MICROBIAL DIVERSITY THROUGH SPACE AND TIME: DISPERSAL AND DORMANCY IN MICROBIAL COMMUNITIES

Thesis (Ph.D.) - Indiana University, Biology/University Graduate School, 2020Microorganisms are the most diverse organisms on the planet. Understanding the processes by which they are assembled into communities across space and time is a primary goal of microbial ecology. I employed empirical and simulation studies to investigate the effects of dispersal and dormancy on patterns of microbial biodiversity. Microorganisms are thought to have high rates of dispersal, linking communities across space to form a metacommunity. In Chapter 1, I investigated the importance of local- versus regional-scale processes for the assembly of planktonic and sediment-associated bacterial communities in a stream network. Using phylogenetic and taxonomic null models, I found habitat-specific spatial patterns of community assembly in the network, demonstrating the potentially overlooked importance of vertical habitat structure for microbial diversity in stream metacommunities. In Chapter 2, I investigated the roles of biotic interactions and dormancy for the maintenance of microbial biodiversity in University Lake, Indiana, USA. By comparing metabolically active and total diversity in a high-resolution time series, I found evidence that stabilizing biotic interactions allow taxa to persist at the local scale, aided by a dormant seed bank. In Chapter 3, I synthesized the roles of dispersal and dormancy in metacommunity ecology by analyzing empirical data and simulation models. In Chapter 4, I tested predictions about the effects of dormancy and dispersal in University Lake. Dispersal from the neighboring terrestrial ecosystem influenced diversity near the terrestrialaquatic interface. However, most terrestrial-derived bacteria were apparently dormant, with only a few taxa reaching high abundances in the metabolically active portion of the aquatic community. Taken together, this dissertation provides empirical demonstrations of how dispersal and dormancy affect microbial communities in nature. More broadly, it develops novel insights into the roles of dispersal and dormancy in metacommunities

An Aesthetics of Everything Else: Flat Ontologies and the Everyday

This thesis considers everyday experience as the defining condition of craft that has largely escaped scholarly attention. Critically responding to craft’s theoretical stance as the ‘other’ of art and industry, I turn to philosophy to examine how non-Kantian strands of aesthetic theory might enable art historical study of craft to encompass the experience of ordinary making. Through an examination of flat ontological frameworks put forth by New Materialism and its older iterations in John Dewey and Indigenous thought, I argue that aesthetic frameworks deriving from flat ontologies, or what I call “flat aesthetics,” provide a way to return to a less fragmented creative landscape in which craft is the ground for all creative practice. Drawing inspiration from art historical examinations of the counterculture and neo-avant garde movement Fluxus, I focus on how flat ontologies provide the philosophical basis for an everyday aesthetics that recognizes the ordinary experience of making in relational terms, as part of a dynamic network of agential forces. I conclude by speculating that understanding everyday craft in this way holds potential to renew its relevance and pertinence to the ethical pursuit of “the good life,” pointing to new directions for further work to be done in this area

Contesting Husbands and Masters: Law, Society, and the Marital Household in Colonial Lima

University of Minnesota Ph.D. dissertation. July 2015. Major: History. Advisor: Sarah Chambers. 1 computer file (PDF); vii, 183 pages.This dissertation examines marital relations, and specifically marital conflicts, in early colonial Lima in order to analyze gender and power in the Spanish Empire. Through my reading of cases held before the ecclesiastical tribunal, I show how wives and their supporters resisted and questioned husbands’ authority primarily through reifying of patriarchal norms, in the form of the ideals of manhood. Rather than challenges based on the perceived rights of women, the citing of failures of marital masculinity dominated the discourse of these trials. This marital masculinity encompassed the nature, characteristics, and actions expected of a married man. This manhood was rooted in broader early modern Catholic ideals and comprised expectations of provision, protection, and fidelity. In addition to following Church prescriptions on appropriate behavior for men, the patriarchal expectations found in these cases involved upholding the racial hierarchy of colonial society. Wives and witnesses highlighted instances such as the use of racial epithets and infidelity that crossed racial lines as further failures to live up to the masculine ideal. This dissertation approaches the dynamics of gender domination from a number of perspectives. In chapter 1, I examine the petitions by women seeking a divorcio (ecclesiastical divorce which dictated the separation of bed and board) and analyze how they criticize their husbands for falling to fulfill their marital masculinity. Chapter 2 shows how mothers and brothers intervened in marital conflicts and reveals their investment in gendered authority. Looking beyond parents and siblings, chapter 3 highlights how community members, and especially neighbors and enslaved Africans, helped to police the duties of husbands through their testimonies to the court. Chapter 4 analyzes the conflicts between married slaves and their masters over relocation that would separate the couple to further demonstrate the link between race and manhood, one in which white masculinity trumped black masculinity. Throughout these trials, arguments based on marital masculinity proved to limit the power of patriarchs, namely husbands, but, as I demonstrate, did little to mitigate the extent of gender domination ingrained in the patriarchal structures of Lima and the broader Spanish Empire, as the patriarchal authority shifted from husbands to Church officials.Wisnoski III, Alexander. (2015). Contesting Husbands and Masters: Law, Society, and the Marital Household in Colonial Lima. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/191361

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Circadian Modulation of Neurons and Astrocytes Controls Synaptic Plasticity in Hippocampal Area CA1

Most animal species operate according to a 24-h period set by the suprachiasmatic nucleus (SCN) of the hypothalamus. The rhythmic activity of the SCN modulates hippocampal-dependent memory, but the molecular and cellular mechanisms that account for this effect remain largely unknown. Here, we identify cell-type-specific structural and functional changes that occur with circadian rhythmicity in neurons and astrocytes in hippocampal area CA1. Pyramidal neurons change the surface expression of NMDA receptors. Astrocytes change their proximity to synapses. Together, these phenomena alter glutamate clearance, receptor activation, and integration of temporally clustered excitatory synaptic inputs, ultimately shaping hippocampal-dependent learning in vivo. We identify corticosterone as a key contributor to changes in synaptic strength. These findings highlight important mechanisms through which neurons and astrocytes modify the molecular composition and structure of the synaptic environment, contribute to the local storage of information in the hippocampus, and alter the temporal dynamics of cognitive processing

Toward a Generalizable Framework of Disturbance Ecology Through Crowdsourced Science

© 2021 Graham, Averill, Bond-Lamberty, Knelman, Krause, Peralta, Shade, Smith, Cheng, Fanin, Freund, Garcia, Gibbons, Van Goethem, Guebila, Kemppinen, Nowicki, Pausas, Reed, Rocca, Sengupta, Sihi, Simonin, Słowiński, Spawn, Sutherland, Tonkin, Wisnoski, Zipper and Contributor Consortium.Disturbances fundamentally alter ecosystem functions, yet predicting their impacts remains a key scientific challenge. While the study of disturbances is ubiquitous across many ecological disciplines, there is no agreed-upon, cross-disciplinary foundation for discussing or quantifying the complexity of disturbances, and no consistent terminology or methodologies exist. This inconsistency presents an increasingly urgent challenge due to accelerating global change and the threat of interacting disturbances that can destabilize ecosystem responses. By harvesting the expertise of an interdisciplinary cohort of contributors spanning 42 institutions across 15 countries, we identified an essential limitation in disturbance ecology: the word ‘disturbance’ is used interchangeably to refer to both the events that cause, and the consequences of, ecological change, despite fundamental distinctions between the two meanings. In response, we developed a generalizable framework of ecosystem disturbances, providing a well-defined lexicon for understanding disturbances across perspectives and scales. The framework results from ideas that resonate across multiple scientific disciplines and provides a baseline standard to compare disturbances across fields. This framework can be supplemented by discipline-specific variables to provide maximum benefit to both inter- and intra-disciplinary research. To support future syntheses and meta-analyses of disturbance research, we also encourage researchers to be explicit in how they define disturbance drivers and impacts, and we recommend minimum reporting standards that are applicable regardless of scale. Finally, we discuss the primary factors we considered when developing a baseline framework and propose four future directions to advance our interdisciplinary understanding of disturbances and their social-ecological impacts: integrating across ecological scales, understanding disturbance interactions, establishing baselines and trajectories, and developing process-based models and ecological forecasting initiatives. Our experience through this process motivates us to encourage the wider scientific community to continue to explore new approaches for leveraging Open Science principles in generating creative and multidisciplinary ideas.This research was supported by the U.S. Department of Energy (DOE), Office of Biological and Environmental Research (BER), as part of Subsurface Biogeochemical Research Program’s Scientific Focus Area (SFA) at the Pacific Northwest National Laboratory (PNNL). PNNL is operated for DOE by Battelle under contract DE-AC06-76RLO 1830

Astragalus Polysaccharides Attenuate Postburn Sepsis via Inhibiting Negative Immunoregulation of CD4+CD25high T Cells

BACKGROUND: Astragalus polysaccharides (APS) isolated from one of the Chinese herbs, Astragalus mongholicus, are known to have a variety of immunomodulatory activities. However, it is not yet clear whether APS can exert an effect on the immune functions of regulatory T cells (Tregs). This study was carried out to investigate the effect of APS on the immune function of peripheral blood Tregs in postburn sepsis. METHODOLOGY/PRINCIPAL FINDINGS: BALB/C mice were randomly divided into six groups as follows: sham burn group, burn control (burn without infection animals) group, burn plus P. aeruginosa group, burn plus P. aeruginosa with APS (50 mg/kg) treatment group, burn plus P. aeruginosa with APS (100 mg/kg) treatment group, and burn plus P. aeruginosa with APS (200 mg/kg) treatment group, and they were sacrificed on postburn day 1, 3, 5, and 7, respectively, with seven animals at each time point. Magnetic microbeads were used to isolate peripheral blood Tregs and CD4(+) T cells. Phenotypes were analyzed by flow cytometry, and cytokine levels were determined with ELISA. In the burn plus P. aeruginosa group, forkhead/winged helix transcription factor p3 (Foxp3) expression on CD4(+)CD25(+)Tregs were strongly enhanced in comparison to the sham group, and the capacity of CD4(+)CD25(+)Tregs to produce interleukin (IL)-10 was markedly increased. Administration of APS to inhibit CD4(+)CD25(+)Tregs could significantly decrease expression of Foxp3 on CD4(+)CD25(+)Tregs, and IL-10 production in burned mice with P. aeruginosa infection. At the same time, proliferative activity and expression of IL-2 and IL-2Rα on CD4(+) T cells were restored. In contrast, anti-Toll-like receptor 4 (TLR4) antibody could block the effect of APS on Tregs immune function. CONCLUSION: APS might suppress CD4(+)CD25(+)Treg activity, at least in part, via binding TLR4 on Tregs and trigger a shift of Th2 to Th1 with activation of CD4(+) T cells in burned mice with P. aeruginosa infection

Precursor lesions of early onset pancreatic cancer

Early onset pancreatic cancer (EOPC) constitutes less than 5% of all newly diagnosed cases of pancreatic cancer (PC). Although histopathological characteristics of EOPC have been described, no detailed reports on precursor lesions of EOPC are available. In the present study, we aimed to describe histopathological picture of extratumoral parenchyma in 23 cases of EOPCs (definition based on the threshold value of 45 years of age) with particular emphasis on two types of precursor lesions of PC: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs). The types, grades, and densities of precursor lesions of PC were compared in patients with EOPCs, in young patients with neuroendocrine neoplasms (NENs), and in older (at the age of 46 or more) patients with PC. PanINs were found in 95.6% of cases of EOPCs. PanINs-3 were found in 39.1% of EOPC cases. Densities of all PanIN grades in EOPC cases were larger than in young patients with NENs. Density of PanINs-1A in EOPC cases was larger than in older patients with PC, but densities of PanINs of other grades were comparable. IPMN was found only in a single patient with EOPC but in 20% of older patients with PC. PanINs are the most prevalent precursor lesions of EOPC. IPMNs are rarely precursor lesions of EOPC. Relatively high density of low-grade PanINs-1 in extratumoral parenchyma of patients with EOPC may result from unknown multifocal genetic alterations in pancreatic tissue in patients with EOPCs