Bacteria Uptaking DNA Filmed for the First Time

Bacteria uptaking DNA from their environment using tube like appendages is captured on camera for the first time. Bacteria usually transfer DNA between themselves to spread antibiotic or drug resistance and disease forming (virulence) factors.  For example, if a bacterium has a DNA that helps it to survive in the presence of antibiotic like penicillin, it can act as a donor of the penicillin resistance DNA. It can donate that DNA to another bacterium which lacks that DNA. 

(Image of E. coli bacteria from Wikipedia)

They can transfer such DNAs in three different methods. First method is taking up DNA from their environment. This is the method they have captured on camera using fluorescence microscope for the first time. In the second method, two bacteria transfer DNA by direct contact. One bacterium forms a tube-like appendage called pilus (plural: pili) and attach the pilus to another bacterium. The DNA from the donor bacterium transfer through the pilus to the recipient bacterium. This method is scientifically known as bacterial conjugation. 

In the third method, the DNA transfers through tiny bacterial virus called bacteriophage. The bacteriophages infect and multiply inside the bacteria. After multiplication, the viruses destroy the bacteria and release out to the environment. They may carry some of the bacterial DNA and transfer them to another bacteria. This is part of the life cycle of the bacteriophages. This method of transferring DNA is known as bacterial transduction. 

(Animation of a bacteria up taking DNA)

In the current published work, the scientists used fluorescence dyes to show DNA in red colour and Vibrio choleraebacteria in green colour.  They observed the live bacteria under the fluorescence microscope which helps to see fluorescence dyed objects. They noticed that the bacteria extended pili to nearby DNA and attached to the DNA. Then, the bacteria take the DNA inside their membrane. This live cell observation has proved that the bacteria can uptake DNA from their environment. This phenomenon helps bacteria to acquire drug or antibiotic resistance and virulence factors. 

In any environment, like our intestines and soil, there are several types of bacterial species live together. In order to survive and thrive in such a competitive environment, the bacteria need to be strong and fit. Hence, they uptake or receive DNA that makes them strong from the environment and from other bacteria.