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Asada R, Yamada Y, Sakamoto JJ, Furuta M, Tsuchido T. Theory and application of growth delay analysis of colony formation for evaluation of injured population of the stressed fungal conidia. JOURNAL OF MICROORGANISM CONTROL 2023; 28:93-100. [PMID: 37866901 DOI: 10.4265/jmc.28.3_93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
A new concept of injured population assessment is proposed, in which the size of the injured population in stressed mold spores is evaluated by analyzing the colony formation process on a solid agar medium. In this method, a small paper disc containing mold spores is placed on a subculture agar plate, and the linear increase in the radius of the colony formed by development from the spore is measured over time. Then, the principle of the previously reported growth delay analysis (GDA) method originally using a liquid medium is applied to obtain the integrated viable ratio (IV) of the stressed population from the delay time relative to the growth of the unstressed population. On the other hand, the viable ratio (V) to the initial value as the colony count obtained with the stressed culture is obtained; the difference between the logarithms of V and IV is determined as the log number of the injured population. Applying this analysis method to heated spores of Cladosporium sphaerospermum, we determined the size of the injured population that occurred. This method was considered to be effective as a new method for quantifying injured populations using a solid medium.
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Affiliation(s)
- Ryoko Asada
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University
| | - Yoshie Yamada
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University
| | - Jin J Sakamoto
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University
- MPES-3U and Faculty of Materials, Chemistry and Biotechnology, Kansai University
| | - Masakazu Furuta
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University
| | - Tetsuaki Tsuchido
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University
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Vo KC, Wada A, Iwata R, Asada R, Sakamoto JJ, Furuta M, Tsuchido T. Evaluation of distinct modes of oxidative secondary injury generated in heat-treated cells of Escherichia coli with solid/liquid and complex/semi-synthetic media sets. J Appl Microbiol 2022; 133:2361-2374. [PMID: 35771133 DOI: 10.1111/jam.15697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 05/26/2022] [Accepted: 06/27/2022] [Indexed: 11/28/2022]
Abstract
AIMS To characterize and evaluate oxidative secondary injury generated in heat-treated Escherichia coli cells during recovery cultivation either on agar or in a broth of a semi-synthetic enriched M9 (EM9) medium and a complex Luria broth (LB) medium with different types of antioxidants. METHODS AND RESULTS E. coli cells grown in the EM9 and LB broth were heated at 50o C in a buffer (pH7.0). Heated cells were recovered on the same kind of agar medium as that used for growth, with or without different antioxidants. Although these antioxidants mostly protected the cells from oxidative secondary injury on the recovery media, sodium thiosulfate and sodium pyruvate were most protective on EM9 and LB agars, respectively. Determination of viability using the most probable number and growth delay analysis methods showed significant reductions in the protective effects of antioxidants in the EM9 and LB media. CONCLUSION Oxidative secondary injury generated in heated E. coli cells was found to be qualitatively and quantitatively diverse under cellular and environmental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY Our results suggest that different modes of oxidation should be considered in viability determination and injured cell enumeration of heat-treated cells.
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Affiliation(s)
- K C Vo
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
| | - A Wada
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
| | - R Iwata
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
| | - R Asada
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan.,Radiation Research Center, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan.,Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
| | - J J Sakamoto
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan.,Faculty of Materials, Chemistry, Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka, Japan
| | - M Furuta
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan.,Radiation Research Center, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan.,Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
| | - T Tsuchido
- Research Center of Microorganism Control, Organization for Research Promotion, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Japan
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