Study Of The Effects Of Appendix On The Gut Microbiota

Background and aimsThere are 1013-1014 bacterium inhabiting the human gut,of which the number is 10 times more than the number of the cells of the human body.The existence of the gut microbiota not only strongly strengthens the ability of the human in metabolizing endogenous and exogenous substance,but also contribute to materials synthesis,such as vitamins.The onset and development of plenty of diseases,such as inflammatory bowel disease,colorectal cancer,nowadays is believed to connect with the abnormity of the gut microbiota.In the past,appendix was considered to be a residual organ without function,however,the understanding of the function of appendix has changed in recent years.More and more reports have connected appendix with diseases of the digestive system,such as increased incidence of inflammatory bowel disease after appendectomy.What is now assumed is that the change of the morbidity of the diseases is related to the mirobiota and immune function of the appendix,but the underling mechanisms is still unknown or obscured.16Sr DNA and Metagenome sequencing are two of the common high-throughput sequencing methods in the study of mocrobiota in the recent years,which are now widely used in the study on microbiota in human body,agriculture and environment.In this study,we intended to study the microbiota in the stools from two groups of volunteers?experimental group:subjects with the history of acute appendicitis and appendectomy,control group:subjects without the history of acute appendicitis and appendectomy?with 16sr DNA and metagenome sequencing.Based on the sequencing results,we intend to study the microbiota profile and their functions of the experimental group,and the differences of it compared to the control group,so as to find the possible connection between the difference and the changed incidence of some diseases,such as IBD and CRC.Methods16sr DNA sequencingWe collected stools of subjects from the two groups.One stool sample was collected per subject.When all the stools were collected,we extracted the total DNA in the stools,and then amplify the V4 fragment of the 16sr DNA before 16sr DNA sequencing.With the sequencing data,we get the information of the species of bacterium in the stools with the data on the GreenGene database,which we used for further analysis of the bacterium later.Metagenome SequencingWe extracted DNA from part of the remained samples used for 16sr DNA sequencing,then went for a series of procedures,namely sample testing,library construction,sequencing,metagenome assembling,gene predict,tax annotation,and function annotation,finally we analyzed the mirobiota from the stools with the result data.Results1.Bacteria was predominant in both groups,which took up more than 95%of the whole mirobiota.The main phylums of the bacteria were Bacteroidetes,Firmicutes and Proteobacteria in both groups;2.Differences were found in the communities and abundance of the microbiota from the stool samples,and G_Prevotella,G_Sutterella,S_Prevotella_bryantii,S_Bacteroides_sp_CAG₅30,S_Bacteroides_coprophilu,S_Oscillibacter_sp_ER4,S_Ruminococcus_sp_C AG₁77,S_Prevotella_sp_KHD1,S_Clostridium_sp_CAG₁38,S_Clostridium_sp_CAG₁27,S_Prevotella_sp_CAG₅20,S_Bacteroides_plebeius,S_Bacteroides_plebeius_CAG₂11 were richer in the control group,while S_Bacteroides_fragilis,S_Bacteroidesu_niformis richer in the experimental group;3.Differences were found in the functions of the microbiota from the stool samples,genes in the cardiovascular diseases,endocrine and metabolic diseases,biosynthesis of other secondary metabolites,lipid metabolism pathways were richer in the experimental group,while genes in the cell growth and death,replication and repair,translation,energy metabolism,nucleotide metabolism and amino acid metabolism pathways were less than the control group.ConclusionsAppendectomy has changed the community and the function of the gut microbiota,which means that appendix has impacts on the gut microbiota.Specific taxa and genes are richer in the experimental group,which might be relative to the changed incidence of diseases like CRC,IBD and also diseases from other systems.