Cell and organelle lysis
The source of extracellular DNA in water samples is cells that cover a
broad range of properties and characteristics. In cells without a cell
wall (animal cells and protozoa), water chemistry influences cytolysis,
whereby osmotic pressures cause cell lysis if not maintained. This
converts cellular DNA to dissolved DNA (Figure 1). Conversely, the
release of DNA from cells with cell walls (plant cells) results from
enzymatic breakdown of the polysaccharides and lignin composing their
structure32.
Thus, the activity of extracellular microbial enzymes is likely the
rate-determining step in plant cell lysis. The activity itself increases
with increasing enzyme concentration and is sensitive to both
temperature and ultraviolet (UV) light
exposure33.
Inside eukaryotic cells are cytoplasmic organelles that contain
mitochondrial and chloroplast DNA and consist of a double lipid bilayer
membrane and like animal cells, undergo similar lysis processes.