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Animal Models for Phototoxicity Testing
Published in Francis N. Marzulli, Howard I. Maibach, Dermatotoxicology Methods: The Laboratory Worker’s Vade Mecum, 2019
Lark A. Lambert, Wayne G. Warner, Andrija Kornhauser
The Daniels test, using the pathogenic yeast Candida albicans, is one of the best known examples of early in vitro phototoxicity tests (Daniels, 1965). The test measures the inhibition of cell growth in an agar medium after the yeast is exposed to a potential phototoxic chemical and light. Although simple to perform, this test does not reliably predict the clinical phototoxicity of compounds such as sulfanilamide and demeclocycline (demethylchlortetracycline) (Daniels, 1965). A nonpathogenic yeast, Candida utilis, has been suggested as an alternative test organism (Kagan and Gabriel, 1980). Bacterial systems have also been studied (Ashwood-Smith et al., 1980; Harter et al., 1976). A quantitative in vitro method of phototoxic evaluation devised by Tenenbaum et al. (1984) used the yeast Saccharomyces cerevisiae. An inhibition curve from 8-MOP phototoxicity was constructed as a standard against which test material could be measured.
Copper Metabolism and Diseases of Copper Metabolism
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
The incorporation of copper into cytochrome c oxidase has been examined in a Candida utilis yeast system.217,218 Low-copper growth conditions specifically inhibit the synthesis of active cytochrome c oxidase in this system, but the apoprotein is apparently synthesized and integrated into the mitochondrial membrane normally. A cytoplasmic peptide or protein was suggested as a requirement for transfer and/or incorporation of copper into this apocytochrome c oxidase. The evidence for this thesis was that cycloheximide, which is known to inhibit cytoplasmic but not mitochondrial protein synthesis, prevented the incorporation of copper into apocytochrome c oxidase when copper-deficient cells were grown in copper-supplemented media. The most striking example of any analogous requirement for a specific cofactor for metalloenzyme activation is with the molybdenum-containing enzymes — nitrogenase, sulfite oxidase, and xanthine oxidase. The unequivocal evidence in those systems is that the apomolybdoprotein produced in the absence of Mo can be activated by an isolated Mo-cofactor which was resolved from the holoenzyme.219 Perhaps there is an analogous cytoplasmic factor involved in cytochrome c oxidase synthesis as suggested above. Exactly how, when, and where copper is incorporated into the cytosolic Cu/Zn-SOD or metallothi-onein or other copper proteins remain unknown.
Fungal sphingolipids: role in the regulation of virulence and potential as targets for future antifungal therapies
Published in Expert Review of Anti-infective Therapy, 2020
Caroline Mota Fernandes, Maurizio Del Poeta
The immunological targeting of GlcCer might represent an efficacious strategy to prevent mortality caused by fungal infections. In fact, the administration of an anti-GlcCer antibody prior to a lethal Cryptococcus infection improved mice survival by 60% [87]. Vaccination of mice with the GlcCer extracted from the nonpathogenic Candida utilis also protected partially against cryptococcosis, preventing fungal dissemination to the brain [88]. These results highlight the potential of GlcCer synthesis pathway for: (i) the development of novel inhibitors that treat invasive infections and (ii) the isolation of lipids that differ structurally from the mammalian counterparts and can be used as antigens in fungal vaccines, preventing mortality, especially in the individuals more susceptible to the invasive mycoses.
Potential application of probiotics in mycotoxicosis reduction in mammals and poultry
Published in Critical Reviews in Toxicology, 2022
Alaleh Zoghi, Svetoslav Dimitrov Todorov, Kianoush Khosravi-Darani
For the evaluation of the ZEA toxic effects on broiler production performance and influences on gut microbiota, Ba. subtilis CGMCC1.0504, L. casei CGMCC1.2884, and Candida utilis CGMCC2.0615 were investigated in a model study (Chang et al. 2020). The optimal ratios of mentioned probiotics in birds’ diets were set as 7, 5, and 6 log CFU/g (Ba. subtilis CGMCC1.0504, L. casei CGMCC1.2884, and C. utilis CGMCC2.0615), respectively. In this study, a total of 7 groups of 50 1-day-old Ross broilers were created. The obtained results were proved that intoxication with ZEA significantly can decrease broiler production performance, associated with damage to the liver and jejunum, and even increase the presence of ZEA residues in the broiler body. However, when a combination of the 3 probiotics was applied, reductions of the ZEA toxicity and negative effects on the above-mentioned parameters were sonically reduced (p < 0.05). In a similar study, supplementation with 40% Ba. subtilis ANSB060 and 40% Ba. subtilis ANSB01G at the rate of 1 kg/ton to laying hen feed containing AF only (123.0 µg/kg) or a combination of AF and ZEA (123.0 and 260.2 µg/kg, respectively), resulting in decreased toxin residues in eggs by 50.81% and 57.76%, respectively (Jia et al. 2016). Jia et al. (2016) suggested that the mode of action of mentioned probiotics is most probably not primarily associated with adsorbing or specific binding toxins to the cell wall, but probably Ba. subtilis is actively involved in the degradation of AF by altering the chemical structures from the AF and ZEA, such as the lactone ring and methoxyl group of the mycotoxins.