Pulmonary endothelial permeability and tissue fluid balance depend on the viscosity of the perfusion solution

Fluid filtration in the pulmonary microcirculation depends on the hydrostatic and oncotic pressure gradients across the endothelium and the selective permeability of the endothelial barrier. Maintaining normal fluid balance depends both on specific properties of the endothelium and of the perfusing blood. Although some of the essential properties of blood needed to prevent excessive fluid leak have been identified and characterized, our understanding of these remains incomplete. The role of perfusate viscosity in maintaining normal fluid exchange has not previously been examined. We prepared a high-viscosity perfusion solution (HVS) with a relative viscosity of 2.5, i.e., within the range displayed by blood flowing in vessels of different diameters in vivo (1.5–4.0). Perfusion of isolated murine lungs with HVS significantly reduced the rate of edema formation compared with perfusion with a standard solution (SS), which had a lower viscosity similar to plasma (relative viscosity 1.5). HVS did not alter capillary filtration pressure. Increased endothelial shear stress produced by increasing flow rates of SS, to mimic the increased shear stress produced by HVS, did not reduce edema formation. HVS significantly reduced extravasation of Evans bluelabeled albumin compared with SS, indicating that it attenuated endothelial leak. These findings demonstrate for the first time that the viscosity of the solution perfusing the pulmonary microcirculation is an important physiological property contributing to the maintenance of normal fluid exchange. This has significant implications for our understanding of fluid homeostasis in the healthy lung, edema formation in disease, and reconditioning of donor organs for transplantation

Effect of wastewater application on the growth of clumping bamboo species in multispecific plantations

Ce travail a pour objectif l'adaptation en climat tropical d'une technique de phytoépuration utilisant le bambou pour le traitement des eaux usées, déjà développée en climat tempéré. L'étude porte sur la détermination de valeurs de référence pour plusieurs espèces de bambou tropicales (i) des capacités d'absorption d'eau, (ii) de production de biomasse aérienne, et (iii) d'absorption des nutriments. La démarche expérimentale a consisté, dans un premier temps, à déterminer la réponse morphologique de sept espèces de bambous, suite à l'apport excessif de nutriments, comme cela peut se produire lors de l'apport d'eaux usées. Dans un deuxième temps, les capacités d'évapotranspiration de cinq espèces de bambous ont été étudiées en cuves lysimètriques. Enfin, la production de biomasse, ainsi que les prélèvements en azote, phosphore et carbone d'un peuplement multispécifique ont été étudiés en réponse à l'apport de lisier, en conditions réelles d'une station pilote. Ces études ont montré que des apports excessifs en nutriments améliorent la croissance du bambou sans causer de stress détectable. Ils améliorent également la capacité photosynthétique des bambous, ainsi que la production de biomasse, qui est augmentée d'un facteur 2 à 6 selon les espèces, par rapport au traitement témoin. La production de biomasse importante, de l'ordre de 20,7 à 80 tonnes de matière sèche produite par hectare et par an, confère aux espèces étudiées des capacités d'extraction élevées, avec des exportations de 400 à 1600 kg.ha-1 en azote, 30 à 130 kg.ha-1 de phosphore et 18 à 67 t.ha-1 de carbone piégé dans la biomasse en deux ans. Les taux d'évapotranspiration des bambous sont plus élevés que ceux de cultures classiques, avec des valeurs moyennes annuelles comprises entre 4 et 7mm/j et des coefficients culturaux moyens de 2,1 à 3,8 selon les espèces. Cette étude a permis d'identifier plusieurs espèces de bambous intéressantes pour le traitement des eaux usées en climat tropical, notamment les espèces Bambusa oldhamii, Bambusa vulgaris et Gigantochloa wrayii. Dans une optique de phytoépuration ces résultats sont d'autant plus encourageants qu'ils ont été obtenus avec des plants de bambou n'ayant pas encore atteints leur pleine maturité.The aim of this work was to adapt under tropical climate, a wastewater treatment phytotechnology which uses bamboo species, already developed under temperate climate. The objectives of the study were to establish reference values on the water and nutrient uptakes, and on above-ground biomass yields, for different tropical bamboo species. The experimental approach relied first in the quantification of the morphological response of seven bamboo species under high nutrient loads, up to 13.2 t.ha-1.yr-1 of NPK, as it occurs in wastewater treatment system. Second time, the evapotranspiration rates and crop coefficients of five bamboo species were determined using a lysimeter experiment. Finally, the biomass yield and the nitrogen, phosphorus and carbon uptakes were studied for a multi-specific bamboo plantation in response to pig slurry application, at field scale. The results have shown that the high nutrient load (13.2 t.ha-1.yr-1 of NPK) did not cause any detectable stress on the bamboo growth. On the contrary, the photosynthetic activity was improved and the growth rate was increased by 2 to 6 times compared with the control treatment. Depending on bamboo species, the annual biomass yield ranges from 20,7 to 80 t.ha-1.yr-1, and the nutrients storage into the biomass was 400 to 1600 kg.ha-1 for nitrogen, 30 to 130 kg.ha-1 for phosphorus and 18 to 67 t.ha-1 for carbon, in two years of experiment. The yearly average evapotranspiration rates were higher than for typical crops and range from 4 to 7mm.day-1, with average crop coefficients between 2.1 to 3.8, depending on species. Due to their high biomass yield, high nutrient uptakes and high evapotranspiration rates, some bamboo species, i.e. Bambusa oldhamii, Bambusa vulgaris and Gigantochloa wrayii appear as good candidates for wastewater treatment under tropical climate. These results are even more promising since they were obtained for non mature bamboo plants

Effects of High Nutrient Supply on the Growth of Seven Bamboo Species

International audienceOver the last decade, bamboo has emerged as an interesting plant for the treatment of various polluted waters using plant-based wastewater treatment systems. In these systems, nitrogen and phosphorous concentrations in wastewater can exceed plant requirements and potentially limit plant growth. The effects of two nutrient rates on the growth of seven bamboo species were assessed in a one-year experiment: Dendrocalamus strictus, Thyrsostachys siamensis, Bambusa tuldoides, Gigantochloa wrayi, Bambusa oldhamii, Bambusa multiplex and Bambusa vulgaris. Nutrient rates were applied with a 20:20:20 NPK fertilizer as 2.6 and 13.2 t.ha.yr−1NPK to three-year-old bamboo planted in 70 L containers. Morphological characters, photosynthetic responses, and NPK content in bamboo tissues were investigated. Under high-nutrient supply rate, the main trend observed was an increase of culm production but the culms’ diameters were reduced. For the seven species, the aboveground biomass yield tended to increase with high-nutrient rate. Increasing in nutrient rates also improved the photosynthetic activity which is consistent with the increase of nitrogen and phosphorus contents measured in plant tissues. All the bamboo species tested appears suitable for wastewater treatment purposes, but the species Bambusa oldhamii and Gigantochloa wrayi showed the higher biomass yield and nutrient removal

Bamboo Plantations for Phytoremediation of Pig Slurry: Plant Response and Nutrient Uptake

International audienceOn Réunion Island, a French overseas territory located in the western Indian Ocean, increasing pig livestock farming is generating large quantities of slurry. Most of it is spread on a little agricultural land due to the insular context. Considering the limitation of the quantities that can be spread on agricultural areas (European “Nitrate Directive” 91/676/EEC), the use of wastewater treatment systems using phytoremediation principles is an attractive option for the pig slurry treatment. A wastewater treatment system using bamboo groves was assessed for the pig slurry treatment. Three field plots were designed on an agricultural area and planted with 40 bamboo clumps on each plot. A total of 67 m3 of pig slurry was spread on two plots in two forms: raw slurry and centrifuged slurry. The latter plot was watered with tap water. The total amount of nitrogen, phosphorus and potassium was 5.3, 1.4 and 5.5 t·ha−1, respectively, for the raw slurry treatment and 4.2, 0.4 and 5.1 t·ha−1, respectively, for the centrifuged slurry treatment. The response of bamboo species to pig slurry application was determined using morphologic parameters, Chlorophyll a fluorescence measurements and biomass yield. Compared to the control, the biomass increased by 1.8 to 6 times, depending on the species and the form of slurry. Depending on the species, the average biomass ranged from 52 to 135 t.DM.ha−1 in two years of experiment

Microbial biomarkers of tree water status for next‐generation biomonitoring of forest ecosystems

International audienceNext-generation biomonitoring proposes to combine machine-learning algorithms with environmental DNA data to automate the monitoring of the Earth's major ecosystems. In the present study, we searched for molecular biomarkers of tree water status to develop next-generation biomonitoring of forest ecosystems. Because phyllosphere microbial communities respond to both tree physiology and climate change, we investigated whether environmental DNA data from tree phyllosphere could be used as molecular biomarkers of tree water status in forest ecosystems. Using an amplicon sequencing approach, we analysed phyllosphere microbial communities of four tree species (Quercus ilex, Quercus robur, Pinus pinaster and Betula pendula) in a fores

Coupling ecological network analysis with high-throughput sequencing-based surveys: Lessons from the next-generation biomonitoring project

International audienceBiomonitoring ecosystems is necessary in order to evaluate risks and to efficiently manage ecosystems and their associated services. Agrosystems are the target of multiple stressors that can affect many species through effects cascading along food webs. However, classic biomonitoring, focused on species diversity or indicator species, might be a poor predictor of the risk of such whole-ecosystem perturbations. Thanks to high-throughput sequencing methods, however, it might be possible to obtain sufficient information about entire ecological communities to infer the functioning of their associated interaction networks, and thus monitor more closely the risk of the collapse of entire food webs due to external stressors. In the course of the ‘next-generation biomonitoring’ project, we collectively sought to experiment with this idea of inferring ecological networks on the basis of metabarcoding information gathered on different systems. We here give an overview of issues and preliminary results associated with this endeavour and highlight the main difficulties that such next-generation biomonitoring is still facing. Going from sampling protocols up to methods for comparing inferred networks, through biomolecular, bioinformatic, and network inference, we review all steps of the process, with a view towards generality and transferability towards other systems. © 2022 Elsevier Lt

Coupling ecological network analysis with high-throughput sequencing-based surveys: Lessons from the next-generation biomonitoring project

Biomonitoring ecosystems is necessary in order to evaluate risks and to efficiently manage ecosystems and their associated services. Agrosystems are the target of multiple stressors that can affect many species through effects cascading along food webs. However, classic biomonitoring, focused on species diversity or indicator species, might be a poor predictor of the risk of such whole-ecosystem perturbations. Thanks to high-throughput sequencing methods, however, it might be possible to obtain sufficient information about entire ecological communities to infer the functioning of their associated interaction networks, and thus monitor more closely the risk of the collapse of entire food webs due to external stressors.In the course of the ‘next-generation biomonitoring’ project, we collectively sought to experiment with this idea of inferring ecological networks on the basis of metabarcoding information gathered on different systems. We here give an overview of issues and preliminary results associated with this endeavour and highlight the main difficulties that such next-generation biomonitoring is still facing. Going from sampling protocols up to methods for comparing inferred networks, through biomolecular, bioinformatic, and network inference, we review all steps of the process, with a view towards generality and transferability towards other systems.Biosurveillance Next-Gen des changements dans la structure et le fonctionnement des écosystèmesAdaptation et résilience des réseaux écologiques spatialisés face aux changements d'origine humain