Publications by authors named "Wenfei Tan"

12 Publications

  • Page 1 of 1

Cloning, expression and biochemical characterization of a novel amidase from Thauera sinica K11.

Protein Expr Purif 2021 Jan 14;177:105751. Epub 2020 Sep 14.

Centre for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China. Electronic address:

A novel amidase (TAM) was identified and cloned from the genome of Thauera sinica K11. The recombinant protein was purified to homogeneity by one-step affinity chromatography for up to 26.4-fold with a yield of 38.1%. Gel filtration chromatography and SDS-PAGE revealed that the enzyme was a tetramer with a subunit of approximately 37.5 kDa. The amidase exhibited the maximum acyl transfer activity at 45 °C and pH 7.0, and it was highly stable over a wide pH range of 6.0-11.0. Inhibition of enzyme activity was observed in the presence of metal ions, thiol reagents and organic solvents. TAM showed a broad substrate spectrum toward aliphatic, aromatic and heterocyclic amides. For linear aliphatic monoamides, the acyl transfer activity of TAM was decreased with the extension of the carbon chain length, and thus the highest activity of 228.2 U/mg was obtained when formamide was used as substrate. This distinct selectivity of amidase to linear aliphatic monoamides expanded the findings of signature amidases to substrate specificity.
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http://dx.doi.org/10.1016/j.pep.2020.105751DOI Listing
January 2021

Thermoresponsive Gigaporous Microspheres Facilitate the Efficient Refolding of Recombinant Nitrilase Inclusion Bodies.

ACS Omega 2020 Jul 15;5(29):17918-17925. Epub 2020 Jul 15.

State Key Laboratory of Heavy Oil Processing, Centre for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.

In order to assist the refolding of recombinant nitrilase inclusion bodies, a series of thermoresponsive media were prepared by grafting poly(-isopropylacrylamide--butyl-methacrylate) [P(NIPAM--BMA)] brushes onto PS microspheres with various particles and pore sizes an atom transfer radical polymerization (ATRP) method. The effects of particle sizes, pore sizes, and brush grafting amounts of thermoresponsive microspheres on nitrilase refolding were investigated preliminarily. The results showed that the PS-P(NIPAM--BMA) microspheres with the medium particle size (74 μm), gigapore size (320 nm), and high grafting amount (35.6 mg/m) were the most effective candidates. The final nitrilase activity yield could be up to 84.5% with a high initial protein concentration (1 mg/mL) at 30 °C, which was 52.5% higher than that of a simple dilution refolding method at the initial protein concentration (0.1 mg/mL). After the refolding process, the PS-P(NIPAM--BMA) microspheres can be easily separated by self-precipitation, and the activity yield of nitrilase still reached 74.5% after being reused for five batches. These results indicated that the thermoresponsive gigaporous medium was an ideal alternative as an artificial chaperone.
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http://dx.doi.org/10.1021/acsomega.0c00432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391251PMC
July 2020

A letter to father

Authors:
Wenfei Tan

Lancet 2020 01;395(10219):e11-e13

Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China

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http://dx.doi.org/10.1016/S0140-6736(19)33100-9DOI Listing
January 2020

Report on the First Nonintubated Robotic-Assisted Thoracic Surgery.

J Cardiothorac Vasc Anesth 2020 02 18;34(2):458-460. Epub 2019 Sep 18.

Department of Thoracic Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, P.R. China. Electronic address:

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http://dx.doi.org/10.1053/j.jvca.2019.09.020DOI Listing
February 2020

Electroacupuncture preconditioning and postconditioning inhibit apoptosis and neuroinflammation induced by spinal cord ischemia reperfusion injury through enhancing autophagy in rats.

Neurosci Lett 2017 03 7;642:136-141. Epub 2017 Feb 7.

Department of Anesthesiology, First Affiliated Hospital, China Medical University, North Nanjing Street, No. 155, Shenyang, Liaoning, PR China.

Electroacupuncture (EA) has beneficial effects on spinal cord ischemia reperfusion (I/R) injury, but the underlying mechanisms are not fully understood. This study aimed to investigate the role of autophagy in the protection of EA preconditioning and postconditioning against spinal cord I/R injury. For this, spinal cord I/R injury was induced by 14min occlusion of the aortic arch, and rats were treated with EA for 20min before or after the surgery. The expression of autophagy components, light chain 3 and Beclin 1, was assessed by Western blot. The hind-limb motor function was assessed using the Basso-Beattie-Bresnahan (BBB) criteria, and motor neurons in the ventral gray matter were counted by histological examination. The apoptosis of neurocyte was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and matrix metalloproteinase-9 (MMP-9) was also measured using Western blot or enzyme-linked immunosorbent assay (ELISA). Either EA preconditioning or postconditioning enhanced autophagy, and minimized the neuromotor dysfunction and histopathological deficits after spinal cord I/R injury. In addition, EA suppressed I/R-induced apoptosis and increased in the expression of TNF-α, IL-1β, and MMP-9. In contrast, the autophagic inhibitor (3-methyladenine, 3-MA) inhibited the neuroprotective effects of EA. Moreover, 3-MA increased the apoptosis and the expression of TNF-α, IL-1β, and MMP-9. In summary, these findings suggested that EA preconditioning and postconditioning could alleviate spinal cord I/R injury, which was partly mediated by autophagy upregulation-induced inhibition of apoptosis and neuroinflammation.
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http://dx.doi.org/10.1016/j.neulet.2017.02.010DOI Listing
March 2017

Prior stressor exposure delays the recovery of surgery-induced cognitive impairment and prolongs neuroinflammation in aged rats.

Brain Res 2016 10 31;1648(Pt A):380-386. Epub 2016 Jul 31.

Department of Anesthesiology, the first Affiliated Hospital of China Medical University, Nanjing North Street 155, Shenyang, Liaoning, China. Electronic address:

Unlabelled: Increasing evidence indicates that stress potentiates pro-inflammatory response to a subsequent peripheral immune challenge. The present study investigated if prior exposure to inescapable tailshock (IS) delayed the recovery of surgery-induced spatial learning and memory impairment and prolonged hippocampus interleukin (IL)-1β and IL-6 expression.

Methods: A total of 192 aged rats were trained with Morris water-maze (MWM) for 6 consecutive days. A single session of inescapable tailshock was performed on day 6 after training. Then, the rats subjected to partial hepatectomy. Hippocampal-dependent spatial learning and memory were assessed on postoperative days 1, 3 and 7. The cytokines IL-1β and IL-6 and ionized calcium binding adaptor protein (Iba)-1 were measured at each time point. Cluster of differentiation 200 (CD200) was also measured to explore potential mechanisms of glial cell activation.

Results: Exposure of IS alone failed to affect the latency to platform and increase hippocampal cytokine levels at each time point. However, IS alone significantly increased the expression levels of Iba-1. A prolonged latency and additional significant increase in hippocampal levels of IL-1β and IL-6 were observed when partial hepatectomy was performed in aged rats exposed to IS 24h later. The combination of IS and surgical trauma dramatically upregulated the levels of Iba-1 and significantly decreased the expression of CD200.

Conclusion: IS alone failed to induce cognitive deficits and increase pro-inflammatory cytokines expression. However, IS delayed the recovery of surgery-induced spatial learning and memory impairment and prolonged pro-inflammatory response to the subsequent surgery challenge.
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http://dx.doi.org/10.1016/j.brainres.2016.07.045DOI Listing
October 2016

Interleukin17A Promotes Postoperative Cognitive Dysfunction by Triggering β-Amyloid Accumulation via the Transforming Growth Factor-β (TGFβ)/Smad Signaling Pathway.

PLoS One 2015 28;10(10):e0141596. Epub 2015 Oct 28.

Department of Pain Medicine, the first Affiliated Hospital of China Medical University, Nanjing North Street 155, Shenyang, Liaoning, China.

Although postoperative cognitive dysfunction (POCD) is relatively common in elderly patients who have undergone major surgery, the mechanisms underlying this postoperative complication are unclear. Previously, we have investigated the role of cytokine-mediated hippocampal inflammation in the development of POCD in a rat model. Here, we sought to determine in mice the role of cytokine interleukin17A (IL17A) in POCD and to characterize the associated signaling pathways. Old mice underwent hepatectomy surgery in the presence or absence of IL17A monoclonal antibody, and cognitive function, hippocampal neuroinflammation, and pathologic markers of Alzheimer's disease (AD) were assessed. We found that the level of IL17A in the hippocampus was increased in hepatectomy mice and that cognitive impairment after surgery was associated with the appearance of certain pathological hallmarks of AD: activation of astrocytes, β-amyloid1-42 (Aβ1-42) production, upregulation of transforming growth factor-β (TGFβ), and increased phosphorylation of signaling mother against decapentaplegic peptide 3 (Smad3) protein in the hippocampus. Surgery-induced changes in cognitive dysfunction and changes in Aβ1-42 and TGFβ/Smad signaling were prevented by the administration of IL17A monoclonal antibody. In addition, IL17A-stimulated TGFβ/Smad activation and Aβ1-42 expression were reversed by IL17A receptor small interfering RNA and a TGFβ receptor inhibitor in cultured astrocytes. Our findings suggest that surgery can provoke IL17A-related hippocampal damage, as characterized by activation of astrocytes and TGFβ/Smad pathway dependent Aβ1-42 accumulation in old subjects. These changes likely contribute to the cognitive decline seen in POCD.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141596PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4624903PMC
June 2016

The effect of rhBMP-2 on pulmonary arterioles remodeling in endotoxin-induced acute lung injury in rats.

Clin Exp Med 2013 Aug 29;13(3):187-92. Epub 2012 Jun 29.

Department of Anesthesiology, First Affiliated Hospital, China Medical University, 155 Nanjing St, Shenyang, 110001, People's Republic of China.

Endotoxin is known to cause acute lung injury (ALI). Here, we investigated the effects and mechanisms of recombinant human bone morphogenetic protein-2 (rhBMP-2) on pulmonary arteriole remodeling in endotoxin-induced ALI in rats. Sixty Wistar rats were randomly divided into 3 groups (n = 20). Control group was infused with normal saline. Lipopolysaccharides (LPS) alone group was infused with LPS. LPS plus rhBMP2 group was infused with rhBMP-2 and LPS. Lung tissue was harvested. The tunica media of the pulmonary arterioles was measured. The expression levels of survivin, p21, cyclin D1, and activated caspase-3 were examined. The proliferation and apoptosis of pulmonary artery smooth muscle cells were evaluated. The tunica media of pulmonary arterioles in LPS alone group was significantly thicker than both that in control and that in LPS plus rhBMP2 groups (P < 0.01). The multiplication rate in LPS alone group was also significantly higher than both that in control and that in LPS plus rhBMP2 groups (P < 0.01). The apoptotic rate in LPS alone group was lower than that in LPS plus rhBMP2 group (P < 0.01). Compared with the control and LPS plus rhBMP2 groups, the expression levels of mRNA and proteins of survivin and cyclin D1 were increased in LPS alone group (P < 0.01), while the expression levels of p21 and activated caspase-3 were decreased (P < 0.01). RhBMP-2 inhibits the remodeling of pulmonary arterioles in endotoxin-induced ALI, which is achieved by enhancing apoptosis and inhibiting proliferation of pulmonary artery smooth muscle cells.
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http://dx.doi.org/10.1007/s10238-012-0197-2DOI Listing
August 2013

Tau hyperphosphorylation is associated with memory impairment after exposure to 1.5% isoflurane without temperature maintenance in rats.

Eur J Anaesthesiol 2010 Sep;27(9):835-41

Department of Anaesthesiology, First Hospital, China Medical University, Shenyang, China.

Background And Objective: There is increasing interest in studying the role of tau hyperphosphorylation associated with memory impairment. We examined the involvement of tau hyperphosphorylation in memory impairment after hypothermia following isoflurane anaesthesia in rats.

Methods: Adult rats were randomly divided into three groups: the control group received no treatment and others were subjected to 1.5% isoflurane anaesthesia with or without temperature control for 2 h. On the day before anaesthesia and on postanaesthetic days 1, 3 and 7, cognitive functions were assessed in a Y-maze test paradigm. To find the relationship between memory results and tau, we measured the site-specific phosphorylation of tau at Thr-205 and Ser-396 and the activity of protein phosphatase 2A within the hippocampus.

Results: The spatial learning and memory of animals with hypothermia were impaired at day 1 after anaesthesia, compared with nonanaesthetized rats. Anaesthesia and hypothermia led to tau hyperphosphorylation at the Thr-205 and Ser-396 epitopes in the hippocampus. There was no significant difference in the protein phosphatase 2A activity between the control and the postanaesthetic rat hippocampal samples, whereas nearly 45% protein phosphatase 2A inhibition was detected in the anaesthetized without temperature maintenance rat samples.

Conclusion: Our results indicate that tau phosphorylation is not a direct result of anaesthesia per se, but it is due to anaesthesia-induced hypothermia and this leads to the inhibition of phosphatase activity as well as tau hyperphosphorylation. Tau hyperphosphorylation is associated with the observed deficits in spatial learning and memory following anaesthesia in hypothermic rats.
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http://dx.doi.org/10.1097/EJA.0b013e32833a6561DOI Listing
September 2010

Towards the stereochemical assignment of natural lydiamycin A.

Chem Commun (Camb) 2010 Jan 14;46(4):574-6. Epub 2009 Dec 14.

Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, University Town of Shenzhen, Xili, Nanshan District, 518055, Shenzhen, China.

A convergent approach leading to the stereoselective synthesis of four diastereomers of lydiamycin A has been established and verified.
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http://dx.doi.org/10.1039/b922544gDOI Listing
January 2010