Relevant Niche Research Articles

Effect of in vivo culture conditions on the proliferation and differentiation of rat adipose-derived stromal cells

Adipose-derived stromal cells (ADSCs) are promising stem cell sources for tissue engineering and cell-based therapy. However, long-term in vitro expansion of ADSCs impedes stemness maintenance, which is partly attributed to deprivation of their original microenvironment. Incompetent cells limit the therapeutic effects of ADSC-based clinical strategies. Therefore, reconstructing a more physiologically and physically relevant niche is an ideal strategy to address this issue and therefore facilitates the extensive application of ADSCs. Here, we transplanted separated ADSCs into local subcutaneous adipose tissues of nude mice as an in vivo cell culture model. We found that transplanted ADSCs maintained their primitive morphology and showed improved proliferation and delayed senescence compared to those of cells cultured in an incubator. Significantly increased expression of stemness-related markers and multilineage differentiation abilities were further observed in in vivo cultured ADSCs. Finally, sequencing revealed that genes whose expression differed between ADSCs obtained under in vivo and in vitro conditions were mainly located in the extracellular matrix and extracellular space and that these genes participate in regulating transcription and protein synthesis. Moreover, we found that an Egr1 signaling pathway might exert a crucial impact on controlling stemness properties. Our findings might collectively pave the way for ADSC-based applications.

Industry 4.0 technologies as a motivator for the circular economy in foodtechs: A stakeholder perspective

AbstractThis study aims to analyze the Industry 4.0 (I4.0) technologies as motivators to circular economy (CE) in the Brazilian foodtech sector via most relevant stakeholders. The study focuses on specific startups in the foodtech sector in the Brazilian context, offering a unique perspective on a relevant niche. It explores how I4.0 technologies are fundamental in the practices adopted by foodtechs, indicating an innovative approach aligned with technological trends. About the methodology, it was carried out through interviews with nine managers of foodtechs. Other sources of data collect have been used, such as reports, presentations, folders, products catalogs, consultations in companies sites, Instagram, Facebook, Linkedin, and videos on the Companies YouTube. The results show that: (i) the I4.0 technologies are fundamental in the practices adopted by the foodtechs; (ii) the CE being internalized, supported by I4.0; (iii) CE is made possible by gathering synergy and co‐participation from stakeholders which are strategic and relevant to foodtechs; (iv) innovation factor is present in the adoption of I4.0, in the operationalization of the practices of CE and in the production of synergy among the stakeholders relevant to foodtechs; (v) the creation of new markets is also a consequence of the adoption of I4.0, the adoption of CE and the articulation of stakeholders in the context analyzed; (vi) virtualize and regenerate are the most strengthened strategies at the sphere of the analyzed foodtechs; (vii) IoT, Big Data and integration of ubiquitous and intelligent components in supply chains are the highlighted artifacts in the making of CE practices at foodtechs levels; (viii) foodtechs of food producers have shown a greater synergy and articulation of stakeholders to the success of CE supported by I4.0. The contribution of the study is associated to the legitimation of I4.0 technologies as motivators to the adoption of CE and the engagement of stakeholders to successful circular business models. The study used a qualitative approach and collected data through interviews with nine startups in Brazil. Thematic analysis was employed to analyze the data. The limitations of the study include the small sample size and the focus on startups in one country. Future research should aim to explore the integration of I4.0 and the CE in larger samples, across multiple countries, and involving different types of organizations. Additionally, the study highlights the need for government support for startups in the form of funding, incentives, and regulations, as well as the importance of education and training programs to develop skills related to I4.0 and the CE. Overall, the research objectives are to understand the opportunities and challenges of I4.0 and CE integration in startups and to provide insights for policymakers and practitioners on how to foster sustainable business practices. The specificity of your study in exploring the relationship between the CE and I4.0 technologies in Brazilian foodtechs is a unique contribution. Many studies may focus on broader industries or international contexts, while yours delves into a specific, relevant niche.

Integrating digital and global transformations in forecasting regional growth: the MASST5 model

ABSTRACT During the past decade, world economic development was coupled with disruptive challenges. Among them, digitalisation and new forms of globalisation represent a potential threat for economic growth opportunities and for the future of labour markets. Digital transition calls for the assessment of the impact of robotisation and digitalisation on skill composition, employment levels, productivity and growth dynamics. In turn, the largest wave of globalisation after that taking place before the First World War caused, first, the emergence of global value chains and, more recently, their disintegration with partial mechanisms of reshoring, with consequences for growth and employment opportunities. All these challenges call for comprehensive approaches to their modelling. This paper presents the main advances introduced in the fifth generation of the MAcroeconomic, Sectoral, Social, Territorial (MASST5) model, which carved a relevant niche in the empirical literature on macro-econometric regional growth, and has now been strengthened to model future digitalisation transitions, as well as the national and regional breakdown of the way global value chains will reorganise. A longer time series, especially in the regional submodel, also allows one to take the major changes taking place in Europe following the 2007–08 financial crisis, and the 2020 COVID-induced contraction into account.

The global techno-economic potential of floating, closed-cycle ocean thermal energy conversion

Ocean Thermal Energy Conversion (OTEC) is an emerging renewable energy technology using the ocean’s heat to produce electricity. Given its early development stage, OTEC’s economics are still uncertain and there is no global assessment of its economic potential, yet. Here, we present the model pyOTEC that designs OTEC plants for best economic performance considering the spatiotemporally specific availability and seasonality of ocean thermal energy resources. We apply pyOTEC to more than 100 regions with technically feasible sites to obtain an order-of-magnitude estimation of OTEC’s global technical and economic potential. We find that OTEC’s global technical potential of 107 PWh/year could cover 11 PWh of 2019 electricity demand. At ≥ 120 MWgross, there are OTEC plants with Levelised Cost of Electricity (LCOE) below 15 US¢(2021)/kWh in 15 regions, including China, Brazil, and Indonesia. In the short-to-medium term, however, small island developing states are OTEC’s most relevant niche. Systems below 10 MWgross could fully and cost-effectively substitute Diesel generators on islands where that is more challenging with other renewables. With the global analysis, we also corroborate that most OTEC plants return the best economic performance if designed for worst-case surface and deep-sea water temperatures, which we further back up with a sensitivity analysis. We lay out pyOTEC’s limitations and fields for development to expand and refine our findings. The model as well as key data per region are publically accessible online.

Abstract 3069: Efficient establishment and utilization of a high-grade serous ovarian cancer organoid biobank

Abstract Extensive utilization of organoids from high-grade serous ovarian carcinoma (HGSOC), the most common and lethal ovarian cancer, has been hampered by low success rates of long-term culture and scarcity of fresh tumor material. Here we present the development of a novel method for efficient generation, expansion and use of HGSOC organoids from cryopreserved tumor material. First, we assessed commonly used organoid media components and found that supplements such as FGF-2, R-Spondin1, Wnt or Noggin had negative impact on the HGSOC organoid derivation. But further, we found that supplementation with FGF-4, which has not been used in cancer organoid culture before, is beneficial for HGSOC organoid growth. Through extensive testing of various supplements and their combinations, we designed two novel HGSOC organoid media formulations - Medium 1 (M1) and Medium 2 (M2). Using M1 and M2 enabled generation and long-term expansion of living HGSOC organoid biobank with markedly improved success rate than in previous reports (55% vs. 23-38%). The organoids were established from cryopreserved tumor material, demonstrating the feasibility of using frozen tissue biobanks for HGSOC organoid derivation. Overall, we generated a collection of 18 expandable HGSOC organoid lines from 11 patients, encompassing samples from different tissue sites and disease progression stages. We validated the organoids using whole-genome sequencing, immunohistochemistry and single-cell RNA sequencing and demonstrated that they are genetically and phenotypically representative of original patient samples over long-term culture. Based on available patient consents, we deposited 3 organoid lines in a publicly accessible biobank. Finally, we investigated whether organoid drug responses correlate to those observed earlier in the clinic in the corresponding patients. Organoid-based drug-response profiling of clinically used HGSOC drug collection was performed in 384-well microplate format. To explore whether growth conditions impact correlation between organoid drug responses and clinical response, we compared the organoid drug responses in the nutrient-rich M1/M2 growth media to the ones observed in human plasma-like medium (HPLM), supplemented with relevant niche factors from M1/M2. Organoid drug responses correlated with clinical treatment outcomes, but only for organoids maintained in HPLM (Spearman r = 0.987, p=0.007 in HPLM vs 0.607, p=0.167 in growth medium, n=7), highlighting the importance of culture conditions in organoid-based functional assays. Taken together, we introduce a resource for efficient development and use of HGSOC organoids from cryopreserved material in ovarian cancer research. Citation Format: Wojciech Senkowski, Laura Gall Mas, Matias M. Falco, Yilin Li, Kari Lavikka, Mette C. Kriegbaum, Jaana Oikkonen, Daria Bulanova, Elin J. Pietras, Karolin Voßgröne, Erdogan P. Erkan, Terese K. Høj, Mia K. Høg, Tarja Lamminen, Katja Kaipio, Anni Virtanen, Lars H. Engelholm, Pernille Christiansen, Eric Santoni-Rugiu, Kaisa Huhtinen, Olli Carpén, Johanna Hynninen, Sampsa Hautaniemi, Anna Vähärautio, Krister Wennerberg. Efficient establishment and utilization of a high-grade serous ovarian cancer organoid biobank [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3069.

International High-Tech Cluster as a Component of the Modern Concept of European Integration into the Scientific-Educational and Innovation Space

Ukraine requires modern industry for stable, inclusive and sustainable economic growth, which is based on the development and implementation of innovative technologies in Industry 4.0. High-tech productions and services have significant innovative potential. In order to develop them, Ukraine should make its profit of the opportunities of integration into the European Research Area as a tool for adapting the standards and norms of the European Union in the field of education, science and innovation. The work is aimed at substantiating scientific and methodological provisions for the formation of a relevant niche of Ukrainian-Polish scientific, educational and innovation space in the form of a pilot project to create an international high-tech cluster of Industry 4.0 with industrial enterprises and educational institutions. The scientific and methodical provisions of the experiment on the formation of the relevant niche of the Ukrainian-Polish scientific-educational and innovation space in the form of a pilot project to create an international high-tech cluster are substantiated on the example of the Pridneprovsky economic region. It is noted that its key actor can be recognized as a research center – an institution that is focused on performing specific functions in order to scientifically and innovatively ensure the modernization of industry regardless of administrative and territorial boundaries. The effective functioning of science parks is necessary to combine education, science and industry. The establishment of a representative office of the main stakeholder educational institution of the Polish side on the territory of the science park in Ukraine and a representative office of the Ukrainian research center in the Polish science park should provide both parties with PR support in the territory of the participating countries, access to market research, expert advice, investors and programmers communication.

Effects of bird species-level environmental preference on landscape-level richness-heterogeneity relationships

The niche-based argument that species are filtered from environments in which they cannot sustain viable populations is the basis of the Richness-Heterogeneity Relationship (RHR). However, the multi-dimensionality of niches suggests that the RHR may take different shapes along different environmental axes, with potential confounding effects if filtering along the axes is not equally strong. Here, we explore how different structural and landscape variables drive the RHR as the accumulative outcome of environmental preferences at the species-level while considering the intercorrelation between heterogeneity levels along three niche axes. We used occurrence data of avifauna from 226 sites situated along a grassland-to-woodland gradient in a Midwestern USA study area. In each site, we quantified horizontal (habitat cover type), vertical (vegetation height structure), and spatial (habitat configuration) heterogeneity and explored the shape of the observed RHR at the landscape scale, as well as the correlations among heterogeneity levels at different axes. We then fitted species distribution models to environmental variables from the three axes separately and compared the stacked probabilities of occurrences of all species to the observed species richness. We found that predictions of richness patterns improved when more than one heterogeneity axis was included in RHR models, and that habitat suitability along different axes is not equally strong. Furthermore, a unimodal RHR along the vegetation height axis, which the species distribution models revealed to be a weak predictor for most species, may arise through intercorrelation with heterogeneity along the two other axes, along which we recorded stronger signals of environmental preference at the species level. Our results emphasize the importance of selecting relevant niche axes in studies of species richness patterns because ultimately, these patterns reflect the various environmental preferences of individual species.

Insights into organic wine consumption: behaviour, segmentation and attribute non-attendance

Several studies have focused on the behaviour of consumers towards organic wine, finding varying and sometimes conflicting results. Some scholars have noted that consumers may perceive wine labelled as organic to be of a lower quality, whereas others have found that consumers are willing to pay a premium price for it. Starting from these discrepancies found in the literature, this study seeks to investigate how the organic certification influences consumers when purchasing a bottle of red wine, evaluating the possible presence of attribute non-attendance (ANA) behaviour. A choice experiment was carried out on a sample of Italian wine consumers. Findings highlight that although, on average, consumers do not prefer organic wine, there is a relevant niche in the market consisting of consumers who benefit from purchasing it. Moreover, we have found that the majority of the sample ignores the organic attribute when choosing a bottle of wine, which reveals ANA behaviour.

A Unified Framework for Personalizing Product Rankings

We study the extent to which consumers benefit from personalized product suggestions offered by online retailers. Using data from a large-scale randomized experiment conducted by a major online retailer, we show that personalized product rankings induce users to purchase a greater variety of items relative to non-personalized bestseller-based rankings. To study whether users benefit from this shift in demand, we estimate an empirical choice model and use it to measure the effect of personalization on consumer surplus. Our model captures flexible taste heterogeneity by combining a standard consideration model with a latent factorization approach from computer science. This combination enables us to estimate users' tastes from data on both search histories and personalized rankings, while also recognizing that user histories are confounded by the prominence of displayed items. We estimate users' tastes and show that personalized rankings increase consumer surplus by 30% for the average user. This effect arises primarily because personalization makes users with niche tastes more likely to discover relevant niche items. Without personalization, the retailer would only offer 25% of its current assortment because most of these niche items would never find their audience.

Targeting TRPV1 on cellular plasticity regulated by Ovol 2 and Zeb 1 in hepatocellular carcinoma

The landscape of cellular plasticity and sources with relevant niche signals in hepatocellular carcinoma is still obscure. Transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel, is involved in a variety of malignancies and overexpressed in hepatocellular carcinoma (HCC). We have investigated the role of TRPV1 in HCC from different angles by various experimental techniques, such as in vivo and in vitro experiments, and by bioinformatics analysis of data from genetic models induced by diethylnitrosamine (DEN), mice samples and human HCC samples. We find that TRPV1 knockout promotes to hepatocarcinogenesis and deconstructs the portal triad adjacent to tumor border that is contributed by originations of tumor initiating cells and biliary cells. Epithelial to mesenchymal transition (EMT) is involved and transcription factors Ovol2 and Zeb1 coordinated with Sox 10 drive gene expression in the event which is also confirmed by the expression of these proteins in human HCC samples. Treatment with TRPV1 agonist Capsaicin inhibits the growth of HCC cells in xenograft models. Our findings demonstrate that TRPV1 is a potential therapeutic target in human HCC and exerts effects on cellular plasticity with modulation of Ovol2, Zeb1 and Sox10.

Imaging-Based Screen Identifies Laminin 411 as a Physiologically Relevant Niche Factor with Importance for i-Hep Applications.

SummaryUse of hepatocytes derived from induced pluripotent stem cells (i-Heps) is limited by their functional differences in comparison with primary cells. Extracellular niche factors likely play a critical role in bridging this gap. Using image-based characterization (high content analysis; HCA) of freshly isolated hepatocytes from 17 human donors, we devised and validated an algorithm (Hepatocyte Likeness Index; HLI) for comparing the hepatic properties of cells against a physiological gold standard. The HLI was then applied in a targeted screen of extracellular niche factors to identify substrates driving i-Heps closer to the standard. Laminin 411, the top hit, was validated in two additional induced pluripotent stem cell (iPSC) lines, primary tissue, and an in vitro model of α1-antitrypsin deficiency. Cumulatively, these data provide a reference method to control and screen for i-Hep differentiation, identify Laminin 411 as a key niche protein, and underscore the importance of combining substrates, soluble factors, and HCA when developing iPSC applications.

Hematopoietic Niche - Exploring Biomimetic Cues to Improve the Functionality of Hematopoietic Stem/Progenitor Cells.

The adult bone marrow (BM) niche is a complex entity where a homeostatic hematopoietic system is maintained through a dynamic crosstalk between different cellular and non-cellular players. Signaling mechanisms triggered by cell-cell, cell-extracellular matrix (ECM), cell-cytokine interactions, and local microenvironment parameters are involved in controlling quiescence, self-renewal, differentiation, and migration of hematopoietic stem/progenitor cells (HSPC). A promising strategy to more efficiently expand HSPC numbers and tune their properties ex vivo is to mimic the hematopoietic niche through integration of adjuvant stromal cells, soluble cues, and/or biomaterial-based approaches in HSPC culture systems. Particularly, mesenchymal stem/stromal cells (MSC), through their paracrine activity or direct contact with HSPC, are thought to be a relevant niche player, positioning HSPC-MSC co-culture as a valuable platform to support the ex vivo expansion of hematopoietic progenitors. To improve the clinical outcome of hematopoietic cell transplantation (HCT), namely when the available HSPC are present in a limited number such is the case of HSPC collected from umbilical cord blood (UCB), ex vivo expansion of HSPC is required without eliminating the long-term repopulating capacity of more primitive HSC. Here, we will focus on depicting the characteristics of co-culture systems, as well as other bioengineering approaches to improve the functionality of HSPC ex vivo.

The Role of Governmental Venture Capital in the Venture Capital Ecosystem: An Organizational Ecology Perspective

We use the theory of organizational ecology to study how governmental venture capital (GVC) affects the investment behavior of private venture capital (PVC). Because of its objectives and dominant competencies, GVC is a unique organizational species that occupies a different niche than PVC. GVC is conceived to establish mutualistic relations with PVC. Accordingly, the greater the presence of GVC in a venture capital (VC) ecosystem, the more PVC investors should be attracted toward GVC’s niche. We consider several relevant niche dimensions at the company (age and size), industry (biotechnology), and regional (competitiveness) levels. Our analysis of 1,239 PVC investments in Europe confirms most of our predictions.

Individuals and Sustainability: A Review of Micro-Level Social and Environmental Issues Research

We comprehensively review the empirical research pertaining to individual-level sustainability issues within the organizational context. Our search of papers published from 2005 to the present involved 50 leading management and relevant niche journals, and uncovered 64 studies meeting our search criteria. We systematically document and structure the relevant research, and analyze the key trends and themes emerging from this work. We further asses the current state of knowledge to determine what evidence-based conclusions can be drawn to inform sustainable management practice. Finally, we identify knowledge gaps and suggest productive opportunities for future research. Our review provides a reference resource for micro-level sustainability scholars and those interested in more effectively managing employees for sustainability.

Endosteal-like extracellular matrix expression on melt electrospun written scaffolds.

This work is motivated by the recent interest in melt electrospinning writing, a 3D printing technique used to produce porous scaffolds for biomedical applications in regenerative medicine. Our team has been among the pioneers in building a new class of melt electrospinning devices for scaffold-based tissue engineering. These scaffolds allow structural support for various cell types to invade and deposit their own ECM, mimicking a characteristic 3D microenvironment for experimental studies. We used melt electrospun written polycaprolactone scaffolds to develop an endosteal bone-like tissue that promotes the growth of HSCs. We combine tissue engineering concepts with cell biology and stem cell research to design a physiologically relevant niche that is of prime interest to the scientific community.

Regeneration of hair and other skin appendages: A microenvironment-centric view.

Advances in skin regeneration have resulted in techniques and products that have allowed regeneration of both the dermis and epidermis. Yet complete skin regeneration requires the adnexal skin structures. Thus it is crucial to understand the regenerative potential of hair follicles where genetic, nutritional, and hormonal influences have important effects and are critical for skin regeneration. The follicular stem cell niche serves as an anatomical compartment, a structural unit, a functional integrator, and a dynamic regulator necessary to sustain internal homeostasis and respond to outside stimuli. In particular, mechanics such as pressure, compression, friction, traction, stretch, shear, and mechanical wounding can influence hair loss or growth. Relevant niche signaling pathways such as Wnt, bone morphogenetic protein, fibroblast growth factor, Shh, and Notch may yield potential targets for therapeutic interventions.

Influence of Different Components of the Tumor Microenvironment on Human Patient-Derived Lymphoma Cell Engraftment in Immmunodeficient Mice

Patient-derived xenografts (PDX) have become reliable tools for preclinical research for many types of cancer. We recently reported the establishment of 4 human diffuse-large B-cell lymphoma (DLBCL) PDX in mice arising from patient prostate carcinoma tissue (Wetterauer,C. et al. 2015). All PDX were EBV associated and of ABC subtype as determined by the new algorithm of Choi et al. 2009. In contrast, none of the donor patients showed clinical or histological evidence of lymphoma disease. To address the question why lymphoma engraftment takes place in immunodeficient mice whereas patients do not show clinical evidence of disease, we compared growth behavior of the DLBCL PDX in 4 different mouse strains harboring different immunological deficiencies. Furthermore using 3 different implantation routes the dissemination behavior of these models into different immunological niches was evaluated. Results were compared to a similar study carried out with an EBV negative DLBCL PDX of a secondary, cerebral lymphoma (ABC-subtype).None of 4 EBV+ DLBCL PDX showed tumor growth after implantation in NMRI nu/nu (B- cells+, T cells-, NK cells+, n=5 mice/PDX) or 1147-F mice (B cells-, T cells+, NK cells+ n=5 mice/PDX). Subcutaneous implantation into NOD/SCID mice (B cells-, T cells-, NK cells+ n=5 mice/PDX) revealed tumor growth for 2 of 4 lymphomas displaying take rates of 80% (4 out of 5 mice) and 100% (5 out of 5 mice) within one model. Infiltration of murine NK cells in tumor tissue was determined by IHC (analyses ongoing). All 4 EBV+ lymphoma models showed stable growth in NOG mice (B cells-, T cells-, NK cells- n= 10 - 12 mice/PDX) with a take rate of 100% and an average passaging time of 20 days, ranging from 14 to 26 depending on the specific model. Taken together these results indicate that tumor growth of EBV+ lymphomas in mice depends on the NK cell activity as well as the B- and T cells status of the recipient mouse. These cell populations control tumor engraftment in mice, which might explain the absence of lymphoma disease in donor patients. In contrast the PDX of a clinically apparent EBV- DLBCL patient was able to circumvent NK cell block in NMRI nu/nu mice and showed similar take rates (100%, 5 out of 5 engrafted mice) but prolonged passaging times (35 days) as compared to NOG (26 days).Comparison of tumor cell engraftment after subcutaneous (s.c.), intravenous (i.v.) and intratibial (i.t.) injection of tumor cells in NOG mice revealed disseminated tumor growth for the EBV- DLBCL PDX exclusively when injected i.v. or i.t.. After subcutaneous implantation of lymphoma material, no tumor cells could be detected by flow cytometry or IHC in lymph nodes, blood, spleen, brain, liver, lung or bone marrow of recipient mice. However, lymphoma cells could be detected in liver and bone marrow of all (n= 8) i.v. and i.t. injected mice. Currently we are analyzing the dissemination behavior of the EBV+ lymphomas after injection into the different immunological niches as described above.In summary these data highlight the importance of the tumor microenvironment in lymphoma engraftment and dissemination in vivo. Accordingly we could show for our EBV associated lymphoma models that NK-, T- and B cell population control engraftment in vivo and are possibly involved in controlling EBV+ transformed lymphatic cells in patients. Furthermore, we showed that injection into the biologically relevant niche enables lymphoma cells to form multiple tumor nodules in distinct organs in vivo. These models contribute to a better understanding of the interplay between lymphoma cells and their microenvironment. They will thereby facilitate the discovery of new targets for innovative anti-lymphoma treatment strategies. DisclosuresTschuch:Oncotest GmbH: Employment. Klingner:Oncotest GmbH: Employment. Lenhard:Oncotest GmbH: Employment. Haapaniemi:Biositehisto Oy: Employment. Schueler:Oncotest GmbH: Employment.

SRNA-Mediated Regulation of P-Fimbriae Phase Variation in Uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) are capable of occupying physiologically distinct intracellular and extracellular niches within the urinary tract. This feat requires the timely regulation of gene expression and small RNAs (sRNAs) are known to mediate such rapid adjustments in response to changing environmental cues. This study aimed to uncover sRNA-mediated gene regulation in the UPEC strain UTI89, during infection of bladder epithelial cells. Hfq is an RNA chaperone known to facilitate and stabilize sRNA and target mRNA interactions with bacterial cells. The co-immunoprecipitation and high throughput RNA sequencing of Hfq bound sRNAs performed in this study, revealed distinct sRNA profiles in UPEC in the extracellular and intracellular environments. Our findings emphasize the importance of studying regulatory sRNAs in a biologically relevant niche. This strategy also led to the discovery of a novel virulence-associated trans-acting sRNA—PapR. Deletion of papR was found to enhance adhesion of UTI89 to both bladder and kidney cell lines in a manner independent of type-1 fimbriae. We demonstrate PapR mediated posttranscriptional repression of the P-fimbriae phase regulator gene papI and postulate a role for such regulation in fimbrial cross-talk at the population level in UPEC. Our results further implicate the Leucine responsive protein (LRP) as a transcriptional activator regulating PapR expression. Our study reports, for the first time, a role for sRNAs in regulation of P-fimbriae phase variation and emphasizes the importance of studying pathogenesis-specific sRNAs within a relevant biological niche.

Ecological filtering or random extinction? Beta‐diversity patterns and the importance of niche‐based and neutral processes following habitat loss

Although both niche‐based and neutral processes are involved in community assembly, most models on the effects of habitat loss are stochastic, assuming neutral communities mainly affected by ecological drift and random extinction. Given that habitat loss is considered the most important driver of the current biodiversity crisis, unraveling the processes underlying the effects of habitat loss is critical from both a theoretical and an applied perspective. Here we unveil the importance of niche‐based and neutral processes to species extinction and community assembly across a gradient of habitat loss, challenging the predictions of neutral models. We draw on a large dataset containing the distribution of 3653 individuals of 42 species, representing 35% of the small mammal species of the Atlantic Forest hotspot, obtained in 68 sites across three continuously‐forested landscapes and three adjacent 10 000‐ha fragmented landscapes differing in the amount of remaining forest (50%, 30% and 10%). By applying a null‐model approach, we investigated β‐diversity patterns by detecting deviations of observed community similarity from the similarity between randomly assembled communities. Species extinction following habitat loss was decidedly non‐random, in contrast to the notion that fragmented communities are mainly driven by ecological drift. Instead, habitat loss led to a strong biotic homogenization. Moreover, species composition changed abruptly at the same level of landscape‐scale habitat loss that has already been associated with a drastic decline in species richness. Habitat loss, as other anthropogenic disturbances, can thus be seen as a strong ecological filter that increases (rather than decreases) the importance of deterministic processes in community assembly. As such, critical advances for the development of conservation science lie on the incorporation of the relevant niche traits associated with extinction proneness into models of habitat loss. The results also underscore the fundamental importance of pro‐active measures to prevent human‐modified landscapes surpassing critical ecological thresholds.

The Call of the Crowd: Event Participation in Location-Based Social Services

Understanding the social and behavioral forces behind event participation is not only interesting from the viewpoint of social science, but also has important applications in the design of personalized event recommender systems.This paper takes advantage of data from a widely used location-based social network, Foursquare, to analyze event patterns in three metropolitan cities. We put forward several hypotheses on the motivating factors of user participation and confirm that social aspects play a major role in determining the likelihood of a user to participate in an event. While an explicit social filtering signal accounting for whether friends are attending dominates the factors, the popularity of an event proves to also be a strong attractor. Further, we capture an implicit social signal by performing random walks in a high dimensional graph that encodes the place type preferences of friends and that proves especially suited to identify relevant niche events for users. Our findings on the extent to which the various temporal, spatial and social aspects underlie users' event preferences lead us to further hypothesize that a combination of factors better models users' event interests. We verify this through a supervised learning framework. We show that for one in three users in London and one in five users in New York and Chicago it identifies the exact event the user would attend among the pool of suggestions.