title: Altered nucleic acid partitioning during phenol extraction or silica adsorption by guanidinium and potassium salts.
abstract: Nucleic acids were found to partition into the phenol phase during phenol extraction in the presence of guanidinium at certain concentrations under acidic conditions. The guanidinium-concentration-dependent nucleic acid partitioning patterns were analogous to those of the nucleic acid adsorption/partitioning onto silica mediated by guanidinium, which implied that phenol and silica interact with nucleic acids through similar mechanisms. A competition effect was observed in which the nucleic acids that had partitioned into the phenol phase or onto the silica solid phase could be recovered to the aqueous phases by potassium in a molecular weight-salt concentration-dependent manner (the higher molecular weight nucleic acids needed higher concentrations of potassium to be recovered, and vice versa). Methods were developed based on these findings to isolate total RNA from Escherichia coli. By controlling the concentrations of guanidinium and potassium salts used before phenol extraction or silica adsorption, we can selectively recover total RNA but not the high molecular weight genomic DNA in the aqueous phases. Genomic DNA-free total RNA obtained by our methods is suitable for RT-PCR or other purposes. The methods can also be adapted to isolate small RNAs or RNA in certain molecular weight ranges by changing the salt concentrations used.
authors.affiliation: Institute of Molecular Biology and Biotechnology, Anhui Normal University, Wuhu 241000, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.forename: Liefeng
authors.initials: L
authors.lastname: Ling
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Song
authors.forename: Ruirui
authors.initials: R
authors.lastname: Su
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhu
mesh_terms: D000327:Adsorption; D001671:Biochemistry / Q000379:methods*; D011232:Chemical Precipitation; D004269:DNA, Bacterial / Q000302:isolation & purification; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics; D016680:Genome, Bacterial / Q000235:genetics; D019791:Guanidine / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D009696:Nucleic Acids / Q000302:isolation & purification*; D010636:Phenols / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D012329:RNA, Bacterial / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012492:Salts / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012996:Solutions
chemical_list: D004269:DNA, Bacterial; D009696:Nucleic Acids; D010636:Phenols; D012329:RNA, Bacterial; D012492:Salts; D012996:Solutions; D012967:Sodium Dodecyl Sulfate; D012822:Silicon Dioxide; D019791:Guanidine; D011188:Potassium