Expression and content of terminal oxidases in Azotobacter vinelandii grown with excess NH4+ are modulated by O-2 supply
Article
Dmello, R., Purchase, D., Poole, R. and Hill, S. 1997. Expression and content of terminal oxidases in Azotobacter vinelandii grown with excess NH4+ are modulated by O-2 supply. Microbiology. 143 (1), pp. 231-237. https://doi.org/10.1099/00221287-143-1-231
Type | Article |
---|---|
Title | Expression and content of terminal oxidases in Azotobacter vinelandii grown with excess NH4+ are modulated by O-2 supply |
Authors | Dmello, R., Purchase, D., Poole, R. and Hill, S. |
Abstract | The influence of the rate of O2 supply to batch cultures on the contents of cytochromes bd and 'o' in NH4 +-grown Azotobacter vinelandii has been investigated. Difference spectra at room temperature (reduced + CO minus reduced) were recorded for whole cells of a wild-type strain and mutants which either lacked or over-produced the cytochrome bd-type terminal oxidase encoded by cydAB. A Tn5-B20 insertion in cydB in the former mutant also provided a means of monitoring cydAB gene expression from measurements of β-galactosidase activity. The content of cytochrome d in the wild-type, and the expression of cydAB-lacZ, in the mutant, increased as the O2 supply was raised, suggesting that O2 regulates cydAB expression even in the absence of diazotrophy. In a strain carrying a mutation in cydR, a regulatory gene upstream of cydAB, and which over-produces cytochrome bd, the responses to O2 supply during growth at different O2 supply rates were reversed. Changes in the content of a haemoprotein detectable in low temperature photodissociation spectra, and attributed to cytochrome b 595 -the high-spin cytochrome b component of the cytochrome bd complex - followed the changes in cytochrome d levels. CO difference spectra of both the wild-type strain and the cytochrome bd-deficient mutant revealed a haemoprotein with spectral characteristics similar to cytochrome o, the levels of which increased as the O2 supply was raised. These results are discussed with reference to previous reports of cytochrome changes in cells grown under N2-fixing conditions. |
Keywords | Azotobacter vinelandii; cytochrome bd; cytochrome o-like oxidase; O-2 supply and oxidase content; cyd genes |
Sustainable Development Goals | 15 Life on land |
Middlesex University Theme | Sustainability |
Publisher | Microbiology Society |
Journal | Microbiology |
ISSN | 1350-0872 |
Electronic | 1465-2080 |
Publication dates | |
Online | 01 Jan 1997 |
Jan 1997 | |
Publication process dates | |
Accepted | 06 Sep 1996 |
Deposited | 31 Jan 2024 |
Output status | Published |
Digital Object Identifier (DOI) | https://doi.org/10.1099/00221287-143-1-231 |
Scopus EID | 2-s2.0-0031016252 |
Web of Science identifier | WOS:A1997WE41100027 |
Language | English |
https://repository.mdx.ac.uk/item/9706w
31
total views0
total downloads2
views this month0
downloads this month