Environmental Microbiology and Microbial Ecology Commons^™

Rapid Bacterial And Fungal Successional Dynamics In First Year After Chaparral Wildfire, M. Fabiola Pulido-Chavez, James W. J. Randolph, Cassandra A. Zalman, Loralee Larios, Peter M. Homyak, Sydney I. Glassman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The rise in wildfire frequency and severity across the globe has increased interest in secondary succession. However, despite the role of soil microbial communities in controlling biogeochemical cycling and their role in the regeneration of post-fire vegetation, the lack of measurements immediately post-fire and at high temporal resolution has limited understanding of microbial secondary succession. To fill this knowledge gap, we sampled soils at 17, 25, 34, 67, 95, 131, 187, 286, and 376 days after a southern California wildfire in fire-adapted chaparral shrublands. We assessed bacterial and fungal biomass with qPCR of 16S and 18S and richness and composition …

The Expanding Marine Built Environment And Biofilm Formation Processes, Rachel Mugge

Dissertations

The marine built environment (i.e., places or things made or modified by humans) in the northern Gulf of Mexico is rapidly expanding and includes over 2,000 known historic shipwrecks, nearly 4,100 artificial reefs, and other built structures for natural resource extraction, marine aquaculture, renewable energy generation, munitions dumping areas, and commercial and recreational activities. While these structures have the potential to develop into artificial reefs, acting as biodiversity hotspots that provide food and shelter and facilitate organism transport, it is unclear how they affect biodiversity and ecosystem function in the marine environment. The success of artificial reefs to become ecosystems …

Guano Among Bat Species From Two Regions Shows Influence Of Geography And Diet On Bacterial Community, Rahma Ahmed, Thomas Mcelroy, Shannon Whitney, Lydia Moore

Symposium of Student Scholars

Studies of bat guano have shown that the diversity and structure of associated microbial communities can be related to factors such as host phylogeny, life history and reproductive stage, geography, and diet. Many insectivorous bat species in the southeastern U.S. have generalist diets that may shift seasonally to take advantage of abundant prey species or maximize caloric intake. Seasonal shifts in prey availability or consumption should be reflected in a guano microbiome change. We also expected to detect distinct guano microbiomes within species. Within species, distinct microbial communities related to geography, and finally life history and reproductive stage. We compared …

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban

Graduate Theses and Dissertations

Nitrogenase is the metalloenzyme only found in bacteria and archaea that is essential for biological nitrogen fixation (diazotrophy), but it can also serve as a catalyst in biofuel production. All diazotrophs contain a molybdenum (Mo) nitrogenase, while some species contain additional alternative nitrogenases where either vanadium (V) or iron (Fe) replace Mo in the active site cofactor. Nitrogen fixation by bacteria has been extensively studied. The limited investigation of nitrogen fixation in methanogenic archaea (methanogens) indicates production of nitrogenase is simpler than in bacteria and methanogen nitrogenase has different biochemical properties. Thus, methanogen nitrogenases provide a promising alternative for genetic …

Characterizing The Cutaneous Microbiome Of Eurycea Lucifuga As A Potential Defense Against Chytridiomycosis, Madeline Key

Senior Honors Theses

Chytridiomycosis is an emerging infectious disease that is significantly reducing global amphibian populations. The disease is caused by Batrachochytrium dendrobatidis (Bd), a fungus that lethally modifies amphibian skin. Recent research has suggested that the cutaneous microbiome of individual amphibians may play a role in susceptibility to the pathogen. In this study, twelve cave salamanders (Eurycea lucifuga) were collected. Cutaneous bacteria from each salamander were isolated and identified using Sanger Sequencing. Additionally, a Bd-challenge assay was performed to determine each isolate’s antifungal activity. Results indicated many microbial isolates possessed inhibitory capabilities against Bd, which may …

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, …

Combining Isotopic And Genetic Analyses To Quantify Microbial Facilitation Of Recalcitrant Resource Use By Terrestrial And Aquatic Consumers, Alexi Christina Besser

Biology ETDs

Quantifying the flow of energy and nutrients through food webs is foundational to understanding the structure and function of ecosystems. Here, I utilize the stable carbon and nitrogen isotope analysis of individual amino acids to trace the movement of essential amino acids through terrestrial and freshwater food webs in New Mexico, USA. I first explore isotopic patterns among co-occurring terrestrial plants and aquatic algae. I then combine this molecular isotopic approach with 16S and 18S rRNA sequencing to demonstrate the importance of gut microbiota as sources of essential amino acids to wild mammalian hosts. Next, I explore the roles of …

Algae And Cyanobacteria In The Aphotic Habitats Of Veternica Cave (Medvednica Mt., Croatia) And Selected Caves Of The Dinaric Karst (South-Eastern Europe), Najla Baković, Tanja Pipan, Robert Baković, Roman Ozimec, Josip Rubinić, Renata Matoničkin Kepčija

International Journal of Speleology

Microphototrophs (algae and cyanobacteria) in karst environments have been intensively studied in aquatic epigean habitats. In recent decades knowledge about the communities inhabiting cave entrances and lampenflora has grown substantially, but the data about the communities in aphotic cave zone are scarce. This study aimed to investigate spatio-temporal presence of microphototrophs in the aphotic zone of Veternica Cave (Mt. Medvednica karst) and to present additional preliminary data from 22 caves of the Dinaric karst. The data were collected over ten years, in parallel with research on cave phagotrophic protists. In addition to the remains of microphototrophs, living algae and cyanobacteria …

The Presence Of Microcystin In The Northwest Indiana Watershed, Breeann Mild

The Journal of Purdue Undergraduate Research

No abstract provided.

Occurrence Of Kanamycin-Resistant Bacteria Relative To Anthropogenic Pollution Along Richland Creek In Nashville, Tn​, Jolene Ho Mach, Annie Le, Brandon Torres Ramirez

Science University Research Symposium (SURS)

The overuse of antibiotics has caused an increase in antibiotic-resistant (AR) bacteria, which is a serious public health concern. Previous studies showed a significant correlation between anthropogenic pollution and AR bacteria. This project aims to identify AR bacteria in Richland Creek relative to local anthropogenic pollution. Water samples were collected at four locations along Richland Creek in Nashville, Tennessee. Bacteria resistant to the antibiotic kanamycin were isolated from the water samples, identified to genera using DNA barcoding, and compared among the sites. We expect to see a greater abundance and diversity of kanamycin-resistant bacteria closer to the end than near …

Simple Organic Fertilizer Amendments For Farming In Degraded Soils: Effects On Plant-Microbe Interactions, Andrew Adamski

All NMU Master's Theses

The rapid loss of topsoil, biodiversity, and water quality across agricultural land in the United States and the industrialized world poses some of the most important risks to the future of global and domestic food security. Not only is arable land being lost at an unsustainable pace, but the average age of farmers has also steadily been rising due to a myriad of barriers young, BIPOC (Black, Indigenous, and People of Color), and beginning farmers face. In an attempt to address these issues, worm castings, bokashi tea, fish hydrolysate, and biochar were applied alone and in combination to an extremely …

Towards More Complete Metagenomic Analyses Through Circularized Genomes And Conjugative Elements, Benjamin R. Joris

Electronic Thesis and Dissertation Repository

Advancements in sequencing technologies have revolutionized biological sciences and led to the emergence of a number of fields of research. One such field of research is metagenomics, which is the study of the genomic content of complex communities of bacteria. The goal of this thesis was to contribute computational methodology that can maximize the data generated in these studies and to apply these protocols human and environmental metagenomic samples.

Standard metagenomic analyses include a step for binning of assembled contigs, which has previously been shown to exclude mobile genetic elements, and I demonstrated that this phenomenon extends to all conjugative …

Consequences Of Biofilm Architecture On Vibrio Cholerae Ecology And Life History, Benjamin Ray Wucher

Dartmouth College Ph.D Dissertations

The diversity of microbes and the environments they inhabit are staggering. In many of these environments, bacteria have evolved to form sessile surface attached communities called biofilms. These biofilms have wide reaching impacts from importance in global carbon cycling, to persistent catheter infections, to biofouling and wastewater treatment. While many species of microbes form biofilms to survive in their environment, the architectures of these structures vary widely between organisms. Even though a great deal of work has been done to understand bacterial communities and their functions, little work has examined how the spatial aspects of biofilm architecture can affect the …

Exploring The Use Of Covellite As A Proxy For Corrosion Of Native Copper By Sulphur Reducing Bacteria, Manan K. Joshi

Undergraduate Student Research Internships Conference

We are analyzing the effect of sulphate reducing bacteria on native copper, and using that evidence to further support the initiative of having a deep geological repository to store nuclear material. Sulphate reducing bacteria are a concern for the deep geological repository as they cause the corrosion of regular copper. However native copper has gone billions of years without corrosion, which could either mean that it had not been exposed to sulphate reducing bacteria over the billions of years, or native copper is able to withstand corrosion despite the contact of sulphate reducing bacteria. We can find out by trying …

Novel Signal Sequences And Fusion Partners For Paratransgenesis In Asaia, Christina Grogan

Electronic Theses and Dissertations

Mosquitoes transmit many pathogens that cause human disease. One such disease, malaria, is caused by parasites in the genus Plasmodium, infecting over 200 million people and killing over 600,000 per year. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance. Research has turned to additional and novel methods of control, such as altering the microbiota of the vectors. In this method, called paratransgenesis, symbiotic bacteria are genetically modified to affect the mosquito’s phenotype by engineering them to deliver antiplasmodial molecules into the midgut to kill parasites. These molecules must be released by the …

Effects Of Mass Death On Community Structure And Ecosystem Function, Abby Kimpton Jones

Theses and Dissertations

Death and decomposition are natural processes that are generally well-understood. However, large events of death, such as mass mortality events (MMEs) are increasing in frequency and their impacts on the ecosystem are largely unknown. These events may have both bottom-up effects from increased nutrient input as well as top-down effects from loss of an ecological functional group by the affected population. Different functional MMEs may result in different top-down effects, creating cascading effects. In Chapter 1, I test the hypothesis that scavenger and herbivore simulated MMEs generate novel bottom-up and top-down effects. Results indicate that MMEs have a significant effect …

Genome Sequence Of Sn1, A Bacteriophage That Infects Sphaerotilus Natans And Pseudomonas Aeruginosa, K.M. Damitha Gunathilake, Denise M. Tremblay, Pier-Luc Plante, Ellen Jensen, Kenneth Nickerson, Sylvain Moineau

Kenneth Nickerson Papers

Phage SN1 infects Sphaerotilus natans and Pseudomonas aeruginosa strains. Its genome consists of 61,858 bp (64.3% GC) and 89 genes, including 32 with predicted functions. SN1 genome is very similar to Pseudomonas phage M6, which contains hypermodified thymidines. Genome analyses revealed similar base-modifying genes as those found in M6.

Phage SN1 was isolated in 1979 from activated sludge samples obtained from a wastewater treatment plant (Lincoln, Nebraska, USA) using S. natans ATCC 13338 as the host (1, 2). An early study showed that the siphophage SN1 has unusual bases in its genome as confirmed by cellulose thin-layer chromatography (1). Its …

An Investigation Of Intrinsic And Extrinsic Factors That Influence Soil Microbial Succession During Human Decomposition, Allison R. Mason

Doctoral Dissertations

Decomposer organisms play a vital role in terrestrial nutrient cycling, breaking down complex organic compounds and providing nutrients for primary producers. Microbial communities and other decomposers associated with a vertebrate carcass, or the “necrobiome”, are critical for degradation and recycling of soft tissues following vertebrate mortality. The impact of microbial decomposers in vertebrate decomposition has been shown with regard to soil microbial communities, where the presence of soil microbes impact decomposition rate and undergo succession. However, current assessments of microbial ecology within decomposition-impacted soils have primarily focused on one aspect of microbial succession: succession of bacterial taxa for forensic applications. …

Microplastics In Freshly Fallen Snow: How May It Adversely Impact Human Health And Exacerbate The Covid-19 Crisis?, Ayesha Liaquat, Aleena Kashif, Sushma Rathi, Alishba Raza

Medical College Documents

No abstract provided.

Functional Characterization Of Mycobacterium Smegmatis Phage Moomoo Gene Products: Identification Of Toxic Genes, Whitney Heard

Masters Theses & Specialist Projects

Mycobacteriophages are a group of phages that infect members of the genus Mycobacteria. Previous studies have conducted extensive comparisons of the mycobacteriophage genomes and amino acid sequences to establish different phage families. MooMoo is a singleton mycobacteriophage that has been characterized due to its lack of appreciable homology to other phages. Some of its unique properties include its structure and the isolation of a mutant that causes clear plaque phenotypes. The experiments described in this thesis identified three MooMoo phage (gp87, gp90, and gp91) encoded proteins that are toxic to the bacterial host, Mycobacterium smegmatis.Through the use of a …