Extensive coronavirus-induced membrane rearrangements are not a determinant of pathogenicity

Positive-strand RNA (+RNA) viruses rearrange cellular membranes during replication, possibly in order to concentrate and arrange viral replication machinery for efficient viral RNA synthesis. Our previous work showed that in addition to the conserved coronavirus double membrane vesicles (DMVs), Beau-R, an apathogenic strain of avian Gammacoronavirus infectious bronchitis virus (IBV), induces regions of ER that are zippered together and tethered open-necked double membrane spherules that resemble replication organelles induced by other +RNA viruses. Here we compared structures induced by Beau-R with the pathogenic lab strain M41 to determine whether membrane rearrangements are strain dependent. Interestingly, M41 was found to have a low spherule phenotype. We then compared a panel of pathogenic, mild and attenuated IBV strains in ex vivo tracheal organ culture (TOC). Although the low spherule phenotype of M41 was conserved in TOCs, each of the other tested IBV strains produced DMVs, zippered ER and spherules. Furthermore, there was a significant correlation for the presence of DMVs with spherules, suggesting that these structures are spatially and temporally linked. Our data indicate that virus induced membrane rearrangements are fundamentally linked to the viral replicative machinery. However, coronavirus replicative apparatus clearly has the plasticity to function in different structural contexts

What we know about elemental bulk chondrule and matrix compositions: Presenting the ChondriteDB Database

Chondrules and matrix are the major components of chondritic meteorites and represent a significant evolutionary step in planet formation. The formation and evolution of chondrules and matrix and, in particular, the mechanics of chondrule formation remain the biggest unsolved challenge in meteoritics. A large number of studies of these major components not only helped to understand these in ever greater detail, but also produced a remarkably large body of data. Studying all available data has become known as analyses and promises deep insights - in this case - to chondrule and matrix formation and relationships. Looking at all data may also allow one to better understand the mechanism of chondrule formation or, equally important, what information we might be missing to identify this process. A database of all available chondrule and matrix data further provides an overview and quick visualisation, which will not only help to solve actual problems, but also enable students and future researchers to quickly access and understand all we know about these components. We collected all available data on elemental bulk chondrule and matrix compositions in a database that we call ChondriteDB. The database also contains petrographic and petrologic information on chondrules. Currently, ChondriteDB contains about 2388 chondrule and 1064 matrix data from 70 different publications and 161 different chondrites. Future iterations of ChondriteDB will include isotope data and information on other chondrite components. Data quality is of critical importance. However, as we discuss, quality is not an objective category, but a subjective judgement. Quantifiable data acquisition categories are required that allow selecting the appropriate data from a database in the context of a given research problem. We provide a comprehensive overview on the contents of ChondriteDB. The database is available as an Excel file upon request from the senior author of this paper, or can be accessed through MetBase. (C) 2017 Elsevier GmbH. All rights reserved

A ray of hope for the hopeless: Hemisection of mandibular molar with socket preservation

Introduction: The management, treatment and long-term retention of mandibular molar teeth with furcation involvement have always been a challenge in periodontal therapy. Hemisection has been used successfully to retain teeth with furcation involvement. The term hemisection refers to the sectioning of a molar tooth, with the removal of an unrestorable root which may be affected by periodontal, endodontic, structural (cracked roots), or caries. Case Report : This case report describes a simple procedure of hemisection in a mandibular molar with socket preservation with help of an alloplastic bone graft and subsequent restoration of the tooth with fixed prothesis. Discussion: Hemisection represents a form of conservative procedure, which aims at retaining as much of the original tooth structure as possible. It may be a suitable alternative to extraction. Hemisection of the affected tooth allows the preservation of tooth structure, alveolar bone and cost savings (time and money) over other treatment options. The preservation of posterior abutment teeth permits oral rehabilitation with fixed bridges instead of removable prosthesis. Conclusion: The keys to long term success appear to be thorough diagnosis followed by interdisciplinary approach with endodontic, surgical and prosthetic procedures. Preservation of a hopeless tooth is possible by selecting patients with good oral hygiene, and careful surgical and restorative management

Fe isotope composition of bulk chondrules from Murchison (CM2): Constraints for parent body alteration, nebula processes and chondrule-matrix complementarity

Iron isotope compositions of bulk chondrules are so far only known from few studies on CV and some ordinary chondrites. We studied 38 chondrules from the CM chondrite Murchison. This is in particular challenging, as CM chondrites contain the smallest chondrules (av. diameter: 149 μm) of all chondrite groups, except for CH chondrites. Bulk chondrules have δ56Fe between -0.62 and +0.24‰ relative to the IRMM-014 standard. Bulk Murchison has as all chondrites a δ56Fe of 0.00‰. The δ56Fe distribution of the Murchison chondrule population is continuous and close to normal. The width of the δ56Fe distribution is narrower than that of the Allende chondrule population. Opaque modal abundances in Murchison chondrules is in about 67% of the chondrules close to 0 vol%, and in 33% typically up to 6.5 vol.%. Chondrule element ratios of Al/Mg´and Fe/Mg are sub-chondritic, while bulk Murchison has chondritic ratios. No correlations exist between Ni/Mg and modal abundance of opaque phases,possibly because opaque phases were oxidised during parent Body alteration. Initially maybe larger variations of bulk chondrule Fe isotope compositions may have been reduced during parent body alteration. Variable bulk chondrule Fe isotope compositions were established during evaporation and re-condensation prior to accretion in the Murchison parent body. Variable bulk chondrule Fe isotope compositions and a chondritic bulk Murchison, together with complementary element compositions, while bulk Murchison is chondritic, support the idea that chondrules and matrix formed from a single reservoir and were then accreted in the parent body. The formation in a single region also explains the compositional distribution of the chondrule population in Murchison

Candida albicans induces monocyte training via epigenetic reprogramming through a dectin-1-dependent pathway

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Preload on draft gear in freight trains

Adjusting draft gear preloads requires minimum or no structural changes to the existing coupler systems. Better or optimal preloads are more promising to be implemented than modifying other parameters such as wedge angles and spring stiffness. This paper presents a method to model draft gear preloads and investigates the numerical step-size requirements for the simulations of draft gear preloads. The implications of preloads on the draft gear impact performance, longitudinal train dynamics performance and coupler fatigue damage were also investigated. The results show that step sizes of less than 2.5 and 0.2 ms (with the fourth Runge–Kutta solver) are recommended to simulate preloads during the simulations of longitudinal train dynamics and wagon impacts, respectively. Wagon impact simulations indicate that the increase of draft gear preloads can noticeably decrease the maximum draft gear deflection during wagon impacts. Longitudinal train dynamics simulations for a distributed power train with 214 vehicles on a 320 km long track were conducted. The longitudinal train dynamics simulations indicate that, when the preload is increased from 0 to 100 kN, the difference of maximum vehicle accelerations is insignificant. When the draft gear preload is further increased to 200 or 300 kN, maximum vehicle accelerations are evidently increased. Draft gear preloads do not noticeably influence the maximum tensile coupler forces. However, preloads have evident implications for maximum compressive coupler forces, especially for the second half of the train. Coupler fatigue damage calculations show that the sum of coupler fatigue damage evidently decreases with the increase of draft gear preload. The damage for the zero preload case is 8.7 times than that of the 300 kN preload case. © 2017, IMechE 2017