Ochratoxin A (OTA) is a widespread mycotoxin commonly found as a corn contaminant. It has been shown to be nephrotoxic, hepatotoxic, teratogenic and immunotoxic to several species of animals and to ...cause kidney and liver tumors in mice and rats. The focus of this article is primarily intended to summarize the progress in research associated with oxidative stress as a plausible mechanism for OTA-induced toxicity as well as its metabolism. The present review shows that studies have been carried out for decades to elucidate the production of reactive oxygen species (ROS) and oxidative stress as a result of OTA treatment and have correlated them with various types of OTA toxicity, indicating that oxidative stress plays critical roles in the toxicity of OTA. The major metabolic pathways of OTA are hydrolysis and a small percentage of absorbed OTA is hydroxylated. CYP450, carboxypeptidase A, trypsin, α-chymotrypsin and cathepsin have been shown to be able to degrade OTA. Most metabolites of OTA are less toxic than OTA except OP-OTA. Further understanding of the role of oxidative stress in OTA-induced toxicity will throw new light on the use of antioxidants, scavengers of ROS, as well as on the blind spots of the metabolism and metabolic enzymes of OTA. The present review might contribute to reveal the oxidative stress-induced toxicity of OTA and help to protect against its oxidative damage.
•Oxidative stress and toxicity induced by OTA.•Metabolic pathways and enzymes of OTA in different species.•Prevention of oxidative stress-induced toxicity by OTA.
Immunoassays are reliable, efficient, and accurate methods for the analysis of small‐molecule harmful substances (such as pesticides, veterinary drugs, and biological toxins) that may be present in ...food. However, traditional polyclonal and monoclonal antibodies are limited by animal hosts and hinder further development of immunoassays. With the gradual application of phage display technology as an efficient in vitro selection technology, the single‐chain fragment variable (scFv) now provides an exciting alternative to traditional antibodies. Efficiently constructed scFv source libraries and specifically designed biopanning schemes can now yield scFvs possessing specific recognition capabilities. A rational mutation strategy further enhances the affinity of scFv, and allows it to reach a level that cannot be achieved by immunization. Finally, appropriate prokaryotic expression measures ensure stable and efficient production of scFv. Therefore, when developing excellent scFvs, it is necessary to focus on three key aspects of this process that include screening, mutation, and expression. In this review, we analyze in detail the preparation and affinity improvement process for scFv and provide insights into the research progress and development trend of scFv‐based immunoassay methods for monitoring small‐molecule harmful substances.
Food contamination with antibiotic residues has become a worldwide problem due to the heavy and improper use of antibiotics. The development of fast, high-throughput, easy, and economical screening ...methods for the detection of antibiotic residues is an important requirement as an alternative to the traditional assays. Immunoassays are widespread promising methods that can achieve the conditions of an analytical method in the evaluation of food and environmental protection. This review offers an overview of the preparation of antibodies and the currently established immune-assays for the antibiotic residues detection, including enzyme-linked immunosorbent assay, fluorescence immunoassay, radioimmunoassay, colloidal gold immunoassay, and chemiluminescence immunoassay. Furthermore, it will elaborate on the future perspective on the performance and improvement of these assays for the determination of antibiotic residues in food samples. These assays include a simple sample preparation and high-sensitive detection that offer a significant assurance for the screening of antibiotic residues.
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•Fermented fruits could ameliorate obesity and fat accumulation.•The gene and protein expressions for fat metabolism were regulated.•The gut microbiota structure was improved.•Due to ...increased leptin level, food intake was reduced.
Some fruits after long-term fermentation have anti-obesity function, however, the mechanisms have not been systematically determined. This study aimed to screen the effective fermented fruits and explore the mechanisms. C57BL/6J male mice were fed with a high fat diet (HFD) to establish an obese model and intervened with nine kinds of fermented fruits individually. Fermented fruits significantly lowered body weight gain (BWG), average daily feed intake (ADFI) and adipose tissue coefficient, and attenuated the hepatic steatosis. Serum triglyceride (TG) and total cholesterol (T-CHO) were significantly reduced, but leptin was remarkably increased. While the expressions of PPARα and CPT1 were upregulated, that of PPARγ and aP2 were downregulated. Additionally, fermented fruits improved the gut microflora structures of HFD-fed mice. This study suggested that fermented fruits, especially fermented blueberry and fermented apple, could ameliorate obesity by controlling food intake and regulating lipid metabolism and gut microbiota dysbiosis, potentially replacing anti-obesity drugs.
The purpose of this study was to establish the clinical breakpoint (CBP) of apramycin (APR) against Salmonella in swine and evaluate its effect on intestinal microbiota. The CBP was established based ...on three cutoff values of wild-type cutoff value (COWT), pharmacokinetic-pharmadynamic (PK/PD) cutoff value (COPD) and clinical cutoff value (COCL). The effect of the optimized dose regimen based on ex vivo PK/PD study. The evolution of the ileum flora was determined by the 16rRNA gene sequencing and bioinformatics. This study firstly established the COWT, COPD in ileum, and COCL of APR against swine Salmonella, the value of these cutoffs were 32 µg/mL, 32 µg/mL and 8 µg/mL, respectively. According to the guiding principle of the Clinical Laboratory Standards Institute (CLSI), the final CBP in ileum was 32 µg/mL. Our results revealed the main evolution route in the composition of ileum microbiota of diarrheic piglets treated by APR. The change of the abundances of Bacteroidetes and Euryarchaeota was the most obvious during the evolution process. Methanobrevibacter, Prevotella, S24-7 and Ruminococcaceae were obtained as the highest abundance genus. The abundance of Methanobrevibacter increased significantly when APR treatment carried and decreased in cure and withdrawal period groups. The abundance of Prevotella in the tested groups was significantly lower than that in the healthy group. A decreased of abundance in S24-7 was observed after Salmonella infection and increased slightly after cure. Ruminococcaceae increased significantly after Salmonella infection and decreased significantly after APR treatment. In addition, the genera of Methanobrevibacter and Prevotella were defined as the key node. Valine, leucine and isoleucine biosynthesis, D-Glutamine and D-glutamate metabolism, D-Alanine metabolism, Peptidoglycan and amino acids biosynthesis were the top five Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in the ileum microbiota of piglets during the Salmonella infection and APR treatment process. Our study extended the understanding of dynamic shift of gut microbes during diarrheic piglets treated by APR.
T-2 toxin (T-2) is one of major concern mycotoxins acknowledged as an unavoidable contaminant in human foods, animal feeds and also agriculture products. Thus, a facile and sensitive method is ...essential for accurate T-2 toxin detection. In our work, a specific electrochemical immunosensor based on gold nanoparticles/carboxylic group-functionalized single-walled carbon nanotubes/chitosan (AuNPs/cSWNTs/CS) composite was established. The mechanism of the electrochemical immunosensor was an indirect competitive binding to a given amount of anti-T-2 between free T-2 and T-2-bovine serum albumin, which was conjugated on covalently functionalized cSWNTs decorated on the glass carbon electrode. Afterwards, the alkaline phosphatase labeled anti-mouse secondary antibody was bound to the electrode surface by reacting with the primary antibody. Lastly, alkaline phosphatase catalyzed the hydrolysis of the substrate α-naphthyl phosphate, which produced an electrochemical signal. Compared with conventional methods, the established immunosensor was more sensitive and simpler. Under optimal conditions, this method could quantitatively detect T-2 from 0.01 to 100 μg·L
with a detection limit of 0.13 μg·L
and favorable recovery 91.42⁻102.49%. Moreover, the immunosensor was successfully applied to assay T-2 in feed and swine meat, which showed good correlation with the results obtained from liquid chromatography-tandem mass spectrometry (LC-MS/MS).
A broad-spectrum microbiological inhibition method has been developed for rapidly screening different kinds of antibiotics such as β-lactam, aminoglycosides, tetracyclines, sulfonamides, macrolides, ...lincosamides and quinolones in milk, chicken egg and honey by using an easy sample preparation. The microbiological system in microtiter plates consists of an agar medium, a mixture of nutrients, test bacteria (
C953), bromocresol purple, and other supplements such as trimethoprim, chloramphenicol, streptomycin and enrofloxacin which helps to improve the detection capability of the microbiological system toward the chosen antibiotics. It was observed that the limit of detection of the kit used in present study for all kinds of antibiotics in milk were lower than or close to maximum residue limits determined by EU or CODEX. For chicken egg and honey, the detection capability of the kit was similar to that determined in milk. Moreover, it was revealed that the kit in present study was more sensitive to aminoglycosides, macrolides and quinolones in various matrixes than internationally available commercial kits. The false-positive and false-negative rates for both were 0%. The coefficient of variations among various factors was all less than 4%. Additionally, the quality guarantee period of the kit was more than 6 months at 4°C. A good correlation between the kit results and the LC-MS/MS results for milk was also observed, which revealed that the kit was reliable to screen antibiotics residues in incurred samples.
•This paper is the first report of a novel hapten containing a pyrimidinyl moiety.•The obtained antibody is the most suitable antibody for the detection of SA residues.•The ic-ELISA can serve as an ...effective screening tool in any routine laboratory.
For high-throughput monitoring of the residues of sulfonamides (SAs) in edible animal tissues, a novel hapten and monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed. The novel hapten was synthesized and conjugated to carrier protein as immunogen. The spleen cells of the inoculated mice expressing group-specificity against SAs were fused. The obtained monoclonal antibody 4E5 showed the cross-reactivity (CR) to 16 structurally different SAs. Based on this antibody, an optimised icELISA protocol was carried out with only phosphate-buffered saline for the fast extraction of SAs in the tissues. The limits of detection of SAs in chicken ranged from 1.5 to 22.3μgkg−1. The recoveries were 70.6–121% with less than 24.1% relative standard deviation. The developed ic-ELISA showed a good correlation with high performance liquid chromatography. It would be a useful tool for the screening of residues of SAs in edible animal tissues.
Amantadine (AMD) is an antiviral drug that is prohibited for use in livestock and poultry. In this study, carboxyl-modified magnetic nanoparticles (MNPs) were synthesized using the solvothermal ...method in one step with harmless and inexpensive regents, and they were used to label monoclonal antibodies (mAbs) of AMD in microwells with electrostatic adsorption. Then, a magnetic immunochromatography assay (MICA) method was successfully established. Under optimal conditions, the MICA showed a good performance, with a linear range of 0.2~10.0 µg/L. The limit of detection (LOD) was 0.068 µg/L with the instrument, and the visual LOD (vLOD) was 0.5 µg/L. There was no cross-reaction with rimantadine and ribavirin. The vLOD in real samples was 1.0 µg/kg. The developed MICA has the advantages of convenience, speed, and sensitivity, which make it suitable for the on-site rapid detection of AMD residues in chicken tissues and eggs.
This is the first report on the screening, expression, and recognition mechanism analysis of single-chain fragment variable (scFv) against phenylethanolamine A (PEAA), a newly emerged β-adrenergic ...agonist illegally used as a feed additive for growth promotion. The PEAA-specific scFv scFv, called scFv-32, was screened from hybridoma cell lines by phage display and was found to be optimally expressed in the E.
coli
system. The ic-ELISA results revealed an IC
50
value of 10.34 μg/L for scFv-32 and no cross-reactivity with other β-adrenergic agonists. Homology modeling and molecular docking revealed the key binding sites VAL178, TYP228, and ASP229. One hydrogen bond, two pi-sigma bonds, and one pi-pi bond maintain the formation of the antibody‒drug complex. Alanine scanning mutagenesis of the three predicted key binding sites showed that the mutants completely lost their recognition activity, which confirmed the accuracy of the theoretical analysis. These results are valuable for the preparation of scFvs and the analysis of the molecular recognition mechanism of antigen-antibodies.
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