Nachweis spektraler Unterschiede im Inaktivierungsmechanismus von Escherichia coli mit Hilfe der Wärme-Reaktivierbarkeit und anderer Kriterien
2014
Stein, Werner | Harm, Walter
The following experimental results were obtained: Inactivation of Escherichia coli, strain B, by wave-lengths from 254 mμ to 313 mμ is strongly heat-reactivable with a dose reduction ratio of about 12 : 1 to 7 : 1, respectively. But there is little or no heat-reactivation after inactivation by wave-lengths of 334 mμ, 366 mμ or about 560 mμ. Resistance of strain B/r, closely correlated with the heat-reactivability of strain B, disappears at wave-lengths ≧ 334 μ too. The inactivation efficiency of quanta absorbed by the whole bacterium decreases between 254 mμ and 366 mμ by a factor of nearly 10³; if only absorption by DNA of the cell is considered, the factor ist also 10³. Hence, it is concluded that a rapid change in the mechanism of inactivation takes place just between 313 mμ and 334 mμ, which is probably caused by the critical limit of a definite quantum absorption. As an interpretation for inactivation by long UV and visible light denaturation of proteins and lethal mutations are discussed.
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