| Literature DB >> 34066922 |
Ana López-Moreno1,2, Alfonso Torres-Sánchez1,2, Inmaculada Acuña2,3, Antonio Suárez2,3, Margarita Aguilera1,2,4.
Abstract
Human gut microbiota harbors numerous microbial species with molecular enzymatic potential that impact on the eubiosis/dysbiosis and health/disease balances. Microbiota species isolation and description of their specific molecular features remain largely unexplored. In the present study, we focused on the cultivation and selection of species able to tolerate or biodegrade the endocrine disruptor bisphenol A (BPA), a xenobiotic extensively found in food plastic containers. Chemical xenobiotic addition methods for the directed isolation, culturing, Whole Genome Sequencing (WGS), phylogenomic identification, and specific gene-encoding searches have been applied to isolate microorganisms, assess their BPA metabolization potential, and describe encoded catabolic pathways. BPA-tolerant strains were isolated from 30% of infant fecal microbial culture libraries analyzed. Most isolated strains were phylogenetically related to the operational taxonomic group Bacillus amyloliquefaciens spp. Importantly, WGS analysis of microbial representative strain, Bacillus sp. AM1 identified the four complete molecular pathways involved on BPA degradation indicating its versatility and high potential to degrade BPA. Pathways for Exopolysaccharide (EPS) and Polyhydroxyalkanates (PHA) biopolymer synthesis were also identified and phenotypically confirmed by transmission electronic microscopy (TEM). These microbial biopolymers could generally contribute to capture and/or deposit xenobiotics.Entities:
Keywords: Bacillus; EPS; PHA; bisphenols; enzymes; human microbiota; molecular pathways
Year: 2021 PMID: 34066922 PMCID: PMC8125285 DOI: 10.3390/ijms22094952
Source DB: PubMed Journal: Int J Mol Sci ISSN: 1422-0067 Impact factor: 5.923
Figure 1A phylogenomic tree based on partial 16S RNA gene (Table S1) of isolated strains of Bacillus sp. and closely related species. The tree was inferred by the maximum-likelihood method. The species and strain names are shown, and accession numbers are indicated in parentheses. Bootstrap values after 1000 resamplings are indicated at branch nodes. Bar: 0.0020 nucleotide substitution per site.
Figure 2(a) Colony morphology of Bacillus sp. in MRS medium; (b) Image of Bacillus sp. AM1 by TEM showing lipidic PHA granules, EPS, and Endocrine disruptor ED-BPA. 1µm scale; (c) BPA degradation curve by Bacillus sp. AM1. BPA biodegradation capacity was tested in TSB liquid cultures of Bacillus sp. AM1 exposed to 25 ppb concentration of BPA at 30ºC for 72h (LC-MS/MS system for quantification).
Results derived from the enzymatic analysis of Bacillus sp. AM1.
| Enzyme Test | Microorganisms | |||||
|---|---|---|---|---|---|---|
|
|
| |||||
| Starch | + | + | + | ++ | ++ | ++ |
| Carboxymethylcelulose | − | − | − | − | − | − |
| Gelatine | − | − | − | − | − | − |
| Inuline | + | − | − | − | + | + |
| Tween 80 | − | + | + | − | − | − |
| DNase | ++ | + | + | − | − | − |
Antibiotic sensitivity testing.
| Antibiotic | Concentration | Resistance (R) | Zone inhibition |
|---|---|---|---|
| Ampicillin | 10 | R | - |
| Amikacin | 30 | S | 14 |
| Ceftazidime | 30 | R | - |
| Ciprofloxacin | 5 | S | 40 |
| Chloramphenicol | 30 | S | 42 |
| Clindamycin | 2 | S | 22 |
| Erythromycin | 15 | S | 25 |
| Gentamicin | 10 | S | 22 |
| Imipenem | 10 | S | 50 |
| Penicillin | 10 | R | - |
| Rifampicin | 30 | S | 29 |
| Vancomycin | 30 | S | 22 |
| Kanamycin | 30 | S | 19 |
| Streptomycin | 10 | R | - |
| Tetracycline | 30 | S | 17 |
| Co-Trimoxazole | 25 | S | 39 |
| Amoxicillin/ | 20/10 | R | - |
Figure 3Phylogenomic trees based on gene sequences of Bacillus sp. AM1: (a) 16S RNA gene; (b) gyrA gene, similarity distances were computed using JTT’s model; (c) rpoB gene, similarity distances were computed using JTT’s model. The tree was inferred by the maximum-likelihood method. The species and strain names are shown, and accession numbers are indicated in parentheses. Bootstrap values shown after 1000 resamplings.
Figure 4Proposed Biodegradation Pathways of BPA based on the WGS analysis of Bacillus sp. AM1: Reaction steps, Enzymes, EC number, protein ID, and specific genes loci.