JBB : Journal of Bioscience and Bioengineering

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Journal of Bioscience and Bioengineering vol.119 cover

Journal of Bioscience and Bioengineering – Recent Articles

  • Dynamics of the microbial community during continuous methane fermentation in continuously stirred tank reactors
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Yue-Qin Tang , Toru Shigematsu , Shigeru Morimura , Kenji Kida

    Methane fermentation is an attractive technology for the treatment of organic wastes and wastewaters. However, the process is difficult to control, and treatment rates and digestion efficiency require further optimization. Understanding the microbiology mechanisms of methane fermentation is of fundamental importance to improving this process. In this review, we summarize the dynamics of microbial communities in methane fermentation chemostats that are operated using completely stirred tank reactors (CSTRs). Each chemostat was supplied with one substrate as the sole carbon source. The substrates include acetate, propionate, butyrate, long-chain fatty acids, glycerol, protein, glucose, and starch. These carbon sources are general substrates and intermediates of methane fermentation. The factors that affect the structure of the microbial community are discussed. The carbon source, the final product, and the operation conditions appear to be the main factors that affect methane fermentation and determine the structure of the microbial community. Understanding the structure of the microbial community during methane fermentation will guide the design and operation of practical wastewater treatments.





  • Identification of glycosyl hydrolases from a metagenomic library of microflora in sugarcane bagasse collection site and their cooperative action on cellulose degradation
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Pattanop Kanokratana , Lily Eurwilaichitr , Kusol Pootanakit , Verawat Champreda

    Lignocellulose decomposition is a natural process involving the cooperative action of various glycosyl hydrolases (GH) on plant cell wall components. In this study, a metagenomic library was constructed to capture the genetic diversity of microbes inhabiting an industrial bagasse collection site. A variety of putative genes encoding GH families 2, 3, 5, 9, 11, and 16 were identified using activity-based screening, which showed low to moderate homology to various cellulases and hemicellulases. The recombinant GH9 endoglucanase (Cel9) and GH11 endo-xylanase (Xyn11) were thermophilic with optimal activity between 75°C and 80°C and the maximal activity at slightly acidic to neutral pH range. The enzymes exhibited cooperative activity with Trichoderma reesei cellulase on the degradation of lignocellulosic substrates. Mixture design showed positive interactions among the enzyme components. The optimal combination was determined to be 41.4% Celluclast, 18.0% Cel9, and 40.6% Xyn11 with the predicted relative reducing sugar of 658% when compared to Celluclast alone on hydrolysis of alkaline-pretreated bagasse. The work demonstrates the potential of lignocellulolytic enzymes from a novel uncultured microbial resource for enhancing efficiency of biomass-degrading enzyme systems for bio-industries.





  • Type 2C protein phosphatase Ptc6 participates in activation of the Slt2-mediated cell wall integrity pathway in Saccharomyces cerevisiae
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Dilruba Sharmin , Yu Sasano , Minetaka Sugiyama , Satoshi Harashima

    The phosphorylation status of cellular proteins results from an equilibrium between the activities of protein kinases and protein phosphatases (PPases). Reversible protein phosphorylation is an important aspect of signal transduction that regulate many biological processes in eukaryotic cells. The Saccharomyces cerevisiae genome encodes 40 PPases, including seven members of the protein phosphatase 2C subfamily (PTC1 to PTC7). In contrast to other PPases, the cellular roles of PTCs have not been investigated in detail. Here, we sought to determine the cellular role of PTC6 in S. cerevisiae with disruption of PTC genes. We found that cells with Δptc6 disruption were tolerant to the cell wall-damaging agents Congo red (CR) and calcofluor white (CFW); however, cells with simultaneous disruption of PTC1 and PTC6 were very sensitive to these agents. Thus, simultaneous disruption of PTC1 and PTC6 gave a synergistic response to cell wall damaging agents. The level of phosphorylated Slt2 increased significantly after CR treatment in Δptc1 cells and more so in Δptc1Δptc6 cells; therefore, deletion of PTC6 enhanced Slt2 phosphorylation in the Δptc1 disruptant. The level of transcription of KDX1 upon exposure to CR increased to a greater extent in the Δptc1Δptc6 double disruptant than the Δptc1 single disruptant. The Δptc1Δptc6 double disruptant cells showed normal vacuole formation under standard growth conditions, but fragmented vacuoles were present in the presence of CR or CFW. Our analyses indicate that S. cerevisiae PTC6 participates in the negative regulation of Slt2 phosphorylation and vacuole morphogenesis under cell wall stress conditions.





  • Production of initial-stage eukaryotic N-glycan and its protein glycosylation in Escherichia coli
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Akkaraphol Srichaisupakit , Takao Ohashi , Ryo Misaki , Kazuhito Fujiyama

    N-Glycosylation is a ubiquitous protein post-translational modification mechanism in eukaryotes. In this work, a synthetic pathway containing glycosyltransferases from Saccharomyces cerevisiae was introduced to Escherichia coli to synthesize lipid-linked mannosyl-chitobiose (Man-GlcNAc2) and trimannosyl-chitobiose (Man3-GlcNAc2). Transfer of Man3-GlcNAc2 onto a model periplasmic protein occurred in the engineered E. coli cell using oligosaccharyltransferase PglB from Campylobacter jejuni. Mass spectrometric analysis of the fluorescently labeled N-glycan indicated a glycan signal composed of 2 HexNAc and 3 Hex residues. The reversed-phase HPLC analysis suggested that the Hex residues were α1,3-, α1,6- and β1,4-linked mannoses. These results indicated that the constructed system synthesizes a Man3-GlcNAc2, identical to that observed in an early eukaryotic dolichol pathway. Finally, glycopeptide mass spectrometry confirmed the transfer of the assembled glycan moiety onto an engineered glycosylation motif of recombinant maltose binding protein. Surprisingly, the Man3-GlcNAc2 structure but not Man-GlcNAc2 was transferred onto maltose binding protein. This work showed that PglB protein might be able to accommodate the transfer of the further engineered glycan with greater complexity.





  • Gene dynamics of core transcription factors for pluripotency in embryonic stem cells
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Brit G. David , Kazuko Okamoto , Taishi Kakizuka , Taro Ichimura , Tomonobu M. Watanabe , Hideaki Fujita

    Embryonic stem cell (ESC) pluripotency is maintained by core transcription factors (TFs). Although the expression of these TFs is well documented, their expression dynamics is poorly evaluated. Here, we visualized the dynamics of Nanog and Oct3/4 expression in ESC using fluorescent reporters and found that expression of these TFs change dramatically during culture.





  • A new aldehyde oxidase catalyzing the conversion of glycolaldehyde to glycolate from Burkholderia sp. AIU 129
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Miwa Yamada , Keika Adachi , Natsumi Ogawa , Shigenobu Kishino , Jun Ogawa , Michihiko Kataoka , Sakayu Shimizu , Kimiyasu Isobe

    We found a new aldehyde oxidase (ALOD), which catalyzes the conversion of glycolaldehyde to glycolate, from Burkholderia sp. AIU 129. The enzyme further oxidized aliphatic aldehydes, an aromatic aldehyde, and glyoxal, but not glycolate or alcohols. The molecular mass of this enzyme was 130 kDa, and it was composed of three different subunits (αβγ structure), in which the α, β, and γ subunits were 76 kDa, 36 kDa, and 14 kDa, respectively. The N-terminal amino acid sequences of each subunit showed high similarity to those of putative subunits of xanthine dehydrogenase. Metals (copper, iron and molybdenum) and chelating reagents (α,α′-dipyridyl and 8-hydroxyquinoline) inhibited the ALOD activity. The ALOD showed highest activity at pH 6.0 and 50°C. Twenty mM glycolaldehyde was completely converted to glycolate by incubation at 30°C for 3 h, suggesting that the ALOD found in this study would be useful for enzymatic production of glycolate.





  • Putative endoglucanase PcGH5 from Phanerochaete chrysosporium is a β-xylosidase that cleaves xylans in synergistic action with endo-xylanase
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Nguyen Duc Huy , Cu Le Nguyen , Jeong-Woo Seo , Dae-Hyuk Kim , Seung-Moon Park

    A predicted endoglucanase gene (PcGH5) was cloned from Phanerochaete chysosporium, and expressed in Pichia pastoris. Although PcGH5 showed similarity with the conserved domains of a cellulase superfamily GH5, a β-glucosidase/6-phospho-β-glucosidase/β-galactosidase superfamily, and an endoglucanase, recombinant PcGH5 exhibited a β-xylosidase activity, rather than endoglucanase activity. Therefore, the predicted gene was named as PcXyl5. Further characterization of recombinant PcXyl5 showed not only catalysis of the hydrolysis of xylo-oligomers to xylose, but also displayed transglycosylation activity using alcohol as a receptor. Optimum pH of rPcXyl5 was found to be 5.5, whereas optimum temperature was 50°C. rPcXyl5 increased reducing sugar release of birchwood xylan, beechwood xylan, and arabinoxylan by 6.4%, 13%, 15.8%, respectively, in synergistic action with endo-xylanase. Interestingly, the late addition of rPcXyl5 into reaction with endo-xylanase resulted in a larger increase of reducing sugar release from pretreated barley straw that addition at the start or by treatment with endo-xylanases alone. The increases observed were 6.3% and 13.8%, respectively, showing a great potential application for hemicellulose saccharification.





  • Comparative study of fungal strains for thermostable inulinase production
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Adriana C. Flores-Gallegos , Juan C. Contreras-Esquivel , Jesús A. Morlett-Chávez , Cristóbal N. Aguilar , Raúl Rodríguez-Herrera

    Fructose and fructo-oligosaccharides (FOS) are important ingredients in the food industry. Fructose is considered an alternative sweetener to sucrose because it has higher sweetening capacity and increases iron absorption in children, and FOS's are a source of dietary fiber with a bifidogenic effect. Both compounds can be obtained by enzymatic hydrolysis of inulin. However, inulin presents limited solubility at room temperature, thus, fructose and FOS production is carried out at 60°C. Therefore, there is a growing interest to isolate and characterize thermostable inulinases. The aim of this work was to evaluate the capacity of different fungal strains to produce potential thermostable inulinases. A total of 27 fungal strains belonging to the genera Aspergillus, Penicillium, Rhizopus, Rhizomucor and Thermomyces were evaluated for production of inulinase under submerged culture using Czapek Dox medium with inulin as a sole carbon source. Strains were incubated at 37°C and 200 rpm for 96 h. Crude enzyme extract was obtained to evaluate inulinase and invertase activity. In order to select the fungal strain with the highest thermostable inulinase production, a selection criterion was established. It was possible to determine the highest inulinase activity for Rhizopus microsporus 13aIV (10.71 U/mL) at 36 h with an optimum temperature of inulinase of 70°C. After 6 h at 60°C, the enzyme did not show any significant loss of activity and retained about 87% activity, while it only retains 57% activity at 70°C. According to hydrolysis products, R. microsporus produced endo and exo-inulinase.





  • Enhanced cellular content and lactate fraction of the poly(lactate-co-3-hydroxybutyrate) polyester produced in recombinant Escherichia coli by the deletion of σ factor RpoN
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Ryosuke Kadoya , Yu Kodama , Ken'ichiro Matsumoto , Seiichi Taguchi

    A new approach at the transcriptional level was applied to lactate-based polyester production. Four σ factor disruptants, ΔrpoN, ΔrpoS, ΔfliA and ΔfecI, of Escherichia coli were used as hosts for poly(lactate-co-3-hydroxybutyrate) production from glucose. Among them, ΔrpoN caused dual positive effects of polymer production, enhanced cellular content and lactate fraction.





  • Lactobacillus plantarum mediated fermentation of Psidium guajava L. fruit extract
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Ravish Bhat , Lakshminarayana Chikkanayakanahalli Suryanarayana , Karunakara Alageri Chandrashekara , Padma Krishnan , Anil Kush , Puja Ravikumar

    Sixteen hour fermentation of the white flesh raw guava Lucknow 49 cultivar using Lactobacillus plantarum NCIM 2912 was taken up for enhancing the antioxidant potential. The fermented guava product with high antioxidant potential, total phenolic content and short and medium chain fatty acids can be used as functional food.





  • Biosorption of cationic basic dye and cadmium by the novel biosorbent Bacillus catenulatus JB-022 strain
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Su Young Kim , Mi Ra Jin , Chang Ho Chung , Yeoung-Sang Yun , Kwang Yeop Jahng , Kang-Yeol Yu

    Biosorption of heavy metals and dyes is a promising technology that involves the removal of toxic metals from industrial wastes. The present study aims to screen the bacterial strains isolated from soils and polluted pond for their potential biosorption of both cationic dye and cadmium. Bacillus catenulatus JB-022 strain removed 58% and 66% of cationic basic blue 3 (BB3) and cadmium (Cd(II)) at the respective concentrations of 2000 mg/L and 150 mg/L. The biosorption equilibrium data were well fitted by the Langmuir adsorption isotherm, and the kinetic studies indicated that the biosorption followed the pseudo-second-order model. The biosorption kinetics showed that the equilibrium was reached within 10 min and 5 min for BB3 and Cd(II), respectively. According to the Langmuir model, the maximum uptakes of BB3 and Cd(II) by the JB-022 biomass were estimated to be 139.74 and 64.28 mg/g, respectively. To confirm the surface morphology and functional groups, field emission scanning electron microscope, energy-dispersive X-ray spectrometer, X-ray diffraction, and Fourier transform infrared spectroscopy analyses were carried out, and the results revealed that the biomass of JB-022 has carboxyl and phosphonate groups as potential surface functional groups capable of binding to cationic pollutants. In conclusion, B. catenulatus JB-022 is proposed as an excellent biosorbent with potentially important applications in removal of cationic pollutants from wastewaters.





  • Effects of culture conditions of Pseudomonas aeruginosa strain RB on the synthesis of CdSe nanoparticles
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Hiroyuki Ayano , Masashi Kuroda , Satoshi Soda , Michihiko Ike

    Cadmium selenide (CdSe) was synthesized by Pseudomonas aeruginosa strain RB in a culture containing lactic acid as a carbon source, 1 mM selenite, and 1 mM cadmium under various conditions. High purity (1.02–1.16 of the atomic ratio of Se to Cd) and efficient synthesis of biogenic CdSe nanoparticles were observed at 25–30°C, 0.05–10 g L−1 NaCl, and neutral pH conditions compared with other tested conditions. However, the size and shape of synthesized CdSe nanoparticles were not changed by changing culture conditions. The contents of S and Se in the particles respectively increased under alkaline and weak acidic conditions. Furthermore, high temperature (>37°C), high salinity (>10 g L−1 NaCl), and alkaline pH affected the CdSe–synthesizing rate by strain RB. This report is the first optimizing the culture conditions for synthesizing biogenic CdSe nanoparticles in a batch processing.





  • Preparation of melanin from Catharsius molossus L. and preliminary study on its chemical structure
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Chao Xin , Jia-hua Ma , Cheng-jia Tan , Zhou Yang , Feng Ye , Chan Long , Shuang Ye , Da-bin Hou

    A great deal of melanin was found in the waste alkali liquor produced by extraction of chitin from Catharsius molossus L. Discarding the lye could harm the environment and cause waste of resources. In this paper, melanin from C. molossus L. was recovered through acid precipitation and purified by pepsin and so on. The purity, chemical composition and structure of the prepared melanin were explored by UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, high resolution 13C Cross polarization magic angle spinning nuclear magnetic resonance spectroscopy pyrolysis gas chromatography mass spectrometry, X ray diffraction, X ray fluorescence, matrix-assisted laser desorption/ionization time of flight tandem mass spectrometry, thermal analysis, and so on. The results showed that the purity of the prepared melanin was higher than the commercial standard melanin and it was a kind of nanoaggregates composed of a large quantity of 5,6-dihydroxyindole eumelanin and a small amount of phaeomelanin. In addition, the prepared melanin was irregular in shape and its structure could be divided into three levels: advanced structure maintained by polypeptides, substructure maintained by the ferric ion and microstructure. In particular, the smallest structural unit showed the graphite-like layered structure containing five layers linked by non-covalent bonds and each layer mainly consisted of 5,6-dihydroxyindole and its derivatives, which might be connected to each other through various chemical bonds.





  • Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Hande Kazak Sarilmiser , Ozlem Ates , Gonca Ozdemir , Kazim Yalcin Arga , Ebru Toksoy Oner

    Levan is a bioactive fructan polymer that is mainly associated with high-value applications where exceptionally high purity requirements call for well-defined cultivation conditions. In this study, microbial levan production by the halophilic extremophile Halomonas smyrnensis AAD6T was investigated systematically. For this, different feeding strategies in fed-batch cultures were employed and fermentation profiles of both shaking and bioreactor cultures were analyzed. Initial carbon and nitrogen source concentrations, production pH, NaCl and nitrogen pulses, nitrogen and phosphorous limitations, trace elements and thiamine contents of the basal production medium were found to affect the levan yields at different extends. Boric acid was found to be the most effective stimulator of levan production by increasing the sucrose utilization three-fold and levan production up to five-fold. This significant improvement implied the important role of quorum sensing phenomenon and its regulatory impact on levan production mechanism. Levan produced by bioreactor cultures under conditions optimized within this study was found to retain its chemical structure. Moreover, its biocompatibility was assessed for a broad concentration range. Hence H. smyrnensis AAD6T has been firmly established as an industrially important resource microorganism for high-quality levan production.





  • Polygonum cuspidatum extracts as bioactive antioxidaion, anti-tyrosinase, immune stimulation and anticancer agents
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Chih-Chen Lee , Yen-Ting Chen , Chien-Chih Chiu , Wei-Ting Liao , Yung-Chuan Liu , Hui-Min David Wang

    In our study, it was applied for the technology of supercritical fluid carbon dioxide extraction to achieve biological constitutes from a Taiwan native plant, Polygonum cuspidatum. We developed bioactive effects of P. cuspidatum extracts via multiple examinations that established bio-purposes at a range of dosage ranges. The research of P. cuspidatum extracts indicated that they possessed anti-oxidative properties on radical-scavenging abilities, reducing activities and metal chelating powers in dose-dependant manners. The extracts also had minor in vitro mushroom tyrosinase suppression and decreased cellular tyrosinase activities and melanin production in B16-F10 cells. Immunologically, P. cuspidatum extracts enhanced the release of tumor necrosis factor α (TNF-α) induced by THP-1 macrophage cell line. In addition, the cell proliferation showed anti-proliferation in dose-dependent manner on human skin melanoma cells, A375 and A375.S2, of the extracts suggesting biological constitutes employed the anti-cancer possessions. This is the first statement presenting bioactivities on P. cuspidatum extracts including anti-oxidation, immune stimulation, anti-tyrosinase and anti-melanoma as far as we know.





  • Characterization of cucumber violaxanthin de-epoxidase gene promoter in Arabidopsis
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Xin Li , Xiaolei Sui , Wenchao Zhao , Hongyu Huang , Yakun Chen , Zhenxian Zhang

    Violaxanthin de-epoxidase (VDE) activates the dissipation of excessive light energy as heat and protects the photosynthetic apparatus from photo-damage. Here we quantitatively analyzed the expression characteristics of cucumber violaxanthin de-epoxidase (CsVDE) promoter using the 1983bp upstream fragment, and a series of 5′-truncated fragments, to drive β-glucuronidase (GUS) expression in Arabidopsis. The activity of CsVDE promoter was altered by hormones and abiotic stresses are positively by indole-3-acetic acid and gibberellin, but negatively by polyethylene glycol, abscisic acid, salicylic acid, mannitol and sodium chloride. Quantitative analysis by fluorometry of GUS activity and histochemical localization showed that the CsVDE promoter is green tissue-specific. A 334bp fragment was sufficient to drive the expression of GUS to the same extent as the longest 1983bp one in green tissue-specific manner. Further analysis of the promoter led to the discovery of one enhancer region and two silencer regions. The activities of GUS driven by the CsVDE promoter fragments were increased when plants were exposed to high light for 4 h, but decreased by 8 h illumination. The high light responsive elements were defined in two positions. The normal-level light-responsive elements were also found in different regions.





  • Titer of trastuzumab produced by a Chinese hamster ovary cell line is associated with tricarboxylic acid cycle activity rather than lactate metabolism
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Yoichi Ishii , Yasufumi Imamoto , Rie Yamamoto , Masayoshi Tsukahara , Kaori Wakamatsu

    Achieving high productivity and quality is the final goal of therapeutic antibody development, but the productivity and quality of antibodies are known to be substantially dependent on the nature of the cell lines expressing the antibodies. We characterized two contrasting cell lines that produce trastuzumab, namely cell line A with a high titer and a low aggregate content and cell line B with a low titer and a high aggregate content to identify the causes of the differences. We observed the following differences: cell growth (A > B), proportion of defucosylated oligosaccharides on antibodies (A < B), and proportion of covalent antibody aggregates (A > B). Our results suggest that the high monoclonal antibody (mAb) titers in cell line A is associated with the high proliferation and is not caused by the lactate metabolism shift (switching from lactate production to net lactate consumption). Rather, these differences can be accounted for by the following: levels of tricarboxylic acid cycle intermediates (A > B), ammonium ion levels (A ≤ B), and oxidative stress (A > B).





  • Islets immunoisolation using encapsulation and PEGylation, simultaneously, as a novel design
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Mohammad Mahdi Nabavimanesh , Sameereh Hashemi-Najafabadi , Ebrahim Vasheghani-Farahani

    The most important obstacle in islets transplantation for the treatment of diabetes is graft rejection by the host immune system. To solve this problem, immunosuppressive drugs should be used, but they may have several side effects. To overcome these problems, islets immunoisolation systems such as encapsulation and PEGylation have been developed. The aim of this study was to investigate the possibility of using encapsulation and PEGylation techniques simultaneously (as a novel design) for immunocamouflaging the islets of Langerhans. For this purpose, the attachment of poly-l-ornithine (PLO) onto the surface of alginate microcapsules and activated methoxy polyethylene glycol (mPEG) onto alginate-PLO microcapsules was verified by Fourier transform infrared analysis and scanning electron microscopy. Viability of the free and encapsulated islets up to the 7th day was approved by acridine orange (AO)/propidium iodide (PI). The obtained results from lymphocytes co-culturing with free and encapsulated islets (in different designs of microcapsules with one to three layers) showed that encapsulation generally reduces the immune response against the islets. However, the addition of PLO and mPEG as second and third layers to the surface of alginate microcapsules decreased interleukine-2 (IL-2) secretion against the islets more and more. Finally, two different activated mPEG, mPEG-succinimidyl carbonate (mPEG-SC) and mPEG-succinimidylvaleric acid (mPEG-SVA), used separately on the surface of microcapsules were investigated, and the results showed that IL-2 secretion was reduced 14.3% and 37.5% in comparison with the alginate-PLO microcapsules, respectively. On the other hand, mPEG-SVA was more effective than mPEG-SC, so it decreased IL-2 secretion 27.1% more than mPEG-SC.





  • Generation of monodisperse cell-sized microdroplets using a centrifuge-based axisymmetric co-flowing microfluidic device
    Publication date: April 2015
    Source:Journal of Bioscience and Bioengineering, Volume 119, Issue 4

    Author(s): Hitoyoshi Yamashita , Masamune Morita , Haruka Sugiura , Kei Fujiwara , Hiroaki Onoe , Masahiro Takinoue

    We report an easy-to-use generation method of biologically compatible monodisperse water-in-oil microdroplets using a glass-capillary-based microfluidic device in a tabletop mini-centrifuge. This device does not require complicated microfabrication; furthermore, only a small sample volume is required in experiments. Therefore, we believe that this method will assist biochemical and cell-biological experiments.





  • Suppression of antibiotic resistance acquisition by combined use of antibiotics
    Publication date: Available online 5 March 2015
    Source:Journal of Bioscience and Bioengineering

    Author(s): Shingo Suzuki , Takaaki Horinouchi , Chikara Furusawa

    We analyzed the effect of combinatorial use of antibiotics with a trade-off relationship of resistance, i.e., resistance acquisition to one drug causes susceptibility to the other drug, and vice versa, on the evolution of antibiotic resistance. We demonstrated that this combinatorial use of antibiotics significantly suppressed the acquisition of resistance.