Definition
noun, plural: nif genes
The complex of genes encoding enzymes involved in the fixation of atmospheric nitrogen
Supplement
The nif genes are genes involved in nitrogen fixation. They are found in nitrogen-fixing bacteria. They occur as an operon in free-living anaerobic nitrogen-fixing bacteria such as Klebsiella pneumoniae, Rhodospirillum rubrum, and Rhodobacter capsulatus. These genes may also be found on plasmids (together with the other genes, e.g. nod genes) in symbiotic bacteria, such as in Rhizobium inhabiting the roots of leguminous plants.
The nif genes code for proteins essential in nitrogen fixation, such as nitrogenase and certain regulatory proteins. NifA protein regulated the nif genes transcription. NifA protein is in turn regulated by NtrC. The expression of NifA protein is triggered when fixed nitrogen and oxygen levels are low. In contrast, a sufficient concentration of nitrogen or oxygen would stimulate the protein NifL. The latter inhibits the activity of NifA and this inhibits the formation of nitrogenase.
Nitrogen fixation is important because many living organisms are unable to metabolize directly the atmospheric nitrogen and would require the nitrogen fixation capability of certain bacteria in order to produce a form of nitrogen (e.g. ammonia) that can be readily utilized.
See also:
Dictionary > Nif gene
You will also like...
Freshwater Communities & Lentic Waters
Lentic or still water communities can vary greatly in appearance -- from a small temporary puddle to a large lake. The s..
Sleep and Dreams – Neurology
While learning and intelligence are associated with the functions of a conscious mind, sleep and dreams are activities o..
Meiosis and Alternation of Generations
Plants are characterized by having alternation of generations in their life cycles. This tutorial is a review of plant m..
Muscle
Muscle cells are specialized to generate force and movement. Learn about the different types of muscle tissues in this t..
Developmental Biology
Developmental biology is a biological science that is primarily concerned with how a living thing grows and attains matu..
Freshwater Lentic Communities & Animals
This tutorial looks at some of the communities in freshwater lentic habitats. For instance, symbiosis occurs in a commun..