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357 results on '"Zhao, Yimeng"'

52. High-Speed Atomic Force Microscopy Reveals Fluctuations and Dimer Splitting of the N-Terminal Domain of GluA2 Ionotropic Glutamate Receptor-Auxiliary Subunit Complex

Author

Sumino, Ayumi, Sumikama, Takashi, Zhao, Yimeng, Flechsig, Holger, Umeda, Kenichi, Kodera, Noriyuki, Konno, Hiroki, Hattori, Motoyuki, and Shibata, Mikihiro

Abstract

α-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid glutamate receptors (AMPARs) enable rapid excitatory synaptic transmission by localizing to the postsynaptic density of glutamatergic spines. AMPARs possess large extracellular N-terminal domains (NTDs), which are crucial for AMPAR clustering at synaptic sites. However, the dynamics of NTDs and the molecular mechanism governing their synaptic clustering remain elusive. Here, we employed high-speed atomic force microscopy (HS-AFM) to directly visualize the conformational dynamics of NTDs in the GluA2 subunit complexed with TARP γ2 in lipid environments. HS-AFM videos of GluA2-γ2 in the resting and activated/open states revealed fluctuations in NTD dimers. Conversely, in the desensitized/closed state, the two NTD dimers adopted a separated conformation with less fluctuation. Notably, we observed individual NTD dimers transitioning into monomers, with extended monomeric states in the activated/open state. Molecular dynamics simulations provided further support, confirming the energetic stability of the monomeric NTD states within lipids. This NTD-dimer splitting resulted in subunit exchange between the receptors and increased the number of interaction sites with synaptic protein neuronal pentraxin 1 (NP1). Moreover, our HS-AFM studies revealed that NP1 forms a ring-shaped octamer through N-terminal disulfide bonds and binds to the tip of the NTD. These findings suggest a molecular mechanism in which NP1, upon forming an octamer, is secreted into the synaptic region and binds to the tip of the GluA2 NTD, thereby bridging and clustering multiple AMPARs. Thus, our findings illuminate the critical role of NTD dynamics in the synaptic clustering of AMPARs and contribute valuable insights into the fundamental processes of synaptic transmission.

Published
2024
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56. Piperine improves levodopa availability in the 6‐OHDA‐lesioned rat model of Parkinson's disease by suppressing gut bacterial tyrosine decarboxylase.

Author

Hu, Xiaolu, Yu, Lan, Li, Yatong, Li, Xiaoxi, Zhao, Yimeng, Xiong, Lijuan, Ai, Jiaxuan, Chen, Qijun, Wang, Xing, Chen, Xiaoqing, Ba, Yinying, Wang, Yaonan, and Wu, Xia

Subjects
PARKINSON'S disease, CARBIDOPA, TYROSINE, DOPA, ORAL drug administration, ANIMAL disease models
Abstract

Aim: Tyrosine decarboxylase (TDC) presented in the gut‐associated strain Enterococcus faecalis can convert levodopa (L‐dopa) into dopamine (DA), and its increased abundance would potentially minimize the availability and efficacy of L‐dopa. However, the known human decarboxylase inhibitors are ineffective in this bacteria‐mediated conversion. This study aims to investigate the inhibition of piperine (PIP) on L‐dopa bacterial metabolism and evaluates the synergistic effect of PIP combined with L‐dopa on Parkinson's disease (PD). Methods: Metagenomics sequencing was adopted to determine the regulation of PIP on rat intestinal microbiota structure, especially on the relative abundance of E. faecalis. Then, the inhibitory effects of PIP on L‐dopa conversion and TDC expression of E. faecalis were tested in vitro. We examined the synergetic effect of the combination of L‐dopa and PIP on 6‐hydroxydopamine (6‐OHDA)‐lesioned rats and tested the regulations of L‐dopa bioavailability and brain DA level by pharmacokinetics study and MALDI‐MS imaging. Finally, we evaluated the microbiota‐dependent improvement effect of PIP on L‐dopa availability using pseudo‐germ‐free and E. faecalis‐transplanted rats. Results: We found that PIP combined with L‐dopa could better ameliorate the move disorders of 6‐OHDA‐lesioned rats by remarkably improving L‐dopa availability and brain DA level than L‐dopa alone, which was associated with the effect of PIP on suppressing the bacterial decarboxylation of L‐dopa via effectively downregulating the abnormal high abundances of E. faecalis and TDC in 6‐OHDA‐lesioned rats. Conclusion: Oral administration of L‐dopa combined with PIP can improve L‐dopa availability and brain DA level in 6‐OHDA‐lesioned rats by suppressing intestinal bacterial TDC. [ABSTRACT FROM AUTHOR]

Published
2024
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58. Piperine improves levodopa availability in the6‐OHDA‐lesioned rat model of Parkinson's disease by suppressing gut bacterial tyrosine decarboxylase

Author

Hu, Xiaolu, primary, Yu, Lan, additional, Li, Yatong, additional, Li, Xiaoxi, additional, Zhao, Yimeng, additional, Xiong, Lijuan, additional, Ai, Jiaxuan, additional, Chen, Qijun, additional, Wang, Xing, additional, Chen, Xiaoqing, additional, Ba, Yinying, additional, Wang, Yaonan, additional, and Wu, Xia, additional

Published
2023
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63. Enhanced thermal constant Bof diamond films for ultrahigh sensitivity negative temperature coefficient thermistors

Author

Chen, Qiao, Zhao, Yimeng, Li, Jiawei, Liu, Xiyuan, Wang, Xinyue, Zhang, Wenxi, and Zhu, Hongwei

Abstract

Negative temperature coefficient (NTC) thermistor plays a crucial role in science research and engineering applications for precise temperature monitoring. Although great progress has been achieved in NTC materials, enhancing sensitivity and maintaining this high sensitivity along with linearity across extensive temperature ranges remain a significant challenge. In this study, we introduce a diamond-based thermistor (DT) characterized by its outstanding sensitivity, swift response time, and broad temperature monitoring capabilities. The temperature constant Bfor this DT, measured from 30 to 300°C (B30/300), achieves an exceptional value of 8012 K, which notably exceeds the temperature sensing capabilities of previously reported NTC thermistors within this extensive range. Moreover, diamond’s unique thermal conductivity and stability significantly boost the response speed and durability of the DT, offering substantial advantages over traditional ceramic thermistors. The enhanced temperature-sensitive properties of the DT are attributed to the presence of impurity elements in polycrystalline diamond. Impedance analysis indicates a hopping conduction mechanism, likely involving C-H or C-N dipoles at the diamond grain boundaries. This study marks a significant leap forward in diamond thermistor technology and sheds light on the mechanisms of thermal active conduction in diamond materials.

Published
2024
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65. Microfluidic Chip Integrated with Hydrogel Microparticles and CdS Cation Interfacial Exchange for the Sensitive Determination of miRNA.

Author

Zhao, Yimeng, Lv, Xuefei, Peng, Zhao, Zhao, Kexin, Zhou, Di, and Deng, Yulin

Subjects
*MICRORNA, *POLYETHYLENE glycol, *DETECTION limit, *CATIONS, *PROGNOSIS
Abstract

Abnormally expressed miRNAs have been employed as crucial indicators for the diagnosis and prognosis of disease. It is essential to develop quick, affordable, accurate, and multiplexed methods for miRNA detection. In this study, polyethylene glycol (PEG) hydrogel microparticles were used as solid-phase carriers for the hybridization chain reaction (HCR) in combination with cation-exchange fluorescence amplification, thus enabling the development of a new method for miRNA determination. The assay was sensitive with the detection limit for miRNA let7a equal to 46 pM. The assay was specific, the base-mismatched sequences of miRNA let7a were distinguished, and the serum matrix did not cause any interference. Moreover, by integration with a microfluidic chip, the throughput was significantly enhanced and the process was noticeably simplified. With further development, the developed method may be suitable for practical clinical analysis. [ABSTRACT FROM AUTHOR]

Published
2023
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86. DARI-Mark: Deep Learning and Attention Network for Robust Image Watermarking.

Author

Zhao, Yimeng, Wang, Chengyou, Zhou, Xiao, and Qin, Zhiliang

Subjects
*DEEP learning, *WATERMARKS, *DIGITAL watermarking, *COMPUTER vision, *IMAGE processing, *SET functions, *MACHINE learning
Abstract

At present, deep learning has achieved excellent achievements in image processing and computer vision and is widely used in the field of watermarking. Attention mechanism, as the research hot spot of deep learning, has not yet been applied in the field of watermarking. In this paper, we propose a deep learning and attention network for robust image watermarking (DARI-Mark). The framework includes four parts: an attention network, a watermark embedding network, a watermark extraction network, and an attack layer. The attention network used in this paper is the channel and spatial attention network, which calculates attention weights along two dimensions, channel and spatial, respectively, assigns different weights to pixels in different channels at different positions and is applied in the watermark embedding and watermark extraction stages. Through end-to-end training, the attention network can locate nonsignificant areas that are insensitive to the human eye and assign greater weights during watermark embedding, and the watermark embedding network selects this region to embed the watermark and improve the imperceptibility. In watermark extraction, by setting the loss function, larger weights can be assigned to watermark-containing features and small weights to noisy signals, so that the watermark extraction network focuses on features about the watermark and suppresses noisy signals in the attacked image to improve robustness. To avoid the phenomenon of gradient disappearance or explosion when the network is deep, both the embedding network and the extraction network have added residual modules. Experiments show that DARI-Mark can embed the watermark without affecting human subjective perception and that it has good robustness. Compared with other state-of-the-art watermarking methods, the proposed framework is more robust to JPEG compression, sharpening, cropping, and noise attacks. [ABSTRACT FROM AUTHOR]

Published
2023
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89. Psychological Interventions for Prevention of Depression Relapse: Systematic Review and Network Meta-Analysis

Author

Zhou, Yurong, primary, Zhao, Defeng, additional, Zhu, Xiaotong, additional, Liu, Lu, additional, Meng, Ming, additional, Shao, Xiaojun, additional, Zhu, Xueyan, additional, Xiang, Jing, additional, He, Jiali, additional, Zhao, Yimeng, additional, Yuan, Yuman, additional, Gao, Rui, additional, Jiang, Lin, additional, and Zhu, Gang, additional

Published
2022
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92. Tektin makes a microtubule a "micropillar".

Author

Gu, Yuzhong, Zhao, Yimeng, and Ichikawa, Muneyoshi

Subjects
*SPERMATOZOA, *FLAGELLA (Microbiology), *MICROTUBULES
Abstract

Inside sperm flagella, there are nine doublet microtubules composed of A and B tubules. In this issue of Cell , Leung et al. and Zhou et al. present high-resolution cryo-EM structures of doublet microtubules from mammalian sperms and show unprecedented structures of the A tubules, which are almost entirely occupied with tektin bundles. [ABSTRACT FROM AUTHOR]

Published
2023
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