Shozo Koga

Physical Properties of Cell Water in Partially Dried Saccharomyces cerevisiae

The equilibrium vapor pressure, the heat of vaporization, the dielectric increment, and the NMR spectra of partially dried cells were studied in Saccharomyces cerevisiae with water contents varying in the range from 25 to 0.8%. The comparative study of those physical properties suggests that physical states of the microbe can be classified into four regions in accordance with the states of the cell water: the solution region, the gel region, the mobile adsorption region, and the localized water region. Much difference in the physiological properties is found between the cells in the solution region and those in the gel region, whereas the pattern changes in physical properties take place when the cells in the gel region are dried to a further extent into the mobile or the localized region. The various modes in the molecular motion of the cell water reflected in those physical properties of the cell seem to give some insight into the biological functions of the molecule in the native as well as the dried states of the cell.

Thermal analysis of bacteriophage T4

Abstract The process of bacteriophage T4 morphogenesis was studied using a heat leakage scanning calorimeter. Thermograms of defective mutant 49 (am NG727) in permissive and non-permissive cells of Escherichia coli showed a difference in thermal properties between packaged and non-packaged DNA molecules. In vivo , non-packaged DNA carried out their thermal transition at 85°C, the same temperature as that of T4 DNA melting measured in the standard saline citrate buffer, while the packaged DNA gave a sharper peak at 87°C due to some interaction with the head shell structure. Empty head shells showed a sharp heat absorption peak at 89°C both in vivo and in vitro , indicating the high degree of cooperativity in their conformational changes.

Role of the gene 17 protein of bacteriophage T4.

Head-related particles of bacteriophage T4 were examined by using heat leakage scanning calorimetry. The 17- particles showed two endothermic peaks on thermograms during their thermal transition process, while 49- particles gave only a single sharp endothermic peak. Thermograms of 17- particles treated with 23- defective lysate were different from those of nontreated 17- particles, and closely resembled thermograms of 49- particles. The 31- defective lysate was also capable of converting thermal properties of 17- particles. These results suggest that there is a structural difference between 17- particles and 49- particles, and that the product gene 17 of bacteriophage T4 is involved in the structural conversion of prohead to a more completed structure.

Proton conduction in phosphatidylethanolamine.

The dc conductivity of polycrystalline phosphatidylethanolamine (PE) was measured in the temperature range 60-120 degrees C. Since no conclusive evidence had so far been obtained for the presence of proteon conduction in this phospholipid, hydrogen gas was shown in the present experiment to evolve during the electrolysis in its premelted state between 91 and 124 degrees C. In this temperature range molecules assume rotation around the molecular axes and proton conduction of the Grotthus type takes place possibly along two chains of intermolecular hydrogen bonds running in parallel. Zwitter-ions behave cooperatively as proton donors and acceptors in transferring proton from molecule and molecule via the hydrogen bond networks. This efficient push-pull way of proton transferring seems to account for the fact that no polarization was observed in the dc conduction experiments. The amount of devolved gas appears to be not exactly in accordance with Faradays law and discussions are made on possible causes for this slight deviation.