Abstract
The effects of several organic and inorganic nitrogen compounds on nitrogenase mRNA and enzyme activity levels were examined in anaerobic cultures of Anabaena variabilis 29413. Even low concentrations of exogenous ammonia (20 microM) prevented nitrogenase gene expression. Nitrate, in contrast, had little effect, even at very high concentrations. Neither compound had a significant direct effect on existing enzyme activity. The amino acids glutamine and glutamate did not repress nif gene expression. Methionine sulfoximine, but not 7-azatryptophan, was shown to eliminate the repressive effect of ammonia, and this action occurred at the mRNA level. Low concentrations of carbamyl phosphate caused a rapid decrease in nitrogenase mRNA levels. These results are consistent with the ideas that nif gene regulation in Anabaena spp. occurs primarily at the mRNA level and that ammonia, and possibly also glutamine and glutamate, is not the immediate effector of regulation.
Full text
PDF





Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bottomley P. J., Van Baalen C., Tabita F. R. Heterocyst differentiation and tryptophan metabolism in the chanobacterium Anabaena sp. CA. Arch Biochem Biophys. 1980 Aug;203(1):204–213. doi: 10.1016/0003-9861(80)90170-8. [DOI] [PubMed] [Google Scholar]
- Cannon M., Hill S., Kavanaugh E., Cannon F. A molecular genetic study of nif expression in Klebsiella pneumoniae at the level of transcription, translation and nitrogenase activity. Mol Gen Genet. 1985;198(2):198–206. doi: 10.1007/BF00382996. [DOI] [PubMed] [Google Scholar]
- Collins J. J., Brill W. J. Control of Klebsiella pneumoniae nif mRNA synthesis. J Bacteriol. 1985 Jun;162(3):1186–1190. doi: 10.1128/jb.162.3.1186-1190.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Collins J. J., Roberts G. P., Brill W. J. Posttranscriptional control of Klebsiella pneumoniae nif mRNA stability by the nifL product. J Bacteriol. 1986 Oct;168(1):173–178. doi: 10.1128/jb.168.1.173-178.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gordon J. K., Shah V. K., Brill W. J. Feedback inhibition of nitrogenase. J Bacteriol. 1981 Dec;148(3):884–888. doi: 10.1128/jb.148.3.884-888.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Haselkorn R., Rice D., Curtis S. E., Robinson S. J. Organization and transcription of genes important in Anabaena heterocyst differentiation. Ann Microbiol (Paris) 1983 Jul-Aug;134B(1):181–193. doi: 10.1016/s0769-2609(83)80104-5. [DOI] [PubMed] [Google Scholar]
- Helber J. T., Johnson T. R., Yarbrough L. R., Hirschberg R. Regulation of nitrogenase gene expression in anaerobic cultures of Anabaena variabilis. J Bacteriol. 1988 Feb;170(2):552–557. doi: 10.1128/jb.170.2.552-557.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kanemoto R. H., Ludden P. W. Effect of ammonia, darkness, and phenazine methosulfate on whole-cell nitrogenase activity and Fe protein modification in Rhodospirillum rubrum. J Bacteriol. 1984 May;158(2):713–720. doi: 10.1128/jb.158.2.713-720.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lawrie A. C. Effect of carbamoyl phosphate on nitrogenase in Anabaena cylindrica Lemm. J Bacteriol. 1979 Jul;139(1):115–119. doi: 10.1128/jb.139.1.115-119.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meeks J. C., Wolk C. P., Lockau W., Schilling N., Shaffer P. W., Chien W. S. Pathways of assimilation of [13N]N2 and 13NH4+ by cyanobacteria with and without heterocysts. J Bacteriol. 1978 Apr;134(1):125–130. doi: 10.1128/jb.134.1.125-130.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Peterson R. B., Wolk C. P. High recovery of nitrogenase activity and of Fe-labeled nitrogenase in heterocysts isolated from Anabaena variabilis. Proc Natl Acad Sci U S A. 1978 Dec;75(12):6271–6275. doi: 10.1073/pnas.75.12.6271. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rice D., Mazur B. J., Haselkorn R. Isolation and physical mapping of nitrogen fixation genes from the cyanobacterium Anabaena 7120. J Biol Chem. 1982 Nov 10;257(21):13157–13163. [PubMed] [Google Scholar]
- Rogerson A. C. Modifiers of heterocyst repression and spacing and formation of heterocysts without nitrogenase in the cyanobacterium Anabaena variabilis. J Bacteriol. 1979 Oct;140(1):213–219. doi: 10.1128/jb.140.1.213-219.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stacey G., Bottomley P. J., Van Baalen C., Tabita F. R. Control of heterocyst and nitrogenase synthesis in cyanobacteria. J Bacteriol. 1979 Jan;137(1):321–326. doi: 10.1128/jb.137.1.321-326.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stewart W. D. Some aspects of structure and function in N2-fixing cyanobacteria. Annu Rev Microbiol. 1980;34:497–536. doi: 10.1146/annurev.mi.34.100180.002433. [DOI] [PubMed] [Google Scholar]
- Thiel T., Leone M. Effect of glutamine on growth and heterocyst differentiation in the cyanobacterium Anabaena variabilis. J Bacteriol. 1986 Nov;168(2):769–774. doi: 10.1128/jb.168.2.769-774.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]