354 research outputs found

    Mechanosensitive Expression of a Lipoxygenase Gene in Wheat

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    Progress in customer relationship management adoption: a cross-sector study

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    Although customer relationship management (CRM) is widely used by organizations to capture and manage customer data, the process of implementation can be problematic. This article takes a multi-sector view of CRM implementation in three areas of the UK services sector: banking and finance; professional services; and the government/public sector. The study captures variations in CRM practice and implementation across these sectors, applying an existing framework of CRM implementation to tease out progress in relation to people (the company's staff), the company itself, the customers, and the technology. The implications for organizations that have reached different implementation stages in their CRM journey are considered

    Defining the Cellular Environment in the Organ of Corti following Extensive Hair Cell Loss: A Basis for Future Sensory Cell Replacement in the Cochlea

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    Background: Following the loss of hair cells from the mammalian cochlea, the sensory epithelium repairs to close the lesions but no new hair cells arise and hearing impairment ensues. For any cell replacement strategy to be successful, the cellular environment of the injured tissue has to be able to nurture new hair cells. This study defines characteristics of the auditory sensory epithelium after hair cell loss. Methodology/Principal Findings: Studies were conducted in C57BL/6 and CBA/Ca mice. Treatment with an aminoglycoside-diuretic combination produced loss of all outer hair cells within 48 hours in both strains. The subsequent progressive tissue re-organisation was examined using immunohistochemistry and electron microscopy. There was no evidence of significant de-differentiation of the specialised columnar supporting cells. Kir4.1 was down regulated but KCC4, GLAST, microtubule bundles, connexin expression patterns and pathways of intercellular communication were retained. The columnar supporting cells became covered with non-specialised cells migrating from the outermost region of the organ of Corti. Eventually non-specialised, flat cells replaced the columnar epithelium. Flat epithelium developed in distributed patches interrupting regions of columnar epithelium formed of differentiated supporting cells. Formation of the flat epithelium was initiated within a few weeks post-treatment in C57BL/6 mice but not for several months in CBA/Ca’s, suggesting genetic background influences the rate of re-organisation

    Retention of progenitor cell phenotype in otospheres from guinea pig and mouse cochlea

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    Abstract\ud \ud Background\ud Culturing otospheres from dissociated organ of Corti is an appropriate starting point aiming at the development of cell therapy for hair cell loss. Although guinea pigs have been widely used as an excellent experimental model for studying the biology of the inner ear, the mouse cochlea has been more suitable for yielding otospheres in vitro. The aim of this study was to compare conditions and outcomes of otosphere suspension cultures from dissociated organ of Corti of either mouse or guinea pig at postnatal day three (P3), and to evaluate the guinea pig as a potential cochlea donor for preclinical cell therapy.\ud \ud \ud Methods\ud Organs of Corti were surgically isolated from P3 guinea pig or mouse cochlea, dissociated and cultivated under non-adherent conditions. Cultures were maintained in serum-free DMEM:F12 medium, supplemented with epidermal growth factor (EGF) plus either basic fibroblast growth factor (bFGF) or transforming growth factor alpha (TGFα). Immunofluorescence assays were conducted for phenotype characterization.\ud \ud \ud Results\ud The TGFα group presented a number of spheres significantly higher than the bFGF group. Although mouse cultures yielded more cells per sphere than guinea pig cultures, sox2 and nestin distributed similarly in otosphere cells from both organisms. We present evidence that otospheres retain properties of inner ear progenitor cells such as self-renewal, proliferation, and differentiation into hair cells or supporting cells.\ud \ud \ud Conclusions\ud Dissociated guinea pig cochlea produced otospheres in vitro, expressing sox2 and nestin similarly to mouse otospheres. Our data is supporting evidence for the presence of inner ear progenitor cells in the postnatal guinea pig. However, there is limited viability for these cells in neonatal guinea pig cochlea when compared to the differentiation potential observed for the mouse organ of Corti at the same developmental stage

    Evidence for supporting cell mitosis in response to acoustic trauma in the avian inner ear

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    Acoustic overstimulation can lead to sensory cell (hair cell) loss in the auditory epithelium. Damaged hair cells in the organ of Corti (the mammalian auditory end-organ) degenerate and are replaced by non-sensory cells (supporting cells) which construct an irreversible scar. In birds, however, auditory hair cells which are damaged by acoustic trauma or ototoxic drugs may be replaced by new hair cells. As first step in determining the mechanism of hair cell regeneration, we developed an assay for cell divisions in the auditory epithelium after acoustic trauma. The results of these experiments demonstrate that supporting cells in damaged regions of the auditory epithelium incorporate the DNA-specific marker bromodeoxyuridine as early as one day after noise exposure. We provide direct evidence that following acoustic insult to the avian inner ear, supporting cells which reside within the sensory epithelium divide near the luminal surface and repopulate the epithelium. These results suggest that supporting cells participate in scar formation during hair cell degeneration, and produce new cells for regeneration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47429/1/11068_2005_Article_BF01191727.pd

    SAG101 Forms a Ternary Complex with EDS1 and PAD4 and Is Required for Resistance Signaling against Turnip Crinkle Virus

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    EDS1, PAD4, and SAG101 are common regulators of plant immunity against many pathogens. EDS1 interacts with both PAD4 and SAG101 but direct interaction between PAD4 and SAG101 has not been detected, leading to the suggestion that the EDS1-PAD4 and EDS1-SAG101 complexes are distinct. We show that EDS1, PAD4, and SAG101 are present in a single complex in planta. While this complex is preferentially nuclear localized, it can be redirected to the cytoplasm in the presence of an extranuclear form of EDS1. PAD4 and SAG101 can in turn, regulate the subcellular localization of EDS1. We also show that the Arabidopsis genome encodes two functionally redundant isoforms of EDS1, either of which can form ternary complexes with PAD4 and SAG101. Simultaneous mutations in both EDS1 isoforms are essential to abrogate resistance (R) protein-mediated defense against turnip crinkle virus (TCV) as well as avrRps4 expressing Pseudomonas syringae. Interestingly, unlike its function as a PAD4 substitute in bacterial resistance, SAG101 is required for R-mediated resistance to TCV, thus implicating a role for the ternary complex in this defense response. However, only EDS1 is required for HRT-mediated HR to TCV, while only PAD4 is required for SA-dependent induction of HRT. Together, these results suggest that EDS1, PAD4 and SAG101 also perform independent functions in HRT-mediated resistance

    Generating inner ear organoids containing putative cochlear hair cells from human pluripotent stem cells

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    In view of the prevalence of sensorineural hearing defects in an ageing population, the development of protocols to generate cochlear hair cells and their associated sensory neurons as tools to further our understanding of inner ear development are highly desirable. We report herein a robust protocol for the generation of both vestibular and cochlear hair cells from human pluripotent stem cells which represents an advance over currently available methods that have been reported to generate vestibular hair cells only. Generating otic organoids from human pluripotent stem cells using a three-dimensional culture system, we show formation of both types of sensory hair cells bearing stereociliary bundles with active mechano-sensory ion channels. These cells share many morphological characteristics with their in vivo counterparts during embryonic development of the cochlear and vestibular organs and moreover demonstrate electrophysiological activity detected through single-cell patch clamping. Collectively these data represent an advance in our ability to generate cells of an otic lineage and will be useful for building models of the sensory regions of the cochlea and vestibule

    Enhancing methane production from lignocellulosic biomass by combined steam‑explosion pretreatment and bioaugmentation with cellulolytic bacterium Caldicellulosiruptor bescii

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    Background: Biogas production from lignocellulosic biomass is generally considered to be challenging due to the recalcitrant nature of this biomass. In this study, the recalcitrance of birch was reduced by applying steam-explosion (SE) pretreatment (210 °C and 10 min). Moreover, bioaugmentation with the cellulolytic bacterium Caldicellulosiruptor bescii was applied to possibly enhance the methane production from steam-exploded birch in an anaerobic digestion (AD) process under thermophilic conditions (62 °C). Results: Overall, the combined SE and bioaugmentation enhanced the methane yield up to 140% compared to untreated birch, while SE alone contributed to the major share of methane enhancement by 118%. The best methane improvement of 140% on day 50 was observed in bottles fed with pretreated birch and bioaugmentation with lower dosages of C. bescii (2 and 5% of inoculum volume). The maximum methane production rate also increased from 4-mL CH4/ g VS (volatile solids)/day for untreated birch to 9-14-mL CH4/ g VS/day for steam-exploded birch with applied bioaugmentation. Bioaugmentation was particularly effective for increasing the initial methane production rate of the pretreated birch yielding 21-44% more methane than the pretreated birch without applied bioaugmentation. The extent of solubilization of the organic matter was increased by more than twofold when combined SE pretreatment and bioaugmentation was used in comparison with the methane production from untreated birch. The beneficial effects of SE and bioaugmentation on methane yield indicated that biomass recalcitrance and hydrolysis step are the limiting factors for efficient AD of lignocellulosic biomass. Microbial community analysis by 16S rRNA amplicon sequencing showed that the microbial community composition was altered by the pretreatment and bioaugmentation processes. Notably, the enhanced methane production by pretreatment and bioaugmentation was well correlated with the increase in abundance of key bacterial and archaeal communities, particularly the hydrolytic bacterium Caldicoprobacter, several members of syntrophic acetate oxidizing bacteria and the hydrogenotrophic Methanothermobacter. Conclusion: Our findings demonstrate the potential of combined SE and bioaugmentation for enhancing methane production from lignocellulosic biomass

    The effect of nutrients on pyrrolizidine alkaloids in Senecio plants and their interactions with herbivores and pathogens

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    The aim of this review is to combine the knowledge of studies on effects of nutrients on pyrrolizidine alkaloids (PAs) in Senecio with those studies of effects of PAs on herbivores and pathogens in order to predict the effects that nutrients may have on herbivores and pathogens via changes in PAs. We discuss whether these predictions match with the outcome of studies where the effect of nutrients on herbivores and insects were measured. PA concentrations in S. jacobaea, S. vulgaris and S. aquaticus were mostly reduced by NPK fertilization, with genotype-specific effects occurring. Plant organs varied in their response to increased fertilization; PA concentrations in flowers remained constant, while shoot and roots were mostly negatively affected. Biomass change is probably largely responsible for the change in concentrations. Nutrients affect both the variety and the levels of PAs in the plant. The reduced PA concentrations after NPK fertilization was expected to benefit herbivores, but no or negative responses from insect herbivores were observed. Apparently other changes in the plant after fertilization are overriding the effect of PAs. Pathogens do seem to benefit from the lower PA concentrations after fertilization; they were more detrimental to fertilized plants than to unfertilized control plants. Future studies should include the effect of each element of nutrients separately and in combinations in order to gain more insight in the effect of specific nutrients on PA content in Senecio plants
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