Nucleic acid precautions

Collecting samples of ancient nucleic acids is a delicate operation that requires what are basically surgical procedures. It is advantageous, whenever possible, that the samples be collected at excavation sites and precautions taken to ensure that they do not become contaminated with other, particularly more recent, nucleic acids. At high temperatures and humidity, nucleic acids decay quickly. Well-preserved ancient nucleic acids can, therefore, be expected in sites where low temperatures and a dry environment prevail, as, for example, in cold, desert areas of the world. Once collected, the samples need to be isolated from any other remaining materials until they can be amplified by PCR and their chemical composition and structure can then be studied. 

Figure 9.17. Overview of the manufacture of Ceprotin. As the active ingredient is derived directly from pooled human plasma, particular emphasis is placed upon ensuring that the finished product is pathogen-free. Precautions entail the incorporation of two independent viral inactivation steps and high-resolution chromatographic purification. Additionally, extensive screening of plasma pool source material for blood-borne pathogens is undertaken. Viral screening is undertaken using a combination of immunoassay and PCR analysis for the presence of viral nucleic acid...

All of these improvements are incorporated into commercial instruments designed for nucleic acid chromatography. It is also important to follow preventive maintenance procedures and check filters for signs of colored deposits. Since double-stranded DNA is more susceptible to contamination, the use of precautions with respect to the method and the system is much more critical than when the... 

Safety precautions are necessary in most models, the current is automatically switched off as soon as the lid of the apparatus is removed. High-voltage procedures are commonly used for peptides and oligonucleotides, e.g. for mixtures obtained by partial hydrolysis of proteins or nucleic acids. 

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