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Bdellovibrio bacteriovorus is a predatory bacterium that may serve as a living antibiotic by destroying biofilms and invading gram-negative bacteria. Swimming at over 100μm s-1, these predators collide into their prey and invade them to complete their life cycle. While previous experiments have investigated B. bacteriovorus’ motility, no study has

Bdellovibrio bacteriovorus is a predatory bacterium that may serve as a living antibiotic by destroying biofilms and invading gram-negative bacteria. Swimming at over 100μm s-1, these predators collide into their prey and invade them to complete their life cycle. While previous experiments have investigated B. bacteriovorus’ motility, no study has yet collected swim speed variations over the lifespan of B. bacteriovorus. In this study, we used state-of-the-art bacterial tracking methods to record the speed of tens of thousands of bacteria. These results were used to describe their metabolic state under starvation conditions in which they lose energy in a dissipative manner by propelling themselves at high speeds through solution. In particular, we investigated the metabolic response of starved predators to the addition of prey-lysate.
ContributorsCarlson, Mikayla Lynn (Co-author) / David, Rowland (Co-author) / Presse, Steve (Thesis director) / Gile, Gillian (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
The termite Coptotermes gestroi is a small subterranean termite originating from Southeast Asia. The hindgut of C. gestroi contains five distinct species of parabasalid: Pseudotrichonympha leei, two undescribed species from the genus Holomastigotoides, and two undescribed species from the genus Cononympha. This study investigates the protist symbionts in C. gestroi

The termite Coptotermes gestroi is a small subterranean termite originating from Southeast Asia. The hindgut of C. gestroi contains five distinct species of parabasalid: Pseudotrichonympha leei, two undescribed species from the genus Holomastigotoides, and two undescribed species from the genus Cononympha. This study investigates the protist symbionts in C. gestroi and the relationship between their relative abundance as inferred by Illumina sequence reads and the directly observed abundances for each protist genus. Illumina amplicon sequencing as a means of DNA analysis is a proven method for identification and diversity analysis, although the specific ratios of sequence reads to cell abundance in protists is not well known. In this study, protist communities were observed under light microscopy; cells were counted under hemocytometer and characterized at the molecular level using Illumina amplicon sequencing. When comparing sequence read abundances to cell abundances, some general trends were found in both analysis methods. Cononmypha repeatedly formed the majority of the community, while Holomastigotoides and Pseudotrichonympha were responsible for a smaller yet similar portion of the population. Cell counts and sequence reads were also compared using an assumed linear model, with R2 values generated to quantify the relationship between both. The results suggest that Illumina sequencing can be used to obtain rough estimates of community diversity, but the high variability within the data suggest that the read abundances should be treated with caution.
ContributorsAvilucea, Erin L. (Author) / Gile, Gillian (Thesis director) / DeMartini, Francesca (Committee member) / Taerum, Stephen Joshua (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
The termite Zootermopsis nevadensis nuttingi, which is located in coastal forests of the western United States, plays an important ecological role in the breakdown and digestion of wood. Vital to this role are symbiotic protists residing in the termite's hindgut. Five protist genera of varying size and morphology make u

The termite Zootermopsis nevadensis nuttingi, which is located in coastal forests of the western United States, plays an important ecological role in the breakdown and digestion of wood. Vital to this role are symbiotic protists residing in the termite's hindgut. Five protist genera of varying size and morphology make up this gut community. Despite years of study on this termite species, little was known about the spatial organization of the protist community within Zootermopsis nevadensis nuttingi. To resolve this issue, a study was conducted in which the distribution of protist genera among gut segments was observed and elucidated. This was done by separating hindgut segments, then counting the protists using a hemocytometer at a magnification of 200x. 60 segments from 20 termites were examined, and the total number of protists counted was 69,560. Images were also taken using a scanning electron microscope. Statistically significant, distinct distribution patterns were found for Trichonympha, Trichomitopsis and Streblomastix, while the small genera of Hexamastix and Tricercomitus appeared to have no special distribution. Trichomitopsis was more abundant in the posterior hindgut, Streblomastix was more abundant anteriorly, while the distribution of Trichonympha varied by colony. Hexamastix and Tricercomitus make up a large majority of the protists observed in any segment, followed by Streblomastix, Trichomitopsis and Trichonympha. Understanding the distribution of different protists within the hindgut may improve our understanding of the ecological relationships among protists as well as their individual roles in lignocellulose digestion, contributing to a better understanding of the hindgut system as a whole.
ContributorsPiarowski, Christina Marie (Author) / Gile, Gillian (Thesis director) / DeMartini, Francesca (Committee member) / Taerum, Stephen (Committee member) / School of International Letters and Cultures (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15 years, new research has provided a link between the environmental

Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15 years, new research has provided a link between the environmental and clinical spheres of antibiotic use. This data suggests that environmental bacteria, particularly those found in livestock farming ecosystems, may significantly contribute to the overall flow of antibiotic resistance genes into human populations. The main force behind this is the utilization of antibiotics as growth promoters in animal feed supplements, seeding individual animals and their surroundings with low doses of antibiotics. Notable increases in resistance have been observed within areas that utilize these supplements, as well as in connected but unrelated systems. Waste management strategies are poorly implemented, leading to the dispersal of contaminated runoff into groundwater and riverine environments. Furthermore, existing waste processing is limited in efficacy, often releasing large amounts of unprocessed antibiotics as well as a concentrated population of resistant bacteria. Within these resistant populations, horizontal gene transfer has emerged as a vehicle for the distribution of resistance genes into other populations of bacteria. Due to the prevalence of these transfer events, a new role for the environment as a reservoir and incubator of resistance genes is proposed. Current strategies for managing the spread of antibiotic resistance are woefully inadequate, and the continued emergence of new resistance mechanisms due to negligence highlights the need for global, multidisciplinary solutions. To corral the spread of antibiotic resistance, a system is proposed that utilizes metagenomic monitoring and the enforcement of core global policies to slow the advance of resistance while waiting for novel treatment strategies to bear fruit.
ContributorsHrkal, Jacob (Author) / Gile, Gillian (Thesis director) / Shi, Yixin (Committee member) / Sarno, Analissa (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description

Hundreds of thousands of people die annually from malaria; a protozoan of the genus Plasmodium is responsible for this mortality. The Plasmodium parasite undergoes several life stages within the mosquito vector, the transition between which require passage across the lumen of the mosquito midgut. It has been observed that in

Hundreds of thousands of people die annually from malaria; a protozoan of the genus Plasmodium is responsible for this mortality. The Plasmodium parasite undergoes several life stages within the mosquito vector, the transition between which require passage across the lumen of the mosquito midgut. It has been observed that in about 15% of parasites that develop ookinetes in the mosquito abdomen, sporozoites never develop in the salivary glands, indicating that passage across the midgut lumen is a significant barrier in parasite development (Gamage-Mendis et al., 1993). We aim to investigate a possible correlation between passage through the midgut lumen and drug-resistance trends in Plasmodium falciparum parasites. This study contains a total of 1024 Anopheles mosquitoes: 187 Anopheles gambiae and 837 Anopheles funestus samples collected in high malaria transmission areas of Mozambique between March and June of 2016. Sanger sequencing will be used to determine the prevalence of known resistance alleles for anti-malarial drugs: chloroquine resistance transporter (pfcrt), multidrug resistance (pfmdr1) gene, dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr). We compare prevalence of resistance between abdomen and head/thorax in order to determine whether drug resistant parasites are disproportionately hindered during their passage through the midgut lumen. A statistically significant difference between resistance alleles in the two studied body sections supports the efficacy of new anti-malarial gene surveillance strategies in areas of high malaria transmission.

ContributorsPhillips, Keeley Isabella (Author) / Huijben, Silvie (Thesis director) / Gile, Gillian (Committee member) / Young, Steven (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
ContributorsPerkins, Caitlin (Author) / Jacobs, Bertram (Thesis director) / Gile, Gillian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2023-05
ContributorsPerkins, Caitlin (Author) / Jacobs, Bertram (Thesis director) / Gile, Gillian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2023-05
Description

Oxymonas is a genus of Oxymonad protist found in the hindgut of drywood termites (family Kalotermitidae). Many genera of drywood termites are invasive pests globally. The hindgut microbiome of Cryptotermes brevis, the West Indian drywood termite, has not been described in detail, and only one published sequence exists of Oxymonas

Oxymonas is a genus of Oxymonad protist found in the hindgut of drywood termites (family Kalotermitidae). Many genera of drywood termites are invasive pests globally. The hindgut microbiome of Cryptotermes brevis, the West Indian drywood termite, has not been described in detail, and only one published sequence exists of Oxymonas from C. brevis. This study aims to analyze Oxymonas sequences in C. brevis from whole gut genetic material, as well as to dissect its place in phylogenetic trees of Oxymonas and how it fits into specific and evolutionary patterns. To amplify the 18S rRNA gene Oxymonas from C. brevis, the MasterPure DNA extraction kit was used, followed by PCR amplification, followed by agarose gel electrophoresis, followed by purification of the resulting gel bands, followed by ligation/transformation on to an LB agar plate, followed by cloning the resulting bacterial colonies, and topped off by colony screening. The colony screening PCR products were then sequenced in the Genomics Core, assembled in Geneious, aligned and trimmed into a phylogenetic tree, along with several long-read amplicon sequences from Oxymonas in other drywood termites. All whole gut sequences and one amplicon from C. brevis formed a single clade, sharing an ancestor with a sister clade of Oxymonas sp. from C. cavifrons and Procryptotermes leewardensis, but the other long-read fell into its own clade in a different spot on the tree. It can be conjectured that the latter sequence was contaminated and that the C. brevis clones are a monophyletic group, a notion further corroborated by a distantly related clade featuring sequences from Cryptotermes dudleyi, which in turn has a sister taxon of Oxymonas clones from C. cavifrons and P. leewardensis, pointing toward a different kind of co-diversification of the hosts and symbionts rather than cospeciation.

ContributorsSharma, Noah (Author) / Gile, Gillian (Thesis director) / Shaffer, Zachary (Committee member) / Coots, Nicole (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2023-05
Description

The symbiosis between termites and their parabasalid hindgut protists centers around the wood digestion that is needed for both species to acquire the nutrients from wood. One of the important carbohydrate-active proteins required for the wood breakdown are glycoside hydrolase (GH) families. Previous studies have looked at the phylogeny of

The symbiosis between termites and their parabasalid hindgut protists centers around the wood digestion that is needed for both species to acquire the nutrients from wood. One of the important carbohydrate-active proteins required for the wood breakdown are glycoside hydrolase (GH) families. Previous studies have looked at the phylogeny of some of these protein families from a termite whole gut transcriptome or in a different context than lignocellulose digestion. In this study, we attempt to understand the function and evolution of these GH families in the context of protist evolution by using protist single cell transcriptomes. 14 families of interest were chosen to create phylogenetic trees: GH2, GH3, GH5, GH7, GH8, GH9, GH10, GH11, GH26, GH43, GH45, GH55, GH67, GH95 for their interesting expressions across different protists such as being present in all protists or being present in only termite-associated protists. The dbCAN2 (automated Carbohydrate-active enzyme ANnotation) program was used to find GH families in each of the protist single cell transcriptomes and additional characterized sequences registered on the National Center for Biotechnology Information to create phylogenetic trees for each of the GH families of interest. Results show that many of the GH families expressed in protists were acquired through horizontal gene transfer from fungi and bacteria. Additionally, comparison to the parabasalid phylogeny indicates most GH families evolved independently from the protists. Based on the pattern of expression of these GH families throughout different protist orders, conclusions can be made about whether the specific family was vertically or horizontally acquired in the termite symbionts.

ContributorsJahan, Israa (Author) / Gile, Gillian (Thesis director) / Wang, Xuan (Committee member) / Swichtenberg, Kali (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Psychology (Contributor)
Created2023-05
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Description

Nonsense mediated decay is a pathway that selectively degrades mRNAs that contain premature termination codons (PTCs). The purpose of this study is to research the evolution of NMD in Parabasalia and infer whether they have a normal, functioning nonsense-mediated decay pathway. Parabasalia are single-celled, flagellated protists that have undergone evolutionary

Nonsense mediated decay is a pathway that selectively degrades mRNAs that contain premature termination codons (PTCs). The purpose of this study is to research the evolution of NMD in Parabasalia and infer whether they have a normal, functioning nonsense-mediated decay pathway. Parabasalia are single-celled, flagellated protists that have undergone evolutionary transitions as they become obligate symbionts of termites. The key proteins involved in nonsense-mediated decay, ATM, ATR, UPF1, SMG1, UPF2, UPF3A, UPF3B, were researched and used in order to build phylogenetic trees to analyze what other species of eukaryotes have these same genes and where they branch relative to the nonsense mediated decay proteins present in Parabasalia. The main question being asked in this research is if Parabasalia have enough of the main nonsense mediated decay proteins to have a functional nonsense-mediated decay process and if not, which proteins have been lost over evolutionary history. To carry out this research, phylogenic trees were built using transcriptomes from many different types of eukaryotes that contained the main proteins involved in the nonsense-mediated decay pathway. These transcriptomes were taken from the National Center for Biotechnology Information (NCBI) database using the BLAST algorithm, trimmed using TrimAl, aligned by utilizing AliView which utilizes Muscle. Sequoia was then used to remove redundant species from the trees, and IQ-TREE was used to form the phylogenic trees. This process was repeated four times to create well-rounded trees with various eukaryotic species present. The results of this research found that ATM, ATR, UPF1, SMG1, and UPF2 are present in Parabasalia as well as across many eukaryotic groups, whereas UPF3A and UPF3B were not found in many of the eukaryotes researched. This points to Parabasalia having a normal and functioning nonsense-mediated decay pathway as they have the majority of the essential proteins needed for a functional pathway.

ContributorsHammond, Emma (Author) / Gile, Gillian (Thesis director) / DeVecchio, Duane (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2022-05