To evaluate the molecular mechanism of fluoroquinolones resistance in Mycoplasma hominis (MH) clinical strains isolated from urogenital specimens. 15 MH clinical isolates with different phenotypes of resistance to fluoroquinolones antibiotics were screened for mutations in the quinolone resistance-determining regions (QRDRs) of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE) in comparison with the reference strain PG21, which is susceptible to fluoroquinolones antibiotics. 15 MH isolates with three kinds of quinolone resistance phenotypes were obtained. Thirteen out of these quinolone-resistant isolates were found to carry nucleotide substitutions in either gyrA or parC. There were no alterations in gyrB and no mutations were found in the isolates with a phenotype of resistance to Ofloxacin (OFX), intermediate resistant to Levofloxacin (LVX) and Sparfloxacin (SFX), and those susceptible to all three tested antibiotics. The molecular mechanism of fluoroquinolone resistance in clinical isolates of MH was reported in this study. The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is likely associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.
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http://dx.doi.org/10.1590/s1517-83822014000100034 | DOI Listing |
J Chem Inf Model
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Geneis (Beijing) Co. Ltd., Beijing 100102, China.
Identification of potential drug-target interactions (DTIs) is a crucial step in drug discovery and repurposing. Although deep learning effectively deciphers DTIs, most deep learning-based methods represent drug features from only a single perspective. Moreover, the fusion method of drug and protein features needs further refinement.
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Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany.
Interferon alpha (IFNa) is approved for the therapy of patients (pts) with polycythemia vera (PV), a subtype of myeloproliferative neoplasms (MPN). Some pts achieve molecular responses (MR), but clonal factors sensitizing for MR remain elusive. We integrated colony formation and differentiation assays with single-cell RNA seq and genotyping in PV-derived cells vs.
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January 2025
Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States.
Natural enzymes are powerful catalysts, reducing the apparent activation energy for reactions and enabling chemistry to proceed as much as 10 times faster than the corresponding solution reaction. It has been suggested for some time that, in some cases, quantum tunneling can contribute to this rate enhancement by offering pathways through a barrier inaccessible to activated events. A central question of interest to both physical chemists and biochemists is the extent to which evolution introduces mechanisms below the barrier, or tunneling mechanisms.
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January 2025
Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
The small GTPase R-RAS2 regulates homeostatic proliferation and survival of T and B lymphocytes and, when present in high amounts, drives the development of B cell chronic lymphocytic leukemia. In normal and leukemic lymphocytes, R-RAS2 constitutively binds to antigen receptors through their immunoreceptor tyrosine-based activation motifs (ITAMs) and promotes tonic activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway. Here, we examined the molecular mechanisms underlying this direct interaction and its consequences for R-RAS2 activity.
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February 2025
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