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The Nature And Extent Of Algal Symbiosis In Three North American Ranids, Zachary T. Vegso

Cal Poly Humboldt theses and projects

The symbiotic relationship between the chlamydomonad green alga Oophila amblystomatis and embryos of certain amphibian species is often presumed to be mutualistic. However, the existence of a mutualism has only been experimentally tested and established in two closely related ambystomatid salamanders. These experiments showed a positive correlation between intracapsular algal density and embryonic growth, survival, hatching synchrony, and hatchling body size. Oophila has been documented within egg capsules of a growing number of amphibian species, including several frogs in the family Ranidae. However, the nature and extent of this relationship remains unclear. Ranid eggs are better oxygenated than ambystomatid eggs, …

The Influence Of Intracellular Photosymbiosis On The Evolution And Function Of Cnidarian Immunity, Madison A. Emery

Biology Dissertations

Intracellular photosymbiosis with Symbiodiniaceae is facilitated by cnidarian immunity as it is required for symbiont recognition and is subsequently suppressed to maintain stable intracellular symbiosis. To date, it is unclear how the cnidarian-Symbiodiniaceae symbiosis influences immune gene repertoires, immune gene expression, and disease pathology across its independent evolutions. To address these knowledge gaps, my dissertation approaches studying the cnidarian-Symbiodiniaceae symbiosis through a comparative lens to determine how it shapes immune gene evolution and immune responses in divergent symbiotic cnidarian species. In chapter two I survey eight non-symbiotic and seven symbiotic cnidarians proteomes for four families of pattern recognition receptors (PRRs) …

Investigating The Costs And Benefits Of A Nutritional Fungal Endosymbiont, Nolan L. Perryman

Biology ETDs

Research on insect symbiosis is dominated by insect–bacteria models, however, the role of fungal symbionts in insects is poorly understood. Fungi are de novo synthesizers of many essential nutrients, therefore, insect–fungal pairings can permit specialization on nutritionally deprived diets. Here, I address the costs and benefits of symbiosis using a system of beetle–fungal symbiosis. Specifically, I ask 1) when reared on a low-quality diet, does the beetle increase the number of viable symbionts to compensate for a heightened nutritional demand, and 2) Is the conferred fitness benefit of the symbiont only present in low-quality diets? When reared on low-quality diets, …

Evaluating The Effect Of Symbiodiniacea On Survival, Growth, And Acquisition Of Newly Settled Corals Of Three Caribbean Species, Michael B. Hood

All HCAS Student Capstones, Theses, and Dissertations

Symbiosis between corals and Symbiodiniaceae is critical to coral reef health. However, this mutually beneficial relationship is threatened by a variety of stressors. This study aims to assess if seeding newly settled corals with different species of Symbiodiniaceae promotes differences in survival, growth, and symbiont acquisition in corals. Three reef-building species (Colpophyllia natans, Orbicella faveolata, and Pseudodiploria strigosa) reared in sterile saltwater baths were seeded with one of four Symbiodiniaceae species (Breviolum minutum, Durusdinium trenchii, Fugacium kawagutii, and Symbiodinium microadriaticum). Coral survival, growth, and symbiont acquisition were assessed biweekly during the first two months and monthly …

Compatibility Between Native Mississippi Ectomycorrhizal Fungi And Native And Exotic Pine Hosts: Testing For Specificity And The Potential For Rapid Evolution, Hailey A. Long

Honors Theses

Pines are highly invasive trees that are commonly used in pine plantations throughout the Southern Hemisphere. However, the survival and subsequent invasion of pines in exotic environments are dependent on the obligate symbiosis between ectomycorrhizal (ECM) fungi and pines. ECM fungi vary in host specificity and compatibility from pine-specialist species in the genus Suillus to broad generalists, such as species within the genera Pisolithus and Scleroderma. In Experiment 1, we sought to understand how the geographic origin of ECM fungi native to the southeastern United States and two pine species (native southeastern United States Pinus taeda and exotic Pinus …

Does Tssh Deletion In Paraburkholderia Bonniea Affect Its Symbiosis With Dictyostellum Discoideum?, Anna Chen

Honors Theses

Paraburkholderia are amoeba resistant, gram negative bacteria that form facultative symbiotic relationships with D. discoideum, a soil dwelling amoeba host. Three species of Paraburkholderia, P. agricolaris, P. hayleyella, and P. bonniea are able to persistently infect nonnative, or symbiont free, D. discoideum. These three species share a type III secretion system (T3SS) and type VI secretion system (T6SS) that is absent in other close relatives We hypothesized that the ability to persistently infect D. discoideum may be partially attributed to the T3SS and T6SS shared across the three species of Paraburkholderia.

The goal was to test the phenotypic effect of …

The Effects Of Ericoid Inoculum Source And Nutrient Addition On Growth And Reproduction In Highbush Blueberry, Ilana Williams

Graduate College Dissertations and Theses

Ericoid mycorrhizal fungi (EMF) form symbiotic relationships with ericaceous plants such as Vaccinium corymbosum, or highbush blueberry and assist in nutrient acquisition. EMF help plants thrive in stressful environments by increasing the area in which roots can uptake water and nutrients. In plant-mycorrhizal symbioses, nutrient uptake may depend on the identity of the fungal partner. Therefore, differently sourced mycorrhizal fungi could show differences in nutrient uptake ability. Here, I hypothesized that inoculation of V. corymbosum with EMF would enhance plant growth and investment in reproduction, and that effect would be more pronounced for plants in low nutrient conditions. I also …

Investigating Plant Physiological Responses To Global Phylogenetic Diversity Of Glomeromycotina, David Z. Mowbray

Honors Undergraduate Theses

Arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of terrestrial plant species with associations predominantly characterized as mutualistic. In addition to well-documented enhancement of host growth response, more recent analyses have demonstrated the conferral of host benefits under numerous biotic and abiotic stressors. However, much of the established evidence originates from studies involving limited AM fungal diversity. Accordingly, this study sought to evaluate the potential effects of inoculation on plant host physiological traits within a growth chamber environment, investigate potential correlations between host trait responses, & assess the degree of phylogenetic signal observed in trait responses due to the presence of …

Identification Of The Type Eleven Secretion System (T11ss) And Characterization Of T11ss-Dependent Effector Proteins, Alex S. Grossman

Doctoral Dissertations

Host-associated microbes live in dangerous environments as a result of host immune killing, nutrient provisioning, and physiological conditions. Bacteria have evolved a host of surface and secreted proteins to help interact with this host environment and overcome nutrient limitation. The studies included within this dissertation describe the identification of a novel bacterial secretion system which has evolved to transport these symbiosis mediating proteins. This system, termed the type eleven secretion system (T11SS), is present throughout the Gram negative phylum Proteobacteria, including many human pathogens such as Neisseria meningitidis, Acinetobacter baumanii, Haemophilus haemolyticus, and Proteus vulgaris. Furthermore, …

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 …

Microbes On The Mountain: Plant-Microbe Associations And Interactions On Mount St. Helens, Emily Rose Wolfe

Dissertations and Theses

Plant-microbe associations and interactions provide critical context to studies in both community and ecosystem ecology, especially in systems that are relatively new and still undergoing early successional processes. Microbes can colonize the surfaces and interiors of all plant tissues, and these assemblages vary in composition both spatially and temporally, even within the same plant. Endophytes are bacteria or fungi that spend most of their lifecycles living within plant tissues asymptomatically--typically, "endophyte" refers specifically to aboveground tissues such as leaves and stems, and therefore may have direct influences on defenses against herbivory, pathogen or pest tolerance, and even afterlife effects on …

Next Generation Sequencing Identifies Population Structure And Signatures Of Local Adaptation In Red Alder (Alnus Rubra Bong.), Jacob Brent Loveless

Dissertations and Theses

Red alder (Alnus rubra Bong.) is the dominant hardwood tree species in the Pacific Northwest. Red alders are only found in western North America, generally within 200 km of the coast and below 1000 m in elevation--although there are several disjunct populations in the northern Rocky Mountains in Idaho. Commonly a riparian species, the shade intolerant red alder generates most of the leaf litter in the streams and rivers it occupies which has been shown to greatly influence the decomposer communities. This, in turn, has a cascading effect throughout the entire riparian ecosystem greatly influencing multiple levels of the …

An Experiment To Test For Rapid Evolution In An Introduced Ectomycorrhizal Symbiosis, Valerie Rewa

Honors Theses

The rapid evolution of introduced ectomycorrhizal-plant partnerships is an under- explored topic that may have immense impacts on ecosystems around the world. This experiment sought to identify and quantify this evolution and its impacts on both fungal colonization as well as plant growth. I used a laboratory experiment to analyze these factors in native and exotic genotypes of Suillus cothurnatus and Pinus species. Much of the data was not able to be collected, but that which was did not support the presence of rapid evolution in the mutualistic partnership. Pine species was seen to have a significant effect on plant …

Microbiome Community And Parasitic Infections In Wild Bees, Mark G. Young

Honors Theses

The microbiome is increasingly recognized for its complex relationship with host fitness. Akin to primates and other social animals, bumblebees harbor a specific microbiome derived from social contact. The bumblebee microbiome is characteristically species poor, with just a few “core” phylotypes accounting for the majority of total abundance. Genomic analyses reveal phylogenetic congruence and adaptation of the core endosymbionts to the bumblebee gut, indicating a shared evolutionary history. Prior investigations reveal that the relative abundance of core microbes is negatively associated with infection by a trypanosome, Crithidia bombi, and that the microbiome has a mechanistic role in immunity. As …

A Perspective On Fungal-Algal Symbioses Through Comparative Dual-Transcriptomics Of "Franken-Lichen" Tissues And "Microbial Speed-Dating" Assays, Michael Clear

Electronic Theses and Dissertations

Mutualistic symbioses are ubiquitous and among one of the most crucial biological interactions. Some of the most iconic examples are fungal-photoautotroph mutualisms such as lichens, mycorrhizal-plant, and endophytic fungal-plant symbioses. Yet little is understood about the earliest origins of such microbial mutualisms, and more precisely, how they relate to the origin of land plants. The study of the evolution of fungal-photoautotroph symbioses is often limited to comparative genomic techniques due to the few genetic tools available for studying extant interactions. Recent work suggests that extant fungal-plant interactions have their origins in fungal-algal associations.In Chapter 1, I review the evolution of …

Initial And Advanced Stages Of Microbiota Establishment Within The Tsetse Fly, Miguel Eduardo Medina Munoz

Graduate Theses, Dissertations, and Problem Reports

Symbiosis is a long-term physical association between two or more species, although little is known regarding its evolutionary origins, particularly at the genetic level. Tsetse flies are the vector of African trypanosomes, causative agents of Human and Animal African Trypanosomiases. Tsetse provide an ideal model for studying initial and advanced stages of symbiosis. Tsetse have a simple digestive tract microbiota primarily consisting of two bacteria; the ancient mutualist Wigglesworthia glossinidia and the recently acquired Sodalis glossinidius. This work presents a chronological study in evolutionary terms of the history of a microbial-insect association. First, I present concepts on symbiosis and …

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 …

Do Fungal Symbionts Of Salt Marsh Plants Affect Interspecies Competition?, Vanessa Robertson-Rojas

Dissertations and Theses

The effects of arbuscular mycorrhizal fungi (AMF) as salt marsh plant symbionts may have significant effects on landscape scale distribution patterns and plant-related ecosystem functions that are important to estuarine habitats. This work investigates the effects AMF have on Phalaris arundinacea, Deschampsia cespitosa, and Juncus balticus when grown in a common garden experiment. Plants were grown with and without AMF inoculation in both polyculture and monoculture communities and examined for a variety of response variables that represent different competition strategies. Factorial ANOVA analysis revealed a significant three-way interaction among fungal treatment type, community type, and species for …

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 Role Of Bacterial Symbionts And Bioluminescence In The Pyrosome, Pyrosoma Atlanticum, Alexis Berger

HCNSO Student Theses and Dissertations

The pelagic tunicate, Pyrosoma atlanticum, is known for its brilliant bioluminescence, but the mechanism causing this bioluminescence has not been fully characterized. This study identifies the bacterial bioluminescent symbionts of P. atlanticum collected in the northern Gulf of Mexico using various methods such as electron microscopy, light microscopy, and molecular genetics. The bacteria are localized within a specific pyrosome light organ. Bioluminescent symbiotic bacteria of Vibrionaceae composed >50% of taxa in tunicate samples (n=13), which was shown by utilizing current molecular genetics methodologies. While searching for bacterial lux genes in 2 tunicate samples, we also serendipitously generated a draft …

Symbiosis And Bioinvasive Dynamics Of Durusdinium Trenchii And Its Acroporid Coral Hosts, David Craig Lawson

HCNSO Student Capstones

Biological invasions are a growing threat to coral reef ecosystems, as increasing anthropogenic transport and changing environmental patterns allow invasive species to establish and spread. Durusdinium trenchii is a dinoflagellate that has invaded the Greater Caribbean reef system and established symbioses with coral hosts. Establishment and persistence of invasive endosymbionts like D. trenchii could indicate a shift in the clade composition of coral holobionts worldwide. Statistical analyses were performed on the GeoSymbio database (Franklin et al. 2012) to determine whether differences in clade composition have occurred over time. Factors that influence biological invasions in marine ecosystems were assessed and analogous …

Antifungal Defense Molecules From Bacterial Symbionts Of North American Trachymyrmex Ants, Georgia Scherer

CMC Senior Theses

Defensive symbioses, in which microbes provide molecular defenses for an animal host, hold great potential as untapped sources of therapeutically useful antibiotics. Fungus-growing ants use antifungal defenses from bacterial symbionts to suppress pathogenic fungi in their nests. Preliminary chemical investigations of symbiotic bacteria from this large family of ants have uncovered novel antifungal molecules with therapeutic potential, such as dentigerumycin and selvamicin.

In this study, the bacterial symbionts of North American Trachymyrmex fungus-growing ants are investigated for antifungal molecules. Plate-based bioassays using ecologically-relevant fungal pathogens confirmed that these bacteria have antifungal activity. In order to purify and identify the antifungal …

The Host Gatekeeper: Using The Flagellar Pathway To Understand Symbiont Host Adaptation, Adam R. Pollio

Graduate Theses, Dissertations, and Problem Reports

The acquisition of microbial partners is a strategy used by a diverse group of arthropods to overcome ecological barriers that might normally make certain niches uninhabitable. The unique phylogenetic opportunities attainable from the natural experiment of the Sodalis-allied clade allow for better understanding of how molecular structures evolve through time. Here, we focus on the evolution of the flagellar synthesis pathway, due to its complexity and ability to diverge in response to ecological pressures. We used this molecular pathway and natural experiment to show that normal evolutionary outcomes associated with symbiosis (i.e., genome reduction) do not explain the predicted conservation …

The Adaptations Of The Sulfur-Oxidizing, Gammaproteobacterium "Candidatus Endoriftia Persephone", Endosymbiont Of The Giant Tubeworm Riftia Pachyptila, To Hydrothermal Vent Habitat Heterogeneity, Juliana M. Leonard

USF Tampa Graduate Theses and Dissertations

The siboglinid tubeworm Riftia pachyptila is a dominant member of the deep-sea megafauna where seawater and hydrothermal vent (HTV) effluent interface and mix. It is one of the fastest growing invertebrates on land or in the sea. It does not have a digestive tract (e.g. mouth, gut, or anus), and is completely dependent on its sulfur-oxidizing endosymbiont, the Gammaproteobacterium “Candidatus Endoriftia persephone” for its nutritional requirements. This association was the first and is the most well studied among chemolithoautotrophic symbioses. “Ca. E. persephone” is a chemolithoautotrophic bacterium that oxidizes sulfide as an electron donor for energy, reduces oxygen as a …

The Lotus Japonicus Short Internodes/Stylish Gene Family And Its Role During Root Nodule Development, Arina Shrestha

Electronic Thesis and Dissertation Repository

The ability to host nitrogen-fixing bacteria, which convert atmospheric di-nitrogen to ammonia, inside root cells is a special adaptation of most leguminous and only some non-leguminous plants. It engenders the development of new, root-derived organs, called nodules. Significant research effort has been dedicated to understanding how these ultimate nitrogen-fixing plant organs are built. Nonetheless, important gaps with respect to pertinent knowledge still remain.

My thesis work has focused on deciphering the role of the SHORT INTERNODES/STYLISH (SHI/STY) transcription factor gene family during nodule formation in Lotus japonicus, a model legume plant. I show here that the SHI/STY …

Structure/Function Analysis Of Fega And Fhua In Bradyrhizobium Sp., Alexander James Herd

Senior Honors Projects, 2010-2019

Bradyrhizobium japonicum is a Gram-negative soil bacterium commonly known for its agriculturally significant mutualistic relationship with soybean. In this symbiosis, the bacteria and plant undergo complex molecular signaling characterized by sent and received signals resulting in the formation of infection threads and root nodules. This research aimed to compare two related bacterial outer membrane proteins, FegA and FhuA, associated with the molecular signaling between the bacteria and plant. Previous work has led to the hypothesis that the N-terminal domain (NTD) of FegA in B. japonicum is needed for a functional symbiosis to occur. Recombinant bacterial strains expressing altered FegA proteins …

Characterization Of The Bioluminescent Symbionts From Ceratioids Collected In The Gulf Of Mexico, Lindsay L. Freed

HCNSO Student Theses and Dissertations

Anglerfishes are easily one of the most popular deep-sea creatures due to their menacing appearance, extreme sexual dimorphism, parasitic mating approach, and eye catching bioluminescent lure. Unlike most bioluminescent fishes, which intrinsically generate light, female anglerfishes belonging to nine of the 11 families within the suborder Ceratioidei (deep-sea anglerfishes) have developed a symbiotic relationship with bioluminescent bacteria that are housed within the light organs. Previous molecular work had identified symbionts from two anglerfish species as novel and possibly unculturable taxa (Haygood et al., 1992), but nothing more has been revealed about the bioluminecent symbionts of ceratioids. As part of …

Devonian Stromatoporoid Interactions At The Falls Of The Ohio State Park, Clarksville, Indiana, Morgan Sierra Hall

Undergraduate Theses

Stromatoporoids are calcitic sponges that occurred in the fossil record from the Early Ordovician to Late Devonian period. These sponges interacted with other organisms, especially rugose and tabulate corals. Some corals appear to benefit from the rigidity of stromatoporoids in response to turbulent waters. Stromatoporoids and many corals went extinct during the Frasnian-Famennian crisis when paleoenvironmental parameters were shifting. Studying the relationships between these taxa may provide insight to their vulnerability during the extinction.

This research was performed at the Falls of the Ohio in Clarksville, Indiana. Organisms in the Coral Zone were studied using transect sampling. Each fossil along …

The Key Question In Symbiotic Nitrogen Fixation: How Does Host Maintain A Bacterial Symbiont?, Onur Oztas

Doctoral Dissertations

The fact that plants cannot use nitrogen in the gaseous form makes them dependent on the levels of usable nitrogen forms in the soil. Legumes overcome nitrogen limitation by entering a symbiotic association with rhizobia, soil bacteria that convert atmospheric nitrogen into usable ammonia. In root nodules, bacteria are internalized by host plant cells inside an intracellular compartment called the symbiosome where they morphologically differentiate into nitrogen-fixing forms by symbiosome-secreted host proteins. In this project, I explained the host proteins required to maintain bacterial symbionts and described their delivery to the symbiosome. I showed that the SYNTAXIN 132 (SYP132) gene …

Symbiosis With Nitrogen-Fixing Rhizobia Influences Plant Defense Strategy And Plant-Predator Interactions, Adrienne Louise Godschalx

Dissertations and Theses

As sessile organisms, plants evolved a plethora of defenses against their attackers. Given the role of plants as a primary food source for many organisms, plant defense has important implications for community ecology. Surprisingly, despite the potential to alter entire food webs and communities, the factors determining plant investment in defense are not well-understood, and are even less understood considering the numerous symbiotic interactions in the same plant. Legume-rhizobia symbioses engineer ecosystems by fixing nitrogen from the atmosphere in trade for plant photosynthates, yet connecting symbiotic resource exchange to food web interactions has yet to be established. Here I test …