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Stability of Ribonucleoprotein Particles 



of Escherichia coli 



ELLIS T. BOLTON 



Department of Terrestrial Magnetism- 

 Carnegie Institution of Washington 



BILL H. HOYER DANIEL B. RITTER 



Rocky Mountain Laboratory 



National Institute of Allergy and Infectious Diseases 



U. S. Public Health Service, Hamilton, Montana 



Investigations concerned with the structure and function of ribonucleopro- 

 teins of microorganisms require particle preparations that are representative, 

 reproducible, and stable. This report presents some results of exploratory 

 studies in which the analytical ultracentrifuge was used to assess the influence 

 of various suspending media on the ribonucleoproteins of "Escherichia coli. 



METHODS 



E. coli, B (ATCC 11303) harvested during the exponential phase of growth 

 in a glucose-salts culture medium * was used for all studies. The bacteria were 

 washed and resuspended (25 mg dry weight of bacteria per milliliter) in ap- 

 propriate buffer solutions and disrupted by means of a modified French pres- 



1 The composition of C medium and other culture conditions may be found in 

 Roberts et al., Studies of Biosynthesis in Escherichia coli, Carnegie Inst. Wash. Publ. 607, 

 Washington, D. C, 1955. 



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