Native Sites Research Articles

Buffer effects on site directed Cu2+-labeling using the double histidine motif

The double histidine, or dHis, motif has emerged as a powerful spin labeling tool to determine the conformations and dynamics, subunit orientation, native metal binding site location, and other physical characteristics of proteins by Cu2+-based electron paramagnetic resonance. Here, we investigate the efficacy of this technique in five common buffer systems, and show that buffer choice can impact the loading of Cu2+-NTA into dHis sites, and more generally, the sensitivity of the overall technique. We also present a standardized and optimized examination of labeling of the dHis motif with Cu2+-NTA for EPR based distance measurements. We provide optimal loading procedures, using representative EPR and UV/Vis data for each step in the process. From this data, we find that maximal dHis loading can be achieved in under 30 min with low temperature sample incubation. Using only these optimal procedures, we see up to a 28% increase in fully labeled proteins compared to previously published results in N-ethylmorpholine. Using both this optimized procedure as well as a more optimal buffer, we can achieve up to 80% fully loaded proteins, which corresponds to a 64% increase compared to the prior data. These results provide insight and deeper understanding of the dHis Cu2+-NTA system, the variables that impact its efficacy, and present a method by which these issues may be mitigated for the most efficient labeling.

Physiological effects of mature tree transplanting characterize the roles of the soil-root interface in the field

The intimate connection between roots and soil particles is a prerequisite for the continuous flow of water and nutrients from soil to trees, and carbon flow from roots to the rhizosphere. The soil-root interface has been studied in multiple laboratory and greenhouse experiments. Yet its multiple roles and their differential contributions to tree health have rarely been experimentally studied on mature trees in the field.We took advantage of mature olive tree transplanting to test the physiological effects of breakage of the soil-root interface in situ. Eight olive trees were monitored following transplantation into a site located 4 km from their native site, along two years. Additional eight trees were monitored simultaneously at the native site, as control. To decrease mortality risk, transplanted trees were heavily pruned before transplanting, and were irrigated and fertilized in their new site.Transplanted trees had ~50% lower rates of leaf photosynthesis and transpiration; ~80% lower root starch content; and ~30% higher loss of xylem conductivity, than native trees. Leaf water potential (LWP) was similar across trees, becoming more negative in the transplanted trees only in the second year following transplanting. While starch content and xylem conductivity recovered in the second year, leaf gas exchange and LWP remained significantly lower than in native trees. Soil P and K were higher under transplanted trees that remained stressed than under trees that recovered.Breakage of the soil-root interface caused a multi-system stress to trees. The lack of persistent LWP response might indicate that loss of hydraulic conductivity was driven by root, rather than aboveground, embolisms. Degradation of starch in the roots indicates an increase in belowground sinks. In the long run, recovery of starch content means no carbon limitation; yet the prevailing effects on leaf activities suggest a long-term stress unrelated with water or carbon supply.

Proton and deuteron electrodiffusion in a D263T borosilicate glass by controlled charge attachment from a fs-plasma

The femtosecond laser plasma charge attachment induced transport (fs-plasma CAIT) technique is considerably extended and applied to study ion transport in a borosilicate glass. The technique is based on attaching polarity selected charge carriers from a fs-laser to the front side of a sample, which induces transport of mobile charge carriers in this sample. The plasma-CAIT spectrometer is placed into a housing allowing the control of the plasma medium and its pressure. A model system is described, which allows the determination of the internal resistance of the plasma. This in turn provides access to absolute ionic conductivities without the need of external calibration. The improved fs-plasma CAIT technique is applied to study alkali ion conductivity in a D263T glass by attachment of protons or deuterons from a hydrogen and deuterium plasma, respectively. The range of conductivities is extended by one and a half orders of magnitude compared to previous work. Ex-situ analysis of the irradiated D263T samples by time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed a replacement of sodium and potassium ions being the native mobile charge carriers in the glass by external proton and deuterons, respectively, over up-to 100 nm. The concentration depth profiles generated by the electrodiffusion involve a local pile-up of the potassium concentration above the bulk concentration and a concomitant further depletion of the faster sodium at the H+ / D+ diffusion front. The results are fully in line with previous observation in a Cs+ CAIT experiment. The significant advancement of the current work lies in the demonstration that alkali ion transport can be probed by using protons or deuterons as markers for replacement in the native sites of the alkali ions. Ultimately the plasma medium can be freely chosen from a large range of chemical species turning the plasma-CAIT technique into an almost universal tool to study DC transport in solid ionics.

Demonstrating the Impact of 6to4 Tunneling on IPV4 and IPV6 Network Coexistence

In this work the impact of the 6to4 tunnels is considered. In order for traffic to flow from an Internet Protocol version 4(IPv4) website to a native Internet Protocol version 6(IPv6) website, an additional configuration must be added to the network, as this cannot be done by default. The Riverbed Modeler Academic Version 17.5 is used to build and evaluate network efficiency with optimized 6to4 tunnels. The performance of the network is assessed based on the traffic received and sent by Internet Protocol (Version 6), Voice Called Traffic and the Sent and Received Traffic of the configured applications. The flow of traffic from servers to workstations in native IPv6 sites shows the effect of the tunnel configured.

Prevention of Tobacco Carcinogen-Induced Lung Tumor Development by a Novel STAT3 Decoy Inhibitor.

The STAT3 pathway is frequently overactive in non-small cell lung cancer (NSCLC), an often fatal disease with known risk factors including tobacco and chemical exposures. Whether STAT3 can be downmodulated to delay or prevent development of lung cancer resulting from an environmental exposure has not been previously tested. A circular oligonucleotide STAT3 decoy (CS3D) was used to treat mice previously exposed to the tobacco carcinogen nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. CS3D contains a double-stranded STAT3 DNA response element sequence and interrupts STAT3 signaling by binding to STAT3 dimers, rendering them unable to initiate transcription at native STAT3 DNA binding sites. An intermittent course of CS3D decreased the development of airway preneoplasias by 42% at 1 week posttreatment, reduced the progression of preneoplasia to adenomas by 54% at 8 weeks posttreatment, and reduced the size and number of resulting lung tumors by 49.7% and 29.5%, respectively, at 20 weeks posttreatment. No toxicity was detected. A mutant cyclic oligonucleotide with no STAT3 binding ability was used as a control. Chemopreventive effects were independent of the KRAS mutational status of the tumors. In lungs harvested during and after the treatment course with CS3D, airway preneoplasias had reduced STAT3 signaling. Chemopreventive effects were accompanied by decreased VEGFA expression, ablated IL6, COX-2, and p-NF-κB, and decreased pulmonary M2 macrophages and myeloid-derived suppressor cells. Thus, downmodulation of STAT3 activity using a decoy molecule both reduced oncogenic signaling in the airway epithelium and favored a lung microenvironment with reduced immunosuppression.

Atomic Insights into Aluminium-Ion Insertion in Defective Anatase for Batteries.

Aluminium batteries constitute a safe and sustainable high-energy-density electrochemical energy-storage solution. Viable Al-ion batteries require suitable electrode materials that can readily intercalate high-charge Al3+ ions. Here, we investigate the Al3+ intercalation chemistry of anatase TiO2 and how chemical modifications influence the accommodation of Al3+ ions. We use fluoride- and hydroxide-doping to generate high concentrations of titanium vacancies. The coexistence of these hetero-anions and titanium vacancies leads to a complex insertion mechanism, attributed to three distinct types of host sites: native interstitial sites, single vacancy sites, and paired vacancy sites. We demonstrate that Al3+ induces a strong local distortion within the modified TiO2 structure, which affects the insertion properties of the neighbouring host sites. Overall, specific structural features induced by the intercalation of highly polarising Al3+ ions should be considered when designing new electrode materials for polyvalent batteries.

Chinese privet (Ligustrum sinense Lour.) alters the timing of litterfall and nutrient quality of leaf litter inputs in invaded riparian forests

The invasive non-native shrub Chinese privet occupies riparian forests throughout the southeastern US however little is known regarding its ability to impact ecosystem processes. This study aimed to characterize phenological patterns of privet litterfall, litter chemistry, and changes in availability of mobile soil nutrients within riparian zones invaded by privet. Comparisons of native and invaded sites showed that privet invasion alters the timing but not quantity of litter deposition. In contrast to native species, total privet litterfall displayed little seasonal variation however invaded sites had similar total litter mass compared to native sites. Within invaded sites privet litter was 26% of total litterfall in spring. Privet leaf litter was seasonally enriched in nitrogen during winter as compared to fall and spring. Compared to native sites, invaded sites had significantly increased soil nitrate availability and decreased soil carbon:nitrogen ratios. In contrast, dissolved organic matter and dissolved nitrogen in soil solution was lower in invaded compared to native sites. Results suggest that privet enhances litter and inorganic nitrogen availability in ways that have potential to impact decomposer and detritovore communities in the riparian zone and adjacent aquatic systems.

Soil carbon storage and carbon sources under different Spartina alterniflora invasion periods in a salt marsh ecosystem

As an important component of global change, plant invasion threaten the sustainability of global ecosystems and may alter the carbon dynamics in the invaded area. Knowledge of the effects of Spartina alterniflora invasion on soil organic carbon (SOC) and soil inorganic carbon (SIC) stocks and their profile distribution is limited in coastal salt marshes, which are referred as important “blue carbon” ecosystems. A short-term invasion chronosequence of 2–10 years was used to evaluate the responses of SOC and SIC over the invasion period in the Yellow River Estuary, China. The 13C isotope content was analyzed in soil, plant tissue, and sediment debris to infer the contribution of invasion to SOC accumulation in the invaded salt marshes. The results showed that more than 80% of the soil C was inorganic, and this percentage was higher in native sites and in the newly invaded areas. SOC accumulated linearly with the invasive time in the top 100 cm soil. The SOC accumulation rate varied along the soil profile, and was 0.10, 0.13, and 0.40 kg C m−2 yr−1 in the top 20cm, 40cm, 100cm soils, respectively. The 13C isotope analysis demonstrated that debris-derived C was dominant in the native salt marshes (62.2% on average), while plant-derived C increased with the invasive time. Structural equation modeling (SEM) showed that the SIC loss in the top 40 cm with invasion could be indirectly attributed to the soil acidification in the alkaline soil and directly related to soil Ca loss. Our results also suggested that SIC loss would partially offset the CO2 sequestration associated with SOC burial caused by the invasion. This work indicates causal relationships between plant invasions and soil carbon pools and highlights the nonnegligible importance of inorganic C in coastal blue carbon budgets.

Partial clearing of a road corridor leads to homogenisation of the invertebrate fauna

A recent plan to extend a highway in south-west Western Australia has been abandoned, but not before a 10–200m wide strip of vegetation along the alignment had been cleared. Attempts are now being made to rehabilitate the cleared area. The aim of this paper is 2-fold. First, it documents the changes in invertebrate abundance, richness and evenness in this abandoned landmark development. Second, it explores the changes in invertebrate species composition, concentrating on ants, in terms of known trends in biodiversity, with particular emphasis on biotic homogenisation. We report on the immediate changes in invertebrate assemblages from a spatial continuum of sites passing through six discrete woodland communities. A total of 69 species of ants were sampled by pitfall traps from the sites, with 50 being sampled in the 7 reference sites and 46 in the 13 cleared sites. As far as most of these simple indices are concerned, the previously cleared areas generally exhibited values that are not appreciably different from those of the reference sites, except that species richness was marginally higher in the reference sites and ant abundance was higher in the cleared area sites. There was considerable variation in numbers of ant species within Ant Niche Template categories in both the reference and cleared area sites. However, numbers of nest specialists and trophic specialists were significantly lower in cleared area sites; opportunistic species and one generalist were more abundant in cleared areas. The two-dimensional solution of the multi-dimensional scaling ordination grouped all cleared sites close together, with the reference sites and modified native vegetation site being widely scattered across the graph. The tight bunching of the cleared sites suggests that clearing for the proposed highway has resulted in homogenising the ant fauna, creating a characteristic assemblage that differed from all of the original reference sites. When considered at the ordinal level, significantly less Clitellata (worms), Malacostraca (slaters), Araneae (spiders), Blattodea (cockroaches), Dermaptera (earwigs) and Coleoptera (beetles) were sampled from the cleared sites, but significantly more Collembola (springtails), Homoptera and Heteroptera (both types of sucking bugs) were sampled in these sites. Collembola may be responding to the abundance of exotic grasses whereas the sucking bugs may have benefitted from the lush herb and shrub layer associated with the regrowth and rehabilitation efforts.

Pursuing the Elixir of Life: In Vivo Antioxidative Effects of Manganosalen Complexes.

Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have been shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess reactive oxygen species (ROS), thereby restoring the redox balance in damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. These disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory, and cardiovascular diseases; tissue injury; and other damages related to the liver, kidney, or lungs.

Variant effect on splicing regulatory elements, branchpoint usage, and pseudoexonization: Strategies to enhance bioinformatic prediction using hereditary cancer genes as exemplars.

It is possible to estimate the prior probability of pathogenicity for germline disease gene variants based on bioinformatic prediction of variant effect/s. However, routinely used approaches have likely led to the underestimation and underreporting of variants located outside donor and acceptor splice site motifs that affect messenger RNA (mRNA) processing. This review presents information about hereditary cancer gene germline variants, outside native splice sites, with experimentally validated splicing effects. We list 95 exonic variants that impact splicing regulatory elements (SREs) in BRCA1, BRCA2, MLH1, MSH2, MSH6, and PMS2. We utilized a pre-existing large-scale BRCA1 functional data set to map functional SREs, and assess the relative performance of different tools to predict effects of 283 variants on such elements. We also describe rare examples of intronic variants that impact branchpoint (BP) sites and create pseudoexons. We discuss the challenges in predicting variant effect on BP site usage and pseudoexonization, and suggest strategies to improve the bioinformatic prioritization of such variants for experimental validation. Importantly, our review and analysis highlights the value of considering impact of variants outside donor and acceptor motifs on mRNA splicing and disease causation.

Sustainable Neighborhood Public Outreach: I-95 GIR Archaeological Investigations in Philadelphia

ABSTRACTThe Pennsylvania Department of Transportation and the Federal Highway Administration are undertaking a long-term, multiphase project to improve and rebuild Interstate 95 (I-95) in Pennsylvania, within the historic city of Philadelphia. Given the complex urban setting, the archaeological subsurface testing for the I-95 Girard Avenue Interchange Improvement Project is being guided by a programmatic agreement under Section 106 of the National Historic Preservation Act and a categorical exclusion under the National Environmental Policy Act. Through data-recovery excavations, the contractor for the project, AECOM, has documented 30 historical-period and Native American archaeological sites. The project includes its own professional journal, live interactive reporting, and a public archaeology center.

A radial force-independent bioprosthesis for transcatheter tricuspid valve implantation in a preclinical model

BackgroundInterventional treatments of tricuspid regurgitation have been emerging as minimally invasive alternatives. Among those reported transcatheter tricuspid devices, the radial force between the device and native tricuspid annulus is the common principle to be employed for device immobilization. However, this immobilization mechanism may potentially lead to adverse consequences. We developed a radial force-independent stent valve device for implantation at native tricuspid annular site without inducing stress on either myocardial tissue or the bioprosthesis. MethodsWe designed a radial force-independent LuX-Valve as a transcatheter bioprosthesis, comprising a stent valve and a delivery system. The device employs a combination of a right ventricle anchoring component, two leaflet-grasping clips, and an atrial disc as a mechanical integrity to immobilize the stent valve device in secure at the native tricuspid annulus. We evaluated the feasibility and safety of implantation of this device in a goat model. ResultsWe successfully implanted LuX-Valves at the tricuspid position through the right atrium in 17 goats. Procedures in 16 cases were safe. Time for the operator to implant the device until immobilization in secure ranged from 3.5 to 10 min. No significant paravalvular leakage was detected by echocardiography during follow-up, up to 180 days. Histopathology showed no evidence of stent fracture and myocardial injury. ConclusionThe results indicated that radial force-independent LuX-Valve was safe and practicable for tricuspid valve implantation with satisfactory prosthetic function.

Community turnover provides insight into variable invertebrate recovery between restored streams with different integrated catchment management plans

ABSTRACT Understanding temporal patterns in restored environments is important for identifying potential barriers to recovery and improved management of degraded habitats. In this paper, we use temporal beta diversity analyses to compare invertebrate community recovery trajectories in three restored agricultural stream sites under different integrated catchment plans, a native forest reference site, and two unmodified pasture control stream sites over 24 years. The restored sites diverged from their initial community composition over time and became more similar to the reference site community, which was relatively stable over time. Variation partitioning showed that prior to restoration beta diversity was primarily associated with environmental and spatial drivers, whereas post-restoration beta diversity was more influenced by temporal and environmental drivers, including changes in substrate size, fine sediments, water clarity, and nutrients, as well as temperature and flow regime. Species’ contributions to beta diversity varied between sites and years, with sensitive EPT taxa contributing more in reference and control sites. However, contributions of some EPT species, particularly mayflies, increased in restored sites post-ICM. In summary, after nearly two decades of ICM, restored stream sites show recovery towards reference conditions, yet differences persist, indicating that rehabilitation may take longer, depending on the restoration goals.

Molecular movie of nucleotide binding to a motor protein

BackgroundThe SecA DEAD (Asp-Glu-Ala-Asp) motor protein uses binding and hydrolysis of adenosine triphosphate (ATP) to push secretory proteins across the plasma membrane of bacteria. The reaction coordinate of nucleotide exchange is unclear at the atomic level of detail. MethodsWe performed multiple atomistic computations of the DEAD motor domain of SecA with different occupancies of the nucleotide and magnesium ion sites, for a total of ~1.7 μs simulation time. To characterize dynamics at the active site we analyzed hydrogen-bond networks. ResultsATP and ADP can bind spontaneously at the interface between the nucleotide binding domains, albeit at an intermediate binding site distinct from the native site. Binding of the nucleotide is facilitated by the presence of a magnesium ion close to the glutamic group of the conserved DEAD motif. In the absence of the magnesium ion, protein interactions of the ADP molecule are perturbed. ConclusionsA protein hydrogen-bond network whose dynamics couples to the occupancy of the magnesium ion site helps guide the nucleotide along the nucleotide exchange path. In SecA, release of magnesium might be required to destabilize the ADP binding site prior to release of the nucleotide. General significanceWe identified dynamic hydrogen-bond networks that help control nucleotide exchange in SecA, and stabilize ADP at an intermediate site that could explain slow release. The reaction coordinate of the protein motor involves complex rearrangements of a hydrogen-bond network at the active site, with perturbation of the magnesium ion site likely occurring prior to the release of ADP.

Soil carbon change across ten New South Wales farms under different farm management regimes in Australia

AbstractThis paper examines the potential influence of soil management and land use on soil carbon on cropping farms in New South Wales (NSW), Australia. Soil organic carbon (SOC) data from ten farms spatially distributed across NSW were examined on two occasions. Soil cores to a depth 0–30 cm were measured for SOC and, as expected, SOC in the A horizon (1.16%) was significantly (p < .001) greater than in the B horizon (0.74%) of all profiles. Analysis of the 2013 and 2015 SOC data indicated that in many ways, the results runs counter to other SOC studies in Australia. Importantly, the mean SOC concentration in these agricultural soils was significantly (p < .001) less under cropping (2013‐1.05%, 2015‐0.97%) than in native sites (2013‐1.20%, 2015‐1.16%). Out of the total of 35 sites sampled from 10 farms, SOC in 49% of sites did not change significantly over 2 years, in 17% it increased significantly, whereas in 34% it decreased. Further, a clear implication of drought on SOC was seen on sites that were uncropped based on a critical value for a 95% confidence interval (p < .05) and complemented by the significant correlation (p < .05) between average annual precipitation deficit (ANPD) and SOC across the state with R2 = 0.39. The mean SOC was found to be directly proportional to standard deviation and standard error. In terms of spatial variability, the C0 (nugget) value was greatest for farms with a large mean SOC and the average variogram in this study has a range of approximately 200 m which is potentially useful in determining sampling spacing for soil carbon auditing purpose. Similar empirical data over more years are required to better estimate SOC levels and to determine whether at a farm scale, factors such as land management, land use and climate can be related to soil carbon change and variability.

Influence of Mining and Vegetation Restoration on Soil Properties in the Eastern Margin of the Qinghai-Tibet Plateau.

Mining causes serious destruction of the surface morphology and soil structure of lands, and vegetation restoration on post-mining lands provides an effective way for soil and water conservation. To determine the influence of mining and vegetation restoration on soil properties in the eastern margin of the Qinghai-Tibet Plateau, four land sites, including two vegetation restoration sites (restorated by Elymus nutans and Picea crassifolia, respectively), one non-vegetated mining site and one native grassland site, were selected. Fifty-two topsoil (0–10) samples were collected from these four sites, and then soil properties, trace metals and soil enzyme activities were analyzed. The results showed that there was an increase in soil pH (>8.0) after mining, while vegetation restoration decreased the soil pH compared with native grassland; the soil organic matter and total nitrogen in the site restored with E. nutans increased by 48.8% and 25.17%, respectively, compared with the site restored with P. crassifolia. The soil enzyme activities decreased after mining, and there were no significant increases in urease, phosphatase, β-glucosidase and β-1,4-N-acetylglucosaminidase activities after five years of restoration. In addition, the contents of soil trace metals (cadmium, chromium, mercury, lead and zinc) after mining were lower than the Chinese threshold (GB 15618/2018), but the content of arsenic in non-vegetated soil and P. crassifolia-restored soil exceeded the threshold by 22.61 times and 22.86 times, respectively. Therefore, As-contaminated land areas should be accurately determined and treated in a timely way to prevent arsenic from spreading, and plant species with tolerance to alkaline soil should be selected for vegetation restoration on post-mining lands.

P552Predictors of pacing induced left ventricular dysfunction and cardiomyopathy assessed by three-dimensional echocardiography and speckle tracking strain

Abstract OnBehalf Alexandria EPS Unit Background During recent years there was a focus on the negative effects associated with long term right ventricular (RV) pacing. It was shown in both experimental and clinical studies that RV pacing leads to ventricular dyssynchrony, similar to that of left bundle branch block (LBBB) with subsequent electrical, mechanical and anatomical changes leading to detrimental effects on left ventricular structure and function. During the last two decades, 3D echocardiography developed from a time-consuming method to a routine clinical approach. At present, evidence suggested that 3D echocardiography provided improved accuracy and reproducibility over 2D methods for LV volume and function calculation. There is a growing number of literature signifying that speckle tracking strain is able to identify left ventricular (LV) dysfunction even before any reduction in LV ejection fraction (LVEF). Methods This was an observational study of fifty consecutive patients without structural heart disease and preserved ejection fraction (LVEF > 50%) presented with high grade atrioventricular block for permanent pacing. Complete 2D and a full volume 3D echocardiography was done before implantation, one-week and 6-months after implantation together with global longitudinal strains analysis (GLS). Patients were followed for 6 months to detect the incidence of PIVD (defined as a reduction in LVEF >10 percentage points but still above 50%) and PICMP (defined as a decrease in LVEF by 10 percentage points from baseline in the absence of other known causes of cardiomyopathy resulting in EF < 50%). PIVD and PICMP predictors and risk factors were analyzed over a 6-month period. Results At six months, 25 (50%) patients developed PIVD; of these, 6 (12%) developed PICMP. Pre-implantation, GLS was significantly lower in the 6 patients who subsequently developed PICMP, compared to those who developed PIVD and the preserved EF group (mean GLS -15.50 vs. -21.0, -20.0 respectively; p = 0.005, 0.033 respectively). At one week, GLS was significantly lower in the 25 patients who subsequently developed PIVD, compared to those who did not (GLS -13.0 vs. -18.0 respectively; p = 0.002). A reduction of baseline GLS by 15% or more at one week was associated with the development of PIVD and PICMP (p = <0.001). A wider native QRS complex was associated with the development of PIVD and PICMP (p = 0.008, 0.018 respectively). The other predictors (Age, Sex, HTN, D.M, Post-pacing QRS width and axis, presence of native BBB, Pacemaker type and lead site) were found non-significant. Conclusion PICMP may be more common than previously reported and it may occur shortly after implantation. This rise in its incidence is due to the application of new sensitive tools like 3D echocardiography and speckle tracking strain. Pre-implantation GLS is a sensitive parameter for the development of PICMP. One-week GLS is an early predictor for the development of PICMP and PIVD before any reduction in EF develops.

4026 Dissecting the role of microenvironment heterogeneity on metastatic tumor cell phenotype at an engineered metastatic niche

OBJECTIVES/GOALS: Breast cancer metastases are stochastic and difficult to detect. Therapy is often ineffective due to phenotypic changes of tumor cells at these sites. We engineered a synthetic metastatic niche to study the role of phenotypic transitions in the microenvironment on tumor cell phenotype. METHODS/STUDY POPULATION: The engineered metastatic niche is composed of a porous polycaprolactone scaffold implanted subcutaneously in Balb/c mice. The mice received an orthotopic inoculation of 4T1 cells (murine triple negative breast cancer) in the fourth right mammary fat pad and the disease was allowed to progress for 7-21 days (pre-metastatic to overt metastatic disease). The scaffolds and lungs (native metastatic site) were explanted and analyzed by single cell RNA-seq via Drop-seq. Cell phenotypes were identified and tracked over time with the Seurat and Monocle3 pipelines. Assessment of the impact of these cell populations on tumor cell phenotype was conducted through Transwell co-cultures. RESULTS/ANTICIPATED RESULTS: Healthy scaffolds are primarily composed of macrophages, dendritic cells, and fibroblasts – consistent with a foreign body response. Despite differences in the lung and scaffold prior to tumor inoculation, both tissues were marked by >5-fold increase in neutrophils/MDSCs. Additionally, 79% of genes at the scaffold that significantly changed over time were also identified in the lung, indicating key similarities in niche maturation. However, many immune cells at the scaffold had distinct phenotypes, with pro-inflammatory/cytotoxic characteristics. These changes clearly impacted tumor cell phenotype, as cells from the scaffold increased tumor cell migration and apoptosis in vitro. DISCUSSION/SIGNIFICANCE OF IMPACT: Early phenotypic changes at the engineered metastatic niche can identify signs of metastasis prior to colonization of tumor cells. Furthermore, dynamics of immune and stromal cells change throughout niche maturation, influencing tumor cell phenotype and may suggest targeted therapies. CONFLICT OF INTEREST DESCRIPTION: Lonnie Shea, Jacqueline Jeruss, and Grace Bushnell are named inventors on patents or patent applications.

Elemental composition of yerba mate (Ilex paraguariensis A.St.-Hil.) under low input systems of southern Brazil

Elemental composition of food can be used to determine nutritional potential as well as guiding legislation for establishing maximum acceptable limits (MAL) of metals in consumption products. This study aimed to determine the elemental background levels of yerba mate (Ilex paraguariensis A.St.-Hil.) under varied geologic formations in southern Brazil. Mature leaves were randomly collected from four wild-grown plants at thirty native sites in three states and analyzed for 32 elements. Since yerba mate is not washed to obtain the final product, leaves were analyzed with and without washing to assess foliar deposition. Concentration values of As, Ag, Be, Cs, Cr, Li, Se, Tl, U, and V were near detection limits, indicating low potential as a source and/or toxicity to the consumer. Washing decreased concentrations of Fe, Ti, As, Mo, Li, V, and Pb, suggesting atmospheric contributions/dust deposition. Concentrations of Mn (very high), Zn (high), and Ni (high) demonstrated that leaves could be an important source of these elements. Soil parent material affected elemental composition with basalt providing higher concentrations of Mn, P, and Co while Rhyodacite provided higher concentrations of K and Na. All samples exhibited Pb values below the MAL of 0.6 mg kg−1, but 23% of washed leaves and 20% of unwashed leaves had Cd concentrations close to or above the MAL value of 0.4 mg kg−1. Study results indicated that Cd MAL values for yerba mate in southern Brazil should be reassessed.