Abstract Many enveloped viruses utilize endocytic pathways and vesicle trafficking to infect host cells, where the acidification of virus‐containing endosomes triggers the virus‐endosome fusion events. Therefore, simultaneous correlation of intracellular location, local pH, and individual virus dynamics is important for gaining insight into viral infection mechanisms. Here, an imaging approach is developed for spatiotemporal quantification of endosomal acidification on the viral journey in host cells using a fluorescence resonance energy transfer based ratiometric pH sensor consisting of a photostable and high‐brightness QD, pH‐sensitive fluorescent dyes, and virus‐binding proteins. Ratiometric analysis of sensor‐based single‐virus tracking data enables to dissect a two‐step endosomal acidification process during the infection of influenza viruses and elucidates the occurrence of the fission and sorting of virus‐containing endosomes to recycling endosomes after initial acidification. This technique should serve as a robust approach for in situ quantification of endosomal acidification on the viral journey.
Activation of class I phosphatidylinositol 3-kinase (PI3K) leads to formation of phosphatidylinositol-3,4,5-trisphophate (PIP3) and phosphatidylinositol-3,4-bisphophate (PI34P2), which spatiotemporally coordinate and regulate a myriad of cellular processes. By simultaneous quantitative imaging of PIP3 and PI34P2 in live cells, we here show that they have a distinctively different spatiotemporal distribution and history in response to growth factor stimulation, which allows them to selectively induce the membrane recruitment and activation of Akt isoforms. PI34P2 selectively activates Akt2 at both the plasma membrane and early endosomes, whereas PIP3 selectively stimulates Akt1 and Akt3 exclusively at the plasma membrane. These spatiotemporally distinct activation patterns of Akt isoforms provide a mechanism for their differential regulation of downstream signaling molecules. Collectively, our studies show that different spatiotemporal dynamics of PIP3 and PI34P2 and their ability to selectively activate key signaling proteins allow them to mediate class I PI3K signaling pathways in a spatiotemporally specific manner.
PURPOSE The purpose of this study is to establish a structural equation model of the influence of risk perception on satisfaction and behavioral intention of cycling into Tibet, and to verify the relationship between natural risk, social risk, cultural risk, organizational risk, satisfaction and behavioral intention. METHOD Taking cycling into Tibet as the background, people cycling into Tibet in the past three years were taken as the main research samples. A total of 380 questionnaires were collected online for research and analysis through the WJX questionnaire network platform. Descriptive statistics, exploratory factor analysis, confirmatory factor analysis and structural equation model were used to analyze the collected data. RESULT The results showed that (1) cyclists cycling into Tibet were engaged in serious leisure and their natural risk perception positively affected their behavioral intentions. (2) satisfaction was an important predictor of their behavioral intentions cycling into Tibet. (3) social, cultural and organizational risk negatively affected satisfaction. CONCLUSION Satisfaction is an important factor in the behavior intention of cycling into Tibet. The results of this study provided some practical suggestions for the organization and management of cycling into Tibet, as well as suggestions for future studies, such as theoretical supports for tourists'' behavioral intentions like revisiting Tibet.
Uncovering the mechanisms of virus infection and assembly is crucial for preventing the spread of viruses and treating viral disease. The technique of single-virus tracking (SVT), also known as single-virus tracing, allows one to follow individual viruses at different parts of their life cycle and thereby provides dynamic insights into fundamental processes of viruses occurring in live cells. SVT is typically based on fluorescence imaging and reveals insights into previously unreported infection mechanisms. In this review article, we provide the readers a broad overview of the SVT technique. We first summarize recent advances in SVT, from the choice of fluorescent labels and labeling strategies to imaging implementation and analytical methodologies. We then describe representative applications in detail to elucidate how SVT serves as a valuable tool in virological research. Finally, we present our perspectives regarding the future possibilities and challenges of SVT.
Objective To explore the clinical effects of Magnesium Valproate used in 151 cases of patients with epileptic caused by trauma.Methods 151 cases of epileptic patients were divided into group A,B and C according to disease type.Group A(51 cases)was patients of partial seizures;Group C(50 cases) was patients of generalized seizures;Group B(50 cases) was patients of generalized seizures caused by partial seizures.Each patient was given individualized therapy according to weight and Tolerance conditions.Results After treatment,excellence rates between 3 groups have very significant differences(P0.01),total efficiency rates have significant differences(P0.05).Clinical effect from high to low was: A,B,C.Conclusion Patients with epileptic should be diagnosed early and given individualized therapy according to concrete states,to the aim of improving prognosis in best greatest degree.
Entry is the first critical step for the infection of influenza A virus and of great significance for the research and development of antiflu drugs. Influenza A virus depends on exploitation of cellular endocytosis to enter its host cells, and its entry behaviors in distinct routes still need further investigation. With the aid of a single-virus tracking technique and quantum dots, we have realized real-time and multicolor visualization of the endocytic process of individual viruses and comprehensive dissection of two distinct dynamin-dependent endocytic pathways of influenza A virus, either dependent on clathrin or not. Based on the sequential progression of protein recruitment and viral motility, we have revealed the asynchronization in the recruitments of clathrin and dynamin during clathrin-dependent entry of the virus, with a large population of events for short-lived recruitments of these two proteins being abortive. In addition, the differentiated durations of dynamin recruitment and responses to inhibitors in these two routes have evidenced somewhat different roles of dynamin. Besides promoting membrane fission in both entry routes, dynamin also participates in the maturation of a clathrin-coated pit in the clathrin-dependent route. Collectively, the current study displays a dynamic and precise image of the entry process of influenza A virus and elucidates the mechanisms of distinct entry routes. This quantum dot-based single-virus tracking technique is proven to be well-suited for investigating the choreographed interactions between virus and cellular proteins.
Exosomes play an important role in the spread of viral infections and immune escape. However, the exact ability and mechanisms by which exosomes produced during viral infections (vExos) infect host cells are still not fully understood. In this study, we developed a dual-color exosome labeling strategy that simultaneously labels the external and internal structures of exosomes with quantum dots to enable in situ monitoring of the transport process of vExos in live cells using the single-particle tracking technique. Our finding revealed that vExos contains the complete influenza A virus (IAV) genome and viral ribonucleoprotein complexes (vRNPs) proteins but lacks viral envelope proteins. Notably, these vExos have the ability to infect cells and produce progeny viruses. We also found that vExos are transported in three stages, slow-fast-slow, and move to the perinuclear region via microfilaments and microtubules. About 30% of internalized vExos shed the external membrane and release the internal vRNPs into the cytoplasm by fusion with endolysosomes. This study suggested that vExos plays a supporting role in IAV infection by assisting with IAV propagation in a virus-independent manner. It emphasizes the need to consider the infectious potential of vExos and draws attention to the potential risk of exosomes produced by viral infections.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'/%3e%3cuse xlink:href='%23a' transform='rotate(60)'/%3e%3ccircle r='17' fill='%23000095'/%3e%3ccircle r='15' fill='%23fff'/%3e%3c/svg%3e)