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Investigating the Impact of \u3ci\u3eHelicobacter pylori\u3c/i\u3e Glycan Biosynthesis on Host Immune Response
No full textHelicobacter pylori is a pathogenic bacterium that utilizes its surface glycans to modulate its interactions with host cells. H. pylori incorporates Lewis blood group tetrasaccharide antigens at the terminus of its lipopolysaccharide to mimic mammalian glycans of a host cell and glycosylates specialized proteins to facilitate its adhesion to the epithelium. This study tests the hypothesis that genetic disruption of glycan biosynthesis will negate the modulatory effects of H. pylori’s glycans and reduce the bacterium’s pathogenicity. Namely, we test the hypothesis that phase variable expression of certain carbohydrate epitopes within H. pylori’s glycocalyx accounts for variable immune response to different glycosylation mutant strains. We additionally test the hypothesis that disrupted glycan biosynthesis will inhibit effective bacterial cell adhesion. These hypotheses were tested by investigating H. pylori’s phase variable glycan architecture in parallel with the induced immune response and adhesion of different glycosylation mutant strains compared to wildtype H. pylori. Our results suggest that LPS elaboration, rather than Lewis Y antigen expression, correlates with the induced immune response of gastric epithelial cells and dendritic cells. We additionally conclude that adhesion of H. pylori to gastric epithelial cells is mediated by the glycan biosynthetic pathway
Lake water chemistry and local adaptation shape NaCl toxicity in Daphnia ambigua
No full textIncreasing application of road deicing agents (e.g., NaCl) has caused widespread salinization of freshwater environments. Chronic exposure to toxic NaCl levels can impact freshwater biota at genome to ecosystem scales, yet the degree of harm caused by road salt pollution is likely to vary among habitats and populations. The background ion chemistry of freshwater environments may strongly impact NaCl toxicity, with greater harm occurring in ion-poor, soft water conditions. In addition, populations exposed to salinization may evolve increased NaCl tolerance. Notably, if organisms are adapted to their natal lake water chemistry, toxicity responses may also vary among populations in a given test medium. We examined how this evolutionary and environmental context may interact in shaping NaCl toxicity with a pair of laboratory reciprocal transplant toxicity experiments, using natural populations of the water flea Daphnia ambigua from three lakes differing in ion availability. The lake water environment strongly influenced NaCl toxicity in both trials. NaCl greatly reduced reproduction and r in lake water from a low-ion/ calcium-poor environment compared with water from both a calcium-rich lake and an ion-rich coastal lake. Daphnia from this coastal lake were most robust to the effects of NaCl. A significant population x environment interaction shaped survival in both trials, suggesting that local adaptation to the test waters used contributed to toxicity responses. Our findings that the lake water environment, adaptation to that environment, and adaptation to a focal contaminant may shape toxicity demonstrate the importance of considering environmental and biological complexity in mitigating pollution impacts
In situ HCR in non-traditional arthropods
No full textVisualizing the expression of genes is a fundamental tool in molecular biology. Traditional colorimetric in situ hybridization using long RNA probes has been a staple for visualizing gene expression but has many drawbacks. In situ HCR v3.0, developed by Choi et. al. 2018, offers improvements over traditional in situs in nearly every aspect: probes can simply be ordered rather than painstakingly cloned and transcribed, which also makes them cost-effective; an HCR takes just three days to complete rather than five or more days; HCR is robust and works well for first-time users; and HCR probes can be multiplexed, allowing four to eight genes to be visualized in a single sample. HCR has been used successfully in many arthropods, including insects (Drosophila, Tribolium), crustaceans (Parhyale, Daphnia, Artemia), and chelicerates (Limulus horseshoe crab, Acanthoscurria tarantula). In this demo, you will learn how to design and order HCR probes as well as best practices for experimental design
The H.C. Carey School of U.S. Currency Doctors: A Subtle Principle and its Progeny
Full text linkHenry C. Carey led a school of post-Civil War U.S. currency doctors prescribing an “elastic currency,” expanding and contracting according to commercial needs. The problem for the Careyites was reconciling elasticity, which implied inconvertibility with gold, with the related aim of decentralized financial power. Careyite currency doctors included, among others, Wallace P. Groom, editor of the New York Mercantile Journal, and Henry Carey Baird, Carey’s own nephew and inheritor of his mantle. Their prescribed reform of the banking system featured a financial innovation that would remove superfluous currency from circulation while supplying what was needed. The innovation was an “interconvertible bond,” a debt instrument of the U.S. Treasury that was to be issued upon demand and redeemable for currency at the option of the holder. Its function was supposed to be like the mechanical governor of a steam engine, operating by a “subtle principle” that obviated human governing power and discretion. The Carey school’s prescription and its rationale remained salient up to the advent of the Federal Reserve System
Radical and Liberal Approaches to Gay Rights Organizing from Stonewall to AIDS
No full textPride parades today celebrate the Stonewall riots of 1969 as the first time homosexuals fought back. They mark Stonewall as the beginning of the gay rights movement. While many historians take care to show that Stonewall was part of a longer history of gay rights organizing, few highlight the tension and division surrounding the 1969 riots. The celebration of Stonewall was not a foregone conclusion. In fact, leading gay rights organizations at the time denounced the riots and pleaded for calm in the gay community. The celebration of the anniversary of Stonewall was the result of concerted effort by radical gay activists and a sign of their consolidation of power within the movement in the early 1970s. This thesis seeks to reframe Stonewall as a key moment of transition for radical activists and part of a central divide in the gay rights movement between liberal and radical organizers. This thesis traces the tension between liberals and radicals through three important transfers of power in the gay rights movement: Stonewall; the liberal response to Anita Bryant in 1977 and 1978; and the eruption of radical organizing through ACT-UP during the AIDS crisis. By studying these three essential moments of tension and transition, I find that the division between the radical and liberal gay organizers was not a mere difference of tactics or political attitudes, but a division over two fundamentally different and opposing definitions of homosexuality
Effects of the plasticizer tributyl phosphate (TBP) on the intrinsic properties of mammalian lumbar motor neurons
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Origin of Rhyolite from Magma Mush: Plutonic Lithics from the Ohakuri Ignimbrite, Taupō Volcanic Zone, New Zealand
No full textDetermining how silicic magma is generated and how the crust accommodates large volumes of magma is challenging because only the erupted products of a magma system are accessible. One model being tested suggests that silicic magma is extracted from a crystal-rich, melt-bearing magma mush. Plutonic lithics (coarse-grained crystalline rock fragments) may be sourced from this magma mush or from surrounding crustal material. Extracted plutonic lithics were collected from the Ohakuri ignimbrite of the Central Taupō Volcanic Zone (TVZ), New Zealand, where high rates of rhyolitic magma erupt explosively forming large calderas. Some of the plutonic lithics have minor element signatures similar to the Ohakuri pumice and are interpreted as being sourced from the underlying reservoir of magma mush. Other plutonic lithics from the Ohakuri ignimbrite have geochemical signatures similar to Whakamaru, an older volcanic system, and are interpreted to be crustal fragments brought up by the force of the Ohakuri eruption. The magma mush lithics are enriched in compatible major elements relative to Ohakuri pumice and comprise a framework of phenocrysts surrounded by granophyre. Notably the composition of granophyre is more evolved than the pumice suggesting it may be the crystallized product of remnant interstitial melt. Pressures modeled for the granophyre using rhyolite-MELTs geobarometry are similar to the extraction pressures modeled for the Ohakuri pumice glass. The combination of the observed textures, geochemical signatures, and calculated pressures, provide the first evidence that granophyre may represent the once potentially extractable liquid component of magma mush within large silicic volcanic systems
