B12-ABP labeling of Bacteroides thetaiotaomicron
Ontology highlight
ABSTRACT:
INSTRUMENT(S):
ORGANISM(S): Bacteroides Thetaiotaomicron (strain Atcc 29148 / Dsm 2079 / Nctc 10582 / E50 / Vpi-5482)
SUBMITTER: 
Matthew Monroe
LAB HEAD: Aaron Wright
PROVIDER: PXD015052 | Pride | 2022-01-11
REPOSITORIES: Pride
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Project description:We previously observed in mice that Bacteroides thetaiotaomicron (B. theta) significantly increased in abundance in the gut microbiome of mice when mice were fed egg and yeast dietary protein sources. We also observed that B. theta was expressing proteins previously connected to growth on mucin glycans when mice were fed an egg-white diet. To confirm that the bacterium were actually responding to the protein sources, we grew it in vitro using a defined medium, where the sole carbon source was dietary protein, mucin, or glucose. Our controls were glucose and mucin, and our experimental protein sources were soy protein, egg-white protein, and Torula yeast protein. We grew four B. theta cultures per carbon source statically at 37°C in a Coy anaerobic chamber (2.5 % H2 /10 % CO2 /88.5 % N2) in minimal medium (100 mM KH2PO4, 8.5 mM [NH2]4SO4, 15 mM NaCl, 5.8 μM vitamin K3, 1.44 μM FeSO4⋅7H2O, 1 mM MgCl2, 1.9 μM hematin, 0.2 mM L-histidine, 3.69 nM vitamin B12, 208 μM L-cysteine, and 7.2 μM CaCl2⋅2H2O) with one of the above mentioned nutrients added at 0.5% (wt/v) concentration. In order to aid the solubilization of the dietary proteins, we pre-prepared the proteins in 200 mM NaOH at 37°C for four days, the glucose control was also dissolved in 200 mM NaOH. After 8 hours, we enumerated CFUs to confirm growth, and we pelleted cells by centrifuging at 4,000 g for 10 minutes. We then removed the supernatant and froze the pellets at -80°C within 30 minutes.
2024-12-18 | PXD050296 | Pride
Project description:To examine the protective effect of B12 on myocardial ischemia/reperfusion injury and figure out the mechanism of B12.
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Project description:Vitamin B12 (cobalamin) is the most complex vitamin and essential for many human gut microbes. However, cobalamin is synthesized only by a limited number of bacteria, making many gut microbes dependent on scavenging to meet their cobalamin requirements. Since bacterial densities in the gut are extremely high, competition for cobalamin is severe, making it a keystone micronutrient that shapes human gut microbial communities. Contrasting with Enterobacteria like Escherichia coli which only have one outer membrane (OM) transporter dedicated to B12 uptake (BtuB), members of the dominant genus Bacteroides often encode several vitamin B12 OM transporters together with a conserved array of surface-exposed B12-binding lipoproteins. Here we show, via X-ray crystallography, cryogenic electron microscopy (cryoEM) and molecular dynamics (MD) simulations, that the BtuB1 and BtuB2 transporters from the prominent human gut bacterium Bacteroides thetaiotaomicron form stable complexes with the surface-exposed lipoproteins BtuG1 and BtuG2. The lipoproteins cap the external surface of their cognate BtuB transporter and, when open, capture B12 via electrostatic attraction. After B12 capture, the BtuG lid closes, with concomitant transfer of the vitamin to the BtuB transporter and subsequent transport. We propose that TonB-dependent, lipoprotein-assisted small molecule uptake is a general feature of Bacteroides spp. that is important for the success of this genus in colonising the human gut.
2023-10-18 | PXD038230 | Pride
Project description:The environment of gut bacteria is extremely dynamic. Environmental conditions were shown to affect microbial composition, however, their effects on bacterial functionality (e.g., immune-modulation activity) are mostly overlooked. Distinct strains of the same species, and even the same bacterial strain, may have different effects on the immune system depending on their growth environment. Therefore, studying the functionality of strains, under different conditions, is crucial. We analyzed functional alterations in the gut symbiont Bacteroides thetaiotaomicron (B. theta) under different diets in humans, under sugar consumption in mice, and in response to 190 different carbon sources in vitro. Dietary alterations affected the orientation of phase variable promoters in B. theta in humans, in vivo and in vitro and altered B. theta’s proteome and immune-modulatory functionality. Studying the effects of dietary components on the immune-modulatory functionalities of key members of the gut microbiota will allow tailored dietary recommendations to patients.
2025-05-04 | PXD060215 | Pride
Project description:Rationale: Low B12 has been shown to play an important role in the prediction of metabolic risk, but its significance and mechanism in the development of adiposity and adipose tissue dysfunction is largely unknown. Objective: To investigate the role of B12 and folic acid in the development of adipocyte dysfunction. Methods and Results: Microarray analysis of human adipocytes (CHUB-S7 cell line) cultured and differentiated in customised media with varying concentrations of B12 and folic acid led to the identification of two important pathways: cholesterol synthesis and unfolded protein response (UPR). Adipocytes cultured in media with low B12 (150 pmol/L) or no B12 had increased intracellular total cholesterol, higher secreted homocysteine levels, induced UPR and reduced glucose uptake capacity compared to adipocytes cultured in normal media with higher B12. The folate concentrations had either no or little effect on the measured functions. Further analysis of these adipocytes for overall DNA methylation showed that the promoter regions of sterol regulatory element-binding transcription factor 1 (SREBF1) and low density lipoprotein receptor (LDLR) were hypomethylated in the low and no B12 conditions. The SREB proteins (SREBP1 and 2) and mRNA expressions (SREBF1 and LDLR) were also increased in the same conditions. Conclusion: The data suggest that low B12 can lead to adipocyte dysfunction by inducing excess cholesterol biosynthesis, homocysteine production and induction of UPR and overall adipocyte dysfunction. Both of these pathways and adipocyte dysfunction play a significant role in the development of cardiovascular diseases. Independent replicate samples of the human adipocyte cell line CHUB-S7 were treated with four different concentrations of B12 and folate.
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Project description:Astrocytes express a vitamin B12 uptake receptor, CD320/TCblR, that is regulated by S1P1 signaling. In search of genes controlled under B12 deficiency in astrocytes, we employed RNA-seq using RNA of astrocytes cultured in normal or B12 deficient media.
2022-05-17 | GSE99113 | GEO
Project description:Background: Chronic stress significantly contributes to mood- and anxiety disorders. Previous data suggest a correlative connection between vitamin B12 supplementation, depression, and stress resilience. However, the underlying mechanisms are still poorly understood. Methods: Using the chronic variable stress mouse model coupled with RNA-sequencing, we determined vitamin B12-induced transcriptional changes related to stress resilience. By viral-mediated gene transfer and in vivo epigenome editing, we reveal a functional pathway linking vitamin B12, DNA methylation, and depressive-like symptoms. Results: We identified Transthyretin (Ttr) as a sex-specific key target of vitamin B12 action in chronic stress. Accordingly, TTR expression was increased postmortem in the prefrontal cortex of male, but not female, depressed patients. Virally altered Ttr in the prefrontal cortex functionally contributed to stress- and depression-related behaviors, changes in dendritic spine morphology, and gene expression. In stressed mice, vitamin B12 reduced DNAme in the Ttr promoter region. Importantly, using in vivo epigenome editing to alter DNAme in the brains of living mice for the first time, we establish a direct causal link between DNAme on Ttr and stress-associated behaviors. Discussion: In summary, using state-of-the-art techniques, this study uncovers a mechanistic link between cobalamin supplementation, Ttr, and markers of chronic stress and depression, encouraging further studies into dietary interventions for mood disorders.
2024-05-13 | GSE267047 | GEO
Project description:Recent functional genomics and genome-scale modeling approaches indicated that B12 production in Lactobacillus reuteri could be improved by medium optimization. Here we show that a series of systematic single amino acid omissions could significantly modulate the production of B12 from nearly undetectable levels (by isoleucine omission) to 20-fold higher than previously reported through omission of cysteine. We analyzed by cDNA microarray experiments the transcriptional response of L. reuteri to the medium lacking cysteine. These results supported the observed high B12 production and provided new avenues for future improvement of production of vitamin B12. Keywords: cell type comparison
2008-10-31 | GSE13391 | GEO
Project description:Background: Chronic stress significantly contributes to mood- and anxiety disorders. Previous data suggest a correlative connection between vitamin B12 supplementation, depression, and stress resilience. However, the underlying mechanisms are still poorly understood. Methods: Using the chronic variable stress mouse model coupled with RNA-sequencing, we determined vitamin B12-induced transcriptional changes related to stress resilience. By viral-mediated gene transfer and in vivo epigenome editing, we reveal a functional pathway linking vitamin B12, DNA methylation, and depressive-like symptoms. Results: We identified Transthyretin (Ttr) as a sex-specific key target of vitamin B12 action in chronic stress. Accordingly, TTR expression was increased postmortem in the prefrontal cortex of male, but not female, depressed patients. Virally altered Ttr in the prefrontal cortex functionally contributed to stress- and depression-related behaviors, changes in dendritic spine morphology, and gene expression. In stressed mice, vitamin B12 reduced DNAme in the Ttr promoter region. Importantly, using in vivo epigenome editing to alter DNAme in the brains of living mice for the first time, we establish a direct causal link between DNAme on Ttr and stress-associated behaviors. Discussion: In summary, using state-of-the-art techniques, this study uncovers a mechanistic link between cobalamin supplementation, Ttr, and markers of chronic stress and depression, encouraging further studies into dietary interventions for mood disorders.
2024-05-18 | GSE267339 | GEO
Project description:Recent functional genomics and genome-scale modeling approaches indicated that B12 production in Lactobacillus reuteri could be improved by medium optimization. Here we show that a series of systematic single amino acid omissions could significantly modulate the production of B12 from nearly undetectable levels (by isoleucine omission) to 20-fold higher than previously reported through omission of cysteine. We analyzed by cDNA microarray experiments the transcriptional response of L. reuteri to the medium lacking cysteine. These results supported the observed high B12 production and provided new avenues for future improvement of production of vitamin B12. Keywords: cell type comparison loop design
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