The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Michael J Wannemuehler - One of the best experts on this subject based on the ideXlab platform.
-
Mouse Genetic Background Affects Transfer of an Antibiotic Resistance Plasmid in the Gastrointestinal Tract.
mSphere, 2020Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Graham A. J. Redweik, Melha MellataAbstract:ABSTRACT Dissemination of antibiotic resistance (AR) genes, often on plasmids, leads to antibiotic-resistant bacterial infections, which is a major problem for animal and public health. Bacterial conjugation is the primary route of AR gene transfer in the mammalian gastrointestinal tract. Significant gaps in knowledge about which gastrointestinal communities and host factors promote plasmid transfer remain. Here, we used Salmonella enterica serovar Kentucky strain CVM29188 carrying plasmid pCVM29188_146 (harboring streptomycin and tetracycline resistance genes) to assess plasmid transfer to Escherichia coli under in vitro conditions and in various mouse strains with a conventional or defined microbiota. As an initial test, the transfer of pCVM29188_146 to the E. coli strains was confirmed in vitro. Colonization resistance and, therefore, a lack of plasmid transfer were found in wild-type mice harboring a conventional microbiota. Thus, mice harboring the Altered Schaedler Flora (ASF), or ASF mice, were used to probe for host factors in the context of a defined microbiota. To assess the influence of inflammation on plasmid transfer, we compared interleukin-10 gene-deficient 129S6/SvEv ASF mice (proinflammatory environment) to wild-type 129S6/SvEv ASF mice and found no difference in transconjugant yields. In contrast, the mouse strain influenced plasmid transfer, as C3H/HeN ASF mice had significantly lower levels of transconjugants than 129S6/SvEv ASF mice. Although gastrointestinal members were identical between the ASF mouse strains, a few differences from C3H/HeN ASF mice were detected, with C3H/HeN ASF mice having significantly lower abundances of ASF members 356 (Clostridium sp.), 492 (Eubacterium plexicaudatum), and 502 (Clostridium sp.) than 129S6/SvEv ASF mice. Overall, we demonstrate that microbiota complexity and mouse genetic background influence in vivo plasmid transfer. IMPORTANCE Antibiotic resistance is a threat to public health. Many clinically relevant antibiotic resistance genes are carried on plasmids that can be transferred to other bacterial members in the gastrointestinal tract. The current study used a murine model to study the transfer of a large antibiotic resistance plasmid from a foodborne Salmonella strain to a gut commensal E. coli strain in the gastrointestinal tract. We found that different mouse genetic backgrounds and a different diversity of microbial communities influenced the level of Escherichia coli that acquired the plasmid in the gastrointestinal tract. This study suggests that the complexity of the microbial community and host genetics influence plasmid transfer from donor to recipient bacteria.
-
Altered Schaedler Flora mice a defined microbiota animal model to study the microbiota gut brain axis
Behavioural Brain Research, 2019Co-Authors: Alexandra Proctor, Gregory J Phillips, Joshua M Lyte, Mark Lyte, Michael J WannemuehlerAbstract:Abstract Despite considerable attention, the mechanisms by which the microbiota affect brain function and host behaviour via the gut-brain axis remain undefined. Identifying microbe-specific pathways that influence neuronal function and bi-directional communication between the gut microbiota and the host central nervous system is challenging due to the extreme microbial diversity in the gut of conventionally-reared mice. Herein, we describe the use of the Altered Schaedler Flora (ASF) mouse model as an alternative to conventionally-reared and germ-free animals. Colonized with only 8 bacterial species, use of ASF mice greatly simplifies the examination of microbiota-host interactions. We assessed the extent to which behaviour differed between mice with a limited consortium of bacteria compared with a complex, conventional microbiota. The elevated plus maze and open-field assays were utilized to assess murine behaviour. Histological analysis of ileum and colon was performed to evaluate intestinal morphology, and 16 s rRNA gene taxonomic profiling was performed to determine host-stress induced changes in fecal microbial communities. Behavioural and serum corticosterone differences were observed between ASF and conventionally-reared mice, while no differences were found between the intestinal morphology of these two groups. The stress of the behavioural tests induced significant changes in the ASF fecal microbial community but not in that of the conventionally-reared mice. In contrast to the conventionally-reared mice, the results indicated that the ASF mice displayed a marked anxiogenic-like behaviour. These data indicate that ASF mice represent a unique model to elucidate mechanisms governing microbiota-gut-brain communication affecting behaviour.
-
Pathogenic and non-pathogenic Escherichia coli colonization and host inflammatory response in a defined microbiota mouse model
Disease Models & Mechanisms, 2018Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Meghan Wymore Brand, Angelica Van Goor, Graham A. J. Redweik, Melha MellataAbstract:Most Escherichia coli strains in the human intestine are harmless. However, enterohemorrhagic E . coli (EHEC) is a foodborne pathogen that causes intestinal disease in humans. Conventionally-reared (CONV) mice are inconsistent models for human infections with EHEC because they are often resistant to E . coli colonization in part due to their gastrointestinal (GI) microbiota. Although antibiotic manipulation of the mouse microbiota has been a common means to overcome colonization resistance, these models have limitations. Currently, there are no licensed treatments for clinical EHEC infections, and thus new tools to study EHEC colonization need to be developed. Here, we used a defined microbiota mouse model consisting of the Altered Schaedler Flora (ASF) to characterize intestinal colonization and compare host responses following colonization with EHEC strain 278F2 or non-pathogenic E . coli strain MG1655. Significantly higher ( P P E. coli MG1655 colonized C3H/HeN ASF mice. In addition, EHEC 278F2 differentially modulated inflammatory-associated genes in colonic tissue of C3H/HeN ASF mice compared to E. coli MG1655 colonized mice. This approach allowed for prolonged colonization of the murine GI tract by pathogenic and non-pathogenic E . coli strains and for evaluation of host inflammatory processes. Overall, this system can be used as a powerful tool for future studies to assess therapeutics, microbe-microbe interactions, and strategies for preventing EHEC infections.
-
Helicobacter bilis Infection Alters Mucosal Bacteria and Modulates Colitis Development in Defined Microbiota Mice
Inflammatory Bowel Diseases, 2016Co-Authors: Todd Atherly, Michael J Wannemuehler, Gregory J Phillips, Meghan Wymore Brand, Alexandra Proctor, Curtis Mosher, Chong Wang, Jesse M. Hostetter, Albert E JergensAbstract: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 in
-
Attenuation of Colitis by Serum-Derived Bovine Immunoglobulin/Protein Isolate in a Defined Microbiota Mouse Model
Digestive Diseases and Sciences, 2015Co-Authors: Abigail L. Henderson, Michael J Wannemuehler, Meghan Wymore Brand, Ross J. Darling, Kenneth J. Maas, Christopher J. Detzel, Jesse Hostetter, Eric M. WeaverAbstract:Background The pathogenesis of inflammatory bowel disease (IBD) is complex and multifaceted including genetic predisposition, environmental components, microbial dysbiosis, and inappropriate immune activation to microbial components. Pathogenic bacterial provocateurs like adherent and invasive E. coli have been reported to increase susceptibility to Crohn’s disease. Serum-derived bovine immunoglobulin/protein isolate (SBI) is comprised primarily of immunoglobulins (Igs) that bind to conserved microbial components and neutralize exotoxins. Aim To demonstrate that oral administration of SBI may modulate mucosal inflammation following colonization with E. coli , LF82, and exposure to dextran sodium sulfate (DSS). Methods Defined microbiota mice harboring the Altered Schaedler Flora (ASF) were administered SBI or hydrolyzed collagen twice daily starting 7 days prior to challenge with E. coli LF82 and continuing for the remainder of the experiment. Mice were treated with DSS for 7 days and then evaluated for evidence of local and peripheral inflammation. Results Igs within SBI bound multiple antigens from all eight members of the ASF and E. coli LF82 by western blot analysis. Multiple parameters of LF82/DSS-induced colitis were reduced following administration of SBI, including histological lesion scores, secretion of cytokines and chemokines from cecal biopsies, intestinal fatty acid binding protein (I-FABP) and serum amyloid A from plasma. Conclusions Oral administration of SBI attenuated clinical signs of LF82/DSS-induced colitis in mice. The data are consistent with the hypothesis that SBI immunoglobulin binding of bacterial antigens in the intestinal lumen may inhibit the inflammatory cascades that contribute to IBD, thus attenuating DSS-induced colitis.
David B Schauer - One of the best experts on this subject based on the ideXlab platform.
-
colonization dynamics of Altered Schaedler Flora is influenced by gender aging and helicobacter hepaticus infection in the intestines of swiss webster mice
Applied and Environmental Microbiology, 2006Co-Authors: Zhongming Ge, Yang Feng, Nancy S Taylor, Masahiro Ohtani, Martin F Polz, David B SchauerAbstract:The distribution and colonization levels of the Altered Schaedler Flora (ASF) in their natural hosts are poorly understood. Intestinal colonization levels of the eight ASF strains in outbred Swiss Webster mice with or without Helicobacter hepaticus infection were characterized by real-time quantitative PCR. All ASF strains were detected in the cecum and colon, but some strains displayed significant variation in colonization levels with host age, gender, and H. hepaticus infection status.
-
spatial distribution and stability of the eight microbial species of the Altered Schaedler Flora in the mouse gastrointestinal tract
Applied and Environmental Microbiology, 2004Co-Authors: Ramahi Sarmarupavtarm, Zhongming Ge, David B Schauer, Martin F PolzAbstract:The overall complexity of the microbial communities in the gastrointestinal (GI) tracts of mammals has hindered observations of dynamics and interactions of individual bacterial populations. However, such information is crucial for understanding the diverse disease-causing and protective roles that gut microbiota play in their hosts. Here, we determine the spatial distribution, interanimal variation, and persistence of bacteria in the most complex defined-Flora (gnotobiotic) model system to date, viz., mice colonized with the eight strains of the Altered Schaedler Flora (ASF). Quantitative PCR protocols based on the 16S rRNA sequence of each ASF strain were developed and optimized to specifically detect as few as 10 copies of each target. Total numbers of the ASF strains were determined in the different regions of the GI tracts of three C.B-17 SCID mice. Individual strain abundance was dependent on oxygen sensitivity, with microaerotolerant Lactobacillus murinus ASF361 present at 105 to 107 cells/g of tissue in the upper GI tract and obligate anaerobic ASF strains being predominant in the cecal and colonic Flora at 108 to 1010 cells/g of tissue. The variation between the three mice was small for most ASF strains, except for Clostridium sp. strain ASF502 and Bacteroides sp. strain ASF519 in the cecum. A comparison of the relative distribution of the ASF strains in feces and the colon indicated large differences, suggesting that fecal bacterial levels may provide a poor approximation of colonic bacterial levels. All ASF strains were detected by PCR in the feces of C57BL/6 restricted Flora mice, which had been maintained in an isolator without sterile food, water, or bedding for several generations, providing evidence for the stability of these strains in the face of potential competition by bacteria introduced into the gut.
-
phylogeny of the defined murine microbiota Altered Schaedler Flora
Applied and Environmental Microbiology, 1999Co-Authors: Floyd E Dewhirst, Chihching Chien, Bruce J Paster, Rebecca L Ericson, Roger P Orcutt, David B SchauerAbstract:The “Altered Schaedler Flora” (ASF) was developed for colonizing germfree rodents with a standardized microbiota. The purpose of this study was to identify each of the eight ASF strains by 16S rRNA sequence analysis. Three strains were previously identified asLactobacillus acidophilus (strain ASF 360),Lactobacillus salivarius (strain ASF 361), andBacteroides distasonis (strain ASF 519) based on phenotypic criteria. 16S rRNA analysis indicated that each of the strains differed from its presumptive identity. The 16S rRNA sequence of strain ASF 361 is essentially identical to the 16S rRNA sequences of the type strains of Lactobacillus murinis and Lactobacillus animalis (both isolated from mice), and all of these strains probably belong to a single species. Strain ASF 360 is a novel lactobacillus that clusters with L. acidophilus andLactobacillus lactis. Strain ASF 519 falls into an unnamed genus containing [Bacteroides] distasonis, [Bacteroides] merdae, [Bacteroides] forsythus, and CDC group DF-3. This unnamed genus is in theCytophaga-Flavobacterium-Bacteroides phylum and is most closely related to the genus Porphyromonas. The spiral-shaped strain, strain ASF 457, is in the Flexistipesphylum and exhibits sequence identity with rodent isolates of Robertson. The remaining four ASF strains, which are extremely oxygen-sensitive fusiform bacteria, group phylogenetically with the low-G+C-content gram-positive bacteria (Firmicutes,Bacillus-Clostridium group). ASF 356, ASF 492, and ASF 502 fall into Clostridium cluster XIV of Collins et al. Morphologically, ASF 492 resembles members of this cluster,Roseburia cecicola, and Eubacterium plexicaudatum. The 16S rRNA sequence of ASF 492 is identical to that of E. plexicaudatum. Since the type strain and other viable original isolates of E. plexicaudatum have been lost, strain ASF 492 is a candidate for a neotype strain. Strain ASF 500 branches deeply in the low-G+C-content gram-positive phylogenetic tree but is not closely related to any organisms whose 16S rRNA sequences are currently in the GenBank database. The 16S rRNA sequence information determined in the present study should allow rapid identification of ASF strains and should permit detailed analysis of the interactions of ASF organisms during development of intestinal disease in mice that are coinfected with a variety of pathogenic microorganisms.
Meghan Wymore Brand - One of the best experts on this subject based on the ideXlab platform.
-
Pathogenic and non-pathogenic Escherichia coli colonization and host inflammatory response in a defined microbiota mouse model
Disease Models & Mechanisms, 2018Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Meghan Wymore Brand, Angelica Van Goor, Graham A. J. Redweik, Melha MellataAbstract:Most Escherichia coli strains in the human intestine are harmless. However, enterohemorrhagic E . coli (EHEC) is a foodborne pathogen that causes intestinal disease in humans. Conventionally-reared (CONV) mice are inconsistent models for human infections with EHEC because they are often resistant to E . coli colonization in part due to their gastrointestinal (GI) microbiota. Although antibiotic manipulation of the mouse microbiota has been a common means to overcome colonization resistance, these models have limitations. Currently, there are no licensed treatments for clinical EHEC infections, and thus new tools to study EHEC colonization need to be developed. Here, we used a defined microbiota mouse model consisting of the Altered Schaedler Flora (ASF) to characterize intestinal colonization and compare host responses following colonization with EHEC strain 278F2 or non-pathogenic E . coli strain MG1655. Significantly higher ( P P E. coli MG1655 colonized C3H/HeN ASF mice. In addition, EHEC 278F2 differentially modulated inflammatory-associated genes in colonic tissue of C3H/HeN ASF mice compared to E. coli MG1655 colonized mice. This approach allowed for prolonged colonization of the murine GI tract by pathogenic and non-pathogenic E . coli strains and for evaluation of host inflammatory processes. Overall, this system can be used as a powerful tool for future studies to assess therapeutics, microbe-microbe interactions, and strategies for preventing EHEC infections.
-
Helicobacter bilis Infection Alters Mucosal Bacteria and Modulates Colitis Development in Defined Microbiota Mice
Inflammatory Bowel Diseases, 2016Co-Authors: Todd Atherly, Michael J Wannemuehler, Gregory J Phillips, Meghan Wymore Brand, Alexandra Proctor, Curtis Mosher, Chong Wang, Jesse M. Hostetter, Albert E JergensAbstract: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 in
-
Attenuation of Colitis by Serum-Derived Bovine Immunoglobulin/Protein Isolate in a Defined Microbiota Mouse Model
Digestive Diseases and Sciences, 2015Co-Authors: Abigail L. Henderson, Michael J Wannemuehler, Meghan Wymore Brand, Ross J. Darling, Kenneth J. Maas, Christopher J. Detzel, Jesse Hostetter, Eric M. WeaverAbstract:Background The pathogenesis of inflammatory bowel disease (IBD) is complex and multifaceted including genetic predisposition, environmental components, microbial dysbiosis, and inappropriate immune activation to microbial components. Pathogenic bacterial provocateurs like adherent and invasive E. coli have been reported to increase susceptibility to Crohn’s disease. Serum-derived bovine immunoglobulin/protein isolate (SBI) is comprised primarily of immunoglobulins (Igs) that bind to conserved microbial components and neutralize exotoxins. Aim To demonstrate that oral administration of SBI may modulate mucosal inflammation following colonization with E. coli , LF82, and exposure to dextran sodium sulfate (DSS). Methods Defined microbiota mice harboring the Altered Schaedler Flora (ASF) were administered SBI or hydrolyzed collagen twice daily starting 7 days prior to challenge with E. coli LF82 and continuing for the remainder of the experiment. Mice were treated with DSS for 7 days and then evaluated for evidence of local and peripheral inflammation. Results Igs within SBI bound multiple antigens from all eight members of the ASF and E. coli LF82 by western blot analysis. Multiple parameters of LF82/DSS-induced colitis were reduced following administration of SBI, including histological lesion scores, secretion of cytokines and chemokines from cecal biopsies, intestinal fatty acid binding protein (I-FABP) and serum amyloid A from plasma. Conclusions Oral administration of SBI attenuated clinical signs of LF82/DSS-induced colitis in mice. The data are consistent with the hypothesis that SBI immunoglobulin binding of bacterial antigens in the intestinal lumen may inhibit the inflammatory cascades that contribute to IBD, thus attenuating DSS-induced colitis.
-
the Altered Schaedler Flora continued applications of a defined murine microbial community
Ilar Journal, 2015Co-Authors: Meghan Wymore Brand, Michael J Wannemuehler, Gregory J Phillips, Alexandra Proctor, Annemarie C Overstreet, Albert E Jergens, Roger P OrcuttAbstract:The gastrointestinal (GI) microbiota forms a mutualistic relationship with the host through complex and dynamic interactions. Because of the complexity and interindividual variation of the GI microbiota, investigating how members of the microbiota interact with each other, as well as with the host, is daunting. The Altered Schaedler Flora (ASF) is a model community of eight microorganisms that was developed by R.P. Orcutt and has been in use since the late 1970s. The eight microorganisms composing the ASF were all derived from mice, can be cultured in vitro, and are stably passed through multiple generations (at least 15 years or more by the authors) in gnotobiotic mice continually bred in isolator facilities. With the limitations associated with conventional, mono- or biassociated, and germfree mice, use of mice colonized with a consortium of known bacteria that naturally inhabit the murine gut offers a powerful system to investigate mechanisms governing host–microbiota relationships, and how members of the GI microbiota interact with one another. The ASF community offers significant advantages to study homeostatic as well as disease-related interactions by taking advantage of a well-defined, limited community of microorganisms. For example, quantification and spatial distribution of individual members, microbial genetic manipulation, genomic-scale analysis, and identification of microorganism-specific host immune responses are all achievable using the ASF model. This review compiles highlights associated with the 37-year history of the ASF, including descriptions of its continued use in biomedical research to elucidate the complexities of host-microbiome interactions in health and disease.
-
Mo1776 Increased Severity of DSS-Induced Colitis Following Vertical Transmission of AIEC Pathobiont Associated With Altered Mucosal Homeostasis and Bacterial Community Dynamics
Gastroenterology, 2015Co-Authors: Meghan Wymore Brand, Gregory J Phillips, Alexandra Proctor, Albert E Jergens, Jesse M. Hostetter, Michael J WannemuehlerAbstract:Background:The gastrointestinalmicrobiota is inherited during birth and evolves throughout the postnatal period. Few studies have chronologically evaluated changes in the heritable structure of the microbiota following introduction of a pathobiont. LF82 is an adherent invasive E. coli (AIEC) strain that has been associated with ileal Crohn's disease. Gnotobiotic C3H/HeN:TAC mice harboring the Altered Schaedler Flora (ASF) were utilized as a model to evaluate changes in the microbiota and in the sensitivity to dextran sodium sulfate (DSS)induced colitis following colonization with LF82 by vertical transmission. We hypothesized that ASF mice colonized with LF82 by vertical transmission (F1) would be less susceptible to DSS-induced inflammation compared to ASF mice colonized with LF82 as adults (F0). Methods: Adult ASF mice were colonized with LF82 by oral gavage and bred to produce F1 mice colonized with LF82 from birth. F1 and F0 mice (i.e., colonized with LF82 at 8 weeks of age) were given 2.0 % DSS in drinking water for seven days. At necropsy, colonic tissues, serum, and mesenteric lymph nodes (MLN) were harvested to evaluate the severity of intestinal inflammation and magnitude of immunologic responses. DNA extracted from feces and cecal contents was used for HTP sequencing analysis of microbial abundance. Results: More severe macroscopic and histologic inflammation was present in the F1 + DSS mice when compared to F0 + DSS mice. The mucosal lesions in the F1 + DSS mice were characterized by marked ulceration, inflammatory cell infiltrate, glandular hyperplasia and stromal collapse. Diffuse, transmural mucosal inflammation was observed in most of the F1 + DSS mice. In severely diseased F1 + DSS mice, colitis was accompanied by elevated levels of IFNγ and IL-17 secreted from colonic explants and antigen-stimulated CD4+ T cells recovered from the MLNs. Evaluation of serum for presence of ASF-specific antibody revealed decreased antibody responses in F1 compared to F0 mice. Based on 16s rRNA gene sequence taxonomic profiling, colonization of the ASF mice with LF82 Altered the structure of the microbial community as evidenced by significant changes in the abundance of L. murinus (ASF361) and M. Schaedleri (ASF457). The abundance of LF82 was increased in the F1 compared to F0 mice and was further increased following DSS treatment. Conclusions: We demonstrated that 1) LF82 persistently colonized ASF mice and was transmissible from dam to offspring, 2) LF82 colonization Altered the dynamics of the ASF community, and 3) ASF mice colonized with LF82 from birth develop more severe DSS-induced colitis as compared to mice colonized with LF82 as a young adult. These data suggest that the age at which an individual is colonized by an AIEC pathobiont will differentially impact (i.e., predisposes) the host's susceptibility to subsequent inflammatory insults.
Roger P Orcutt - One of the best experts on this subject based on the ideXlab platform.
-
the Altered Schaedler Flora continued applications of a defined murine microbial community
Ilar Journal, 2015Co-Authors: Meghan Wymore Brand, Michael J Wannemuehler, Gregory J Phillips, Alexandra Proctor, Annemarie C Overstreet, Albert E Jergens, Roger P OrcuttAbstract:The gastrointestinal (GI) microbiota forms a mutualistic relationship with the host through complex and dynamic interactions. Because of the complexity and interindividual variation of the GI microbiota, investigating how members of the microbiota interact with each other, as well as with the host, is daunting. The Altered Schaedler Flora (ASF) is a model community of eight microorganisms that was developed by R.P. Orcutt and has been in use since the late 1970s. The eight microorganisms composing the ASF were all derived from mice, can be cultured in vitro, and are stably passed through multiple generations (at least 15 years or more by the authors) in gnotobiotic mice continually bred in isolator facilities. With the limitations associated with conventional, mono- or biassociated, and germfree mice, use of mice colonized with a consortium of known bacteria that naturally inhabit the murine gut offers a powerful system to investigate mechanisms governing host–microbiota relationships, and how members of the GI microbiota interact with one another. The ASF community offers significant advantages to study homeostatic as well as disease-related interactions by taking advantage of a well-defined, limited community of microorganisms. For example, quantification and spatial distribution of individual members, microbial genetic manipulation, genomic-scale analysis, and identification of microorganism-specific host immune responses are all achievable using the ASF model. This review compiles highlights associated with the 37-year history of the ASF, including descriptions of its continued use in biomedical research to elucidate the complexities of host-microbiome interactions in health and disease.
-
Quantitative PCR assays for mouse enteric Flora reveal strain-dependent differences in composition that are influenced by the microenvironment
Mammalian Genome, 2006Co-Authors: A. Deloris Alexander, Roger P Orcutt, Janell C. Henry, Joseph Baker, Anika C. Bissahoyo, David W. ThreadgillAbstract:The mammalian gastrointestinal (GI) tract is inhabited by over a hundred species of symbiotic bacteria. Differences among individuals in the composition of the GI Flora may contribute to variation in in vivo experimental analyses and disease susceptibility. To investigate potential interindividual differences in GI Flora composition, we developed real-time quantitative PCR-based assays for the detection of the eight members of the Altered Schaedler Flora (ASF) as representative members of different bacterial niches within the mammalian GI tract. Quantitative and reproducible strain-specific variations in the numbers of the ASF members were observed across 23 different barrier-housed inbred mouse strains, suggesting that the ASF assays can be used as sentinels for changes in GI Flora composition. A significant cage effect was also detected. Isogenic mice that cohabited at weaning, whether from the same or different litters, showed little variation in ASF profiles. Conversely, litters split among different cages at weaning showed divergence in ASF profiles after three weeks. Individual ASF profiles, once established, were highly stable over time in the absence of environmental perturbation. Furthermore, cohabitation of different inbred strains maintained most of the interstrain variation in the GI Flora, supporting a role of host genetics in determining GI Flora composition.
-
phylogeny of the defined murine microbiota Altered Schaedler Flora
Applied and Environmental Microbiology, 1999Co-Authors: Floyd E Dewhirst, Chihching Chien, Bruce J Paster, Rebecca L Ericson, Roger P Orcutt, David B SchauerAbstract:The “Altered Schaedler Flora” (ASF) was developed for colonizing germfree rodents with a standardized microbiota. The purpose of this study was to identify each of the eight ASF strains by 16S rRNA sequence analysis. Three strains were previously identified asLactobacillus acidophilus (strain ASF 360),Lactobacillus salivarius (strain ASF 361), andBacteroides distasonis (strain ASF 519) based on phenotypic criteria. 16S rRNA analysis indicated that each of the strains differed from its presumptive identity. The 16S rRNA sequence of strain ASF 361 is essentially identical to the 16S rRNA sequences of the type strains of Lactobacillus murinis and Lactobacillus animalis (both isolated from mice), and all of these strains probably belong to a single species. Strain ASF 360 is a novel lactobacillus that clusters with L. acidophilus andLactobacillus lactis. Strain ASF 519 falls into an unnamed genus containing [Bacteroides] distasonis, [Bacteroides] merdae, [Bacteroides] forsythus, and CDC group DF-3. This unnamed genus is in theCytophaga-Flavobacterium-Bacteroides phylum and is most closely related to the genus Porphyromonas. The spiral-shaped strain, strain ASF 457, is in the Flexistipesphylum and exhibits sequence identity with rodent isolates of Robertson. The remaining four ASF strains, which are extremely oxygen-sensitive fusiform bacteria, group phylogenetically with the low-G+C-content gram-positive bacteria (Firmicutes,Bacillus-Clostridium group). ASF 356, ASF 492, and ASF 502 fall into Clostridium cluster XIV of Collins et al. Morphologically, ASF 492 resembles members of this cluster,Roseburia cecicola, and Eubacterium plexicaudatum. The 16S rRNA sequence of ASF 492 is identical to that of E. plexicaudatum. Since the type strain and other viable original isolates of E. plexicaudatum have been lost, strain ASF 492 is a candidate for a neotype strain. Strain ASF 500 branches deeply in the low-G+C-content gram-positive phylogenetic tree but is not closely related to any organisms whose 16S rRNA sequences are currently in the GenBank database. The 16S rRNA sequence information determined in the present study should allow rapid identification of ASF strains and should permit detailed analysis of the interactions of ASF organisms during development of intestinal disease in mice that are coinfected with a variety of pathogenic microorganisms.
Martin F Polz - One of the best experts on this subject based on the ideXlab platform.
-
colonization dynamics of Altered Schaedler Flora is influenced by gender aging and helicobacter hepaticus infection in the intestines of swiss webster mice
Applied and Environmental Microbiology, 2006Co-Authors: Zhongming Ge, Yang Feng, Nancy S Taylor, Masahiro Ohtani, Martin F Polz, David B SchauerAbstract:The distribution and colonization levels of the Altered Schaedler Flora (ASF) in their natural hosts are poorly understood. Intestinal colonization levels of the eight ASF strains in outbred Swiss Webster mice with or without Helicobacter hepaticus infection were characterized by real-time quantitative PCR. All ASF strains were detected in the cecum and colon, but some strains displayed significant variation in colonization levels with host age, gender, and H. hepaticus infection status.
-
spatial distribution and stability of the eight microbial species of the Altered Schaedler Flora in the mouse gastrointestinal tract
Applied and Environmental Microbiology, 2004Co-Authors: Ramahi Sarmarupavtarm, Zhongming Ge, David B Schauer, Martin F PolzAbstract:The overall complexity of the microbial communities in the gastrointestinal (GI) tracts of mammals has hindered observations of dynamics and interactions of individual bacterial populations. However, such information is crucial for understanding the diverse disease-causing and protective roles that gut microbiota play in their hosts. Here, we determine the spatial distribution, interanimal variation, and persistence of bacteria in the most complex defined-Flora (gnotobiotic) model system to date, viz., mice colonized with the eight strains of the Altered Schaedler Flora (ASF). Quantitative PCR protocols based on the 16S rRNA sequence of each ASF strain were developed and optimized to specifically detect as few as 10 copies of each target. Total numbers of the ASF strains were determined in the different regions of the GI tracts of three C.B-17 SCID mice. Individual strain abundance was dependent on oxygen sensitivity, with microaerotolerant Lactobacillus murinus ASF361 present at 105 to 107 cells/g of tissue in the upper GI tract and obligate anaerobic ASF strains being predominant in the cecal and colonic Flora at 108 to 1010 cells/g of tissue. The variation between the three mice was small for most ASF strains, except for Clostridium sp. strain ASF502 and Bacteroides sp. strain ASF519 in the cecum. A comparison of the relative distribution of the ASF strains in feces and the colon indicated large differences, suggesting that fecal bacterial levels may provide a poor approximation of colonic bacterial levels. All ASF strains were detected by PCR in the feces of C57BL/6 restricted Flora mice, which had been maintained in an isolator without sterile food, water, or bedding for several generations, providing evidence for the stability of these strains in the face of potential competition by bacteria introduced into the gut.
