Immobilized Luminescent Bacteria for the Detection of Mycotoxins under Discrete and Flow-Through Conditions

Abstract

A biosensitive element in the form of bacterial Photobacterium phosphoreum cells immobilized in poly(vinyl alcohol) cryogel was tested for the determination of different mycotoxins under discrete and flow-through analysis conditions. The immobilized bioluminescent cells made it possible to quantify the presence of Ochratoxin A, Sterigmatocystin, Zearalenone, and Deoxynivalenon in aqueous media in a wide range of their concentrations (0.017–56 mg/L, 0.010–33 mg/L, 0.009–14 mg/L, and 0.026–177 mg/L, respectively) via measuring the quenching of cell luminescence. The flow conditions allowed the analysis sensitivity to be improved by an order of magnitude in terms of detected concentrations. Using the immobilized luminescent bacterial cells, we have shown the possibility of evaluating the efficiency of the mycotoxins’ hydrolysis under the action of enzymes. In this way, a 94 ± 4.5% efficiency of Zearalenone hydrolysis with hexahistidine-containing organophosphorus hydrolase for 1h-long treatment of the mycotoxin solution (100 mg/L) was shown.

Metal Nanoparticles for Improving Bactericide Functionality of Usual Fibers

“…Biocide activity of metal nanoparticles towards luminescent bacteria were measured using the known method [ 16 ] with a Photobacterium phosphoreum B-1717 (All-Russian Collection of Industrial Microorganisms) immobilized in a poly(vinyl alcohol) cryogel. Briefly, the granules of immobilized bacteria were placed into a 100 μL of 0.3–30,000 ng/mL metal nanoparticle in a 2% NaCl water solution and incubated at 10 ± 1 °C for 30 min.…”

“…Initially no cytotoxicity of metal nanoparticles at concentrations of 0 using MTT assay with mouse fibroblast NIH/3T3 cell line (Supplementar After that, their cytotoxicity was issued with a luminescent P immobilized within a poly(vinyl alcohol) cryogel [16,18]. Cytotoxic effe on the metal used ( Figure 3), and was maximal for Ta and Zn nanopartic According to preliminary results with disk diffusion assay, function bactericide activity towards both Bacillus cereus 8035 and Staphylococcus ( Supplementary Figures S7-S10).…”

“…Further bactericide activity of met (Escherichia coli) and gram-positive (Bacillus su Gram-negative E. coli were more resistant, nanoparticles obtained both in ethanol and wa μg/mL and 10-27 μg/mL, respectively ( Figure S6). After that, their cytotoxicity was issued with a luminescent Photobacterium phosphoreum obilized within a poly(vinyl alcohol) cryogel [16,18]. Cytotoxic effect was variable, depending e metal used (Figure 3), and was maximal for Ta and Zn nanoparticles.…”

“…), Ti ( 7 of 12 noparticles at concentrations of 0.125-8 μg/mL was revealed NIH/3T3 cell line (Supplementary Figure S6). s issued with a luminescent Photobacterium phosphoreum l) cryogel [16,18]. Cytotoxic effect was variable, depending aximal for Ta and Zn nanoparticles.…”

“…Initially no cytotoxicity of metal nanoparticles at concentrations of 0.125-8 μg/mL was revealed using MTT assay with mouse fibroblast NIH/3T3 cell line (Supplementary Figure S6). After that, their cytotoxicity was issued with a luminescent Photobacterium phosphoreum immobilized within a poly(vinyl alcohol) cryogel [16,18]. Cytotoxic effect was variable, depending on the metal used ( Figure 3), and was maximal for Ta and Zn nanoparticles.…”