2,981 research outputs found

    Inorganic nitrogen availability alters Eucalyptus grandis receptivity to the ectomycorrhizal fungus Pisolithus albus but not symbiotic nitrogen transfer.

    Get PDF
    Forest trees are able to thrive in nutrient-poor soils in part because they obtain growth-limiting nutrients, especially nitrogen (N), through mutualistic symbiosis with ectomycorrhizal (ECM) fungi. Addition of inorganic N into these soils is known to disrupt this mutualism and reduce the diversity of ECM fungi. Despite its ecological impact, the mechanisms governing the observed effects of elevated inorganic N on mycorrhizal communities remain unknown. We address this by using a compartmentalized in vitro system to independently alter nutrients to each symbiont. Using stable isotopes, we traced the nutrient flux under different nutrient regimes between Eucalyptus grandis and its ectomycorrhizal symbiont, Pisolithus albus. We demonstrate that giving E. grandis independent access to N causes a significant reduction in root colonization by P. albus. Transcriptional analysis suggests that the observed reduction in colonization may be caused, in part, by altered transcription of microbe perception genes and defence genes. We show that delivery of N to host leaves is not increased by host nutrient deficiency but by fungal nutrient availability instead. Overall, this advances our understanding of the effects of N fertilization on ECM fungi and the factors governing nutrient transfer in the E. grandis-P. microcarpus interaction

    Low-Grade Versus Medium-Grade Nuclear Sclerotic Cataract Density Produces Identical Surgical and Visual Outcomes: A Prospective Single-Surgeon Study

    Full text link
    Purpose To determine whether the incidence of major complications and postoperative corrected distance visual acuity are comparable for surgery on low-grade versus medium-grade nuclear sclerotic cataracts. Design This was a prospective, consecutive, single-surgeon, no-exclusion study of 1025 cataract cases with one-month follow-up. Methods Patients were divided into two cohorts according to the nuclear sclerosis grade at presentation, as classified using the Lens Opacities Classification System (LOCS) III. Cohort A, representing low-grade nuclear sclerotic cataracts (grades 1-2), consisted of 739 eyes, while Cohort B, representing medium-grade nuclear sclerotic cataracts (grades 3-6), consisted of 286 eyes. Results There was no significant difference in major intraoperative or postoperative complications (p>0.999) between Cohorts A and B. The mean logMar preoperative corrected distance visual acuity (CDVA) in Cohort A was 0.245 as compared with 0.346 in Cohort B (p<0.001). There was no significant difference between cohorts for postoperative CDVA at one day (-0.168 versus -0.118; p=0.070), one week (-0.180 versus -0.147; p=0.405), or one month (-0.185 versus -0.161; p=0.569). Conclusions There was no significant difference in the incidence of operative complications or postoperative CDVA between the cohorts. These findings suggest that, in experienced hands, surgery for medium-grade nuclear sclerotic cataracts is equally effective and safe as compared with that for low-grade nuclear sclerotic cataracts

    (-)-Epigallocatechin-3-gallate (EGCG) maintains k-casein in its pre-fibrillar state without redirecting its aggregation pathway

    Get PDF
    The polyphenol (-)-epigallocatechin-3-gallate (EGCG) has recently attracted much research interest in the field of protein-misfolding diseases because of its potent anti-amyloid activity against amyloid-beta, alpha-synuclein and huntingtin, the amyloid-fibril-forming proteins involved in Alzheimer\u27s, Parkinson\u27s and Huntington\u27s diseases, respectively. EGCG redirects the aggregation of these polypeptides to a disordered off-folding pathway that results in the formation of non-toxic amorphous aggregates. whether this anti-fibril activity is specific to these disease-related target proteins or ismore generic remains to be established. In addition, the mechanism by which EGCG exerts its effects, as with all anti-amyloidogenic polyphenols, remains unclear. To address these aspects, we have investigated the ability of EGCG to inhibit amyloidogenesis of the generic model fibril-forming protein RCMkappa-CN (reduced and carboxymethylated kappa-casein) and thereby protect pheochromocytoma-12 cells from RCMkappa-CN amyloid-induced toxicity. We found that EGCG potently inhibits in vitro fibril formation byRCMkappa-CN [the IC50 for 50 uM RCMkappa-CN is 1 uM]. Biophysical studies reveal that EGCG prevents RCMkappa-CN fibril formation by stabilising RCMkappa-CN in its nativelike state rather than by redirecting its aggregation to the disordered, amorphous aggregation pathway. Thus, while it appears that EGCG is a generic inhibitor of amyloid-fibril formation, the mechanism by which it achieves this inhibition is specific to the target fibril-forming polypeptide. It is proposed that EGCG is directed to the amyloidogenic sheet-turn-sheet motif of monomeric RCMkappa-CN with high affinity by strong non-specific hydrophobic associations. Additional non-covalent pi-pi stacking interactions between the polyphenolic and aromatic residues common to the amyloidogenic sequence are also implicated

    (-)-Epigallocatechin-3-gallate (EGCG) maintains k-casein in its pre-fibrillar state without redirecting its aggregation pathway

    Get PDF
    The polyphenol (-)-epigallocatechin-3-gallate (EGCG) has recently attracted much research interest in the field of protein-misfolding diseases because of its potent anti-amyloid activity against amyloid-beta, alpha-synuclein and huntingtin, the amyloid-fibril-forming proteins involved in Alzheimer\u27s, Parkinson\u27s and Huntington\u27s diseases, respectively. EGCG redirects the aggregation of these polypeptides to a disordered off-folding pathway that results in the formation of non-toxic amorphous aggregates. whether this anti-fibril activity is specific to these disease-related target proteins or ismore generic remains to be established. In addition, the mechanism by which EGCG exerts its effects, as with all anti-amyloidogenic polyphenols, remains unclear. To address these aspects, we have investigated the ability of EGCG to inhibit amyloidogenesis of the generic model fibril-forming protein RCMkappa-CN (reduced and carboxymethylated kappa-casein) and thereby protect pheochromocytoma-12 cells from RCMkappa-CN amyloid-induced toxicity. We found that EGCG potently inhibits in vitro fibril formation byRCMkappa-CN [the IC50 for 50 uM RCMkappa-CN is 1 uM]. Biophysical studies reveal that EGCG prevents RCMkappa-CN fibril formation by stabilising RCMkappa-CN in its nativelike state rather than by redirecting its aggregation to the disordered, amorphous aggregation pathway. Thus, while it appears that EGCG is a generic inhibitor of amyloid-fibril formation, the mechanism by which it achieves this inhibition is specific to the target fibril-forming polypeptide. It is proposed that EGCG is directed to the amyloidogenic sheet-turn-sheet motif of monomeric RCMkappa-CN with high affinity by strong non-specific hydrophobic associations. Additional non-covalent pi-pi stacking interactions between the polyphenolic and aromatic residues common to the amyloidogenic sequence are also implicated

    Curettage for Copious Conjunctival Concretions

    Full text link
    Management of multiple exposed eyelid concretions can be performed successfully in an anesthetized eyelid with gentle curettage of the concretions using a small chalazion curette. It has the advantage of managing the patient supine, providing better eyelid stability and visibility, and minimizing risk in the event of patient movement. This curettage technique was used to facilitate the successful resolution of a patient's ocular surface irritative symptomatology due to multiple exposed concretions

    Light-induced Amaurosis: A Rare Manifestation of Internal Carotid Artery Stenosis

    Full text link
    Light-induced amaurosis (LIA) is a rare presentation of internal carotid artery (ICA) stenosis. This report documents a 74-year-old Caucasian male who presented with profound right monocular vision loss, occurring on every occasion upon entering brightly lit environments. This was managed successfully with a right carotid endarterectomy. This case is presented to highlight the recognition and understanding of LIA and its importance for preservation of vision and prevention of ICA-related stroke

    Apparent Defective Abduction Without Diplopia

    Full text link
    Sixth nerve palsies present with horizontal diplopia and typically have a neurological or neurovascular aetiology. They can be confirmed by clinically evaluating the velocity of the abducting saccade, which is slowed. Three cases are presented in which the patients had apparent defective abduction of one eye, resulting from not only neurological causes but also orbital causes. Clinicians should have a high index of suspicion in patients with defective abduction without diplopia and should include apparent defective abduction without diplopia (ADAD) in the list of potential differential diagnoses, considering not only neurological involvement but also orbital involvement

    Assessment of Obstructive Sleep Apnoea and Sleeping Laterality by Evaluating Upper Eyelid Distraction: A Prospective, Comparative Polysomnographic Study

    Full text link
    Objective Our goal was to evaluate upper eyelid laxity by digital distraction, with the aim to determine sleeping laterality and the likelihood of obstructive sleep apnoea (OSA), and correlate these findings with polysomnography (PSG). Design We conducted a prospective, single-centre multidisciplinary study in a large sleep and respiratory department and an ophthalmology department within a tertiary referral university teaching hospital. Methods Patients with known OSA were evaluated using techniques based on the Lateralising Eyelid Sleep Compression (LESC) study. Upper eyelid laxity was assessed by two masked investigators, and the eyelid side with greater laxity was regarded as indicative of that patient's sleeping laterality: 'investigator-detected sleeping laterality' (ID SL). Each patient was then asked about the laterality of his or her accustomed sleeping position: 'patient-reported sleeping laterality' (PR SL). PSG was conducted according to the standard protocol of the Department of Sleep and Respiratory Medicine (DSRM). 'Polysomnography-detected sleeping laterality' (PSG SL) permitted the extraction of sleep positional data by two masked sleep scientists. Results The reliability of the LESC technique for diagnosing ID SL was demonstrated to be statistically significant (p<0.01). Upper eyelid laxity was significantly greater on the patients' sleeping side (t=6.340, df=45, p<0.01, two-tailed). There was a significant correlation between PR SL and ID SL (rs =0.33). However, PSG SL did not correlate with sleeping laterality compared with both ID SL and PR SL. Conclusion This study confirms that there is a statistically significant correlation of sleeping laterality with increasing upper eyelid laxity in OSA. Counterintuitively, PSG SL correlated poorly with ID SL and PR SL. This may likely be explained by the technical limitations implicit in current PSG techniques

    Peer-to-peer, community self-consumption, and transactive energy: A systematic literature review of local energy market models

    Get PDF
    Peer-to-peer, community or collective self-consumption, and transactive energy markets offer new models for trading energy locally. Over the past five years, there has been significant growth in the amount of academic literature examining how these local energy markets might function. This systematic literature review of 139 peer-reviewed journal articles examines the market designs used in these energy trading models. A modified version of the Business Ecosystem Architecture Modelling framework is used to extract market model information from the literature, and to identify differences and similarities between the models. This paper examines how peer-to-peer, community self-consumption and transactive energy markets are described in current literature. It explores the similarities and differences between these markets in terms of participation, governance structure, topology, and design. This paper systematises peer-to-peer, community self-consumption and transactive energy market designs, identifying six archetypes. Finally, it identifies five evidence gaps which require future research before these markets could be widely adopted. These evidence gaps are the lack of: consideration of physical constraints; a holistic approach to market design and operation; consideration about how these market designs will scale; consideration of information security; and, consideration of market participant privacy
    corecore