What does prototroph mean?
A prototroph is a microorganism or strain that can make the nutrients it needs rather than depending on one or more nutrients supplied by its surroundings. In microbial genetics, the term is especially important when describing organisms that can grow on a minimal medium. A prototrophic strain may synthesize amino acids, vitamins, and other growth factors that an auxotrophic strain cannot produce. In broader ecological usage, a prototroph is an organism that obtains its food from inorganic substances, as autotrophic organisms generally do. The word combines elements meaning “first” and “nourished” or “feeding,” reflecting its historical association with nourishment from a primary source. Although usually applied to microorganisms, the term is technical and is encountered mainly in microbiology, genetics, and discussions of nutritional mutations. Its counterpart, auxotroph, is often used in the same experimental contexts to identify strains with specific nutritional requirements.
nounA prototroph is a microorganism or strain that can synthesize the nutrients it needs and therefore grow on a minimal medium without supplied growth factors. More broadly, the term denotes an organism that obtains nourishment from inorganic substances rather than from organic food.
- A microorganism or strain able to synthesize all the nutrients required for growth, allowing it to grow on a minimal medium without added growth factors.
- An organism that obtains its nourishment from inorganic substances, especially through photosynthesis or chemosynthesis.
"After several generations of selection, the researchers identified a prototroph capable of growing without added amino acids."
"The prototroph grew on a minimal agar medium containing only inorganic salts and a carbon source."
"Prototrophic organisms can use light and inorganic compounds to produce the organic substances needed for life."
The regular plural is used when referring to individual microorganisms, strains, or organisms of this kind.
"Several prototrophs were isolated from the enriched culture."
A prototroph is a biological self-supporter; its opposite, an auxotroph, cannot grow without nutritional help.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does prototroph come from?
The word comes from Greek prōtotrophos, formed from prōto-, meaning “first” or “original,” and trophos, meaning “nourished” or “feeding.” It was adopted into biology for organisms able to obtain or synthesize their nourishment independently. Its best-known scientific relatives are autotroph, heterotroph, phototroph, and chemotroph, all of which combine forms of the Greek root trophos with terms describing their source of nutrition or energy.
Related word forms
How prototroph is actually used
The term is chiefly used in microbiology and microbial genetics, especially in studies of mutations, nutritional requirements, and reversion. In genetics, it normally describes a strain capable of growing without a particular supplement; in broader biological usage, it can describe an organism that nourishes itself from inorganic sources.
Easily confused with prototroph
A prototroph can synthesize the nutrients it needs, whereas an auxotroph requires one or more supplied nutrients or growth factors.
A prototroph can produce its own organic nutrients, while a heterotroph obtains organic material from other organisms or organic matter.