Sodium-dependent phosphate transporters in osteoclast differentiation and function.

Osteoclasts are multinucleated bone degrading cells. Phosphate is an important constituent of mineralized bone and released in significant quantities during bone resorption. Molecular contributors to phosphate transport during the resorptive activity of osteoclasts have been controversially discussed. This study aimed at deciphering the role of sodium-dependent phosphate transporters during osteoclast differentiation and bone resorption. Our studies reveal RANKL-induced differential expression of sodium-dependent phosphate transport protein IIa (NaPi-IIa) transcript and protein during osteoclast development, but no expression of the closely related NaPi-IIb and NaPi-IIc SLC34 family isoforms. In vitro studies employing NaPi-IIa-deficient osteoclast precursors and mature osteoclasts reveal that NaPi-IIa is dispensable for bone resorption and osteoclast differentiation. These results are supported by the analysis of structural bone parameters by high-resolution microcomputed tomography that yielded no differences between adult NaPi-IIa WT and KO mice. By contrast, both type III sodium-dependent phosphate transporters Pit-1 and Pit-2 were abundantly expressed throughout osteoclast differentiation, indicating that they are the relevant sodium-dependent phosphate transporters in osteoclasts and osteoclast precursors. We conclude that phosphate transporters of the SLC34 family have no role in osteoclast differentiation and function and propose that Pit-dependent phosphate transport could be pivotal for bone resorption and should be addressed in further studies.

Adaptation of Root Function by Nutrient-Induced Plasticity of Endodermal Differentiation.

Plant roots forage the soil for minerals whose concentrations can be orders of magnitude away from those required for plant cell function. Selective uptake in multicellular organisms critically requires epithelia with extracellular diffusion barriers. In plants, such a barrier is provided by the endodermis and its Casparian strips-cell wall impregnations analogous to animal tight and adherens junctions. Interestingly, the endodermis undergoes secondary differentiation, becoming coated with hydrophobic suberin, presumably switching from an actively absorbing to a protective epithelium. Here, we show that suberization responds to a wide range of nutrient stresses, mediated by the stress hormones abscisic acid and ethylene. We reveal a striking ability of the root to not only regulate synthesis of suberin, but also selectively degrade it in response to ethylene. Finally, we demonstrate that changes in suberization constitute physiologically relevant, adaptive responses, pointing to a pivotal role of the endodermal membrane in nutrient homeostasis.

Mammalian Target of Rapamycin Complex 2 Controls CD8 T Cell Memory Differentiation in a Foxo1-Dependent Manner.

Upon infection, antigen-specific naive CD8 T cells are activated and differentiate into short-lived effector cells (SLECs) and memory precursor cells (MPECs). The underlying signaling pathways remain largely unresolved. We show that Rictor, the core component of mammalian target of rapamycin complex 2 (mTORC2), regulates SLEC and MPEC commitment. Rictor deficiency favors memory formation and increases IL-2 secretion capacity without dampening effector functions. Moreover, mTORC2-deficient memory T cells mount more potent recall responses. Enhanced memory formation in the absence of mTORC2 was associated with Eomes and Tcf-1 upregulation, repression of T-bet, enhanced mitochondrial spare respiratory capacity, and fatty acid oxidation. This transcriptional and metabolic reprogramming is mainly driven by nuclear stabilization of Foxo1. Silencing of Foxo1 reversed the increased MPEC differentiation and IL-2 production and led to an impaired recall response of Rictor KO memory T cells. Therefore, mTORC2 is a critical regulator of CD8 T cell differentiation and may be an important target for immunotherapy interventions.

Ancient DNA of the extinct Lava shearwater (Puffinus olsoni) from the Canary Islands reveals incipient differentiation within the P. puffinus complex

The loss of species during the Holocene was, dramatically more important on islands than on continents. Seabirds from islands are very vulnerable to human-induced alterations such as habitat destruction, hunting and exotic predators. For example, in the genus Puffinus (family Procellariidae) the extinction of at least five species has been recorded during the Holocene, two of them coming from the Canary Islands.

Phylogenetic relationships of the newly discovered sexual state of Talaromyces flavovirens, comb. nov.

Typical Talaromyces ascomata were observed on dry Quercus suber leaf litter amongst the characteristic synnemata of Penicillium aureocephalum, and they appear to represent the sexual state of the latter species. The species is a synonym of the older Lasioderma flavovirens, and we propose the new combination Talaromyces flavovirens. Lectotype and epitype specimens are designated for this name. The defining characters of the asexual state include yellow, short-stalked, mycetozoan-like synnemata with an unusual, almost closed terminal head of penicillate conidiophores intermixed with sinuous hyphae, and dark green conidia. Ascomata could not be induced in culture, but PCR amplifications of mating-type genes indicate the species is heterothallic. In nature, ascocarp initials appear to be antheridia coiled around clavate ascogonia, similar to those of T. flavus, and the thick-walled, spiny ascospores are also similar to those of T. flavus. ITS barcodes and β-tubulin sequences place T. flavovirens in a clade with T. apiculatus, T. flavus, T. funiculosus, T. galapagensis, T. pinophilus, T. macrosporus, and seven other species.

Avaluació del sistema de confusió sexual pel control de carpocapsa (Cydia pomonella L.) en plantacions de pomeres de Fructícola Empordà S.L. durant el període 2003-2011

La carpocapsa o corc de la poma (Cydia pomonella L.) és la plaga clau de lesplantacions comercials de pomera de la zona de Girona. Per controlar-la amb eficàcia,anualment són necessaris diferents tractaments insecticides que a més del cost econòmicque representen, afavoreixen fenòmens de resistències, aparició de plagues induïdes iproblemes de toxicitat, residus i contaminació ambiental.La combinació de diferents metodologies per combatre aquesta plaga, algunes menysagressives amb la fauna auxiliar i el medi ambient, s’ha convertit en una pràcticaimprescindible per aconseguir-ne un control efectiu i sostenible. La confusió sexual ésuna tècnica de lluita biotecnològica que per les seves característiques d’especificitat,toxicologia i respecte al medi ambient, representa una alternativa a la problemàticagenerada pels productes químics tradicionals.Fructícola Empordà S.L., empresa agroalimentària situada al municipi de Sant PerePescador (Alt Empordà, Girona) dedicada a la producció i comercialització de fruitafresca, com a entitat participant del projecte Àrea Pilot de Reducció d’Insecticides enplantacions comercials de pomera de Girona (APRI) emmarcat en el programad’actuacions específiques de les Associacions de Defensa dels Vegetals (ADV’s) de lazona, introdueix per primera vegada la tècnica de la confusió sexual a l’estratègia decontrol de carpocapsa en determinades parcel•les comercials on la lluita químicaexclusiva no és suficient (2003). Durant el període 2003-2011, l’ús de la confusió sexual per al control de carpocapsa esgeneralitza progressivament a les finques dels agricultors de Fructícola Empordà S.L.amb l’objectiu principal de reduir el percentatge de dany per atac de carpocapsa en elsfruits a collita i, conseqüentment, disminuir la pressió del corc de la poma a la zona. Atal efecte es va plantejar un estudi amb l’objectiu d’avaluar l’eficàcia de l’estratègia decontrol de la carpocapsa basada en la combinació del mètode de la confusió sexual ambaplicacions fitosanitàries de reforç durant el període d’expansió de la tècnica (2003-2011) en les plantacions comercials de pomera de Fructícola Empordà S.L. així com,fer una valoració d’aquest respecte al sistema de control paral•lelament utilitzat a lazona, la lluita química assessorada

Necesidades educativas para promover la salud afectiva y sexual en jóvenes en riesgo social

La educación afectiva y sexual de los y las jóvenes en situación de riesgo social es un elemento esencial para su salud. La educación en esta área requiere unos planteamientos rigurosos que se basen en las necesidades educativas y diferenciales de este colectivo en relación a la salud afectiva y sexual. El presente artículo presenta los resultados de una investigación que analiza estas necesidades. Para ello, se diseñó una investigación acción participativa de carácter cualitativa, en la cual participaron 48 profesionales y 72 jóvenes. La recogida de información se realizó mediante grupos de discusión. Los resultados constatan que el factor cultural y la historia personal y familiar son variables que tienen un carácter concluyente en los comportamientos sexuales de este colectivo. Estas variables deben considerarse, tanto en la educación formal como en la no formal, con tal de promover la salud afectiva sexual, haciendo especial hincapié en los aspectos emocionales, afectivos y sociales.

Educación en Valores y Diferencia Sexual: Realidad y políticas educativas en el contexto español

Este artículo analiza para el contexto español las políticas promovidas en los últimos años por el gobierno conservador del partido popular y los cambios que conllevaron la entrada en vigor, en el 2002, de la Ley de Calidad de la Enseñanza. Los mismos no parecen garantizar la igualdad de oportunidades para las mujeres, pues nos encontramos ante una Ley cuya finalidad es buscar respuestas a los cambios tecnológicos y los criterios de mercado, llegando a afirmarse que las reformas educativas son necesarias para la “revisión, ajuste y mejora”, siendo la “calidad” el mecanismo para “el logro de cotas más elevadas de progreso social y económico”. A pesar de que la exposición de motivos de la Ley alude al bienestar individual y social –sin explicitar abiertamente el significado que les otorga-, los planteamientos neoliberales de las economías capitalistas se insertan en el discurso y se habla, como se ha indicado, de la necesidad de ajustes que en estas perspectivas no garantizan el avance en la lucha contra la exclusión y la discriminación, dificultando el encuentro de las diferencias, de lo femenino y de lo masculino. El nuevo gobierno socialista, surgido de las elecciones celebradas en el pasado mes de marzo de 2004, forzosamente debe plantear una transición educativa que necesita de medidas urgentes, atrevidas y transformadoras.

A matter of scale: apparent niche differentiation of diploid and tetraploid plants may depend on extent and grain of analysis

Aim: Emerging polyploids may depend on environmental niche shifts for successful establishment. Using the alpine plant Ranunculus kuepferi as a model system, we explore the niche shift hypothesis at different spatial resolutions and in contrasting parts of the species range. Location: European Alps. Methods: We sampled 12 individuals from each of 102 populations of R. kuepferi across the Alps, determined their ploidy levels, derived coarse-grain (100x100m) environmental descriptors for all sampling sites by downscaling WorldClim maps, and calculated fine-scale environmental descriptors (2x2m) from indicator values of the vegetation accompanying the sampled individuals. Both coarse and fine-scale variables were further computed for 8239 vegetation plots from across the Alps. Subsequently, we compared niche optima and breadths of diploid and tetraploid cytotypes by combining principal components analysis and kernel smoothing procedures. Comparisons were done separately for coarse and fine-grain data sets and for sympatric, allopatric and the total set of populations. Results: All comparisons indicate that the niches of the two cytotypes differ in optima and/or breadths, but results vary in important details. The whole-range analysis suggests differentiation along the temperature gradient to be most important. However, sympatric comparisons indicate that this climatic shift was not a direct response to competition with diploid ancestors. Moreover, fine-grained analyses demonstrate niche contraction of tetraploids, especially in the sympatric range, that goes undetected with coarse-grained data. Main conclusions: Although the niche optima of the two cytotypes differ, separation along ecological gradients was probably less decisive for polyploid establishment than a shift towards facultative apomixis, a particularly effective strategy to avoid minority cytotype exclusion. In addition, our results suggest that coarse-grained analyses overestimate niche breadths of widely distributed taxa. Niche comparison analyses should hence be conducted at environmental data resolutions appropriate for the organism and question under study.

Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration.

The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.

Microscopy of Fission Yeast Sexual Lifecycle.

The fission yeast Schizosaccharomyces pombe has been an invaluable model system in studying the regulation of the mitotic cell cycle progression, the mechanics of cell division and cell polarity. Furthermore, classical experiments on its sexual reproduction have yielded results pivotal to current understanding of DNA recombination and meiosis. More recent analysis of fission yeast mating has raised interesting questions on extrinsic stimuli response mechanisms, polarized cell growth and cell-cell fusion. To study these topics in detail we have developed a simple protocol for microscopy of the entire sexual lifecycle. The method described here is easily adjusted to study specific mating stages. Briefly, after being grown to exponential phase in a nitrogen-rich medium, cell cultures are shifted to a nitrogen-deprived medium for periods of time suited to the stage of the sexual lifecycle that will be explored. Cells are then mounted on custom, easily built agarose pad chambers for imaging. This approach allows cells to be monitored from the onset of mating to the final formation of spores.