Project description:Purpose: This study aims to compare and analyze the differences in bacterial community composition in fecal samples from mice treated with Control(DW), Vancomycin (VAN), Ampicillin (AMP), Neomycin (NEO), Metronidazole (MET), and a combination of all antibiotics (ALL, VANM) using 16S rRNA sequencing. Methods: Each antibiotics treated mice's fecal samples were collected and stored -80'c until analyzation. DNA was extracted using the NucleoSpin DNA Stool Kit (MACHEREY-NAGEL) following the manufacturer’s protocol. Metagenomic sequencing was performed on an Illumina MiSeq platform (Illumina), targeting the V3 and V4 regions of the 16S rRNA gene according to the manufacturer's instructions. PCR products were purified using AMPure XP beads, and sequencing adapters were added using the Nextera XT Index Kit (Illumina). The library was further purified with AMPure XP beads and quantified using automated electrophoresis with the TapeStation System (Agilent). Sequencing was performed using the MiSeq v3 reagent kit (Illumina), following the manufacturer’s protocol. Results: QIIME2 (v2023.02) was used to process and analyze 16S rRNA gene amplicon sequencing data, from sequence preprocessing to taxonomic classification. Paired-end sequences were merged and quality-filtered using Deblur. The resulting amplicon sequence variants (ASVs) were used for downstream analyses. Conclusions: Our study presents a comparative analysis of bacterial community composition in fecal samples from antibiotic-treated mice. We observed that microbiota composition varied distinctly depending on the type of antibiotic administered.
Project description:Functional redundancy in bacterial communities is expected to allow microbial assemblages to survive perturbation by allowing continuity in function despite compositional changes in communities. Recent evidence suggests, however, that microbial communities change both composition and function as a result of disturbance. We present evidence for a third response: resistance. We examined microbial community response to perturbation caused by nutrient enrichment in salt marsh sediments using deep pyrosequencing of 16S rRNA and functional gene microarrays targeting the nirS gene. Composition of the microbial community, as demonstrated by both genes, was unaffected by significant variations in external nutrient supply, despite demonstrable and diverse nutrient–induced changes in many aspects of marsh ecology. The lack of response to external forcing demonstrates a remarkable uncoupling between microbial composition and ecosystem-level biogeochemical processes and suggests that sediment microbial communities are able to resist some forms of perturbation.
Project description:We investigated the microbial composition in the colon of rats with diet-induced obesity. Fecal samples were collected after eight weeks on the special diet, and 16S rRNA sequencing was employed to analyze microbial communities. Our findings revealed distinct microbial profiles between rats fed a LFD and HFD.
Project description:Functional redundancy in bacterial communities is expected to allow microbial assemblages to survive perturbation by allowing continuity in function despite compositional changes in communities. Recent evidence suggests, however, that microbial communities change both composition and function as a result of disturbance. We present evidence for a third response: resistance. We examined microbial community response to perturbation caused by nutrient enrichment in salt marsh sediments using deep pyrosequencing of 16S rRNA and functional gene microarrays targeting the nirS gene. Composition of the microbial community, as demonstrated by both genes, was unaffected by significant variations in external nutrient supply, despite demonstrable and diverse nutrient–induced changes in many aspects of marsh ecology. The lack of response to external forcing demonstrates a remarkable uncoupling between microbial composition and ecosystem-level biogeochemical processes and suggests that sediment microbial communities are able to resist some forms of perturbation. nirS gene diversity from two salt marsh experiments, GSM (4 treatments, 8 samples, duplicate arrays, four replicate blocks per array, 8 arrays per slide) and PIE (2 treatments, 16 samples, duplicate arrays four replicate blocks per array, 8 arrays per slide)
Project description:The community composition (in terms of abundance, distribution and contribution of diverse clades) of bacteria involved in nitrogen transformations in the oxygen minimum zones may be related to the rates of fixed N loss in these systems. The abundance of both denirifying and anammox bacteria, and the assemblage composition of denitrifying bacteria were investigated in the Eastern Tropical South Pacific and the Arabian Sea using assays based on molecular markers for the two groups of bacteria. The abundance and distribution of bacteria associated with the fixed N removal processes denitrification and anammox were investigated using quantitative PCR for genes encoding nitrite reductase (nirK and nirS) in denitrifying bacteria and hydrazine oxidase(hzo) and 16S rRNA genesin anammox bacteria. All of these genes had depth distributions with maxima associated with the secondary nitrite maximum in low oxygen waters. NirS was mch more abundant than nirK, and much more abundant than the 16S rRNA gene from anammox bacteria. The ratio of hzo:16S rRNA for anammox was low and variable implying greater unexplored diversity in the the hzo gene. Assemblage composition of the abundant nirS-type denitrifiers was evaluated using a funcitonal gene microarray. Of the nirS archetypes represented on the microarray, very few occurred speficically in one region or depth interval, but the assemblages varied significantly. Community composition of denitrifiers based on microarray analysis of the nirS gene was most different between geographical regions. Within each region, the surface layer and OMZ assemblages clustered distinctly. Thus, in addition to spatial and temporal variation in denitrificaiton and anammox rates, both microbial abundance and community composition also vary between OMZ regions and depths.