The Gram Complex in Clostridium welchii

Abstract

IT has been reported^1,2 that various Gram-positive micro-organisms may be converted into Gram-negative cytoskeletons by extraction with 2 per cent sodium cholate at 60° C. The extract from Clostridium welchii, for example, contained mainly magnesium ribonucleate, deoxyribonucleic acid and polysaccharide, while the extract from Saccharomyces cerevisiæ was composed chiefly of polysaccharide and magnesium ribonucleate. Cytoskeletons so rendered Gram-negative could be reconverted to Gram-positive forms by treatment under reducing conditions with the cholate extract. The essential component in this replating process was magnesium ribonucleate, and it was shown that magnesium ribonucleate from a variety of sources could be replated on to reduced cytoskeletons of yeast or Cl. welchii. When Gram-positive cells were converted into Gram-negative forms by autolysis, the resulting cytoskeletons could not be replated by magnesium ribonucleate. Short autolytic processes were found to result in the liberation into solution of an essentially intact magnesium ribonucleoprotein which possessed the staining properties of the Gram-positive cells themselves. The nucleoprotein could be dissociated into magnesium ribonucleate and a protein—neither of which separately possessed the property of being able to retain the Gram stain, but which, upon recombination under reducing conditions, formed a complex which stained intensely Gram-positive. In the light of these results, it was suggested that an essential part of the Gram complex is a magnesium ribonucleoprotein. Numerous confirmations of these claims and techniques have been received^3,4,5 from workers in various parts of the world, though recently Mitchell and Moyle⁶ prefer to regard the essential part of the Gram complex as a hypothetical “X/P factor”. However, inasmuch as the results of Mitchell and Moyle show no content of this as yet ill-defined X/P factor in Cl. welchii, which is one of the most intensely staining Gram-positive organisms, we find it difficult to accept their assumption that this factor is an essential component of the Gram complex.