Effect of Alcohols on Escherichia coli Phages.

Abstract

Escherichia coli T even phages were ethanol sensitive, whereas T odd phages were ethanol tolerant. The phagecidal activities of alcohols on ethanol sensitive phages (T even, X) were revealed to be in the order n-propanol > ethanol > methanol >> n-butanol >> n-hexanol >> noctanol. However, the those of alcohols on ethanol tolerant phages (T odd) were revealed to be in the order methanol>ethanol>n-propanol. The phagecidal activity of n-butanol (hydrophobic) increased when small amounts of hydrophilic methanol (10 and 20%, v/v), ethanol (10 and 20%, v/v) were added. The relative soluvbility curves of glucose plus Sudan III (hydrophobicity-hydrophilicity indication) were similar to the X phagecidal activity curves of ethanol solution. The denaturation of ethanol-sensitive phage proteins with ethanol solution (50 or 70%, v/v) on SDS-polyacrylamide gel electrophoresis was associated with a loss of the plaque-forming activity of the phage. These phenomena were not observed for the ethanoltolerant phages treated with ethanol solutions. The head proteins of ethanol-tolerant phage have a greater number of hydrophobic amino acids and fewer hydrophilic amino acids , whereas those of ethanol sensitive phage have a greater number of hydrophilic amino acids and fewer hydrophobic amino acids. From these data, we suggest that the hydrophobicityhydrophilicity balance of the alcohol solution and the phage surface proteins affects the loss of the plaque-forming activity of E. coli phages by alcohol.

Relationship Between Bactericidal Activity and the Hydrophobicity-Hydrophilicity Balance of Alcohol Solutions.

“…We have reported that Escherichia coli phages are more tolerant to alcohol than bacteria (Yamashita et al, 2000). We further found that the inactivation activity of ethanol on phages was the highest at a concentration range of 60-70% (v/v) and that the activity of the ethanol treatment in this range was not affected by temperature.The hydrophobicity -hydrophilicity balance of the alcohol solution also affected the phage-inactivation activity.…”

Morphological Changes in Escherichia coli Phages Treated with Ethanol.

“…The amino acid composition of the tail sheath protein of the T-4 phage of Arisaka was not hydrophilic. In our data, the tail sheath proteins of ES1 and ES 2 phages treated with 30% (v/v) ethanol exhibited no denaturation by SDS-PAGE (Yamashita et al ., 2000) . It was reported that the contracted tail sheath could be prepared by heat treatment at 55°C for 5 min (Yamamoto and Uchida, 1973) .…”

“…In our previous work (Yamashita et al, 2000) , we reported that the T-even phages of E. coli were ethanol-sensitive, whereas the T-odd phages were ethanol-tolerant. Moreover, the extensive denaturation of the ethanol-sensitive phage proteins after treatment with ethanol solution (50 or 70%, v/v) by SDS polyacrylamide gel electrophoresis (PAGE) , was associated with the loss of the plaque-forming activity of these phages.…”

“…The materials and methods used for the experiments were the same as those in our previous study (Yamashita et al, 2000) . The phage stocks used for the electron-microscopic observation of negatively stained phages were prepared according to the methods of Childs and Birnboim (1975) and Dyson and Van Holde (1967) .…”

“…Arrows indicate the contracted tail sheath . Bar,100nm. hydrophobic balance of the amino acids of phage head proteins in ethanol sensitive-phages indicates hydrophilicity whereas that in ethanol-tolerant phages indicates hydrophobicity (Yamashita et al, 2000) . Arisaka et al (1988) reported the amino acid composition of the tail sheath protein of the T-4 phage.…”