This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Kaplan, D. Articles by Peters, G. A. Search for Related Content PubMed PubMed Citation Articles by Kaplan, D. Articles by Peters, G. A. Agricola Articles by Kaplan, D. Articles by Peters, G. A.

Articles

The Azolla-Anabaena azollae Relationship ¹

XII. Nitrogenase Activity and Phycobiliproteins of the Endophyte as a Function of Leaf Age and Cell Type

Battelle-C. F. Kettering Research Laboratory, P. O. Box 268, Yellow Springs, Ohio 45387

Nitrogenase activity was measured in leaves along the main stem axes of Azolla pinnata R. Br. The activity was negligible in leaves of the apical region, rapidly increased to a maximum as leaves matured, and declined in aging leaves. In situ absorption and fluorescence emission spectra were obtained for individual vegetative cells and heterocysts in filaments of the A. pinnata and Azolla caroliniana endophytes removed from the cavities of progressively older leaves. These spectra unequivocally demonstrate the occurrence of phycobiliproteins in the two cell types of both endophytes at the onset of heterocyst differentiation in filaments from young leaves, during the period of maximal nitrogenase activity in filaments from mature leaves, and in filaments from leaves entering senescence. Phycobiliproteins of the A. caroliniana endophyte were purified and extinction coefficients determined for the phycoerythrocyanin, phycocyanin, and allophycocyanin. The phycobiliprotein content and complement of sequential leaf segments from main stem axes and of vegetative cell and heterocyst preparations were measured in crude extracts. There was no obvious alteration of the phycobiliprotein complement associated with increasing heterocyst frequency of the endophyte in sequential leaf segments and the phycobiliprotein complement of heterocysts was not appreciably different from that of vegetative cells. These findings indicate that the phycobiliprotein complement of the vegetative cell precursor is retained in the heterocysts of the endophyte.

¹ Supported in part by United States Department of Agriculture-Competitive Research Grants Office Grants 79-59-2394-1-1-330-1 and 83-CRCR-1-1296. Contribution No. 878 from the Battelle-C.F. Kettering Research Laboratory.

This article has been cited by other articles:

				K. Baier, H. Lehmann, D. P. Stephan, and W. Lockau NblA is essential for phycobilisome degradation in Anabaena sp. strain PCC 7120 but not for development of functional heterocysts Microbiology, August 1, 2004; 150(8): 2739 - 2749. [Abstract] [Full Text] [PDF]

				J. A. G. O. de Alda, C. Lichtle, J.-C. Thomas, and J. Houmard Immunolocalization of NblA, a protein involved in phycobilisome turnover, during heterocyst differentiation in cyanobacteria Microbiology, May 1, 2004; 150(5): 1377 - 1384. [Abstract] [Full Text] [PDF]

				J. C. Meeks and J. Elhai Regulation of Cellular Differentiation in Filamentous Cyanobacteria in Free-Living and Plant-Associated Symbiotic Growth States Microbiol. Mol. Biol. Rev., March 1, 2002; 66(1): 94 - 121. [Abstract] [Full Text] [PDF]