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Joseph A Krzycki - One of the best experts on this subject based on the ideXlab platform.
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mtcb a member of the mttb superfamily from the human gut acetogen eubacterium limosum is a cobalamin dependent carnitine demethylase
Journal of Biological Chemistry, 2020Co-Authors: Duncan J Kountz, E J Behrman, Liwen Zhang, Joseph A KrzyckiAbstract:The trimethylamine methyltransferase MttB is the first described member of a superfamily comprising thousands of Microbial Proteins. Most members of the MttB superfamily are encoded by genes that lack the codon for pyrrolysine characteristic of trimethylamine methyltransferases, raising questions about the activities of these Proteins. The superfamily member MtcB is found in the human intestinal isolate Eubacterium limosum ATCC 8486, an acetogen that can grow by demethylation of l-carnitine. Here, we demonstrate that MtcB catalyzes l-carnitine demethylation. When growing on l-carnitine, E. limosum excreted the unusual biological product norcarnitine as well as acetate, butyrate, and caproate. Cellular extracts of E. limosum grown on l-carnitine, but not lactate, methylated cob-(I)alamin or tetrahydrofolate using l-carnitine as methyl donor. MtcB, along with the corrinoid protein MtqC and the methylcorrinoid:tetrahydrofolate methyltransferase MtqA, were much more abundant in E. limosum cells grown on l-carnitine than on lactate. Recombinant MtcB methylates either cob(I)alamin or Co(I)-MtqC in the presence of l-carnitine and, to a much lesser extent, γ-butyrobetaine. Other quaternary amines were not substrates. Recombinant MtcB, MtqC, and MtqA methylated tetrahydrofolate via l-carnitine, forming a key intermediate in the acetogenic Wood-Ljungdahl pathway. To our knowledge, MtcB methylation of cobalamin or Co(I)-MtqC represents the first described mechanism of biological l-carnitine demethylation. The conversion of l-carnitine and its derivative γ-butyrobetaine to trimethylamine by the gut microbiome has been linked to cardiovascular disease. The activities of MtcB and related Proteins in E. limosum might demethylate proatherogenic quaternary amines and contribute to the perceived health benefits of this human gut symbiont.
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mtpb a member of the mttb superfamily from the human intestinal acetogen eubacterium limosum catalyzes proline betaine demethylation
Journal of Biological Chemistry, 2019Co-Authors: Jonathan W Picking, E J Behrman, Liwen Zhang, Joseph A KrzyckiAbstract:The trimethylamine methyltransferase MttB is the founding member of a widely distributed superfamily of Microbial Proteins. Genes encoding most members of the MttB superfamily lack the codon for pyrrolysine that distinguishes previously characterized trimethylamine methyltransferases, leaving the function(s) of most of the enzymes in this superfamily unknown. Here, investigating the MttB family member MtpB from the human intestinal isolate Eubacterium limosum ATCC 8486, an acetogen that excretes N-methyl proline during growth on proline betaine, we demonstrate that MtpB catalyzes anoxic demethylation of proline betaine. MtpB along with MtqC (a corrinoid protein) and MtqA (a methylcorrinoid:tetrahydrofolate methyltransferase) was much more abundant in E. limosum cells grown on proline betaine than on lactate. We observed that recombinant MtpB methylates Co(I)-MtqC in the presence of proline betaine and that other quaternary amines are much less preferred substrates. MtpB, MtqC, and MtqA catalyze tetrahydrofolate methylation with proline betaine, thereby forming a key intermediate in the Wood-Ljungdahl acetogenesis pathway. To our knowledge, MtpB methylation of Co(I)-MtqC for the subsequent methylation of tetrahydrofolate represents the first described anoxic mechanism of proline betaine demethylation. The activities of MtpB and associated Proteins in acetogens or other anaerobes provide a possible mechanism for the production of N-methyl proline by the gut microbiome. MtpB's activity characterized here strengthens the hypothesis that much of the MttB superfamily comprises quaternary amine-dependent methyltransferases.
X Q Zhou - One of the best experts on this subject based on the ideXlab platform.
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effect of dietary energy source and level on nutrient digestibility rumen Microbial protein synthesis and milk performance in lactating dairy cows
Journal of Dairy Science, 2015Co-Authors: X Q Zhou, Y D Zhang, M Zhao, Tao Zhang, Dengpan Bu, Jiaqi WangAbstract:This study was conducted to examine the effects of dietary energy source and level on intake, digestion, rumen Microbial protein synthesis, and milk production in lactating dairy cows, using corn stover as a forage source. Eight multiparous Holstein cows, 4 of which were fitted with rumen cannulas, were evaluated in a replicated 4 × 4 Latin square design, with each period lasting 21 d. The cows were randomly assigned into 4 treatment groups: low-energy (LE) ground corn (GC), LE steam-flaked corn (SFC), high-energy (HE) GC, and HE SFC. Changes to ruminal energy degradation rates were induced by feeding the cows diets of either finely ground corn or SFC as components of diets with the same total energy level. Milk yield, milk protein content and yield, and milk lactose yield all increased in response to higher levels of dietary energy, whereas contents of milk fat and lactose were unaffected. Cows fed HE diets had a higher crude Microbial protein yield and total-tract apparent digestibility than those receiving LE diets. Milk yield, milk protein yield, and Microbial protein yield were also higher when SFC replaced GC as the main energy source for lactating cows fed LE diets. These results suggest that an increased dietary energy level and ruminal degradation rate are beneficial to milk protein production, which we suggest is due to increased yields of Microbial Proteins, when cows are fed corn stover as a dietary forage source.
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effect of dietary energy source and level on nutrient digestibility rumen Microbial protein synthesis and milk performance in lactating dairy cows
Journal of Dairy Science, 2015Co-Authors: X Q Zhou, Y D Zhang, M Zhao, Tao Zhang, D Zhu, J Q WangAbstract:This study was conducted to examine the effects of dietary energy source and level on intake, digestion, rumen Microbial protein synthesis, and milk production in lactating dairy cows, using corn stover as a forage source. Eight multiparous Holstein cows, 4 of which were fitted with rumen cannulas, were evaluated in a replicated 4 × 4 Latin square design, with each period lasting 21 d. The cows were randomly assigned into 4 treatment groups: low-energy (LE) ground corn (GC), LE steam-flaked corn (SFC), high-energy (HE) GC, and HE SFC. Changes to ruminal energy degradation rates were induced by feeding the cows diets of either finely ground corn or SFC as components of diets with the same total energy level. Milk yield, milk protein content and yield, and milk lactose yield all increased in response to higher levels of dietary energy, whereas contents of milk fat and lactose were unaffected. Cows fed HE diets had a higher crude Microbial protein yield and total-tract apparent digestibility than those receiving LE diets. Milk yield, milk protein yield, and Microbial protein yield were also higher when SFC replaced GC as the main energy source for lactating cows fed LE diets. These results suggest that an increased dietary energy level and ruminal degradation rate are beneficial to milk protein production, which we suggest is due to increased yields of Microbial Proteins, when cows are fed corn stover as a dietary forage source.
Daniel Figeys - One of the best experts on this subject based on the ideXlab platform.
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evaluating in vitro culture medium of gut microbiome with orthogonal experimental design and a metaproteomics approach
Journal of Proteome Research, 2018Co-Authors: Xu Zhang, Daniel Figeys, Zhibin Ning, Janice Mayne, David R. Mack, Alain Stintzi, James Butcher, Jasmine I. Moore, Cheng-kang ChiangAbstract:In vitro culture based approaches are time- and cost-effective solutions for rapidly evaluating the effects of drugs or natural compounds against microbiomes. The nutritional composition of the culture medium is an important determinant for effectively maintaining the gut microbiome in vitro. This study combines orthogonal experimental design and a metaproteomics approach to obtaining functional insights into the effects of different medium components on the microbiome. Our results show that the metaproteomic profile respond differently to medium components, including inorganic salts, bile salts, mucin, and short-chain fatty acids. Multifactor analysis of variance further revealed significant main and interaction effects of inorganic salts, bile salts, and mucin on the different functional groups of gut Microbial Proteins. While a broad regulating effect was observed on basic metabolic pathways, different medium components also showed significant modulations on cell wall, membrane, and envelope biogenesis...
Jiaqi Wang - One of the best experts on this subject based on the ideXlab platform.
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effect of dietary energy source and level on nutrient digestibility rumen Microbial protein synthesis and milk performance in lactating dairy cows
Journal of Dairy Science, 2015Co-Authors: X Q Zhou, Y D Zhang, M Zhao, Tao Zhang, Dengpan Bu, Jiaqi WangAbstract:This study was conducted to examine the effects of dietary energy source and level on intake, digestion, rumen Microbial protein synthesis, and milk production in lactating dairy cows, using corn stover as a forage source. Eight multiparous Holstein cows, 4 of which were fitted with rumen cannulas, were evaluated in a replicated 4 × 4 Latin square design, with each period lasting 21 d. The cows were randomly assigned into 4 treatment groups: low-energy (LE) ground corn (GC), LE steam-flaked corn (SFC), high-energy (HE) GC, and HE SFC. Changes to ruminal energy degradation rates were induced by feeding the cows diets of either finely ground corn or SFC as components of diets with the same total energy level. Milk yield, milk protein content and yield, and milk lactose yield all increased in response to higher levels of dietary energy, whereas contents of milk fat and lactose were unaffected. Cows fed HE diets had a higher crude Microbial protein yield and total-tract apparent digestibility than those receiving LE diets. Milk yield, milk protein yield, and Microbial protein yield were also higher when SFC replaced GC as the main energy source for lactating cows fed LE diets. These results suggest that an increased dietary energy level and ruminal degradation rate are beneficial to milk protein production, which we suggest is due to increased yields of Microbial Proteins, when cows are fed corn stover as a dietary forage source.
J Q Wang - One of the best experts on this subject based on the ideXlab platform.
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effect of dietary energy source and level on nutrient digestibility rumen Microbial protein synthesis and milk performance in lactating dairy cows
Journal of Dairy Science, 2015Co-Authors: X Q Zhou, Y D Zhang, M Zhao, Tao Zhang, D Zhu, J Q WangAbstract:This study was conducted to examine the effects of dietary energy source and level on intake, digestion, rumen Microbial protein synthesis, and milk production in lactating dairy cows, using corn stover as a forage source. Eight multiparous Holstein cows, 4 of which were fitted with rumen cannulas, were evaluated in a replicated 4 × 4 Latin square design, with each period lasting 21 d. The cows were randomly assigned into 4 treatment groups: low-energy (LE) ground corn (GC), LE steam-flaked corn (SFC), high-energy (HE) GC, and HE SFC. Changes to ruminal energy degradation rates were induced by feeding the cows diets of either finely ground corn or SFC as components of diets with the same total energy level. Milk yield, milk protein content and yield, and milk lactose yield all increased in response to higher levels of dietary energy, whereas contents of milk fat and lactose were unaffected. Cows fed HE diets had a higher crude Microbial protein yield and total-tract apparent digestibility than those receiving LE diets. Milk yield, milk protein yield, and Microbial protein yield were also higher when SFC replaced GC as the main energy source for lactating cows fed LE diets. These results suggest that an increased dietary energy level and ruminal degradation rate are beneficial to milk protein production, which we suggest is due to increased yields of Microbial Proteins, when cows are fed corn stover as a dietary forage source.