title: Detection of the isiA gene across cyanobacterial strains: potential for probing iron deficiency.
abstract: The use of isiA expression to monitor the iron status of cyanobacteria was investigated. Studies of laboratory cultures of the cyanobacterium Synechocystis sp. strain PCC 6803 showed that isiA expression is dependent on the organism's response to iron deficiency; isiA expression starts as soon as a decline in the rate of growth begins. isiA expression is switched on at concentrations of iron citrate of less than 0.7 microM. A PCR method was developed for the specific amplification of the iron-regulated isiA gene from a variety of cyanobacteria. After we developed degenerate primers, 15 new internal isiA fragments (840 bp) were amplified, cloned, and sequenced from strains obtained from algal collections, from new isolates, and from enriched field samples. Furthermore, isiA expression could be detected by means of reverse transcription-PCR when enriched field samples were exposed to restricted iron availability. These results imply that determining the level of iron-regulated isiA expression can serve to indicate iron deficiency in cyanobacterial samples of differing origins from the field.
authors.affiliation: Institut für Okologie, Botanisches Institut, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Geiss
authors.forename: J
authors.initials: J
authors.lastname: Vinnemeier
authors.forename: A
authors.initials: A
authors.lastname: Kunert
authors.forename: I
authors.initials: I
authors.lastname: Lindner
authors.forename: B
authors.initials: B
authors.lastname: Gemmer
authors.forename: M
authors.initials: M
authors.lastname: Lorenz
authors.forename: M
authors.initials: M
authors.lastname: Hagemann
authors.forename: A
authors.initials: A
authors.lastname: Schoor
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D000458:Cyanobacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C083100:photosystem II, chlorophyll binding protein, CP-43; C076726:chlorophyll A binding protein CP43, Cyanobacteria; D007501:Iron