Cellular velocity, electrical persistence and sensing in developed and vegetative cells during electrotaxis

Cells have the ability to detect electric fields and respond to them with directed migratory movement. Investigations identified genes and proteins that play important roles in defining the migration efficiency. Nevertheless, the sensing and transduction mechanisms underlying directed cell migration are still under discussion. We use Dictyostelium discoideum cells as model system for studying eukaryotic cell migration in DC electric fields. We have defined the temporal electric persistence to characterize the memory that cells have in a varying electric field. In addition to imposing a directional bias, we observed that the electric field influences the cellular kinematics by accelerating the movement of cells along their paths. Moreover, the study of vegetative and briefly starved cells provided insight into the electrical sensing of cells. We found evidence that conditioned medium of starved cells was able to trigger the electrical sensing of vegetative cells that would otherwise not orient themselves in the electric field. This observation may be explained by the presence of the conditioned medium factor (CMF), a protein secreted by the cells, when they begin to starve. The results of this study give new insights into understanding the mechanism that triggers the electrical sensing and transduces the external stimulus into directed cell migration. Finally, the observed increased mobility of cells over time in an electric field could offer a novel perspective towards wound healing assays

Exploring intraspecific variability – biochemical and morphological traits of the sugar kelp Saccharina latissima along latitudinal and salinity gradients in Europe

Broadly distributed seaweeds, such as the boreal-temperate kelp species Saccharina latissima, contain a multitude of metabolites supporting acclimation to environmental changes, such as temperature and salinity. In Europe, S. latissima occurs along the coasts from Spitsbergen to Portugal, including the Baltic Sea, exhibiting great morphological plasticity. We investigated the morphological and biochemical traits of field-collected sporophytes from 16 different locations across the species entire distributional range in relation to local abiotic conditions (sea surface temperature, salinity). By statistically linking morphological and biochemical data to geographic information that also took into account the respective sampling depth, we aimed to obtain first insights into the site-specific adaptive features of this species. Frond length and width, mannitol and phlorotannin contents, and molar C:N ratio showed strong intraspecific variability among S. latissima sporophytes dependent on individual local abiotic drivers. Despite the conspicuous impact of local abiotic factors on specimens’ morphology, we could not determine habitat-specific signatures in the biochemical phenotypes. Even though our findings are based on a relative small sample size per site, they cover a broad biogeographical range and support a high plasticity of S. latissima sporophytes. The study provides a first base for studying separation processes of populations across latitudes and conservation ecology

Transgenerational temperature effects in the kelp Laminaria digitata

Transgenerational effects (effects of parental environment on offspring traits) have recently gained attention as a means of fast response to changing environmental conditions, e.g. under climate change. In temperate and polar rocky coastal ecosystems, kelps form the base of complexly structured and highly diverse species associations. This study investigates the potential for temperature-mediated transgenerational plasticity along the development from haploid parents (gametophytes) to their juvenile diploid offspring (sporophytes) in a geographically isolated population of the brown alga Laminaria digitata from the island of Helgoland (North Sea). We sampled spores from wild donor sporophytes, which we raised at 5 and 15 °C during gametogenesis, and reared the resulting young sporophytes for three months in a full-factorial split design while keeping genetic lineages separate. A concluding 12-day experiment on growth, biochemistry (carbon, mannitol content) and photosynthetic characteristics (maximum quantum yield Fv/Fm, maximum electron transport rate rETRmax) of five genetic lineages allowed for the separation of late temperature (12 day) responses, within-generation plasticity (early temperature) and transgenerational plasticity (gametogenesis temperature) in response to 5 and 15 °C. We observed significant two- and three-way interactions between gametogenesis temperature and early and late sporophyte temperatures for all parameters. While interactive effects between early and late experimental temperatures probably represent acclimation processes, interactions involving gametogenesis temperature indicate transgenerational effects. The direction of these effects differed between parameters. A main effect is that only with a history of 5 °C as gametogenesis and early temperature, sporophytes are growing faster at 5 than 15 °C over 12 days late temperature. According to our results, the temperature experienced by parents during gametogenesis influences temperature reaction norms in three- to four-month-old Laminaria digitata sporophytes. This, to our knowledge, is the first evidence for transgenerational plasticity in kelps

Thermal Plasticity of the Kelp Laminaria digitata (Phaeophyceae) Across Life Cycle Stages Reveals the Importance of Cold Seasons for Marine Forests

Phenotypic plasticity (genotype × environment interaction) is an especially important means for sessile organisms to cope with environmental variation. While kelps, the globally most productive group of seaweeds, generally possess a wide thermal performance range, kelp populations at their warm distribution limits are threatened by ocean warming. Here, we investigated effects of temperature during ontogeny of the kelp Laminaria digitata across haploid gametophyte and diploid sporophyte life cycle stages in five distinct genetic lines. We hypothesized that thermal plasticity increases trait performance of juvenile sporophytes in experimental temperatures that match the temperature experienced during gametogenesis and recruitment, and that plasticity differs among genetic lines (genetic variation for plasticity). We applied a full-factorial experimental design to generate different temperature histories by applying 5 and 15°C during meiospore germination, gametogenesis of parental gametophytes and recruitment of offspring sporophytes (19–26 days), and juvenile sporophyte rearing (91–122 days). We then tested for thermal plasticity among temperature history treatments at 5 and 15°C in a final 12-day experiment assessing growth, the storage compound mannitol, carbon and nitrogen contents, and fluorometric responses in 3–4 month old sporophytes for five genetic lines. Our study provides evidence for the importance of cold temperatures at early development on later sporophyte performance of L. digitata. Gametogenesis and recruitment at 5°C promoted higher growth of offspring sporophytes across experimental temperatures. While photosynthetic capacity was higher at 15°C, carbon and nitrogen storage were higher at 5°C, both showing fast acclimation responses. We identified an important role of genetic variation for plasticity in shaping L. digitata’s thermal plasticity. Trait performance at 5 or 15°C (reaction norm slopes) differed among genetic lines, even showing opposite response patterns. Interestingly, genetic variation for plasticity was only significant when sporophytes were reared at 5°C. Thus, we provide evidence that the cold-temperate to Arctic kelp species, L. digitata, which possesses a wide temperature tolerance between 0 and 23°C, is impaired by warm temperature during gametogenesis and recruitment, reducing growth of juvenile sporophytes and expression of variable thermal plasticity in the wild

The sugar kelp Saccharina latissima I: recent advances in a changing climate

• Background: The sugar kelp Saccharina latissima is a Laminariales species widely distributed in the Northern Hemisphere. Its physiology and ecology have been studied since the 1960s, given its ecological relevance on western temperate coasts. However, research interest has been rising recently, driven mainly by reports of negative impacts of anthropogenically induced environmental change and by the increased commercial interest in cultivating the species, with several industrial applications for the resulting biomass. • Scope: We used a variety of sources published between 2009 to May 2023 (but including some earlier literature where required), to provide a comprehensive review of the ecology, physiology, biochemical and molecular biology of S. latissima. In so doing we aimed to better understand the species’ response to stressors in natural communities, but also inform the sustainable cultivation of the species. • Conclusion: Due to its wide distribution, S. latissima has developed a variety of physiological and biochemical mechanisms to adjust to environmental changes, including adjustments in photosynthetic parameters, modulation of osmolytes and antioxidants, reprogramming of gene expression and epigenetic modifications, among others summarized in this review. This is particularly important because massive changes in the abundance and distribution of S. latissima have already been observed. Namely, presence and abundance of S. latissima has significantly decreased at the rear edges on both sides of the Atlantic, and increased in abundance at the polar regions. These changes were mainly caused by climate change and will therefore be increasingly evident in the future. Recent developments in genomics, transcriptomics and epigenomics have clarified the existence of genetic differentiation along its distributional range with implications in the fitness at some locations. The complex biotic and abiotic interactions unraveled here demonstrated the cascading effects the disappearance of a kelp forest can have in a marine ecosystem. We show how S. latissima is an excellent model to study acclimation and adaptation to environmental variability and how to predict future distribution and persistence under climate change.publishedVersio

Módulo para mensuração do desempenho competitivo de nanomateriais aplicados ao setor cosmético / Module for measuring competitive performance of nanomaterials applied to the cosmetic sector

 Busca-se proporcionar uma nova ferramenta que potencialize o entendimento de todos os fatores envolvidos os quais são fundamentais para a redução do tempo da consolidação do conhecimento, que por hora está latente na bancada dos pesquisadores que buscam na nanociência. O processo de decisão sobre o  potencial de desenvolvimento de novos processos associados a pesquisa em nanomateriais demanda o tratamento de dados inter-relacionados, os tomadores de decisões buscam em modelos uma forma de tratar todas as informações, sendo que este trabalho aborda o potencial do uso da Analytic Hierarchy Process (AHP) na priorização dos esforços de pesquisa para maximizar o retorno de mercado.

The sugar kelp Saccharina latissima II: Recent advances in farming and application

The sugar kelp Saccharina latissima has received intense scientific attention over the last decades. In recent years, interest in cultivation of the species has strongly increased in the North Atlantic Ocean and the Eastern Pacific Ocean, driven by the great potential of S. latissima to be utilised for various industrial applications, including food, feed, and biomaterials. Accordingly, current research has focused on improving farming methods and technology, environmental impacts, and site selection. In addition, many studies have investigated the varying chemical composition of S. latissima, extraction of commercially interesting components, and the use of the biomass and its derived components in various applications. This review provides a comprehensive overview of farming and applications of S. latissima from the last 15 years. Additional insights on other research topics, such as ecology, physiology, biochemical and molecular biology of S. latissima, are given in the first review, “The sugar kelp Saccharina latissima I: recent advances in a changing climate” (Diehl et al. 2023).publishedVersio

Drivers of Change in Arctic Fjord Socio-ecological Systems: Examples from the European Arctic

Fjord systems are transition zones between land and sea, resulting in complex and dynamic environments. They are of particular interest in the Arctic as they harbour ecosystems inhabited by a rich range of species and provide many societal benefits. The key drivers of change in the European Arctic (i.e., Greenland, Svalbard, and Northern Norway) fjord socio-ecological systems are reviewed here, structured into five categories: cryosphere (sea ice, glacier mass balance, and glacial and riverine discharge), physics (seawater temperature, salinity, and light), chemistry (carbonate system, nutrients), biology (primary production, biomass, and species richness), and social (governance, tourism, and fisheries). The data available for the past and present state of these drivers, as well as future model projections, are analysed in a companion paper. Changes to the two drivers at the base of most interactions within fjords, seawater temperature and glacier mass balance, will have the most significant and profound consequences on the future of European Arctic fjords. This is because even though governance may be effective at mitigating/adapting to local disruptions caused by the changing climate, there is possibly nothing that can be done to halt the melting of glaciers, the warming of fjord waters, and all of the downstream consequences that these two changes will have. This review provides the first transdisciplinary synthesis of the interactions between the drivers of change within Arctic fjord socio-ecological systems. Knowledge of what these drivers of change are, and how they interact with one another, should provide more expedient focus for future research on the needs of adapting to the changing Arctic

Kinome rewiring reveals AURKA limits PI3K-pathway inhibitor efficacy in breast cancer.

Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest, possibly because of dynamic changes in cellular signaling that drive resistance and limit drug efficacy. Using a quantitative chemoproteomics approach, we mapped kinome dynamics in response to inhibitors of this pathway and identified signaling changes that correlate with drug sensitivity. Maintenance of AURKA after drug treatment was associated with resistance in breast cancer models. Incomplete inhibition of AURKA was a common source of therapy failure, and combinations of PI3K, AKT or mTOR inhibitors with the AURKA inhibitor MLN8237 were highly synergistic and durably suppressed mTOR signaling, resulting in apoptosis and tumor regression in vivo. This signaling map identifies survival factors whose presence limits the efficacy of targeted therapies and reveals new drug combinations that may unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements