Undergraduate and graduate student presentations from the School of Biological Sciences, 2021 Online University Research Symposium, Illinois State University
Do ISU Students Differ From Other Universities' Students In Their Social Distancing Behaviors, Experience With Covid-19, Trust In Science, And Vaccination Intention?
College students are an important population to consider when trying to slow the COVID-19 pandemic. While young people display less serious symptoms of the infection, their tendency to have asymptomatic infections increases risk to campus and surrounding comminities. The goal of WhiV VWXd\ ZaV Wo XnderVWand hoZ IllinoiV SWaWe UniYerViW\ VWXdenWV¶ social distancing behaviors and beliefs about the COVID-19 pandemic differed from that of students at other colleges/universities. We administered a nationwide survey that asked about social distancing practices, experience with COVID-19, amount of trust in science and likelihood to receive the COVID-19 vaccination. This poster presents findings to four research questions: 1) Do ISU students differ from non-ISU students in their social distancing practices? 2) Do ISU students differ from non-ISU students in their experience with COVID-19? 3) Do ISU students differ from non-ISU students regarding their trust in science? 4) Do ISU students differ from non-ISU students regarding their likelihood of receiving the COVID-19 vaccine? We conclude that ISU students practice social distancing more than non-ISU students, ISU students have had more experience with COVID-19 than non-ISU students, ISU students trust in science more than non-ISU students and ISU students are more likely to get the COVID-19 vaccination than nonISU students.
Many species of organisms can sense and orient to the earth’s magnetic field. While the existence of this magnetic sense is widely accepted, little is known about the molecular and cellular mechanisms of magnetoreception. One favored mechanism involves magnetic particles that are capable of exerting force on adjacent mechanoreceptors when pulled by the force of the earth’s magnetic field. Evidence of magnetic particles has been reported in magnetotactic animals including C. elegans. We have previously discovered that AFD neurons play an important role in C. elegans magnetotactic behavior. However, it remains poorly understood how AFD neurons detect magnetic fields. Preliminary data from our lab have shown that some iron-handling proteins are required for normal magnetic orientation. We will be investigating the pattern of expression of these iron-handling proteins in C. elegans and if they are expressed near the AFD and AMsh. The results from this study could open a new research direction to the better understanding of mechanisms of in animals.
Peptide Neuromodulation Supports Temperature-Robust Neuronal Activity by Increasing Dendritic Electrical Spread
Acute temperature changes can disrupt neuronal activity, leading to loss of motor control and failure of vital behaviors. Acute warming of the isolated crab stomatogastric nervous system from 10°C to 13°C disrupts the rhythmic neuronal activity underlying mastication by silencing an important motor neuron, the Lateral Gastric neuron (LG). The disruption of activity in response to a 3°C temperature increase contrasts with observations that in vivo the same neuron is active after the temperature has increased b even more than 10°C. It was recently discovered that peptide neuromodulation present in vivo but not in vitro restores LG’s rhythmic activity and thereby allows the animal to sustain its ability to chew over a large temperature range. This effect could be replicated in vitro if the peptide neuromodulator was augmented experimentally. Neuronal activity depends on adequate signal spread throughout the dendrites - a process sensitive to shunting when ion channel conductances increase. We hypothesize that warming leads to an overall increase in membrane shunt, which disrupts rhythmic activity in LG by reducing signal spread in the dendrites. However, peptide neuromodulation restores LG’s rhythmic activity by counterbalancing the membrane shunt and reinstating the signal spread necessary for neuronal activity. To test these hypotheses, we quantified signal spread in LG’s dendrites while increasing the temperature from 10°C to 13°C, and applying the neuropeptide, Cancer borealis tachykinin-related peptide Ia (CabTRP Ia). We used two approaches to quantify signal spread; fluorescent Calcium imaging and two-electrode current- and voltage-clamp. We found that membrane shunt increased and signal spread decreased as the system warmed, but was reversed in the presence of CabTRP Ia. Our results indicate that peptide neuromodulation restores neuronal activity at warmer temperatures by increasing signal spread and opposing membrane shunt in the dendrites. CabTRP Ia activates an NMDA-like current called the modulator-induced current (IMI). To assess whether IMI increased LG’s temperature robustness, we introduced IMI into LG using a computer-brain interface. We found that introducing IMI at 13°C was sufficient to increase signal spread in the dendrites and restore LG’s rhythmic activity. Altogether, our results indicate that peptide activation of an NMDA-like current increases signal spread in the dendrites to sustain neuronal activity during temperature changes.
This study focused on students at Illinois State University and their experience with the COVID19 pandemic. This was done by surveying undergraduate students with differing demographics at ISU. They were asked several questions on their backgrounds, including political affiliation, geographical location, and religious beliefs. They were also asked to report their practices in preventing the spread of COVID-19. With these data we aimed to explore the following research questions: 1) Does hometown community type affect one’s social distancing measures? 2) Does financial hardship affect social distancing measures? 3) Does experience with the disease influence how they socially distance? 4) What is the relationship between religiosity and trust in science? 5) Does trust in science correlate with plans to get vaccinated? 6) What is the relationship between socioeconomic status and trust in science? Generally speaking, socioeconomic status does not mediate ISU students’ experiences during the COVID-19 pandemic. However, students with more experience with COVID-19 exhibited poorer social distancing practices than those that had less experience
Animals often increase their investment in reproduction in response to a threat to their survival (e.g. an infection), a life history strategy known as terminal investment. The dynamic terminal investment threshold model proposes that the tendency of an individual to terminally invest depends on other factors that alter an individual’s residual reproductive value. Here, we test the dynamic terminal investment model in burying beetles, insects that bury small vertebrate carcasses as a source of food and that provide extensive biparental care. We injected males at two different ages with heat-killed bacteria and measured their reproductive effort, predicting that immune-challenged males would show a longer period of parental care, consume less of the carcass, and produce a greater number of larvae in the current reproductive attempt compared with control males. We further predicted that older males would be more likely to terminally invest than younger ones. Males, when challenged with heat-killed bacteria as virgins prior to their first reproductive attempt, did not terminally invest, whereas these same individuals when challenged in a subsequent reproductive bout produced a greater number of offspring. Older, immune-challenged individuals gained less mass during their time on the carcass than control males, suggesting that terminal investment was subsidized by their consuming less of the carcass than they might have otherwise done in the absence of an immune challenge, leaving more for their offspring to consume. We conclude, that the age-specific terminal investment shown by immune-challenged males in the current study supports the dynamic terminal investment model.
Cilia are cellular protrusions that are important for many actionsin the body. For instance, motile ciliary structures clear material from the upper airways via directional mucus flow across the respiratory epithelium. The assembly of cilia is coordinated with the cell cycle and is known as ciliogenesis. Intraflagellar transport (IFT) is essential for ciliogenesis and aids the maintenance and function of cilia. During this transport process, cellular cargoes are shuttled along the microtubules of the axoneme: Kinesin-2 (KIF3A/KIF3B/KAP) drives transport to the tip of the cilium and dynein-2 motors drive transport back to the cell body. Heterotrimeric kinesin-2 belongs to the super family of the kinesin motors and next to IFT also drives membrane organelle transport in the cytoplasm. Proteins generally undergo post-translational modifications like phosphorylation, glycosylation, ubiquitination, and methylation. These modificationsincrease the functional diversity of proteins and regulate their activity. Misregulation of any of these modifications can result in unphysiological functionality of the target protein. For example, Chaya and colleagues (EMBO J., 2014) generated a KIF3A mutant in which all eight potential serine and threonine phosphorylation sites in the tail domain of the protein were removed and this mutant was unable to drive ciliogenesis. These results demonstrate that KIF3A phosphorylation is important for the function of KIF3A. However, it is unknown which of the exact phosphorylation sites is necessary to drive ciliogenesis. I hypothesize that dephosphorylation of a specific residue will stop IFT, outlining my aim to delineate the function of specific phosphorylation site in the tail of KIF3A. Kinesins have high medical relevance, but for technical reasons, there are very few drugs that directly affect the activity of specific kinesins. My effort to contribute to the understanding of the effects of phosphorylation on kinesin-mediated processes on a molecular level may thus open new avenues for drug discovery and therapeutical intervention.
Lespedeza cuneata is an invasive, non-native species of bush clover that is invading prairies where the native Lespedeza capitata grows. Both species of bush clover are legumes, which are nitrogen fixers. Legumes and their senescent leaves (i.e., “litter”) are well known for increasing levels of available nitrogen in the soil. However, the exotic L. cuneata also produces tannins that reduce the rate of germination in some prairie plants. The purpose of this study was to clarify whether these compounds in the litter of the invasive species of bush clover deter early growth in its native competitors, and to determine whether litter of each species of legumes would increase growth of native prairie plants. To address the influences of L. cuneata, we tested whether the impact of L. cuneata litter on growth of prairie plants (Goldenrod and Wild Quinine) was consistent with the effect of toxic tannins or improved nitrogen supply. Each prairie plant was divided into three groups of different treatments: native litter, exotic litter, and a control group with no litter. The plants were measured for height weekly, and at 9 weeks harvested, dried, and weighed. Growth trajectories suggested litter treatment was affecting the two species. In the analysis of dry shoot mass, the effect of litter treatment was significant). Surprisingly, for both species of plants, the exotic treatment (L. cuneata) displayed the best growth of all groups involved in the study. Addition of L. cuneata litter increased final mass more than either the control or addition of L. capitata litter, and the control produced greater growth than native L. capitata litter. Goldenrod was significantly larger than wild quinine but the two species did not differ in their response to the litter treatment. Based on the statistical findings, both the Goldenrod and Wild Quinine exotic treatment groups responded with increased growth and increased mass when the opposite had been predicted. These results question assumptions about exotic species and indicate that L. cuneata, despite prior findings, may benefit some members of the prairie community.
While transitions between neuronal states are essential to cognitive and motor functions, they are less understood than the states themselves. Transitions often consist of irregular firing activity that computational models predict is chaotic, meaning that it is deterministic and sensitive to initial conditions. Previous work shows that neurons exhibit chaotic activity and that these levels of chaos can be reduced through network interactions, ultimately achieving stable network activity. This indicates that minimizing chaotic activity is desirable for neuronal network function. Therefore, we hypothesize that biological neurons possess mechanisms to reduce chaos during transitions.
To characterize the levels of chaos during transitions, we use a combined experimental and computational approach. In our experimental approach, we induce transitions in the well-characterized crustacean stomatogastric nervous system using the neuropeptide proctolin. In our model approach, we use the Huber-Braun single neuron model and implement the excitatory, depolarizing current that proctolin activates, IMI.
In agreement with previous studies, IMI in the model was sufficient to elicit transitions between stable activity states with chaos occurring between states. However, chaos was only observable when comparing individual models with distinct IMI values or when a time-dependent IMI was implemented for sufficiently long transition durations, i.e. time interval during which the transition takes place. Short transition durations did not exhibit chaos.
To test whether this was the case in the biological system, we synaptically isolated the lateral pyloric neuron (LP) and bath-applied proctolin. This increased firing rates and elicited rapid transitions from silent or arrhythmic spiking to bursting. We quantified the levels of chaos using Lyapunov exponents which measure how quickly a system becomes unpredictable. Although the system exhibited chaos throughout the transition, the levels of chaos did not change significantly during the transition itself. Taken together with the model results, this suggests that rapid neuronal transitions suppress increases in chaos.
To further explore how the history-dependence of neuromodulators affect chaotic transitions, we used dynamic clamp to inject discrete levels of IMI into LP, omitting the time-dependence of proctolin. Increasing IMI induced transitions from silent or arrhythmic to tonic. We found that the levels of chaos did not change significantly throughout this transition, possibly due to LP being unable to burst with IMI alone. To test this, we performed similar proctolin and dynamic clamp experiments with the inherently bursting pyloric dilator neuron (PD) of the pyloric circuit. We are currently analyzing the results of these experiments.
Duchenne muscular dystrophy (DMD) is a genetic disorder caused by loss of dystrophin, responsible for connecting actin to the sarcolemma and transferring force into the extracellular matrix. In humans, DMD presents at a young age, resulting in developmental delays, muscle necrosis, increased sarcoplasmic calcium, loss of ambulation, and early death. Current animal models do not model the severity of DMD without the addition of sensitizing mutations. Thus, it remains elusive if increased sarcoplasmic calcium observed in dystrophic muscles follows or leads the mechanical insults caused by the muscle’s disrupted contractile machinery. This knowledge has important implications for patients, as physiotherapeutic treatments may either help or exacerbate symptoms, depending on how dystrophic muscles differ from healthy ones.
We observe that sarcoplasmic calcium dysregulation in dys-1 worms precedes overt structural phenotypes and can be mitigated by silencing calmodulin. Recently, we showed that burrowing dystrophic (dys-1) worms recapitulate many salient phenotypes of DMD. Here, we report dys-1 worms display early pathogenesis and increased lethality. To learn how dystrophic musculature responds to altered physical activity, we cultivated dys-1 animals in environments requiring either high intensity or high frequency muscle exertion during locomotion. We find that several muscular parameters (such as size) improve with increased activity. However, longevity in dystrophic animals was negatively associated with muscular exertion regardless of the duration of the effort. The high degree of phenotypic conservation between dystrophic worms and humans provides a unique opportunity to gain insights into DMD’s underlying pathology and to assess potential treatment strategies.
Kinesin motor proteins are vitally important for many cellular functions such as mitosis, ciliogenesis, and transporting cellular cargo. Kinesins move various cargo along microtubules unidirectionally from the minus- to the plus-end of a microtubule. There are three structural features that make up a kinesin: the stalk, the motor, and tail domains. The motor domains directly bind to and walk along microtubules while the tail domains interact with the cargo. The protein’s stalk portion comprises coiled-coil segments that allow the motor to dimerize via alpha-helices interacting through hydrophobic forces. These rigid segments are interrupted by flexible hinges that allow the kinesin molecule to fold back on itself in the absence of cargo. In this state, parts of the stalk and the tail domains bind to and inhibit the motor domains in a process called autoinhibition. This prevents the motor from binding and moving along microtubules when no cargo is present to conserve energy. In our lab, we study kinesin-2 family motors, specifically, KIF3A/KIF3B. Some motors of the kinesin-2 family form heterodimers, which is a unique feature compared to all other motor proteins found in mammals which form homodimers. In this work, we aim to elucidate the function of individual coiled-coil domains in the stalk during autoinhibition. The precise location of the coil domains within the stalk is, however, not known. Available coiled-coil prediction programs such as DeepCoil and COILS Server are programmed to predict coiled-coil formation in homomultimers, complicating the prediction of coil domains in the heterodimeric KIF3A/KIF3B motor. To overcome this hurdle, we took a rational prediction approach. We used DeepCoil to obtain the probability of individual amino acids being involved in the coiled-coil formation, and mapped these probabilities onto a 3D atomic model of the motor stalk generated by the MODELLER algorithm. We then used rational matching by looking at the hydrophobicity of each amino acid in relation to the probability predicted by DeepCoil and used this information to assign the amino acids sequences to the most probable location for each coilcoiled segment. In agreement with the reported coil domain architecture of the closely related homodimeric kinesin KIF17, we found that KIF3A/KIF3B likely also forms three distinct coiledcoil stretches in its stalk. In future work, we plan to generate mutant kinesins in which each of the predicted coil domains is deleted separately and then use motor activity assays to assess the function of each coil domains in KIF3A/KIF3B autoinhibition.
Creepy Crawly Compensation: Examining the Costs of Ectoparasite-Induced Compensatory Growth in Late-Stage Nestlings
When normal growth rates are suppressed, organisms may undergo a rapid period of increased growth in order to match the physical requirements of a developmental benchmark. This compensatory growth, however, is not without its costs, which can have varying consequences. In nestlings, a major benchmark is that of fledging, which requires advanced physical maturation. In previous studies, compensatory growth and some of its associated costs have been shown in prefledging nestlings but fledging-aged nestlings and the costs they may have sustained needs further study. Here we examine the costs of compensatory growth in late-stage European starling (Sturnus vulgaris) nestlings under the developmental stress of ectoparasitic infestation. Nests were subjected to either the addition of Northern fowl mites (Ornithonyssus sylviarum) or ectoparasite reduction through use of the miticide Permethrin. We followed nestlings throughout development, and at 10 and 20 days of age, assessed structural growth and collected blood to determine hematological measures and corticosterone titers. On day 20, the day prior to when starlings typically leave their natal nest, their brains were harvested. Starlings under ectoparasitic conditions had significantly smaller wingspans, tarsus lengths, and bodyweights on day 10, but on day 20, structural growth was indistinguishable from nestlings in miticide treated nests – suggesting compensatory growth. While we have yet to assess hemoglobin and corticosterone levels, analyses show that brain weight and hematocrit were significantly lower in nests with ectoparasites on day 20, perhaps indicating the protection of necessary physical traits for fledging through compensatory growth at the cost of these less apparent attributes.
Purification, Biotinylation, and Testing of a Monoclonal Antibody to Identify B Cells in Trachemys Scripta, the Red-Eared Slider Turtle
Allison Mool, Hanna Paton, and Whitney Green
There is a shortage of research in reptile immunity which is further hampered by lack of reptile-specific reagents. Evidence suggests there are important differences between reptile and mammalian immune strategies and our laboratory is interested in reptile B cell development and function. Our undergraduate research project involved the preparation of a previously developed monoclonal antibody (HL673) that recognizes turtle light chain protein. To begin, culture supernatant from the HL673 mAb murine cell line was received and was applied to a protein A affinity column. Unbound proteins were then washed away, and the bound proteins were removed from the column using low pH glycine-HCl buffer. The purified antibody proteins were collected in fractions, OD at 280nm measured, then positive fractions were pooled and dialyzed. The concentration of the purified antibodies was determined, and reactivity tested using an ELISA plate coated with dilute turtle serum. Dilutions of the purified HL673 were detected by anti-mouse IgG-horseradish peroxidase (HRP). Furthermore, some of the antibody preparation was conjugated to biotin. After dialysis, the HL673-biotin was tested by ELISA with dilute turtle serum and detected by streptavidin-HRP. The newly biotinylated antibody was incubated with blood and spleen samples from both adult and hatchling red- eared slider turtles. Bound antibodies were detected using streptavidin-fluorochrome and B cell populations identified using flow cytometry. Our results showed successful detection of turtle B cells using the labeled mAb in both hatchling and adult turtle cell samples. Future studies will use this reagent to investigate the distribution and function of B cells in reptile gut immunity. This work was supported by NSF 1725199 and NIH 1R15AI140118 – 01.
Dredged materials are taken from Illinois waterways by the hundreds of thousands of cubic yards each year. These materials make up a composition that varies by the location of dredging but invariably contain sand and clay brought up from the bottom of rivers and lakes. These materials are amassed at three locations throughout the state. While there is wide speculation for beneficial uses, dredged materials do not currently have any definitive use. We tested the hypothesis that dredged materials could be a useful component of constructed soil by measuring the height of native prairie plants grown in one of five soil mixes in a greenhouse experiment. Plants of four species native to Illinois prairies were grown individually in a soil mix ranging from 0 to twothirds dredged material for 8 weeks. These consisted of three herbaceous dicots and one grass- each having 5 replicates. Height measurements were taken when planted, and three additional times including when harvested. Shoots were harvested, dried and weighed. Soil type significantly affected growth of three of the four species with growth peaking in mixes that included small proportions of dredged material. We conclude that dredged sand and silt can be useful components of soil for the four prairie species studied.
Intracellular transportation is vitally important to cell function: without the help of motor proteins carrying molecular cargo across the vast distances of the cell’s cytosol, few cellular mechanisms would be able to take place. We study the heterodimeric motor protein kinesin-2 (KIF3A/KIF3B), which is of particular interest due to its implication in several human genetic diseases. KIF3A/KIF3B drives cilia formation as well as transport, so it is expressed in many cell types. Trucks consume gas to travel highways. Kinesins need ATP to walk along microtubules, or “cell highways.” The resources of a cell must be allocated economically. To save energy, motors must only run when needed to transport cargo. We aimed to investigate how KIF3A/KIF3B regulates its own movement through a process called “autoinhibition.” Previous kinesin research provides a framework for possible autoinhibition mechanisms. The autoinhibition of many kinesins is mediated through hinges in certain regions that allow the protein to interact with itself, folding back and inhibiting the microtubule-binding motor domains. These interactions are thought to block cargo-kinesin and microtubule-kinesin interactions and thereby inhibit microtubule-based movement and ATP consumption. The specific regions of tail and motor domain that interact in KIF3A/KIF3B to facilitate autoinhibition are, however, not known. We hypothesize that heterodimeric kinesin-2 is also autoinhibited by specific interactions between tail-, stalk-, and motor domains and that by disrupting these interactions the motor will be rendered constitutively active. To test this hypothesis, we generated a fluorescentlytagged, engineered motor in which we fused the motor domain of KIF3A to the stalk and tail domain of KIF3B and vice versa. Fluorescence microscopy revealed that unlike the wild-type motor which was diffusely distributed across the cytosol, this engineered motor strongly accumulated in the cellular periphery. This accumulation is a hallmark phenotype for a kinesin that has lost regulation by autoinhibition. We are moving forward with this project by constructing kinesin-2 constructs that have successively longer truncations of these regions of interest. Analyzing the intracellular localization of these motors will allow us to map the interactions that mediate the autoinhibition of the KIF3A/KIF3B motor.
Duchenne muscular dystrophy (DMD) is a degenerative muscular disorder that affects 1 in 3,500 males and is characterized by progressive muscle weakness, loss of ambulation, and premature death. DMD is caused by an absence of the dystrophin protein. Dystrophin connects the actin cytoskeleton to the extracellular matrix, which stabilizes the sarcolemma during muscle contraction. In addition to the phenotypes of muscle degeneration, loss of ambulation, and premature death, other phenotypes of this disease include elevated calcium levels, oxidative stress, and mitochondrial damage. It is not precisely understood how the loss of dystrophin affects the molecular mechanisms that lead to degeneration. We are investigating gene expression in dystrophic C. elegans that genetically model Duchenne muscular dystrophy through mutations in the worm dystrophin homolog (dys-1). Under high exertion exercise, the dys-1(eg33) strain of dystrophic worms recapitulates the most severe features of DMD. However, a dystrophic strain with a similarly missense mutation near the eg33 loci (dys-1(cx18)), displays a significantly less severe phenotype. RNA seq data from muscle specific tissue identified several genes that have differential expression between these two dystrophic strains. We have identified differentially expressed genes with known roles in calcium handling, muscle contractile ability, and mitochondrial function. We are presently using RNA interference as a screen to identify genes that decrease calcium levels in muscle. Genes that show decreased calcium levels when silenced will then be further studied to see how this manipulation impacts locomotor ability and longevity. This approach has the potential to identify therapeutic targets sensitive to manipulation and help improve the quality of life of individuals suffering with Duchenne muscular dystrophy.
Habitat temperature determines the temperature range in which the nervous system can function Around the world, climate change is causing fluctuations in environmental temperatures. Since all biological processes are temperature-dependent, environmental temperature fluctuations can be detrimental to important behaviors and physiological functions. This is especially true for ectothermic species whose body temperatures change with ambient temperature. In the nervous system, an increase in temperature causes an imbalance of ionic conductances that are key to neural processing and communication, leading to failure of neuronal function. Thus, maintaining nervous system function over physiological temperature ranges is critical for survival. Although the effects of climate change induced environmental temperature changes on behavior and mortality are well studied, the effects on underlying nervous system function are far from clear. To better understand environmental temperature effects on nervous system function, I am investigating temperature responses in a well-characterized motor system in the crustacean stomatogastric nervous system (STNS). The STNS controls rhythmic chewing and filtering in the animal's stomach, serving a vital function in survival. Of its two neuronal circuits, one is intrinsically temperature-compensated, while the other requires extrinsic neuromodulation to function in an extended temperature range. In a comparative approach, I record the rhythms of both neuronal circuits using established electrophysiology methods and identify the range of temperatures at which the rhythms remain stable in several related crab species: Cancer borealis, Cancer magister, and Carcinus maenas. The question driving my research is whether the environmental temperatures experienced by a species affect the temperatures at which the nervous system can function. My results from the intrinsically temperature-compensated neuronal circuit show that the temperatures at which the rhythm is stable correspond to environmental temperatures, both in mean and range of temperatures. The species that experiences a greater mean and range of temperatures in its environment had a rhythm that was stable at a greater mean and range of temperatures. Specifically, C. maenas, which experiences habitat temperatures ranging 0-35°C, had a rhythm that was stable from around 6-34°C while C. borealis and C. magister, which both experience habitat temperatures ranging 3-25°C, had rhythms that remained stable from around 6- 26°C. My data thus suggest that habitat temperature determines the mean and range of temperatures at which the nervous system can function.