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Zünd JN, Plüss S, Mujezinovic D, Menzi C, von Bieberstein PR, de Wouters T, Lacroix C, Leventhal GE, Pugin B. A flexible high-throughput cultivation protocol to assess the response of individuals' gut microbiota to diet-, drug-, and host-related factors. ISME Commun 2024; 4:ycae035. [PMID: 38562261 PMCID: PMC10982853 DOI: 10.1093/ismeco/ycae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/13/2023] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
The anaerobic cultivation of fecal microbiota is a promising approach to investigating how gut microbial communities respond to specific intestinal conditions and perturbations. Here, we describe a flexible protocol using 96-deepwell plates to cultivate stool-derived gut microbiota. Our protocol aims to address gaps in high-throughput culturing in an anaerobic chamber. We characterized the influence of the gas phase on the medium chemistry and microbial physiology and introduced a modular medium preparation process to enable the testing of several conditions simultaneously. Furthermore, we identified a medium formulation that maximized the compositional similarity of ex vivo cultures and donor microbiota while limiting the bloom of Enterobacteriaceae. Lastly, we validated the protocol by demonstrating that cultivated fecal microbiota responded similarly to dietary fibers (resistant dextrin, soluble starch) and drugs (ciprofloxacin, 5-fluorouracil) as reported in vivo. This high-throughput cultivation protocol has the potential to facilitate culture-dependent studies, accelerate the discovery of gut microbiota-diet-drug-host interactions, and pave the way to personalized microbiota-centered interventions.
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Affiliation(s)
- Janina N Zünd
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
| | - Serafina Plüss
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
| | - Denisa Mujezinovic
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
| | - Carmen Menzi
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
- PharmaBiome AG, 8952 Schlieren, Switzerland
| | - Philipp R von Bieberstein
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
- PharmaBiome AG, 8952 Schlieren, Switzerland
| | | | - Christophe Lacroix
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
| | | | - Benoit Pugin
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
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Pugin B, Plüss S, Mujezinovic D, Nielsen RC, Lacroix C. Optimized UV-Spectrophotometric Assay to Screen Bacterial Uricase Activity Using Whole Cell Suspension. Front Microbiol 2022; 13:853735. [PMID: 35495677 PMCID: PMC9043897 DOI: 10.3389/fmicb.2022.853735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/10/2022] [Indexed: 11/13/2022] Open
Abstract
Uricase catalyzes the conversion of uric acid into allantoin with concomitant reduction of molecular oxygen to hydrogen peroxide. In humans, uricase is not functional, thereby predisposing individuals to hyperuricemia, a metabolic disturbance associated with gout, chronic kidney disorders, and cardiovascular diseases. The efficacy of current therapies to treat hyperuricemia is limited, and novel approaches are therefore desired, for instance using uricase-expressing probiotic strains. Here, we evaluated UV-spectrophotometric and H2O2-based fluorescent assays to enable the rapid identification of uricase activity in a broad panel of lactobacilli, Bacillus, and Bifidobacterium species. We highlighted abiotic (medium composition and mode of sterilization) and biotic (H2O2-producing strains) factors impacting the measurements' accuracy, and reported on the stepwise optimization of a simple, fast, and robust high-throughput UV-spectrophotometric method to screen uricase activity using whole bacterial suspension, thereby assessing both cell-associated and extracellular activity. The validity of the optimized assay, based on the monitoring of uric acid degradation at 300 nm, was confirmed via liquid chromatography. Finally, a panel of 319 Qualified Presumption of Safety (QPS) strains of lactobacilli (18 species covering nine genera), Bacillus (three species), and Bifidobacterium (four species) were screened for uricase activity using the optimized method. All 319 strains, but the positive control Bacillus sp. DSM 1306, were uricase-negative, indicating that this activity is rare among these genera, especially in isolates from food or feces. Altogether, the UV-spectrophotometric high-throughput assay based on whole bacterial suspension reported here can be used to rapidly screen large microbial collections, by simultaneously detecting cell-associated and extracellular uricase activity, thereby accelerating the identification of uricolytic strains with therapeutic potential to treat hyperuricemia.
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Affiliation(s)
- Benoit Pugin
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Serafina Plüss
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Denisa Mujezinovic
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | | | - Christophe Lacroix
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
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Otaru N, Ye K, Mujezinovic D, Berchtold L, Constancias F, Cornejo FA, Krzystek A, de Wouters T, Braegger C, Lacroix C, Pugin B. GABA Production by Human Intestinal Bacteroides spp.: Prevalence, Regulation, and Role in Acid Stress Tolerance. Front Microbiol 2021; 12:656895. [PMID: 33936013 PMCID: PMC8082179 DOI: 10.3389/fmicb.2021.656895] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/24/2021] [Indexed: 12/11/2022] Open
Abstract
The high neuroactive potential of metabolites produced by gut microbes has gained traction over the last few years, with metagenomic-based studies suggesting an important role of microbiota-derived γ-aminobutyric acid (GABA) in modulating mental health. Emerging evidence has revealed the presence of the glutamate decarboxylase (GAD)-encoding gene, a key enzyme to produce GABA, in the prominent human intestinal genus Bacteroides. Here, we investigated GABA production by Bacteroides in culture and metabolic assays combined with comparative genomics and phylogenetics. A total of 961 Bacteroides genomes were analyzed in silico and 17 metabolically and genetically diverse human intestinal isolates representing 11 species were screened in vitro. Using the model organism Bacteroides thetaiotaomicron DSM 2079, we determined GABA production kinetics, its impact on milieu pH, and we assessed its role in mitigating acid-induced cellular damage. We showed that the GAD-system consists of at least four highly conserved genes encoding a GAD, a glutaminase, a glutamate/GABA antiporter, and a potassium channel. We demonstrated a high prevalence of the GAD-system among Bacteroides with 90% of all Bacteroides genomes (96% in human gut isolates only) harboring all genes of the GAD-system and 16 intestinal Bacteroides strains producing GABA in vitro (ranging from 0.09 to 60.84 mM). We identified glutamate and glutamine as precursors of GABA production, showed that the production is regulated by pH, and that the GAD-system acts as a protective mechanism against acid stress in Bacteroides, mitigating cell death and preserving metabolic activity. Our data also indicate that the GAD-system might represent the only amino acid-dependent acid tolerance system in Bacteroides. Altogether, our results suggest an important contribution of Bacteroides in the regulation of the GABAergic system in the human gut.
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Affiliation(s)
- Nize Otaru
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.,Nutrition Research Unit, University Children's Hospital Zürich, Zürich, Switzerland
| | - Kun Ye
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Denisa Mujezinovic
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Laura Berchtold
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.,PharmaBiome AG, Zürich, Switzerland
| | - Florentin Constancias
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Fabián A Cornejo
- Max Planck Unit for the Science of Pathogens, Berlin, Germany.,Laboratory of Molecular Microbiology, Faculty of Chemistry and Biology, University of Santiago, Santiago, Chile
| | - Adam Krzystek
- Laboratory of Human Nutrition, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | | | - Christian Braegger
- Nutrition Research Unit, University Children's Hospital Zürich, Zürich, Switzerland
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Benoit Pugin
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
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