title: 16S rRNA amplicon sequencing of earthworm gut microbiota under Cd/CIP/Cd-CIP stress,             treatment 3-2
design: the V4 and V5 regions of the 16S rRNA gene of microbes were                 amplified with forward primer F515 (5-GTGCCAGCMGCCGCGGTAA-3) and reverse primer R907                 (5-CCGTCAATCMTTTRAGTTT-10)