Diversity Of Rat Microbiota In Vivo And Granger Causality Analysis Based On Monte Carlo Simulation

Symbiosis in vivo is a microbial ecosystem that exists in the body and independent of the host cell.In terms of metabolic processes,they are relatively independent of host cells,and has its own relatively independent metabolic activity system.But based on the view of life symbiosis,they are inseparable from the organism and have a great influence on the metabolic activities of the host.Moreover,more and more evidence shows that the microecological balance of the symbiotic bacteria in the body is closely related to the health level of the body and the occurrence and development of many diseases.For example,a decrease in the abundance of bacteroidetes polymorphism leads to an increase in glutamate,which promotes obesity;Lactobacillus reuteri metabolizes tryptophan,leading to an increase in the number of immune cells that cause intestinal inflammation;The metabolic disorder of short chain fatty acids caused by butyrate producing bacteria leads to the occurrence and development of diabetes;Bacteroidetes,Parobacillus and Escherichia coli induced metabolic imbalance of ?-aminobutyric acid(GABA)promotes the occurrence of neurological diseases;Colibactin-producing Escherichia coli causes colorectal cancer by metabolizing colibactin-mediated DNA damage.Therefore,the study of the relationship between the symbiotic microbiota in vivo has great significance for the exploration of health and disease.At present,the relationship between the symbiotic bacteria in rats is studied and discussed.First,multiple tissues and sites of rats were sampled,and the abundance of symbiotic bacteria in each sample at different time points in time series was obtained by 16 S rDNA high-throughput sequencing.Then the correlation analysis of the symbiotic flora was carried out by diversity analysis and principal component analysis,and the bacteria with higher correlation were screened out.Then,by introducing the method of Bivariate Granger Causality test to analysis the cause-and-effect relationship between the high correlation microflora,and explore the relationship between the symbiotic bacteria in rats.Finally,aiming at the stability of time series in Bivariate Granger Causality test analysis,extends the discussion of Granger causality based on Monte Carlo Simulation.The results showed that the degree of interrelationship between symbiotic bacteria in the blood was higher than in the gut.Further,Granger causality test was conducted for highly correlated microbiota in blood samples and gut samples respectively.It was found that a high confidence of Granger causal relationship between Veillonellaceae and Bacteroidaceae in the blood samples;In gut samples,the Granger causal relationship between Veillonellaceae and Bacteroidaceae also has a high confidence;And the Granger causality between Ruminococcaceae and Enterobacteriaceae in gut samples also has a high confidence.Finally,it was found that Bacteroidaceae and Enterobacteriaceae,respectively as one of the Granger reasons,affected the distribution of virongella and Ruminococcaceae in the structure of the bacterial community.This study innovatively applied Granger causality test method to the analysis of causal relationship between microbiota in vivo,extended the Monte Carlo Simulation of Granger Causality,and obtained relatively significant results.This laid a certain foundation for the later research on the relationship between the bacterial communities in the microbial ecosystem,even provides a new idea for the study of symbiotic bacteria in vivo between health and disease in the future.