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91.
Emilie Saby Jesper Buchhave Poulsen Just Justesen Merike Kelve Maria Jesus Uriz 《Biochimie》2009,91(11-12):1531-1534
Sponges [porifera], the most ancient metazoans, contain modules related to the vertebrate immune system, including the 2′,5′-oligoadenylate synthetase (OAS). The components of the antiviral 2′,5′-oligoadenylate (2–5A) system (OAS, 2′-Phosphodiesterase (2′-PDE) and RNAse L) of vertebrates have not all been identified in sponges. Here, we demonstrate for the first time that in addition to the OAS activity, sponges possess a 2′-PDE activity, which highlights the probable existence of a premature 2–5A system. Indeed, Suberites domuncula and Crella elegans exhibited this 2–5A degrading activity. Upon this finding, two out of three elements forming the 2–5A system have been found in sponges, only a endoribonuclease, RNAse L or similar, has to be found. We suspect the existence of a complex immune system in sponges, besides the self/non-self recognition system and the use of phagocytosis and secondary metabolites against pathogens. 相似文献
92.
Ugo Maninchedda Olivier M. Lepage Monika Gangl Sandrine Hilairet Bernard Remandet Francoise Meot Geraldine Penarier Emilie Segard Pierre Cortez Christian Jorgensen Régis Steinberg 《PloS one》2015,10(2)
The aim of this work was to develop an equine metacarpophalangeal joint model that induces osteoarthritis that is not primarily mediated by instability or inflammation. The study involved six Standardbred horses. Standardized cartilage surface damage or “grooves” were created arthroscopically on the distal dorsal aspect of the lateral and medial metacarpal condyles of a randomly chosen limb. The contralateral limb was sham operated. After 2 weeks of stall rest, horses were trotted 30 minutes every other day for 8 weeks, then evaluated for lameness and radiographed. Synovial fluid was analyzed for cytology and biomarkers. At 10 weeks post-surgery, horses were euthanized for macroscopic and histologic joint evaluation. Arthroscopic grooving allowed precise and identical damage to the cartilage of all animals. Under the controlled exercise regime, this osteoarthritis groove model displayed significant radiographic, macroscopic, and microscopic degenerative and reactive changes. Histology demonstrated consistent surgically induced grooves limited to non-calcified cartilage and accompanied by secondary adjacent cartilage lesions, chondrocyte necrosis, chondrocyte clusters, cartilage matrix softening, fissuring, mild subchondral bone inflammation, edema, and osteoblastic margination. Synovial fluid biochemistry and cytology demonstrated significantly elevated total protein without an increase in prostaglandin E2, neutrophils, or chondrocytes. This equine metacarpophalangeal groove model demonstrated that standardized non-calcified cartilage damage accompanied by exercise triggered altered osteochondral morphology and cartilage degeneration with minimal or inefficient repair and little inflammatory response. This model, if validated, would allow for assessment of disease processes and the effects of therapy. 相似文献
93.
Marine Henry Louis-Marie Bobay Anne Chevallereau Emilie Saussereau Pieter-Jan Ceyssens Laurent Debarbieux 《PloS one》2015,10(1)
In a previous study, six virulent bacteriophages PAK_P1, PAK_P2, PAK_P3, PAK_P4, PAK_P5 and CHA_P1 were evaluated for their in vivo efficacy in treating Pseudomonas aeruginosa infections using a mouse model of lung infection. Here, we show that their genomes are closely related to five other Pseudomonas phages and allow a subdivision into two clades, PAK_P1-like and KPP10-like viruses, based on differences in genome size, %GC and genomic contents, as well as number of tRNAs. These two clades are well delineated, with a mean of 86% and 92% of proteins considered homologous within individual clades, and 25% proteins considered homologous between the two clades. By ESI-MS/MS analysis we determined that their virions are composed of at least 25 different proteins and electron microscopy revealed a morphology identical to the hallmark Salmonella phage Felix O1. A search for additional bacteriophage homologs, using profiles of protein families defined from the analysis of the 11 genomes, identified 10 additional candidates infecting hosts from different species. By carrying out a phylogenetic analysis using these 21 genomes we were able to define a new subfamily of viruses, the Felixounavirinae within the Myoviridae family. The new Felixounavirinae subfamily includes three genera: Felixounalikevirus, PAK_P1likevirus and KPP10likevirus. Sequencing genomes of bacteriophages with therapeutic potential increases the quantity of genomic data on closely related bacteriophages, leading to establishment of new taxonomic clades and the development of strategies for analyzing viral genomes as presented in this article. 相似文献
94.
Cressida A. Madigan Amanda Jezek Martinot Jun-Rong Wei Ashoka Madduri Tan-Yun Cheng David C. Young Emilie Layre Jeffrey P. Murry Eric J. Rubin D. Branch Moody 《PLoS pathogens》2015,11(3)
The prolonged survival of Mycobacterium tuberculosis (M. tb) in the host fundamentally depends on scavenging essential nutrients from host sources. M. tb scavenges non-heme iron using mycobactin and carboxymycobactin siderophores, synthesized by mycobactin synthases (Mbt). Although a general mechanism for mycobactin biosynthesis has been proposed, the biological functions of individual mbt genes remain largely untested. Through targeted gene deletion and global lipidomic profiling of intact bacteria, we identify the essential biochemical functions of two mycobactin synthases, MbtK and MbtN, in siderophore biosynthesis and their effects on bacterial growth in vitro and in vivo. The deletion mutant, ΔmbtN, produces only saturated mycobactin and carboxymycobactin, demonstrating an essential function of MbtN as the mycobactin dehydrogenase, which affects antigenicity but not iron uptake or M. tb growth. In contrast, deletion of mbtK ablated all known forms of mycobactin and its deoxy precursors, defining MbtK as the essential acyl transferase. The mbtK mutant showed markedly reduced iron scavenging and growth in vitro. Further, ΔmbtK was attenuated for growth in mice, demonstrating a non-redundant role of hydroxamate siderophores in virulence, even when other M. tb iron scavenging mechanisms are operative. The unbiased lipidomic approach also revealed unexpected consequences of perturbing mycobactin biosynthesis, including extreme depletion of mycobacterial phospholipids. Thus, lipidomic profiling highlights connections among iron acquisition, phospholipid homeostasis, and virulence, and identifies MbtK as a lynchpin at the crossroads of these phenotypes. 相似文献
95.
Michael Macia Emilie Pecchi Christophe Vilmen Martine Desrois Carole Lan Bernard Portha Monique Bernard David Bendahan Beno?t Giannesini 《PloS one》2015,10(6)
Insulin resistance, altered lipid metabolism and mitochondrial dysfunction in skeletal muscle would play a major role in type 2 diabetes mellitus (T2DM) development, but the causal relationships between these events remain conflicting. To clarify this issue, gastrocnemius muscle function and energetics were investigated throughout a multidisciplinary approach combining in vivo and in vitro measurements in Goto-Kakizaki (GK) rats, a non-obese T2DM model developing peripheral insulin resistant without abnormal level of plasma non-esterified fatty acids (NEFA). Wistar rats were used as controls. Mechanical performance and energy metabolism were assessed strictly non-invasively using magnetic resonance (MR) imaging and 31-phosphorus MR spectroscopy (31P-MRS). Compared with control group, plasma insulin and glucose were respectively lower and higher in GK rats, but plasma NEFA level was normal. In resting GK muscle, phosphocreatine content was reduced whereas glucose content and intracellular pH were both higher. However, there were not differences between both groups for basal oxidative ATP synthesis rate, citrate synthase activity, and intramyocellular contents for lipids, glycogen, ATP and ADP (an important in vivo mitochondrial regulator). During a standardized fatiguing protocol (6 min of maximal repeated isometric contractions electrically induced at a frequency of 1.7 Hz), mechanical performance and glycolytic ATP production rate were reduced in diabetic animals whereas oxidative ATP production rate, maximal mitochondrial capacity and ATP cost of contraction were not changed. These findings provide in vivo evidence that insulin resistance is not caused by an impairment of mitochondrial function in this diabetic model. 相似文献
96.
Deepak Mittal Fabiana Saccheri Emilie Vénéreau Tobias Pusterla Marco E Bianchi Maria Rescigno 《The EMBO journal》2010,29(13):2242-2252
Skin cancers are the most commonly diagnosed cancers. Understanding what are the factors contributing to skin tumour development can be instrumental to identify preventive therapies. The myeloid differentiation primary response gene (MyD)88, the downstream adaptor protein of most Toll‐like receptors (TLR), has been shown to be involved in several mouse tumourigenesis models. We show here that TLR4, but not TLR2 or TLR9, is upstream of MyD88 in skin tumourigenesis. TLR4 triggering is not dependent on lipopolysaccharide associated to skin‐colonizing bacteria, but on the high mobility group box‐1 protein (HMGB1), an endogenous ligand of TLR4. HMGB1 is released by necrotic keratinocytes and is required for the recruitment of inflammatory cells and for the initiation of inflammation. The expression of TLR4 on both bone marrow‐derived and radioresistant cells is necessary for carcinogenesis. Consistently, a human tissue microarray analysis showed that melanoma and colon cancer display an over‐expression of TLR4 and its downstream adaptor protein MyD88 within tumours. Together, our results suggest that the initial release of HMGB1 triggers a TLR4‐dependent inflammatory response that leads to tumour development. 相似文献
97.
Alexandra Magro Christine Ducamp Felipe Ramon-Portugal Emilie Lecompte Brigitte Crouau-Roy Anthony Frederick George Dixon Jean-Louis Hemptinne 《Evolutionary ecology》2010,24(1):251-271
Faced with an ephemeral prey, aphidophagous ladybirds rely on the hydrocarbons present in the tracks of their larvae to choose
an unoccupied patch for egg laying. Although both conspecific and heterospecific larval tracks might deter females from oviposition,
the response to the later is often less striking. Several explanations have been suggested to account for this. In this paper
we tested the phylogeny hypothesis, which predicts that the chemical composition of the tracks of closely related species
of ladybirds will be more similar to one another than to those of more distantly related species. Qualitative and quantitative
information on the chemical nature of the larval tracks and a molecular phylogeny of seven species belonging to three different
genera are provided, and the congruence between these two sets of results assessed. The results confirm the phylogeny hypothesis
and infer a gradual mode of evolution of these infochemicals. 相似文献
98.
Sylvain Milla Cédric Mathieu Neil Wang Sophie Lambert Stéphanie Nadzialek Sophie Massart Emilie Henrotte Jessica Douxfils Charles Mélard S.N.M. Mandiki Patrick Kestemont 《Fish & shellfish immunology》2010,28(5-6):931-941
The effects of acute stress on immune status and its regulation by cortisol/corticosteroid receptors have received little attention in percids. To address that question, we investigated the physiological and immune responses of Eurasian perch, Perca fluviatilis to acute stress. We exposed immature perch to an 1-min exondation and measured at 1 h, 6 h, 24 h and 72 h post-stress: (1) stress-related parameters including plasma cortisol and glucose levels, (2) immune parameters in the plasma and in the spleen (complement, respiratory burst and lysozyme activity, total immunoglobulins; gene expression of lysozyme, complement unit 3, apolipoprotein A1 and 14 kDa, hepcidin and chemotaxin) (3) the corticosteroid receptors gene expression in the spleen after having cloned them. In addition, the in vitro effects of cortisol on the spleen immune parameters were also investigated.Plasma cortisol and glucose levels increased markedly 1 h post-stress and returned at basal levels after 24 h. P. fluviatilis mineralocorticoid receptor, but not glucocorticoid receptors, was significantly up-regulated both in vivo after the stress and in vitro by cortisol at a physiological concentration (100 ng/ml). The plasma immune parameters were not significantly affected by the stress. In contrast, spleno-somatic index, spleen lysozyme activity, lysozyme and hepcidin gene expression were depleted and total immunoglobulins increased along the whole time-course (1–72 h). But, these immune parameters were not regulated in vitro by cortisol at physiological or supra-physiological doses.Our results indicate that handling stress may affect spleen antibacterial defences without clear effects on circulating immune compounds and that the elevation of plasma cortisol after handling stress may not be related to the regulation of this splenic response. 相似文献
99.
The use of TNF-α antagonists has substantially improved the care of many patients with inflammatory and autoimmune diseases. However, approximately one third of such patients fail to respond well to treatment, regardless of the antagonist used or of the underlying disease. The mechanisms underlying these failures are analyzed in this review, and proposals made concerning how best to adapt therapeutic decisions in these instances. 相似文献
100.
Anis Larbi Filipe Cabreiro Henning Zelba Shiva Marthandan Emilie Combet Bertrand Friguet Isabelle Petropoulos Yvonne Barnett Graham Pawelec 《Free radical biology & medicine》2010,48(1):26-34
Cell culture and in vitro models are the basis for much biological research, especially in human immunology. Ex vivo studies of T cell physiology employ conditions attempting to mimic the in vivo situation as closely as possible. Despite improvements in controlling the cellular milieu in vitro, most of what is known about T cell behavior in vitro is derived from experiments on T cells exposed to much higher oxygen levels than are normal in vivo. In this study, we report a reduced proliferative response and increased apoptosis susceptibility after T cell activation at 2% oxygen compared to in air. To explain this observation, we tested the hypothesis of an impaired efficacy of intracellular protective mechanisms including antioxidant levels, oxidized protein repair (methionine sulfoxide reductases), and degradation (proteasome) activities. Indeed, after activation, there was a significant accumulation of intracellular oxidized proteins at more physiological oxygen levels concomitant with a reduced GSH:GSSG ratio. Proteasome and methionine sulfoxide reductase activities were also reduced. These data may explain the increased apoptotic rate observed at more physiological oxygen levels. Altogether, this study highlights the importance of controlling oxygen levels in culture when investigating oxygen-dependent phenomena such as oxidative stress. 相似文献