Publications by authors named "Ziyi Liu"

83 Publications

Weakly Supervised Temporal Action Localization through Contrast based Evaluation Networks.

IEEE Trans Pattern Anal Mach Intell 2021 May 11;PP. Epub 2021 May 11.

Given only video-level action categorical labels during training, weakly-supervised temporal action localization (WS-TAL) learns to detect action instances and locates their temporal boundaries in untrimmed videos. Compared to its fully supervised counterpart, WS-TAL is more cost-effective in data labeling and thus favorable in practical applications. However, the coarse video-level supervision inevitably incurs ambiguities in action localization, especially in untrimmed videos containing multiple action instances. To overcome this challenge, we observe that significant temporal contrasts among video snippets, i.e., caused by temporal discontinuities and sudden changes, often occur around true action boundaries. This motivates us to introduce a Contrast-based Localization EvaluAtioN Network (CleanNet), whose core is a new temporal action proposal evaluator, which provides fine-grained pseudo supervision by leveraging the temporal contrasts among snippet-level classification predictions. Moreover, the new action localization module is an integral part of CleanNet which enables end-to-end training. This is in contrast to many existing WS-TAL methods where action localization is merely a post-processing step. Besides, we also explore the usage of temporal contrast on temporal action proposal generation task, which we believe is the first attempt with the weak supervision setting. Experiments on the THUMOS14, ActivityNet v1.2 and v1.3 datasets validate the efficacy of our method.
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http://dx.doi.org/10.1109/TPAMI.2021.3078798DOI Listing
May 2021

Coupling SnS and rGO aerogel to CuS for enhanced light-assisted OER electrocatalysis.

Dalton Trans 2021 Apr;50(16):5530-5539

School of Materials Science and Engineering, Liaocheng University, Shandong, 252059, China.

In order to harvest more light wavelengths to improve the light-assisted electrochemical water splitting capacity, we developed a novel heterostructure of three-dimensional (3D) flower-like CuS architecture with accompanying SnS2 nanoparticles and reduced graphene oxide (rGO) aerogel for outstanding light-assisted electrocatalytic OER performance and good stability. The excellent catalytic kinetics, effective capturing of visible light, and rapid charge transfer of the CuS/SnS2/rGO (CSr) heterostructure were demonstrated. The overpotential (264 mV@10 mA cm-2) under light-assisted conditions is 20% lower than that under light-chopped conditions. SnS2 can harvest more light wavelengths and this boosts its intrinsic activity. However, with the increase of the SnS2 content, the OER activity decreases. The combination of the CS heterostructure and the rGO conductive aerogel achieves rapid charge transfer. Furthermore, the possible mechanism of the light-assisted electrocatalytic OER was also proposed. Overall, this work provides new insights into the simple and scalable fabrication of a highly efficient, low-cost, and stable non-noble-metal-based electrocatalyst.
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http://dx.doi.org/10.1039/d1dt00271fDOI Listing
April 2021

MicroRNA governs bistable cell differentiation and lineage segregation via a noncanonical feedback.

Mol Syst Biol 2021 04;17(4):e9945

Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, USA.

Positive feedback driven by transcriptional regulation has long been considered a key mechanism underlying cell lineage segregation during embryogenesis. Using the developing spinal cord as a paradigm, we found that canonical, transcription-driven feedback cannot explain robust lineage segregation of motor neuron subtypes marked by two cardinal factors, Hoxa5 and Hoxc8. We propose a feedback mechanism involving elementary microRNA-mRNA reaction circuits that differ from known feedback loop-like structures. Strikingly, we show that a wide range of biologically plausible post-transcriptional regulatory parameters are sufficient to generate bistable switches, a hallmark of positive feedback. Through mathematical analysis, we explain intuitively the hidden source of this feedback. Using embryonic stem cell differentiation and mouse genetics, we corroborate that microRNA-mRNA circuits govern tissue boundaries and hysteresis upon motor neuron differentiation with respect to transient morphogen signals. Our findings reveal a previously underappreciated feedback mechanism that may have widespread functions in cell fate decisions and tissue patterning.
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http://dx.doi.org/10.15252/msb.20209945DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8062999PMC
April 2021

Piccolo is essential for the maintenance of mouse retina but not cochlear hair cell function.

Aging (Albany NY) 2021 Apr 21;13(8):11678-11695. Epub 2021 Apr 21.

School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan 250100, China.

Piccolo is a presynaptic protein with high conservation among different species, and the expression of Piccolo is extensive in vertebrates. Recently, a small fragment of Piccolo (Piccolino), arising due to the incomplete splicing of intron 5/6, was found to be present in the synapses of retinas and cochleae. However, the comprehensive function of Piccolo in the retina and cochlea remains unclear. In this study, we generated knockout mice using CRISPR-Cas9 technology to explore the function of Piccolo. Unexpectedly, whereas no abnormalities were found in the cochlear hair cells of the mutant mice, significant differences were found in the retinas, in which two layers (the outer nuclear layer and the outer plexiform layer) were absent. Additionally, the amplitudes of electroretinograms were significantly reduced and pigmentation was observed in the fundoscopy of the mutant mouse retinas. The expression levels of Bassoon, a homolog of Piccolo, as well as synapse-associated proteins CtBP1, CtBP2, Kif3A, and Rim1 were down-regulated. The numbers of ribbon synapses in the retinas of the mutant mice were also reduced. Altogether, the phenotype of -/- mice resembled the symptoms of retinitis pigmentosa (RP) in humans, suggesting might be a candidate gene of RP and indicates knockout mice are a good model for elucidating the molecular mechanisms of RP.
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http://dx.doi.org/10.18632/aging.202861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109093PMC
April 2021

Inhibitory Activity of Pyrroloisoxazolidine Derivatives against .

Biomed Res Int 2021 13;2021:8889247. Epub 2021 Mar 13.

School of Pharmacy, Nantong University, Nantong 226001, China.

The obligate intracellular bacterium is a group of worldwide human pathogens that can lead to serious reproductive problems. The frequent clinical treatment failure promoted the development of novel antichlamydial agents. Here, we firstly reported a group of pyrroloisoxazolidine-inhibited in a dose-dependent manner . Among them, compounds 1 and 2 exhibited the strongest inhibitory activity with IC values from 7.25 to 9.73 M. The compounds disturbed the whole intracellular life cycle of , mainly targeting the middle reticulate body proliferation stages. Besides, the compounds partially inhibited the chlamydial infection by reducing elementary body infectivity at high concentration. Our findings suggest the potential of pyrroloisoxazolidine derivatives as promising lead molecules for the development of antichlamydial agents.
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http://dx.doi.org/10.1155/2021/8889247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7984888PMC
March 2021

Skewed Th17/Treg balance during progression and malignant transformation of oral submucous fibrosis.

Oral Dis 2021 Mar 22. Epub 2021 Mar 22.

Hunan Key Laboratory of Oral Health Research & Hunan 3D, Printing Engineering Research Center of Oral Care & Hunan Clinical Research Center of Oral Major Diseases and Oral Health Xiangya Stomatological Hospital & Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China.

Objectives: The aim of our study was to determine the impact of Th17/Treg imbalance on the progression and malignant transformation of oral submucosal fibrosis (OSF).

Materials And Methods: To assess Th17 and Treg expression, overall 52 peripheral blood samples from OSF, oral squamous cell carcinoma (OSCC) patients and healthy donors were analyzed by flow cytometry. 30 normal oral mucosa 72 OSF and 90 OSCC samples were analyzed by immunohistochemistry.

Results: In peripheral blood samples, in OSCC with OSF, Th17 and Treg expression were significantly higher than those in OSF and OSCC without OSF. As confirmed by immunohistochemistry. During OSF progression, Th17 and Th17/Treg ratio showed an increasing trend, while Treg expression showed a decreasing trend. Treg expression were significantly higher in OSCC with OSF than in OSF and OSCC without OSF. Whereas, the Th17/Treg ratio was significantly lower in OSCC with OSF. Treg expression were significantly correlated with smoking and clinical stage. Th17/Treg ratio was significantly associated with tumor size, lymph node metastasis and clinical stage. A low Th17/Treg ratio was significantly associated with poor prognosis.

Conclusions: Th17/Treg ratio is a potential diagnostic indicator for OSF occurrence and malignant transformation and was an independent prognostic factor for OSCC.
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http://dx.doi.org/10.1111/odi.13853DOI Listing
March 2021

Protective Effects of on Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting NF-κB and Activating Nrf2/HO-1 Signaling Pathways.

Front Pharmacol 2020 29;11:591836. Epub 2021 Jan 29.

College of Veterinary Medicine, Jilin University, Changchun, China.

Pterostilbene (PTER) is a kind of stilbene compound with biological activity isolated from plants such as red sandalwood, blueberry and grape. It has anti-tumor, anti-bacterial, anti-oxidation and other pharmacological activities. However, the underlying mechanism of the protective effect of PTER on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remained not clarified. In this study, LPS was used to establish a mouse model of ALI. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells, and the wet-to-dry weight ratio of the lungs was measured. The activities of myeloperoxidase (MPO), antioxidant indexes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and oxidation index such as malondialdehyde (MDA) in lung tissues of mice were measured by the corresponding kits. The levels of Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), TNF-α, IL-6 and IL-1β in lung tissues of mice were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activities of Nrf2, HO-1, p-p65 and -IκB were determined by western blotting. The results showed that the model of LPS-induced ALI was successfully replicated, and it was found that PTER could significantly improve the pathological degree of ALI such as sustained the integrity of the lung tissue structure, alleviated pulmonary interstitial edema and alveolar wall thickening, reduced infiltrated inflammatory cells. PTER could decrease the number of inflammatory cells and obviously inhibit the increase of W/D ratio caused by LPS. PTER could also significantly reduce LPS-induced MPO and MDA, and increase LPS-decreased SOD, CAT and GSH-Px in the lungs. In addition, it was also found that PTER has the ability to decrease LPS-induced production of COX-2, iNOS, TNF-α, IL-6 and IL-1β. The underlying mechanism involved in the protective effect of PTER on ALI were via activating Nrf2 and HO-1, and inhibiting the phosphorylation of p65 and IκB. These results suggested that PTER can protect LPS-induced ALI in mice by inhibiting inflammatory response and oxidative stress, which provided evidence that PTER may be a potential therapeutic candidate for LPS-induced ALI intervention.
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http://dx.doi.org/10.3389/fphar.2020.591836DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901969PMC
January 2021

Cartilage oligomeric matrix protein is an endogenous β-arrestin-2-selective allosteric modulator of AT1 receptor counteracting vascular injury.

Cell Res 2021 Jan 28. Epub 2021 Jan 28.

Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University; Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, 100191, China.

Compelling evidence has revealed that biased activation of G protein-coupled receptor (GPCR) signaling, including angiotensin II (AngII) receptor type 1 (AT1) signaling, plays pivotal roles in vascular homeostasis and injury, but whether a clinically relevant endogenous biased antagonism of AT1 signaling exists under physiological and pathophysiological conditions has not been clearly elucidated. Here, we show that an extracellular matrix protein, cartilage oligomeric matrix protein (COMP), acts as an endogenous allosteric biased modulator of the AT1 receptor and its deficiency is clinically associated with abdominal aortic aneurysm (AAA) development. COMP directly interacts with the extracellular N-terminus of the AT1 via its EGF domain and inhibits AT1-β-arrestin-2 signaling, but not Gq or Gi signaling, in a selective manner through allosteric regulation of AT1 intracellular conformational states. COMP deficiency results in activation of AT1a-β-arrestin-2 signaling and subsequent exclusive AAA formation in response to AngII infusion. AAAs in COMP or ApoE mice are rescued by AT1a or β-arrestin-2 deficiency, or the application of a peptidomimetic mimicking the AT1-binding motif of COMP. Explorations of the endogenous biased antagonism of AT1 receptor or other GPCRs may reveal novel therapeutic strategies for cardiovascular diseases.
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http://dx.doi.org/10.1038/s41422-020-00464-8DOI Listing
January 2021

Transformation of Two Cases of Lung Adenocarcinoma into Pulmonary Sarcomatoid Carcinoma following Treatment.

Can Respir J 2021 2;2021:6661772. Epub 2021 Jan 2.

Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Soochow University, Suzhou, China.

Accumulating evidence shows that histologic transformation is involved in the drug resistance of lung cancer. Moreover, it is common for lung adenocarcinoma to transform into small-cell lung cancer or squamous cell carcinoma; however, clinical cases with sarcomatoid transformation have been rarely reported. Thus, both the diagnosis and treatment of lung adenocarcinoma with sarcomatoid transformation remain difficult. Here, we discuss two patients with lung adenocarcinoma with sarcomatoid transformation-analyzing the diagnosis, clinical features, immunohistochemical characteristics, therapy, and prognosis-with the hope that this report will be used as a reference for future treatment of these patients.
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http://dx.doi.org/10.1155/2021/6661772DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796848PMC
January 2021

Transjugular intrahepatic portosystemic shunt for hepatic sinusoidal obstruction syndrome associated with consumption of Gynura segetum.

BMC Gastroenterol 2021 Jan 10;21(1):26. Epub 2021 Jan 10.

Department of Radiology, Hubei Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, 430022, China.

Background: To evaluate the efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) on hepatic sinusoidal obstruction syndrome (HSOS) associated with consumption of Gynura segetum (GS).

Methods: We retrospectively reviewed 9 consecutive patients with GS-related HSOS who were refractory to supportive treatment and underwent TIPS at our institution between January 2014 and September 2019. The patients were evaluated for safety and efficacy, including TIPS complications and changes in portosystemic pressure gradient (PPG), ascites, total bilirubin, liver size and portal vein diameter.

Results: TIPS procedures were performed successfully in the 9 patients, and no technically-related complications due to the TIPS procedure were recorded. The PPG was improved by TIPS in all patients (mean PPG before TIPS, 30.4 ± 5.2 vs. 13.0 ± 4.1 mm Hg post-TIPS, P = 0.008). One patient who was lost to follow-up, whereas the remaining 8 patients survived with a median follow-up period of 12 months (range 5-39 months). Although the total bilirubin was significantly increased 5-7 days after TIPS compared with that before the procedure (3.57 ± 1.58 vs. 4.82 ± 2.06 mg/dl, P = 0.017), it returned to baseline levels at 1-month follow-up (3.53 ± 2.72 vs. 4.82 ± 2.06 mg/dl, P = 0.401). The patients experienced complete resolution or noticeable reduction of ascites (P < 0.001), significant reduction of liver size (16.7 ± 2.2 vs. 13.7 ± 1.7 cm, P = 0.018), and significant enlargement of the portal trunk (10.7 ± 2.5 vs. 13.4 ± 2.4 mm, P = 0.017) after TIPS compared to the pre-TIPS state.

Conclusion: TIPS may offer a potentially useful treatment for the GS-related HSOS.
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http://dx.doi.org/10.1186/s12876-021-01599-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7798314PMC
January 2021

Sodium molybdate induces heterophil extracellular traps formation in chicken.

Ecotoxicol Environ Saf 2021 Mar 8;210:111886. Epub 2021 Jan 8.

College of Life Sciences and Engineering, Foshan University, Foshan 528225, Guangdong, PR China. Electronic address:

Molybdenum (Mo) is not only an important rare metal that is widely used in industrial production but also an essential trace element for plants and animals. Nevertheless, in Mo polluted areas, excess Mo intake will not only cause gout in humans but also cause diarrhea in livestock and growth inhibition of chickens. Heterophils extracellular traps (HETs) are an important way to clear pathogens in the innate immune system of the chicken. However, the effects of Mo on the innate immune responses of HETs formation in chicken, and the mechanism undergoing this phenomenon remain unknown. In the study, we firstly aim to investigate the effects of sodium molybdate (NaMoO) on chicken HETs formation in vitro, and further to explore its related metabolic requirements and molecular mechanisms. Chicken heterophils were cultured with NaMoO, and NaMoO-induced HETs structures were analyzed by confocal microscopy. Moreover, NaMoO-induced HETs were quantified by Quant-iT PicoGreen® dsDNA Assay kits and fluorescence microplate. It has been shown that NaMoO truly triggered HETs-like structures that were composed of DNA decorated with citrullinated histone 3 (citH3) and elastase. The inhibitors of NADPH oxidase, ERK and p38 MAPK signaling pathway significantly reduced NaMoO-induced HETs formation. Further experiments on energy metabolism involving NaMoO-induced HETs formation showed that NaMoO-induced HETs release was relevant to glucose, and the inhibitors of glycolysis including 3PO, AZD23766 and 3-Bromopyuvic acid, the inhibitors of glucose transport including STF31 and Ritonavir and NSC23766 significantly decreased NaMoO-induced HETs formation In summary, these results demonstrate that Mo does induce chicken HETs formation in vitro, and the formation of HETs is a process relying on glucose transport 1 (GLUT1),glucose transport 4 (GLUT4), glycolysis, and ROS production depended on the activation of NADPH oxidase, ERK and p38 signaling pathways, which also reflects the early innate immune responses of chicken against excessive molybdenum intake.
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http://dx.doi.org/10.1016/j.ecoenv.2020.111886DOI Listing
March 2021

Diacetoxyscirpenol-induced heterophil extracellular traps contribute to the immune toxicity of liver injury in chickens.

Food Chem Toxicol 2021 Feb 24;148:111926. Epub 2020 Dec 24.

School of Life Sciences and Engineering, Foshan University, Foshan, 528225, Guangdong Province, China. Electronic address:

Diacetoxyscirpenol (DAS) is one kind of type A trichothecene mycotoxin which produced by Fusarium species which contaminates agricultural crops and food. DAS attracts particular attention because of the strong toxicity. Heterophil extracellular traps (HETs) is a defense mechanism in the chicken innate immune. In this study, we firstly examine the effects and molecular mechanisms of DAS on HETs release, and then investigate the immune toxicity of DAS-induced HETs on chicken liver. HETs structures were observed by immunofluorescence staining and mechanisms were investigated by fluorescence microplate and Western blot. The results showed DAS triggered HETs formation which consists of chromatin decorated with citrullinated histone 3 (citH3) and elastase. Glycolysis was confirmed to be involved in this process and the inhibitors of NADPH oxidase, ERK, p38 MAPK-signaling pathways and glycolysis significantly decreased HETs formation. Moreover, investigation in vivo showed DAS significantly increased HETs formation in serum and DNase I (a standard degradative agent of HETs) significantly decreased the ALT and AST levels and ameliorated DAS-caused inflammatory cell infiltration of liver. In conclusion, this study proves that DAS-induced HETs formation plays an immune toxicity role in chicken liver injury and these results provide a new therapeutic target for DAS-induced liver injury in chickens.
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http://dx.doi.org/10.1016/j.fct.2020.111926DOI Listing
February 2021

A mathematical model for understanding synergistic regulations and paradoxical feedbacks in the shoot apical meristem.

Comput Struct Biotechnol J 2020 21;18:3877-3889. Epub 2020 Nov 21.

Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States.

The shoot apical meristem (SAM) is the primary stem cell niche in plant shoots. Stem cells in the SAM are controlled by an intricate regulatory network, including negative feedback between WUSCHEL (WUS) and CLAVATA3 (CLV3). Recently, we identified a group of signals, Epidermal Patterning Factor-Like (EPFL) proteins, that are produced at the peripheral region and are important for SAM homeostasis. Here, we present a mathematical model for the SAM regulatory network. The model revealed that the SAM uses EPFL and signals such as HAIRY MERISTEM from the middle in a synergistic manner to constrain both and . We found that interconnected negative and positive feedbacks between WUS and CLV3 ensure stable expression in the SAM when facing perturbations, and the positive feedback loop also maintains distinct cell populations containing and cells in the apical-basal direction. Furthermore, systematic perturbations of the parameters revealed a tradeoff between optimizations of multiple patterning features. Our results provide a holistic view of the regulation of SAM patterning in multiple dimensions. They give insights into how integrates signals from lateral and apical-basal axes to control the SAM patterning, and they shed light into design principles that may be widely useful for understanding regulatory networks of stem cell niche.
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http://dx.doi.org/10.1016/j.csbj.2020.11.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7720093PMC
November 2020

New treatment of bronchopleural fistula following surgical resection of the dorsal segment of the left lower lobe: A case report.

Thorac Cancer 2021 02 10;12(3):382-386. Epub 2020 Dec 10.

Department of Respiratory Medicine, The First Affiliated Hospital of Soochow University, Suzhou, China.

Anatomical segment-based or subsegmental resection for early lung cancer surgery has been used in selected cases, although postoperative complications of bronchopleural fistula sometimes occur. Persistent air leaks can cause complications such as empyema and aspiration pneumonia, resulting in prolonged patient hospitalization. The traditional treatment for postoperative bronchopleural fistula is reoperation, but the advent of bronchoscopic interventional therapy usually prevents patients from needing a second operation. This article details a case of thoracoscopic segmentectomy of the left lower lung dorsal segment resulting in residual subsegmental pleural fistula, and because the use of pleural adhesives made the patient's fistula inappropriate for surgical repair, we finally used bronchoscopic injury of the airway mucosa combined with an absorbable gelatin sponge and an autologous blood closure method for successful treatment.
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http://dx.doi.org/10.1111/1759-7714.13734DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862795PMC
February 2021

Tracing the driving forces responsible for the remarkable infectivity of 2019-nCoV: 1. Receptor binding domain in its bound and unbound states.

Phys Chem Chem Phys 2020 Dec;22(48):28277-28285

State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory for Catalytic Conversion of Carbon Resources, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.

The pandemic of COVID-19 has posed an urgent need to learn the dynamics of the virus and the mechanism of its contagion of host cells. By means of molecular dynamics simulations, this work addressed the behavior of 2019-nCoV in two aspects: the binding affinity of its receptor binding domain (RBD) with ACE2, and its potential conformation preferences in its unbound state. The results showed that the RBD of 2019-nCov bound much stronger with ACE2 than that of SARS-CoV due to a better organized hydrogen bond network between the former pair with most of the residues at the contact interface sharing the responsibility to hold the pair tightly. This is in contrast to the case of SARS-CoV, which strongly relied on the residues at the ends of the cleft. In its unbound state, the RBD of 2019-nCoV was found to fold part of its receptor binding motif (RBM) into a helical conformation and flip into a concave to minimize its contact with the external environment. This has the biological implication that the virus may achieve higher translational motion in the condensed phase and have a higher chance of survival by avoiding capture by the immune system before reaching its target receptor.
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http://dx.doi.org/10.1039/d0cp04435kDOI Listing
December 2020

Sodium Butyrate Alleviates Lipopolysaccharide-Induced Inflammatory Responses by Down-Regulation of NF-κB, NLRP3 Signaling Pathway, and Activating Histone Acetylation in Bovine Macrophages.

Front Vet Sci 2020 5;7:579674. Epub 2020 Nov 5.

College of Life Sciences and Engineering, Foshan University, Foshan, China.

Sodium butyrate is the sodium salt of butyric acid, which possesses many biological functions including immune system regulation, anti-oxidant and anti-inflammatory ability. The present study was designed to elucidate the anti-inflammatory effects and mechanisms of sodium butyrate on lipopolysaccharide (LPS)-stimulated bovine macrophages. The effect of sodium butyrate on the cell viability of bovine macrophages was assayed by using the CCK-8 kit. Quantitative real-time PCR (qRT-PCR) was used to detect the gene expression of interleukin-6 (IL-6), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and inducible Nitric Oxide Synthase (iNOS). NF-κB, NLRP3 signaling pathway, and histone deacetylase were detected by western blotting. The results showed that sodium butyrate had no significant effect on cell viability at 0-1 mM, and inhibited LPS-induced IL-6, IL-1β, COX-2, and iNOS expression. Moreover, sodium butyrate suppressed LPS (5 μg/ml)-stimulated the phosphorylation of IκB and p65, inhibited the deacetylation of histone H3K9, and has also been found to inhibit protein expression in NLRP3 inflammasomes. Thus, our finding suggested that sodium butyrate relieved LPS-induced inflammatory responses in bovine macrophage by inhibiting the canonical NF-κB, NLRP3 signaling pathway, and histone decetylation, which might be helpful to prevent cow mastitis.
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http://dx.doi.org/10.3389/fvets.2020.579674DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674777PMC
November 2020

Alpinetin prevents inflammatory responses in OVA-induced allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways in mice.

Int Immunopharmacol 2020 Dec 8;89(Pt A):107073. Epub 2020 Oct 8.

Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, Jilin Province, PR China. Electronic address:

Allergic asthma is the most common type of asthma which characterized by inflammatory responses of the airways. Alpinetin, a flavonoid compound derived from the ginger family of medicinal herbs, possesses various biological properties including anti-inflammatory, anti-oxidant and other medical effects. In this study, we aimed to evaluate the effects of alpinetin on OVA-induced allergic asthma, and further to examine its molecular mechanisms underlying these processes in vivo and in vitro. Mice were sensitized and challenged with OVA to build allergic asthma model in vivo. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells analysis and lung tissues were examined for histopathological examination. The levels of IL-5, IL-13, IL-4, IgE, TNF-α, IL-6 and IL-1β were determined by the respective ELISA kits. The PI3K/AKT/NF-κB and HO-1 signaling pathways were examined by western blot analysis. The results showed that alpinetin significantly ameliorated OVA-induced pathologic changes of lungs, such as decreasing massive inflammatory cell infiltration and mucus hypersecretion, and reduced the number of inflammatory cells in BALF. Alpinetin also decreased the OVA-induced levels of IL-4, IL-5, IL-13 and IgE. Furthermore, alpinetin inhibited OVA-induced phosphorylation of p65, IκB, PI3K and AKT, and the activity of HO-1 in vivo. More importantly, these anti-inflammatory effects and molecular mechanisms of alpinetin has also been confirmed in LPS-stimulated RAW 264.7 macrophages in vitro. In conclusion, above results indicate that alpinetin exhibites a potent anti-inflammatory activity in allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways, which would be used as a promising therapy agent for allergic asthma.
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http://dx.doi.org/10.1016/j.intimp.2020.107073DOI Listing
December 2020

Deltamethrin transformation by Bacillus thuringiensis and the associated metabolic pathways.

Environ Int 2020 12 6;145:106167. Epub 2020 Oct 6.

Institute of Orthopedic Diseases and Department of Bone and Joint Surgery, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China. Electronic address:

The biological toxicity of deltamethrin at molecular level has been investigated, whereas, the proteome responsive mechanisms of cells under deltamethrin stress at the phylogenetic level are not clear. The proteome expression, transformation-related pathway and regulatory network of Bacillus thuringiensis during the process of deltamethrin transformation were explored using proteomics and metabolomics approaches in the present study. The results showed that deltamethrin was effectively removed by B. thuringiensis within 48 h. The stress responses of B. thuringiensis were activated to resist deltamethrin stress, with significant differential expression of proteins that were primarily involved in the synthesis of DNA and shock proteins, endospore formation, carbon metabolism. The expression patterns of ribosomal proteins confirmed that the transcription and translation of DNA, and biosynthesis of heat shock proteins were inhibited as deltamethrin transformation. The synthesis of oxaloacetate and acetyl-CoA were also hindered, resulting in downregulated expression of carbohydrate metabolism, TCA cycle and energy metabolism. Meanwhile, endospore formation and germination were promoted to resist oxidative stress induced by deltamethrin. These findings imparted novel insight to elucidate underlying stress response mechanisms of the organism under target contaminants stress, and the interaction between deltamethrin transformation and cellular metabolism at the pathway and network levels.
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http://dx.doi.org/10.1016/j.envint.2020.106167DOI Listing
December 2020

Pterostilbene Exerts Hepatoprotective Effects through Ameliorating LPS/D-Gal-Induced Acute Liver Injury in Mice.

Inflammation 2021 Apr 2;44(2):526-535. Epub 2020 Oct 2.

College of Veterinary Medicine, Jilin University, Changchun, 130062, Jilin, People's Republic of China.

Acute liver injury (ALI) refers to abnormalities in liver function caused by various causes and accompanied by poor prognosis and high mortality. Common predisposing factors for the disease are viral hepatitis, bacteria, alcohol, and certain hepatotoxic drugs. Inflammatory response and oxidative stress are critical for the pathogenesis of ALI. Pterostilbene (Pte), a natural polyphenol product extracted from blueberries and grapes, has been reported that exerted multiple biological activities, including antioxidative, anti-inflammatory, anti-carcinogenic, and anti-apoptotic properties. However, there is very little data showing the hepatoprotective effect of Pte on lipopolysaccharide/D-galactosamine (LPS/D-Gal)-induced ALI in mice. In this study, the possible protective effect and potential mechanisms of Pte on ALI are being investigated. It has been found that Pte markedly ameliorates LPS/D-Gal-induced inflammatory infiltration, hemorrhage, and dissociation of the hepatic cord, reducing the myeloperoxidase (MPO) activity in liver tissues and serum levels of alanine transaminase (ALT) and aspartate aminotransferase (AST) in ALI. Pte also inhibits LPS/D-Gal-induced secretion of pro-inflammatory cytokine tumor necrosis factor-a (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β) in liver tissues. Furthermore, the western blot analysis reveals that LPS/D-Gal-activated nuclear factor-kappa B (NF-κB) is significantly inhibited by Pte, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) are upregulated by Pte. In conclusion, our results suggest that Pte exerts anti-inflammatory and antioxidative effects, which might contribute to ameliorating LPS/D-Gal-induced ALI in mice. Pte has the potential to be a preventive hepatoprotective agent.
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http://dx.doi.org/10.1007/s10753-020-01349-zDOI Listing
April 2021

Differential expression of programmed death-1 and its ligand, programmed death ligand-1 in oral squamous cell carcinoma with and without oral submucous fibrosis.

Arch Oral Biol 2020 Nov 17;119:104916. Epub 2020 Sep 17.

Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan 410008, PR China. Electronic address:

Objective: The aim of our study was to investigate the expression of programmed death ligand-1 (PD-L1)/programmed death-1 (PD-1) between oral squamous cell carcinoma (OSCC) patients with and without oral submucous fibrosis (OSF), and its correlation with clinic-pathologic features and its prognostic value.

Methods: PD-L1 and PD-1 expression was evaluated by immunohistochemical staining, double immunofluorescent staining and real-time PCR, and the correlation of PD-L1/PD-1 expression with clinical outcome was assessed.

Results: The level of PD-L1 expression was significantly higher in OSCC with OSF than in OSCC without OSF (p = 0.006). Moreover, PD-L1 expression was strongly correlated with lymph node metastasis (p = 0.016), and advanced tumor stage (p = 0.030). Increased PD-L1 expression was positively correlated with the incidence of OSCC with OSF (p = 0.006, p = 0.008, respectively). PD-L1 expression was an independent marker of unfavorable prognosis (p = 0.035, p = 0.048, respectively). High PD-L1 expression had a significantly worse outcome in OSCC patients with OSF (p = 0.014). Double immunofluorescent staining showed that OSCC with OSF were more strongly expressed both PD-L1 and PD-1 than OSCC without OSF. Moreover, the expression of PD-L1 were upregulated in OSCC tissues than normal control (p = 0.0422), and both PD-L1 and PD-1 was significantly higher in OSCC with OSF than OSCC without OSF tissues (p = 0.0043 and, p = 0.0012, respectively).

Conclusions: The present study suggested that PD-L1 may be an unfavorable indicator for prognosis. PD-L1/PD-1 signaling might play an important role in the malignant transformation of OSF, and targeting PD-L1/PD-1 signaling may be a new therapeutic strategy for OSCC, especially in OSCC patients with OSF.
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http://dx.doi.org/10.1016/j.archoralbio.2020.104916DOI Listing
November 2020

The silver lining of COVID-19: estimation of short-term health impacts due to lockdown in the Yangtze River Delta region, China.

Geohealth 2020 Jul 7:e2020GH000272. Epub 2020 Jul 7.

School of Environmental and Chemical Engineering Shanghai University Shanghai China.

The outbreak of COVID-19 in China has led to massive lockdowns in order to reduce the spread of the epidemic and control human-to-human transmission. Subsequent reductions in various anthropogenic activities have led to improved air quality during the lockdown. In this study, we apply a widely used exposure-response function to estimate the short-term health impacts associated with PM changes over the Yangtze River Delta (YRD) region due to COVID-19 lockdown. Concentrations of PM during lockdown period reduced by 22.9% to 54.0% compared to pre-lockdown level. Estimated PM-related daily premature mortality during lockdown period is 895 (95% confidential interval: 637-1081), which is 43.3% lower than pre-lockdown period and 46.5% lower compared with averages of 2017-2019. According to our calculation, total number of avoided premature death associated PM reduction during the lockdown is estimated to be 42.4 thousand over the YRD region, with Shanghai, Wenzhou, Suzhou (Jiangsu province), Nanjing, and Nantong being the top five cities with largest health benefits. Avoided premature mortality is mostly contributed by reduced death associated with stroke (16.9 thousand, accounting for 40.0%), ischemic heart disease (14.0 thousand, 33.2%) and chronic obstructive pulmonary disease (7.6 thousand, 18.0%). Our calculations do not support or advocate any idea that pandemics produce a positive note to community health. We simply present health benefits from air pollution improvement due to large emission reductions from lowered human and industrial activities. Our results show that continuous efforts to improve air quality are essential to protect public health, especially over city-clusters with dense population.
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http://dx.doi.org/10.1029/2020GH000272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7361223PMC
July 2020

Fumonisin B triggers the formation of bovine neutrophil extracellular traps.

Toxicol Lett 2020 Oct 10;332:140-145. Epub 2020 Jul 10.

College of Life Science and Engineering, Foshan University, Foshan, Guangdong, 528231, People's Republic of China. Electronic address:

Fumonisin B (FB) is a congener of fumonisins produced by Fusarium species that may be found as corn contaminants threatening health of humans and animals. FB causes a variety of toxicity effects, including hepatotoxic, nephrotoxic and cytotoxic effects. However, detailed mechanisms associated with FB immunotoxicity in neutrophils are still unclear. To accomplish this, we utilized neutrophils to study the mechanisms of FB immunotoxicity. In the current study, we found that FB induced the formation of neutrophil extracellular traps (NETs), increased reactive oxygen species (ROS) levels, and decreased SOD and CAT activities. Concurrently, FB treatment led to the concentration-dependent phosphorylation of ERK-1/2 and p38 in neutrophils. Moreover, we demonstrated that FB-induced NET formation was dependent of NADPH oxidase activity. Pretreatment of neutrophils with DPI, U0126 and SB202190 significantly reduced ROS generation, and prevented NET formation, further suggesting that ROS dependent activation of ERK 1/2 and p38 pathways, which possibly mediate FB-induced NET release in neutrophils. Thus, NET formation and ROS production could be attributed to FB immunotoxicity, which might enrich the toxicological mechanisms of FB.
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http://dx.doi.org/10.1016/j.toxlet.2020.07.006DOI Listing
October 2020

Removal of starch granule-associated proteins promotes α-amylase hydrolysis of rice starch granule.

Food Chem 2020 Nov 13;330:127313. Epub 2020 Jun 13.

Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.

Starch granule-surface proteins (SGSPs) and granule-channel proteins (SGCPs) are granule-associated proteins (SGAPs), which have been found to be distributed on the surface and channels of starch granules, respectively. To investigate the impacts of SGAPs on α-amylase hydrolysis of starch, SGCPs or SGAPs of waxy, low and high amylose rice starches were removed. Removal of SGAPs or SGCPs greatly increased hydrolysis rate of rice starches. Meanwhile, these granules incurred a greater number and size of pores on their surfaces during hydrolysis. Compared to low and high amylose starches, waxy starch before and after removing SGAPs exhibited a higher hydrolysis rate. Rice starch hydrolysis began with enlargement of cavity and channels both horizontally and vertically. XRD analysis revealed that removal of SGAPs decreased relative crystallinity (RC) of starch and advanced changes in RC during hydrolysis process. This study provides new information about the role of SGAPs in the mechanisms of α-amylase hydrolysis.
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http://dx.doi.org/10.1016/j.foodchem.2020.127313DOI Listing
November 2020

Air quality changes during the COVID-19 lockdown over the Yangtze River Delta Region: An insight into the impact of human activity pattern changes on air pollution variation.

Sci Total Environ 2020 Aug 11;732:139282. Epub 2020 May 11.

Department of Civil Engineering, University of Nottingham Malaysia, Semenyih 43500, Selangor, Malaysia. Electronic address:

The outbreak of COVID-19 has spreaded rapidly across the world. To control the rapid dispersion of the virus, China has imposed national lockdown policies to practise social distancing. This has led to reduced human activities and hence primary air pollutant emissions, which caused improvement of air quality as a side-product. To investigate the air quality changes during the COVID-19 lockdown over the YRD Region, we apply the WRF-CAMx modelling system together with monitoring data to investigate the impact of human activity pattern changes on air quality. Results show that human activities were lowered significantly during the period: industrial operations, VKT, constructions in operation, etc. were significantly reduced, leading to lowered SO, NO, PM and VOCs emissions by approximately 16-26%, 29-47%, 27-46% and 37-57% during the Level I and Level II response periods respectively. These emission reduction has played a significant role in the improvement of air quality. Concentrations of PM, NO and SO decreased by 31.8%, 45.1% and 20.4% during the Level I period; and 33.2%, 27.2% and 7.6% during the Level II period compared with 2019. However, ozone did not show any reduction and increased greatly. Our results also show that even during the lockdown, with primary emissions reduction of 15%-61%, the daily average PM concentrations range between 15 and 79 μg m, which shows that background and residual pollutions are still high. Source apportionment results indicate that the residual pollution of PM comes from industry (32.2-61.1%), mobile (3.9-8.1%), dust (2.6-7.7%), residential sources (2.1-28.5%) in YRD and 14.0-28.6% contribution from long-range transport coming from northern China. This indicates that in spite of the extreme reductions in primary emissions, it cannot fully tackle the current air pollution. Re-organisation of the energy and industrial strategy together with trans-regional joint-control for a full long-term air pollution plan need to be further taken into account.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139282DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211667PMC
August 2020

Deciphering the Structural Diversity and Classification of the Mobile Tigecycline Resistance Gene (X)-Bearing Plasmidome among Bacteria.

mSystems 2020 Apr 28;5(2). Epub 2020 Apr 28.

College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China

The emergence of novel plasmid-mediated resistance genes constitutes a great public concern. Recently, mobile (X) variants were reported in diverse pathogens from different sources. However, the diversity of (X)-bearing plasmids remains largely unknown. In this study, the phenotypes and genotypes of all the (X)-positive tigecycline-resistant strains isolated from a slaughterhouse in China were characterized by antimicrobial susceptibility testing, conjugation, pulsed-field gel electrophoresis with S1 nuclease (S1-PFGE), and PCR. The diversity and polymorphism of (X)-harboring strains and plasmidomes were investigated by whole-genome sequencing (WGS) and single-plasmid-molecule analysis. Seventy-four (X4)-harboring strains and one (X6)-bearing strain were identified. The (X4)-bearing elements in 27 strains could be transferred to the recipient strain via plasmids. All (X4)-bearing plasmids isolated in this study and 15 (X4)-bearing plasmids reported online were analyzed. (X4)-bearing plasmids ranged from 9 to 294 kb and were categorized as ColE2-like, IncQ, IncX1, IncA/C2, IncFII, IncFIB, and hybrid plasmids with different replicons. The core (X4)-bearing genetic contexts were divided into four major groups: IS-(X4)-, △IS--(X4)-IS, IS-(X4)-IS--, and -(X4)-IS----IS-- Tandem repeats of (X4) were universally mediated by IS Different (X)-bearing strains existed in the same microbiota. Reorganization of (X4)-bearing multidrug resistance plasmids was found to be mediated by IS and other homologous regions. Finally, single-plasmid-molecule analysis captured the heterogenous state of (X4)-bearing plasmids. These findings significantly expand our knowledge of the (X)-bearing plasmidome among microbiotas, which establishes a baseline for investigating the structure and diversity of human, animal, and environmental tigecycline resistomes. Characterization of (X) genes among different microbiotas should be performed systematically to understand the evolution and ecology. Tigecycline is an expanded-spectrum tetracycline used as a last-resort antimicrobial for treating infections caused by superbugs such as carbapenemase-producing or colistin-resistant pathogens. Emergence of the plasmid-mediated mobile tigecycline resistance gene (X4) created a great public health concern. However, the diversity of (X4)-bearing plasmids and bacteria remains largely uninvestigated. To cover this knowledge gap, we comprehensively identified and characterized the (X)-bearing plasmidome in different sources using advanced sequencing technologies for the first time. The huge diversity of (X4)-bearing mobile elements demonstrates the high level of transmissibility of the (X4) gene among bacteria. It is crucial to enhance stringent surveillance of (X) genes in animal and human pathogens globally.
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http://dx.doi.org/10.1128/mSystems.00134-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190383PMC
April 2020

Elevated systemic inflammatory responses, factors associated with physical and mental quality of life, and prognosis of hepatocellular carcinoma.

Aging (Albany NY) 2020 03 7;12(5):4357-4370. Epub 2020 Mar 7.

Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

Impaired quality of life (QOL) is common in hepatocellular carcinoma (HCC) patients. In this study, we used a large hospital-based multiethnic HCC patient cohort to systematically identify factors associated with QOL and investigate the prognostic value of QOL.The Short Form-12 questionnaire was used to assess QOL. The Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were categorized into three groups (low, medium, and high) and ordered logistic regression analysis was used to analyze the association of PCS and MCS scores with patient characteristics. The association of PCS and MCS scores with mortality was assessed by Cox regression analysis.Notably, a panel of elevated systemic inflammatory response markers was associated with poor QOL. Other significant factors associated with QOL included age, liver function, sex, smoking, HCC etiology, and major clinical features. Patients with low (hazard ratio [95% CI], 1.72 [1.36-2.17]) and medium (1.52 [1.23-1.89]) PCS scores exhibited higher risks of death compared to patients with high PCS score. The association of MCS with the risk of death was not significant. These observations were consistent across all the different ethnicities.The identified factors associated with QOL may help clinicians formulate interventions to improve QOL and outcomes in HCC patients.
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http://dx.doi.org/10.18632/aging.102889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7093167PMC
March 2020

Enzyme activity of waste activated sludge extracts.

Water Sci Technol 2019 Nov;80(10):1861-1869

Wastewater treatment and generated biological sludge provide an alternative source of enzymes to conventional industrial production methods. Here, we present a protocol for extracting enzymes from activated sludge using ultrasonication and surfactant treatment. Under optimum conditions, ultrasound disruption of activated sludge gave recovery rates of protease and cellulase enzymes equivalent to 63.1% and ∼100%, respectively. The extracting of enzymes from activated sludge represents a potentially significant, high-value, resource recovery option for biological sludge generated by municipal wastewater treatment.
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http://dx.doi.org/10.2166/wst.2020.002DOI Listing
November 2019

Identification of d-amino acids in tea leaves.

Food Chem 2020 Jul 19;317:126428. Epub 2020 Feb 19.

State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, Anhui, China. Electronic address:

During manufacturing processes and in the storage period of tea, amino acids may undergo enantiomeric isomerization, converting their l- to d-forms. To examine the hypothesis, a method was developed for the analysis of the enantiomers in tea leaves. After enriched by ion-exchange solid-phase extraction, the enantiomeric pairs were separated by a chiral high performance liquid chromatography (HPLC) and subsequently detected and identified by using a high resolution quadrupole time-of-flight mass spectrometry (QTOF MS). Only l-forms of amino acids were found in fresh tea leaves. A total of 11 d-amino acids were found in 19 tea samples, ranging from trace amount to 43 µg/g. The results indicated that the enantioisomerization of amino acids occurred in post-harvest tea leaves, and affected by process conditions and storage time.
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http://dx.doi.org/10.1016/j.foodchem.2020.126428DOI Listing
July 2020

Repertoire of peripheral T cells in patients with oral squamous cell carcinoma.

Oral Dis 2020 Jul 19;26(5):885-893. Epub 2020 Mar 19.

Research Institution of Stomatology, Xiangya Stomatological Hospital & School of Stomatology, Central South University, Changsha, China.

Background: The establishment of adaptive immune responses to neoplasms involves not only the tumour tissue, but also the peripheral blood. We aimed to conduct a preliminary exploration to understand the immune response of T lymphocytes of peripheral blood mononuclear cells (PBMC-Ts) in oral squamous cell carcinoma (OSCC).

Methods: A total of 103 blood samples from OSCC patients and 18 blood samples from healthy donors (HD) were analysed by flow cytometry.

Results: Compared to those in HD, a series of unique features of PBMC-Ts were observed in OSCC patients including a significant increase in CD4+ T cells, a shift from naïve to memory/effector phenotype, an increased frequency of exhausted phenotypes (programmed death-1 [PD-1], T cell Ig and mucin protein-3 [Tim-3] and Tregs), an abundance of Th17s and Tc17s and an imbalance in Th17/Tc17 and Th17/Treg ratios. Furthermore, in OSCC patients, we also found that CD4+ T cells were significantly increased in patients with larger tumours than smaller tumours, memory/effector phenotype and exhausted phenotypes were significantly associated with advanced clinical stage and lymph node metastasis, and the Th17/Treg ratio was associated with early clinical stage and no lymph node metastasis.

Conclusion: PBMC-Ts may be involved in the development and progression of OSCC, which suggested to be a manifestation of an immune response between host and tumour neoantigens.
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http://dx.doi.org/10.1111/odi.13311DOI Listing
July 2020

Key Factors Determining Efficiency of Liquid-Liquid Extraction: Implications from Molecular Dynamics Simulations of Biphasic Behaviors of CyMe-BTPhen and Its Am(III) Complexes.

J Phys Chem B 2020 03 24;124(9):1751-1766. Epub 2020 Feb 24.

CAS Key Laboratory of Nuclear Radiation and Nuclear Techniques, Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.

CyMe-BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline, denoted as L) has been considered as a promising extractant in lanthanide(III)/actinide(III) separation. Vast endeavors in its application put forward a compelling need on the understanding of the underlying mechanism in the liquid-liquid extraction. To address the issue of its dynamics in biphasic systems, we carried out molecular dynamics (MD) simulations of L and its complexes with a heavy f-block metal ion, americium(III) (Am) in "oil"/water binary solvents. Two types of organic phases have been considered, differing in the presence of octanol in the bulk -dodecane or not, and the distribution of the solutes and their interfacial behaviors have been investigated. Two of the key factors that determine the efficiency of a liquid-liquid extraction protocol were delineated and discussed, that is, the appropriate ligand to enhance the lipophilicity of AmL complexes and appropriate way to form ion pairs to minimize the attraction between the complexes and aqueous phase. The simulations showed that the charge states of both ligand and AmL complexes were strongly correlated with their phase behavior, and the migration of neutral species was driven by van der Waals interactions while that of charged species by electrostatic interactions, indicating stronger lipophilicity of the former than the latter. The presence of octanol facilitated the migration of the ligand from the interface to the organic phase via hydrogen bond between its polar head and the ligand or the AmL complexes and constituted a polar core in the organic phase. This work bridged the widely used liquid-liquid extraction technique in chemistry to a fundamental chemical concept, that is, minimization of hydrophilicity and maximization of lipophilicity to facilitate phase transfer from the aqueous phase to the organic phase, and is expected to improve the understanding of dynamics of ligands and their complexes with metal ions and to contribute to the development of efficient protocols for phase transfer of target species.
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http://dx.doi.org/10.1021/acs.jpcb.9b08447DOI Listing
March 2020