RESUMO
Global nitrogen cycling is mainly mediated by the activity of microorganisms. Nitrogen cycle processes are mediated by functional groups of microorganisms that are affected by constantly changing environmental conditions and substrate availability. In this study, we investigated the temporal and spatial patterns of nitrifier and denitrifier communities in an intertidal wetland. Soil samples were collected over four distinct seasons from three locations with different vegetative cover. Multiple environmental factors and process rates were measured and analyzed together with the community size and composition profiles. We observed that the community size and composition of the nitrifiers and denitrifiers are affected significantly by seasonal factors, while vegetative cover affected the community composition. The seasonal impacts on the community size of ammonia oxidizing archaea (AOA) are much higher than that of ammonia oxidizing bacteria (AOB). The seasonal change was a more important indicator for AOA community composition patterns, while vegetation was more important for the AOB community patterns. The microbial process rates were correlated with both the community size and composition.
RESUMO
Tidal flats are soil resources of great significance. Nitrification plays a central role in the nitrogen cycle and is often a critical first step in nitrogen removal from estuarine and coastal environments. We determined the abundance as well as composition of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in different soils during land reclamation process. The abundance of AOA was higher than that of AOB in farm land and wild land while AOA was not detected in tidal flats using real-time polymerase chain reaction (PCR). The different abundances of AOB and AOA were negatively correlated with the salinity. The diversities of AOB and AOA were also investigated using clone libraries by amplification of amoA gene. Among AOB, nearly all sequences belonged to the Nitrosomonas lineage in the initial land reclamation process, i.e., tidal flats, while both Nitrosomonas and Nitrosospira lineages were detected in later and transition phases of land reclamation process, farm land and wild land. The ratio of the numbers of sequences of Nitrosomonas and Nitrosospira lineages was positively correlated with the salinity and the net nitrification rate. As for AOA, there was no obvious correlation with the changes in the physicochemical properties of the soil. This study suggests that AOB may be more import than AOA with respect to influencing the different land reclamation process stages.
Assuntos
Amônia/metabolismo , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/isolamento & purificação , Bactérias/metabolismo , Microbiologia do Solo , Archaea/classificação , Archaea/genética , Proteínas Arqueais/genética , Bactérias/classificação , Bactérias/genética , Proteínas de Bactérias/genética , Biodiversidade , China , Conservação dos Recursos Naturais , DNA Arqueal/genética , DNA Arqueal/isolamento & purificação , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Estuários , Genes Arqueais , Genes Bacterianos , Dados de Sequência Molecular , Nitrificação , Ciclo do Nitrogênio , Oxirredução , Oxirredutases/genética , Filogenia , Rios/microbiologiaRESUMO
Two Gram-negative, rod-shaped, motile, aerobic bacterial strains designated HY-14(T) and HY-24 were isolated from the sludge of an anaerobic ammonium-oxidizing bioreactor. The strains could not grow with 5 % (w/v) NaCl, did not produce acid from d-glucose or utilize d-glucose, gluconate or citrate as a sole carbon source. Summed feature 3 and C(16 : 0) were the most abundant fatty acids; hydroxyl fatty acids C(12 : 0) 3-OH and C(10 : 0) 3-OH were also present. Fatty acid C(12 : 0) 2-OH was absent. The DNA G+C contents of strains HY-14(T) and HY-24 were 50.6+/-0.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains HY-14(T) and HY-24 formed a monophyletic clade within the genus Pseudomonas. The highest sequence similarities were to Pseudomonas pseudoalcaligenes DSM 50188(T) (95.9 %). On the basis of phenotypic and phylogenetic properties, strains HY-14(T) and HY-24 are proposed as a novel species of the genus Pseudomonas, for which the name Pseudomonas caeni sp. nov. is proposed. The type strain is HY-14(T) (=KCTC 22292(T)=CCTCC AB208156(T)).
Assuntos
Reatores Biológicos/microbiologia , Nitritos/metabolismo , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo , Compostos de Amônio Quaternário/metabolismo , Esgotos/microbiologia , Anaerobiose , DNA Bacteriano/genética , DNA Ribossômico/genética , Dados de Sequência Molecular , Oxirredução , Filogenia , Pseudomonas/classificação , Pseudomonas/genética , RNA Ribossômico 16S/genéticaRESUMO
An anaerobic ammonium-oxidation (anammox) reactor was operated for more than 500 days and the anammox activity of the biomass in the reactor reached 0.58 kg N(total)/kg VSS d. The removal ratios of NO2(-)-N to NH4(+)-N in both reactor and activity tests were nearly 1.1. The bacterial diversity in the reactor was investigated by analysis of 16S rRNA gene clone libraries and quantitative real-time PCR (qPCR). The analysis showed that more than half of the clones in the library were affiliated to recognized filamentous bacteria. The previously recognized anammox bacterium (AnAOB) Candidatus Kuenenia stuttgartiensis was only detected by using a Planctomycetes-specific 16S rRNA gene primer set. However, at least two different types of AnAOB were detected by the primer set targeting the hydrazine-oxidizing enzyme gene (hzo). The aerobic ammonium-oxidizing bacteria (AAOB) Nitrosomonas europaea-eutropha group, which is widely detected in oxygen-limited environments, was also found in this reactor. The result of qPCR indicated that AnAOB comprised 16% of the community population while AAOB comprised less than 1% in the reactor.
