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Factors and mechanisms contributing to the regulation of the developmental cycle in Chlamydia trachomatis
No full textChlamydia is an obligate intracellular bacterium causing one of the most commonly reported bacterial sexually transmitted infections in humans. It is asymptomatic in nature and exposure to infants can lead to neonatal blindness. Despite such serious consequences and high stakes, there are restricted treatment options and no available vaccines. Developing therapeutics has been challenging with chlamydia because it has been difficult to manipulate the organism and hence there is a paucity of available information about the basic biology of the organism. This is further complicated by 30% of the chlamydial genome being unannotated and defined as hypothetical protein coding genes.This dissertation attempts to bridge the gap of knowledge about chlamydial biology by using two different methods- 1) Through genetic studies by transposon mutagenesis and inter-species recombination in Chlamydia and 2) Through structure-function studies to characterize the role of 2 hypothetical proteins in Chlamydia trachomatis.The first aspect of the document emphasizes on how different kinds of unbiased genetic approaches can help us delve into the roles of gene products in chlamydial growth and infection capabilities. The genetic studies from transposon mutagenesis in Chlamydia trachomatis demonstrated the role of several chlamydial proteins in the developmental cycle of Chlamydia trachomatis by characterizing select mutants. Mutants obtained in this study can be individually characterized and insights to the regulation and role of different genes during the progression of the developmental cycle can be gathered. The second part of the genetic study concentrated on understanding the species-specific role of genes to understand the pathogenesis. In the context of this dissertation, once the chimeras were obtained around the region of differences between Chlamydia trachomatis and Chlamydia muridarum- called the Plasticity Zone (PZ), the growth phenotypes were assessed. These chimeras had the Chlamydia muridarum plasticity zone in a Chlamydia trachomatis background. Results support that the genes in the PZ region contribute to the growth and inclusion size expansion irrespective of the species but the genes that are directly contributing to these factors are part of the full PZ and the right partial PZ. The chimeras majorly had Chlamydia trachomatis-like growth and further validation of the genes crossed over in these recombinants is warranted.The second and major aspect of this dissertation focuses on understanding gene regulation and the role of hypothetical proteins in gene regulation during the developmental cycle of Chlamydia trachomatis. Here we attempted to characterize two hypothetical proteins- CT398 (CdsZ) and CT457 (YebC). These proteins had little sequence similarity with other bacteria but had no identified role in Chlamydia trachomatis. The protein structures of these proteins were crystalized, and the function was assessed using structural homology and in vivo over-expression of the protein approaches. Our data support that CdsZ over-expression had a profound impact on chlamydial RB to EB reorganization. RNA seq results showed down-regulation of a subset of late genes. Moreover, this regulation of conversion was mediated in a temporal fashion and most likely through the CdsZ interacting with RNA polymerase machinery during transcription. The data also suggests its regulatory role based on interaction with the Type III secretion system and its effect on pathogenesis. Further validation is needed to understand this mechanism. The last chapter focuses on the regulatory role of CT457 (YebC) during the developmental cycle. Although, we have transcriptional and translational data to show that it is constitutively present through the developmental cycle, over-expression had no effect on chlamydial growth or gene expression. Further optimization of assays is needed to decipher the exact role of CT457 given that it is a conserved protein and it could have the same role in different species of Chlamydia
Extension and Replication of DRA without Extinction on Treatment Integrity Errors: A Translational Evaluation
No full textDifferential reinforcement of alternative behavior (DRA) and extinction (EXT) have been used to successfully reduce problem behavior (Athens & Vollmer, 2010; Brown et al., 2020; Kunnavatana et al., 2018). Though effective, there are unwanted side effects of EXT such as resurgence and extinction-induced aggression (Lerman et al., 1999). DRA without EXT is also effective in reducing problem behavior (Athens & Vollmer, 2010); however, it is unclear how well it must be implemented to maintain treatment effects. The current study replicates and extends Glover (2021) by conducting a translational evaluation of treatment integrity errors with DRA without EXT on analogues to problem and alternative behavior. Thus far, results suggest omission errors for alternative behavior and combined errors are most detrimental within DRA without EXT.Keywords: differential reinforcement of alternative behavior, treatment integrity, translational study, problem behavio
Buying the Most Beautiful Woman: A Marxist-Feminist Critique of The Great Gatsby—100 Years Later
No full textThe Great Gatsby is one of the most widely read classic novels, usually presented to readers for the first time in high school. While a plethora of criticism and analysis of the novel exists, this essay presents a new framework through which to read and teach the novel. Most scholars have discussed Fitzgerald’s authorial intention of writing a capitalist critique, yet I examine how the anti-capitalism gets lost in the misogynistic, patriarchal nature of the story. I put the novel, its literature review, and Fitzgerald’s own economic ideology in conversation with each other by tracing his personal writing and development. I suggest that Marxist feminism is a necessary intervention, since it has not been applied yet in a thorough, sophisticated way. Marxist feminism, as a literary framework, uses a Marxist foundation to look at the ways in which capitalism exacerbates the effects of the patriarchy, reducing women to commodities in a capitalist system, being traded, bartered for, and fetishized. Using this definition as the main framework, I closely analyze the relations between women and men in the novel—how their relationships can be viewed as transactional and parallel to the relationship between commodities and capitalists in a Marxist system. By critiquing The Great Gatsby through a Marxist-feminist lens, I argue that Fitzgerald’s novel serves as a poignant depiction of women’s oppression under capitalism, particularly in the 1920s, that remains relevant today. As readers continue to read this novel as required literature, I contend that this new framework can modernize the study of this much-loved classic
Tracking the Time Course of Phonetic Cue Integration in the Perception of Korean Stop Contrasts by Korean and English Listeners
No full textThe present study investigates the time course of acoustic cue integration in the processing of the Korean three-way laryngeal stop contrast by native Korean listeners and English second language (L2) learners of Korean. As such, this study seeks to understand how native listeners and L2 learners weight and integrate fine-grained acoustic information in spoken word recognition. Specifically, this study investigates three important issues in speech perception and spoken word recognition. The first issue is that acoustic information from different cues often arrives asynchronously as the speech signal unfolds, thus raising the question of how asynchronous acoustic cues are integrated over time. A second critical question is whether the cue integration strategy used in the native language (L1) determines the cue integration strategy adopted in the L2. A third important issue is that of individual differences in cue weighting and cue integration strategies and what might be the potential source of such variabilities. From these issues, three research questions arise: (i) Are acoustic cues integrated continuously when the weight of the cue available later is greater than that of the cue available earlier? (ii) Do listeners’ cue weighting and cue integration strategies in the L1 affect how they weight and integrate acoustic cues that signal a similar phonological contrast in the L2? And (iii) does an individual’s cue weighting predict their cue integration strategy, and are both predicted by working memory capacity?This study addresses these questions by determining: (a) how individual native Korean listeners weight and integrate VOT (cue available early in the speech signal) and onset F0 of the following vowel (cue available later) when hearing Korean isolated words that begin with a stop; (b) how individual English L2 learners of Korean weight and integrate the VOT and onset F0 of the following vowel when hearing Korean isolated words that begin with a laryngeal stop; and (c) whether listeners’ cue weighting and cue integration are related to listeners’ working memory capacity.A cue-weighting speech perception experiment measured listeners’ perceptual reliance on acoustic cues to the Korean stop contrast. During the cue-weighting task, participants heard a stimulus that was part of a matrix consisting of seven steps of VOT and seven steps of F0 and identified what they heard from two given alternatives. The results of the cue-weighting task showed that Korean listeners use F0 as the primary cue and VOT as the secondary cue for perceiving the aspirated vs. lenis and the lenis vs. fortis contrasts, but they use VOT as the primary cue for perceiving the aspirated vs. fortis contrast. English L2 learners of Korean were found to transfer their relative cue weighting from their L1 English stop voicing contrast to the processing of the L2 Korean laryngeal stop contrast, relying primarily on VOT to perceive the Korean contrasts. Individual listeners’ perceptual reliance on acoustic information was quantified by their responses to the cue-weighting task, serving as a foundation for predicting the real-time processing of acoustic information, which was measured with an eye-tracking experiment.The visual-world eye-tracking paradigm measured listeners’ timing of VOT integration in the real-time processing of acoustic information in lexical access. In the eye-tracking experiment, listeners saw a display with four printed Korean words: one target, one competitor, and two distractors. Participants’ eye movements were recorded as they heard a target word within the carrier sentence and clicked on the corresponding word. The results showed that, at the group level, Korean listeners’ timing of VOT integration was delayed in the condition with an aspirated target and a lenis competitor and in the condition with a lenis target and a fortis competitor, in which F0 (cue available later in the speech signal) is the primary cue for perceiving the corresponding contrasts. These results suggest that the timing of cue integration is associated with the relative weighting of acoustic cues. English L2 learners of Korean showed that their timing of VOT integration was not delayed except for the condition with a lenis target and a fortis competitor, where they had difficulties identifying target stops. This suggests that their transferred relative cue weighting from the L1 is associated with their real-time processing of acoustic information in the L2.At the individual level, Korean listeners who relied more on F0 showed more delayed timing of VOT integration, further elucidating the relationship between cue weighting and the time course of cue integration. English L2 learners of Korean did not show a significant relationship between the two variables. The effect of working memory was overall not strong, although it predicted the perception of some contrasts.The present results speak to the literature on the mechanisms that underlie the time course of cue integration as the speech signal unfolds and suggest that listeners’ real-time processing of asynchronous acoustic information in lexical activation is modulated by the informativeness of perceptual cues. As such, this study provides a nuanced perspective for a better understanding of listeners’ moment-by-moment process of acoustic information in spoken word recognition
Perceptions of Politicization, Court Knowledge, and Attitudes toward the Supreme Court
No full textWhat impacts people’s attitudes toward the Supreme Court? In recent years, concerns have emerged about the politicization of the Court. High-profile cases, such as Bush v. Gore (2000), and more recently, Dobbs v. Jackson Women’s Health Organization (2022), highlight the ideological division of the Court. Prior research has considered a wide range of variables believed to shape people’s attitudes toward the Court. Among these variables include such elements as the effect of court knowledge and perceived judicial politicization. Evidence suggests that high levels of knowledge about the Court are associated with more positive assessments of the institution. Comparatively, high levels of perceived politicization result in strongly negative attitudes toward the Court.In examining this phenomenon, I argue that the independent effect associated with high levels of court knowledge will result in high levels of court approval and perceived legitimacy. Conversely, the independent effect of high levels of perceived politicization will have a negative effect on both court approval and perceived legitimacy. In addition, I account for the interaction effect of court knowledge on approval and legitimacy at different levels of perceived politicization. My findings support existing research when accounting for the independent effect of court knowledge and perceived politicization. However, in examining the interaction between these two variables, I find that the effect of court knowledge on approval is negative at the highest level of perceived politicization; but, is positive when measuring the effect of court knowledge on legitimacy at the highest level of perceived politicization. These findings, nonetheless, offer a novel contribution in the literature on attitudes toward the Supreme Court
Power Moves: Chinese FDI in Renewable Energy in Brazil’s Northeast
No full textSince the initiation of a strategic economic partnership in 1993, business entities from the People’s Republic of China have invested into many of the major sectors of the Brazilian economy. The Brazilian industry sectors attracting the most Chinese foreign direct investment (FDI) have shifted throughout the past thirty years following patterns based on internal pressures and government priorities. The current cycle began in 2015, when the focus of Chinese investment shifted to energy production and transmission, with a more recent emphasis on renewable energy projects. Chinese investments tracked since 2007 have focused on the southeastern Brazilian states, but in 2019 the northeastern states attracted the highest number of new projects. These recent investments were primarily directed to energy projects located in or providing services to the state of Bahia. This investigation reviews the history of the Sino-Brazilian economic relationship, especially with respect to Chinese FDI directed to Brazil and, most recently, the energy sector, in particular. The investigation then identifies factors that made Bahia attractive for China’s investments, potential strategies to attract further investment, and lessons from Bahia’s experience for the other states of the northeastern region seeking Chinese FDI
Native Microbes Amplify Native Seedling Establishment and Diversity While Inhibiting a Non-Native Grass
Get PDFAlthough several studies have shown increased native plant establishment with native microbe soil amendments, few studies have investigated how microbes can alter seedling recruitment and establishment in the presence of a non-native competitor. In this study, the effect of microbial communities on seedling biomass and diversity was assessed by seeding pots with both native prairie seeds and a non-native grass that commonly invades US grassland restorations, Setaria faberi. Soil in the pots was inoculated with whole soil collections from ex-arable land, late successional arbuscular mycorrhizal (AM) fungi isolated from a nearby tallgrass prairie, with both prairie AM fungi and ex-arable whole soil, or with a sterile soil (control). We hypothesized (1) late successional plants would benefit from native AM fungi, (2) that non-native plants would outcompete native plants in ex-arable soils, and (3) early successional plants would be unresponsive to microbes. Overall, native plant abundance, late successional plant abundance, and total diversity were greatest in the native AM fungi+ ex-arable soil treatment. These increases led to decreased abundance of the non-native grass S. faberi. These results highlight the importance of late successional native microbes on native seed establishment and demonstrate that microbes can be harnessed to improve both plant community diversity and resistance to invasion during the nascent stages of restoration
Associations between Alcohol-Free Sources of Reinforcement and the Frequency of Alcohol and Cannabis Co-Use among College Freshmen
Get PDFCo-use of alcohol and cannabis is common among young adults in the United States. A behavioral economics framework indicates that greater engagement in substance-free sources of reinforcement may be protective against co-use frequency. The current study tested the association between proportionate alcohol-free reinforcement and the frequency of co-use among college freshmen. Participants (N = 86) were freshmen who enrolled in a freshman orientation course and completed surveys at the beginning of the semester. Past month alcohol use, cannabis use, and reinforcement from alcohol-free and alcohol-involved activities were assessed. A zero-inflated Poisson regression was used to test the association between proportionate alcohol-free reinforcement and days of co-use. The results indicated that proportionate alcohol-free reinforcement was negatively associated with co-use days in the count model when controlling for alcohol use days and gender as covariates (β: −3.28, p = 0.016). Proportionate alcohol-free reinforcement did not significantly differentiate individuals who did not engage in co-use in the zero-inflated model (β: −1.68, p = 0.497). The study suggested that greater proportionate alcohol-free reinforcement may be associated with lower engagement in the co-use of alcohol and cannabis among young adults. Increasing engagement in alcohol-free sources of reinforcement may be considered a target for co-use prevention or harm reduction efforts
Early Release Science of the exoplanet WASP-39b with JWST NIRSpec G395H
Get PDFMeasuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems1,2. Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based3,4,5 and high-resolution ground-based6,7,8 facilities. Here we report the medium-resolution (R ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref. 9), obtained with the Near Infrared Spectrograph (NIRSpec) G395H grating of JWST. Our observations achieve 1.46 times photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO2 (28.5σ) and H2O (21.5σ), and identify SO2 as the source of absorption at 4.1 μm (4.8σ). Best-fit atmospheric models range between 3 and 10 times solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO2, underscore the importance of characterizing the chemistry in exoplanet atmospheres and showcase NIRSpec G395H as an excellent mode for time-series observations over this critical wavelength rang
Localization of Multiple Jellyfish Toxins Shows Specificity for Functionally Distinct Polyps and Nematocyst Types in a Colonial Hydrozoan
Get PDFHydractinia symbiolongicarpus is a colonial hydrozoan that displays a division of labor through morphologically distinct and functionally specialized polyp types. As with all cnidarians, their venoms are housed in nematocysts, which are scattered across an individual. Here, we investigate the spatial distribution of a specific protein family, jellyfish toxins, in which multiple paralogs are differentially expressed across the functionally specialized polyps. Jellyfish toxins (JFTs) are known pore-forming toxins in the venoms of medically relevant species such as box jellyfish (class Cubozoa), but their role in other medusozoan venoms is less clear. Utilizing a publicly available single-cell dataset, we confirmed that four distinct H. symbiolongicarpus JFT paralogs are expressed in nematocyst-associated clusters, supporting these as true venom components in H. symbiolongicarpus. In situ hybridization and immunohistochemistry were used to localize the expression of these JFTs across the colony. These expression patterns, in conjunction with known nematocyst type distributions, suggest that two of these JFTs, HsymJFT1c-I and HsymJFT1c-II, are localized to specific types of nematocysts. We further interpret JFT expression patterns in the context of known regions of nematogenesis and differential rates of nematocyst turnover. Overall, we show that JFT expression patterns in H. symbiolongicarpus are consistent with the subfunctionalization of JFT paralogs across a partitioned venom system within the colony, such that each JFT is expressed within a specific set of functionally distinct polyp types and, in some cases, specific nematocyst types