226 research outputs found

    Quantitative insights into the cyanobacterial cell economy

    Full text link
    © Zavřel et al. Phototrophic microorganisms are promising resources for green biotechnology. Compared to heterotrophic microorganisms, however, the cellular economy of phototrophic growth is still insufficiently understood. We provide a quantitative analysis of light-limited, light-saturated, and light-inhibited growth of the cyanobacterium Synechocystis sp. PCC 6803 using a reproducible cultivation setup. We report key physiological parameters, including growth rate, cell size, and photosynthetic activity over a wide range of light intensities. Intracellular proteins were quantified to monitor proteome allocation as a function of growth rate. Among other physiological acclimations, we identify an upregulation of the translational machinery and downregulation of light harvesting components with increasing light intensity and growth rate. The resulting growth laws are discussed in the context of a coarse-grained model of phototrophic growth and available data obtained by a comprehensive literature search. Our insights into quantitative aspects of cyanobacterial acclimations to different growth rates have implications to understand and optimize photosynthetic productivity

    CuCo2_{2}S4_{4} Deposited on TiO2_{2}: Controlling the pH Value Boosts Photocatalytic Hydrogen Evolution

    Get PDF
    Metallic spinel-type CuCo2_{2}S4_{4} nanoparticles were deposited on nanocrystalline TiO2_{2} (P25®), forming heterostructure nanocomposites. The nanocomposites were characterized in detail by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), nitrogen sorption (BET) and UV/Vis spectroscopy. Variation of the CuCo2_{2}S4_{4}:TiO2_{2} ratio to an optimum value generated a catalyst which shows a very high photocatalytic H2_{2} production rate at neutral pH of 32.3 µmol/h (0.72 mLh1^{–1}), which is much larger than for pure TiO2_{2} (traces of H2_{2}). The catalyst exhibits an extraordinary long-term stability and after 70 h irradiation time about 2 mmol H2_{2} were generated. An increased light absorption and an efficient charge separation for the sample with the optimal CuCo2_{2}S4_{4}:TiO2_{2} ratio is most probably responsible for the high catalytic activity

    New genus of the tribe Ceutorhynchini (Coleoptera: Curculionidae) from the late Oligocene of Enspel, southwestern Germany, with a remark on the role of weevils in the ancient food web

    Get PDF
    The new weevil genus Igneonasus gen. nov. (type species: I. rudolphi sp. nov.) of the tribe Ceutorhynchini (Curculionidae: Conoderinae: Ceutorhynchitae) is described from the late Oligocene of Fossillagerstätte Enspel, Germany. The new genus differs from the similar genus Stenocarus Thomson, 1859 in the anterior margin of the pronotum, which is not raised, a pronotum without tubercles on the sides, and a femur without teeth. This weevil is the largest representative of this supertribe and the first fossil Curculionidae species described from the paleolake Enspel. In this ancient ecosystem, weevils were at least sometimes an important food resource for the cyprinid fish Palaeorutilus enspelensis.</p

    Ammonia Decomposition in the Process Chain for a Renewable Hydrogen Supply

    Get PDF
    This review article deals with the challenge to identify catalyst materials from literature studies for the ammonia decomposition reaction with potential for application in large-scale industrial processes. On the one hand, the requirements on the catalyst are quite demanding. Of central importance are the conditions for the primary reaction that have to be met by the catalyst. Likewise, the catalytic performance, i.e., an ideally quantitative conversion, and a high lifetime are critical as well as the consideration of requirements on the product properties in terms of pressure or by-products for potential follow-up processes, in this case synthesis gas applications. On the other hand, the evaluation of the multitude of literature studies poses difficulties due to significant varieties in catalytic testing protocols

    Fungi hijack a ubiquitous plant apoplastic endoglucanase to release a ROS scavenging beta-glucan decasaccharide to subvert immune responses

    Get PDF
    Plant pathogenic and beneficial fungi have evolved several strategies to evade immunity and cope with host-derived hydrolytic enzymes and oxidative stress in the apoplast, the extracellular space of plant tissues. Fungal hyphae are surrounded by an inner insoluble cell wall layer and an outer soluble extracellular polysaccharide (EPS) matrix. Here, we show by proteomics and glycomics that these two layers have distinct protein and carbohydrate signatures, and hence likely have different biological functions. The barley (Hordeum vulgare) β-1,3-endoglucanase HvBGLUII, which belongs to the widely distributed apoplastic glycoside hydrolase 17 family (GH17), releases a conserved β-1,3;1,6-glucan decasaccharide (β-GD) from the EPS matrices of fungi with different lifestyles and taxonomic positions. This low molecular weight β-GD does not activate plant immunity, is resilient to further enzymatic hydrolysis by β-1,3-endoglucanases due to the presence of three β-1,6-linked glucose branches and can scavenge reactive oxygen species. Exogenous application of β-GD leads to enhanced fungal colonization in barley, confirming its role in the fungal counter-defensive strategy to subvert host immunity. Our data highlight the hitherto undescribed capacity of this often-overlooked EPS matrix from plant-associated fungi to act as an outer protective barrier important for fungal accommodation within the hostile environment at the apoplastic plant–microbe interface

    Selenium Utilization by GPX4 Is Required to Prevent Hydroperoxide-Induced Ferroptosis

    Get PDF
    open24siSelenoproteins are rare proteins among all kingdoms of life containing the 21st amino acid, selenocysteine. Selenocysteine resembles cysteine, differing only by the substitution of selenium for sulfur. Yet the actual advantage of selenolate- versus thiolate-based catalysis has remained enigmatic, as most of the known selenoproteins also exist as cysteine-containing homologs. Here, we demonstrate that selenolate-based catalysis of the essential mammalian selenoprotein GPX4 is unexpectedly dispensable for normal embryogenesis. Yet the survival of a specific type of interneurons emerges to exclusively depend on selenocysteine-containing GPX4, thereby preventing fatal epileptic seizures. Mechanistically, selenocysteine utilization by GPX4 confers exquisite resistance to irreversible overoxidation as cells expressing a cysteine variant are highly sensitive toward peroxide-induced ferroptosis. Remarkably, concomitant deletion of all selenoproteins in Gpx4cys/cys cells revealed that selenoproteins are dispensable for cell viability provided partial GPX4 activity is retained. Conclusively, 200 years after its discovery, a specific and indispensable role for selenium is provided.openIngold, Irina; Berndt, Carsten; Schmitt, Sabine; Doll, Sebastian; Poschmann, Gereon; Buday, Katalin; Roveri, Antonella; Peng, Xiaoxiao; Porto Freitas, Florencio; Seibt, Tobias; Mehr, Lisa; Aichler, Michaela; Walch, Axel; Lamp, Daniel; Jastroch, Martin; Miyamoto, Sayuri; Wurst, Wolfgang; Ursini, Fulvio; Arnér, Elias S J; Fradejas-Villar, Noelia; Schweizer, Ulrich; Zischka, Hans; Friedmann Angeli, José Pedro; Conrad, MarcusIngold, Irina; Berndt, Carsten; Schmitt, Sabine; Doll, Sebastian; Poschmann, Gereon; Buday, Katalin; Roveri, Antonella; Peng, Xiaoxiao; Porto Freitas, Florencio; Seibt, Tobias; Mehr, Lisa; Aichler, Michaela; Walch, Axel; Lamp, Daniel; Jastroch, Martin; Miyamoto, Sayuri; Wurst, Wolfgang; Ursini, Fulvio; Arnér, Elias S J; Fradejas-Villar, Noelia; Schweizer, Ulrich; Zischka, Hans; Friedmann Angeli, José Pedro; Conrad, Marcu

    Anthroposophic medical therapy in chronic disease: a four-year prospective cohort study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The short consultation length in primary care is a source of concern, and the wish for more consultation time is a common reason for patients to seek complementary medicine. Physicians practicing anthroposophic medicine have prolonged consultations with their patients, taking an extended history, addressing constitutional, psychosocial, and biographic aspect of patients' illness, and selecting optimal therapy. In Germany, health benefit programs have included the reimbursement of this additional physician time. The purpose of this study was to describe clinical outcomes in patients with chronic diseases treated by anthroposophic physicians after an initial prolonged consultation.</p> <p>Methods</p> <p>In conjunction with a health benefit program in Germany, 233 outpatients aged 1–74 years, treated by 72 anthroposophic physicians after a consultation of at least 30 min participated in a prospective cohort study. Main outcomes were disease severity (Disease and Symptom Scores, physicians' and patients' assessment on numerical rating scales 0–10) and quality of life (adults: SF-36, children aged 8–16: KINDL, children 1–7: KITA). Disease Score was documented after 0, 6 and 12 months, other outcomes after 0, 3, 6, 12, 18, 24, and (Symptom Score and SF-36) 48 months.</p> <p>Results</p> <p>Most common indications were mental disorders (17.6% of patients; primarily depression and fatigue), respiratory diseases (15.5%), and musculoskeletal diseases (11.6%). Median disease duration at baseline was 3.0 years (interquartile range 0.5–9.8 years). The consultation leading to study enrolment lasted 30–60 min in 51.5% (120/233) of patients and > 60 min in 48.5%. During the following year, patients had a median of 3.0 (interquartile range 1.0–7.0) prolonged consultations with their anthroposophic physicians, 86.1% (167/194) of patients used anthroposophic medication.</p> <p>All outcomes except KITA Daily Life subscale and KINDL showed significant improvement between baseline and all subsequent follow-ups. Improvements from baseline to 12 months were: Disease Score from mean (standard deviation) 5.95 (1.74) to 2.31 (2.29) (p < 0.001), Symptom Score from 5.74 (1.81) to 3.04 (2.16) (p < 0.001), SF-36 Physical Component Summary from 44.01 (10.92) to 47.99 (10.43) (p < 0.001), SF-36 Mental Component Summary from 42.34 (11.98) to 46.84 (10.47) (p < 0.001), and KITA Psychosoma subscale from 62.23 (19.76) to 76.44 (13.62) (p = 0.001). All these improvements were maintained until the last follow-up. Improvements were similar in patients not using diagnosis-related adjunctive therapies within the first six study months.</p> <p>Conclusion</p> <p>Patients treated by anthroposophic physicians after an initial prolonged consultation had long-term reduction of chronic disease symptoms and improvement of quality of life. Although the pre-post design of the present study does not allow for conclusions about comparative effectiveness, study findings suggest that physician-provided anthroposophic therapy may play a beneficial role in the long-term care of patients with chronic diseases.</p

    Gene Expression Changes Associated with the Airway Wall Response to Injury

    Get PDF
    Understanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. As only limited data is available in relation to the in vivo characterisation of the molecular features of repair in the airway we sought to characterise the dynamic changes in gene expression that are associated with the early response to physical injury in the airway wall.We profiled gene expression changes in the airway wall using a large animal model of physical injury comprising bronchial brush biopsy in anaesthetised sheep. The experimental design featured sequential studies in the same animals over the course of a week and yielded data relating to the response at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the response included the up-regulation of cell cycle genes at d1 and d3, and the latter pronounced up-regulation of extracellular matrix-related genes at d3 and d7.It is possible to follow the airway wall response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance

    Homeosis in a scorpion supports a telopodal origin of pectines and components of the book lungs

    Get PDF
    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated
    corecore