Abstract: The present invention provides a method of removing nucleic acid contamination in an amplification reaction which comprises use of a thermolabile DNase and a method of preventing or reducing false positive results due to carry-over in a nucleic acid amplification reaction, said method comprising using a thermolabile DNase to degrade carried-over non-target double-stranded DNA present in the amplification reaction mixture. A thermolabile DNase from the shrimp Pandalus borealis has been identified which is suitable for use in the methods of the invention.

Abstract: The invention relates to new cationic biopolymers with an average molecular weight of 800,000 to 1,200,000 Dalton, a Brookfield viscosity (1% by weight in glycolic acid) below 5,000 mPas, a degree of deacetylation of 80 to 88% and an ash content of less than 0.3% by weight which are obtained by repeatedly subjecting crustacean shells to alternate acidic and alkaline degradation under defined conditions. Compared with known cationic biopolymers of the chitosan type, the new biopolymers form clear solutions and, at the same time, show excellent film-forming properties, despite their high molecular weight.