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61.
Agathe Dutt Rault Anthony Didier Andrivon Stéphane Jumel Gwenola Le Roy Alain Baranger Melen Leclerc Christophe Le May 《Oikos》2021,130(4):652-667
Multi-infections may result in either competitive exclusion or coexistence on the same host of pathogen genotypes belonging to the same or different species. Epidemiological consequences of multiple infections, particularly how the development and transmission of a pathogen can be modified by the presence of another pathogen, are well documented. However, understanding how life history strategies of each pathogen modulate co-infection outcomes remains quite elusive. To analyze how co-infection drives changes in life history traits and affects co-existence in epidemic pathogens, we infected detached pea stipules with two fungal species, Peyronellaea pinodes and Phoma medicaginis var. pinodella (considering two strains per species), part of the ascochyta blight complex but presenting different life history strategies. All pairwise combinations (including self-pairs) between two strains of each species were tested. Strains were inoculated simultaneously, but apart from one another on the stipule. For each strain, four life history traits were measured: incubation period, necrosis area six days after inoculation, latent period and offspring production. Results show that, in co-infection, when resources are highly allocated to lesion development, the time between inoculation and the appearance of reproduction structures (latent period) and offspring production decreased, and vice-versa relative to single infections. The direction and/or magnitude of these responses to co-infection depend on the co-infecting strains. Moreover, these changes were always higher in self-pairs than in mixed co-infections. These results suggest facilitation between co-infecting strains, resulting in the selection of an intermediate level of virulence (here measured as the lesion development) at the expense of pathogen offspring production. This strategy allows the development and reproduction of each co-infecting strain when sharing limited resources. However, the direction and strength of these life history traits variations in co-infection depend on the life history strategy of the co-infecting strains, with a clear difference between ‘opportunists', ‘scavengers' and ‘pioneer colonisers'. 相似文献
62.
Hertel F Switalski A Mintert-Jancke E Karavassilidou K Bender K Pott L Kienitz MC 《PloS one》2011,6(6):e20855
Background
Most ion channels are regulated by phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) in the cell membrane by diverse mechanisms. Important molecular tools to study ion channel regulation by PtdIns(4,5)P2 in living cells have been developed in the past. These include fluorescent PH-domains as sensors for Förster resonance energy transfer (FRET), to monitor changes in plasma membrane. For controlled and reversible depletion of PtdIns(4,5)P2, voltage-sensing phosphoinositide phosphatases (VSD) have been demonstrated as a superior tool, since they are independent of cellular signaling pathways. Combining these methods in intact cells requires multiple transfections. We used self-cleaving viral 2A-peptide sequences for adenovirus driven expression of the PH-domain of phospholipase-Cδ1 (PLCδ1) fused to ECFP and EYFP respectively and Ciona intestinalis VSP (Ci-VSP), from a single open reading frame (ORF) in adult rat cardiac myocytes.Methods and Results
Expression and correct targeting of ECFP-PH-PLCδ1, EYFP-PH-PLCδ1, and Ci-VSP from a single tricistronic vector containing 2A-peptide sequences first was demonstrated in HEK293 cells by voltage-controlled FRET measurements and Western blotting. Adult rat cardiac myocytes expressed Ci-VSP and the two fluorescent PH-domains within 4 days after gene transfer using the vector integrated into an adenoviral construct. Activation of Ci-VSP by depolarization resulted in rapid changes in FRET ratio indicating depletion of PtdIns(4,5)P2 in the plasma membrane. This was paralleled by inhibition of endogenous G protein activated K+ (GIRK) current. By comparing changes in FRET and current, a component of GIRK inhibition by adrenergic receptors unrelated to depletion of PtdIns(4,5)P2 was identified.Conclusions
Expression of a FRET sensor pair and Ci-VSP from a single ORF provides a useful approach to study regulation of ion channels by phosphoinositides in cell lines and transfection-resistant postmitotic cells. Generally, adenoviral constructs containing self-cleaving 2A-peptide sequences are highly suited for simultaneous transfer of multiple genes in adult cardiac myocytes. 相似文献63.
Sanchez K Papelard A Nguyen C Bendeddouche I Jousse M Rannou F Revel M Poiraudeau S 《PloS one》2011,6(5):e20274
Objective
To assess the sensitivity to change of the McMaster Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR) in chronic low back pain (CLBP) and shifts in patients'' priorities of disabling activities over time.Methods
A prospective longitudinal survey of 100 patients (38 males) with CLBP in a tertiary care teaching hospital. Evaluation at baseline and 6 months by the MACTAR, Quebec Back Pain Disability Questionnaire (QUEBEC), Hospital Anxiety and Depression scale (HAD), Fear-Avoidance Beliefs Questionnaire (FABQ), Coping Strategies Questionnaire (CSQ), and pain and handicap visual analogue scales (VASs). Patients'' perceived improvement or worsening of condition was assessed at 6 months. Effect size (ES) and Standardized response mean (SRM) and effect size (ES) were used to evaluate sensitivity to change of the MACTAR.Results
The MACTAR SRM and ES values (SRM = 0.25; ES = 0.37) were among the highest for the instruments evaluated. For patients considering their condition as improved, the SRM was 0.66 and the ES 1. The 3 disability domains, classified by the International Classification of Functioning, Disability and Health (ICF), most often cited as priorities at baseline remained the most cited at follow-up: mobility (40.9% of patients); community, social and civic life (22.7%); and domestic life (22.4%). At 6 months, 48 patients shifted their priorities, for a decrease in MACTAR SRM and ES values for patients considering their condition improved and an increase in these values for those considering their condition deteriorated.Conclusions
Although the MACTAR has similar sensitivity to change as other outcome measures widely used in CLBP, shifts in patient priorities over time are common and influence scores and sensitivity to change. 相似文献64.
Nguyen C Bérezné A Baubet T Mestre-Stanislas C Rannou F Papelard A Morell-Dubois S Revel M Guillevin L Poiraudeau S Mouthon L;Groupe Français de Recherche sur la Sclérodermie 《PloS one》2011,6(3):e17551
Objectives
To assess the association of gender with clinical expression, health-related quality of life (HRQoL), disability, and self-reported symptoms of depression and anxiety in patients with systemic sclerosis (SSc).Methods
SSc patients fulfilling the American College of Rheumatology and/or the Leroy and Medsger criteria were assessed for clinical symptoms, disability, HRQoL, self-reported symptoms of depression and anxiety by specific measurement scales.Results
Overall, 381 SSc patients (62 males) were included. Mean age and disease duration at the time of evaluation were 55.9 (13.3) and 9.5 (7.8) years, respectively. One-hundred-and-forty-nine (40.4%) patients had diffuse cutaneous SSc (dcSSc). On bivariate analysis, differences were observed between males and females for clinical symptoms and self-reported symptoms of depression and anxiety, however without reaching statistical significance. Indeed, a trend was found for higher body mass index (BMI) (25.0 [4.1] vs 23.0 [4.5], p = 0.013), more frequent dcSSc, echocardiography systolic pulmonary artery pressure >35 mmHg and interstitial lung disease in males than females (54.8% vs 37.2%, p = 0.010; 24.2% vs 10.5%, p = 0.003; and 54.8% vs 41.2%, p = 0.048, respectively), whereas calcinosis and self-reported anxiety symptoms tended to be more frequent in females than males (36.0% vs 21.4%, p = 0.036, and 62.3% vs 43.5%, p = 0.006, respectively). On multivariate analysis, BMI, echocardiography PAP>35 mmHg, and anxiety were the variables most closely associated with gender.Conclusions
In SSc patients, male gender tends to be associated with diffuse disease and female gender with calcinosis and self-reported symptoms of anxiety. Disease-associated disability and HRQoL were similar in both groups. 相似文献65.
Chrysomyxa rusts are fungal pathogens widely present in the boreal forest. Taxonomic delimitation and precise species identification are difficult within this genus because several species display similar morphological features. We applied a DNA barcode system based on the ribosomal internal transcribed spacer region (ITS), large subunit (28S) ribosomal RNA gene, mitochondrial cytochrome oxidase 1 (CO1) and mitochondrial NADH dehydrogenase subunit 6 (NAD6) in 86 strains from 16 different Chrysomyxa species, including members of the Chrysomyxa ledi species complex. The nuclear ITS and 28S loci revealed higher resolving power than the mitochondrial genes. Amplification of the full CO1 barcode region failed due to the presence of introns limiting the dataset obtained with this barcode. In most cases the ITS barcodes were in agreement with taxonomic species based on phenotypic characters. Nevertheless we observed genetically distinct (different DNA barcodes) lineages within Chrysomyxa pyrolae and Chrysomyxa rhododendri, providing some evidence for allopatric speciation within these morphologically defined species. This finding, together with the observed pattern of host specificities of the studied rust fungi, suggest that species diversification within the C. ledi species complex might be governed by a set of factors such as specialisation to certain Ericaceae species as telial hosts and to a lesser extent specialization to different spruce species as aecial hosts. Moreover allopatric speciation by geographic disruption of species also seems to take place. When our data were integrated into a broader phylogenetic framework the Chrysomyxa genus unexpectedly was not resolved as a monophyletic group. Indeed the spruce cone rusts C. pyrolae and C. monesis coalesced with the pine needle rusts belonging to the genus Coleosporium, whereas the microcyclic species Chrysomyxa weirii was embedded within a clade comprising the genus Melampsora. 相似文献
66.
Rousseaux C Thuru X Gelot A Barnich N Neut C Dubuquoy L Dubuquoy C Merour E Geboes K Chamaillard M Ouwehand A Leyer G Carcano D Colombel JF Ardid D Desreumaux P 《Nature medicine》2007,13(1):35-37
Abdominal pain is common in the general population and, in patients with irritable bowel syndrome, is attributed to visceral hypersensitivity. We found that oral administration of specific Lactobacillus strains induced the expression of mu-opioid and cannabinoid receptors in intestinal epithelial cells, and mediated analgesic functions in the gut-similar to the effects of morphine. These results suggest that the microbiology of the intestinal tract influences our visceral perception, and suggest new approaches for the treatment of abdominal pain and irritable bowel syndrome. 相似文献
67.
Yann Ferrandez Manuela Dezi Mickael Bosco Agathe Urvoas Marie Valerio-Lepiniec Christel Le Bon Fabrice Giusti Isabelle Broutin Grégory Durand Ange Polidori Jean-Luc Popot Martin Picard Philippe Minard 《The Journal of membrane biology》2014,247(9-10):925-940
Specific, tight-binding protein partners are valuable helpers to facilitate membrane protein (MP) crystallization, because they can i) stabilize the protein, ii) reduce its conformational heterogeneity, and iii) increase the polar surface from which well-ordered crystals can grow. The design and production of a new family of synthetic scaffolds (dubbed αReps, for “artificial alpha repeat protein”) have been recently described. The stabilization and immobilization of MPs in a functional state are an absolute prerequisite for the screening of binders that recognize specifically their native conformation. We present here a general procedure for the selection of αReps specific of any MP. It relies on the use of biotinylated amphipols, which act as a universal “Velcro” to stabilize, and immobilize MP targets onto streptavidin-coated solid supports, thus doing away with the need to tag the protein itself. 相似文献
68.
Agata Nawrotek Beatriz G. Guimar?es Christophe Velours Agathe Subtil Marcel Knossow Beno?t Gigant 《The Journal of biological chemistry》2014,289(36):25199-25210
Although the actin network is commonly hijacked by pathogens, there are few reports of parasites targeting microtubules. The proposed member of the LcrE protein family from some Chlamydia species (e.g. pCopN from C. pneumoniae) binds tubulin and inhibits microtubule assembly in vitro. From the pCopN structure and its similarity with that of MxiC from Shigella, we definitively confirm CopN as the Chlamydia homolog of the LcrE family of bacterial proteins involved in the regulation of type III secretion. We have also investigated the molecular basis for the pCopN effect on microtubules. We show that pCopN delays microtubule nucleation and acts as a pure tubulin-sequestering protein at steady state. It targets the β subunit interface involved in the tubulin longitudinal self-association in a way that inhibits nucleotide exchange. pCopN contains three repetitions of a helical motif flanked by disordered N- and C-terminal extensions. We have identified the pCopN minimal tubulin-binding region within the second and third repeats. Together with the intriguing observation that C. trachomatis CopN does not bind tubulin, our data support the notion that, in addition to the shared function of type III secretion regulation, these proteins have evolved different functions in the host cytosol. Our results provide a mechanistic framework for understanding the C. pneumoniae CopN-specific inhibition of microtubule assembly. 相似文献
69.
Laurent Hardion Régine Verlaque Kristin Saltonstall Agathe Leriche Bruno Vila 《Annals of botany》2014,114(3):455-462
Background and Aims
The hypothesis of an ancient introduction, i.e. archaeophyte origin, is one of the most challenging questions in phylogeography. Arundo donax (Poaceae) is currently considered to be one of the worst invasive species globally, but it has also been widely utilzed by man across Eurasia for millennia. Despite a lack of phylogenetic data, recent literature has often speculated on its introduction to the Mediterranean region.Methods
This study tests the hypothesis of its ancient introduction from Asia to the Mediterranean by using plastid DNA sequencing and morphometric analysis on 127 herbarium specimens collected across sub-tropical Eurasia. In addition, a bioclimatic species distribution model calibrated on 1221 Mediterranean localities was used to identify similar ecological niches in Asia.Key Results
Despite analysis of several plastid DNA hypervariable sites and the identification of 13 haplotypes, A. donax was represented by a single haplotype from the Mediterranean to the Middle East. This haplotype is shared with invasive samples worldwide, and its nearest phylogenetic relatives are located in the Middle East. Morphometric data characterized this invasive clone by a robust morphotype distinguishable from all other Asian samples. The ecological niche modelling designated the southern Caspian Sea, southern Iran and the Indus Valley as the most suitable regions of origin in Asia for the invasive clone of A. donax.Conclusions
Using an integrative approach, an ancient dispersion of this robust, polyploid and non-fruiting clone is hypothesized from the Middle East to the west, leading to its invasion throughout the Mediterranean Basin. 相似文献70.
Enrique Casalino Christophe Choquet Agathe Leleu Romain Hellmann Mathias Wargon Gaelle Juillien Yazdan Yazdanpanah Elisabeth Bouvet 《PloS one》2014,9(8)