Evaluation of Phenolic Compound Toxicity Using a Bioluminescent Assay with the Fungus Gerronema viridilucens

Abstract

Basidiomycetes (phylum Basidiomycota) are filamentous fungi characterized by the exogenous formation of spores on a club‐shaped cell called a basidium that are often formed on complex fruiting bodies (mushrooms). Many basidiomycetes serve an important role in recycling lignocellulosic material to higher trophic levels, and some show symbiotic relationships with plants. All known bioluminescent fungi are mushroom‐forming basidiomycetes in the order Agaricales. Hence, the disruption of the basidiomycete community can entirely compromise the carbon cycle in nature from fungi to higher trophic levels. The fungus Gerronema viridilucens was used in the present study to investigate the toxicity of a phenolic compound series based on the inhibition of its bioluminescence. The median effect concentration (EC50) obtained from curves of bioluminescence inhibition versus log [phenolic compound] showed that 2,4,6‐trichlorophenol was the most toxic compound in the series. The log EC50 values of all phenolic compounds were then used for the prediction of their toxicity. The univariate correlation of log EC50 values obtained from 6 different phenolic compounds was stronger with the dissociation constant (pKa) than with 1‐octanol/water partition coefficient (KOW). Nevertheless, the toxicity can be better predicted by using both parameters, suggesting that the phenol‐driven uncoupling of fungus mitochondrial adenosine triphosphate synthesis is the origin of phenolic compound toxicity to the test fungus. Environ Toxicol Chem 2020;39:1558–1565. © 2020 SETAC

Low-Cost, User-Friendly, All-Integrated Smartphone-Based Microplate Reader for Optical-Based Biological and Chemical Analyses

“…Despite this, the device can detect the PCP in its relevant range, demonstrating again its versatility and ability to support sensing assays based on bioluminescent. 72 Drug Screening Test. Finally, we demonstrate the use of our portable reader to perform a conventional growth inhibition assay.…”

Implicitly perturbed Hamiltonian: a class of versatile and general-purpose molecular representations for machine learning

“…For inhibition of the CYP450, as it is implied from the physics of the problem, the free energy of solvation of drug candidates in different solvents can determine the free energy of docking the drugs to the active site of the enzyme [64,65]. To that end, the most widely considered solvents are octanol and water, commonly employed as octanol-water partition coefficient [66][67][68][69][70]. Very interestingly, these two solvents are also present in all of the developed machine-learning models with the highest efficiency in evaluating the CYP450 inhibition.…”

Fungal bioassays for environmental monitoring

“…Most reports regarding the use of fungi in bioassays show the effect of soil pollutants or pure substances, including metal cations, organochlorine, and phenolic compounds, on the growth of mycelium cultures using methodologies based on biomass quantification, enzymatic activity, bioluminescence, and plate occupation diameters ( Mendes and Stevani, 2010 ; Chan-Cheng et al, 2020 ; Ventura et al, 2020 ) ( Figure 2 ).…”

“…Recently, the application of fungi bioluminescence system has been demonstrated to respond, albeit not specifically, to several metal cations such as Cd(II) and Cu(II), and phenolic compounds by bioluminescent basidiomycetes Neonothopanus gardneri, Gerronema viridilucens , Armillaria mellea, and Mycena citricolor ( Weitz et al, 2002 ; Mendes et al, 2010 ; Mendes and Stevani, 2010 ; Stevani et al, 2013 ; Ventura et al, 2020 , 2021 ). In an agar medium, the bioassay with the fungus N. gardneri , which responds in a more sensitive and repeatable way, can be conducted by exposing the mycelium for 30 min or 24 h to an aqueous solution containing the toxicant.…”

“…Bioluminescence is a precocious endpoint that can indicate the toxic effect of the sample. There is evidence that the decrease of light emission in the presence of the toxicant is related to the uncoupling of mitochondrial oxidative phosphorylation, leading to the impairment of ATP biosynthesis ( Ventura et al, 2020 ). Likewise, other bioluminescent microorganisms, like bacteria, respond to toxic substances by decreasing light emission proportionally to concentration of the toxicant ( Hollis et al, 2000 ; Weitz et al, 2002 ; Mendes and Stevani, 2010 ; Ventura et al, 2020 , 2021 ).…”