1,001 research outputs found

    The effects of sex-biased gene expression and X-linkage on rates of sequence evolution in Drosophila

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    A faster rate of adaptive evolution of X-linked genes compared with autosomal genes (the faster-X effect) can be caused by the fixation of recessive or partially recessive advantageous mutations. This effect should be largest for advantageous mutations that affect only male fitness, and least for mutations that affect only female fitness. We tested these predictions in Drosophila melanogaster by using coding and functionally significant noncoding sequences of genes with different levels of sex-biased expression. Consistent with theory, nonsynonymous substitutions in most male-biased and unbiased genes show faster adaptive evolution on the X. However, genes with very low recombination rates do not show such an effect, possibly as a consequence of Hill–Robertson interference. Contrary to expectation, there was a substantial faster-X effect for female-biased genes. After correcting for recombination rate differences, however, female-biased genes did not show a faster X-effect. Similar analyses of noncoding UTRs and long introns showed a faster-X effect for all groups of genes, other than introns of female-biased genes. Given the strong evidence that deleterious mutations are mostly recessive or partially recessive, we would expect a slower rate of evolution of X-linked genes for slightly deleterious mutations that become fixed by genetic drift. Surprisingly, we found little evidence for this after correcting for recombination rate, implying that weakly deleterious mutations are mostly close to being semidominant. This is consistent with evidence from polymorphism data, which we use to test how models of selection that assume semidominance with no sex-specific fitness effects may bias estimates of purifying selection

    Social and spatial equity effects of non-motorised accessibility to retail

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    The evaluation of social and spatial effects of how accessibility is distributed between individuals is key to studying equity issues in transportation. However, the establishment of minimum accessibility requirements and the identification of accessibility thresholds for population groups remain as key methodological barriers. This paper contributes to addressing these shortcomings by using Retail Mobility Environments as an analytical and geographical concept to identify advantageous and disadvantageous non-motorised accessibility to retail for different population groups. The city of Zaragoza, Spain provides the spatial laboratory for experimentation, and the study focuses on four target groups: the young employed, the young unemployed, seniors, and adults. The results reveal social and spatial inequalities in the distribution of non-motorised accessibility in Zaragoza, with marked negative effects on the young unemployed and adults. On the other hand, seniors and the young employed are the groups that benefit from the current setup. It is finally discussed on the capacity of the proposed methodology for exploring both social and spatial inequalities, for establishing minimum accessibility requirements, and for identifying accessibility thresholds according to different population groups. Furthermore, the convenience of linking equity issues to non-motorised accessibility is also highlighted

    Detection by ELISA of predators of Prays oleae (Lepidoptera: Plutellidae) in a portuguese olive orchard

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    Over 900 predators were collected during two years from a Portuguese organic olive orchard, and tested in a serological bioassay for Prays oleae predation. The highest number of predators tested positive during the phyllophagous and antophagous generations of P. oleae. Ants were the most commonly found predators, followed by Coleoptera, Hemiptera and spiders

    Effects of no tillage on the abundance and diversity of soil and olive tree canopy arthropods.

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    Soil tillage is a traditional practice in the olive groves of TrĂĄs-os-Montes region (Northeast of Portugal) where the soil is maintained without any vegetal cover. However, this agronomic practice may have dangerous environmental effects of several orders. In this way, with the present work we aimed to contribute for the knowledge about the effect of two soil management practices in the olive grove (traditional tillage in comparison to no tillage) on the arthropods abundance and diversity of the olive grove soil and the olive tree canopy with special reference to Formicidae family. The work was developed between April and October of 2004, in two continuous plots submitted to the following agronomical practices: one plot submitted to frequent tillage to control weeds, and the other plot was no tilled. Monthly, the soil fauna was evaluated by 30 pitfall traps and olive canopy fauna was monitored by the beating technique of 25 trees per plot. The recovered material was sorted and identified. The results showed the existence of a diverse and rich fauna associated to the soil of olive grove and olive tree canopy. The olive soil arthropods are constituted mainly by Formicidae and Collembola

    Estudo preliminar sobre as formigas (Hymenoptera: Formicidae) associadas ao olival da Terra Quente Transmontana (Nordeste de Portugal).

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    Com o presente estudo pretendeu-se contribuir para identificar as principais espĂ©cies de formigas associadas ao olival da Terra Quente Transmontana (Nordeste de Portugal) e por outro lado, conhecer diferentes aspectos do seu comportamento, como os que se referem Ă  Ă©poca de maior ocorrĂȘncia das diferentes espĂ©cies, ao perĂ­odo do dia em que apresentam maior actividade nas ĂĄrvores e Ă  sua importĂąncia na protecção contra espĂ©cies nocivas. As observaçÔes decorreram entre Abril e Junho de 1999, num olival de cerca de 50 anos de idade, isento de tratamentos fitossanitĂĄrios hĂĄ vĂĄrios anos e conduzido em regime de sequeiro. Com periodicidade semanal seleccionaram-se ao acaso trĂȘs ĂĄrvores, cujo tronco se observou durante 10 minutos em quatro perĂ­odos distintos do dia - 9, 11, 15 e 17 horas -, para recolha de todas as formigas presentes. Estas identificaram-se como pertencentes a dez espĂ©cies: Crematogaster scutellaris Oliv., Tapinoma nigerrimwn Nyl., Tetramorium semilaeve AndrĂ©, Cataglyphis hispĂąnica Emery, C. ibĂ©rica Emery, Camponotus piceus Leach, C. lateralis Oliv., C.foreli Emery, Leptothorax angustulus Nyl. e Plagiolepis pygmaea (Latr.). T. nigerrimum foi a espĂ©cie mais abundante, quer no conjunto dos exemplares identificados, com 89,4% destes exemplares, quer em cada uma das datas de amostragem e perĂ­odos do dia. A maior actividade registou-se nas amostragens correspondentes Ă s 9 e 17 horas, quando se obtiveram 30,7% e 30,2% do total de exemplares. Nove dos indivĂ­duos recolhidos transportavam presas visĂ­veis, que eram, em seis casos, lagartas de Prays oleae (Bern.), num caso um adulto de Euphyllura olivina Costa e noutro, uma ninfa de Psocoptera e um indivĂ­duo nĂŁo identificado. Das formigas que transportavam presas, trĂȘs pertenciam Ă  espĂ©cie T. nigerrimum, trĂȘs a C. piceus, duas a C. hispĂąnica e uma a C. scutellaris

    Tomato Response to Fusarium spp. Infection under Field Conditions: Study of Potential Genes Involved

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    Tomato is one of the most important horticultural crops in the world and is severely affected by Fusarium diseases. To successfully manage these diseases, new insights on the expression of plant– pathogen interaction genes involved in immunity responses to Fusarium spp. infection are required. The aim of this study was to assess the level of infection of Fusarium spp. in field tomato samples and to evaluate the differential expression of target genes involved in plant–pathogen interactions in groups presenting different infection levels. Our study was able to detect Fusarium spp. in 16 from a total of 20 samples, proving the effectiveness of the primer set designed in the ITS region for its detection, and allowed the identification of two main different species complexes: Fusarium oxysporum and Fusarium incarnatum-equiseti. Results demonstrated that the level of infection positively influenced the expression of the transcription factor WRKY41 and the CBEF (calcium-binding EF hand family protein) genes, involved in plant innate resistance to pathogens. To the best of our knowledge, this is the first time that the expression of tomato defense-related gene expression is studied in response to Fusarium infection under natural field conditions. We highlight the importance of these studies for the identification of candidate genes to incorporate new sources of resistance in tomato and achieve sustainable plant disease management.This research was supported by projects “Development of a new virus-based vector to control TSWV in tomato plants” with the references ALT20-03-0145-FEDER-028266 and PTDC/ASP-PLA/28266/2017, and “Control of olive anthracnose through gene silencing and gene ex- pression using a plant virus vector” with the references ALT20-03-0145-FEDER-028263 and PTDC/ASP- PLA/28263/2017, both projects co-financed by the European Union through the European Regional Development Fund, under the ALENTEJO 2020 (Regional Operational Program of the Alentejo), ALGARVE 2020 (Regional Operational Program of the Algarve) and through the Foundation for Science and Technology (FCT), in its national component. M.P. was supported by Portuguese National Funds through FCT/MCTES, under the PhD scholarship SFRH/BD/145321/2019, co-financed by the European Social Fund through the Regional Operational Program of the Alentejo. J.A.R. was supported by Portuguese National Funds through Project ALT20-03-0246-FEDER-000056, “BIOPRO- TOMATE: Bioproteção do tomateiro contra a fusariose—impacto das práticas agronómicas”, under scholarship BI_MESTRE_Uevora_CER_BIOPROTOMATE, co-financed by the European Regional Development Fund through Regional Operational Program Alentejo 2020

    Defense Strategies: The Role of Transcription Factors in Tomato–Pathogen Interaction

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    Tomato, one of the most cultivated and economically important vegetable crops throughout the world, is affected by a panoply of different pathogens that reduce yield and affect product quality. The study of tomato–pathogen system arises as an ideal system for better understanding the molecular mechanisms underlying disease resistance, offering an opportunity of improving yield and quality of the products. Among several genes already identified in tomato response to pathogens, we highlight those encoding the transcription factors (TFs). TFs act as transcriptional activators or repressors of gene expression and are involved in large-scale biological phenomena. They are key regulators of central components of plant innate immune system and basal defense in diverse biological processes, including defense responses to pathogens. Here, we present an overview of recent studies of tomato TFs regarding defense responses to biotic stresses. Hence, we focus on different families of TFs, selected for their abundance, importance, and availability of functionally well-characterized members in response to pathogen attack. Tomato TFs’ roles and possibilities related to their use for engineering pathogen resistance in tomato are presented. With this review, we intend to provide new insights into the regulation of tomato defense mechanisms against invading pathogens in view of plant breeding.This work was funded by the projects “Development of a new virus-based vector to control TSWV in tomato plants” with the references ALT20-03-0145-FEDER-028266 and PTDC/ASP-PLA/28266/2017, and “Control of olive anthracnose through gene silencing and gene expression using a plant virus vector” with the references ALT20-03-0145-FEDER-028263 and PTDC/ASP-PLA/28263/2017, co-financed by the European Union through the European Regional Development Fund, under the ALENTEJO 2020 (Regional Operational Program of the Alentejo), ALGARVE 2020 (Regional Operational Program of the Algarve) and through the Foundation for Science and Technology (FCT), in its national component. M.P. was supported by Portuguese National Funds through FCT/MCTES, under the PhD scholarship SFRH/BD/145321/2019, co-financed by the European Social Fund through the Regional Operational Program of the Alentejo. This work was also supported by National Funds through FCT under the Project UIDB/05183/2020

    Comparison of a proprioceptive training program on stable base and unstable base

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    El objetivo de este estudio fue comparar dos programas de entrenamiento propioceptivo sobre base estable (G1) y base inestable (G2). Durante 5 semanas, 18 jugadores de fĂștbol profesional se sometieron a un programa de entrenamiento propioceptivo, 9 formaron el G1 y 9 G2. Se aplicĂł el Standard Excursion Balance Test (Test de Estrella) antes y despuĂ©s de la intervenciĂłn. Los resultados intragrupo mostraron diferencias significativas en las variables ANT.IZDO; ANTLAT.IZDO; POST.D y ANTMED.D (p<0,005) para el G1 y ANT.D; ANT.IZDO; POSTMED.D; POSTMED.IZDO Y MED.D (p <0,005) para el G2. No se hallaron evidencias significativas entre el entrenamiento en base estable y base inestable para la mejora del equilibrio y la estabilidadThe aim is to compare two proprioceptive training programs on a stable (G1) and an unstable (G2) base in terms of balance and stability. During a 5 week period, 18 professional football players underwent a proprioceptive training program, 9 in G1 and the other 9 in G2. The Standard Excursion Balance Test was applied before and after the intervention program. Significant intragroup differences were found in the variables LEFT FRONT, ANTEROLATERAL LEFT (ANTLAT.LEFT), BACK RIGHT and ANTEROMEDIAL RIGHT (ANTMED.RIGHT) (p<0,005) for the G1, and FRONT RIGHT, FRONT LEFT, POSTMED.RIGHT, POSTMED.LEFT and MED.RIGHT (p <0,005) for G2. We conclude that there are no significant differences between the unstable base training and training stable base regarding improvement in balance and stabilit
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