RESUMEN
Yeast two-hybrid (YTH) technology is a powerful tool for studying protein interactions and has been widely used in various fields of molecular biology, including the study of antiviral innate immunity. This chapter presents detailed information and experimental procedures for identifying virus-host protein interactions involved in immune regulation using yeast two-hybrid technology.
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Interacciones Huésped-Patógeno , Inmunidad Innata , Técnicas del Sistema de Dos Híbridos , Humanos , Interacciones Huésped-Patógeno/inmunología , Proteínas Virales/inmunología , Proteínas Virales/metabolismo , Saccharomyces cerevisiae/inmunología , Saccharomyces cerevisiae/genética , Unión Proteica , Mapeo de Interacción de Proteínas/métodosRESUMEN
The inefficiency observed in investment within state-owned enterprises presents a significant practical challenge that can affect the sustainable development of China's economy. To address this issue, this study comprehensively explores the intricate mechanisms underlying the governance implications of mixed ownership on the investment efficiency of listed companies. Drawing on unbalanced panel data encompassing Shanghai and Shenzhen Stock Exchange A-share listed companies in China spanning the period from 2008 to 2022, this study employs a fixed-effects model to unveil the nuanced ways in which mixed ownership influences investment efficiency through the lens of agency costs. This study transcends the boundaries of traditional agency conflicts between managers and shareholders. It delves deeper, illuminating the diverse effects of agency conflicts between significant controlling shareholders and minority shareholders. The results revealed a noteworthy positive correlation between mixed ownership and investment efficiency, and verified the intermediary role of agency costs between mixed ownership and investment efficiency, which is an important result of our research. Heterogeneity analysis indicates that the relationship between the two can be affected by external events, such as during the COVID-19 pandemic, investment efficiency is not the most concerned issue for enterprises. The findings have practical implications for practitioners and policymakers, as they offer avenues for optimizing investment strategies and fostering efficient and effective corporate governance practices.
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COVID-19 , Inversiones en Salud , Propiedad , China , Inversiones en Salud/economía , Propiedad/economía , Humanos , COVID-19/economía , COVID-19/epidemiología , SARS-CoV-2 , Pandemias/economíaRESUMEN
Human cytomegalovirus (HCMV), a widely prevalent human beta-herpesvirus, establishes lifelong persistence in the host following primary infection. In healthy individuals, the virus is effectively controlled by HCMV-specific T cells and typically exhibits asymptomatic. The T cell immune response plays a pivotal role in combating HCMV infection, while HCMV employs various strategies to counteract it within the host. Previously, we reported that UL23, a tegument protein of HCMV, facilitates viral immune evasion from interferon-gamma (IFN-γ) responses, and it is well known that IFN-γ is mainly derived from T cells. However, the involvement of UL23 in viral immune evasion from T cell-mediated immunity remains unclear. Herein, we present compelling evidence that UL23 significantly enhances viral resistance against T cell-mediated cytotoxicity during HCMV infection from the co-culture assays of HCMV-infected cells with T cells. We found that IFN-γ plays a major role in regulating T cell cytotoxicity mediated by UL23. More interestingly, we demonstrated that UL23 not only regulates the IFN-γ downstream responses but also modulates the IFN-γ secretion by regulating T cell activities. Further experiments indicate that UL23 upregulates the expression and signaling of programmed death ligand 1 (PD-L1), which is responsible for inhibiting multiple aspects of T cell activities, including activation, apoptosis, and IFN-γ secretion, as determined through RNA-seq analysis and inhibitor-blocking experiments, ultimately facilitating viral replication and spread. Our findings highlight the potential role of UL23 as an alternative antagonist in suppressing T cell cytotoxicity and unveil a novel strategy for HCMV to evade T cell immunity. IMPORTANCE: T cell immunity is pivotal in controlling primary human cytomegalovirus (HCMV) infection, restricting periodic reactivation, and preventing HCMV-associated diseases. Despite inducing a robust T cell immune response, HCMV has developed sophisticated immune evasion mechanisms that specifically target T cell responses. Although numerous studies have been conducted on HCMV-specific T cells, the primary focus has been on the impact of HCMV on T cell recognition via major histocompatibility complex molecules. Our studies show for the first time that HCMV exploits the programmed death ligand 1 (PD-L1) inhibitory signaling pathway to evade T cell immunity by modulating the activities of T cells and thereby blocking the secretion of IFN-γ, which is directly mediated by HCMV-encoded tegument protein UL23. While PD-L1 has been extensively studied in the context of tumors and viruses, its involvement in HCMV infection and viral immune evasion is rarely reported. We observed an upregulation of PD-L1 in normal cells during HCMV infection and provided strong evidence supporting its critical role in UL23-induced inhibition of T cell-mediated cytotoxicity. The novel strategy employed by HCMV to manipulate the inhibitory signaling pathway of T cell immune activation for viral evasion through its encoded protein offers valuable insights for the understanding of HCMV-mediated T cell immunomodulation and developing innovative antiviral treatment strategies.
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Antígeno B7-H1 , Infecciones por Citomegalovirus , Citomegalovirus , Evasión Inmune , Interferón gamma , Transducción de Señal , Humanos , Citomegalovirus/inmunología , Citomegalovirus/fisiología , Antígeno B7-H1/metabolismo , Antígeno B7-H1/genética , Antígeno B7-H1/inmunología , Interferón gamma/inmunología , Interferón gamma/metabolismo , Infecciones por Citomegalovirus/inmunología , Infecciones por Citomegalovirus/virología , Linfocitos T/inmunología , Linfocitos T/virología , Proteínas Virales/metabolismo , Proteínas Virales/inmunología , Proteínas Virales/genéticaRESUMEN
Edwardsiella tarda is a facultative intracellular pathogen in humans and animals. The Gram-negative bacterium is widely considered a potentially important bacterial pathogen. Adaptation to acid stress is important for the transmission of intestinal microbes, so the acid-resistance (AR) system is essential. However, the AR systems of E. tarda are totally unknown. In this study, a lysine-dependent acid resistance (LDAR) system in E. tarda, CadBA, was characterized and identified. CadB is a membrane protein and shares high homology with the lysine/cadaverine antiporter. CadA contains a PLP-binding core domain and a pyridoxal phosphate-binding motif. It shares high homology with lysine decarboxylase. cadB and cadA are co-transcribed under one operon. To study the function of the cadBA operon, isogenic cadA, cadB and cadBA deletion mutant strains TX01ΔcadA, TX01ΔcadB and TX01ΔcadBA were constructed. When cultured under normal conditions, the wild type strain and three mutants exhibited the same growth performance. However, when cultured under acid conditions, the growth of three mutants, especially TX01ΔcadA, were obviously retarded, compared to the wild strain TX01, which indicates the important involvement of the cadBA operon in acid resistance. The deletion of cadB or cadA, especially cadBA, significantly attenuated bacterial activity of lysine decarboxylase, suggesting the vital participation of cadBA operon in lysine metabolism, which is closely related to acid resistance. The mutations of cadBA operon enhanced bacterial biofilm formation, especially under acid conditions. The deletions of the cadBA operon reduced bacterial adhesion and invasion to Hela cells. Consistently, the deficiency of cadBA operon abated bacterial survival and replication in macrophages, and decreased bacterial dissemination in fish tissues. Our results also show that the expression of cadBA operon and regulator cadC were up-regulated upon acid stress, and CadC rigorously regulated the expression of cadBA operon, especially under acid conditions. These findings demonstrate that the AR CadBA system was a requisite for the resistance of E. tarda against acid stress, and played a critical role in bacterial infection of host cells and in host tissues. This is the first study about the acid resistance system of E. tarda and provides new insights into the acid-resistance mechanism and pathogenesis of E. tarda.
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Biopelículas , Edwardsiella tarda/fisiología , Edwardsiella tarda/patogenicidad , Factores de Virulencia/genética , Ácidos/metabolismo , Edwardsiella tarda/genéticaRESUMEN
Guiding institutional investors to actively participate in corporate governance is a hot issue to improve the internal governance of China's listed companies. This study seeks to provide a comprehensive understanding of the mechanism that underlies the governance effects of the heterogeneity of institutional investors on the cost of capital, and the influence of ownership structure on the relationship between them. Using an unbalanced panel data on A-share listed companies of Shanghai and Shenzhen in China's capital market during the 2014-2019 period, this study reveals how institutional investors with longer holding period and higher shareholding ratio are negatively associated with the cost of capital in China's capital market. Furthermore, this study successfully confirms the moderating effect of ownership structure in the relationship between institutional investors and the cost of capital. China's state-owned enterprises are more likely to introduce improvements at the corporate governance level, and ownership concentration weakens the negative influence of institutional investors on the cost of capital. The research contributes to a deeper understanding of the impacts of institutional investor's heterogeneity and ownership structure on the cost of capital in China. In the process, the study yields useful implications for the theory and practice of corporate governance.
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Inversiones en Salud/organización & administración , Propiedad/economía , China , Gobierno , Propiedad/organización & administraciónRESUMEN
Traditional architecture has been successful in achieving harmony between housing and environment, which is one of the most important conditions for sustainability. The research tried to study and analyze the traditional architecture to diagnose its importance and ability to solve contemporary problems. Firstly, this study sets up qualitative survey, including location, function space, and structural materials of the dwelling. Then typical dwellings were selected for the assessments of their indoor thermal environment by on-site monitoring. Quantitative analysis reveals that the earth wall has a "warm in winter and cool in summer" property. Secondly, from the perspective of user willingness, we propose the impact factors of dwelling's development. Finally, it puts forward the measures of dwelling's sustainable development and seeks to establish a strategy to guide the construction of new dwellings.
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Materiales de Construcción , Vivienda , China , Vivienda/tendencias , Humanos , Desarrollo SostenibleRESUMEN
OBJECTIVE: To study the effects of thyrotropin-releasing hormone (TRH) in combination with hypertonic saline/dextran (7.5% NaCl + 6% Dextran 40, HSD ) on hemorrhagic shock with pulmonary edema in the rats which were recently brought to high altitude. METHODS: Forty-nine SD rats, transported to Lasa, Tibet, which was 3,760 meters above the sea level, were anesthetized one week later with sodium pentobarbital (30 mg/kg, intraperitoneal). Hemorrhagic shock with pulmonary edema was induced by hemorrhage (50 mm Hg maintained for 1 hour,1 mm Hg=0.133 kPa) plus intravenous injection of oleic acid (50 microl/kg). They were equally divided into seven groups (n=7): normal control, hemorrhagic shock, hemorrhagic shock with pulmonary edema (HSPE), HSPE plus TRH (5 mg/kg), HSPE plus HSD (4 ml/kg), and HEPE plus TRH and HSD in combination. Hemodynamic parameters including mean arterial blood pressure(MAP), left intraventricular systolic pressure (LVSP) and the maximal change rate of intraventricular pressure rise or decline (+/- dp/dt max) were observed at 15, 30, 60 and 120 minutes, blood gases were analyzed at 30 and 120 minutes, and the water content of lung and brain was determined at 120 minutes after drug administration. RESULTS: TRH or HSD used alone or in combination significantly increased MAP, LVSP and +/- dp/dt max (P<0.05 or P<0.01 ), ameliorated acid-base imbalance, and decreased the water content of lung and brain. The effect of the two in combination was superior to either drug used alone. CONCLUSION: TRH in combination with HSD can be used in the treatment of hemorrhagic shock with pulmonary edema at high altitude.
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Altitud , Edema Pulmonar/tratamiento farmacológico , Solución Salina Hipertónica/uso terapéutico , Choque Hemorrágico/tratamiento farmacológico , Hormona Liberadora de Tirotropina/uso terapéutico , Animales , Edema Pulmonar/complicaciones , Ratas , Ratas Sprague-Dawley , Solución Salina Hipertónica/administración & dosificación , Choque Hemorrágico/complicaciones , Hormona Liberadora de Tirotropina/administración & dosificaciónRESUMEN
OBJECTIVE: To study the effects of different volumes of fluid resuscitation on hemorrhagic shock with pulmonary edema at high altitude in the unacclimated rat. METHODS: One hundred and twenty-six SD rats transported to Lasa, Tibet, 3 760 meters above the sea level, were anesthetized one week later with sodium pentobarbital (30 mg/kg, intraperitoneal). Hemorrhagic shock with pulmonary edema model was induced by hemorrhage (50 mm Hg for 1 hour, 1 mmHg=0.133 kPa) plus intravenous injection of oleic acid (50 microl/kg). Experiments were then conducted in two parts. Sixty-three rats in part I were equally divided into nine groups (n=7): normal control, hemorrhagic shock control, hemorrhagic shock with pulmonary edema (HSPE) without fluid infusion, HSPE plus infusing lactated Ringer's solution (LR) with 0.5-, 1-, 1.5-, 2- or 3- fold volume shed blood, and 1 volume of LR plus mannitol (10 ml/kg). Hemodynamic parameters including mean arterial blood pressure (MAP), left intraventricular systolic pressure (LVSP) and the maximal change rate of intraventricular pressure rise or decline (+/- dp/dt max) were observed at 15, 30, 60 and 120 minutes after infusion, blood gases were measured at 30 and 120 minutes after infusion and the water content of lung and brain was determined at 120 minutes after infusion. In part II, additional 63 rats were used to observe the effect of different volumes of fluid resuscitation on survival time of HSPE rats. RESULTS: 0.5 volume of LR infusion significantly improved MAP, LVSP and +/- dp/dt max, prolonged the survival time of HSPE animals (all P<0.01), while it did not increase the water content of lung and brain and had no marked influence on blood gases. One volume of LR infusion slightly improved hemodynamic parameters, prolonged the survival time and increased the water content of lung. More than 1 volume of LR infusion including 1.5-, 2- and 3- fold volume LR deteriorated the hemodynamic parameters and decreased the survival time of shocked animal, meanwhile they apparently increased the water content of lung. One volume of LR plus mannitol (10 ml/kg) infusion did not improve the hemodynamic parameters and blood gases; also it did not decrease the water content of lung. CONCLUSION: The tolerance to fluid infusion for the unacclimated animal subjected to hemorrhagic shock with pulmonary edema at high altitude is significantly decreased. 0.5-1 volume of LR infusion appears to be beneficial effect on resuscitation at high altitude, while over 1 volume of LR infusion would aggravate pulmonary edema and exacerbate fluid resuscitation effect.