Number of species in the collection: 7.

 

 

Phyla:                                               

 

Gammaproteobacteria (Gama-proteobacteria) 

 

Pictures of Proteobacteria:                           

 

 

Characteristics of Proteobacteria:                 

 

The kingdom of Proteobacteria (named after the Greek god Proteus, capable of assuming any form) constitutes the most diverse kingdom of life, possessing extraordinarily varied metabolisms. It contains species that do not respire oxygen (are anaerobic), or that can respire oxygen, nitrates, sulfates, iron... feed on organic matter, mineral matter, perform photosynthesis releasing sulfur or sulfate instead of oxygen, can use hydrogen as a source of electrons for photosynthesis, are capable of transforming nitrogen from the air into organic nitrogen, or can feed on carcinogenic compounds or extremely lethal compounds to other organisms. Due to this high variability, the group is defined by the similarities of its DNA.

This kingdom includes most of the bacteria that live inside other organisms. For example, our intestine has a large number of species, which can weigh in total almost 2 kg. In fact, our bodies have more cells of proteobacteria than human cells (since bacterial cells are much smaller than human cells and do not take up as much space). Furthermore, within this kingdom are most pathogenic bacteria, causing many diseases.

One of the many metabolisms that the group possesses, which allows the use of oxygen to release energy from food, is the metabolism that all Eukaryota (which contains animals, plants, or fungi among other kingdoms) possess. Eukaryota acquired this essential ability through an ancestral event of intracellular symbiosis with a proteobacterium. Over millions of years, this proteobacterium degenerated into a cellular organelle, the mitochondrion, which is responsible for obtaining energy from nutrients.
 

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