In this study, Aspergillus niger RAF106 could effectively degrade AFB1 when cultivated in Sabouraud dextrose broth (SDB) with contents of AFB1 ranging from 0.1 to 4 μg/mL. Microbial degradation is an effective and attractive method for eliminating aflatoxin B1 (AFB1), which is severely toxic to humans and animals. This study provides a novel production strain for compounds 1, 2, 3 and 5, and four potential promising anticancer agents. In addition, compounds 1, 2, 3 and 5 was first found to have the ability to inhibit the invasion and migration of A549 cells (lung cancer cells), which exhibited the potentiality for these compounds to be used as novel anticancer drugs. The minimum inhibitory concentrations (MICs) against Staphylococcus aureus, Klebsiella aerogenes and Proteus vulgaris are 160 µg/mL, 100 µg/mL, 120 µg/mL for the compound 3 and 180 µg/mL, 130 µg/mL 150 µg/mL for the compound 5, respectively. Compounds 3 and 5 exhibit antibacterial activity against Staphylococcus aureus, Klebsiella aerogenes and Proteus vulgaris. Herein, four cyclic dipeptides, namely, cyclo(L-Val-L-Pro) (compound 1), cyclo(L-Pro-L-Leu) (compound 2), cyclo(L-Pro-L-Tyr) (compound 3) and cyclo(L-Pro-L-Phe) (compound 5), and an N-acetyltyramine (compound 4) were first isolated and identified as products of the marine Streptomyces griseorubens f8. Marine actinomycetes are a potential source of a wide variety of bioactive natural products. These findings led us to suggest that these actinobacterial strains could be used as decontamination treatments for the reduction of AFB1 content. Among the latter, strains ACD6 and ABH19 showed no adsorption mechanism involved, suggesting a potential degradation mechanism. The three most efficient reducers (94.9–97.6%) were two strains belonging to the genus Streptomyces and one to the genus Saccharothrix. AFB1 content was reduced by all strains (42.9–97.6%). After a 4-day incubation at 30☌ on AFB1-supplemented medium (5 ppm of AFB1), AFB1 was extracted and quantified. Secondly, each strain’s efficacy to reduce pure AFB1 content was studied in ISP2-medium.
Firstly, morphological study and molecular analysis, based on the 16S rRNA gene, indicated that these strains belong to Actinomadura, Nocardiopsis, Nonomuraea, Saccharothrix and Streptomyces genera. In order to reduce AFB1 occurrence in foodstuffs, 13 strains of mycelial actinobacteria were tested in vitro for the efficacy to reduce AFB1 content all were isolated from the Saharan soils of Algeria. Overall, this study provides new insights on the risk of MP for the marine ecosystem, their ability to accumulate xenobiotics and transfer them to marine biota, with potential adverse repercussion on their health status.Aflatoxin B1 (AFB1) is a carcinogenic compound produced by filamentous fungi. About apoptosis/DNA repair processes, P53 and DNA-ligase increased at 1-day exposure in all conditions, whereas after 3 days increase of bax, Cas-3 and P53 and decrease of Bcl-2 and DNA-ligase were revealed, suggesting a shift towards a cell apoptotic event in exposed mussels. Both contaminants induced cytotoxic and genotoxic effects on hemocytes as determined by lysosomal membrane stability (LMS), micronuclei frequency (FMN), and DNA fragmentation rate by terminal dUTP nick-end labeling (TUNEL). An increase of BP was detected in mussels after 3-day exposure, particularly when mixed with MP. Raman Microspectroscopy (RMS) revealed bioaccumulation in mussel hemolymph of MP, characterized by polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyethylene vinyl acetate (PEVA) and high-density polyethylene (HDPE), with abundance of MP sized 1.22–0.45 µm. Herein, impact of ecologically relevant concentrations of environmental MP alone (50 µg/L) or combined with BP (1 µg/L) was assessed in mussel Mytilus galloprovincialis after a short-term exposure (1 and 3 days) to environmental MP collected from a north-Mediterranean beach. However, the effects of environmental microplastics combined with other pollutants are still poorly investigated. The hazard of microplastic (MP) pollution in marine environments is a current concern.
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