Evaluation of Epigenetic and Radiomodifying Effects during Radiotherapy Treatments in Zebrafish

Radiotherapy is still a long way from personalizing cancer treatment plans, and its effectiveness depends on the radiosensitivity of tumor cells. Indeed, therapies that are efficient and successful for some patients may be relatively ineffective for others. Based on this, radiobiological research is focusing on the ability of some reagents to make cancer cells more responsive to ionizing radiation, as well as to protect the surrounding healthy tissues from possible side effects. In this scenario, zebrafish emerged as an effective model system to test for radiation modifiers that can potentially be used for radiotherapeutic purposes in humans. The adoption of this experimental organism is fully justified and supported by the high similarity between fish and humans in both their genome sequences and the effects provoked in them by ionizing radiation. This review aims to provide the literature state of the art of zebrafish in vivo model for radiobiological studies, particularly focusing on the epigenetic and radiomodifying effects produced during fish embryos’ and larvae’s exposure to radiotherapy treatments.

The Toxic Effect of Cu and CuO Nanoparticles on Euplotes Aediculatus

Toxicology tests were carried out by choosing Cu nanoparticles (CuNPs) and CuO nanoparticles (CuONPs) as experimental materials and Euplotes aediculatus as the experimental organism. To investigate the toxicity effect and mechanism of two NPs on E. aediculatus, we determined antioxidant enzyme activity and observed morphologic changes using optical and electron microscopes, combined with the Fourier infrared spectrum technique. The results showed that the 24 h-LC50 of CuNPs and CuONPs was 0.46 µg/L and 1.24×103 µg/L. The movement ability of cells was decreased and surface cilia gradually shed with CuNPs and CuONPs at 24 h-LC50. In addition, the cell body swelled and finally ruptured. There were varying extents of damage to the nucleus and mitochondria. With CuNPs, disappearance of nucleoli and condensation of chromatin were observed, while the mitochondria were wrinkled in an irregular shape and cristae were partially fractured. With CuONPs, changes of nucleus were not obvious, and the mitochondria were merely irregular. While neither CuNPs nor CuONPs had major effect on the ultrastructure of the membrane, some functional groups were oxidized with CuNPs, e.g. PO2-, C-O-C, δ(COH) of carbohydrates. The 24 h-EC50, 48 h-EC50 and 72 h-EC50 of CuNPs on E. aediculatus were 2.10×10-3 µg/L, 7.92×10-4 µg/L and 2.77×10-4 µg/L. The EC50 of CuONPs in same period was 7.20 µg/L, 0.86 µg/L and 0.19 µg/L. The above concentration of CuNPs and CuONPs could increase the activities of SOD, CAT and GPx, which were dose-dependent. The above results indicate that CuNPs and CuONPs inhibited reproduction and caused death. CuNPs were more toxic to E. aediculatus and more destructive to cell structure. Oxidative stress and destruction to cell structures may be toxic mechanisms. The E. aediculatus was more sensitive to CuNPs or CuONPs, and the value of 24 h-LC50 was much lower than other organisms, so it can be recommended as an indicator for early monitoring in freshwater environment.

Developing Tadpole Xenopus laevis as a Comparative Animal Model to Study Mycobacterium abscessus Pathogenicity

Mycobacterium abscessus (Mab) is an emerging, nontuberculosis mycobacterium (NTM) that infects humans. Mab has two morphotypes, smooth (S) and rough (R), related to the production of glycopeptidolipid (GPL), that differ in pathogenesis. To further understand the pathogenicity of these morphotypes in vivo, the amphibian Xenopus laevis was used as an alternative animal model. Mab infections have been previously modeled in zebrafish embryos and mice, but Mab are cleared early from immunocompetent mice, preventing the study of chronic infection, and the zebrafish model cannot be used to model a pulmonary infection and T cell involvement. Here, we show that X. laevis tadpoles, which have lungs and T cells, can be used as a complementary model for persistent Mab infection and pathogenesis. Intraperitoneal (IP) inoculation of S and R Mab morphotypes disseminated to tadpole tissues including liver and lungs, persisting for up to 40 days without significant mortality. Furthermore, the R morphotype was more persistent, maintaining a higher bacterial load at 40 days postinoculation. In contrast, the intracardiac (IC) inoculation with S Mab induced significantly greater mortality than inoculation with the R Mab form. These data suggest that X. laevis tadpoles can serve as a useful comparative experimental organism to investigate pathogenesis and host resistance to M. abscessus.

Monohibridization with Different Media Treatments on Fruit Flies (Drosophila melanogaster)

Drosophilla melanogaster is a modern experimental organism in the field of genetics because it has different phenotypic characters and looks real, easy to get, cheap (can be bred in bottles containing only fermented banana media) and has a breeding time that is not too long (2 weeks with maturation time) initial sexual ie 7 hours after exiting the pupa). This study aims to differentiate male and female fruit flies, create growth media for fruit fly culture and observe the phenotype ratio of F1 monohibrid crosses. The method used is the crossing of fruit flies by inserting male fruit flies and female fruit flies into a jam jar containing the medium using fermipan and not using fermipan. The phenotype and sex of fruit flies are formed from crossing of fruit flies. The results obtained in the form of fruit flies at most can grow on agar media and added corn flour with yeast. The medium needed by fruit flies to grow is a medium rich in protein and not much water dense. The media with corn flour is strong enough to resist thawing caused by larval activity, so that many larvae are found. Based on these conclusions, it can be continued observation of the fruit fly's politen chromosome in the next research.