Siderophores
Siderophores are lower molecular weight (500 - 1500 Dalton) iron chelating substance produced by certain groups of plant, fungi and bacteria. The Bacillus most commonly produce the sidrophore at neutral pH. At the neutral pH the organism cannot uptake the Fe2+ ions because in presence of oxygen and in neutral pH Fe2+ is converted into Fe3+.
Types of Siderophore produced by various Bacillus species:
B. subtilis produces Hexadentate Bacillibactin.
B. anthracis and B. cereus produces both Bacillibactin and Petrobactin.
Mechanism of Siderophore during iron deficient condition.
Initially siderophore are produced during neutral pH which has affinity to Fe3+ , resulting in formation of Iron-Siderophore complex. This complex is transported into the cytoplasm via siderophore permease receptor. Once inside the sidrophore emits the Fe3+ of its binding site and siderophore is sent back to circulation and Fe3+ is converted into Fe2+ in presence of Ferric reductase. The Fe2+ plays important role in various metabolic process.
COMPETITION:
Each bacteria has its own siderophore which has its own receptor for iron uptake.
In an environment consortium of organisms are present which compete for iron source using there siderophore.
The competition of the strains depends on various factors such as amount of siderophore produced, iron binding properties and dynamics of siderophore production.
APPLICATION:
Enhance the growth of plant by supplying iron and biocontrol of pathogen.
Disease control in fishes by limiting the amount of iron required for virulence bacteria.
Bioremediation for environmental pollution.
Drug delivery mechanism in disease caused by gram negative bacteria.
Anti-cancer drug by limiting the amount of iron required for the development of cancer cells.