Student Publications and Presentations

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    The Effect of Fertilizers on Methanotrophic Microbes in Wetland Environments
    (2022-05-09) Thompson, Pierce; Marty, Harvill; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    Climate Change is perhaps the greatest threat to life on Earth. As anthropogenic carbon emissions increase, the amount of methane released from wetlands increases. To combat large amounts of methane that are produced each day, organic pathways in organisms help regulate the levels of methane in biological ecosystems. However, usage of fertilizer in agriculture continues to stunt this naturally occurring regulation. To measure the effect that fertilizer has on methanotrophic microbes in a wetland environment, methanotrophic methane oxidation was monitored weekly. Soil was added to fourteen jars and fertilizer was added to half of those jars. The jars were incubated for a week before each measurement, emulating tropical wetland conditions; this allowed for more measurable results. Methane concentration was determined using a gas chromatographer (GC). The results showed that jars which contained fertilizer produced a significantly greater amount of methane (p=0.0072) compared to the control jars. These results can be used to better understand the effects of methane on an environment with high amounts of fertilizer runoff.
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    Effect of Cell Binding Domain Mutation in the unc-52 Gene of C. elegans
    (2020-04-21) Croomes, Olineece; Bertoluzzi, Siena; Johnson, Emily; Marquez, Meagan; Tajudeen, Mariam; Qiu, Zhonggiang; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    Emily Johnson, Morenike Tajudeen, Meagan Marquez, Siena Bertoluzzi, Olineece Croomes 7/31/2019 Effect of a cell binding domain mutation in the unc-52 gene of C. elegans Caenorhabditis elegans provides a significant canvas for research due to their sequenced genome, recorded molecular pathways, simple structure and comparative systematic components useful in modeling human diseases. The unc-52 gene in Caenorhabditis elegans encodes a homologouge for the extracellular matrix proteoglycan perlecan. UNC-52 constitutes a structural basement membrane protein which plays an important role in myofilament organization, and a regulator of growth-factor signaling in the body wall muscle cells. To determine the phenotypic effect formed from the presence of unc-52 mutation, we utilized the CRISPR-Cas9 gene-editing technology to mutate the amino acid sequence of the unc-52 gene. We edited the cell-binding domain of unc-52 and produced RGE (arg-gly-glu) from RGD (arg-gly-asp). We injected 52 N2 worms, and successfully generated several homozygous alleles in the C. elegans where the RGD sequences had been transformed to RGE. C. elegans was observed after treatment, and successfully mutated genes produced severely paralyzed uncoordinated worms in the surviving phenotype specimens proceeding CRISPR-cas 9 gene editing. Previous experiments with the unc-52 gene have shown a number of different mutations causing frameshift mutations and nonsense mutations which have been lethal to the organism. The RGD sequence we aim to mutate has been shown to mediate interactions with cell-surface integrins, as well as function in the development of myofilament lattice assembly. A severe phenotypic defect arising from the mutated genes would prove specifically the importance of the RGD sequence in the development of the cytoskeleton and cellular interactions, as well as demonstrate a non-lethal mutant in the unc-52 gene.
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    Targeting RGD cell-binding motif of LAM-3 and its effects on ECM
    (2020-04-21) Nichols, Erika; Dinh,Kyle; Han, Mark; Lishewski, Matt; Root, Jessica; Taylor, Megan; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    Targeting RGD cell-binding motif of LAM-3 and its effects on ECM Kyle Dinh, Mark Han, Matt Lishewski, Erika Nichols, Jessica Root, Meg Taylor, Zhongqiang Qiu Baylor University Biology Dept. Laminin is a protein composed of α, β, and γ chains and is present in basement membrane ECM. lam-3 is an α subunit which is essential in the formation of the basement membrane. It is highly expressed in the cell surroundings of the alimentary, epithelial, excretory, muscular, and nervous tissues. Mutations in the LAM-3 of C. elegans may cause pathological conditions of improper cell adhesion, migration, and signal-receptor pathways. Integrins are the extracellular matrix receptors that facilitate bidirectional signaling at the membrane surface. The specificity of this ligand-receptor interaction is based upon specific characteristics of the cell binding motif. The RGD is a binding motif synthesized of a tripeptide including Arginine-Glycine-Aspartate. Mutations in the RGD binding site will result in obvious inhibition of cell binding to the protein. A mutant C. elegans strain containing RGD to RGE mutation in lam-3 gene has been created by injecting a CRISPR-Cas9 mutation specific to the RGD site. This mutation induced a change from aspartic acid (D) to glutamic acid (E). We injected forty-nine N2 C. elegans and obtained one positive homozygote clone verified with a single-worm PCR. Further confirmation will be conducted in the coming weeks with comparison by thrashing assays as well as DNA sequencing of the positive homozygotic mutant. The identification of this homozygotic phenotype may directly relate to the human ortholog of LAMA-2 and potential treatment of the human muscular dystrophy.
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    Characterization of Hemicentin in C. elegans
    (2020-04-21) Ahumada, Abraham; Haworth, Emma; Ross, Kylie; Sowinski, Halee; Antony, Keerthi; Myeongwoo, Lee; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    Characterization of Hemicentin in C. elegans Emma Haworth, Kylie Ross, Halee Sowinski, Keerthi Antony, Abraham Ahumada Department of Biology, Baylor University, One Bear Place 97388, Waco, TX 76798, U.S.A In the nematode, Caenorhabditis elegans, the him-4 gene linked to the X chromosome encodes hemicentin protein, a component of the extracellular matrix (ECM), which is characterized by 45 immunoglobulin repeats, and fibulin-like domains. The ECM is a three-dimensional network composed of proteins and sugars deposited outside of the cell. ECM proteins are typically large, glycosylated, and contain repeats and motifs for cell binding. Hemicentin is specifically present in the basement membrane (BM), a special sheet-like ECM, that plays an important role in cell migration and tissue attachment, and stability of mitotic germ cells. HIM-4 contains six RGD motifs, a protein sequence specific to the integrin binding receptor. In the following study, CRISPR gene editing was used to create mutations in him-4 at two of the six RGD sequences. These sequences were targeted to replace the D amino acid (Aspartic Acid) with the E amino acid (Glutamic Acid). This mutation in him-4 causes defective phenotypes related to cell binding. We have isolated several targeted animals with tissue fragility, suggesting that the RGD sequence is vital for the function of the protein; the gene editing may interfere with hemicentin binding to the integrin receptor. The disruption of the ECM causes improper attachment of the gonad BM to epithelial BM leading to the hemorrhaging of the gonads and the intestines in C. elegans. The observation of the hemorrhaging phenotype and the single-worm PCR will be used to detect CRISPR-induced homozygous alleles. This research may allow for further studies on gonad development and human orthologs of the hemicentin protein. The connection between the hemicentin protein and the ECM deformities may offer insight into diseases associated with tissue fragility.
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    Effects of Oxygen Concentration on Hemoglobin Analog Production in Chironomidae Larvae
    (2020-04-21) Sauer, Paige; Kumar, Devan; Wood, Zack; Harvill, Marty; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    This experiment was conducted to test whether varying the oxygen content of a Chironomidae larvae’s environment would result in a color change of the larvae, signifying a change in hemoglobin analog concentration. Three environmental conditions were tested: a hypoxic environment, a high oxygen environment, and a control environment of open gas exchange. 100 larvae were placed in each environment and were left in their containers for five days. Results were recorded by crushing 20 of the specimens, diluting them in water, centrifuging the mixture, and measuring the absorbance of the solution in a spectrophotometer. The findings showed that the Chironomidae larvae from the high oxygen environment were in fact lighter than the others, and the larvae from the low oxygen environment were the darkest. This data supports the hypothesis that varied oxygen concentration results in color change in Chironomidae larvae.
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    Effects of Environmental pH Change on Wetland Microbial Communities
    (2020-04-21) Massingill, Emily K.; Le, Andy M.; Wimberly, Ally M.; Harvill, Marty; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    The Waco Wetlands serves as a habitat to many different plant and animal species native to Waco while also acting as a source of bioremediation for the water flowing in from the North Bosque. Plants and microbes (such as bacteria) are responsible for filtering this water of unwanted chemicals. Bacterial proteins and enzymes perform best in certain pH conditions. Our objective is to find the optimal environmental pH for the Wetlands microbes. By finding the optimal environmental pH for these microbes, we can possibly, safely alter the pH of the Wetland water to make bioremediation by bacteria more efficient. The students will go about this by, first, obtaining pounds of soil samples and a few Liters of water from the Waco Wetlands. The Nitrogen Concentration and pH level of the Wetland water will be tested. Then, 5 different environments will be created in different containers (2 containers for each environment) varying in pH level. There will be a control environment with the pH of the Wetland water. There will be 2 different environments with a pH lower than the control and 2 with a pH higher than the control. Soil (containing microbes) will be added to each container and the Nitrogen level of each container will be tested. Record Nitrogen levels of each containers every week for the duration of the research project. The environments that showed the most drastic decrease in Nitrogen content will posses the optimal pH for these wetland microbes. This is due to the increased Nitrogen uptake by the bacteria and the increase in bacteria reproduction.
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    Genetic screening for suppressor mutation in Caenorhabditis elegans odr-3 mutants
    (2020-04-21) Carroll, Jacqueline; Badra, Anthony; Cantu, Analisa; Conway, Caitlyn; Diaz, Ashley; Gunderson, Annika; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    A suppressor mutation is a mutation that negates the effects of a different, separate mutation, facilitating a return to the wild-type phenotype. In this experiment, a suppressor mutation screen of a mutation of the odr-3 gene was conducted by observing the egg-laying behaviors of mutagenized Caenorhabditis elegans worms in different chemical stimulants, and comparing the results to the wild-type. A mutant with a successful suppressor mutation of an odr-3 mutation will have similar egg laying behaviors to that of the wild-type (N2). The gene, odr-3, encodes a G protein α subunit that plays an integral role in sensory and olfactory neurons. The role odr-3 plays is vital to olfactory sensation, osmoregulation, and mechanosensory function. In this experiment, two worm lines that each had an odr-3 mutation and a potential suppressor mutation were generated, isolated, and tested: odr-3-JC-17 and odr-3-JC-66. When serotonin was introduced, the odr-3-JC-17 mutant strain showed a similar response in egg laying compared to the wild type, N2. The average number of eggs laid in an hour for each of the N2, odr-3, odr-3-JC-17 and odr-3-JC-66 strains in serotonin solution were 0.18 0.33, 0.21, and 0.44 eggs/hour, respectively. In dopamine solution, odr-3-JC-17 demonstrated similar egg laying behavior to N2. In a dopamine solution, the N2, odr-3, odr-3-JC-17 and odr-3-JC-66 strains laid 1.04, 2.25, 1.29, and 0.40 eggs/hour, respectively. When placed in an imipramine solution, odr-3-JC-17 had a significantly higher value of eggs laid in an hour than the odr-3 mutant. In imipramine solution, the N2, odr-3, odr-3-JC-17, odr-3-JC-66 mutant strains laid 1.56, 1.53, 2.80, and 0.91 eggs/hour, respectively. These results indicate the presence of a suppressor mutation that is at least partially effective in the odr-3-JC-17 mutant strain.
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    Isolation of the him-4 suppressor mutation which rescues the vitality of C. elegans
    (2020-04-21) Phipps, V.; Hartsfield, D.; Marsh, T.; Shalo, P.; Shields, B.; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    The nematode Caenorhabditis contains hemicentin, which is a protein that aids in gonad development, as well as tissue formation. The him-4 gene, associated with the production of hemicentin, was used to observe the effects of mutagenesis on C. elegans development and to isolate progeny that suppressed it. Five suppressors of him-4 (e1267) were isolated, and its phenotypes were compared to N2 (wild-type) and him-4. Phenotypic analyses revealed there had been a significant amount of suppression of the him-4 mutation. The results of the RNAi indicate some of the suppressors had an increased number of offspring when compared to him-4 mutants by the five suppressors. RNAi pat-3 and ina-1 indicated that some of the suppressors had an increased number of offspring when compared to the him-4 mutants. The overall results of the phenotypic assays, RNAi and hatch rates indicate some degree of suppression and seem to support the possibility of reversing the effects of him-4. Further research into the mechanisms of suppression and gene interaction, could result in significant information could then be applied to the human ortholog of hemicentin.
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    Effects of Cuticle Mutagenesis on C. elegans Osmoregulatory Behavior
    (2020-04-21) Ramani, S.; Houston, A.; Odell, H.; Smock, V.; Spivey, F.; Williams, T.; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    The cuticle of Caenorhabditis elegans plays a vital role in osmoregulation in stressed environments. While wild type C. elegans displays rapid deterioration in a hypertonic environment, certain mutant strains are hypothesized to elicit different responses to osmotic stress3. One such mutant is Dumpy (Dpy), which is characterized by a cuticle defect that produces short and fat worms with limited movement. The goal of this experiment was to analyze the effect of the Dpy mutation on osmoregulation by comparing the survivorship rates of N2 and Dpy strains of C. elegans when placed in a hypertonic environment. EMS mutagenesis was used to isolate populations of Dpy mutants, which were then exposed to .05 M, 0.1M, 0.25 M, 0.5 M, and 1.0 M NaCl for a 30 minute period. A survivorship assay was then conducted and results were compared to wild type survivorship within the different molarities. Dpy mutants were found to have consistently higher average rates of survival in higher molarity(>0.05M) solutions with a maximum difference of 4.2x in 0.5M. Further experimentation with this mutant can provide a molecular explanation of why the Dpy strain is able to resist more osmotic stress than N2 worms.
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    Genetic suppressors of str-2 serotonin response defects in Caenorhabditis elegans
    (2020-04-21) Kumar, Amy; Gakhar, Shiv; Harris, Julian; Story, Shelby; Vo, Henry; Vo, Bill; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    C. elegans, a nematode, is a model organism to study animal behavior and development. The genome of the C. elegans shows that there is a similarity between the genes of the nematode and that of humans. C. elegans are widely used because of its rapid life cycle and its small size which makes it easy for laboratory cultivation. The str-2 gene in C. elegans is predicted to be responsible for receptor activity linked to olfactory responses. Through the binding of odorants on specific olfactory receptors, str-2 allows them to detect pheromones, environmental threats, and nutrition—essentially playing a vital role in their behavioral functioning. The egg-laying behavior of C. elegans is regulated by its surroundings and can be activated or inactivated through various environmental cues. However, without a properly functioning olfactory system, we hypothesize that C. elegans will be unable to initiate standard egg-laying activity through its inability to pick up on these environmental cues—even if they are in the presence of serotonin. In this study, we created a mutagenized str-2 C. elegans that was induced by ethyl methanesulfonate (EMS) which would also be resistant to the egg-laying ability response to serotonin. The C. elegans were treated and screened to ensure that they represented their ability to lay the least eggs in response to serotonin. Egg laying assays were repeated until the offspring was uniform. We found that in the life cycle of the the str-2 mutants were found have a decreased life cycle compared to the non-mutants. These mutants had crippled olfactory responses to environmental transmitters, and lacked sensory abilities that hindered life. In addition, we found that the number of offspring produced by the mutants were significantly less than those of the non-mutants.
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    Genetic suppressor of che-3 serotonin response defects
    (2020-04-21) Kirsch, Lauren; Chaudhury, Tristin; Farlough, Catera; Gamayot, Jannine; Rodriguez, Grace; Weinberg, Savannah; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    che-3 is a cytosolic dynein heavy chain within Caenorhabditis elegans. This motor protein acts in intraflagellar transport and maintains structural integrity of sensory cilia structures. When mutated at the che-3 genetic locus, the mutants show progressive developmental defects of the chemosensory cilia. The che-3 mutants lose olfactory abilities and are unable to detect and respond to factors in their environment. Therefore, che-3 cannot respond to serotonin stimulation properly. Normally, wild type (N2) C. elegans produce more eggs in the presence of serotonin. Our goal was to test the relationship between serotonin and the olfactory senses within C.elegans. It is not known why che-3 is less responsive to serotonin. To address this, we mutagenized che-3 and found a suppressor that recovers the mutant’s response to serotonin. We created various trials to test a che-3 mutant suppressor that produces more eggs in the presence of serotonin than the wild type. The mutagenized che-3 were bred to yield the recessive F2 generation and placed in serotonin solutions to observe the number of eggs produced. The experiment was repeated many times to yield a consistent outcome. The results that were observed in che-3 mutants, compared to the wild type, produced more eggs in the presence of serotonin when the suppressing mutation occurred. In the future, further testing of che-3 mutants could aid in our understanding of the human response to serotonin and the effects of serotonin uptake within human chemosensory structures in the brain.
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    Isolation of Mutant Caenorhabditis elegans ​Resistant to Integrin α Subunit Deficiency
    (2020-04-21) Johnson, Bryce; Battle, Rachel; Chavez, Boozaziel; Escamilla, Astrid; Smelser, Ashton; Lee, Myeongwoo; Baylor University. Dept. of Biology; Baylor University.; Baylor University. Dept. of Biology
    The ina-1-encoded integrin α subunit is essential to Caenorhabditis elegans development, due to its role in complex processes such as morphogenesis, neuron migration, and cell signaling. Studies have shown that when this gene is mutated, many larvae die, and the worms that do survive display inactivity and morphogenic defects. Specifically, α-integrins function within heterodimeric integral membrane proteins and facilitate cellular and organismal processes via interactions between the cell’s cytoskeleton and other cell surfaces and the extracellular matrix. Similar to C. elegans’ ina-1 gene, humans possess 18 ina-1 homologs (ITGA3, ITGA6, and ITGA7), which are integral to normal human development; defects in the human α-integrin genes are linked to congenital muscular dystrophy, epidermolysis bullosa and cancer. C. elegans are a model organism to better understand integrin subunits and their important roles in both nematode development and human disorders due to their small number of α- integrin genes, which simplifies their genetic analysis. In this study, we generated and isolated mutants C. elegans that suppressed the integrin subunit deficiency by treating them with ethyl methanesulfonate (EMS). Mutants expressing suppressor mutations were characterized by more successful development, viability, and movement. The phenotypes were analyzed, and the mutants displaying these characteristics were isolated and cultured to form a colony of worms that contained the suppressor mutation. In the future, we will genetically analyze the suppressors of ina-1 mutations to elucidate their genetic basis and their important implications in human homologs.
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    The Effects of pH on the Rate of Successful Egg Hatches in Aedes aegypti
    (2020-04-21) Ngo, Sean; Fang, Samuel; Harvill, Marty; Baylor University. Dept. of Biology; Baylor University; Baylor University. Dept. of Biology
    Aedes aegypti, a common species of mosquito, is the primary vector for many deadly diseases, such as yellow fever, Zika, chikungunya, and dengue fever. Considerable efforts have been made by public health advocates to educate property owners in vulnerable areas about the risks of leaving out artificial containers that can collect rainwater and become prime breeding grounds for Ae. aegypti. With rising CO2 levels in the atmosphere, the degree of rainwater acidification increases each year. This experiment therefore sought to determine if there was a correlation between solution pH and the rate of successful hatches in Ae. aegypti eggs. It was hypothesized that more neutral pHs would see the largest percentage of successful egg hatches, while hatch rates in more acidic or basic solutions would see a diminished percentage. To test this, 10-25 eggs laid from a single cohort of female Ae. aegypti were placed in five solutions of different pHs and the viability of the eggs was determined by counting the number of larvae in each solution after an hour. Finally, the data was analyzed using a simple linear regression in order to determine the correlation, if any, between the two variables. No statistical significance was found between pH and hatching viability of Aedes aegypti eggs. Further research would have to be done to make a conclusion on the effect of pH on the rate of hatching for Aedes aegypti in their natural environment.
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    Effects of VPA on Mutated C. elegans
    (2018-08-06) Phan, Quynh-An Ngoc; Munnangi, Kavya; Beattie, Hailey Cristina; Tran, Sean; Lee, Chi-Hung; Baylor University. Dept. of Biology.
    Valproic acid (VPA) is a generalized drug used to alleviate a broad range of conditions in humans such as bipolar disorders as well as Parkinson’s disease, epilepsy, and other neuromuscular diseases. The use of VPA in treatment of such diseases is due to its properties as a neurotransmitter inhibitor. In studies involving the N2 strain (wild type) of C. elegans, VPA has been shown to increase their lifespans through the regulation of insulin/IGF-1 growth factor signaling pathways. However, in humans, VPA can cause serious side effects, such as liver problems, bleeding, and a reduction in blood platelet count. In addition, VPA can decrease diacylglycerol (DAG) production and inhibit IP3 signaling in C. elegans, which results in the suppression of egg laying; the IP3 signaling pathway involves the release of calcium ions from endoplasmic reticulum into the intercellular matrix. In our study, we want to create a mutant of C. elegans resistant to these egg-laying inhibitory effects that VPA causes. The mutation in the experiment was induced by ethyl methanesulfonate (EMS). The mutants C. elegans were then bred and screened for their ability to reproduce when exposed to VPA. This procedure was performed and repeated until a generation of consistently VPA-resistant offspring was evident. The results of the project have positive implications for the future of VPAss use. If the induced mutations can be used to offset some of the negative side effects of VPA in C. elegans, then it may be worth researching possible ways to reduce the negative side effects that VPA causes in humans.
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    Induced Mutation in Caenorhabditis elegans Causes Dopamine Resistance
    (2018-08-06) Walker, Brody; Grewal, Amanpreet Singh; Grayson, Nicholas Kallas; Harris, Luke Reed; Diokpa, Chijindu; Aceves, Tatiana; Lee, Myeongwoo.; Baylor University. Dept. of Biology.
    In humans, drug addiction is linked to varying dependencies of dopamine levels in the brain. The neurotransmitter is involved in many behavioral mechanisms in animals and mediates the reward pathway. In C. elegans, one of the effects of dopamine is to inhibit motor neuron activity and create a basal slowing response in the N2 (wild types). As a result, egg-laying in wild types is inhibited. To induce egg laying, mutagenized C. elegans were created with EMS (ethyl methansulfonate) to potentially produce a dopamine resistant mutation. After mutagenesis, 334 nematodes were isolated and screened for egg laying behavior. Both wild type and mutant nematodes were exposed to M9 (control), dopamine, and L-dopa (dopamine precursor) solutions. After 1 hour of incubation in these conditions, quantitative analysis was performed to assess the amount of eggs produced. Using an ANOVA test, statistical significance (p<0.001) was found between the wild type and mutant groups both exposed to dopamine. This implies there has been an induced dopamine resistance. The precursor to dopamine, L-dopa, showed similar effects with regard to egg laying behavior. When the dopamine pathway in C. elegans is known, the gene or group of genes implicated for dopamine resistance can be determined. Once identified, a homologous gene in humans could be located and studied for similar drug-resistant effects. The knowledge gained from this research has implications in the fields of gene therapy and drug abuse.
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    The Influence of Imipramine on the Egg-Laying Behavior of Caenorhabditis elegans
    (2018-08-06) Alaniz, Alyssa; Valencia, Michael James; Hussain, Neha; Feese, Emily Ann; Luksch, Annie Sarah; Mancillas, Victoria Alexandra; Lee, Myeongwoo.; Baylor University. Dept. of Biology.
    Discovering new ways to treat mental disorders is at the forefront of scientific research due to their imposing challenges on worldwide health. A current drug therapy option is imipramine, marketed as Tofranil, a tricyclic antidepressant (TCA) used to treat mental disorders such as depression. TCA’s predominantly inhibit the reuptake of the neurotransmitter, serotonin. The effects of exogenous serotonin increases egg laying by stimulating vulva contractions within Caenorhabditis elegans. To determine the effect of imipramine, C. elegans were analyzed based on their important physiological process, egg laying. Wild-type (N2) C. elegans responded to imipramine by showing increased egg-laying behavior. In order to observe the phenotype of mutant C. elegans in imipramine, worms were treated with ethyl methanesulfonate (EMS) to induce point mutations. The desired recessive mutants (Strain A) were determined by those who laid the least amount of eggs in the liquid egg-laying assays of imipramine. Egg laying assays were also conducted in doxepin, serotonin, and control M9 solutions. Since doxepin is a TCA similar to imipramine, it had similar effects on Strain A mutants by also demonstrating a decrease in egg-laying behavior.
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    The Effect of Mutations in Toll-like Receptors on Caenorhabditis elegans Egg-Laying signaling
    (2018-08-06) Deande, Matthew Thomas; Hayashi, Merrick Max; Bougoulias, Michael; Smith, Brock David; Hilbig, Gabriel; Baylor University. Dept. of Biology.
    While many factors show to affect egg laying in C. elegans, we are interested in the downstream effects of Toll-like receptors (TLRs) and their impact on egg laying because a direct relationship is still unknown. Studies have shown the importance of TLRs in the innate immunity of C. elegans and their ability to prevent gram-negative bacterial growth by identification of a single gene for TLR, tol-1. We hypothesize that tol-1 deficient C. elegan mutants will display a reduction in egg laying compared to the wild-type, due to a hindrance in an unknown signal transduction cascade. Part of this pathway would include the C. elegans' response to serotonin, a neurotransmitter stimulating hermaphrodite specific motorneurons (HSN), playing a central role in up-regulation of egg-laying behavior. In this study, egg laying assays were performed on N2 wild-type and tol-1 deficient C. elegans in serotonin. Additionally, the tol-1-/- worms were exposed to EMS mutagenesis, furthering our study. Results show that these worms experienced an increase in egg laying in the F2 generation, overcoming their initial resistance. Further experiments can be performed to elucidate the mechanism by which tol-1 deficient C. elegans overcame this mutation allowing them to surpass the N2 in egg laying ability.