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Ensuring Access to Safe and Nutritious Food for All Through the Transformation of Food Systems
ENABLING EFFICIENT FLEET COMPOSITION SELECTION THROUGH THE DEVELOPMENT OF A RANK HEURISTIC FOR A BRANCH AND BOUND METHOD
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?
The worldwide emerging trend of eating ânaturalâ 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 cowâs 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
cowâs 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.Ă
spise mat som er mindre prosessert og mer «naturlig» er en pÄgÄende
trend i Norge og i andre deler av verden. Interessen for Ă„ drikke melk som
ikke er varmebehandlet, sÄkalt rÄ melk, er ogsÄ Þkende. I Norge er det pÄbudt
Ă„ pasteurisere melk fĂžr kommersielt salg for Ă„ beskytte forbrukeren mot
sykdomsfremkallende mikroorganismer. Fagfolk advarer mot Ä drikke rÄ
melk, og pÄpeker risikoen for Ä 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
speneprÞver fra melkegÄrder i sÞrÞst Norge, samlet vi ogsÄ miljÞprÞver fra
de samme gÄrdene for Ä kartlegge forekomst og for Ä 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 pÄ gÄrdene. Bakteriene kan overfÞres fra gÄrdsmiljÞet
til melkekjeden og dermed utfordre mattryggheten. Disse bakteriene har
forÄrsaket melkebÄrne sykdomsutbrudd over hele verden, ogsÄ 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 matbÄrne zoonotiske
sykdommene vi har i den vestlige verden.
Resultater fra denne oppgaven viser en hĂžy forekomst av de tre patogenene i
gÄrdsmiljÞet. 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 rÄ melk kan
inneholde patogene STEC. For Ă„ videre vurdere risikoen for Ă„ bli syk av STEC
fra rÄ melk undersÞkte vi hvordan de fire eae-positive isolatene vokste i rÄ
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 fÞrste 24 timene, deretter
stoppet reduksjonen i antall bakterier. Disse resultatene viser hvor viktig det
er Ä ha stabil lav lagringstemperatur for rÄ melk, helst < 4°C.
L. monocytogenes isolatene som ble samlet inn fra melkegÄrdene 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
sÄ man at en klone kan persistere pÄ en gÄrd over tid og at melk kan
kontamineres av L. monocytogenes kloner som er til stede i gÄrdsmiljÞet.
Til tross for smÄ testvolum av tankmelken (25 mL) fant vi bÄde 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 pÄ bÄs byttes ut med lÞsdriftssystemer og melkeroboter.
Forekomsten av de tre patogenene funnet i denne studien var hĂžyere i
besetningene med lĂžsdrift sammenliknet med besetningene som hadde
melkekyrne oppstallet pÄ bÄs.
Pasteurisering er et viktig forebyggende tiltak for Ă„ beskytte konsumenter fra
mikrobielle patogener, og i de fleste EU-land er kommersielt salg av rÄ melk
juridisk begrenset. Denne studien viser at oppstallingstype kan pÄvirke
nivÄene av patogene bakterier i gÄrdsmiljÞet og i rÄ melk. Inntak av rÄ 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 avgjÞrende Ä lagre rÄ 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
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) âBruce Typeâ with a uniramous dorsal antennule that agrees with A.J. Bruceâs 1990 redescription of L. vittata, and 2) âRauli Typeâ 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
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
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.
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 âsplittingâ, (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-Rossâ proposes that there is a âmother shaped hole in the art worldâ and that, âas with the essence of the doughnut â we donât need another hole for the doughnut, we need a whole new recipeâ (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 Ettingerâs (2006; 2015) notions of maternal, cohabitation and carrying; architect and phenomenologist Juhani Pallasmaaâs (2012) views on sensing and feeling; child psychoanalyst Donald Winnicottâs (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 âPhasesâ are: Phase 1: Courtship â Digital Dialogues; Phase 2: Intercourse â Performative Encounters; Phase 3: Gestation â Screen Narratives; Phase 4: Birth â Relational Artworks. The framework also contains six researcher-only âStagesâ: 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, âMinor Projects 1-5â, (2015-16) and Final Major Project, âTransformational Encounters: Touch, Traction, Transformâ (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 Edmondsâ PbR processes are originally combined with a form of Fritz and Laura Perlâs Gestalt Experience Cycle (1947). This innovative fusion I come to term as a form of âFeeling Architecture,â 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 governmentâs Social Prescribing and Arts and Health initiatives. My original framework offers future researchersâ 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)
This review covers research on the topic of mixed criticality systems that has been published since Vestalâs 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
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
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 osmolytesâ
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 espécies ainda por desvendar e subutilizadas para
aplicação biotecnológica. Em Portugal, apesar da extensa linha costeira e da
relação privilegiada com o mar, são 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 padrÔes de impressão digital
genética para discriminar diferentes grupos na coleção. Desta coleção, foram
identificas 243 espécies diferentes de fungos com base em dados de
sequĂȘncia de DNA. Foram identificadas dezoito novas espĂ©cies e um novo
género, que foram descritos com base em anålises morfológicas e
filogenéticas. Além disso, algumas ambiguidades taxonómicas foram
resolvidas.
Em segundo lugar, oito estirpes de fungos foram selecionadas para a
caracterização de bioatividades com base nos seus perfis enzimåticos e
atividades antimicrobianass. Os extratos aquosos dos micélios 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 bactérias e fungos patogénicos. Os resultados
demonstraram também que os perfis de atividade dos extratos destes fungos
marinhos são diferentes em resposta à presença de sal marinho.
Por fim, A. affinis e E. cladophorae foram estudados mais detalhadamente,
caracterizando-se os seus metabolomas e genomas. Ambas as espécies
contĂȘm grupos de genes biossintĂ©ticos desconhecidos, genes que codificam
processos biossintéticos de osmólitos e sistemas de transporte de iÔes, e são
ricas em enzimas com atividade sobre hidratos de carbono, o que pode
contribuir para entender a sua adaptação ao ambiente marinho. Além 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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