Cytopathicity of Chlamydia is largely reproduced by expression of a single chlamydial protease

Chlamydiae replicate in a vacuole within epithelial cells and commonly induce cell damage and a deleterious inflammatory response of unknown molecular pathogenesis. The chlamydial protease-like activity factor (CPAF) translocates from the vacuole to the cytosol, where it cleaves several cellular proteins. CPAF is synthesized as an inactive precursor that is processed and activated during infection. Here, we show that CPAF can be activated in uninfected cells by experimentally induced oligomerization, reminiscent of the activation mode of initiator caspases. CPAF activity induces proteolysis of cellular substrates including two novel targets, cyclin B1 and PARP, and indirectly results in the processing of pro-apoptotic BH3-only proteins. CPAF activation induces striking morphological changes in the cell and, later, cell death. Biochemical and ultrastructural analysis of the cell death pathway identify the mechanism of cell death as nonapoptotic. Active CPAF in uninfected human cells thus mimics many features of chlamydial infection, implicating CPAF as a major factor of chlamydial pathogenicity, Chlamydia-associated cell damage, and inflammation

Iohexol-based measurement of intestinal permeability in birds

Background: Iohexol has been successfully used as a marker to assess intestinal permeability in humans and various other mammals. The objective of this study was to evaluate the use of oral iohexol as an intestinal permeability marker in four anatomically and nutritionally diverse bird species. Methods: Three dosages (1 ml/kg, 2 ml/kg, 4 ml/kg) of iohexol (755 mg/ml) were administered orally to each six clinically healthy pigeons and chickens at two-week intervals. Iohexol plasma concentration was determined 45, 90 and 180 minutes after administration. A comparative study was performed by administering iohexol twice to each six clinically healthy cockatiels and falcons, and determining iohexol plasma concentration at 45 or 90 minutes after administration. Results: The recommended iohexol dosage for permeability testing in birds was determined to be 1 ml/kg. Median plasma iohexol concentrations were 27.77 mu g/ml in pigeons, 12.97 mu g/ml in chickens, 14.24 mu g/ml in cockatiels, and 47.81 mu g/ml in falcons, 45 minutes after this dosage was administered. At 90 minutes after administration, median plasma iohexol concentrations were 40.68 mu g/ml in pigeons, 21.59 mu g/ml in chickens, 32.03 mu g/ml in cockatiels, and 55.96 mu g/ml in falcons. Conclusions and clinical relevance: Oral iohexol was a safe and feasible marker for intestinal permeability assessment in birds. Further investigations are warranted to establish species-specific reference intervals in larger numbers of healthy birds, and to examine the use of iohexol as a permeability marker in birds with disorders associated with altered intestinal permeability.Peer reviewe

Flotillin-dependent membrane microdomains are required for functional phagolysosomes against fungal infections

© 2020 The Author(s). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Lipid rafts form signaling platforms on biological membranes with incompletely characterized role in immune response to infection. Here we report that lipid-raft microdomains are essential components of phagolysosomal membranes of macrophages and depend on flotillins. Genetic deletion of flotillins demonstrates that the assembly of both major defense complexes vATPase and NADPH oxidase requires membrane microdomains. Furthermore, we describe a virulence mechanism leading to dysregulation of membrane microdomains by melanized wild-type conidia of the important human-pathogenic fungus Aspergillus fumigatus resulting in reduced phagolysosomal acidification. We show that phagolysosomes with ingested melanized conidia contain a reduced amount of free Ca2+ ions and that inhibition of Ca2+-dependent calmodulin activity led to reduced lipid-raft formation. We identify a single-nucleotide polymorphism in the human FLOT1 gene resulting in heightened susceptibility for invasive aspergillosis in hematopoietic stem cell transplant recipients. Collectively, flotillin-dependent microdomains on the phagolysosomal membrane play an essential role in protective antifungal immunity.This work was supported by the International Leibniz Research School ( ILRS ) as part of the excellence graduate school Jena School for Microbial Communication (JSMC) funded by the Deutsche Forschungsgemeinschaft ( DFG ), the Leibniz Science Campus “InfectoOptics,” and the DFG -funded CRC 127 8 “PolyTarget” (project B02 to A.A.B. and Z01 to M.T.F.). C.C. and A.C were supported by the Northern Portugal Regional Operational Programme (NORTE 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund ( FEDER ) ( NORTE-01-0145-FEDER-000013 ), and by the Fundação para a Ciência e Tecnologia ( FCT ) ( SFRH/BPD/96176/2013 to C.C. and IF/00735/2014 to A.C.).info:eu-repo/semantics/publishedVersio

Ba3Ga3N5 - A Novel Host Lattice for Eu2+ - Doped Luminescent Materials with Unexpected Nitridogallate Substructure

The alkaline earth nitridogallate Ba3Ga3N5 was synthesized from the elements in a sodium flux at 760°C utilizing weld shut tantalum ampules. The crystal structure was solved and refined on the basis of single-crystal X-ray diffraction data. Ba3Ga3N5 (space group C2/c (No. 15), a = 16.801(3), b = 8.3301(2), c = 11.623(2) Å, β = 109.92 (3)°, Z = 8) contains a hitherto unknown structural motif in nitridogallates, namely, infinite strands made up of GaN4 tetrahedra, each sharing two edges and at least one corner with neighboring GaN4 units. There are three Ba2+ sites with coordination numbers six or eight, respectively, and one Ba2+ position exhibiting a low coordination number 4 corresponding to a distorted tetrahedron. Eu2+ - doped samples show red luminescence when excited by UV irradiation at room temperature. Luminescence investigations revealed a maximum emission intensity at 638 nm (FWHM =2123 cm−1). Ba3Ga3N5 is the first nitridogallate for which parity allowed broadband emission due to Eu2+ - doping has been found. The electronic structure of both Ba3Ga3N5 as well as isoelectronic but not isostructural Sr3Ga3N5 was investigated by DFT methods. The calculations revealed a band gap of 1.53 eV for Sr3Ga3N5 and 1.46 eV for Ba3Ga3N5

Ablation of C-type natriuretic peptide/cGMP signaling in fibroblasts exacerbates adverse cardiac remodeling in mice

Excessive activation of cardiac fibroblasts (CFs) in response to injury provokes cardiac fibrosis, stiffness, and failure. The local mediators counter-regulating this response remain unclear. Exogenous C-type natriuretic peptide (CNP) exerted antifibrotic effects in preclinical models. To unravel the role of the endogenous hormone, we generated mice with fibroblast-restricted deletion (KO) of guanylyl cyclase-B (GC-B), the cGMP-synthesizing CNP receptor.CNP activated GC-B/cGMP signaling in human and murine CFs, preventing proliferative and promigratory effects of AngiotensinII (AngII) and TGF-β. Fibroblast-specific GC-B-KO mice showed enhanced fibrosis in response to AngII infusions. Moreover, after two weeks of mild pressure-overload induced by transverse aortic constriction (TAC), such KO mice had augmented cardiac fibrosis and hypertrophy, together with systolic and diastolic contractile dysfunction. This was associated with increased expression of the profibrotic genes collagen I, III and periostin. Notably, such responses to AngII and TAC were greater in female as compared to male KO mice. Enhanced AngII-induced CNP expression in female hearts and augmented GC-B expression and activity in female CFs may contribute to this sex disparity.The results show that paracrine CNP signaling in CFs has antifibrotic and antihypertrophic effects. The CNP/GC-B/cGMP pathway might be a target for therapies combating pathological cardiac remodeling

Human small intestinal infection by SARS-CoV-2 is characterized by a mucosal infiltration with activated CD8+ T cells

The SARS-CoV-2 pandemic has so far claimed over three and a half million lives worldwide. Though the SARS-CoV-2 mediated disease COVID-19 has first been characterized by an infection of the upper airways and the lung, recent evidence suggests a complex disease including gastrointestinal symptoms. Even if a direct viral tropism of intestinal cells has recently been demonstrated, it remains unclear, whether gastrointestinal symptoms are caused by direct infection of the gastrointestinal tract by SARS-CoV-2 or whether they are a consequence of a systemic immune activation and subsequent modulation of the mucosal immune system. To better understand the cause of intestinal symptoms we analyzed biopsies of the small intestine from SARS-CoV-2 infected individuals. Applying qRT-PCR and immunohistochemistry, we detected SARS-CoV-2 RNA and nucleocapsid protein in duodenal mucosa. In addition, applying imaging mass cytometry and immunohistochemistry, we identified histomorphological changes of the epithelium, which were characterized by an accumulation of activated intraepithelial CD8(+) T cells as well as epithelial apoptosis and subsequent regenerative proliferation in the small intestine of COVID-19 patients. In summary, our findings indicate that intraepithelial CD8(+) T cells are activated upon infection of intestinal epithelial cells with SARS-CoV-2, providing one possible explanation for gastrointestinal symptoms associated with COVID-19

Ecosystem consequences of invertebrate decline

Human activities cause substantial changes in biodiversity.1,2 Despite ongoing concern about the implications of invertebrate decline,3,4,5,6,7 few empirical studies have examined the ecosystem consequences of invertebrate biomass loss. Here, we test the responses of six ecosystem services informed by 30 above- and belowground ecosystem variables to three levels of aboveground (i.e., vegetation associated) invertebrate community biomass (100%, 36%, and 0% of ambient biomass) in experimental grassland mesocosms in a controlled Ecotron facility. In line with recent reports on invertebrate biomass loss over the last decade, our 36% biomass treatment also represented a decrease in invertebrate abundance (−70%) and richness (−44%). Moreover, we simulated the pronounced change in invertebrate biomass and turnover in community composition across the season. We found that the loss of invertebrate biomass decreases ecosystem multifunctionality, including two critical ecosystem services, aboveground pest control and belowground decomposition, while harvested plant biomass increases, likely because less energy was channeled up the food chain. Moreover, communities and ecosystem functions become decoupled with a lower biomass of invertebrates. Our study shows that invertebrate loss threatens the integrity of grasslands by decoupling ecosystem processes and decreasing ecosystem-service supply

Umsetzung eines digitalen Semesters Augenheilkunde während der COVID-19-Pandemie

Hintergrund Die erste Welle der COVID-19-Pandemie stellte Lehrende und Studierende vor große Herausforderungen, da die studentische Lehre trotz Einschränkung des Präsenzunterrichts stattzufinden hatte. Für Präsenzunterricht und Veranstaltungen mit Patientenkontakt mussten kurzfristig zwischen Mitte März und Beginn des Semesters im April Alternativen gestaltet werden. Ziel der Arbeit Beschreibung von Konzept und Umsetzung der studentischen Lehre an der Augenklinik der Universitätsmedizin Mainz in kompletter digitaler Form im Sommersemester 2020. Konzeptvorstellung Vorlesung, Untersuchungskurs und Praktikum der Augenheilkunde finden an der Universitätsmedizin Mainz im 5. und 6. Semester im Studiengang Humanmedizin statt. Grundlage der Neukonzeption war der bisherige Kursaufbau. Das umgesetzte Konzept umfasste Vorlesungen als Videopodcasts, Untersuchungsvideos, Online-Untersuchungskonferenzen, leitsymptomorientierte interaktive Patientenfälle, Operationsvideos, Anamnesevideos von Patienten und die Gestaltung eines „Live-Patientenzimmers“, in dem Patientenfälle inklusive Live-Übertragung des Spaltlampenbefundes und der Fundoskopie präsentiert wurden. Die Evaluation durch Studierende zeigte eine sehr gute Annahme des Konzeptes. Diskussion Es gelang innerhalb eines Zeitrahmens von 4 Wochen eine vollständige Überarbeitung und Digitalisierung des Kurses Augenheilkunde. Der größte Anteil der Neugestaltung beinhaltete die mediale Produktion von Untersuchungsvideos, interaktiven Patientenfällen und Videopodcasts der Vorlesungen. Diese digitalen Lehrkonzepte können auch in den nächsten Semestern nach Wiederaufnahme des Präsenzunterrichts genutzt werden und die Präsenzlehre in der Augenheilkunde unterstützen.Background The first wave of the COVID-19 pandemic posed great challenges for teachers and students, as teaching had to take place despite the restriction of classroom teaching. For attendance lessons and events with patient contact alternatives had to be arranged at short notice between mid-March and the beginning of the semester in mid-April. Objective Description of the concept and implementation in the student teaching at the Department of Ophthalmology of the University Medical Center Mainz in complete digital form in spring 2020. Presentation of concept Lectures, examination course and practical training in ophthalmology take place in the 5th and 6th semester of the study of human medicine. The basis of the new concept were the former course curricula. Implemented concepts included a complete revision and implementation of lectures as video podcasts, examination videos, online examination conferences, interactive patient cases, narrated videos of surgery, anamnesis videos of patients and the design of the virtual patient room, a live online practice with presentation and examination of patients including transmission of the slit-lamp image to reproduce anterior and posterior segment examination. An evaluation showed a very positive reception of the new concept by students. Discussion Within a tight timeframe of 4 weeks a complete revision of the ophthalmology course was achieved. The implementation was time-consuming, with the largest share in the media production of examination videos, interactive patient cases and video podcasts of the lectures. We consider a reduction of classroom teaching for parts of the learning objectives that can be represented by such videos to be possibly useful. An independent digital appropriation of such content may enable a more productive learning environment in face-to-face teaching

Augmented Reality to Improve Surgical Workflow in Minimally Invasive Transforaminal Lumbar Interbody Fusion – A Feasibility Study With Case Series

Objective Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a highly reproducible procedure for the fusion of spinal segments. We recently introduced the concept of “total navigation” to improve workflow and eliminate fluoroscopy. Image-guided surgery incorporating augmented reality (AR) may further facilitate workflow. In this study, we developed and evaluated a protocol to integrate AR into the workflow of MIS-TLIF. Methods A case series of 10 patients was the basis for the evaluation of a protocol to facilitate tubular MIS-TLIF by the application of AR. Surgical TLIF landmarks were marked on a preoperative computed tomography (CT)-scan using dedicated software. This marked CT scan was fused intraoperatively with the low-dose navigation CT scan using elastic image fusion, and the markers were transferred to the intraoperative scan. Our experience with this workflow and the surgical outcomes were collected. Results Our AR protocol was safely implemented in all cases. The TLIF landmarks could be preoperatively planned and transferred to the intraoperative imaging. Of the 10 cases, 1 case had additionally a synovial cyst resection and in 2 cases an additional bony decompression was performed due to central stenosis. The average procedure time was 160.6±31.9 minutes. The AR implementation added 1.72±0.37 minutes to the overall procedure time. No complications occurred. Conclusion Our findings support the idea that total navigation with AR may further facilitate the workflow, especially in cases with more complex anatomy and for teaching and training purposes. More work is needed to simplify the software and make AR integration more user-friendly