Exploring the Diversity and Aromatic Hydrocarbon Degrading Potential of Epiphytic Fungi on Hornbeams from Chronically Polluted Areas

Plants can ‘catch’ and mitigate airborne pollutants and are assisted by fungi inhabiting their leaves. The structure and function of the fungal communities inhabiting the phyllosphere of hornbeam trees growing in two chronically polluted areas, the oilfield of Bóbrka and the city center of Warsaw, were compared to the ones growing in one nature reserve, the Białowieża National Park. Fungi were isolated and characterized both phylogenetically and functionally for their potential role in air pollution mitigation. Both culture-dependent (e.g., enzyme assays and tolerance tests) and culture-independent methods (e.g., ITS and shotgun sequencings) were used. Furthermore, the degradation potential of the fungi was assessed by gas chromatography mass spectrometry (GC-MS). Shotgun sequencing showed that the phyllosphere fungal communities were dominated by fungi belonging to the phylum Ascomycota. Aureobasidium was the only genus detected at the three locations with a relative abundance ≥1.0%. Among the cultivated epiphytic fungi from Bóbrka, Fusarium sporotrichioides AT11, Phoma herbarum AT15, and Lophiostoma sp. AT37 showed in vitro aromatic hydrocarbon degradation potential with laccase activities of 1.24, 3.62, and 7.2 µU L−1, respectively, and peroxidase enzymes with activities of 3.46, 2.28, and 7.49 µU L−1, respectively. Furthermore, Fusarium sporotrichioides AT11 and Phoma herbarum AT15 tolerated exposure to airborne naphthalene and benzene. Lophiostoma sp. AT37 was the most tolerant to exposure to these pollutants, in line with being the best potential aromatic hydrocarbon degrader isolated in this study.Fil: Imperato, Valeria. Hasselt University; BélgicaFil: Portillo Estrada, Miguel. Universiteit Antwerp; BélgicaFil: Saran, Anabel. Gobierno de la Provincia de La Pampa. Ministerio Público. Agencia de Investigación Científica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Thoonen, Anneleen. Hasselt University; BélgicaFil: Kowalkowski, Lukasz. Hasselt University; Bélgica. Warsaw University of Life Sciences; PoloniaFil: Gawronski, Stanislaw W.. Warsaw University of Life Sciences; PoloniaFil: Rineau, Francois. Hasselt University; BélgicaFil: Vangronsveld, Jaco. Hasselt University; Bélgica. Maria Curie-Skłodowska University; PoloniaFil: Thijs, Sofie. Hasselt University; Bélgic

Food web uncertainties influence predictions of climate change effects on soil carbon sequestration in heathlands

Carbon cycling models consider soil carbon sequestration a key process for climate change mitigation. However, these models mostly focus on abiotic soil processes and, despite its recognized critical mechanistic role, do not explicitly include interacting soil organisms. Here, we use a literature study to show that even a relatively simple soil community (heathland soils) contains large uncertainties in temporal and spatial food web structure. Next, we used a Lotka–Volterra-based food web model to demonstrate that, due to these uncertainties, climate change can either increase or decrease soil carbon sequestration to varying extents. Both the strength and direction of changes strongly depend on (1) the main consumer’s (enchytraeid worms) feeding preferences and (2) whether decomposers (fungi) or enchytraeid worms are more sensitive to stress. Hence, even for a soil community with a few dominant functional groups and a simulation model with a few parameters, filling these knowledge gaps is a critical first step towards the explicit integration of soil food web dynamics into carbon cycling models in order to better assess the role soils play in climate change mitigation

Role of phytolith occluded carbon of cereales plants for climate change mitigation

Phytolith-occluded carbon (PhytOC) is highly stable, and constitutes an important source of long-term C storage in agrosystems. This stored carbon is resistant to the processes of oxidation of carbon compounds. In our research phytolith content in barley (Estonia) and oat (Poland) grain and straw was assessed at field trials, with Si as a liquid immune stimulant OPTYSIL and compost fertilisation. We showed that cereals can produce relatively high amounts of phytoliths. PhytOC plays a key role in carbon sequestration, particularly for poor, sandy Polish and Estonian soils. The phytolith content was always higher in straw than in grain regardless of the type of cereals. The phytolith content in oat grains varied from 18.46 to 21.28 mg∙g−1 DM, and in straw 27.89–38.97 mg∙g−1 DM. The phytolith content in barley grain ranged from 17.24 to 19.86 mg∙g−1 DM, and in straw from 22.06 to 49.08 mg∙g−1 DM. Our results suggest that oat ecosystems can absorb from 14.94 to 41.73 kg e-CO2∙ha−1 and barley absorb from 0.32 to 1.60 kg e-CO2∙ha−1. The accumulation rate of PhytOC can be increased 3-fold in Polish conditions through foliar application of silicon, and 5-fold in Estonian conditions. In parallel, the compost fertilisation increased the phytolith content in cereals

Epidemiology of surgery associated acute kidney injury (EPIS-AKI): a prospective international observational multi-center clinical study

Purpose: The incidence, patient features, risk factors and outcomes of surgery-associated postoperative acute kidney injury (PO-AKI) across different countries and health care systems is unclear. Methods: We conducted an international prospective, observational, multi-center study in 30 countries in patients undergoing major surgery (> 2-h duration and postoperative intensive care unit (ICU) or high dependency unit admission). The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay. Results: We studied 10,568 patients and 1945 (18.4%) developed PO-AKI (1236 (63.5%) KDIGO stage 1500 (25.7%) KDIGO stage 2209 (10.7%) KDIGO stage 3). In 33.8% PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU. Patients with PO-AKI had greater ICU (6.3% vs. 0.7%) and hospital (8.6% vs. 1.4%) mortality, and longer ICU (median 2 (Q1-Q3, 1-3) days vs. 3 (Q1-Q3, 1-6) days) and hospital length of stay (median 14 (Q1-Q3, 9-24) days vs. 10 (Q1-Q3, 7-17) days). Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration. Conclusion: In a comprehensive multinational study, approximately one in five patients develop PO-AKI after major surgery. Increasing severity of PO-AKI is associated with a progressive increase in adverse outcomes. Our findings indicate that PO-AKI represents a significant burden for health care worldwide

Effects of Liming on Potential Oxalate Secretion and Iron Chelation of Beech Ectomycorrhizal Root Tips.

Liming is used to counteract forest decline induced by soil acidification. It consists of Ca and Mg input to forest soil and not only restores tree mineral nutrition but also modifies the availability of nutrients in soil. Ectomycorrhizal (ECM) fungi are involved in mineral nutrient uptake by trees and can recover them through dissolution of mineral surface. Oxalate and siderophore secretion are considered as the main agents of mineral weathering by ECMs. Here, we studied the effects of liming on the potential oxalate secretion and iron complexation by individual beech ECM root tips. Results show that freshly excised Lactarius subdulcis root tips from limed plots presented a high potential oxalate exudation of 177 muM tip(-1) h(-1). As this ECM species distribution is very dense, it is likely that, in the field, oxalate concentrations in the vicinity of its clusters could be very high. This points out that not only extraradical mycelium but also ECM root tips of certain species can contribute significantly to mineral weathering. Nonmetric multidimensional scaling (NMDS) separated potential oxalate production by ECM root tips in limed and untreated plots, and this activity was mainly driven by L. subdulcis ECMs, but NMDS on potential activity of iron mobilization by ECM root tips did not show a difference between limed and untreated plots. As the mean oxalate secretion did not significantly correlated with the mean iron mobilization by ECM morphotype, we conclude that iron complexation was due to either other organic acids or to siderophores

Liming in a beech forest results in more mineral elements stored in the mantle of Lactarius subdulcis ectomycorrhizas.

Liming is a forest practice used to counteract forest decline induced by soil acidification. It consists of direct Ca and Mg input in forest soil and restores tree mineral nutrition, but also causes drastic changes in nutrient availability in soil. Ectomycorrhizal (ECM) fungi significantly contribute in nutrient uptake by trees, and can recover them through organic acid secretion or through enzymatic degradation of organic matter. The symbiotic fungi use their extraradical mycelium for nutrient uptake, and then store them into the ECM mantle. In this study we measured how liming influences element contents in the mantle of Lactarius subdulcis ECMs, an abundant and particularly active in oxalate and laccase secretion in beech stands. For this purpose we used SEM observation coupled with energy- (EDX) and wavelength-dispersive-X-ray microanalyses (WDX). Results showed that ECM mantles of this species presented significantly higher Ca, Mg, Mn, K, Si, Al and Fe contents in limed plots. The nutrient amounts of L. subdulcis ECMs were significantly different between individuals for all the elements, showing a differential storage ability between individuals. The storage role of the ECM mantle can be interpreted in two different ways: i) a detoxification role for Al or heavy metals and ii) an increased potential nutrient resource by the fungus, which can benefit the tree