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Full-Text Articles in Life Sciences

The Impacts Of Environment And Host Evolutionary Relationships On Lemur Microbiota, Rachel B. Burten Mar 2024

The Impacts Of Environment And Host Evolutionary Relationships On Lemur Microbiota, Rachel B. Burten

Doctoral Dissertations

Recent studies have shown that the mammal microbiome is modified by environmental conditions, and that reduced microbiome functionality is associated with host health issues. Microbiome data in wild and captive primate populations can therefore be used to assess their health as they encounter a variety of environments. Comparative studies of the microbiome can also inform disease ecology, conservation, and captive management strategies tailored to different primate species. Therefore, this study examines how the hair, oral, and gut microbiota of nine wild and captive lemur species are determined by host phylogenetic relationships and host environment. I found that host species identity …


Unraveling Plant-Microbe-Microbe Interactions: Host And Microbial Colonization Determinants Across Experimental Scales, Bridget O'Banion May 2023

Unraveling Plant-Microbe-Microbe Interactions: Host And Microbial Colonization Determinants Across Experimental Scales, Bridget O'Banion

Doctoral Dissertations

Plant microbiomes are assembled and modified through a complex milieu of biotic and abiotic factors. Despite dynamic and fluctuating contributing variables, specific host and microbial mechanisms are likely important mediators of interactions. We combine information from large-scale datasets across diverse plant hosts with experimental genetic manipulation assays in model Arabidopsis seedlings to converge on a conserved role for metabolite production and transport in mediating host-microbe interactions. Applying a diverse set of analytical tools to microbial communities at various complexity levels will advance our knowledge of the scalability of observed phenotypes and, ultimately, help to decipher the mechanisms dictating plant–microbe interactions …


Bifidobacterial Metabolism Of Fucosylated Human Milk Oligosaccharides Influences Structure And Function Of The Infant Gut Microbiome, Liv R. Dedon Apr 2023

Bifidobacterial Metabolism Of Fucosylated Human Milk Oligosaccharides Influences Structure And Function Of The Infant Gut Microbiome, Liv R. Dedon

Doctoral Dissertations

Human milk contains human milk oligosaccharides (HMOs) that are indigestible and pass intact through the infant gastrointestinal tract where they are available for microbial metabolism. HMOs incorporate the same monosaccharide building blocks but vary structurally in primary sequence of monomeric components. Primary sequences are further diversified by degree of polymerization, branching, and secondary modifications such as fucosylation. Fucosylated HMOs (fHMOs) are highly abundant and can account for over 30% of total HMOs. Infant-colonizing Bifidobacterium longum subsp. infantis (B. infantis) possesses a specialized gene cluster conveying the ability to metabolize fHMOs. This study presents an in-depth analysis of B. …


Accurate Simulation Of Reads And Improved Strategies For Abundance Estimation Supporting Reduced Representation Sequencing For Metagenomics, Ryan Kuster Dec 2022

Accurate Simulation Of Reads And Improved Strategies For Abundance Estimation Supporting Reduced Representation Sequencing For Metagenomics, Ryan Kuster

Doctoral Dissertations

Next generation sequencing has impacted all areas of biology by providing affordable investigations into some of the most complex processes underpinning life. With its ubiquitous application, there is still benefit in considering the nuances of the technology and its downstream analysis. Sequencing libraries produced by fragmenting DNA with restriction enzyme digests limit the scope of sequencing to a reduced set of genomic loci, allowing for deeper sequencing of those regions at a reduced cost per sample. These sequencing libraries have been used to determine genetic markers within populations of closely related individuals due to their sensitivity and preservation within populations. …


Multi-Omic Systems Biological Analysis Of Host-Microbe Interactions, Piet Jones May 2022

Multi-Omic Systems Biological Analysis Of Host-Microbe Interactions, Piet Jones

Doctoral Dissertations

Systems biology offers the opportunity to understand the complex mechanisms of various biological phenomena. The wealth of data that is produced, at an increasing rate, provides the potential to meet this opportunity. Here we take an applied approach to integrate multiple omic level data sources in order to generate biologically relevant hypotheses. We apply a novel analysis pipeline to model both, in concert, the microbial and transcriptomic signature from COVID-19 positive patients. We show patients may suffer from an increased microbial burden, with an increased pathogen potential. Gene expression evidence further shows patients may exhibit a compromised barrier immunity, owing …


The Effects Of Urbanization On The Avian Gut Microbiome, Mae Berlow May 2021

The Effects Of Urbanization On The Avian Gut Microbiome, Mae Berlow

Doctoral Dissertations

The gut microbiome influences and is influenced by the host, and can affect the host organism by contributing to health, development and immunity. Similarly, the host can influence this community; it’s makeup can vary with host species, locality, diet, social stressors, and environmental stressors. Some of these environmental stressors have arisen due to human-induced rapid environmental change, like urbanization. The physiology and behaviors of organisms that are able to persist in urban environments are often different from their non-urban congeners. Nutrition, development, and immunity—all of which are affected by the gut microbiome—are important factors that can determine survival in urban …


Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma Dec 2020

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma

Doctoral Dissertations

The mucosal barrier in the intestine is vital to maintain selective absorption of nutrients while protecting internal tissues and maintaining symbiotic relationship with luminal microbiota. This bio-barrier consists of a cellular epithelial barrier and an acellular mucus barrier. Secreted mucus regulates barrier function via in situ biochemical and biophysical interaction with luminal content that continually evolves during digestion and absorption. Increasing evidence suggests that a mucus barrier is indispensable to maintain homeostasis in the gastrointestinal tract. However, the importance of mucus barrier is largely underrated for in vitro mucosal tissue modeling. The major gap is the lack of experimental material …


More Than The Sum Of Their Parts: Building A Framework For Understanding Host-Microbe Interactions In Medicago Sativa, Katherine Mackenzie Moccia Dec 2020

More Than The Sum Of Their Parts: Building A Framework For Understanding Host-Microbe Interactions In Medicago Sativa, Katherine Mackenzie Moccia

Doctoral Dissertations

This dissertation seeks to understand plant-microbe interactions in the agriculturally relevant plant Medicago sativa from three distinct vantage points within microbiology. Within the plant microbiome, we examine how primer usage and the application of peptide nucleic acids impacts 16S and 18S rRNA gene sequencing. In doing so, we design a novel peptide nucleic acid, PNA, and test its impact using multiple primers and sequencing protocols. Once microbial sequencing methodology is established, we generate a synthetic consortium of bacterial isolates from M. sativa leaves and modulate nitrogen levels to better understand microbial structure. Drop out communities, where we remove one member …


Extracting Detailed Metabolic Information And Connections From Mammalian Gut Microbiomes Via Metaproteomics, Jose A. Blakeley-Ruiz Dec 2020

Extracting Detailed Metabolic Information And Connections From Mammalian Gut Microbiomes Via Metaproteomics, Jose A. Blakeley-Ruiz

Doctoral Dissertations

A diverse community of bacteria populates the mammalian gastrointestinal tract. These populations exist in a balance with the host assisting with key functions, particularly metabolism of intractable fibers and immune modulation. Disruption of this balance can lead to diseases such as infection, inflammatory bowel syndrome, and obesity. Common symptoms include chronic pain, chronic inflammation, and altered metabolism. Several taxonomic classifications of bacteria have been associated with these diseases, but Recent studies have indicated that these finding are not always statistically valid. An explanation for this is that microbial communities between individuals and even across time can vary substantially even when …


Changes In Soil Microbial Communities After Long-Term Warming Exposure, William G. Rodríguez-Reillo Oct 2019

Changes In Soil Microbial Communities After Long-Term Warming Exposure, William G. Rodríguez-Reillo

Doctoral Dissertations

Microbial metabolism is a key controller of ecosystem processes (e.g., carbon cycling). However, we are only starting to identify the molecular mechanisms and feedback in response to long-term warming. My dissertation integrates multi-omics techniques to capture changes in soil microbial communities after long-term warming exposure. The research projects leverage three warming sites (i.e., SWaN, Barre Woods, and Prospect Hill) located in Western Massachusetts at Harvard Forest. These sites provided a unique experimental setup to better understand microbes in response to long-term temperature change. For the three research projects, we delved into the (i) microbial biodiversity across all three warming sites, …