Related Experiment Video
Updated: Jun 19, 2026

Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate
Published on: April 6, 2022
THE KILLING OF CERTAIN BACTERIA BY X-RAYS
1Laboratories of The Rockefeller Institute for Medical Research.
Abstract:
Both copper K X-rays and the soft general radiation from a tungsten tube operated at 12 KV kill B. coli and B. aertryke in a linearly exponential fashion. Within the experimental limits, the two organisms appear to be equally sensitive to these radiations. By making use of the fact that X-ray energy is absorbed in quanta, an approximate picture can be formed of the mechanism of this destructive action. If the average numbers of quanta (alpha) absorbed per bacterium per second are calculated from measurements of air ionization using the quantities outlined in the text, survival ratios for these bacilli can be approximately represented by the equations See PDF for Equation for filtered copper rays and See PDF for Equation for unfiltered copper rays (peak voltage = 34 KV). In terms of the foregoing interpretation this means that when death results, it is caused by the absorption of a single X-ray quantum of energy. Since only about one in twenty of the absorbed quanta kills, the sensitive cell constituents whose destruction leads to cell death must have a volume which is less than 0.06 of the bacterium itself.
More Related Videos
05:57The Synergistic Effect of Visible Light and Gentamycin on Pseudomona aeruginosa Microorganisms
Published on: July 2, 2013
09:29In Vivo Investigation of Antimicrobial Blue Light Therapy for Multidrug-resistant Acinetobacter baumannii Burn Infections Using Bioluminescence Imaging
Published on: April 28, 2017
Related Concept Videos
Physical Methods for Controlling Microbial Growth: Radiation and Filtration
X-ray Imaging
Physical Methods for Controlling Microbial Growth: Temperature
Inhibitors of Bacterial DNA Synthesis
Methods of Sterilization I: Physical Methods
Steam sterilization uses non-toxic, low-cost moist heat in the form of saturated steam under pressure, which is fast, microbicidal, and sporicidal, and quickly warms and penetrates fabrics. Autoclaves, or steam sterilizers, expose each item to direct steam contact for a predetermined time at the necessary...
Biological Methods for Microbial Control