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308 results on '"Li, Fei"'

2. The short-chain fatty acid propionate prevents ox-LDL-induced coronary microvascular dysfunction by alleviating endoplasmic reticulum stress in HCMECs.

Author

Hong, Dan, Tang, Wen, Li, Fei, Liu, Yating, Fu, Xiao, and Xu, Qin

Subjects
SHORT-chain fatty acids, MICROCIRCULATION disorders, CELL physiology, NITRIC oxide, NITRIC-oxide synthases, ENDOPLASMIC reticulum, RUMEN fermentation, FATTY acids
Abstract

Coronary microvascular dysfunction (CMD) is a critical pathogenesis of cardiovascular diseases. Lower endothelial nitric oxide synthase (eNOS) phosphorylation leads to reduced endothelium-derived relaxing factor nitric oxide (NO) generation, causing and accelerating CMD. Endoplasmic reticulum stress (ER stress) has been shown to reduce NO production in umbilical vein endothelial cells. Oxidized low-density lipoprotein (ox-LDL) damages endothelial cell function. However, the relationship between ox-LDL and coronary microcirculation has yet to be assessed. Short-chain fatty acid (SCFA), a fermentation product of the gut microbiome, could improve endothelial-dependent vasodilation in human adipose arterioles, but the effect of SCFA on coronary microcirculation is unclear. In this study, we found ox-LDL stimulated expression of ER chaperone GRP78. Further, we activated downstream PERK/eIF2a, IRE1/JNK, and ATF6 signaling pathways, decreasing eNOS phosphorylation and NO production in human cardiac microvascular endothelial. Furthermore, SCFA-propionate can inhibit ox-LDL-induced eNOS phosphorylation reduction and raise NO production; the mechanism is related to the inhibition of ER stress and downstream signaling pathways PERK/eIF2a, IRE1/JNK, and ATF6. In summary, we demonstrate that ox-LDL induced CMD by activating ER stress, propionate can effectively counteract the adverse effects of ox-LDL and protect coronary microcirculation function via inhibiting ER stress. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Structural and biochemical studies of a moderately thermophilic exonuclease I from Methylocaldum szegediense.

Author

Li Fei, SiSi Tian, Ruth Moysey, Mihaela Misca, John J Barker, Myron A Smith, Paul A McEwan, Ewa S Pilka, Lauren Crawley, Tom Evans, and Dapeng Sun

Subjects
Medicine, Science
Abstract

A novel exonuclease, designated as MszExo I, was cloned from Methylocaldum szegediense, a moderately thermophilic methanotroph. It specifically digests single-stranded DNA in the 3' to 5' direction. The protein is composed of 479 amino acids, and it shares 47% sequence identity with E. coli Exo I. The crystal structure of MszExo I was determined to a resolution of 2.2 Å and it aligns well with that of E. coli Exo I. Comparative studies revealed that MszExo I and E. coli Exo I have similar metal ion binding affinity and similar activity at mesophilic temperatures (25-47°C). However, the optimum working temperature of MszExo I is 10°C higher, and the melting temperature is more than 4°C higher as evaluated by both thermal inactivation assays and DSC measurements. More importantly, two thermal transitions during unfolding of MszExo I were monitored by DSC while only one transition was found in E. coli Exo I. Further analyses showed that magnesium ions not only confer structural stability, but also affect the unfolding of MszExo I. MszExo I is the first reported enzyme in the DNA repair systems of moderately thermophilic bacteria, which are predicted to have more efficient DNA repair systems than mesophilic ones.

Published
2015
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11. Network pharmacology and molecular docking reveal the effective substances and active mechanisms of Dalbergia Odoriferain protecting against ischemic stroke

Author

Liu, Kedi, primary, Tao, Xingru, additional, Su, Jing, additional, Li, Fei, additional, Mu, Fei, additional, Zhao, Shi, additional, Lu, Xinming, additional, Li, Jing, additional, Chen, Sha, additional, Dong, Taiwei, additional, Duan, Jialin, additional, Wei, Peifeng, additional, and Xi, Miaomiao, additional

Published
2021
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12. The endogenous nitric oxide mediates selenium-induced phytotoxicity by promoting ROS generation in Brassica rapa.

Author

Yi Chen, Hai-Zhen Mo, Liang-Bin Hu, You-Qin Li, Jian Chen, and Li-Fei Yang

Subjects
Medicine, Science
Abstract

Selenium (Se) is suggested as an emerging pollutant in agricultural environment because of the increasing anthropogenic release of Se, which in turn results in phytotoxicity. The most common consequence of Se-induced toxicity in plants is oxidative injury, but how Se induces reactive oxygen species (ROS) burst remains unclear. In this work, histofluorescent staining was applied to monitor the dynamics of ROS and nitric oxide (NO) in the root of Brassica rapa under Se(IV) stress. Se(IV)-induced faster accumulation of NO than ROS. Both NO and ROS accumulation were positively correlated with Se(IV)-induced inhibition of root growth. The NO accumulation was nitrate reductase (NR)- and nitric oxide synthase (NOS)-dependent while ROS accumulation was NADPH oxidase-dependent. The removal of NO by NR inhibitor, NOS inhibitor, and NO scavenger could alleviate Se(IV)-induced expression of Br_Rbohs coding for NADPH oxidase and the following ROS accumulation in roots, which further resulted in the amelioration of Se(IV)-induced oxidative injury and growth inhibition. Thus, we proposed that the endogenous NO played a toxic role in B. rapa under Se(IV) stress by triggering ROS burst. Such findings can be used to evaluate the toxic effects of Se contamination on crop plants.

Published
2014
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13. Selenium inhibits root elongation by repressing the generation of endogenous hydrogen sulfide in Brassica rapa.

Author

Yi Chen, Hai-Zhen Mo, Mei-Yu Zheng, Ming Xian, Zhong-Qiang Qi, You-Qin Li, Liang-Bin Hu, Jian Chen, and Li-Fei Yang

Subjects
Medicine, Science
Abstract

Selenium (Se) has been becoming an emerging pollutant causing severe phytotoxicity, which the biochemical mechanism is rarely known. Although hydrogen sulfide (H2S) has been suggested as an important exogenous regulator modulating plant physiological adaptions in response to heavy metal stress, whether and how the endogenous H2S regulates Se-induce phytotoxicity remains unclear. In this work, a self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H2S in situ in the roots of Brassica rapa under Se(IV) stress. Se(IV)-induced root growth stunt was closely correlated with the inhibition of endogenous H2S generation in root tips. Se(IV) stress dampened the expression of most LCD and DCD homologues in the roots of B. rapa. By using various specific fluorescent probes for bio-imaging root tips in situ, we found that the increase in endogenous H2S by the application of H2S donor NaHS could significantly alleviate Se(IV)-induced reactive oxygen species (ROS) over-accumulation, oxidative impairment, and cell death in root tips, which further resulted in the recovery of root growth under Se(IV) stress. However, dampening the endogenous H2S could block the alleviated effect of NaHS on Se(IV)-induced phytotoxicity. Finally, the increase in endogenous H2S resulted in the enhancement of glutathione (GSH) in Se(IV)-treated roots, which may share the similar molecular mechanism for the dominant role of H2S in removing ROS by activating GSH biosynthesis in mammals. Altogether, these data provide the first direct evidences confirming the pivotal role of endogenous H2S in modulating Se(IV)-induced phytotoxicity in roots.

Published
2014
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15. Matrix metalloproteinase-1 polymorphism (-1607G) and disease severity in non-cystic fibrosis bronchiectasis in Taiwan.

Author

Meng-Heng Hsieh, Pai-Chien Chou, Chun-Liang Chou, Shu-Chuan Ho, Wen-Ching Joa, Li-Fei Chen, Te-Fang Sheng, Horng-Chyuan Lin, Tsai-Yu Wang, Po-Jui Chang, Chun-Hua Wang, and Han-Pin Kuo

Subjects
Medicine, Science
Abstract

OBJECTIVES: Bronchiectasis is characterized by an irreversible dilatation of bronchi and is associated with lung fibrosis. MMP-1 polymorphism may alter its transcriptional activity, and differentially modulate bronchial destruction and lung fibrosis. DESIGN: To investigate the association of MMP-1 polymorphisms with disease severity in non-cystic fibrosis (CF) bronchiectasis patients, 51 normal subjects and 113 patients with bronchiectasis were studied. The associations between MMP-1 polymorphisms, lung function, and disease severity evaluated by high resolution computed tomography (HRCT) were analyzed. RESULTS: The frequency of MMP-1(-1607G) allele was significantly higher in patients with bronchiectasis than normal subjects (70.8% vs 45.1%, p

Published
2013
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20. A survey of argasid ticks and tick-associated pathogens in the Peripheral Oases around Tarim Basin and the first record of Argas japonicus in Xinjiang, China

Author

Zhao, Li, primary, Lin, Xiang-Mei, additional, Li, Fei, additional, Li, Kai-Rui, additional, He, Bo, additional, Zhang, Lu-Yao, additional, Pan, Jiao-Jiao, additional, Wang, Qiang-Rong, additional, Gao, Jia-Min, additional, Johnson, Nicholas, additional, Yuan, Xiang-Fen, additional, Lv, Ji-Zhou, additional, Wu, Shao-Qiang, additional, and Liu, Yong-Hong, additional

Published
2018
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23. Genome-wide identification of wheat (Triticum aestivum) expansins and expansin expression analysis in cold-tolerant and cold-sensitive wheat cultivars

Author

Zhang, Jun-Feng, primary, Xu, Yong-Qing, additional, Dong, Jia-Min, additional, Peng, Li-Na, additional, Feng, Xu, additional, Wang, Xu, additional, Li, Fei, additional, Miao, Yu, additional, Yao, Shu-Kuan, additional, Zhao, Qiao-Qin, additional, Feng, Shan-Shan, additional, Hu, Bao-Zhong, additional, and Li, Feng-Lan, additional

Published
2018
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33. Structural and biochemical studies of a moderately thermophilic exonuclease I from Methylocaldum szegediense

Author

Thomas C. Evans, Myron A. Smith, Paul A. McEwan, SiSi Tian, Li Fei, John Barker, Ruth Moysey, Dapeng Sun, Lauren Crawley, Ewa S. Pilka, and Mihaela Misca

Subjects
Exonuclease, Hot Temperature, DNA Repair, DNA repair, lcsh:Medicine, Sequence alignment, Biology, Crystallography, X-Ray, chemistry.chemical_compound, Bacterial Proteins, Hydrolase, Cloning, Molecular, lcsh:Science, Magnesium ion, chemistry.chemical_classification, Multidisciplinary, Thermophile, lcsh:R, Enzyme, Exodeoxyribonucleases, chemistry, Biochemistry, Methylococcaceae, biology.protein, lcsh:Q, DNA, Research Article
Abstract

A novel exonuclease, designated as MszExo I, was cloned from Methylocaldum szegediense, a moderately thermophilic methanotroph. It specifically digests single-stranded DNA in the 3ʹ to 5ʹ direction. The protein is composed of 479 amino acids, and it shares 47% sequence identity with E. coli Exo I. The crystal structure of MszExo I was determined to a resolution of 2.2 A and it aligns well with that of E. coli Exo I. Comparative studies revealed that MszExo I and E. coli Exo I have similar metal ion binding affinity and similar activity at mesophilic temperatures (25–47°C). However, the optimum working temperature of MszExo I is 10°C higher, and the melting temperature is more than 4°C higher as evaluated by both thermal inactivation assays and DSC measurements. More importantly, two thermal transitions during unfolding of MszExo I were monitored by DSC while only one transition was found in E. coli Exo I. Further analyses showed that magnesium ions not only confer structural stability, but also affect the unfolding of MszExo I. MszExo I is the first reported enzyme in the DNA repair systems of moderately thermophilic bacteria, which are predicted to have more efficient DNA repair systems than mesophilic ones.

Published
2015

44. Good exemplars of natural scene categories elicit clearer patterns than bad exemplars but not greater BOLD activity

Author

Li Fei-Fei, Eamon Caddigan, Ana Torralbo, Diane M. Beck, Barry Chai, and Dirk B. Walther

Subjects
Adult, Male, Behavioral experiment, Visual System, Cognitive Neuroscience, Science, Emotions, Neuroimaging, Biology, Social and Behavioral Sciences, Bioinformatics, Models, Biological, 050105 experimental psychology, 03 medical and health sciences, Cognition, 0302 clinical medicine, Functional neuroimaging, Psychology, Humans, Bold fmri, Natural (music), 0501 psychology and cognitive sciences, Behavior, Multidisciplinary, business.industry, Functional Neuroimaging, fMRI, 05 social sciences, Cognitive Psychology, Experimental Psychology, Pattern recognition, Variance (accounting), Sensory Systems, Pattern Recognition, Visual, Categorization, Medicine, Female, Artificial intelligence, business, Classifier (UML), 030217 neurology & neurosurgery, Research Article, Neuroscience
Abstract

Within the range of images that we might categorize as a "beach", for example, some will be more representative of that category than others. Here we first confirmed that humans could categorize "good" exemplars better than "bad" exemplars of six scene categories and then explored whether brain regions previously implicated in natural scene categorization showed a similar sensitivity to how well an image exemplifies a category. In a behavioral experiment participants were more accurate and faster at categorizing good than bad exemplars of natural scenes. In an fMRI experiment participants passively viewed blocks of good or bad exemplars from the same six categories. A multi-voxel pattern classifier trained to discriminate among category blocks showed higher decoding accuracy for good than bad exemplars in the PPA, RSC and V1. This difference in decoding accuracy cannot be explained by differences in overall BOLD signal, as average BOLD activity was either equivalent or higher for bad than good scenes in these areas. These results provide further evidence that V1, RSC and the PPA not only contain information relevant for natural scene categorization, but their activity patterns mirror the fundamentally graded nature of human categories. Analysis of the image statistics of our good and bad exemplars shows that variability in low-level features and image structure is higher among bad than good exemplars. A simulation of our neuroimaging experiment suggests that such a difference in variance could account for the observed differences in decoding accuracy. These results are consistent with both low-level models of scene categorization and models that build categories around a prototype.

Published
2013

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