Cellular elongation of Vibrio cholerae by the treatment of antibiotics : part 2 destiny of the elongated cell body

Sensitivity of Vibrio cholerae NIH35A3 to cephalein (CEX) was examined, and concentrations of CEX suitable for the elongation were determined. Normal or elongated cells of V. cholerae were inoculated on semisolid heart infusion agar layered on glass slides containing CEX in various concentrations (0-100μg/ml). Morphological changes of bacterial cells were observed under differential interference microscopy at the intervals of 30 min. or 1 hour. The results obtained are as follows : 1. The concentrations of CEX suitable for elongation were ranged from one half to a quarter of the minimum inhibitory concentration. 2. When the elongated cell bodies were transferred to the medium without CEX, they began dividing and propagating from the terminal portion. 3. At the subinhibitory and mininum inhibitory concentrations of CEX, the normal and elongated cell bodies did not divide, but showed further elongation. A partial swelling of the cell body also appeared. 4. At high concentration of CEX, spherical dobies appeared, and cell lysis eventually occurred.