자료유형 | 학위논문 |
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서명/저자사항 | Illuminating Dark Matter: Light Microscopy and Raman Microspectroscopy Through Transparent Porous Media for Applications in Soil and Sediment Microbial Ecology. |
개인저자 | Sharma, Kriti. |
단체저자명 | The University of North Carolina at Chapel Hill. Biology. |
발행사항 | [S.l.]: The University of North Carolina at Chapel Hill., 2019. |
발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
형태사항 | 167 p. |
기본자료 저록 | Dissertations Abstracts International 81-05B. Dissertation Abstract International |
ISBN | 9781088353462 |
학위논문주기 | Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2019. |
일반주기 |
Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
Advisor: Shank, Elizabeth A. |
이용제한사항 | This item must not be sold to any third party vendors. |
요약 | Soils offer habitats to an unparalleled abundance and diversity of microorganisms, whose activities are critical to agriculture, ecosystem health, and biogeochemical cycling. A major barrier to understanding soil microbes within their habitats is the opacity of natural soils. Despite a long history of endeavors to visualize life in the soil, and promising advancements in this field, non-destructive approaches that allow dynamic insights into microbial life in soils are particularly lacking. Chapter 1 reviews this field and outlines the history and potential of optically transparent porous media as model soil systems amenable to non-destructive imaging of soil microorganisms within three-dimensional soil-like matrices.In Chapter 2, I introduce the utility of single-cell Raman spectroscopy (SCRS) for non-destructive stable isotope probing over time, particularly for monitoring the uptake of 13C by bacteria from complex natural polysaccharides. This spatially resolved and non-destructive approach allows us to ask the question, "Do bacterial biofilms allow bacteria to stick together in numbers large enough to initiate cooperative decomposition of necromass?'In Chapter 3, I assess the polymer Nafion and the crystal cryolite as substrates for optically transparent model soil systems called "transparent soil" (TS) microcosms. I find that both substrates are compatible with optical microscopy and enable growth, maintenance, and visualization of micron-sized bacteria in three-dimensional porous matrices over time. Both substrates are also compatible with SCRS, and enable stable isotope probing (SIP) using deuterium (D2O) as a non-destructive marker of microbial activity in situ, while cryolite-based microcosms also enable measurement of 13C label uptake in bacteria. I use D2O label tracing to show that bacterial cells attached to dead fungal hyphae within a Nafion matrix show more metabolic activity after a dry-wet cycle than cells far away from the fungal hyphae, corroborating the important role of fungi in facilitating survival of bacteria in the fluctuating conditions found in soils.In Chapter 4, I present a method for rapid and inexpensive manufacture of microfluidics devices that were used to construct TS microcosms at the lab bench. Chapter 5 summarizes the dissertation overall and offers suggestions for future research. |
일반주제명 | Microbiology. Ecology. Soil sciences. |
언어 | 영어 |
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