Do the bacteria proliferate during Lag-phase?

[Eagle9]

In various sources I found the different opinions about this. Which one is true?

During lag phase, bacteria adapt themselves to growth conditions. It is the period where the individual bacteria are maturing and not yet able to divide. During the lag phase of the bacterial growth cycle, synthesis of RNA, enzymes and other molecules occurs.

http://en.wikipedia.org/wiki/Bacterial_growth

They say bacteria do not proliferate during lag-phase.

In the lag phase, the organisms do not increase significantly in number, but they are metabolically active—growing in size, synthesizing enzymes, and incorporating various molecules from the medium. During this phase the individual organisms increase in size, and they produce large quantities of energy in the form of ATP.

They say bacteria do proliferate during lag-phase.

Cultured cells, particularly when grown as a monolayer attached to a substrate, will go through are producible growth cycle following subculture (1). The phases normally defined are(1) the lag phase, before the culture starts to proliferate.

They say bacteria do not proliferate during lag-phase.

When a microbial culture is inoculated into a fresh medium, growth usually begins only after a period of time called the lag phase. This interval may be brief or extended, depending on the history of the inoculum and the growth conditions. If an exponentially growing culture is transferred into the same medium under the same conditions of growth (temperature, aeration,and the like), there is no lag and exponential growth begins immediately.
Lag phase - The period after inoculation of a culture before growth begins.

They say bacteria do not proliferate during lag-phase.

The first two stages are the lag phase,where growth is slow at first, bacteria become “acclimatized” to the new environmental conditions to which they have been introduced (pH, temperature, nutrients, etc.), and no significant increase in numbers with respect to time, and the log phase, where the number of bacteria doubles every few minutes.

They say bacteria do proliferate during lag-phase.

For a while, the number of cells changes very little because the cells do not immediately reproduce in a new medium. This period of little or no cell division is called the lag phase, and it can last for1 hour or several days.

During the lag phase, there is little or no change in the number of cells, but metabolic activity is high.

lag phase - The time interval in a bacterial growth curve during which there is no growth.

Here are controversial opinions.

The lag phase is characterized by active metabolism of the cells as they acquire various essential constituents prior to division.

They say bacteria do not proliferate during lag-phase.So, do the bacteria proliferate during lag-phase, at least insignificantly?

 

[Almeisan]

They do not say bacteria do not divide. They say the medium as a whole is not in 'growth stage'.

Bacteria need the right enzymes for maximum metabolism. It takes a while for the cells to notice the changed growth conditions(which are now completely optimal), signal transduction, gene expression, mRNA translation to produce the proteins that actually start growing at the maximum rate.

Lag phase is the phase before exponential growth. Growth in the lag phase can be anywhere from negative to anything just below exponential. When in exponential phase, the bacteria all divide at their minimum interval, meaning their number doubles in this time interval.

Before exponential growth the culture may be in decline, may be growing with a much lower than maximum duplication. The cells usually will be metabolically active, though they don't have to be. If you start out with just endospores, your lag phase will be quite long.All these sources are true. They do not contradict. They just don't use words very carefully. If you want to culture up bacteria, then all growth is exponential growth, or you are in suboptimal conditions and you did something wrong, or are still waiting for lag phase to end.

 

[Eagle9]

Lag phase is the phase before exponential growth

So, during the lag phase bacteria do proliferate (maybe very insignificantly), right?

They just don't use words very carefully

Well, they should, otherwise there will be confusion like this thread