On the fate of sexual traits under asexuality.

Environmental shifts and life-history changes may result in formerly adaptive traits becoming non-functional or maladaptive. In the absence of pleiotropy and other constraints, such traits may decay as a consequence of neutral mutation accumulation or selective processes, highlighting the importance of natural selection for adaptations. A suite of traits are expected to lose their adaptive function in asexual organisms derived from sexual ancestors, and the many independent transitions to asexuality allow for comparative studies of parallel trait maintenance versus decay. In addition, because certain traits, notably male-specific traits, are usually not exposed to selection under asexuality, their decay would have to occur as a consequence of drift. Selective processes could drive the decay of traits associated with costs, which may be the case for the majority of sexual traits expressed in females. We review the fate of male and female sexual traits in 93 animal lineages characterized by asexual reproduction, covering a broad taxon range including molluscs, arachnids, diplopods, crustaceans and eleven different hexapod orders. Many asexual lineages are still able occasionally to produce males. These asexually produced males are often largely or even fully functional, revealing that major developmental pathways can remain quiescent and functional over extended time periods. By contrast, for asexual females, there is a parallel and rapid decay of sexual traits, especially of traits related to mate attraction and location, as expected given the considerable costs often associated with the expression of these traits. The level of decay of female sexual traits, in addition to asexual females being unable to fertilize their eggs, would severely impede reversals to sexual reproduction, even in recently derived asexual lineages. More generally, the parallel maintenance versus decay of different trait types across diverse asexual lineages suggests that neutral traits display little or no decay even after extended periods under relaxed selection, while extensive decay for selected traits occurs extremely quickly. These patterns also highlight that adaptations can fix rapidly in natural populations of asexual organisms, in spite of their mode of reproduction.

Genotype-level interactions determine the degree of reduction of leaf rust on wheat by seed application of beneficial Pseudomonas spp.

Some bacteria have the capacity to reduce incidence and severity of plant diseases either by inhibiting the pathogen or by modulating the resistance response of the plant. Plants dispose of different resistance mechanisms that are influenced by the biotic and abiotic environment. The present experiments explored the effects of biocontrol strains of Pseudomonas fluorescens on the resistance of wheat varieties against brown rust disease caused by Puccinia triticina. Root inoculation with biocontrol pseudomonads reduced the disease severity on the leaves. The plant response depended on the genotype of both the microbes and the wheat varieties, suggesting a straight interaction at the molecular level.

Altering in vivo fate of heart-infiltrating progenitors from pro-fibrotic into F4/80+macrophages prevents progression of myocarditis into inflammatory dilated cardiomyopathy

Rationale: Experimental autoimmune myocarditis (EAM) mirrors important pathogenic aspects of inflammatory cardiomyopathy, a common cause of heart failure. In EAM, TGF-β-dependent conversion of heart-infiltrating prominin-1+ progenitors into myofibroblasts is critical for development of fibrosis and the end-stage heart failure phenotype. Therapeutic strategies modulating the in vivo fate of prominin-1+ progenitors might therefore prevent TGF-β-mediated cardiac fibrosis and pathological remodelling. Methods and Results: EAM was induced in BALB/c mice using alpha-myosin heavy chain (aMyHC) peptide/complete Freund's adjuvant (CFA) immunization. Prominin-1+ cells were isolated from the inflamed hearts at day 21 after immunization, expanded and treated with Macrophage Colony-Stimulating Factor (M-CSF) or Transforming Growth Factor-beta (TGF-β). Herein, we demonstrated that M-CSF turns, ex vivo and in the EAM, heart-infiltrating prominin-1+ progenitors into immunosuppressive F4/80/CD11b/CD16/32/NOS2-expressing, nitric oxide producing and E.coli bacteria phygocyting macrophages, and protect further TGF-β-stimulated differentiation into pathogenic myofibroblasts. Systemic M-CSF treatment during myocarditis completely prevented post-inflammatory fibrosis, T cell relapse and left ventricular dysfunction. Mechanistically, M-CSF-induced macrophage differentiation from prominin-1+ progenitors critically required nitric oxide synthase 2. Accordingly, M-CSF treatment failed to reduce myocardial fibrosis development in Nos2-/- mice. Conclusions: Altering the in vivo fate of inflammatory prominin-1 expressing progenitors from pro-fibrotic into the F4/80 expressing macrophage phenotype protects from myocarditis progression, cardiac fibrosis, and heart failure. These findings offer a modern therapeutic model and challenge former concepts, which attributed macrophages a detrimental role in inflammatory cardiomyopathy progression.

Deficient T cell fate specification in mice with an induced inactivation of Notch1.

Notch proteins are cell surface receptors that mediate developmental cell specification events. To explore the function of murine Notch1, an essential portion of the gene was flanked with loxP sites and inactivation induced via interferon-regulated Cre recombinase. Mice with a neonatally induced loss of Notch1 function were transiently growth retarded and had a severe deficiency in thymocyte development. Competitive repopulation of lethally irradiated wild-type hosts with wild-type- and Notch1-deficient bone marrow revealed a cell autonomous blockage in T cell development at an early stage, before expression of T cell lineage markers. Notch1-deficient bone marrow did, however, contribute normally to all other hematopoietic lineages. These findings suggest that Notch1 plays an obligatory and selective role in T cell lineage induction.

Anionic Sites, Fucose Residues and Class I Human Leukocyte Antigen Fate During Interaction of Toxoplasma gondii with Endothelial Cells

Toxoplasma gondii invades and proliferates in human umbilical vein endothelial cells where it resides in a parasitophorous vacuole. In order to analyze which components of the endothelial cell plasma membrane are internalized and become part of the parasitophorous vacuole membrane, the culture of endothelial cells was labeled with cationized ferritin or UEA I lectin or anti Class I human leukocytte antigen (HLA) before or after infection with T. gondii. The results showed no cationized ferritin and UEA I lectin in any parasitophorous vacuole membrane, however, the Class I HLA molecule labeling was observed in some endocytic vacuoles containing parasite until 1 h of interaction with T. gondii. After 24 h parasite-host cell interaction, the labeling was absent on the vacuolar membrane, but presents only in small vesicles near parasitophorous vacuole. These results suggest the anionic site and fucose residues are excluded at the time of parasitophorous vacuole formation while Class I HLA molecules are present only on a minority of Toxoplasma-containig vacuoles.

Three new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from the double-collared seed eater, Sporophila caerulescens (Passeriformes: Emberizidae), from Eastern Brazil

Three isosporan species are described from the double-collared seedeater, Sporophila caerulescens from Eastern Brazil. Isospora sporophilae n. sp. oocysts spherical to subspherical; oocyst wall bi-layered, smooth, inner layer colorless to pale yellowish, 21.6 × 20.9 (19.20-23.20 × 18.40-22.60) µm, shape-index 1.03 ± 0.02 (1-1.10), with no micropyle or oocyst residuum. Polar bodies splinter-like or comma-like. Sporocysts ovoidal, 15.2 × 10.6 (17.40-12.80 × 12.60-8.40) µm, shape-index 1.43 ± 0.14 (1.17-1.81), with knob-like Stieda body and residuum. Large crystalloid body in the center of the sporocyst. Isospora flausinoi n. sp. oocysts spherical to subspherical, oocyst wall bi-layered, smooth, colorless, 17.30 x 16.53 (14-20 × 13.60-20) µm, shape-index 1.05 ± 0.04 (1-1.21). Micropyle and oocyst residuum absent; presence of a large polar body. Sporocyst piriform, 14.88 x 10.70 (11.80-18 × 8-12.40) µm, shape-index 1.40 ± 0.18 (1.07-1.77), with smooth, thin, single-layered wall. Sporocyst with rounded Stieda body with no substieda body, and residuum composed of granular material. Isospora teixeirafilhoi n. sp. oocysts spherical to subspherical, oocyst wall bi-layered, smooth, colorless, 17.41 x 16.81 (15.60 19.40 × 14.20-18.80) µm. Shape-index 1.04 ± 0.08 (1-1.12). Micropyle and oocyst residuum absent; presence of a small double-lobuled polar body. Sporocyst ovoid, 11.74 × 8.12 (9-14.20 × 6.20-9.40) µm. Shape-index 1.46 ± 0.23 (1.06-1.88). Sporocyst with knob-like Stieda body, no sub-Stieda body and residuum composed of granular material.

Limerick Seed to Plate

The aim of the project is to address an identified need in the community, promoting healthy eating and organic home-gardening practices. Building on the success of a pilot intergenerational project entitled "Through the Years", it became apparent that gardening related activities could be implemented and promoted on a larger scale, reaching the wider community, groups and classes. The project serves as a setting for community education and will be inclusive in helping reduce isolation by providing meeting places for all members of their local communities. Key people being targeted are older people, local families and residents, Limerick Youth Service, After School Clubs, the Garda Youth Diversion Project and the Family Resource Centre. The Limerick Seed to Plate works with gardeners whose primary focus is to develop the gardening projects further. There is a strong educational emphasis to the project and the learning is transferred to participants own homes and lifestyles. Southill has a community café and, where possible, food grown in their garden is showcased and cooked in the centre and café. The Community Food Initiative strengthens the existing healthy eating habits in the community and aims to result in increased long-term health benefits arising from a healthier lifestyle. Communities will benefit from the project which will create employment, build bridges between communities, promote social inclusion and provide a focus for the local areas. Part of theDemonstration Programme 2010-2012 Location Limerick Target Groups At risk youth Children ( 4-12 years) Children (0-4 years) Children (13-18 years) Families Lone parents Low income families Men Migrant, minority ethnic groups Older people Travellers Unemployed Women

Three new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from the lesser seed-finch, Oryzoborus angolensis (Passeriformes: Emberizidae) from Brazil

Three new coccidian (Apicomplexa: Eimeriidae) species are reported from the lesser seed-finch, Oryzoborus angolensis from Brazil. Sporulated oocysts of Isospora curio n. sp. are spherical to subspherical; 24.6 × 23.6 (22-26 × 22-25) mum, shape-index (SI, length/width) of 1.04 (1.00-1.15). Oocyst wall is bilayerd, ~ 1.5 mum thick, smooth and colourless. Micropyle and oocyst residuum are absent. The sporocysts are ovoid, 13.2 × 10.9 (15-17 × 10-13) mum, SI = 1.56 (1.42-1.71), with a small Stieda body and residuum composed of numerous granules scattered among the sporozoites. Sporozoites are elongated and posses a smooth surface and two distinct refractile bodies. Oocysts of Isospora braziliensis n. sp. are spherical to subspherical, 17.8 × 16.9 (16-19 × 16-18) mum, with a shape-index of 1.06 (1.00-1.12) and a smooth, single-layered wall ~ 1 mum thick. A micropyle, oocyst residuum and polar granules are absent. Sporocysts are ellipsoid and slightly asymmetric, 13.2 × 10.8 (12-14 × 9-12) mum, SI = 1.48 (1.34-1.61). Each sporocyst contains a barely visible Stieda body and a residuum composed numerous of granules. Sporozoites are elongated and each of them contains two distinct refractile bodies. Oocysts of Isospora paranaensis n. sp. are subspherical to broadly ellipsoid 24.3 × 19.8 (22-26 × 18-22) mum, SI = 1.22 (1.15-1.38) with smooth single-layered wall ~ 1.5 mum thick. A micropyle and oocyst residuum are absent, but one distinct ellipsoid polar granule (2.5-3.5 × 1.5-2.5 mum) is present. Sporocyst are ovoid, 15.7 × 10.1 (14-18 × 8-12) mum, SI = 1.46 (1.31-1.72), with distinct Stieda and sub-Stieda bodies. Each sporocyst contains a spherical sporocyst residuum, 4 mum in diameter. All described isosporan species represent a possible cause of acute coccidiosis for O. angolensis in captivity.

Role of the microenvironment on epithelial stem cell fate

Stratified epithelia of mammals contain adult stem/progenitor cells that are instrumental for renewal, regeneration and repair. We have recently demonstrated, using clonal and functional analysis, that all stratified epithelia contain clonogenic stem cells that can respond to skin morphogenetic signals, while cells obtained from simple or pseudo-stratified epithelia cannot. A genome-wide expression analysis favors multilineage priming rather than reprogramming. Collectively, these observations are reminiscent of epithelial metaplasia, a phenomenon in which a cell adopts the phenotype of another epithelial cell, often in response to repeated environmental stress, e.g. smoking, alcohol and micro-traumatisms. Furthermore, they support the notion that metaplasia results from the expression of an unseen potency, revealed by an environmental deficiency. The thymus supposedly contains only progenitor epithelial cells but no stem cells. We have demonstrated that the thymus also contains a small population of clonogenic cells that can function as bona fide multipotent hair follicle stem cells in response to an inductive skin microenvironment and a genome-wide expression analysis indicates that it correlates with robust changes in the expression of genes important for thymus identity. Hence, multilineage priming or reprogramming can account for the fate change of epithelial stem/progenitor cells in response to a varying microenvironment.

Predicting spatial patterns of plant biodiversity : from species to communities

Understanding the distribution and composition of species assemblages and being able to predict them in space and time are highly important tasks io investigate the fate of biodiversity in the current global changes context. Species distribution models are tools that have proven useful to predict the potential distribution of species by relating their occurrences to environmental variables. Species assemblages can then be predicted by combining the prediction of individual species models. In the first part of my thesis, I tested the importance of new environmental predictors to improve species distribution prediction. I showed that edaphic variables, above all soil pH and nitrogen content could be important in species distribution models. In a second chapter, I tested the influence of different resolution of predictors on the predictive ability of species distribution models. I showed that fine resolution predictors could ameliorate the models for some species by giving a better estimation of the micro-topographic condition that species tolerate, but that fine resolution predictors for climatic factors still need to be ameliorated. The second goal of my thesis was to test the ability of empirical models to predict species assemblages' characteristics such as species richness or functional attributes. I showed that species richness could be modelled efficiently and that the resulting prediction gave a more realistic estimate of the number of species than when obtaining it by stacking outputs of single species distribution models. Regarding the prediction of functional characteristics (plant height, leaf surface, seed mass) of plant assemblages, mean and extreme values of functional traits were better predictable than indices reflecting the diversity of traits in the community. This approach proved interesting to understand which environmental conditions influence particular aspects of the vegetation functioning. It could also be useful to predict climate change impacts on the vegetation. In the last part of my thesis, I studied the capacity of stacked species distribution models to predict the plant assemblages. I showed that this method tended to over-predict the number of species and that the composition of the community was not predicted exactly either. Finally, I combined the results of macro- ecological models obtained in the preceding chapters with stacked species distribution models and showed that this approach reduced significantly the number of species predicted and that the prediction of the composition is also ameliorated in some cases. These results showed that this method is promising. It needs now to be tested on further data sets. - Comprendre la manière dont les plantes se répartissent dans l'environnement et s'organisent en communauté est une question primordiale dans le contexte actuel de changements globaux. Cette connaissance peut nous aider à sauvegarder la diversité des espèces et les écosystèmes. Des méthodes statistiques nous permettent de prédire la distribution des espèces de plantes dans l'espace géographique et dans le temps. Ces modèles de distribution d'espèces, relient les occurrences d'une espèce avec des variables environnementales pour décrire sa distribution potentielle. Cette méthode a fait ses preuves pour ce qui est de la prédiction d'espèces individuelles. Plus récemment plusieurs tentatives de cumul de modèles d'espèces individuelles ont été réalisées afin de prédire la composition des communautés végétales. Le premier objectif de mon travail est d'améliorer les modèles de distribution en testant l'importance de nouvelles variables prédictives. Parmi différentes variables édaphiques, le pH et la teneur en azote du sol se sont avérés des facteurs non négligeables pour prédire la distribution des plantes. Je démontre aussi dans un second chapitre que les prédicteurs environnementaux à fine résolution permettent de refléter les conditions micro-topographiques subies par les plantes mais qu'ils doivent encore être améliorés avant de pouvoir être employés de manière efficace dans les modèles. Le deuxième objectif de ce travail consistait à étudier le développement de modèles prédictifs pour des attributs des communautés végétales tels que, par exemple, la richesse en espèces rencontrée à chaque point. Je démontre qu'il est possible de prédire par ce biais des valeurs de richesse spécifiques plus réalistes qu'en sommant les prédictions obtenues précédemment pour des espèces individuelles. J'ai également prédit dans l'espace et dans le temps des caractéristiques de la végétation telles que sa hauteur moyenne, minimale et maximale. Cette approche peut être utile pour comprendre quels facteurs environnementaux promeuvent différents types de végétation ainsi que pour évaluer les changements à attendre au niveau de la végétation dans le futur sous différents régimes de changements climatiques. Dans une troisième partie de ma thèse, j'ai exploré la possibilité de prédire les assemblages de plantes premièrement en cumulant les prédictions obtenues à partir de modèles individuels pour chaque espèce. Cette méthode a le défaut de prédire trop d'espèces par rapport à ce qui est observé en réalité. J'ai finalement employé le modèle de richesse en espèce développé précédemment pour contraindre les résultats du modèle d'assemblage de plantes. Cela a permis l'amélioration des modèles en réduisant la sur-prédiction et en améliorant la prédiction de la composition en espèces. Cette méthode semble prometteuse mais de nouveaux tests sont nécessaires pour bien évaluer ses capacités.

Control of hair follicle cell fate by underlying mesenchyme through a CSL-Wnt5a-FoxN1 regulatory axis.

Epithelial-mesenchymal interactions are key to skin morphogenesis and homeostasis. We report that maintenance of the hair follicle keratinocyte cell fate is defective in mice with mesenchymal deletion of the CSL/RBP-Jkappa gene, the effector of "canonical" Notch signaling. Hair follicle reconstitution assays demonstrate that this can be attributed to an intrinsic defect of dermal papilla cells. Similar consequences on hair follicle differentiation result from deletion of Wnt5a, a specific dermal papilla signature gene that we found to be under direct Notch/CSL control in these cells. Functional rescue experiments establish Wnt5a as an essential downstream mediator of Notch-CSL signaling, impinging on expression in the keratinocyte compartment of FoxN1, a gene with a key hair follicle regulatory function. Thus, Notch/CSL signaling plays a unique function in control of hair follicle differentiation by the underlying mesenchyme, with Wnt5a signaling and FoxN1 as mediators.

Perimicrovillar membrane assembly: the fate of phospholipids synthesised by the midgut of Rhodnius prolixus

In this study, we describe the fate of fatty acids that are incorporated from the lumen by the posterior midgut epithelium of Rhodnius prolixus and the biosynthesis of lipids. We also demonstrate that neutral lipids (NL) are transferred to the haemolymphatic lipophorin (Lp) and that phospholipids remain in the tissue in which they are organised into perimicrovillar membranes (PMMs). 3H-palmitic acid added at the luminal side of isolated midguts of R. prolixus females was readily absorbed and was used to synthesise phospholipids (80%) and NL (20%). The highest incorporation of 3H-palmitic acid was on the first day after a blood meal. The amounts of diacylglycerol (DG) and triacylglycerol synthesised by the tissue decreased in the presence of Lp in the incubation medium. The metabolic fates of 3H-lipids synthesised by the posterior midgut were followed and it was observed that DG was the major lipid released to Lp particles. However, the majority of phospholipids were not transferred to Lp, but remained in the tissue. The phospholipids that were synthesised and accumulated in the posterior midgut were found to be associated with Rhodnius luminal contents as structural components of PMMs.