| Congresso Brasileiro de Microbiologia 2023 | Resumo: 967-2 | ||||
Resumo:Nitrification is an important step in the marine nitrogen cycle, accounting for up to 36% of bioavailable nitrogen. Ammonia-oxidizing archaea (AOA) from the class Nitrososphaeria are widely distribution and play a key role in marine nitrogen cycling by performing the first step of nitrification while fixing inorganic carbon. Most Nitrososphaeria species are uncultivated, with only a few isolated. Recent studies have indicated the importance of these organisms to the marine environment, but our knowledge is still very limited, with scarce information available about the diversity and ecology of these microorganisms in the Southwest Atlantic Ocean. This study used samples collected from the Cananeia estuary for AOA cultivation, with the support from Institute Oceanographic of the University of Sao Paulo (IO-USP) and Graduate Research Base “Dr. João de Paiva Carvalho”. The culture obtained was highly enriched in ammonia-oxidizing archaea from the family Nitrosopumilaceae (63%), as well as ammonia-oxidizing bacteria from the family Nitrosomonadaceae (4%). Nitrite-oxidizing bacteria of the genus Nitrospira was also present in the culture, accounting for 2% of the community. Treatments that included antibiotics and incubation at 20ºC tended to favour AOA enrichment. Along with the growth curve, the consumption of ammonium occurred concomitantly with the increase in the concentration of nitrate. The metagenome analysis enable the recovery of an archaeal genome classified as Nitrosarchaeum genus, family Nitrosopumilaceae. This genome showed genes related to nitrogen and carbon metabolism, as well as cofactors and vitamins biosynthesis. This study describes the first successful enrichment of ammonia-oxidizing archaea from the South West Atlantic, representing the first step on the characterization of this key group in the Santos Basin. Palavras-chave: Nitrosopumilaceae, culture, molecular analysis, nitrogen metabolism, estuary Agência de fomento:Fundação de apoio à Universidade de São Paulo (FUSP) | |||||