Follow a Bacillus subtilis colony as it goes through the lag, log, stationary, and death phases of growth
Follow a Bacillus subtilis colony as it goes through the lag, log, stationary, and death phases of growth
Bacterial colonies progress through four phases of growth: the lag phase, the log phase, the stationary phase, and the death phase.
Video © Encyclopædia Britannica, Inc.; still photos A.W. Rakosy/Encyclopædia Britannica, Inc.
Transcript
This generalized curve demonstrates the phases in the growth of bacterial colonies.
In the log phase, cell numbers increase in a logarithmic fashion, each cell generation occurring in the same time interval as the preceding one.
A Bacillus subtilis bacterial colony appears to be in the log phase of growth after being kept at 37 degrees Celsius for 18 to 24 hours.
In the stationary phase of bacterial growth, some cells continue to divide and others begin to die, but the size of the colony’s population remains constant. At 48 hours, the Bacillus colony exhibits signs of this phase.
Finally the bacterial growth reaches its death phase, in which the death of cells in the population exceeds the formation of new cells. At 96 hours, Bacillis subtillis has reached this phase, as evidenced by its shriveling appearance.
In the log phase, cell numbers increase in a logarithmic fashion, each cell generation occurring in the same time interval as the preceding one.
A Bacillus subtilis bacterial colony appears to be in the log phase of growth after being kept at 37 degrees Celsius for 18 to 24 hours.
In the stationary phase of bacterial growth, some cells continue to divide and others begin to die, but the size of the colony’s population remains constant. At 48 hours, the Bacillus colony exhibits signs of this phase.
Finally the bacterial growth reaches its death phase, in which the death of cells in the population exceeds the formation of new cells. At 96 hours, Bacillis subtillis has reached this phase, as evidenced by its shriveling appearance.