Corrigendum: The critical role of PARPs in regulating innate immune responses.

[This corrects the article DOI: 10.3389/fimmu.2021.712556.].

Evasion of Antiviral Innate Immunity by Porcine Reproductive and Respiratory Syndrome Virus.

Innate immunity is the front line for antiviral immune responses and bridges adaptive immunity against viral infections. However, various viruses have evolved many strategies to evade host innate immunity. A typical virus is the porcine reproductive and respiratory syndrome virus (PRRSV), one of the most globally devastating viruses threatening the swine industry worldwide. PRRSV engages several strategies to evade the porcine innate immune responses. This review focus on the underlying mechanisms employed by PRRSV to evade pattern recognition receptors signaling pathways, type I interferon (IFN-α/ß) receptor (IFNAR)-JAK-STAT signaling pathway, and interferon-stimulated genes. Deciphering the antiviral immune evasion mechanisms by PRRSV will enhance our understanding of PRRSV's pathogenesis and help us to develop more effective methods to control and eliminate PRRSV.

The Critical Role of PARPs in Regulating Innate Immune Responses.

Poly (adenosine diphosphate-ribose) polymerases (PARPs) are a family of proteins responsible for transferring ADP-ribose groups to target proteins to initiate the ADP-ribosylation, a highly conserved and fundamental post-translational modification in all organisms. PARPs play important roles in various cellular functions, including regulating chromatin structure, transcription, replication, recombination, and DNA repair. Several studies have recently converged on the widespread involvement of PARPs and ADP-Ribosylation reaction in mammalian innate immunity. Here, we provide an overview of the emerging roles of PARPs family and ADP-ribosylation in regulating the host's innate immune responses involved in cancers, pathogenic infections, and inflammations, which will help discover and design new molecular targets for cancers, pathogenic infections, and inflammations.

Evasion of host antiviral innate immunity by HSV-1, an update.

Herpes simplex virus type 1 (HSV-1) infection triggers a rapid induction of host innate immune responses. The type I interferon (IFN) signal pathway is a central aspect of host defense which induces a wide range of antiviral proteins to control infection of incoming pathogens. In some cases, viral invasion also induces DNA damage response, autophagy, endoplasmic reticulum stress, cytoplasmic stress granules and other innate immune responses, which in turn affect viral infection. However, HSV-1 has evolved multiple strategies to evade host innate responses and facilitate its infection. In this review, we summarize the most recent findings on the molecular mechanisms utilized by HSV-1 to counteract host antiviral innate immune responses with specific focus on the type I IFN signal pathway.

Mechanism of action of gypenosides on type 2 diabetes and non-alcoholic fatty liver disease in rats.

AIM: To explore the mechanism of action of gypenosides (GPs) on type 2 diabetes mellitus and non-alcoholic fatty liver disease (T2DM-NAFLD) in rats. METHODS: Sixty rats were randomly divided into a healthy group, an untreated disease model group and GP-treatment groups. The study involved the evaluation of biochemical parameters, including serum aspartate transaminase (AST), alanine transferase (ALT), blood glucose (BG), triglycerides (TG) and total cholesterol (TC). Additionally, the protective effect of the treatments were confirmed histopathologically and the expression of TNF-α and NF-κB in the rat liver was analyzed using immunohistochemistry. The expression of proliferator-activated receptor gamma (PPARγ) and cytochrome P450 (CYP450) 1A1 mRNA was determined by quantitative RT-PCR. RESULTS: GP treatments at oral doses of 200, 400, and 800 mg/kg per day significantly decreased the levels of serum AST and ALT (P<0.05, P<0.01), especially at the dose of 800 mg/kg per day. To a similar extent, GP at 800 mg/kg per day reduced the levels of BG (4.19±0.47, P<0.01), TG (80.08±10.05, P<0.01), TC (134.38±16.39, P<0.01) and serum insulin (42.01±5.04, P<0.01). The expression of TNF-α and NF-κB measured by immunohistochemistry was significantly reduced by GPs in a dose-dependent manner, and the expression of PPARγ and CYP4501A1 mRNA, as measured using quantitative real-time PCR, were significantly down-regulated by GPs. Moreover, GPs decreased the infiltration of liver fats and reversed the histopathological changes in a dose-dependent manner. CONCLUSION: This study suggests that GPs have a protective effect against T2DM-NAFLD by down-regulating the expression of TNF-α and NF-κB proteins, and PPARγ and CYP4501A1 mRNAs.

Fluorescent sensor for selective determination of copper ion based on N-acetyl-L-cysteine capped CdHgSe quantum dots.

Using N-acetyl-L-cysteine as a stabilizer, well water-dispersed, high-quality and stable CdHgSe quantum dots were facilely synthesized via a simple aqueous phase method. The as-prepared N-acetyl-L-cysteine capped CdHgSe quantum dots were thoroughly characterized by transmission electron microscopy, X-ray diffraction spectroscopy and FTIR. A fluorescent sensor for selective determination of copper ions was developed using N-acetyl-L-cysteine capped CdHgSe quantum dots as fluorescent probe. The fluorescence intensity of N-acetyl-L-cysteine capped CdHgSe quantum dots decreased when interacted with copper ions due to the formation of coordination complex and aggregates. The method possesses high selectivity and is not influenced by some potential interferences such as Ag(+), Zn(2+), Co(2+) and Ni(2+). Under the optimal conditions, the change of fluorescence intensity (ΔI) was linearly proportional to the concentration of copper ions in the range of 1.0×10(-9)-4.0×10(-7) mol L(-1), with a detection limit as low as 2.0×10(-10) mol L(-1) (S/N=3). The developed method had been successfully employed to determine Cu(2+) in shrimp and South-lake water samples, and the results were verified by atomic absorption spectroscopy. The fluorescent sensor was demonstrated to be selective, sensitive and simple for copper ion determination, and promise for practical applications.

Facile synthesis of N-acetyl-L-cysteine capped CdHgSe quantum dots and selective determination of hemoglobin.

Using N-acetyl-L-cysteine (NAC) as a stabilizer, well water-dispersed, high-quality and stable CdHgSe quantum dots were facilely synthesized via a simple aqueous phase method. The as-prepared NAC capped CdHgSe quantum dots were thoroughly characterized by fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. A novel method for the selective determination of hemoglobin (Hb) was developed based on fluorescence quenching of the NAC capped CdHgSe quantum dots. A number of key factors including pH value of phosphate buffer solution, quantum dots concentration, the adding sequence of reagents and reaction time that influence the analytical performance of the NAC capped CdHgSe quantum dots in Hb determination were investigated. Under the optimal experimental conditions, the change of fluorescence intensity (ΔI) was linearly proportional to the concentration of Hb in the range of 4.0×10(-9)-4.4×10(-7) mol L(-1) with a detection limit of 2.0×10(-9) mol L(-1). The developed method has been successfully employed to determine Hb in human urine samples.

Sensitive amperometric biosensor for phenolic compounds based on graphene-silk peptide/tyrosinase composite nanointerface.

New graphene-silk peptide (Gr-SP) nanosheets were prepared and successfully fabricated with tyrosinase (Tyr) as a novel biosensor for the determination of phenolic compounds. The Gr-SP nanosheets were fully characterized with transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV/Vis and FTIR spectra. The developed biosensors were also characterized with scanning electronic microscopy and electrochemical impedance spectroscopy. Using bisphenol A (BPA) as a model substrate in the sensing system, a number of key factors including the volume of Gr-SP-Tyr solution, the applied potential, pH values, temperature, and the Tyr/Gr-SP ratio that influence the analytical performance of the biosensor were investigated. The biosensor gave a linear response on the concentration ranges of 0.001-16.91 µM for catechol with the sensitivity of 7634 mA M(-1)cm(-2), 0.0015-21.12 µM for phenol with the sensitivity of 4082 mA M(-1)cm(-2), and 0.002-5.48 µM for BPA with the sensitivity of 2511 mA M(-1)cm(-2). The low detection limits were estimated to be 0.23, 0.35 and 0.72 nM (S/N=3) for catechol, phenol and BPA, respectively. The biosensors also exhibit good repeatability and long-term stability. The practical application of the biosensor was also demonstrated by the determination of BPA leaching from commercial plastic drinking bottles.

Direct electron transfer of hemoglobin in a biocompatible electrochemical system based on zirconium dioxide nanotubes and ionic liquid.

Highly-ordered zirconium dioxide (ZrO(2)) nanotubes were prepared with porous anodic alumina as the template by the liquid phase deposition technique. The obtained ZrO(2) nanotubes were characterized by transmission electron micrograph (TEM) and X-ray diffraction (XRD). A new biocompatible nano-platform for the immobilization of hemoglobin (Hb) was developed by coating a chitosan (CHI) solution, in which the ZrO(2) nanotubes, 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid ([BMIM]BF(4)) and Hb were dispersed, onto a glassy carbon electrode surface. Direct electrochemistry of the immobilized Hb on the electrode surface was then investigated. The results indicated that remarkable improvements on the direct electrochemistry of Hb were achieved. In addition, the potential application of the Hb immobilized electrode (Hb/ZrO(2)/[BMIM]BF(4)/CHI/GCE) in biosensing was demonstrated by the catalytic electrochemical reduction of nitrite ion (NO(2)(-)) in an aqueous solution.

Preparation of parathion imprinted polymer beads and its applications in electrochemical sensing.

Parathion imprinted polymer beads were prepared by free radical polymerization using parathion as template, methacrylic acid as functional monomer, divinyl benzene as cross-linking reagent and 2,2'-azobis(isobutyronitrile) as initiator. The obtained molecularly imprinted beads were characterized with transmission electron micrograph. The rebinding properties of these imprinted beads towards parathion were studied by saturation binding experiments using ultraviolet/visible spectroscopy. Effects of the template, functional monomer, cross-linking reagent and initiator on selective adsorption of parathion were investigated. The high selectivity of the imprinted beads was successfully demonstrated by their selective adsorption of free parathion from an ethanol-water (v/v=1:5) solution. In addition, the parathion imprinted beads were dispersed into dihexadecyl hydrogen phosphate solution at the concentration of 1.0 mg mL(-1). By coating this solution onto a glassy carbon electrode surface, a molecularly imprinted electrochemical sensor for parathion was obtained. The electrochemical sensor exhibited good selectivity and fast response to parathion. Under optimized experimental conditions, the peak currents were found linearly proportional to the parathion concentration in the range of 1.0×10(-7) mol L(-1) to 1.0×10(-5) mol L(-1) with a detection limit of 5.4×10(-8) mol L(-1) (S/N=3). The developed sensor was successfully employed for the determination of parathion in pear juice samples.

Ultrasensitive determination of serum albumin using resonance light scattering based on ZnS-polyacrylic acid nanoparticles.

ZnS-polyacrylic acid (ZnS-PAA) was prepared by an in situ polymerization method using nano-ZnS as core in the presence of acrylic acid (AA), and ZnS-PAA nanoparticles was characterized by ultraviolet spectrometry (UV) and transmission electron microscopy (TEM). Based on the significant increase of the resonance light scattering (RLS) intensity with the interaction between nanoparticles and serum albumin, RLS method was developed for the sensitive determination of serum albumin (BSA and HSA). Under optimum conditions, the change of the intensity (DeltaI) of the RLS spectra at lambda=392nm was linearly proportional to the concentration of BSA and HSA. The linear range was 1-100ngmL(-1) for HSA and 1-120ngmL(-1) for BSA, and the limit of detection (LOD) was 0.4ngmL(-1) for HSA and 0.5ngmL(-1) for BSA. This method proved to be very sensitive, rapid, simple and tolerant of most interfering substances.

Electrochemical investigation of tryptophan at gold nanoparticles modified electrode in the presence of sodium dodecylbenzene sulfonate.

Glassy carbon electrode modified with gold nanoparticles was prepared using electrodeposition at constant potential of -0.20V, and characterized with scanning electron microscopy and electrochemical techniques. Voltammetry was employed to study the electrochemical behaviors of tryptophan at the Au nanoparticles modified electrode in the presence of sodium dodecylbenzene sulfonate. The results showed that the Au nanoparticles modified electrode had good performance for the electrochemical oxidation of tryptophan. Compared with the unmodified electrode, the Au nanoparticles modified electrode improved the adsorption of tryptophan on the nanointerface and amplified its current response. The oxidation peak potential showed a negative shift of 50mV in the presence of sodium dodecylbenzene sulfonate indicating that the electron transfer between the electrode and bulk solution of tryptophan was facilitated. Experimental parameters for tryptophan determination, such as deposition time, pH value, and accumulation conditions have been optimized. The oxidation peak current was linearly dependent on the tryptophan concentration and a calibration curve was obtained in the concentration range of 9.0x10(-8)molL(-1) to 5.0x10(-5)molL(-1) with detection limit of 8.0x10(-8)molL(-1) (S/N=3).

Resonance light scattering spectral method for the determination of serum albumin with the interaction of neutral red-sodium dodecyl sulfonate.

Based on the enhancement of resonance light scattering (RLS) of serum albumin interaction with neutral red (NR) and sodium dodecyl sulfonate (SDS), a novel sensitive assay of serum albumins has been developed. Experimental conditions such as mixing sequence of reagents, pH, NR and SDS concentrations have been optimized. Linear relationships between the enhanced RLS intensity and the protein concentration were observed for bovine serum albumin (BSA) within the range of 0.01-5.0 microg mL(-1) and human serum albumin (HAS) of 0.01-7.0 microg mL(-1). The detection limits (S/N=3) are 6.0 ng mL(-1) for BSA and 5.0 ng mL(-1) for HAS, respectively. The method was successfully applied to the determination of HSA in human blood plasma samples with recovery from 97.3 to 104.3%.

Analysis of fatty acids in lung tissues using gas chromatography-mass spectrometry preceded by derivatization-solid-phase microextraction with a novel fiber.

In this article, a laboratory-made sol-gel derived fiber with butyl methacrylate/hydroxy-terminated silicone oil (BMA/OH-TSO) coating was first used for headspace solid-phase microextraction (HS-SPME) of medium and long chain fatty acids after derivatization and applied to the analysis of fatty acids in lung tissues by coupling to gas chromatography-mass spectrometry (GC-MS). The experimental parameters for derivatization, HS-SPME and desorption were optimized. Fatty acids in cancerous lung tissues from five patients with lung cancer were determined under the optimized conditions. Normal lung tissues from the same five patients were used as controls. This fiber showed higher extraction efficiency for fatty acids after derivatization when compared with commercial polydimethylsiloxane (PDMS) and polydimethylsiloxane-divinylbenzene (PDMS/DVB) fibers due to the three-dimensional network in the coating. The method presented in this paper showed satisfactory precision, accuracy, linearity and limits of detection (LODs). The relative standard deviation values were below 13.3% (n=5) and the recoveries obtained ranged from 76.35% to 107.0%. The results obtained using the SPME method were also compared with those got by using liquid-liquid extraction (LLE) technique. It was found that the sensitivity could be enhanced by the SPME method. The analysis of the cancerous lung tissues and normal controls from five patients with lung cancer indicated that the main components of lung tissue were palmitic acid (C16:0), stearic acid (C18:0) and lignoceric acid (C24:0). A comparison between the levels of the fatty acids in cancerous lung tissues and normal controls from the same a patient with lung cancer shows that most of the saturated fatty acids showed higher levels in cancerous lung tissues, while unsaturated fatty acids showed higher levels in normal controls on the whole.