Effects of Co-existing Heterotrophs on Physiology of and Nitrogen Metabolism in Autotrophic Nitrite-oxidizing Candidatus Nitrotoga.

Interactions between autotrophic nitrifiers and heterotrophs have attracted considerable attention in microbial ecology. However, the mechanisms by which heterotrophs affect the physiological activity of and nitrogen metabolism in autotrophic nitrite oxidizers remain unclear. We herein focused on nitrite-oxidizing Candidatus Nitrotoga and compared an axenic culture including only Ca. Nitrotoga with a co-culture of both Ca. Nitrotoga and Acidovorax in physiological experiments and transcriptomics. In the co-culture with Acidovorax, nitrite consumption by Ca. Nitrotoga was promoted, and some genes relevant to nitrogen metabolism in Ca. Nitrotoga were highly expressed. These results provide insights into the mechanisms by which co-existing heterotrophs affect autotrophic nitrifiers.

Draft Genome Sequence of Acidovorax sp. Strain NB1, Isolated from a Nitrite-Oxidizing Enrichment Culture.

Here, we report the draft genome sequence of Acidovorax sp. strain NB1, isolated from an enrichment culture of nitrite-oxidizing bacteria (NOB). Genes involved in denitrification were found in the draft genome of NB1. The closest strain to NB1 based on genomic relatedness is Acidovorax sp. strain GW101-3H11, with 91.5% average nucleotide identity.