Preferential Mobilization Research Articles

Clonal dynamics after allogeneic haematopoietic cell transplantation.

Allogeneic haematopoietic cell transplantation (HCT) replaces the stem cells responsible for blood production with those from a donor1,2. Here, to quantify dynamics of long-term stem cell engraftment, we sequenced genomes from 2,824 single-cell-derived haematopoietic colonies of ten donor-recipient pairs taken 9-31 years after HLA-matched sibling HCT3. With younger donors (18-47 years at transplant), 5,000-30,000 stem cells had engrafted and were still contributing to haematopoiesis at the time of sampling; estimates were tenfold lower with older donors (50-66 years). Engrafted cells made multilineage contributions to myeloid, B lymphoid and T lymphoid populations, although individual clones often showed biases towards one or other mature cell type. Recipients had lower clonal diversity than matched donors, equivalent to around 10-15 years of additional ageing, arising from up to 25-fold greater expansion of stem cell clones. A transplant-related population bottleneck could not explain these differences; instead, phylogenetic trees evinced two distinct modes of HCT-specific selection. In pruning selection, cell divisions underpinning recipient-enriched clonal expansions had occurred in the donor, preceding transplant-their selective advantage derived from preferential mobilization, collection, survival ex vivo or initial homing. In growth selection, cell divisions underpinning clonal expansion occurred in the recipient's marrow after engraftment, most pronounced in clones with multiple driver mutations. Uprooting stem cells from their native environment and transplanting them to foreign soil exaggerates selective pressures, distorting and accelerating the loss of clonal diversity compared to the unperturbed haematopoiesis of donors.

Hydrogeochemical and rare earth element properties of geothermal waters and the use of abandoned oil wells in Diyarbakır

Türkiye is one of the most tectonically active regions in the world. Diyarbakır, which was chosen as the study area, is located in the south-eastern Anatolian region of Türkiye and also in the south of the Bitlis-Zagros Suture Zone (BZSZ). Some of the geothermal resources in Diyarbakır are actively exploited. The temperature of Çermik geothermal waters was recorded at 40–51 °C by MTA (General Directorate of Mineral Research and Exploration) between 2010 and 2014. However, subsequent measurements conducted following the Kahramanmaraş earthquake (Mw: 7.7 on 6 February 2023) revealed that the surface temperature of geothermal fluids had increased to between 52 and 56 °C. Previous studies have indicated that there are also many abandoned oil wells in the region where the wellhead temperatures are around 107 °C. As a result of hydrogeochemical analyses, deep circulating geothermal waters such as Çermik have Na-HCO3 composition, while shallow circulating and mixed cold surface waters such as Çınar, Bismil and Sur have Na-Ca-Cl-HCO3 composition. According to the chalcedony geothermometer results, the reservoir temperatures in the study area vary between 90 °C and 173 °C. REY (Rare Earth Elements and Yttrium) results show that geothermal fluids in the study area have negative cerium (Ce), europium (Eu) and yttrium (Y) anomalies. The negative Ce anomaly indicates that the colder aquifers are close to oxygen-rich surface waters and thermal fluids interact with Karacadağ volcanic rocks. Eu anomalies in groundwater are controlled by preferential mobilisation of Eu2+ during water-rock interaction compared to Eu3+, and negative Eu anomalies indicate leakage of geothermal fluids from granites. The Y/Ho values of the thermal fluids in the study area are between 30 and 40. This value is due to the active contribution of fluorine during the mobilisation of REY as a fluoride or fluorocarbonate ligand complex, causing Y to behave as a heavy pseudolanthanide. δ18O and δ2H isotope values show that the geothermal waters in the study area are of meteoric origin. The obtained results reveal that Diyarbakir province has a geothermal potential and usage potential can be increased by using the abandoned oil wells.

Mineralogy and rare earth elements spatial distribution in the carboniferous rocks of the eastern El Galala El Bahariya, Egypt

The Carboniferous rocks in the eastern part of El Galala El Bahariya were investigated using integrated field and laboratory techniques to determine their mineralogy, rare earth elements (REEs) distribution, and structural lineament density. The succession is mainly composed of argillaceous and minor arenaceous rocks, exhibiting variations in lithology across the study area. The essential minerals of these rocks are quartz, kaolinite, and illite. The accessory minerals include microcline, gypsum, anhydrite, halite, barite, hematite, pyrite, anatase and gibbsite, in addition to, the radioactive and REEs-bearing minerals such as uranophane, xenotime, monazite, and zircon. These minerals are reported in the rocks of the study area for the first time. The types, forms, habits, and modes of occurrence of the recorded minerals indicate multiple origins: allogenic–authigenic, and primary-secondary. REEs in the rocks exhibit enriched patterns with a negative Eu anomaly, likely due to low plagioclase content or and/or Eu removal by alteration processes. The distribution of REEs is influenced by textural attributes, with finer sediments in the southern part showing higher REEs content, ascribed to the high clay content and presence of gibbsite. The preferential mobility of LREEs is evident, explaining elevated LREEs/HREEs ratios in the rocks. Utilizing remote sensing techniques, lithological units and alteration zones were determined using decorrelation stretch and band ratio methods. The structural features, identified by Laplacian filter and edge enhancement, revealed the presence of NW–SE, N–S, and NE–SW faults that structurally regulate alteration zones and REEs distribution. These alteration zones are associated with clay minerals, REEs concentrations, and high lineament structure density. Spatial distribution maps highlight higher REEs concentrations in the southern part of the study area. These findings were validated using various analytical methods, including mineralogical and geochemical investigations, main component analysis, minimum noise fraction, decorrelation stretch, and spectral reflectance studies. They provide new insights into the REEs potential of the Carboniferous rocks and heighten our understanding of REEs genesis and distribution in the region.

Yeast cell wall extracts from Saccharomyces cerevisiae varying in structure and composition differentially shape the innate immunity and mucosal tissue responses of the intestine of zebrafish (Danio rerio).

With the rising awareness of antimicrobial resistance, the development and use of functional feed additives (FFAs) as an alternative prophylactic approach to improve animal health and performance is increasing. Although the FFAs from yeasts are widely used in animal and human pharma applications already, the success of future candidates resides in linking their structural functional properties to their efficacy in vivo. Herein, this study aimed to characterise the biochemical and molecular properties of four proprietary yeast cell wall extracts from S. cerevisiae in relation to their potential effect on the intestinal immune responses when given orally. Dietary supplementation of the YCW fractions identified that the α-mannan content was a potent driver of mucus cell and intraepithelial lymphocyte hyperplasia within the intestinal mucosal tissue. Furthermore, the differences in α-mannan and β-1,3-glucans chain lengths of each YCW fraction affected their capacity to be recognised by different PRRs. As a result, this affected the downstream signalling and shaping of the innate cytokine milieu to elicit the preferential mobilisation of effector T-helper cell subsets namely Th17, Th1, Tr1 and FoxP3+-Tregs. Together these findings demonstrate the importance of characterising the molecular and biochemical properties of YCW fractions when assessing and concluding their immune potential. Additionally, this study offers novel perspectives in the development specific YCW fractions derived from S. cerievisae for use in precision animal feeds.

Stormwater Best Management Practices: Experimental Evaluation of Chemical Cocktails Mobilized by Freshwater Salinization Syndrome.

Freshwater Salinization Syndrome (FSS) refers to the suite of physical, biological, and chemical impacts of salt ions on the degradation of natural, engineered, and social systems. Impacts of FSS on mobilization of chemical cocktails has been documented in streams and groundwater, but little research has focused on the effects of FSS on stormwater best management practices (BMPs) such as: constructed wetlands, bioswales, ponds, and bioretention. However emerging research suggests that stormwater BMPs may be both sources and sinks of contaminants, shifting seasonally with road salt applications. We conducted lab experiments to investigate this premise; replicate water and soil samples were collected from four distinct stormwater feature types (bioretention, bioswale, constructed wetlands and retention ponds) and were used in salt incubation experiments conducted under six different salinities with three different salts (NaCl, CaCl2, and MgCl2). Increased salt concentrations had profound effects on major and trace element mobilization, with all three salts showing significant positive relationships across nearly all elements analyzed. Across all sites, mean salt retention was 34%, 28%, and 26% for Na+, Mg2+ and Ca2+ respectively, and there were significant differences among stormwater BMPs. Salt type showed preferential mobilization of certain elements. NaCl mobilized Cu, a potent toxicant to aquatic biota, at rates over an order of magnitude greater than both CaCl2 and MgCl2. Stormwater BMP type also had a significant effect on elemental mobilization, with ponds mobilizing significantly more Mn than other sites. However, salt concentration and salt type consistently had significant effects on mean concentrations of elements mobilized across all stormwater BMPs (p<0.05), suggesting that processes such as ion exchange mobilize metals mobilize metals and salt ions regardless of BMP type. Our results suggest that decisions regarding the amounts and types of salts used as deicers can have significant effects on reducing contaminant mobilization to freshwater ecosystems.

Curbing Pandemic Through Evolutionary Algorithm-Based Priority Aware Mobility Scheduling

COVID-19 is a global pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2. While swift vaccine development and distribution have arrested the infection spread rate, it is necessary to design public policies that inform human mobility to curb outbreaks from future strains of the virus. While existing non-pharmaceutical approaches employing network science and machine learning offer promising travel policy solutions, they are guided by epidemiological and economic considerations alone and not human itineraries. We introduce an evolutionary algorithm (EA) based mobility scheduler that incorporates the personalized itineraries of individuals to determine the ideal timing of their mobility. We mathematically analyze the computational efficiency versus the optimality trade-off of the mobility scheduler. Through extensive simulations, we demonstrate that the EA-based mobility scheduler can balance the trade-off between (1) optimality and computational cost and (2) fair and preferential human mobility while reducing contagion under lockdown and no-lockdown as well as even and uneven human mobility traffic scenarios. We show that for two human mobility models, the scheduler exhibits lower infection numbers than a baseline trip-planning approach that directs human traffic along the least congested route to minimize contagion. We discuss that the EA scheduler lends itself to intricate mobility schedules of multiple destination choices with varying priorities and socioeconomic and demographic considerations.

Preferential mobilisation of oxidised iron by slab-derived hydrous silicate melts

Preferential mobilisation of oxidised iron by slab-derived hydrous silicate melts

Trans-cortical vessels in the mouse temporal bulla bone are a means to recruit myeloid cells in chronic otitis media and limit peripheral leukogram changes.

Chronic otitis media, inflammation of the middle ear, is a sequel to acute otitis media in ∼8% of children. Chronic otitis media with effusion is the most common cause of childhood deafness and is characterised by effusion of white blood cells into the auditory bulla cavity. Skull flat bones have trans-cortical vessels which are responsible for the majority of blood flow in and out of the bone. In experimental models of stroke and aseptic meningitis there is preferential recruitment of myeloid cells (neutrophils and monocytes) from the marrow in skull flat bones. We report trans-cortical vessels in the mouse temporal bone connect to the bulla mucosal vasculature and potentially represent a means to recruit myeloid cells directly into the inflamed bulla. The mutant mouse strains Junbo (Mecom Jbo/+ ) and Jeff (Fbxo11 Jf/+ ) develop chronic otitis spontaneously; Mecom Jbo/+ mice have highly cellular neutrophil (90%) rich bulla exudates whereas Fbxo11 Jf/+ mice have low cellularity serous effusions (5% neutrophils) indicating differing demand for neutrophil recruitment. However we found peripheral leukograms of Mecom Jbo/+ and Fbxo11 Jf/+ mice are similar to their respective wild-type littermate controls with healthy bullae and infer preferential mobilization of myeloid cells from temporal bulla bone marrow may mitigate the need for a systemic inflammatory reaction. The cytokines, chemokines and haematopoietic factors found in the inflamed bulla represent candidate signalling molecules for myeloid cell mobilization from temporal bone marrow. The density of white blood cells in the bulla cavity is positively correlated with extent of mucosal thickening in Mecom Jbo/+ , Fbxo11 Jf/+ , and Eda Ta mice and is accompanied by changes in epithelial populations and bone remodelling. In Mecom Jbo/+ mice there was a positive correlation between bulla cavity WBC numbers and total bacterial load. The degree of inflammation varies between contralateral bullae and between mutant mice of different ages suggesting inflammation may wax and wane and may be re-initiated by a new wave of bacterial infection. Clearance of white blood cells and inflammatory stimuli from the bulla cavity is impaired and this may create a pro-inflammatory feedback loop which further exacerbates otitis media and delays its resolution.

The growing field of immunometabolism and exercise: Key findings in the last 5 years.

This perspective review highlights the impact of physical exercise on immunometabolic responses in the past 5 years. Understanding immunometabolism as a part of immunological research is essential. Furthermore, the roles of both acute and chronic effects of physical exercise on health, aging, and chronic diseases in immunometabolic changes should be elaborated. In immune cells, β2 adrenergic signaling stimulates the preferential mobilization of inflammatory phenotypes, such as CD16+ monocytes and CD8+ T cells, into the bloodstream after a physical exercise session. The mobilization of immune cells is closely related to the availability of energetic substrates for the cell and mechanisms associated with the uptake and oxidation of fatty acids and glucose. These cells, especially senescent T cells, are mobilized to the peripheral tissues and undergo apoptotic signaling, stimulating the creation of a "vacant space" where new cells will be matured and replaced in the circulation. This results in the upregulation of the expression and secretion of anti-inflammatory cytokines (IL-10 and IL-1ra), leading to increased regulatory immune cells that provide immunoregulatory properties. Thus, we suggest that a significant nutrient available to the cell will favor oxidative metabolism, augment ATP production, and consequently maintain the immune cells in their quiescent state, as well as promote rapid activation function. Therefore, based on the studies discussed in this perspective review, we highlight the importance of performing moderate-intensity continuous and high-intensity intermittent aerobic exercises, due to a higher magnitude of energetic demand and release of anti-inflammatory cytokines (IL-6 and IL-10).

Acute Aerobic Exercise Preferentially Mobilizes Dominant T-cell Clones To Transiently Lower Receptor Polyclonality In Circulation

Exercise mobilizes and redistributes large numbers of memory T-cells, which may contribute to enhanced immune surveillance in regular exercisers. The diversity of T-cell receptors (TCRs) is vital for the human immune system to recognize a host of foreign antigens, but how exercise affects dynamic changes in antigen specific T-cells at the clonal level is not known. PURPOSE: Determine the effect of acute exercise on T-cell clonality and diversity. METHODS: Healthy volunteers (age 21-41 years) completed an incremental continuous cycling bout consisting of 4x5-minute stages at pre-determined power outputs ranging from 50% to 80%, of VO2peak. DNA was extracted from peripheral blood mononuclear cells (PBMCs) collected at rest, during exercise at 80% VO2peak, and 1 hr post, and underwent high throughput TCR-β chain sequencing via Adaptive Biotechnologies. Data was analyzed utilizing the immunoSEQ® Analyzer online software platform. RESULTS: The top ten ranked productive clones were significantly elevated during exercise (p < 0.005) and were mobilized by a greater magnitude compared to compared to less frequent productive clones. As such, the number of unique productive clones was significantly lower at 80%-intensity exercise compared to rest (p = 0.032) and 1 hr-post (p = 0.046). Additionally, TCR clones found during exercise demonstrate a trended decrease in clonal diversity as indicated by Simpson’s D (p = 0.068) and Shannon’s Entropy (p = 0.088). CONCLUSIONS: Exercise mobilizes the most dominant T-cell clones within the repertoire resulting in a less polyclonal repertoire of T-cells in the circulation. This indicates that exercise preferentially mobilizes T-cell clones with specificity to antigens the host has previously encountered. Subsequent work will determine if exercise drives a preferential mobilization of clones that share TCR motifs and clustered networks associated with cytotoxicity, tumor-antigen specificity, and viral experience.

Grain Inoculated with Different Growth Stages of the Fungus, Aspergillus flavus, Affect the Close-Range Foraging Behavior by a Primary Stored Product Pest, Sitophilus oryzae (Coleoptera: Curculionidae).

Although some research has investigated the interactions among stored product insects and microbes, little research has examined how specific fungal life stages affect volatile emissions in grain and linked it to the behavior of Sitophilus oryzae, the cosmopolitan rice weevil. Thus, our goals were to 1) isolate, culture, and identify two fungal life stages of Aspergillus flavus, 2) characterize the volatile emissions from grain inoculated by each fungal morphotype, and 3) understand how microbially-produced volatile organic compounds (MVOCs) from each fungal morphotype affect foraging, attraction, and preference by S. oryzae. We hypothesized that the headspace blends would be unique among our treatments and that this will lead to preferential mobility by S. oryzae among treatments. Using headspace collection coupled with GC-MS, we found the sexual life stage of A. flavus had the most unique emissions of MVOCs compared to the other semiochemical treatments. This translated to a higher interaction with kernels containing grain with the A. flavus sexual life stage, as well as a higher cumulative time spent in those zones by S. oryzae in a video-tracking assay in comparison to the asexual life stage. While fungal cues were important for foraging at close-range, the release-recapture assay indicated that grain volatiles were more important for attraction at longer distances. There was no significant preference between grain and MVOCs in a four-way olfactometer. Overall, this study enhances our understanding of how fungal cues affect the close and longer range foraging ecology of a primarily stored product insect.

Preferential Mobilization of Colonic Hepatic Flexure Facilitates Pancreaticoduodenectomy Procedures.

Several studies recommend that colonic hepatic flexure (CHF) should be mobilized preliminarily in minimally invasive pancreaticoduodenectomy (PD). However, there are little data to support that preferential mobilization of the CHF can positively affect the perioperative events of PD. We aimed to assess the effect of preferential mobilization of the CHF in PD. A retrospective cohort study of patients who underwent PD was performed between 2016 and 2019. Clinical characteristics, operative data, and postoperative surgical complications were recorded. The study included 668 patients; 486 patients underwent open pancreaticoduodenectomy (OPD) and 182 patients underwent laparoscopic pancreaticoduodenectomy (LPD). Patients were divided into CHF-M (OPD, n=129; LPD, n=95) and conventional (OPD, n=357; LPD, n=87) groups according to preferential CHF mobilization. There were no differences between the groups regarding most demographics. Within patients who underwent OPD, decreased estimated blood loss (EBL) (251.2±146.4 vs. 307.3±173.5 mL, P<0.05) was observed in CHF-M group. Within patients who underwent LPD, operative time (328.7±66.3 vs. 406.5±85.5 min, P<0.001), EBL (166.8±96.4 vs. 271.8±130.7 mL, P<0.001), the incidence of clinically relevant pancreaticfistula (7.4% vs. 23.0%, P<0.05), and length of stay (12.3±5.1 vs. 16.0±7.4 d, P<0.05) were decreased in CHF-M group. Moreover, patients with high body mass index who underwent LPD showed more significant differences in operative time (336.0±67.7 vs. 431.9±79.1, P<0.001) and EBL (179.6±97.8 vs. 278.2±135.6, P<0.001) between groups. We first demonstrated that preferential mobilization of the CHF can facilitate PD. The patients who underwent minimally invasive surgery and the patients with high body mass index may benefit more from this technique.

Geochemical constraints on the middle Triassic Kani Zarrineh karst bauxite deposit, Irano–Himalayan belt, NW Iran: Implications for elemental fractionation and parental affinity

The middle Triassic Kani Zarrineh bauxite deposit, in the Irano–Himalayan belt, located 20 km northwest of Saqqez city in northwestern Iran, occurs in depressions of the early Triassic bedrock carbonates of the Elika Formation. The ores formed during the Carnian Pluvial Event under high atmospheric pCO2 conditions and humid episodes. Powder-XRD analyses revealed that the Kani Zarrineh bauxite is mainly composed of diaspore, hematite, and kaolinite. There is a broad inverse relationship between hematite abundance and diaspore abundance in the profile with a downward increase of hematite and an upward increase of diaspore. Among minor constituents, single crystals rich in high field strength elements, such as florencite, monazite-(Ce), xenotime-(Y), and zircon were detected by SEM-EDS analyses. R-mode factor analysis indicates that most of the variance of the dataset is explained by a factor accounting for the competition between the Al2O3–TiO2–Ga–HFSE pool and the SiO2–Fe2O3–U–first row transition metals pool, and related to the coupled effect of a change of redox conditions and climatic regime. The other two factors are related to the importance of phosphate minerals (e.g., florencite and monazite) in hosting LREE, and to the influence that the chemistry of the soil solutions, especially pH, exerted in promoting the preferential mobility of HREE. Both these factors contribute to explaining LREE/HREE fractionation in the Kani Zarrineh bauxite ores. A negative correlation between the Ce/Ce* and the TOC (r = –0.91) corroborates the fact that bauxitization occurred in an environment characterized by a progressive increase in Eh upward. The coupled Ce/Ce* increase and TOC decrease upward are likely related to soil aeration, a progressive increase in soil temperature, and a reduction in soil moisture. An upward decrease of soil moisture is also consistent with an increase in the abundance of Al hydroxides that require drier conditions than those necessary for the formation of Fe oxyhydroxides. Finally, the evaluation of elemental mobility and results of the R-mode factor analysis indicate that, in addition to Al, high field strength elements Nb and Ta can be used confidently for assessing parental affinity of the Kani Zarrineh bauxite ores. The Al/Ta and Nb/Ta ratios and the Sm/Nd and Eu/Eu* provenance proxies reveal that mafic rocks interbedded in the early Triassic bedrock carbonates of the Elika Formation are likely protoliths of the Kani Zarrineh bauxite ores. This finding is consistent with what is observed for some bauxite deposits from the Mediterranean-type karst bauxite belt, especially from northwestern Iran of different ages that basalt rocks were the parent rock of these deposits.

Origins of Os-isotope and platinum-group element compositions of metasomatized peridotite and cumulate pyroxenite xenoliths from Kharchinsky Volcano, Kamchatka

Platinum-group element (PGE) + Re abundances and Os isotopic compositions were determined for metasomatized peridotite and cumulate pyroxenite xenoliths from Kharchinsky Volcano, Kamchatka. Two peridotites have moderately high PGE concentrations with 2.9–3.3 ppb Os and smoothly variable PGE patterns similar to abyssal peridotites and encompassing primitive and depleted mantle compositions. One of these has unradiogenic Os (187Os/188Os = 0.1148) at the lower limit of compositions observed in abyssal peridotite which results in a time of Re depletion (TRD) model age of ∼1.8 Ga. These contrasts Kharchinsky peridotites that are Pt-Ir enriched with sharply fractionated PGE patterns with Pt/Pd = 132–168 and Ir/Ru ∼ 4.0. This pattern of enrichment in the heavier and more highly siderophile Pt and Ir over the lighter and more siderophile-chalcophile Ru and Pd (Fleet and Stone, 1991; Fleet et al., 1991) is consistent with sulfur depletion under oxidizing metasomatic conditions that leave a residue with PGE host minerals that are dominantly alloys. A single Ru-enriched peridotite with low PGE abundances is interpreted to reflect advanced stages of paragenesis driven by metasomatism and resulting in the loss of all PGE and Re relative to Ru. All Kharchinsky peridotites included in this study have relatively unradiogenic Os (187Os/188Os = 0.1148–0.1314) but some are coupled to PGE and lithophile element characteristics that require oxidizing metasomatic conditions (Ce/Ce*≪1.0) and desulfurization leading to a general loss of PGE and data patterns that are consistent overall with low abundances of relatively radiogenic Os in arc peridotites globally (Brandon et al., 1996; Widom et al., 2003; Saha et al., 2005). Kharchinsky pyroxenites, which are relatively undeformed and only weakly metasomatized, have similarly fractionated PGE patterns with enrichments in Pt (5.7–46 ppb) and Pd (0.5–2.7 ppb) but with Os, Ir, and Ru abundances < 0.23 ppb. The patterns resemble arc basalts and may reflect preferential mobility of Pt, Pd, and Re in slab fluids. High Pt and Pt/Pd up to 33 in the pyroxenites indicate that a Pt-rich alloy with high Pt/Pd is present in the early (olivine-rich) cumulate assemblage. Several Kharchinsky samples (peridotites and pyroxenites) are Pt-enriched with high Pt/Os and Pt/Re > 20 that will produce rapid ingrowth of 186Os relative to 187Os. Deep recycling and storage of such subduction-modified rocks might preclude the need for core-mantle exchange to explain 186Os-enrichments in komatiites and Hawaiian picrites originating in the deep mantle (Brandon et al., 1998; Brandon and Walker, 2005).

The riverine flux of molybdenum and its isotopes to the ocean: Weathering processes and dissolved-particulate partitioning in the Amazon basin

Molybdenum (Mo) abundances and isotopes in marine sedimentary rocks have become important tools for understanding the past redox state of the ocean-atmosphere system. Their use depends critically on the size and isotope composition of the dissolved riverine input to the oceans. Previous studies have demonstrated that rivers are isotopically heavier than the upper continental crust, but the reasons why are debated. The debate is important to the question of how the riverine input might change through Earth history, for example in response to tectonic- and climate-driven changes in weathering regime. Here, we present a comprehensive study of Mo and its isotopes in multiple tributaries of the Amazon Basin, across seasons, with the aim of understanding both the controls on riverine transport of Mo and its isotopes and the input to the oceans.For all Amazonian rivers, the dissolved load dominates over the particulate load for Mo, whether the size of the total suspended load is quantified by in-situ filtration or from approaches using cosmogenic data. This finding is common to other highly soluble elements like strontium (Sr), and is very different from published compilations of global rivers, where particulate/dissolved ratios of Mo and Sr have been reported to be an order of magnitude higher than found here for the Amazon. Mo isotope data for the dissolved phase (<0.45 μm) of Amazon rivers (δ98Mo=+0.52 to +1.46, relative to SRM NIST 3134 = +0.25) show substantially less variation than rivers globally (−0.2 to +2.4‰), but Mo concentrations vary over two orders of magnitude (0.06-6.2 nmol kg−1). There is systematic variability between river types, with black and clear water rivers like the Negro and the Tapajós-Trombetas having much lower concentrations and higher Mo isotope ratios than white water rivers. Low water season (November) concentrations are always greater, and Mo isotope compositions lighter, than high water season (June). A small number of analyses shows that the colloidal phase (<0.45 μm, 1 kDa) represents about 20-30% of the total dissolved load, is broadly similar in isotope composition, and invariant in size between seasons. Thus, the greater dissolved concentration and lighter isotope composition in November must predominantly be driven by changes in the “truly-dissolved” fraction.We find little evidence for lithological or mineralogical controls on the Mo isotope composition of Amazonian rivers. Dissolved Mo concentrations are well-correlated with other highly soluble elements found in major minerals, be they silicates, carbonates or sulphides. Rather, molybdenum isotope variations across tributaries and season are best explained by processes related to the weathering regime, including preferential mobilisation of heavy isotopes due to sequestration of the light isotopes to secondary phases in soils. In more detail, soil pH is suggested to play a secondary, but significant, role. The assessment of the global dataset for Mo in rivers in terms of these processes suggests that there could be significant temporal variability in the riverine source of Mo to the oceans, controlled by tectonics and climate and their impact on weathering regime.

Impact of deforestation on soil iron chemistry and isotope signatures in Amazonia

We examined the consequences of soil erosion processes following deforestation and long-term pasture establishment for soil chemical and physical properties and Fe isotope compositions within two distinct areas in the Eastern and Central parts of Amazonia (near Rio Capim, Para, Brazil and Lake Balbina/Rio Uatuma, Amazonas, Brazil).For each area studied, soils selected under forest cover and pasture or after recent slash-and-burn practices were investigated. In both forest ecosystems studied, pedogenesis along slopes reflects the evolution of lateritic crust bearing soils (Ferralsol) into iron depleted soils after leaching (Acrisol) and redox processes (Gleysol). Measurements performed by plasma source mass spectrometry show a large range of iron isotope signature within the soil profiles studied at the bottom of the slopes (i.e. foot slope and/or valley soils), under both forest and pasture. Iron isotopic signature in foot slope soils under forest cover (δ57FeIRMM-14 ~ +0.2 to +0.6‰) and pasture (δ57FeIRMM-14 ~ +0.3‰) are significantly heavier than both the continental crust baseline and the reference ferralitic soils from the top of the hill (δ57FeIRMM-14 ~ +0.1‰). This enrichment in heavy isotopes is attributed to the preferential mobilisation and loss of light iron during pedogenesis that involves redox processes in areas periodically flooded at the foot slope and valley soils. Under forest, light iron depletion (where ~90% of the iron was leached in the first metre of the soil) has greater influence on the soil isotopes signature, particularly in foot slope sand-rich soils close to the river system with a remaining Fe having δ57Fe IRMM-14 ~ +0.6‰. Under pasture where soils experienced erosion processes, iron depletion in foot slope and riverside soils is less important (where only a little more than half of the iron was leached in the first metre of the soil) and the resulting δ57FeIRMM-14 ~ +0.4‰ suggests an input of light iron isotopes via colluvic material deposition. This difference indicates that geomorphological changes due to erosion processes following deforestation (i.e. colluvic processes) lead to an “isotopic rejuvenation” of the soils in the valley, mostly apparent within the riverside soils.For comparison, we investigated isotopic changes in a recently deforested small watershed, near Lake Balbina, Central Amazonia, focusing on riverside soils. Results confirm that the isotopic rejuvenation effect appears within a few months following the first stage of deforestation as a consequence of erosion processes following slash-and-burn practices. Erosion can remove isotopically lighter (i.e. close to the continental crust value of ~0.1‰ in δ57Fe) iron bearing soil material from the top of the hill. When such colluvial soil material accumulates in the bottom of the hills on soils that were initially depleted in light iron isotopes, again due to podzolisation as described in the previous site, it induces an “isotopic rejuvenation” (tending again towards a lighter, continental crust-like δ57Fe signature) of the foot slope and riverside soils, besides changes in landscape morphology, water drainage and soil functioning (i.e. hydromorphic processes). Hence, this study illustrates that Fe isotopes can be used to identify erosion within a deforestation context through “isotope rejuvenation”, even when soil textures make it challenging to unravel.

Dynamics of circulating lipoproteins and lipids in Brown Skua (Stercorarius antarcticus lonnbergi) during the breeding cycle

In central-place foragers the breeding cycle is often the period with the highest energy cost, where dietary and stored lipids play a key role. Lipids are mobilized through blood lipoproteins providing fuel to tissues. Thus, the use of food and endogenous resources with high-energy fats is important to sustain individuals’ nutritional demands. To evaluate the physiological components associated to energetic demands and their variation regarding life history processes, we analysed the plasma circulating lipoprotein levels, the lipid classes and fatty acid (FA) composition in Brown Skua (Stercorarius antarcticus lonnbergi) in breeding stages with different energy requirements: incubation (In), early rearing (Er) and late rearing (Lr). We expected to find differences according to the energy demands of each stage and the sex. The level of Very Low Density lipoproteins was affected by the sex and the breeding stage, whereas Low Density lipoproteins only by the stage. Total plasma lipid content and circulating lipid classes were invariant among the stages studied; however, differences in total plasma FA and monounsaturated FA (oleic and nervonic) abundances were observed among stages. Besides, a decrease in the n-3:n-6 ratio was observed towards the Lr stage. The differences found in lipoproteins may be linked to changes in the energy demands throughout the breeding period. Moreover, the variation observed in FA abundance and n-3:n-6 ratio may be related to a preferential mobilization of FA from stores as fuel or, possibly, to a differential use of the available food resources.

Assessment of the controls on (234U/238U) activity ratios recorded in detrital lacustrine sediments

Understanding landscape evolution on geological time scales has become increasingly important in the light of recent climate warming and intensified land use. Uranium isotopes ((234U/238U) activity ratios) can be used to reconstruct catchment-wide erosion from fine-grained detrital matter, as the lighter nuclide 234U is lost from grains <63 μm into surrounding pore space in a weathering profile, during transportation, and after final deposition. Thus, (234U/238U) activity ratios are a measure for the time elapsed since comminution of bedrock into detrital sediment. When applied to detrital grains in sedimentary deposits, the comminution age allows derivation of past variations in sediment residence time, i.e. the amount of time for which sediments are stored on hillslopes and transported.Loss of 234U is mainly attributed to recoil of 234Th during α-decay of 238U. However, mobilisation of 234U is also controlled by preferential oxidation and leaching of 234U from detrital grains. Further considerations are required concerning the sediment mineralogy and uranium bound to authigenic or endogenic matter.Here, we extend the discussion about the controls on previously published (234U/238U) activity ratios and uranium concentrations of detrital matter along a 5.43 m-long, Late Glacial to Holocene sedimentary record from Lake Ohrid (North Macedonia, Albania). Lake Ohrid is chosen to study how erosion responds to anthropogenic disturbances and climate variability, which are common through the Late Pleistocene and Holocene in the Mediterranean Region. We compared uranium concentration and isotope data to redox-sensitive, mineralogical and biogeochemical proxies. Mineralogical and biogeochemical data show no control on uranium concentration and (234U/238U) activity ratios. Rock magnetic redox proxies indicate uranium mobilisation from detrital matter in more oxic environments. No correlation between (234U/238U) activity ratios and rock magnetic data is observed, which implies that the redox environment has no control on the isotope signal. Monte Carlo simulations reveal that post-depositional preferential mobilisation of 234U has only negligible impact on the calculated sediment residence times. Our model implies that pre-depositional leaching can results in shorter sediment residence times but low (234U/238U) activity ratios during cold and dry intervals imply that recoil is likely the main processes explaining loss of 234U from the detrital grain. This is explained by the time scales studied herein in (>10,000 years), during which preferential leaching is seen to be not significant.

Nitric oxide and light co-regulate glycine betaine homeostasis in sunflower seedling cotyledons by modulating betaine aldehyde dehydrogenase transcript levels and activity

ABSTRACTGlycine betaine (GB), an osmolyte, is produced in chloroplasts by the action of betaine aldehyde dehydrogenase (BADH) on its precursor betaine aldehyde. The present work highlights the significance of nitric oxide (NO) in GB homeostasis as a long-distance salt (120 mM NaCl) stress-elicited response. In light-grown seedling cotyledons, both the activity and transcript levels of BADH are much higher than in dark-grown seedlings irrespective of salt stress. Significantly high accumulation of GB in dark-grown seedling cotyledons indicates its preferential mobilization from cotyledons to other plant parts in light-grown seedlings. NO donor application (diethylenetriamine) maintains high BADH activity in light, although in dark it is brought down marginally. BADH levels are maintained high in light than in dark in respective treatments. Reversal of the effect of NO donor on age-dependent GB content, BADH activity, and transcript levels by NO scavenger (diethyldithiocarbamate) further demonstrates the impact of NO on GB homeostasis in light- and dark-grown seedlings in an age-dependent manner, major modulation being observed in 4-d-old seedlings. The present work, thus, provides new information on co-regulation of GB homeostasis by NO and light. It also puts forward new information of GB–NO crosstalk in maneuvering salt stress sensing as a long-distance response in seedlings.

Predominance of Cand. Patescibacteria in Groundwater Is Caused by Their Preferential Mobilization From Soils and Flourishing Under Oligotrophic Conditions.

Despite the widely observed predominance of Cand. Patescibacteria in subsurface communities, their input source and ecophysiology are poorly understood. Here we study mechanisms of the formation of a groundwater microbiome and the subsequent differentiation of Cand. Patescibacteria. In the Hainich Critical Zone Exploratory, Germany, we trace the input of microorganisms from forested soils of preferential recharge areas through fractured aquifers along a 5.4 km hillslope well transect. Cand. Patescibacteria were preferentially mobilized from soils and constituted 66% of species-level OTUs shared between seepage and shallow groundwater. These OTUs, mostly related to Cand. Kaiserbacteraceae, Cand. Nomurabacteraceae, and unclassified UBA9983 at the family level, represented a relative abundance of 71.4% of the Cand. Patescibacteria community at the shallowest groundwater well, and still 44.4% at the end of the transect. Several Cand. Patescibacteria subclass-level groups exhibited preferences for different conditions in the two aquifer assemblages investigated: Cand. Kaiserbacteraceae surprisingly showed positive correlations with oxygen concentrations, while Cand. Nomurabacteraceae were negatively correlated. Co-occurrence network analysis revealed a central role of Cand. Patescibacteria in the groundwater microbial communities and pointed to potential associations with specific organisms, including abundant autotrophic taxa involved in nitrogen, sulfur and iron cycling. Strong associations among Cand. Patescibacteria themselves further suggested that for many groups within this phylum, distribution was mainly driven by conditions commonly supporting a fermentative life style without direct dependence on specific hosts. We propose that import from soil, and community differentiation driven by hydrochemical conditions, including the availability of organic resources and potential hosts, determine the success of Cand. Patescibacteria in groundwater environments.