What does mycoplasma contamination of cells mean?

Mycoplasma-contaminated cells refer to the situation in which mycoplasma infection and contamination occur during the bacterial culture process. This is a global problem in the process of bacterial culture and often affects the results of the inspection. Mycoplasma is the smallest pathogen and belongs to prokaryotes. When culturing bacteria, if you are not careful, mycoplasma may infect cells. So we must pay attention to this aspect.

Introduction to pollution Mycoplasma is a prokaryotic organism with a size of only 0.2~0.3 um, no cell wall, and can pass through general filtration membranes (0.22-0.45 um). During cell culture, the incidence of mycoplasma infection reaches 63%. Therefore, mycoplasma contamination during cell culture is a global problem. When cells (especially cultured cells) are contaminated with mycoplasma, the expression of DNA, RNA and protein in the cells changes, but the growth rate of the cells is generally not significantly affected. Therefore, mycoplasma contamination of cells is generally difficult to detect.

Detection Methods

Generally, different methods are used for detection according to the different types of mycoplasma. The commonly used detection methods at present are: 1. Kit detection method: There are currently kits specifically for mycoplasma detection, which can be used for detection using cell droplets. 2. Observe the morphology and growth characteristics of cells: When mycoplasma contamination is serious, growth may slow down, the pH of some culture media may become significantly acidic, and cytopathic effects may occur. Mycoplasma contamination can be detected in turn. However, in some cases, the pathological characteristics caused by mycoplasma contamination are similar to those of viral infection, so an accurate diagnosis cannot be made. 3. Isolation and culture method: Most mycoplasmas can produce unique typical colonies. Therefore, the method can be tested carefully one by one. It is accurate and reliable, but it takes a long time and the sensitivity is not high enough. 4. DNA binding fluorescein staining method: Use fluorescent dye (bisbenzimide, Hoechst 33258) to detect mycoplasma contamination. The fluorescent dye will bind to the Adenosine-Thymidine (AT) rich region of DNA. Since the AT content in mycoplasma DNA is the majority (55-80%), it can be stained and detected. After staining, cells contaminated with mycoplasma can be seen outside the cell nucleus and around the cells with many small fluorescent dots of uniform size, which are the DNA of mycoplasma, proving the presence of mycoplasma contamination.