HHMI Life Science Freshman Research Scholars
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Item Effects of L protein on MreB and cell lysis(Oklahoma State University, 2018-04-19) Templon, Alannah; Karthik, Reddy; Young, RyThe MS2 bacteriophage is a single-stranded, positive-strand RNA virus that contains four genes: mat, coat, rep, and L. The L protein is responsible for cell lysis, although relatively little is known about its mode of action. Unlike other viral lysis proteins, which inhibit cell wall synthesis at the division site causing midcell blebs, L protein appears to cause lysis at random cellular locations, as seen by bleb formation throughout the cell. We hypothesized that L protein works with MreB, an essential protein for cell wall synthesis, which is localized throughout the cell body. We seek to identify how L protein affects MreB by possibly: causing the mislocalization of MreB at specific sites of lysis, activating a section of MreB to form a hotspot for cell wall synthesis, or deactivating a section of the MreB pool, causing cell defects. To begin to determine which mechanism is correct, we will measure the localization of MreB in cells undergoing lysis to see if there is a correlation between MreB localization and L protein induced lysis. We will then examine if there is a direct interaction between L protein and MreB using biomolecular fluorescent complementation. Learning how L protein lyses cells will provide us with a better understanding of single gene lysis, which can be applied to phage therapy to kill disease causing bacteria and to effectively prevent bacteriophages from killing helpful bacteria that assist in preventing disease or are important for industrial purposes.Item Phylogeny of Sonoran Desert milkweeds resolved with plastid genome sequences(Oklahoma State University, 2019-04-27) Gentry, ShelbyThe Sonoran Desert Clade milkweeds have very unusual traits, including species that are nearly leafless and shrubby. This clade includes 9 species for which we estimate a phylogenetic tree and use this information to better understand why species within this clade are diverging from their ancestral species. To do this we use plastid genomes to find genetic differences among the species. We assembled and aligned plastomes for multiple individuals of each species and found the maximum likelihood phylogenic tree. From the results we found that the Sonoran Desert Clade forms one clade rather than multiple. We found interesting relations between some of the species within the Sonoran Desert Clade. There was hybridization that we found within the results. This will help us further our study on the evolution of the Asclepias species.Item Effects of paternal deprivation on nestling zebra finches (Taeniopygia guttata)(Oklahoma State University, 2019-04-27) Giddens, EmilyEarly interactions between parents and offspring have been shown to influence behavior development in avian offspring, which links to their fitness as adults. In bi-parental species, previous research has looked at what developmental alterations have occurred when the mother is removed from the nest during the developmental stage. By looking at the behaviors of the offspring when the father is removed during the nestling stage, we can better understand where the developmental alterations are stemming from. In this study, zebra finches were assigned to control and paternal removal groups, and from post-hatch day 1 through 18, we quantified important parent-offspring interactions that occurred during 1-hour long video recordings inside nests. We are still in the process of quantifying behaviors from all 19 nests, but we expect that the mother will attempt to compensate for the lack of paternal care in the paternal removal group, but not be fully successful. As a result, offspring will have fewer interactions with a parent in the paternal removal group. Determining the effects of paternal deprivation during the nestling stage will allow us to further understand the importance of bi-parental care during development.Item Dying light: Detecting tree mortality risk with chlorophyll fluorescence(Oklahoma State University, 2019-04-27) Giddens, MeganIncreased greenhouse emissions have altered Earth's climate, resulting in rapid climate change which has brought warm droughts-especially in semi-arid regions-leading to forest die-off and dieback. Physiological stresses associated with climate change pose a great risk to tree survival, as future climate changes are likely to increase the intensity of drought. Some of these effects can be observed in species such as pinon pine (Pinus edulis), which typically have a high drought tolerance but have succumbed to widespread drought-induced mortality in recent decades, likely due to hydraulic failure. Currently, remotely sensing hydraulic failure is not possible. However, our results suggest chlorophyll fluorescence in dark-adapted samples is an indicator of water stress and the variation of chlorophyll fluorescence within a tree increases as drought stress prolongs. With continued observation, we believe chlorophyll fluorescence will show to be a useful proxy for hydraulic failure to aid mortality predictions as well as predict how future climate changes will impact terrestrial vegetation and climate feedback loops.Item Examining the role of MekA and YakA in Dictyostelium signaling(Oklahoma State University, 2019-04-27) Dreadfulwater, StormieA series of trials were conducted to determine how each protein or kinase plays a role in the signaling of a cell. Among the factors tested were response time, extent of response, and the response under varying stimuli (stimuli included cAMP and folic acid). The primary focus of my individual tests was the role of the kinases mekA and yakA, and I collaborated with my partner to study PakF. Throughout these tests it was shown that yakA- cells respond to either stimuli similar to wild-type cells but mekA- cells show a slower response or no response at all. With these results in mind, MekA was shown to play a possible role in the adaptation of the response, bringing a cell back to its unstimulated state. It is unclear what role YakA plays within a cell, but it does not seem to play a role in this signaling process.