Laboratoire de Géographie Physique et Environnementale

MicroRNAs (miRNAs) are endogenous 21-24-nt RNAs that can down-regulate gene expression by pairing to the messages of protein-coding genes to specify mRNA cleavage or repression of productive translation. They act within the RNA-induced silencing complex (RISC), which in animals contains a member of the Argonaute family of proteins. In the present study, we show that Arabidopsis ago1 mutants have increased accumulation of mRNAs known to be targeted for cleavage by miRNAs. In hypomorphic ago1 alleles, this compromised miRNA function occurs without a substantial change in miRNA accumulation, whereas in null alleles it is accompanied by a drop in some of the miRNAs. Therefore, AGO1 acts within the Arabidopsis miRNA pathway, probably within the miRNA-programmed RISC, such that the absence of AGO1 destabilizes some of the miRNAs. We also show that targeting of AGO1 mRNA by miR168 is needed for proper plant development, illustrating the importance of feedback control by this miRNA. Transgenic plants expressing a mutant AGO1 mRNA with decreased complementarity to miR168 overaccumulate AGO1 mRNA and exhibit developmental defects partially overlapping with those of dcl1, hen1, and hyl1 mutants showing a decrease in miRNA accumulation. miRNA targets overaccumulate in miR168-resistant plants, suggesting that a large excess of AGO1 protein interferes with the function of RISC or sequesters miRNAs or other RISC components. Developmental defects induced by a miR168-resistant AGO1 mRNA can be rescued by a compensatory miRNA that is complementary to the mutant AGO1 mRNA, proving the regulatory relationship between miR168 and its target and opening the way for engineering artificial miRNAs in plants.

Background: To assess the worldwide variation of amyotrophic lateral sclerosis (ALS) incidence, we performed a systematic review and meta-analysis of population-based data published to date. Methods: We reviewed Medline and Embase up to June 2015 and included all population-based studies of newly diagnosed ALS cases, using multiple sources for case ascertainment. ALS crude and standardized incidence (on age and sex using the US 2010 population) were calculated. Random effect meta-analysis and meta-regression were performed using the subcontinent as the main study level covariate. Sources of heterogeneity related to the characteristics of the study population and the study methodology were investigated. Results: Among 3216 records, 44 studies were selected, covering 45 geographical areas in 11 sub-continents. A total of 13 146 ALS cases and 825 million person-years of follow-up (PYFU) were co-nsidered. The overall pooled worldwide crude ALS incidence was at 1.75 (1.55-1.96)/100 000 PYFU; 1.68 (1.50-1.85)/100 000 PYFU after standardization. Heterogeneity was identified in ALS standardized incidence between North Europe [1.89 (1.46-2.32)/100 000 PYFU] and East Asia [0.83 (0.42-1.24)/100 000 PYFU, China and Japan P = 0.001] or South Asia [0.73 (0.58-0.89)/100 000/PYFU Iran, P = 0.02]. Conversely, homogeneous rates have been reported in populations from Europe, North America and New Zealand [pooled ALS standardized incidence of 1.81 (1.66-1.97)/100 000 PYFU for those areas]. Conclusion: This review confirms a heterogeneous distribution worldwide of ALS, and sets the scene to sustain a collaborative study involving a wide international consortium to investigate the link between ancestry, environment and ALS incidence.

Abstract Riparian vegetation responds to hydrogeomorphic disturbances and environmental changes and also controls these changes. Here, we propose that the control of sediment erosion and deposition by riparian vegetation is a key geomorphological and ecological (i.e. biogeomorphic) function within fluvial corridors. In a 3 year study, we investigated the correlations between riparian vegetation and hydrogeomorphic dynamics along a transverse gradient from the main channel to the floodplain of the River Tech, France. Sediment erosion and deposition rates varied significantly along the transverse gradient as a function of the vegetation biovolume intercepting water flow. These effects, combined with the extremely strong mechanical resistance of pioneer woody structures and strong resilience of pioneer labile herbaceous communities, Populus nigra and Salix spp., explain the propensity of biogeomorphic succession (i.e. the synergy between vegetation succession and landform construction) to progress between destructive floods. This geomorphological function newly identified as an ‘ecosystem function’ per se encompasses the coupling of habitat and landform creation, maintenance and change with fundamental ecosystem structural changes in space and in time. Three different biogeomorphic functions, all related to the concept of ecosystem engineering, were identified: (i) the function of pioneer herbaceous communities to retain fine sediment and diaspores in the exposed zones of the active tract near the water resource, facilitating recruitment of further herbaceous and Salicacea species; (ii) the function of woody vegetation to drive the construction of forested islands and floodplains; and (iii) the function of stabilised riparian forests to act as ‘diversity reservoirs’ which can support regeneration after destructive floods. Overall, this study based on empirical data points to the fundamental importance of sediment flow control by pioneer riparian vegetation in defining fluvial ecosystem and landform organisation in time and in space. Copyright © 2009 John Wiley & Sons, Ltd.

The initial employment of tree rings in geomorphic studies was simply as a dating tool and only rarely were other environmental information and records of damage contained within the tree exploited. However, these annually resolved tree-ring records also preserve valuable archives of past geomorphic processes on timescales of decades to centuries. As many of these processes are significant natural hazards, understanding their distribution, timing and controls provides crucial information that can assist in the prediction, mitigation and defense against these hazards and their effects on society. This contribution aims at presenting a proposal on the types of growth disturbances to be included in future work focusing on geomorphic disturbance, the intensity of reactions, and on the minimum requirements needed for growth disturbances to be considered in event histories. We present possibilities and limitations of dendrogeomorphic applications in geomorphic research and propose a range of techniques and approaches that may become standard practice in the analysis and understanding of earth-surface processes and related natural hazards in the future.

The Teide and Pico Viejo stratocones and the NW and NE Rifts are products of the latest eruptive phase of the Island of Tenerife, initiated with the lateral collapse of its northern flank that formed the Cañadas Caldera and the Icod-La Guancha Valley at about 200 ka. The eruptive and structural evolution of this volcanic complex has been reconstructed after detailed geological mapping and radioisotopic dating of the significant eruptive events. A set of 54 new 14C and K/Ar ages provides precise age control of the recent eruptive history of Tenerife, particularly Teide Volcano, the third highest volcanic feature on earth (3718 m a.s.l.,>7 km high) and quite unique in terms of its intraplate setting. The development of the Teide-Pico Viejo volcanoes may be related to the activity of the NW and NE Rifts. Volcanic and intrusive activity along both rift zones may have played an important role in activating the gravitational landslide and in the subsequent growth, nested within the collapse embayment, of an increasingly higher central volcano with progressively differentiated magmas. The coeval growth of the central volcano with sustained activity along the rifts led to a clear bimodal distribution in composition of eruptive products, with the basaltic eruptions in the distal part of the rifts and phonolitic and more explosive eruptions in the central area, where the differentiated stratocones developed. Current volcanic hazard in Tenerife is considered to be moderate,

Abstract We propose a conceptual model of vegetation–hydrogeomorphology interactions and feedbacks within river corridors (i.e. river channels and their floodplains) that builds on previous similar hydrogeomorphologically centred models by incorporating hydrogeomorphological constraints on river corridor vegetation from region to reach scales; defining five dynamic river corridor zones within which different hydrogeomorphological processes are dominant so that plants and physical processes interact in different ways, and considering the potential distribution of these zones longitudinally from river headwaters to mouth, laterally across the river corridor, and in relation to different river planform styles; considering the way in which vegetation‐related landforms within each zone may reflect processes of self‐organization and the role of particular plant species as physical ecosystem engineers within the context of the dominant hydrogeomorphological processes; focussing, in particular, upon a ‘critical zone’ at the leading edge of plant–hydrogeomorphological process interactions that is located somewhere within the area of the river corridor perennially inundated by flowing water (zone 1) and the area that is frequently inundated and subject to both sediment erosion and deposition processes (zone 2). Within the critical zone some plant species strongly influence the position and character of the margin between the river channel and floodplain, affecting channel width, channel margin form and dynamics, and the transition from one river planform type to another; and considering the vegetated pioneer landforms that develop within the critical zone and how their morphological impact needs to be scaled to the river size. The model is illustrated using three example reaches from rivers within different biogeographical zones of Europe, and its potential application in the context of river management and restoration/rehabilitation is discussed. Copyright © 2015 John Wiley & Sons, Ltd.

International audience

Tree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794-2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.

Abstract Aim Within fluvial and coastal ecosystems world‐wide, flows of water, wind and sediment generate a shifting landscape mosaic composed of bare substrate and pioneer and mature vegetation successional stages. Pioneer plant species that colonize these ecosystems at the land–water interface have developed specific traits in response to environmental constraints (response traits) and are able to modify habitat conditions by modulating geomorphic processes (effect traits). Changes in the geomorphic environment under the control of engineer plants often feed back to organism traits (feedback traits), and thereby ecosystem functioning, leading to eco‐evolutionary dynamics. Here we explain the joint foundations of fluvial and coastal ecosystems according to feedback between plants and the geomorphic environment. Location Dynamic fluvial and coastal ecosystems world‐wide. Method Drawing from a pre‐existing model of ‘fluvial biogeomorphic succession’, we propose a conceptual framework showing that fluvial and coastal ‘biogeomorphic ecosystems’ are functionally similar due to eco‐evolutionary feedbacks between plants and geomorphology. Results The relationships between plant traits and their geomorphic environments within different fluvial and coastal biogeomorphic ecosystems are identified and classified within a framework of biogeomorphic functional similarity according to three criteria: (1) pioneer plants develop specific responses to the geomorphic environment; (2) engineer plants modulate the geomorphic environment; (3) geomorphic changes under biotic control within biogeomorphic ecosystems feed back to organisms. Main conclusions The conceptual framework of functional similarity proposed here will improve our capacity to analyse, compare, manage and restore fluvial and coastal biogeomorphic ecosystems world‐wide by using the same protocols based on the three criteria and four phases of the biogeomorphic succession model.

Magma transport through dikes is a major component of the development of monogenetic volcanic fields. These volcanic fields are characterized by numerous volcanic centers, each typically resulting from a single eruption. Therefore, magma must be transported from source to surface at different places, which raises the question of the relative importance of (1) the self‐propagation of magma through pristine rock and (2) the control exerted by pre‐existing fractures. To address this issue, we have carried out a series of analogue experiments to constrain the interaction of a propagating dike through a medium with pre‐existing fractures. The experiments involved the injection of air into an elastic gelatin solid, which was previously cut into its upper part to simulate pre‐existing fractures. The volume of the dikes, their distance from the fractures, and the ambient stress field were systematically varied to assess their influence on potential dike‐fracture interactions. The results show that distance and angle between dikes and fractures influence these interactions and the dike trajectory. Dike geometry and dynamics are also affected by both the presence of the fractures and the dike volume; dikes propagating in between fractures tend to decelerate. In nature, interactions are expected for dikes and fractures separated by less than about 200 m, and dikes with a volume less than about 10 −2 km 3 would experience a velocity decrease. These results highlight the influence of pre‐existing fractures on the mechanics and dynamics of dikes. These heterogeneities must be considered when studying the transport of magmas within the crust.

ABSTRACT Aim To contribute to the development of a macroevolutionary framework for riparian systems, reinforcing conceptual linkages between earth surface processes and biological and ecological processes. Location Riparian systems. Methods Literature review leading to an original proposition for perceiving the functioning of riparian systems in a new and different way. Results Riparian systems provide diverse landforms, habitats and resources for animals and plants. Certain organisms, defined as ‘ecosystem engineers’, significantly create and modify the physical components of riparian systems. Many studies have highlighted such engineering effects by animals on riparian systems, but the identification and understanding of the effects and responses of plants within fluvial corridors have emerged only recently. The modulation of matter, resources and energy flows by engineering plants helps establish characteristic sequences of fluvial landform creation and maintenance associated with synergetic ecological successions. We relate this process to the concept of niche construction, developed mainly by evolutionary biologists. Feedbacks between adaptive responses of riparian plants to flow regime and adjusting effects on biostabilization and bioconstruction are discussed in the context of niche construction at the scale of ecological succession and the evolution of organisms. Main conclusions Our conceptualization forges an integrated approach for understanding vegetated fluvial systems from a macroevolutionary perspective, for elucidating riparian ecosystem dynamics and potentially for establishing long‐term stream conservation and restoration strategies.

Abstract Numerical modelling of a rapid, partial destabilization of Anak Krakatau Volcano (Indonesia) was performed in order to investigate the tsunami triggered by this event. Anak Krakatau, which is largely built on the steep NE wall of the 1883 Krakatau eruption caldera, is active on its SW side (towards the 1883 caldera), which makes the edifice quite unstable. A hypothetical 0.280 km 3 flank collapse directed southwestwards would trigger an initial wave 43 m in height that would reach the islands of Sertung, Panjang and Rakata in less than 1 min, with amplitudes from 15 to 30 m. These waves would be potentially dangerous for the many small tourist boats circulating in, and around, the Krakatau Archipelago. The waves would then propagate in a radial manner from the impact region and across the Sunda Strait, at an average speed of 80–110 km h −1 . The tsunami would reach the cities located on the western coast of Java (e.g. Merak, Anyer and Carita.) 35–45 min after the onset of collapse, with a maximum amplitude from 1.5 (Merak and Panimbang) to 3.4 m (Labuhan). As many industrial and tourist infrastructures are located close to the sea and at altitudes of less than 10 m, these waves present a non-negligible risk. Owing to numerous reflections inside the Krakatau Archipelago, the waves would even affect Bandar Lampung (Sumatra, c . 900 000 inhabitants) after more than 1 h, with a maximum amplitude of 0.3 m. The waves produced would be far smaller than those occurring during the 1883 Krakatau eruption ( c. 15 m) and a rapid detection of the collapse by the volcano observatory, together with an efficient alert system on the coast, would possibly prevent this hypothetical event from being deadly.

Abstract. Mean properties of individual contrails are characterized for a wide range of jet aircraft as a function of age during their life cycle from seconds to 11.5 h (7.4–18.7 km altitude, −88 to −31 °C ambient temperature), based on a compilation of about 230 previous in situ and remote sensing measurements. The airborne, satellite, and ground-based observations encompass exhaust contrails from jet aircraft from 1972 onwards, as well as a few older data for propeller aircraft. The contrails are characterized by mean ice particle sizes and concentrations, extinction, ice water content, optical depth, geometrical depth, and contrail width. Integral contrail properties include the cross-section area and total number of ice particles, total ice water content, and total extinction (area integral of extinction) per contrail length. When known, the contrail-causing aircraft and ambient conditions are characterized. The individual datasets are briefly described, including a few new analyses performed for this study, and compiled together to form a contrail library (COLI). The data are compared with results of the Contrail Cirrus Prediction (CoCiP) model. The observations confirm that the number of ice particles in contrails is controlled by the engine exhaust and the formation process in the jet phase, with some particle losses in the wake vortex phase, followed later by weak decreases with time. Contrail cross sections grow more quickly than expected from exhaust dilution. The cross-section-integrated extinction follows an algebraic approximation. The ratio of volume to effective mean radius decreases with time. The ice water content increases with increasing temperature, similar to non-contrail cirrus, while the equivalent relative humidity over ice saturation of the contrail ice mass increases at lower temperatures in the data. Several contrails were observed in warm air above the Schmidt–Appleman threshold temperature. The emission index of ice particles, i.e., the number of ice particles formed in the young contrail per burnt fuel mass, is estimated from the measured concentrations for estimated dilution; maximum values exceed 1015 kg−1. The dependence of the data on the observation methods is discussed. We find no obvious indication for significant contributions from spurious particles resulting from shattering of ice crystals on the microphysical probes.

Abstract Slope movements (e.g. landslides) are dynamic systems that are complex in time and space and closely linked to both inherited and current preparatory and triggering controls. It is not yet possible to assess in all cases conditions for failure, reactivation and rapid surges and successfully simulate their transient and multi-dimensional behaviour and development, although considerable progress has been made in isolating many of the key variables and elementary mechanisms and to include them in physically-based models for landslide hazard assessments. Therefore, the objective of this paper is to review the state-of-the-art in the understanding of landslide processes and to identify some pressing challenges for the development of our modelling capabilities in the forthcoming years for hazard assessment. This paper focuses on the special nature of slope movements and the difficulties related to simulating their complex time-dependent behaviour in mathematical, physically-based models. It analyses successively the research frontiers in the recognition of first-time failures (pre-failure and failure stages), reactivation and the catastrophic transition to rapid gravitational processes (post-failure stage). Subsequently, the paper discusses avenues to transfer local knowledge on landslide activity to landslide hazard forecasts on regional scales and ends with an outline how geomorphological investigations and supporting monitoring techniques could be applied to improve the theoretical concepts and the modelling performance of physically-based landslide models at different spatial and temporal scales.

ABSTRACT Riverine ecosystems are recurrently rejuvenated during destructive flood events and vegetation succession starts again. Poplars (i.e. species from Populus genera) respond to hydrogeomorphological constraints, but, in turn, also influence these processes. Thus, poplar development on bare mineral substrates is not exclusively a one‐way vegetative process. Reciprocal interactions and adjustments between poplar species and sediment dynamics during their life cycle lead to the emergence of biogeomorphological entities within the fluvial corridor, such as vegetated islands, benches and floodplains. Based on a review of geomorphological, biological and ecological literature, we have identified and described the co‐constructing processes between riparian poplars and their fluvial environment. We have explored the possibility that the modification of the hydrogeomorphological environment exerted, in particular, by the European black poplar ( Populus nigra L.), increases its fitness and thus results in positive niche construction. We focus on the fundamental phases of dispersal, recruitment and establishment until sexual maturity of P . nigra by describing the hierarchy of interactions and the pattern of feedbacks between biotic and abiotic components. We explicitly relate the biological life cycle of P . nigra to the fluvial biogeomorphic succession model by referring to the ‘biogeomorphological life cycle’ of P . nigra . Finally, we propose new research perspectives based on this theoretical framework. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Abstract Local adaptation and phenotypic plasticity are two important characteristics of alpine plants to overcome the threats caused by global changes. Among alpine species, Arabis alpina is characterised by an unusually wide altitudinal amplitude, ranging from 800 to 3,100 m of elevation in the French Alps. Two non‐exclusive hypotheses can explain the presence of A. alpina across this broad ecological gradient: adaptive phenotypic plasticity or local adaptation, making this species especially useful to better understand these phenomena in alpine plant species. We carried out common garden experiments at two different elevations with maternal progenies from six sites that differed in altitude. We showed that (1) key phenotypic traits (morphotype, total fruit length, growth, height) display significant signs of local adaptation, (2) most traits studied are characterised by a high phenotypic plasticity between the two experimental gardens and (3) the two populations from the highest elevations lacked morphological plasticity compared to the other populations. By combining two genome scan approaches (detection of selection and association methods), we isolated a candidate gene (Sucrose‐Phosphate Synthase 1). This gene was associated with height and local average temperature in our studied populations, consistent with previous studies on this gene in Arabidopsis thaliana . Synthesis . Given the nature of the traits involved in the detected pattern of local adaptation and the relative lack of plasticity of the two most extreme populations, our findings are consistent with a scenario of a locally adaptive stress response syndrome in high elevation populations. Due to a reduced phenotypic plasticity, an overall low intra‐population genetic diversity of the adaptive traits and weak gene flow, populations of high altitude might have difficulties to cope with, e.g. a rise of temperature.

This review summarizes the key factors of a series of articles about animal plankton in rivers, a topic that remains poorly investigated. Running water, in which sampling processes are variable and often difficult, acts as a constraint as well as a resource for plankton. Assessment of the potamoplankton reveals that good swimmers of the true plankton are mixed with numerous poor swimmers among littoral and epibenthic forms. Small taxa dominate communities in most of rivers all over the world and, in comparison with crustaceans; the successful development of rotifers rests on their shorter development times. According to hydraulic and geomorphological features, the diversity of the habitats and the ability of individuals to avoid washout was examined, decrease in flow creating standing zones favourable to zooplankton development. Many species can find suitable conditions for the development of dense populations in stream habitats and examples of taxa-specific response, regardless of the habitat structure, are observed. While the challenge for riverine plankton remains ‘eat to be fruitful and multiply’, their activities have been poorly investigated in turbulent conditions, those able to continue growing in a current of 20 cm s−1, such as brachionid species, being usually dominant in rivers. Examination of the distribution of plankton populations, in the Middle Loire and in other rivers, showed that the flow regime, which plays a central role in organizing river habitats, explains the presence/absence of these fast-growing organisms. While reservoirs are major sources of crustaceans, lateral exchanges as well as downstream transport are important in determining the plankton. These ecosystems are primarily governed by abiotic factors, biological control taking place after physical control has happened. Because animals arrive by chance in any habitat during dispersion, zooplankton in rivers remains primarily governed by unpredictable physical processes and depends on the age of the water and the availability of habitats. In this way, the hydro-dynamics of river habitats need to be more documented with regard to their key role in the planktonic life. Preservation of the lentic areas remaining at the heart of the matter, the contrasting ecology of the rotifers should be a reliable tool with which to estimate the changes in habitats diversity of main channels, particularly during droughts, while crustacean's diversity would be more representative of flood plain annexes, particularly during flood events. Copyright © 2006 John Wiley & Sons, Ltd.

Abstract Earth surface processes and landforms may have coadjusted † with plant morphology, biomechanics and life‐history. We suggest that the colonization of land by plants at the early Silurian, and their propagation inside continents, represent critical phases of the coupling between geomorphic and biological processes on the Earth at a global scale. The consideration of this coupling involving geomorphic‐biological feedback mechanisms at the scales of ecological succession and organisms' evolution may promote the emergence of an evolutionary † geomorphology. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Abstract Little Ice Age lateral moraines represent one of the most important sediment storages and dynamic areas in glacier forelands. Following glacier retreat, simultaneous paraglacial adjustment and vegetation succession affect the moraine slopes. Geomorphic processes (e.g. debris flows, interrill erosion, gullying, solifluction) disturb and limit vegetation development, while increasing vegetation cover decreases geomorphic activity. Thus, feedbacks between geomorphic and vegetation dynamics strongly control moraine slope development. However, the conditions under which these biogeomorphic feedbacks can occur are insufficiently understood and major knowledge gaps remain. This study determines feedback conditions through the analysis of geomorphic and vegetation data from permanent plots in the Turtmann glacier foreland, Switzerland. Results from multivariate statistical analysis (i) confirm that Dryas octopetala L. is an alpine ecosystem engineer species which influences geomorphic processes on lateral moraines and thereby controls ecosystem structure and function, and (ii) demonstrate that biogeomorphic feedbacks can occur once geomorphic activity sufficiently decreases for D. octopetala to establish and cross a cover threshold. In the subsequent ecosystem engineering process, the dominant geomorphic processes change from flow and slide to bound solifluction. Increasing slope stabilization induces a decline in biogeomorphic feedbacks and the suppression of D. octopetala by shrubs. We conceptualize this relationship between process magnitude, frequency and species resilience and resistance to disturbances in a ‘biogeomorphic feedback window’ concept. Our approach enhances the understanding of feedbacks between geomorphic and alpine vegetation dynamics on lateral moraine slopes and highlights the importance of integrating geomorphic and ecological approaches for biogeomorphic research. Copyright © 2015 John Wiley &amp; Sons, Ltd.

CONTEXT: Only a few, small, human studies on E-cadherin and beta-catenin expression in normal cycling human endometrium have been reported. It remains unclear whether expression of these molecules might be altered in the endometrium of infertile patients with endometriosis. OBJECTIVES: The aim of the present study was to investigate E-cadherin and beta-catenin expression in the endometrium of infertile patients with endometriosis, those with uterine fibromas, and patients with unexplained infertility. DESIGN: Expression levels of E-cadherin and beta-catenin mRNA and/or protein in the endometrium of infertile patients with endometriosis (n = 151), those with uterine fibromas (n = 41), patients with unexplained infertility (n = 9), as well as healthy fertile controls (n = 57) were measured. This study utilized laser capture microdissection, real-time RT-PCR, and immunohistochemistry. RESULTS: No significant differences in E-cadherin or beta-catenin mRNA expression in microdissected epithelial cells were observed among the different groups throughout the menstrual cycle. However, very low or no protein expression of E-cadherin, total beta-catenin, or dephosphorylated beta-catenin in luminal and glandular epithelial cells was detected in the mid-secretory endometrium of healthy fertile controls. E-cadherin, total beta-catenin, and dephosphorylated beta-catenin protein expression in the mid-secretory endometrium of infertile patients with endometriosis or unexplained infertility was significantly higher compared to that of healthy fertile controls in both luminal and glandular epithelial cells. CONCLUSIONS: These findings suggest that impaired down-regulation of E-cadherin and beta-catenin protein expression, along with Wnt/beta-catenin signaling pathway activation during the window of implantation, might be one of the potential molecular mechanisms of infertility in patients with endometriosis.