NMR reveals the interplay between SilE and SilB model peptides in the context of silver resistance.
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ABSTRACT:
SUBMITTER: Babel L
PROVIDER: S-EPMC8686694 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Whereas generic, LC-based pharmaceutical control quality procedures depend largely on the detection mode and can be particularly 'blind' to certain impurities, NMR is a more versatile and, thus, often more judicious detector. While adulteration presents ever-evolving challenges for the analysis of active pharmaceutical ingredients (APIs) and finished products sold in the worldwide (online) marketplace, research chemicals are usually trusted rather than being considered flawed or even adulterated. This report shows how NMR analysis uncovered the unanticipated presence of substantial amounts of mannitol (20 and 43% w/w) as undeclared constituent in two custom synthetic peptides, DR and DRVYI, that were sourced commercially. Quantitative 1H NMR (qHNMR) readily detected the contaminant, even on a 60 MHz benchtop instrument, and quantified the highly polar and UV-transparent adulterant. Quantum-mechanical 1H iterative Full Spin Analysis (HiFSA) not only achieved unambiguous identification of both the mannitol and the peptides, but also confirmed the quantitative results. The cases show that experimental verification supersedes trust in both pharmaceutical and research QC. They also highlight the promising utility of both established high-field and recently re-evolving low-field benchtop qHNMR. The unanticipated findings remind manufacturers and researchers alike about the advantages of including/performing NMR and qNMR with routine CofA documentation and/or verification of research grade chemicals. Especially when done jointly, this can greatly improve confidence in research and help streamline the pharmaceutical QC toolbox.
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Project description:Recent research adds to a growing body of literature on the essential role of ceramides in glucose homeostasis and insulin signaling, while the mechanistic interplay between various components of ceramide metabolism remains to be quantified. We present an extended model of C16:0 ceramide production through both the de novo synthesis and the salvage pathways. We verify our model with a combination of published models and independent experimental data. In silico experiments of the behavior of ceramide and related bioactive lipids in accordance with the observed transcriptomic changes in obese/diabetic murine macrophages at 5 and 16 weeks support the observation of insulin resistance only at the later phase. Our analysis suggests the pivotal role of ceramide synthase, serine palmitoyltransferase and dihydroceramide desaturase involved in the de novo synthesis and the salvage pathways in influencing insulin resistance versus its regulation.
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Project description:Antimicrobial peptides (AMPs) are key effectors of the innate immune system and promising therapeutic agents. Yet, knowledge on how to design AMPs with minimal cross-resistance to human host-defense peptides remains limited. Here, we systematically assess the resistance determinants of Escherichia coli against 15 different AMPs using chemical-genetics and compare to the cross-resistance spectra of laboratory-evolved AMP-resistant strains. Although generalizations about AMP resistance are common in the literature, we find that AMPs with different physicochemical properties and cellular targets vary considerably in their resistance determinants. As a consequence, cross-resistance is prevalent only between AMPs with similar modes of action. Finally, our screen reveals several genes that shape susceptibility to membrane- and intracellular-targeting AMPs in an antagonistic manner. We anticipate that chemical-genetic approaches could inform future efforts to minimize cross-resistance between therapeutic and human host AMPs.
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Project description:This SuperSeries is composed of the SubSeries listed below. The experiments are described in 2 papers: PMID 30137431 and PMID 30507376
2018-06-11 | GSE104761 | GEO
Project description:Antibiotics are regarded as a miracle in the medical field as it prevents disease caused by pathogenic bacteria. Since the discovery of penicillin, antibiotics have become the foundation for modern medical discoveries. However, bacteria soon became resistant to antibiotics, which puts a burden on the healthcare system. Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most prominent antibiotic-resistant bacteria in the world since 1961. MRSA primarily developed resistance to beta-lactamases antibiotics and can be easily spread in the healthcare system. Thus, alternatives to combat MRSA are urgently required. Antimicrobial peptides (AMPs), an innate host immune agent and silver nanoparticles (AgNPs), are gaining interest as alternative treatments against MRSA. Both agents have broad-spectrum properties which are suitable candidates for controlling MRSA. Although both agents can exhibit antimicrobial effects independently, the combination of both can be synergistic and complementary to each other to exhibit stronger antimicrobial activity. The combination of AMPs and AgNPs also reduces their own weaknesses as their own, which can be developed as a potential agent to combat antibiotic resistance especially towards MRSA. Thus, this review aims to discuss the potential of antimicrobial peptides and silver nanoparticles towards controlling MRSA pathogen growth.
| S-EPMC9311968 | biostudies-literature
Project description:Colletotrichum lentis is a hemibiotrophic pathogen and causes anthracnose on lentil. To understand the molecular mechanism underlying the symptomatic phase of infection, a cDNA plasmid library was developed from the susceptible lentil cultivar Eston infected with an isolate of the virulent race 0 of C. lentis. The library was sequenced on the Sanger sequencing platform, generating a total of 11,094 expressed sequence tags (ESTs) representing 3,488 unigenes. Mapping of unigenes onto the C. lentis and the L. culinaris genomes resulted in the identification of 2,418 unigenes of fungal origin and 1,070 unigenes of plant origin. Gene ontology term analysis of unigenes revealed that the transcriptome contained 22 candidate effectors, such as in planta induced ToxB and CyanoVirin-N, and 26 resistance genes, including suppressor of npr1-1 constitutive 1 and dirigent. Comparative genomics analyses revealed that three of the candidate effectors are likely located in the subtelomeric regions, and two of them show no synteny with the closely related species C. higginsianum, suggesting genomic rearrangements, such as translocation during speciation to colonize different niches. The data suggest a complex molecular interplay between disease resistance proteins and effectors during compatible interaction in which the pathogen exploits defense responses mounted by the host.
| S-EPMC5301223 | biostudies-literature
Project description:PurposeThe aim of this study is to improve the anti-biofilm activity of antibiotics. We hypothesized that the antimicrobial peptide (AMP) complex of the host's immune system can be used for this purpose and examined the assumption on model biofilms.MethodsFLIP7, the AMP complex of the blowfly Calliphora vicina containing a combination of defensins, cecropins, diptericins and proline-rich peptides was isolated from the hemolymph of bacteria-challenged maggots. The complex interaction with antibiotics of various classes was studied in biofilm and planktonic cultures of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii by the checkerboard method using trimethyl tetrazolium chloride cell viability and crystal violet biofilm eradication assays supplemented with microscopic analysis.ResultsWe found that FLIP7 demonstrated: high synergy (fractional inhibitory concentration index <0.25) with meropenem, amikacin, kanamycin, ampicillin, vancomycin and cefotaxime; synergy with clindamycin, erythromycin and chloramphenicol; additive interaction with oxacillin, tetracycline, ciprofloxacin and gentamicin; and no interaction with polymyxin B. The interaction in planktonic cell models was significantly weaker than in biofilms of the same strains. The analysis of the dose-effect curves pointed to persister cells as a likely target of FLIP7 synergistic effect. The biofilm eradication assay showed that the effect also caused total destruction of S. aureus and E. coli biofilm materials. The effect allowed reducing the effective anti-biofilm concentration of the antibiotic to a level well below the one clinically achievable (2-3 orders of magnitude in the case of meropenem, ampicillin, cefotaxime and oxacillin).ConclusionFLIP7 is a highly efficient host antimicrobial system helping antibiotics to overcome biofilm barriers through persisters' sensitization and biofilm material destruction. It is promising for the treatment of biofilm infections as an adjuvant of various small-molecule antibiotics.
| S-EPMC5898886 | biostudies-literature
Project description:Transcription factors show rapid and reversible binding to chromatin in living cells, and transcription occurs in sporadic bursts, but how these phenomena are related is unknown. Using a combination of in vitro and in vivo single-molecule imaging approaches, we directly correlated binding of the Gal4 transcription factor with the transcriptional bursting kinetics of the Gal4 target genes GAL3 and GAL10 in living yeast cells. We find that Gal4 dwell time sets the transcriptional burst size. Gal4 dwell time depends on the affinity of the binding site and is reduced by orders of magnitude by nucleosomes. Using a novel imaging platform called orbital tracking, we simultaneously tracked transcription factor binding and transcription at one locus, revealing the timing and correlation between Gal4 binding and transcription. Collectively, our data support a model in which multiple RNA polymerases initiate transcription during one burst as long as the transcription factor is bound to DNA, and bursts terminate upon transcription factor dissociation.
| S-SCDT-EMBOJ-2018-100809 | biostudies-other
Project description:PurposeWe undertook a study to identify conditions and operational changes linked to improvements in smoking and blood pressure (BP) outcomes in primary care.MethodsWe purposively sampled and interviewed practice staff (eg, office managers, clinicians) from a subset of 104 practices participating in EvidenceNOW-a multisite cardiovascular disease prevention initiative. We calculated Clinical Quality Measure improvements, with targets of 10-point or greater absolute improvements in the proportion of patients with smoking screening and, if relevant, counseling and in the proportion of hypertensive patients with adequately controlled BP. We analyzed interview data to identify operational changes, transforming these into numeric data. We used Configurational Comparative Methods to assess the joint effects of multiple factors on outcomes.ResultsIn clinician-owned practices, implementing a workflow to routinely screen, counsel, and connect patients to smoking cessation resources, or implementing a documentation change or a referral to a resource alone led to an improvement of at least 10 points in the smoking outcome with a moderate level of facilitation support. These patterns did not manifest in health- or hospital system-owned practices or in Federally Qualified Health Centers, however. The BP outcome improved by at least 10 points among solo practices after medical assistants were trained to take an accurate BP. Among larger, clinician-owned practices, BP outcomes improved when practices implemented a second BP measurement when the first was elevated, and when staff learned where to document this information in the electronic health record. With 50 hours or more of facilitation, BP outcomes improved among larger and health- and hospital system-owned practices that implemented these operational changes.ConclusionsThere was no magic bullet for improving smoking or BP outcomes. Multiple combinations of operational changes led to improvements, but only in specific contexts of practice size and ownership, or dose of external facilitation.
| S-EPMC8118489 | biostudies-literature
Project description:Antimicrobial peptides (AMPs) are promising antimicrobials, however, the potential of bacterial resistance is a major concern. Here we systematically study the evolution of resistance to 14 chemically diverse AMPs and 12 antibiotics in Escherichia coli. Our work indicates that evolution of resistance against certain AMPs, such as tachyplesin II and cecropin P1, is limited. Resistance level provided by point mutations and gene amplification is very low and antibiotic-resistant bacteria display no cross-resistance to these AMPs. Moreover, genomic fragments derived from a wide range of soil bacteria confer no detectable resistance against these AMPs when introduced into native host bacteria on plasmids. We have found that simple physicochemical features dictate bacterial propensity to evolve resistance against AMPs. Our work could serve as a promising source for the development of new AMP-based therapeutics less prone to resistance, a feature necessary to avoid any possible interference with our innate immune system.
| S-EPMC6778101 | biostudies-literature