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Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
As we will discuss in Chapter 6, immune responses are costly to mount, and heavy investment in defenses can limit the resources available for other key functions such as reproduction. This general constraint would certainly apply to invertebrates too. Consequently, it is not surprising that animals resort to particular behaviors to limit their exposure to parasites or, in the context here, to supplement their immune responses. One example is provided by the larvae of Drosophila melanogaster, which consume yeast developing in rotting fruit. The larvae are susceptible to attack by parasitoid wasps (species of Leptopilina), the females of which inject their eggs into the fly larvae. The developing wasp larvae then consume and eventually kill the fly larvae. Upon wasp attack, fly larvae seek out food containing ethanol, which proves to be an advantageous drinking habit in this case. Wasp larvae are more sensitive to the effects of ethanol than the fly larvae, and ethanol supplementation in the larval fly diet reduces wasp infection success, increases killing of wasp larvae and promotes survivorship of larval flies without the fly larvae having to mount typical defense responses.
Optical Nanoprobes for Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
In vivo imaging of live animal with NIR photoluminescence was demonstrated successfully [156]. Drosophila larvae was fed with food containing SWCNTs and imaged by NIR fluorescence microscope. The biodistribution of SWCNTs in live larvae was observed by the fluorescence signals from the nanotube. Biocompatible SWCNTs with high QY are a vital goal to attain. Biocompatible SWCNTs were developed by sonication of SWCNTs with sodium cholate and surfactant exchange to generate phospholipid–PEG for in vivo imaging [157]. The exchange procedure was superior to direct sonication with phospholipid– PEG, because the former resulted in less damage to the nanotubes and improved the QY. SWCNTs obtained after exchange procedure known as exchange SWCNT conjugates were studied as NIR photoluminescence contrast agents for in vivo imaging in mice. They demonstrated whole-animal in vivo imaging at a relatively low dose of contrast agents and the imaging small vessels inside the tumor.
The science of ageing
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
The programmed ageing theory is actually three intertwined theories: programmed longevity, the endocrine theory of ageing and the immunological theory of ageing. These three theories are believed to run concurrently and support the utilitarian hypothesis that we age (and eventually die) to benefit the species as a whole. The programmed longevity theory suggests that throughout our lives from the moment of conception, various genes are turned on and off to cope with certain biological stresses. One piece of evidence for this theory is that within a species there is a relatively large range of individual lifespans; however, a maximum expected lifetime is relatively easy to predict. This contradicts some theories of ageing suggesting that as organisms age, they gradually decline, as some organisms (such as the fruit fly Drosophila) frequently die after a set life span despite displaying no overt signs of slowing down. It is suggested that having a stable genome as opposed to a wide genetic variability may indeed be a defining factor in the age somebody can hope to live to. It has been hypothesised that genes are turned on and off to survive biological and ecological stresses; however, most of us in the developed world are rarely severely physiologically stressed, with relatively easy access to food, shelter and medicine. One must consider ageing as therefore a genetic domino effect and that there is a clock ticking within each and every one of our cells with cell death being a pre-programmed end of a long chain of events throughout our lifetime.
Evaluating Water bitter leaf (Struchium sparganophora) and Scent Leaf (Ocimum gratissimum) extracts as sources of nutraceuticals against manganese-induced toxicity in fruit fly model
Published in Drug and Chemical Toxicology, 2023
Adedayo Oluwaseun Ademiluyi, Opeyemi Babatunde Ogunsuyi, Josephine Oluwaseun Akinduro, Olayemi Philemon Aro, Ganiyu Oboh
The fruit fly (Drosophila melanogaster), is one of the most studied eukaryotic organisms and has made fundamental contributions to different areas of biology. It has also gained appreciation as a useful animal model of human diseases. Comparative genomic studies estimate that up to 75% of the human genes implicated in diseases are expressed in Drosophila (Ugur et al. 2016). The similarity between human and Drosophila genomes is not limited to only genetic, but also numerous conserved biological mechanisms. The Drosophila genome is smaller in size and has a smaller number of genes compared to the human genome, which facilitates genetic studies. The fruit fly Drosophila melanogaster has proven to be a powerful platform with plenty of amenable genetic techniques to investigate the mechanism of human neurodegenerative diseases (Bilen and Bonini 2005).
Adverse effects of textile dyes on antioxidant enzymes and cholinesterase activities in Drosophila melanogaster (Oregon R+)
Published in Drug and Chemical Toxicology, 2022
Shaista Rahimi, Mahendra P. Singh, Jeena Gupta
Drosophila melanogaster is a widely used in vivo model organism for toxicity testing because it possesses many advantages. The maintenance of Drosophila is easy under laboratory conditions and its short generation-time allows for quick evaluations. Furthermore, the metabolic activity of Drosophila genome is sequences and more than 75% gene homology with mammalian system and more than 50% disease related genes are homologous to human. In the present study, we have evaluated the toxic effect of textile disperse dyes on acetylcholine esterase enzyme by in silico molecular docking studies and checked its pattern of change in vivo animal model i.e., Drosophila melanogaster (Oregon R+). Further, we have judged the activity of Xanthine oxidase and other antioxidant enzymes like SOD, CAT and MDA in third instar Drosophila larvae.
Recent developments in in vitro and in vivo models for improved translation of preclinical pharmacokinetics and pharmacodynamics data
Published in Drug Metabolism Reviews, 2021
Jaydeep Yadav, Mehdi El Hassani, Jasleen Sodhi, Volker M. Lauschke, Jessica H. Hartman, Laura E. Russell
Although it is not appropriate to completely replace in vivo experiments using alternative models, there are useful applications for lower invertebrate models such as zebrafish, as well as invertebrates C. elegans and Drosophila in drug discovery. There is general agreement that these models experience less stress and suffering compared to traditional models including rodents, and there are additional benefits to employing these models such as reduced cost, small size, and rapid development. Zebrafish have 70% genetic homology to humans compared to 83% homology observed between humans and mice (Howe, Clark, et al. 2013), thus there is sufficient genetic overlap to assess certain liabilities including toxicity prior to testing in rodents. However, evaluation of pharmacokinetics in these models is limited; zebrafish are quite small, and quantification of internal drug concentrations is rarely achieved, which is key to understanding the PK of a molecule. Drosophila have ∼75% genetic similarity to humans and their rapid propagation makes them easy targets for genetic knockout using technologies including CRISPR/Cas9. Clear caveats of using Drosophila, however, include their differing physiology relative to humans. Interesting studies including the creation of zebrafish liver microsomes that express human CYP3A4 (humanized zebrafish; Poon et al. 2017) are working toward better recapitulating metabolism using alternative models, and we look forward to upcoming research into improved PK and PD assays using alternative models.