Recent studies on the nature of the antibiotic streptomycin have demonstrated that crude preparations of this substance contain at least two antibiotic entities. One of these is streptomycin itself, now known to be composed of the disaccharide streptobiosamine linked glucosidically to a diguanidine base, streptidine.1 The other is streptomycin B or as it is now called, mannosidostreptomycin.2'3'4In demonstrating the existence of mannosidostreptomycin, Fried and Titus2 made use of the Craig counter-current distribution technique. Evidence was also offered by these authors for the existence of a third form of the antibiotic.3Since paper partition chromatography has proved to be an effective tool in resolving complex mixtures of the penicillins as shown by Goodall and Levi,6 and by Winsten and Spark,7 it was felt desirable to adapt this technique to the streptomycin problem. The present report concerns the development of a paper partition chromatographic method for the separation and identification of the antibiotic entities comprising the streptomycin complex.Recently, Home and Pollard8 have described a method for the identification of streptomycin using paper-strip chromatograms. However, the technique as described by these authors differs from that here reported inasmuch as it does not serve to separate the various forms of streptomycin from one another.The method as developed by the present writers is carried out in a manner analogous to that used in the separation of the penicillins.6'7 Briefly it consists of separating the various forms of streptomycin on a paper-strip chromatogram, using a suitable developing solvent as the mobile phase and water adsorbed on paper as the stationary phase.After developing the chromatogram the solvent is removed and the dried chromatogram is then laid on the surface of nutrient agar previously seeded with specific bacteria whose growth is inhibited by the antibiotics in question. The moist agar leaches the antibiotics from the strip chromatogram, which is then lifted from the surface of the agar. After allowing a suitable incubation period for growth of the bacteria, examination of the agar plate reveals zones of inhibition of growth (1) F.
Dilute solutions of linear alkylbenzene sulfonate (LAS), an anionic detergent, caused strips of epidermis to twist and curl. Four commercially available protein hydrolysate mixtures and a synthetic peptide, when added to the LAS solution, countered this to varying degrees, from the epidermis being as distorted as the LAS control to as flat as the water control. A study to determine the contribution of these materials’ positive charge (isoionic point) to in vitro epidermis flatness demonstrated a direct linear relationship, i.e., the more positive the charge the flatter the epidermis. This effect was even discernible in a 1 to 30 ratio of a highly cationic protein to detergent. One of the protein mixtures, which was then fractionated according to charge, showed a linear regression correlation coefficient of 0.86 for this relationship. Because the twisting and curling of epidermis has been demonstrated to be related to human skin irritation, these results suggest that positively charged proteins might increase the mildness of solutions containing anionic detergents.
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