Net Accumulation Research Articles

Type-4 Phosphodiesterase (PDE4) Blockade Reduces NETosis in Cystic Fibrosis.

Neutrophilic inflammation is a key determinant of cystic fibrosis (CF) lung disease. Neutrophil-derived free DNA, released in the form of extracellular traps (NETs), significantly correlates with impaired lung function in patients with CF, underlying their pathogenetic role in CF lung disease. Thus, specific approaches to control NETosis of neutrophils migrated into the lungs may be clinically relevant in CF. We investigated the efficacy of phosphodiesterase (PDE) type-4 inhibitors, in vitro, on NET release by neutrophils from healthy volunteers and individuals with CF, and in vivo, on NET accumulation and lung inflammation in mice infected with Pseudomonas aeruginosa. PDE4 blockade curbed endotoxin-induced NET production and preserved cellular integrity and apoptosis in neutrophils, from healthy subjects and patients with CF, challenged with endotoxin, in vitro. The pharmacological effects of PDE4 inhibitors were significantly more evident on CF neutrophils. In a mouse model of Pseudomonas aeruginosa chronic infection, aerosol treatment with roflumilast, a selective PDE4 inhibitor, gave a significant reduction in free DNA in the BALF. This was accompanied by reduced citrullination of histone H3 in neutrophils migrated into the airways. Roflumilast-treated mice showed a significant improvement in weight recovery. Our study provides the first evidence that PDE4 blockade controls NETosis in vitro and in vivo, in CF-relevant models. Since selective PDE4 inhibitors have been recently approved for the treatment of COPD and psoriasis, our present results encourage clinical trials to test the efficacy of this class of drugs in CF.

EEG Fingerprint Methodology Application to the Motor Cortices

The controls on the evolution of linear dunefields are poorly understood, despite the potential for reactivation of dunefields, which are currently stabilized by vegetation, under the influence of 21st century climate change. The relative roles of local influences (i.e. boundary conditions) and morphodynamic influences (i.e. emergent properties) remain unclear. Chronostratigraphic and sedimentological analyses were conducted on two pairs of linear dunes exhibiting different spatial patterning in the Strzelecki Desert of central Australia. It was hypothesized that morphodynamic influences, via pattern-coarsening, would mean that dunes from the simpler pattern, defined in terms of the frequency of defects (i.e. junctions and terminations), would be more mature, older landforms. Optically Stimulated Luminescence (OSL) dating of full-depth, regularly-sampled profiles was used to establish accumulation histories for the four dunes, and supported by sedimentological analysis to investigate possible compositional differences and similarities between the dunes. Whilst three of the dunes (the two more simply-patterned dunes, and one of the more complex dunes) have accumulation histories beginning between ~ 100 ka and 150 ka, and document sporadic net accumulation throughout the last interglacial/glacial cycle to the late Holocene, one of the dunes (with relatively complex patterning) reveals that the majority of the dune accumulation (> 7 m) at that site occurred during a relatively short window at ~ 50 ka. There is no clear sedimentological reason for the different behaviour of the younger dune. The data suggest that small-scale and essentially stochastic nature of the aeolian depositional/erosional system can overprint any large-scale morphodynamic controls. The concept of dating landscape change by pattern analysis is thus not supported by this study, and would require very careful interpretation of the scales being considered. This further suggests caution when interpreting dune chronostratigraphies palaeoenvironmentally, as different dunes are able to respond very differently to the same external stimulus (e.g. climate). In the case studied here, a mechanism is proposed to account for the rapid accumulation of the anomalous dune by avulsion of the local aeolian accumulation from one dune ridge to another.

Temporal dynamics of mixed litter humification in an alpine treeline ecotone

Loss of plant diversity affects mountain ecosystem properties and processes, yet few studies have focused on the impact of plant function type deficiency on mixed litter humification. To fill this knowledge gap, we conducted a 1279-day litterbag decomposition experiment with six plant functional types of foliar litter to determine the temporal dynamic characteristics of mixed litter humification in a coniferous forest (CF) and an alpine shrubland (AS). The results indicated that the humus concentrations, the net accumulations and their relative mixed effects (RME) of most types were higher in CF than those in AS at 146 days, and humus net accumulations fell to approximately -80% of the initial level within 1279 days. The RME of the total humus and humic acid concentrations exhibited a general change from synergistic to antagonistic effects over time, but the mixing of single plant functional type impeded the formation of fulvic acid due to consistently exhibited antagonistic effects. Ultimately, correlation analysis indicated that environmental factors (temperature, snow depth and freeze-thaw cycles) significantly hindered litter humification in the early stage, while some initial quality factors drove this process at a longer scale. Among these aspects, the concentrations of zinc, copper and iron, as well as acid-unhydrolyzable residue (AUR):nitrogen and AUR:phosphorous, stimulated humus accumulation, while water-soluble extractables, potassium, magnesium and aluminium hampered it. Deficiencies in a single plant functional type and vegetation type variations affected litter humification at the alpine treeline, which will further affect soil carbon sequestration, which is of great significance for understanding the material circulation of alpine ecosystems.

Abstract P144: Local Signaling And Cardiac Hypertrophy:specificity In The Face Of Pleiotropy

Rationale: Most likely, the overall myocyte cell growth during the pathological state of cardiac hypertrophy is regulated by a local muscle A-kinase anchoring protein β (mAKAPβ) complex. The mAKAPβ may act as a significant coordinator of myocyte hypertrophic signals. It may critically integrate the hypertrophic signals due to β-adrenergic and leukemia inhibitory factor (LIF)/gp-130 receptor stimulation. Observations suggest that mAKAPβ signalosome may act as a gate-keeper for regulating nuclear factor of activated T cells (NFATc) activity and nuclear localization of this complex might be directly linked to the induction of cardiac hypertrophy. The mAKAPβ complex might function through modulating the profiles of a local cyclic adenosine 3’,5’ monophosphate (cAMP) microdomain at perinuclear region in cardiomyocytes. The acute stimulation of cAMP may be beneficial for the heart, whereas chronic stimulation might cause damage. The transition between the chronic and acute function of cAMP is probably modulated by the ability of myocytes to tightly regulate the cAMP levels in local microdomains across the cell. Any dysfunction in this process may lead to net accumulation and a global rise of cAMP levels, leading to deleterious effects on the heart. Objective: cAMP is a single messenger but delivers multiple messages in myocytes. How is this managed? Here, we aim to investigate a key question that how mAKAPβ signalosome might ensure the microdomain specificity despite the pleiotropic nature of the second messenger. Methods and Results: Our results may explain how, in the context of hypertrophy, mAKAPβ complex coordinates the interactions between two coupled cAMP-induced feedback loops and LIF-induced activation of the MAPK pathway. Our results may also explain that mAKAPβ complex functions through anchoring protein kinase A (PKA) and ERK5 in the signalosome thus, modulating the bidirectional regulation of phosphodiesterase and hence the control of localized cAMP metabolism as well as the shape and temporal profile of the second messenger in a specific domain. Conclusion: Here, we propose a mechanistic model which suggests that stress-induced reprofiling of cAMP flux at discrete cellular locations may lead to cardiovascular disease.

Coastal darkening substantially limits the contribution of kelp to coastal carbon cycles.

Macroalgal-dominated habitats are rapidly gaining recognition as important contributors to marine carbon cycles and sequestration. Despite this recognition, relatively little is known about the production and fate of carbon originating from these highly productive ecosystems, or how anthropogenic- and climate-related stressors affect the role of macroalgae in marine carbon cycles. Here, we examine the impact of increasing turbidity on carbon storage, fixation and loss in southern hemisphere kelp forests. We quantified net primary production (NPP) and biomass accumulation (BA), and estimated carbon release via detritus and dissolved organic carbon (DOC) across a large-scale turbidity gradient. We show that increased turbidity, resulting in a 63% reduction in light, can result in a 95% reduction in kelp productivity. When averaged annually, estimates of NPP and BA per plant at high-light sites were nearly six and two times greater than those at low-light sites, respectively. Furthermore, the quantity of carbon fixed annually by kelp forests was up to 4.7 times greater than that stored as average annual standing stock. At low-light sites, the majority of C goes directly into tissue growth and is subsequently eroded. In contrast, excess production at high-light sites accounts for up to 39% of the total carbon fixed and is likely released as DOC. Turbidity is expected to increase in response to climate change and our results suggest this will have significant impacts on the capacity of kelp forests to contribute to carbon sequestration pathways. In addition to demonstrating that turbidity significantly reduces the quantity of carbon fixed by kelp forests, and subsequently released as detritus, our results highlight the negative impacts of turbidity on a large source of previously unaccounted for carbon.

The Multiscale Monitoring of Peatland Ecosystem Carbon Cycling in the Middle Taiga Zone of Western Siberia: The Mukhrino Bog Case Study

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.

Phosphorus concentrations into a subtropical lake strongly influence nitrogen accumulation, nitrogen export, and Chl a concentrations

We measured water quality monthly for 22 years in water entering, within, and exiting a 65 km2 shallow polymictic and eutrophic freshwater lake in the northern Gulf of Mexico. Fertilizer use in the watershed is the dominate source of phosphorous (P) going into the lake and controls the lake’s P concentrations, but nitrogen (N) fertilizer use was not related to total nitrogen concentration in the lake. Half of the particulate P entering the lake is trapped within it and there is a net accumulation of N that appears to be from the stimulation of nitrogen fixation. The lake’s concentration of Chlorophyll a (µg Chl a l−1) and increase in N in the lake was directly related to the concentration of P in water entering the lake. Variations in the Chl a concentration within a freshwater lake downstream are also directly related to the annual use of P fertilizer, but not to N fertilizer use. Reducing agriculture-sourced P runoff will lower (but not eliminate) both the frequency of algal blooms within Lac des Allemands and the amount of N delivered to the estuary.

Novel dual labelled nanoprobes for nanosafety studies: Quantification and imaging experiment of CuO nanoparticles in C. elegans

Metal oxide nanoparticles have been extensively studied for their toxicological impacts. However, accurate tracing/quantification of the nanomaterials and their biological responses are difficult to measure at low concentrations. To overcome the challenge, we developed a dual-labelling technique of CuO nanoparticles with a stable isotope of 65Cu, and with rhodamine dye. In vivo experiments on C. elegans were performed using natural feeding of Rhodamine B isothiocyanate-(3 aminopropyl) triethoxysilane functionalized 65CuO nanoprobes (RBITC-APTES@65CuO) (size = 7.41 ± 1 nm) within the range of Predicted Environmental Concentration (PEC) of CuO nanoparticles in soil and sediments. Fluorescence emission (570 nm) was detected in the lumen of the intestine and the pharynx of C. elegans with no impact of nanoparticle exposure on the brood size and life span of worms. The ingested fluorescent labelled RBITC-APTES@65CuO nanoprobes did not enter the reproductive system and were distributed in the alimentary canal of C. elegans. Strong fluorescent signals from the ingested RBITC-APTES@65CuO nanoprobes were achieved even after 24 h of exposure demonstrating the high stability of these nanoprobes in vivo. The net accumulation measured of 65Cu in C. elegans after background subtraction was 0.001 μg mg−1 (3.52 %), 0.005 μg mg−1 (1.76 %) and 0.024 μg mg−1 (1.69 %) for an exposure concentration of 0.0284 μg mg−1, 0.284 μg mg−1, and 1.42 μg mg−1 of 65Cu, respectively. Using C. elegans as a model organism, we demonstrated that RBITC-APTES tagged 65CuO nanoparticles acted as novel nanoprobes for measuring the uptake, accumulation, and biodistribution through quantification and imaging the nanoprobes at a very low exposure concentration (65CuO concentration: 0.033 μg mg−1).

Assessment of Biomass Storage, Net Accumulation and Carbon Sequestration in Chir-Pine (<i>Pinus roxburghii</i> Sarg.) Dominated Community Forests of Kumaun Himalaya in relation to Climate Change

The present study deals with the vegetation analysis, biomass storage and carbon sequestration at three different aspects of Van Panchayat (Community) forest sites around Nainital district of Kumaun Himalayas. All three aspects, viz; south-east (SE), east (E) and south (S) of Van Panchayat forests are dominated by Pinus roxburghii Sarg. The density of trees across all aspects of community forests varied from 450 to 670 individuals ha -1 . The basal area values reported varied from 31.16 to 56.32 m 2 ha -1 . The species diversity across aspects ranged from 0.440 to 1.389, 1.656 to 2.319 and 1.962 to 3.152 for trees, shrubs and herbs, respectively. Total biomass storage values of trees across all aspects ranged from 155.83 to 333.77 t ha-1. Net biomass accumulation by trees was 10.53 t ha -1 yr -1 on SE aspect (Chir-Pine forest), 8.05 t ha -1 yr -1 on E aspect (Chir Pine forest) and 7.96 t ha -1 yr -1 on S aspect (Chir-Pine forest). Net annual carbon sequestration of trees varied between 3.54 and 4.36 t C ha -1 yr -1 . The density, biomass storage, net annual biomass accumulation as well as carbon sequestration values reported are higher on SE aspect. It can be predicted that South-East aspect (mixed aspect) plays a significant role in forest growth and maturity as compared to East and South (singal) aspects. In general, strong rules and regulations and effective enforcement must have minimized degradation and deforestation of forests in this Van Panchyat. This will certainly help in increasing forest cover and reducing carbon emission which will lead to minimise rise in CO 2 level of the atmosphere.

An insight on the impact of teleost whole genome duplication on the regulation of the molecular networks controlling skeletal muscle growth.

Fish muscle growth is a complex process regulated by multiple pathways, resulting on the net accumulation of proteins and the activation of myogenic progenitor cells. Around 350–320 million years ago, teleost fish went through a specific whole genome duplication (WGD) that expanded the existent gene repertoire. Duplicated genes can be retained by different molecular mechanisms such as subfunctionalization, neofunctionalization or redundancy, each one with different functional implications. While the great majority of ohnolog genes have been identified in the teleost genomes, the effect of gene duplication in the fish physiology is still not well characterized. In the present study we studied the effect of WGD on the transcription of the duplicated components controlling muscle growth. We compared the expression of lineage-specific ohnologs related to myogenesis and protein balance in the fast-skeletal muscle of pacus (Piaractus mesopotamicus—Ostariophysi) and Nile tilapias (Oreochromis niloticus—Acanthopterygii) fasted for 4 days and refed for 3 days. We studied the expression of 20 ohnologs and found that in the great majority of cases, duplicated genes had similar expression profiles in response to fasting and refeeding, indicating that their functions during growth have been conserved during the period after the WGD. Our results suggest that redundancy might play a more important role in the retention of ohnologs of regulatory pathways than initially thought. Also, comparison to non-duplicated orthologs showed that it might not be uncommon for the duplicated genes to gain or loss new regulatory elements simultaneously. Overall, several of duplicated ohnologs have similar transcription profiles in response to pro-growth signals suggesting that evolution tends to conserve ohnolog regulation during muscle development and that in the majority of ohnologs related to muscle growth their functions might be very similar.

Measures to reduce red cell use in patients with sickle cell disease requiring red cell exchange during a blood shortage

AbstractThe COVID-19 pandemic has created major disruptions in health care delivery, including a severe blood shortage. The inventory of Rh and K antigen–negative red cell units recommended for patients with hemoglobinopathies became alarmingly low and continues to be strained. Because patients with sickle cell disease requiring chronic red cell exchange (RCE) incur a large demand for red cell units, we hypothesized that implementation of 2 measures could reduce blood use. First, obtaining the pretransfusion hemoglobin S (HbS) results by procedure start time would facilitate calculation of exact red cell volume needed to achieve the desired post-RCE HbS. Second, as a short-term conservation method, we identified patients for whom increasing the targeted end procedure hematocrit up to 5 percentage points higher than the pretransfusion level (no higher than 36%) was not medically contraindicated. The goal was to enhance suppression of endogenous erythropoiesis and thereby reduce the red cell unit number needed to maintain the same target HbS%. These 2 measures resulted in an 18% reduction of red cell units transfused to 50 patients undergoing chronic RCE during the first 6 months of the COVID-19 pandemic. Despite reduction of blood use, pretransfusion HbS% target goals were maintained and net iron accumulation was low. Both strategies can help alleviate a shortage of Rh and K antigen–negative red cells, and, more generally, transfusing red cell units based on precise red cell volume required can optimize patient care and judicious use of blood resources.

Biodynamics and adverse effects of CuO nanoparticles and CuCl2 in the oligochaete T. tubifex: Cu form influence biodynamics in water, but not sediment

The use of copper oxide (CuO) NPs results in the release of these particles into the aquatic environment. Here, the particles settle out and accumulate in the sediment. However, little is known about the biodynamics of sediment-associated NPs in benthic organisms. We compared the toxicity and biodynamics of CuO NPs (7 nm) and dissolved Cu (CuCl2) in the sediment-dwelling oligochaete, Tubifex tubifex, to gain insights into the relative importance of metal form (CuCl2 vs CuO NPs) and exposure route (water vs sediment). Isotopically enriched 65Cu was used as a tracer to distinguish background from newly accumulated 65Cu in worms. For each exposure route, we conducted three experiments: one uptake, one elimination, and one longer-term net accumulation experiment to parameterize uptake and elimination of 65CuCl2 and 65CuO NPs in T. tubifex. 65Cu accumulation was detected for both 65CuCl2 and 65CuO NPs regardless of whether T. tubifex were exposed in sediment- or water-only setups. Water exposures to 65CuCl2 resulted in tail trauma whereas limited effects were seen for sediment exposures or exposures to 65CuO NPs via either exposure route. Uptake rate constants and accumulation of 65Cu in T. tubifex were higher following 65CuCl2 exposure than 65CuO NPs, in water, but not in sediment. Thus, the relative importance of exposure route and Cu form for uptake dynamics is not straightforward suggesting that findings on bioaccumulation and toxicity in water exposures cannot be directly extrapolated to sediment.

Regulation of perineuronal nets in the adult cortex by the activity of the cortical network.

Perineuronal net (PNN) accumulation around parvalbumin-expressing (PV) inhibitory interneurons marks the closure of critical periods of high plasticity, whereas PNN removal reinstates juvenile plasticity in the adult cortex. Using targeted chemogenetic in vivo approaches in the adult mouse visual cortex, we found that transient inhibition of PV interneurons, through metabotropic or ionotropic chemogenetic tools, induced PNN regression. Electroencephalographic recordings indicated that inhibition of PV interneurons did not elicit unbalanced network excitation. Likewise, inhibition of local excitatory neurons also induced PNN regression, whereas chemogenetic excitation of either PV or excitatory neurons did not reduce the PNN. We also observed that chemogenetically inhibited PV interneurons exhibited reduced PNN compared to their untransduced neighbors, and confirmed that single PV interneurons express multiple genes enabling individual regulation of their own PNN density. Our results indicate that PNN density is regulated in the adult cortex by local changes of network activity that can be triggered by modulation of PV interneurons. PNN regulation may provide adult cortical circuits with an activity-dependent mechanism to control their local remodeling.SIGNIFICANCE STATEMENTThe perineuronal net is an extracellular matrix, which accumulates around individual parvalbumin-expressing inhibitory neurons during postnatal development, and is seen as a barrier that prevents plasticity of neuronal circuits in the adult cerebral cortex. We found that transiently inhibiting parvalbumin-expressing or excitatory cortical neurons triggers a local decrease of perineuronal net density. Our results indicate that perineuronal nets are regulated in the adult cortex depending on the activity of local microcircuits. These findings uncover an activity-dependent mechanism by which adult cortical circuits may locally control their plasticity.

Copper Content and Export in European Vineyard Soils Influenced by Climate and Soil Properties

Copper-based fungicides (Cuf) are used in European (EU) vineyards to prevent fungal diseases. Soil physicochemical properties locally govern the variation of the total copper content (Cut) in EU vineyards. However, variables controlling Cut distribution at a larger scale are poorly known. Here, machine learning techniques were used to identify governing variables and to predict the Cut distribution in EU vineyards. Precipitation, aridity and soil organic carbon are key variables explaining together 45% of Cut distribution across EU vineyards. This underlines the effect of both climate and soil properties on Cut distribution. The average net export of Cu at the EU scale is 0.29 kg Cu ha-1, which is 2 orders of magnitude less than the net accumulation of Cu (24.8 kg Cu ha-1). Four scenarios of Cuf application were compared. The current EU regulation with a maximum of 4 kg Cu ha-1 year-1 may increase by 2% of the EU vineyard area, exceeding the predicted no-effect concentration (PNEC) in soil in the next 100 years. Overall, our results highlight the vineyard areas requiring specific remediation measures and strategies of Cuf use to manage a trade-off between pest control and soil and water contamination.

Effects of Amendments on Physicochemical Properties and Respiration Rate of Soil from the Arid Region of Northwest China

In arid regions, decreased soil fertility has adversely affected agricultural sustainability. The effects of different amendments in alleviating these issues and increasing soil fertility remain unclear. Herein, a two-year field experiment was conducted to evaluate the properties of grey desert soil and soil respiration (SR) dynamics under six different treatment groups: biochar (BC), leonardite (LD), anionic polyacrylamide (PAM−), cationic polyacrylamide (PAM+) powder, anionic polyacrylamide solution in water (PAM−W), and control (CK). We observed that the BC and LD amendments significantly altered soil pH, organic matter, available nitrogen, available phosphorus, cation exchange capacity, and SR. PAM amendment increased the SR as compared to the control, except in autumn, but PAM did not affect the soil properties. SR under different amendments showed strong seasonal patterns, the highest and lowest SR rates were observed in June and January, respectively. Amendments and seasonal dynamics significantly affected SR, but no interaction was observed between these factors. Temporal variation of SR was substantially influenced by soil temperature at 15 cm of soil depth. Temperature sensitivity of SR (Q10) increased with soil depth and decreased with amendment addition. SR was significantly affected by soil temperature, moisture, air temperature, and their interactions. The outcomes of this study suggested that the BC and LD amendments improved soil fertility and negated the net carbon accumulation by increasing the SR and Q10 in arid agriculture soil.

Quantifying the effects of multiple land management practices, land cover change, and wildfire on the California landscape carbon budget with an empirical model.

The effectiveness of land-based climate mitigation strategies is generally estimated on a case-by-case basis without considering interactions with other strategies or influencing factors. Here we evaluate a new, comprehensive approach that incorporates interactions among multiple management strategies, land use/cover change, wildfire, and climate, although the potential effects of climate change are not evaluated in this study. The California natural and working lands carbon and greenhouse gas model (CALAND) indicates that summing individual practice estimates of greenhouse gas impacts may underestimate emission reduction benefits in comparison with an integrated estimate. Annual per-area estimates of the potential impact of specific management practices on landscape emissions can vary based on the estimation period, which can be problematic for extrapolating such estimates over space and time. Furthermore, the actual area of implementation is a primary factor in determining potential impacts of management on landscape emissions. Nonetheless, less intensive forest management, avoided conversion to urban land, and urban forest expansion generally create the largest annual per-area reductions, while meadow restoration and forest fuel reduction and harvest practices generally create the largest increases with respect to no management. CALAND also shows that data uncertainty is too high to determine whether California land is a source or a sink of carbon emissions, but that estimating effects of management with respect to a baseline provides valid results. Important sources of this uncertainty are initial carbon density, net ecosystem carbon accumulation rates, and land use/cover change data. The appropriate choice of baseline is critical for generating valid results.

Long-term partial replacement of mineral fertilizer with in situ crop residues ensures continued rice yields and soil fertility: A case study of a 27-year field experiment in subtropical China

High yields and environment-related issues because of over-fertilization in rice (Oryza sativa L.) production is a major concern in China. Partial replacement of mineral fertilizer (MF) with organic matter is considered a win–win approach for resource-saving and environmentally friendly rice production. Here, we examined the effects of reduced MF and in situ crop residue on the rice yield and soil fertility in the long term. A 27-year field experiment (a randomized block design with three replicates) in subtropical China was conducted to test the feasibility of the substitution in a double rice paddy ecosystem. The treatments were CT (no fertilizer application considered as control), NPK (mineral fertilizer N, P, and K), and RFC (reduced MF and in situ crop residue to supplement the reduced NPK dose). The crop residue included half of the rice straw and green manure contents, which were retained in situ in the RFC treatment. The RFC maintained the same rice yield and soil fertility levels as NPK. In general, soil organic carbon (SOC) and total nitrogen (TN) content in RFC increased by 10.3% –20.8%, and 7.5% –28.0%, respectively, than that in NPK from the 5th to the 25th years. There was no significant difference in the content and net accumulation of SOC, TN, and TP and soil available nutrients between the RFC and NPK treatments after 25 years. The average annual yields were 9690 and 9872 kg ha−1 for the NPK and RFC treatments, respectively. There was no difference in the yield of the first, second, and annual rice crops between RFC and NPK in most years (six of the fifty-four seasons showed a significant difference). RFC increased the partial factor productivity (PFP), agronomic efficiency (AE) of MF, and yield stability (CV) (p < 0.05). Positive nutrient balance and a reduced loss of nutrients are evident reasons for achieving better indicators (PFP, AE, and CV) for nutrient compensation and organic nutrient utilization in the RFC treatment. The partial replacement of MF with in situ crop residue retention, is a simple and efficient way to maintain the soil fertility and rice yield as NPK in southern China.

Snow Depth and Air Temperature Seasonality on Sea Ice Derived From Snow Buoy Measurements

Snow depth on sea ice is an essential state variable of the polar climate system and yet one of the least known and most difficult to characterize parameters of the Arctic and Antarctic sea ice systems. Here, we present a new type of autonomous platform to measure snow depth, air temperature, and barometric pressure on drifting Arctic and Antarctic sea ice. “Snow Buoys” are designed to withstand the harshest environmental conditions and to deliver high and consistent data quality with minimal impact on the surface. Our current dataset consists of 79 time series (47 Arctic, 32 Antarctic) since 2013, many of which cover entire seasonal cycles and with individual observation periods of up to 3 years. In addition to a detailed introduction of the platform itself, we describe the processing of the publicly available (near real time) data and discuss limitations. First scientific results reveal characteristic regional differences in the annual cycle of snow depth: in the Weddell Sea, annual net snow accumulation ranged from 0.2 to 0.9 m (mean 0.34 m) with some regions accumulating snow in all months. On Arctic sea ice, the seasonal cycle was more pronounced, showing accumulation from synoptic events mostly between August and April and maxima in autumn. Strongest ablation was observed in June and July, and consistently the entire snow cover melted during summer. Arctic air temperature measurements revealed several above-freezing temperature events in winter that likely impacted snow stratigraphy and thus preconditioned the subsequent spring snow cover. The ongoing Snow Buoy program will be the basis of many future studies and is expected to significantly advance our understanding of snow on sea ice, also providing invaluable in situ validation data for numerical simulations and remote sensing techniques.

The benzoate plant metabolite ethyl gallate prevents cellular- and vascular-lipid accumulation in experimental models of atherosclerosis

Ethyl gallate (EG) is a well-known constituent of medicinal plants, but its effects on atherosclerosis development are not clear. In the present study, the anti-atherosclerosis effects of EG and the underlying mechanisms were explored using macrophage cultures, zebrafish and apolipoprotein (apo) E deficient mice. Treatment of macrophages with EG (20 μM) enhanced cellular cholesterol efflux to HDL, and reduced net lipid accumulation in response to oxidized LDL. Secretion of monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) from activated macrophages was also blunted by EG. Fluorescence imaging techniques revealed EG feeding of zebrafish reduced vascular lipid accumulation and inflammatory responses in vivo. Similar results were obtained in apoE-/- mice 6.5 months of age, where plaque lesions and monocyte infiltration into the artery wall were reduced by 70% and 42%, respectively, after just 6 weeks of injections with EG (20 mg/kg). HDL-cholesterol increased 2-fold, serum cholesterol efflux capacity increased by ∼30%, and the levels of MCP-1 and IL-6 were reduced with EG treatment of mice. These results suggest EG impedes early atherosclerosis development by reducing the lipid and macrophage-content of plaque. Underlying mechanisms appeared to involve HDL cholesterol efflux mechanisms and suppression of pro-inflammatory cytokine secretion.

Effects of supplementary concentrates and voluntary forage intake on grazing cattle in pastures of Cynodon plectostachyus in a semi-tropical region of Mexico

The objective of the present study was to evaluate the effects of different levels of concentrate on the productive response of grazing dairy cattle and to determine voluntary forage intake. The experiment was carried out in a 4×4 Latin square design repeated three times, in which different inclusion levels of experimental concentrate were evaluated (EC) vs commercial concentrate (CC). The treatments were as follows: EC1= 7.12 kg DM of EC + grazing, EC2=6.23 kg DM of EC+ grazing, EC3=5.34 kg DM of EC+ grazing, CC=7.12 DM kg of a commonly used commercial concentrate (CC), and free-access grazing. The voluntary intake was determinate throw n-alkanes technique. The variables evaluated in cattle were milk output, live weight, and body condition; milk samples were also taken to determine protein and fat contents. Net herbage accumulation (NHA), forage height, neutral detergent fiber (NDF), acid detergent fiber (ADF), digestibility of organic matter (DIVMO), and metabolizable energy (ME) of pasture grasses were evaluated in addition to voluntary intake and production costs. Significant differences in crude protein content were found between the evaluation periods but were not found for NDF, ADF, DIVMO, NHA, and ME. Significant differences were not found in voluntary intake but were present in total intake. The evaluated treatments did not differ with respect to animal response. Finally, significant differences were found in milk output. Greater milk production was obtained in treatments 1 and 2 (14.92 and 14.50 kg/day/animal, respectively.