Interactions between Euwallacea Ambrosia Beetles, Their Fungal Symbionts and the Native Trees They Attack in the Eastern United States

In a globalized world, wood products are constantly being shipped from one location to another, along with tiny hitchhikers in the form of insects and microorganisms. Euwallacea validus is a fungus-farming ambrosia beetle native to East Asia that likely made its way to the United States in wood packaging materials in the latter half of the twentieth century. E. validus cultivates two fungal symbionts in the U.S., an unnamed Fusarium sp. (AF-4) and Raffaelea subfusca. Fusarium symbionts of Euwallacea ambrosia beetles as well as Raffaelea symbionts of closely related ambrosia beetles have incited widespread disease on more than one-hundred hosts worldwide. To resolve host range of Fusarium and Raffaelea symbionts from E. validus, inoculation studies, which mimicked natural infestation by creating numerous beetle-size holes along single stems, were conducted on twelve tree species native to the eastern United States known to be natural hosts for this beetle species. Four months post-inoculation, trees were destructively sampled to examine and measure symptoms associated with inoculation. Results of this study showed significant differences in canker incidence and mean streaking associated with inoculation sites, although neither Fusarium sp. AF-4 nor Raffealea symbionts caused significant disease on any host tested and do not appear to pose serious risks to the known hosts within the invaded range of this beetle. Nonetheless several other Euwallacea-Fusarium consortia have been introduced into the U.S. recently which do pose serious risks to avocado production and forest health. PCR multiplexes were recently developed to discriminate closely related AFC symbionts present in the U.S. to monitor their spread and have opened the door for widespread molecular surveillance. This includes testing whether fusaria differ between the native / invaded ranges of these beetles and if symbiont swapping is occurring between beetles whose ranges currently overlap in the U.S. Results of this study confirmed fidelity between certain Euwallacea sp. and their fungal partners such as E. validus and its symbiont, Fusarium sp. AF-4 in both South Korea and the U.S. with no evidence of additional AFC members despite uncovering other FSSC members within mycangial communities. No other Euwallacea spp. examined exhibited obvious fidelity between native and invaded ranges. Surprisingly, a number of known AFC lineages already existing in the U.S. were uncovered from the mycangia of other Euwallacea spp. within the geographic origin of beetles in East Asia. In addition to AFC members, other FSSC isolates were associated with galleries of all five Euwallacea spp. studied, indicating frequent interactions between symbiotic and asymbiotic FSSC members. These results uncovered widespread fungal infidelity among closely related Euwallacea beetles. Such novel beetle-fungus combinations could incite disease across a number of orchard, landscape, and forest trees

Embedded-Cluster Calculations in a Numeric Atomic Orbital Density-Functional Theory Framework

We integrate the all-electron electronic structure code FHI-aims into the general ChemShell package for solid-state embedding (QM/MM) calculations. A major undertaking in this integration is the implementation of pseudopotential functionality into FHI-aims to describe cations at the QM/MM boundary through effective core potentials and therewith prevent spurious overpolarization of the electronic density. Based on numeric atomic orbital basis sets, FHI-aims offers particularly efficient access to exact exchange and second order perturbation theory, rendering the established QM/MM setup an ideal tool for hybrid and double-hybrid level DFT calculations of solid systems. We illustrate this capability by calculating the reduction potential of Fe in the Fe-substituted ZSM-5 zeolitic framework and the reaction energy profile for (photo-)catalytic water oxidation at TiO2(110).Comment: 12 pages, 4 figure

Response and Resistance to Paradox-Breaking BRAF Inhibitor in Melanomas

FDA-approved BRAF inhibitors produce high response rates and improve overall survival in patients with BRAF V600E/K-mutant melanoma, but are linked to pathologies associated with paradoxical ERK1/2 activation in wild-type BRAF cells. To overcome this limitation, a next-generation paradox-breaking RAF inhibitor (PLX8394) has been designed. Here, we show that by using a quantitative reporter assay, PLX8394 rapidly suppressed ERK1/2 reporter activity and growth of mutant BRAF melanoma xenografts. Ex vivo treatment of xenografts and use of a patient-derived explant system (PDeX) revealed that PLX8394 suppressed ERK1/2 signaling and elicited apoptosis more effectively than the FDA-approved BRAF inhibitor, vemurafenib. Furthermore, PLX8394 was efficacious against vemurafenibresistant BRAF splice variant-expressing tumors and reduced splice variant homodimerization. Importantly, PLX8394 did not induce paradoxical activation of ERK1/2 in wild-type BRAF cell lines or PDeX. Continued in vivo dosing of xenografts with PLX8394 led to the development of acquired resistance via ERK1/2 reactivation through heterogeneous mechanisms; however, resistant cells were found to have differential sensitivity to ERK1/2 inhibitor. These findings highlight the efficacy of a paradox-breaking selective BRAF inhibitor and the use of PDeX system to test the efficacy of therapeutic agents. © 2017 American Association for Cancer Research

Critical Collapse of the Massless Scalar Field in Axisymmetry

We present results from a numerical study of critical gravitational collapse of axisymmetric distributions of massless scalar field energy. We find threshold behavior that can be described by the spherically symmetric critical solution with axisymmetric perturbations. However, we see indications of a growing, non-spherical mode about the spherically symmetric critical solution. The effect of this instability is that the small asymmetry present in what would otherwise be a spherically symmetric self-similar solution grows. This growth continues until a bifurcation occurs and two distinct regions form on the axis, each resembling the spherically symmetric self-similar solution. The existence of a non-spherical unstable mode is in conflict with previous perturbative results, and we therefore discuss whether such a mode exists in the continuum limit, or whether we are instead seeing a marginally stable mode that is rendered unstable by numerical approximation.Comment: 11 pages, 8 figure

A Climatology of Northwest Missouri Snowfall Events: Long Term Trends and Interannual Variability.

The goal of this study was to develop a 50-year statistical climatology of snowfall occurrences using data from a dense network of cooperative station observations covering northwest and central Missouri, and these records were provided by the Missouri Climate Center. This included a study of the long term trends and interannual variability in snowfall occurrence as related to sea surface temperature variations in the Pacific Ocean basin associated with the El Nino and Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These trends and variations were then related to four synoptic-scale flow regimes that produce these snowfalls in the Midwest. The results demonstrate that during the snowfall season (Oct - April) the northwest Missouri region can expect about eight snowfall events which produce three or more inches of accumulation. While no significant long-term trend in overall snowfall occurrence was found, a decrease in the number of extreme events (10 or more inches) was noted. Also, fewer snowfall events were found during El Nino years, while more heavy snowfall events occurred during "neutral" years, and these results could be related to synoptic- scale variability. A closer examination of the results demonstrated that El Nino/La Nina related variability in snowfall occurrence was superimposed on longer-term NPO-related variability.This research was supported by the University Corporation for Atmospheric Research (UCAR) Cooperative program for Operational Meteorological Education and Training (COMET) Outreach Programunder award # 98115921

Seagrass Recovery Following Marine Heat Wave Influences Sediment Carbon Stocks

Worldwide, seagrass meadows accumulate significant stocks of organic carbon (C),known as “blue” carbon, which can remain buried for decades to centuries. However,when seagrass meadows are disturbed, these C stocks may be remineralized, leading to significant CO2 emissions. Increasing ocean temperatures, and increasing frequency and severity of heat waves, threaten seagrass meadows and their sediment blue C. To date, no study has directly measured the impact of seagrass declines from high temperatures on sediment C stocks. Here, we use a long-term record of sediment C stocks from a 7-km2, restored eelgrass (Zostera marina) meadow to show that seagrass dieback following a single marine heat wave (MHW) led to significant losses of sediment C. Patterns of sediment C loss and re-accumulation lagged patterns of seagrass recovery. Sediment C losses were concentrated within the central area of the meadow,where sites experienced extreme shoot density declines of 90% during the MHW and net losses of 20% of sediment C over the following 3 years. However, this effect was not uniform; outer meadow sites showed little evidence of shoot declines during the MHW and had net increases of 60% of sediment C over the following 3 years. Overall, sites with higher seagrass recovery maintained 1.7x as much C compared to sites with lower recovery. Our study demonstrates that while seagrass blue C is vulnerable to MHWs,localization of seagrass loss can prevent meadow-wide C losses. Long-term (decadal and beyond) stability of seagrass blue C depends on seagrass resilience to short-term disturbance events

Genome-scale analysis identifies paralog lethality as a vulnerability of chromosome 1p loss in cancer.

Functional redundancy shared by paralog genes may afford protection against genetic perturbations, but it can also result in genetic vulnerabilities due to mutual interdependency1-5. Here, we surveyed genome-scale short hairpin RNA and CRISPR screening data on hundreds of cancer cell lines and identified MAGOH and MAGOHB, core members of the splicing-dependent exon junction complex, as top-ranked paralog dependencies6-8. MAGOHB is the top gene dependency in cells with hemizygous MAGOH deletion, a pervasive genetic event that frequently occurs due to chromosome 1p loss. Inhibition of MAGOHB in a MAGOH-deleted context compromises viability by globally perturbing alternative splicing and RNA surveillance. Dependency on IPO13, an importin-β receptor that mediates nuclear import of the MAGOH/B-Y14 heterodimer9, is highly correlated with dependency on both MAGOH and MAGOHB. Both MAGOHB and IPO13 represent dependencies in murine xenografts with hemizygous MAGOH deletion. Our results identify MAGOH and MAGOHB as reciprocal paralog dependencies across cancer types and suggest a rationale for targeting the MAGOHB-IPO13 axis in cancers with chromosome 1p deletion

Hysteresis and Avalanches in the Random Anisotropy Ising Model

The behaviour of the Random Anisotropy Ising model at T=0 under local relaxation dynamics is studied. The model includes a dominant ferromagnetic interaction and assumes an infinite anisotropy at each site along local anisotropy axes which are randomly aligned. Two different random distributions of anisotropy axes have been studied. Both are characterized by a parameter that allows control of the degree of disorder in the system. By using numerical simulations we analyze the hysteresis loop properties and characterize the statistical distribution of avalanches occuring during the metastable evolution of the system driven by an external field. A disorder-induced critical point is found in which the hysteresis loop changes from displaying a typical ferromagnetic magnetization jump to a rather smooth loop exhibiting only tiny avalanches. The critical point is characterized by a set of critical exponents, which are consistent with the universal values proposed from the study of other simpler models.Comment: 40 pages, 21 figures, Accepted for publication in Phys. Rev.