Publications by authors named "Shuang Yin"

38 Publications

Cost-effective purification process development for chimeric hepatitis B core (HBc) virus-like particles assisted by molecular dynamic simulation.

Eng Life Sci 2021 Jun 3;21(6):438-452. Epub 2021 May 3.

School of Chemical Engineering & Advanced Materials, Faculty of Engineering, Computer and Mathematical Sciences University of Adelaide Adelaide SA Australia.

Inserting foreign epitopes to hepatitis B core (HBc) virus-like particles (VLPs) could influence the molecular conformation and therefore vary the purification process. In this study, a cost-effective purification process was developed for two chimeric HBc VLPs displaying Epstein-Barr nuclear antigens 1 (EBNA1), and hepatitis C virus (HCV) core. Both chimeric VLPs were expressed in soluble form with high production yields in . Molecular dynamic (MD) simulation was employed to predict the stability of chimeric VLPs. HCV core-HBc was found to be less stable in water environment compared with EBNA1-HBc, indicating its higher hydrophobicity. Assisting with MD simulation, ammonium sulfate precipitation was optimized to remove host cell proteins with high target protein recovery yields. Moreover, 99% DNA impurities were removed using POROS 50 HQ chromatography. In characterization measurement, we found that inserting HCV core epitope would reduce the ratio of α-helix of HCV core-HBc. This could be another reason on the top of its higher hydrophobicity predicted by MD simulation, causing its less stability. Tertiary structure, transmission electron microscopy, and immunogenicity results indicate that two chimeric VLPs maintained correct VLP structure ensuring its bioactivity after being processed by the developed cost-effective purification approach.
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http://dx.doi.org/10.1002/elsc.202000104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8182290PMC
June 2021

Engineered Human Heavy-Chain Ferritin with Half-Life Extension and Tumor Targeting by PAS and RGDK Peptide Functionalization.

Pharmaceutics 2021 Apr 9;13(4). Epub 2021 Apr 9.

School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide SA5005, Australia.

Ferritin, one of the most investigated protein nanocages, is considered as a promising drug carrier because of its advantageous stability and safety. However, its short half-life and undesirable tumor targeting ability has limited its usage in tumor treatment. In this work, two types of functional peptides, half-life extension peptide PAS, and tumor targeting peptide RGDK (Arg-Gly-Asp-Lys), are inserted to human heavy-chain ferritin (HFn) at C-terminal through flexible linkers with two distinct enzyme cleavable sites. Structural characterizations show both HFn and engineered HFns can assemble into nanoparticles but with different apparent hydrodynamic volumes and molecular weights. RGDK peptide enhanced the internalization efficiency of HFn and showed a significant increase of growth inhibition against 4T1 cell line in vitro. Pharmacokinetic study in vivo demonstrates PAS peptides extended ferritin half-life about 4.9 times in Sprague Dawley rats. RGDK peptides greatly enhanced drug accumulation in the tumor site rather than in other organs in biodistribution analysis. Drug loaded PAS-RGDK functionalized HFns curbed tumor growth with significantly greater efficacies in comparison with drug loaded HFn.
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http://dx.doi.org/10.3390/pharmaceutics13040521DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070472PMC
April 2021

Stability of Engineered Ferritin Nanovaccines Investigated by Combined Molecular Simulation and Experiments.

J Phys Chem B 2021 04 7;125(15):3830-3842. Epub 2021 Apr 7.

School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, South Australia 5005, Australia.

Human ferritin is regarded as an attractive and promising vaccine platform because of its uniform structure, good plasticity, and desirable thermal and chemical stabilities. Besides, it is biocompatible and presumed safe when used as a vaccine carrier. However, there is a lack of knowledge of how different antigen insertion sites on the ferritin nanocage impact the resulting protein stability and performance. To address this question, we selected Epstein-Barr nuclear antigen 1 as a model epitope and fused it at the DNA level with different insertion sites, namely, the N- and C-termini of ferritin, to engineer proteins E1F1 and F1E1, respectively. Protein properties including hydrophobicity and thermal, pH, and chemical stability were investigated both by molecular dynamics (MD) simulation and by experiments. Both methods demonstrate that the insertion site plays an important role in protein properties. The C-terminus insertion (F1E1) leads to a less hydrophobic surface and more tolerance to the external influence of high temperature, pH, and high concentration of chemical denaturants compared to N-terminus insertion (E1F1). Simulated protein hydrophobicity and thermal stability by MD were in high accordance with experimental results. Thus, MD simulation can be used as a valuable tool to engineer nanovaccine candidates, cutting down costs by reducing the experimental effort and accelerating vaccine design.
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http://dx.doi.org/10.1021/acs.jpcb.1c00276DOI Listing
April 2021

MiR-125b acts as a tumor suppressor of melanoma by targeting NCAM.

J BUON 2021 Jan-Feb;26(1):182-188

Department of Plastic and Aesthetic Surgery, the Fourth Affiliated Hospital of Harbin Medical University, Harbin, China.

Purpose: To investigate the effects of micro ribonucleic acid (miR)-125b on the growth and apoptosis of malignant melanoma (MM) cells and related mechanisms.

Methods: The differences in the expressions of miR-125b and neural cell adhesion molecule-120 (NCAM-120), NCAM-140 and NCAM-180 in 5 cases of MM tissues (MM group) and corresponding adjacent tissues (Paracancer group) as well as MM cells were detected via quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry, respectively. Next, malignant melanoma A375 cells were selected to exogenously overexpress miR-125 (miR-125 mimic group). Then, in vitro functional assays were conducted to determine the influences of miR-125b on the proliferation, migration and apoptosis of MM cells, and the changes in the binding of miR-125b to the 3'-untranslated region (3'-UTR) of wild-type and mutant NCAM messenger RNAs (mRNAs) were verified using dual-luciferase assay.

Results: MiR-125b was significantly lowly expressed in MM tissues and cells (p<0.01), while NCAM-120, NCAM-140 and NCAM-180 were clearly highly expressed in MM tissues and cells (p<0.05). After miR-125b was exogenously overexpressed in A375 cells, the proliferation and migration ability of A375 cells was decreased, whereas the proportion of apoptotic cells rose (p<0.05). Besides, the results of dual-luciferase reporter assay revealed that the luciferase activity of A375 cells in the 3'-UTR of wild-type NCAM mRNA was overtly lowered compared with that of mutant NCAM mRNA (p<0.05).

Conclusions: MiR-125b acts as a tumor suppressor in MM cells by targeting and binding to NCAM.
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March 2021

Optical polarization-based seismic and water wave sensing on transoceanic cables.

Science 2021 02;371(6532):931-936

Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.

Seafloor geophysical instrumentation is challenging to deploy and maintain but critical for studying submarine earthquakes and Earth's interior. Emerging fiber-optic sensing technologies that can leverage submarine telecommunication cables present an opportunity to fill the data gap. We successfully sensed seismic and water waves over a 10,000-kilometer-long submarine cable connecting Los Angeles, California, and Valparaiso, Chile, by monitoring the polarization of regular optical telecommunication channels. We detected multiple moderate-to-large earthquakes along the cable in the 10-millihertz to 5-hertz band. We also recorded pressure signals from ocean swells in the primary microseism band, implying the potential for tsunami sensing. Our method, because it does not require specialized equipment, laser sources, or dedicated fibers, is highly scalable for converting global submarine cables into continuous real-time earthquake and tsunami observatories.
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http://dx.doi.org/10.1126/science.abe6648DOI Listing
February 2021

Bifunctional Carbon Dots Derived From an Anaerobic Bacterium of Porphyromonas gingivalis for Selective Detection of Fe and Bioimaging.

Photochem Photobiol 2021 May 21;97(3):574-581. Epub 2020 Dec 21.

College of Materials Science and Engineering, Liaocheng University, Liaocheng, China.

In this study, for the first time, Porphyromonas gingivalis, an anaerobic bacterium, was selected to synthesize carbon dots. The achieved P. gingivalis-carbon dots (Pg-CDs) exhibited strong fluorescence and high stability with capability for dual function as Fe sensor and intracellular imaging agent. The detection limit for Fe was as low as 1.85 µm. On the other hand, the prepared Pg-CDs were an excellent candidate for biosensor with high biocompatibility.
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http://dx.doi.org/10.1111/php.13360DOI Listing
May 2021

In vitro preparation of uniform and nucleic acid free hepatitis B core particles through an optimized disassembly-purification-reassembly process.

Protein Expr Purif 2021 02 6;178:105747. Epub 2020 Sep 6.

National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China. Electronic address:

Structure heterogeneity and host nucleic acids contamination are two major problems for virus-like particles (VLPs) produced by various host cells. In this study, an in vitro optimized disassembly-purification-reassembly process was developed to obtain uniform and nucleic acid free hepatitis B core (HBc) based VLPs from E. coli fermentation. The process started with ammonium sulfate precipitation of all heterogeneous HBc structures after cell disintegration. Then, dissolution and disassembly of pellets into basic subunits were carried out under the optimized disassembly condition. All contaminants, including host nucleic acids and proteins, were efficiently removed with affinity chromatography. The purified subunits reassembled into VLPs by final removal of the chaotropic agent. Two uniform and nucleic acid free HBc-based VLPs, truncated HBc and chimeric HBc-MAGE3 I, were successfully prepared. It was found that disassembly degree of HBc-based VLPs had a great influence on the protein yield, nucleic acid removal and reassembly efficiency. 4 M urea was optimal because lower concentration would not disassemble the particles completely while higher concentration would further denature the subunits into disordered aggregate and could not be purified and reassembled efficiently. For removal of strong binding nucleic acids such as in the case of HBc-MAGE3 I, benzonase nuclease was added to the disassembly buffer before affinity purification. Through the optimized downstream process, uniform and nucleic acid free HBc VLPs and HBc-MAGE3 I VLPs were obtained with purities above 90% and yields of 55.2 and 43.0 mg/L, respectively. This study would be a reference for efficient preparation of other VLPs.
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http://dx.doi.org/10.1016/j.pep.2020.105747DOI Listing
February 2021

Bcl-2 Proteins Regulate Mitophagy in Lipopolysaccharide-Induced Acute Lung Injury via PINK1/Parkin Signaling Pathway.

Oxid Med Cell Longev 2020 20;2020:6579696. Epub 2020 Feb 20.

Department of Anesthesiology, Shenzhen Hospital, Southern Medical University, No. 1333, Xinhu Road, Baoan District, Shenzhen, Guangdong Province, 518110, China.

Mitophagy is involved in sepsis-induced acute lung injury (ALI). Bcl-2 family proteins play an important role in mitochondrial homeostasis. However, whether targeting Bcl-2 proteins (Bcl-2 and Bad) could influence mitophagy in ALI remains unclear. In this study, lipopolysaccharide (LPS) was used to induce injury in A549 cells and ALI in mice. LPS treatment resulted in elevated cell apoptosis, enhanced mitophagy, decreased Bcl-2 expression, increased Bad expression, and activation of PINK1/Parkin signaling in cells and lung tissues. Both Bcl-2 overexpression and Bad knockdown attenuated LPS-induced injury, inhibited cell apoptosis and mitophagy, and improved survival. Atg5 knockout (KO) inhibited LPS-induced cell apoptosis. Furthermore, Bcl-2 proteins regulated mitophagy by modulating the recruitment of Parkin from the cytoplasm to mitochondria via direct protein-protein interactions. These results were further confirmed in Park2 KO cells and Park2 mice. This is the first study to demonstrate that Bcl-2 proteins regulated mitophagy in LPS-induced ALI via modulating the PINK1/Parkin signaling pathway, promoting new insights into the mechanisms and investigation of therapeutic strategies for a septic patient with ALI.
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http://dx.doi.org/10.1155/2020/6579696DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7054785PMC
October 2020

Quantitative assessment of condyle positional changes before and after orthognathic surgery based on fused 3D images from cone beam computed tomography.

Clin Oral Investig 2020 Aug 15;24(8):2663-2672. Epub 2019 Nov 15.

Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, China.

Objectives: To establish one method that can be used to quantitatively evaluate the condyle positional changes with 3D images in postoperative mandibular prognathism patients.

Materials And Methods: This is a retrospective observational study. Twenty-one patients who underwent bilateral sagittal split ramus osteotomy (BSSRO) were scanned with cone beam computed tomography (CBCT) for temporomandibular joints (TMJs) at 1 week preoperatively (T), 1 to 2 weeks (T), 3 months (T), 6 months (T), and 12 months (T) postoperatively. The data were then grouped into TT, TT, TT, TT and TT, TT, TT, and TT. Semi-automatic registration was conducted, and the condyle positional changes were measured in segmented 3D models. Inter- and intra-observer variability and the repeatability of registration were analyzed with paired t test; the repeated measurement analysis of variance was used for analyzing the repeatability of the marked points; the consistency of segmentation was analyzed with nonparametric test of multiple paired samples (Friedman test) and the independent-sample t test was applied to comparing changes between different periods of time. Differences were considered to be statistically significant when P < 0.05.

Results: In TT and TT, the condylar position was changed greatly. In TT, the mean condylar translations were less than 0.2 mm in all directions, the mean rotational changes of condyle were less than 0.2 mm; in the period of TT, the mean condylar translations in all directions were less than 0.02 mm. For series 2, the condyle translational changes in axial, coronal, and sagittal views were within 0.10 mm, and the rotation direction of condyle in all three views was the same within 1 year after operation.

Conclusions: Fused three-dimensional images can be used to qualitatively and quantitatively evaluate condyle positional changes. The condylar position might be stable at 3 months postoperatively. The condyles of most of patients did not fully return to their preoperative position within 1 year after the operation.

Clinical Relevance: One method for fusing images has been established to detect the condylar positional changes. This method may be applied to estimate the bony changes of condyle, even bony changes in other part of dentomaxillofacial region. Meanwhile, the data of condyle positional changes from asymptomatic patients after the surgery within 1 year can be used as a reference for further exploration of the relationship between orthognathic surgery and the occurrence of osteoarthritis postoperatively in the future.

Key Points: • By fused 3D images, the change of condylar position after bilateral sagittal split ramus osteotomy can be observed intuitively. • For the patients with mandibular prognathism, the condylar position would be stable at 3 months postoperatively. • The condyles of most mandibular prognathism patients did not fully return to their preoperative position within 1 year after operation.
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http://dx.doi.org/10.1007/s00784-019-03128-zDOI Listing
August 2020

Efficacy and Tolerability of Sufentanil, Dexmedetomidine, or Ketamine Added to Propofol-based Sedation for Gastrointestinal Endoscopy in Elderly Patients: A Prospective, Randomized, Controlled Trial.

Clin Ther 2019 09 23;41(9):1864-1877.e0. Epub 2019 Jul 23.

Department of Anesthesiology, Shenzhen Hospital, Southern Medical University, Shenzhen, Guangdong, China. Electronic address:

Purpose: To investigate the optimal agent combined with propofol for sedation in elderly patients undergoing gastrointestinal endoscopy.

Methods: A total of 120 elderly patients scheduled for gastrointestinal endoscopy under propofol-based sedation were randomly allocated to receive propofol + saline (control group), propofol + sufentanil 0.1 μg/kg, propofol + dexmedetomidine 0.4 μg/kg, or propofol + ketamine 0.4 mg/kg. Mean arterial pressure, heart rate, pulse oximetry, pressure of end-tidal carbon dioxide, respiratory rate, and Ramsay sedation scale score were recorded. Induction time, procedure time, recovery time, propofol dose, and adverse events were also recorded.

Findings: During the sedation procedure, the AUC of HR was lowest in the propofol + dexmedetomidine group (all, P < 0.05), and the AUC of pulse oximetry was significantly higher in the propofol + dexmedetomidine and propofol + ketamine groups compared to the other 2 groups (both, P < 0.05). The propofol + dexmedetomidine group had the highest prevalences of hypotension and bradycardia, and the control group experienced the largest number of hypoxia episodes (all, P < 0.05). The control group consumed the highest dose of propofol, while the propofol + ketamine group needed the lowest dose (all, P < 0.05).

Implications: The combination of propofol + ketamine 0.4 mg/kg maintained hemodynamic and respiratory stability, as evidenced by less hypotension, bradycardia, and hypoxia events, in elderly patients undergoing gastrointestinal endoscopy. China clinical trial registration (chictr.org.cn) ID: ChiCTR-INR-17013710.
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http://dx.doi.org/10.1016/j.clinthera.2019.06.011DOI Listing
September 2019

Self-sacrificial label assisted electroactivity conversion of sensing interface for ultrasensitive electrochemical immunosensor.

Biosens Bioelectron 2019 Sep 30;140:111355. Epub 2019 May 30.

Department of Chemistry, Capital Normal University, Beijing, 100048, China. Electronic address:

Sensitivity amplification strategies in electrochemical immunoassays are mainly limited by redox signal leaking, degradation of catalytic activity caused by layers of decoration and the large hindrance effect caused by immunoprobes. Herein, we developed an innovative sensitivity amplification strategy based on the self-sacrificial label-assisted electroactivity conversion of a sensing interface, utilizing Fe-loaded polydopamine (Fe-PDA) nanoparticles as the self-sacrificial labels, which can be decomposed under acidic conditions and release Fe. When the assembled sensing interface was immersed in a prussian blue (PB) precursor solution (a mixed solution of 0.1 M KCl, 0.1M HCl and 1 mM KFe(CN)), the as-formed sandwich-type structure was destroyed due to the decomposition of Fe-PDA caused by HCl in PB precursor solution, resulting in the reduce of interface resistance. The released Fe reacted with the PB precursor solution and triggered the growth of electroactive PB nanoparticles (PB NPs) on the sensing interface. Assisted by self-sacrificial Fe-PDA, the sensing interface was converted from electrochemically inactive to electroactive with a strong redox signal, high catalytic activity, and decreased interface resistance. The PB NPs can catalyse HO to amplify the redox signal, thus improving sensitivity. The redox signal and catalysts were generated in the final assembly step, which can avoid signal leaking and decreases of catalytic activity caused by layers of decoration. The decomposition of Fe-PDA can eliminate the large hindrance effect of the immunoprobe. Ultrasensitive quantification of carbohydrate antigen 125 (CA 125) was realized with a detection range from 0.00001 to 1000 U mL and detection limit of 0.25 × 10 U mL.
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http://dx.doi.org/10.1016/j.bios.2019.111355DOI Listing
September 2019

Effect of fracture orientation on detection accuracy of vertical root fractures in non-endodontically treated teeth using cone beam computed tomography.

Clin Oral Investig 2019 Dec 13;23(12):4433-4439. Epub 2019 Apr 13.

Oral and Maxillofacial Radiology, Applied Oral Sciences, Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, Sai Ying Pun, Hong Kong, SAR, China.

Objectives: This study aimed to investigate the effect of fracture orientation on the detection accuracy of vertical root fractures (VRFs) in non-endodontically treated teeth using four different cone beam computed tomography (CBCT) units.

Materials And Methods: Thirty eight out of 148 extracted human permanent teeth were chosen randomly, and VRFs were artificially induced to result in 20 mesiodistally and 18 buccolingually oriented root fractures. The fracture width was subsequently measured. All the teeth were scanned with four CBCT units. CBCT images were evaluated independently by two observers. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated for each observer and fracture orientation. The AUC between the two fracture orientations was compared using Z test.

Results: The mean fracture width was 140 μm (standard deviation 26.8 μm). A statistically significant difference was found between the mesiodistal and buccolingual VRFs for the AUC from the CBCT unit 3D Accuitomo 170 (p = 0.02). There were no statistically significant differences between the mesiodistal and buccolingual VRFs for AUCs from the CBCT units NewTom VGi (p = 0.21), ProMax 3D Mid (p = 0.23), and i-CAT FLX (p = 0.21).

Conclusion: Fracture orientations of teeth with VRFs in non-endodontically treated teeth may play a role in the detection accuracy of CBCT images, but this effect seems to be dependent on the CBCT unit used.

Clinical Relevance: Although for most of the CBCT units tested, the fracture orientation of VRF in non-endodontically treated teeth seems not to play a role for the diagnosis, clinical data is needed to further assess the impact of different devices on VRF detection.
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http://dx.doi.org/10.1007/s00784-019-02905-0DOI Listing
December 2019

Ca-Triggered pH-Response Sodium Alginate Hydrogel Precipitation for Amplified Sandwich-Type Impedimetric Immunosensor of Tumor Marker.

ACS Sens 2019 02 24;4(2):450-455. Epub 2019 Jan 24.

Department of Chemistry , Capital Normal University , Beijing 100048 , China.

Signal amplification is of great significance in the ultrasensitive electrochemical impedimetric immunoassays for tumor marker detection. A cascaded signal amplification approach was designed using gold nanoparticle-CaCO microspheres (AuNP-CaCO) to trigger pH-responsive alginate hydrogel precipitation for sandwich-type impedimetric immunosensor. AuNP-CaCO exerts a large hindrance effect and can release Ca ions under weak acidic conditions, and thus can serve as a multifunctional label. The hindrance effect of AuNP-CaCO can significantly enhance the impedance response as the initial signal amplification. Then, part of CaCO dissolves under weak acid conditions and releases Ca, which can cross-link with alginate to generate an insoluble alginate hydrogel precipitate on the sensing interface, significantly increasing the impedance signal. The impedance signal can be further amplified by making the hydrogel negatively charged based on the pH-responsive surface charge properties of the alginate hydrogel. Benefiting from the cascaded signal amplification, this impedimetric immunosensor exhibits a linear range from 1.0 fg mL to 100 ng mL, an detection limit of 0.09 fg mL, and ultrahigh sensitivity of 973.01 Ω (lg(ng mL)) toward the assay of prostate specific antigen (PSA).
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http://dx.doi.org/10.1021/acssensors.8b01465DOI Listing
February 2019

Degradation kinetics and mechanism of 3-Chlorobenzoic acid in anoxic water environment using graphene/TiO as photocatalyst.

Environ Technol 2020 Jul 20;41(17):2165-2179. Epub 2018 Dec 20.

School of Resources Environment and Chemical Engineering, Nanchang University, Nanchang, People's Republic of China.

Degradation kinetics and mechanism of 3-Chlorobenzoic acid (3-CBA) in anoxic water environment using graphene/TiO (GR/TiO) as photocatalyst had been investigated. The effects of various parameters such as catalyst dosage, pH, initial concentration, catalyst reuse and dissolved oxygen (DO) on 3-CBA photocatalytic degradation kinetics were studied. The qualitative and quantitative analysis for degradation intermediate products and parent compound were studied by using HPLC, HPLC/MS/MS and IC technologies. The results show that the residual concentration of 3-CBA has a good linear relationship and its correlation coefficient are all greater than 0.985 by Langmuir-Hinshelwood (L-H) dynamic model under different photocatalytic degradation conditions. Some oxidative degradation products such as 3-chlorophenol, resorcinol, and hydroxyquinol are generated, and some reductive degradation products such as 3-chlorobenzaldehyde, 3-hydroxybenzaldehyde, 3-hydroxybenzyl alcohol, and cyclohexanediol are produced, and part of 3-CBA are mineralized to generate CO when DO is in the range of 0.5-1.0 mg/L; When DO is less than 0.28 mg/L, photocatalytic reduction mainly occurs. The results provide a theoretical basis for photocatalytic remediation of pollutants in anoxic water environment.
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http://dx.doi.org/10.1080/09593330.2018.1556741DOI Listing
July 2020

Laser cooling of thallium chloride: A theoretical investigation.

J Chem Phys 2018 Sep;149(9):094306

Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China.

The possibility of laser cooling of thallium chloride (TlCl) molecules has been investigated based on high-level calculations with the consideration of the core-valence and the spin-orbit coupling (SOC) effects. The potential energy curves of the 13 Λ-S states as well as the 24 Ω states split from them via SOC are obtained by multi-reference configuration interaction plus the Davidson correction. We show that the a transition of TlCl is a possible candidate for laser cooling, which features highly diagonal Franck-Condon factors and no intermediate interacting electronic states. Based on our calculations, we propose an optical cycling scheme by utilizing four lasers at wavelengths around 320 nm with more than 10 cycles for photon absorption/emission and a sub-microkelvin temperature limit.
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http://dx.doi.org/10.1063/1.5044387DOI Listing
September 2018

Electrochemical immunoassay for tumor markers based on hydrogels.

Expert Rev Mol Diagn 2018 05 8;18(5):457-465. Epub 2018 May 8.

a Department of Chemistry , Capital Normal University , Beijing , China.

Introduction: Hydrogel-based electrochemical immunoassays exhibit a large surface-to-volume ratio, excellent biocompatibility, unique stimuli-responsive behavior, high permeability and hydrophilicity and, thus, have shown great potential in the sensitive and accurate detection of tumor markers. Electrochemical immunosensing techniques for tumor markers based on hydrogels have greatly progressed in recent years. Areas covered: In this review, the authors describe the recent advances of hydrogel-based electrochemical immunosensing interface of tumor markers based on the different functions of hydrogels including conductive, catalytic, redox, stimuli-responsive and antifouling hydrogels. Expert commentary: Hydrogels have been successfully employed in electrochemical immunoassay of tumor markers, which is accountable to their unique properties. For further exploitation of hydrogel-based electrochemical biosensors, more variety of hydrogels need be fabricated with improved functionality.
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http://dx.doi.org/10.1080/14737159.2018.1472579DOI Listing
May 2018

Extending Half Life of H-Ferritin Nanoparticle by Fusing Albumin Binding Domain for Doxorubicin Encapsulation.

Biomacromolecules 2018 03 5;19(3):773-781. Epub 2018 Feb 5.

State Key Laboratory of Biochemical Engineering, Institute of Process Engineering , Chinese Academy of Sciences , Beijing 100190 , China.

Nanoparticles based on the heavy chain of the human ferritin (HFn) are arousing growing interest in the field of drug delivery due to their exceptional characteristics. However, the unsatisfied plasma half life of HFn substantially limits its application as a delivery platform for antitumor agents. Herein we fused an albumin binding domain (ABD) variant that basically derives from the streptococcal protein G and possesses a long-acting characteristic in serum albumin to the N-terminus of the HFn for the aim of half-life extension. This ABD-HFn construct was highly expressed and fully self-assembled into symmetrical and spherical structure in E. coli bacteria. The purified ABD-HFn showed a similar particle size with wild-type HFn and also exhibited an extremely high binding affinity with human serum albumin. To evaluate the therapeutic potential of this ABD-HFn construct in terms of half-life extension, we encapsulated a model antitumor agent doxorubicin (DOX) into the ABD-HFn. Significantly outstanding loading efficacy of above 60 molecules doxorubicin for each ABD-HFn cage was achieved. The doxorubicin-loaded ABD-HFn nanoparticle was characterized and further compared with the recombinant HFn counterpart. The ABD-HFn/DOX nanoparticle showed dramatically improved stability and comparable cell uptake rate when compared with HFn/DOX counterpart. Pharmacokinetics study in Sprague-Dawley rats showed that ABD-HFn/DOX nanoparticle possessed significantly prolonged plasma half life of ∼17.2 h, exhibiting nearly 19 times longer than that of free doxorubicin and 12 times for HFn/DOX. These optimal results indicated that fusion with ABD will be a promising strategy to extend the half life for protein-based nanoparticles.
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http://dx.doi.org/10.1021/acs.biomac.7b01545DOI Listing
March 2018

Label-free electrochemical immunosensor for ultrasensitive detection of neuron-specific enolase based on enzyme-free catalytic amplification.

Anal Bioanal Chem 2018 Feb 15;410(4):1279-1286. Epub 2017 Dec 15.

Department of Chemistry, Capital Normal University, Beijing, 100048, China.

Enzyme-free catalytic amplification is of great significance for sensitive label-free electrochemical immunosensors. In this study, an enzyme-free catalytic amplification based label-free amperometric immunosensor was developed for sensitive detection of neuron-specific enolase (NSE) by use of a AuPd nanoparticle-multiwalled carbon nanotube (AuPd-MWCNT) composite, ferrocenecarboxaldehyde (Fc-CHO), and chitosan hybrid hydrogel. The intrinsic virtues of chitosan not only resulted in bioactivity of the attached antibodies and made the other component of the immunosensor easier to fix on the electrode, but also imparted abundant binding sites to the hydrogel to condense Fc-CHO to achieve the initial signal amplification. Fc-CHO, which served as an electroactive species to generate a redox response, also exhibits excellent electrocatalytic activity toward HO. AuPd-MWCNT composite, with enhanced peroxidase-like catalytic activity, could catalyze HO to accelerate electron transfer. When HO was present in the detection solution, synergetic catalysis of Fc-CHO and AuPd-MWCNT composite toward HO was achieved, thus realizing enzyme-free signal amplification. On the basis of this enzyme-free signal amplification, the electrochemical immunosensing platform provided a wide linear range from 1 pg mL to 100 ng mL, a low detection limit of 0.483 pg mL, and high sensitivity of 7.22 μA (log C ). Moreover, the immunosensor showed enormous potential in clinical application. Graphical abstract An enzyme-free catalytic amplification based label-free amperometric immunosensor was developed for sensitive detection of neuron-specific enolase (NSE) by use of a AuPd nanoparticle-multiwalled carbon nanotube (MWCNT) composite, ferrocenecarboxaldehyde (Fc-CHO), and chitosan (CS) hybrid hydrogel. BSA bovine serum albumin, GA glutaraldehyde, SWV square wave voltammetry.
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http://dx.doi.org/10.1007/s00216-017-0767-yDOI Listing
February 2018

Albumin Binding Domain Fusing R/K-X-X-R/K Sequence for Enhancing Tumor Delivery of Doxorubicin.

Mol Pharm 2017 11 9;14(11):3739-3749. Epub 2017 Oct 9.

State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences , Beijing 100190, China.

For the purpose of improving the tumor delivery of doxorubicin (DOX), a kind of peptide-DOXO conjugate was designed and prepared, in which the peptide composed of an albumin-binding domain (ABD) and a tumor-specific internalizing sequence (RGDK or RPARPAR) was conjugated to a (6-maleimidocaproyl) hydrazone derivative of doxorubicin (DOXO-EMCH). The doxorubicin uptake by lung cancer cell line of A549 evidenced that the conjugates are capable of being internalized through a tumor-specific sequence mediated manner, and the intracellular imaging of distribution in A549 cell demonstrated that the conjugated doxorubicin can be delivered to the cell nucleus. The A549 cell cytotoxicity of peptide-DOXO conjugates was presented with IC values and shown in the range of about 9-11 μM. Pharmacokinetics study revealed that both conjugates exhibited nearly 5.5 times longer half-time than DOX, and about 4 times than DOXO-EMCH. The in vivo growth inhibitions of the two peptide-DOXO conjugates on BALB/c nude mice bearing A549 tumor (47.78% for ABD-RGDK-DOXO and 47.09% for ABD-RPARPAR-DOXO) were much stronger than that of doxorubicin and DOXO-EMCH (24.28% and 25.67% respectively) at a doxorubicin equivalent dose. Besides, the in vivo fluorescence imaging study confirmed that the peptide markedly increased the payload accumulation in tumor tissues and indicated that albumin binding domain fusing tumor-specific sequence effectively enhanced the tumor delivery of doxorubicin and thus improved its therapeutic potency.
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http://dx.doi.org/10.1021/acs.molpharmaceut.7b00497DOI Listing
November 2017

Exploring the structure and photodissociation mechanism of the electronic states of iodocarbene, CHI: a theoretical contribution.

Phys Chem Chem Phys 2017 Jul 28;19(27):17735-17744. Epub 2017 Jun 28.

Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China. and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012, China.

We present herein a high-level ab initio study on the mono-iodine substituted carbene, CHI, using internally contracted multireference configuration interaction (icMRCI-F12) with Davidson correction which employs wave functions that explicitly depend on the electron-electron distance. The spin-orbit coupling (SOC) effect was included in our calculations. A total of 20 spin-free states with vertical transition energy up to 7.4 eV, as well as 50 spin-coupled states generated from the spin-free states via the SOC were studied. The results show significant influence of the SOC on the bond angles and the harmonic vibrational frequencies of the bending mode of the ground state (XA') and the lowest triplet state (aA''). Potential energy curves along the bond angle and the bond lengths of the electronic excited states of CHI were investigated. Based on our calculations, photodissociation dynamics in the ultraviolet region was disscussed for the first time, which would pave the way to further experimental investigations of CHI.
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http://dx.doi.org/10.1039/c7cp02575kDOI Listing
July 2017

Two cadmium(II) fluorous coordination compounds tuned by different bipyridines.

Acta Crystallogr C Struct Chem 2017 May 26;73(Pt 5):424-429. Epub 2017 Apr 26.

Department of Chemistry and Chemical Engineering, Jining University, Xing Tan Road, Qufu, Shandong Province 273155, People's Republic of China.

Fluorine is the most electronegative element and can be used as an excellent hydrogen-bond acceptor. Fluorous coordination compounds exhibit several advantageous properties, such as enhanced high thermal and oxidative stability, low polarity, weak intermolecular interactions and a small surface tension compared to hydrocarbons. C-H...F-C interactions, although weak, play a significant role in regulating the arrangement of the organic molecules in the crystalline state and stabilizing the secondary structure. Two cadmium(II) fluorous coordination compounds formed from 2,2'-bipyridine, 4,4'-bipyridine and pentafluorobenzoate ligands, namely catena-poly[[aqua(2,2'-bipyridine-κN,N')(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-2,3,4,5,6-pentafluorobenzoato-κO:O'], [Cd(CFO)(CHN)(HO)], (1), and catena-poly[[diaquabis(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-4,4'-bipyridine-κN:N'], [Cd(CFO)(CHN)(HO)], (2), have been synthesized solvothermally and structurally characterized. Compound (1) shows a one-dimensional chain structure composed of Cd-O coordination bonds and is stabilized by π-π stacking and O-H...O hydrogen-bond interactions. Compound (2) displays a one-dimensional linear chain structure formed by Cd-N coordination interactions involving the 4,4'-bipyridine ligand. Adjacent one-dimensional chains are extended into two-dimensional sheets by O-H...O hydrogen bonds between the coordinated water molecules and adjacent carboxylate groups. Moreover, the chains are further linked by C-H...F-C interactions to afford a three-dimensional network. In both structures, hydrogen bonding involving the coordinated water molecules is a primary driving force in the formation of the supramolecular structures.
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http://dx.doi.org/10.1107/S2053229617006003DOI Listing
May 2017

A Rare Case of Two Accessory Maxillae 
with Bilateral Tessier 7 clefts.

Chin J Dent Res 2017;20(1):53-58

A 10-year-old Chinese girl with two accessory maxillae and bilateral Tessier no. 7 clefts is presented. Radiographic examination showed two accessory maxillae, each containing 5 or 6 supernumerary permanent teeth. The two accessory maxillae extended from the inside of the zygomatic arch to the maxillary tuberosity symmetrically. Duplication of the maxilla is always associated with Amniotic Band Syndrome (ABS), but this case may be a distinct syndrome representing an under-recognised phenotype with bilateral maxillae duplication and Tessier no. 7 clefts.
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http://dx.doi.org/10.3290/j.cjdr.a37742DOI Listing
July 2017

The detection accuracy of cone beam CT for osseous defects of the temporomandibular joint: a systematic review and meta-analysis.

Sci Rep 2016 10 6;6:34714. Epub 2016 Oct 6.

Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.

The purpose of this review was to evaluate whether cone-beam computed tomography (CBCT) is reliable for the detection of bone changes of the temporomandibular joint (TMJ). Studies collected from the PubMed, Web of Science, Cochrane Library, ScienceDirect, Embase, Wanfang and CNKI databases were searched, and the publishing time was limited from January 1990 to December 2015. Eight studies (23 experimental research groups) were eventually included for further analysis. The pooled sensitivity was 0.67 and the pooled specificity was 0.87, which leads to a relatively large area (0.84) under the Receiver Operating Characteristic (ROC) curve. The related pooled positive likelihood ratio (+LR) and the pooled negative likelihood ratio (-LR) were 5.2 and 0.38, respectively. The subgroup analysis was conducted for four subgroups categorized by voxel size (≤0.2; >0.2, ≤0.3; >0.3, ≤0.4; >0.4, and ≤0.5 (mm)), and the ">0.4, ≤0.5" subgroup had a higher pooled sensitivity and pooled specificity than the other groups. The present study demonstrates that CBCT has a relatively high diagnostic accuracy for TMJ bone changes, although its reliability is limited. Voxel size did not play a role in the accuracy of CBCT.
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http://dx.doi.org/10.1038/srep34714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052594PMC
October 2016

[Effects of autophagy on lipopolysaccharide-induced vascular hyper-permeability].

Zhonghua Wei Zhong Bing Ji Jiu Yi Xue 2016 Aug;28(8):673-7

Department of Critical Care Medicine, the First People's Hospital of Chenzhou, Chenzhou 423000, Hunan, China (Wang SB, Li YF, Li T); The Graduate School of Guangdong Medical University, Zhanjiang 524000, Guangdong, China (Yin S); Department of Anesthesiology, Shenzhen Hospital, Southern Medical University, Shenzhen 518000, Guangdong, China (Yin S, Li CL, Liu YT). Corresponding author: Liu Youtan, Email:

Objective: To investigate the effects of autophagy on lipopolysaccharide (LPS)-induced vascular hyper-permeability.

Methods: (1) In vitro: Human umbilical vein endothelial cells (HUVECs) were randomly divided into blank group, LPS group (5 mg/L LPS stimulation), autophagy inhibitor 6-amino-3-methyl purine (3-MA) + LPS group (5 mmol/L 3-MA pretreatment for 30 minutes + 5 mg/L LPS stimulation) and autophagy revulsive Rapamycin (RAP) + LPS group (10 nmol/L RAP pretreatment for 30 minutes + 5 mg/L LPS stimulation). After LPS simulation for 60 minutes in four groups, endothelial permeability was detected by trans-endothelial electrical resistance (TER) determination. The protein expressions of autophagy marker protein microtubule-associated protein 1 light chain 3 (LC3 II/I) and autophagy related gene Beclin-1 were detected by Western Blot. Cell apoptosis was evaluated by using flow cytometry. Caspase-3 activity was detected by fluorometric assay kit. (2) In vivo: 24 Sprague-Dawley (SD) rats were randomly assigned to four groups according to random number table, with 6 rats in each group. The rats in control group received no treatment; rats in model group were tail intravenous injected 10 mg/kg of LPS. The rats in 3-MA pretreatment and RAP pretreatment groups were tail intravenous injected 10 mg/kg of 3-MA or 2 mg/kg of RAP pretreatment for 30 minutes before 10 mg/kg LPS injection. The extravasation of FITC-albumin in mesenteric post-capillary venules was observed by fluorescence microscope. Then the change in fluorescence intensity of FITC-albumin between the intravascular and extravascular space (ΔI) were measured to reflect vascular permeability.

Results: (1) In vitro, compared with blank group, the LC3 II/I protein, Beclin-1 protein, caspase-3 activity and rate of cell apoptosis in LPS group were increased, and the TER was decreased. Compared with LPS group, the LC3 II/I, Beclin-1, caspase-3 activity and rate of cell apoptosis in 3-MA+LPS group were decreased, and the TER was increased [LC3 II/I protein: (288.2±33.3)% vs. (420.5±39.4)%, Beclin-1 protein: (185.3±26.4)% vs. (293.3±36.1)%, caspase-3 activity: (196.6±28.5)% vs. (339.5±25.4)%, rate of cell apoptosis: (9.50±0.99)% vs. (15.40±1.55)%, TER: 0.88±0.09 vs. 0.63±0.05, all P < 0.05]. Compared with LPS group, the LC3 II/I, Beclin-1, caspase-3 activity and rate of cell apoptosis in RAP+LPS group were further increased, and the TER was further decreased [LC3 II/I protein: (519.6±45.2)% vs. (420.5±39.4)%, Beclin-1 protein: (359.0±38.3)% vs. (293.3±36.1)%, caspase-3 activity: (449.1±31.0)% vs. (339.5±25.4)%, rate of cell apoptosis: (19.30±1.72)% vs. (15.40±1.55)%, TER: 0.54±0.05 vs. 0.63±0.05, all P < 0.05]. (2) In vivo, the albumin extravasation and vascular permeability were increased in model group as compared with those of control group (ΔI: 0.54±0.07 vs. 0.13±0.03, P < 0.05). The albumin extravasation and vascular permeability were obviously decreased in 3-MA pretreatment group as compared with those of model group (ΔI: 0.25±0.05 vs. 0.54±0.07, P < 0.05). The albumin extravasation and vascular permeability were obviously increased in RAP pretreatment group as compared with those of model group (ΔI: 0.67±0.07 vs. 0.54±0.07, P < 0.05).

Conclusions: Inhibition of autophagy can reduce the LPS-induced vascular hyper-permeability, and enhanced autophagy can further increase vascular permeability. The mechanism of autophagy mediate vascular permeability may be related to the endothelial cells apoptosis.
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http://dx.doi.org/10.3760/cma.j.issn.2095-4352.2016.08.001DOI Listing
August 2016

Toxic effect of NiCl2 on development of the bursa of Fabricius in broiler chickens.

Oncotarget 2016 Jan;7(1):125-39

Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Ya'an, Sichuan, China.

This study was conducted with objective of evaluating the toxic effects of nickel chloride (NiCl2) on development of bursa of Fabricius in broilers fed on diets supplemented with 0, 300, 600 and 900 mg/kg of NiCl2 for 42 days by using the methods of experimental pathology, flow cytometry (FCM), and quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that dietary NiCl2 in 300 mg/kg and over induced toxic suppression in the bursal development, which was characterized by decreasing lymphocytes histopathologically and relative weight, increasing G0/G1 phase (a prolonged nondividing state), reducing S phase (DNA replication) and proliferating index, and increasing percentages of apoptotic cells. Concurrently, the mRNA expression levels of bax, cytochrome c (cyt c), apoptotic peptidase activating factor 1 (Apaf-1), caspase-3, caspase-6, caspase-7 and caspase-9 were increased and the bcl-2 mRNA expression levels were decreased. The toxic suppression of bursal development finally impaired humoral immunity duo to the reduction of B lymphocyte population and B lymphocyte activity in the broiler chicken. This study provides new evidences for further studying the effect mechanism of Ni and Ni compoundson B-cell or bursa of Fabricius.
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http://dx.doi.org/10.18632/oncotarget.6591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807987PMC
January 2016

Nickel Chloride (NiCl2) Induces Histopathological Lesions via Oxidative Damage in the Broiler's Bursa of Fabricius.

Biol Trace Elem Res 2016 May 6;171(1):214-23. Epub 2015 Oct 6.

Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Ya'an, China.

The purpose of this study was to investigate the histopathological lesions, oxidative damage, changes of immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) contents in the bursa of Fabricius and serum immunoglobulins (IgG, IgM, IgA) induced by dietary nickel chloride (NiCl2). Two hundred and eighty-one-day-old broilers were randomly divided into four groups and fed on a control diet and three experimental diets supplemented with 300, 600, and 900 mg/kg of NiCl2 for 42 days. Lesions were observed in the NiCl2-treated groups. Histopathologically, lymphocytes were decreased in lymphoid follicles with thinner cortices and wider medullae. Concurrently, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the ability to inhibit hydroxyl radical and glutathione (GSH) contents were significantly (p < 0.05 or p < 0.01) decreased, while malondialdehyde (MDA) contents were increased in the NiCl2-treated groups. The serum IgG, IgM, and bursa IgG and IgM contents were significantly (p < 0.05 or p < 0.01) lower in the NiCl2-treated groups than those in the control group. The above-mentioned results show that dietary NiCl2 in excess of 300 mg/kg can cause histopathological lesions via oxidative damage, which finally impairs the function of the bursa of Fabricius and reduces IgG and IgM contents of the serum and the bursa of Fabricius. The study is aimed to provide helpful materials for studies on Ni- or Ni compounds-induced B cell toxicity in both human and other animals in the future.
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http://dx.doi.org/10.1007/s12011-015-0528-8DOI Listing
May 2016

Escherichia coli O157:H7 strains harbor at least three distinct sequence types of Shiga toxin 2a-converting phages.

BMC Genomics 2015 Sep 29;16:733. Epub 2015 Sep 29.

Department of Food Science, The Pennsylvania State University, University Park, PA, 16802, USA.

Background: Shiga toxin-producing Escherichia coli O157:H7 is a foodborne pathogen that causes severe human diseases including hemolytic uremic syndrome (HUS). The virulence factor that mediates HUS, Shiga toxin (Stx), is encoded within the genome of a lambdoid prophage. Although draft sequences are publicly available for a large number of E. coli O157:H7 strains, the high sequence similarity of stx-converting bacteriophages with other lambdoid prophages poses challenges to accurately assess the organization and plasticity among stx-converting phages due to assembly difficulties.

Methods: To further explore genome plasticity of stx-converting prophages, we enriched phage DNA from 45 ciprofloxacin-induced cultures for subsequent 454 pyrosequencing to facilitate assembly of the complete phage genomes. In total, 22 stx2a-converting phage genomes were closed.

Results: Comparison of the genomes distinguished nine distinct phage sequence types (PSTs) delineated by variation in obtained sequences, such as single nucleotide polymorphisms (SNPs) and insertion sequence element prevalence and location. These nine PSTs formed three distinct clusters, designated as PST1, PST2 and PST3. The PST2 cluster, identified in two clade 8 strains, was related to stx2a-converting phages previously identified in non-O157 Shiga-toxin producing E. coli (STEC) strains associated with a high incidence of HUS. The PST1 cluster contained phages related to those from E. coli O157:H7 strain Sakai (lineage I, clade 1), and PST3 contained a single phage that was distinct from the rest but most related to the phage from E. coli O157:H7 strain EC4115 (lineage I/II, clade 8). Five strains carried identical stx2a-converting phages (PST1-1) integrated at the same chromosomal locus, but these strains produced different levels of Stx2.

Conclusion: The stx2a-converting phages of E. coli O157:H7 can be categorized into at least three phage types. Diversification within a phage type is mainly driven by IS629 and by a small number of SNPs. Polymorphisms between phage genomes may help explain differences in Stx2a production between strains, however our data indicates that genes encoded external to the phage affect toxin production as well.
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http://dx.doi.org/10.1186/s12864-015-1934-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4587872PMC
September 2015

Diversity of CRISPR loci and virulence genes in pathogenic Escherichia coli isolates from various sources.

Int J Food Microbiol 2015 Jul 27;204:41-6. Epub 2015 Mar 27.

Department of Food Science, The Pennsylvania State University, 202 Rodney A. Erickson Food Science Building, University Park, PA 16802, USA. Electronic address:

Shiga toxin-producing Escherichia coli (STEC) strains, including those of O157:H7 and the "big six" serogroups (i.e., O26, O45, O103, O111, O121, and O145) are food-borne pathogens that pose a serious health threat to humans. Ruminants, especially cattle, are a major reservoir for O157 and non-O157 STEC. In the present study, 115 E. coli strains isolated from small and very small beef processing plants were screened for virulence genes (stx1, stx2, eae) using a multiplex polymerase chain reaction (PCR). Thirteen (11.3%) of the 115 isolates tested positive for stx1, stx2, or eae genes, but only 4 (3.5%) tested positive for either stx1 or stx2. A multiplex PCR reaction targeting eight O-serogroups (O26, O45, O103, O111, O113, O121, O145, O157) identified 12 isolates as O26, O103, O111, or O145, with E. coli O26 being the most predominant serogroup (61.5%). The thirteen isolates were further analyzed using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) subtyping. Consistent with previous studies, CRISPR alleles from strains of the same serogroup were similar in their spacer content and order, regardless of the isolation source. A completely different CRISPR allele was observed in one isolate ("7-J") which exhibited a different O-serogroup (O78). Our results confirmed previous findings that CRISPR loci are conserved among phylogenetically-related strains. In addition, 8 E. coli O26 isolates and a collection of 42 E. coli O26 isolates were screened for 12 enterohemorrhagic E. coli-specific genes. Seven genes (ECs848-Hypothetical Protein, ECs2226-Hypothetical Protein, ECs3857-nleB, ECs3858-Hypothetical Protein, ECs4552-escF, ECs4553-Hypothetical Protein, and ECs4557-sepL) were found in all 50 isolates. An additional 5 genes (ECs1322-ureA urease subunit γ, ECs1323-ureB urease subunit β, ECs1326-ureF, ECs1561-Hypothetical Protein, and ECs1568-Hypothetical Protein) were found to be highly prevalent in isolates from human sources, while lower in isolates from beef processing plants, cattle, and other sources. This finding indicates the possible role of these genes in virulence of human O26 strains.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2015.03.025DOI Listing
July 2015

Inhibitive effects of nickel chloride (NiCl₂) on thymocytes.

Biol Trace Elem Res 2015 Apr 31;164(2):242-52. Epub 2014 Dec 31.

Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Sichuan Agricultural University, Ya'an, 625014, China.

The purpose of this study was to define the inhibitive effects of dietary nickel chloride (NiCl2) on thymocytes in broilers fed on diets supplemented with 0, 300, 600, and 900 mg/kg of NiCl2 for 42 days. We examined the changes of cell cycle phase, percentages of apoptotic cells, T cell subsets, cytokines, and mRNA expression of apoptotic proteins (bcl-2, bax, and caspase-3) in thymocytes by flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR). In the NiCl2-treated broilers, the percentages of thymocytes in G0/G1 phase were increased, whereas thymocytes in the S phase and the proliferation index were decreased. The percentages of apoptotic thymocytes were increased. Also, the mRNA expression levels of bax and caspase-3 were increased, and mRNA expression levels of bcl-2 were decreased. The percentages of CD3(+), CD3(+)CD4(+), and CD3(+)CD8(+) T lymphocytes in the thymus and peripheral blood were diminished. Concurrently, thymic cytokine (interleukin-1 beta (IL-1β), interleukin-2 (IL-2), interleukin-10 (IL-10), interleukin-12 p35 subunit (IL-12p35), interleukin-12 p40 subunit (IL-12p40), interleukin-21 (IL-21), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), thymosin β4, thymosin β10, and thymosin β15) mRNA expression levels were decreased. The abovementioned results showed that dietary NiCl2 in excess of 300 mg/kg inhibited thymocyte growth by arresting cell cycle, increasing apoptosis percentage, altering apoptotic protein mRNA expression levels, and downregulating cytokine expression levels.
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http://dx.doi.org/10.1007/s12011-014-0219-xDOI Listing
April 2015

NiCl2-down-regulated antioxidant enzyme mRNA expression causes oxidative damage in the broiler(')s kidney.

Biol Trace Elem Res 2014 Dec 25;162(1-3):288-95. Epub 2014 Sep 25.

Key Laboratory of Animal Diseases and Environmental Hazards of Sichuan Province, Yaan, China.

The kidney serves as a major organ of nickel (Ni) excretion and is a target organ for acute Ni toxicity due to Ni accumulation. There are no studies on the Ni or Ni compound-regulated antioxidant enzyme mRNA expression in animals and human beings at present. This study was conducted to investigate the pathway of nickel chloride (NiCl2)-caused renal oxidative damage by the methods of biochemistry, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay. Two hundred and eighty one-day-old broilers were randomly divided into four groups and fed on a control diet and three experimental diets supplemented with 300, 600, and 900 mg/kg of NiCl2 for 42 days. Dietary NiCl2 elevated the malondialdehyde (MDA), nitric oxide (NO), 8-hydroxy-2'-deoxyguanosine (8-OHdG) contents, and reduced the ability to inhibit hydroxy radical in the NiCl2-treated groups. Also, the renal inducible nitric oxide synthase (iNOS) activity and mRNA expression levels were increased. The total antioxidant (T-AOC) and activities of antioxidant enzymes including copper zinc superoxide dismutase (CuZn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and glutathione-s-transferase (GST) were decreased, and the glutathione (GSH) contents as well were decreased in the kidney. Concurrently, the renal CuZn-SOD, Mn-SOD, CAT, GSH-Px, GST, and GR mRNA expression levels were decreased. The above-mentioned results showed that dietary NiCl2 in excess of 300 mg/kg caused renal oxidative damage by reducing mRNA expression levels and activities of antioxidant enzymes, and then enhancing free radicals generation, lipid peroxidation, and DNA oxidation.
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http://dx.doi.org/10.1007/s12011-014-0132-3DOI Listing
December 2014