Extraction and purification of DNA from termite mounds, presence of bacterial DNA.

In tropical ecosystems, termite activities induce changes in the chemical and physical properties of soils. The question then arises as to whether or not termites affect the presence of natural microbial communities. Several reports have pointed out the difficulty of recovering bacteria from natural environments by traditional methods of cell cultivation, only a small fraction of the total microbial biomass being cultivable. With the advances in molecular technologies, informative macromolecules like DNA become accessible without requiring any prior cell isolation or cultivation. A critical step was to develop an efficient method for extracting and purifying DNA from termite mounds, a prerequisite for any molecular study using PCR (Polymerase Chain Reaction). In fact, chemical and physical properties of the termite mounds especially that of soil-feeders (i.e., clay-like texture, high organic carbon and humic acid contents) critically impede good DNA recovery and purification. A diversity of mounds of various trophic group termites (soil-feeders Cubitermes subarquatus, Thoracotermes macrothorax, Noditermes lamantanus, Procubitermes niapuensis; fungus-growers : Odontotermes sp) was submitted to the analysis. DNA recovery was significantly higher in sail-feeder mounds than in control soils. Using specific amplification (PCR) the presence of bacteria was assessed in all the constructions studied.