Experimental Study into the Embryonic Development of Common Toad (Bufo bufo): Methodological Aspects

Abstract

The embryonic and larval stages of amphibian development are promising model objects for developmental biology, experimental biology, and medicine. However, the existing methods of laboratory research do not take into account the biological features of model amphibian species. In addition, not enough attention is paid to standardizing the experimental conditions and minimizing the experimenter’s influence on their results. The fact that the experimental research methodology developed for one amphibian species cannot be used for similar research on another species without significant modification with consideration of the biology of this object is also not accounted for. The article summarizes the results of many years of research devoted to the study of factors that influence the results of laboratory experiments on the embryonic developmental stages of the common toad Bufo bufo. By the example of this species, new methodological approaches to laboratory research have been developed, allowing consideration for the species’ particular biological features, minimization in the heterogeneity of the effects from previously uncontrolled factors, and standardizing the conditions for conducting experiments. Maintaining the temperature at 15–17°C throughout the experiment, taking regular measurements at regular intervals (8 h), and conducting each test at two values of the initial egg density (recommended 30 and 120 eggs in a single string per standard aquarium) is recommend. When setting up experiments, one should take into account the influence of not only “bulk” but also “surface” and “linear” densities. It is also shown that any additional effects of the experimenter on the embryos associated with the removal of dead individuals performed during the experiments can have a significant impact on the result; therefore, such effects should be minimized.