When dissolving agarose in a microwave oven, the gel may boil and overflow from the triangular conical flask. During microwave heating, the gel may boil violently，

1) The total liquid volume should not exceed 50% of the capacity of the conical flask；

2) Set the adhesive solution to medium heat for more than 2%；

3) When the gel solution boils violently, stop heating, remove the conical flask, wear heat-resistant gloves, carefully shake the conical flask, and then heat it again until the gel solution boils until it becomes clear, ensuring complete dissolution of the agarose.

Agarose gel electrophoresis is a common technique for the separation and purification of DNA fragments. The DNA sample is added to the sample hole of a porous support medium (agarose gel) containing electrolyte and placed on the electrostatic field. Due to the presence of negatively charged phosphate residues on both sides of the double helix skeleton of DNA molecules, they move towards the positive electrode in an electric field. At a certain electric field strength, the migration speed of DNA molecules depends on the molecular sieve effect. The swimming speed of DNA fragments with different relative molecular weights varies, so they can be separated based on the size of the DNA molecule. Gel electrophoresis can not only separate DNA with different molecular weights, but also separate DNA molecules with the same relative molecular weight but different configurations.

Agar is a natural polysaccharide mainly composed of agarose (about 80%) and agarose gel. Agarose is a neutral substance composed of galactose and its derivatives, without charge, while agarose gel is a strong acidic polysaccharide containing sulfate and carboxyl groups. Due to the charge of these groups, it can produce strong electroosmotic phenomena under the action of an electric field. In addition, sulfate groups can interact with certain proteins, affecting the electrophoresis speed and separation efficiency.

From the formula of electrophoretic mobility, it can be seen that there are many factors that affect electrophoretic separation. The following briefly discusses some of the main influencing factors.

In 1809, Russian physicist Tsar ейсе first discovered the phenomenon of electrophoresis. He inserted positive and negative electrodes with glass tubes into wet clay, and after applying voltage, found that the original water layer in the positive glass tube became turbid, that is, negatively charged clay particles moved towards the positive electrode, which is the phenomenon of electrophoresis.

G418 is an aminoglycoside antibiotic commonly used for resistance screening in molecular genetic experiments. It produces toxins in prokaryotic and eukaryotic cells, including bacteria, yeast, plants, and mammalian cells, as well as protozoa and worms, by inhibiting the genes of transposons Tn601 and Tn5. When the neo gene is integrated into eukaryotic cell DNA, it can initiate the transcription of the sequence encoded by the neo gene into mRNA, thereby achieving efficient expression of resistance products, enabling cells to acquire resistance and grow in selective culture media containing G418. The selection characteristic of G418 has been widely applied in gene transfer, gene knockout, resistance screening, and transgenic animals. The mechanism of action of aminoglycoside antibiotics is that aminoglycoside antibiotics have a strong cytotoxic effect, mainly acting on the ribosomes of cells and inhibiting protein synthesis.