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Full text release has been delayed at the author's request until August 07, 2026

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Investigating sonoporation in cyanobacteria exposed to ultrasound

Thayer, Shannon R
http://orcid.org/0009-0004-4145-1366
http://rave.ohiolink.edu/etdc/view?acc_num=osu1689881363727716

Abstract Details

2023, Master of Science, Ohio State University, Environmental Science.
Cyanobacteria harmful algae blooms are an issue of increasing concern, especially in source water that is used for drinking water. Several treatment technologies have been proposed for mitigating these blooms. Low power ultrasonic units are used as a treatment technology for treating and decreasing blooms in source water. Currently, there lacks an understanding of how cyanobacteria interacts with low power ultrasonic units and the mechanism of treatment, if there is one. The goal of this work aimed to discern how cyanobacteria cells may be impacted by low power ultrasonic units. We examined a specific mechanism of interaction, called sonoporation. We employed cell stains, a flat plate ultrasonic transducer, an anechoic chamber, and flow cytometry to elucidate if sonoporation was occurring in these instances. The study considered Microcystis sp. and Anabaena sp., which are a unicellular and filamentous type of cyanobacteria, respectively. Our first objective was to develop a cell staining technique that could be used to study sonoporation in cyanobacteria using flow cytometry. Our goal was to be able to assess increased permeabilization of samples. Cyanobacteria exhibit natural fluorescence which can interfere with the fluorescence emitted by certain cell stains. The specific cell stains used for our work were cell permeant and cell impermeant. Cell permeant stains enter into all cells in a population while impermeant stains only enter into cells with a damaged membrane, or if the membrane were transiently permeable, such as is the case with sonoporation. Previous studies have not used combinations of cell permeant and cell impermeant stains compatible with natural cyanobacteria fluorescence to detect viability over long term experiments using flow cytometry. Five different sets of cell permeant and cell permeant stains were tested with Microcystis sp. We found that the cell permeant stain DAPI and the cell impermeant stain SYTOX Green worked for examining Microcystis sp. cultures flow cytometry. Anabaena sp. cultures were more difficult to work with and were examined using only SYTOX Green to see increases in permeabilized cells. Our second objective evaluated the potential for sonoporation using a flat plate ultrasonic transducer. A frequency of 1055 kHz and a power setting of 75 W were used consistent with settings used in previous work demonstrating sonoporation for drug delivery in human cells. In this study, Microcystis sp. samples were exposed to ultrasound for 10 minutes. Flat plate control experiments showed an exponential increase in the number of cells stained with SYTOX Green over 5 minutes and reached a plateau of approximately 70% by 10 minutes of ultrasonic exposure. Results indicated that sonoporation and/or cell lysis was occurring as more SYTOX Green stain was able to enter into cells due to ultrasonic exposure. The percent of SYTOX Green entering cells out of the total population increased significantly with time (p  0.0001). Our final objective was to test cyanobacteria cells exposed to a commercially available low power ultrasonic field unit. An anechoic chamber was created with acoustic tiles to prevent reflection of sound waves from the sides of the tank. This anechoic chamber simulated ultrasonic exposure in a field deployment. A low power ultrasonic field unit was suspended in the chamber. Samples of Microcystis sp. and Anabaena sp. had cell stains added, were put in closed containers, and were attached to a rotating sample holder which submerged samples in the anechoic chamber. Samples were then exposed to four or eight full cycles of ultrasound exposure from the ultrasonic field unit. The percent of cells permeabilized (e.g., those with transient or permanent cell membrane permeability) was then examined using flow cytometry. There was variance seen across experimental conditions, including ultrasound exposed and unexposed controls and between days experiments were performed. However, results from ANOVA analysis showed that the variability in the data could not be explained by the factor of ultrasound exposure. We deduced that most of the variability seen was due other factors such as working with biological samples across the time span of three weeks. Overall, there was no significant difference between ultrasound exposed and control samples for both Anabaena sp. and Microcystis sp. These results indicate that sonoporation did not occur for either organism when exposed to a low power ultrasonic field unit.
Linda Weavers (Advisor)
Natalie Hull (Committee Member)
Allison MacKay (Committee Member)
354 p.
Engineering
Ultrasound; sonoporation; cyanobacteria; source water treatment

Recommended Citations

Citations

  • Thayer, S. R. (2023). Investigating sonoporation in cyanobacteria exposed to ultrasound [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1689881363727716

    APA Style (7th edition)

  • Thayer, Shannon. Investigating sonoporation in cyanobacteria exposed to ultrasound. 2023. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1689881363727716.

    MLA Style (8th edition)

  • Thayer, Shannon. "Investigating sonoporation in cyanobacteria exposed to ultrasound." Master's thesis, Ohio State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=osu1689881363727716

    Chicago Manual of Style (17th edition)

osu1689881363727716
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This open access ETD is published by The Ohio State University and OhioLINK.