JBB : Journal of Bioscience and Bioengineering

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Journal of Bioscience and Bioengineering vol.118 cover

 

Journal of Bioscience and Bioengineering – Recent Articles

  • Purification and characterization of an oxygen-evolving photosystem II from Leptolyngbya sp. strain O-77
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Harutaka Nakamori , Takeshi Yatabe , Ki-Seok Yoon , Seiji Ogo

    A new cyanobacterium of strain O-77 was isolated from a hot spring at Aso-Kuju National Park, Kumamoto, Japan. According to the phylogenetic analysis determined by 16S rRNA gene sequence, the strain O-77 belongs to the genus Leptolyngbya, classifying into filamentous non-heterocystous cyanobacteria. The strain O-77 showed the thermophilic behavior with optimal growth temperature of 55°C. Moreover, we have purified and characterized the oxygen-evolving photosystem II (PSII) from the strain O-77. The O2-evolving activity of the purified PSII from strain O-77 (PSIIO77) was 1275 ± 255 μmol O2 (mg Chl a)−1 h−1. Based on the results of MALDI-TOF mass spectrometry and urea-SDS-PAGE analysis, the purified PSIIO77 was composite of the typical PSII components of CP47, CP43, PsbO, D2, D1, PsbV, PsbQ, PsbU, and several low molecular mass subunits. Visible absorption and 77 K fluorescence spectra of the purified PSIIO77 were almost identical to those of other purified PSIIs from cyanobacteria. This report provides the successful example for the purification and characterization of an active PSII from thermophilic, filamentous non-heterocystous cyanobacteria.





  • Purification and characterization of a novel β-agarase of Paenibacillus sp. SSG-1 isolated from soil
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Tao Song , Yu Cao , Hui Xu , Weijia Zhang , Baojin Fei , Dairong Qiao , Yi Cao

    Agar is a polysaccharide polymer material, generally extracted from seaweed. Most agar degradation strains were isolated from seawater. In order to find new species resources and novel agarase from soil, an agar-degrading bacterium Paenibacillus sp. SSG-1 was isolated from soil. Agarase SSG-1a was purified to homogeneity by 30.2 fold with a yield of 4.8% through ammonium sulfate precipitation, DEAE FF chromatography and native-PAGE separation. The tandem mass spectrometry (MS/MS) results indicated that purified SSG-1a should be a novel β-agarase. The molecular mass of SSG-1a was estimated to be 77 kDa. The optimal temperature and pH for SSG-1a were 50°C and pH 6.0, respectively. Moreover, SSG-1a was stable in pH range of 4.0–10.0 and at temperature up to 40°C. It could hydrolyze the β-1,4 linkage of agarose to produce neoagarohexaose (95 mol%) and neoagarooctaose (5 mol%). Metal ion Mn2+ and reducing reagents (β-Me and DTT) could increase its activity by 150% and 60%, respectively.





  • Incorporation of adenine nucleotide transporter, Ant1p, into proteoliposomes facilitates ATP translocation and activation of encapsulated luciferase
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Akira Nozawa , Yuzuru Tozawa

    We prepared functional luciferase and membrane-integrated form of adenine nucleotide transporter (Ant1p) with a wheat germ cell-free system. The reconstituted Ant1p showed transport activity of ATP/AMP exchange across the membrane. Here we demonstrate that activity of the luciferase entrapped in the Ant1p-proteoliposomes is controllable by the external supply of ATP.





  • Pellicle of thermotolerant Acetobacter pasteurianus strains: Characterization of the polysaccharides and of the induction patterns
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Perumpuli Arachchige Buddhika Niroshie Perumpuli , Taisuke Watanabe , Hirohide Toyama

    Acetobacter species are well known to have the ability to grow floating on the surface of the medium by producing pellicle, which consists of cells and a self-produced matrix of cell-attached polysaccharide. We previously isolated three thermotolerant strains (SL13E-2, SL13E-3, and SL13E-4) from Sri Lankan coconut vinegar and identified all these strains as Acetobacter pasteurianus. The pellicle polysaccharides of these three strains and of A. pasteurianus SKU1108, which was originally isolated from Thailand, were characterized. The monosaccharide composition of the pellicle polysaccharides of these A. pasteurianus strains was found to be varied. For example, the pellicle polysaccharide of SL13E-2 is composed of rhamnose and glucose in the ratio 1:8, and that of SL13E-4 and mesophilic A. pasteurianus NBRC3191 consists of rhamnose, glucose and xylose in the ratio 1:5:2 and 1:4:2, respectively. On the other hand, the pellicle polysaccharides of SL13E-3 and SKU1108 strains are composed of rhamnose, glucose and galactose in the ratio 2:2:1 and 1:5:2.5, respectively. The pellicle formation of thermotolerant SL13E-2, SL13E-3, and SL13E-4 was found to be significantly induced by the addition of ethanol, while poor induction was observed with SKU1108. The size and sugar composition of the polysaccharides obtained from cells induced by ethanol and by uninduced cells were the same, indicating that the number of molecules of the polysaccharides had increased but the polysaccharide molecule remained unchanged. The addition of a sugar source such as glucose, sucrose or fructose slightly induced pellicle formation in SKU1108, especially at 40°C.





  • Improvement of organic solvent tolerance by disruption of the lon gene in Escherichia coli
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Rei Watanabe , Noriyuki Doukyu

    The Lon ATP-dependent protease plays an important role in regulating many biological processes in bacteria. In this study, we examined the organic solvent tolerance of a Δlon mutant of Escherichia coli K-12 and found that the mutant showed remarkably higher organic solvent tolerance than the parent strain. Δlon mutants are known to overproduce capsular polysaccharide, resulting in the formation of mucoid colonies. We considered that this increase in capsular polysaccharide production might be involved in the organic solvent tolerance in E. coli. However, a ΔlonΔwcaJ double-gene mutant displaying a nonmucoid phenotype was as tolerant to organic solvents as the Δlon mutant, suggesting that capsular polysaccharide is not involved in organic solvent tolerance. On the other hand, the Lon protease is known to exhibit proteolytic activity against the transcriptional activators MarA and SoxS, which can enhance the expression level of the AcrAB-TolC efflux pump. We found that the Δlon mutant showed a higher expression level of AcrB than the parent strain. In addition, the ΔlonΔacrB double-gene mutant showed a significant decrease in organic solvent tolerance. Thus, it was shown that organic solvent tolerance in the Δlon mutant depends on the AcrAB-TolC pump but not capsular polysaccharide. E. coli strain JA300 acrRIS marR overexpresses the AcrAB-TolC pump and exhibits high-level solvent tolerance. In an attempt to further improve the solvent tolerance of JA300 acrRIS marR, a lon gene disruptant of this strain was constructed. However, the resulting mutant JA300 acrRIS marR Δlon showed lower solvent tolerance than JA300 acrRIS marR.





  • Production and characterization of medium-chain-length polyhydroxyalkanoates by Pseudomonas mosselii TO7
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Yi-Jr Chen , Yan-Chia Huang , Chia-Yin Lee

    The polyhydroxyalkanoate (PHA) production and growth of Pseudomonas mosselii TO7, a newly isolated Pseudomonas species from the wastewater of a vegetable oil manufacturing facility, was analyzed. Phenotypic analysis and phylogenetic analysis of the 16S rRNA gene revealed that it is closely related to Pseudomonas mosselii. In the presence of palm kernel and soybean oils, P. mosselii TO7 produced up to 50% cell dry weight (CDW) medium-chain-length (MCL) PHAs comprising high poly(3-hydroxyoctanoate) (P(3HO)) content; P(3HO) content increased to 45% CDW when grown in octanoate using a single-step culture process. The PHA monomer was identified by 13C nuclear magnetic resonance spectroscopy. The average molecular weight and polydispersity index of PHA were 218.30 ± 31.73 and 2.21 ± 0.18, respectively. The PHA produced by P. mosselii TO7 in the presence of palm kernel oil had two melting temperature (T m) values of 37.2°C and 55.7°C with melting enthalpy (ΔH m) values of 51.09 J g−1 and 26.57 J g−1, respectively. Inhibition analyses using acrylic and 2-bromooctanoic acids revealed β-oxidation as the primary pathway for MCL-PHA biosynthesis using octanoic acid. Moreover, Pseudomonas putida GPp104 PHA, harboring the PHA synthase genes of P. mosselii (phaC1pm and phaC2pm) was used for heterologous expression, which demonstrated that phaC1pm is the main PHA synthesis enzyme, and 3-hydroxyoctanoyl-CoA is its major substrate. This was the first report of a P. mosselii TO7 isolate producing high-yield P(3HO) through utilization of plant oils.





  • Isolation of potential probiotic Lactobacillus oris HMI68 from mother's milk with cholesterol-reducing property
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Marimuthu Anandharaj , Balayogan Sivasankari

    The objective of this study was to evaluate the probiotic properties of Lactobacillus strains isolated from mother's milk and their effects on cholesterol assimilation. In this study 120 isolates from mother's milk were phenotypically and genotypically characterized. Among these, only 6 predominant strains were identified as Lactobacillus spp. The following parameters were selected as important test variables in model stomach passage survival trials: acid and bile tolerance, antimicrobial activity, antibiotic susceptibility and cholesterol reduction. Results showed that the considerable variation existed among six strains. Moreover, the strain HMI68 is the most acid-tolerant and the HMI28 and HMI74 is the most acid-sensitive of all strains tested. HMI118 did not grow at 0.5% and 1% bile concentration after 5 h but the HMI68 and HMI43 showed some tolerance to such bile concentration. The differences found in the growth rate were not significant (P > 0.05). HMI68 showed resistance to most of the antibiotics as well as antagonistic activity against the tested pathogens. The amount of cholesterol reduction is increased when the media supplemented with bile salts. HMI68 assimilate 61.05 ± 0.05 μg/ml cholesterol with the presence of 0.3% bile salt this could be significantly decreased by 25.41 ± 1.09 μg/ml without bile salt. HMI68 was identified to be Lactobacillus oris HMI68 and 16S rRNA sequence was deposited in the National Center for Biotechnological Information (GenBank). For the first time the cholesterol-reducing property of L. oris isolated from mother's milk were investigated in this study. Therefore the effective L. oris HMI68 strain was regarded as a candidate probiotic.





  • Enrichment of amino acid-oxidizing, acetate-reducing bacteria
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Makoto Ato , Masaharu Ishii , Yasuo Igarashi

    In anaerobic condition, amino acids are oxidatively deaminated, and decarboxylated, resulting in the production of volatile fatty acids. In this process, excess electrons are produced and their consumption is necessary for the accomplishment of amino acid degradation. In this study, we anaerobically constructed leucine-degrading enrichment cultures from three different environmental samples (compost, excess sludge, and rice field soil) in order to investigate the diversity of electron-consuming reaction coupled to amino acid oxidation. Constructed enrichment cultures oxidized leucine to isovalerate and their activities were strongly dependent on acetate. Analysis of volatile fatty acids (VFAs) profiles and community structure analysis during batch culture of each enrichment indicated that Clostridium cluster I coupled leucine oxidation to acetate reduction in the enrichment from the compost and the rice field soil. In these cases, acetate was reduced to butyrate. On the other hand, Clostridium cluster XIVb coupled leucine oxidation to acetate reduction in the enrichment from the excess sludge. In this case, acetate was reduced to propionate. To our surprise, the enrichment from rice field soil oxidized leucine even in the absence of acetate and produced butyrate. The enrichment would couple leucine oxidation to reductive butyrate synthesis from CO2. The coupling reaction would be achieved based on trophic link between hydrogenotrophic acetogenic bacteria and acetate-reducing bacteria by sequential reduction of CO2 and acetate. Our study suggests anaerobic degradation of amino acids is achieved yet-to-be described reactions.





  • Statistical analysis of sake-preparation conditions and dimethyl trisulfide formation
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Kei Sasaki , Nahoko Nishibori , Muneyoshi Kanai , Atsuko Isogai , Osamu Yamada , Nami Goto-Yamamoto , Tsutomu Fujii

    Dimethyl trisulfide (DMTS) is known to be responsible for hineka, an off-flavor that develops during storage, in sake. Previous studies have attempted to elucidate the mechanism of DMTS formation during sake storage, but the mechanism underlying DMTS formation remains unclear. In this study, we determined the sake-preparation conditions that affect DMTS formation. We analyzed 76 sake samples immediately after filtration, which were donated by sake-producing companies. We measured the DMTS concentration in sake after 7 days of storage at 70°C (DMTS-pp) using gas chromatography/mass spectrometry. In the statistical analysis, DMTS-pp was set as the objective variable, whereas the preparation conditions and analytical results for sake were set as the explanatory variables. We used multiple linear regression (MLR) analysis with a stepwise method and partial least squares regression (PLSR) to analyze the data. The statistical analysis showed that the significant factors for DMTS-pp were the average temperature in the moromi mash (Temp ave), the total daily temperature in the moromi mash (Temp sum), the concentration of sulfur-containing amino acids in sake, and the Zn concentration in sake. These factors explained 63.4% of the variance in DMTS-pp according to the MLR analysis and 64.2% according to the PLSR analysis. Further MLR analysis showed that Temp ave in early stage and Temp sum in later stage were important factors for DMTS-pp. This result suggests that the rice dissolution caused by high Temp ave in early stage and yeast cell lysis caused by high Temp sum in later stage contribute to high DMTS-pp.





  • Functional analysis of histone deacetylase and its role in stress response, drug resistance and solid-state cultivation in Aspergillus oryzae
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Moriyuki Kawauchi , Kazuhiro Iwashita

    In the eukaryotic cell, histone deacetylases (HDACs) play key roles in the regulation of fundamental cellular process such as development regulation, stress response, secondary metabolism and genome integrity. Here, we provide a comprehensive phenotypic analysis using HDAC disruptants in Aspergillus oryzae. Our study revealed that four HDACs, hdaA/Aohda1, hdaB/Aorpd3, hdaD/Aohos2 and hst4/AohstD were involved in stress response, cell wall synthesis and chromatin integrity in A. oryzae. Osmotic stress sensitivity of HDAC disruptants differed between plate cultures and liquid cultures, suggesting that HDACs adapt to the difference environmental conditions. Using a common A. oryzae fermentation medium, rice-koji, we also characterized HDACs related to growth and enzyme production to investigate which HDACs will be required for adaptation to environmental conditions and stress resistances. Because HDACs are widely conserved, our study has broad applications and may inform work with filamentous fungi and other eukaryote.





  • In-package atmospheric pressure cold plasma treatment of cherry tomatoes
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Nrusimha Nath Misra , Kevin M. Keener , Paula Bourke , Jean-Paul Mosnier , Patrick J. Cullen

    Cold plasma is increasingly under research for decontamination of foods, especially fresh fruits and vegetables. The effect of cold plasma on food quality, however, remains under researched. This study investigates the effects of cold plasma generated within a sealed package from a dielectric barrier discharge on the physical quality parameters and respiration rates of cherry tomatoes. Respiration rates and weight loss were monitored continuously, while other parameters are reported at the end of storage period. Differences among weight loss, pH and firmness for control and treated cherry tomatoes were insignificant towards the end of storage life. Changes in respiration rates and colour of tomatoes were recorded as a function of treatment, which were not drastic. The results implicate that cold plasma could be employed as a means for decontamination of cherry tomatoes while retaining product quality.





  • Production of a biodegradable plastic-degrading enzyme from cheese whey by the phyllosphere yeast Pseudozyma antarctica GB-4(1)W
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Takashi Watanabe , Yukiko Shinozaki , Ken Suzuki , Motoo Koitabashi , Shigenobu Yoshida , Yuka Sameshima-Yamashita , Hiroko Kuze Kitamoto

    Cheese whey is a by-product of cheese production and has high concentrations of lactose (about 5%) and other nutrients. Pseudozyma antarctica produces a unique cutinase-like enzyme, named PaE, that efficiently degrades biodegradable plastics. A previous study showed that a combination of 1% oil and 0.5% lactose increased cutinase-like enzyme production by another species of yeast. In this study, to produce PaE from cheese whey, we investigated the effects of soybean oil on PaE production (expressed as biodegradable plastic-degrading activity) by P. antarctica growing on lactose or cheese whey. In flask cultures, the final PaE activity was only 0.03 U/ml when soybean oil was used as the sole carbon source, but increased to 1.79 U/ml when a limited amount of soybean oil (under 0.5%) was combined with a relatively high concentration of lactose (6%). Using a 5-L jar fermentor with lactose fed-batch cultivation and periodic soybean oil addition, about 14.6 U/ml of PaE was obtained after 5 days of cultivation. When the lactose was replaced with cheese whey, PaE production was 10.8 U/ml after 3 days of cultivation.





  • Biosynthesis of 1,3-propanediol from glycerol with Lactobacillus reuteri: Effect of operating variables
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Jyotsna Jolly , Bernd Hitzmann , Subramanian Ramalingam , Kadathur B. Ramachandran

    Chemical synthesis of 1,3-propanediol (1,3-PD) is environmentally unfriendly and hence its microbial production is preferred, especially for biomedical, cosmetic and textile applications. In this work, production of 1,3-PD by co-fermentation of glucose and glycerol by Lactobacillus reuteri was investigated under different cultivation conditions such as aeration, acetate concentration and different molar ratios of glucose/glycerol. The final concentration of 1,3-PD and yield attained under unaerated conditions was close to that obtained under anaerobic conditions. Addition of acetate in the initial medium at 5 g/l increased the productivity of 1,3-PD but above this concentration it was found to be inhibitory. Batch reactor experiments showed that the molar ratio of glucose and glycerol in the medium affected the fermentation pattern. The effect of molar ratios was further investigated in fed-batch fermentation and the optimum ratio was found to be 1.5. In repeated fed-batch fermentation with co-feeding of glucose and glycerol in the molar ratio of 1.5, 1,3-PD concentration reached up to 65.3 g/l, which is the highest 1,3-PD concentration reported so far for this strain. The yield (0.97 mol/mol) based on glycerol utilized also approached the theoretical value (1 mol/mol).





  • Application of airlift bioreactor for the cultivation of aerobic oleaginous yeast Rhodotorula glutinis with different aeration rates
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Hong-Wei Yen , Yi Xian Liu

    The high cost of microbial oils produced from oleaginous microorganisms is the major obstacle to commercial production. In this study, the operation of an airlift bioreactor is examined for the cultivation of oleaginous yeast-Rhodotorula glutinis, due to the low process cost. The results suggest that the use of a high aeration rate could enhance cell growth. The maximum biomass concentration of 25.40 g/L was observed in the batch with a 2.0 vvm aeration rate. In addition, a higher aeration rate of 2.5 vvm could achieve the maximum growth rate of 0.46 g/L h, about twice the 0.22 g/L h obtained in an agitation tank. However, an increase in tank pressure instead of the aeration rate did not enhance cell growth. The operation of airlift bioreactor described in this work has the advantages of simple operation and low energy consumption, thus making it suitable for the accumulation of microbial oils.





  • Microcompartmentalized cell-free protein synthesis in semipermeable microcapsules composed of polyethylenimine-coated alginate
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Daisuke Saeki , Shinji Sugiura , Toshiyuki Kanamori , Seigo Sato , Sosaku Ichikawa

    We describe microcompartmentalized cell-free protein synthesis in semipermeable microcapsules prepared from water-in-oil-in-water droplets by a rupture-induced encapsulation method. An aqueous solution of template DNA coding for green fluorescent protein and enzymes for the cell-free protein synthesis was aliquoted into water-in-oil droplets using a microfluidic device, and the droplets were transformed into semipermeable microcapsules. Substrates for protein synthesis diffused into the microcapsules through their semipermeable polyion complex membranes composed of polyethylenimine-coated alginate. Cell-free protein synthesis was confirmed by detection of the fluorescence of the synthesized green fluorescence protein in the microcapsules. We also used this microcompartmentalized system to synthesize protein from a single molecule of template DNA encapsulated by limiting dilution.





  • Robust in vitro assay system for quantitative analysis of parasitic root-knot nematode infestation using Lotus japonicus
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Arshana N.N. Amin , Shuhei Hayashi , Derek G. Bartlem

    Root-knot nematodes are sedentary endoparasites that induce permanent infestation sites inside the roots of a broad range of crop plants. The development of effective control strategies require understanding the root-knot nematode parasitic process, however, the key molecular determinants for host manipulation during infestation remain elusive. One limiting factor has been the lack of a standardized conventional method for quantitative measurement of host parasitism by root-knot nematodes, particularly one that enables efficient downstream analyses and is free from other biological sources of variability. We report here a robust, highly reproducible system for quantitative analysis of all stages of root-knot nematode infestation using the legume Lotus japonicus as the plant host. This system provides a high quality nematode inoculum that maintains consistency in juvenile age and viability even between independently prepared populations. An optimized root transformation protocol was also developed for L. japonicus to facilitate downstream molecular studies in conjunction with the quantitative assay. Hairy root transformation efficiencies up to 91% were achieved. Root-knot nematodes formed egg masses at the root surface of both intact plants and transgenic hairy root cultures within eight weeks, confirming the assay conditions support an efficient completion of the infestation cycle. The in vitro assay system described here is compatible with other plant hosts and will benefit agricultural biotechnology research as it now enables specific high-throughput screening of nematode resistance traits together with subsequent mechanistic elucidation of the causative factors.





  • Observation of ovarian cancer stem cell behavior and investigation of potential mechanisms of drug resistance in three-dimensional cell culture
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Junsong Chen , Jing Wang , Yunxia Zhang , Dengyu Chen , Cuiping Yang , Cai Kai , Xiaoying Wang , Fangfang Shi , Jun Dou

    Cancer cells behave differently in a three-dimensional (3D) cell culture compared with in the conventional two-dimensional (2D) one. Accumulated evidences indicate that the characteristics of cancer stem cells (CSCs) are different from common cancer cells due to their ability to produce tumors and resist chemoradiation. The objective of this work was to observe CSC behavior and investigate the potential mechanisms of CSC drug resistance in 3D versus 2D in vitro environment. We first demonstrated that the CD44+CD117+cells isolated from the human epithelial ovarian cancer HO8910 cell line have the properties of CSCs that revealed faster growth, larger tumorsphere and stronger survival potential in the hypoxic environment in 3D cell culture as well as more powerful tumorigenicity in a xenograft mice than the HO8910 cells. The CD44+CD117+CSCs also exhibited high chemoresistance to anticancer drugs when the cells were incubated with 5-fluorouracil, cisplatin and carboplatin, respectively in 3D versus 2D environment. This might be associated with the high expression of ABCG2, ABCB1 and the high expression of MMP-2 and MMP-9 in CD44+CD117+CSCs. Overall, these results suggest the advantages of using 3D culture model to accurately display CSC behavior in vitro. 3D model may improve the efficacy of screening anticancer drugs for treatment of ovarian CSCs.





  • Efficient folding/assembly in Chinese hamster ovary cells is critical for high quality (low aggregate content) of secreted trastuzumab as well as for high production: Stepwise multivariate regression analyses
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Yoichi Ishii , Junko Murakami , Kazue Sasaki , Masayoshi Tsukahara , Kaori Wakamatsu

    When developing cell culture processes for therapeutic antibodies, the low content of aggregated proteins is the most critical because administering aggregated antibody molecules might result in adverse effects such as immunogenicity. To characterize cells with high productivity and quality, we determined factors that are closely related to antibody titer, which is a productivity indicator, and the area percentage of high molecular weight species in cultivated media, which is equivalent to aggregate content and is used as a quality indicator. We examined the factors influencing antibody titer and aggregate content using various data from 28 cell lines throughout their culture periods from growth to death phases. Our study using correlation analysis revealed that statistically significant correlations between factors and indicators changes with sampling points, hence we thought that various factors would influence each indicator simultaneously. To understand the relationship between these factors and titer/aggregates contents, we performed stepwise multiple linear regression analyses and deduced a multiple linear model for each indicator. The titer was found to positively associate with specific growth rate and specific production rate and negatively with intracellular heavy chain content. The aggregate content was found to positively associate with protein disulfide isomerase mRNA level and negatively with light chain secreted into culture media, specific production rate, intracellular light chain content, and specific growth rate. Our observations suggest that correct and efficient assembling and/or folding of an antibody molecule in an endoplasmic reticulum are important for high titer and low aggregates contents.





  • Olfactory ensheathing cells seeded muscle-stuffed vein as nerve conduit for peripheral nerve repair: A nerve conduction study
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Yogeswaran Lokanathan , Min-Hwei Ng , Shariful Hasan , Anuar Ali , Mazzre Mahmod , Ohnmar Htwe , Sharifah Ahmad Roohi , Ruszymah Bt Hj Idrus , Shalimar Abdullah , Amaramalar Selvi Naicker

    We evaluated bridging of 15 mm nerve gap in rat sciatic nerve injury model with muscle-stuffed vein seeded with olfactory ensheathing cells as a substitute for nerve autograft. Neurophysiological recovery, as assessed by electrophysiological analysis was faster in the constructed biological nerve conduit compared to that of autograft.





  • Neuroprotective effect of the fermented Gumiganghwal-tang
    Publication date: August 2014
    Source:Journal of Bioscience and Bioengineering, Volume 118, Issue 2

    Author(s): Bo-Ra Yun , Jin Bae Weon , Jiwoo Lee , Min Rye Eom , Choong Je Ma

    Gumiganghwal-tang (GT) is a traditional herbal prescription widely used to treat inflammatory diseases in Asia. In this study, we evaluated neuroprotective effect and acetylcholinesterase (AChE) inhibitory activity of GT and compared with fermented GT (FGT). In order to better understand the neuroprotective mechanism, intracellular reactive oxygen species (ROS) production was investigated and high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis of contents of GT and FGT were conducted. As a result, FGT showed more potent protective effect against glutamate-induced HT22 cell death than GT and inhibited AChE activity. The neuroprotective effect of FGT is associated with inhibition of ROS production. The HPLC-DAD analytical results indicated that FGT contains higher content of bergapten and atractylenolide III than that of GT. In conclusion, FGT have neuroprotective effect and AChE inhibition, and may be useful source for treatment of neurodegenerative disease.