Institute of Microbiology of the Mediterranean
Recent publications
Drought stress is one of the most severe abiotic stresses affecting soil fertility and plant health, and due to climate change, it is destined to increase even further, becoming a serious threat to crop production. An efficient, eco-friendly alternative is the use of plant growth-promoting bacteria (PGPB), which can promote plant fitness through direct and indirect approaches, protecting plants from biotic and abiotic stresses. The present study aims to identify bacterial consortia to promote Spinacia oleracea L. cv Matador's seed germination and protect its seedlings from drought stress. Eight PGPB strains belonging to the Bacillus, Azotobacter, and Pseudomonas genera, previously characterized in physiological conditions, were analyzed under water-shortage conditions, and a germination bioassay was carried out by biopriming S. oleracea seeds with either individual strains or consortia. The consortia of B. amyloliquefaciens RHF6, B. amyloliquefaciens LMG9814, and B. sp. AGS84 displayed the capacity to positively affect seed germination and seedlings' radical development in both standard and drought conditions, ameliorating the plants' growth rate compared to the untreated ones. These results sustain using PGPB consortia as a valid ameliorating water stress strategy in the agro-industrial field.
This study analyzed the hydrodynamic structure of the estuary and plume of a large, tropical, and strongly-stratified river, the Magdalena. The Magdalena River is the largest source of fresh water and sediment of the Caribbean Sea and drastically impacts the morphodynamics and ecosystems along the Colombian coast. The analyses are based on the results of a calibrated and validated numerical model. Three scenarios of low, mid, and high freshwater discharge were analyzed to consider the seasonal variability of the mixing processes. The relative importance of three mixing mechanisms in the system is investigated, and the estuary and plume are subdivided into sectors depending on the dominant hydrodynamic processes at each sector. The results show that mixing in this system is mainly controlled by turbulence at the pycnocline, especially at the lift-off point in the transition between the estuary and the plume's near-field. A hydraulic jump occurs in the transition between the near- and mid-fields of the plume, but the mixing produced here is comparatively low since the plume has been mostly diluted already in the estuary and the near-field. During low and mid discharge scenarios, saline intrusion in the river channel forms a strongly stratified estuary where bottom propagated turbulence generates instabilities producing minor mixing. Meanwhile, the saltwater is flushed out of the river during the high discharge scenario, and pycnocline instabilities produce mixing at least one order of magnitude larger than during low discharge conditions. Coriolis acceleration does not seem to be a relevant driver of the plume behavior, despite the larger extension of the plume during high discharges, given the low latitude of the system.
Soil organic matter (SOM) plays a key role in the global carbon and nitrogen cycles. Soil biogeochemistry is regularly studied by extracting the base-soluble fractions of SOM: acid-insoluble humic acid (HA) and acid-soluble fulvic acid (FA). Electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry (ESI-FT-ICR-MS) is commonly utilized for molecularly characterizing these fractions. Different sample preparation techniques exist for the analysis of HA and FA though questions remain regarding data comparability following different preparations. Comparisons of different sample preparation techniques here revealed that the negative-mode ESI-FT-ICR-MS analytical window can be skewed to detect different groups of molecules, with primary differences in oxygenation, aromaticity, and molecular weight. It was also observed that HA and FA from soils versus an aquatic matrix behaved very differently. Thus, we conclude that sample preparation techniques determined to be "most optimal" in our study are in no way universal. We recommend that future studies of HA and FA involve similar comparative studies for determining the most suitable sample preparation technique for their particular type of HA or FA matrices. This will enhance data comparability among different studies and environmental systems and ultimately allow us to better understand the complex composition of environmental matrices.
In this work, we describe hypervariable-locus melting typing (HLMT), a novel fast approach to pathogen typing using the high-resolution melting (HRM) assay. The method includes a novel approach for gene target selection, primer design, and HRM data analysis.
Repairing oxidative‐targeted macromolecules is a central mechanism necessary for living organisms to adapt to oxidative stress. Reactive oxygen and chlorine species preferentially oxidize sulfur‐containing amino acids in proteins. Among these amino acids, methionine can be converted into methionine sulfoxide. This post‐translational oxidation can be reversed by methionine sulfoxide reductases, Msr enzymes. In Gram‐negative bacteria, the antioxidant MsrPQ system is involved in the repair of periplasmic oxidized‐proteins. Surprisingly, in this study we observed in Escherichia coli that msrPQ was highly expressed in the absence of oxygen. We have demonstrated that the anaerobic induction of msrPQ was due to chlorate (ClO3‐) contamination of the Casamino Acids. Molecular investigation led us to determine that the reduction of chlorate to the toxic oxidizing agent chlorite (ClO2‐) by the three nitrate reductases (NarA, NarZ and Nap) led to methionine oxidation of periplasmic proteins. In response to this stress the E. coli HprSR two‐component system was activated, leading to over‐production of MsrPQ. This study therefore supports the idea that methionine oxidation in proteins is part of chlorate toxicity, and that MsrPQ can be considered as an anti‐chlorate/chlorite defense system in bacteria. Finally, this study challenges the traditional view on the absence of Met‐oxidation during anaerobiosis. In E. coli, reduction of chlorate (ClO3‐) to the toxic oxidizing agent chlorite (ClO2‐) by the nitrate reductases leads to methionine oxidation of periplasmic proteins. In response to this stress the HprSR two‐component system is activated, leading to the over‐production of the periplasmic methionine sulfoxide reductase (MsrPQ) and the repair of the oxidized proteins.
Methionine residues are particularly sensitive to oxidation by reactive oxygen or chlorine species (ROS/RCS), leading to the appearance of methionine sulfoxide in proteins. This post-translational oxidation can be reversed by omnipresent protein repair pathways involving methionine sulfoxide reductases (Msr). In the periplasm of Escherichia coli , the enzymatic system MsrPQ, whose expression is triggered by the RCS, controls the redox status of methionine residues. Here we report that MsrPQ synthesis is also induced by copper stress via the CusSR two-component system, and that MsrPQ plays a role in copper homeostasis by maintaining the activity of the copper efflux pump, CusCFBA. Genetic and biochemical evidence suggest the metallochaperone CusF is the substrate of MsrPQ and our study reveals that CusF methionines are redox sensitive and can be restored by MsrPQ. Thus, the evolution of a CusSR-dependent synthesis of MsrPQ allows conservation of copper homeostasis under aerobic conditions by maintenance of the reduced state of Met residues in copper-trafficking proteins.
The importance of lipids as key players in the physiology, life cycle, and virulence of mycobacterial-related diseases, such as tuberculosis caused by the pathogenic bacteria M. tuberculosis, has been well established. These lipids participate in the host–pathogen cross-talk and play crucial roles in key cellular processes, including bacterial growth, virulence (reactivation and propagation), dormancy, cell wall biosynthesis, as well as in lipid storage and degradation. In this context, activity-based protein profiling has emerged as a powerful chemoproteomic strategy to identify and characterize the mycobacterial enzymes responsible for the synthesis and degradation of these lipids. Herein, we highlight the use of serine enzyme inhibitors as activity-based probes for the identification and characterization of the functional state of mycobacterial serine enzymes within the bacteria.
The idiosyncrasy of the lakesLakesof Sierra NevadaSierra Nevada lies in the fact that glacialGlacial retreat during their formation only occurred very close to the mountaintops and their proximity to North Africa. QuaternaryQuaternaryglaciersGlaciers’ retreat left a group of small lakesLakes close to the ridgelines with small catchment areas. These lakes are close to the Sahara Desert, where atmospheric mainstream transport toward the Iberian PeninsulaIberian Peninsula goes between 1500 and 4000 m above sea level. Therefore, the Sierra NevadaSierra Nevada Mountains constitutes the main physical barrier for this atmospheric dust, and Sierra NevadaSierra Nevada’s lakesLakes act as natural atmospheric collectors. Saharan dustSaharan dust intrusions and Atlantic fronts that reach the Sierra NevadaSierra Nevada have clear seasonal, synoptic, and climatic patterns that affect the quantity and quality of atmospheric deposition. The atmospheric deposition of Saharan dustSaharan dust has unique chemical and biological footprints. This chapter exposes the differences in the atmospheric deposition depending on the origin (marine vs. Saharan) of air masses that reach the Sierra NevadaSierra Nevada and their consequences for the lakes’ biogeochemistry. Atmospheric deposition with Saharan dustSaharan dust introduces macronutrients such as phosphorusPhosphorus (P) and micronutrients such as calciumCalcium (Ca) and ironIron to the lakesLakes. Atmospheric P inputs affect lake primary and bacterial productivity. The Ca content in the lakesLakes and their acid-neutralizing capacity is determined mainly by atmospheric deposition. Saharan dustSaharan dust also introduces organic matterOrganic matter with a humic-like signature and bacteria into the lakesLakes. In contrast, atmospheric deposition from marine sources introduces organic matterOrganic matter with an amino acid-like signature and a comparatively higher abundance of viruses. The atmospheric deposition of microorganisms has consequences for their distribution ranges and the formation of a microbial seed-bankMicrobial seed-banks to face future scenarios of environmental changesEnvironmental change.
Ionomers such as Nafion are used combined to redox enzymes in bioelectrocatalysis in order to prevent enzyme leakage and to enhance proton diffusion. In the search for an alternative to this costly and non-ecofriendly material, sulfonated poly(ether ether ketone) SPEEK, another ionomer free of perfluorinated functions can be envisioned. Here, we investigate the effect of ionomer type and concentration on enzymatic oxygen reduction by the Myrothecium verrucaria bilirubin oxidase (Mv BOD). We show that both SPEEK and Nafion ionomers reduce the catalytic activity of Mv BOD in enzymatic assays in solution as well as in electrochemical experiments once the enzyme is co-adsorbed with the ionomer. A pluridisciplinary approach associating microscopy, UV-Vis spectroscopy, dynamic light scattering, SDS gels and electrochemistry allows to point out a molecular interaction between the polymer particles and the enzyme governed by different principles depending SPEEK or Nafion is considered. The differences in hydrophilicity and conformation of SPEEK compared to Nafion account for a more severe effect on enzyme efficiency.
The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential.
Type Four Pili (T4P) are extracellular appendages mediating several bacterial functions such as motility, biofilm formation and infection. The ability to adhere to substrates is essential for all these functions. In Myxococcus xanthus, during twitching motility, the binding of polar T4P to exopolysaccharides (EPS), induces pilus retraction and the forward cell movement. EPS are produced, secreted and weakly associated to the M. xanthus cell surface or deposited on the substrate. In this study, a genetic screen allowed us to identify two factors involved in EPS-independent T4P-dependent twitching motility: the PilY1.1 protein and the HsfBA phosphorelay. Transcriptomic analyses show that HsfBA differentially regulates the expression of PilY1 proteins and that the down-regulation of pilY1.1 together with the accumulation of its homologue pilY1.3, allows twitching motility in the absence of EPS. The genetic and bioinformatic dissection of the PilY1.1 domains shows that PilY1.1 might be a bi-functional protein with a role in priming T4P extension mediated by its conserved N-terminal domain and roles in EPS-dependent motility mediated by an N-terminal DUF4114 domain activated upon binding to Ca2+. We speculate that the differential transcriptional regulation of PilY1 homologs by HsfBA in response to unknown signals, might allow accessorizing T4P tips with different modules allowing twitching motility in the presence of alternative substrates and environmental conditions.
Tau protein has been extensively studied due to its key roles in microtubular cytoskeleton regulation and in the formation of aggregates found in some neurodegenerative diseases. Recently it has been shown that zinc is able to induce tau aggregation by interacting with several binding sites. However, the precise location of these sites and the molecular mechanism of zinc-induced aggregation remain unknown. Here we used Nuclear Magnetic Resonance (NMR) to identify zinc binding sites on tau. These experiments revealed three distinct zinc binding sites on tau, located in the N-terminal part, the repeat region and the C-terminal part. Further analysis enabled us to show that the N-terminal and the C-terminal sites are independent of each other. Using molecular simulations, we proposed a model of each site in a complex with zinc. Given the clinical importance of zinc in tau aggregation, our findings pave the way for designing potential therapies for tauopathies.
Background The everolimus (EVE)-exemestane combination has been included in the International guidelines for metastatic HR+/HER2- breast cancer (mBC) since the results of the Bolero-2 trial. Marketing authorization has been granted in France in July 2012. A first report of the UNICANCER Epidemiological Strategy and Medical Economics (ESME) Research program described the real world use of everolimus therapy (ESMO 2017, #266). We report here updated data with long-term overall survival (OS) analyses, focusing on patients treated from 2012 onwards. Methods All patients (pts) who initiated treatment for a newly diagnosed mBC between 2008 and 2017 in all 18 French Comprehensive Cancer Centers have been included in the real life ESME database, which collects retrospective data using a clinical trial-like methodology. The primary endpoint of the present report was overall survival in pts who received everolimus. In order to adjust for differences between groups (EVE treated vs non EVE treated patients), we analyzed the impact of everolimus on OS and PFS by using a propensity score and inverse probability of treatment weighting (IPTW) sensitivity analyses, built with relevant cancer-related clinical variables in relation to survival and allocation of treatment. Those analyses were performed by line 1, 2 or 3 of treatment for mBC. Results The ESME program included 23,698 pts of whom 1897 with HR+/HER2- mBC received at least 1 dose of EVE and were diagnosed after 2012. Median age was 63 y (22-103). EVE pts were slightly younger than non-EVE pts (25.9% and 23.7% under 52 y, respectively, p=0.0574). EVE treated pts had more frequent non visceral metastases (52.3% vs 47.9%) and bone only metastases (38.5% vs 31.3%) at metastatic diagnosis, and less symptoms at mBC diagnosis (42.4% vs 47.5%) than non-EVE pts (all p values <.001). 94.3% of EVE pts had received an EVE-exemestane combination. EVE was administered either in the 1st, 2nd or 3rd line+ setting, in 3.3%, 14.7% and 25.3% of all cases respectively. At each line, treatments in the non-EVE treated pts included various endocrine therapy or chemotherapy regimen. Median follow-up was 47.9 m (0-98.7), and 61.4 m (2.1-98.7) for the overall- and EVE treated populations, respectively. Crude and landmark (6 and 12 months) OS analyses all suggested a longer OS with EVE based therapy. IPTW analyses by lines of treatment, comparing EVE-treated and non-EVE-treated patients, suggested a longer progression free survival with EVE when administered in the 3rd line setting (HR=0.82 CI95% [0.745-0.903], p<.0001). IPTW analyses consistently showed a significantly longer OS with EVE based treatment when administered in lines 1, 2 and 3 with respective HR values of 0.34, 0.34 and 0.23 (Table). Causes for EVE discontinuation were mainly disease progression (54%) and toxicity (26.6%). An exploratory analysis showed that 998 EVE treated patients (52.6%) also received a CDK4/6 inhibitor based treatment, mostly after EVE therapy (n=826, 82.8%). Median duration of CDK4/6 inhibitor therapy for those patients was 4.6 months (IQR 2.9-8.7). Conclusions These results are limited by the retrospective nature of the study and the lack of performance status, comorbidity or nutritional data. However, the long-term follow up of the ESME database suggests a favorable association between everolimus therapy and overall survival in HR+, HER2- mBC, persistent after IPTW adjusted analyses. HR (CI95%)p value12 months OS EVE vs not (unadjusted Kaplan Meier)Line 10.34 (0.16-072).005497% vs 93%Line 20.34 (0.22-0.52)<.000194% vs 85%Line 30.23 (0.14-0.36)<.000195% vs 79% Citation Format: Hélène Francois-Martin, Audrey Lardy-Cleaud, Barbara Pistilli, Christelle Levy, Véronique Diéras, Jean-Sébastien Frenel, Séverine Guiu, Marie-Ange Mouret-Reynier, Audrey Mailliez, Jean-Christophe Eymard, Thierry Petit, Mony Ung, Isabelle Desmoulins, Paule Augereau, Thomas Bachelot, Lionel Uwer, Marc Debled, Jean-Marc Ferrero, Corinne Veyret, Antony Goncalves, Michael Chevrot, Paul H Cottu. Long term results with everolimus in advanced hormone receptor positive breast cancer in a multicenter national real world observational study (ESME) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-19.
Background Toxoplasma gondii ( T. gondii ) is a highly successful parasite being able to cross all biological barriers of the body, finally reaching the central nervous system (CNS). Previous studies have highlighted the critical involvement of the blood–brain barrier (BBB) during T. gondii invasion and development of subsequent neuroinflammation. Still, the potential contribution of the choroid plexus (CP), the main structure forming the blood–cerebrospinal fluid (CSF) barrier (BCSFB) have not been addressed. Methods To investigate T. gondii invasion at the onset of neuroinflammation, the CP and brain microvessels (BMV) were isolated and analyzed for parasite burden. Additionally, immuno-stained brain sections and three-dimensional whole mount preparations were evaluated for parasite localization and morphological alterations. Activation of choroidal and brain endothelial cells were characterized by flow cytometry. To evaluate the impact of early immune responses on CP and BMV, expression levels of inflammatory mediators, tight junctions (TJ) and matrix metalloproteinases (MMPs) were quantified. Additionally, FITC-dextran was applied to determine infection-related changes in BCSFB permeability. Finally, the response of primary CP epithelial cells to T. gondii parasites was tested in vitro. Results Here we revealed that endothelial cells in the CP are initially infected by T. gondii , and become activated prior to BBB endothelial cells indicated by MHCII upregulation. Additionally, CP elicited early local immune response with upregulation of IFN-γ, TNF, IL-6, host-defence factors as well as swift expression of CXCL9 chemokine, when compared to the BMV. Consequently, we uncovered distinct TJ disturbances of claudins, associated with upregulation of MMP-8 and MMP-13 expression in infected CP in vivo, which was confirmed by in vitro infection of primary CP epithelial cells. Notably, we detected early barrier damage and functional loss by increased BCSFB permeability to FITC-dextran in vivo, which was extended over the infection course. Conclusions Altogether, our data reveal a close interaction between T. gondii infection at the CP and the impairment of the BCSFB function indicating that infection-related neuroinflammation is initiated in the CP.
Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems.
Ecological baselines for the structure and functioning of ecosystems in the absence of human activity can provide essential information on their health status. The Glorieuses islands are located in the Western Indian Ocean (WIO) and can be considered as “pristine” ecosystems that have not been subjected to anthropogenic pressure. Their nutrient context and the microbial assemblages were assessed by determining the abundance of heterotrophic prokaryotes (archaea and bacteria), picocyanobacteria, picoeukaryotes, microphytoplankton and protozooplankton communities in five stations, during two contrasted periods (November 2015 and May 2016). Chlorophyll-a concentrations were always under 1 μg/L and associated to very low levels in orthophosphates, nitrate and dissolved organic carbon, revealing an ultra-oligotrophic status for the Glorieuses waters. Picocyanobacteria confirmed the ultra-oligotrophic status with a predominance of Synechococcus. Zeaxanthin associated with the presence of picocyanobacteria represented the major pigment in both surveys. Three indices of diversity (species richness, Shannon and Pielou indexes) from microscopy observations highlighted the difference of diversity in microphytoplankton between the surveys. A focus on a 16S metabarcoding approach showed a high dominance of picocyanobacteria, Alpha- and Gammaproteobacteria, regardless of station or period. Multivariate analyses (co-inertia analyses) revealed a strong variability of ecological conditions between the two periods, with (i) high nutrient concentrations and heterotrophic nanoflagellate abundance in November 2015, and (ii) high heterotrophic prokaryote and picoeukaryote abundance in May 2016. The impact of a category 5 tropical cyclone (Fantala) on the regional zone in April 2016 is also advanced to explain these contrasted situations. Relative importance of top-down factors between bacterial and heterotrophic nanoflagellates was observed in November 2015 with an active microbial food web. All the results indicate that three microbial indexes potentially can be considered to assess the ecological change in Glorieuses marine waters.
Intrabacterial lipid Inclusions (ILIs), known as oil/fat bodies or adiposomes, are organelles found in intracellular pathogens, such as mycobacteria. They are composed of neutral lipids, mainly triacylglycerol, surrounded by a phospholipid monolayer containing a wide array of proteins. In the past decade, several groups have fostered the research on elucidating the ILI composition through the combination of a large panel of broad-range techniques, including proteomics, lipidomics, or metabolomics, portraying an unexpected level of complexity. Although ILIs with their associated proteins are thought to play various roles related to the metabolism and storage of neutral lipids, membrane biosynthesis, reduction of cytotoxicity and signal transduction; their exact role and contribution in virulence, their origin and evolution remain largely unknown. This chapter aims to summarize the current knowledge on the biology of ILI, their occurrence and evolution. It also reports the latest achievements regarding the procedures used to prepare and purify ILI as well as to cutting-edge methods, such as proximity labeling to identify protein partners associated with ILI. The access to newly discovered ILI-associated partners and their possible link with pathogenicity opens the path to a tremendous and fascinating emerging area in the mycobacterial field.
Two-component systems (TCS) are signalling pathways that allow bacterial cells to sense, respond and adapt to fluctuating environments. Among the classical TCS of Escherichia coli, HprSR has recently been shown to be involved in the regulation of msrPQ, which encodes the periplasmic methionine sulfoxide reductase system. In this study, we demonstrate that hypochlorous acid (HOCl) induces the expression of msrPQ in an HprSR-dependant manner, whereas H2O2, NO and paraquat (a superoxide generator) do not. Therefore, HprS appears to be an HOCl-sensing histidine kinase. Using a directed mutagenesis approach, we show that Met residues located in the periplasmic loop of HprS are important for its activity: as HOCl preferentially oxidizes Met residues, we provide evidence that HprS could be activated via the reversible oxidation of its methionine residues, meaning that MsrPQ plays a role in switching HprSR off. We propose that the activation of HprS by HOCl could occur through a Met redox switch. HprSR appears to be the first characterized TCS able to detect reactive chlorine species (RCS) in E. coli. This study represents an important step towards understanding the mechanisms of RCS resistance in prokaryotes. IMPORTANCE Understanding how bacteria respond to oxidative stress at the molecular level is crucial in the fight against pathogens. HOCl is one of the most potent industrial and physiological microbiocidal oxidants. Therefore bacteria have developed counterstrategies to survive HOCl-induced stress. Over the last decade, important insights into these bacterial protection factors have been obtained. Our work establishes HprSR as a reactive chlorine species-sensing, two-component system in Escherichia coli MG1655, which regulates the expression of MsrPQ, a repair system for HOCl-oxidized proteins. Moreover we provide evidence suggesting that HOCl could activate HprS through a methionine redox switch.
Democratisation theory has stressed the importance of active civil society participation (Schedler in J Democr 9: 91–107, 1998), (Diamond in Developing democracy: toward consolidation, Johns Hopkins University Press, Baltimore, 1999). This article uses Democratisation theory to argue that for civil society to have a positive impact on a state's democratisation process from a minimalist or electoral democracy to a pluralistic liberal system, it must have and exhibit a political culture conducive for supporting and promoting democratic ideals: a civic political culture (CPC). Welch’s conceptualisation of political culture (2013) determines that the latter manifests dualistically as discourse and practice. Therefore, this paper argues that to examine and test the extent to which a civil society’s political culture is democratic, a research approach that captures both the practises and discourses of political culture is essential. This article contributes to political culture research by advancing an effective application of Welch’s theory. Through a mixed-methods research design, this paper bridges the positivist-interpretivist methodological gap characteristic of political culture research. The application of the mixed-methods approach produces results with greater nuance and validity and provides evidence that post-2011 Tunisian civil society organisations (CSOs) are developing CPC.
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50 members
Sophie Bleves
  • LISM (UMR7255)
Henri-Pierre Fierobe
  • Laboratoire de Chimie Bactérienne
Marseille, France