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Fundamental Aspects
Published in Bruno Langlais, David A. Reckhow, Deborah R. Brink, Ozone in Water Treatment, 2019
Guy Bablon, William D. Bellamy, Marie-Marguerite Bourbigot, F. Bernard Daniel, Marcel Doré, Françoise Erb, Gilbert Gordon, Bruno Langlais, Alain Laplanche, Bernard Legube, Guy Martin, Willy J. Masschelein, Gilbert Pacey, David A. Reckhow, Ciaire Ventresque
Specific organic chemicals. Several studies have documented the dichotomous ability of aqueous ozone to either destroy or, in contrast, activate (to a mutagenic state) specific classes of organic chemicals. Burleson et al. (1979) reported that ozonation of polyaromatic amines, such as acriflavine, proflavine, and β-napthylamine, and poly-cyclic aromatic hydrocarbons (PAH), such as benzo(a)pyrene, 7,12-dimethylbenz(a)anthracene, and 3-methylcholanthrene, in water (5 mg/L ozone, pH 6.6, 3–15 min) eliminated or reduced the mutagenic activity of these compounds in several strains of Salmonella, including TA98 and TAIOO. Comparable treatment with molecular oxygen had no effect on the mutagenic potential of these chemicals. These same investigators demonstrated that ozone treatment (relative to an equimolar concentration of molecular oxygen) destroyed or reduced the carcinogenicity of PAH to the skin of Lobund CFW mice. The authors considered these chemicals to be either known or potential water contaminants or to be compounds that were structurally related to known water contaminants. This point is probably somewhat specious. Nevertheless, these experiments point out that ozonation may destroy the genotoxic and oncogenic potential of some polycyclic aromatic compounds in aqueous media. In addition, these workers reported that ozone destroys the activity of several other structurally diverse carcinogens (aflatoxin Bl5 bis[2-chloroethyl]amine) and some pesticides (for example, captan and Dexon).
A comparative study of the wild and mutated heavy metal resistant Klebsiella variicola generated for cadmium bioremediation
Published in Bioremediation Journal, 2018
Feruke-Bello Yetunde Mutiat, Babalola Gbolahan, Odeyemi Olu
The sub-inhibitory concentration of ethidium bromide and acridine orange for K. variicola were 1.5 mg/ml and 0.4 mg/ml, respectively. The total viable count (cfu/ml) observed for the wild and the mutant strains of heavy metal resistant K. variicola is presented in Table 4. Acridine orange was observed to be a better mutagenic agent than ethidium bromide for K. variicola. The results corroborated the research carried out by Shakibaie et al. (2008), that acridine orange and acriflavine had maximum effect on the bioremediation of copper and zinc. The survivor rate of 1.92 was recorded for K. variicola in acridine orange as compared to 9.45 observed in ethidium bromide. A total of eight (8) K. variicola mutant strains, four (4) from each of the mutagenic agent, were recovered from the MSA supplemented with different concentrations of the cadmium salt. The mutant strains were assigned codes (MutEa – MutEd) for those from ethidium bromide and (MutAa – MutAd) for the strains from acridine orange. The mutation experiment did not affect the pigmentation of all the mutant strains and some other morphological characteristics were still intact. In addition, the chemical mutagen did not affect the biochemical characteristics of all the mutant strains recovered.
Molecular study of Chlorhexidine resistance in Methicillin Resistant Staphylococcus aureus
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Salma O. Ghanim, Heba E. Eldegla, Marwa E. Sallam, Gamal M. Abdel-Fattah
When the antiseptic susceptibility to a QAC known as acriflavine and gene distributions of MRSA isolates were investigated in Japan in 1992, 71.4% of the MRSA showed resistance to this antiseptic. Also, qacA/B and smr were determined in 10.2% and 20.4% of the isolates, respectively. However, in 1999, qacA/B and smr were found in 47.9% and 3%, respectively [33].