Many different procedures are used to isolate nucleic acids from Mycobacterium, however most have the common feature of disrupting the bacteria with 100 μm silica or zirconium beads. Though crude silica and zirconium beads can be used for disruption, pre-treatment of the beads prior to homogenization can significantly affect the yields of DNA. Raw silica and zirconium beads contain fine materials that interfere with isolation, similar to those found in chromatography gels. Consequently these fine suspended solids need to be removed. Furthermore, the beads themselves provide a surface for non-specific adsorption of nucleic acids. Modifying the beads with a low-binding surface helps to minimize nucleic acid loss due to non-specific adsorption.
Acid washing of beads removes suspended solids (i.e., fines) and soluble contaminants. Testing from an independent laboratory has shown that acid washing alone can increase yield three fold over crude beads. Acid washed beads can be further processed by baking to render the beads free of possible nucleases. This is an especially important step when RNA is being isolated.
Though acid washed beads provide better yields than unwashed beads, the bead surface still readily adsorbs solutes non-specifically. Treating the surface to reduce non-specific adsorption has been shown to increase yields. A proprietary process developed by OPS Diagnostics provides a low binding surface that doubles yield from acid washed beads alone. Low binding beads can therefore yield six times the nucleic acids of untreated beads. These low binding beads help to provide greater sensitivity in detecting bacteria when the number of microbes in the original sample is low.
| Item | Product Number |
| Low Binding Silica Beads, 100 μm, 200 gm | BLBG 100-200-11 |
| Low Binding Zirconium Beads, 100 μm, 250 gm | BLBZ 100-250-14 |
| Molecular Biology Grade Silica Beads, 100 μm, 200 gm | BMBG 100-200-16 |
| Molecular Biology Grade Zirconium Beads, 100 μm, 250 gm | BMBZ 100-250-17 |
| Acid Washed Silica Beads, 100 μm, 200 gm | BAWG 100-200-10 |
| Acid Washed Zirconium Beads, 100 μm, 250 gm | BAWZ 100-250-15 |
Also see High Throughput Homogenizers if multiple samples are routinely processed.