Publications by authors named "Todd Atherly"

13 Publications

  • Page 1 of 1

Colonization with Candidate Oral Probiotics Attenuates Colonization and Virulence of .

Appl Environ Microbiol 2020 Dec 4. Epub 2020 Dec 4.

UF College of Dentistry, Department of Oral Biology, P.O. Box 100424, Gainesville, FL 32610-3003.

A collection of 113 strains from supragingival dental plaque of caries-free individuals were recently tested for direct antagonism of the dental caries pathogen , and for their capacity for arginine catabolism via the arginine deiminase system (ADS). To advance their evaluation as potential probiotics, twelve strains of commensal oral streptococci with various antagonistic and ADS potentials were assessed in a mouse model for oral (i.e., oral mucosal pellicles and saliva) and dental colonization under four diets (healthy or high-sucrose, with or without prebiotic arginine). Colonization by autochthonous bacteria was also monitored. One strain failed to colonize, whereas oral colonization by the other eleven strains varied by 3 log units. Dental colonization was high for five strains regardless of diet, six strains increased colonization with at least one high-sucrose diet, and added dietary arginine decreased dental colonization of two strains. sp. A12 (high ADS activity and antagonism) and two engineered mutants lacking the ADS (Δ) or pyruvate oxidase-mediated HO production (Δ) were tested for competition against UA159. A12 wild type and Δ colonized only transiently, whereas Δ persisted, but without altering oral or dental colonization by In testing four additional candidates, BCC23 markedly attenuated oral and dental colonization, enhanced colonization of autochthonous bacteria, and decreased severity of smooth surface caries under highly cariogenic conditions. Results demonstrate the utility of the mouse model to evaluate potential probiotics, revealing little correlation between antagonism and competitiveness against Our results demonstrate testing of potential oral probiotics can be accomplished and can yield information to facilitate the ultimate design and optimization of novel anti-caries probiotics. We show human oral commensals associated with dental health are an important source of potential probiotics that may be used to colonize patients under dietary conditions of highly varying cariogenicity. Assessment of competitiveness against dental caries pathogen and impact on caries identified strains or genetic elements for further study. Results also uncovered strains that enhanced oral and dental colonization by autochthonous bacteria when challenged with , suggesting cooperative interactions for future elucidation. Distinguishing a rare strain that effectively compete with under conditions that promote caries further validates our systematic approach to more critically evaluate probiotics for use in humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AEM.02490-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7851695PMC
December 2020

Treatment With Hydrolyzed Diet Supplemented With Prebiotics and Glycosaminoglycans Alters Lipid Metabolism in Canine Inflammatory Bowel Disease.

Front Vet Sci 2020 30;7:451. Epub 2020 Jul 30.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.

Canine inflammatory bowel disease (IBD) is a chronic, immunologically mediated intestinal disorder, resulting from the complex interaction of genetic, environmental and immune factors. Hydrolyzed diets are used in dogs with food-responsive diarrhea (FRD) to reduce adverse responses to immunostimulatory proteins. Prebiotics (PRBs) and glycosaminoglycans (GAGs) have previously been demonstrated to show anti-inflammatory activity in the intestinal mucosa. Notably, hydrolyzed diets combined with the administration of PRBs and GAGs offer a promising approach for the treatment of canine IBD. Our aim was to investigate the effects of hydrolyzed diet and GAG+PRB co-treatment on the serum metabolomic profile of IBD dogs. Dogs with IBD randomly received either hydrolyzed diet supplemented with GAGs and PRBs (treatment 1) or hydrolyzed diet alone (treatment 2) for 10 weeks. A targeted metabolomics approach using mass spectrometry was performed to quantify changes in the serum metabolome before and after treatment and between treatment 1 and 2. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), hierarchical cluster analysis (HCA) and univariate statistics were used to identify differences between the treatment groups. PCA, PLS-DA, and HCA showed a clear clustering of IBD dogs before and after hydrolyzed diet, indicating that the treatment impacted the serum metabolome. Univariate analysis revealed that most of the altered metabolites were involved in lipid metabolism. The most impacted lipid classes were components of cell membranes, including glycerophospholipids, sphingolipids, and di- and triglycerides. In addition, changes in serum metabolites after GAG+PRB co-treatment suggested a possible additional beneficial effect on the lipid metabolism in IBD dogs. In conclusion, the present study showed a significant increase in metabolites that protect gut cell membrane integrity in response to hydrolyzed diet alone or in combination with GAG+PRB co-treatment. Administration of such treatment over 70 days improved selected serum biomarkers of canine IBD, possibly indicating improved intestinal membrane integrity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fvets.2020.00451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7406657PMC
July 2020

Recapitulation of the accessible interface of biopsy-derived canine intestinal organoids to study epithelial-luminal interactions.

PLoS One 2020 17;15(4):e0231423. Epub 2020 Apr 17.

Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America.

Recent advances in canine intestinal organoids have expanded the option for building a better in vitro model to investigate translational science of intestinal physiology and pathology between humans and animals. However, the three-dimensional geometry and the enclosed lumen of canine intestinal organoids considerably hinder the access to the apical side of epithelium for investigating the nutrient and drug absorption, host-microbiome crosstalk, and pharmaceutical toxicity testing. Thus, the creation of a polarized epithelial interface accessible from apical or basolateral side is critical. Here, we demonstrated the generation of an intestinal epithelial monolayer using canine biopsy-derived colonic organoids (colonoids). We optimized the culture condition to form an intact monolayer of the canine colonic epithelium on a nanoporous membrane insert using the canine colonoids over 14 days. Transmission and scanning electron microscopy revealed a physiological brush border interface covered by the microvilli with glycocalyx, as well as the presence of mucin granules, tight junctions, and desmosomes. The population of stem cells as well as differentiated lineage-dependent epithelial cells were verified by immunofluorescence staining and RNA in situ hybridization. The polarized expression of P-glycoprotein efflux pump was confirmed at the apical membrane. Also, the epithelial monolayer formed tight- and adherence-junctional barrier within 4 days, where the transepithelial electrical resistance and apparent permeability were inversely correlated. Hence, we verified the stable creation, maintenance, differentiation, and physiological function of a canine intestinal epithelial barrier, which can be useful for pharmaceutical and biomedical researches.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231423PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7164685PMC
July 2020

Glucocorticoid and dietary effects on mucosal microbiota in canine inflammatory bowel disease.

PLoS One 2019 30;14(12):e0226780. Epub 2019 Dec 30.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, United States of America.

The pathogenesis of canine inflammatory bowel disease (IBD) involves complex interactions between mucosal immunity and the intestinal microbiota. Glucocorticoids are commonly administered to reduce mucosal inflammation and gastrointestinal signs. The study objective was to evaluate the effects of diet and oral prednisone on the spatial distribution of mucosal bacteria in IBD dogs. Eight dogs diagnosed with IBD were treated with immunosuppressive doses of prednisone. The mucosal microbiota from endoscopic biopsies of IBD dogs and healthy controls (HC; n = 15 dogs) was evaluated by fluorescence in situ hybridization (FISH) targeting the 16S rRNA genes of total bacteria and bacterial species relevant in canine/human IBD. Apicaljunction protein (AJP) expression using immunohistochemistry investigated the effect of medical therapy on intestinal barrier integrity. All IBD dogs had a reduction in GI signs following diet and prednisone therapy compared with baseline CIBDAI scores (P < 0.05). The mucosal microbiota of HC and diseased dogs was most abundant in free and adherent mucus. Only Lactobacilli were increased (P < 0.05) in the adherent mucus of IBD dogs compared to HC. The spatial distribution of mucosal bacteria was significantly different (P < 0.05) in IBD dogs following prednisone therapy, with higher numbers of Bifidobacteria and Streptococci detected across all mucosal compartments and increased numbers of Bifidobacterium spp., Faecalibacterium spp., and Streptococcus spp. present within adherent mucus. Differences in intestinal AJPs were detected with expression of occludin increased (P < 0.05) in IBD dogs versus HC. The expressions of occludin and E-cadherin were increased but zonulin decreased (P < 0.05 for each) in IBD dogs following prednisone therapy. In conclusion, the spatial distribution of mucosal bacteria differs between IBD and HC dogs, and in response to diet and glucocorticoid administration. Medical therapy was associated with beneficial changes in microbial community structure and enhanced mucosal epithelial AJP expression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0226780PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936794PMC
April 2020

Indoleamine-pyrrole 2,3-dioxygenase-1 (IDO-1) mRNA is over-expressed in the duodenal mucosa and is negatively correlated with serum tryptophan concentrations in dogs with protein-losing enteropathy.

PLoS One 2019 10;14(6):e0218218. Epub 2019 Jun 10.

College of Veterinary Medicine, Iowa State University, Ames, IA, United States of America.

Introduction: Dogs with protein-losing enteropathy (PLE) have decreased serum tryptophan concentrations, which may contribute to disease pathogenesis. Indoleamine-pyrrole 2,3-dioxygenase-1 (IDO-1) expression is associated with low serum tryptophan concentrations and is increased in the gastrointestinal tract of humans with inflammatory bowel disease (IBD). Therefore, the objective of our study was to determine if the mRNA expression of IDO-1 is increased in the duodenal mucosa of dogs with PLE as compared to dogs with chronic enteropathy (CE) and healthy dogs, and whether this expression is correlated with changes in serum tryptophan concentration.

Methods: Our study was a retrospective study using archived paraffin-embedded duodenal biopsy specimens from 8 healthy Beagle dogs from the Iowa State University Canine Service Colony and 18 and 6 client-owned dogs diagnosed with CE and PLE, respectively at the Bristol Veterinary School. A novel RNA in situ hybridization (ISH) technology, RNAscope, was used to identify IDO-1 mRNA mucosal expression in duodenal tissues. An IDO-1 specific probe was hybridized onto 10 duodenal biopsy sections from each dog whereby RNAscope signal (mRNA expression) was quantified by a single operator using light microscopy.

Results: Dogs with PLE had significantly higher mRNA expression of IDO-1 in the duodenal mucosa compared to healthy dogs (mucosal percentage IDO-1 positive: P = 0.0093, (mean ± S.D) control: 19.36 ± 7.08, PLE: 34.12 ± 5.98, average fold difference: 1.76 and mucosal IDO-1 H-score: P = 0.0356, (mean ± S.D) control: 45.26 ± 19.33, PLE: 84.37 ± 19.86, average fold difference: 1.86). The duodenal mucosal mRNA expression of IDO-1 was negatively correlated with serum tryptophan concentrations in dogs with PLE (mucosal IDO-1 H-score: Spearman's rank correlation coefficient = -0.94, P = 0.0048).

Conclusions: In conclusion, our study suggests that decreased serum tryptophan concentrations in dogs with PLE is associated with increased intestinal IDO-1 expression. Further studies are needed to determine potential inflammatory pathways responsible for increased expression of IDO-1 in the intestinal tract of dogs with PLE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0218218PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6557522PMC
February 2020

Interleukin-13 and interleukin-33 mRNA are underexpressed in the duodenal mucosa of German Shepherd dogs with chronic enteropathy.

J Vet Intern Med 2019 Jul 6;33(4):1660-1668. Epub 2019 Jun 6.

College of Veterinary Medicine, Iowa State University, Ames, Iowa.

Background: A recent genome-wide association study in German Shepherd dogs (GSDs) with chronic enteropathy (CE) has identified polymorphisms in the Th2 cytokine genes.

Hypothesis/objective: To determine if the expression of the Th2 cytokines, interleukin-13 (IL-13) and interleukin-33 (IL-33), is altered in the duodenal mucosa of GSDs with CE compared to non-GSDs with CE and healthy dogs.

Animals: Twenty client-owned dogs diagnosed with CE (10 GSDs and 10 non-GSDs) at the Bristol Veterinary School and 8 healthy Beagle dogs from the Iowa State University Service Colony.

Methods: Retrospective study using archived paraffin-embedded duodenal biopsy samples. A novel RNA in situ hybridization technology (RNAscope) was used to hybridize IL-13 and IL-33 mRNA probes onto at least 10 sections from duodenal biopsy samples for each dog. RNAscope signals were visualized using a microscope and semi-quantitative assessment was performed by a single operator.

Results: Based on duodenal villus, subvillus, epithelial, and lamina propria average expression scores, GSDs with CE had significantly lower IL-13 and IL-33 mRNA expression compared to non-GSDs with CE (IL-13, P < .04; IL-33, P < .02) and healthy Beagle dogs (IL-13, P < .02; IL-33, P < .004).

Conclusions And Clinical Importance: Similar to human patients with ulcerative colitis, a subtype of human inflammatory bowel disease, these data indicate that Th2 cytokines may be involved in the pathogenesis of CE in GSDs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jvim.15544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6639532PMC
July 2019

Derivation of adult canine intestinal organoids for translational research in gastroenterology.

BMC Biol 2019 04 11;17(1):33. Epub 2019 Apr 11.

Departments of Veterinary Clinical Sciences, Iowa State University, Ames, IA, USA.

Background: Large animal models, such as the dog, are increasingly being used for studying diseases including gastrointestinal (GI) disorders. Dogs share similar environmental, genomic, anatomical, and intestinal physiologic features with humans. To bridge the gap between commonly used animal models, such as rodents, and humans, and expand the translational potential of the dog model, we developed a three-dimensional (3D) canine GI organoid (enteroid and colonoid) system. Organoids have recently gained interest in translational research as this model system better recapitulates the physiological and molecular features of the tissue environment in comparison with two-dimensional cultures.

Results: Organoids were derived from tissue of more than 40 healthy dogs and dogs with GI conditions, including inflammatory bowel disease (IBD) and intestinal carcinomas. Adult intestinal stem cells (ISC) were isolated from whole jejunal tissue as well as endoscopically obtained duodenal, ileal, and colonic biopsy samples using an optimized culture protocol. Intestinal organoids were comprehensively characterized using histology, immunohistochemistry, RNA in situ hybridization, and transmission electron microscopy, to determine the extent to which they recapitulated the in vivo tissue characteristics. Physiological relevance of the enteroid system was defined using functional assays such as optical metabolic imaging (OMI), the cystic fibrosis transmembrane conductance regulator (CFTR) function assay, and Exosome-Like Vesicles (EV) uptake assay, as a basis for wider applications of this technology in basic, preclinical and translational GI research. We have furthermore created a collection of cryopreserved organoids to facilitate future research.

Conclusions: We establish the canine GI organoid systems as a model to study naturally occurring intestinal diseases in dogs and humans, and that can be used for toxicology studies, for analysis of host-pathogen interactions, and for other translational applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12915-019-0652-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460554PMC
April 2019

Randomized, controlled trial evaluating the effect of multi-strain probiotic on the mucosal microbiota in canine idiopathic inflammatory bowel disease.

Gut Microbes 2017 09 5;8(5):451-466. Epub 2017 Jul 5.

a Department of Veterinary Clinical Sciences, College of Veterinary Medicine , Iowa State University , Ames , Iowa , USA.

The intestinal microbiota is increasingly linked to the pathogenesis of idiopathic inflammatory bowel disease (IBD) in dogs. While studies have reported alterations in fecal (luminal) microbial populations, only limited information is available about the mucosal microbiota of IBD dogs at diagnosis and following medical therapy. Our aim was to characterize the mucosal microbiota and determine the clinical, microbiological, and mucosal homeostatic effects of probiotic treatment in dogs with IBD. Thirty four IBD dogs were randomized to receive standard therapy (ST = diet + prednisone) with or without probiotic. Tissue sections from endoscopic biopsies were evaluated by fluorescence in situ hybridization (FISH) on a quantifiable basis. Disease activity and changes in mucosal microbiota and tight junction protein (TJP) expression were assessed before and after 8 weeks of IBD therapy. ST and ST/probiotic therapy modulated the number of mucosal bacteria of IBD dogs in a similar fashion. Both treatments increased the numbers of total bacteria and individual species residing within adherent mucus, with ST therapy increasing Bifidobacterium spp. and ST/probiotic therapy increasing Lactobacillus spp (P < 0.05 for both), respectively. Both treatments were associated with rapid clinical remission but not improvement in histopathologic inflammation. Probiotic therapy was associated with upregulated (P < 0.05) expression of TJPs E-cadherin, occludin, and zonulin versus ST. The probiotic effect on mucosal bacteria is similar to that of IBD dogs receiving ST. IBD dogs fed probiotic had increased TJP expression suggesting that probiotic may have beneficial effects on mucosal homeostasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/19490976.2017.1334754DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5628651PMC
September 2017

Helicobacter bilis Infection Alters Mucosal Bacteria and Modulates Colitis Development in Defined Microbiota Mice.

Inflamm Bowel Dis 2016 11;22(11):2571-2581

*USDA-ARS, Ames, Iowa; †Department of Genetics, Development, and Cell Biology, College of Liberal Arts and Sciences, Iowa State University, Ames, Iowa; and Departments of ‡Veterinary Diagnostic and Production Animal Medicine, §Veterinary Pathology, ‖Veterinary Microbiology and Preventive Medicine, and ¶Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa.

Background: Helicobacter bilis infection of C3H/HeN mice harboring the altered Schaedler flora (ASF) triggers progressive immune responsiveness and the development of colitis. We sought to investigate temporal alterations in community structure of a defined (ASF-colonized) microbiota in normal and inflamed murine intestines and to correlate microbiota changes to histopathologic lesions.

Methods: The colonic mucosal microbiota of healthy mice and ASF mice colonized with H. bilis for 3, 6, or 12 weeks were investigated by fluorescence in situ hybridization targeting the 16S ribosomal RNA genes of total bacteria, group-specific organisms, and individual ASF bacterial species. Microbial profiling of ASF and H. bilis abundance was performed on cecal contents.

Results: Helicobacter bilis-colonized mice developed colitis associated with temporal changes in composition and spatial distribution of the mucosal microbiota. The number of total bacteria, ASF519, and helicobacter-positive bacteria were increased (P < 0.05), whereas ASF360/361-positive bacteria were decreased (P < 0.05) versus controls. Adherent biofilms in colitic mice were most often (P < 0.05) composed of total bacteria, ASF457, and H. bilis. Total numbers of ASF519 and H. bilis bacteria were positively correlated (P = 0.03, r = 0.39 and P < 0.0001, r = 0.73), and total numbers of ASF360/361 bacteria were negatively correlated (P = 0.003, r = -0.53) to histopathologic score. Differences in cecal abundance of ASF members were not observed.

Conclusions: Altered community structure with murine colitis is characterized by distinct ASF bacteria that interact with the colonic mucosa, by formation of an isolating interlaced layer, by attachment, or by invasion, and this interaction is differentially expressed over time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MIB.0000000000000944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123692PMC
November 2016

Alterations of the Ileal and Colonic Mucosal Microbiota in Canine Chronic Enteropathies.

PLoS One 2016 3;11(2):e0147321. Epub 2016 Feb 3.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, United States of America.

Background: The intestinal microbiota is increasingly linked to the pathogenesis of chronic enteropathies (CE) in dogs. While imbalances in duodenal and fecal microbial communities have been associated with mucosal inflammation, relatively little is known about alterations in mucosal bacteria seen with CE involving the ileum and colon.

Aim: To investigate the composition and spatial organization of mucosal microbiota in dogs with CE and controls.

Methods: Tissue sections from endoscopic biopsies of the ileum and colon from 19 dogs with inflammatory bowel disease (IBD), 6 dogs with granulomatous colitis (GC), 12 dogs with intestinal neoplasia, and 15 controls were studied by fluorescence in situ hybridization (FISH) on a quantifiable basis.

Results: The ileal and colonic mucosa of healthy dogs and dogs with CE is predominantly colonized by bacteria localized to free and adherent mucus compartments. CE dogs harbored more (P < 0.05) mucosal bacteria belonging to the Clostridium-coccoides/Eubacterium rectale group, Bacteroides, Enterobacteriaceae, and Escherichia coli versus controls. Within the CE group, IBD dogs had increased (P < 0.05) Enterobacteriaceae and E. coli bacteria attached onto surface epithelia or invading within the intestinal mucosa. Bacterial invasion with E. coli was observed in the ileal and colonic mucosa of dogs with GC (P < 0.05). Dogs with intestinal neoplasia had increased (P < 0.05) adherent (total bacteria, Enterobacteriaceae, E. coli) and invasive (Enterobacteriaceae, E. coli, and Bacteroides) bacteria in biopsy specimens. Increased numbers of total bacteria adherent to the colonic mucosa were associated with clinical disease severity in IBD dogs (P < 0.05).

Conclusion: Pathogenic events in canine CE are associated with different populations of the ileal and colonic mucosal microbiota.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147321PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740465PMC
July 2016

Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism.

Nature 2015 Jan;517(7533):165-169

Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA.

Yeasts, which have been a component of the human diet for at least 7,000 years, possess an elaborate cell wall α-mannan. The influence of yeast mannan on the ecology of the human microbiota is unknown. Here we show that yeast α-mannan is a viable food source for the Gram-negative bacterium Bacteroides thetaiotaomicron, a dominant member of the microbiota. Detailed biochemical analysis and targeted gene disruption studies support a model whereby limited cleavage of α-mannan on the surface generates large oligosaccharides that are subsequently depolymerized to mannose by the action of periplasmic enzymes. Co-culturing studies showed that metabolism of yeast mannan by B. thetaiotaomicron presents a 'selfish' model for the catabolism of this difficult to breakdown polysaccharide. Genomic comparison with B. thetaiotaomicron in conjunction with cell culture studies show that a cohort of highly successful members of the microbiota has evolved to consume sterically-restricted yeast glycans, an adaptation that may reflect the incorporation of eukaryotic microorganisms into the human diet.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nature13995DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4978465PMC
January 2015

Bacteroides isolated from four mammalian hosts lack host-specific 16S rRNA gene phylogeny and carbon and nitrogen utilization patterns.

Microbiologyopen 2014 Apr 17;3(2):225-38. Epub 2014 Feb 17.

USDA - Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, Iowa, 50010-3120.

One-hundred-and-three isolates of Bacteroides ovatus, B. thetaiotaomicron, and B. xylanisolvens were recovered from cow, goat, human, and pig fecal enrichments with cellulose or xylan/pectin. Isolates were compared using 16S rRNA gene sequencing, repetitive sequence-based polymerase chain reaction (rep-PCR), and phenotypic microarrays. Analysis of 16S rRNA gene sequences revealed high sequence identity in these Bacteroides; with distinct phylogenetic groupings by bacterial species but not host origin. Phenotypic microarray analysis demonstrated these Bacteroides shared the ability to utilize many of the same carbon substrates, without differences due to species or host origin, indicative of their broad carbohydrate fermentation abilities. Limited nitrogen substrates were utilized; in addition to ammonia, guanine, and xanthine, purine derivatives were utilized by most isolates followed by a few amino sugars. Only rep-PCR analysis demonstrated host-specific patterns, indicating that genomic changes due to coevolution with host did not occur by mutation in the 16S rRNA gene or by a gain or loss of carbohydrate utilization genes within these Bacteroides. This is the first report to indicate that host-associated genomic differences are outside of 16S rRNA gene and carbohydrate utilization genes and suggest conservation of specific bacterial species with the same functionality across mammalian hosts for this Bacteroidetes clade.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mbo3.159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3996570PMC
April 2014
-->