Opposing Effects of the Angiopoietins on the Thrombin-Induced Permeability of Human Pulmonary Microvascular Endothelial Cells

BACKGROUND: Angiopoietin-2 (Ang-2) is associated with lung injury in ALI/ARDS. As endothelial activation by thrombin plays a role in the permeability of acute lung injury and Ang-2 may modulate the kinetics of thrombin-induced permeability by impairing the organization of vascular endothelial (VE-)cadherin, and affecting small Rho GTPases in human pulmonary microvascular endothelial cells (HPMVECs), we hypothesized that Ang-2 acts as a sensitizer of thrombin-induced hyperpermeability of HPMVECs, opposed by Ang-1. METHODOLOGY/PRINCIPAL FINDINGS: Permeability was assessed by measuring macromolecule passage and transendothelial electrical resistance (TEER). Angiopoietins did not affect basal permeability. Nevertheless, they had opposing effects on the thrombin-induced permeability, in particular in the initial phase. Ang-2 enhanced the initial permeability increase (passage, P = 0.010; TEER, P = 0.021) in parallel with impairment of VE-cadherin organization without affecting VE-cadherin Tyr685 phosphorylation or increasing RhoA activity. Ang-2 also increased intercellular gap formation. Ang-1 preincubation increased Rac1 activity, enforced the VE-cadherin organization, reduced the initial thrombin-induced permeability (TEER, P = 0.027), while Rac1 activity simultaneously normalized, and reduced RhoA activity at 15 min thrombin exposure (P = 0.039), but not at earlier time points. The simultaneous presence of Ang-2 largely prevented the effect of Ang-1 on TEER and macromolecule passage. CONCLUSIONS/SIGNIFICANCE: Ang-1 attenuated thrombin-induced permeability, which involved initial Rac1 activation-enforced cell-cell junctions, and later RhoA inhibition. In addition to antagonizing Ang-1, Ang-2 had also a direct effect itself. Ang-2 sensitized the initial thrombin-induced permeability accompanied by destabilization of VE-cadherin junctions and increased gap formation, in the absence of increased RhoA activity

APHANOMYCES EUTEICHES, THE OOMYCETE RESPONSIBLE FOR PEAS’ ROOT ROT - CURRENT VIEWS ON THE METHODS FOR INHIBITING ITS PATHOGENICITY

Root rot is considered as one of the diseases that cause serious obstacles to the development of the agricultural sector. The oomycetes group contain the most destructive and causal agents of this disease, in particular Aphanomyces euteiches, the causal agent of root rot in leguminous plants, which is currently a huge constraint for legumes culture in many regions where it is widely practiced. Therefore, it is clear that improving legumes culture is linked to a good knowledge of the disease and its causal agent. The aim of this study is to know more about the pathogen and to look for a good and sustainable control. Aphanomyces euteiches and its severity are influenced by environmental conditions, especially soil conditions. Control of the A. euteiches is very complicated considering the long persistence of zoospores and the structural difference as compared with fungi. However, partial resistance of pea lines and biological control seem to be the best solutions to adopt. Root rot is considered as one of the diseases that cause serious obstacles to the development of the agricultural sector. The oomycetes group contain the most destructive and causal agents of this disease, in particular Aphanomyces euteiches, the causal agent of root rot in leguminous plants, which is currently a huge constraint for legumes culture in many regions where it is widely practiced. Therefore, it is clear that improving legumes culture is linked to a good knowledge of the disease and its causal agent. The aim of this study is to know more about the pathogen and to look for a good and sustainable control. Aphanomyces euteiches and its severity are influenced by environmental conditions, especially soil conditions. Control of the A. euteiches is very complicated considering the long persistence of zoospores and the structural difference as compared with fungi. However, partial resistance of pea lines and biological control seem to be the best solutions to adopt

Structural Characterisation Of A Sol-Gel Copolymer Synthesised From Aliphatic And Aromatic Alkoxysilanes Using 29Si-NMR Spectroscopy

A hybrid organic-inorganic material was prepared from the hydrolytic co-condensation of 3- trimethoxysilylpropylmethacrylate (MAPTMS) and diphenyldiethoxysilane (DPHDES). The synthesis was performed in three steps: (1) MAPTMS pre-hydrolysis, (2) addition of DPHDES, and (3) further hydrolysis of the obtained mixture. 29 Si nuclear magnetic resonance spectroscopy was used to characterise the structural evolution of the mineral network during the synthesis. It revealed the catalytic effect of DPHDES on the condensation reaction of silanol groups, initially observed for pre-hydrolysed MAPTMS. In addition, it was clearly demonstrated that the formation of the highest condensed species of the aromatic oligomers (D2 species) occurred only in the presence of aliphatic oligomers, which decrease the sterical hindrance about the silicon nuclei