Isolation, identification and safety evaluation of OTA-detoxification strain Pediococcus acidilactici NJB421 and its effects on OTA-induced toxicity in mice

Highly efficient electrochemiluminescent properties of porphyrin-based metal-organic framework Zn-TCPP and its immunoassay application to the detection of ochratoxin A

BACKGROUND

Ochratoxin A (OTA) is a group of mycotoxins that are widely distributed in food and feed and are closely associated with human health, so it is particularly important to detect OTA in cereal-based foods. Porphyrins and their derivatives have been widely investigated for their excellent electrochemical luminescence properties. Tetrakis 4-carboxyphenyl) porphyrin (TCPP) has limited applications because of its tendency to aggregate in water.

RESULTS

To enhance the luminescence efficiency of TCPP, the porphyrin can be immobilized as an organic ligand in a metal-organic framework. This allows the preparation of a novel zinc-porphyrin-based MOF (Zn-TCPP nanorods), which in turn provides highly efficient and stable cathodic ECL signals. Herein, an ultra-sensitive electrochemiluminescence immunoassay was proposed using Zn-TCPP nanorods as high-efficiency luminophores and Bi2S3@Au nanoflowers as electrode substrate materials for the detection of ochratoxin A in foodstuffs. Zn-TCPP has a strong and stable signal, and has been used as an immunosensor probe material. The Bi2S3@Au nanoflowers was used to decorate the glass carbon electrode and support for antibody immobilization due to its good electrical conductivity and large specific surface area. Under the optimized conditions, the constructed immunosensor could realize the sensitive detection of ochratoxin A in the detection range of 0.0004 ng mL-1 to 500 ng mL-1 with the detection limit as low as 0.13 pg mL-1. In addition, the sensing platform has been used for the detection of OTA in wheat flour and feed.

SIGNIFICANCE

Hence, it is worth believing that this strategy can pave a bright research direction for the detection of ochratoxin A or other small molecule mycotoxins content in foods, as well as contributing to the further study of MOF in the field of ECL.

A label-free ratiometric homogeneous electrochemical aptasensor based on dual catalytic hairpin self-assembly for rapid and sensitive detection of ochratoxin A in food

The food contamination with Ochratoxin A (OTA) has highlighted the need to create precise, sensitive, and convenient techniques. Herein, we proposed a label-free and immobilization-free ratiometric homogeneous electrochemical aptasensor based on dual catalytic hairpin self-assembly (CHA) for OTA detection. Methylene blue (MB) and ferrocene (Fc) in solution were utilized as label-free signaling molecules, generating a response signal (IMB) and a reference signal (IFc), respectively. The ratio of IMB/IFc was utilized as a measure to quantify OTA. Dual CHA was exploited to increase the ratiometric signal and enhance the amplification efficiency. This aptasensor achieved trace-level detection for OTA over a linear range of lower concentrations (1.0 × 10-3 ng/mL-1.0 × 103 ng/mL) with LOD of 92 fg/mL. The aptasensor was successfully applied to detect OTA in cereal and wine, with comparable results of HPLC-MS/MS. This strategy provided a viable platform for rapid, sensitive, and accurate detection of OTA in food.

Ferroptosis is involved in quercetin-mediated alleviation of Ochratoxin A-induced kidney damage

Ochratoxin A (OTA) induces kidney damage in animals and humans. Ferroptosis is an iron-dependent form of regulated cell death that is involved in OTA-induced kidney injury. Quercetin (QCT), which is commonly found in numerous fruit and vegetables, has extensive pharmacological properties, such as anti-oxidant and anti-inflammatory. The present study aimed to evaluate the effects of QCT on OTA-induced kidney damage and the associated ferroptosis mechanism in mice. The results showed that OTA induced kidney damage, as demonstrated by the presence of kidney histopathological lesions, increased serum BUN and CRE levels, mRNA levels of Ntn1, Kim1, Tnfa, Ilb and Il6, and immunofluorescence of TNFα. OTA induced lipid peroxidation and ferroptosis by increasing the MDA level, 4-HNE production, and the iron concentration, decreasing the GSH content, increasing ACSL4 and HO-1 mRNA and protein levels, and decreasing GPX4 mRNA and protein levels. QCT supplementation alleviated OTA-induced kidney damage and inhibited OTA-induced lipid peroxidation and ferroptosis by reversing the OTA-induced above changes. Erastin weakened the protective effects of QCT on the histopathological damage, renal function, and inflammation induced by OTA. These findings indicated that QCT alleviated OTA-induced kidney injury through ferroptosis, suggesting that QCT might serve as a feed additive in mycotoxin contamination environments.

Impact of Pediococcus acidilactici GLP06 supplementation on gut microbes and metabolites in adult beagles: a comparative analysis

There is growing interest in the potential health benefits of probiotics for both humans and animals. The study aimed to investigate the effects of feeding the canine-derived probiotic Pediococcus acidilactici GLP06 to adult beagles by analysing the microbiome and metabolome. Twenty-four healthy adult beagles were randomly assigned to four groups. The CK group received a standard diet, while the three probiotic groups, the LG group (2 × 108 CFU/day/dog), MG group (2 × 109 CFU/day/dog), and HG group (2 × 1010 CFU/day/dog), received the standard diet supplemented with varying amounts of probiotics. The results show that, compared to the CK group, total antioxidant capacity was significantly increased in the MG and HG groups (p < 0.05), and superoxide dismutase and catalase were significantly increased in the HG group (p < 0.05). Compared to the CK group, malondialdehyde and blood urea nitrogen content were significantly decreased in the MG and HG groups (p < 0.05). Additionally, secretory immunoglobulin A activity was significantly increased in the HG group compared to the CK and LG groups (p < 0.05), and immunoglobulin G activity was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). In addition, compared with the CK group, the abundance of Faecalitalea and Collinsella increased in the LG group, and the relative abundance of Tyzzerella and Parasutterella increased in the MG group. The α diversity and the relative abundances of beneficial bacteria (Faecalibacterium, Lachnospiraceae_NK4A1316, and Ruminococcaceae_UCG-005) were higher in the HG group than in the CK group. Furthermore, acetic acid content was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). Butyric acid, isobutyric acid, and the total SCFA content were significantly increased in the HG group compared to the CK group (p < 0.05). Moreover, metabolome analysis revealed 111 upregulated and 171 downregulated metabolites in the HG group. In conclusion, this study presents evidence that supplementing with P. acidilactici GLP06 can have a positive impact on antioxidant activity, immunoproteins, SCFAs, and gut microbiota in adult beagles. These findings highlight the potential of probiotics as a dietary intervention to enhance gut health and overall wellbeing in companion animals.

Gut Microbiome Analysis and Screening of Lactic Acid Bacteria with Probiotic Potential in Anhui Swine

With the widespread promotion of the green feeding concept of "substitution and resistance", there is a pressing need for alternative products in feed and breeding industries. Employing lactic acid bacteria represents one of the most promising antimicrobial strategies to combat infections caused by pathogenic bacteria. As such, we analyzed the intestinal tract of Anhui local pig breeds, including LiuBai Pig, YueHei Pig, and HuoShou Pig, to determine the composition and diversity of intestinal microbiota using 16S rRNA. Further, the functionality of the pigs' intestinal microbiota was studied through metagenomic sequencing. This study revealed that lactic acid bacteria were the primary contributors to the functional composition, as determined through a species functional contribution analysis. More specifically, the functional contribution of lactic acid bacteria in the HuoShou Pig group was higher than that of the LiuBai Pig and YueHei Pig. Subsequently, the intestinal contents of the HuoShou Pig group were selected for the screening of the dominant lactic acid bacteria strains. Out of eight strains of lactic acid bacteria, the acid-production capacity, growth curve, and tolerance to a simulated intestinal environment were assessed. Additional assessments included surface hydrophobicity, the self-aggregation capability, co-agglutination of lactic acid bacteria with pathogenic bacteria, and an in vitro bacteriostatic activity assay. Lactobacillus johnsonii L5 and Lactobacillus reuteri L8 were identified as having a strong overall performance. These findings serve as a theoretical basis for the further development of pig-derived probiotics, thereby promoting the application of lactic acid bacteria to livestock production.

Insights into the intestinal toxicity of foodborne mycotoxins through gut microbiota: A comprehensive review

Mycotoxins, which are fungal metabolites, pose a significant global food safety concern by extensively contaminating food and feed, thereby seriously threatening public health and economic development. Many foodborne mycotoxins exhibit potent intestinal toxicity. However, the mechanisms underlying mycotoxin-induced intestinal toxicity are diverse and complex, and effective prevention or treatment methods for this condition have not yet been established in clinical and animal husbandry practices. In recent years, there has been increasing attention to the role of gut microbiota in the occurrence and development of intestinal diseases. Hence, this review aims to provide a comprehensive summary of the intestinal toxicity mechanisms of six common foodborne mycotoxins. It also explores novel toxicity mechanisms through the "key gut microbiota-key metabolites-key targets" axis, utilizing multiomics and precision toxicology studies with a specific focus on gut microbiota. Additionally, we examine the potential beneficial effects of probiotic supplementation on mycotoxin-induced toxicity based on initial gut microbiota-mediated mycotoxicity. This review offers a systematic description of how mycotoxins impact gut microbiota, metabolites, and genes or proteins, providing valuable insights for subsequent toxicity studies of mycotoxins. Furthermore, it lays a theoretical foundation for preventing and treating intestinal toxicity caused by mycotoxins and advancing food safety practices.

Farnesoid X Receptor Plays a Key Role in Ochratoxin A-Induced Nephrotoxicity by Targeting Ferroptosis In Vivo and In Vitro

The mycotoxin ochratoxin A (OTA) causes nephrotoxicity, hepatotoxicity, and immunotoxicity in animals and humans. The farnesoid X receptor (FXR) is a member of the NR family and is highly expressed in the kidney, which has an antilipid production function. Ferroptosis is an iron-dependent form of regulated cell death involved in several pathophysiological cell death and kidney injury. The present study aims to evaluate the role of FXR and ferroptosis in OTA-induced nephrotoxicity in mice and HK-2 cells. Results showed that OTA induced nephrotoxicity as demonstrated by inducing the histopathological lesions and neutrophil infiltration of the kidney, increasing serum BUN, CRE, and UA levels, increasing Ntn-1, Kim-1, and pro-inflammatory cytokine expression, and decreasing IL-10 expression and the cell viability of HK-2 cells. OTA treatment also induced FXR deficiency, ROS release, MDA level increase, GSH content decrease, and 4-HNE production in the kidney and HK-2 cells. OTA treatment induced ferroptosis as demonstrated by increasing labile iron pool and lipid peroxidation levels as well as Acsl4, TFR1, and HO-1 mRNA and protein levels, decreasing GPX4 and FTH mRNA and protein expressions, and inducing mitochondrial injury. The FXR activator (GW4064) rescued the accumulation of lipid peroxides, intracellular ROS, and Fe2+, inhibited ferroptosis, and alleviated OTA-induced nephrotoxicity. The ferroptosis inhibitor (Fer-1) prevented ferroptosis and attenuated nephrotoxicity. Collectively, this study elucidates that FXR played a critical role in OTA-induced nephrotoxicity via regulation of ferroptosis, which provides a novel strategy against OTA-induced nephrotoxicity.