Life Sciences Commons^™

Microbiome Assembly And Function In The Solitary Mason Bee, Osmia Lignaria (Megachilidae), Bailey Crowley

All Graduate Theses and Dissertations, Fall 2023 to Present

Animal-microbe interactions can influence host biology, ecology, and evolution. The assembly and function of microbes found within animal hosts oftentimes depends on which species are involved. Advances in sequencing technologies have permitted the exploration of host-microbe interactions in a variety of animals, including bees. Early research aimed at understanding the microbiomes of social bees, such as honey bees and bumble bees, found that microbes prevent the spoilage of stored pollen, breakdown indigestible nutrients into smaller molecules available for uptake by the host, and also protect the host from pathogens. When environmental stressors, such as increased temperatures, disrupt the microbiome, the …

Host-Microbe Interactions In Non-Native Estuarine Anemones: Biogeography And Temperature, Parker K. Lund

Cal Poly Humboldt theses and projects

Non-native species are increasing in prevalence around the world, resulting in negative economic and ecological impacts. However, the broad distributions of non-native species also offer a system for investigating the response of host-associated microbial communities to environmental factors across a range of ecological scales. At the broadest scale, I investigated the geography of microbial communities in the non-native estuarine anemone Diadumene lineata on the west coast of the United States of America. Across latitudes, microbial community composition was very similar and displayed a high percentage of Klebsiella spp. at all sites. However, the communities in California tended to exhibit higher …

An Analysis On How Housing Status Influences The Gut-Brain-Axis For Populations In And Around The Skid Row Area Of Los Angeles, California, Mauricio Guzman

Pitzer Senior Theses

Over recent years, the “microbiota-gut-brain axis” (MGBA) has garnered significant attention in the scientific community. Specifically, perturbations of the MGBA via stress and dietary intake have been linked to a wide-range of diseases including gastrointestinal diseases, metabolic diseases, mood disorders, and cognitive diseases. However, most studies have been solely conducted on mice models and have yet to consider the more complex, intricate systems that impact the human body. In addition, researchers have yet to consider the populations who may be most susceptible to chronic stress and negative dietary outcomes. Drawing from the fields of medical sociology, non-invasive human biology, and …

A Bioinformatics Analysis Of Microbial Diversity And Its Correlation With Human Lifestyle, Diet, And Health Variables, Alivia Ankrum, Kate Cooper

Theses/Capstones/Creative Projects

The abundant impact of microbiota on human physiology suggests a need for exploration into their impact on human health and disease. The American Gut Project (AGP) was established to aggregate microbiome sequencing data as well as health, diet, and lifestyle metadata. This study proposes to identify taxonomic species and build a phylogenetic tree representation from the AGP participant sample collection as well as find their respective alpha and beta diversity of all metadata variables based on patient questionnaire data. Additionally, this study will involve a chimeric sequence extraction from the 16S rRNA sequences of the AGP. The expected results are …

Ohio Anuran Gut Microbiomes, Serena Hoffman

Undergraduate Honors Thesis Projects

Recent studies focusing on the skin and gut microbiome of vertebrates have found how important microbiomes are to maintaining host health. Understanding the role the gut microbiome plays to host health is of great importance for conservation. Less is known about the gut microbiome than the skin microbiome for amphibians. Literature is especially lacking for local Ohio anuran species. The purpose of this study was to establish the baseline composition of the gut microbiome for local Ohio anurans and to determine whether host species or habitat is the best predictor of gut microbiome composition. Tadpoles were collected from seven different …

Investigating The Bactericidal Activity Of Lactobacillus Crispatus Cell-Free-Supernatant, Omar Majed Abdul-Rahim

Dissertations

Antimicrobial-resistant (AMR) microorganisms are an increasingly seriousproblem worldwide, accounting for thousands of fatalities annually. The current literature on combating AMR pathogens often centers on commensal microbes such as Lactobacillus species, which are most frequently found in asymptomatic ‘healthy’ patients and are believed to elicit protective effects. In this dissertation, I sought to investigate the protective effect of Lactobacillus crispatus, utilizing our vast collection of clinical isolates. Previous work from our lab had found that cell-free-supernatant (CFS) of L. crispatus is robustly bactericidal, and that this killing activity does not depend on hydrogen peroxide or lactic acid. We identified phenyl-lactic acid …

Microbial Community Dynamics During Key Life History Transitions In The Deep-Sea Chemosymbiotic Mussel, Gigantidas Childressi, Tessa F. Beaver

WWU Graduate School Collection

Marine invertebrates form specific associations with bacterial communities that are different from their environment, change throughout their development, and shape evolutionary and ecological processes. The bathymodiolin (Mytilidae) mussel Gigantidas childressi lives at deep-sea methane seeps and relies on methanotrophic endosymbionts for its nutrition. Its larval life, however, is spent feeding in the water column. Upon metamorphosis at a suitable seep habitat, methanotrophic bacteria rapidly colonize gill cells and the juvenile mussel switches to symbiont-derived energy. To determine if the microbiome of the G. childressi changes during these transitions, the V3/V4 region of the 16S rRNA gene was sequenced to census …

From Microbes To Management: Spatial And Temporal Variations In Available Vegetation Affect The Gut Microbiota In A Population Of Free-Ranging Generalist Herbivores, Olivia K. Rodríguez

Boise State University Theses and Dissertations

The effects of extrinsic environmental factors that shape ecological systems are not only seen at the macroscopic level, but additionally influence and govern the host-associated microbial communities of their mammalian hosts. These microbial communities are susceptible to the fluctuation of abiotic and biotic factors which affect their host organisms. The surge in the research of microbiota–communities of archaea, bacteria, fungi, and viruses residing in various environmental systems–has shown that these communities can profoundly influence animal health. As such, monitoring microbiota has allowed for a new approach to study animal health and physiology. This is of particular benefit in the conservation …

The Brown Bear Gut Microbiome: A Novel Tool For Conservation & Management, Sarah M. Trujillo

All NMU Master's Theses

Gut microbiomes (GMBs), complex communities of microorganisms inhabiting the gastrointestinal tracts of their hosts, perform countless micro-ecosystem services such as facilitating energy uptake and modulating immune responses. While scientists increasingly recognize the role GMBs play in host health, the role of GMBs in wildlife ecology and conservation has yet to be realized fully. Here, I use brown bears (Ursus arctos) as an ecological model to investigate (1) how both extrinsic and intrinsic factors influence GMB community membership and structure; and (2) the correlation between GMB membership and brown bear health metrics. To achieve these aims, I subsampled archived …

Factors Influencing Primate Hair Microbiome Diversity, Catherine Kitrinos

Masters Theses

Primate hair is both a substrate upon which essential social interactions occur and an important host-pathogen interface. As commensal microbes provide important immune functions for their hosts, understanding the microbial diversity in primate hair could provide insight into primate immunity and disease transmission. While studies of human hair and skin microbiomes show differences in microbial communities across body regions, little is known about the nonhuman primate hair microbiome. In this study, we collected hair samples (n=159) from 8 body regions across 12 nonhuman primate species housed at 3 US institutions to examine 1) the diversity and composition of the primate …

Comparative Microbiome Analysis Of The Funfus Gardening Ant Species Trachymyrmex Arizonensis, Chase D. Rowan

Biology Theses

Fungus-growing ants (Attini: Formicidae) and their fungal cultivars participate in ant-fungus mutualism that share a 50-million-year-old coevolutionary history. Fungal cultures are grown in gardens alongside ants and a diverse collection of microbes that interact with both species in mutualistic, commensal, and antagonistic relationships. These microbes aid in digestion and detoxification of food, provide essential nutrients, help in nest hygiene, and play a dominant role in defense against pathogens and disease. Microbial communities of many model species have been shown to change in a laboratory setting as compared to their natural environment. High-throughput 16s sequencing of the V4 variable region was …

Ecophysiology Of Toxic Bloom-Forming Cyanobacteria And Their Symbionts, Dominique J. Lockwood

Masters Theses, 2020-current

Currently, there is a pernicious microbe in the genus Microcystis that is putting the world’s freshwater resources at risk. A member of the phylum Cyanobacteria, otherwise referred to as blue-green algae, Microcystis forms massive algal blooms in lakes and has the potential to produce a toxin, which does not only harm humans, but also pets, livestock, and aquatic life. As recently as 2016, in the city of Toledo, Ohio, nearly 1 million residents went without clean drinking water for an entire weekend due to one of these Microcystis blooms. However, Microcystis does not only bloom in Ohio. In fact, …

Neuroinflammation, Peripheral Inflammation And Gut Microbiome Profiles In Male Mice From Two Proposed Mouse Models Of Social Behavior Deficits, Sarah Parkinson

Electronic Theses and Dissertations

Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by social deficits and repetitive actions. A communication pathway exists between the brain and gut called the gut-brain axis. It is thought that gut bacteria can secrete signaling molecules, triggering inflammation across the body. These studies attempt to determine if markers are expressed in two mouse models of ASD behaviors, BTBR and a valproic acid model. Immunohistochemistry of ionized calcium binding adaptor molecule 1 from male mouse brain tissue showed no microglial activation in any group. Cytokine analysis did exhibit an increase in interleukin 1 (IL-1) in male adult mice only. …

Dynamics Of The Soil Microbiome In Ginseng Gardens, Megan E. Lambert

Electronic Thesis and Dissertation Repository

Ginseng Replant Disease (GRD) is a syndrome in which ginseng cannot be cultivated in soil previously used to grow ginseng. Since GRD can persist for decades, it severely impacts the Ontario ginseng industry. To better understand the origin of GRD, the impact of ginseng cultivation on the soil microbiome was investigated in bulk soil of three newly planted ginseng gardens in Ontario, from seeding through two years of cultivation. While specific trends in species richness, diversity and composition were unclear, PERMANOVA analyses confirmed that they changed over time. Known GRD-related pathogens, including Ilyonectria mors-panacis and Fusarium oxysporum, were detected in …

Roles Of Non-Frankia Bacteria In Root Nodule Formation And Function In Alnus Sp., Kelsey Christine Mercurio

Honors Theses and Capstones

Plant roots are home to a wide variety of beneficial microbes; understanding and optimizing plant-microbe interactions may be critical to enhance global food security in a sustainable, equitable way. With the help of their nitrogen-fixing bacterial partner, Frankia, actinorhizal plants form symbiotic root nodules and play important roles in agroforestry and land reclamation. However, Frankia does not live alone in nodules, and the other microbial residents may contribute to nodule formation and function. We collected root nodules from alder trees (Alnus sp.) in 2018 and 2019, then isolated DNA and individual bacterial strains to characterize the nodule microbial …

The Effects Of Saline Soil On Microbiome And The Isolation Of Root-Associated Microbes To Relieve Salinity Stress, Duncan Jakubowski

Electronic Theses and Dissertations

Increasing levels of salinity in once-viable lands for crop production is a serious and growing problem in the Northern Great Plains. The objectives of this study were to determine the effects of saline soil on the microbial composition of plant roots and bulk soil, to measure metabolic changes in plant roots from saline soil, to determine the viability of root-associated microbes as inoculants to increase stress tolerance in plants, as well as determine the impact of saline soil on nitrogen cycling genes linked to greenhouse gas production. This study hypothesizes that high soil salinity levels have a significant impact on …

Drivers Of Rickettsial Pathogen Transmission And Spillover In Local Tick Populations In Southeastern Virginia, Alexandra Cumbie

Biomedical Sciences Theses & Dissertations

Cases of spotted fever group rickettsiosis are becoming more prevalent in the United States. In Virginia, there are three human-biting ticks which are largely responsible for the spread of rickettsial pathogens and the increase in disease cases. These species include Dermacentor variabilis, Amblyomma americanum, and Amblyomma maculatum; all of which are vectors of rickettsial agents to vertebrate hosts. These species are sympatric as adults and have the potential to share large and small mammal hosts. Their interactions on and off host and their associated rickettsiae were the focus of this dissertation work. Amblyomma americanum is the vector …

Characterizing The Diversity Of The Eukaryotic Microbiome In Marine Crustacean Zooplankton., Rose-Lynne Savage

Electronic Thesis and Dissertation Repository

Understanding zooplankton productivity is critical for modeling marine food web function, of which one poorly known factor is the influence of zooplankton symbionts. Zooplankton protist symbiont diversity is underestimated due to the limited surveys and techniques previously used. Using 18S V4 metabarcoding, I characterized the eukaryotic microbiomes associated with crustacean zooplankton from the northern Strait of Georgia, BC. Apostome ciliates were most abundant in all hosts except for cyclopoid copepods, which were dominated by Syndiniales. Most symbiont lineages were more abundant in one or two hosts, suggesting some degree of host preference. Microbiome data also provided information on diet, confirming …

Genetic Population Structure And Microbiome Of German Cockroaches In Urban Environments, Xueyang Fan

Dissertations

Pests of human habitats may harbor and disperse pathogens that cause human disease. One such pest is the German cockroach (Blattella germanica), which is known to harbor numerous pathogens, including Klebsiella and Pseudomonas. The aim of this study is to reveal the importance of the German cockroach as a potential vector of human medically important diseases. To do so, this study investigates German cockroach population structure and their associated bacterial microbiome in urban residential environments. Ninety German cockroaches are collected from three residential apartment buildings in three New Jersey cities. Samples are caught by glue traps and stored at -20°C. …

The Roles Of Host Species, Geographic Scale And Environmental Stressors In Shaping The Composition Of Coral Microbiomes, Alicia Marie Riegel Parker

LSU Doctoral Dissertations

Reef-building corals are long-lived and may take many centuries to adapt, making them especially susceptible to climate change. However, corals host microbial symbionts that can change quickly, potentially speeding acclimation. My dissertation aimed to determine the degree of coevolution and flexibility between corals and their microbiomes among hosts, across space, and in response to stress.

Microbial communities are usually surveyed by sequencing the 16S rRNA gene, however the PCR primers used also amplify coral DNA, thereby limiting prokaryotic read coverage. To mitigate this contamination, I designed a peptide nucleic acid clamp that increased the recovery of bacterial reads by 2-11x …

The Effects Of An Applied Phyllosphere-Microbiome On Gas Exchange And Growth Of Soybean Infected With Pseudomonas Syringae: Harnessing The Power Of The Microbiome, Charles Agbavor

MSU Graduate Theses

The microbiome is an important determinant of plant health, growth and resistance to stress. This study was conducted to determine the efficacy of the phyllosphere-microbiome on managing Pseudomonas syringae pv. Glycinea (Psg), gas exchange and growth of Glycine max L. Merrill. A greenhouse study was conducted in the summer of 2019. A field isolated and cultured soybean phyllosphere-microbiome was applied to purposely infected and uninfected soybean. Gas exchange, Psg density, chlorophyll concentrations, and percent nitrogen and carbon in the leaves were measured during the V3-V6 stages of soybean. Not surprisingly, there was a two-fold reduction in copies of Pseudomonas …

Accessing The Functional Capabilities Of The Tick Microbiome Through Metagenomics, Darin Lee Shrewsberry Jr

Graduate Theses, Dissertations, and Problem Reports

The black-legged tick Ixodes scapularis is a common ectoparasite of animals and an obligate blood feeder, attaching to a host animal and taking a blood meal once per life stage (i.e. 3 times during its life). Unfortunately for the tick, blood represents a nutrient poor diet largely consisting of lipids and proteins but notably lacking in essential nutrients such a B vitamins (e.g., biotin, riboflavin, niacin) Other exclusive blood feeders such as the tsetse fly harbor symbiotic bacteria that provision B-complex vitamins to their host. I. scapularis harbors Rickettsia buchneri an endoparasitic bacterium that intriguingly possesses two copies of a …

Secretory Iga Enhances Gut B Cells Priming And Systemic Igg Responses Towards Commensals, You Zhou

Arts & Sciences Electronic Theses and Dissertations

IgA is the primary antibody response at mucosal surfaces and is reported to inhibit adaptive immune responses against gut bacteria. Here, we utilize an in vitro system to expand and screen IgA memory B cells for their ability to recognize gut bacteria in the context of secretory IgA (sIgA) deficiency in polymeric Ig receptor (Pigr–/–) mice. Contrary to the prevailing hypothesis that IgA provides an immune exclusionary function, we found that mice lacking sIgA showed decreased anti-bacterial IgA specificities as assessed using flow cytometry. IgA B cell responses against certain taxa such as those of order Bacteriodales showed greater dependence …

Mechanisms Of Nestmate Recognition Cue Production In The European Honey Bee, Apis Mellifera., Cassondra Leigh Vernier

Arts & Sciences Electronic Theses and Dissertations

Social insects are some of the world’s most ecologically successful animal groups, and their complex societies are considered one of the pinnacles of animal evolution. Since these organisms live in colonies composed of many individuals and stored resources, they are a target for intruders, such as parasites, predators and conspecific robbers. Therefore, many social insect species have evolved mechanisms for nest defense, including nestmate recognition, where guarding individuals at the entrance of the colony use cues on incoming individuals to determine whether they are nestmates or intruders. Although nestmate recognition is incredibly important for maintaining colony integrity and fitness, the …

The Endosymbiotic Gut Fungus Zancudomyces Culisetae Influences Transstadial Transmission Of Host-Associated Microbiota In The Yellow Fever Mosquito (Aedes Aegypti), Jonas Frankel-Bricker

Boise State University Theses and Dissertations

Mosquitoes are vectors for a variety of human pathogens and have a significant impact on human health worldwide. There is growing evidence that host-associated microbiota influence mosquito vector competence for certain viruses. Transstadial transmission of bacteria from larvae through pupae to adults could affect these interactions, though further studies are needed to fully unravel the mechanisms involved. Current microbiome research primarily focuses on bacterial communities, whereas the potential role endosymbiotic gut fungi have in transstadial transmission dynamics remains largely unknown. Trichomycetes is an ecological group of endosymbiotic microfungi that colonize the digestive tracts of arthropod hosts, including the Yellow Fever …

Alcohol Induced Bacterial Changes In The Setting Of Colitis, Paulius Kuprys

Dissertations

Inflammatory bowel diseases (IBD) affect a large number of individuals around the world. This group of diseases is largely composed of two types: Crohn's disease (CD) and ulcerative colitis (UC). Upon development of IBD, patients experience cyclical episodes of inflammation, known as flares. Flare induction appears to arise from multiple factors, which can also vary on a person-to-person basis. Alcohol has been shown to trigger IBD flares and onset, though the underlying mechanism has not been established.Defining factors of the IBD intestinal environment include an altered microbiome, bacterial infiltration of the intestinal epithelium, and increased leakage of proinflammatory bacterial byproducts. …

Coaggregation Patterns And Surface Characteristics Of Lactobacillus Rhamnosus Gg Under Varying Nutrient Conditions, Amanda Rielinger

Senior Honors Theses and Projects

Lactobacillus rhamnosus GG (LGG) is one of the best studied probiotic organisms. The ability of probiotics to adhere to other microorganisms and the intestinal epithelium is thought to play a major role in their protective functions. Coaggregation is an important mechanism for biofilm formation by microorganisms. The goals of this study were to examine the ways in which nutrient variation affects intercellular interactions between LGG and other gut microbes and the hydrophobic character of LGG. We hypothesized that nutritional variation may affect the ability of LGG to coaggregate and form biofilms and thus affect its probiotic characteristics and ability to …

Environnmental Influences On Caribbean Octocoral-Symbiodiniaceae Symbioses, Mark Mccauley

Electronic Theses and Dissertations

A Caribbean octocoral colony is an assemblage of the octocoral host, dinoflagellate algae (family Symbiodiniaceae), bacteria and other microbes, together functioning as meta-organism (holobiont). Even though octocorals dominate many Caribbean reefs, compared to scleractinian corals, little is known about their biology under ambient or potentially stressful conditions. Of the nine species of octocorals (gorgonian corals, Order: Alcyonacea) studied, each had significantly different polyp behaviors, biochemical compositions, Symbiodiniaceae parameters, isotopic signatures, in addition to hosting distinct microbial assemblages. We identified multiple Symbiodiniaceae species (Breviolum minutum, Breviolum B41, Breviolum B1a and Breviolum B1i), inhabiting the gorgonians. These symbioses were temporally and …

Midguts, Microbes, And Mosquitoes: An Analysis Of The Microbiomes Of Aedes Aegypti And Aedes Albopictus, Flor Alicia Martinez

Theses and Dissertations

Experiment 1: Mosquito microbiomes are influenced by the environment and diets of mosquitoes. There is great variability within and among mosquito populations with few microbe inhabitants being well established among mosquitoes of similar species and environments. By understanding the potential variation in midgut microbiomes in lab and wild populations, we may assess the effect that microbiomes have on vector competency.

Experiment 2: Mosquito midgut microbes are essential for development and may influence the vector competency. Native and non-native strains of the midgut inhabitant, Cedecea, were introduced to laboratory colonies of Aedes aegypti and Aedes albopictus mosquitoes to help elucidate …

Microbial Ecology Of South Florida Surface Waters: Examining The Potential For Anthropogenic Influences, Chase P. Donnelly

HCNSO Student Theses and Dissertations

South Florida contains one of the largest subtropical wetlands in the world, and yet not much is known about the microbes that live in these surface waters. These microbes play an important role in chemical cycling and maintaining good water quality for both human and ecosystem health. The hydrology of Florida’s surface waters is tightly regulated with the use of canal and levee systems run by the US Army Corps of Engineers and The South Florida Water Management District. These canals run through the Everglades, agriculture, and urban environments to control water levels in Lake Okeechobee, the Water Conservation Areas, …