzyme formation was 0.5% of peptone, 0.5% of meat extract, 0.5% of soluble starch, and 0.1% of KCl. The optimum pH for the enzyme formation was 8.0. When the microoganism was cultured aerobically in the above medium, enzyme production reached at maximum in 54 hours at $30^{\circ}C$.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.45-50
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• 2000

A submerged cultivation of Ganoderma lucidum was carried out in an air-lift fermenter system, and the effects of different pH processes on extracellular branched ${\beta}$-1,3-glucan(EPS) production and mycelial growth(MDW) were investigated. The controlled pH process improved the production of branched ${\beta}$-1,3-glucan and biomass in comparison to the uncontrolled pH process. However, the maximum production of branched ${\beta}$-1,3-glucan were obtained by the bi-staged pH process. From these results, we confirmed that the bi-staged pH process was the most effective for improving the production of branched ${\beta}$-1,3-glucan from submerged culture of G. lucidum.

• KSBB Journal
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• v.7 no.2
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• pp.102-106
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• 1992

Effects of nitrogen souses and C/N ratio were investigated on the production of extracellular microbial surfaclant, sophorolipid, from C. bombiocola. Organic nitrogen sources, such as urea, peptone and yeast extract was found to be more effective for sophorolipid production, than inorganic nitrogen sources. Depending on the nitrogen sources, sophorolipid production pattern varied by increasing C/N ratio. Increased production of sophrolipid could be obtained up to 90g/L by feeding carbon source again 2 days after cultivation.

• Molecules and Cells
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• v.23 no.1
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• pp.1-10
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• 2007

Invading pathogens are recognized by diverse germline-encoded pattern-recognition receptors (PRRs) which are distributed in three different cellular compartments: extracellular, membrane, and cytoplasmic. In mammals, the major extracellular PRRs such as complements may first encounter the invading pathogens and opsonize them for clearance by phagocytosis which is mediated by membrane-associated phagocytic receptors including complement receptors. The major membrane-associated PRRs, Toll-like receptors, recognize diverse pathogens and generate inflammatory signals to coordinate innate immune responses and shape adaptive immune responses. Furthemore, certain membrane-associated PRRs such as Dectin-1 can mediate phagocytosis and also induce inflammatory response. When these more forefront detection systems are avoided by the pathogens, cytoplasmic PRRs may play major roles. Cytoplasmic caspase-recruiting domain (CARD) helicases such as retinoic acid-inducible protein I (RIG-I)/melanoma differentiation-associated gene 5 (MDA5), mediate antiviral immunity by inducing the production of type I interferons. Certain members of nucleotide-binding oligomerization domain (NOD)-like receptors such as NALP3 present in the cytosol form inflammasomes to induce inflammatory responses upon ligand recognition. Thus, diverse families of PRRs coordinately mediate immune responses against diverse types of pathogens.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.546-554
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• 2019

This study, for the first time, reports the functional expression of lipase B derived from the yeast Candida antarctica (CALB) in Corynebacterium strain using the Escherichia coli plasmid PK18. The CALB gene fragment encoding a 317-amino-acid protein was successfully obtained from the total RNA of C. antarctica. CALB was readily produced in the Corynebacterium strain without the use of induction methods described in previous studies. This demonstrated the extracellular production of CALB in the Corynebacterium strain. CALB produced in the Corynebacterium MB001 strain transformed with pEC-CALB recombinant plasmid exhibited maximum extracellular enzymatic activity and high substrate affinity. The optimal pH and temperature for the hydrolysis of 4-nitrophenyl laurate by CALB were 9.0 and 40℃, respectively. The enzyme was stable at pH 10.7 in the glycine-KOH buffer and functioned as an alkaline lipase. The CALB activity was inhibited in the presence of high concentration of Mg²⁺, which indicated that CALB is not a metalloenzyme. These properties are key for the industrial application of the enzyme.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.1
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• pp.9-17
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• 2018

The aim of this study is to elucidate the biochemical properties of manno-oligosaccharides (MOS) hydrolyzed by extracellular enzyme of Bacillus N3. We strived to characterize the biochemical properties of MOS since N3 can effectively hydrolyzed natural polymannans such as galactomannan (GM) and konjac (glucomannan, KM), respectively. The hydrolysis of GM and KM was applied by the strain N3 in terms of reducing sugars and the highest production of reducing sugars was estimated to be about 750 mg/L and 370 mg/L respectively, which were quantified after 7 days of cultivation in the presence of both substrates. Hydrolysates derived from the hydrolysis of KM showed the significant antioxidant activity based on DPPH and ABTS radical scavenging activity with increasing of tyrosinase inhibitory activity. On the other hand, hydrolysates derived from the hydrolysis of GM showed only ABTS radical scavenging activity without showing significant changes on tyrosinase inhibitory activity. Our data suggest that those biological characteristics may be depend on the primary structure and the size of MOS, which may be useful as potent additives for diet foods.

• BMB Reports
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• v.55 no.1
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• pp.20-29
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• 2022

Stem cell-based therapy is a promising approach for treating a variety of disorders, including acute brain insults and neurodegenerative diseases. Stem cells such as mesenchymal stem cells (MSCs) secrete extracellular vesicles (EVs), circular membrane fragments (30 nm-1 ㎛) that are shed from the cell surface, carrying several therapeutic molecules such as proteins and microRNAs. Because EV-based therapy is superior to cell therapy in terms of scalable production, biodistribution, and safety profiles, it can be used to treat brain diseases as an alternative to stem cell therapy. This review presents evidences evaluating the role of stem cell-derived EVs in stroke, traumatic brain injury, and degenerative brain diseases, such as Alzheimer's disease and Parkinson' disease. In addition, stem cell-derived EVs have better profiles in biocompatibility, immunogenicity, and safety than those of small chemical and macromolecules. The advantages and disadvantages of EVs compared with other strategies are discussed. Even though EVs obtained from native stem cells have potential in the treatment of brain diseases, the successful clinical application is limited by the short half-life, limited targeting, rapid clearance after application, and insufficient payload. We discuss the strategies to enhance the efficacy of EV therapeutics. Finally, EV therapies have yet to be approved by the regulatory authorities. Major issues are discussed together with relevant advances in the clinical application of EV therapeutics.

• Journal of Life Science
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• v.19 no.4
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• pp.457-461
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• 2009

We optimized dextranase culture conditions by batch fermentation using Lipomyces starkeyi KCTC 17343. Furthermore, dextranase was purified by an ultra-membrane, and then dextran hydrolyzates were characterized. Cell growth and dextranase production varied depending on the initial culture pH and temperature. The conditions of optimal dextranase production were met in a pH range of 4-5 and temperature between $25-30^{\circ}C$. At optimal fermentation conditions, total enzyme activity and specific enzyme activity were about 4.85 IU/ml and 0.79 IU/g cells, respectively. The specific growth rate was examined to be $0.076\;hr^{-1}$. The production of dextranase in culture broth was very stably maintained after mid-log phase of growth. The enzyme hydrolyzed dextran into DP (degree of polymerization) 2 to 8 oligodextran series. Analysis of the composition of hydrolysates suggested that the enzyme produced is an endo-dextranase.