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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Microbiology and Biotechnology
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 23, Issue 12 - Dec 2013
Volume 23, Issue 11 - Nov 2013
Volume 23, Issue 10 - Oct 2013
Volume 23, Issue 9 - Sep 2013
Volume 23, Issue 8 - Aug 2013
Volume 23, Issue 7 - Jul 2013
Volume 23, Issue 6 - Jun 2013
Volume 23, Issue 5 - May 2013
Volume 23, Issue 4 - Apr 2013
Volume 23, Issue 3 - Mar 2013
Volume 23, Issue 2 - Feb 2013
Volume 23, Issue 1 - Jan 2013
Selecting the target year
Short-Term Effect of Elevated Temperature on the Abundance and Diversity of Bacterial and Archaeal amoA Genes in Antarctic Soils
Han, Jiwon ; Jung, Jaejoon ; Park, Minsuk ; Hyun, Seunghun ; Park, Woojun ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1187~1196
DOI : 10.4014/jmb.1305.05017
Global warming will have far-reaching effects on our ecosystem. However, its effects on Antarctic soils have been poorly explored. To assess the effects of warming on microbial abundance and community composition, we sampled Antarctic soils from the King George Island in the Antarctic Peninsula and incubated these soils at elevated temperatures of
for 14 days. The reduction in total organic carbon and increase in soil respiration were attributed to the increased proliferation of Bacteria, Fungi, and Archaea. Interestingly, bacterial ammonia monooxygenase (amoA) genes were predominant over archaeal amoA, unlike in many other environments reported previously. Phylogenetic analyses of bacterial and archaeal amoA communities via clone libraries revealed that the diversity of amoA genes in Antarctic ammonia-oxidizing prokaryotic communities were temperature-insensitive. Interestingly, our data also showed that the amoA of Antarctic ammonia-oxidizing bacteria (AOB) communities differed from previously described amoA sequences of cultured isolates and clone library sequences, suggesting the presence of novel Antarctic-specific AOB communities. Denitrification-related genes were significantly reduced under warming conditions, whereas the abundance of amoA and nifH increased. Barcoded pyrosequencing of the bacterial 16S rRNA gene revealed that Proteobacteria, Acidobacteria, and Actinobacteria were the major phyla in Antarctic soils and the effect of short-term warming on the bacterial community was not apparent.
Expression, Purification, and Biological Characterization of The Amino-Terminal Fragment of Urokinase in Pichia pastoris
Li, Jianping ; Lin, Yuli ; Zhuang, Hongqin ; Hua, Zi-Chun ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1197~1205
DOI : 10.4014/jmb.1305.05004
Urokinase (uPA) and its receptor (uPAR) play an important role in tumor growth and metastasis. Targeting the excessive activation of this system as well as the proliferation of the tumor vascular endothelial cell would be expected to prevent tumor neovasculature and halt the tumor development. In this regard, the amino-terminal fragment (ATF) of urokinase has been confirmed as effective to inhibit the proliferation, migration, and invasiveness of cancer cells via interrupting the interaction of uPA and uPAR. Previous studies indicated that ATF expressed in Escherichia coli was mainly contained in inclusion bodies and also lacked posttranslational modifications. In this study, the biologically active and soluble ATF was cloned and expressed in Pichia pastoris. The recombinant protein was purified to be homogenous and confirmed to be biologically active. The yield of the active ATF was about 30 mg/l of the P. pastoris culture medium. The recombinant ATF (rATF) could efficiently inhibit angiogenesis, endothelial cell migration, and tumor cell invasion in vitro. Furthermore, it could inhibit in vivo xenograft tumor growth and prolong the survival of tumor-bearing mice significantly by competing with uPA for binding to cell surfaces. Therefore, P. pastoris is a highly efficient and cost-effective expression system for large-scale production of biologically active rATFs for potential therapeutic application.
PTP1B Inhibitory Secondary Metabolites from Marine-Derived Fungal Strains Penicillium spp. and Eurotium sp.
Sohn, Jae Hak ; Lee, Yu-Ri ; Lee, Dong-Sung ; Kim, Youn-Chul ; Oh, Hyuncheol ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1206~1211
DOI : 10.4014/jmb.1303.03078
The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory fungal metabolites, the organic extracts of several fungal species isolated from marine environments were found to exhibit significant inhibitory effects, and the bioassay-guided investigation of these extracts resulted in the isolation of fructigenine A (1), cyclopenol (2), echinulin (3), flavoglaucin (4), and viridicatol (5). The structures of these compounds were determined mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 10.7, 30.0, 29.4, 13.4, and 64.0
, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compounds 1 and 5 suggested that compound 1 inhibited PTP1B activity in a noncompetitive manner, whereas compound 5 inhibited PTP1B activity in a competitive manner.
Chemically Modified Sepharose as Support for the Immobilization of Cholesterol Oxidase
Yang, Hailin ; Chen, Yi ; Xin, Yu ; Zhang, Ling ; Zhang, Yuran ; Wang, Wu ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1212~1220
DOI : 10.4014/jmb.1304.03103
Because the cholesterol oxidase from Brevibacterium sp. M201008 was not as stable as the free enzyme form, it had been covalently immobilized onto chemically modified Sepharose particles via N-ethyl-N'-3-dimethylaminopropyl carbodiimide. The optimum immobilization conditions were determined, and the immobilized enzyme activity obtained was 12.01 U/g Sepharose-ethylenediamine. The immobilization of the enzyme was characterized by Fourier transform infrared spectroscopy. The immobilized enzyme exhibited the maximal activity at
and pH 7.5, which was unchanged compared with the free form. After being repeatedly used 20 times, the immobilized enzyme retained more than 40.43% of its original activity. The immobilized enzyme showed better operational stability, including wider thermal and pH ranges, and retained 62.87% activity after 20 days of storage at
, which was longer than the free enzyme.
Expression and Biochemical Characterization of Cold-Adapted Lipases from Antarctic Bacillus pumilus Strains
Litantra, Ribka ; Lobionda, Stefani ; Yim, Joung Han ; Kim, Hyung Kwoun ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1221~1228
DOI : 10.4014/jmb.1305.05006
Two lipase genes (bpl1 and bpl3) from Antarctic Bacillus pumilus strains were expressed in Bacillus subtilis. Both recombinant lipases BPL1 and BPL2 were secreted to the culture medium and their activities reached 3.5 U/ml and 5.0 U/ml, respectively. Their molecular masses apparent using SDS-PAGE were 23 kDa for BPL1 and 19 kDa for BPL3. Both lipases were purified to homogeneity using ammonium sulfate precipitation and HiTrap SP FF column and Superose 12 column chromatographies. The final specific activities were estimated to be 328 U/mg for BPL1 and 310 U/mg for BPL3. Both lipases displayed an optimum temperature of
, similar to other mesophilic enzymes. However, they maintained as much as 70% and 80% of the maximum activities at
. Accordingly, their calculated activation energy at a temperature range of
was 5.32 kcal/mol for BPL1 and 4.26 kcal/mol for BPL3, typical of cold-adapted enzymes. The optimum pH of BPL1 and BPL3 was 8.5 and 8.0, respectively, and they were quite stable at pH 7.0-11.0, showing their strong alkaline tolerance. Both lipases had a preference toward medium chain length (
) fatty acid substrates. These results indicate the potential for the two Antarctic B. pumilus lipases as catalysts in bioorganic synthesis, food, and detergent industries.
Biosurfactant Production from Novel Air Isolate NITT6L: Screening, Characterization and Optimization of Media
Vanavil, B. ; Perumalsamy, M. ; Rao, A. Seshagiri ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1229~1243
DOI : 10.4014/jmb.1212.12031
In this paper, an air isolate (NITT6L) has been screened based on hemolytic activity, emulsification activity, drop collapsing test, and oil displacement test, as well as lipase activity. It was found that strain NITT6L was able to reduce the surface tension of the medium from 61.5 to 39.83 mN/m and could form stable emulsions with tested vegetable oils. Morphological, biochemical, 16S rRNA sequencing analyses, and fatty acid methyl ester analysis using gas chromatography confirmed that the air isolate under study was Pseudomonas aeruginosa. Characterization of the biosurfactant using agar double diffusion assay revealed that the biosurfactant was anionic in nature, and CTAB-methylene blue assay and Molisch test revealed its glycolipid nature. The FT-IR spectrum confirmed that the crude biosurfactant was a rhamnolipid. Using unoptimized medium containing sucrose as the carbon source, the isolate was found to produce 0.3 mg/ml of rhamnolipid in batch cultivation (shake flask) at
and pH 7. Optimization of the medium components was carried out using design of experiments and the yield of rhamnolipid has been enhanced to 4.6 mg/ml in 72 h of fermentation.
Integrated Hydrolyzation and Fermentation of Sugar Beet Pulp to Bioethanol
Rezic, Tonic ; Oros, Damir ; Markovic, Iva ; Kracher, Daniel ; Ludwig, Roland ; Santek, Bozidar ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1244~1252
DOI : 10.4014/jmb.1210.10013
Sugar beet pulp is an abundant industrial waste material that holds a great potential for bioethanol production owing to its high content of cellulose, hemicelluloses, and pectin. Its structural and chemical robustness limits the yield of fermentable sugars obtained by hydrolyzation and represents the main bottleneck for bioethanol production. Physical (ultrasound and thermal) pretreatment methods were tested and combined with enzymatic hydrolysis by cellulase and pectinase to evaluate the most efficient strategy. The optimized hydrolysis process was combined with a fermentation step using a Saccharomyces cerevisiae strain for ethanol production in a single-tank bioreactor. Optimal sugar beet pulp conversion was achieved at a concentration of 60 g/l (39% of dry weight) and a bioreactor stirrer speed of 960 rpm. The maximum ethanol yield was 0.1 g ethanol/g of dry weight (0.25 g ethanol/g total sugar content), the efficiency of ethanol production was 49%, and the productivity of the bioprocess was 0.29
Growth and Fermentation Characteristics of Saccharomyces cerevisiae NK28 Isolated from Kiwi Fruit
Lee, Jong-Sub ; Park, Eun-Hee ; Kim, Jung-Wan ; Yeo, Soo-Hwan ; Kim, Myoung-Dong ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1253~1259
DOI : 10.4014/jmb.1307.07050
The influences of glucose concentration, initial medium acidity (pH), and temperature on the growth and ethanol production of Saccharomyces cerevisiae NK28, which was isolated from kiwi fruit, were examined in shake flask cultures. The optimal glucose concentration, initial medium pH, and temperature for ethanol production were 200 g/l, pH 6.0, and
, respectively. Under this growth condition, S. cerevisiae NK28 produced
g/l ethanol in 24 h with a volumetric ethanol production rate of
. S. cerevisiae NK28 was more tolerant to heat and ethanol than laboratory strain S. cerevisiae BY4742, and its tolerance to ethanol and fermentation inhibitors was comparable to that of an ethanologen, S. cerevisiae D5A.
Maximizing Biomass Productivity and
Biofixation of Microalga, Scenedesmus sp. by Using Sodium Hydroxide
Nayak, Manoranjan ; Rath, Swagat S. ; Thirunavoukkarasu, Manikkannan ; Panda, Prasanna K. ; Mishra, Barada K. ; Mohanty, Rama C. ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1260~1268
DOI : 10.4014/jmb.1302.02044
A series of experiments were carried out with three native strains of microalgae to measure growth rates, biomass, and lipid productivities. Scenedesmus sp. IMMTCC-6 had better biomass growth rate and higher lipid production. The growth, lipid accumulation, and carbon dioxide (
) consumption rate of Scenedesmus sp. IMMTCC-6 were tested under different NaOH concentrations in modified BBM. The algal strain showed the maximum specific growth rate (0.474/day), biomass productivity (110.9 mg
consumption rate (208.4 mg
) with an NaOH concentration of 0.005 M on the
day of cultivation. These values were 2.03-, 6.89-, and 6.88-fold more than the algal cultures grown in control conditions (having no NaOH and
fixing efficiency of the microalga with other alternative carbon sources like
was also investigated and compared. The optimized experimental parameters at shake-flask scale were implemented for scaling up the process in a self-engineered photobioreactor. A significant increase in lipid accumulation (14.23% to 31.74%) by the algal strain from the logarithmic to stationary phases was obtained. The algal lipids were mainly composed of
fatty acids, and are desirable for biodiesel production. The study suggests that microalga Scenedesmus sp. IMMTCC-6 is an efficient strain for biodiesel production and
biofixation using stripping solution of NaOH in a cyclic process.
Characterization of Three Antifungal Calcite-Forming Bacteria, Arthrobacter nicotianae KNUC2100, Bacillus thuringiensis KNUC2103, and Stenotrophomonas maltophilia KNUC2106, Derived from the Korean Islands, Dokdo and Their Application on Mortar
Park, Jong-Myong ; Park, Sung-Jin ; Ghim, Sa-Youl ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1269~1278
DOI : 10.4014/jmb.1303.03085
Crack remediation on the surface of cement mortar using microbiological calcium carbonate (
) precipitation (MICP) has been investigated as a microbial sealing agent on construction materials. However, MICP research has never acknowledged the antifungal properties of calcite-forming bacteria (CFB). Since fungal colonization on concrete surfaces can trigger biodeterioration processes, fungi on concrete buildings have to be prevented. Therefore, to develop a microbial sealing agent that has antifungal properties to remediate cement cracks without deteriorative fungal colonization, we introduced an antifungal CFB isolated from oceanic islands (Dokdo islands, territory of South Korea, located at the edge of the East Sea in Korea.). The isolation of CFB was done using B4 or urea-
media. Furthermore, antifungal assays were done using the pairing culture and disk diffusion methods. Five isolated CFB showed
precipitation and antifungal activities against deteriorative fungal strains. Subsequently, five candidate bacteria were identified using 16S rDNA sequence analysis. Crack remediation, fungi growth inhibition, and water permeability reduction of antifungal CFB-treated cement surfaces were tested. All antifungal CFB showed crack remediation abilities, but only three strains (KNUC2100, 2103, and 2106) reduced the water permeability. Furthermore, these three strains showed fungi growth inhibition. This paper is the first application research of CFB that have antifungal activity, for an eco-friendly improvement of construction materials.
Influence of Metal Oxide Particles on Soil Enzyme Activity and Bioaccumulation of Two Plants
Kim, Sunghyun ; Sin, Hyunjoo ; Lee, Sooyeon ; Lee, Insook ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1279~1286
DOI : 10.4014/jmb.1304.04084
Particle size and metal species are important to both soil microbial toxicity and phytotoxicity in the soil ecosystem. The effects of CuO and ZnO nanoparticles (NPs) and microparticles (MPs) on soil microbial toxicity, phytotoxicity, and bioaccumulation in two crops (Cucumis sativus and Zea mays) were estimated in a soil microcosm. In the microcosm system, soil was artificially contaminated with 1,000 mg/kg CuO and ZnO NPs and MPs. After 15 days, we compared the microbial toxicity and phytotoxicity by particle size. In addition, C. sativus and Z. mays were cultivated in soils treated with CuO NPs and ZnO NPs, after which the treatment effects on bioaccumulation were evaluated. NPs were more toxic than MPs to microbes and plants in the soil ecosystem. We found that the soil enzyme activity and plant biomass were inhibited to the greatest extent by CuO NPs. However, in a Biolog test, substrate utilization patterns were more dependent upon metal type than particle size. Another finding indicated that the metal NP uptake amounts of plants depend on the plant species. In the comparison between C. sativus and Z. mays, the accumulation of Cu and Zn by C. sativus was noticeably higher. These findings show that metal oxide NPs may negatively impact soil bacteria and plants. In addition, the accumulation patterns of NPs depend on the plant species.
Biosynthesis of Silver Nanoparticles by Phytopathogen Xanthomonas oryzae pv. oryzae Strain BXO8
Narayanan, Kannan Badri ; Sakthivel, Natarajan ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1287~1292
DOI : 10.4014/jmb.1304.04047
Extracellular biogenic synthesis of silver nanoparticles with various shapes using the rice bacterial blight bacterium Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy, energy dispersive X-ray spectrometry, and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical, with anisotropic structures such as triangles and rods, with an average size of 14.86 nm. The crystalline nature of silver nanoparticles was evident from the bright circular spots in the SAED pattern, clear lattice fringes in the high-resolution TEM images, and peaks in the XRD pattern. The FTIR spectrum showed that biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of the silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environmentally friendly process, which can be used in antimicrobial therapy.
Insight into Norfloxacin Resistance of Acinetobacter oleivorans DR1: Target Gene Mutation, Persister, and RNA-Seq Analyses
Kim, Jisun ; Noh, Jaemin ; Park, Woojun ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1293~1303
DOI : 10.4014/jmb.1307.07059
Antibiotic resistance of soilborne Acinetobacter species has been poorly explored. In this study, norfloxacin resistance of a soil bacterium, Acinetobacter oleivorans DR1, was investigated. The frequencies of mutant appearance of all tested non-pathogenic Acinetobacter strains were lower than those of pathogenic strains under minimum inhibitory concentration (MIC). When the quinolone-resistance-determining region of the gyrA gene was examined, only one mutant (His78Asn) out of 10 resistant variants had a mutation. Whole transcriptome analysis using a RNA-Seq demonstrated that genes involved in SOS response and DNA repair were significantly up-regulated by norfloxacin. Determining the MICs of survival cells after norfloxacin treatment confirmed some of those cells were indeed persister cells. Ten colonies, randomly selected from among those that survived in the presence of norfloxacin, did not exhibit increased MIC. Thus, both the low mutation frequency of the target gene and SOS response under norfloxacin suggested that persister formation might contribute to the resistance of DR1 against norfloxacin. The persister frequency increased without a change in MIC when stationary phase cells, low growth rates conditions, and growth-deficient dnaJ mutant were used. Taken together, our comprehensive approach, which included mutational analysis of the target gene, persister formation assays, and RNA sequencing, indicated that DR1 survival when exposed to norfloxacin is related not only to target gene mutation but also to persister formation, possibly through up-regulation of the SOS response and DNA repair genes.
Inhibition of Microcystis aeruginosa by the Extracellular Substances from an Aeromonas sp.
Liu, Yu-Mei ; Chen, Ming-Jun ; Wang, Meng-Hui ; Jia, Rui-Bao ; Li, Li ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1304~1307
DOI : 10.4014/jmb.1304.04025
Growth of Microcystis aeruginosa could be inhibited significantly within 24 h by the extracellular substances prepared from Aeromonas sp. strain FM. During the treatment, the concentration of extracellular soluble carbohydrates increased significantly in algal culture. Morphological and ultrastructural changes in M. aeruginosa cells, including breakage of the cell surface, secretion of mucilage, and intracellular disorganization of thylakoids, were observed. HPLC-MS analysis showed that the extracellular substances of Aeromonas sp. strain FM were a mixture of free amino acids, tripeptides, and clavulanate. Among these, the algaelysis effects of lysine and clavulanate were confirmed.
Evaluation of Macroporous and Microporous Carriers for CHO-K1 Cell Growth and Monoclonal Antibody Production
Rodrigues, Maria Elisa ; Costa, Ana Rita ; Fernandes, Pedro ; Henriques, Mariana ; Cunnah, Philip ; Melton, David W. ; Azeredo, Joana ; Oliveira, Rosario ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1308~1321
DOI : 10.4014/jmb.1304.04011
The emergence of microcarrier technology has brought a renewed interest in anchorage-dependent cell culture for high-yield processes. Well-known in vaccine production, microcarrier culture also has potential for application in other fields. In this work, two types of microcarriers were evaluated for small-scale monoclonal antibody (mAb) production by CHO-K1 cells. Cultures (5 ml) of microporous Cytodex 3 and macroporous CultiSpher-S carriers were performed in vented conical tubes and subsequently scaled-up (20 ml) to shake-flasks, testing combinations of different culture conditions (cell concentration, microcarrier concentration, rocking methodology, rocking speed, and initial culture volume). Culture performance was evaluated by considering the mAb production and cell growth at the phases of initial adhesion and proliferation. The best culture performances were obtained with Cytodex 3, regarding cell proliferation (average
cells/ml for CultiSpher-S), mAb production (
for CultiSpher-S), and culture longevity (30 days against 10-15 days for CultiSpher-S), probably due to the collagen-coated dextran matrix that potentiates adhesion and prevents detachment. The culture conditions of greater influence were rocking mechanism (Cytodex 3, pulse followed by continuous) and initial cell concentration (CultiSpher-S,
cells/ml). Microcarriers proved to be a viable and favorable alternative to standard adherent and suspended cultures for mAb production by CHO-K1 cells, with simple operation, easy scale-up, and significantly higher levels of mAb production. However, variations of microcarrier culture performance in different vessels reiterate the need for optimization at each step of the scale-up process.
Antifungal Synergy of Theaflavin and Epicatechin Combinations Against Candida albicans
Betts, Jonathan W. ; Wareham, David W. ; Haswell, Stephen J. ; Kelly, Stephen M. ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1322~1326
DOI : 10.4014/jmb.1303.03010
New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024
with theaflavin and 128-256
with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans.
Inhibition of Tumor Growth in a Mouse Xenograft Model by the Humanized Anti-HGF Monoclonal Antibody YYB-101 Produced in a Large-Scale CHO Cell Culture
Song, Seong-Won ; Lee, Song-Jae ; Kim, Chang-Young ; Song, Jae-Kyung ; Jung, Eui-Jung ; Choi, Yong Bock ; Min, Sung-Won ; Oh, Jong-Won ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1327~1338
DOI : 10.4014/jmb.1306.06007
The humanized anti-hepatocyte growth factor (HGF) monoclonal antibody (mAb) YYB-101 is a promising therapeutic candidate for treating various cancers. In this study, we developed a bioprocess for large-scale production of YYB-101 and evaluated its therapeutic potential for tumor treatment using a xenograft mouse model. By screening diverse chemically defined basal media formulations and by assessing the effects of various feed supplements and feeding schedules on cell growth and antibody production, we established an optimal medium and feeding method to produce 757 mg/l of YYB-101 in flask cultures, representing a 7.5-fold increase in titer compared with that obtained under non-optimized conditions. The optimal dissolved oxygen concentration for antibody production was 70%
. A pH shift from 7.2 to 7.0, rather than controlled pH of either 7.0 or 7.2, resulted in productivity improvement in 5 L and 200 L bioreactors, yielding 737 and 830 mg/ml of YYB-101, respectively. The YYB-101 mAb highly purified by affinity chromatography using a Protein A column and two-step ion exchange chromatography effectively neutralized HGF in a cell-based assay and showed potent tumor suppression activity in a mouse xenograft model established with human glioblastoma cells.
Combination of Poly-Gamma-Glutamate and Cyclophosphamide Enhanced Antitumor Efficacy Against Tumor Growth and Metastasis in a Murine Melanoma Model
Kim, Doo-Jin ; Kim, Eun-Jin ; Lee, Tae-Young ; Won, Ji-Na ; Sung, Moon-Hee ; Poo, Haryoung ;
Journal of Microbiology and Biotechnology, volume 23, issue 9, 2013, Pages 1339~1346
DOI : 10.4014/jmb.1306.06071
Conventional chemotherapeutic regimens often accompany severe side effects and fail to induce complete regression of chemoresistant or relapsing metastatic cancers. The need for establishing more efficacious anticancer strategies led to the development of a combined modality treatment of chemotherapy in conjunction with immunotherapy or radiotherapy. It has been reported that poly-gamma-glutamate (
-PGA), a natural polymer composed of glutamic acids, increases antitumor activity by activating antigen-presenting cells and natural killer (NK) cells. Here, we investigated the antitumor effect of
-PGA in combination with cyclophosphamide in a murine melanoma model. Whereas cyclophosphamide alone directly triggered apoptosis of tumor cells in vitro,
-PGA did not show cytotoxicity in tumor cells. Instead, it activated macrophages, as reflected by the upregulation of surface activation markers and the secretion of proinflammatory factors, such as nitric oxide and tumor necrosis factor
. When the antitumor effects were examined in a mouse model, combined treatment with cyclophosphamide and
-PGA markedly suppressed tumor growth and metastasis. Notably,
-PGA treatment dramatically increased the NK cell population in lung tissues, coinciding with decreased metastasis and increased survival. These data collectively suggest that
-PGA can act as an immunotherapeutic agent that exhibits a synergistic antitumor effect in combination with conventional chemotherapy.