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33. HAD-GAN: A Human-perception Auxiliary Defense GAN to Defend Adversarial Examples

Author

Yu, Wanting, Yu, Hongyi, Jiang, Lingyun, Zhang, Mengli, and Qiao, Kai

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Machine Learning, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Adversarial examples reveal the vulnerability and unexplained nature of neural networks. Studying the defense of adversarial examples is of considerable practical importance. Most adversarial examples that misclassify networks are often undetectable by humans. In this paper, we propose a defense model to train the classifier into a human-perception classification model with shape preference. The proposed model comprising a texture transfer network (TTN) and an auxiliary defense generative adversarial networks (GAN) is called Human-perception Auxiliary Defense GAN (HAD-GAN). The TTN is used to extend the texture samples of a clean image and helps classifiers focus on its shape. GAN is utilized to form a training framework for the model and generate the necessary images. A series of experiments conducted on MNIST, Fashion-MNIST and CIFAR10 show that the proposed model outperforms the state-of-the-art defense methods for network robustness. The model also demonstrates a significant improvement on defense capability of adversarial examples.

Published
2019

40. SIRT5 deficiency suppresses mitochondrial ATP production and promotes AMPK activation in response to energy stress.

Author

Zhang, Mengli, Wu, Jian, Sun, Renqiang, Tao, Xiaoting, Wang, Xiaoxia, Kang, Qi, Wang, Hui, Zhang, Lei, Liu, Peng, Zhang, Jinye, Xia, Yukun, Zhao, Yuzheng, Yang, Yi, Xiong, Yue, Guan, Kun-Liang, Zou, Yunzeng, and Ye, Dan

Subjects
Mitochondria, Heart, Animals, Mice, Knockout, Humans, Mice, Cardiomegaly, Sirtuins, Adenosine Triphosphate, Enzyme Activation, Stress, Physiological, AMP-Activated Protein Kinases, HEK293 Cells, Knockout, Mitochondria, Heart, Stress, Physiological, General Science & Technology
Abstract

Sirtuin 5 (SIRT5) is a member of the NAD+-dependent sirtuin family of protein deacylase that catalyzes removal of post-translational modifications, such as succinylation, malonylation, and glutarylation on lysine residues. In light of the SIRT5's roles in regulating mitochondrion function, we show here that SIRT5 deficiency leads to suppression of mitochondrial NADH oxidation and inhibition of ATP synthase activity. As a result, SIRT5 deficiency decreases mitochondrial ATP production, increases AMP/ATP ratio, and subsequently activates AMP-activated protein kinase (AMPK) in cultured cells and mouse hearts under energy stress conditions. Moreover, Sirt5 knockout attenuates transverse aortic constriction (TAC)-induced cardiac hypertrophy and cardiac dysfunction in mice, which is associated with decreased ATP level, increased AMP/ATP ratio and enhanced AMPK activation. Our study thus uncovers an important role of SIRT5 in regulating cellular energy metabolism and AMPK activation in response to energy stress.

Published
2019

48. Structure, Function and Engineering of the Nonribosomal Peptide Synthetase Condensation Domain.

Author

Huang, Zhenkuai, Peng, Zijing, Zhang, Mengli, Li, Xinhai, and Qiu, Xiaoting

Subjects
PEPTIDES, CATALYTIC domains, BIOCHEMICAL substrates, NATURAL products, CONDENSATION
Abstract

The nonribosomal peptide synthetase (NRPS) is a highly precise molecular assembly machinery for synthesizing structurally diverse peptides, which have broad medicinal applications. Withinthe NRPS, the condensation (C) domain is a core catalytic domain responsible for the formation of amide bonds between individual monomer residues during peptide elongation. This review summarizes various aspects of the C domain, including its structural characteristics, catalytic mechanisms, substrate specificity, substrate gating function, and auxiliary functions. Moreover, through case analyses of the NRPS engineering targeting the C domains, the vast potential of the C domain in the combinatorial biosynthesis of peptide natural product derivatives is demonstrated. [ABSTRACT FROM AUTHOR]

Published
2024
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49. Ultra-High-Performance Liquid Chromatography–High-Definition Mass Spectrometry-Based Metabolomics to Reveal the Potential Anti-Arthritic Effects of Illicium verum in Cultured Fibroblast-like Synoviocytes Derived from Rheumatoid Arthritis.

Author

Qin, Mingzhen, Chen, Lu, Hou, Xiaoli, Wu, Wuwei, Liu, Yu, Pan, Yu, Zhang, Mengli, Tan, Zhien, and Huang, Danna

Subjects
LIQUID chromatography-mass spectrometry, RHEUMATOID arthritis, AUTOIMMUNE diseases, METABOLOMICS, MASS spectrometry
Abstract

Background: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. The fruits of Illicium verum, which is a medicinal and edible resource, have been shown to have anti-inflammatory properties. Methods: In this study, we investigated the effects of I. verum extracts (IVEs) on human RA fibroblasts-like synoviocytes (RA-FLS) by using a sensitive and selective ultra-high-performance liquid chromatography with high-definition mass spectrometry (UPLC-HDMS) method. We subsequently analyzed the metabolites produced after the incubation of cultured RA-FLS with IVEs. Results: IVEs inhibited the proliferation and suppressed the migration of RA-FLS, and reduced the levels of inflammatory factors including TNF-α and IL-6. Twenty differential metabolites responsible for the effects of IVEs were screened and annotated based on the UPLC-HDMS data by using a cell metabolomics approach. Discussion: Our findings suggest that treating RA-FLS with IVEs can regulate lipid and amino acid metabolism, indicating that this extract has the potential to modify the metabolic pathways that cause inflammation in RA. Conclusions: This might lead to novel therapeutic strategies for managing patients with RA. [ABSTRACT FROM AUTHOR]

Published
2024
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