Biocontrol Science
Online ISSN : 1884-0205
Print ISSN : 1342-4815
ISSN-L : 1342-4815
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  • MD. TOUHIDUL ISLAM
    2022 Volume 27 Issue 4 Pages 185-191
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    The fungal biocontrol agents, Cladosporium sp. have great economic importance on account of their beneficial effects on the integrated pest management (IPM) program. The different species of this genus can control different arthropod pests like sweetpotato whitefly, sugarcane woolly aphid, two-spotted mite, cotton aphid, cotton leaf worm, red spider mite, armyworm; and different plant diseases like- rice blast, wheat stripe rust, chrysanthemum white rust, etc. Chemical pesticides are a common practice by the user to protect their crops from these pests. But the intensive use of chemical pesticides has harmful impacts on human health and ecosystem functioning, and they also reduce plant protection sustainability. Sustainable plant protection could be achieved through the reduction of chemical pesticides, resulting in minimal impact on the environment without compromising crop yields. This review was written based on biocontrol methods using Cladosporium sp. which is an alternative option for pest management. Continued research concerning the commercialization of these biocontrol agents as biopesticides may contribute to sustainable plant protection.

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  • TORU IYO, KEISUKE IWAHORI
    2022 Volume 27 Issue 4 Pages 193-200
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    Electrolyzed water is a novel disinfectant that is widely used in the food industry. We conducted an experimental model-based study to determine the effectiveness of neutral electrolyzed water (NEW) for the daily nozzle cleaning of artificially contaminated tankless and tank-type bidet toilet seats. The toilet seats were designed to automatically self-clean the spray nozzles using tap water or NEW after each use or at specified intervals. The numbers of Pseudomonas aeruginosa and Escherichia coli microorganisms in the spray water were measured twice or thrice per week. A Kruskal-Wallis test was used to compare the bacterial count in the spray water of various cleaning (NEW) and control (tap water) conditions. The number of bacteria was significantly lower in NEW conditions with and without periodic nozzle cleaning functions than in tap water conditions for both tank-type and tankless bidet toilet seats. Microorganisms were detected only on the surface area around the opening for ejecting spray water and not in the internal piping at the spray nozzle tip. These findings demonstrate that NEW has superior decontamination efficacy over tap water when used as a cleaning agent for the spray nozzles of warm-water bidet toilet seats.

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  • FATEMEH RAFIEE, MOHAMMAD REZA FAZELI, ABBAS AKHAVAN SEPAHI, ZAHRA NOOR ...
    2022 Volume 27 Issue 4 Pages 201-208
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    The genus Fusarium causes a wide range of infections in human, animals and herbs. The purpose of this research was to investigate and identify the native strains of Bacillus subtilis playing an inhibitory role against Fusarium oxysporum by producing surfactin. B. subtilis was isolated from the soil of various parks in Tehran-Iran, and identified by biochemical tests. Growth inhibition zone, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of B. subtilis were determined. After purification of surfactin, quantitative and qualitative analysis of surfactin conducted using high performance liquid chromatography (HPLC) . Finally, two selected native strains with the highest production rate of surfactin identified using PCR for 16S rRNA and phylogenetic tree was drawn. Sixty strains of B. subtilis were isolated from soil, after identification through phenotypical and biochemical tests, the antagonistic activity of 27 different strains against F. oxysporum by Agar well diffusion assay determined and the highest inhibition zone was 13.66 mm. Six strains showing the best inhibitory effect, were isolated and their metabolite were purified by methanol. MIC and MFC values of different strains were in the range of 0.5-1.6 and 1.6-2.6 mg/mL. Using HPLC, the purified surfactin content in B. subtilis was about 56.7 – 131.9 μg/mL. Based on the curves of the chromatogram, the preferred strains with the highest production of surfactin, by molecular identification, displayed high similarity to B. subtilis. We got a maximum amount of yellow and transparent surfactin from native strains. Furthermore, the selected bacteria can be good candidates for biological control of fungal pathogens.

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  • MASAHIKO OKAI, RINTARO ENDO, MASACHIKA TAKASHIO, MASAMI ISHIDA, NAOTO ...
    2022 Volume 27 Issue 4 Pages 209-215
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    Extended-spectrum β-lactamases (ESBLs) are produced mainly by gram-negative bacteria in Enterobacteriaceae. One of the major types of ESBLs is sulfhydryl variable (SHV) -type ESBL. Herein, we attempted to develop a simple and rapid method for the detection of the ESBL blaSHV gene by loop-mediated isothermal amplification (LAMP) . The five-primer set designed could amplify blaSHV gene at an isothermal temperature of 65℃. The detection limit of the LAMP method with the LF loop primer was 1 copy/tube, which was 10,000-fold more sensitive than that of the conventional PCR. The LAMP assay could also detect the direct amplification of blaSHV gene from a single river water sample in Tokyo. The LAMP method has great potential for applications in hospital, soil and water environment, food, and livestock.

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  • RETSUO KAWAKAMI, YUKI TAKAO, AKIHIRO SHIRAI, TAKASHI MUKAI
    2022 Volume 27 Issue 4 Pages 217-222
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    The remote bactericidal effect of TiO2 photocatalyst, i.e., the bactericidal effect away from the photocatalyst, was successfully achieved using a humidified airflow. The TiO2 photocatalyst used was anatase-type TiO2 nanoparticles (NPs) annealed with a low-temperature O2 plasma. For comparison, anatase-type TiO2 NPs annealed in the air were used. The bacteria, Bacillus subtilis, were placed away from the TiO2 NPs. The plasma-assisted-annealed TiO2 NPs significantly inactivated 99% of the bacterial cells in 5 h, whereas the pristine and air-annealed TiO2 NPs inactivated 88-90% of the bacterial cells. The remote bactericidal effect of plasmaassisted-annealed TiO2 NPs would be attributed to a larger amount of H2O2 molecules traveled by the airflow from the TiO2 NPs. The molecules were generated by chemically reacting more photoexcited carriers on the TiO2 surface with H2O and O2 in the airflow. These photoexcited carriers originated from more oxygen-based species adsorbed and more oxygen vacancies introduced on the TiO2 surface by the plasma-assisted-annealing.

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  • YU HARADA, HITOMI AMO, TAKUTO ONO, HIROKI MURAI, TADAHIRO SASAKI, TATS ...
    2022 Volume 27 Issue 4 Pages 223-228
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major burden for health care systems worldwide, and is a threat to our daily lives. Various effective ingredients against SARS-CoV-2 were already reported, however, since products contain various ingredients, it is also important to evaluate the effectiveness of commercially available disinfectants per se. In this study, the virucidal efficacy of forty-eight commercially available products were evaluated according to the standardized suspension method EN 14476 and the following results were obtained: Alcohol-based disinfectants, hand soaps, wet wipes, alkaline cleaners, quaternary ammonium compound sanitizers and oxygen bleach had great virucidal efficacy against SARS-CoV-2. Enveloped viruses such as SARS-CoV-2 are among the most susceptible of pathogens to formulated microbicidal actives and detergents, but as the results of this study showed, it is also necessary to pay attention to the concentration at the time of use and the required contact time.

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  • AKARI WATANABE, NAOFUMI TAMAKI, KENJI YOKOTA, SUSUMU KOKEGUCHI, HIRO-O ...
    2022 Volume 27 Issue 4 Pages 229-233
    Published: 2022
    Released on J-STAGE: December 25, 2022
    JOURNAL FREE ACCESS

    The statistical correlation between the number of oral streptococci and the results of ATP bioluminescence assay was examined and compared with the results from Streptococcus plate counts and an oral bacteria quantification system. Because a significant correlation was found between ATP (RLU) and the number of bacteria in the oral bacteria quantification system for all seven types of oral streptococci examined, ATP would reflect a conditions of oral hygiene. However, using this assay, it was observed it may be difficult to correctly evaluate bacteria that form aggregates. Furthermore, even a small number of bacteria (below 105 CFU/mL) , which cannot be measured by the oral bacteria quantification system, could be estimated by using ATP bioluminescence assay. It was suggested that this assay could be used for quantitative evaluation of the effect of oral cleaning.

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