Refine
Year of publication
- 2020 (10) (remove)
Document Type
- Article (10)
Language
- English (10)
Has Fulltext
- yes (10)
Is part of the Bibliography
- no (10)
Keywords
- - (10)
- MRSA (3)
- ESBL (2)
- antimicrobial resistance (2)
- susceptibility testing (2)
- <i>Candida lusitaniae</i> (1)
- <i>Staphylococcus lugdunensis</i> (1)
- <i>Streptococcus pneumoniae</i> (1)
- Actinobacteria (1)
- Enterobacterales (1)
- Euregio (1)
- Firmicutes (1)
- G-quadruplexes (1)
- LL-37 (1)
- LPXTG (1)
- MALDI-TOF (1)
- MALDI-TOF MS (1)
- MDRO (1)
- MHC class I (1)
- MRSA - Methicillin-resistant (1)
- Macrococcus (1)
- Proteobacteria (1)
- Staphylococcus (1)
- adaptation (1)
- antibiotic use (1)
- antigen presentation (1)
- antimicrobial peptides (1)
- antimicrobial susceptibility testing (1)
- blood culture (1)
- breakthrough (1)
- c-myc (1)
- calorimetry (1)
- candidemia (1)
- carbapenamase (1)
- direct-on-target microdroplet growth assay (1)
- fusidic acid (1)
- hBD3 (1)
- infection (1)
- infection prevention (1)
- linear gradient (1)
- mass spectometry (1)
- methicillin-resistant <i>Staphylococcus aureus</i> (1)
- microbiota (1)
- pig (1)
- platelet activation (1)
- proteasome endopeptidase complex (1)
- proteomics (1)
- rapid testing (1)
- resistance (1)
- resistance detection (1)
- sodium bituminosulfonate (1)
- sortase A (1)
- staphylococci (1)
- sub-inhibitory concentrations (1)
- surface proteins (1)
- thermodynamics (1)
- transplantation (1)
- ubiquitin (1)
Institute
- Friedrich-Loeffler-Institut für Medizinische Mikrobiologie (10) (remove)
Publisher
- MDPI (6)
- Frontiers Media S.A. (2)
- Wiley (1)
Abstract
Multiple G‐tracts within the promoter region of the c‐myc oncogene may fold into various G‐quadruplexes with the recruitment of different tracts and guanosine residues for the G‐core assembly. Thermodynamic profiles for the folding of wild‐type and representative truncated as well as mutated sequences were extracted by comprehensive DSC experiments. The unique G‐quadruplex involving consecutive G‐tracts II–V with formation of two one‐nucleotide and one central two‐nucleotide propeller loop, previously proposed to be the biologically most relevant species, was found to be the most stable fold in terms of its Gibbs free energy of formation at ambient temperatures. Its stability derives from its short propeller loops but also from the favorable type of loop residues. Whereas quadruplex folds with long propeller loops are significantly disfavored, a snap‐back loop structure formed by incorporating a 3’‐terminal guanosine into the empty position of a tetrad seems highly competitive based on its thermodynamic stability. However, its destabilization by extending the 3’‐terminus questions the significance of such a species under in vivo conditions.
Investigation of In-Vitro Adaptation toward Sodium Bituminosulfonate in Staphylococcus aureus
(2020)
Abstract
Platelets are small anucleate blood cells with a life span of 7 to 10 days. They are main regulators of hemostasis. Balanced platelet activity is crucial to prevent bleeding or occlusive thrombus formation. Growing evidence supports that platelets also participate in immune reactions, and interaction between platelets and leukocytes contributes to both thrombosis and inflammation. The ubiquitin‐proteasome system (UPS) plays a key role in maintaining cellular protein homeostasis by its ability to degrade non‐functional self‐, foreign, or short‐lived regulatory proteins. Platelets express standard and immunoproteasomes. Inhibition of the proteasome impairs platelet production and platelet function. Platelets also express major histocompatibility complex (MHC) class I molecules. Peptide fragments released by proteasomes can bind to MHC class I, which makes it also likely that platelets can activate epitope specific cytotoxic T lymphocytes (CTLs). In this review, we focus on current knowledge on the significance of the proteasome for the functions of platelets as critical regulators of hemostasis as well as modulators of the immune response.
Matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF MS)-based direct-on-target microdroplet growth assay (DOT-MGA) was recently described as a novel method of phenotypic antimicrobial susceptibility testing (AST). Here, we developed the application of MALDI-TOF MS-based DOT-MGA for Gram-positive bacteria including AST from agar cultures and directly from positive blood cultures (BCs) using the detection of methicillin resistance as example. Consecutively collected, a total of 14 methicillin-resistant Staphylococcus aureus (MRSA) and 14 methicillin-susceptible S. aureus (MSSA) clinical isolates were included. Furthermore, a collection of MRSA challenge strains comprising different SCCmec types, mec genes, and spa types was tested. Blood samples were spiked with MRSA and MSSA and positive BC broth processed by three different methods: serial dilution of BC broth, lysis/centrifugation, and differential centrifugation. Processed BC broth was directly used for rapid AST using DOT-MGA. Droplets of 6 μl with and without cefoxitin at the EUCAST breakpoint concentration were spotted in triplicates onto the surface of a MALDI target. Targets were incubated in a humidity chamber, followed by medium removal and on-target protein extraction with formic acid before adding matrix with an internal standard as a quality control (QC). Spectra were acquired and evaluated using MALDI Biotyper software. First, tests were considered as valid, if the growth control achieved an identification score of ≥1.7. For valid tests, same score criterion was used for resistant isolates when incubated with cefoxitin. An identification score <1.7 after incubation with cefoxitin defined susceptible isolates. On-target protein extraction using formic acid considerably improved detection of methicillin resistance in S. aureus and DOT-MGA showed feasible results for AST from agar cultures after 4 h incubation time. Comparing the different processing methods of positive BC broth, lysis/centrifugation method with a final dilution step 10–1 of the 0.5 McFarland suspension resulted in best test performance after 4 h incubation time. Overall, 96.4% test validity, 100% sensitivity, and 100% specificity were achieved for detection of methicillin resistance in clinical isolates. All strains of the MRSA challenge collection were successfully tested as methicillin-resistant. This first study on Gram-positive organisms showed feasibility and accuracy of MALDI-TOF MS-based DOT-MGA for rapid AST of S. aureus from agar cultures and directly from positive BCs.