| BackgroundThe human being is "the super organism" composed by 10% human body cells and 90% microorganism cells. The human endogenous gut microflora is an immensely diverse ecosystem and approximately 1014,1000 kinds of microorganisms inhabiting there. Gastro-intestine was divided into physiological symbiosis with the host bacteria (eg. Bacteroidaceae, Bifidobacterium, Bacteroidetess, etc.), and the conditions of the host symbiotic bacteria, based mainly on facultative anaerobes (eg. intestinal coli, enterococci etc.) and the majority passing bacteria pathogens (eg. Proteus, Vibrio cholerae, Shigella, etc.). The intestinal tract bacteria are mainly in the colon area, all of which are maintaining symbiotic and antagonistic relationship. In digestion, nutrient absorption, energy supply, fat metabolism, immune regulation, drug metabolism, toxicity, and many other aspects they have an effect on human and animal's health.For the study of intestinal microflora, the traditional method is through selective cultivation of microorganisms, or by direct morphological observation to get some information, and then identify and classify them. However, these methods have limits such as:they are laborious and vulnerable to the impact of operating methods; the sensitivity is low; most microorganisms are difficult to or can't be isolated or cultured by using existing technologies. The raising technology could only culture qualitative detection of bacteria and can identify the unknown bacteria. As a result, it cannot correctly reflect both the number of intestinal microbial population and the diversity and further makes human beings not fully understand the relationship between the host and the intestinal microflora. In recent years, with the rapid development of molecular biology, molecular biology techniques in micro-ecology are increasingly widespread, which is characterized by microbial population quickly obtaining qualitative and quantitative data. It makes micro-ecology of the existing research range be further expanded. The 16S rRNA gene-based denaturing gradient gel electrophoresis (denaturing gradient gel electrophoresis, DGGE) techniques quickly and accurately identify the natural environment or human environment, microbial population, and conduct the complex microorganism group structure succession rule research, as well as biological population's dynamic analysis. Especially in the last few years, the domestic and foreign scholars use different molecular biology methods to conduct the research on bacterium 16S rRNA, which already obtained widespread 16SrRNA sequence database, and made the foundation for us to compare the micro ecology research.At present rats and mice are mainly used for the study of the intestinal microflora, and their advantages are small size, easy operateing, fast reproduceing, cheapping, etc. But there are many differences between the rodents and human beings in anatomy, physiology and metabolism. So they are not the good model animals for intestinal tract micro ecology research. However, miniature pigs, on the physiology, anatomy and nutrient metabolism are more similar with human, and some human diseases such as cirrhosis, diabetes, hypertension and some nutritional and metabolic disorders are possible to occur in miniature pig. Currently more and more papers take miniature pigs as experimental material. This thesis studied commonly used laboratory animals mouse (FVB/n and BALB/c), rats (SD and Wister), miniature pigs (Bama miniature pig and Guizhou miniature pig) and human fecal sample by using PCR-DGGE technique to compare the diversity of the microbiota.The diversity, richness and evenness of intestinal flora were analyzed and the similarity of UPGMA cluster analysis results were compared to reflect the features of intestinal flora of these commonly used laboratory animals and to further provide some basic data for intestinal microflora study.Purposes and significanceBy using the comparative micro-ecological approaches, the thesis clarified the commonly used experimental animal including mice, rats and miniature pigs indirectly and directly to compare with the gut flora of human beings, and correctly reflecting the intestinal flora's differences and similarities among human being and those animals.From our work, characteristics of microflora of those commonly used laboratory animals were partly revealed and the advantages of them in applying to the microrcology research were presented.Methods1. Collect healthy adult mice (FVB/n and BALB/c), rats (SD and Wister), miniature pigs (Bama miniatuure pig and Guizhou miniature pig) and human fecal samples to extract total bacterial DNA;2. Respectively use V3 (total bacteria) primer, Lac (Lactobacillus) primer, Bfr (Bacteroides) primer to amplify the extracted DNA;3. Denature the gradient gel electrophoresis (DGGE);4. On each band on gel electrophoresis, use spss13.0 analysis software for data analysis.ResultsBy analyzing the diversity, richness and evenness of intra-and inter-specific of total intestinal bacteria, Lactobacillus and Bacteroides genus by using PCR-DEEG method, no significant differences were found between the genuses of each kind of animals (p>0.05) but obvious distinction were observed in various species(p<0.05).The results from UPGAMA clusting showed that the miniature pig was more highly similar with human beings in intestinal tract bacteria comparing with the mice or rats.
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