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

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.

Current status of research on fungal bioluminescence: biochemistry and prospects for ecotoxicological application.

Over the last half decade the study of fungal bioluminescence has regained momentum since the involvement of enzymes has been confirmed after over 40 years of controversy. Since then our laboratory has worked mainly on further characterizing the substances involved in fungal bioluminescence and its mechanism, as well as the development of an ecotoxicological bioluminescent assay with fungi. Previously, we proved the involvement of a NAD(P)H-dependent reductase and a membrane-bound luciferase in a two-step reaction triggered by addition of NAD(P)H and molecular oxygen to generate green light. The fungal luminescent system is also likely shared across all lineages of bioluminescent fungi based on cross-reaction studies. Moreover, fungal bioluminescence is inhibited by the mycelium exposure to toxicants. The change in light emission under optimal and controlled conditions has been used as endpoint in the development of toxicological bioassays. These bioassays are useful to better understand the interactions and effects of hazardous compounds to terrestrial species and to assist the assessment of soil contaminations by biotic or abiotic sources. In this work, we present an overview of the current state of the study of fungal luminescence and the application of bioluminescent fungi as versatile tool in ecotoxicology.

(99m)Tc-anti-TNF-α scintigraphy in RA: a comparison pilot study with MRI and clinical examination.

OBJECTIVE: To compare the use of radiolabelled human monoclonal anti-TNF-α scintigraphy with clinical examination and MRI of hands and wrists joints in patients with active RA. METHODS: Eight patients with active RA, 28-joint DAS (DAS-28) ≥ 3.2 and a healthy volunteer underwent whole body and hand/wrist scintigraphy after the administration of anti-human TNF-α labelled with technetium-99m ((99m)Tc). One hundred and ninety-eight joints were examined. Patients were also given clinical examinations in addition to MRI of the hands and wrists. RESULTS: Of the 198 joints examined, signs of inflammation were detected by MRI in 49 (24.7%) and by scintigraphy in 48 (24.2%) joints, with agreement between the two methods in 44 joints. In five joints, MRI was positive and scintigraphy negative. In another four joints, scintigraphy was positive and MRI negative for signs of inflammation. MRI and scintigraphy were in agreement for negative results for 145 joints. The sensitivity and specificity of scintigraphy was 89.8 and 97.3%, respectively. When clinical parameters (presence of swelling and tenderness of joints) were compared with the MRI findings, lower correlation coefficients were observed (sensitivity of 59.2% and 65.3%, respectively). CONCLUSIONS: Scintigraphy using (99m)Tc-anti-TNF-α showed high correlation with the presence of inflammatory signs detected by MRI in the hands and wrists of patients with active RA, and demonstrated a greater sensitivity than clinical examination. These results can assist in better understanding of anti-cytokine therapy and support the achievement of evidence-based biologic therapy.

Influence of culture conditions on mycelial growth and bioluminescence of Gerronema viridilucens.

Herein we describe a procedure for measuring the total light emission of the naturally bioluminescent tropical fungus Gerronema viridilucens and the optimization of culture conditions using multivariate factorial anova. Cultures growing on an agar surface in 35 mm Petri dishes at 90% humidity show optimal bioluminescence emission at 25 degrees C in the presence of 1.0% sugar cane molasses, 0.10% yeast extract and pH 6.0 (nonbuffered). Temperature and pH are the most important factors for both mycelial growth and bioluminescence.

Pellegrini-Stieda disease: a heterogeneous disorder not synonymous with ossification/calcification of the tibial collateral ligament-anatomic and imaging investigation.

OBJECTIVE: Ossification/calcification around the medial femoral condyle has been known as Pellegrini-Stieda (PS) disease for almost 100 years. Little attention has been given to magnetic resonance (MR) imaging characteristics. Our purpose is to demonstrate the anatomy in the medial femoral compartment and imaging findings of PS disease, determining the sites and patterns of ossification. DESIGN AND PATIENTS: In a cadaveric study seven specimens were dissected to show the anatomic relations of the tibial collateral ligament (TCL) and the tendon of the ischiocondylar part of the adductor magnus muscle, in the medial femoral epicondyle. In order to determine the nature of ossification/calcification in PS disease, MR imaging and radiographic findings in nine patients were analyzed by two observers with attention to the specific site, shape, and orientation of the ossification and its relationship to the tibial collateral ligament (TCL) and adductor magnus tendon. Available clinical history was recorded. A classification system addressing different sites and patterns of ossification was developed. RESULTS: The anatomic study showed that the TCL and the adductor magnus tendon insert at different sites in the medial femoral condyle and there is no continuation; however, some fibers of the posterior bundle of the TCL overlap the anterior aspect of the adductor magnus tendon. The imaging study showed that shape, orientation, and location of the abnormal calcification and ossification were similar on radiographic and MR imaging analysis. Ossification had an inferior orientation in six cases, a superior orientation in two cases, and both in one case. Four patterns of ossification were noted: (I) a beak-like appearance with an inferior orientation and femoral attachment was present in five cases; (II) a drop-like appearance with an inferior orientation, parallel to the femur, was evident in one case; (III) an elongated appearance with a superior orientation, parallel to the femur, was seen in two cases; and (IV) a beak-like appearance with an inferior and superior orientation, attached to the femur, was seen in one case. The ossification was present in the TCL in six cases, in the adductor magnus tendon in two cases, and in both in one case. The coronal plane was best in detecting and categorizing the ossification. CONCLUSION: Our data indicate that ossification in PS disease is not confined to the TCL but may also involve the adductor magnus tendon. In some cases, it can be related to the anatomic proximity (overlap) of the fibers of these two structures. PS disease should not be regarded as synonymous with ossification of the TCL. The ossification may be classified into four types. No clinical differences among these types appear to exist.