Protein biomarker for early diagnosis of microbial toxin contamination: Using Aspergillus flavus as an example

Abstract

Microbial toxins are important factors that contribute to human diseases and food losses. Predicting the production of these toxins before they occur is a significant challenge. In this study, we innovatively developed a strategy called targeted acquisition of toxin‐related immunogen (TATRI) to identify early diagnostic biomarkers for microbial toxins. Taking Aspergillus flavus as an example, we employed an immunoassay‐based screening approach to identify nanobodies that exhibited significant response signals to different toxigenic strains. Subsequently, we isolated and purified the specific immunogen pre‐aflatoxin biomarker PAB‐01 that bound to the selected nanobody. The results showed that the level of PAB‐01 was positively correlated with the toxin‐producing ability of A. flavus strains and could be detected before the production of aflatoxins. It met the essential requirements as an early diagnostic biomarker for aflatoxin contamination. Protein identification and bioinformatics analysis revealed that PAB‐01 is a glycoprotein that can be secreted into the extracellular space. It is located on chromosome 5 of A. flavus and belongs to the 75 family of glycoside hydrolases. Furthermore, we used 7 g/kg as the critical concentration of PAB‐01 to diagnose the risk of aflatoxin contamination in stored peanuts, with an accuracy rate of 75.9% for high‐risk samples. In summary, this work provides a promising approach for the identification of protein biomarkers prior to microbial toxin production and the establishment of early diagnostic techniques for microbial toxins.

Peanut Rhizosphere Achromobacter xylosoxidans Inhibits Aspergillus flavus Development and Aflatoxin Synthesis by Inducing Apoptosis through Targeting the Cell Membrane

“…The soil-borne fungus A. flavus produces aflatoxins, a toxic substance that contaminates lipid-rich seed crops and poses a serious threat to human health and agricultural productivity. 41,42 A. flavus can overwinter in crop roots and re-emerge in the spring, infecting new crops. 43 Conventional fungicides are largely ineffective against A. flavus in edible plant parts, and the fungus has developed resistance to some antimicrobial agents.…”

“…The soil-borne fungus A. flavus produces aflatoxins, a toxic substance that contaminates lipid-rich seed crops and poses a serious threat to human health and agricultural productivity. , A. flavus can overwinter in crop roots and re-emerge in the spring, infecting new crops .…”

p‐Anisaldehyde suppresses Aspergillus flavus infection and aflatoxin biosynthesis via targeting cell structure and Ap1‐regulatory antioxidant system

“…flavus is widely distributed in soil, decaying vegetation, postharvest crop products, and indoor environments (Amaike & Keller, 2011;Ding et, al., 2023). A. flavus is notorious for its affinity of invading lipidrich seed crops and produce a variety of aflatoxins (AFs) (Fu et al, 2023), among which AFB1 is considered one of the most significant health risks for its carcinogenic and teratogenic properties to humans.…”

The Autophagy-Related Protein ATG8 Orchestrates Asexual Development and AFB1 Biosynthesis in Aspergillus flavus

“…Among the AFs, aflatoxins B1, B2, G1, and G2 are the major four and aflatoxin B1 (AFB1), the most toxic and potent hepatocarcinogenic compound among them, primarily targets the liver [3,4]. Chronic low-level exposure to AFB1 can lead to immunosuppression and hepatocellular carcinoma, while a single acute exposure could be fatal [5,6]. Additionally, A. flavus, the second most common cause of aspergillosis after Aspergillus fumigatus, poses a significant threat to immunocompromised individuals [7][8][9].…”