preview

Photosynthesis Lab Report

Satisfactory Essays

2. In this experiment the effects of exogenously applied RA on early neural development of zebrafish embryos were observed. It included immunocytochemical and histochemical analysis of the developing embryos along with quantitative analysis of their anatomy. Knowing that RA is a positional signaling molecule, they wanted to observe the changes that occur to the anatomy of the zebrafish embryos at different stages when exposed to RA. Embryos at 50% epiboly and midgastrula stage were exposed to RA concentrations ranging from 10-9¬ to 10-6 M, and embryos at early and late gastrula stages were exposed to RA concentrations of 10-7 M. For immuniohistochemical analysis, antibodies 4D9, HNK-1, and MZ15 were used, HNK-1 was used as a marker of neural crest migration, MZ15 in labeling notochord tissue, and 4D9 in identifying engrailed …show more content…

The RA treated embryos at 50 % epiboly were observed to have affected brain structures that are derived from the neural tube and affected peripheral neural structures in the head derived from the neural crest and placods. Quantitative analysis of the anterior structures via acetylcholinesterase stain showed that 10-9¬ M RA has little to no effect on the embryo whereas 10-8 and 10-7 M RA give rise to discernable abnormalities. 10-6 M RA was essentially toxic. At 10-8 and 10-7 M concentrations of RA, the position of the anterior margin otocyst with respect to the eye is roughly halved, and the notochord also moves more anteriorly. There are no significant changes in the development of the midbrain caudal hindbrain, and otocyst, however the rhombomeres cranial to the otocyst are abnormal in most cases. With a RA concentration of 10-6 M, no structures could be discerned in the head, nearly all features were under/not developed, and the forebrain, midbrain, and hindbrain neurons were not differentiated. Eyes and otocysts were not developed and the tail was also

Get Access