[Show abstract][Hide abstract] ABSTRACT: Diabetes mellitus is a group of complicated metabolic disorders characterized by high blood glucose level and inappropriate insulin secreting capacity due to decreased glucose metabolism and pancreatic β cell mass or dysfunction of β cells. Thus, improving glucose metabolism and preserving β cell mass and function might be useful for the treatment of diabetes. In this study, a novel acidic polysaccharide LBP-s-1 extracted from Lycium barbarum L. was obtained by purification using macroporous resin and ion-exchanged column. Monosaccharide composition analysis indicated that LBP-s-1 was comprised of rhamnose, arabinose, xylose, mannose, glucose, galactose, galacturonic acid in the molar ratio of 1.00:8.34:1.25:1.26:1.91:7.05:15.28. The preliminary structure features of LBP-s-1 were investigated by FT-IR, (1)H NMR and (13)C NMR. In vitro and in vivo hypoglycemic experiments showed that LBP-s-1 had significant hypoglycemic effects and insulin-sensitizing activity through increasing glucose metabolism and insulin secretion and promoting pancreatic β cell proliferation. Preliminary mechanisms were also elucidated.
[Show abstract][Hide abstract] ABSTRACT: Bacillus subtilis was engineered into an efficient hyaluronic acid (HA) producer by introducing two inducible artificial operons carrying HA synthase gene from Pasteurella multocida and precursor genes encoding enzymes involved in synthesis of the sugar precursors. A two-stage induction strategy was established for metabolic engineering of recombinant B. subtilis to efficiently produce uniform HA with controlled molecular weights. Strain TPG223 produced larger HA molecules (yield=6.8g/L; molecular weight=4.5MDa) than strain PG6181 (yield=2.4g/L; molecular weight=13KDa), indicating that the enzymes involved in the synthesis of UDP-glucuronic acid are essential for HA biosynthesis. Strain TPG223 was able to synthesize HA molecules ranging in molecular weight from 8KDa to 5.4MDa indicating that size control is achievable in vivo through appropriate tools. The work reported here not only advanced mechanisms research of size control in vivo, but also could be an attractive alternative for commercial preparation of uniform size-defined HA.
[Show abstract][Hide abstract] ABSTRACT: The molecular backgrounds that determine therapeutic effectiveness in esophageal cancer remain largely unknown. Breast cancer susceptibility gene 1 (BRCA1) expression has been found to switch the response to cisplatin- or paclitaxel-based chemotherapy. It remains unclear how variations in BRCA1 expression influence clinical outcomes in esophageal cancer.
Quantitative real-time polymerase chain reaction (qPCR) was performed to examine BRCA1 mRNA expressions in paraffin-embedded specimens from 144 patients with advanced or metastatic esophageal squamous cell carcinoma who received cisplatin- or docetaxel-based first-line treatments.
Low BRCA1 mRNA expression correlated with increased response rate (RR; P = 0.025 and 0.017, respectively) and median overall survival (mOS; P = 0.002 and P<0.001, respectively) in cisplatin-based chemotherapy or chemoradiotherapy group and also correlated with decreased RR (P = 0.017 and 0.024, respectively) and mOS (both P<0.001) in docetaxel-based chemotherapy or chemoradiotherapy group. Multivariate analysis revealed that low BRCA1 expression was an independent prognostic factor in cisplatin-based chemotherapy (HR 0.29; 95%CI 0.12-0.71; P = 0.007) or chemoradiotherapy (HR 0.12; 95%CI 0.04-0.37; P<0.001) group and higher risk for mortality in docetaxel-based chemotherapy (HR 5.02; 95%CI 2.05-12.28; P<0.001) or chemoradiotherapy (HR 7.02; 95%CI 2.37-27.77; P<0.001) group.
BRCA1 mRNA expression could be used as a predictive and prognostic marker in esophageal cancer who underwent first-line cisplatin- or docetaxel-based treatments.
PLoS ONE 01/2013; 8(1):e52589. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The attachment and proliferation of a well-established, neuron-like cell line, rat pheochromocytoma (PC12) cells, on different extracellular matrices (ECMs) was monitored using cellular impedance sensing (CIS). Commonly used ECMs, including fibronectin, laminin, poly-L: -lysine, collagen and poly-L: -lysine followed by laminin, in addition to DMEM cell culture media alone as a control, were studied: CIS identified the dynamic progress of the adhesion and proliferation of the cells on different ECMs. Among these modified ECM surfaces, the laminin- and poly-L: -lysine/laminin-modified surfaces were the best suited for the neuron-to-electrode surface attachment and proliferation, which was confirmed by MTT assays and a scanning electron microscopy analysis. This work provides a simple method to study neuron cell/ECM interactions in a real-time, label-free, and quantitative manner.
[Show abstract][Hide abstract] ABSTRACT: As a promising type 2 anti-diabetic agent, glucagon-like peptide-1 (GLP-1) is attracting more and more interest. Mutated GLP-1
(mGLP-1) is an analog of native GLP-1. To facilitate the production and purification of mGLP-1, auto-induction and on-column
cleavage was employed in this study. By using auto-induction system, after 24h of shaking culture, about 12.6g wet bacterial
cells could be obtained from 1l medium, and this was about 3.6 times more than that of the IPTG-induction group. After disruption
and centrifugation, the fusion protein was directly purified and cleaved on Ni–Sepharose 6 Fast Flow column. Then, RESOURCE15
RPC column was used for further purification. By using these two steps of purification, about 1.58mg of mGLP-1 with the purity
of up to 98% could be obtained from 1g wet bacterial cells. In the bioactivity study, mGLP-1 displayed a significant and
dose-dependent glucose-lowering activity. These results suggested that auto-induction and on-column cleavage could facilitate
the production and purification of mGLP-1. These methods could also be applied to the preparation of other proteins and peptides.
KeywordsGlucagon-like peptide-1-Auto-induction-On-column cleavage-Expression and purification
World Journal of Microbiology and Biotechnology 09/2010; 26(9):1675-1682. · 1.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To facilitate expression and purification of an analog of GLP-1 (mGLP-1), an intein system was employed in this study. A recombinant fusion protein, CBD-DnaB-mGLP-1, was constructed and expressed in the form of inclusion body. After refolding, the intein-mediated self-cleavage was triggered by pH and temperature shift. By using chitin beads column followed by single step purification, about 2.58 mg of mGLP-1 with the purity of up to 98% could be obtained from 1 L medium. Tricine-SDS-PAGE, RP-HPLC, and ESI-MS were undertaken to determine the purity and molecular weight of mGLP-1. The glucose-lowering activity of mGLP-1 was also preliminarily determined.
Protein and Peptide Letters 05/2010; 17(10):1245-50. · 1.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulation-evoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network’s native state, the precise first-spike latencies in its disinhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways.
Progress in Natural Science 05/2009; 19(5):615–621. · 0.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this paper, we developed a microsphere enhanced and label free high throughput molecular detection based on SPRI and microarray chips, and a self-built surface plasmon resonance imaging instrument was set. One label-free protein chip forming a 7× probe array was designed and fabricated using a commercial microarray robot spotter on chemical modified gold-coated glass slide. Antibody molecules were successfully detected in label-free and high-throughput method by using this chip. The detection signals on the chip was successfully enhanced by using microspheres with a diameter of 1 mum.
[Show abstract][Hide abstract] ABSTRACT: Cell migration is crucial in many physiological and pathological processes including embryonic development, immune response and cancer metastasis. Traditional methods for cell migration detection such as wound healing assay usually involve physical scraping of a cell monolayer followed by an optical observation of cell movement. However, these methods require hand-operation with low repeatability. Moreover, it's a qualitative observation not a quantitative measurement, which is hard to scale up to a high-throughput manner. In this article, a novel and reliable on-chip cell migration detection method integrating surface chemical modification of gold electrodes using self-assembled monolayers (SAMs) and real-time cellular impedance sensing is presented. The SAMs are used to inhibit cell adherence forming an area devoid of cells, which could effectively mimic wounds in a cell monolayer. After a DC electrical signal was applied, the SAMs were desorbed from the electrodes and cells started to migrate. The process of cell migration was monitored by real-time impedance sensing. This demonstrates the first occurrence of integrating cellular impedance sensing and wound-forming with SAMs, which makes cell migration assay being real-time, quantitative and fully automatic. We believe this method could be used for high-throughput anti-migratory drug screening and drug discovery.
Lab on a Chip 07/2008; 8(6):872-8. · 5.70 Impact Factor