Induction of siderophore activity in Anabaena spp. and its moderation of copper toxicity

Journal Article · Fri May 01 04:00:00 EDT 1987 · Appl. Environ. Microbiol.; (United States)

OSTI ID:6496899

Clarke, S E; Stuart, J; Sanders-Loehr, J

Growth of Anabaena sp. strain 7120 (in the absence of chelators or added iron) was inhibited by the addition of 2.1 to 6.5 ..mu..M copper and was abolished by copper concentrations of 10 /sup +/M or higher. When the copper was chelated to schizokinen, the toxic effects were eliminated. Analysis of culture filtrates showed that the cupric schizokinen remains in the medium, thereby lowering the amount of copper taken up by the cells. Although this organism actively transports ferric schizokinen, it apparently does not recognize the cupric complex. Thus, Anabaena sp. is protected from copper toxicity under conditions in which siderophore is being produced. For cells grown in low iron, the accumulation of extracellular schizokinen was observed to parallel cell growth and continue well into stationary phase. The actual iron status of the organism was monitored by using iron uptake velocity as an assay. Cultures grown on 0.1 ..mu..M added iron were found to be severely iron limited upon reaching stationary phase, thus explaining the continued production of schizokinen. These data show that the siderophore system in Anabaena spp. has developed primarily as a response to iron starvation and that additional functions such as alleviation of copper toxicity or allelopathic inhibition of other algal species are merely secondary benefits.

• Research Organization: Portland State Univ., Oregon
• OSTI ID: 6496899
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 53:5; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
COPPER
CYANOBACTERIA
ELEMENTS
IRON
METALS
MICROORGANISMS
RESPONSE MODIFYING FACTORS
SENSITIVITY
TOXICITY
TRANSITION ELEMENTS
UPTAKE