1887

Abstract

Summary: Cyanobacteria assigned to the genus are an important component of oligotrophic marine ecosystems, where their growth may be constrained by low availability of fixed nitrogen. Urea appears to be a major nitrogen resource in the sea, but little molecular information exists about its utilization by marine organisms, including Oligonucleotide primers were used to amplify a conserved fragment of the urease (urea amidohydrolase, EC 3.5.1.5) coding region from cyanobacteria. A 5·7 kbp region of the genome of the unicellular marine cyanobacterium sp. strain WH7805 was then cloned, and genes encoding three urease structural subunits and four urease accessory proteins were sequenced and identified by homology. The WH7805 urease had a predicted subunit composition typical of bacterial ureases, but the organization of the WH7805 urease genes was unique. Biochemical characteristics of the WH7805 urease enzyme were consistent with the predictions of the sequence data. Physiological data and sequence analysis both suggested that the urease operon may be nitrogen-regulated by the system in WH7805. Inactivation of the large subunit of urease, prevented WH7805 and WH8102 from growing on urea, demonstrating that the urease genes cloned are essential to the ability of these cyanobacteria to utilize urea as a nitrogen source.

Loading

Article metrics loading...

/content/journal/micro/10.1099/13500872-145-2-447
1999-02-01
2019-11-15
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/13500872-145-2-447
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error