Environmental Microbiology and Microbial Ecology Commons^™

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 …

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 …

Microbial Dimension Of Symbiosis And Dysbiosis In Fungus–Gardening Ants, Blake S. Bringhurst

Biology Theses

With symbiotic partners, the means by which a host obtain a symbiont influence the specificity between the host and the symbiont. One such system where symbiont specificity is seen to varying degrees is with higher attine ants. Higher attine ants have symbiotic relationships with the fungal cultivar they grow and the bacterial symbionts in their microbiomes. Among the higher attines, there are two broad groups of fungi. Most ants in the genus Trachymyrmex tend to grow Clade–B fungi, which are a group of undescribed Leucocoprinus species, while leaf–cutting ants in the genera Acromyrmex and Atta tend to grow Clade–A fungi …

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 …

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 …

Application Of A 14c-Assay To Assess Methanotrophic Biodegradation Of Tce In Low Ph Groundwater, Evan Groome

All Theses

Current biological strategies for remediating trichloroethylene (TCE) in low pH aquifers (i.e., pH14C-TCE assay was developed to determine pseudo first-order rate constants for the degradation of TCE in microcosms containing soil and groundwater from the Boeing Michigan Aeronautical Research Center (BOMARC) superfund site, where the pH ranges from 4.1 to 4.9. The ¹⁴C-TCE assay was also adapted to calculate soil-normalized rate constants for data from this site, as well as data that Szwast²¹ collected from the Beltsville Agricultural Research Center (BARC). In addition to natural attenuation, biostimulation through amendments of methane and nutrients were also assessed. This treatment …

Allelopathic Effect Of Cereal Straw Extracts On Growth Of Raphidocelis Subcapitata And Microcystis Aeruginosa, Holly Wren

Graduate Theses and Dissertations

Harmful algal blooms are increasing in size, duration, and intensity around the globe. For several decades, cereal straws have been recognized as a viable algal control method, though the mechanisms by which cereal straws inhibit algae remain a topic of research. The objectives of this study were to evaluate the effectiveness of decomposing cereal straw extract, particularly rice (Oryza sativa) and barley (Hordeum vulgare) straw extract, to inhibit the green alga Raphidocelis subcapitata or cyanobacteria Microcystis aeruginosa in bioassays and to determine if the effectiveness of decomposing rice straw extract is altered by the presence of natural organic matter or …

A Cross-Scale Nexus: Microbial Functional Genes In Tandem With Molecular-Level Nitrogen Fluxes And Implications For Field-Scale Biogeochemical Processes, Srusti Maddala

Graduate Theses and Dissertations

Nitrogen (N) biogeochemical cycling entails close networking between soil nutrients, plant species and resulting microbial communities, and abiotic factors such as temperature, moisture, and pH. To better understand transformations of N in soil microsites, which are known to be rich in N-cycling behavior, the microdialysis technique was employed to generate in situ data on temporal alterations of N during wetting-drying conditions in both the field and laboratory. The objectives were to 1) determine the lifespan of the microdialysis technique in field conditions, 2) evaluate the ability of the method to yield N fluxes that would be differential between the two …

Genomic Analysis And Characterization Of Surface Properties Of Naphthalene Degrading Acinetobacter Isolates, Gunn Emilie Berge

Graduate Theses and Dissertations (2019 - present)

No abstract provided.

Habitability, And Evolution Of Microorganisms Under Extreme Conditions, Azarin Yazdani

Graduate Theses and Dissertations

The choice of a solvent determines the possible biochemistry of life. Life on Earth is based on carbon biochemistry and has evolved in an environment with water as a solvent. As a polar solvent abundant on Earth, water has unique physical properties, including a large range of liquidity and low viscosity, making it a very good solvent for terrestrial life. Liquids other than water are abundant in the universe, and the chemical nature of these liquids might lead to different chemistries of life. In the first chapter, we review the main characteristics of a good solvent, and then we use …

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.

Analysis Of Geographic Variability Of Fecal Microbiomes Of Fratercula Arctica And Cross-Comparison Of Fecal Microbiomes Of Different Avian Feeding Types, Eric Jose Ramon Martinez

LSU Master's Theses

Gastrointestinal (gut) microbiota have a multitude of effects on their host, from aiding in digestion, to facilitating nutrient uptake, detoxification, and interactions with the immune system. Multiple factors have been identified that influence the composition of vertebrate microbiomes; these include host genetics, environmental conditions, diet and age, sex, and geography. However, broad inferences about wild avian gut microbial diversity and function under natural conditions are limited. Most knowledge on avian microbiomes is derived from studies on domestic poultry. Information on non-model taxa may provide important contextual information about vertebrate host-microbiome interactions and aid in future management of vulnerable species. Here, …

Tissue Decay Tested In Modern Metasequoia Leaves: Implications For Early Diagenesis Of Leaves In Fossil Lagerstätten, Caitlyn R. Witkowski, Qin Leng, Christopher W. Reid, Liang Feng, Hong Yang

Science and Technology Department Faculty Journal Articles

Sedimentary deposits yielding extraordinarily-preserved fossils (known as Lagerstätten) may provide significant insights into the physiology and environments of ancient plants, particularly when the fossils represent their original characteristics with limited diagenetic modifications. To better understand molecular, isotopic, and morphological changes during the early stages of diagenesis, degradation experiments were conducted in two time series: 1) a laboratory decay series using fungi on leaves over the course of a month and 2) a natural decay series with leaves collected from different stages of leaf senescence and early diagenesis. Both experiments used modern leaves of the dawn redwood Metasequoia glyptostroboides …

Molecular Identification Of Cryptococcus Neoformans Isolates From House Environments Of Hiv-Infected Patients In An Urban Area, Indonesia: A First Report, Machrumnizar Machrumnizar, Robiatul Adawiyah, Tjahjani Natriana, Darma Imran, Mohammad Muslim, Sjamsuridzal Wellyzar, Retno Wahyuningsih

Makara Journal of Science

Cryptococcus neoformans isolates were previously obtained from pigeon droppings in Jakarta. This study aimed to determine another source of infection and describe the supporting niche of the fungus. The occurrence of C. neoformans was evaluated in 110 samples of decaying wood and leaves, tree hollow debris, dust, and bird droppings. Yeasts isolates were collected from 22 houses of HIV-infected patients. The isolates were identified based on culture characteristics, an assimilation test, and URA5 restriction fragment length polymorphism polymerase chain reaction. The spatial analysis was conducted in geographical information system to determine dominant house and environmental factors. Seven of the 120 …

Analysis Of Soxs In S. Typhimurium By Transposon Mutagenesis, Joel Hanns, Brenda Pratte, Lon Chubiz Phd, Lauren Daugherty

Undergraduate Research Symposium

The mar-sox-rob regulon has been implicated in transcriptional regulation of several stress responses, such efflux of antibiotics, enzymes that break down reactive oxygen species, repression of biofilm formation, or repression of motility through downregulation of flagellar expression. This system is conserved among enteric bacteria and has been studied in species, such as E. coli and S. typhimurium. Some of these mechanisms can be costly and slow cell growth while increasing the probability of survival through tolerance of toxic environments. SoxS works in coordination with SoxR to respond to redox stress encountered by the cell. Interestingly, the overexpression of SoxS …

Biomass Estimation Of Marine Biofilms On Plastic Surfaces, Kian Banihashemi, Fernando Javier Gil

Biological Sciences

Plastics have become a major source of marine pollution, which threatens food safety and quality, human health, and marine ecosystems. Due to the drastic negative effects of plastics in a marine environment, alternative biodegradable plastics are being generated that are more eco-friendly and have less environmental impact. Though some of these plastics are known to biodegrade, the process of degradation for bioplastics has not been heavily studied in a marine environment. This pilot project sought to both quantify the process of biodegradation and compare across different methods for effectiveness of biomass estimation, which serves as an indicator of biodegradation. Plastics …

Discovering Novel Polyextremotolerant Fungi And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin C. Carr

School of Biological Sciences: Dissertations, Theses, and Student Research

The ecological niche of polyextremotolerant fungi within oligotrophic ecosystems such as biological soil crusts has not yet been determined. These fungi persist in locations where nutrients are depleted while simultaneously surrounded by autotrophic microbes such as algae and cyanobacteria. Yet it has not been shown that they are engaging in any exchange of nutrients the way lichens do. However, there is seemingly no other way for these fungi to obtain vital nutrients, such as carbon or nitrogen, other than from these microbes. Here we have isolated polyextremotolerant fungi from cold desert biological soil crusts which are a microbial biofilm that …