Initial results for the composition of the igneous basement of the Bowers and Shirshov Ridges (Bering Sea, NW Pacific)

The Bowers and Shirshov Ridges (hereafter BR and SR, respectively) are two prominent submarine structures of unknown age and provenance in the Bering Sea. So far only a few geochemical data exist on the composition of basement rocks from the SR (Silantyev et al., 1985) and none for the BR. Age and geochemical data are crucial to evaluate if the ridges represent remnant island arcs (Cooper et al. 1981, Scholl 2007), former pieces of Kamchatka rifted away through seafloor spreading (SR: Baranov et al. 1991) or parts of the Mesozoic Hawaiian hot-spot (Steinberger & Gaina, 2007). Here we report the first geochemical data on the composition of the basement rocks from the BR and SR, recovered during KALMAR R/V SONNE cruise 201 (Legs 1b and 2) in 2009. Fresh to moderately altered volcanic rocks were dredged from the northern slope of the BR, from seamounts on the western extension of the BR and from the western slope of the central part of the SR. We studied the petrography of the samples and carried out geochemical analyses of major and trace elements by XRF and ICPMS at ACME Lab (Vancouver, Canada) and CAU (Kiel). The rocks from the northwestern slope of the BR are clinopyroxene (cpx)-phyric basalts with minor amounts of olivine (ol) and plagioclase (plag) microphenocrysts, as well as hbl-plag-cpx-bearing basaltic andesites and trachyandesites. The rocks are strongly enriched in LREE (LaN/YbN = 3.2 – 8.5, N indicates normalization to primitive mantle), fluid-mobile elements (Ba, U, K) relative to NMORB and exhibit clear negative anomalies of HFSE (Nb, Ta and Ti) in primitive mantle-normalized incompatible element diagrams. The BR rocks also have a moderate adakitic signature, as indicated by elevated SrN/YN ratios (6.9 – 12.9). Hbl-cpx-plag trachybasalts from the SR have similar major and trace element compositions (LaN/YbN = 2.1 – 4.9) to the BR rocks. The other magmatic series from the SR comprises massive trachyandesites, trachytes and dacites with rare phenocrysts of plag and cpx. These rocks also have island-arc type incompatible element patterns and are distinct from other rock types from the BR and SR with less LREE enriched patterns (LaN/YbN ~ 1.8) and a strong negative Eu anomaly (Eu/Eu* = 0.74). Rocks dredged from a seamount on the western extension of the BR have very distinctive petrographic and geochemical characteristics. These are ol-phyric pillow basalts with minor (less than 5%) amounts of plag and cpx. The freshest whole rocks and pillow-rim glasses have relatively smooth patterns of incompatible trace elements, akin to intraplate oceanic basalts and in some characteristic incompatible element ratios (e.g. ThN/BaN = 0.6, SrN/CeN = 1.2, LaN/YbN = 3.3) are similar to Hawaiian hotspot tholeiites. In summary, petrography and preliminary geochemical results indicate an island-arc origin for major parts of the BR and SR. The discovery of intraplate basalts suggests that fragments of the Emperor Seamount Chain could also be preserved in the Bering Sea (Steinberger & Gaina 2007) as seamounts and in the BR and SR basement. Our further studies will be focused on obtaining absolute age data for the studied rocks, which will allow combining the petrologic data with tectonic and geodynamic models for the NW Pacific

Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange

Semi-arid ecosystems contribute about 40% to global net primary production (GPP) even though water is a major factor limiting carbon uptake. Evapotranspiration (ET) accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE) were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated. The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43 and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss) similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E) and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to drought

Linking complement C3 and B cells in nasal polyposis

Nasal polyposis often is characterized by a persistent inflammation of the sinonasal mucosa, disease recurrence after medical or surgical intervention, and asthma comorbidity. Dysregulated complement activation may contribute to immunologic alterations and disease. To date, there is only scattered knowledge on the source and regulation of the central complement factors in the pathogenesis of nasal polyps. Here, we aim to study complement signatures, especially the C3-C3aR axis, and focus on cellular sources and targets in nasal polyps. Expression of complement factors, including C3, C5, and the anaphylatoxin receptors, was analyzed in nasal polyp tissue samples, the corresponding inferior turbinates, and healthy controls using transcriptomic methods and protein measurements. Distinct patterns of complement expression were found in nasal polyps compared to controls, characterized by an increased C3 activation and an increase in C3aR-bearing cells. In contrast, no difference was shown for epithelial-dependent C3 production. Besides low intracellular C3-expression levels for lymphocytes in general, we could identify an enlarged B lymphocyte population in nasal polyps displaying high amounts of intracellular C3. Our data suggest a prominent role for the C3-C3aR-axis in nasal polyps and, for the first time, describe a B cell population containing high levels of intracellular C3, suggesting a new role of B cells in the maintenance of the inflammation by complement

A subset of human plasmacytoid dendritic cells expresses CD8α upon exposure to herpes simplex virus type 1

Classical and plasmacytoid dendritic cells (DC) play important roles in the defense against murine and human infections with herpes simplex virus (HSV). So far, CD8α expression has only been reported for murine DC. CD8α+ DC have prominent cross-presenting activities, which are enhanced by murine CD8α+ PDC. The human orthologue of murine CD8α+ DC, the CD141 (BDCA3)+ DC, mainly cross-present after TLR3 ligation. We report here the serendipitous finding that a subset of human PDC upregulates CD8α upon HSV-1 stimulation, as shown by gene array and flow cytometry analyses. CD8α, not CD8ß, was expressed upon exposure. Markers of activation, migration, and costimulation were upregulated on CD8α-expressing human PDC. In these cells, increased cytokine and chemokine levels were detected that enhance development and function of T, B, and NK cells, and recruit immature DC, monocytes, and Th1 cells, respectively. Altogether, human CD8α+ PDC exhibit a highly activated phenotype and appear to recruit other immune cells to the site of inflammation. Further studies will show whether CD8α-expressing PDC contribute to antigen cross-presentation, which may be important for immune defenses against HSV infections in vitro and in vivo

Gp130-Dependent Release of Acute Phase Proteins Is Linked to the Activation of Innate Immune Signaling Pathways

Background: Elevated levels of acute phase proteins (APP) are often found in patients with cardiovascular diseases. In a previous study, we demonstrated the importance of the IL-6-gp130 axis-as a key regulator of inflammatory acute phase signaling in hepatocytes-for the development of atherosclerosis. Background/Principal Findings: Gp130-dependent gene expression was analyzed in a previously established hepatocytespecific gp130 knockout mouse model. We performed whole transcriptome analysis in isolated hepatocytes to measure tissue specific responses after proinflammatory stimulus with IL-6 across different time points. Our analyses revealed an unexpected small gene cluster that requires IL-6 stimulus for early activation. Several of the genes in this cluster are involved in different cell defense mechanisms. Thus, stressors that trigger both general stress and inflammatory responses lead to activation of a stereotypic innate cellular defense response. Furthermore, we identified a potential biomarker Lipocalin (LCN) 2 for the gp130 dependent early inflammatory response. Conclusions/Significance: Our findings suggest a complex network of tightly linked genes involved in the early activatio

Effects of an extremely dry winter on net ecosystem carbon exchange and tree phenology at cork oak woodland

In seasonally dry climates, such as the Mediterranean, lack of rainfall in the usually wet winter may originate severe droughts which are a main cause of inter-annual variation in carbon sequestration. Leaf phenology variability may alter the seasonal pattern of photosynthetic uptake, which in turn is determined by leaf gas exchange limitations. The current study is based on the monitoring of an extremely dry winter in an evergreen cork oak woodland under the Mediterranean climate of central Portugal. Results are focused on net ecosystem CO2 exchange (NEE), phenology and tree growth measurements during two contrasting years: 2011, a wet year with a typical summer drought pattern and 2012, with an extremely unusual dry winter (only 10mmof total rainfall) that exacerbated the following summer drought effects. Main aims of this study were to assess the effects of an extreme dry winter in (1) annual and seasonal net ecosystem CO2 exchange, and in (2) cork oak phenology. The dry year 2012 was marked by a 45% lower carbon sequestration (−214 vs. −388gCm−2 year−1) and a 63% lower annual tree diameter growth but only a 9% lower leaf area index compared to the wet year 2011. A significant reduction of 15% in yearly carbon sequestration was associated with leaf phenological events of canopy renewal in the early spring. In contrast to male flower production, fruit setting was severely depressed by water stress with a 54% decrease during the dry year. Our results suggest that leaf growth and leaf area maintenance are resilient ecophysiological processes under winter drought and are a priority carbon sink for photoassimilates in contrast to tree diameter growth. Thus, carbon sequestration reductions under low water availabilities in cork oak woodland should be ascribed to stomatal regulation or photosynthetic limitations and to a lesser extent to leaf area reductionsinfo:eu-repo/semantics/publishedVersio

Tracing plant source water dynamics during drought by continuous transpiration measurements : An in-situ stable isotope approach

Publisher Copyright: © 2022 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.The isotopic composition of xylem water (δX) is of considerable interest for plant source water studies. In-situ monitored isotopic composition of transpired water (δT) could provide a nondestructive proxy for δX-values. Using flow-through leaf chambers, we monitored 2-hourly δT-dynamics in two tropical plant species, one canopy-forming tree and one understory herbaceous species. In an enclosed rainforest (Biosphere 2), we observed δT-dynamics in response to an experimental severe drought, followed by a 2H deep-water pulse applied belowground before starting regular rain. We also sampled branches to obtain δX-values from cryogenic vacuum extraction (CVE). Daily flux-weighted δ18OT-values were a good proxy for δ18OX-values under well-watered and drought conditions that matched the rainforest's water source. Transpiration-derived δ18OX-values were mostly lower than CVE-derived values. Transpiration-derived δ2HX-values were relatively high compared to source water and consistently higher than CVE-derived values during drought. Tracing the 2H deep-water pulse in real-time showed distinct water uptake and transport responses: a fast and strong contribution of deep water to canopy tree transpiration contrasting with a slow and limited contribution to understory species transpiration. Thus, the in-situ transpiration method is a promising tool to capture rapid dynamics in plant water uptake and use by both woody and nonwoody species.Peer reviewe

Polygenic risk for schizophrenia and bipolar disorder in relation to cardiovascular biomarkers

Individuals with schizophrenia and bipolar disorder are at an increased risk of cardiovascular disease (CVD), and a range of biomarkers related to CVD risk have been found to be abnormal in these patients. Common genetic factors are a putative underlying mechanism, alongside lifestyle factors and antipsychotic medication. However, the extent to which the altered CVD biomarkers are related to genetic factors involved in schizophrenia and bipolar disorder is unknown. In a sample including 699 patients with schizophrenia, 391 with bipolar disorder, and 822 healthy controls, we evaluated 8 CVD risk biomarkers, including BMI, and fasting plasma levels of CVD biomarkers from a subsample. Polygenic risk scores (PGRS) were obtained from genome-wide associations studies (GWAS) of schizophrenia and bipolar disorder from the Psychiatric Genomics Consortium. The CVD biomarkers were used as outcome variables in linear regression models including schizophrenia and bipolar disorder PGRS as predictors, age, sex, diagnostic category, batch and 10 principal components as covariates, controlling for multiple testing by Bonferroni correction for the number of independent tests. Bipolar disorder PGRS was significantly (p = 0.03) negatively associated with BMI after multiple testing correction, and schizophrenia PGRS was nominally negatively associated with BMI. There were no other significant associations between bipolar or schizophrenia PGRS, and other investigated CVD biomarkers. Despite a range of abnormal CVD risk biomarkers in psychotic disorders, we only found a significant negative association between bipolar disorder PGRS and BMI. This has previously been shown for schizophrenia PGRS and BMI, and warrants further exploration