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Animal biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
Researchers always wanted an ideal situation where they can induce humanlike disease conditions and try to reverse it by drug therapy. In particular, model organisms are widely used to explore potential causes and treatments for human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms and the conservation of metabolic and developmental pathways and genetic material over the course of evolution. Studying animal models can be informative, but care must be taken when generalizing from one organism to another. In the next section, we will study some of the most widely used animal models in details.
Distribution, sources and toxicity of polycyclic aromatic hydrocarbons in Liuxi River, China
Published in Chemistry and Ecology, 2022
Wang Min, Tian Lei, Sun Jingxin, Yutong Zhang, Zhai Hongqin, Li Dong, Wan Lin
With recombinant Escherichia coli (E.coli K12, MG1655) as the model organism, the toxic effects of PAHs were investigated through toxicological genomics method. The E.coli gene library has five types of stress: oxidative stress, DNA stress, protein stress, membrane stress and general stress reaction. The experimental process is as follows. The strain was placed in a 96-well plate for overnight culture at 37 °C, and the strain and the culture medium were diluted in a certain proportion and transferred to a 384-well culture plate (Costar) for dark culture at 37 °C for 5-6 h until the strain reached the early exponential growth stage. Different concentrations of PAHs were added into the stain. Then the pore plates were placed into a micropore plate reader (Cytation5, USA Bio-Tek) to measure the cell growth (optical density) and fluorescence intensity (excitation wavelength: 485 nm, emission wavelength: 528 nm) every 5 min for 2 h. Three groups of parallel samples were set in the experiment.
Behavioral and Oxidative Stress Responses of Earthworm, Nsukkadrilus mbae (Segun 1976), Exposed to Lead and Cadmium: A Preliminary Investigation
Published in Soil and Sediment Contamination: An International Journal, 2021
Ifeanyi O. Aguzie, Kenechukwu D. Enekwe, Ijeoma J. Emekekwue, Chinweike N. Asogwa, Grace C. Onyishi, Ndubuisi S. Oluah, Felicia N. Ekeh, Christopher D. Nwani
The earthworm N. mbae was able to detect and avoid Pb and Cd-contaminated soil, and response depended on metal concentration. Burrowing activities of the earthworm were also affected by the contaminants such that the earthworm’s time to start of burrowing, time to completion of burrowing, and the time interval between both events were significantly extended in Pb- and Cd-contaminated soil compared to the uncontaminated soil. Pb and Cd also induced oxidative stress on short- (2-d) and long-term (d-30) in N. mbae even though the effect was difficult to detect on long-term using CAT, SOD and GPx. However, GSH and MDA were sensitive on both short- and long-term. Based on this study which is the first report on the behavior of N. mbae on exposure to Pb and Cd contaminants, the species served as a suitable model organism. The metals induced oxidative stress in the earthworm which eventually led to mortality, but the earthworm appeared relatively tolerant at Pb and Cd concentrations of 20 µg/g and 2 µg/g, respectively. However, there is need to explore the impact of these metals on N. mbae using static renewal or non-renewal systems allowing more than sufficient feed, and using gut wall homogenates instead of whole organism to assess oxidative stress and its mechanism especially considering the drop in CAT activity in the control group from this preliminary investigation. It would be necessary to accompany such with quantification of metal accumulation in earthworm tissues.
Toxicity and differential oxidative stress effects on zebrafish larvae following exposure to toxins from the okadaic acid group
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Diego Figueroa, Ailen Signore, Oscar Araneda, Héctor R. Contreras, Miguel Concha, Carlos García
Zebrafish (Danio rerio) is an important model organism for the study of aquatic toxicity, as well as in the evaluation of water quality (Martínez-Sales et al. 2015). Consequently, it is an attractive and widely used model organism for developmental biology, biomedical, genetic, and toxicology studies (Abe et al. 2017; Barros et al. 2020; Chatla et al. 2016; Olson et al. 2018; Wang et al. 2019, 2017). Further, the use of this model organism (Danio rerio) enables one to establish a sequence of biological events produced by stress, and, the observed subcellular changes might indicate whether damage occurs prior to irreversible effects (Ribas and Piferrer 2014). Thus, determination of oxidative damage produced by chemical compounds might clarify the compromised physiological state of exposed organisms.