Bacterial cells are extremely efficient machineries able to survive and proliferate even in the harshest environments.

Even if we do not see them, because they are microscopic organisms, we can find bacteria all over the place. Our skin and body carry a considerable number of bacteria (usually harmless and many of them beneficial). Some bacteria contribute to make our meals more palatable (cheese, yogurt...). But sometimes they can spoil our food or bring disease to our lives causing infections.

Bacteria posses very refined and precise mechanisms to control the time when they divide and the site where they place a structure, called septum, that physically separates one daughter cell from its sister.

Despite, or more likely because of, their constrained dimensions, bacteria are very successful life forms, different species being able to colonise the most extreme and diverse environments. The comparative simplicity of bacterial cells is reflected in their genomic sizes: a free-living Mycoplasma may cope with life with just 1% the number of genes that a human cell needs to carry. As bacterial genes generally lack introns, the economy in genetic material is even more remarkable: one human cell contains more DNA than 1000 Escherichia coli cells. Microbes nevertheless manage their limited amount of genetic information in an exquisite manner, exploiting all imaginable devices at the molecular, physiological and cellular levels to survive and proliferate.