Principle

The NucleoBond® RNA Soil Mini kit is designed for the purification of RNA from soil and sediment samples.

In combination with the DNA Set for NucleoBond® RNA Soil Mini, RNA and DNA can be isolated from the same soil sample. Thus, purified nucleic acids are suitable e.g., for metagenomic studies, where the genome and transcriptome are analyzed from the same sample.
Most soils contain relatively low amounts of RNA, compared to DNA. Therefore, the sample input needs to be increased in order to gain acceptable RNA yields. The standard protocol of this kit uses four NucleoSpin® Bead Tubes Type A that can be filled with 0.25–0.5 g of one soil sample each, resulting in a total sample amount of 0.25–2.5 µg. This sample input amount will usually result in a RNA yield in the range from 0.25–2.5 μg.

Organisms in a soil sample are lysed by bead beating in the presence of Lysis Buffer E1 (check for precipitated SDS!) and Phenol:Chloroform:Isoamylalcohol. Buffer OPT reduces the adsorption of nucleic acids to clay and mineralic soil components, but will also increase the contamination with humic acids if present. Performance cannot be predicted and depends on the soil composition, but as a rule of thumb a sample with a high content of organic and humic components, e.g., forest soil, should be lysed without Buffer OPT while predominantly mineralic soils, e.g., river sediments and clay, should be lysed with Buffer OPT.

Unlysed components are sedimented by centrifugation. The supernatant of the bead tube is transferred into one fresh 1.5 mL tube and mixed with Binding Buffer E2. The incubation and centrifugation steps that follow can be used to prepare the NucleoBond® RNA Mini Columns. The columns are fixed on a NucleoBond® Rack Small or by the use of supplied Plastic Washers on top of a standard laboratory flask or a 50 mL centrifuge tube.

Features