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
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
Project description:Lactobacillus reuteri has been shown to encode a vitamin B12 biosynthesis pathway that is phylogenetically related to the one present in some representatives of gamma-proteobacteria such as Salmonella and Yersinia. Here we present evidence supporting that the similarities between these otherwise unrelated organisms extend to their regulatory mechanisms. Keywords: cell type comparison Loop design
Project description:Lactobacillus reuteri has been shown to encode a vitamin B12 biosynthesis pathway that is phylogenetically related to the one present in some representatives of gamma-proteobacteria such as Salmonella and Yersinia. Here we present evidence supporting that the similarities between these otherwise unrelated organisms extend to their regulatory mechanisms. Keywords: cell type comparison
Project description:Vitamin B12 is an essential micronutrient that functions in two metabolic pathways: the canonical propionate breakdown pathway and the methionine/S-adenosylmethionine (Met/SAM) cycle. In Caenorhabditis elegans, low vitamin B12, or genetic perturbation of the canonical propionate breakdown pathway results in propionate accumulation and the transcriptional activation of a propionate shunt pathway. This propionate-dependent mechanism requires nhr-10 and is referred to as “B12-mechanism-I”. Here, we report that vitamin B12 represses the expression of Met/SAM cycle genes by a propionate-independent mechanism we refer to as “B12-mechanism-II”. This mechanism is activated by perturbations in the Met/SAM cycle, genetically or due to low dietary vitamin B12. B12-mechanism-II requires nhr-114 to activate Met/SAM cycle gene expression, the vitamin B12 transporter, pmp-5, and adjust influx and efflux of the cycle by activating msra-1 and repressing cbs-1, respectively. Taken together, Met/SAM cycle activity is sensed and transcriptionally adjusted to be in a tight metabolic regime.
Project description:Vitamin B12 is an essential micronutrient that functions in two metabolic pathways: the canonical propionate breakdown pathway and the methionine/S-adenosylmethionine (Met/SAM) cycle. In Caenorhabditis elegans, low vitamin B12, or genetic perturbation of the canonical propionate breakdown pathway results in propionate accumulation and the transcriptional activation of a propionate shunt pathway. This propionate-dependent mechanism requires nhr-10 and is referred to as “B12-mechanism-I”. Here, we report that vitamin B12 represses the expression of Met/SAM cycle genes by a propionate-independent mechanism we refer to as “B12-mechanism-II”. This mechanism is activated by perturbations in the Met/SAM cycle, genetically or due to low dietary vitamin B12. B12-mechanism-II requires nhr-114 to activate Met/SAM cycle gene expression, the vitamin B12 transporter, pmp-5, and adjust influx and efflux of the cycle by activating msra-1 and repressing cbs-1, respectively. Taken together, Met/SAM cycle activity is sensed and transcriptionally adjusted to be in a tight metabolic regime.
2020-06-05 | GSE151846 | GEO
Project description:Food quality improvement through vitamin B12-producing bacteria.
Project description:Vitamin B12 (B12) is an important cofactor in mycobacterial metabolism, and some pathogenic mycobacteria need to obtain it from the host. In this study, we investigated the transport of vitamin B12 in Mycobacterium marinum. We identified a transcriptor regulator that could be potentially involved in the uptake process. RNA sequencing analysis were performed in order to elucidate the regulon of this new transcriptor.
Project description:The two C. elegans natural microbiota isolates Pseudomonas lurida MYb11 and Pseudomonas fluorescens MYb115 protect the host against pathogens through distinct mechanisms. While P. lurida produces an antimicrobial compound and directly inhibits pathogen growth, P. fluorescens MYb115 protects the host without affecting pathogen growth. It is unknown how these two protective microbes affect host biological processes. We used a proteomics approach to elucidate the C. elegans response to MYb11 and MYb115. We found that both Pseudomonas isolates increase vitellogenin protein production in adult day 1 animals, which confirms previous findings on the effect of microbiota on C. elegans reproductive timing. Moreover, the C. elegans responses to MYb11 and MYb115 exhibit common signatures with the response to other vitamin B12-producing bacteria, emphasizing the importance of vitamin B12 in C. elegans-microbe metabolic interactions.