DNA simulation
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UNLABELLED: The aim of this study was to identify parameters influencing DNA extraction and PCR amplification efficiencies in an attempt to standardize Mucorales qPCR. The Fungal PCR Initiative Mucorales Laboratory Working Group distributed two panels of simulated samples to 26 laboratories: Panel A (six sera spiked with Mucorales DNA and one negative control serum) and Panel B (six Mucorales DNA extracts). Panel A underwent DNA extraction in each laboratory according to the local procedure and were sent to a central laboratory for testing using three different qPCR techniques: one in-house qPCR assay and two commercial assays (MucorGenius and Fungiplex). Panel B DNA extracts were PCR amplified in each laboratory using local procedures: nine in-house qPCR assays and two commercial kits (MucorGenius and MycoGENIE). All data were compiled and anonymously analyzed at the central laboratory. For Panel A, a total of six different automated platforms and five manual extraction methods were used. Positive rates were 64%, 70%, and 89%, for the MucorGenius, Fungiplex, and the in-house qPCR assay, respectively. Using a large volume of serum for DNA extraction provided the highest analytical sensitivity (82.5% for 1 mL compared with 62.7% for smaller volumes, P < 0.01). For Panel B, five in-house qPCR assays and two commercial kits had >78% positivity. Using larger PCR input volumes (≥7 μL) was associated with the highest sensitivity at 95.5% compared to 58.3% when lower input volumes were used (P < 0.01). Using larger sample volumes for nucleic acid extraction and DNA template volumes for PCR amplification significantly improves the performance of Mucorales qPCR when testing serum. IMPORTANCE: Mucormycosis is a life-threatening mold infection affecting immunosuppressed patients but also other patients with diabetes or trauma. Better survival is linked to shorter delays in diagnosis and treatment initiation. Detection of Mucorales-free DNA in serum or plasma using quantitative PCR allows a prompt diagnosis and earlier treatment. Several techniques and protocols of quantitative Mucorales PCR are used in Europe, and improving performance remains a common objective of laboratories participating in the fungal PCR Initiative Working Group. This study, which combined results from 26 laboratories in Europe, showed that the main parameters underpinning sensitivity are the preanalytical variables (volume of serum used for DNA extraction and DNA template volume), irrespective of the extraction platforms and qPCR assay/platform.
- MeSH
- diagnostické techniky molekulární normy metody MeSH
- DNA fungální * krev genetika MeSH
- kvantitativní polymerázová řetězová reakce * normy metody MeSH
- lidé MeSH
- Mucorales * genetika izolace a purifikace MeSH
- mukormykóza * diagnóza mikrobiologie krev MeSH
- senzitivita a specificita * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Integral membrane proteins carry out essential functions in the cell, and their activities are often modulated by specific protein-lipid interactions in the membrane. Here, we elucidate the intricate role of cardiolipin (CDL), a regulatory lipid, as a stabilizer of membrane proteins and their complexes. Using the in silico-designed model protein TMHC4_R (ROCKET) as a scaffold, we employ a combination of molecular dynamics simulations and native mass spectrometry to explore the protein features that facilitate preferential lipid interactions and mediate stabilization. We find that the spatial arrangement of positively charged residues as well as local conformational flexibility are factors that distinguish stabilizing from non-stabilizing CDL interactions. However, we also find that even in this controlled, artificial system, a clear-cut distinction between binding and stabilization is difficult to attain, revealing that overlapping lipid contacts can partially compensate for the effects of binding site mutations. Extending our insights to naturally occurring proteins, we identify a stabilizing CDL site within the E. coli rhomboid intramembrane protease GlpG and uncover its regulatory influence on enzyme substrate preference. In this work, we establish a framework for engineering functional lipid interactions, paving the way for the design of proteins with membrane-specific properties or functions.
- MeSH
- DNA vazebné proteiny MeSH
- endopeptidasy metabolismus chemie genetika MeSH
- Escherichia coli metabolismus genetika MeSH
- kardiolipiny * metabolismus chemie MeSH
- membránové proteiny * metabolismus chemie genetika MeSH
- proteinové inženýrství * MeSH
- proteiny z Escherichia coli * metabolismus chemie genetika MeSH
- simulace molekulární dynamiky MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
Investigation determines the beneficial effect of bergaptol against gestational diabetes (GD). Gestational diabetes was induced in female rats and treated them with bergaptol 20 and 40 mg/kg for eighteen days. Effect of bergaptol was assessed on blood glucose and insulin level in GD rat. Inflammatory mediators and oxidative stress parameters were also assessed in GD rats. Moreover, mRNA expression of INSR, NF-kappaB, Akt and GSK-3beta were assessed in the GD rats by qRT-PCR method. In silico network pharmacology study was performed, along with gene ontology and egg pathway to assessed the targets of bergaptol, molecular docking study was also performed for the confirmation of possible pathway involved in the management of GD. Blood glucose and insulin level was significantly reduces in the blood bergaptol treated group than GD group of rats. Treatment with bergaptol ameliorates the altered level of mediators of inflammation and oxidative stress parameters in GD rats. There was significant reduction in the mRNA expression of NF-kappaB and GSK-3beta and increase in expression of INSR and Akt in the tissue homogenate of bergaptol treated GD rats. Docking study shows effective binding strength of bergaptol individually with INSR, NF-kappaB, Akt and GSK-3beta-protein targets. In conclusion, data of investigation suggest that bergaptol improves the sensitivity of insulin receptor in GD, as it reduces parameters of oxidative stress and inflammatory mediators by regulating INSR/NF-kappaB/Akt/GSK-3beta pathway. Key words Gestational diabetes, Bergaptol, Insulin resistance, Inflammation, Oxidative stress.
- MeSH
- experimentální diabetes mellitus * farmakoterapie metabolismus MeSH
- gestační diabetes * farmakoterapie metabolismus MeSH
- inzulinová rezistence * fyziologie MeSH
- kinasa glykogensynthasy 3beta metabolismus MeSH
- krevní glukóza metabolismus účinky léků MeSH
- krysa rodu rattus MeSH
- oxidační stres účinky léků MeSH
- potkani Wistar MeSH
- receptor inzulinu metabolismus MeSH
- signální transdukce účinky léků MeSH
- simulace molekulového dockingu * MeSH
- těhotenství MeSH
- zánět farmakoterapie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The activity of the light-oxygen-voltage/helix-turn-helix (LOV-HTH) photoreceptor EL222 is regulated through protein-protein and protein-DNA interactions, both triggered by photo-excitation of its flavin mononucleotide (FMN) cofactor. To gain molecular-level insight into the photocycle of EL222, we applied complementary methods: macromolecular X-ray crystallography (MX), nuclear magnetic resonance (NMR) spectroscopy, optical spectroscopies (infrared and UV-visible), molecular dynamics/metadynamics (MD/metaD) simulations, and protein engineering using noncanonical amino acids. Kinetic experiments provided evidence for two distinct EL222 conformations (lit1 and lit2) that become sequentially populated under illumination. These two lit states were assigned to covalently bound N5 protonated, and noncovalently bound hydroquinone forms of FMN, respectively. Only subtle structural differences were observed between the monomeric forms of all three EL222 species (dark, lit1, and lit2). While the dark state is largely monomeric, both lit states undergo monomer-dimer exchange. Furthermore, molecular modeling revealed differential dynamics and interdomain separation times arising from the three FMN states (oxidized, adduct, and reduced). Unexpectedly, all three EL222 species can associate with DNA, but only upon blue-light irradiation, a high population of stable complexes is obtained. Overall, we propose a model of EL222 activation where photoinduced changes in the FMN moiety shift the population equilibrium toward an open conformation that favors self-association and DNA-binding.
- MeSH
- bakteriální proteiny chemie metabolismus MeSH
- DNA vazebné proteiny chemie metabolismus MeSH
- DNA * chemie metabolismus MeSH
- flavinmononukleotid * chemie metabolismus MeSH
- flaviny chemie metabolismus MeSH
- kinetika MeSH
- konformace proteinů MeSH
- krystalografie rentgenová MeSH
- oxidace-redukce * MeSH
- simulace molekulární dynamiky MeSH
- světlo * MeSH
- Thermosynechococcus metabolismus MeSH
- transkripční faktory metabolismus chemie MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
We present new developments for an ab-initio model of the neutron relative biological effectiveness (RBE) in inducing specific classes of DNA damage. RBE is evaluated as a function of the incident neutron energy and of the depth inside a human-sized reference spherical phantom. The adopted mechanistic approach traces neutron RBE back to its origin, i.e. neutron physical interactions with biological tissues. To this aim, we combined the simulation of radiation transport through biological matter, performed with the Monte Carlo code PHITS, and the prediction of DNA damage using analytical formulas, which ground on a large database of biophysical radiation track structure simulations performed with the code PARTRAC. In particular, two classes of DNA damage were considered: sites and clusters of double-strand breaks (DSBs), which are known to be correlated with cell fate following radiation exposure. Within a coherent modelling framework, this approach tackles the variation of neutron RBE in a wide energy range, from thermal neutrons to neutrons of hundreds of GeV, and reproduces effects related to depth in the human-sized receptor, as well as to the receptor size itself. Besides providing a better mechanistic understanding of neutron biological effectiveness, the new model can support better-informed decisions for radiation protection: indeed, current neutron weighting (ICRP)/quality (U.S. NRC) factors might be insufficient for use in some radiation protection applications, because they do not account for depth. RBE predictions obtained with the reported model were successfully compared to the currently adopted radiation protection standards when the depth information is not relevant (at the shallowest depth in the phantom or for very high energy neutrons). However, our results demonstrate that great care is needed when applying weighting factors as a function of incident neutron energy only, not explicitly considering RBE variation in the target. Finally, to facilitate the use of our results, we propose look-up RBE tables, explicitly considering the depth variable, and an analytical representation of the maximal RBE vs. neutron energy.
The ReAct (Recovery, Activity) project is an ENFSI (European Network of Forensic Science Institutes) supported initiative comprising a large consortium of laboratories. Here, the results from more than 23 laboratories are presented. The primary purpose was to design experiments simulating typical casework circumstances; collect data and to implement Bayesian networks to assess the value (i.e., likelihood ratio) of DNA results given activity level propositions. Two different experimental designs were used to simulate a robbery, where a screwdriver was used to force a door or window. Propositions and case information were chosen following laboratory feedback listing typical casework circumstances (included in the paper). In a direct transfer experiment, the defendant owned and used the screwdriver, but he did not force the door/window in question. An unknown person used the defendant's stolen screwdriver. In an indirect transfer experiment, the defendant neither owned, saw, nor used the screwdriver, nor did they force the door or window. For the second experiment, given the defence view, the defendant never held the screwdriver. We envisaged the situation where an object manipulated by the defendant (or the defendant himself/herself) would be touched by the unknown offender who would then force the window. It was found for the direct transfer experiment that unless a single contributor profile aligning with the known person's of interest profile was retrieved, the results did not allow to discriminate between propositions. On the other hand, for the indirect transfer experiment, both single and major contributor profiles that aligned with the person of interest (POI) supported the proposition that the person used the tool rather than an unknown person who had touched an object, when indeed the former was true. There was considerable variation in median recoveries of DNA between laboratories (between 200pg-5ng) for a given experiment if quantities are taken into account. These differences affect the likelihood ratios given activity level propositions. More than 2700 samples were analysed in the course of this study. Two different Bayesian Networks are made available via an open source application written in Shiny R: Shiny_React(). For comparison, all datasets were analysed using a qualitative method categorised into absent, single, major or other given contributors. The importance of standardising methods is emphasised, alongside the necessity of developing new approaches to assign the probability of laboratory-dependent DNA recovery. Freely accessible open databases play a crucial role in supporting these efforts.
- MeSH
- Bayesova věta * MeSH
- DNA fingerprinting * MeSH
- DNA * genetika MeSH
- laboratoře * MeSH
- lidé MeSH
- mikrosatelitní repetice MeSH
- pravděpodobnostní funkce MeSH
- soudní genetika metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
NASA has encouraged studies on 226Ra deposition in the human brain to investigate the effects of exposure to alpha particles with high linear energy transfer, which could mimic some of the exposure astronauts face during space travel. However, this approach was criticized, noting that radium is a bone-seeker and accumulates in the skull, which means that the radiation dose from alpha particles emitted by 226Ra would be heavily concentrated in areas close to cranial bones rather than uniformly distributed throughout the brain. In the high background radiation areas of Ramsar, Iran, extremely high levels of 226Ra in soil contribute to a large proportion of the inhabitants' radiation exposure. A prospective study on Ramsar residents with a calcium-rich diet was conducted to improve the dose uniformity due to 226Ra throughout the cerebral and cerebellar parenchyma. The study found that exposure of the human brain to alpha particles did not significantly affect working memory but was significantly associated with increased reaction times. This finding is crucial because astronauts on deep space missions may face similar cognitive impairments due to exposure to high charge and energy particles. The current study was aimed to evaluate the validity of the terrestrial model using the Geant4 Monte Carlo toolkit to simulate the interactions of alpha particles and representative cosmic ray particles, acknowledging that these radiation types are only a subset of the complete space radiation environment.
- MeSH
- DNA MeSH
- lidé MeSH
- lineární přenos energie MeSH
- metoda Monte Carlo MeSH
- mozek MeSH
- prospektivní studie MeSH
- radium * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
We currently lack antivirals for most human viruses. In a quest for new molecules, focusing on viral RNA, instead of viral proteins, can represent a promising strategy. In this study, new inhibitors were identified starting from a published crystal structure of the tertiary SARS-CoV-2 RNA involved in the -1 programmed ribosomal frameshift. The pseudoknot structure was refined, and a virtual screening was performed using the repository of binders to the nucleic acid library, taking into consideration RNA flexibility. Hit compounds were validated against the wild-type virus and with a dual-luciferase assay measuring the frameshift efficiency. Several active molecules were identified. Our study reveals new inhibitors of SARS-CoV-2 but also highlights the feasibility of targeting RNA starting from virtual screening, a strategy that could be broadly applied to drug development.
- MeSH
- antivirové látky * farmakologie chemie MeSH
- konformace nukleové kyseliny MeSH
- lidé MeSH
- molekulární modely MeSH
- preklinické hodnocení léčiv * metody MeSH
- RNA virová * metabolismus antagonisté a inhibitory genetika MeSH
- SARS-CoV-2 * účinky léků MeSH
- simulace molekulového dockingu MeSH
- uživatelské rozhraní počítače MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Aim: Today, there is a lack of research studies concerning human acute exposure to nanoparticles (NPs). Our investigation aimed to simulate real-world acute inhalation exposure to NPs released during work with dental nanocomposites in a dental office or technician laboratory. Methods: Blood samples from female volunteers were processed before and after inhalation exposure. Transcriptomic mRNA and miRNA expression changes were analyzed. Results: We detected large interindividual variability, 90 significantly deregulated mRNAs, and 4 miRNAs when samples of participants before and after dental nanocomposite grinding were compared. Conclusion: The results suggest that inhaled dental NPs may present an occupational hazard to human health, as indicated by the changes in the processes related to oxidative stress, synthesis of eicosanoids, and cell division.
- MeSH
- dospělí MeSH
- inhalační expozice * škodlivé účinky MeSH
- lidé MeSH
- messenger RNA genetika MeSH
- mikro RNA * genetika MeSH
- nanočástice chemie MeSH
- nanokompozity * chemie MeSH
- oxidační stres účinky léků MeSH
- pracovní expozice škodlivé účinky MeSH
- transkriptom * účinky léků MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The single-stranded RNA genome of SARS-CoV-2 is highly structured. Numerous helical stem-loop structures interrupted by mismatch motifs are present in the functionally important 5'- and 3'-UTRs. These mismatches modulate local helical geometries and feature unusual arrays of hydrogen bonding donor and acceptor groups. However, their conformational and dynamical properties cannot be directly inferred from chemical probing and are difficult to predict theoretically. A mismatch motif (SL1-motif) consisting of three consecutive U•U base pairs is located in stem-loop 1 of the 3'-UTR. We combined NMR-spectroscopy and MD-simulations to investigate its structure and dynamics. All three U•U base pairs feature two direct hydrogen bonds and are as stable as Watson-Crick A:U base pairs. Plasmodium falciparum 25S rRNA contains a triple U•U mismatch motif (Pf-motif) differing from SL1-motif only with respect to the orientation of the two closing base pairs. Interestingly, while the geometry of the outer two U•U mismatches was identical in both motifs the preferred orientation of the central U•U mismatch was different. MD simulations and potassium ion titrations revealed that the potassium ion-binding mode to the major groove is connected to the different preferred geometries of the central base pair in the two motifs.
- MeSH
- 3' nepřekládaná oblast * MeSH
- chybné párování bází * MeSH
- COVID-19 virologie MeSH
- genom virový MeSH
- konformace nukleové kyseliny MeSH
- lidé MeSH
- nukleotidové motivy * MeSH
- párování bází MeSH
- Plasmodium falciparum genetika MeSH
- RNA virová * chemie genetika MeSH
- SARS-CoV-2 * genetika chemie MeSH
- simulace molekulární dynamiky MeSH
- vodíková vazba MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH