Jiro Takano

Photoreaction of Cholesteryl trans-Cinnamate in Mesomorphic States

Abstract The photoreaction of cholesteryl trans-cinnamate in K Br matrix was studied in the solid, mesomorphic and isotropic liquid states at 25−225°C, and compared with the solution reaction in n-hexane. Cholesteryl trans-cinnamate was converted into a dimer on irradiation at wave-length longer than 300 nm at these phases. The photoirradiation in the solution led to a cis-isomer at 25−30°C. The initial rate of the dimerization at the mesophase was found to be higher than that at the isotropic liquid phase. The photoreaction in the solid took place at a much slower rate than in the other states. These suggest that some kinds of ordering besides the mobility of the molecules of the cinnamate enhance the rate and affect the course of the reaction on irradiation in comparison with the reaction in the isotropic solution.

Differences in the surface membranes and water content between the vegetative cells and spores of Bacillus subtilis

Bacillus subtilis forms both vegetative cells and spores. The fluidity of the membranes in these forms was measured by using fluorescent anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH). The spores were more rigid than the vegetative cells, suggesting that the structure of the spores and vegetative cells was different. This difference was thought to be due to the structure of the cell membranes. The anisotrophy of DPH in the cell membranes of spores gave higher values at all temperatures. The anisotrophy of DPH in the cell membranes of vegetative cells was lower than that of the spores and the value depended upon the temperature. Time Domain Reflectometry (TDR) was used to measure the quantities of bound and free water in the vegetative cells and spores. The spores were dehydrated, and the amount of bound and free water in the spores was about two‐thirds of the levels in the vegetative cells. The spores have fewer sugars molecules on their cell surface membranes, but contained as much sugars within the cell. Almost 100 per cent of the vegetative cells wee absorbed toward chitin, but the spores were not absorbed toward it at all. It was felt that the surface membrane of the vegetative cell had a high mobility because it was sugar‐rich, while the surface membrane of the spore showed a lower mobility because there are fewer sugars on the outer membrane. The spores survive in high temperatures because the surface membrane of the spore is tight and has relatively few sugars. Dehydration causes the rigidity of the spores. On the other hand, the vegetative cells are sugar‐ and water‐rich, which makes them more fluid. The difference between the vegetative cells and spores is the glycosylation of their surface membranes. Copyright

Determination of the water necessary for survival of Bacillus subtilis vegetative cells and spores

Abstract To determine the minimal amount of water necessary for survival in Bacillus subtilis, bound and free water were measured by time domain reflectometry (TDR) and the gel—sol phase transition of bound water was measured by differential thermal analysis—thermogravimetry (DTA—TG). Both the vegetative and the spore form of Bacillus subtilis were dried at different temperatures. From the measurements, the relationship between survival of the bacteria and water can be summarized as follows. (1) The vegetative form of bacteria was still 100% viable even when 80% of bound water was removed. (2) The spore form contained only 20% of bound water, which was easily and quickly removed by drying, and resulted in loss of viability. (3) Phase transition between gel and sol phases of bound water occurred repeatedly in the dried vegetative 100%-viable bacteria, which still had 20% bound water. The bacteria were still viable after such measurements. (4) In the spore form, phase transition was not detected.

Illustrations of the value of calorimetry in biology

Calorimetry was used to measure heat generated by both living microorganisms and macroorganisms. This seemingly simple measurement can give an evaluation of the state of an organism and can differentiate between rest, sleep, under anaesthesia, activity and inactivity. The great advantage of calorimetry is that the measurement is not harmful and does not cause any damaging effect on the samples.

Capillary method of gas sampling under constant flow rate for the measurement of time average concentration of hydrocarbons in the atmosphere.

キャピラリーを利用した大気成分の分析のための新しいサンプリング法を開発した.この装置では,キャピラリーの一方を大気に開放し,他方を真空容器に接続するが,真空容器の圧力が0から0.3気圧に増大するまでの範囲では,圧力に関係なく流量はほぼ一定であり,0.3気圧以上真空系の圧力が高くなると,キャピラリーの長さや内径に関係なく流量が減少することを確認した。この性質を利用して,内圧が0から0.3気圧にまで増大する範囲でキャピラリーを通して大気のサンプリソグを行えば採取した容器内の試料濃度はサンプリング期間中の一定流量下での時間平均値が得られる.このことを確かめるために炭化水素を用いて一定時間ごとにその濃度を変化させて採取した試料の時間平均濃度を測定したところ,計算値と一致することを確認した.本サンプリング法は炭化水素の時間平均濃度の分析に適用できることを確認した.本法は大気中炭化水素,労働作業環境の有機化合物などの時間平均濃度を測定するためのサンプリング法として有用であることが推定された.