University of Basel

About: University of Basel is a education organization based out in Basel, Basel-Stadt, Switzerland. It is known for research contribution in the topics: Population & Gene. The organization has 25084 authors who have published 52975 publications receiving 2388002 citations. The organization is also known as: Universität Basel & Basel University.

RNA Replication of Mouse Hepatitis Virus Takes Place at Double-Membrane Vesicles

Abstract: The replication complexes (RCs) of positive-stranded RNA viruses are intimately associated with cellular membranes. To investigate membrane alterations and to characterize the RC of mouse hepatitis virus (MHV), we performed biochemical and ultrastructural studies using MHV-infected cells. Biochemical fractionation showed that all 10 of the MHV gene 1 polyprotein products examined pelleted with the membrane fraction, consistent with membrane association of the RC. Furthermore, MHV gene 1 products p290, p210, and p150 and the p150 cleavage product membrane protein 1 (MP1, also called p44) were resistant to extraction with Triton X-114, indicating that they are integral membrane proteins. The ultrastructural analysis revealed double-membrane vesicles (DMVs) in the cytoplasm of MHV-infected cells. The DMVs were found either as separate entities or as small clusters of vesicles. To determine whether MHV proteins and viral RNA were associated with the DMVs, we performed immunocytochemistry electron microscopy (IEM). We found that the DMVs were labeled using an antiserum directed against proteins derived from open reading frame 1a of MHV. By electron microscopy in situ hybridization (ISH) using MHV-specific RNA probes, DMVs were highly labeled for both gene 1 and gene 7 sequences. By combined ISH and IEM, positive-stranded RNA and viral proteins localized to the same DMVs. Finally, viral RNA synthesis was detected by labeling with 5-bromouridine 5′-triphosphate. Newly synthesized viral RNA was found to be associated with the DMVs. We conclude from these data that the DMVs carry the MHV RNA replication complex and are the site of MHV RNA synthesis.

A Synthetic Optogenetic Transcription Device Enhances Blood-Glucose Homeostasis in Mice

Abstract: Synthetic biology has advanced the design of genetic devices that can be used to reprogram metabolic activities in mammalian cells. By functionally linking the signal transduction of melanopsin to the control circuit of the nuclear factor of activated T cells, we have designed a synthetic signaling cascade enabling light-inducible transgene expression in different cell lines grown in culture or bioreactors or implanted into mice. In animals harboring intraperitoneal hollow-fiber or subcutaneous implants containing light-inducible transgenic cells, the serum levels of the human glycoprotein secreted alkaline phosphatase could be remote-controlled with fiber optics or transdermally regulated through direct illumination. Light-controlled expression of the glucagon-like peptide 1 was able to attenuate glycemic excursions in type II diabetic mice. Synthetic light-pulse-transcription converters may have applications in therapeutics and protein expression technology.

Direct Visualization of the Outer Membrane of Mycobacteria and Corynebacteria in Their Native State

Abstract: The cell envelope of mycobacteria, which include the causative agents of tuberculosis and leprosy, is crucial for their success as pathogens. Despite a continued strong emphasis on identifying the multiple chemical components of this envelope, it has proven difficult to combine its components into a comprehensive structural model, primarily because the available ultrastructural data rely on conventional electron microscopy embedding and sectioning, which are known to induce artifacts. The existence of an outer membrane bilayer has long been postulated but has never been directly observed by electron microscopy of ultrathin sections. Here we have used cryo-electron microscopy of vitreous sections (CEMOVIS) to perform a detailed ultrastructural analysis of three species belonging to the Corynebacterineae suborder, namely, Mycobacterium bovis BCG, Mycobacterium smegmatis, and Corynebacterium glutamicum, in their native state. We provide new information that accurately describes the different layers of the mycobacterial cell envelope and challenges current models of the organization of its components. We show a direct visualization of an outer membrane, analogous to that found in gram-negative bacteria, in the three bacterial species examined. Furthermore, we demonstrate that mycolic acids, the hallmark of mycobacteria and related genera, are essential for the formation of this outer membrane. In addition, a granular layer and a low-density zone typifying the periplasmic space of gram-positive bacteria are apparent in CEMOVIS images of mycobacteria and corynebacteria. Based on our observations, a model of the organization of the lipids in the outer membrane is proposed. The architecture we describe should serve as a reference for future studies to relate the structure of the mycobacterial cell envelope to its function.

Giantin, a novel conserved Golgi membrane protein containing a cytoplasmic domain of at least 350 kDa.

Abstract: The Golgi complex consists of a series of stacked cisternae in most eukaryotes. Morphological studies indicate the existence of intercisternal cross-bridge structures that may mediate stacking, but their identity is unknown. We have identified a 400-kDa protein, giantin, that is localized to the Golgi complex because its staining in double immunofluorescence experiments was coincident with that of galactosyltransferase, both in untreated cells and in cells treated with agents that disrupt Golgi structure. A monoclonal antibody against giantin yielded Golgi staining in one avian and all mammalian cell types tested, indicating that giantin is a conserved protein. Giantin exhibited reduced mobility on nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was recovered in membrane fractions after differential centrifugation or sucrose flotation, and was not released from membranes by carbonate extraction. Thus, giantin appears to be an integral component of the Golgi membrane with a disulfide-linked lumenal domain. Strikingly, the majority of the polypeptide chain is cytoplasmically disposed, because large (up to 350 kDa) proteolytic fragments of giantin could be released from intact Golgi vesicles. This feature, a large contiguous cytoplasmic domain, is present in the calcium-release channel of muscle that cross-bridges the sarcoplasmic reticulum and transverse tubule membranes. Therefore, giantin's localization, conservation, and physical properties suggest that it may participate in forming the intercisternal cross-bridges of the Golgi complex.

Prognostic Role of Neutrophil-To-Lymphocyte Ratio in Breast Cancer: A Systematic Review and Meta-Analysis

Abstract: The presence of a high neutrophil-to-lymphocyte ratio (NLR) has been associated with increased mortality in several malignancies. Here, we quantify the effect of NLR on survival in patients with breast cancer, and examine the effect of clinicopathologic factors on its prognostic value. A systematic search of electronic databases was conducted to identify publications exploring the association of blood NLR (measured pre treatment) and overall survival (OS) and disease-free survival (DFS) among patients with breast cancer. Data from studies reporting a hazard ratio (HR) and 95% confidence interval (CI) or a P value were pooled in a meta-analysis. Pooled HRs were computed and weighted using generic inverse variance. Meta-regression was performed to evaluate the influence of clinicopathologic factors such as age, disease stage, tumor grade, nodal involvement, receptor status, and NLR cutoff on the HR for OS and DFS. All statistical tests were two-sided. Fifteen studies comprising a total of 8563 patients were included. The studies used different cutoff values to classify high NLR (range 1.9–5.0). The median cutoff value for high NLR used in these studies was 3.0 amongst 13 studies reporting a HR for OS, and 2.5 in 10 studies reporting DFS outcomes. NLR greater than the cutoff value was associated with worse OS (HR 2.56, 95% CI = 1.96–3.35; P < 0.001) and DFS (HR 1.74, 95% CI = 1.47–2.07; P < 0.001). This association was similar in studies including only early-stage disease and those comprising patients with both early-stage and metastatic disease. Estrogen receptor (ER) and HER-2 appeared to modify the effect of NLR on DFS, because NLR had greater prognostic value for DFS in ER-negative and HER2-negative breast cancer. No subgroup showed an influence on the association between NLR and OS. High NLR is associated with an adverse OS and DFS in patients with breast cancer with a greater effect on disease-specific outcome in ER and HER2-negative disease. NLR is an easily accessible prognostic marker, and its addition to established risk prediction models warrants further investigation.