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PROVIDER: PRJNA1220384 | ENA |
REPOSITORIES: ENA
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Project description:Drinking Water Distribution System Bacteria targeted loci 16S
| PRJNA287069 | ENA
Project description:Quorum sensing (QS) is a widespread process in bacteria used to coordinate gene expression with cell density, diffusion dynamics, and spatial distribution through the production of diffusible chemical signals. To date, most studies on QS have focused on model bacteria that are amenable to genetic manipulation and capable of high growth rates, but many environmentally important bacteria have been overlooked. For example, representatives of proteobacteria that participate in nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, produce QS signals called acyl-homoserine lactones (AHLs). Nitrification emits nitrogen oxide gases (NO, NO2, and N2O), which are potentially hazardous compounds that contribute to global warming. Despite considerable interest in nitrification, the purpose of QS in the physiology/ecology of nitrifying bacteria is poorly understood. Through a quorum quenching approach, we investigated the role of QS in a well-studied AHL-producing nitrite oxidizer, Nitrobacter winogradskyi.We added a recombinant AiiA lactonase to N. winogradskyi cultures to degrade AHLs to prevent their accumulation and to induce a QS-negative phenotype and then used mRNA sequencing (mRNA-Seq) to identify putative QS-controlled genes. Our transcriptome analysis showed that expression of nirK and nirK cluster genes (ncgABC) increased up to 19.9-fold under QS-proficient conditions (minus active lactonase). These data led to us to query if QS influenced nitrogen oxide gas fluxes in N. winogradskyi. Production and consumption of NOx increased and production of N2O decreased under QS-proficient conditions. Quorum quenching transcriptome approaches have broad potential to identify QS-controlled genes and phenotypes in organisms that are not genetically tractable.
2016-10-05 | GSE84969 | GEO
Project description:Salinity strongly influences the physiology and distribution of nitrifying microorganisms, yet the effects of low salinity on these key players in nitrogen cycling remain understudied. This study investigates the impact of hypoosmolarity on different groups of ammonia oxidizers in soil and lake environments, as well as in pure culture isolates. In soil microcosms amended with ammonium, at low salinity levels (~120 µS/cm), which are comparable to values commonly found in pristine terrestrial and aquatic environments, the abundance of ammonia-oxidizing bacteria (AOB), dominated by Nitrosomonas oligotropha, significantly increased. In contrast, the growth of ammonia-oxidizing archaea (AOA), dominated by “Ca. Nitrosotenuis” of the Nitrosopumilaceae family, was stimulated by high salinity (~760 µS/cm). In ammonium-fed lake microcosms, the abundance of AOB, dominated by N. oligotropha, significantly increased under both low (~170 µS/cm) and high salinity (~850 µS/cm) conditions. In the presence of allylthiourea, a bacterial nitrification inhibitor, AOA were found to be sensitive to low salinity in both soil and lake microcosms. Consistently, pure culture studies revealed marked growth inhibition of AOA, especially of members of the Nitrosopumilaceae, under hypoosmolarity, unlike AOB and complete ammonia oxidizers (comammox) strains. Comparative genomic analyses with AOB and comammox, along with transcriptomic studies, suggested that the sensitivity of AOA to hypoosmolarity stress is attributed to a lack of sophisticated osmoregulatory transport systems and their S-layer cell wall structure. Overall, this study highlights the importance of hypoosmolarity as a key factor shaping the ecological niches and distribution of ammonia oxidizers as well as nitrification activities in terrestrial and aquatic environments increasingly affected in their salinities by intensified water cycles due to climate change.
2026-04-06 | PXD064500 | Pride