11,423 research outputs found

    ENABLING EFFICIENT FLEET COMPOSITION SELECTION THROUGH THE DEVELOPMENT OF A RANK HEURISTIC FOR A BRANCH AND BOUND METHOD

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    In the foreseeable future, autonomous mobile robots (AMRs) will become a key enabler for increasing productivity and flexibility in material handling in warehousing facilities, distribution centers and manufacturing systems. The objective of this research is to develop and validate parametric models of AMRs, develop ranking heuristic using a physics-based algorithm within the framework of the Branch and Bound method, integrate the ranking algorithm into a Fleet Composition Optimization (FCO) tool, and finally conduct simulations under various scenarios to verify the suitability and robustness of the developed tool in a factory equipped with AMRs. Kinematic-based equations are used for computing both energy and time consumption. Multivariate linear regression, a data-driven method, is used for designing the ranking heuristic. The results indicate that the unique physical structures and parameters of each robot are the main factors contributing to differences in energy and time consumption. improvement on reducing computation time was achieved by comparing heuristic-based search and non-heuristic-based search. This research is expected to significantly improve the current nested fleet composition optimization tool by reducing computation time without sacrificing optimality. From a practical perspective, greater efficiency in reducing energy and time costs can be achieved.Ford Motor CompanyNo embargoAcademic Major: Aerospace Engineerin

    Norsk rÄ kumelk, en kilde til zoonotiske patogener?

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    The worldwide emerging trend of eating “natural” foods, that has not been processed, also applies for beverages. According to Norwegian legislation, all milk must be pasteurized before commercial sale but drinking milk that has not been heat-treated, is gaining increasing popularity. Scientist are warning against this trend and highlights the risk of contracting disease from milkborne microorganisms. To examine potential risks associated with drinking unpasteurized milk in Norway, milk- and environmental samples were collected from dairy farms located in south-east of Norway. The samples were analyzed for the presence of specific zoonotic pathogens; Listeria monocytogenes, Campylobacter spp., and Shiga toxin-producing Escherichia coli (STEC). Cattle are known to be healthy carriers of these pathogens, and Campylobacter spp. and STEC have a low infectious dose, meaning that infection can be established by ingesting a low number of bacterial cells. L. monocytogenes causes one of the most severe foodborne zoonotic diseases, listeriosis, that has a high fatality rate. All three pathogens have caused milk borne disease outbreaks all over the world, also in Norway. During this work, we observed that the prevalence of the three examined bacteria were high in the environment at the examined farms. In addition, 7% of the milk filters were contaminated by STEC, 13% by L. monocytogenes and 4% by Campylobacter spp. Four of the STEC isolates detected were eaepositive, which is associated with the capability to cause severe human disease. One of the eae-positive STEC isolates were collected from a milk filter, which strongly indicate that Norwegian raw milk may contain potential pathogenic STEC. To further assess the possibilities of getting ill by STEC after consuming raw milk, we examined the growth of the four eae-positive STEC isolates in raw milk at different temperatures. All four isolates seemed to have ability to multiply in raw milk at 8°C, and one isolate had significant growth after 72 hours. Incubation at 6°C seemed to reduce the number of bacteria during the first 24 hours before cell death stopped. These findings highlight the importance of stable refrigerator temperatures, preferable < 4°C, for storage of raw milk. The L. monocytogenes isolates collected during this study show genetic similarities to isolates collected from urban and rural environmental locations, but different clones were predominant in agricultural environments compared to clinical and food environments. However, the results indicate that the same clone can persist in a farm over time, and that milk can be contaminated by L. monocytogenes clones present in farm environment. Despite testing small volumes (25 mL) of milk, we were able to isolate both STEC and Campylobacter spp. directly from raw milk. A proportion of 3% of the bulk tank milk and teat milk samples were contaminated by Campylobacter spp. and one STEC was isolated from bulk tank milk. L monocytogenes was not detected in bulk tank milk, nor in teat milk samples. The agricultural evolvement during the past decades have led to larger production units and new food safety challenges. Dairy cattle production in Norway is in a current transition from tie-stall housing with conventional pipeline milking systems, to modern loose housing systems with robotic milking. The occurrence of the three pathogens in this project were higher in samples collected from farms with loose housing compared to those with tiestall housing. Pasteurization of cow’s milk is a risk reducing procedure to protect consumers from microbial pathogens and in most EU countries, commercial distribution of unpasteurized milk is legally restricted. Together, the results presented in this thesis show that the animal housing may influence the level of pathogenic bacteria in the raw milk and that ingestion of Norwegian raw cow’s milk may expose consumers to pathogenic bacteria which can cause severe disease, especially in children, elderly and in persons with underlying diseases. The results also highlight the importance of storing raw milk at low temperatures between milking and consumption.Å spise mat som er mindre prosessert og mer «naturlig» er en pĂ„gĂ„ende trend i Norge og i andre deler av verden. Interessen for Ă„ drikke melk som ikke er varmebehandlet, sĂ„kalt rĂ„ melk, er ogsĂ„ Ăžkende. I Norge er det pĂ„budt Ă„ pasteurisere melk fĂžr kommersielt salg for Ă„ beskytte forbrukeren mot sykdomsfremkallende mikroorganismer. Fagfolk advarer mot Ă„ drikke rĂ„ melk, og pĂ„peker risikoen for Ă„ bli syk av patogene bakterier som kan finnes i melken. I denne avhandlingen undersĂžker vi den potensielle risikoen det medfĂžrer Ă„ drikke upasteurisert melk fra Norge. I tillegg til Ă„ samle inn tankmelk- og speneprĂžver fra melkegĂ„rder i sĂžrĂžst Norge, samlet vi ogsĂ„ miljĂžprĂžver fra de samme gĂ„rdene for Ă„ kartlegge forekomst og for Ă„ identifisere potensielle mattrygghetsrisikoer i melkeproduksjonen. Alle prĂžvene ble analysert for de zoonotiske sykdomsfremkallende bakteriene Listeria monocytogenes, Campylobacter spp., og Shiga toksin-produserende Escherichia coli (STEC). Kyr kan vĂŠre friske smittebĂŠrere av disse bakteriene, som dermed kan etablere et reservoar pĂ„ gĂ„rdene. Bakteriene kan overfĂžres fra gĂ„rdsmiljĂžet til melkekjeden og dermed utfordre mattryggheten. Disse bakteriene har forĂ„rsaket melkebĂ„rne sykdomsutbrudd over hele verden, ogsĂ„ i Norge. Campylobacter spp. og STEC har lav infeksiĂžs dose, som vil si at man kan bli syk selv om man bare inntar et lavt antall bakterieceller. L. monocytogenes kan gi sykdommen listeriose, en av de mest alvorlige matbĂ„rne zoonotiske sykdommene vi har i den vestlige verden. Resultater fra denne oppgaven viser en hĂžy forekomst av de tre patogenene i gĂ„rdsmiljĂžet. I tillegg var 7% av melkefiltrene vi testet positive for STEC, 13% positive for L. monocytogenes og 4% positive for Campylobacter spp.. Fire av STEC isolatene bar genet for Intimin, eae, som er ansett som en viktig virulensfaktor som Ăžker sjansen for alvorlig sykdom. Ett av de eae-positive isolatene ble funnet i et melkefilter, noe som indikerer at norsk rĂ„ melk kan inneholde patogene STEC. For Ă„ videre vurdere risikoen for Ă„ bli syk av STEC fra rĂ„ melk undersĂžkte vi hvordan de fire eae-positive isolatene vokste i rĂ„ melk lagret ved forskjellige temperaturer. For alle isolatene Ăžkte antall bakterier etter lagring ved 8°C, og for et isolat var veksten signifikant. Etter lagring ved 6°C ble antallet bakterier redusert de fĂžrste 24 timene, deretter stoppet reduksjonen i antall bakterier. Disse resultatene viser hvor viktig det er Ă„ ha stabil lav lagringstemperatur for rĂ„ melk, helst < 4°C. L. monocytogenes isolatene som ble samlet inn fra melkegĂ„rdene viste genetiske likheter med isolater samlet inn fra urbane og rurale miljĂžer rundt omkring i Norge. Derimot var kloner som dominerte i landbruksmiljĂžet forskjellige fra kliniske isolater og isolater fra matproduksjonslokaler. Videre sĂ„ man at en klone kan persistere pĂ„ en gĂ„rd over tid og at melk kan kontamineres av L. monocytogenes kloner som er til stede i gĂ„rdsmiljĂžet. Til tross for smĂ„ testvolum av tankmelken (25 mL) fant vi bĂ„de STEC og Campylobacter spp. i melkeprĂžvene. 3% av tankmelkprĂžvene og speneprĂžvene var positive for Campylobacter spp. og ett STEC isolat ble funnet i tankmelk. L. monocytogenes ble ikke funnet direkte i melkeprĂžvene. Landbruket i Norge er i stadig utvikling der besetningene blir stĂžrre, men fĂŠrre. Melkebesetningene er midt i en overgang der tradisjonell oppstalling med melking pĂ„ bĂ„s byttes ut med lĂžsdriftssystemer og melkeroboter. Forekomsten av de tre patogenene funnet i denne studien var hĂžyere i besetningene med lĂžsdrift sammenliknet med besetningene som hadde melkekyrne oppstallet pĂ„ bĂ„s. Pasteurisering er et viktig forebyggende tiltak for Ă„ beskytte konsumenter fra mikrobielle patogener, og i de fleste EU-land er kommersielt salg av rĂ„ melk juridisk begrenset. Denne studien viser at oppstallingstype kan pĂ„virke nivĂ„ene av patogene bakterier i gĂ„rdsmiljĂžet og i rĂ„ melk. Inntak av rĂ„ melk kan eksponere forbruker for patogene bakterier som kan gi alvorlig sykdom, spesielt hos barn, eldre og personer med underliggende sykdommer. Resultatene underbygger viktigheten av Ă„ pasteurisere melk for Ă„ sikre mattryggheten, og at det er avgjĂžrende Ă„ lagre rĂ„ melk ved kontinuerlig lave temperaturer for Ă„ forebygge vekst av zoonotiske patogener

    Unresolved taxonomy confounds invasive species identification: the Lysmata vittata Stimpson, 1860 (Decapoda: Caridea: Lysmatidae) species complex and recent introduction of Lysmata vittata sensu stricto in the western Atlantic

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    Peppermint shrimp resembling Lysmata vittata Stimpson, 1860, a species native to the Indo- West Pacific, were found in the lower Chesapeake Bay and adjacent coastal embayments in 2013, representing the first recorded introduction of this species in the northwestern Atlantic. Conflicting morphological descriptions, inconsistent morphological terminology, and limited molecular data (i.e., unresolved taxonomy), as well as the destruction of the type material of L. vittata, created uncertainty regarding proper identification. We provide the first phylogeny incorporating individuals from across the presumed native and introduced range of L. vittata. Morphological and phylogenetic analyses clearly indicate L. vittata represents a species complex of two widely divergent groups: 1) “Bruce Type” with a uniramous dorsal antennule that agrees with A.J. Bruce’s 1990 redescription of L. vittata, and 2) “Rauli Type” with a one-article accessory branch on the dorsal antennule that agrees most closely with the junior synonym L. rauli Laubenheimer & Rhyne, 2010. Given the taxonomic ambiguity surrounding L. vittata, we designate the individual used by A.J. Bruce to redescribe L. vittata and incorporated in our analyses as a neotype to fix the identity of this species. We therefore identify introduced North American and New Zealand populations as L. vittata sensu stricto and postulate that the native range spans temperate/subtropical East Asia. These data suggest that L. rauli is a valid species, which includes a possible undescribed sister species. We confirm the presence of L. californica Stimpson, 1866 in New Zealand, the first non-native record for this species. We also provide data suggesting L. dispar Hayashi, 2007 may be more widespread in the Indo-West Pacific than currently known and consider L. lipkei Okuno & Fiedler, 2010 to be a likely junior synonym

    Post-Millennial Queer Sensibility: Collaborative Authorship as Disidentification in Queer Intertextual Commodities

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    This dissertation is examining LGBTQ+ audiences and creatives collaborating in the creation of new media texts like web shows, podcasts, and video games. The study focuses on three main objects or media texts: Carmilla (web series), Welcome to Night Vale (podcast), and Undertale (video game). These texts are transmedia objects or intertextual commodities. I argue that by using queer gestures of collaborative authorship that reaches out to the audience for canonical contribution create an emerging queer production culture that disidentifies with capitalism even as it negotiates capitalistic structures. The post-millennial queer sensibility is a constellation of aesthetics, self-representation, alternative financing, and interactivity that prioritizes community, trust, and authenticity using new technologies for co-creation. Within my study, there are four key tactics or queer gestures being explored: remediation, radical ambiguity and multi-forms as queer aesthetics, audience self-representation, alternative financing like micropatronage & licensed fan-made merchandise, and interactivity as performance. The goal of this project is to better understand the changing conceptions of authorship/ownership, canon/fanon (official text/fan created extensions), and community/capitalism in queer subcultures as an indicator of the potential change in more mainstream cultural attitudes. The project takes into consideration a variety of intersecting identities including gender, race, class, and of course sexual orientation in its analysis. By examining the legal discourse around collaborative authorship, the real-life production practices, and audience-creator interactions and attitudes, this study provides insight into how media creatives work with audiences to co-create self-representative media, the motivations, and rewards for creative, audiences, and owners. This study aims to contribute towards a fuller understanding of queer production cultures and audience reception of these media texts, of which there is relatively little academic information. Specifically, the study mines for insights into the changing attitudes towards authorship, ownership, and collaboration within queer indie media projects, especially as these objects are relying on the self-representation of both audiences and creatives in the formation of the text

    Cost-effective non-destructive testing of biomedical components fabricated using additive manufacturing

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    Biocompatible titanium-alloys can be used to fabricate patient-specific medical components using additive manufacturing (AM). These novel components have the potential to improve clinical outcomes in various medical scenarios. However, AM introduces stability and repeatability concerns, which are potential roadblocks for its widespread use in the medical sector. Micro-CT imaging for non-destructive testing (NDT) is an effective solution for post-manufacturing quality control of these components. Unfortunately, current micro-CT NDT scanners require expensive infrastructure and hardware, which translates into prohibitively expensive routine NDT. Furthermore, the limited dynamic-range of these scanners can cause severe image artifacts that may compromise the diagnostic value of the non-destructive test. Finally, the cone-beam geometry of these scanners makes them susceptible to the adverse effects of scattered radiation, which is another source of artifacts in micro-CT imaging. In this work, we describe the design, fabrication, and implementation of a dedicated, cost-effective micro-CT scanner for NDT of AM-fabricated biomedical components. Our scanner reduces the limitations of costly image-based NDT by optimizing the scanner\u27s geometry and the image acquisition hardware (i.e., X-ray source and detector). Additionally, we describe two novel techniques to reduce image artifacts caused by photon-starvation and scatter radiation in cone-beam micro-CT imaging. Our cost-effective scanner was designed to match the image requirements of medium-size titanium-alloy medical components. We optimized the image acquisition hardware by using an 80 kVp low-cost portable X-ray unit and developing a low-cost lens-coupled X-ray detector. Image artifacts caused by photon-starvation were reduced by implementing dual-exposure high-dynamic-range radiography. For scatter mitigation, we describe the design, manufacturing, and testing of a large-area, highly-focused, two-dimensional, anti-scatter grid. Our results demonstrate that cost-effective NDT using low-cost equipment is feasible for medium-sized, titanium-alloy, AM-fabricated medical components. Our proposed high-dynamic-range strategy improved by 37% the penetration capabilities of an 80 kVp micro-CT imaging system for a total x-ray path length of 19.8 mm. Finally, our novel anti-scatter grid provided a 65% improvement in CT number accuracy and a 48% improvement in low-contrast visualization. Our proposed cost-effective scanner and artifact reduction strategies have the potential to improve patient care by accelerating the widespread use of patient-specific, bio-compatible, AM-manufactured, medical components

    The Angel of Art Sees the Future Even as She Flies Backwards: Enabling Deep Relational Encounter Through Participatory Practice-Based Research.

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    This research addresses the current lack of opportunity within interdisciplinary arts practices for deep one-to-one relational encounters between creative practitioners operating in applied arts, performance, and workshop contexts with participant-subjects. This artistic problem is situated within the wider culture of pervasive social media, which continues to shape our interactions into forms that are characteristically faster, shorter, and more fragmented than ever before. Such dispersal of our attention is also accelerating our inability to deeply focus or relate for any real length of time. These modes of engaging within our technologically permeated, cosmopolitan and global society is escalating relational problems. Coupled with a constant bombardment of unrealistic visual images, mental health difficulties are also consequently rising, cultivating further issues such as identity ‘splitting’, (Lopez-Fernandez, 2019). In the context of the arts, this thesis proposes that such relational lack cannot be solved by one singular art form, one media modality, one existing engagement approach, or within a short participatory timeframe. Key to the originality of my thesis is the deliberate embodiment of a maternal experience. Feminist Lise Haller-Ross’ proposes that there is a ‘mother shaped hole in the art world’ and that, ‘as with the essence of the doughnut – we don’t need another hole for the doughnut, we need a whole new recipe’ (conference address, 2015). Indeed, her assertion encapsulates a need for different types of artistic and relational ingredients to be found. I propose these can be discovered within particular forms of maternal love; nurture; caring, and through conceptual relational states of courtship; intercourse; gestation, and birth. Furthermore, my maternal emphasis builds on: feminist, artist, and psychotherapist Bracha Ettinger’s (2006; 2015) notions of maternal, cohabitation and carrying; architect and phenomenologist Juhani Pallasmaa’s (2012) views on sensing and feeling; child psychoanalyst Donald Winnicott’s (1971) thoughts on transitional phenomena and perceptions of holding. Such psychotherapeutic and phenomenological theories are imbricated in-action within my multimodal arts processes. Additionally, by deliberately not privileging the ocular, I engage all my project participants senses and distil their multimodal data through an extended form of somatic and artistic Interpretive Phenomenological Analysis (IPA), (Smith, Flowers, and Larkin, 2009). IPA usefully focuses on the importance of the thematic and idiographic in terms of new knowledge generation, with an analytical focus on lived experience. Indeed, whilst the specifics of the participants in my minor and major projects are unique, my research activates and makes valid, findings that are collectively beneficial to the disciplines of applied and interdisciplinary arts; the field of practice-based research, and beyond. My original contribution to new knowledge as argued by this thesis, comprises both this text exposition and my practice. This sees the final generation of a new multimodal arts Participatory Practice-Based Framework (PartPb). Through this framework, the researcher-practitioner is seen to adopt a maternal role to gently guide project participants through four phases of co-created multimodal artwork generation. The four participatory ‘Phases’ are: Phase 1: Courtship – Digital Dialogues; Phase 2: Intercourse – Performative Encounters; Phase 3: Gestation – Screen Narratives; Phase 4: Birth – Relational Artworks. The framework also contains six researcher-only ‘Stages’: Stage 1: Participant Selection; Stage 2: Checking Distilled Themes; Stage 3: Location and Object Planning; Stage 4: Noticing, Logging, Sourcing; Stage 5: Collaboration and Construction; Stage 6: Releasing, Gifting, Recruiting. This new PartPb framework, is realised within a series of five practice-based (Pb) artworks called, ‘Minor Projects 1-5’, (2015-16) and Final Major Project, ‘Transformational Encounters: Touch, Traction, Transform’ (TETTT), (2018). These projects are likewise shaped through action-research processes of iterative testing, as developed from Candy and Edmonds (2010) Practice-based Research (PbR) trajectory. In my new PartPb framework, Candy, and Edmonds’ PbR processes are originally combined with a form of Fritz and Laura Perl’s Gestalt Experience Cycle (1947). This innovative fusion I come to term as a form of ‘Feeling Architecture,’ which is procedurally proven to hold and carry both researcher and participants alike, safely, ethically, and creatively through all Phases and Stages of artefact generation. Specifically, my new multimodal PartPb framework offers new knowledge to the field of Practice-Based Research (PbR) and practitioners working in multimodal arts and applied performance contexts. Due to its participatory focus, I develop on the term Practice-Based Research, (Candy and Edmonds, 2010) to coin the term Participatory Practice-Based Research, (PartPbR). The unique combination of multimodal arts and social-psychological methodologies underpinning my framework also has the potential to contribute to broader Arts, Well-Being, and Creative Health agendas, such as the UK government’s Social Prescribing and Arts and Health initiatives. My original framework offers future researchers’ opportunities to further develop, enhance and enrich individual and community well-being through its application to their own projects, and, in doing so, also starts to challenge unhelpful art binaries that still position community arts practices as somehow lesser to higher art disciplines

    Mixed Criticality Systems - A Review : (13th Edition, February 2022)

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    This review covers research on the topic of mixed criticality systems that has been published since Vestal’s 2007 paper. It covers the period up to end of 2021. The review is organised into the following topics: introduction and motivation, models, single processor analysis (including job-based, hard and soft tasks, fixed priority and EDF scheduling, shared resources and static and synchronous scheduling), multiprocessor analysis, related topics, realistic models, formal treatments, systems issues, industrial practice and research beyond mixed-criticality. A list of PhDs awarded for research relating to mixed-criticality systems is also included

    The relative effects of pace of life-history and habitat characteristics on the evolution of sexual ornaments: A comparative assessment

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    Selection may favor greater investment into sexual ornaments when opportunities for future reproduction are limited, for example, under high adult mortality. However, predation, a key driver of mortality, typically selects against elaborate sexual ornaments. Here, we examine the evolution of sexual ornaments in killifishes, which have marked contrasts in life-history strategy among species and inhabit environments that differ in accessibility to aquatic predators. We first assessed if the size of sexual ornaments (unpaired fins) influenced swimming performance. Second, we investigated whether the evolution of larger ornamental fins is driven primarily by the pace of life-history (investment into current vs. future reproduction) or habitat type (a proxy for predation risk). We found that larger fins negatively affected swimming performance. Further, males from species inhabiting ephemeral habitats, with lower predation risk, had larger fins and greater sexual dimorphism in fin size, compared to males from more accessible permanent habitats. We show that enlarged ornamental fins, which impair locomotion, evolve more frequently in environments that are less accessible to predators, without clear associations to life-history strategy. Our results provide a rare link between the evolution of sexual ornaments, effects on locomotion performance, and natural selection on ornament size potentially through habitat differences in predation risk

    Fungos marinhos: diversidade e potencial biotecnolĂłgico

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    Marine fungi are a prolific group of organisms that have been largely neglected for a long time. Over the last years, attention turned to the marine environment, with the recognition that marine organisms represent a rich source of natural products. The marine mycobiome has many species still to be identified and the ones known still underutilized for biotechnological applications. In Portugal, despite its very large coastline and privileged relationship with the sea, there are only few studies on marine fungi. Thus, the main goal of this thesis was to contribute to disclose the untapped diversity and the biotechnological potential of the marine mycobiome from the Portuguese coastline and in the estuary of Ria de Aveiro. To achieve this, three different approaches were used. First, fungi were isolated from algae, drift- and submerged wood, saline water, and sponges. The 1312 isolates obtained were initially subjected to microsatellite-primed PCR to analyze the genetic fingerprinting patterns to separate and discriminate different groups in the collection. From this collection, 243 different fungal species were identified based on DNA sequence data. Eighteen fungal species and one new genus were identified, which were circumscribed based on morphological and phylogenetic analysis. Furthermore, some taxonomic ambiguities have been resolved. Secondly, eight fungal strains were selected for biological activities characterization based on their enzymatic profile and antibacterial activity. Mycelia aqueous extracts and culture media methanolic extracts, obtained from liquid fermentation, were characterized regarding their antibacterial, antifungal, antioxidant, and cytotoxic activities. In addition, the effect of sea salt on fungal bioactivities was evaluated. In general, the extracts of Aspergillus affinis, Penicillium lusitanum, Emericellopsis cladophorae and Trichoderma aestuarinum were able to inhibit the growth of pathogenic bacteria and fungi. Our results also demonstrated that the activity profiles from the extracts of the marine fungi studied were different in response to the presence of sea salt. Finally, A. affinis and E. cladophorae were characterized in more detail with their metabolomes and genomes sequenced. Both species contain many unknown biosynthetic gene clusters, genes encoding for osmolytes’ biosynthetic processes, ion transport systems, and are rich in carbohydrate active enzymes, which can contribute to understand their adaptation to the marine environment. Furthermore, the compound library built from the crude extracts for both species confirmed the presence of antifungal, antibacterial, antitumor, antiviral, and anti-inflammatory metabolites. The outcome of this work confirmed that the marine mycobiome is highly diverse and can yield novel marine fungal taxa which must continue to be explored contributing to unveil their biodiversity, ecological importance, and natural products research.Os fungos marinhos sĂŁo um grupo prolĂ­fico de organismos que tem sido amplamente negligenciado. Ao longo dos Ășltimos anos, as atençÔes voltaramse para o meio marinho, com o reconhecimento de que os organismos marinhos constituem uma rica fonte de produtos naturais. O micobioma marinho tem muitas espĂ©cies ainda por desvendar e subutilizadas para aplicação biotecnolĂłgica. Em Portugal, apesar da extensa linha costeira e da relação privilegiada com o mar, sĂŁo poucos os estudos sobre fungos marinhos. Assim, o objetivo desta tese foi contribuir para a divulgação da diversidade e do potencial biotecnolĂłgico contido no micobioma marinho da costa portuguesa e no estuĂĄrio da Ria de Aveiro. Para isso, trĂȘs abordagens foram utilizadas. Primeiro, os fungos foram isolados de algas, madeira Ă  deriva e submersa, ĂĄgua salgada e esponjas. Obtiveram-se 1312 isolados que foram inicialmente submetidos a MSP-PCR para analisar os padrĂ”es de impressĂŁo digital genĂ©tica para discriminar diferentes grupos na coleção. Desta coleção, foram identificas 243 espĂ©cies diferentes de fungos com base em dados de sequĂȘncia de DNA. Foram identificadas dezoito novas espĂ©cies e um novo gĂ©nero, que foram descritos com base em anĂĄlises morfolĂłgicas e filogenĂ©ticas. AlĂ©m disso, algumas ambiguidades taxonĂłmicas foram resolvidas. Em segundo lugar, oito estirpes de fungos foram selecionadas para a caracterização de bioatividades com base nos seus perfis enzimĂĄticos e atividades antimicrobianass. Os extratos aquosos dos micĂ©lios e os extratos metanĂłlicos dos meios de cultura obtidos por fermentação lĂ­quida foram caracterizados quanto Ă s atividades antibacteriana, antifĂșngica, antioxidante e citotĂłxica. De um modo geral, os extratos de Aspergillus affinis, Penicillium lusitanum, Emericellopsis cladophorae e Trichoderma aestuarinum apresentaram atividade contra bactĂ©rias e fungos patogĂ©nicos. Os resultados demonstraram tambĂ©m que os perfis de atividade dos extratos destes fungos marinhos sĂŁo diferentes em resposta Ă  presença de sal marinho. Por fim, A. affinis e E. cladophorae foram estudados mais detalhadamente, caracterizando-se os seus metabolomas e genomas. Ambas as espĂ©cies contĂȘm grupos de genes biossintĂ©ticos desconhecidos, genes que codificam processos biossintĂ©ticos de osmĂłlitos e sistemas de transporte de iĂ”es, e sĂŁo ricas em enzimas com atividade sobre hidratos de carbono, o que pode contribuir para entender a sua adaptação ao ambiente marinho. AlĂ©m disso, a biblioteca de compostos construĂ­da a partir dos extratos brutos para ambas as espĂ©cies confirmou a presença de metabolitos antifĂșngicos, antibacterianos, antitumorais, antivirais e anti-inflamatĂłrios. O resultado deste trabalho confirmou que o micobioma marinho Ă© altamente diversificado e pode ter novos taxa de fungos marinhos que devem continuar a ser explorados contribuindo para desvendar a sua biodiversidade, importĂąncia ecolĂłgica e pesquisa de produtos naturais.Programa Doutoral em Biologi
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