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Advancing glioblastoma research with innovative brain organoid-based models
No full textGlioblastoma (GBM) is a relatively rare but highly aggressive form of brain cancer characterized by rapid growth, invasiveness, and resistance to standard therapies. Despite significant progress in understanding its molecular and cellular mechanisms, GBM remains one of the most challenging cancers to treat due to its high heterogeneity and complex tumor microenvironment. To address these obstacles, researchers have employed a range of models, including in vitro cell cultures and in vivo animal models, but these often fail to replicate the complexity of GBM. As a result, there has been a growing focus on refining these models by incorporating human-origin cells, along with advanced genetic techniques and stem cell-based bioengineering approaches. In this context, a variety of GBM models based on brain organoids were developed and confirmed to be clinically relevant and are contributing to the advancement of GBM research at the preclinical level. This review explores the preparation and use of brain organoid-based models to deepen our understanding of GBM biology and to explore novel therapeutic approaches. These innovative models hold significant promise for improving our ability to study this deadly cancer and for advancing the development of more effective treatments.2024.01695.B
A first look at the gravettian open-air site ollersdorf-heidenberg (Austria): recent fieldwork and first results on stratigraphy, chronology, organic preservation and combustion activity
No full textThe Middle Danube region is a key area for understanding Upper Palaeolithic hunter-gatherer behaviours in a climatic context due to its long loess-palaeosol sequences and rich archaeological record spanning from the onset of the Upper Palaeolithic to the Last Glacial Maximum and beyond. Recently, new approaches focusing on high-resolution studies of the stratigraphy, geoarchaeological studies at microscopic scale and investigations of organic matter at molecular scale (biomarker analyses) have shown great new insights in human behaviour. Many sites in the Middle Danube region have been excavated a long time ago without opportunity to apply such approaches. The aim of this paper is to introduce Ollersdorf-Heidenberg, a loess open-air site. The site is located similar to 26 km northeast of Vienna close to the Morava River valley and preserves several Upper Palaeolithic archaeological horizons. The site has been known since a pipeline construction in 1998. Here, we report the first results of new research at the site including new excavations in two trenches. We describe and analyse the stratigraphy, present a first radiocarbon date, describe and analyse lithic and faunal collections, and assess potential in situ combustion activity and the preservation of organic matter. Research at the site is ongoing, but our preliminary results let us suggest good preservation of organic matter and, hence, Ollersdorf-Heidenberg has a remarkable potential for providing valuable insights in past hunter-gatherer behaviours at the climatic downturn towards the Last Glacial Maximum.06104.17.01; 06104.17.02; 06104.18.0
Building company resilience: Determinants in the tourism industry
No full textWhat characteristics enable a company in the tourism industry to withstand and recover from disruptive events such as a global pandemic or a war? How can these firms enhance their resilience? This paper presents a systematic literature review of peer-reviewed publications on company resilience within the tourism industry to address these critical questions. Despite the current significance of these topics, existing research is fragmented and unconsolidated. Our findings reveal a range of perspectives and factors that influence company resilience, with clear evidence that human capital plays a pivotal role in the tourism industry’s ability to remain resilient. We also identify theoretical and practical implications, along with directions for future research.UIBD/152309/2021N/
Puzzling out the ecological niche construction for nitrogen fixers in a coastal upwelling system
No full textDiazotrophs are a diverse group of microorganisms that can fertilize the ocean through biological nitrogen fixation (BNF). Due to the high energetic cost of this process, diazotrophy in nitrogen-replete regions remains enigmatic. We use multidisciplinary observations to propose a novel framework for the ecological niche construction of nitrogen fixers in the upwelling region off NW Iberia-one of the most productive coastal regions in Europe-characterized by weak and intermittent wind-driven upwelling and the presence of bays. The main diazotroph detected (UCYN-A2) was more abundant and active during summer and early autumn, coinciding with relatively high temperatures (>16 degrees C), low nitrogen:phosphorus ratios (N:P 75%) to the total dissolved inorganic nitrogen available. Furthermore, nutrient amendment experiments showed that BNF is detectable when phytoplankton biomass and productivity are nitrogen limited. Seasonally recurrent biogeochemical processes driven by hydrography create an ecological niche for nitrogen fixers in this system. During the spring-summer upwelling, nondiazotroph autotrophs consume nitrate and produce organic matter inside the bays. Thereafter, the combined effect of intense remineralization on the shelf and sustained positive circulation within the bays in late summer-early autumn, conveys enhanced ammonium content and excess phosphate into the warm surface layer. The low N:P ratio confers a competitive advantage to diazotrophs since they are not restricted by nitrogen supply. The new nitrogen supply mediated by BNF could extend the productivity period, and may be a key reason why upwelling bays are more productive than upwelled offshore waters.FJC2019-038970-I; IN607A2018/2; CTM2016-75451-C2-1-
Spatial and temporal size distribution of swordfish in the Atlantic Ocean: implications for conservation and management
No full textSwordfish (Xiphias gladius) is a common target species of surface pelagic longline fisheries. In the Atlantic Ocean and Mediterranean Sea, swordfish is managed as three separate stocks, all having management measures in place to rebuild or conserve the stocks, including minimum landing sizes. The objective of this study was to review size data for swordfish in the Atlantic Ocean, model the sex-specific size distribution and determine areas where there is higher likelihood of capturing undersized fish. The size distribution differed between males and females and varied by quarter, indicating movements of large fish between temperate and tropical waters. Undersized fish seems to occur in association with coastal waters, with higher proportions in the Northwest Atlantic and tropical areas. This study provides a better understanding of the temporal and spatial size and sex distribution of swordfish and presents insights into the distribution of undersized swordfish that is subject to management measures
An efficient procedure to extract RNA from a single Aphis gossypii and Aphis spiraecola for detecting Citrus tristeza virus by nested RT-PCR
No full textA simple protocol to extract RNA from a single wingless aphid, Aphis gossypii and Aphis spiraecola, using liquid nitrogen and Tri-Reagent is described. A nested reverse-transcription polymerase chain reaction with degenerate primers enabled Citrus tristeza virus (CTV) detection in these aphid species collected from an infected tangor ‘Ortanique’ (Citrus × sinensis (L.) Osbeck × Citrus reticulata Blanco) in the field. The procedure enabled a CTV detection rate of 75% in the A. gossypii and A. spiraecola evaluated.PTDC/BAA-AGR/30957/2027info:eu-repo/semantics/publishedVersio
User-generated content and its impact on purchase intent for tourism products: a comparative analysis of millennials and centennials on tiktok
No full textIn an increasingly technological society, online social networks are essential to support consumer purchasing decisions, primarily through User Generated Content (UGC). In this research, we look at the influence of UGC on purchase intent applied to the tourism product on the TikTok social network. In this sense, a survey was applied to TikTok users aged between 18 and 42 to compare their behaviour with that of the two generations: Millennials and Centennials. The results indicate a relationship of influence between credibility and the usefulness of information and between usefulness and social influence on the intention to buy tourism products and services. In addition, a comparison was made between the results of the sample of individuals belonging to the Millennial Generation and the sample of individuals belonging to the Centennial Generation, with the main discrepancy in the results being the relationship between the need for information and the usefulness of information. These insights pave the way for further research aimed at establishing more robust conclusions in this area
Daniel H. Burckhardt at 70—an appreciation
No full textPD Dr Daniel H. Burckhardt (Figs 1–4) turned 70 on 26 July 2023.His extensive body of work on the taxonomy of insects, initiated even before his doctoral thesis on Western Palaearctic Aphalaridae in 1983, has since expanded to encompass all major psyllid groups (Hemiptera: Sternorrhyncha: Psylloidea), both extant and extinct, but also moss bugs (Hemiptera: Coleorrhyncha) and several families of beetles (Coleoptera, mainly Passandridae, but also Jacobsoniidae, Pterogeniidae and Staphylinidae). These contributions have had a profound and lasting impact on our global understanding of these relatively small and often overlooked groups of insects. The biographical details of Daniel Burckhardt’s career and life will not be revisited here, as they have already been thoroughly documented elsewhere. In terms of his tireless dedication and remarkable productivity, the comprehensive list of his publications at the end of this article speaks for itself.Another telling measure of his influence within entomology is the number of PhD students he has mentored, formally or informally, many of whom have gone on to establish successful careers in leading research institutions and natural history museums across Europe and beyond. At a time when taxonomic expertise is rapidly declining, with serious implications for biodiversity research, agriculture and conservation, his intellectual legacy, marked by rigour, precision, and clarity, has been effectively passed on to the next generation. This tribute aims above all to highlight the personal and professional impact Daniel Burckhardt has had on so many colleagues and collaborators. Rather than a conventional biography, it offers a space for those who have worked with him to share their experiences and anecdotes, and to reflect on the influence he has had on their scientific journeys
Actividades do Centro de Estudos Arqueológicos do concelho de Oeiras (CEACO) desenvolvidas em 2024
No full textOs factos elencados neste Relatório confirmam o reconhecimento público ao nível do interesse e importância conferidos ao trabalho desenvolvido no CEACO, decisivos para a consolidação e afirmação das suas competências e atribuições no quadro da investigação, salvaguarda e divulgação do Património arqueológico oeirense.
1. Trabalhos laboratoriais e de gabinete
2. Revista Estudos Arqueológicos de Oeiras
3. Terceiro Colóquio Internacional História das Ideias e dos Conceitos em Arqueologia
4. Ciclo de conferências Pré-História do concelho de Oeiras
5. Visitas guiadas
6. Palestras e conferências
7. Colaborações
8. Quarta Edição do Prémio de Arqueologia Professor Doutor Octávio da Veiga Ferreira
9. Considerações finai
An evo-devo approach to vertebral body development: going back to progenitors
No full textThe segmented signal for vertebral body development is conveyed, in zebrafish, through mineralization of the notochordal sheath and, in chicken, through resegmentation of the most medially located ventral sclerotome cells, with the contribution of the notochord still unclear. Along with the different size of the notochord in these two embryos, this leads to the hypothesis that evolutionary changes in the expression territories of transcription factors could underlie these differences. In the zebrafish axial(notochord)/paraxial(PSM/somite/sclerotome) mesoderm progenitor region, flh normally represses spt that normally defines paraxial mesoderm fate, leading to an axial mesoderm one instead.
The aims of this thesis were to clarify the role of the notochord in chicken segmented vertebral body formation and investigate the role of transcription factor evolutionary changes in this process’s differences between zebrafish and chicken. In chapter II we thoroughly describe the first morphological landmark of segmented vertebrae, Von Ebner’s fissure, using it as a proxy to observe that the notochord and dermomyotome are not responsible for vertebral body segmented signal initiation. In chapter III, through CNOT2 electroporation experiments, we observe an increase in the axial mesoderm size (notochord and floor plate), accompanied by a shortening of axial length and downregulation of TBX6L. We conclude that CNOT2 represses TBX6L, leading axial/paraxial progenitor cells to assume an axial mesoderm cell fate. In chapter IV, we fill in a lingering chicken embryo knowledge gap, by producing a detailed quantification of early axis elongation. At the same time, we provide a reproducible and precise staging system and a morphometric tool to analyze experimental data.
This thesis demonstrates the evolutionary shift in preponderance from the notochord to the PSM/somites/sclerotome in the role on segmented signal location and axial elongation. It also proposes that changes in the flh/CNOT2 and spt/TBX6L expression territories in the axial/paraxial mesoderm region are underlying these shifts.A segmentação é uma característica comum a uma grande percentagem de animais que permite uma organização funcional e estrutural do corpo. Esta característica é particularmente evidente nos animais vertebrados que possuem um esqueleto axial formado por estruturas ósseas repetidas ao longo do eixo antero-posterior do corpo, as vértebras. Estas são compostas por um núcleo ósseo central denominado “corpo vertebral” e por arcos localizados dorsalmente e/ou ventralmente ao corpo vertebral, denominados “arcos vertebrais”.
A formação do corpo vertebral é um processo muito interessante do ponto de vista da Biologia Evolutiva e do Desenvolvimento, já que ocorre de diferentes maneiras em diferentes grupos de animais. Geralmente, o corpo vertebral forma-se graças à contribuição de duas estruturas embrionárias, a notocorda e o sómito. A notochorda é uma estrutura embrionária axial alongada composta por células vacuolizadas no lúmen e coberta por uma bainha envolvente com células denominadas cordoblastos. Esta estrutura representa o primeiro esqueleto embrinário, tendo várias funções, estruturais e de sinalização genética. Os sómitos são esferas de células mesenquimatosas localizadas em pares, flanqueando a notocorda. Estes formam-se sequencialmente a partir da mesoderme pré-somitica, através de transições epitélio-mesênquima num processo é altamente regulado por um conjunto de genes expressos ciclicamente denominado “relógio embrionário”. Cada sómito dá origem a vários compartimentos (dependendo das espécies) que irão dar origem a diferentes tecidos: o esclerótomo que dá origem a tecidos ósseos e o miótomo que origina tecidos musculares e o dermamiótomo que origina vários tecidos como derme e músculo, entre outros. Apesar do corpo da vértebra ter uma contribuição destas duas estruturas, a importância de cada para o processo é diferente entre vários grupos de animais, sobretudo na estrutura que confere o sinal necessário para a formação de corpos vertebrais segmentados. Em peixes como o peixe-zebra, este sinal provém da mineralização da baínha da notocorda pelos cordoblastos. Em amniotas, como a galinha, este sinal começa por aparecer sob a forma de uma divisão rostro-caudal do esclerótomo em dois compartimentos. Esta padronização é mantida na formação do corpo vertebral através do processo de resegmentação. Neste, cada vértebra é formada pela junção da metade caudal de um esclerótomo com a metade rostral do esclerótomo seguinte. A fissura que separa as duas metades do esclerótomo, denominada “fissura de Von Ebner”, é então o primeiro sinal morfológico da segmentação das vértebras. Nestes animais o papel da notocorda é ainda uma incógnita, já que experiências de remoção desta estrutura resultam na formação de corpos de vértebra fundidos.
Por outro lado, o tamanho da notocorda relativamente ao embrião é consideravelmente maior no embrião de peixe-zebra do que no de galinha. O contrário acontece com o esclerótomo, em que este corresponde à maior percentagem de tamanho do sómito maduro no embrião de galinha, sendo apenas uma fina linha de células no embrião de peixe-zebra. Isto leva-nos questionar que transformações poderão ter ocorrido que explicariam estas diferenças. A chave para a resposta a esta pergunta está no processo de desenvolvimento, já que, muitas vezes, as diferenças neste processo são a razão para as diferenças morfológicas observadas entre espécies.
Tanto a notocorda como os sómitos provém de células da mesoderme, mais especificamente da mesoderme axial e paraxial, respectivamente. Durante o processo de desenvolvimento, existem zonas progenitoras que contém factores de transcrição, cuja expressão controla o seu destino. Mutações nestes genes podem causar transformações homeóticas, isto é, conversão das células de uma estrutura noutra diferente. Dois genes descobertos em peixe-zebra, quando mutados, causam alterações deste género: O gene flating head (flh), quando mutado, leva à transformação total da notocorda em sómito, enquanto o gene spadetail (spt) leva a uma conversão parcial de células dos sómitos em notocorda. Foi então descoberto que o flh reprime o spt em células progenitoras de notocorda, levando-as a assumir um destino de notocorda em vez de sómito.
Assim sendo, os objectivos desta tese foram 1) clarificar o papel da notocorda na formação do corpo da vértebra; 2) investigar se a razão das diferenças observadas no papel da notocorda neste processo se deve à alteração nos territórios de expressão de genes como o flh ou o spt.
No capítulo II procedemos ao estudo do efeito da notocorda e do dermamiótomo na segmentação do corpo da vértebra, usando para tal a fissura de Von Ebner como indicador desta segmentação. Para o fazer, começamos por descrever este marco morfológico, tendo descoberto que ele aparece em embriões a partir do sómito IX, Com este conhecimento adquirido, procedemos a experiências de remoção da notocorda e do dermomiótomo e avaliação da presença da fissura de Von Ebner. Em ambas as experiências, a fissura manteve-se inalterada, sugerindo que as duas estruturas não possuem um papel na segmentação do corpo da vértebra.(…)This work was supported by National Portuguese funding through FCT – Fundação para a Ciência e Tecnologia, scholarship SFRH/BD/84825 /201