Yeoman CJ

References (5)

Title : Xylan degradation by the human gut Bacteroides xylanisolvens XB1A(T) involves two distinct gene clusters that are linked at the transcriptional level - Despres_2016_BMC.Genomics_17_326
Author(s) : Despres J , Forano E , Lepercq P , Comtet-Marre S , Jubelin G , Chambon C , Yeoman CJ , Berg Miller ME , Fields CJ , Martens E , Terrapon N , Henrissat B , White BA , Mosoni P
Ref : BMC Genomics , 17 :326 , 2016
Abstract : BACKGROUND: Plant cell wall (PCW) polysaccharides and especially xylans constitute an important part of human diet. Xylans are not degraded by human digestive enzymes in the upper digestive tract and therefore reach the colon where they are subjected to extensive degradation by some members of the symbiotic microbiota. Xylanolytic bacteria are the first degraders of these complex polysaccharides and they release breakdown products that can have beneficial effects on human health. In order to understand better how these bacteria metabolize xylans in the colon, this study was undertaken to investigate xylan breakdown by the prominent human gut symbiont Bacteroides xylanisolvens XB1A(T). RESULTS: Transcriptomic analyses of B. xylanisolvens XB1A(T) grown on insoluble oat-spelt xylan (OSX) at mid- and late-log phases highlighted genes in a polysaccharide utilization locus (PUL), hereafter called PUL 43, and genes in a fragmentary remnant of another PUL, hereafter referred to as rPUL 70, which were highly overexpressed on OSX relative to glucose. Proteomic analyses supported the up-regulation of several genes belonging to PUL 43 and showed the important over-production of a CBM4-containing GH10 endo-xylanase. We also show that PUL 43 is organized in two operons and that the knockout of the PUL 43 sensor/regulator HTCS gene blocked the growth of the mutant on insoluble OSX and soluble wheat arabinoxylan (WAX). The mutation not only repressed gene expression in the PUL 43 operons but also repressed gene expression in rPUL 70. CONCLUSION: This study shows that xylan degradation by B. xylanisolvens XB1A(T) is orchestrated by one PUL and one PUL remnant that are linked at the transcriptional level. Coupled to studies on other xylanolytic Bacteroides species, our data emphasize the importance of one peculiar CBM4-containing GH10 endo-xylanase in xylan breakdown and that this modular enzyme may be used as a functional marker of xylan degradation in the human gut. Our results also suggest that B. xylanisolvens XB1A(T) has specialized in the degradation of xylans of low complexity. This functional feature may provide a niche to all xylanolytic bacteria harboring similar PULs. Further functional and ecological studies on fibrolytic Bacteroides species are needed to better understand their role in dietary fiber degradation and their impact on intestinal health.
ESTHER : Despres_2016_BMC.Genomics_17_326
PubMedSearch : Despres_2016_BMC.Genomics_17_326
PubMedID: 27142817

Title : Biochemical characterization and relative expression levels of multiple carbohydrate esterases of the xylanolytic rumen bacterium Prevotella ruminicola 23 grown on an ester-enriched substrate - Kabel_2011_Appl.Environ.Microbiol_77_5671
Author(s) : Kabel MA , Yeoman CJ , Han Y , Dodd D , Abbas CA , de Bont JA , Morrison M , Cann IK , Mackie RI
Ref : Applied Environmental Microbiology , 77 :5671 , 2011
Abstract : We measured expression and used biochemical characterization of multiple carbohydrate esterases by the xylanolytic rumen bacterium Prevotella ruminicola 23 grown on an ester-enriched substrate to gain insight into the carbohydrate esterase activities of this hemicellulolytic rumen bacterium. The P. ruminicola 23 genome contains 16 genes predicted to encode carbohydrate esterase activity, and based on microarray data, four of these were upregulated >2-fold at the transcriptional level during growth on an ester-enriched oligosaccharide (XOS(FA,Ac)) from corn relative to a nonesterified fraction of corn oligosaccharides (AXOS). Four of the 16 esterases (Xyn10D-Fae1A, Axe1-6A, AxeA1, and Axe7A), including the two most highly induced esterases (Xyn10D-Fae1A and Axe1-6A), were heterologously expressed in Escherichia coli, purified, and biochemically characterized. All four enzymes showed the highest activity at physiologically relevant pH (6 to 7) and temperature (30 to 40 degrees C) ranges. The P. ruminicola 23 Xyn10D-Fae1A (a carbohydrate esterase [CE] family 1 enzyme) released ferulic acid from methylferulate, wheat bran, corn fiber, and XOS(FA,Ac), a corn fiber-derived substrate enriched in O-acetyl and ferulic acid esters, but exhibited negligible activity on sugar acetates. As expected, the P. ruminicola Axe1-6A enzyme, which was predicted to possess two distinct esterase family domains (CE1 and CE6), released ferulic acid from the same substrates as Xyn10D-Fae1 and was also able to cleave O-acetyl ester bonds from various acetylated oligosaccharides (AcXOS). The P. ruminicola 23 AxeA1, which is not assigned to a CE family, and Axe7A (CE7) were found to be acetyl esterases that had activity toward a broad range of mostly nonpolymeric acetylated substrates along with AcXOS. All enzymes were inhibited by the proximal location of other side groups like 4-O-methylglucuronic acid, ferulic acid, or acetyl groups. The unique diversity of carbohydrate esterases in P. ruminicola 23 likely gives it the ability to hydrolyze substituents on the xylan backbone and enhances its capacity to efficiently degrade hemicellulose.
ESTHER : Kabel_2011_Appl.Environ.Microbiol_77_5671
PubMedSearch : Kabel_2011_Appl.Environ.Microbiol_77_5671
PubMedID: 21742923
Gene_locus related to this paper: prer2-axea1 , prer2-axfa

Title : Comparative genomics of Gardnerella vaginalis strains reveals substantial differences in metabolic and virulence potential - Yeoman_2010_PLoS.One_5_e12411
Author(s) : Yeoman CJ , Yildirim S , Thomas SM , Durkin AS , Torralba M , Sutton G , Buhay CJ , Ding Y , Dugan-Rocha SP , Muzny DM , Qin X , Gibbs RA , Leigh SR , Stumpf R , White BA , Highlander SK , Nelson KE , Wilson BA
Ref : PLoS ONE , 5 :e12411 , 2010
Abstract : BACKGROUND: Gardnerella vaginalis is described as a common vaginal bacterial species whose presence correlates strongly with bacterial vaginosis (BV). Here we report the genome sequencing and comparative analyses of three strains of G. vaginalis. Strains 317 (ATCC 14019) and 594 (ATCC 14018) were isolated from the vaginal tracts of women with symptomatic BV, while Strain 409-05 was isolated from a healthy, asymptomatic individual with a Nugent score of 9. PRINCIPAL FINDINGS: Substantial genomic rearrangement and heterogeneity were observed that appeared to have resulted from both mobile elements and substantial lateral gene transfer. These genomic differences translated to differences in metabolic potential. All strains are equipped with significant virulence potential, including genes encoding the previously described vaginolysin, pili for cytoadhesion, EPS biosynthetic genes for biofilm formation, and antimicrobial resistance systems, We also observed systems promoting multi-drug and lantibiotic extrusion. All G. vaginalis strains possess a large number of genes that may enhance their ability to compete with and exclude other vaginal colonists. These include up to six toxin-antitoxin systems and up to nine additional antitoxins lacking cognate toxins, several of which are clustered within each genome. All strains encode bacteriocidal toxins, including two lysozyme-like toxins produced uniquely by strain 409-05. Interestingly, the BV isolates encode numerous proteins not found in strain 409-05 that likely increase their pathogenic potential. These include enzymes enabling mucin degradation, a trait previously described to strongly correlate with BV, although commonly attributed to non-G. vaginalis species.
CONCLUSIONS: Collectively, our results indicate that all three strains are able to thrive in vaginal environments, and therein the BV isolates are capable of occupying a niche that is unique from 409-05. Each strain has significant virulence potential, although genomic and metabolic differences, such as the ability to degrade mucin, indicate that the detection of G. vaginalis in the vaginal tract provides only partial information on the physiological potential of the organism.
ESTHER : Yeoman_2010_PLoS.One_5_e12411
PubMedSearch : Yeoman_2010_PLoS.One_5_e12411
PubMedID: 20865041
Gene_locus related to this paper: garv4-d2rbq6 , garv4-d2rap1 , garv3-e3d9p1

Title : The glycobiome of the rumen bacterium Butyrivibrio proteoclasticus B316(T) highlights adaptation to a polysaccharide-rich environment - Kelly_2010_PLoS.One_5_e11942
Author(s) : Kelly WJ , Leahy SC , Altermann E , Yeoman CJ , Dunne JC , Kong Z , Pacheco DM , Li D , Noel SJ , Moon CD , Cookson AL , Attwood GT
Ref : PLoS ONE , 5 :e11942 , 2010
Abstract : Determining the role of rumen microbes and their enzymes in plant polysaccharide breakdown is fundamental to understanding digestion and maximising productivity in ruminant animals. Butyrivibrio proteoclasticus B316(T) is a gram-positive, butyrate-forming rumen bacterium with a key role in plant polysaccharide degradation. The 4.4 Mb genome consists of 4 replicons; a chromosome, a chromid and two megaplasmids. The chromid is the smallest reported for all bacteria, and the first identified from the phylum Firmicutes. B316 devotes a large proportion of its genome to the breakdown and reassembly of complex polysaccharides and has a highly developed glycobiome when compared to other sequenced bacteria. The secretion of a range of polysaccharide-degrading enzymes which initiate the breakdown of pectin, starch and xylan, a subtilisin family protease active against plant proteins, and diverse intracellular enzymes to break down oligosaccharides constitute the degradative capability of this organism. A prominent feature of the genome is the presence of multiple gene clusters predicted to be involved in polysaccharide biosynthesis. Metabolic reconstruction reveals the absence of an identifiable gene for enolase, a conserved enzyme of the glycolytic pathway. To our knowledge this is the first report of an organism lacking an enolase. Our analysis of the B316 genome shows how one organism can contribute to the multi-organism complex that rapidly breaks down plant material in the rumen. It can be concluded that B316, and similar organisms with broad polysaccharide-degrading capability, are well suited to being early colonizers and degraders of plant polysaccharides in the rumen environment.
ESTHER : Kelly_2010_PLoS.One_5_e11942
PubMedSearch : Kelly_2010_PLoS.One_5_e11942
PubMedID: 20689770
Gene_locus related to this paper: butpb-e0rxq6 , butpb-e0ryg8 , butpb-e0ryt2 , butpb-e0s1b3 , butpb-e0s2z7 , butpb-e0rxr0 , butpb-e0rxg9

Title : The genome sequence of the rumen methanogen Methanobrevibacter ruminantium reveals new possibilities for controlling ruminant methane emissions - Leahy_2010_PLoS.One_5_e8926
Author(s) : Leahy SC , Kelly WJ , Altermann E , Ronimus RS , Yeoman CJ , Pacheco DM , Li D , Kong Z , McTavish S , Sang C , Lambie SC , Janssen PH , Dey D , Attwood GT
Ref : PLoS ONE , 5 :e8926 , 2010
Abstract : BACKGROUND: Methane (CH(4)) is a potent greenhouse gas (GHG), having a global warming potential 21 times that of carbon dioxide (CO(2)). Methane emissions from agriculture represent around 40% of the emissions produced by human-related activities, the single largest source being enteric fermentation, mainly in ruminant livestock. Technologies to reduce these emissions are lacking. Ruminant methane is formed by the action of methanogenic archaea typified by Methanobrevibacter ruminantium, which is present in ruminants fed a wide variety of diets worldwide. To gain more insight into the lifestyle of a rumen methanogen, and to identify genes and proteins that can be targeted to reduce methane production, we have sequenced the 2.93 Mb genome of M. ruminantium M1, the first rumen methanogen genome to be completed. METHODOLOGY/PRINCIPAL FINDINGS: The M1 genome was sequenced, annotated and subjected to comparative genomic and metabolic pathway analyses. Conserved and methanogen-specific gene sets suitable as targets for vaccine development or chemogenomic-based inhibition of rumen methanogens were identified. The feasibility of using a synthetic peptide-directed vaccinology approach to target epitopes of methanogen surface proteins was demonstrated. A prophage genome was described and its lytic enzyme, endoisopeptidase PeiR, was shown to lyse M1 cells in pure culture. A predicted stimulation of M1 growth by alcohols was demonstrated and microarray analyses indicated up-regulation of methanogenesis genes during co-culture with a hydrogen (H(2)) producing rumen bacterium. We also report the discovery of non-ribosomal peptide synthetases in M. ruminantium M1, the first reported in archaeal species. CONCLUSIONS/SIGNIFICANCE: The M1 genome sequence provides new insights into the lifestyle and cellular processes of this important rumen methanogen. It also defines vaccine and chemogenomic targets for broad inhibition of rumen methanogens and represents a significant contribution to worldwide efforts to mitigate ruminant methane emissions and reduce production of anthropogenic greenhouse gases.
ESTHER : Leahy_2010_PLoS.One_5_e8926
PubMedSearch : Leahy_2010_PLoS.One_5_e8926
PubMedID: 20126622
Gene_locus related to this paper: metrm-metxa