Search

Many bacterial pathogens can cause septicemia and spread from the bloodstream into internal organs. During leptospirosis, individuals are infected by contact with Leptospira-containing animal urine-contaminated water. The spirochetes invade internal organs after septicemia to cause disease aggravation, but the mechanism of leptospiral excretion and spreading remains unknown. Here, we demonstrated that Leptospira interrogans entered human/mouse endothelial and epithelial cells and fibroblasts by caveolae/integrin-β1-PI3K/FAK-mediated microfilament-dependent endocytosis to form Leptospira (Lep)-vesicles that did not fuse with lysosomes. Lep-vesicles recruited Rab5/Rab11 and Sec/Exo-SNARE proteins in endocytic recycling and vesicular transport systems for intracellular transport and release by SNARE-complex/FAK-mediated microfilament/microtubule-dependent exocytosis. Both intracellular leptospires and infected cells maintained their viability. Leptospiral propagation was only observed in mouse fibroblasts. Our study revealed that L. interrogans utilizes endocytic recycling and vesicular transport systems for transcytosis across endothelial or epithelial barrier in blood vessels or renal tubules, which contributes to spreading in vivo and transmission of leptospirosis.

Leptospira interrogans is the major causative agent of leptospirosis, an emerging, globally spreading zoonotic infectious disease. The pathogen induces macrophage apoptosis, but the molecular basis and mechanism remain unknown. In the present study, we found that L. interrogans caused apoptosis of phagocytosis-inhibited macrophages, and the product of the L. interrogans LB047 gene (Lep-OMP047) was the unique protein captured by mouse and human Fas proteins. The recombinant expressed Lep-OMP047 (rLep-OMP047) strongly bound mouse and human Fas proteins with equilibrium association constant (KD) values of 5.20 × 10-6 to 2.84 × 10-9 M according to surface plasmon resonance measurement and isothermal titration calorimetry. Flow-cytometric examination showed that 5 μg rLep-OMP047 or 1 μg lipopolysaccharide of L. interrogans (Lep-LPS) caused 43.70% or 21.90% early apoptosis in mouse J774A.1 macrophages and 28.41% or 15.80% for PMA-differentiated human THP-1 macrophages, respectively, but the apoptosis was blocked by Fas-antagonizing IgGs, Fas siRNAs, and caspase-8/-3 inhibitors. Moreover, Lep-OMP047 was significantly upregulated during infection of macrophages. Lep-LPS promoted the expression and cytomembrane translocation of Fas and FasL in macrophages. The JNK and p38 MAPK but not ERK signaling pathways, as well as the transcription factors c-Jun and ATF2 but not CHOP, mediated Lep-LPS-induced Fas/FasL expression and translocation. TLR2 but not TLR4 mediated Lep-LPS-induced JNK/p38 MAPK activation. Therefore, we demonstrated that a novel Fas-binding OMP and LPS of L. interrogans induce macrophage apoptosis through the Fas/FasL-caspase-8/-3 pathway.

BackgroudLeptospira interrogans is the major causative agent of leptospirosis, a worldwide zoonotic disease. Hemorrhage is a typical pathological feature of leptospirosis. Binding of von Willebrand factor (vWF) to platelet glycoprotein-Ibα (GPIbα) is a crucial step in initiation of platelet aggregation. The products of L. interrogans vwa-I and vwa-II genes contain vWF-A domains, but their ability to induce hemorrhage has not been determined.MethodsHuman (Hu)-platelet- and Hu-GPIbα-binding abilities of the recombinant proteins expressed by L. interrogans strain Lai vwa-I and vwa-II genes (rLep-vWA-I and rLep-vWA-II) were detected by flowcytometry, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Hu-platelet aggregation and its signaling kinases and active components were detected by lumiaggregometry, Western analysis, spectrophotometry and confocal microscopy. Hu-GPIbα-binding sites in rLep-vWA-I and rLep-vWA-II were identified by SPR/ITC measurements.FindingsBoth rLep-vWA-I and rLep-vWA-II were able to bind to Hu-platelets and inhibit rHu-vWF/ristocetin-induced Hu-platelet aggregation, but Hu-GPIbα-IgG, rLep-vWA-I-IgG and rLep-vWA-II-IgG blocked this binding or inhibition. SPR and ITC revealed a tight interaction between Hu-GPIbα and rLep-vWA-I/rLep-vWA-II with KD values of 3.87 × 10-7-8.65 × 10-8 M. Hu-GPIbα-binding of rL-vWA-I/rL-vWA-II neither activated the PI3K/AKT-ERK and PLC/PKC kinases nor affected the NO, cGMP, ADP, Ca2+ and TXA2 levels in Hu-platelets. G13/R36/G47 in Lep-vWA-I and G76/Q126 in Lep-vWA-II were confirmed as the Hu-GPIbα-binding sites. Injection of rLep-vWA-I or rLep-vWA-II in mice resulted in diffuse pulmonary and focal renal hemorrhage but this hemorrhage was blocked by rLep-vWA-I-IgG or rLep-vWA-II-IgG.InterpretationThe products of L. interrogans vwa-I and vwa-II genes induce hemorrhage by competitive inhibition of vWF-mediated Hu-platelet aggregation.

Leptospira interrogans is the major causative agent of leptospirosis, an emerging, globally spreading zoonotic infectious disease. The pathogen induces macrophage apoptosis, but the molecular basis and mechanism remain unknown. In the present study, we found that L. interrogans caused apoptosis of phagocytosis-inhibited macrophages, and the product of the L. interrogans LB047 gene (Lep-OMP047) was the unique protein captured by mouse and human Fas proteins. The recombinant expressed Lep-OMP047 (rLep-OMP047) strongly bound mouse and human Fas proteins with equilibrium association constant (KD) values of 5.20 × 10-6 to 2.84 × 10-9 M according to surface plasmon resonance measurement and isothermal titration calorimetry. Flow-cytometric examination showed that 5 μg rLep-OMP047 or 1 μg lipopolysaccharide of L. interrogans (Lep-LPS) caused 43.70% or 21.90% early apoptosis in mouse J774A.1 macrophages and 28.41% or 15.80% for PMA-differentiated human THP-1 macrophages, respectively, but the apoptosis was blocked by Fas-antagonizing IgGs, Fas siRNAs, and caspase-8/-3 inhibitors. Moreover, Lep-OMP047 was significantly upregulated during infection of macrophages. Lep-LPS promoted the expression and cytomembrane translocation of Fas and FasL in macrophages. The JNK and p38 MAPK but not ERK signaling pathways, as well as the transcription factors c-Jun and ATF2 but not CHOP, mediated Lep-LPS-induced Fas/FasL expression and translocation. TLR2 but not TLR4 mediated Lep-LPS-induced JNK/p38 MAPK activation. Therefore, we demonstrated that a novel Fas-binding OMP and LPS of L. interrogans induce macrophage apoptosis through the Fas/FasL-caspase-8/-3 pathway.

Aiming at the problems of difficult and inefficient safety maintenance of hydraulic gates, this paper proposes an information fusion fault diagnosis method for hydraulic gates based on support vector machine (SVM) and improved D-S evidence theory. The method constructs feature subspaces by extracting information entropy features of wavelet packets of different sensor diagnostic signals, and then constructs diagnostic sub networks in each feature subspace. Finally, the input of each diagnostic sub-network is fused at the decision-making level by using improved evidence theory, so as to achieve the multi-information fusion diagnosis results of hydraulic gates. The experimental results of gate fault diagnosis show that the information fusion gate fault diagnosis method can effectively identify the types of radial gate faults, with a fault diagnosis accuracy of 98.33%, and high diagnostic reliability. The diagnostic uncertainty of various faults is less than 1%. The experimental results verify the feasibility of using intelligent fault diagnosis methods in the field of hydraulic gates, which is of great significance for improving the troubleshooting methods of hydraulic gates and promoting the development of intelligent water conservancy engineering. [ABSTRACT FROM AUTHOR]

Objective: To explore the curative effect of nano-Kuiyangye on radiation esophagitis in Wistar rats, and to explore its possible mechanism. Methods: Wistar rats were irradiated locally with 30Gy rays to establish an animal model of radiation esophagitis in rats. After irradiation, nano-Kuiyangye, traditional Chinese medicine ulcer solution, Kangfuxin solution, nano-hydrotalcite matrix, and distilled water were used to intervene continuously for 7 d, during which the body weight and food intake of the rats were recorded. On day 7, blood was collected from the abdominal aorta under anesthesia, and the serum was obtained by centrifugation. The expression levels of pain-related factors prostaglandin-2 (PGE-2), substance P (SP), and calcitonin gene-related peptide (CGRP) were detected by ELISA. Rats were sacrificed after blood collection, and full-length esophageal tissues were taken. Hematoxylin-eosin (HE) staining was performed to analyze the pathological changes of the rat esophagus, and Western Blotting was used to detect the expression of nuclear factor-κB (NF-κB) inflammatory protein. Results: Compared with the control group, the total food intake and body weight of the rats within 7 d after modeling were significantly decreased (P<0.05), and the expressions of pain-related factors PGE-2, SP, and CGRP were higher than those of the control group (P<0.05)., the esophageal pathological damage score increased (P<0.05), and the expression of NF-κB inflammatory protein increased (P<0.05); after treatment, the total food intake of the rats in the nano-Kuiyangye intervention group within 7 days after modeling was higher than that in other groups (P<0.05), the expressions of pain-related factors PGE-2, SP, and CGRP were lower than those in the model group (P<0.05), the esophageal pathological damage score was lower (P<0.05), and the expression of NF-κB inflammatory proteins was lower (P<0.05). Conclusion: Nano-Kuiyangye increases the food intake of rats with radiation esophagitis, reduces esophageal tissue damage, and reduces the concentration of serum pain factors; the anti-inflammatory effect of nano-Kuiyangye may be related to the reduction of NF-κB inflammatory factor levels. [ABSTRACT FROM AUTHOR]

Four undescribed sesquiterpenes (1–4) and 20 known sesquiterpenes (5–24) were obtained from the fruits of Litsea lancilimba Merr. by Small Molecule Accurate Recognition Technology (SMART). The gross structures and the relative configurations of the new compounds were deduced by spectroscopic data analysis. The absolute configurations were defined by comparison of their experimental and calculated electronic circular dichroism (ECD) spectra data. All compounds were screened for their neuroprotective effects against H 2 O 2 -induced SH-SY5Y cells injury. Compounds 2 , 3 , 7 , 8 and 13 exhibited comparable neuroprotective activity to the positive trolox at 50 μM. [Display omitted] • Four new sesquiterpenes (1–4) and 20 known sesquiterpenes (5 –24) were obtained from the plant by SMART. • The structures and absolute configurations of the new compounds were deduced by spectroscopic data analysis and ECD calculations. • Some compounds exhibited comparable neuroprotective effects to positive controls at 50 μ M. [ABSTRACT FROM AUTHOR]

Sarcandra glabra (Thunb.) Nakai is abundantly artificially cultivated for industrial use as an essential pharmaceutical and chemical raw material in China. In this work, five new meroterpenoids (1 – 5), along with one analog (6) and six known sesquiterpene dimers (7 – 12) were isolated from Sarcandra glabra. The chemical structures, including absolute configurations, were deduced by extensive spectroscopic methods combined with quantum mechanical electronic circular dichroism (ECD) and nuclear magnetic resonance (NMR) calculations, Mo 2 (OAc) 4 -induced ECD experiments, and customizable DP4 + probability analysis. Compounds 1 – 6 are biogenetically assembled by the cyclization of gentisicacid and monoterpene, featuring a novel 6/6/6 -fused ring system. Compounds 4 and 5 possess significant inhibitory effects on nitric oxide (NO) production against lipopolysaccharide (LPS)-induced microglia (BV2) cells, while compounds 8 and 9 displayed an approximately equal effect to Dexamethasone. The analysis of the protein-protein interaction (PPI) network and molecular docking showed 4 and 5 could play an anti-neuroinflammatory role by regulating heat shock proteins 90AA1 (Hsp90AA1). This study provided evidence for further research and utilization of S. glabra in anti-neuroinflammatory medicinal products. [Display omitted] • Five new meroterpenoids, along with one analog and six known sesquiterpene dimers were isolated from Sarcandra glabra. • Their structures were established by comprehensive spectroscopic analyses. • Compounds 4 and 5 possess significant anti-neuroinflammatory effects. • Compounds 4 and 5 could play an anti-neuroinflammatory role by regulating Hsp90AA1. [ABSTRACT FROM AUTHOR]

In the pursuit of a highly reversible lithium-oxygen (Li-O 2 ) battery, control of reaction sites to maintain stable conversion between O 2 and Li 2 O 2 at the cathode side is imperatively desirable. However, the mechanism involving the reaction site during charging remains elusive, which, in turn, imposes challenges in recognition of the origin of overpotential. Herein, via combined investigations by in situ atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS), we propose a universal morphology-dictated mechanism of efficient reaction sites for Li 2 O 2 decomposition. It is found that Li 2 O 2 deposits with different morphologies share similar localized conductivities, much higher than that reported for bulk Li 2 O 2 , enabling the reaction site not only at the electrode/Li 2 O 2 /electrolyte interface but also at the Li 2 O 2 /electrolyte interface. However, while the mass transport process is more enhanced at the former, the charge-transfer resistance at the latter is sensitively related to the surface structure and thus the reactivity of the Li 2 O 2 deposit. Consequently, for compact disk-like deposits, the electrode/Li 2 O 2 /electrolyte interface serves as the dominant decomposition site, which causes premature departure of Li 2 O 2 and loss of reversibility; on the contrary, for porous flower-like and film-like Li 2 O 2 deposits bearing a larger surface area and richer surface-active structures, both the interfaces are efficient for decomposition without premature departure of the deposit so that the overpotential arises primarily from the sluggish oxidation kinetics and the decomposition is more reversible. The present work provides instructive insights into the understanding of the mechanism of reaction sites during the charge process, which offers guidance for the design of reversible Li-O 2 batteries.