Next Generation Sequencing
 16S rRNA gene amplicon seqeuncing for V1V3 or V3V4 hypervariable regions for prokaryotic taxon identification
 Ribosomal Internal Transcribed Spacer (ITS) region sequencing for fungal taxon identification
 Meta-genomic sequencing for total DNA isolated from samples.
Comprehensive data analyses and interpretation
Dr. Paster and Dr. Chen are well known in the oral bacterial scientific community with many publications that typically focus on, but not restricted to, the human oral and nasal cavities. For 16S rDNA datasets, the compositional data analysis (CoDa) approach will be used to prevent negative correction bias to ensure optimal results and interpretation.
Experimental design
 Sample preparation
 DNA extraction (as needed)
 PCR primers for 16S rRNA gene amplicon NGS sequencing
 DNA library preparation for high-coverage microbial genomic sequencing
 Nucleic acid library preparation for metagenomic sequencing
State-of-the-art data analyses
 Sequence quality filtering and amplicon sequence variants (ASVs) inference - DADA2
 Taxonomy Assignment:
 Alignment based algorithm: A robust species-level taxonomy assignment based on best sequence alignment to a set of 16S rRNA reference sequences originated from HOMD, NCBI and GreenGene. This algorithm works on both human oral/nasal and non-oral/non-nasal samples and are independent of sequenced regions (Al-Hebshi et al, 2015).
  K-mer based algorithm: Samples from human oral/nasal cavity - Oral/nasal habitat-specific training sets (patent pending) in naïve Bayesian classification to achieve species/supraspecies level taxonomic assignment of 16S rRNA gene-derived ASVs (Escapa et al, 2020) (Watch the Youtube video abstract below)

 Flowchart of the Taxonomy Assignment Pipeline:
 Downstream 16S rRNA amplicon based data analyses:
 Visual Analysis - Interactive taxonomy bar plots
 Compositional data analysis (CoDa) - centered log ratio (clr) data transformation (Aitchison 1986)
 Distance/Dissimilarity metric measurement - (Aitchison et al 2000) Aitchison distance
 Microbial profiles - heatmap and clustering
 Phylogenetic trees with relative abundance
 Microbial diversity analyses - alpha and beta diversities, core microbiome analysis
 Variance-based compositional principal component (PCA) biplot for beta-diversity exploration
 Correlation analysis - SPARCC (Friedman and Alm, 2012)
 Differential Abundance Analysis - ALDEx2
 LEfSe (Linear discriminant analysis Effect Size) determines the features (organisms, clades, operational taxonomic units, genes, or functions) most likely to explain differences between classes (non-compositional test)
Meta-genomic and meta-transcriptomic NGS data analysis
 Reads quality trimming and removal of human sequences
 Microbiome community analysis based on 16S rRNA genes identified from metagenomic/metatranscriptomic data
 Metagenome-assembled genomes (MAGs) based analysis
 Microbial functional and pathway enrichment analysis
 Association of metadata with functional features
 Flowchart of the meta-genomic/meta-transcriptomic pipeline:
Consultation and Collaboration
Dr. Paster is an internationally known oral mcirobiome researcher. He can provide consultation on microbiome research projects and asssist with data intepretation and writing. His service can also be on the collaboration basis. Please contact Dr. Paster for any of the following services.
Professional data interpretation
Assist in writing reports, grants, and manuscripts
Provide figures for manuscripts and grants
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Page last updated: November 12, 2020 10:58:45