title: Improved yield of high molecular weight DNA coincides with increased microbial diversity access from iron oxide cemented sub-surface clay environments.
abstract: Despite over three decades of progress, extraction of high molecular weight (HMW) DNA from high clay soils or iron oxide cemented clay has remained challenging. HMW DNA is desirable for next generation sequencing as it yields the most comprehensive coverage. Several DNA extraction procedures were compared from samples that exhibit strong nucleic acid adsorption. pH manipulation or use of alternative ion solutions offered no improvement in nucleic acid recovery. Lysis by liquid N2 grinding in concentrated guanidine followed by concentrated sodium phosphate extraction supported HMW DNA recovery from clays high in iron oxides. DNA recovered using 1 M sodium phosphate buffer (PB) as a competitive desorptive wash was 15.22±2.33 µg DNA/g clay, with most DNA consisting of >20 Kb fragments, compared to 2.46±0.25 µg DNA/g clay with the Powerlyzer system (MoBio). Increasing PB concentration in the lysis reagent coincided with increasing DNA fragment length during initial extraction. Rarefaction plots of 16S rRNA (V1-V3 region) pyrosequencing from A-horizon and clay soils showed an ∼80% and ∼400% larger accessed diversity compared to the Powerlyzer soil DNA system, respectively. The observed diversity from the Firmicutes showed the strongest increase with >3-fold more operational taxonomic units (OTU) recovered.
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hurt
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Robeson
authors.affiliation: Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America.
authors.forename: Migun
authors.initials: M
authors.lastname: Shakya
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: James G
authors.initials: JG
authors.lastname: Moberly
authors.affiliation: Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America.
authors.forename: Tatiana A
authors.initials: TA
authors.lastname: Vishnivetskaya
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: Baohua
authors.initials: B
authors.lastname: Gu
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: Dwayne A
authors.initials: DA
authors.lastname: Elias
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001419:Bacteria / Q000235:genetics*; D044822:Biodiversity; D000077215:Clay; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics*; D004777:Environment; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D000538:Aluminum Silicates; D004269:DNA, Bacterial; D005290:Ferric Compounds; D012336:RNA, Ribosomal, 16S; D012987:Soil; C000499:ferric oxide; D000077215:Clay