Simultaneous degradation of aflatoxin B1 and zearalenone by Porin and Peroxiredoxin enzymes cloned from Acinetobacter nosocomialis Y1.

Mycotoxin contamination can cause severe health issues for both humans and animals. This study examined the potential of enzymes derived from Acinetobacter nosocomialis Y1 to simultaneously degrade aflatoxin B1 (AFB1) and zearalenone (ZEN), which could have significant implications in reducing mycotoxin contamination. Two enzymes, Porin and Peroxiredoxin, were identified with molecular weights of 27.8 and 20.8 kDa, respectively. Porin could completely degrade 2 µg/mL of AFB1 and ZEN within 24 h at 80 °C and 60 °C, respectively. Peroxiredoxin could completely degrade 2 µg/mL of AFB1 and reduce ZEN by 91.12% within 24 h. The addition of Na+, Cu2+, and K+ ions enhanced the degradation activities of both enzymes. LC-MS/MS analysis revealed that the molar masses of the degradation products of AFB1 and ZEN were 286 g/mol and 322.06 g/mol, and the products were identified as AFD1 and α or ß-ZAL, respectively. Vibrio fischeri bioluminescence assays further confirmed that the cytotoxicity of the two degradation products was significantly lower than that of AFB1 and ZEN. Based on these results, it can be inferred that the degradation product of ZEN is ß-ZAL. These findings suggest that both enzymes have the potential to be utilized as detoxification enzymes in food and feed.

Potential targets for controlling Bactrocera dorsalis using cuticle- and hormone-related genes revealed by a developmental transcriptome analysis.

BACKGROUND: The oriental fruit fly, Bactrocera dorsalis (Hendel), is an important agricultural pest and has developed resistance to many insecticides. To investigate vital genes participating in metamorphosis for development of additional control strategies, a comprehensive transcriptome analysis covering ten developmental stages of B. dorsalis was performed. RESULTS: There were 2132, 952, 1062, 2301 and 1333 differentially expressed genes identified during hatching, 1st-instar larval molting, 2nd-instar larval molting, pupariation and emergence, respectively. Further expression analyses indicated that genes in hormone- (20-hydroxyecdysone and juvenile hormone) and cuticle- (chitin and cuticle protein) related pathways were essential for metamorphosis in B. dorsalis. Among chitinase (Cht) genes, BdCht-5, -8 and -10 were differentially expressed during larval-larval, larval-pupal and pupal-adult moltings. However, BdCht7 was differentially expressed during egg-larval and larval-larval moltings. Knockdown of BdCht7 at the 1st-instar larval stage disrupted normal development of larvae and was lethal to B. dorsalis. Among cuticle protein (CP) genes, 15 genes (BdCPLCG-1, BdCPLCP-2, BdCPAP1-B2, BdRR1-21, BdRR1-31, BdRR2-15, BdRR2-26, BdRR2-30, BdRR2-32, BdTweedle-9, BdTweedle-24, BdRR2-10, BdCPAP3-C1, BdRR1-34 and BdRR1-41) were differentially expressed during four of five types of moltings. Among hormone-relative genes, BdJHBP-4, -9 and -13 were differentially expressed during all five types of moltings, whereas BdJHBP-5, -12 and BdHR4 were differentially expressed during four of five types of moltings. CONCLUSION: This study reveals critical genes involved in development and metamorphosis of B. dorsaslis, and BdCht7 is dispensable for larval survival. It also provides comprehensive transcriptome information for finding more molecular targets to control this pest. © 2020 Society of Chemical Industry.