Transcriptome analysis across diverse biological species in the human gastric environment 219N
Total RNAs were extracted from frozen tissue samples using Trizol reagents (Invitrogen, Carlsbad, CA, USA). One microgram of total RNA was used as a starting material for a 50-bp paired-end transcriptome-sequencing protocol using an Illumina GAIIx sequencer (Illumina, San Diego, CA, USA).  The reads were aligned to all the human RefSeq transcripts (release 38) and the human genome assembly (build 37, hg19), allowing up to two mismatches. Alignments were performed using ELAND software (Efficient Large-scale Alignment of Nucleotide Databases) within the Illumina genome analyzer pipeline. Reads that mapped to any Refseq transcript or human genome were discarded.