116 research outputs found
Invasive lespedeza cuneata and its relationship to soil microbes and plant-soil feedback
Globalization has lead to increased frequencies of exotic plant invasions, which can reduce biodiversity and lead to extinction of native species. Physical traits that increase competitive ability and reproductive output encourage the invasiveness of exotic plants. Interactions with the soil microbial community can also increase invasiveness through plant-soil feedback, which occurs through shifts in the abundance of beneficial and deleterious organisms in soil that influence the growth of conspecific and heterospecific progeny.
Lespedeza cuneata is an Asian legume that has become a problematic invader in grasslands throughout the United States. While L. cuneata has numerous traits that facilitate its success, it may also benefit from interactions with soil microbes. Previous studies have shown that L. cuneata can alter bacterial and fungal community composition, benefit more from preferential nitrogen-fixing symbionts than its native congener, L. virginica, and disrupt beneficial fungal communities associated with the native grass Panicum virgatum. L. cuneata litter and root exudates also have high condensed tannin contents, which may make them difficult to decompose and allow them to uniquely influence microbial communities in ways that benefit conspecific but not heterospecific plants. Plant-mediated shifts in the relative abundance of beneficial and deleterious microbes that influence future plant growth are known as plant-soil feedbacks.
The objective of this dissertation is to examine plant-soil feedback in the L. cuneata system. In Chapter 2, I conduct a greenhouse experiment that identifies plant-soil feedbacks between L. cuneata and native potential competitors and use whole-community DNA sequencing to identify potential microbial drivers of observed feedbacks. Results showed that L. cuneata limits the growth of itself and native plants, but it benefits from microbes that were enriched in native-conditioned soil. This negative plant-soil feedback may facilitate early stages of L. cuneata invasion. In Chapter 3, I conduct a greenhouse experiment that examines the role that multiple plant chemical inputs may play in facilitating plant-soil feedback. Results suggest that in situ plant-soil feedback is mediated by complex sums of multiple plant inputs, but that root exudates may be especially important for structuring symbiont and pathogen populations. Metabolites from L. cuneata chemical inputs may also directly harm native plant growth. In Chapter 4, I conduct a follow up study to determine whether observations from my greenhouse study are applicable in the field. I found that L. cuneata invasion has lasting affects on soil microbial community composition in the field, which may be sufficient to drive plant-soil feedback in situ. Similar symbiont and decomposer OTUs were identified as being enriched by L. cuneata in both the greenhouse and the field.
The results from this dissertation provide a novel examination of the influence of L. cuneata on plant-soil feedback patterns. As plant-soil feedbacks influence the outcome of plant competitive dynamics, they may have large implications for effects of exotic plants on invaded ecosystems
Metabolic reprogramming through fatty acid transport protein 1 (FATP1) regulates macrophage inflammatory potential and adipose inflammation
OBJECTIVE: A novel approach to regulate obesity-associated adipose inflammation may be through metabolic reprogramming of macrophages (MΦs). Broadly speaking, MΦs dependent on glucose are pro-inflammatory, classically activated MΦs (CAM), which contribute to adipose inflammation and insulin resistance. In contrast, MΦs that primarily metabolize fatty acids are alternatively activated MΦs (AAM) and maintain tissue insulin sensitivity. In actuality, there is much flexibility and overlap in the CAM-AAM spectrum in vivo dependent upon various stimuli in the microenvironment. We hypothesized that specific lipid trafficking proteins, e.g. fatty acid transport protein 1 (FATP1), would direct MΦ fatty acid transport and metabolism to limit inflammation and contribute to the maintenance of adipose tissue homeostasis.
METHODS: Bone marrow derived MΦs (BMDMs) from Fatp1 (-/-) and Fatp1 (+/+) mice were used to investigate FATP1-dependent substrate metabolism, bioenergetics, metabolomics, and inflammatory responses. We also generated C57BL/6J chimeric mice by bone marrow transplant specifically lacking hematopoetic FATP1 (Fatp1 (B-/-)) and controls Fatp1 (B+/+). Mice were challenged by high fat diet (HFD) or low fat diet (LFD) and analyses including MRI, glucose and insulin tolerance tests, flow cytometric, histologic, and protein quantification assays were conducted. Finally, an FATP1-overexpressing RAW 264.7 MΦ cell line (FATP1-OE) and empty vector control (FATP1-EV) were developed as a gain of function model to test effects on substrate metabolism, bioenergetics, metabolomics, and inflammatory responses.
RESULTS: Fatp1 is downregulated with pro-inflammatory stimulation of MΦs. Fatp1 (-/-) BMDMs and FATP1-OE RAW 264.7 MΦs demonstrated that FATP1 reciprocally controled metabolic flexibility, i.e. lipid and glucose metabolism, which was associated with inflammatory response. Supporting our previous work demonstrating the positive relationship between glucose metabolism and inflammation, loss of FATP1 enhanced glucose metabolism and exaggerated the pro-inflammatory CAM phenotype. Fatp1 (B-/-) chimeras fed a HFD gained more epididymal white adipose mass, which was inflamed and oxidatively stressed, compared to HFD-fed Fatp1 (B+/+) controls. Adipose tissue macrophages displayed a CAM-like phenotype in the absence of Fatp1. Conversely, functional overexpression of FATP1 decreased many aspects of glucose metabolism and diminished CAM-stimulated inflammation in vitro. FATP1 displayed acyl-CoA synthetase activity for long chain fatty acids in MΦs and modulated lipid mediator metabolism in MΦs.
CONCLUSION: Our findings provide evidence that FATP1 is a novel regulator of MΦ activation through control of substrate metabolism. Absence of FATP1 exacerbated pro-inflammatory activation in vitro and increased local and systemic components of the metabolic syndrome in HFD-fed Fatp1 (B-/-) mice. In contrast, gain of FATP1 activity in MΦs suggested that Fatp1-mediated activation of fatty acids, substrate switch to glucose, oxidative stress, and lipid mediator synthesis are potential mechanisms. We demonstrate for the first time that FATP1 provides a unique mechanism by which the inflammatory tone of adipose and systemic metabolism may be regulated
Documenting ---- in Bloomington-Normal: A Community Report on Intolerance, Segregation, Accessibility, Inclusion, and Progress, and Improvement
For the local chapter of Not In Our Town, we document intolerance, discrimination, segregation, disparities of access, and disparities in the criminal justice system in Bloomington-Normal, IL. Using archival material, secondary data, and primary data, we examine these issues from the mid-1990s to the present. We also assess the position of the organization in the community and provide strategies for future success. In sum, Bloomington-Normal was and is intolerant; discrimination did and does take place in this community; there are disparities of access and in the criminal justice system; we are segregated. The community is also less of these things than it used to be and is less of these things than other places. Fifteen undergraduate students in Sociology 300, twelve graduate students in Sociology 477, a teaching assistant, and an instructor conducted this study in spring 2017
A communal catalogue reveals Earth's multiscale microbial diversity
Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe
A communal catalogue reveals Earth’s multiscale microbial diversity
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity
The ABC130 barrel module prototyping programme for the ATLAS strip tracker
For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector,
consisting of silicon pixel, silicon strip and transition radiation
sub-detectors, will be replaced with an all new 100 % silicon tracker, composed
of a pixel tracker at inner radii and a strip tracker at outer radii. The
future ATLAS strip tracker will include 11,000 silicon sensor modules in the
central region (barrel) and 7,000 modules in the forward region (end-caps),
which are foreseen to be constructed over a period of 3.5 years. The
construction of each module consists of a series of assembly and quality
control steps, which were engineered to be identical for all production sites.
In order to develop the tooling and procedures for assembly and testing of
these modules, two series of major prototyping programs were conducted: an
early program using readout chips designed using a 250 nm fabrication process
(ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm
processing (ABC130 and HCC130 chips). This second generation of readout chips
was used for an extensive prototyping program that produced around 100
barrel-type modules and contributed significantly to the development of the
final module layout. This paper gives an overview of the components used in
ABC130 barrel modules, their assembly procedure and findings resulting from
their tests.Comment: 82 pages, 66 figure
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
- …