Figure 2From: Amyloid-beta peptide degradation in cell cultures by mycoplasma contaminantsDegradation of extracellular Aβ by mycoplasma contaminants. (A) PCR amplification of mycoplasma genomic DNA was performed with an internal negative control template (Control -), a positive control template of M. orale genomic DNA (Control +), or with medium from mycoplasma-positive HEK293 cell cultures (Mycoplasma+ Medium). Assay was carried out according to manufacturer's instructions (MycoSensor PCR Assay Kit, Stratagene). The changes in intensity of the internal control amplification are due to competition with the mycoplasma-specific PCR. (B) Medium from mycoplasma-positive cells was centrifuged at 1000 × g for 10 min to pellet the cell debris. Conditioned medium from APP-transfected HEK293 cells was diluted 1:1 with either fresh medium (Control DMEM), or with unfiltered (Mycoplasma+ Medium) or 0.2 μm filtered [Mycoplasma+ Medium (Filtered)] medium from mycoplasma-positive cells. The resulting mixtures were incubated at 37°C for the indicated periods of time. sAPPα and Aβ were analyzed by WB, as described in Figure 1B.Back to article page