In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 88, No. 3 ( 2022-02-08)
Abstract:
As the most abundant d- amino acid (DAA) in the ocean, d- alanine ( d -Ala) is a key component of peptidoglycan in the bacterial cell wall. However, the underlying mechanisms of bacterial metabolization of d- Ala through the microbial food web remain largely unknown. In this study, the metabolism of d- Ala by marine bacterium Pseudoalteromonas sp. strain CF6-2 was investigated. Based on genomic, transcriptional, and biochemical analyses combined with gene knockout, d- Ala aminotransferase was found to be indispensable for the catabolism of d- Ala in strain CF6-2. Investigation on other marine bacteria also showed that d- Ala aminotransferase gene is a reliable indicator for their ability to utilize d- Ala. Bioinformatic investigation revealed that d- Ala aminotransferase sequences are prevalent in genomes of marine bacteria and metagenomes, especially in seawater samples, and Gammaproteobacteria represents the predominant group containing d- Ala aminotransferase. Thus, Gammaproteobacteria is likely the dominant group to utilize d- Ala via d- Ala aminotransferase to drive the recycling and mineralization of d- Ala in the ocean. IMPORTANCE As the most abundant d- amino acid in the ocean, d- Ala is a component of the marine DON (dissolved organic nitrogen) pool. However, the underlying mechanism of bacterial metabolization of d- Ala to drive the recycling and mineralization of d- Ala in the ocean is still largely unknown. The results in this study showed that d- Ala aminotransferase is specific and indispensable for d- Ala catabolism in marine bacteria and that marine bacteria containing d- Ala aminotransferase genes are predominantly Gammaproteobacteria widely distributed in global oceans. This study reveals marine d- Ala-utilizing bacteria and the mechanism of their metabolization of d- Ala. The results shed light on the mechanisms of recycling and mineralization of d- Ala driven by bacteria in the ocean, which are helpful in understanding oceanic microbial-mediated nitrogen cycle.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/aem.02219-21
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2022
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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