Determination of effects of different concentrations of the crude extract of maggots on bacterial membrane permeability by uorescence probe technique
The co-cultured broth of the crude extract of maggots and E. coli was centrifuged, washed with sterile normal saline, re-suspended with 1 mmol/L of Fluo-3/AM, and adjusted to a nal concentration of 3 μmol/L. After incubation and centrifugation (10000 g, 5 min), the supernatant was discarded and the pellet was washed and re-suspended in 3 mL of normal saline. The sample was scanned between 380 and 430 nm using 405 nm as the excitation wavelength, and an absorption peak was detected at 408 nm. Then, changes in intracellular calcium were monitored with the excitation wavelength set at 408 nm. The rate of membrane permeability change was calculated as [(sample uorescence intensity - blank fluorescence intensity)/fluorescence intensity of blank] × 100%. Gentamicin was used as a control.