462 research outputs found

    Introduction

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    The Effects of Avian Influenza News on Consumer Purchasing Behavior: A Case Study of Italian Consumers' Retail Purchases

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    To better understand how information about potential health hazards influences food demand, this case study examines consumers’ responses to newspaper articles on avian influenza, informally referred to as bird flu. The focus here is on the response to bird flu information in Italy as news about highly pathogenic H5N1 avian influenza (HPAI H5N1) unfolded in the period October 2004 through October 2006, beginning after reports of the first outbreaks in Southeast Asia and extending beyond the point at which outbreaks were reported in Western Europe. Estimated poultry demand, as influenced by the volume of newspaper reports on bird flu, reveals the magnitude and duration of newspaper articles’ impacts on consumers’ food choices. Larger numbers of bird flu news reports led to larger reductions in poultry purchases. Most impacts were of limited duration, and all began to diminish within 5 weeks.Avian influenza, bird flu, consumer behavior, food safety, poultry sales and consumption, risk perception and response, Agricultural and Food Policy, Health Economics and Policy, Institutional and Behavioral Economics, International Relations/Trade,

    Transcription Factor Efg1 Shows a Haploinsufficiency Phenotype in Modulating the Cell Wall Architecture and Immunogenicity of Candida albicans

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    The Candida albicans transcription factor Efg1 is known to be involved in many different cellular processes, including morphogenesis, general metabolism, and virulence. Here we show that besides its manifold roles, Efg1 also has a prominent effect on cell wall structure and composition, strongly affecting the structural glucan part. Deletion of only one allele of EFG1 already results in severe phenotypes for cell wall biogenesis, comparable to those with deletion of both alleles, indicative of a severe haploinsufficiency for EFG1. The observed defects in structural setup of the cell wall, together with previously reported alterations in expression of cell surface proteins, result in altered immunogenic properties of strains with compromised Efg1 function. This is shown by interaction studies with macrophages and primary dendritic cells. The structural changes in the cell wall carbohydrate meshwork presented here, together with the manifold changes in cell wall protein composition and metabolism reported in other studies, contribute to the altered immune response mounted by innate immune cells and to the altered virulence phenotypes observed for strains lacking EFG1

    The Response of Big Sagebrush (\u3ci\u3eArtemisia tridentata\u3c/i\u3e) to Interannual Climate Variation Changes Across Its Range

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    Understanding how annual climate variation affects population growth rates across a species\u27 range may help us anticipate the effects of climate change on species distribution and abundance. We predict that populations in warmer or wetter parts of a species\u27 range should respond negatively to periods of above average temperature or precipitation, respectively, whereas populations in colder or drier areas should respond positively to periods of above average temperature or precipitation. To test this, we estimated the population sensitivity of a common shrub species, big sagebrush (Artemisia tridentata), to annual climate variation across its range. Our analysis includes 8,175 observations of year‐to‐year change in sagebrush cover or production from 131 monitoring sites in western North America. We coupled these observations with seasonal weather data for each site and analyzed the effects of spring through fall temperatures and fall through spring accumulated precipitation on annual changes in sagebrush abundance. Sensitivity to annual temperature variation supported our hypothesis: years with above average temperatures were beneficial to sagebrush in colder locations and detrimental to sagebrush in hotter locations. In contrast, sensitivity to precipitation did not change significantly across the distribution of sagebrush. This pattern of responses suggests that regional abundance of this species may be more limited by temperature than by precipitation. We also found important differences in how the ecologically distinct subspecies of sagebrush responded to the effects of precipitation and temperature. Our model predicts that a short‐term temperature increase could produce an increase in sagebrush cover at the cold edge of its range and a decrease in cover at the warm edge of its range. This prediction is qualitatively consistent with predictions from species distribution models for sagebrush based on spatial occurrence data, but it provides new mechanistic insight and helps estimate how much and how fast sagebrush cover may change within its range

    Promoting bioengineered tooth innervation using nanostructured and hybrid scaffolds

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    The innervation of teeth mediated by axons originating from the trigeminal ganglia is essential for their function and protection. Immunosuppressive therapy using Cyclosporine A (CsA) was found to accelerate the innervation of transplanted tissues and particularly that of bioengineered teeth. To avoid the CsA side effects, we report in this study the preparation of CsA loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles, their embedding on polycaprolactone (PCL)-based scaffolds and their possible use as templates for the innervation of bioengineered teeth. This PCL scaffold, approved by the FDA and capable of mimicking the extracellular matrix, was obtained by electrospinning and decorated with CsA-loaded PLGA nanoparticles to allow a local sustained action of this immunosuppressive drug. Dental re-associations were co-implanted with a trigeminal ganglion on functionalized scaffolds containing PLGA and PLGA/cyclosporine in adult ICR mice during 2 weeks. Histological analyses showed that the designed scaffolds did not alter the teeth development after in vivo implantation. The study of the innervation of the dental re-associations by indirect immunofluorescence and transmission electron microscopy (TEM), showed that 88.4% of the regenerated teeth were innervated when using the CsA-loaded PLGA scaffold. The development of active implants thus allows their potential use in the context of dental engineering. Statement of Significance Tooth innervation is essential for their function and protection and this can be promoted in vivo using polymeric scaffolds functionalized with immunosuppressive drug-loaded nanoparticles. Immunosuppressive therapy using biodegradable nanoparticles loaded with Cyclosporine A was found to accelerate the innervation of bioengineered teeth after two weeks of implantation

    The Candida albicans Histone Acetyltransferase Hat1 Regulates Stress Resistance and Virulence via Distinct Chromatin Assembly Pathways

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    Human fungal pathogens like Candida albicans respond to host immune surveillance by rapidly adapting their transcriptional programs. Chromatin assembly factors are involved in the regulation of stress genes by modulating the histone density at these loci. Here, we report a novel role for the chromatin assembly-associated histone acetyltransferase complex NuB4 in regulating oxidative stress resistance, antifungal drug tolerance and virulence in C. albicans. Strikingly, depletion of the NuB4 catalytic subunit, the histone acetyltransferase Hat1, markedly increases resistance to oxidative stress and tolerance to azole antifungals. Hydrogen peroxide resistance in cells lacking Hat1 results from higher induction rates of oxidative stress gene expression, accompanied by reduced histone density as well as subsequent increased RNA polymerase recruitment. Furthermore, hat1Delta/Delta cells, despite showing growth defects in vitro, display reduced susceptibility to reactive oxygen-mediated killing by innate immune cells. Thus, clearance from infected mice is delayed although cells lacking Hat1 are severely compromised in killing the host. Interestingly, increased oxidative stress resistance and azole tolerance are phenocopied by the loss of histone chaperone complexes CAF-1 and HIR, respectively, suggesting a central role for NuB4 in the delivery of histones destined for chromatin assembly via distinct pathways. Remarkably, the oxidative stress phenotype of hat1Delta/Delta cells is a species-specific trait only found in C. albicans and members of the CTG clade. The reduced azole susceptibility appears to be conserved in a wider range of fungi. Thus, our work demonstrates how highly conserved chromatin assembly pathways can acquire new functions in pathogenic fungi during coevolution with the host

    Potential implantable nanofibrous biomaterials combined with stem cells for subchondral bone regeneration

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    The treatment of osteochondral defects remains a challenge. Four scaffolds were produced using Food and Drug Administration (FDA)-approved polymers to investigate their therapeutic potential for the regeneration of the osteochondral unit. Polycaprolactone (PCL) and poly(vinyl-pyrrolidone) (PVP) scaffolds were made by electrohydrodynamic techniques. Hydroxyapatite (HAp) and/or sodium hyaluronate (HA) can be then loaded to PCL nanofibers and/or PVP particles. The purpose of adding hydroxyapatite and sodium hyaluronate into PCL/PVP scaffolds is to increase the regenerative ability for subchondral bone and joint cartilage, respectively. Humanbone marrow-derived mesenchymal stem cells (hBM-MSCs) were seeded on these biomaterials. The biocompatibility of these biomaterials in vitro and in vivo, as well as their potential to support MSC differentiation under specific chondrogenic or osteogenic conditions, were evaluated. We show here that hBM-MSCs could proliferate and differentiate both in vitro and in vivo on these biomaterials. In addition, the PCL-HAp could effectively increase the mineralization and induce the differentiation of MSCs into osteoblasts in an osteogenic condition. These results indicate that PCL-HAp biomaterials combined with MSCs could be a beneficial candidate for subchondral bone regeneration
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