The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of nitrogen source for enhanced production of squalene from thraustochytrid Aurantiochytrium sp.
New biotechnology, 2010Co-Authors: Guanqun Chen, Feng Chen, Wai Fan, Tsunehiro Aki, Yue JiangAbstract:Nitrogen (N) sources, the critical medium component, were optimized for squalene production by microalga Aurantiochytrium sp. in heterotrophic cultures. In screening experiments monosodium glutamate, yeast extract and tryptone were found to enhance cell growth and squalene production. The optimal levels of the three nitrogen sources were further determined through central composite experimental design. The squalene content and yield were both influenced not only by monosodium glutamate, tryptone and yeast extract, but also by their interactions. The squalene content and squalene yield were described by the second-order polynomial equations with high confidence levels (>99%). The optimal concentrations of monosodium glutamate, yeast extract and tryptone were predicted to be 6.61 g/L, 6.13 g/L and 4.50 g/L for squalene content and 6.94 g/L, 6.22 g/L and 4.40 g/L for squalene yield, respectively. In the verification experiment, the squalene content and squalene yield reached 0.72 mg/g and 5.90 mg/L, respectively, which were much higher than those obtained in previous studies.
-
Optimization of nitrogen sources for heterotrophic production of eicosapentaenoic acid by the diatom Nitzschia laevis
Enzyme and Microbial Technology, 2001Co-Authors: Zhiyou Wen, Feng ChenAbstract:The nitrogen (N) sources including nitrate, ammonium, urea, tryptone and yeast extract were optimized for eicosapentaenoic acid (EPA) production by the diatom Nitzschia laevis in heterotrophic cultures. First, nitrate and urea were found to be the preferred N sources for both cell growth and EPA content. The optimal concentrations of nitrate and urea for cell growth and EPA yield were 620 mg/liter and 600 mg/liter, respectively. Secondly, tryptone and yeast extract were respectively added to the medium and both of them were found to enhance EPA production compared with the control. To investigate the co-effects of tryptone and yeast extract, in the subsequent experiments, a central composite experimental design was used to optimize the two complex nitrogen sources. The results showed that the EPA production was influenced not only by tryptone or yeast extract, but also by their interactions. The cell dry weight (DW), EPA content and EPA yield could be described by the second-order polynomial equations with high confidence levels (>99%). Based on the surface plots of the responses, the optimal concentrations of tryptone and yeast extract were determined to be 1.6 g/liter and 0.8 g/liter, respectively. To verify the predicted models, the alga was grown in the medium with tryptone and yeast extract at optimal concentrations. The resulting DW, EPA content and EPA yield reached 6.48 g/liter, 2.74% (w/w), and 175 mg/liter, respectively, which agreed with the predicted values, and were much higher than those obtained in the previous studies.
-
Optimization of nitrogen sources for heterotrophic production of eicosapentaenoic acid by the diatom Nitzschia laevis
Enzyme and Microbial Technology, 2001Co-Authors: Zhiyou Wen, Feng ChenAbstract:The nitrogen (N) sources including nitrate, ammonium, urea, tryptone and yeast extract were optimized for eicosapentaenoic acid (EPA) production by the diatom Nitzschia laevis in heterotrophic cultures. First, nitrate and urea were found to be the preferred N sources for both cell growth and EPA content. The optimal concentrations of nitrate and urea for cell growth and EPA yield were 620 mg/liter and 600 mg/liter, respectively. Secondly, tryptone and yeast extract were respectively added to the medium and both of them were found to enhance EPA production compared with the control. To investigate the co-effects of tryptone and yeast extract, in the subsequent experiments, a central composite experimental design was used to optimize the two complex nitrogen sources. The results showed that the EPA production was influenced not only by tryptone or yeast extract, but also by their interactions. The cell dry weight (DW), EPA content and EPA yield could be described by the second-order polynomial equations with high confidence levels (>99%). Based on the surface plots of the responses, the optimal concentrations of tryptone and yeast extract were determined to be 1.6 g/liter and 0.8 g/liter, respectively. To verify the predicted models, the alga was grown in the medium with tryptone and yeast extract at optimal concentrations. The resulting DW, EPA content and EPA yield reached 6.48 g/liter, 2.74% (w/w), and 175 mg/liter, respectively, which agreed with the predicted values, and were much higher than those obtained in the previous studies. © 2001 Elsevier Science Inc. All rights reserved.link_to_subscribed_fulltex
Manu Lopus - One of the best experts on this subject based on the ideXlab platform.
-
Tryptone-stabilized gold nanoparticles induce unipolar clustering of supernumerary centrosomes and G1 arrest in triple-negative breast cancer cells.
Scientific reports, 2019Co-Authors: J. Grace Nirmala, Manu LopusAbstract:Gold nanoparticles of different sizes, shapes, and decorations exert a variety of effects on biological systems. We report a novel mechanism of action of chemically modified, tryptone-stabilized gold nanoparticles (T-GNPs) in the triple-negative breast cancer (TNBC) cell line, MDA-MB-231. The T-GNPs, synthesized using HAuCl4.3H2O and tryptone and characterized by an assortment of spectroscopy techniques combined with high-resolution electron microscopy, demonstrated strong antiproliferative and anti-clonogenic potential against MDA-MB-231 cells, arresting them at the G1 phase of the cell cycle and promoting apoptosis. The molecular mechanism of action of these particles involved induction of unipolar clustering and hyper amplification of the supernumerary centrosomes (a distinctive feature of many tumour cells, including TNBC cells). The clustering was facilitated by microtubules with suppressed dynamicity. Mass spectrometry-assisted proteomic analysis revealed that the T-GNP-induced G1 arrest was facilitated, at least in part, by downregulation of ribosome biogenesis pathways. Due to the presence of supernumerary centrosomes in many types of tumour cells, we propose chemical induction of their unipolar clustering as a potential therapeutic strategy.
-
Tryptone-stabilized gold nanoparticles target tubulin and inhibit cell viability by inducing an unusual form of cell cycle arrest
Experimental cell research, 2017Co-Authors: Tejashree Mahaddalkar, Sourabh Mehta, Sanith Cheriyamundath, H. Muthurajan, Manu LopusAbstract:Gold nanoparticles have been investigated extensively for their molecular mechanisms of action and anticancer potential. We report a novel, tubulin-targeted antiproliferative mechanism of action of tryptone-stabilized gold nanoparticles (TsAuNPs). TsAuNPs, synthesized using HAuCl4·3H2O and tryptone and characterized by a variety of spectroscopic methods and transmission electron microscopy, were found to be inhibitory to viability of human pancreatic (PANC-1), cervical (HeLa), and breast (MDA-MB-231) cancer cell lines in a concentration-dependent manner, with highest efficacy against PANC-1 cells. The particles strongly inhibited the clonogenic propagation of PANC-1 cells. TsAuNPs-mediated inhibition of cell viability involved an unusual mode of cell cycle arrest (arrest at both G0/G1 phase and S-phase) followed by apoptosis. In vitro, TsAuNPs bound purified tubulin, competitively inhibited anilinonaphthalene sulfonate binding to tubulin, and suppressed tubulin assembly. In cells, tubulin-TsAuNPs interactions were manifested as a disrupted microtubule network, defective reassembly of cold-disassembled microtubules, and induction of tubulin acetylation. Our data indicate that TsAuNPs inhibit cell viability by inducing differential cell cycle arrest possibly through disrupted dynamicity of cellular microtubules.
Zhiyou Wen - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of nitrogen sources for heterotrophic production of eicosapentaenoic acid by the diatom Nitzschia laevis
Enzyme and Microbial Technology, 2001Co-Authors: Zhiyou Wen, Feng ChenAbstract:The nitrogen (N) sources including nitrate, ammonium, urea, tryptone and yeast extract were optimized for eicosapentaenoic acid (EPA) production by the diatom Nitzschia laevis in heterotrophic cultures. First, nitrate and urea were found to be the preferred N sources for both cell growth and EPA content. The optimal concentrations of nitrate and urea for cell growth and EPA yield were 620 mg/liter and 600 mg/liter, respectively. Secondly, tryptone and yeast extract were respectively added to the medium and both of them were found to enhance EPA production compared with the control. To investigate the co-effects of tryptone and yeast extract, in the subsequent experiments, a central composite experimental design was used to optimize the two complex nitrogen sources. The results showed that the EPA production was influenced not only by tryptone or yeast extract, but also by their interactions. The cell dry weight (DW), EPA content and EPA yield could be described by the second-order polynomial equations with high confidence levels (>99%). Based on the surface plots of the responses, the optimal concentrations of tryptone and yeast extract were determined to be 1.6 g/liter and 0.8 g/liter, respectively. To verify the predicted models, the alga was grown in the medium with tryptone and yeast extract at optimal concentrations. The resulting DW, EPA content and EPA yield reached 6.48 g/liter, 2.74% (w/w), and 175 mg/liter, respectively, which agreed with the predicted values, and were much higher than those obtained in the previous studies.
-
Optimization of nitrogen sources for heterotrophic production of eicosapentaenoic acid by the diatom Nitzschia laevis
Enzyme and Microbial Technology, 2001Co-Authors: Zhiyou Wen, Feng ChenAbstract:The nitrogen (N) sources including nitrate, ammonium, urea, tryptone and yeast extract were optimized for eicosapentaenoic acid (EPA) production by the diatom Nitzschia laevis in heterotrophic cultures. First, nitrate and urea were found to be the preferred N sources for both cell growth and EPA content. The optimal concentrations of nitrate and urea for cell growth and EPA yield were 620 mg/liter and 600 mg/liter, respectively. Secondly, tryptone and yeast extract were respectively added to the medium and both of them were found to enhance EPA production compared with the control. To investigate the co-effects of tryptone and yeast extract, in the subsequent experiments, a central composite experimental design was used to optimize the two complex nitrogen sources. The results showed that the EPA production was influenced not only by tryptone or yeast extract, but also by their interactions. The cell dry weight (DW), EPA content and EPA yield could be described by the second-order polynomial equations with high confidence levels (>99%). Based on the surface plots of the responses, the optimal concentrations of tryptone and yeast extract were determined to be 1.6 g/liter and 0.8 g/liter, respectively. To verify the predicted models, the alga was grown in the medium with tryptone and yeast extract at optimal concentrations. The resulting DW, EPA content and EPA yield reached 6.48 g/liter, 2.74% (w/w), and 175 mg/liter, respectively, which agreed with the predicted values, and were much higher than those obtained in the previous studies. © 2001 Elsevier Science Inc. All rights reserved.link_to_subscribed_fulltex
Shiow-ling Lee - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of Lipase Production by Burkholderia sp. Using Response Surface Methodology
International journal of molecular sciences, 2012Co-Authors: I-ching Kuan, Shiow-ling LeeAbstract:Response surface methodology (RSM) was employed to optimize the extracellular lipase production by Burkholderia sp. HL-10. Preliminary tests showed that olive oil, tryptone and Tween-80 exhibited significant effects on the lipase production. The optimum concentrations of these three components were determined using a faced-centered central composite design (FCCCD). The analysis of variance revealed that the established model was significant (p < 0.01). The optimized medium containing 0.65% olive oil (v/v), 2.42% tryptone (w/v) and 0.15% Tween-80 (v/v) resulted in a maximum activity of 122.3 U/mL, about three fold higher than that in basal medium. Approximately 99% of validity of the predicted value was achieved.
Y Baek - One of the best experts on this subject based on the ideXlab platform.
-
Optimizing conditions for the growth of Lactobacillus casei YIT 9018 in tryptone-yeast extract-glucose medium by using response surface methodology.
Applied and environmental microbiology, 1995Co-Authors: S Rheem, J Sim, S Kim, Y BaekAbstract:This study was undertaken to find optimum conditions of tryptone, yeast extract, glucose, Tween 80, and incubation temperature for the growth of Lactobacillus casei YIT 9018 and to assess the effects of these factors by use of response surface methodology. A central composite design was used as an experimental design for allocation of treatment combinations. A second-order polynomial regression model, which was used at first for analysis of the experiment, had a significant lack of fit. Therefore, cubic and quartic terms were incorporated into the regression model through variable selection procedures. Effects involving incubation temperature, yeast extract, glucose, and tryptone were significant, whereas the only significant effect involving Tween 80 was the interaction effect between temperature and Tween 80. It turned out that growth of L. casei YIT 9018 was most strongly affected by the incubation temperature. Estimated optimum conditions of the factors for growth of L. casei YIT 9018 are as follows: tryptone, 3.04%; yeast extract, 0.892%; glucose, 1.58%; Tween 80, 0%; incubation temperature, 35 degrees C.
