Search results for "microbiology"
showing 10 items of 7546 documents
New Synthetic Nitro-Pyrrolomycins as Promising Antibacterial and Anticancer Agents
2020
: Pyrrolomycins (PMs) are polyhalogenated antibiotics known as powerful biologically active compounds, yet featuring high cytotoxicity. The present study reports the antibacterial and antitumoral properties of new chemically synthesized PMs, where the three positions of the pyrrolic nucleus were replaced by nitro groups, aiming to reduce their cytotoxicity while maintaining or even enhancing the biological activity. Indeed, the presence of the nitro substituent in diverse positions of the pyrrole determined an improvement of the minimal bactericidal concentration (MBC) against Gram-positive (i.e., Staphylococcus aureus) or -negative (i.e., Pseudomonas aeruginosa) pathogen strains as compare…
Gut Microbiome Associates With Lipid-Lowering Effect of Rosuvastatin in Vivo
2018
Source at https://doi.org/10.3389/fmicb.2018.00530 . Background: Statin has been widely used to treat hyperlipidemia because of its high potency in decreasing cholesterol levels. The present study aimed to examine the lipid-lowering effect of rosuvastatin and the composition, diversity and species abundance of gut microbiome in association with rosuvastatin efficacy. TRIAL REGISTRATION: ChiCTR-ORC-17013212 at the First Affiliated Hospital of Dalian Medical University, November 2, 2017. Results:Totally 64 patients with hyperlipidemia were treated with 10 mg/day of rosuvastatin for 4-8 weeks. Blood lipid indicators triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL), lo…
Immunodominant Cytomegalovirus Epitopes Suppress Subdominant Epitopes in the Generation of High-Avidity CD8 T Cells
2021
CD8+ T-cell responses to pathogens are directed against infected cells that present pathogen-encoded peptides on MHC class-I molecules. Although natural responses are polyclonal, the spectrum of peptides that qualify for epitopes is remarkably small even for pathogens with high coding capacity. Among those few that are successful at all, a hierarchy exists in the magnitude of the response that they elicit in terms of numbers of CD8+ T cells generated. This led to a classification into immunodominant and non-immunodominant or subordinate epitopes, IDEs and non-IDEs, respectively. IDEs are favored in the design of vaccines and are chosen for CD8+ T-cell immunotherapy. Using murine cytomegalov…
Validation of a plasma metabolomics model that allows anticipation of the occurrence of cytomegalovirus DNAaemia in allogeneic stem cell transplant r…
2018
A plasma metabolomic model obtained by means of untargeted 1H nuclear magnetic resonance, to which taurine, choline, methylamine, total glutathione, trimethylamine N-oxide, lactate, lysine, isoleucine, total fatty acids and unsaturated fatty acids contributed, was validated for the prediction of first episodes of cytomegalovirus (CMV) DNAaemia in a cohort of 79 allogeneic stem haematopoietic stem cell transplant (allo-HSCT) recipients. The predictive success rate was nearly 65 % for patients at both low and high risk of CMV-related complications according to their baseline characteristics. Plasma metabolomics profiling shortly after engraftment (day 21 after transplantation) allowed the ant…
Performance of disc diffusion, MIC gradient tests and Vitek 2 for ceftolozane/tazobactam and ceftazidime/avibactam susceptibility testing of Pseudomo…
2021
AbstractObjectivesTo assess performance of disc diffusion, gradient tests and Vitek 2 system to determine the susceptibility of clinical Pseudomonas aeruginosa strains to ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA).MethodsTwo-hundred non-duplicate P. aeruginosa strains isolated by 47 French medical laboratories were selected to cover a wide range of C/T and CZA MICs. Performance of C/T disc (30/10 μg, Bio-Rad), CZA discs (10/4 μg) (Thermo Fisher and Bio-Rad), C/T and CZA gradient tests (Etest, BioMérieux; MIC Test Strip, Liofilchem), and AST-XN12 card of Vitek 2 system (BioMérieux) were compared with a broth microdilution (BMD) method (Thermo Fisher). MIC and disc results w…
Comparative Genomics of Thalassobius Including the Description of Thalassobius activus sp. nov., and Thalassobius autumnalis sp. nov.
2018
A taxogenomic study was conducted to describe two new Thalassobius species and to analyze the internal consistency of the genus Thalassobius along with Shimia and Thalassococcus. Strains CECT 5113T, CECT 5114, CECT 5118T, and CECT 5120 were isolated from coastal Mediterranean seawater, Spain. Cells were Gram-negative, non- motile coccobacilli, aerobic chemoorganotrophs, with an optimum temperature of 26°C and salinity of 3.5–5%. Major cellular fatty acids of strains CECT 5113T and CECT 5114 were C18 : 1 ω7c/ω6c and C10 : 0 3OH, G+C content was 54.4–54.5 mol% and were able to utilize propionate, L-threonine, L- arginine, and L-aspartate as carbon sources. They exhibited 98.3% 16S rRNA gene s…
Improvement of a rapid direct blood culture microbial identification protocol using MALDI-TOF MS and performance comparison with SepsiTyper kit
2018
Fast diagnosis of pathogens is critical to guarantee the most adequate therapy for infections; bacterial culture methods, which constitute the actual gold standard, are precise and sensitive but rather slow. Today, new methods have been made available to enable faster diagnosis, with the Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry (MALDI-TOF MS) technique being the most promising. Even if simpler and faster than traditional bacterial culture methods, analysis of positive blood cultures via MALDI-TOF MS requires a preliminary extraction process of samples. In this study, we compared two extraction protocols for bacterial identification directly from positive …
The Use and Abuse of LexA by Mobile Genetic Elements
2016
The SOS response is an essential process for responding to DNA damage in bacteria. The expression of SOS genes is under the control of LexA, a global transcription factor that undergoes self-cleavage during stress to allow the expression of DNA repair functions and delay cell division until the damage is rectified. LexA also regulates genes that are not part of this cell rescue program, and the induction of bacteriophages, the movement of pathogenicity islands, and the expression of virulence factors and bacteriocins are all controlled by this important transcription factor. Recently it has emerged that when regulating the expression of genes from mobile genetic elements (MGEs), LexA often …
New Genes Involved in Mild Stress Response Identified by Transposon Mutagenesis in Lactobacillus paracasei
2018
International audience; Lactic acid bacteria (LAB) are associated with various plant, animal, and human niches and are also present in many fermented foods and beverages. Thus, they are subjected to several stress conditions and have developed advanced response mechanisms to resist, adapt, and grow. This work aimed to identify the genes involved in some stress adaptation mechanisms in LAB. For this purpose, global reverse genetics was applied by screening a library of 1287 Lactobacillus paracasei transposon mutants for mild monofactorial stresses. This library was submitted independently to heat (52 degrees C, 30 min), ethanol (170 g.L-1, 30 min), salt (NaCl 0.8 M, 24 h), acid (pH 4.5, 24 h…
Analysis of DNA Polymerases Reveals Specific Genes Expansion in Leishmania and Trypanosoma spp.
2020
Leishmaniasis and trypanosomiasis are largely neglected diseases prevailing in tropical and subtropical conditions. These are an arthropod-borne zoonosis that affects humans and some animals and is caused by infection with protozoan of the genera Leishmania and Trypanosoma, respectively. These parasites present high genomic plasticity and are able to adapt themselves to adverse conditions like the attack of host cells or toxicity induced by drug exposure. Different mechanisms allow these adapting responses induced by stress, such as mutation, chromosomal rearrangements, establishment of mosaic ploidies, and gene expansion. Here we describe how a subset of genes encoding for DNA polymerases …