Browsing by Author "Liu, Ting-Wei"

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Application of aurintricarboxylic acid for the adherence of mouse P19 neurons and primary hippocampal neurons to noncoated surface in serum-free culture
(2012-11-01)
Lee, Tsung-Yih
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Chen, Wen-Shin
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Huang, Yung-An
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Liu, Ting-Wei
;
Hwang, Eric
Dissociated primary neuron culture has been the most widely used model systems for neuroscience research. Most of these primary neurons are cultured on adhesion matrix-coated surface to provide a proper environment for cell anchorage under serum-free conditions. In this study, we provide an alternative technique to promote the adhesions of these neurons using aurintricarboxylic acid (ATA), a nonpeptide compound, without surface manipulations. We first demonstrated that ATA could promote Chinese hamster ovary cell attachment and proliferation in serum-free medium in a dosage-dependent manner. We later showed that ATA significantly enhanced the attachment of the retinoic acid differentiated P19 mouse embryonal carcinoma (P19) neurons, with an optimal concentration around 30 mu g/mL. A similar result was seen in primary hippocampal neurons, with an optimal ATA concentration around 15 mu g/mL. Further morphological assessments revealed that the average neurite length and neuronal polarization were almost identical to that obtained using a conventional method with poly-L-lysine surface. The advantages of using the ATA treatment technique for immunochemical analysis are discussed. (C) 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
High glucose enhances cAMP level and extracellular signal-regulated kinase phosphorylation in Chinese hamster ovary cell: Usage of Br-cAMP in foreign protein beta-galactosidase expression
(2017-07-01)
Lin, Hsiao-Hsien
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Lee, Tsung-Yih
;
Liu, Ting-Wei
;
Tseng, Ching-Ping
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生物科技學系
Glucose is a carbon source for Chinese hamster ovary (CHO) cell growth, while low growth rate is considered to enhance the production of recombinant proteins. The present study reveals that glucose concentrations higher than 1 g/L reduce the growth rate and substantially increase in cAMP (similar to 300%) at a high glucose concentration (10 g/L). High glucose also enhances the phosphorylation of extracellular signal-regulated kinase (ERK) and p27(kiP) by Western blot analysis. To determine whether the phosphorylation of ERK is involved in the mechanism, a cyclic-AMP dependent protein kinase A (PICA) inhibitor (H-8) or MEK (MAPKK) inhibitor (PD98059) was added to block ERK phosphorylation. We show that both the high glucose-induced ERIC phosphorylation and growth rate return to baseline levels. These results suggest that the cAMP/PKA and MAP signaling pathways are involved in the above mentioned mechanism. Interestingly, the direct addition of 8-bromo-cAMP (Br-cAMP), a membrane-permeable cAMP analog, can mimic the similar effects produced by high glucose. Subsequently Br-cAMP could induce beta-galactosidase (beta-Gal) recombinant protein expression by 1.6-fold. Furthermore, Br-cAMP can additionally enhance the (beta-Gal production (from 2.8- to 4.5 fold) when CHO cells were stimulated with glycerol, thymidine, dimethyl sulfoxide, pentanoic acid, or sodium butyrate. Thus, Br-cAMP may be used as an alternative agent in promoting foreign protein expression for CHO cells. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.
Low-Frequency Contact Noise of GaN Nanowire Device Detected by Cross-Spectrum Technique
(2011-06-01)
Li, Liang-Chen
;
Huang, Kuo-Hsun
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Wei, Jia-An
;
Suen, Yuen-Wuu
;
Liu, Ting-Wei
We report the properties of low-frequency contact noise of multielectrode GaN nanowire (NW) devices. A two-port cross-spectrum technique is used to discriminate the noise of the ohmic contact from that of the NW section. The diameter of the GaN NW is around 100 nm. The Ti/Al electrodes of the NWs are defined by e-beam lithography. The typical resistance of a NW section with a length of 800nm is about 5.5 k Omega and the two-wire resistance is below 100 k Omega. The results show that the low-frequency excess noise of the GaN NW is much smaller than that of the current-flowing contact, indicating that the contact noise dominates the noise behavior in our GaN NW devices. A careful study of the noise amplitude (A) of the 1/f noise of different types of NW and carbon nanotube devices, both in our work and in the literature, yields an empirical formula for estimating A from the two-wire resistance of the device. (C) 2011 The Japan Society of Applied Physics