179 research outputs found

    Identifying and Characterizing Alternative Molecular Markers for the Symbiotic and Free-Living Dinoflagellate Genus Symbiodinium

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    Dinoflagellates in the genus Symbiodinium are best known as endosymbionts of corals and other invertebrate as well as protist hosts, but also exist free-living in coastal environments. Despite their importance in marine ecosystems, less than 10 loci have been used to explore phylogenetic relationships in this group, and only the multi-copy nuclear ribosomal Internal Transcribed Spacer (ITS) regions 1 and 2 have been used to characterize fine-scale genetic diversity within the nine clades (A–I) that comprise the genus. Here, we describe a three-step molecular approach focused on 1) identifying new candidate genes for phylogenetic analysis of Symbiodinium spp., 2) characterizing the phylogenetic relationship of these candidate genes from DNA samples spanning eight Symbiodinium clades (A–H), and 3) conducting in-depth phylogenetic analyses of candidate genes displaying genetic divergences equal or higher than those within the ITS-2 of Symbiodinium clade C. To this end, we used bioinformatics tools and reciprocal comparisons to identify homologous genes from 55,551 cDNA sequences representing two Symbiodinium and six additional dinoflagellate EST libraries. Of the 84 candidate genes identified, 7 Symbiodinium genes (elf2, coI, coIII, cob, calmodulin, rad24, and actin) were characterized by sequencing 23 DNA samples spanning eight Symbiodinium clades (A–H). Four genes displaying higher rates of genetic divergences than ITS-2 within clade C were selected for in-depth phylogenetic analyses, which revealed that calmodulin has limited taxonomic utility but that coI, rad24, and actin behave predictably with respect to Symbiodinium lineage C and are potential candidates as new markers for this group. The approach for targeting candidate genes described here can serve as a model for future studies aimed at identifying and testing new phylogenetically informative genes for taxa where transcriptomic and genomics data are available

    How victim age affects the context and timing of child sexual abuse: applying the routine activities approach to the first sexual abuse incident

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    The aim of this study was to examine from the routine activities approach how victim age might help to explain the timing, context and nature of offenders’ first known contact sexual abuse incident. One-hundred adult male child sexual abusers (M = 45.8 years, SD = 12.2; range = 20–84) were surveyed about the first time they had sexual contact with a child. Afternoon and early evening (between 3 pm and 9 pm) was the most common time in which sexual contact first occurred. Most incidents occurred in a home. Two-thirds of incidents occurred when another person was in close proximity, usually elsewhere in the home. Older victims were more likely to be sexually abused by someone outside their families and in the later hours of the day compared to younger victims. Proximity of another person (adult and/or child) appeared to have little effect on offenders’ decisions to abuse, although it had some impact on the level of intrusion and duration of these incidents. Overall, the findings lend support to the application of the routine activities approach for considering how contextual risk factors (i.e., the timing and relationship context) change as children age, and raise questions about how to best conceptualize guardianship in the context of child sexual abuse. These factors should be key considerations when devising and implementing sexual abuse prevention strategies and for informing theory development

    Microbial contributions to the persistence of coral reefs

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    On contemplating the adaptive capacity of reef organisms to a rapidly changing environment, the microbiome offers significant and greatly unrecognised potential. Microbial symbionts contribute to the physiology, development, immunity and behaviour of their hosts, and can respond very rapidly to changing environmental conditions, providing a powerful mechanism for acclimatisation and also possibly rapid evolution of coral reef holobionts. Environmentally acquired fluctuations in the microbiome can have significant functional consequences for the holobiont phenotype upon which selection can act. Environmentally induced changes in microbial abundance may be analogous to host gene duplication, symbiont switching / shuffling as a result of environmental change can either remove or introduce raw genetic material into the holobiont; and horizontal gene transfer can facilitate rapid evolution within microbial strains. Vertical transmission of symbionts is a key feature of many reef holobionts and this would enable environmentally acquired microbial traits to be faithfully passed to future generations, ultimately facilitating microbiome-mediated transgenerational acclimatisation (MMTA) and potentially even adaptation of reef species in a rapidly changing climate. In this commentary, we highlight the capacity and mechanisms for MMTA in reef species, propose a modified Price equation as a framework for assessing MMTA and recommend future areas of research to better understand how microorganisms contribute to the transgenerational acclimatisation of reef organisms, which is essential if we are to reliably predict the consequences of global change for reef ecosystems

    New Insights into the Evolution of Metazoan Tyrosinase Gene Family

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    Tyrosinases, widely distributed among animals, plants and fungi, are involved in the biosynthesis of melanin, a pigment that has been exploited, in the course of evolution, to serve different functions. We conducted a deep evolutionary analysis of tyrosinase family amongst metazoa, thanks to the availability of new sequenced genomes, assessing that tyrosinases (tyr) represent a distinctive feature of all the organisms included in our study and, interestingly, they show an independent expansion in most of the analyzed phyla. Tyrosinase-related proteins (tyrp), which derive from tyr but show distinct key residues in the catalytic domain, constitute an invention of chordate lineage. In addition we here reported a detailed study of the expression territories of the ascidian Ciona intestinalis tyr and tyrps. Furthermore, we put efforts in the identification of the regulatory sequences responsible for their expression in pigment cell lineage. Collectively, the results reported here enlarge our knowledge about the tyrosinase gene family as valuable resource for understanding the genetic components involved in pigment cells evolution and development

    Specialized interfaces of Smc5/6 control hinge stability and DNA association

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    The Structural Maintenance of Chromosomes (SMC) complexes: cohesin, condensin and Smc5/6 are involved in the organization of higher-order chromosome structure—which is essential for accurate chromosome duplication and segregation. Each complex is scaffolded by a specific SMC protein dimer (heterodimer in eukaryotes) held together via their hinge domains. Here we show that the Smc5/6-hinge, like those of cohesin and condensin, also forms a toroidal structure but with distinctive subunit interfaces absent from the other SMC complexes; an unusual ‘molecular latch’ and a functional ‘hub’. Defined mutations in these interfaces cause severe phenotypic effects with sensitivity to DNA-damaging agents in fission yeast and reduced viability in human cells. We show that the Smc5/6-hinge complex binds preferentially to ssDNA and that this interaction is affected by both ‘latch’ and ‘hub’ mutations, suggesting a key role for these unique features in controlling DNA association by the Smc5/6 complex

    Capital social en áreas rurales: adaptación al español y validación factorial de una escala

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    El capital social se considera un determinante estructural de desarrollo y bienestar social. Su componente cognitivo evalúa el grado de confianza de la población en sus sistemas de organización social, así como las interacciones comunitarias que estructuran respuestas sociales a los problemas sociales. Existen pocas escalas disponibles para la medición de este constructo. Este trabajo presenta los resultados de la adaptación al español y validación psicométrica de una escala para la medición de capital social en contextos rurales. Se adaptó al español la escala de capital social cognitivo de Wang. Se aplicaron 1200 cuestionarios a adultos en 12 veredas de Tierralta (Colombia) seleccionados con muestreo aleatorio simple estratificado. Se realizó análisis factorial de la escala a partir de una matriz de correlación policórica. El análisis factorial exploratorio sugiere la existencia de dos factores principales distribuidos así: 7 ítems para el factor 1 (confianza) (valor propio 3.23.) y 2 ítems para el factor 2 (desconfianza) (valor propio 1.40). Como fue observado por Wang, Q9 y Q10 parecen preguntas ambiguas que no aportan suficiente a ninguno de los factores. Se presenta la primera validación factorial al español de la escala de capital social de Wang en el contexto social de la Colombia rural

    The Diversification of the LIM Superclass at the Base of the Metazoa Increased Subcellular Complexity and Promoted Multicellular Specialization

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    Background: Throughout evolution, the LIM domain has been deployed in many different domain configurations, which has led to the formation of a large and distinct group of proteins. LIM proteins are involved in relaying stimuli received at the cell surface to the nucleus in order to regulate cell structure, motility, and division. Despite their fundamental roles in cellular processes and human disease, little is known about the evolution of the LIM superclass. Results: We have identified and characterized all known LIM domain-containing proteins in six metazoans and three nonmetazoans. In addition, we performed a phylogenetic analysis on all LIM domains and, in the process, have identified a number of novel non-LIM domains and motifs in each of these proteins. Based on these results, we have formalized a classification system for LIM proteins, provided reasonable timing for class and family origin events; and identified lineagespecific loss events. Our analysis is the first detailed description of the full set of LIM proteins from the non-bilaterian species examined in this study. Conclusion: Six of the 14 LIM classes originated in the stem lineage of the Metazoa. The expansion of the LIM superclass at the base of the Metazoa undoubtedly contributed to the increase in subcellular complexity required for the transition from a unicellular to multicellular lifestyle and, as such, was a critically important event in the history of animal multicellularity

    Inspiring and Advancing the Many-Disciplined Study of Institutional Trust

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    The purpose of this volume is to consider how trust research, particularly trust in institutions, might benefit from increased inter- or transdisciplinarity. In this introductory chapter, we first give some background on prior disciplinary, multidisciplinary, and interdisciplinary work relating to trust. Next, we describe how this manydisciplined volume on institutional trust emerged from the joint activities of the Nebraska Symposium on Motivation and a National Science Foundation-funded Workshop on institutional trust. This chapter describes some of the themes that emerged, while also providing an overview of the rest of the volume, which includes chapters that discuss conceptualizations, definitions, and measurement of trust; institutional trust across domains and contexts; and theoretical advances regarding the “dark” and “light” sides of institutional trust. Finally, we conclude with some thoughts about the future of and potential promises and pitfalls of trust as a focus of interdisciplinary study
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