Influence of Glass and Air on Our Perception of DNA

The chemical and physical properties of glass do not allow it to be considered as an inert material. Therefore, it is necessary to discuss the ability of laboratory glassware to influence the state and properties of aqueous solutions, including DNA solutions. As a demonstration of this ability, it is shown here how contact with glass affects the state of salts in aqueous solutions. In terms of the topic under discussion, it is especially important that sodium salts are very sensitive to these contacts. Thus, it is shown here that contact with glass can affect the formation of fibers from sodium salts of DNA, which were mainly used in X-ray studies aimed at determining the molecular structure and parameters of DNA molecules. Special attention is paid to the fact that laboratory glassware is also sensitive to contact with aqueous solutions, including DNA solutions. That such sensitivity may be important to biologists is also shown here. In particular, it was shown how ignoring the sensitivity of silica glass, from which the photometric cells are made, to electrization gave rise to misconceptions about the spectral properties of aqueous solutions, including DNA solutions. The effect of air dissolved in aqueous DNA solutions on the spectral properties of both these solutions and the photometric cells containing them is also shown. In particular, it was shown that UV absorption of aqueous DNA solutions, which does not contain air, is completely insensitive to heating, and UV absorption of aqueous DNA solutions, which are saturated with air, is supersensitive to heating. In other words, it is shown here that our understanding of the thermal denaturation of DNA, which is reflected in the UV absorption of its aqueous solutions, was formed due to these two types of sensitivity. In the end, a conclusion is proposed here about the significant contribution of glass and air to the creation of traditional ideas about the structure and properties of DNA.