| 1. |
|
|
| 2. |
- Wang, Mei, et al.
(författare)
-
Comparison of bacterial diversity along the human intestinal tract by direct cloning and sequencing of 16S rRNA genes
- 2005
-
Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 1574-6941 .- 0168-6496. ; 54:2, s. 219-231
-
Tidskriftsartikel (refereegranskat)abstract
- Bacterial diversity of the mucosal biopsies from human jejunum, distal ileum, ascending colon and rectum were compared by analysis of PCR-amplified 16S rDNA clone libraries. A total of 347 clones from the mucosal biopsies were partially sequenced and assigned to six phylogenctic phyla of the domain Bacteria: Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, Verrucomicrobia, and Actinobacteria. The jejunum sample had least microbial diversity compared to the other samples and a trend towards highest diversity in ascending colon was observed. The clone libraries of distal ileum, ascending colon and rectum were not significantly different from each other (P > 0.0043), but they differed significantly from the jejunum library (P = 0.001). The population of sequences retrieved from jejunal biopsies was dominated by sequences closely related to Streptococcus (67%), while the population of sequences derived from distal ileum, ascending colon and rectum were dominated by sequences affiliated with Bacteroidetes (27-49%), and Clostridium clusters XlVa (20-34%) and IV (7-13%). The results indicate that the microbial community in jejunum is different from those in distal ileum, ascending colon and rectum, and that the major phylogenetic groups are similar from distal ileum to rectum. (C) 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
|
|
| 3. |
- Wang, Mei, et al.
(författare)
-
High Proportions of Proinflammatory Bacteria on the Colonic Mucosa in a Young Patient with Ulcerative Colitis as Revealed by Cloning and Sequencing of 16S rRNA Genes.
- 2007
-
Ingår i: Digestive Diseases and Sciences. - : Springer Science and Business Media LLC. - 1573-2568 .- 0163-2116. ; 52, s. 620-627
-
Tidskriftsartikel (refereegranskat)abstract
- The pathogenesis of ulcerative colitis (UC) remains unknown. It is thought to be due to an abnormal and uncontrolled immune response to normally occurring constituents of the intestine. Microbial agents appear to be involved in the pathogenesis and intestinal bacteria seem to be an important factor in the development and chronicity. The aim of this study was to investigate the colonic microbiota of a patient with UC. The colonic tissues were taken during surgery from a 12-year-old girl suffering from UC. The microbiota on the colonic samples was studied by cloning and sequencing of amplified 16S rRNA genes. Compared with healthy subjects, alteration of the dominant bacterial group was observed in the UC patient. We found a high incidence of Enterobacteriaceae, Bacteroides fragilis, and the single phylotype of the Faecalibacterium prausnitzii-like "Butyrate-producing bacterium" L2-6. Furthermore, there was a substantial presence of Pseudomonas aeruginosa in the present case of UC. The high proportion of adverse proinflammatory species is striking in the present case compared with more normal situations. Even if those bacteria are not the cause of the UC, they most probably enhance the symptoms of the disease.
|
|
| 4. |
- Wang, Mei, et al.
(författare)
-
Reduced diversity in the early fecal microbiota of infants developing atopic eczema
- 2008
-
Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 121:1, s. 129-134
-
Tidskriftsartikel (refereegranskat)abstract
- Background It might be that early intestinal colonization by bacteria in westernized infants fails to give rise to sufficient immune stimulation to support maturation of regulatory immune mechanisms. Objective The purpose of the present study was to characterize the very early infantile microbiota by using a culture-independent approach and to relate the colonization pattern to development of atopic eczema in the first 18 months of life. Methods Fecal samples were collected from 35 infants at 1 week of age. Twenty infants were healthy, and 15 infants were given diagnoses of atopic eczema at the age of 18 months. The fecal microbiota of the infants was compared by means of terminal restriction fragment length polymorphism (T-RFLP) and temporal temperature gradient gel electrophoresis (TTGE) analysis of amplified 16S rRNA genes. Results By means of T-RFLP analysis, the median number of peaks, Shannon-Wiener index, and Simpson index of diversity were significantly less for infants with atopic eczema than for infants remaining healthy in the whole group and for the Swedish infants when AluI was used for digestion. The same was found when TTGE patterns were compared. In addition, TTGE analysis showed significantly less bands and lower diversity indices for the British atopic infants compared with those of the control subjects. Conclusion There is a reduced diversity in the early fecal microbiota of infants with atopic eczema during the first 18 months of life.
|
|
