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Approaches for Identification and Validation of Antimicrobial Compounds of Plant Origin: A Long Way from the Field to the Market
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Lívia Maria Batista Vilela, Carlos André dos Santos-Silva, Ricardo Salas Roldan-Filho, Pollyanna Michelle da Silva, Marx de Oliveira Lima, José Rafael da Silva Araújo, Wilson Dias de Oliveira, Suyane de Deus e Melo, Madson Allan de Luna Aragão, Thiago Henrique Napoleão, Patrícia Maria Guedes Paiva, Ana Christina Brasileiro-Vidal, Ana Maria Benko-Iseppon
The in vitro and in vivo micronucleus test is considered the gold standard for the analysis of genotoxicity. It analyzes the genotoxic potential by the frequency of nuclear changes resulting from chromosomal changes in the previous mitosis, including chromosome breaks or loss of whole chromosomes. Nuclear changes are mainly observed as micronucleus formation but also by the presence of nuclear buds and nucleoplasmic bridges (Fenech 2007), as well as the detection of apoptosis, necrosis and cytotoxicity. Regulatory agencies recommend that in vitro tests should include the step of blocking cytokinesis for the formation of binucleated cells, denominated cytokinesis-block micronucleus assay (CBMN) (EMA 2013; OECD 2016a), which allows the identification of the cells exposed to the candidate compound for one or more division cycles (Fenech 2007). The cytotoxicity (CBPI) by analyzing the number of cell cycles using CBMN assays is one of the tests recommended by international agencies (OECD 2016a; 2016b).
Hazard Characterization and Dose–Response Assessment
Published in Ted W. Simon, Environmental Risk Assessment, 2019
Genotoxicity is the ability of substances to damage DNA and/or cellular components regulating the fidelity of the genome—such as the spindle apparatus, topoisomerases, DNA repair systems, and DNA polymerases. The oldest, least expensive, and least predictive test is the bacterial reverse mutation assay, or Ames Test. The in vitro micronucleus test uses mammalian cell lines or cultures of primary human cells and looks for micronuclei or chromosomal aberrations. Micronuclei are infrequent third nuclei formed during cell division that contain chromosome fragments. The dose-dependent frequency of micronuclei suggests potential genotoxicity. In vivo genotoxicity tests are most often performed in transgenic animals and look for specific effects depending on the transgenic species.157
Benzene Carcinogenecity
Published in Muzaffer Aksoy, Benzene Carcinogenicity, 2017
The cytogenic effect of benzene was tested by Hite et al.114 by means of micronucleus test. This test is based on the detection of small chromatin particles in the cytoplasm of young erythrocytes from the bone marrow. In contrast to the trials mentioned above, the results showed a significant increase in the numbers of nuclei of polychromatic erythrocytes with micronuclei in the mice studied. Several compounds of varying chemical classes have been reported to do this in test animals, and many of these agents are to be carcinogenic.114 Lyon115 carried out the above mentioned test in rats; 0.025, 0.05, or 0.25 ml of benzene per kilogram of body weight was given to rats. The rats in the two higher dosage groups showed higher micronucleus counts than the corresponding controls.115 Siou and Canan116 performed a study of micronucleus test on mice, which were given 0.25 ml of benzene per kilogram of body weight. This trial showed that there was an increase in the number of cells with micronuclei.
Anti-hyperglycemic and genotoxic studies of 1-O-methyl chrysophanol, a new anthraquinone isolated from Amycolatopsis thermoflava strain SFMA-103
Published in Drug and Chemical Toxicology, 2021
Cheemalamarri Chandrasekhar, Hemshikha Rajpurohit, Kalpana Javaji, Madhusudana Kuncha, Aravind Setti, A. Zehra Ali, Ashok K. Tiwari, Sunil Misra, C. Ganesh Kumar
Micronucleus test at 30 h post-treatment was conducted in bone marrow cells and peripheral blood. In the bone marrow cells, Cy at 200 mg/kg induced MN by 5.16% in male and 5.80% in female mice, whereas mice injected with 0.9% NaCl (vehicle control) was significantly lesser in the percentage of MN in both male (2.89%) and female (2.72%) mice, respectively (p < 0.001) (Table 2). While comparing the induction of MN among the three groups of mice that received three different doses of OMC, at the lowest concentration (250 mg/kg) the induction of MN decreased significantly in both male and female mice when compared to Cy (p < 0.001), whereas at two higher doses of OMC (500 and 1000 mg/kg), the induction of MNs were almost similar to Cy (positive control). Micronuclei observed in peripheral blood were found to be lesser in number as compared to the micronuclei from bone marrow cells since the grossly affected cells might be eliminated before reaching the blood circulation. In the Cy treated group, the induction of micronuclei was 4.11% and 4.33% in male and female mice, respectively; whereas, there were significantly lesser number of micronuclei observed among the mice that received three different doses of OMC (Table 3). Similarly, some researchers found differences in the MN induction between male and female mice when treated with different toxicants (Shizuyo 1986, Kliesch and Adler 1992, Gebel et al.1997, Hamada et al.2003).
Genotoxic action of Luna Experience-SC 400 fungicide on rat bone marrow
Published in Biomarkers, 2019
Ayla Çelik, Gizem Güler, Cuma Aktaş, Serap Yalin
Micronucleus test method has been used to evaluate the potential effects of chemicals for decades in many researches in in vitro and in vivo studies in different living systems (Çelik et al.2003, 2005, Çelik and Kanık 2006, Çavaş 2011) for genotoxicity. The single cell gel electrophoresis assay (SCGE) or alkaline comet assay provides the opportunity evaluating the DNA damage responses of individual cells exposed to DNA damaging agents and visualizes DNA migration within nucleus embedded in agarose (Singh et al.1988). The depth of migration is related to the greatness of single strand breaks in damaged DNA (Collins et al.1997). Thus, the aim of this study was to evaluate, for the first time, the genotoxic and clastogenic/aneugenic potential of Luna Experience SC 400 fungicide in rat bone marrow.
Assesment of hematotoxic, oxidative and genotoxic damage potentials of fipronil in rainbow trout Oncorhynchus mykiss, Walbaum
Published in Toxicology Mechanisms and Methods, 2021
Arzu Uçar, Veysel Parlak, Aslı Çilingir Yeltekin, Fatma Betül Özgeriş, Özge Çağlar, Hasan Türkez, Gonca Alak, Muhammed Atamanalp
The micronucleus test is an ideal genotoxic monitoring technique that uses aquatic organisms to assess the genotoxicity of pollutants in water. This method is suitable for determining the clastogenic and aneugenic factors in in vivo and in vitro trials (Al-Sabti and Metcalfe 1995). Researchers used the micronucleus test to detect and predict the biological effects of pollutants on genotoxic damage in fish (Ergene et al. 2007; Parveen and Shadab 2012). They reported that abnormalities in fish erythrocytes may be related to cytotoxicity, cell division, genotoxicity or mutagenicity (Da Silva Souza and Fontanetti 2006).