Proteobacteria

Definition

Proteobacteria are a major phylum of Gram-negative bacteria that includes a wide variety of pathogenic and non-pathogenic species. They are characterized by their diverse metabolic capabilities and roles in various environments.

5 Must Know Facts For Your Next Test

1. Proteobacteria are classified into six classes: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, and Zetaproteobacteria.
2. Many Proteobacteria are capable of nitrogen fixation, which is crucial for converting atmospheric nitrogen into a form usable by plants.
3. Proteobacteria include notable pathogens such as Escherichia coli, Salmonella, and Helicobacter pylori.
4. They exhibit a wide range of metabolic diversity including phototrophy, lithotrophy, and heterotrophy.
5. Proteobacteria play vital roles in the human microbiome, particularly in the gut and respiratory tract.

Review Questions

• What are the six classes of Proteobacteria?
• Name three pathogenic species that belong to the Proteobacteria phylum.
• How do Proteobacteria contribute to nitrogen fixation?

Related terms

Gram-Negative Bacteria: Bacteria that have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides.

Nitrogen Fixation:

The process through which atmospheric nitrogen is converted into ammonia or related molecules available to living organisms.

Microbiome:

The collection of all microorganisms living in association with the human body or another environment.