Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts.

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A global-scale expert assessment of drivers and risks associated with pollinator decline.

Pollinator decline has attracted global attention and substantial efforts are underway to respond through national pollinator strategies and action plans. These policy responses require clarity on what is driving pollinator decline and what risks it generates for society in different parts of the world. Using a formal expert elicitation process, we evaluated the relative regional and global importance of eight drivers of pollinator decline and ten consequent risks to human well-being. Our results indicate that global policy responses should focus on reducing pressure from changes in land cover and configuration, land management and pesticides, as these were considered very important drivers in most regions. We quantify how the importance of drivers and risks from pollinator decline, differ among regions. For example, losing access to managed pollinators was considered a serious risk only for people in North America, whereas yield instability in pollinator-dependent crops was classed as a serious or high risk in four regions but only a moderate risk in Europe and North America. Overall, perceived risks were substantially higher in the Global South. Despite extensive research on pollinator decline, our analysis reveals considerable scientific uncertainty about what this means for human society.University of Reading’s Building Outstanding Impact Support Programm

Characteristics, Distribution and Persistence of Thin Layers Over a 48 Hour Period

The biological and physical processes contributing to planktonic thin layer dynamics were examined in a multidisciplinary study conducted in East Sound, Washington, USA between June 10 and June 25, 1998. The temporal and spatial scales characteristic of thin layers were determined using a nested sampling strategy utilizing 4 major types of platforms: (1) an array of 3 moored acoustical instrument packages and 2 moored optical instrument packages that recorded distributions and intensities of thin layers; (2) additional stationary instrumentation deployed outside the array comprised of meteorological stations, wave-tide gauges, and thermistor chains; (3) a research vessel anchored 150 m outside the western edge of the array; (4) 2 mobile vessels performing basin-wide surveys to define the spatial extent of thin layers and the physical hydrography of the Sound. We observed numerous occurrences of thin layers that contained locally enhanced concentrations of material; many of the layers persisted for intervals of several hours to a few days. More than one persistent thin layer may be present at any one time, and these spatially distinct thin layers often contain distinct plankton assemblages. The results suggest that the species or populations comprising each distinct thin layer have responded to different sets of biological and/or physical processes. The existence and persistence of planktonic thin layers generates extensive biological heterogeneity in the water column and may be important in maintaining species diversity and overall community structure

BarA-UvrY Two-Component System Regulates Virulence of Uropathogenic E. coli CFT073

Uropathogenic Escherichia coli (UPEC), a member of extraintestinal pathogenic E. coli, cause ∼80% of community-acquired urinary tract infections (UTI) in humans. UPEC initiates its colonization in epithelial cells lining the urinary tract with a complicated life cycle, replicating and persisting in intracellular and extracellular niches. Consequently, UPEC causes cystitis and more severe form of pyelonephritis. To further understand the virulence characteristics of UPEC, we investigated the roles of BarA-UvrY two-component system (TCS) in regulating UPEC virulence. Our results showed that mutation of BarA-UvrY TCS significantly decreased the virulence of UPEC CFT073, as assessed by mouse urinary tract infection, chicken embryo killing assay, and cytotoxicity assay on human kidney and uroepithelial cell lines. Furthermore, mutation of either barA or uvrY gene reduced the production of hemolysin, lipopolysaccharide (LPS), proinflammatory cytokines (TNF-α and IL-6) and chemokine (IL-8). The virulence phenotype was restored similar to that of wild-type by complementation of either barA or uvrY gene in trans. In addition, we discussed a possible link between the BarA-UvrY TCS and CsrA in positively and negatively controlling virulence in UPEC. Overall, this study provides the evidences for BarA-UvrY TCS regulates the virulence of UPEC CFT073 and may point to mechanisms by which virulence regulations are observed in different ways may control the long-term survival of UPEC in the urinary tract

ADAM15 mediates upregulation of Claudin-1 expression in breast cancer cells

A Disintegrin and Metalloproteinase-15 (ADAM15) is a transmembrane protein involved in protein ectodomain shedding, cell adhesion and signalling. We previously cloned and characterised alternatively spliced variants of ADAM15 that differ in their intracellular domains and demonstrated correlation of the expression of specific variants with breast cancer prognosis. In this study we have created isogenic cell panels (MDA-MB-231 and MCF-7) expressing five ADAM15 variants including wildtype and catalytically inactive forms. The expression of ADAM15 isoforms in MDA-MB-231 cells led to cell clustering to varying degree, without changes in EMT markers vimentin, slug and E-cadherin. Analysis of tight junction molecules revealed ADAM15 isoform specific, catalytic function dependent upregulation of Claudin-1. The expression of ADAM15A, and to a lesser degree of C and E isoforms led to an increase in Claudin-1 expression in MDA-MB-231 cells, while ADAM15B had no effect. In MCF-7 cells, ADAM15E was the principal variant inducing Claudin-1 expression. Sh-RNA mediated down-regulation of ADAM15 in ADAM15 over-expressing cells reduced Claudin-1 levels. Additionally, downregulation of endogenous ADAM15 expression in T47D cells by shRNA reduced endogenous Claudin-1 expression confirming a role for ADAM15 in regulating Claudin-1 expression. The PI3K/Akt/mTOR pathway was involved in regulating Claudin-1 expression downstream of ADAM15. Immunofluorescence analysis of MDA-MB-231 ADAM15A expressing cells showed Claudin-1 at cell-cell junctions, in the cytoplasm and nuclei. ADAM15 co-localised with Claudin-1 and ZO1 at cell-cell junctions. Immunoprecipitation analysis demonstrated complex formation between ADAM15 and ZO1/ZO2. These findings highlight the importance of ADAM15 Intra Cellular Domain-mediated interactions in regulating substrate selection and breast cancer cell phenotype

Extracellular cleavage and shedding of P-cadherin: a mechanism underlying the invasive behaviour of breast cancer cells

Cell-cell adhesion is an elementary process in normal epithelial cellular architecture. Several studies have shown the role mediated by cadherins in this process, besides their role in the maintenance of cell polarity, differentiation and cell growth. However, during tumour progression, these molecules are frequently altered. In breast cancer, tumours that overexpress P-cadherin usually present a high histological grade, show decreased cell polarity and are associated with worse patient survival. However, little is known about how this protein dictates the very aggressive behaviour of these tumours. To achieve this goal, we set up two breast cancer cell models, where P-cadherin expression was differently modulated and analysed in terms of cell invasion, motility and migration. We show that P-cadherin overexpression, in breast cancer cells with wild-type E-cadherin, promotes cell invasion, motility and migration. Moreover, we found that the overexpression of P-cadherin induces the secretion of matrix metalloproteases, specifically MMP-1 and MMP-2, which then lead to P-cadherin ectodomain cleavage. Further, we showed that soluble P-cadherin fragment is able to induce in vitro invasion of breast cancer cells. Overall, our results contribute to elucidate the mechanism underlying the invasive behaviour of P-cadherin expressing breast tumours.scientific project (POCI/BIA-BCM/59252/2004) financed by the Portuguese Science and Technology Foundation (FCT). FCT also provided research grants as follows: Programa Ciência 2007 (FCT) for Joana Paredes, and PhD research grants for Ana Sofia Ribeiro (SFRH/BD/36096/2007) and André Albergaria (SFRH/BD/15316/2005)

Social Transfer of Pathogenic Fungus Promotes Active Immunisation in Ant Colonies

Social contact with fungus-exposed ants leads to pathogen transfer to healthy nest-mates, causing low-level infections. These micro-infections promote pathogen-specific immune gene expression and protective immunization of nest-mates

Plasminogen binding and activation at the breast cancer cell surface: the integral role of urokinase activity

INTRODUCTION: The regulation of extracellular proteolytic activity via the plasminogen activation system is complex, involving numerous activators, inhibitors, and receptors. Previous studies on monocytic and colon cell lines suggest that plasmin pre-treatment can increase plasminogen binding, allowing the active enzyme to generate binding sites for its precursor. Other studies have shown the importance of pre-formed receptors such as annexin II heterotetramer. However, few studies have used techniques that exclusively characterise cell-surface events and these mechanisms have not been investigated at the breast cancer cell surface. METHODS: We have studied plasminogen binding to MCF-7 in which urokinase plasminogen activator receptor (uPAR) levels were upregulated by PMA (12-O-tetradecanoylphorbol-13-acetate) stimulation, allowing flexible and transient modulation of cell-surface uPA. Similar experiments were also performed using MDA-MB-231 cells, which overexpress uPAR/uPA endogenously. Using techniques that preserve cell integrity, we characterise the role of uPA as both a plasminogen receptor and activator and quantify the relative contribution of pre-formed and cryptic plasminogen receptors to plasminogen binding. RESULTS: Cell-surface plasminogen binding was significantly enhanced in the presence of elevated levels of uPA in an activity-dependent manner and was greatly attenuated in the presence of the plasmin inhibitor aprotinin. Pre-formed receptors were also found to contribute to increased plasminogen binding after PMA stimulation and to co-localise with uPA/uPAR and plasminogen. Nevertheless, a relatively modest increase in plasminogen-binding capacity coupled with an increase in uPA led to a dramatic increase in the proteolytic capacity of these cells. CONCLUSION: We show that the majority of lysine-dependent plasminogen binding to breast cancer cells is ultimately regulated by plasmin activity and is dependent on the presence of significant levels of active uPA. The existence of a proteolytic positive feedback loop in plasminogen activation has profound implications for the ability of breast cancer cells expressing high amounts of uPA to accumulate a large proteolytic capacity at the cell surface, thereby conferring invasive potential

Desmoglein 2 mutant mice develop cardiac fibrosis and dilation

Desmosomes are cell–cell adhesion sites and part of the intercalated discs, which couple adjacent cardiomyocytes. The connection is formed by the extracellular domains of desmosomal cadherins that are also linked to the cytoskeleton on the cytoplasmic side. To examine the contribution of the desmosomal cadherin desmoglein 2 to cardiomyocyte adhesion and cardiac function, mutant mice were prepared lacking a part of the extracellular adhesive domain of desmoglein 2. Most live born mutant mice presented normal overall cardiac morphology at 2 weeks. Some animals, however, displayed extensive fibrotic lesions. Later on, mutants developed ventricular dilation leading to cardiac insufficiency and eventually premature death. Upon histological examination, cardiomyocyte death by calcifying necrosis and replacement by fibrous tissue were observed. Fibrotic lesions were highly proliferative in 2-week-old mutants, whereas the fibrotic lesions of older mutants showed little proliferation indicating the completion of local muscle replacement by scar tissue. Disease progression correlated with increased mRNA expression of c-myc, ANF, BNF, CTGF and GDF15, which are markers for cardiac stress, remodeling and heart failure. Taken together, the desmoglein 2-mutant mice display features of dilative cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy, an inherited human heart disease with pronounced fibrosis and ventricular arrhythmias that has been linked to mutations in desmosomal proteins including desmoglein 2