Distinct Expression of the Two NO-Forming Nitrite Reductases in Thermus antranikianii DSM 12462T Improved Environmental Adaptability.

Distinct Expression of the Two NO-Forming Nitrite Reductases in Thermus antranikianii DSM 12462T Improved Environmental Adaptability. Microb Ecol. 2020 May 30;: Authors: Liu RR, Tian Y, Zhou EM, Xiong MJ, Xiao M, Li WJ Abstract Hot spring ecosystems are analogous to some thermal environments on the early Earth and represent ideal models to understand life forms and element cycling on the early Earth. Denitrification, an important component of biogeochemical nitrogen cycle, is highly active in hot springs. Nitrite (NO2-) reduction to nitric oxide (NO) is the significant and rate-limiting pathway in denitrification and is catalyzed by two types of nitrite reductases, encoded by nirS and nirK genes. NirS and NirK were originally considered incompatible in most denitrifying organisms, although a few strains have been reported to possess both genes. Herein, we report the functional division of nirS and nirK in Thermus, a thermophilic genus widespread in thermal ecosystems. Transcriptional levels of nirS and nirK coexisting in Thermus antranikianii DSM 12462T were measured to assess the effects of nitrite, oxygen, and stimulation time. Thirty-nine Thermus strains were used to analyze the phylogeny and distribution of nirS and nirK; six representative strains were used to assess the denitrification phenotype. The results showed that both genes were actively transcribed and expressed independently in T. antranikianii DSM 12462T. Strains with...
Source: Microbial Ecology - Category: Microbiology Authors: Tags: Microb Ecol Source Type: research