Biocontrol Science
Online ISSN : 1884-0205
Print ISSN : 1342-4815
ISSN-L : 1342-4815
14 巻 , 1 号
選択された号の論文の6件中1~6を表示しています
Original papers
  • TOYOTOSHI UEDA, MASANORI HARA, IKUMI ODAGAWA, TAKANORI SHIGIHARA
    2009 年 14 巻 1 号 p. 1-12
    発行日: 2009年
    公開日: 2009/10/27
    ジャーナル フリー
    A new type of ultrasonic washer-disinfector-sterilizer, able to clean, disinfect and sterilize most kinds of reusable medical devices, has been developed by using the ultrasonic levitation function with umbrella-shape oscillators and ozone bubbling together with sterilization carried out by silver electrolysis. We have examined the biomedical and physicochemical performance of this instrument. Prokariotic and gram-negative Escherichia coli and eukariotic Saccharomyces cerevisiae were killed by silver electrolysis in 18 min and 1 min, respectively. Prokariotic and gram-positive Geobacillus stearothermophilus and Bacillus atrophaeus, which are most resistant to autoclave and gas sterilization, respectively, were killed by silver electrolysis within 20 min. Prokariotic and gram-negative Pseudomonas aeruginosa was also killed by silver electrolysis in 10 min. The intensity distribution of the ultrasonic levitation waves was homogeneous throughout the tank. The concentration of ozone gas was 2.57 mg/ kg. The concentration of dissolved silver ions was around 0.17 mg/L. The disulfide bond in proteins was confirmed to be destroyed by silver electrolysis.
  • AKIHIRO SHIRAI, TOMOKO SUMITOMO, MAYUKO KURIMOTO, HIDEAKI MASEDA, HIRO ...
    2009 年 14 巻 1 号 p. 13-20
    発行日: 2009年
    公開日: 2009/10/27
    ジャーナル フリー
    The gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'-(2,7-dioxaoctane)bis(1-decylpyridinium bromide) (3DOBP-4,10), exerted fungicidal activity against Saccharomyces cerevisiae accompanied by respiration inhibition and the cytoplasmic material leakage of ATP, magnesium, and potassium ions. We previously found that gemini-QUAT exerted bacterioclastic action against Escherichia coli by causing the rapid and abundant leakage of turbid materials from the cells. In addition, the first stage of the bacterioclastic action was the leakage of magnesium ions, outer membrane protein E, ATP, and lipopolysaccharides. Here, we investigated how the gemini-QUAT 3DOBP-4,10 exerts fungicidal action against S. cerevisiae. The results showed that that ≥ 0.4 μM 3DOBP-4,10 stopped respiration and that ≥ 3.0, 1.0 and 1.0 μM caused the leakage of cytoplasmic components ATP, magnesium and potassium ions, respectively. Scanning and transmission electron micrographs showed a preserved cell wall structure, whereas intracellular organelles were destroyed in cells incubated with 3DOBP-4,10. We postulated that 3DOBP-4,10 exerts its fungicidal action against S. cerevisiae not through cell wall destruction and protein leakage, but rather by penetrating the cell wall and disrupting the membranes of organelles.
  • KAZUHIDE ITO, YU MIZUNO
    2009 年 14 巻 1 号 p. 21-30
    発行日: 2009年
    公開日: 2009/10/27
    ジャーナル フリー
    The objective of this study was to develop a numerical, reaction-diffusion based model that predicted colony formation by taking into account the influence of nutrients, moisture (water activity), temperature, and the surface characteristics of building materials for various fungi. First, the results of fundamental experiments that measure the growth responses of colony size on culture media under various environmental conditions are presented. Second, the mathematical models that reproduce colony formation on the PDA medium and the numerical simulation intended for the experimental conditions are discussed. Fitting of the model coefficients was performed using the data of the fundamental experiments, and sensitivity analysis was executed. The mathematical models proposed depended on the nutrient concentration and the substrate softness of the surface of the construction materials, and were in reasonable agreement with the experimental data.
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Communication
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