자료유형  

 학위논문

Control Number  

0016935248

International Standard Book Number  

9798380725521

Dewey Decimal Classification Number  

545

Main Entry-Personal Name  

Noll, Sarah Elizabeth.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2021

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2021

Physical Description  

1 online resource(257 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

General Note  

Advisor: Zare, Richard;Dai, Hongjie;Moerner, William;Bent, Stacey F.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2021.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Mass spectrometry is a powerful technique for the study of biological systems because it enables untargeted analysis of endogenous molecules, giving us insight into metabolism and signaling. Here we focus on ambient ionization methods for sampling, specifically desorption electrospray ionization imaging (DESI-MSI) and the liquid micro-junction surface-sampling probe (LMJ-SSP).A recurrent theme of the described work was the adaptation of DESI-MSI for the imaging of small tissues, in particular murine adrenal glands under 2 mm in diameter and maize root primary tips under 1 mm in diameter. We discuss the elements of probe construction, set-up, and image acquisition that influence the quality of measured DESI images. This contextualizes the modifications to the DESI probe and method that were made in order to resolve fine sub-tissue regions in these small tissues. The lateral spatial resolutions were also retroactively calculated for all imaged tissue sets in order to assess the influence of probe, step size, and sample material on resolution.We then apply DESI-MSI to the imaging of maize root cryosections, demonstrating this technique's potential for identifying small molecule regulators of development. Plant roots are uniquely suited to the study of growth, because one tissue section contains cells in multiple stages of development along its longitudinal axis. DESI imaging reveals not only metabolite gradients along this developmental axis, but also unique spatial patterning that correlates to known tissue sub-structures, including the inner vasculature and endodermis. Observed variations in the abundance of TCA cycle metabolites along growth zones motivated exogenous treatments, with resulting phenotypic changes providing insight into developmental regulation.Shifting from the plant to the animal kingdom, we use DESI-MSI to explore the metabolic and lipidomic alternations associated with specific causative genotypic variants of pheochromocytomas and paragangliomas (PPGLs). This project focused on the development of a mouse model for succinate dehydrogenase (SDHx)-deficient PPGLs in order to explore the driving factors for tumorigenesis, which the current model ascribes to elevated succinate. Genetic knockouts were targeted to the murine adrenal medulla, the origin of pheochromocytomas. Loss of Sdhb alone did not produce tumors, but loss of both Sdhb and Nf1, a gene frequently mutated in PPGLs, did produce tumors. Because the adrenal gland is comprised of two distinct sub-tissues, the cortex and the medulla, DESI-MSI was key to verifying the spatially restricted metabolic changes resulting from each genetic knockout. Medulla-specific succinate accumulation was observed in all Sdhb-deficient tissues, but not in tissues with loss of only Nf1. Elevated succinate, alone, was not found to be sufficient for tumorigenesis in the mouse, but additional features of SDHx tumors are explored in each model. DESI-MSI correlated observed changes in murine models to those in human biopsies of SDHx PPGLs. Catecholamines were also mapped within the medulla to demonstrate further this technique's capability to resolve fine distribution patterns in small tissues regions.We also describe an exploration of live cell measurements by mass spectrometry, undertaken early in the PhD. Such measurements require cell- and mass spectrometry-compatible buffer and isolation of the sample from any applied spray potential or co-spray solutions. An LMJ-SSP was used as the basis for the designed sampling procedure, because it is compatible with liquid samples, allows for perfusion of a potential ligand solution, and can easily be lowered into a culture well. Two subsequent iterations of probe design are described in order to accommodate an organic/acidic co-spray solution in a manner isolated from the sample surface. Additional applications of the designed co-axial probe are discussed.

Subject Added Entry-Topical Term  

Mass spectrometry.

Subject Added Entry-Topical Term  

Tumorigenesis.

Subject Added Entry-Topical Term  

Dopamine.

Subject Added Entry-Topical Term  

Solvents.

Subject Added Entry-Topical Term  

Microscopy.

Subject Added Entry-Topical Term  

Biopsy.

Subject Added Entry-Topical Term  

Adrenal glands.

Subject Added Entry-Topical Term  

Scientific imaging.

Subject Added Entry-Topical Term  

Lipids.

Subject Added Entry-Topical Term  

Tumors.

Subject Added Entry-Topical Term  

Metabolites.

Subject Added Entry-Topical Term  

Catecholamines.

Subject Added Entry-Topical Term  

Analytical chemistry.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 85-05B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:639092