Profiling of d-alanine production by the microbial isolates of rat gut microbiota.
FASEB J
; 36(8): e22446, 2022 08.
Article
en En
| MEDLINE
| ID: mdl-35816159
ABSTRACT
d-alanine (d-Ala) and several other d-amino acids (d-AAs) act as hormones and neuromodulators in nervous and endocrine systems. Unlike the endogenously synthesized d-serine in animals, d-Ala may be from exogenous sources, e.g., diet and intestinal microorganisms. However, it is unclear if the capability to produce d-Ala and other d-AAs varies among different microbial strains in the gut. We isolated individual microorganisms of rat gut microbiota and profiled their d-AA production in vitro, focusing on d-Ala. Serial dilutions of intestinal contents from adult male rats were plated on agar to obtain clonal cultures. Using MALDI-TOF MS for rapid strain typing, we identified 38 unique isolates, grouped into 11 species based on 16S rRNA gene sequences. We then used two-tier screening to profile bacterial d-AA production, combining a d-amino acid oxidase-based enzymatic assay for rapid assessment of non-acidic d-AA amount and chiral LC-MS/MS to quantify individual d-AAs, revealing 19 out of the 38 isolated strains as d-AA producers. LC-MS/MS analysis of the eight top d-AA producers showed high levels of d-Ala in all strains tested, with substantial inter- and intra-species variations. Though results from the enzymatic assay and LC-MS/MS analysis aligned well, LC-MS/MS further revealed the existence of d-glutamate and d-aspartate, which are poor substrates for this enzymatic assay. We observed large inter- and intra-species variation of d-AA production profiles from rat gut microbiome species, demonstrating the importance of chemical profiling of gut microbiota in addition to sequencing, furthering the idea that microbial metabolites modulate host physiology.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Microbioma Gastrointestinal
Límite:
Animals
Idioma:
En
Revista:
FASEB J
Asunto de la revista:
BIOLOGIA
/
FISIOLOGIA
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos