The D129L protein of African swine fever virus interferes with the binding of transcriptional coactivator p300 and IRF3 to prevent beta interferon induction.

IMPORTANCE: African swine fever (ASF) is an acute, hemorrhagic, and severe porcine infectious disease caused by African swine fever virus (ASFV). ASF outbreaks severely threaten the global pig industries and result in serious economic losses. No safe and efficacious commercial vaccine is currently available except in Vietnam. To date, large gaps in the knowledge concerning viral biological characteristics and immunoevasion strategies have hindered the ASF vaccine design. In this study, we demonstrate that pD129L negatively regulates the type I interferon (IFN) signaling pathway by interfering with the interaction of the transcriptional coactivator p300 and IRF3, thereby inhibiting the induction of type I IFNs. This study reveals a novel immunoevasion strategy employed by ASFV, shedding new light on the intricate mechanisms for ASFV to evade the host immune responses.

Phosphatidic acid regulates ammonium uptake by interacting with AMMONIUM TRANSPORTER 1;1 in Arabidopsis.

Ammonium (NH4+) is a key inorganic nitrogen source in cellular amino acid biosynthesis. The coupling of transcriptional and posttranslational regulation of AMMONIUM TRANSPORTER (AMT) ensures that NH4+ acquisition by plant roots is properly balanced, which allows for rapid adaptation to a variety of nitrogen conditions. Here, we report that phospholipase D (PLD)-derived phosphatidic acid (PA) interacts with AMT1;1 to mediate NH4+ uptake in Arabidopsis (Arabidopsis thaliana). We examined pldα1 pldδ-knockout mutants and found that a reduced PA level increased seedling growth under nitrogen deficiency and inhibited root growth upon NH4+ stress, which was consistent with the enhanced accumulation of cellular NH4+. PA directly bound to AMT1;1 and inhibited its transport activity. Mutation of AMT1;1 R487 to Gly (R487G) resulted in abolition of PA suppression and, subsequently, enhancement of ammonium transport activity in vitro and in vivo. Observations of AMT1;1-GFP showed suppressed endocytosis under PLD deficiency or by mutation of the PA-binding site in AMT1;1. Endocytosis was rescued by PA in the pldα1 pldδ mutant but not in the mutant AMT1;1R487G-GFP line. Together, these findings demonstrated PA-based shutoff control of plant NH4+ transport and point to a broader paradigm of lipid-transporter function.

Identification and target of action of cholecystokinin-releasing peptides from simulated digestion hydrolysate of wheat protein.

BACKGROUND: Wheat protein intake leads to improved appetite control. However, the active components causing appetite in wheat have not been fully clarified. Gut cholecystokinin (CCK) plays a vital role in appetite control. This study aimed to investigate the ability of wheat protein digest (WPD) to stimulate CCK secretion and clarify the active components and target of action. RESULTS: WPD was prepared by a simulated gastrointestinal digestion model. WPD treatment with a concentration of 5 mg mL-1 significantly stimulated CCK secretion in enteroendocrine STC-1 cells (P < 0.05). Furthermore, oral gavage with WPD in mice significantly increased plasma CCK level at 60 min (P < 0.01). Preparative C18 column separation was used to isolate peptide fractions associated with CCK secretion and peptide sequences were identified by liquid chromatography-tandem mass spectrometry. A new CCK-releasing peptide, RYIVPL, that potently stimulated CCK secretion was successfully identified. After pretreatment with a specific calcium-sensing receptor (CaSR) antagonist, NPS 2143, CCK secretion induced by WPD or RYIVPL was greatly suppressed, suggesting that CaSR was involved in WPD- or RYIVPL-induced CCK secretion. CONCLUSION: The present study demonstrated that WPD has an ability to stimulate CCK secretion in vitro and in vivo, and determined that peptide RYIVPL in WPD could stimulate CCK secretion through CaSR. © 2023 Society of Chemical Industry.

Health benefits of saponins and its mechanisms: perspectives from absorption, metabolism, and interaction with gut.

Saponins, consisting of sapogenins as their aglycones and carbohydrate chains, are widely found in plants and some marine organisms. Due to the complexity of the structure of saponins, involving different types of sapogenins and sugar moieties, investigation of their absorption and metabolism is limited, which further hinders the explanation of their bioactivities. Large molecular weight and complex structures limit the direct absorption of saponins rendering their low bioavailability. As such, their major modes of action may be due to interaction with the gastrointestinal environment, such as enzymes and nutrients, and interaction with the gut microbiota. Many studies have reported the interaction between saponins and gut microbiota, that is, the effects of saponins on changing the composition of gut microbiota, and gut microbiota playing an indispensable role in the biotransformation of saponins into sapogenins. However, the metabolic routes of saponins by gut microbiota and their mutual interactions are still sparse. Thus, this review summarizes the chemistry, absorption, and metabolic pathways of saponins, as well as their interactions with gut microbiota and impacts on gut health, to better understand how saponins exert their health-promoting functions.

Meta-Analysis of the Prevalence of Giardia duodenalis in Cattle in China.

Giardia duodenum (G. duodenalis) can cause giardiasis and infect a variety of hosts. So far, there have been no detailed data regarding the positive rate of G. duodenalis in cattle in China. Here, a systematic literature review was carried out to investigate the epidemiology of bovine G. duodenalis in China. To perform the meta-analysis, the databases China National Knowledge Infrastructure, VIP Chinese Journal Databases, WanFang Databases, PubMed, and ScienceDirect were employed for screening studies related to the prevalence of G. duodenalis in cattle in China. The total prevalence of G. duodenalis in cattle was estimated to be 8.00% (95% confidence interval [CI]: 5.51-11.62). In the age subgroup, the prevalence of G. duodenalis in calves (11.72%; 95% CI: 7.75-17.73) was significantly higher than that in cattle of other age groups. An analysis based on seasons showed that the prevalence of G. duodenalis in cattle was higher in summer (9.69%; 95% CI: 2.66-35.30) than that in other seasons. The prevalence of G. duodenalis in cattle in 2016 or later was 11.62% (95% CI: 6.49-20.79), which was significantly higher than that before 2016 (3.65%; 95% CI: 2.17-6.12). The highest prevalence of G. duodenalis in cattle was 74.23% (95% CI: 69.76-78.45) recorded in South China. The NOAA's National Center for Environmental Information (https://gis.ncdc.noaa.gov/maps/ncei/cdo/monthly) was used to extract relevant geoclimatic data (latitude, longitude, elevation, temperature, precipitation, humidity, and climate). By analyzing the data of each subgroup, it was shown that age of cattle, sampling year, province, region, temperature, and climate were potential risk factors for giardiasis prevalence in cattle. Based on the analysis of common factors and geographical factors, it is recommended to strengthen effective management measures (e.g., ventilation and disinfection in warm and humid areas) and formulate relevant policies according to local conditions. Breeders should pay more attention to the detection of G. duodenalis in calves, to prevent giardiasis prevalence in cattle of different ages, thereby reducing the economic losses of animal husbandry in China.

In vitro gastrointestinal digestion of highland barley protein: identification and characterization of novel bioactive peptides involved in gut cholecystokinin secretion.

BACKGROUND: The satiety hormone cholecystokinin (CCK) plays an important role in food intake inhibition. Its secretion is regulated by dietary components. The search for bioactive compounds that induce CCK secretion is currently an active area of research. The objective of this study was to evaluate the ability of highland barley protein digest (HBPD) to stimulate CCK secretion in vitro and in vivo and identify the responsible peptide sequences. RESULTS: HBPD was prepared by in vitro gastrointestinal digestion model. Peptides of <1000 Da in HBPD accounted for 82%. HBPD was rich in essential amino acids Leu, Phe and Val, but lack in sulfur amino acids Met and Cys. HBPD treatment at a concentration of 5 mg mL-1 significantly stimulated CCK secretion from enteroendocrine STC-1 cells (P < 0.05). Moreover, oral gavage with HBPD in mice significantly increased plasma CCK level. Chromatographic separation was performed to isolate peptide fractions involved in CCK secretion and peptide sequence was determined by ultra-performance liquid chromatography-tandem mass spectrometry. Two novel CCK-releasing peptides, PDLP and YRIVPL, were pointed out for their outstanding CCK secretagogue activity. CONCLUSION: This study demonstrated for the first time that HBPD had an ability to stimulate CCK secretion in vitro and in vivo and determined the bioactive peptides exerting CCK secretagogue activity in HBPD. © 2023 Society of Chemical Industry.

Synergistic improvement of quinoa protein heat-induced gel properties treated by high-intensity ultrasound combined with transglutaminase.

BACKGROUND: Quinoa protein is enriched with a wide range of amino acids, including all nine essential amino acids necessary for the human body, and in appropriate proportions. However, as the main ingredient of gluten-free food, it is difficult for quinoa to form a certain network structure for lack of gluten protein. The aim of this work was to enhance the gel properties of quinoa protein. Therefore, the texture characteristics of quinoa protein treated with different ultrasound intensities coupled with transglutaminase (TGase) were investigated. RESULTS: The gel strength of quinoa protein gel increased markedly by 94.12% with 600 W ultrasonic treatment, and the water holding capacity increased from 56.6% to 68.33%. The gel solubility was reduced and free amino content increased the apparent viscosity and the consistency index. Changes in the free sulfhydryl group and hydrophobicity indicated that ultrasound stretched protein molecules and exposed active sites. The enhanced intrinsic fluorescence intensity at 600 W demonstrated that ultrasonic treatment affected the conformation of quinoa protein. New bands emerged in sodium dodecylsulfate-polyacrylamide gel electrophoresis indicating that high-molecular-weight polymers were generated through TGase-mediated isopeptide bonds. Furthermore, scanning electron microscopy showed that the gel network structure of TGase-catalyzed quinoa protein was more uniform and denser, thereby improving the gel quality of quinoa protein. CONCLUSION: The results suggested that high-intensity ultrasound combined with TGase would be an effective way to develop higher-quality quinoa protein gel. © 2023 Society of Chemical Industry.

Mechanistic insights into the changes of enzyme activity in food processing under microwave irradiation.

Microwave (MW) and enzyme catalysis are two emerging processing tools in the field of food industry. Recently, MW has been widely utilized as a novel type of green and safe heating energy. However, the effect of MW irradiation on enzyme activity is not described clearly. The intrinsic mechanisms behind enzyme activation and inactivation remain obscure. To apply better MW to the field of enzyme catalysis, it is essential to gain insights into the mechanism of MW action on enzyme activity. This review summarizes the changes in various enzyme activity during food processing, especially under MW irradiation. The intrinsic mechanism of thermal and nonthermal effects of MW irradiation was analyzed from the perspective of enzyme reaction kinetics and spatial structure. MW irradiation temperature is a vital parameter affecting the catalytic activity of enzymes. Activation of the enzyme activity is achieved even at high MW power when the enzyme is operating at its optimum temperature. However, when the temperature exceeds the optimum temperature, the enzyme activity is inhibited. In addition to MW dielectric heating effect, nonthermal MW effects also alter the microenvironment of reactive system. Taken together, enzyme activity is influenced by both thermal and nonthermal MW effects.

Comparative efficacy of novel antidiabetic drugs on cardiovascular and renal outcomes in patients with diabetic kidney disease: A systematic review and network meta-analysis.

AIMS: To conduct a systematic review and network meta-analysis to determine the comparative effectiveness of sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors in patients with diabetic kidney disease (DKD). METHODS: Phase III or IV randomized, placebo-controlled trials evaluating SGLT2 inhibitors, GLP-1RAs or DPP-4 inhibitors in patients with DKD were identified from the MEDLINE database. The outcomes of interest were a kidney-specific composite outcome, kidney disease progression, major adverse cardiovascular events (MACE), hospitalization for heart failure (HHF) and cardiovascular death. A network meta-analysis was conducted to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Sixteen trials representing a total of 46 292 patients were included. SGLT2 inhibitors significantly reduced the risk of the kidney-specific composite outcome by 26% compared to GLP-1RAs (HR 0.74, 95% CI 0.62-0.88) and by 36% compared to DPP-4 inhibitors (HR 0.64, 95% CI 0.52-0.79). The risk of MACE was significantly reduced with SGLT2 inhibitors (by 18%; HR 0.82, 95% CI 0.72-0.93), and with GLP-1RAs (by 18%; HR 0.82, 95% CI 0.69-0.96), compared to DPP-4 inhibitors. SGLT2 inhibitors significantly reduced the risk of HHF by 28% compared to GLP-1RAs (HR 0.72, 95% CI 0.56-0.92) and by 41% compared to DPP-4 inhibitors (HR 0.59, 95% CI 0.49-0.71). CONCLUSIONS: A clear advantage was demonstrated by SGLT2 inhibitors in reducing the risks of CV and renal events in patients with DKD, compared to GLP-1RAs and DPP-4 inhibitors. We recommend that SGLT2 inhibitors be considered the treatment of choice in patients with DKD.

Using noninvasive anthropometric indices to develop and validate a predictive model for metabolic syndrome in Chinese adults: a nationwide study.

PURPOSE: Metabolic syndrome (Mets) is a pathological condition that includes many abnormal metabolic components and requires a simple detection method for rapid use in a large population. The aim of the study was to develop a diagnostic model for Mets in a Chinese population with noninvasive anthropometric and demographic predictors. PATIENTS AND METHODS: Least absolute shrinkage and selection operator (LASSO) regression was used to screen predictors. A large sample from the China National Diabetes and Metabolic Disorders Survey (CNDMDS) was used to develop the model with logistic regression, and internal, internal-external and external validation were conducted to evaluate the model performance. A score calculator was developed to display the final model. RESULTS: We evaluated the discrimination and calibration of the model by receiver operator characteristic (ROC) curves and calibration curve analysis. The area under the ROC curves (AUCs) and the Brier score of the original model were 0.88 and 0.122, respectively. The mean AUCs and the mean Brier score of 10-fold cross validation were 0.879 and 0.122, respectively. The mean AUCs and the mean Brier score of internal-external validation were 0.878 and 0.121, respectively. The AUCs and Brier score of external validation were 0.862 and 0.133, respectively. CONCLUSIONS: The model developed in this study has good discrimination and calibration performance. Its stability was proved by internal validation, external validation and internal-external validation. Then, this model has been displayed by a calculator which can exhibit the specific predictive probability for easy use in Chinese population.

Microwaving released more polyphenols from black quinoa grains with hypoglycemic effects compared with traditional cooking methods.

BACKGROUND: Polyphenols were reported to exhibit inhibitory effects on digestive enzymes to regulate carbohydrates and lipid digestion. However, different cooking methods might cause differences in the composition of polyphenols in cereal grains and thus further affect their activities. RESULTS: The present study used boiling, roasting and microwaving to cook black quinoa and extracted polyphenols from them. Their total phenolic content (TPC) and total flavonoids content were determined, and phenolic composition was analyzed via high-performance liquid chromatography-mass spectrometry (HPLC-MS). Compared with other cooking methods, phenolic extract from microwaved black quinoa (PEM) showed the highest TPC value (about 2.64 mg GAE g-1 ). Microwaving released more phenolic acids (ferulic acid and gallic acid) from black quinoa grains. PEM also exhibited the strongest antioxidant and α-glucosidase inhibitory activities. Lineweaver-Burk plots showed that PEM inhibited α-glucosidase in an uncompetitive mode, which was supported by circular dichroism analysis. PEM further reduced about 20.04% of digested starch in an in vitro digestion model and suppressed postprandial blood glucose increases (about 16.91% reduction) in vivo. CONCLUSION: Collectively, our data suggested that microwaving could be an ideal method to cook quinoa in regards of its polyphenols in management of postprandial blood glucose. © 2022 Society of Chemical Industry.

Expression of the human or porcine C-type lectins DC-SIGN/L-SIGN confers susceptibility to porcine epidemic diarrhea virus entry and infection in otherwise refractory cell lines.

Porcine epidemic diarrhea virus (PEDV) is an alphacoronavirus that causes great economic losses in the porcine industry. Although the functional receptor for the virus has not been identified, multiple isolates are able to infect different cell lines. Recently, it has been shown that the human C-type lectin DC-SIGN/L-SIGN (hDC-SIGN/L-SIGN) can promote entry of several coronaviruses. Here we examined whether hDC-SIGN/L-SIGN and its porcine homolog (pDC-SIGN) are entry determinants for PEDV. Expression of hDC-SIGN/L-SIGN or pDC-SIGN in refractory cells dramatically increased infection by a recombinant PEDV expressing green fluorescent protein. In both cases, lectin-mediated infection was inhibited by mannan or anti-hDC-SIGN/L-SIGN or pDC-SIGN antibodies; however, d-galactose had no effect on the virus-infected cells. Our results demonstrate that hDC-SIGN/L-SIGN or pDC-SIGN can mediate the cellular entry and propagation of PEDV, which provides a new theoretical basis for further understanding the infection mechanism of PEDV, and will be helpful for the development of novel therapeutic agents.

Food-grade γ-aminobutyric acid production by immobilized glutamate decarboxylase from Lactobacillus plantarum in rice vinegar and monosodium glutamate system.

OBJECTIVES: γ-amino butyric acid (GABA) is a non-protein amino acid, considered a potent bioactive compound. This study focused on biosynthesis of food-grade GABA by immobilized glutamate decarboxylase (GAD) from Lactobacillus plantarum in the rice vinegar and monosodium glutamate (MSG) reaction system. RESULTS: The gene encoding glutamate decarboxylase (GadB) from L. plantarum has been heterologously expressed in Lactococcus lactis and biochemically characterized. Recombinant GadB existed as a homodimer, and displayed maximal activity at 40 °C and pH 5.0. The Km value and catalytic efficiency (kcat/Km) of GadB for L-Glu was 22.33 mM and 62.4 mM-1 min-1, respectively, with a specific activity of 24.97 U/mg protein. Then, purified GadB was encapsulated in gellan gum beads. Compared to the free enzyme, immobilized GadB showed higher operational and storage stability. Finally, 9.82 to 21.48 g/L of GABA have been acquired by regulating the amounts of catalyst microspheres ranging from 0.5 to 0.8 g (wet weight) in 0.8 mL of the designed rice vinegar and MSG reaction system. CONCLUSIONS: The method of production GABA by immobilized GadB microspheres mixed in the rice vinegar and MSG reaction system is introduced herein for the first time. Especially, the results obtained here meet the increased interest in the harnessing of biocatalyst to synthesize food-grade GABA.

Effect of lipase incorporation on gelling properties of catfish (Clarias lazera) surimi and its mechanism.

BACKGROUND: Recently, fatty fish have been utilized as a potential approach for the fabrication of surimi products, with the yield of fatty fish surimi being > 10 000 tons in 2019. However, the gelling properties of catfish surimi can be influenced by intermuscular lipid. Lipase could effectively enhance the gel quality of catfish surimi gels, although the chemical forces involved in gel formation and alteration in lipid and protein oxidation status are not well understood. The present study investigated the gelation-enhancing effects of lipase on catfish surimi based on changes in chemical oxidation interactions. RESULTS: The addition of 7.5 g kg-1 lipase significantly increased the hydrophobic interactions and disulfide bond contents, both of which facilitated gel formation, in surimi gels. The 2-thiobarbituric acid reactive substance and carbonyl concentrations demonstrated that lipase promoted lipid and protein oxidations. Furthermore, an appropriate dose of malondialdehyde accelerated protein oxidation, thereby resulting in the covalent cross-linking of proteins. Consequently, the gel strength increased from 55.72 to 127.71 g × cm with lipase contents of up to 7.5 g kg-1 , and strong chemical cross-linking and a compact network were observed via sodium dodecyl sulfate polyacrylamide gel electrophoresis and scanning electron microscopy. However, excessive oxidation led to the degeneration of the gel matrix. A schematic mechanism, mainly based on the chemical changes, is proposed. CONCLUSION: The present study revealed the gelation mechanism of catfish surimi gels with lipase, and suggested that lipase treatments may be an effective approach for improving the textural properties of fatty fish surimi gels. © 2021 Society of Chemical Industry.

Liver Plays a Major Role in FGF-21 Mediated Glucose Homeostasis.

BACKGROUND/AIMS: The liver is a vital organ in vertebrates and has a wide range of functions, including glucose absorption, glycogen storage and glucose production. Fibroblast growth factor (FGF)-21 is a metabolic regulator that is primarily produced by the liver. In this paper, we studied the effect of FGF-21 on glucose metabolism in the liver. METHODS: The glucose uptake of cells was detected by 2-Deoxy-d-[3H] glucose; the synergy between insulin and FGF-21 was evaluated. The mRNA expression of GLUT1-4, G6Pase and PEPCK was detected by real-time PCR. Glycogen synthesis was examined by the anthrone method. Blood samples to monitor glucose in db/db diabetic mice were obtained by tail snip. Glucose metabolism in the liver and adipose tissues was observed by fluorescence microscopy. RESULTS: In this study, FGF-21 stimulated glucose uptake by liver cells in both a dose and time-dependent manner, and at the same time, FGF-21 specifically stimulated GLUT1 expression in the liver cells. Furthermore, FGF-21 demonstrated a synergistic effect with insulin on glucose absorption, which is in accordance with enhanced GLUT-1 and -4 expression. Treatment with FGF-21 increased glycogen storage in liver cells. Consistent with in vitro results, FGF-21 lowered the plasma glucose level and stimulated GLUT1 expression and glycogen synthesis in db/db diabetic mice. Simultaneously, FGF-21 inhibited the gene expression of G6Pase and PEPCK. CONCLUSION: Our results suggest that FGF-21 clears up plasma glucose by stimulating glucose absorption in the liver of diabetic animals and decreases glucose release from the liver by inhibiting gluconeogenesis. Overall, these data indicate that the liver is an important target organ of FGF-21 to regulate glucose metabolism.

Comparative characterization analysis of synonymous codon usage bias in classical swine fever virus.

Classical swine fever virus (CSFV) is responsible for the highly contagious viral disease of swine, and causes great economic loss in the swine-raising industry. Considering the significance of CSFV, a systemic analysis was performed to study its codon usage patterns. In this study, using the complete genome sequences of 76 CSFV representing three genotypes, we firstly analyzed the relative nucleotide composition, effective number of codon (ENC) and synonymous codon usage in CSFV genomes. The results showed that CSFV is GC-moderate genome and the third-ended codons are not preferentially used. Every ENC values in CSFV genomes are >50, indicating that the codon usage bias is comparatively slight. Subsequently, we performed the correspondence analysis (COA) to investigate synonymous codon usage variation among all of the CSFV genomes. We found that codon usage bias in these CSFV genomes is greatly influenced by G + C mutation, which suggests that mutational pressure may be the main factor determining the codon usage biases. Moreover, most of the codon usage bias among different CSFV ORFs is directly related to the nucleotide composition. Other factors, such as hydrophobicity and aromaticity, also influence the codon usage variation among CSFV genomes. Our study represents the most comprehensive analysis of codon usage patterns in CSFV genome and provides a basic understanding of the mechanisms for its codon usage bias.

The nuclear protein Sam68 is recruited to the cytoplasmic stress granules during enterovirus 71 infection.

Our previous study found that the nuclear protein, 68-kDa Src-associated in mitosis protein (Sam68), is translocated to the cytoplasm and forms punctate pattern during enterovirus 71 (EV71) infection [Virus Research, 180 (2014), 1-11]. However, the exact function of this punctate pattern in cytoplasm during EV71 infection remains unknown. In this study, we firstly have examined this punctate pattern of Sam68 re-localization in the cytoplasm, and observed the obvious recruitments of Sam68 to the EV71-induced stress granules (SGs). Sam68, belongs to the KH domain family of RNA binding proteins (RBPs), was then confirmed that its KH domain was essential for this recruitment. Nevertheless, Knockdown of Sam68 expression using ShRNA had no effects on SGs assembly, indicating that Sam68 is not a constitutive component of the SGs during EV71 infection. Lastly, we investigated the importance of microtubulin transport to SGs aggregation, and revealed that microtubule depolymerization inhibited SGs formation, suggesting that EV71-induced SGs move throughout the cytoplasm in a microtubule-dependent manner. Taken together, these results illuminated that EV71 infections can induce SGs formation, and Sam68, as a SGs component, migrates alone with SGs dependent on intact microtubule upon the viral infections. These findings may provide novel underlying mechanism for delineating the role of SGs during EV71 infection.

Enterovirus 71 inhibits cellular type I interferon signaling by inhibiting host RIG-I ubiquitination.

Enterovirus 71 (EV71) is a human pathogen that induces hand, foot, and mouth disease (HFMD) and fatal neurological diseases in young children and infants. Pathogenicity of EV71 is likely related to its ability to evade host innate immunity through inhibiting cellular type I interferon signaling. However, it is less well understood the molecular events governing this process. In this study, we found that EV71 infection suppressed the induction of antiviral immunity by inhibiting the expression levels of IFN-ß and IFN-stimulated genes (ISGs), such as ISG54 and ISG56, at the late stage of viral infection. At the same time, our results showed that EV71 infection significantly inhibited ubiquitination of RIG-I. In contrast, up-regulation of RIG-I ubiquitination promoted expression of IFN-ß and ISGs, suggesting that inhibition of cellular type I interferon signaling was caused by down-regulation of RIG-I ubiquitination during EV71 infection. These results suggest that inhibition of RIG-I-mediated type I IFN responses by EV71 may contribute to the pathogenesis of viral infection.

scFv antibodies against infectious bursal disease virus isolated from a combinatorial antibody library by flow cytometry.

Infectious bursal disease is an economically important disease that affects chickens worldwide. Here, a recombinant single chain variable fragment (scFv) antibody library derived from chickens immunized with VP2 protein of infectious bursal disease virus (IBDV) was constructed. The library was subjected to three rounds of screening by flow cytometry against VP2 protein through a bacteria display technology, resulting in the enrichment of scFv. Three scFv clones with different fluorescence intensity were obtained by random colony pick up. The isolated scFv antibodies were expressed and purified. Relative affinity assay showed the three clones had different sensitivity to VP2, in accordance with fluorescence activity cell sorting analysis. The potential use of the selected IBDV-specific scFv antibodies was demonstrated by the successful application of the isolated antibodies in western blotting assay and ELISA.

[Antitumor efficacy of the recombinant Newcastle disease virus rNDV-IL15 on melanoma models].

In order to enhance the antitumor efficacy of recombinant Newcastle disease virus, rNDV-IL15 was rescued in this study. Recombinant plasmid prNDV-IL15 was constructed, and BHK21 cells were transfected with the recombinant plasmid. Finally, the recombinant Newcastle disease virus rNDV-IL15 was successfully rescued. The growth curves of these two recombinant viruses were determined. Murine melanoma B16F10 cells were infected with rNDV-IL15 at MOI of 0.1, and the expression level of IL15 in the supernatant was detected by ELISA. The antitumor efficacy of rNDV-IL15 and rNDV was compared in vitro and in vivo. Results showed that prNDV-IL15 was constructed and recombinant virus rNDV-IL15 was successfully rescued. The growth curve of rNDV-IL15 showed that the growth of rNDV-IL15 had not been changed after insertion of IL15 gene. Results showed that there was high level of IL15 expression in the supernatant of rNDV-IL5-infected B16F10 cells (1 044.3 +/- 27.7 ng x mL(-1)). rNDV-IL15 and rNDV significantly inhibited the growth of B16F10 cells in vitro in a time-dependent manner. However, there was no significant difference between them. In animal experiments, rNDV-IL15 efficiently suppressed tumor growth in vivo when compared with rNDV, and the difference was statistically significant. The results suggested that rNDV-IL15 is a more effective antitumor agent.