283 research outputs found
Boosting Few-shot Action Recognition with Graph-guided Hybrid Matching
Class prototype construction and matching are core aspects of few-shot action
recognition. Previous methods mainly focus on designing spatiotemporal relation
modeling modules or complex temporal alignment algorithms. Despite the
promising results, they ignored the value of class prototype construction and
matching, leading to unsatisfactory performance in recognizing similar
categories in every task. In this paper, we propose GgHM, a new framework with
Graph-guided Hybrid Matching. Concretely, we learn task-oriented features by
the guidance of a graph neural network during class prototype construction,
optimizing the intra- and inter-class feature correlation explicitly. Next, we
design a hybrid matching strategy, combining frame-level and tuple-level
matching to classify videos with multivariate styles. We additionally propose a
learnable dense temporal modeling module to enhance the video feature temporal
representation to build a more solid foundation for the matching process. GgHM
shows consistent improvements over other challenging baselines on several
few-shot datasets, demonstrating the effectiveness of our method. The code will
be publicly available at https://github.com/jiazheng-xing/GgHM.Comment: Accepted by ICCV202
Hfq Is a Global Regulator That Controls the Pathogenicity of Staphylococcus aureus
The Hfq protein is reported to be an RNA chaperone, which is involved in the stress response and the virulence of several pathogens. In E. coli, Hfq can mediate the interaction between some sRNAs and their target mRNAs. But it is controversial whether Hfq plays an important role in S. aureus. In this study, we found that the deletion of hfq gene in S. aureus 8325-4 can increase the surface carotenoid pigments. The hfq mutant was more resistant to oxidative stress but the pathogenicity of the mutant was reduced. We reveal that the Hfq protein can be detected only in some S. aureus strains. Using microarray and qRT-PCR, we identified 116 genes in the hfq mutant which had differential expression from the wild type, most of which are related to the phenotype and virulence of S. aureus. Among the 116 genes, 49 mRNAs can specifically bind Hfq protein, which indicates that Hfq also acts as an RNA binding protein in S. aureus. Our data suggest that Hfq protein of S. aureus is a multifunctional regulator involved in stress and virulence
ROS Promote Ox-LDL-Induced Platelet Activation by Up-Regulating Autophagy Through the Inhibition of the PI3K/AKT/mTOR Pathway
Background/Aims: Oxidized low-density lipoprotein (oxLDL) promotes unregulated platelet activation in patients with dyslipidemic disorders. Although oxLDL stimulates activating signaling, researchers have not clearly determined how these events drive accelerated thrombosis. Here, we describe the mechanism by which ROS regulate autophagy during ox-LDL-induced platelet activation by modulating the PI3K/AKT/mTOR signaling pathway. Methods: For in vitro experiments, ox-LDL, the ROS scavenger N-acetylcysteine (NAC), the mTOR inhibitor rapamycin and the autophagy inhibitor 3-MA were used alone or in combination with other compounds to treat platelets. Then, platelet aggregation was evaluated on an aggregometer and platelet adhesion was measured under shear stress. The levels of a platelet activation marker (CD62p) were measured by flow cytometry, reactive oxygen species (ROS) levels were then quantified by measuring DCFH-DA fluorescence intensity via flow cytometry. Nitric oxide (NO) and superoxide (O2·-) levels were determined by the nitric acid deoxidize enzyme method and lucigenin-enhanced chemiluminescence (CL), respectively. Transmission electron microscopy was used to observe the autophagosome formation, immunofluorescence staining was employed to detect LC3 expression and western blotting was used to measure the levels of PI3K/AKT/mTOR pathway- and autophagy-related proteins. Results: Ox-LDL-induced platelets showed a significant increase in platelet aggregation and adhesion, CD62p expression, ROS level and O2·- content, with an elevated LC3II/LC3I ratio and Beclin1 expression, but a dramatic reduction in the levels of p62 and pathway-related proteins (all P < 0.05). However, platelet activation and autophagy were aggravated by the Rapamycin treatment, and decreased following treatment with NAC, 3-MA, or NAC and 3-MA, together with increased activity of the PI3K/AKT/mTOR pathway. Additionally, decreased platelet activation and autophagy were observed in platelets treated with NAC and Rapamycin or Rapamycin and 3-MA compared with platelets treated with Rapamycin alone, suggesting that both NAC and 3-MA reversed the effects of Rapamycin. Conclusion: Inhibition of ROS production may reduce autophagy to suppress ox-LDL-induced platelet activation by activating PI3K/AKT/mTOR pathway
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