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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
A second in vitro and in vivo test widely used in the analysis of candidate antimicrobial compounds is the chromosomal aberration test, by analyzing both structural and numerical changes scored in metaphase cells (FDA 2012; EMA 2013; Sekizawa et al. 2017). Structural chromosomal aberrations include chromosome gaps, breaks, deletion and other rearrangements like duplications, dicentrics, rings, isochromosomes, inversions and translocations. While the numerical changes result in disturbances or interferences in the chromosomal number at cell division, that can lead to cells bearing aneuploidy or/and polyploidy (Mosesso et al. 2019).
Radiation Carcinogenesis: Tissue Culture Model
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
Based on numerous cellular and molecular biology studies, the following hypotheses of cancer have been proposed: Activation of protooncogenes.3,4Loss of antioncogenes.5Infection with certain viruses.6Substitution of normal promoters of protooncogenes with strong promoters of viruses.7Chromosomal aberrations.8b
The Effect of Dose Rate, Fractionation and Post-Irradiation Repair
Published in K. H. Chadwick, Understanding Radiation Biology, 2019
There is an explanation for these results in the model. The explanation lies in the Resnick recombination repair process for DNA double strand breaks. In all the figures shown in Chapter 4 for the formation of chromosomal aberrations from the repair of a DNA double strand break, two different possible resolutions of the repair process were illustrated. If the Holliday hetero-duplex was properly resolved, then the broken double helix was restored. This accounts for both the reduction in chromosomal aberration yield and the mutation frequency. If the Holliday hetero-duplex was incorrectly resolved, then an aberration and, most probably, a mutation would be formed. It seems that delayed plating in a stationary state offers the cell more time to resolve the Holliday hetero-duplex correctly. Immediate plating possibly rushes the repair of the double strand break so that the cell sometimes fails to resolve the Holliday hetero-duplex properly.
Early flowering, good grain quality mutants through gamma rays and EMS for enhancing per day productivity in rice (Oryza sativa L.)
Published in International Journal of Radiation Biology, 2021
Vinithashri Gautam, Manonmani Swaminathan, Manoharan Akilan, Anand Gurusamy, Meena Suresh, Bhuvaneswari Kaithamalai, A. John Joel
Both genotypic differences and modes of action of different mutagens contribute to variation in the spectrum of mutants generated. Kharkwal (2000) quoted the differences in frequency and spectrum of viable mutations induced by various mutagens due to genetic differences in varieties. Putting forth in a theoretical way, any gene responsible for an agronomic trait is mutable, hence a wide spectrum of viable mutations can be generated in a mutation experiment. The occurrence of these macro-mutations can be attributed to chromosomal aberrations. Mutations in recessive genes occur when there are deficiency, duplications, or point mutations due to mutagens. Chlorophyll mutants and morphological mutants show up in M2 generation while they are not observed in M1 generation and this explains the recessive nature of those mutations. Mutagenic effectiveness and efficiency represent the features of mutagens and sheds light on their utility in crop improvement. Mutagenic effectiveness gives the measure of the frequency of mutations induced by a unit dose of mutagen and efficiency gives the info on biological damage (Konzak, 1965; Nilan, 1965). The results of gamma rays and combination treatments in M2 and M3 generation revealed that the combination treatments were found more effective and efficient in causing variability than gamma rays alone.
Oxidative protein modification and chromosomal instability among type 2 diabetics in Osogbo, Nigeria
Published in Alexandria Journal of Medicine, 2021
O.O. Olaniyan, O.O Odewusi, H.B Osadolor
Due to increased relative risk of morbidity and mortality among individuals with diabetes as compared with apparently healthy non-diabetes controls, diabetes can be viewed as a premature aging syndrome that affects the overall metabolic shift leading to genotoxic stress and loss of chromosomal integrity [8]. Alterations in genomic system occur when the process of oxidative DNA lesions/damage overwhelms the DNA repair mechanism, leading to accumulation of unrepaired damaged DNA in the system. Thus, chromosomal aberration can be described as the microscopically visible part of a wide spectrum of DNA changes generated by different repair mechanisms of DNA double strand breaks and it represents the biological consequences of human exposure to either ionizing or genotoxic agents or both [9]. Chromosomal aberrations can either be a numerical abnormalities (missing of whole chromosome or addition of extra chromosome to the normal pair) or structural abnormalities (when part of an individual chromosome is missing/extra switched to another chromosome/turned upside down) [10]. Structural chromosomal aberration (sCA) is a product of breakage and incorrect rejoining of chromosomal segments that resulting in varieties of disease conditions. Structural chromosomal aberration can either be balanced (the complete chromosomal set is still present after being rearranged, e.g. inversions, translocations) or unbalanced (after the rearrangement the complete chromosomal set is either missing or having an addition, e.g. deletions, duplications, insertions) [11].
Role of inflammation in the malignant transformation of pleural mesothelial cells induced by multi-walled carbon nanotubes
Published in Nanotoxicology, 2020
Xiaopei Huang, Yijun Tian, Wenjing Shi, Jikuai Chen, Lang Yan, Lijun Ren, Xiaofang Zhang, Jiangbo Zhu
The genotoxicity of MWCNTs on macrophages and Met 5A cells was detected using a chromosome aberration assay. The groups were as follows: positive control group cyclophosphamide + Met 5A) and negative control group (DMSO + Met 5A). The other groups were: macrophages + Met 5A; MWCNTs + Met 5A; MWCNTs + macrophages + Met 5A. The final concentration of MWCNTs was 0.1 µg/mL with an exposure time of three months. Results demonstrated that chromosomal aberrations in the negative control group, positive control group, macrophages + Met 5A group, MWCNTs + Met 5A group, and MWCNTs + macrophages + Met 5A group were 1.0, 14.6, 0.8, 2.8, and 5.0%, respectively. Compared to the negative control group, the chromosome aberration rate of the MWCNTs + macrophages + Met 5A group and the MWCNTs + Met 5A group increased significantly (p < 0.05). Similarly, compared to the MWCNTs + Met 5A group, the chromosome aberration rate of the MWCNTs + macrophages + Met 5A group increased significantly (p < 0.05) (Table 3). The types of chromosomal aberrations are mainly breakage, chromosomal ring, triploidy, polyploidy, and so forth. Typical pictures depicting normal and aberrant chromosomes are shown in Figure 3.