Publications by authors named "Fengxia Li"

46 Publications

Antidepressant-like effect and phytochemical profile of supercritical CO₂ extract from .

Pharmazie 2021 Jun;76(6):249-255

Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Bei Jing, China;, Email:

is a condiment, adding much flavor in Chinese food. Also it can be used to treat depression as a Traditional Chinese Medicine (TCM). The study here aimed to evaluate the antidepressant effect between the supercritical CO₂ extract () from and the essential oil extracted by steam distillation (). And chemical compositions of were qualitatively analyzed by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and gas chromatography-mass spectrometry (GC-MS). Compared with , showed a stronger antidepressant-like effect in FST and TST mice. And it also decreased the content of monoamine oxidase (MAO) in the cerebral cortex of stressed mice. A total of 60 compounds were identified in . Among them, 28 compounds were characterized in UPLC-Q-TOF/MS analysis and all are polymethoxyflavones (PMFs). Three main compounds, 3,5,6,7,8,3',4'-heptamethoxyflavone, nobiletin and tangeretin, together account for 66.09% of the total relative peak area. 33 terpenes were identified by GC-MS analysis, such as D-limonene (12.34%), -elemene (8.86%), germacrene D (5.59%) and (Z, E)--farnesene (5.44%). Polymethoflavones and terpenes are the main constituents of responsible for its antidepressant-like effect. The study could stimulate further investigations into the antidepressant effects and mechanism of .
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http://dx.doi.org/10.1691/ph.2021.1408DOI Listing
June 2021

The effects of S-nitrosylation-induced PPARγ/SFRP5 pathway inhibition on the conversion of non-alcoholic fatty liver to non-alcoholic steatohepatitis.

Ann Transl Med 2021 Apr;9(8):684

Gastroenterology Department, Shanxi Provincial People's Hospital, Taiyuan, China.

Background: Peroxisome proliferators-activated receptors γ (PPARγ) and secreted frizzled related protein 5 (SFRP5) are abnormally expressed in liver cells. But their role in the transformation of non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH) remains to be studied. We aimed to explore the role of S-nitrosylation (SNO) in the conversion of NAFL to NASH via the peroxisome PPARγ/SFRP5 pathway.

Methods: A normal diet and methionine-choline deficient diet were used to construct the NAFL and NASH mouse models, respectively. The differences between the SNO of PPARγ in both models were measured by irreversible biotinylation. Quantitative reverse transcription PCR (qRT-PCR) and Western blotting were used to detect the effect of SNO on the expression of PPARγ messageRNA (mRNA) and protein in L02 hepatocytes. Nubiscan software, luciferase reporter gene, and chromatin immunoprecipitation assay (CHIP) were used to verify the targeting relationship between PPAR and SFRP5. The expression of tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and interleukin-6 (IL-6), which are indicators for the activation of Kupffer cells, were determined by enzyme linked immunosorbent assay (ELISA) after co-cultivation of L02 hepatocytes and Kupffer macrophages, as well as the exogenous regulation of SNO, PPARγ, and SFRP5 in hepatic L02 cells.

Results: The NAFL and NASH mouse models were successfully constructed, and the level of PPARγ SNO in the NAFL model was significantly lower than the NASH model (P<0.05). The level of PPARγ was significantly downregulated after increasing the SNO of L02 cells, respectively (P<0.05). Nubiscan software and CHIP confirmed that PPARγ could bind to the promoter region of SFRP5 (P<0.05). Overexpression of PPARγ and SFRP5 could significantly downregulate the expression of TNFα, IL-1β, and IL-6 (P<0.05) correspondingly, while increasing the SNO level of L02 cells could restore the expression levels of TNFα, IL-1β, and IL-6.

Conclusions: SNO promoted the activation of macrophage Kupffer cells by inhibiting the PPARγ/SFRP5 pathway in L02 hepatocytes, thereby promoting the conversion of NAFL into NASH.
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http://dx.doi.org/10.21037/atm-21-1070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106108PMC
April 2021

Medical Cloud Computing Data Processing to Optimize the Effect of Drugs.

J Healthc Eng 2021 19;2021:5560691. Epub 2021 Mar 19.

School of Nursing and Health, Henan University, Kaifeng 475001, China.

In recent years, cloud computing technology is maturing in the process of growing. Hadoop originated from Apache Nutch and is an open-source cloud computing platform. Moreover, the platform is characterized by large scale, virtualization, strong stability, strong versatility, and support for scalability. It is necessary and far-reaching, based on the characteristics of unstructured medical images, to combine content-based medical image retrieval with the Hadoop cloud platform to conduct research. This study combines the impact mechanism of senile dementia vascular endothelial cells with cloud computing to construct a corresponding data retrieval platform of the cloud computing image set. Moreover, this study uses Hadoop's core framework distributed file system HDFS to upload images, store the images in the HDFS and image feature vectors in HBase, and use MapReduce programming mode to perform parallel retrieval, and each of the nodes cooperates with each other. The results show that the proposed method has certain effects and can be applied to medical research.
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http://dx.doi.org/10.1155/2021/5560691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007357PMC
March 2021

Extract of inhibits lipid accumulation and ameliorates HFD-induced obesity in mice through regulating adipose differentiation by decreasing PPARγ and CEBP/α expression.

Food Nutr Res 2021 1;65. Epub 2021 Mar 1.

Tomas Lindahl Nobel Laureate Laboratory, Precision Medicine Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong, China.

Background: Obesity is a principal risk factor for the development of type 2 diabetes and cardiovascular diseases. Natural plants and/or foods play an important role in the management of obesity. (AAL) is a kind of potherb popular among Asian populations, and it is also consumed as a food ingredient and traditional herbal medicine.

Objective: We investigated the effects of water extract from AAL on high-fat-diet (HFD)-induced obese mice and 3T3-L1 adipocytes to develop a new functional food material.

Design: Nine-week-old male mice were randomly divided into control (chow diet, = 6) and HFD ( = 30) group. From 12-weeks onward, mice in the HFD group were further separated into model (saline, 6 mL/kg), simvastatin (0.11 mg/mL, 6 mL/kg), and AAL treatment (low, middle, and high dosage: 300, 600, and 900 mg/kg) group, with 6 animals per group, while mice in the control group were treated with saline (6 mL/kg). Food intake, body/fat weight, liver/kidney indexes, and lipid profiles were determined. Tissues were fixed with formalin for pathological examination. Western blotting and PCR were performed to evaluate the protein and mRNA expression in 3T3-L1 adipocytes. Oil Red O staining was used to determine lipid accumulation.

Results: AAL administration significantly suppressed body weight gain, and reduced fat pad weight and Lee's index in obese mice, but had no effect on liver/kidney index. AAL also reduced serum cholesterol, triglyceride, and LDL-C and increased HDL-C levels. Histological analysis revealed that AAL significantly ameliorated lipid accumulation in the liver and subcutaneous adipose tissue. , Oil Red O staining showed that AAL inhibited adipose differentiation by down-regulating the gene and protein expression of PPARγ and C/EBPα. AAL also reversed HFD-induced intestinal dysbacteriosis.

Conclusion: AAL water-soluble extract has a significant anti-adipogenic effect in the HFD-induced obese mice model.
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http://dx.doi.org/10.29219/fnr.v65.424DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7955518PMC
March 2021

Correction to: The early warning research on nursing care of stroke patients with intelligent wearable devices under COVID-19.

Pers Ubiquitous Comput 2021 Mar 16. Epub 2021 Mar 16.

College of Nursing and Health, Henan University, Kaifeng, 475001 China.

[This corrects the article DOI: 10.1007/s00779-021-01520-9.].
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http://dx.doi.org/10.1007/s00779-021-01537-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962427PMC
March 2021

Characteristics of chemical profile, sources and PAH toxicity of PM in beijing in autumn-winter transit season with regard to domestic heating, pollution control measures and meteorology.

Chemosphere 2021 Aug 1;276:130143. Epub 2021 Mar 1.

Joint Mass Spectrometry Center, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Neuherberg, Germany.

Several air pollution episodes occurred in Beijing before and after the 2014 Asia-Pacific Economic Cooperation (APEC) summit, during which air-pollution control measures were implemented. Within this autumn-winter transit season, domestic heating started. Such interesting period merits comprehensive chemical characterization, particularly the organic species, to look into the influence of additional heating sources and the control measures on air pollution. Therefore, this study performed daily and 6h time resolved PM sampling from the 24th October to 7th December, 2014, followed by comprehensive chemical analyses including water-soluble ions, elements and organic source-markers. Apparent alterations of chemical profiles were observed with the initiation of domestic heating. Through positive matrix factorization (PMF) source apportionment modeling, six PM sources including secondary inorganic aerosol (SIA), traffic emission, coal combustion, industry emission, biomass burning and dust were separated and identified. Coal combustion was successfully distinguished from traffic emission by hopane diagnostic ratio. The result of this study reveals a gradual shift of dominating sources for PM pollution episodes from SIA to primary sources after starting heating. BaP toxicity from coal combustion increased on average by several to dozens of times in the heating period, causing both long-term and short-term health risk. Air mass trajectory analysis highlights the regional influence of the industry emissions from the area south to Beijing. Control measures taken during APEC were found to be effective for reducing industry source, but less effective in reducing the overall PM level. These results provide implications for policy making regarding appropriate air pollution control measures.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130143DOI Listing
August 2021

The early warning research on nursing care of stroke patients with intelligent wearable devices under COVID-19.

Pers Ubiquitous Comput 2021 Jan 26:1-13. Epub 2021 Jan 26.

College of Nursing and Health, Henan University, Kaifeng, 475001 China.

Stroke patients under the background of the new crown epidemic need to be home-based care. However, traditional nursing methods cannot take care of the patients' lives in all aspects. Based on this, based on machine learning algorithms, our work combines regression models and SVM to build a smart wearable device system and builds a system prediction module to predict patient care needs. The node is used to collect human body motion and physiological parameter information and transmit data wirelessly. The software is used to quickly process and analyze the various motion and physiological parameters of the patient and save the analysis and processing structure in the database. By comparing the results of nursing intervention experiments, we can see that the smart wearable device designed in this paper has a certain effect in stroke care.
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http://dx.doi.org/10.1007/s00779-021-01520-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7837337PMC
January 2021

Spectrum analysis of inborn errors of metabolism for expanded newborn screening in a northwestern Chinese population.

Sci Rep 2021 Jan 29;11(1):2699. Epub 2021 Jan 29.

Center of Neonatal Disease Screening, Department of Clinical Genetics, Northwest Women's and Children's Hospital, 1616 Yanxiang Road, Xi'an, Shaanxi Province, China.

Expanded newborn screening facilitates early identification and intervention of patients with inborn errors of metabolism (IEMs), There is a lack of disease spectrum data for many areas in China. To determine the disease spectrum and genetic characteristics of IEMs in Xi'an city of Shaanxi province in northwest China, 146152 newborns were screening by MSMS from January 2014 to December 2019 and 61 patients were referred to genetic analysis by next generation sequencing (NGS) and validated by Sanger sequencing. Seventy-five newborns and two mothers were diagnosed with IEMs, with an overall incidence of 1:1898 (1:1949 without mothers). There were 35 newborns with amino acidemias (45.45%, 1:4176), 28 newborns with organic acidurias (36.36%, 1:5220), and 12 newborns and two mothers with FAO disorders (18.18%; 1:10439 or 1:12179 without mothers). Phenylketonuria and methylmalonic acidemia were the two most common disorders, accounting for 65.33% (49/75) of all confirmed newborn. Some hotspot mutations were observed for several IEMs, including PAH gene c.728G>A for phenylketonuria; MMACHC gene c.609G>A and c.567dupT, MMUT gene c.323G>A for methylmalonic acidemia and SLC25A13 gene c.852_855del for citrin deficiency. Our study provides effective clinical guidance for the popularization and application of expanded newborn screening, genetic screening, and genetic counseling of IEMs in this region.
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http://dx.doi.org/10.1038/s41598-021-81897-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846761PMC
January 2021

Dysbiosis of urine microbiota in obstructive urinary retention patients revealed by next-generation sequencing.

Ann Clin Microbiol Antimicrob 2021 Jan 6;20(1). Epub 2021 Jan 6.

Department of Ultrasonography, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.

Background: Urinary retention (UR) is a common urinary system disease can be caused by urinary tract obstruction with numerous reasons, however, the role of urine microbes in these disorders is still poorly understood. The aim of this study was to identify the urine microbial features of two common types of obstructive UR, caused by urinary stones or urinary tract tumors, with comparison to healthy controls.

Methods: Urine samples were collected from a cohort of 32 individuals with stone UR, 25 subjects with tumor UR and 25 healthy controls. The urine microbiome of all samples was analyzed using high-throughput 16S rRNA (16S ribosomal RNA) gene sequencing.

Results: We observed dramatically increased urine microbial richness and diversity in both obstructive UR groups compared to healthy controls. Despite different origins of UR, bacteria such as Pseudomonas, Acinetobacter and Sphingomonas were enriched, while Lactobacillus, Streptococcus, Gardnerella, Prevotella and Atopobium were decreased in both UR groups in comparison with healthy controls, exhibited an approximate urine microbial community and functional characteristics of two types of obstructive UR. Furthermore, disease classifiers were constructed using specific enriched genera in UR, which can distinguish stone UR or tumor UR patients from healthy controls with an accuracy of 92.29% and 97.96%, respectively.

Conclusion: We presented comprehensive microbial landscapes of two common types of obstructive urinary retention and demonstrated that urine microbial features of these patients are significantly different from that of healthy people. The urine microbial signatures would shed light on the pathogenesis of these types of urinary retention and might be used as potential classification tools in the future.
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http://dx.doi.org/10.1186/s12941-020-00408-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789751PMC
January 2021

Distinct genetic patterns of shared and unique genes across four neurodevelopmental disorders.

Am J Med Genet B Neuropsychiatr Genet 2021 01 15;186(1):3-15. Epub 2020 Sep 15.

Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, China.

Neurodevelopmental disorders, including autism spectrum disorder (ASD), intellectual disability (ID), developmental disorders (DD) and epileptic encephalopathy (EE), have a strong clinical comorbidity, which indicates a common genetic etiology across various disorders. However, the underlying genetic mechanisms of comorbidity and specificity remain unknown across neurodevelopmental disorders. Based on de novo mutations, we compared systematically the functional characteristics between shared and unique genes under these disorders, as well as the spatiotemporal trajectory of development in brain and common molecular pathways of all shared genes. We observed that shared genes present more constrained against functional rare genetic variation, and harbor more pathogenic rare variants than do unique genes in each disorder. Furthermore, 71 shared genes formed two clusters related to synaptic transmission, transcription regulation and chromatin regulator. Particularly, we also found that two core genes STXBP1 and SCN2A, that were shared by the four neurodevelopmental disorders showed prominent pleiotropy. Our findings shed light on the shared and specific patterns across neurodevelopmental disorders and will enable us to further comprehend the etiology and provide valuable information for the diagnosis of neurodevelopmental disorders.
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http://dx.doi.org/10.1002/ajmg.b.32821DOI Listing
January 2021

Degradome, small RNAs and transcriptome sequencing of a high-nicotine cultivated tobacco uncovers miRNA's function in nicotine biosynthesis.

Sci Rep 2020 07 16;10(1):11751. Epub 2020 Jul 16.

China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China.

Tobacco (Nicotiana tabacum) is considered as the model plant for alkaloid research, of which nicotine accounts for 90%. Many nicotine biosynthetic genes have been identified and were known to be regulated by jasmonate-responsive transcription factors. As an important regulator in plant physiological processes, whether small RNAs are involved in nicotine biosynthesis is largely unknown. Here, we combine transcriptome, small RNAs and degradome analysis of two native tobacco germplasms YJ1 and ZY100 to investigate small RNA's function. YJ1 leaves accumulate twofold higher nicotine than ZY100. Transcriptome analysis revealed 3,865 genes which were differently expressed in leaf and root of two germplasms, including some known nicotine and jasmonate pathway genes. By small RNA sequencing, 193 miRNAs were identified to be differentially expressed between YJ1 and ZY100. Using in silico and degradome sequencing approaches, six nicotine biosynthetic genes and seven jasmonate pathway genes were predicted to be targeted by 77 miRNA loci. Three pairs among them were validated by transient expression in vivo. Combined analysis of degradome and transcriptome datasets revealed 51 novel miRNA-mRNA interactions that may regulate nicotine biosynthesis. The comprehensive analysis of our study may provide new insights into the regulatory network of nicotine biosynthesis.
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http://dx.doi.org/10.1038/s41598-020-68691-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7366715PMC
July 2020

In situ Metabolite Mass Spectrometry Imaging: New Insights into the Adrenal Gland.

Horm Metab Res 2020 Jun 29;52(6):435-447. Epub 2020 Apr 29.

Research Unit Analytical Pathology, German Research Center for Environmental Health, Helmholtz Zentrum München, München, Germany.

The adrenal gland integrates catecholamine-producing neuroendocrine cells and steroid-producing cells with mesenchymal origin in a structured manner under one capsule and is a key regulator for vital bioactivity. In addition to adrenal-specific disease, dysregulation of adrenal hormones is associated with systemic effects, leading to undesirable metabolic and cardiovascular consequences. Mass spectrometry imaging (MSI) technique can simultaneously measure a broad range of biomolecules, including metabolites and hormones, which has enabled the study of tissue metabolic and hormone alterations in adrenal and adrenal-related diseases. Furthermore, this technique coupled with labeled immunohistochemistry staining has enabled the study of the pathophysiological adaptation of the adrenal gland under normal and abnormal conditions at different molecular levels. This review discusses the recent applications of in situ MSI in the adrenal gland. For example, the combination of formalin-fixed paraffin-embedded tissue microarray and MSI to tissues from patient cohorts has facilitated the discovery of clinically relevant prognostic biomolecules and generated promising hypotheses for new sights into physiology and pathophysiology of adrenal gland. MSI also has enabled the discovery of clinically significant tissue molecular (i. e., biomarker) and pathway changes in adrenal disease, particularly in adrenal tumors. In addition, MSI has advanced the ability to optimally identify and detect adrenal gland specific molecules. Thus, as a novel analytical methodology, MSI has provided unprecedented capabilities for in situ tissue study.
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http://dx.doi.org/10.1055/a-1129-6947DOI Listing
June 2020

Circular RNA sequencing indicates circ-IQGAP2 and circ-ZC3H6 as noninvasive biomarkers of primary Sjögren's syndrome.

Rheumatology (Oxford) 2020 09;59(9):2603-2615

Department of Rheumatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.

Objectives: This study aims to characterize the expression profiles of circRNAs in primary Sjogren's Syndrome (pSS) and examine the potential of noninvasive circular RNAs (circRNAs) as biomarkers of pSS.

Methods: We performed RNA sequencing of minor salivary gland (MSG) biopsies from four pSS and four non-pSS individuals (subjects undergoing MSG biopsies but not meeting 2012 or 2016 ACR classification criteria for SS). Differentially expressed circRNAs were identified by DESeq2, and confirmed by quantitative real-time PCR in the MSGs as well as in plasma exosomes in 37 pSS and 14 non-pSS subjects. Discriminatory capacity testing using receiver operating characteristic analysis was used to evaluate the performance of circRNAs as diagnostic biomarkers for pSS.

Results: Circ-IQGAP2 and circ-ZC3H6 had significantly upregulated expression in the MSGs of pSS patients, and this elevated expression was confirmed by quantitative real-time PCR of plasma exosome RNA. The expression of these circRNAs also showed significant correlation with both clinical features, serum IgG level and MSG focus scores. Receiver operating characteristic analysis showed that the indices comprised of both the two circRNAs and clinical features were better able to distinguish pSS from non-pSS subjects with high mean areas under the curve of 0.93 in the MSGs and 0.92 in the plasma exosomes.

Conclusion: This study indicated the potential roles of circ-IQGAP2 and circ-ZC3H6 as noninvasive biomarkers for the diagnosis of pSS.
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http://dx.doi.org/10.1093/rheumatology/keaa163DOI Listing
September 2020

Comparative Transcriptome Analysis Reveals the Potential Mechanism of Abortion in Tobacco -Cytoplasmic Male Sterility.

Int J Mol Sci 2020 Apr 1;21(7). Epub 2020 Apr 1.

Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China.

-CMS (cytoplasmic male sterility) is the only male sterile system in tobacco breeding, but the mechanism of abortion is unclear. Cytological characteristics show that abortion in the -CMS line msZY occurs before the differentiation of sporogenous cells. In this study, a comparative transcriptomic analysis was conducted on flower buds at the abortion stage of msZY and its male fertile control ZY. A total of 462 differentially expressed genes were identified in msZY and ZY, which were enriched via protein processing in the endoplasmic reticulum (ER), oxidative phosphorylation, photosynthesis, and circadian rhythm-plant by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Most genes were downregulated in the ER stress pathway, heat-shock protein family, F1F0-ATPase encoding by the mitochondrial genome, and differentiation of stamens. Genes in the programmed cell death (PCD) pathway were upregulated in msZY. The transcriptome results were consistent with those of qRT-PCR. Ultrastructural and physiological analyses indicted active vacuole PCD and low ATP content in msZY young flower buds. We speculated that PCD and a deficiency in ATP synthesis are essential for the abortion of -CMS. This study reveals the potential mechanism of abortion of tobacco -CMS.
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http://dx.doi.org/10.3390/ijms21072445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178165PMC
April 2020

Isolation, Molecular Characterization and Antibiotic Susceptibility Pattern of from Aquatic Products in the Southern Fujian Coast, China.

J Microbiol Biotechnol 2020 Jun;30(6):856-867

Zhangzhou Center for Disease Control and Prevention, Zhangzhou 363000, P.R. China.

is a major gastroenteritis-causing pathogen in many Asian countries. Antimicrobial resistance in has been recognized as a critical threat to food safety. In this study, we determined the prevalence and incidence of antimicrobial resistance in in the southern Fujian coast, China. A total of 62 isolates were confirmed in retail aquatic products from June to October of 2018. The serotype O3:K6 strains, the virulence genes and , antibiotic susceptibility and molecular typing were investigated. Then plasmid profiling analysis and curing experiment were performed for multidrug-resistant strains. The results showed that the total occurrence of was 31% out of 200 samples. Five strains (8.1%) out of 62 isolates were identified as the O3:K6 pandemic clone. A large majority of isolates exhibited higher resistance to penicillin (77.4%), oxacillin (71%), ampicillin (66.1%) and vancomycin (59.7%). Seventy-one percent (44/62) of the isolates exhibited multiple antimicrobial resistance. All 62 isolates were grouped into 7 clusters by randomly amplified polymorphic DNA, and most of the isolates (80.6%) were distributed within cluster A. Plasmids were detected in approximately 75% of the isolates, and seven different profiles were observed. Seventy-six percent (25/33) of the isolates carrying the plasmids were eliminated by 0.006% SDS incubated at 42°C, a sublethal condition. The occurrence of multidrug-resistant strains could be an indication of the excessive use of antibiotics in aquaculture farming. The rational use of antimicrobial agents and the surveillance of antibiotic administration may reduce the acquisition of resistance by microorganisms in aquatic ecosystems.
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http://dx.doi.org/10.4014/jmb.2001.01005DOI Listing
June 2020

Diagnosing chronic atrophic gastritis by gastroscopy using artificial intelligence.

Dig Liver Dis 2020 05 13;52(5):566-572. Epub 2020 Feb 13.

School of Computer Science and Technology, Xidian University, Xi'an, China.

Background: The sensitivity of endoscopy in diagnosing chronic atrophic gastritis is only 42%, and multipoint biopsy, despite being more accurate, is not always available.

Aims: This study aimed to construct a convolutional neural network to improve the diagnostic rate of chronic atrophic gastritis.

Methods: We collected 5470 images of the gastric antrums of 1699 patients and labeled them with their pathological findings. Of these, 3042 images depicted atrophic gastritis and 2428 did not. We designed and trained a convolutional neural network-chronic atrophic gastritis model to diagnose atrophic gastritis accurately, verified by five-fold cross-validation. Moreover, the diagnoses of the deep learning model were compared with those of three experts.

Results: The diagnostic accuracy, sensitivity, and specificity of the convolutional neural network-chronic atrophic gastritis model in diagnosing atrophic gastritis were 0.942, 0.945, and 0.940, respectively, which were higher than those of the experts. The detection rates of mild, moderate, and severe atrophic gastritis were 93%, 95%, and 99%, respectively.

Conclusion: Chronic atrophic gastritis could be diagnosed by gastroscopic images using the convolutional neural network-chronic atrophic gastritis model. This may greatly reduce the burden on endoscopy physicians, simplify diagnostic routines, and reduce costs for doctors and patients.
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http://dx.doi.org/10.1016/j.dld.2019.12.146DOI Listing
May 2020

Cyclic glycine-proline normalizes systolic blood pressure in high-fat diet-induced obese male rats.

Nutr Metab Cardiovasc Dis 2020 02 25;30(2):339-346. Epub 2019 Sep 25.

The Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1142, New Zealand; Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1142, New Zealand; Brain Research New Zealand, A Centre of Research Excellence, New Zealand. Electronic address:

Background And Aims: Insulin-like growth factor (IGF)-1 deficiency is associated with a range of metabolic disorders. Cyclic glycine-proline (cGP) is a natural nutrient and regulates the amount of active IGF-1 in plasma. Plasma cGP decreases in hypertensive women whereas increases in obese women, suggesting its involvement in cardio-metabolic function. We therefore examined the effects of cGP on metabolic profiles and blood pressure in high-fat diet (HFD)-induced obese male rats.

Methods: Male rats were fed either a HFD or a standard chow diet (STD) ad-libitum from 3 to 15 weeks of age. Rats were administered either saline or cGP from 11 to 15 weeks of age. At 14 weeks of age, systolic-blood pressure (SBP) was measured by tail-cuff plethysmography and body composition quantified by DEXA. Blood and retroperitoneal fat tissues were collected. Plasma concentrations of insulin, IGF-1, IGF binding protein (IGFBP)-3 and cGP were evaluated using ELISA and HPLC-MS respectively.

Results: Compared to STD, HFD feeding increased SBP, total fat mass and fat/lean ratio, retroperitoneal fat weight, fasting plasma insulin and cGP concentrations whereas decreased plasma IGF-1 and IGFBP-3 concentrations. Administration of cGP reduced SBP and retroperitoneal fat weight, but had no effect on body composition and plasma insulin concentrations.

Conclusion: HFD-associated decreases in IGFBP-3 and increases in cGP represent an autocrine response to normalize IGF-1 function through improving the amount of bioavailable IGF-1 in the circulation of obese male rats. The beneficial effects of cGP on SBP and retroperitoneal fat mass may suggest a therapeutic potential for cGP in HFD-associated cardio-metabolic complications.
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http://dx.doi.org/10.1016/j.numecd.2019.09.016DOI Listing
February 2020

Myrothecine A modulates the proliferation of HCC cells and the maturation of dendritic cells through downregulating miR-221.

Int Immunopharmacol 2019 Oct 31;75:105783. Epub 2019 Jul 31.

Institute of Hand Surgery, Ruihua Affiliated Hospital of Soochow University, Suzhou 215007, China.

Myrothecine A, characterized from the extracts of myrothecium roridum strain IFB-E012, isolated as endophytic fungi found in the traditional Chinese medicinal plant Artemisia annua. Here we investigated its roles on anti-tumor and immune regulation in vitro. Dendritic cells (DCs) are the most potent antigen presenting cells in immune responses. Recent studies have indicated that miRNAs are indispensable in regulating the development, differentiation, maturation and function of DC. MiR-221, acted as an oncogene, is an important regulator in cancer development by binding to 3' untranslated regions (3' UTR) of target mRNA. Here, we investigated whether myrothecine A could inhibit cell proliferation in hepatocellular carcinoma (HCC) cell line SMMC-7721 by regulating miR-221. The HCC cells were treated with myrothecine A at different concentration, and the cell growth ability was measured by MTT assay. Then we observed whether myrothecine A could affect the maturation of DC by regulating miR-221. The HCC cell line was co-cultured with immature DC from mice bone marrow, and the levels of CD86 and CD40 was detected by FCM. Our results showed that myrothecine A could rescue miR-221-induced cell proliferation and influence the protein level of p27 by inhibiting the expression of miR-221. In addition, myrothecine A could enhance the expression of CD86 and CD40 by reversing the function of miR-221. Therefore, myrothecine A may be acted as an anti-tumor drug to promote the maturation of DC in the microenvironment of hepatocellular carcinoma.
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http://dx.doi.org/10.1016/j.intimp.2019.105783DOI Listing
October 2019

Correction: Nonrandom occurrence of multiple de novo coding variants in a proband indicates the existence of an oligogenic model in autism.

Genet Med 2019 11;21(11):2662-2663

Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, China.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41436-019-0629-4DOI Listing
November 2019

Nonrandom occurrence of multiple de novo coding variants in a proband indicates the existence of an oligogenic model in autism.

Genet Med 2020 01 23;22(1):170-180. Epub 2019 Jul 23.

Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, China.

Purpose: Elucidating the genetic architecture underlying autism spectrum disorder (ASD) will aid in the understanding of its genetic etiology and clinical diagnosis.

Methods: A comprehensive set of coding de novo variants (DNVs) from 4504 trios with ASD and 3012 control/sibling trios from several large-scale sequencing studies were collected and combined. Multiple in-depth analyses including DNVs burden, clinical phenotypes, and functional networks underlying the combined data set were used to evaluate the nonrandom occurrence of multiple extreme DNVs (loss-of-function and damaging missense variants) in the same patients.

Results: We observed a significant excess of multiple extreme DNVs among patients with ASD compared with controls. Meanwhile, patients with ASD carrying 2+ extreme DNVs had significantly lower IQs than patients carrying 0 or 1 DNV. Moreover, much closer functional connectivity than expected was observed among 2 or more genes with extreme DNVs from the same individuals. In particular, we identified 56 key genes as more confident ASD genes compared with other known ASD genes. In addition, we detected 23 new ASD candidate genes with recurrent DNVs, including VIP, ZWILCH, MSL2, LRRC4, and CAPRIN1.

Conclusions: Our findings present compelling statistical evidence supporting an oligogenic model and provide new insights into the genetic architecture of ASD.
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http://dx.doi.org/10.1038/s41436-019-0610-2DOI Listing
January 2020

Alterations to the Gut Microbiota and Their Correlation With Inflammatory Factors in Chronic Kidney Disease.

Front Cell Infect Microbiol 2019 12;9:206. Epub 2019 Jun 12.

People's Hospital Affiliated to Shanxi Medical University, Taiyuan, China.

Alterations to the gut microbiota have been previously suggested to be tightly linked to chronic systemic inflammation, which is a major contributing factor to complications and disease progression in chronic kidney disease (CKD). Nevertheless, the effect of gut dysbiosis on the pathogenesis and/or production of inflammatory factors in CKD has not been extensively studied to date. In the present study, we conducted 16S ribosomal DNA pyrosequencing using fecal microbiota samples and analyzed the production of serum inflammatory factors in 50 patients with CKD and 22 healthy control (HC) subjects. The results revealed that compared to the HC subjects, patients with CKD exhibited a significant reduction in the richness and structure of their fecal microbiota. At the phylum level, compared to the HC group, patients with CKD also presented reduced abundance of Actinobacteria but increased abundance of Verrucomicrobia. Moreover, the genera , and were enriched in the fecal samples of patients with CKD, while and were enriched in those of the HC subjects. The abundance of in the CKD group was significantly lower than that in the HC group (3.08 vs. 0.67%); this decrease in the abundance of , an important probiotic, in patients with CKD is a striking discovery as it has not been previously reported. Finally, we analyzed whether these changes to the fecal microbiota correlated with CKD clinical characteristics and/or the production of known inflammatory factors. Altered levels of the microbiota genera , and were shown to be correlated with CKD disease-severity indicators, including the estimated glomerular filtration rate. Most notably, was significantly negatively correlated with the production of interleukin-10. The results of the present study suggest that microbiota dysbiosis may promote chronic systemic inflammation in CKD. Furthermore, they support that modifying the gut microbiota, especially , may be a promising potential therapeutic strategy to attenuate the progression of, and/or systemic inflammation in, CKD.
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http://dx.doi.org/10.3389/fcimb.2019.00206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581668PMC
February 2020

MiR-221 Promotes Hepatocellular Carcinoma Cells Migration via Targeting PHF2.

Biomed Res Int 2019 12;2019:4371405. Epub 2019 May 12.

Institute of Hand Surgery, Ruihua Affiliated Hospital of Soochow University, Suzhou 215007, China.

MicroRNAs (MiRNAs), which regulate the gene expression leading to translational inhibition or mRNA degradation, are involved in carcinogenesis and tumor progression. Previous studies have demonstrated that miR-221 was one of the most consistent overexpressed miRNAs in several types of cancer. However, the role of miR-221 in human liver cancer progression is not yet fully elucidated. Levels of miR-221 and plant homeodomain finger 2 (PHF2) expressions in human hepatocellular carcinoma (HCC) tissues and cell lines were detected using western blotting and quantitative real-time PCR (qRT-PCR). Cell migration was studied using the transwell assays. A dual-luciferase reporter system was used to validate the target gene of miR-221. The results indicated that miR-221 promoted HCC cell migration. By performing subsequent systematic bioinformatic analyses, we found PHF2 was the target gene of miR-221 and the direct binding relationship was further validated by dual-luciferase reporter assay. In addition, lower expression of PHF2 promoted HCC cell migration and linked to worse overall survival in HCC patients. Finally, the negative correlation between miR-221 and PHF2 expression levels in HCC specimens was further confirmed. Taken together, our findings implied that miR-221 could be a potential candidate for the therapeutics of HCC metastasis.
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http://dx.doi.org/10.1155/2019/4371405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6535842PMC
December 2019

Cyclic glycine-proline administration normalizes high-fat diet-induced synaptophysin expression in obese rats.

Neuropeptides 2019 Aug 22;76:101935. Epub 2019 May 22.

The Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand; Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1124, New Zealand; Brain Research New Zealand, A Centre of Research Excellence, New Zealand. Electronic address:

Childhood metabolic disorders are associated with insulin-like growth factor (IGF)-1 deficiency, which can adversely affect brain development and function. As a neuropeptide, cyclic glycine-proline (cGP) improves IGF-1 function in brain and regulates IGF-1 bioavailability in plasma. Whether such a regulatory process mediates the neurotrophic effects of cGP remains unknown. This study examined the effects cGP treatment on synaptic expression and their association with IGF-1, IGF binding protein (IGFBP)-2 and cGP concentrations in the brain of rats with high fat diet (HFD)-induced obesity. Male rats received either a HFD or a standard chow diet (STD) from weaning and were then treated with either saline or cGP from 11 to 15 weeks of age. The concentrations of cGP, IGF-1 and IGFBP-2 were measured in the brain tissues using ELISA and HPLC-MS. The expressions of synaptic markers were evaluated in the hippocampus, hypothalamus and striatum using immunohistochemical staining. Compared to the STD group, IGF-1 and IGFBP-2, but not cGP concentrations, were lower in the HFD groups. The expression of hippocampal synaptophysin, glutamate receptor-1, GFAP and striatal tyrosine-hydroxylase were also reduced in the HFD groups. While treatment did not alter tissue IGF-1, cGP administration that increased the concentration of cGP in brain tissues, normalized the expression of synaptophysin, GFAP and tyrosine-hydroxylase, but not glutamate receptor-1. IGF-1 concentration in brain tissues correlated with the expression of all synaptic markers. HFD feeding reduced synaptic expression and tissue IGF-1 in brains which were closely associated, thus suggesting IGF-1 in the brain is largely bioavailable. Without increasing IGF-1 in the brain, administration of cGP normalized synaptic expression, possibly be mediated through increasing bioavailable IGF-1, but further studies are required to confirm this.
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http://dx.doi.org/10.1016/j.npep.2019.05.006DOI Listing
August 2019

L-carnitine ameliorated weight loss in fasting therapy: A propensity score-matched study.

Complement Ther Med 2019 Jun 4;44:162-165. Epub 2019 Apr 4.

Department of Traditional Chinese Medicine, the Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, China. Electronic address:

l-carnitine infusion has been proven to reduce fasting-induced fatigue and hunger in patients with metabolic syndrome in our former study. However, the association between l-carnitine and clinical outcomes of fasting therapy is yet to be investigated. In this study, data from 192 patients who finished fasting therapy from September 2008 to July 2018 were reviewed, among which 142 patients received l-carnitine infusion in fasting regimen. Propensity matching was used to overcome retrospective bias. Patients' anthropometric measurements and metabolic markers were evaluated. After propensity matching, 40 patients were included in each group. Weight (-4.05 ± 1.65 kg vs -3.25 ± 1.68 kg, P = 0.031) and BMI (-1.51±0.61 kg/m vs -1.20 ± 0.62 kg/m, P = 0.036) decreased in both groups, but significantly more in l-carnitine group, while diastolic blood pressure (-1.67±9.82 mmHg vs -6.21±8.83 mmHg, P = 0.043) and triglycerides (-0.18±0.63 mmol/L vs -1.05±1.70 mmol/L, P = 0.007) decreased significantly more in non-l-carnitine group compared between groups, blood glucose did not differ significantly between groups. l-carnitine can boost the positive effects of fasting therapy on weight loss and maintain the stability of blood pressure.
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http://dx.doi.org/10.1016/j.ctim.2019.03.020DOI Listing
June 2019

Elevated / Expression During the Disease Process of Primary Sjögren's Syndrome.

Front Immunol 2019 24;10:795. Epub 2019 Apr 24.

Rheumatology Department, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.

Primary Sjögren's syndrome (pSS) is a common chronic autoimmune disease characterized by a high prevalence of autoantibodies and lymphocyte-mediated exocrine gland damage. To enhance our understanding of the mechanisms underlying the progression of the disease and to discover potential biomarkers for the early diagnosis of pSS, we applied RNA sequencing to compare the gene expression patterns in minor salivary glands between pSS patients and non-pSS. A total of 293 differentially expressed genes (DEGs) were detected in pSS vs. non-pSS (FDR < 0.05, fold changes > 2). Of these DEGs, 285 (97.26%) were up-regulated, with most being involved in immune system activation, especially in the formation of the immunological synapse. Significantly elevated / expression in the salivary gland was found to be related to anti-Sjögren's syndrome-related antigen A (SSA) antibody and IgG levels in pSS patients, which was further confirmed in a larger cohort. Up-regulated gene expression showed strong discriminatory accuracy in identifying pSS with area under the curve of 0.98 using receiver operating characteristic curve analysis. In conclusion, gene expression changes in pSS include strong markers of immunological activation and have good discriminatory power in identifying patients with pSS.
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http://dx.doi.org/10.3389/fimmu.2019.00795DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6491632PMC
October 2020

NtMYB4 and NtCHS1 Are Critical Factors in the Regulation of Flavonoid Biosynthesis and Are Involved in Salinity Responsiveness.

Front Plant Sci 2019 21;10:178. Epub 2019 Feb 21.

Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China.

High levels of salinity induce serious oxidative damage in plants. Flavonoids, as antioxidants, have important roles in reactive oxygen species (ROS) scavenging. In the present study, the tobacco R2R3 MYB type repressor, NtMYB4, was isolated and characterized. The expression of was suppressed by salinity. Overexpression of reduced the salt tolerance in transgenic tobacco plants. NtMYB4 repressed the promoter activity of and negatively regulated its expression. Rutin accumulation was significantly decreased in overexpressing transgenic plants and RNAi silenced transgenic plants. Moreover, high HO and contents were detected in both types of rutin-reduced transgenic plants under high salt stress. In addition, exogenous rutin supplementation effectively scavenged ROS (HO and ) and improved the salt tolerance of the rutin-reduced transgenic plants. In contrast, overexpressing plants had increased rutin accumulation, lower HO and contents, and higher tolerance to salinity. These results suggested that tobacco NtMYB4 acts as a salinity response repressor and negatively regulates expression, which results in the reduced flavonoid accumulation and weakened ROS-scavenging ability under salt stress.
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http://dx.doi.org/10.3389/fpls.2019.00178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6393349PMC
February 2019

Characterization of genes specific to sua-CMS in Nicotiana tabacum.

Plant Cell Rep 2018 Sep 29;37(9):1245-1255. Epub 2018 Jun 29.

Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.

Key Message: Six unique ORFs were characterized in tobacco plants with sua-CMS sterile cytoplasm, identifying the mtDNA basis for pollen sterility. sua-CMS (cytoplasmic male sterility), the most widely used sterile system in tobacco hybrids, is the only CMS type identified as having no negative effects on agronomic or quality traits in tobacco (Nicotiana tabacum) and as being fully male sterile. CMS is often associated with alterations of mitochondrial DNA (mtDNA), including novel chimeric open reading frames (ORFs), which result from rearrangement and recombination. Here, we obtained 34 mitochondrial ORFs in the sua-CMS line msZhongyan100 (sZY) by BLAST analysis. When we amplified these mitochondrial ORFs in seven tobacco CMS lines including sua-, glu-, rep-, rus-, tab1-, tab2-, and tab3-CMS types and in fertile tobacco, we found that six ORFs-orf82, orf103, orf115, orf91, orf115, and orf100-were located in three small regions (m-sr) of the mitochondrial genome of sZY and were unique to the sua-CMS line. We further amplified the m-sr fragments in three different backcross populations of the seven types of CMS, three F1 hybrids with sua-CMS sterile cytoplasm, two sua-CMS lines, and 284 fertile tobacco accessions. The ORFs were specific to plants with the sua-CMS background. All six unique ORFs were chimeric and had no homology with the mitochondrial genomes of fertile tobacco. Transcript analysis revealed that the ORFs were highly expressed in the anthers and floral buds of sZY. These six ORFs were specific to sua-CMS and could be used as molecular markers to identify sua-CMS lines, which is useful for improving breeding for heterosis in tobacco.
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http://dx.doi.org/10.1007/s00299-018-2309-2DOI Listing
September 2018

Spatial and temporal variation of sources contributing to quasi-ultrafine particulate matter PM in Augsburg, Germany.

Sci Total Environ 2018 Aug 16;631-632:191-200. Epub 2018 Mar 16.

Joint Mass Spectrometry Center, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Neuherberg, Germany; Joint Mass Spectrometry Center, Chair of Analytical Chemistry, University of Rostock, Germany.

Objective: to study the sources contributing to quasi-ultrafine particle (UFP) organic carbon and the spatial temporal variability of the sources.

Method: 24h quasi-UFP (particulate matter <0.36μm in this study) was sampled at a reference site continuously and at one of 5 other sites (T1, T2, T3, T4 and B1) in parallel in Augsburg, Germany from April 11th, 2014 to February 22nd, 2015, attempting to conduct 2-week campaigns at each site in 3 different seasons. Positive matrix factorization (PMF) was applied to measured organic tracers for source apportionment analyses. Pearson correlation coefficient r and coefficient of divergence (COD) were calculated to investigate spatial temporal variation of source contributions.

Result: 5 sources were identified comprising biomass burning (BB), traffic emissions (Traffic), biogenic secondary organic aerosol (bioSOA), isoprene originated secondary organic aerosol (isoSOA) and biomass burning related secondary organic aerosol (bbSOA). In general, good temporal correlation and uniform distribution within the study area are found for bioSOA and bbSOA, probably resulting from regional formation/transport. Lower temporal correlation and spatial heterogeneity of isoSOA were found at the city background site with local influence from green space and less traffic impact. BB demonstrated very good temporal correlation, but higher contributions at sites influenced by local residential heating emissions were observed. Traffic showed the least seasonality and lower correlation over time among the sources. However, it demonstrated low spatial heterogeneity of absolute contribution, and only a few days of elevated contribution was found at T3 when wind came directly from the street nearby.

Conclusion: temporal correlation and spatial variability of sources contributing to the organic fraction of quasi-UFP vary among sites and source types and show source-specific characteristics. Therefore, caution should be taken when using one monitor site measurement to assess human exposure in health effect studies of quasi-UFP.
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http://dx.doi.org/10.1016/j.scitotenv.2018.03.041DOI Listing
August 2018

Optimization of novel monobactams with activity against carbapenem-resistant Enterobacteriaceae - Identification of LYS228.

Bioorg Med Chem Lett 2018 02 4;28(4):748-755. Epub 2018 Jan 4.

Novartis Institutes for BioMedical Research, Emeryville, CA, USA.

Metallo-β-lactamases (MBLs), such as New Delhi metallo-β-lactamase (NDM-1) have spread world-wide and present a serious threat. Expression of MBLs confers resistance in Gram-negative bacteria to all classes of β-lactam antibiotics, with the exception of monobactams, which are intrinsically stable to MBLs. However, existing first generation monobactam drugs like aztreonam have limited clinical utility against MBL-expressing strains because they are impacted by serine β-lactamases (SBLs), which are often co-expressed in clinical isolates. Here, we optimized novel monobactams for stability against SBLs, which led to the identification of LYS228 (compound 31). LYS228 is potent in the presence of all classes of β-lactamases and shows potent activity against carbapenem-resistant isolates of Enterobacteriaceae (CRE).
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http://dx.doi.org/10.1016/j.bmcl.2018.01.006DOI Listing
February 2018

Organic speciation of ambient quasi-ultrafine particulate matter (PM) in Augsburg, Germany: Seasonal variability and source apportionment.

Sci Total Environ 2018 Feb 7;615:828-837. Epub 2017 Oct 7.

Joint Mass Spectrometry Center, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, Neuherberg, Germany; Joint Mass Spectrometry Center, Chair of Analytical Chemistry, University of Rostock, Germany.

To investigate the organic composition and their sources of very fine atmospheric particulate matter (PM), size-segregated PM was sampled using rotating drum impactor (RDI) in series with a sequential filter sampler in Augsburg, Germany, from April 2014 to February 2015. Organic speciation analysis and organic carbon/elemental carbon (OC/EC) analysis was performed for the smallest size fraction PM (PM<360nm). Different OC fractions were determined by thermal optical EC/OC analyzer, and OC2, OC3 and OC4 refer to OC fractions that were derived at 280, 480 and 580°C, respectively. Positive matrix factorization (PMF) analysis was applied for source apportionment study. PMF resolved 5 sources including biogenic dominated secondary organic aerosol (bioSOA), isoprene dominated SOA (isoSOA), traffic, biomass burning (BB) and biomass burning originated SOA (bbSOA). On annual average, PMF results indicate the largest contribution of biogenic originated SOA (bioSOA plus isoSOA) to OC, followed by traffic and then BB related sources (BB plus bbSOA). Traffic was found to be associated with the smallest particles; whereas bioSOA and BB are associated with larger particles. Secondary organic marker compounds from biogenic precursors, OC2, OC3 and bioSOA, isoSOA source factors show summer maximum. Polycyclic aromatic hydrocarbons (PAHs), biomass burning markers, OC4 and BB, bbSOA source factors show winter maximum. Hopanes and the traffic source factor show little seasonal variation. Summer peaks of OC3 and OC2 are well modeled by PMF and are attributed mainly to biogenic SOA. OC4 was generally poorly modeled due to lack of characteristic low volatile markers. Summer maxima of biogenic SOA related compounds and source factors are positively correlated with temperature, global radiation, O concentration and mixing layer height (MLH). Winter maxima of BB related compounds and source factors are negatively correlated with temperature and MLH; whereas positively correlated with NO level.
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http://dx.doi.org/10.1016/j.scitotenv.2017.09.158DOI Listing
February 2018