Lactobacillus plantarum WCFS1 requires both heme and menaquinone to induce respiration-like behavior under aerobic conditions. The addition of these compounds enhanced both biomass production, without progressive acidification, and the oxygen consumption rate. When both heme and menaquinone were present, L. plantarum WCFS1 was also able to reduce nitrate. The ability to reduce nitrate was sever...

Introduction Nitrogen fixation by legumes is the product of a symbiosis of legume plants and a group of bacteria known as rhizobia (Carroll, et al., 1985; Kinkema, et al., 2006). It has been hypothesised that when rhizobia receive flavonoid signals from the host plants, production of a chemical nodulation factor is induced. The perception of nodulation factor by legume roots then activates a si...

We examined molybdenum cofactor activity in chlorate-resistant (chl) and nitrate reductase-deficient (nar) insertion mutants and wild-type strains of Escherichia coli K-12. The bacterial molybdenum cofactor was assayed by its ability to restore activity to the cofactor-deficient nitrate reductase found in the nit-1 strain of Neurospora crassa. In the wild-type E. coli strains, molybdenum cofact...

Here, we investigate the functionality of the oxygen-responsive nitrogen regulation system NreABC in the human pathogen Staphylococcus aureus and evaluate its role in anaerobic gene regulation and virulence factor expression. Deletion of nreABC resulted in severe impairment of dissimilatory nitrate and nitrite reduction and led to a small-colony phenotype in the presence of nitrate during anaer...

The narKGHJI operon that comprises putative nitrate/nitrite transporter (narK) and nitrate reductase (narGHJI) genes is required for the anaerobic growth of Corynebacterium glutamicum with nitrate as a terminal electron acceptor. In this study, we identified a gene, arnR, which encodes a transcriptional regulator that represses the expression of the narKGHJI operon in C. glutamicum cells under ...

Two transmembrane proteins were tentatively classified as NarK1 and NarK2 in the Pseudomonas genome project and hypothesized to play an important physiological role in nitrate/nitrite transport in Pseudomonas aeruginosa. The narK1 and narK2 genes are located in a cluster along with the structural genes for the nitrate reductase complex. Our studies indicate that the transcription of all these g...

Brucella is the causative agent of the zoonotic disease brucellosis, which is endemic in many parts of the world. Genome sequencing of B. suis and B. melitensis revealed that both are complete denitrifiers. To learn more about the role of denitrification in these animal pathogens, a study of the role of denitrification in the closely related B. neotomae was undertaken. In contrast to B. suis an...

The opportunistic pathogen Burkholderia pseudomallei is a saprophytic bacterium and the causative agent of melioidosis, an emerging infectious disease associated with high morbidity and mortality. Although melioidosis is most prevalent during the rainy season in endemic areas, domestic gardens and farms can also serve as a reservoir for B. pseudomallei during the dry season, in part due to irri...