Gerald Tannock - Academia.edu (original) (raw)

Papers by Gerald Tannock

Research paper thumbnail of A rye bran diet, rich in plant lignans, has no influence on the composition of the gut microflora in postmenopausal women

Microbial Ecology in Health & Disease, 2005

The consumption of phytoestrogens has been related to a reduced risk of hormone-dependent cancer ... more The consumption of phytoestrogens has been related to a reduced risk of hormone-dependent cancer types as well as coronary heart diseases. Plant lignans that represent one class of phytoestrogens are found in relatively high concentrations in rye bran. When consumed, they are metabolized into mammalian lignans (enterodiol and enterolactone) by gut bacteria. In order to investigate whether an increased intake of plant lignans had an impact on the composition of the predominant bacterial community of the human gut a 2 )/6-week intervention study, with a crossover design, was conducted. Eighteen healthy postmenopausal women (age 55 Á/71 years) were recruited and randomly assigned to two groups. The intervention comprised bread products with either rye bran or an inert wheat cellulose (Vitacel † ). Faecal samples were collected before and at the end of each intervention period and analysed for their predominant bacterial species composition by a cultivationindependent approach Á/ polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The rye bran diet had no impact on the composition of gut microflora. However, the DGGE profiles demonstrated unique bacterial communities for each individual, which implied a differing efficiency among individuals to metabolize lignans.

Research paper thumbnail of Synthesis, characterisation and microbial utilisation of amorphous polysugars from lactose

Carbohydrate polymers, Jan 6, 2015

The melt polymerisations of glucose, galactose, xylose and fucose with citric acid, and mixtures ... more The melt polymerisations of glucose, galactose, xylose and fucose with citric acid, and mixtures of sugars therein are reported. Characterisation of the citric-acid catalysed reaction products indicated similar degrees of branched polymerisation but differences in the overall molecular weight of the polymers produced. The dairy by-product lactose could not be polymerised in a similar fashion but was shown to be readily hydrolysed using microwave radiation and a polymer generated from the melt condensation of the resultant glucose and galactose monosaccharides. A preliminary assessment of the bifido-bacterial utilisation of the lactose-derived polymerised products demonstrated a significantly different growth profile compared to commercially utilised galactooligosaccharides (GOS).

Research paper thumbnail of The bowel microbiota and inflammatory bowel diseases

International journal of inflammation, 2010

The human bowel contains a large and biodiverse bacterial community known as the microbiota or mi... more The human bowel contains a large and biodiverse bacterial community known as the microbiota or microbiome. It seems likely that the microbiota, fractions of the microbiota, or specific species comprising the microbiota provide the antigenic fuel that drives the chronic immune inflammation of the bowel mucosa that is characteristic of Crohn's disease and ulcerative colitis. At least twenty years of microbiological research have been expended on analysis of the composition of the bowel microbiota of inflammatory bowel disease patients in comparison to that of control subjects. Despite extensive speculations about the aetiological role of dysbiosis in inflammatory bowel diseases, knowledge that can be easily translated into effective remedies for patients has not eventuated. The causes of this failure may be due to poorly defined and executed bacteriological studies, as well as the overwhelming complexity of a biome that contains hundreds of bacterial species and trillions of bacte...

Research paper thumbnail of Identification of Lactobacillus isolates from the gastrointestinal tract, silage, and yoghurt by 16S-23S rRNA gene intergenic spacer region sequence comparisons

Applied and environmental microbiology, 1999

Lactobacillus isolates were identified by PCR amplification and sequencing of the region between ... more Lactobacillus isolates were identified by PCR amplification and sequencing of the region between the 16S and 23S rRNA genes (spacer region). The sequences obtained from the isolates were compared to those of reference strains held in GenBank. A similarity of 97.5% or greater was considered to provide identification. To check the reliability of the method, the V2-V3 region of the 16S rRNA gene was amplified and sequenced in the case of isolates whose spacer region sequences were less than 99% similar to that of a reference strain. Confirmation of identity was obtained in all instances. Spacer region sequencing provided rapid and accurate identification of Lactobacillus isolates obtained from gastrointestinal, yoghurt, and silage samples. It had an advantage over 16S V2-V3 sequence comparisons because it distinguished between isolates of Lactobacillus casei and Lactobacillus rhamnosus.

Research paper thumbnail of Altered transcription of murine genes induced in the small bowel by administration of probiotic strain Lactobacillus rhamnosus HN001

Applied and environmental microbiology, 2014

Lactobacillus rhamnosus HN001 is a probiotic strain reported to increase resistance to epithelium... more Lactobacillus rhamnosus HN001 is a probiotic strain reported to increase resistance to epithelium-adherent and -invasive intestinal pathogens in experimental animals. To increase understanding of the relationship between strain HN001 and the bowel, transcription of selected genes in the mucosa of the murine small bowel was measured. Mice previously naive to lactobacilli (Lactobacillus-free mice) were examined after daily exposure to HN001 in drinking water. Comparisons were made to results from matched Lactobacillus-free mice. Infant and adult mice were investigated to provide a temporal view of gene expression in response to exposure to HN001. Genes sgk1, angptl4, and hspa1b, associated with the apoptosis pathway, were selected for investigation by reverse transcription-quantitative PCR on the basis of a preliminary duodenal DNA microarray screen. Normalized to gapdh gene transcription, these three genes were upregulated after 6 to 10 days exposure of adult mice to HN001. Angptl4 w...

Research paper thumbnail of Carboxy-methylcellulose decreases colonic inflammation and changes bacterial flora in the Hla-B27 transgenic rat

Introduction: ~he therapeutlc options for inflammatory bowel disease (IBD) remain limited, especi... more Introduction: ~he therapeutlc options for inflammatory bowel disease (IBD) remain limited, especially tor remission prolongation knti-TNF-a antibodies such as lntltxinmb are effective in the treatment ol flares but ohen lose their ethcacy with repetitive applications, 13-Hydroxyoctadecatnen*~ acid a componem of the sungnig nettle leaf (Hox alpha, Strathmann (krrnany) reduces TNF-c~ secretion and is a known therapy m the setting of rheumatoid arthritis Aim: 1"o investigate the etlect of Hox alpha on murine colitis disease activity in difli:rent colitic mouse models Methods: C3}tIHeJBir,IL-10-/-and BALB/{ mice with DSSreduced acute and cbronic colitis were treated with 0 5mg/ml Hox alpha and compared to untreated controls Mice were clniically monitorvd and inflammation was assessed by histological scoring, analysis oi kcal/I.-113 and measurement ot mucosal cytokine production by EL/SA Probkration of lynlphocytes ot the spleen and Peyers patches was quantified by 3H-thynlidine nico~)oration. Resuhs: Hox alpha-treated mice ,aqth chronic DSS colitis as well as Hox alpha-treated ID 10-A mice displayed signihcantly reduced clniical and histologB <al signs ot colitis than untreated mice (p<0 05) Fecal IL-113, mucosal IL-113 as well as TNF-~ concentrations were signit~cantly lowe* in Hox alpha-treated chronic DSS mice as well as in ttox alpha-treated lL-10-/-mice m comparison with control rnice (p<0.05). Furthe*r~mre, 1ympbocyte prolfl~'ration postdipopolysaccharide stimulation was significantly reduced in Hox alpha-treated mice (p<0001) Conclusions: The continuous use of Hox alpha is effective in the amelioration of chronic murme colitis, an effect we attribute to a decreased Thl immune response Hox alpha thus possibly presents us with a new therapeutic option fur prolonging remission in 1BD.

Research paper thumbnail of Cholic Acid Is Accumulated Spontaneously, Driven by Membrane Delta pH, in Many Lactobacilli

Journal of Bacteriology, 2000

Many lactobacilli from various origins were found to apparently lack cholic acid extrusion activi... more Many lactobacilli from various origins were found to apparently lack cholic acid extrusion activity. Cholic acid was accumulated spontaneously, driven by the transmembrane proton gradient. Accumulation is a newly identified kind of interaction between intestinal microbes and unconjugated bile acids and is different from extrusion and modification, which have been described previously.

Research paper thumbnail of The Evolution of Host Specialization in the Vertebrate Gut Symbiont Lactobacillus reuteri

Plos Genetics, 2011

Recent research has provided mechanistic insight into the important contributions of the gut micr... more Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.

Research paper thumbnail of Responses to one or two doses of a deoxycholate subunit influenza vaccine in a primed population

Research paper thumbnail of A note on the use of a plasmid as a DNA probe in the detection of a Lactobacillus fermentum strain in porcine stomach contents

Journal of Applied Microbiology - J APPL MICROBIOL, 1992

New Zealand and ' Intestinal Microecology Consultant, Three Mile Cross, Reading, UK 4042/11/91: a... more New Zealand and ' Intestinal Microecology Consultant, Three Mile Cross, Reading, UK 4042/11/91: accepted 8 February 1992 G.W. TANNOCK, M . A . McCONNELL AND R . FULLER.1992.

Research paper thumbnail of Dietary fibres as “prebiotics”: Implications for colorectal cancer

Molecular Nutrition & Food Research, 2005

A &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;prebiotic&amp... more A &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;prebiotic&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; is a nondigestible food ingredient whose beneficial effects on the host result from the selective stimulation of growth and/or activity of members of the bacterial community that inhabits the human bowel (the gut microbiota). Although much of the prebiotic literature focuses on nondigestible oligosaccharides, such as oligofructose, most dietary fibres that are fermentable carbohydrates could be considered as prebiotics. Early studies suggested that colonic bacteria were risk factors for colon cancer. However, altering the composition or metabolic activity of the bowel microbiota through the use of dietary fibre might be important in reducing the prevalence of colorectal cancer. Mechanisms for beneficial effects of prebiotics might include changing the activity of exogenous carcinogens through modulating metabolic activation and/or detoxification, or stimulating the production of the short-chain fatty acid, butyrate. However, modern analytical techniques suggest that an important consequence of a modified bacterial community could be a change in the expression not only of a range of different bacterial genes in bowel contents, but also in the bowel mucosa of the host. Analogous with observations with probiotics, the stimulation of cytokines and modification of immune responses could be important in producing beneficial effects. Compared with transitory effects of probiotics, the prebiotic action of fermentable carbohydrates potentially provide the opportunity for sustainable modulation of activity of the gut microbiota. However, their mechanisms of action in humans are speculative, and research aimed at providing an integrated view of the gut microbiota and dietary fibre nutrition of humans needs to be developed.

Research paper thumbnail of Coliforms and enterococci isolated from the intestinal tract of conventional mice

Microbial Ecology, 1979

Coliforms and enterococci were isolated from the intestinal tract of infant (12-day-old) and adul... more Coliforms and enterococci were isolated from the intestinal tract of infant (12-day-old) and adult (6-to 8-week-old) conventional mice. Eighty coliform isolates and eighty enterococcal strains were grouped according to their ability to ferment or hydrolyze various substrates. Sixty-one of the coliform isolates were identified as Escherichia coli. The remaining 19 strains were similar to E. coli, but did not produce/3-galactosidase. The enterococci belonged to two species: Streptococcus faecium and S. faecalis. Four biotypes of S. faecium and two biotypes of S. faecalis were detected. Xylosefermenting enterococci were isolated with a higher frequency from infant mice than from adults.

Research paper thumbnail of Analysis of the large bowel microbiota of colitic mice using PCR/DGGE

Letters in Applied Microbiology, 2005

R . B I B I L O N I , M . A .

Research paper thumbnail of The bacteriology of biopsies differs between newly diagnosed, untreated, Crohn's disease and ulcerative colitis patients

Journal of Medical Microbiology, 2006

The bacterial community (microbiota) that inhabits the gut of humans appears to be an important s... more The bacterial community (microbiota) that inhabits the gut of humans appears to be an important source of antigens that drive the chronic immunological processes characteristic of Crohn's disease (CD) and ulcerative colitis (UC). Most of the members of the microbiota have not yet been cultured, but nucleic-acid-based methods of detection and enumeration can provide information about the community. This investigation used these methods to obtain information about the bacteria associated with mucosal surfaces in the gut of 20 CD and 15 UC patients. Biopsies were collected from inflamed and non-inflamed sites in the intestines of newly diagnosed, untreated patients. Biopsies were also collected from several intestinal sites of 14 healthy subjects. The bacterial collections associated with the biopsies were analysed by generating PCR/denaturing gradient gel electrophoresis (DGGE) profiles, the preparation of 16S rRNA gene clone libraries, and qualitative PCR to detect specific groups of bacteria. The total numbers of bacteria associated with the biopsies were determined by real-time quantitative PCR. DGGE profiles generated from the terminal ileum and various colonic regions were characteristic of each individual but differed between subjects. DGGE profiles and 16S rRNA gene libraries showed that the bacteria associated with inflamed and non-inflamed tissues did not differ. UC patients had more bacteria associated with biopsies than did CD patients (P<0?01). Statistical analysis of the composition of 16S rRNA gene libraries showed that the bacterial collections in UC and CD patients differed (P<0?05). Unclassified members of the phylum Bacteroidetes were more prevalent in CD than in UC patients. Therefore, the types and numbers of bacteria associated with biopsy samples were distinctly different for UC and CD patients. The observations made in this study should permit targeting of specific bacteriological abnormalities in investigations of the pathogenesis of inflammatory bowel diseases and provide targets for medical interventions.

Research paper thumbnail of Differential clustering of bowel biopsy-associated bacterial profiles of specimens collected in Mexico and Canada: what do these profiles represent?

Journal of Medical Microbiology, 2008

Research paper thumbnail of Testing probiotic strain Escherichia coli Nissle 1917 (Mutaflor) for its ability to reduce carriage of multidrug-resistant E. coli by elderly residents in long-term care facilities

Journal of Medical Microbiology, 2011

A high carriage rate of multidrug-resistant Escherichia coli (MDREC) was observed in elderly resi... more A high carriage rate of multidrug-resistant Escherichia coli (MDREC) was observed in elderly residents in long-term care facilities. A double-blinded, placebo-controlled trial was carried out to determine whether the probiotic product E. coli strain Nissle 1917 (Mutaflor) would compete with MDREC in the bowel and thereby reduce the prevalence of the multiresistant bacteria in faeces and urine. Sixty-nine patients excreting norfloxacin-resistant E. coli were randomized to probiotic or placebo groups and administered capsules twice daily. The daily dose of probiotic was 5¾10 9 -5¾10 10 bacteria. Faecal and urine samples were cultured at baseline and during and after the treatment period. A reduction in baseline carriage was not influenced by probiotic administration. The probiotic strain was detected in faecal specimens collected during the treatment period of only two out of 12 probiotic group subjects that were tested. Genotyping of norfloxacin-resistant E. coli isolates showed that 32 strains were prevalent among the patients. Thus, E. coli Nissle 1917 does not have the capacity to compete effectively with MDREC in the bowel of elderly patients. %paper no. jmm025874 charlesworth ref: jmm025874& Clinical microbiology and virology Abbreviations: ESBL, extended-spectrum b-lactamase; LTCF, long-term care facility; MDR, multidrug resistant; MDREC, MDR Escherichia coli; UPGMA, unweighted pair group method with arithmetic mean.

Research paper thumbnail of The microflora of the pig stomach and its possible relationship to ulceration of the pars oesophagea

Journal of Comparative Pathology, 1970

Research paper thumbnail of A differential effect of 2 probiotics in the prevention of eczema and atopy: A double-blind, randomized, placebo-controlled trial

Journal of Allergy and Clinical Immunology, 2008

The role of probiotics in prevention of allergic disease is still not clearly established, althou... more The role of probiotics in prevention of allergic disease is still not clearly established, although early reports suggested Lactobacillus GG halved the risk of eczema at 2 years. To determine whether probiotic supplementation in early life could prevent development of eczema and atopy at 2 years. Double-blind, randomized placebo-controlled trial of infants at risk of allergic disease. Pregnant women were randomized to take Lactobacillus rhamnosus HN001 (L rhamnosus), Bifidobacterium animalis subsp lactis strain HN019 or placebo daily from 35 weeks gestation until 6 months if breast-feeding, and their infants were randomized to receive the same treatment from birth to 2 years (n = 474). The infant&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s cumulative prevalence of eczema and point prevalence of atopy, using skin prick tests to common allergens, was assessed at 2 years. Infants receiving L rhamnosus had a significantly (P = .01) reduced risk of eczema (hazard ratio [HR], 0.51; 95% CI, 0.30-0.85) compared with placebo, but this was not the case for B animalis subsp lactis (HR, 0.90; 95% CI, 0.58-1.41). There was no significant effect of L rhamnosus (HR, 0.74; 95% CI, 0.46-1.18) or B animalis subsp lactis (HR, 0.82; 95% CI, 0.52-1.28) on atopy. L rhamnosus (71.5%) was more likely than B animalis subsp lactis (22.6%) to be present in the feces at 3 months, although detection rates were similar by 24 months. We found that supplementation with L rhamnosus, but not B animalis subsp lactis, substantially reduced the cumulative prevalence of eczema, but not atopy, by 2 years. Understanding how Lactobacilli act to prevent eczema requires further investigation.

Research paper thumbnail of Commentary: Remembrance of microbes past

International Journal of Epidemiology, 2004

Research paper thumbnail of Bifidobacterium animalis causes extensive duodenitis and mild colonic inflammation in monoassociated interleukin-10-deficient mice

Inflammatory Bowel Diseases, 2009

Background-We recently showed that Bifidobacterium animalis is more prevalent within the colons o... more Background-We recently showed that Bifidobacterium animalis is more prevalent within the colons of IL-10 deficient (−/−) mice than in wild type (WT) animals colonized with the same specific pathogen free (SPF) fecal contents. Here we tested the ability of this organism to cause T cell-mediated intestinal inflammation by introducing it into germ-free (GF) IL-10−/− mice.

Research paper thumbnail of A rye bran diet, rich in plant lignans, has no influence on the composition of the gut microflora in postmenopausal women

Microbial Ecology in Health & Disease, 2005

The consumption of phytoestrogens has been related to a reduced risk of hormone-dependent cancer ... more The consumption of phytoestrogens has been related to a reduced risk of hormone-dependent cancer types as well as coronary heart diseases. Plant lignans that represent one class of phytoestrogens are found in relatively high concentrations in rye bran. When consumed, they are metabolized into mammalian lignans (enterodiol and enterolactone) by gut bacteria. In order to investigate whether an increased intake of plant lignans had an impact on the composition of the predominant bacterial community of the human gut a 2 )/6-week intervention study, with a crossover design, was conducted. Eighteen healthy postmenopausal women (age 55 Á/71 years) were recruited and randomly assigned to two groups. The intervention comprised bread products with either rye bran or an inert wheat cellulose (Vitacel † ). Faecal samples were collected before and at the end of each intervention period and analysed for their predominant bacterial species composition by a cultivationindependent approach Á/ polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The rye bran diet had no impact on the composition of gut microflora. However, the DGGE profiles demonstrated unique bacterial communities for each individual, which implied a differing efficiency among individuals to metabolize lignans.

Research paper thumbnail of Synthesis, characterisation and microbial utilisation of amorphous polysugars from lactose

Carbohydrate polymers, Jan 6, 2015

The melt polymerisations of glucose, galactose, xylose and fucose with citric acid, and mixtures ... more The melt polymerisations of glucose, galactose, xylose and fucose with citric acid, and mixtures of sugars therein are reported. Characterisation of the citric-acid catalysed reaction products indicated similar degrees of branched polymerisation but differences in the overall molecular weight of the polymers produced. The dairy by-product lactose could not be polymerised in a similar fashion but was shown to be readily hydrolysed using microwave radiation and a polymer generated from the melt condensation of the resultant glucose and galactose monosaccharides. A preliminary assessment of the bifido-bacterial utilisation of the lactose-derived polymerised products demonstrated a significantly different growth profile compared to commercially utilised galactooligosaccharides (GOS).

Research paper thumbnail of The bowel microbiota and inflammatory bowel diseases

International journal of inflammation, 2010

The human bowel contains a large and biodiverse bacterial community known as the microbiota or mi... more The human bowel contains a large and biodiverse bacterial community known as the microbiota or microbiome. It seems likely that the microbiota, fractions of the microbiota, or specific species comprising the microbiota provide the antigenic fuel that drives the chronic immune inflammation of the bowel mucosa that is characteristic of Crohn's disease and ulcerative colitis. At least twenty years of microbiological research have been expended on analysis of the composition of the bowel microbiota of inflammatory bowel disease patients in comparison to that of control subjects. Despite extensive speculations about the aetiological role of dysbiosis in inflammatory bowel diseases, knowledge that can be easily translated into effective remedies for patients has not eventuated. The causes of this failure may be due to poorly defined and executed bacteriological studies, as well as the overwhelming complexity of a biome that contains hundreds of bacterial species and trillions of bacte...

Research paper thumbnail of Identification of Lactobacillus isolates from the gastrointestinal tract, silage, and yoghurt by 16S-23S rRNA gene intergenic spacer region sequence comparisons

Applied and environmental microbiology, 1999

Lactobacillus isolates were identified by PCR amplification and sequencing of the region between ... more Lactobacillus isolates were identified by PCR amplification and sequencing of the region between the 16S and 23S rRNA genes (spacer region). The sequences obtained from the isolates were compared to those of reference strains held in GenBank. A similarity of 97.5% or greater was considered to provide identification. To check the reliability of the method, the V2-V3 region of the 16S rRNA gene was amplified and sequenced in the case of isolates whose spacer region sequences were less than 99% similar to that of a reference strain. Confirmation of identity was obtained in all instances. Spacer region sequencing provided rapid and accurate identification of Lactobacillus isolates obtained from gastrointestinal, yoghurt, and silage samples. It had an advantage over 16S V2-V3 sequence comparisons because it distinguished between isolates of Lactobacillus casei and Lactobacillus rhamnosus.

Research paper thumbnail of Altered transcription of murine genes induced in the small bowel by administration of probiotic strain Lactobacillus rhamnosus HN001

Applied and environmental microbiology, 2014

Lactobacillus rhamnosus HN001 is a probiotic strain reported to increase resistance to epithelium... more Lactobacillus rhamnosus HN001 is a probiotic strain reported to increase resistance to epithelium-adherent and -invasive intestinal pathogens in experimental animals. To increase understanding of the relationship between strain HN001 and the bowel, transcription of selected genes in the mucosa of the murine small bowel was measured. Mice previously naive to lactobacilli (Lactobacillus-free mice) were examined after daily exposure to HN001 in drinking water. Comparisons were made to results from matched Lactobacillus-free mice. Infant and adult mice were investigated to provide a temporal view of gene expression in response to exposure to HN001. Genes sgk1, angptl4, and hspa1b, associated with the apoptosis pathway, were selected for investigation by reverse transcription-quantitative PCR on the basis of a preliminary duodenal DNA microarray screen. Normalized to gapdh gene transcription, these three genes were upregulated after 6 to 10 days exposure of adult mice to HN001. Angptl4 w...

Research paper thumbnail of Carboxy-methylcellulose decreases colonic inflammation and changes bacterial flora in the Hla-B27 transgenic rat

Introduction: ~he therapeutlc options for inflammatory bowel disease (IBD) remain limited, especi... more Introduction: ~he therapeutlc options for inflammatory bowel disease (IBD) remain limited, especially tor remission prolongation knti-TNF-a antibodies such as lntltxinmb are effective in the treatment ol flares but ohen lose their ethcacy with repetitive applications, 13-Hydroxyoctadecatnen*~ acid a componem of the sungnig nettle leaf (Hox alpha, Strathmann (krrnany) reduces TNF-c~ secretion and is a known therapy m the setting of rheumatoid arthritis Aim: 1"o investigate the etlect of Hox alpha on murine colitis disease activity in difli:rent colitic mouse models Methods: C3}tIHeJBir,IL-10-/-and BALB/{ mice with DSSreduced acute and cbronic colitis were treated with 0 5mg/ml Hox alpha and compared to untreated controls Mice were clniically monitorvd and inflammation was assessed by histological scoring, analysis oi kcal/I.-113 and measurement ot mucosal cytokine production by EL/SA Probkration of lynlphocytes ot the spleen and Peyers patches was quantified by 3H-thynlidine nico~)oration. Resuhs: Hox alpha-treated mice ,aqth chronic DSS colitis as well as Hox alpha-treated ID 10-A mice displayed signihcantly reduced clniical and histologB <al signs ot colitis than untreated mice (p<0 05) Fecal IL-113, mucosal IL-113 as well as TNF-~ concentrations were signit~cantly lowe* in Hox alpha-treated chronic DSS mice as well as in ttox alpha-treated lL-10-/-mice m comparison with control rnice (p<0.05). Furthe*r~mre, 1ympbocyte prolfl~'ration postdipopolysaccharide stimulation was significantly reduced in Hox alpha-treated mice (p<0001) Conclusions: The continuous use of Hox alpha is effective in the amelioration of chronic murme colitis, an effect we attribute to a decreased Thl immune response Hox alpha thus possibly presents us with a new therapeutic option fur prolonging remission in 1BD.

Research paper thumbnail of Cholic Acid Is Accumulated Spontaneously, Driven by Membrane Delta pH, in Many Lactobacilli

Journal of Bacteriology, 2000

Many lactobacilli from various origins were found to apparently lack cholic acid extrusion activi... more Many lactobacilli from various origins were found to apparently lack cholic acid extrusion activity. Cholic acid was accumulated spontaneously, driven by the transmembrane proton gradient. Accumulation is a newly identified kind of interaction between intestinal microbes and unconjugated bile acids and is different from extrusion and modification, which have been described previously.

Research paper thumbnail of The Evolution of Host Specialization in the Vertebrate Gut Symbiont Lactobacillus reuteri

Plos Genetics, 2011

Recent research has provided mechanistic insight into the important contributions of the gut micr... more Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.

Research paper thumbnail of Responses to one or two doses of a deoxycholate subunit influenza vaccine in a primed population

Research paper thumbnail of A note on the use of a plasmid as a DNA probe in the detection of a Lactobacillus fermentum strain in porcine stomach contents

Journal of Applied Microbiology - J APPL MICROBIOL, 1992

New Zealand and ' Intestinal Microecology Consultant, Three Mile Cross, Reading, UK 4042/11/91: a... more New Zealand and ' Intestinal Microecology Consultant, Three Mile Cross, Reading, UK 4042/11/91: accepted 8 February 1992 G.W. TANNOCK, M . A . McCONNELL AND R . FULLER.1992.

Research paper thumbnail of Dietary fibres as “prebiotics”: Implications for colorectal cancer

Molecular Nutrition & Food Research, 2005

A &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;prebiotic&amp... more A &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;prebiotic&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; is a nondigestible food ingredient whose beneficial effects on the host result from the selective stimulation of growth and/or activity of members of the bacterial community that inhabits the human bowel (the gut microbiota). Although much of the prebiotic literature focuses on nondigestible oligosaccharides, such as oligofructose, most dietary fibres that are fermentable carbohydrates could be considered as prebiotics. Early studies suggested that colonic bacteria were risk factors for colon cancer. However, altering the composition or metabolic activity of the bowel microbiota through the use of dietary fibre might be important in reducing the prevalence of colorectal cancer. Mechanisms for beneficial effects of prebiotics might include changing the activity of exogenous carcinogens through modulating metabolic activation and/or detoxification, or stimulating the production of the short-chain fatty acid, butyrate. However, modern analytical techniques suggest that an important consequence of a modified bacterial community could be a change in the expression not only of a range of different bacterial genes in bowel contents, but also in the bowel mucosa of the host. Analogous with observations with probiotics, the stimulation of cytokines and modification of immune responses could be important in producing beneficial effects. Compared with transitory effects of probiotics, the prebiotic action of fermentable carbohydrates potentially provide the opportunity for sustainable modulation of activity of the gut microbiota. However, their mechanisms of action in humans are speculative, and research aimed at providing an integrated view of the gut microbiota and dietary fibre nutrition of humans needs to be developed.

Research paper thumbnail of Coliforms and enterococci isolated from the intestinal tract of conventional mice

Microbial Ecology, 1979

Coliforms and enterococci were isolated from the intestinal tract of infant (12-day-old) and adul... more Coliforms and enterococci were isolated from the intestinal tract of infant (12-day-old) and adult (6-to 8-week-old) conventional mice. Eighty coliform isolates and eighty enterococcal strains were grouped according to their ability to ferment or hydrolyze various substrates. Sixty-one of the coliform isolates were identified as Escherichia coli. The remaining 19 strains were similar to E. coli, but did not produce/3-galactosidase. The enterococci belonged to two species: Streptococcus faecium and S. faecalis. Four biotypes of S. faecium and two biotypes of S. faecalis were detected. Xylosefermenting enterococci were isolated with a higher frequency from infant mice than from adults.

Research paper thumbnail of Analysis of the large bowel microbiota of colitic mice using PCR/DGGE

Letters in Applied Microbiology, 2005

R . B I B I L O N I , M . A .

Research paper thumbnail of The bacteriology of biopsies differs between newly diagnosed, untreated, Crohn's disease and ulcerative colitis patients

Journal of Medical Microbiology, 2006

The bacterial community (microbiota) that inhabits the gut of humans appears to be an important s... more The bacterial community (microbiota) that inhabits the gut of humans appears to be an important source of antigens that drive the chronic immunological processes characteristic of Crohn's disease (CD) and ulcerative colitis (UC). Most of the members of the microbiota have not yet been cultured, but nucleic-acid-based methods of detection and enumeration can provide information about the community. This investigation used these methods to obtain information about the bacteria associated with mucosal surfaces in the gut of 20 CD and 15 UC patients. Biopsies were collected from inflamed and non-inflamed sites in the intestines of newly diagnosed, untreated patients. Biopsies were also collected from several intestinal sites of 14 healthy subjects. The bacterial collections associated with the biopsies were analysed by generating PCR/denaturing gradient gel electrophoresis (DGGE) profiles, the preparation of 16S rRNA gene clone libraries, and qualitative PCR to detect specific groups of bacteria. The total numbers of bacteria associated with the biopsies were determined by real-time quantitative PCR. DGGE profiles generated from the terminal ileum and various colonic regions were characteristic of each individual but differed between subjects. DGGE profiles and 16S rRNA gene libraries showed that the bacteria associated with inflamed and non-inflamed tissues did not differ. UC patients had more bacteria associated with biopsies than did CD patients (P<0?01). Statistical analysis of the composition of 16S rRNA gene libraries showed that the bacterial collections in UC and CD patients differed (P<0?05). Unclassified members of the phylum Bacteroidetes were more prevalent in CD than in UC patients. Therefore, the types and numbers of bacteria associated with biopsy samples were distinctly different for UC and CD patients. The observations made in this study should permit targeting of specific bacteriological abnormalities in investigations of the pathogenesis of inflammatory bowel diseases and provide targets for medical interventions.

Research paper thumbnail of Differential clustering of bowel biopsy-associated bacterial profiles of specimens collected in Mexico and Canada: what do these profiles represent?

Journal of Medical Microbiology, 2008

Research paper thumbnail of Testing probiotic strain Escherichia coli Nissle 1917 (Mutaflor) for its ability to reduce carriage of multidrug-resistant E. coli by elderly residents in long-term care facilities

Journal of Medical Microbiology, 2011

A high carriage rate of multidrug-resistant Escherichia coli (MDREC) was observed in elderly resi... more A high carriage rate of multidrug-resistant Escherichia coli (MDREC) was observed in elderly residents in long-term care facilities. A double-blinded, placebo-controlled trial was carried out to determine whether the probiotic product E. coli strain Nissle 1917 (Mutaflor) would compete with MDREC in the bowel and thereby reduce the prevalence of the multiresistant bacteria in faeces and urine. Sixty-nine patients excreting norfloxacin-resistant E. coli were randomized to probiotic or placebo groups and administered capsules twice daily. The daily dose of probiotic was 5¾10 9 -5¾10 10 bacteria. Faecal and urine samples were cultured at baseline and during and after the treatment period. A reduction in baseline carriage was not influenced by probiotic administration. The probiotic strain was detected in faecal specimens collected during the treatment period of only two out of 12 probiotic group subjects that were tested. Genotyping of norfloxacin-resistant E. coli isolates showed that 32 strains were prevalent among the patients. Thus, E. coli Nissle 1917 does not have the capacity to compete effectively with MDREC in the bowel of elderly patients. %paper no. jmm025874 charlesworth ref: jmm025874& Clinical microbiology and virology Abbreviations: ESBL, extended-spectrum b-lactamase; LTCF, long-term care facility; MDR, multidrug resistant; MDREC, MDR Escherichia coli; UPGMA, unweighted pair group method with arithmetic mean.

Research paper thumbnail of The microflora of the pig stomach and its possible relationship to ulceration of the pars oesophagea

Journal of Comparative Pathology, 1970

Research paper thumbnail of A differential effect of 2 probiotics in the prevention of eczema and atopy: A double-blind, randomized, placebo-controlled trial

Journal of Allergy and Clinical Immunology, 2008

The role of probiotics in prevention of allergic disease is still not clearly established, althou... more The role of probiotics in prevention of allergic disease is still not clearly established, although early reports suggested Lactobacillus GG halved the risk of eczema at 2 years. To determine whether probiotic supplementation in early life could prevent development of eczema and atopy at 2 years. Double-blind, randomized placebo-controlled trial of infants at risk of allergic disease. Pregnant women were randomized to take Lactobacillus rhamnosus HN001 (L rhamnosus), Bifidobacterium animalis subsp lactis strain HN019 or placebo daily from 35 weeks gestation until 6 months if breast-feeding, and their infants were randomized to receive the same treatment from birth to 2 years (n = 474). The infant&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s cumulative prevalence of eczema and point prevalence of atopy, using skin prick tests to common allergens, was assessed at 2 years. Infants receiving L rhamnosus had a significantly (P = .01) reduced risk of eczema (hazard ratio [HR], 0.51; 95% CI, 0.30-0.85) compared with placebo, but this was not the case for B animalis subsp lactis (HR, 0.90; 95% CI, 0.58-1.41). There was no significant effect of L rhamnosus (HR, 0.74; 95% CI, 0.46-1.18) or B animalis subsp lactis (HR, 0.82; 95% CI, 0.52-1.28) on atopy. L rhamnosus (71.5%) was more likely than B animalis subsp lactis (22.6%) to be present in the feces at 3 months, although detection rates were similar by 24 months. We found that supplementation with L rhamnosus, but not B animalis subsp lactis, substantially reduced the cumulative prevalence of eczema, but not atopy, by 2 years. Understanding how Lactobacilli act to prevent eczema requires further investigation.

Research paper thumbnail of Commentary: Remembrance of microbes past

International Journal of Epidemiology, 2004

Research paper thumbnail of Bifidobacterium animalis causes extensive duodenitis and mild colonic inflammation in monoassociated interleukin-10-deficient mice

Inflammatory Bowel Diseases, 2009

Background-We recently showed that Bifidobacterium animalis is more prevalent within the colons o... more Background-We recently showed that Bifidobacterium animalis is more prevalent within the colons of IL-10 deficient (−/−) mice than in wild type (WT) animals colonized with the same specific pathogen free (SPF) fecal contents. Here we tested the ability of this organism to cause T cell-mediated intestinal inflammation by introducing it into germ-free (GF) IL-10−/− mice.