Life Sciences Commons^™

Unseen Science: Modern Discoveries Too Far Away Or Tiny For Human Eyes, Lucy Huang

Capstones

As science has progressed, scientists have realized that evidence goes beyond the realms of physical sight. Whether it is too small or difficult to find, scientists have developed different ways to get around this problem. We see this in cancer genomics and in extrasolar planetary research. Scientists use what they know and what they measure to validate their work.

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Lim Protein Ajuba Directly Interacts With Replication Protein A To Prevent Atr Dna Damage Response, Sandy Wan Shan Fowler

Dissertations, Theses, and Capstone Projects

Integrity of the human genome is essential for viability and proliferation of human cells. Intrinsic (endogenous replication stress) or extrinsic (UV, chemotherapy drugs) agents threaten the stability of the genome by generation of single stranded (ss) DNA or double stranded (ds) DNA breaks. The DNA damage response (DDR) pathways are conserved in evolution and constitute systems that perform the surveillance, signaling, and repair of the damage in the nucleus. Unchecked and accumulation of DNA damage can lead to deleterious effects such as replication fork collapse, chromosome fusion and breakage. The dysregulations of DNA damage response pathways are hallmarks of tumorigenesis. …

The Role Of Pitx Proteins In Early Xenopus Development, Ye Jin

Dissertations, Theses, and Capstone Projects

Embryos of the African clawed frog Xenopus laevis are widely used for the study of early vertebrate development. The cement gland, which secrets mucus to help tadpoles attach to solid supports and live in relative safety, has long been used as a model to study the interplay between cell signaling pathways and transcription factors. It has been proposed that an intermediate level of Bone Morphogenetic Protein (BMP) signaling is essential for cement gland formation. In addition, several transcription factors have been linked to cement gland development. Among them, the homeodomain proteins Pitx1 and the closely related Pitx2c can generate ectopic …

The Role Of T-Box Proteins In Vertebrate Germ Layer Formation And Patterning, Sushma Teegala

Dissertations, Theses, and Capstone Projects

All of the tissues in triploblastic organisms, with the exception of the germ cells, arise from the three germ layers, ectoderm, mesoderm and the endoderm. The identification of the genes that underlie the differentiation of these layers is crucial to our understanding of development. T-box family proteins are DNA-binding transcriptional regulators that play important roles during germ layer formation in the early vertebrate embryo. Well-characterized members of this family, including the transcriptional activators Brachyury and VegT, are essential for the proper formation of mesoderm and endoderm, respectively. To date, T-box proteins have not been shown to play a role in …

Morphogenesis And Growth Driven By Selection Of Dynamical Properties, Yuri Cantor

Dissertations, Theses, and Capstone Projects

Organisms are understood to be complex adaptive systems that evolved to thrive in hostile environments. Though widely studied, the phenomena of organism development and growth, and their relationship to organism dynamics is not well understood. Indeed, the large number of components, their interconnectivity, and complex system interactions all obscure our ability to see, describe, and understand the functioning of biological organisms.

Here we take a synthetic and computational approach to the problem, abstracting the organism as a cellular automaton. Such systems are discrete digital models of real-world environments, making them more accessible and easier to study then their physical world …

Optimizing A Method For Simultaneous Recovery Of Proteins And Dna From Fingerprints, Steven Kranes

Student Theses

DNA testing on touched objects is a valuable tool in forensic investigations, but DNA is usually present in low amounts, causing poor STR typing results. For touch DNA evidence, there is a clear need for additional individualization, especially for highly probative samples. This could be achieved by testing genetically variable proteins. The goal of this project was to develop a DNA/protein co-extraction method to facilitate DNA and protein testing on the same evidence item. Existing DNA extraction methods were carefully adjusted to allow for downstream mass spectrometry analysis. Initial experiments on saliva and fingerprints placed on glass suggested that trypsin …

Body Size Regulation Via Bmp Signaling In Caenorhabditis Elegans, Uday Madaan

Dissertations, Theses, and Capstone Projects

The body size of an organism can be a crucial determinant of access to nutrition, reproductive success and overall survival in the wild. However, how body size of an individual is determined is incompletely understood. Body size is a complex trait determined by multiple pathways and genes, making it difficult to understand the role of individual genes and pathways in determining overall size. In Caenorhabditis elegans, a homolog of Bone Morphogenetic Proteins (BMP) is a major regulator of body size; functional loss of DBL-1 leads to a small body size. Due to a drastic change in body size in dbl-1 …

The Recycling Gtpase, Rab-10, Regulates Autophagy Flux In Caenorhabditis Elegans, Nicholas J. Palmisano

Dissertations, Theses, and Capstone Projects

Autophagy and endocytosis are two cellular pathways that are vital to cell growth and homeostasis. Autophagy is a dynamic and catabolic process involving the formation of a double-membrane vesicle called the autophagosome, which engulfs long-lived proteins and damaged organelles. Endocytosis involves the uptake of extracellular material into the cell through the formation of intracellular vesicles termed endosomes. Although both endocytosis and autophagy are interconnected processes, the extent to which endocytic proteins and/or compartments contribute to autophagy, and how these endocytic components do so, is still unknown. To improve our understanding of the connections that exist between autophagy and endocytosis, we …

The P53 Independent Functions Of Estrogen-Activated Mdm2 In Cell Signaling And Mammary Architecture, Nandini Kundu

Dissertations, Theses, and Capstone Projects

Estrogen receptor positive (ER+) breast cancers often have MDM2 overexpression indicating a critical role for MDM2 in breast cancer tumorigenesis. The cancer genome atlas (TCGA) found that increased MDM2 expression is one of the four pathways that correlate with all breast cancer subtypes. MDM2 is mainly known as the negative regulator of wild type p53. However, aggressive breast cancers often have MDM2 overexpression and mutant p53 (mtp53). We previously reported that MDM2 provides an estrogen-mediated proliferative advantage to MCF-7 breast cancer cells (ER+, MDM2 overexpression, wild type p53), independent of wild type p53 in both 2D and 3D culture conditions. …

Lipid Sensing By Mammalian Target Of Rapamycin, Deepak Menon

Dissertations, Theses, and Capstone Projects

Mammalian target of Rapamycin (mTOR) is a protein kinase that integrates nutrient and growth factor signals to promote cellular growth and proliferation. mTOR exists in two complexes - mTORC1 and mTORC2 that are distinguished by their binding partners and signaling inputs. mTORC1 is responsive to growth factors, amino acids and glucose and is associated with Raptor; whereas, mTORC2 is responsive primarily to growth factors and is associated with Rictor. Raptor and Rictor confer substrate specificity to mTORC1 and mTORC2 respectively. Phosphatidic acid (PA), a lipid second messenger and a central metabolite for membrane phospholipid biosynthesis, is required for the stability …

Post-Transcriptional Regulation Of The Drosophila Anterior Determinant, Bicoid, John Mclaughlin

Dissertations, Theses, and Capstone Projects

In a wide variety of biological contexts, messenger RNA (mRNA) is known to have a complex and dynamic life cycle. In particular, the localization and translational control of mRNA are essential for proper development in eukaryotes. The fly Drosophila melanogaster is an excellent model for studying these processes. During D. melanogaster oogenesis, several mRNAs are trafficked and localized within the developing egg chamber, and regulated at the translational level to enable embryo patterning. One such mRNA, bicoid, is localized at the anterior of the oocyte and translated in the early embryo, where its encoded protein directs formation of the fly's …

Environmental Changes Turn On The Sinorhizobium Melitloti Exor-Exos/Chvi (Rsi) Host Invasion Switch, Shari N. Walcott

Dissertations, Theses, and Capstone Projects

The free-living Gram-negative soil bacterium, Sinorhizobium meliloti, must switch into its host-invading form in order to infect the root hairs of the host plant, alfalfa (Medicago sativa), and establish a nitrogen-fixing symbiosis. The activation of the switch is believed to occur inside the infection chamber that is formed by curling of the root hairs. It is not fully understood what signals in the environment of the root hairs trigger and infection chamber S. meliloti to switch into a host-invading form since these signals were not extensively examined until now. This switch can be observed directly, due to …

Transcriptional And Post-Transcriptional Regulation Of Histone Variant H2a.Z During Sea Urchin Development, Mihai Hajdu

Dissertations, Theses, and Capstone Projects

Histone variant H2A.Z promotes chromatin accessibility at transcriptional regulatory elements and is developmentally regulated in metazoans. We characterize the transcriptional and post-transcriptional regulation of H2A.Z in the purple sea urchin Strongylocentrotus purpuratus. H2A.Z depletion by antisense translation-blocking morpholino oligonucleotides during early development causes developmental collapse, in agreement with its previously demonstrated general role in transcriptional multipotency. During H2A.Z peak expression in 24-h embryos, endogenous H2A.Z 3’ UTR sequences stabilize GFP mRNAs relative to those with SV40 3’ UTR sequences, although the 3’UTR of H2A.Z does not determine the spatial distribution of H2A.Z transcripts during embryonic and postembryonic development. We …