Schnelle fluorometrische desoxyribosespezifische DNS‐Bestimmung an nicht desintegrierten Mikroorganismen mit 3,5‐Diaminobenzoesäure (DABA). I. Chemisch‐analytische Methodik und Anwendung auf Hefepopulationen

Abstract

The determination of DKA with 3.5-diaminobenzoic acid (DABA) following a DOEBNER-MILLERquinaldine synthesis !PEREZ 1950), the reaction of which is specific for deoxyribose. is rarely known arid used.Hydrolysis of DNA and condensation of liberated deoxyribose with DABA (prepared via ethyl-3,5-dinitrobenzoate) can be performed in an one-step-rcaction resulting in a stable and sensitive fluorescence with favourable excit,ation and emission conditions. I n dependence on the fluorometric equipment amounts of to M "DNA-phosphorus" are detectable. Comparable fluorescence yields are prodnced by DNA-preparations of different origin and G-Ccontent.Interferences are caused by aldehydes of the type R-CH,-CHO, but not by RN'S in manifold excess or other ubiquitous substances.Microorganisms can easily be subjected to that procedure. Thus, investigations on growing yeast populat,ions (exhibiting artificial changes from repressed to derepressed oxidative metabolism) clearly demonstrated the anticipated correlations among specific growth rate, cell number, dry mass, protein and DNA-content. Similar correlations exist among degree of ploidy and DNAcontent of t,he cell.It was found that the quotient of DNA-content/cell to dry mnss,/cell is ponstant for isogenic homozygous strains.