Dichotomous Keys and Characteristics of Gram-Negative Bacteria and Related Groups

What are the five classes of Pseudomonadota?

Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Campylobacterota.

What is a characteristic of Alphaproteobacteria?

Most can grow with very low levels of nutrients and many have stalks or buds known as prosthecae.

What role does Pelagibacter play in the environment?

It is one of the most abundant microorganisms in oceans and plays an important role in Earth's carbon cycle.

What is the function of Azospirillum?

It grows in soil using nutrients excreted by plants and forms associations with roots, fixing nitrogen.

What do Acetobacteraceae convert?

ethanol into acetic acid.

What diseases are caused by Rickettsia?

R. prowazekii causes epidemic typhus, R. typhi causes endemic murine typhus, and R. rickettsii causes Rocky Mountain spotted fever.

What does Ehrlichia cause and how is it transmitted?

ehrlichiosis and is transmitted by ticks.

What is the significance of Rhizobium and Bradyrhizobium?

They fix nitrogen in the roots of leguminous plants

What is the role of Agrobacterium in plants?

a plant pathogen that causes crown gall by inserting a plasmid into plant cells, inducing a tumor.

What does Brucella cause?

brucellosis and is an obligate parasite of mammals.

What is the function of Wolbachia?

It is an endosymbiont of insects that affects their reproduction and may be used for insect control.

What diseases are associated with the genus Vibrio?

Vibrio cholerae causes cholera, and Vibrio parahaemolyticus causes gastroenteritis.

What is the significance of Escherichia coli?

an indicator of fecal contamination, with some strains causing foodborne disease and urinary tract infections.

What does Salmonella cause?

foodborne illness, with Salmonella Typhi causing typhoid fever.

What is the role of Bdellovibrio?

attacks other gram-negative bacteria.

What is unique about the life cycle of Chlamydia?

has an elementary body that is infective.

What are the key features of spirochetes?

They are coiled and move via axial filaments, creating a corkscrew type of motility.

What does Treponema pallidum cause?

It causes syphilis.

What is the significance of Streptomyces in medicine?

known for producing many antibiotics.

What is the G+C content range for Mycobacterium?

between 62-70%.

What does Listeria monocytogenes contaminate?

food and can cause serious infections.

What is the role of Cytophaga in the environment?

Cytophaga degrades cellulose and chitin in soil.

What are extremophiles?

organisms that proliferate under extreme environmental conditions.

What limits our knowledge of microbial diversity?

the vastness of microbial habitats and the difficulty in culturing many microorganisms.