Elevated Temperatures and Drought Favor Invasive Grasses over Native Species

Projected global-scale anthropogenic alterations to native ecosystems include intense and prolonged droughts, increases in atmospheric temperatures, and invasion by non-native species. Understanding how native and non-native grasses tolerate drought and elevated temperatures is essential for projecting native species competitive success. We assessed the effects of elevated temperature and drought on the performance of different growth stages (seed, seedling, and mature plant) of invasive grasses, relative to native species. Further, we determined responses of warm- and cool-season functional groups. The invasive warm�season cespitose grass, Bothriochloa ischaemum) was paired with functionally similar native Schizachyrium scoparium. The invasive cool-season grass, Bromus inermis, was paired with functionally similar native Pascopyrum smithii. We assessed each growth stage at ambient [warm-season (24� C); cool-season (17� C)] and elevated [warm-season (29� C); cool-season (22� C)] temperatures. Seeds were maintained under three water-availability treatments (100%; 83.5%; or 65% field capacity). Seedlings of each species were maintained under for 14 weeks at well-watered (100% field capacity) and extreme drought (65% field capacity). Mature individuals of each species were maintained for 14 weeks at well-watered (100% field capacity) and extreme drought (65% field capacity), as well as two intermediate soil moisture levels (85% and 75% field capacity). Generally, invasive species from each functional group surpassed the corresponding native in germination, biomass production, and re-growth at all climatic conditions. Because associations with AM and saprophytic fungi may aid in host water acquisition and thermal tolerance, we hypothesized these fungal groups would be relatively more abundant when plants were exposed to adverse conditions. However, few differences were apparent between soil microbial communities (i.e. total microbial biomass, or relative abundance of AM or saprophytic fungi) of either native or invasive grass species in response to adverse environmental conditions. Our results indicate invasive perennial grasses are competitively superior to functionally similar native species at all life stages, under ambient and extreme temperature and drought. As more intense and frequent droughts, coupled with elevated temperatures, are projected for grasslands worldwide, our data suggest invasive grasses will out-compete native species at potentially greater magnitudes than currently observed.Natural Resources and Ecology Managemen

A study of selected characteristics of the Kansas rural high school from 1956 to 1961

Call number: LD2668 .R4 1963 D85

Ecological and evolutionary insights into Asclepias: From soil symbionts to disturbances

Milkweeds (Asclepias) are a diverse genus of plants in the family Apocynaceae, with an estimated 130 species found in North America. Milkweed research has increased dramatically over the past two decades, due in part to its importance as the primary food source of monarch (Danaus plexippus) larvae. Reductions in milkweed availability in grasslands of central North America are contributing to D. plexippus population declines. While research assessing the biology of milkweeds has gained recent attention, the interactions of milkweeds, associated soil symbionts, and ecosystem disturbances on milkweed abundance remain unknown. I conducted two interrelated studies to assess the role of phylogenetic relatedness in plant-soil-microbial interactions of various milkweed species, and two additional studies assess the effects of disturbances on individual plants and on long-term abundances in tallgrass prairies. My data highlight the role of phylogenetic distance in influencing PSFs between sympatric congeners. Relative mycorrhizal responsiveness (rMR) of selected milkweeds varied greatly between species, ranging from 27 to 97%. While there was remarkable variation in the degree of responsiveness within the genus, twenty-four of thirty-five species produced significantly greater (p </= 0.05) biomass following inoculation with arbuscular mycorrhizal (AM) fungi, compared to soil without AM fungi. Results also suggest that, due to longer shared evolutionary histories, it is likely that closely related species share a greater overlap of mutualist partners, compared to species with earlier divergence. My research also found productivity, plant defenses, and floral resources of tallgrass prairie forbs that are important for pollinating insects can be significantly reduced by drought, although responses to drought were species-specific. However, abundances of AM fungi associated with milkweeds were relatively unaffected by drought. My research shows long-term abundances of Asclepias viridis, the most abundant milkweed species in the region, are reduced by fire, grazing, and woody cover, while less common species were relatively unaffected. Generally, milkweeds are unaffected by drought at various temporal scales. Milkweeds are an important component of native plant communities, feeding not only monarch larvae, but also providing nectar for countless pollinator species. My research is a testament to the unseen interconnectedness within ecosystems, from soil symbionts to disturbances

Epithelial Cell Coculture Models for Studying Infectious Diseases: Benefits and Limitations

Countless in vitro cell culture models based on the use of epithelial cell types of single lineages have been characterized and have provided insight into the mechanisms of infection for various microbial pathogens. Diverse culture models based on disease-relevant mucosal epithelial cell types derived from gastrointestinal, genitourinary, and pulmonary organ systems have delineated many key host-pathogen interactions that underlie viral, parasitic, and bacterial disease pathogenesis. An alternative to single lineage epithelial cell monoculture, which offers more flexibility and can overcome some of the limitations of epithelial cell culture models based on only single cell types, is coculture of epithelial cells with other host cell types. Various coculture models have been described, which incorporate epithelial cell types in culture combination with a wide range of other cell types including neutrophils, eosinophils, monocytes, and lymphocytes. This paper will summarize current models of epithelial cell coculture and will discuss the benefits and limitations of epithelial cell coculture for studying host-pathogen dynamics in infectious diseases

Physical extraction and fast protein liquid chromatography for purifying flagella filament from uropathogenic Escherichia coli for immune assay

Flagella are expressed on the surface of a wide range of bacteria, conferring motility and contributing to virulence and innate immune stimulation. Host-pathogen interaction studies of the roles of flagella in infection, including due to uropathogenic Escherichia coli (UPEC), have used various methods to purify and examine the biology of the major flagella subunit protein, FliC. These studies have offered insight into the ways in which flagella proteins interact with host cells. However, previous methods used to extract and purify FliC, such as mechanical shearing, ultracentrifugation, heterologous expression in laboratory E. coli strains, and precipitation-inducing chemical treatments have various limitations; as a result, there are few observations based on highly purified, non-denatured FliC in the literature. This is especially relevant to host-pathogen interaction studies such as immune assays that are designed to parallel, as closely as possible, naturally-occurring interactions between host cells and flagella. In this study, we sought to establish a new, carefully optimized method to extract and purify non-denatured, native FliC from the reference UPEC strain CFT073 to be suitable for immune assays. To achieve purification of FliC to homogeneity, we used a mutant CFT073 strain containing deletions in four major chaperone-usher fimbriae operons (type 1, F1C and two P fimbrial gene clusters; CFT073Δ4). A sequential flagella extraction method based on mechanical shearing, ultracentrifugation, size exclusion chromatography, protein concentration and endotoxin removal was applied to CFT073Δ4. Protein purity and integrity was assessed using SDS-PAGE, Western blots with anti-flagellin antisera, and native-PAGE. We also generated a fliC-deficient strain, CFT073Δ4ΔfliC, to enable the concurrent preparation of a suitable carrier control to be applied in downstream assays. Innate immune stimulation was examined by exposing J774A.1 macrophages to 0.05-1 μg of purified FliC for 5 h; the supernatants were analyzed for cytokines known to be induced by flagella, including TNF-α, IL-6, and IL-12; the results were assessed in the context of prior literature. Macrophage responses to purified FliC encompassed significant levels of several cytokines consistent with prior literature reports. The purification method described here establishes a new approach to examine highly purified FliC in the context of host-pathogen interaction model systems

The Simons Observatory: Magnetic Shielding Measurements for the Universal Multiplexing Module

The Simons Observatory (SO) includes four telescopes that will measure the temperature and polarization of the cosmic microwave background using over 60,000 highly sensitive transition-edge bolometers (TES). These multichroic TES bolometers are read out by a microwave RF SQUID multiplexing system with a multiplexing factor of 910. Given that both TESes and SQUIDs are susceptible to magnetic field pickup and that it is hard to predict how they will respond to such fields, it is important to characterize the magnetic response of these systems empirically. This information can then be used to limit spurious signals by informing magnetic shielding designs for the detectors and readout. This paper focuses on measurements of magnetic pickup with different magnetic shielding configurations for the SO universal multiplexing module (UMM), which contains the SQUIDs, associated resonators, and TES bias circuit. The magnetic pickup of a prototype UMM was tested under three shielding configurations: no shielding (copper packaging), aluminum packaging for the UMM, and a tin/lead-plated shield surrounding the entire dilution refrigerator 100 mK cold stage. The measurements show that the aluminum packaging outperforms the copper packaging by a shielding factor of 8-10, and adding the tin/lead-plated 1K shield further increases the relative shielding factor in the aluminum configuration by 1-2 orders of magnitude.Comment: 7 pages, 4 figure, conference proceedings submitted to the Journal of Low Temperature Physic

Streptococcus agalactiae glyceraldehyde-3-phosphate dehydrogenase (GAPDH) elicits multiple cytokines from human cells and has a minor effect on bacterial persistence in the murine female reproductive tract

Streptococcus agalactiae glyceraldehyde 3-phosphate dehydrogenase (GAPDH), encoded by gapC, is a glycolytic enzyme that is associated with virulence and immune-mediated protection. However, the role of GAPDH in cellular cytokine responses to S. agalactiae, bacterial phagocytosis and colonization of the female reproductive tract, a central host niche, is unknown. We expressed and studied purified recombinant GAPDH (rGAPDH) of S. agalactiae in cytokine elicitation assays with human monocyte-derived macrophage, epithelial cell, and polymorphonuclear leukocyte (PMN) co-culture infection models. We also generated a S. agalactiae mutant that over-expresses GAPDH (oeGAPDH) from gapC using a constitutively active promoter, and analyzed the mutant in murine macrophage antibiotic protection assays and in virulence assays in vivo, using a colonization model that is based on experimental infection of the reproductive tract in female mice. Human cell co-cultures produced interleukin (IL)-1β, IL-6, macrophage inflammatory protein (MIP)-1, tumor necrosis factor (TNF)-α and IL-10 within 24 h of exposure to rGAPDH. PMNs were required for several of these cytokine responses. However, over-expression of GAPDH in S. agalactiae did not significantly affect measures of phagocytic uptake compared to an empty vector control. In contrast, oeGAPDH-S. agalactiae showed a small but statistically significant attenuation for persistence in the reproductive tract of female mice during the chronic phase of infection (10–28 days post-inoculation), relative to the vector control. We conclude that S. agalactiae GAPDH elicits production of multiple cytokines from human cells, and over-expression of GAPDH renders the bacterium more susceptible to host clearance in the female reproductive tract. One-sentence summary: This study shows Streptococcus agalactiae glyceraldehyde 3-phosphate dehydrogenase, an enzyme that functions in glycolysis, gluconeogenesis and virulence, modifies phagocytosis outcomes, including cytokine synthesis, and affects bacterial persistence in the female reproductive tract

Genome-wide mapping of cystitis due to Streptococcus agalactiae and Escherichia coli in mice identifies a unique bladder transcriptome that signifies pathogen-specific antimicrobial defense against urinary tract infection

The most common causes of urinary tract infections (UTIs) are Gram-negative pathogens such as Escherichia coli; however, Gram-positive organisms, including Streptococcus agalactiae, or group B streptococcus (GBS), also cause UTI. In GBS infection, UTI progresses to cystitis once the bacteria colonize the bladder, but the host responses triggered in the bladder immediately following infection are largely unknown. Here, we used genome-wide expression profiling to map the bladder transcriptome of GBS UTI in mice infected transurethrally with uropathogenic GBS that was cultured from a 35-year-old women with cystitis. RNA from bladders was applied to Affymetrix Gene-1.0ST microarrays; quantitative reverse transcriptase PCR (qRT-PCR) was used to analyze selected gene responses identified in array data sets. A surprisingly small significant-gene list of 172 genes was identified at 24 h; this compared to 2,507 genes identified in a side-by-side comparison with uropathogenic E. coli (UPEC). No genes exhibited significantly altered expression at 2 h in GBS-infected mice according to arrays despite high bladder bacterial loads at this early time point. The absence of a marked early host response to GBS juxtaposed with broad-based bladder responses activated by UPEC at 2 h. Bioinformatics analyses, including integrative system-level network mapping, revealed multiple activated biological pathways in the GBS bladder transcriptome that regulate leukocyte activation, inflammation, apoptosis, and cytokine-chemokine biosynthesis. These findings define a novel, minimalistic type of bladder host response triggered by GBS UTI, which comprises collective antimicrobial pathways that differ dramatically from those activated by UPEC. Overall, this study emphasizes the unique nature of bladder immune activation mechanisms triggered by distinct uropathogens

The CCAT-Prime Submillimeter Observatory

The Cerro Chajnantor Atacama Telescope-prime (CCAT-prime) is a new 6-m, off-axis, low-emissivity, large field-of-view submillimeter telescope scheduled for first light in the last quarter of 2021. In summary, (a) CCAT-prime uniquely combines a large field-of-view (up to 8-deg), low emissivity telescope (< 2%) and excellent atmospheric transmission (5600-m site) to achieve unprecedented survey capability in the submillimeter. (b) Over five years, CCAT-prime first generation science will address the physics of star formation, galaxy evolution, and galaxy cluster formation; probe the re-ionization of the Universe; improve constraints on new particle species; and provide for improved removal of dust foregrounds to aid the search for primordial gravitational waves. (c) The Observatory is being built with non-federal funds (~ \$40M in private and international investments). Public funding is needed for instrumentation (~ \$8M) and operations (\$1-2M/yr). In return, the community will be able to participate in survey planning and gain access to curated data sets. (d) For second generation science, CCAT-prime will be uniquely positioned to contribute high-frequency capabilities to the next generation of CMB surveys in partnership with the CMB-S4 and/or the Simons Observatory projects or revolutionize wide-field, sub-millimetter line intensity mapping surveys.Comment: Astro2020 APC White Pape