Effects Of Copper And Mercury On Microbiota Diversity In Cecum And Rectum Of Mice

To understand the impact of copper and mercury on gut microbes,45 healthy mice were randomly divided to 4 groups: control group(purified water),copper group(500mg/L Cu),mercury group(140mg/L Hg)and copper + mercury group(500mg/L Cu+140mg/L Hg).There were 12 mice in each group.The treated liquid was prepared by adding copper chloride(Cu Cl2)and mercury chloride(HgCl2)to purified water.Samples were collected on the 90 th after treatment.The microbial communities in these samples were analyzed via deep DNA sequencing of the bacterial 16 S r RNA genes characterized by amplifying the V4 region using the Illumina Miseq platform.We got the valid data through filtering the raw data.Species annotation and abundance analysis based on the OTU clustering reveal the microbial species and difference between samples in mice gut using Alpha diversity and Beta diversity analysis.The results were as follows:1、There were 1788171 effective sequences in total.2861 the most abundant bacterial operational taxonomic units(OTUs)were found in rectum and 2913 OTUs in cecum.According to the results of sequence annotation,there were 11 phyla,100 genera.2、In cecum,compared to the control group at the phylum level,Proteobacteria decreased significantly in Cu group(P<0.05);Tenericutes increased significantly in Cu + Hg group(P<0.05).compared to the control group at the genus level.Corynebacterium increased significantly but Staphylococcus,Jeotgailcoccus,and Rikenella decreased significantly in Cu group(P<0.05).Butyricimonas,Dehalobacterium,Coprococcus,Oscillospira and Bilophila increased significantly but Staphylococcus,Jeotgailcoccus,Staphylococcus and Acinetobacter decreased significantly in Hg group(P<0.05).Naeroplasma,Dehalobacterium and Coprococcus increased significantly but Staphylococcus,Jeotgailcoccus and Sporosarcina decreased significantly in Cu + Hg group(P<0.05).3、In rectum,compared with the normal group at the phylum level,the microbial community structures of gut were significant different.Copper and mercury were not only changed the gut microbial of the cecum and rectum in mice,but also destroyed the balance of Microbial colony system.Spirochaetes increased significantly in Cu group(P<0.05);Tenericutes increased significantly in Cu + Hg group(P<0.05).Compared to the control group at the genus level,Dehalobacterium,Coprococcus,Dorea,Oscillospira and Treponema increased significantly but Bacillus,Jeotgailcoccus,Salinicoccus,Staphylococcus and Lgnatzschineria decreased significantly in Cu group(P<0.05).Coprococcus,Oscillospira,Strephylococcus,Dehalobacterium,Butyricimonas and Helicobacter increased significantly but Lgnatzschineria,Salinicoccus,Bacillus,Jeotgailcoccus,Staphylococcus,Lactococcus and Corynebacterium decreased significantly in Hg group(P<0.05).Coprococcus,Oscillospira,Dehalobacterium,Helicobacter and Anaeroplasma increased significantly but Lgnatzschineria,Salinicoccus,Bacillus,Jeotgailcoccus,Staphylococcus and Corynebacterium decreased significantly in Cu + Hg group(P<0.05).The results showed copper and mercury were not only changed the gut microbial of the cecum and rectum in mice,but also destroyed the balance of Microbial colony system.It showed that the abundance of probiotics(Staphylococcus and Jeotgailcoccus)was decreased and the abundance of harmful bacteria Corynebacterium and Helicobacter was increased.That provides a theoretical basis for a more accurate assessment of the risk of intestinal diseases associated with heavy metal intake.