Retinoic acid-inducible gene I (RIG-I) is a pattern recognition receptor and is involved in the innate immune response against RNA viruses infection. Here, we demonstrate that the ...Ras-GTPase-activating protein SH3-domain-binding protein 1 (G3BP1) serves as a positive regulator of the RIG-I-mediated signaling pathway. G3BP1-deficient cells inhibited RNA virus-triggered induction of downstream antiviral genes. Furthermore, we found that G3BP1 inhibited the replication of Sendai virus and vesicular stomatitis virus, indicating a positive regulation of G3BP1 to cellular antiviral responses. Mechanistically, G3BP1 formed a complex with RNF125 and RIG-I, leading to decreased RNF125 via its auto-ubiquitination; thus, promoting expression of RIG-I. Overall, the results suggest a novel mechanism for G3BP1 in the positive regulation of antiviral signaling mediated by RIG-I.
TANK-binding kinase 1 (TBK1) is essential for interferon beta (IFN-β) production and innate antiviral immunity. However, other, additional functions of TBK1 have remained elusive. Here, we showed ...that TBK1 is an E3 ubiquitin ligase that undergoes self-ubiquitylation
in the presence of the E2 enzyme UbcH5c. Further evidence showed that TBK1 could also be self-ubiquitylated
Importantly, multiple picornavirus VP3 proteins were degraded by TBK1 through its kinase and E3 ubiquitin ligase activity. Mechanistically, TBK1 phosphorylated multiple picornavirus VP3 proteins at serine residues and ubiquitinated them via K63-linked ubiquitination at lysine residues. In addition, the C426 and C605 residues of TBK1 were not essential for TBK1 innate immunity activity; however, these residues were required for degradation of multiple picornavirus VP3 proteins and for its E3 ubiquitin ligase activity. Hence, our findings identified a novel role of TBK1 in regulating the virus life cycle and provided new insights into the molecular mechanisms of TBK1-mediated antiviral response.
TBK1 is an important adaptor protein required for innate immune response to viruses, but its other functions were unknown. In this study, we found that TBK1 is an E3 ubiquitin ligase that undergoes self-ubiquitylation
in the presence of the E2 enzyme UbcH5c. In addition, multiple picornavirus VP3 proteins were degraded by TBK1 through its kinase and E3 ubiquitin ligase activity. Our report provides evidence that TBK1 plays a role in viral protein degradation.
The integration of HIV-1 DNA into the host genome results in single-strand gaps and 2-nt overhangs at the ends of viral DNA, which must be repaired by cellular enzymes. The cellular factors ...responsible for the DNA damage repair in HIV-1 DNA integration have not yet been well defined. We report here that HIV-1 infection potently activates the Fanconi anemia (FA) DNA repair pathway, and the FA effector proteins FANCI-D2 bind to the C-terminal domain of HIV-1 integrase. Knockout of FANCI blocks productive viral DNA integration and inhibits the replication of HIV-1. Finally, we show that the knockout of DNA polymerases or flap nuclease downstream of FANCI-D2 reduces the levels of integrated HIV-1 DNA, suggesting these enzymes may be responsible for the repair of DNA damages induced by viral DNA integration. These experiments reveal that HIV-1 exploits the FA pathway for the stable integration of viral DNA into host genome.
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•HIV-1 infection activates the Fanconi anemia (FA) DNA repair pathway•HIV-1 integrase interacts with FANCI-D2 complex•Depletion of FA proteins and downstream enzymes inhibits HIV-1 DNA integration
Fu et al. show that HIV-1 integrase interacts with FANCI-D2 complex, and HIV-1 DNA integration activates the Fanconi anemia (FA) pathway. They discover that the depletion of FA proteins and downstream enzymes blocks viral DNA integration, suggesting that the FA pathway is exploited by HIV-1 to repair DNA damage induced by viral DNA integration.
Foot-and-mouth disease virus (FMDV) causes a highly contagious and debilitating disease in cloven-hoofed animals, which leads to devastating economic consequences. Previous studies have reported that ...some FMDV proteins can interact with host proteins to affect FMDV replication. However, the influence of the interactions between FMDV VP0 protein and its partners on FMDV replication remains unknown. In this study, we found that the overexpression of poly (rC) binding protein 2 (PCBP2) promoted FMDV replication, whereas the knockdown of PCBP2 suppressed FMDV replication. Furthermore, PCBP2 can interact with FMDV VP0 protein to promote the degradation of VISA via the apoptotic pathway. Further studies demonstrated that FMDV VP0 protein enhanced the formation of the PCBP2-VISA complex. Ultimately, we found that the degradation of VISA was weaker in PCBP2-knockdown and FMDV VP0-overexpressing cells, or FMDV VP0-knockdown cells than in the control cells. Summarily, our data revealed that the interaction between PCBP2 and VP0 could promote FMDV replication via the apoptotic pathway.
Residual doxycycline (DOX) in the aquatic environment has received a considerable amount of critical attention due to its toxicity and widespread distribution in the environment. This study explored ...a simplified and rapid method to remove DOX over a wide pH range (pH = 2–10). Schwertmannite (SCH) was synthesized using biological methods to remove DOX in combination with H2O2. The results showed that 98.52% of DOX and 57.35% of total organic carbon (TOC) was removed over 30 min at 50 ºC without any external energy input, where the addition of SCH and H2O2 was 1.6 g/L and 71 mg/L, respectively. Meanwhile, the DOX removal efficiency was 98.18% at 50 ºC over 30 min and 97.70% of DOX could even be removed at 10 ºC when the reaction time was prolonged to 120 min. Hydroxyl radicals (·OH) were the main oxidative species. Moreover, the removal efficiencies of DOX after 3 h in the SCH/H2O2 system were 26.97%, 31.54%, 39.23%, 47.07%, 68.43%, 88.92%, and 97.64% in actual aquaculture wastewater when the COD concentrations was 7000, 5000, 3000, 1000, 500, 200, and 100 mg/L, respectively. The results of this study provided a simple and rapid method for removing DOX from DOX-containing wastewater.
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•Schwertmannite is used as a Fenton-like catalyst for doxycycline(DOX) removal.•The DOX degradation system works well in a wide pH range 2–10.•The DOX removal process has a strong temperature adaptability in 10 ºC–50 ºC.•The Fenton-like system has a good removal effect on DOX in actual wastewater.
BACKGROUND: This paper describes the reuse of paper sludge, an industrial solid waste, for the preparation of sodium carboxymethyl cellulose (CMC). The process includes pretreatment, basification and ...etherification.RESULTS: The optimal pretreatment condition involved the addition of 6.7% hydrochloric acid to the paper sludge for 30 min at 70 °C. The order of factors influencing the effect of reaction was: etherification temperature > sodium hydroxide dose > basification temperature > etherification time > sodium chloroacetate dose. The optimal preparation condition of CMC was: mpapersludge: msodiumhydroxide: msodiumchloroacetate = 0.9:0.8:1.15; basification at 40 °C; etherification at 60 °C for 1 h. Under these conditions, certified CMC with viscosity less than 20 mPa· s, DS more than 0.50 and purity more than 90% was produced. The results of Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectra analyses indicated that the product has characteristics of high degree of substitution (DS) and low crystallinity. The coated paper using CMC prepared from paper sludge as a water retention agent can meet the quality standards of GB/T 10335.1-2005.CONCLUSION: Preparation of CMC from paper sludge can be considered a feasible alternative, generating value-added product and contributing to solving environmental problems resulting from paper sludge. Copyright
Two types of dispersants for calcium carbonate were synthesized by condensation polymerization. One was the acrylic homopolymer (Dispersant-A), and the other was copolymer of acrylic acid with ...unsaturated esters (Dispersant-B). For the former, the optimal synthesizing parameters were determined: ammonium persulfate of 4.0% as the initiator; isopropanol/water of 1.25 as the chain-transfer, and sodium hydroxide as the neutralization agent. For the latter, the proper weight ratio of unsaturated ester/acrylic acid was found to be 1:4. Comparison was made between the dispersants and the popular products such as Acumer9400 synthesized in US, SP40M produced in Taipei, and SN5040 from Japan. Dispersion experiments for 3000-mesh calcium carbonate showed that Dispersant-B had the highest dispersing capability of the four dispersants. The dispersing capability of Dispersant-A was close to that of Acumer9400, but higher than that of SP40M at the dosage range of 1.2–2.0‰. Dispersant-B and SN5040 were the suitable dispersants for the dispersion of nanometer calcium carbonate. The grinding experiment of 325-mesh calcium carbonate revealed a logarithmic relation between the weight percentage of fine particles and the cumulative specific energy input. Moreover, a power-low function was well established between the median size and the cumulative specific energy input.
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