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1.
R Soc Open Sci ; 11(6): 240498, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-39100192

RESUMEN

We live at a time of rapid and accelerating biodiversity loss and climate change that pose an existential risk to the environment, humanity, and social justice and stability. Governmental responses are seen by many citizens, including scientists, as inadequate, leading to an increase in civil protests and activism by those calling for urgent action to effect change. Here we consider the role(s) of scientists in responding to those challenges and engaging with policy given that when a scientist moves into political advocacy, reflecting their values and preferences, their objectivity and the value of scientific opinion may be seen as compromised. We then consider whether institutional setting and career stage may affect decisions to engage with policy or activism. Against this backcloth, we ask whether it is sufficient for scientists to act as impartial 'brokers' in societal decisions, arguing they should consider acting as 'Honest Advocates' in policy formation in some circumstances. Such advocacy can contribute to decision-making in a purposeful, well-informed manner, doing societal good without damaging the reputation of science. We encourage scientists to each reflect on their multiple roles in addressing the environmental challenges of our time.

2.
Nat Commun ; 15(1): 5775, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38982125

RESUMEN

The epitranscriptome includes a diversity of RNA modifications that influence gene expression. N3-methylcytidine (m3C) mainly occurs in the anticodon loop (position C32) of certain tRNAs yet its role is poorly understood. Here, using HAC-Seq, we report comprehensive METTL2A/2B-, METTL6-, and METTL2A/2B/6-dependent m3C profiles in human cells. METTL2A/2B modifies tRNA-arginine and tRNA-threonine members, whereas METTL6 modifies the tRNA-serine family. However, decreased m3C32 on tRNA-Ser-GCT isodecoders is only observed with combined METTL2A/2B/6 deletion. Ribo-Seq reveals altered translation of genes related to cell cycle and DNA repair pathways in METTL2A/2B/6-deficient cells, and these mRNAs are enriched in AGU codons that require tRNA-Ser-GCT for translation. These results, supported by reporter assays, help explain the observed altered cell cycle, slowed proliferation, and increased cisplatin sensitivity phenotypes of METTL2A/2B/6-deficient cells. Thus, we define METTL2A/2B/6-dependent methylomes and uncover a particular requirement of m3C32 tRNA modification for serine codon-biased mRNA translation of cell cycle, and DNA repair genes.


Asunto(s)
Ciclo Celular , Codón , Daño del ADN , Biosíntesis de Proteínas , ARN Mensajero , ARN de Transferencia , Serina , Humanos , Ciclo Celular/genética , Codón/genética , ARN Mensajero/metabolismo , ARN Mensajero/genética , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Serina/metabolismo , Metiltransferasas/metabolismo , Metiltransferasas/genética , Citidina/análogos & derivados , Citidina/metabolismo , Citidina/genética , Reparación del ADN , Células HEK293 , Anticodón/genética
3.
J Oral Implantol ; 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39023858

RESUMEN

During implant maintenance, preserving a smooth surface on the machined trans-mucosa abutment is critical to reduce biofilm attachment and colonization. The present study compare the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined Grade 23 titanium discs were instrumented with a round Polyether Ether Ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units (CFU)/mL were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared to the other groups. Thisresulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness. SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared to discs instrumented with plastic or PEEK tip, despite the possibility of debris from tip dissolution. Our results suggested that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increase machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion.

4.
Pediatr Dent ; 46(3): 199-203, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38822496

RESUMEN

Purpose: The purposes of this in vitro study were to evaluate the effect of three isolation methods to mitigate bioaerosols during stainless steel crown (SSC) preparations and assess the distribution of Streptococcus mutans by aerosolization in closed-room operatories. Methods: Melamine teeth coated in laboratory-grown S. mutans biofilm were prepared for SSCs using three different isolation methods. Agar plates were placed in five locations throughout the operatory and opened during each preparation as well as for 10 minutes immediately following to collect aerosolized S. mutans. Bacterial colonies were counted after incubating plates for 48 hours. Data were analyzed for differences between the isolation method and plate locations. Results: Bacterial colony counts for teeth prepared using high-volume evacuation suction (HVE) with dental dam (DD) isolation were statistically significantly higher than for those prepared using HVE with a DryShield®(DS) and HVE with no isolation at the assistant (A) (P<0.001), operator face shield (FS) (P<0.001), and patient (Pt) (P=0.002) locations. No significant differences were found among isolation methods for parent (Pa) or rear delivery (RD) locations. The location that produced the most bacterial colony counts using HVE with DD isolation was FS (P<0.001), followed by A (P=0.04), Pt (P<0.001), and RD and Pa (P<0.001). Counts produced from teeth prepared with DS isolation were significantly higher at the Pt location than the A (P<0.001), FS (P=0.002), RD (P<0.001), and Pa (P=0.008) locations. Conclusion: The use of dental dam with high-volume evacuation suction during stainless steel crown preparations increased bioaerosols near the procedure, while dental evacuation systems (DryShield®) may effectively limit their spread.


Asunto(s)
Aerosoles , Streptococcus mutans , Humanos , Streptococcus mutans/aislamiento & purificación , Acero Inoxidable , Coronas , Técnicas In Vitro , Microbiología del Aire , Recuento de Colonia Microbiana , Biopelículas , Carga Bacteriana , Succión/instrumentación , Control de Infección Dental/métodos
5.
Cancer Med ; 13(5)2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38501219

RESUMEN

Mivavotinib (TAK-659/CB-659), a dual SYK/FLT3 inhibitor, reduced immunosuppressive immune cell populations and suppressed tumor growth in combination with anti-PD-1 therapy in cancer models. This dose-escalation/expansion study investigated the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of mivavotinib plus nivolumab in patients with advanced solid tumors. Patients received oral mivavotinib 60-100 mg once-daily plus intravenous nivolumab 3 mg/kg on days 1 and 15 in 28-day cycles until disease progression or unacceptable toxicity. The dose-escalation phase evaluated the recommended phase II dose (RP2D; primary endpoint). The expansion phase evaluated overall response rate (primary end point) at the RP2D in patients with triple-negative breast cancer (TNBC). During dose-escalation (n = 24), two dose-limiting toxicities (grade 4 lipase increased and grade 3 pyrexia) occurred in patients who received mivavotinib 80 mg and 100 mg, respectively. The determined RP2D was once-daily mivavotinib 80 mg plus nivolumab 3 mg/kg. The expansion phase was terminated at ~50% enrollment (n = 17) after failing to meet an ad hoc efficacy futility threshold. Among all 41 patients, common treatment-emergent adverse events (TEAEs) included dyspnea (48.8%), aspartate aminotransferase increased, and pyrexia (46.3% each). Common grade ≥3 TEAEs were hypophosphatemia and anemia (26.8% each). Mivavotinib plasma exposure was generally dose-proportional (60-100 mg). One patient had a partial response. Mivavotinib 80 mg plus nivolumab 3 mg/kg was well tolerated with no new safety signals beyond those of single-agent mivavotinib or nivolumab. Low response rates highlight the challenges of treating unresponsive tumor types, such as TNBC, with this combination and immunotherapies in general. TRIAL REGISTRATION ID: NCT02834247.


Asunto(s)
Nivolumab , Neoplasias de la Mama Triple Negativas , Humanos , Ensayos Clínicos Fase II como Asunto , Fiebre , Nivolumab/efectos adversos , Inhibidores de Proteínas Quinasas , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Femenino
6.
BMJ Case Rep ; 16(11)2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37914174

RESUMEN

Mesenteric panniculitis is a non-neoplastic condition involving inflammation and fibrosis of the small bowel mesentery. We describe a man in his 60s who presented with 3 months of febrile episodes, confusion and weight loss. The diagnosis of mesenteric panniculitis had been established 2 weeks prior based on an abdominal computerized tomography scan. Extensive diagnostic investigations during his hospitalisation were unrevealing, and the symptoms were ultimately attributed to the mesenteric panniculitis. The fevers resolved over several weeks, and no further episodes have occurred since discharge. This case suggests that mesenteric panniculitis merits consideration in the differential diagnosis of fever of unknown origin.


Asunto(s)
Fiebre de Origen Desconocido , Paniculitis Peritoneal , Humanos , Masculino , Abdomen/diagnóstico por imagen , Diagnóstico Diferencial , Fiebre de Origen Desconocido/etiología , Fiebre de Origen Desconocido/diagnóstico , Paniculitis Peritoneal/diagnóstico , Paniculitis Peritoneal/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Persona de Mediana Edad
7.
Water Res ; 247: 120804, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37925861

RESUMEN

The world has moved into a new stage of managing the SARS-CoV-2 pandemic with minimal restrictions and reduced testing in the population, leading to reduced genomic surveillance of virus variants in individuals. Wastewater-based epidemiology (WBE) can provide an alternative means of tracking virus variants in the population but decision-makers require confidence that it can be applied to a national scale and is comparable to individual testing data. We analysed 19,911 samples from 524 wastewater sites across England at least twice a week between November 2021 and February 2022, capturing sewage from >70% of the English population. We used amplicon-based sequencing and the phylogeny based de-mixing tool Freyja to estimate SARS-CoV-2 variant frequencies and compared these to the variant dynamics observed in individual testing data from clinical and community settings. We show that wastewater data can reconstruct the spread of the Omicron variant across England since November 2021 in close detail and aligns closely with epidemiological estimates from individual testing data. We also show the temporal and spatial spread of Omicron within London. Our wastewater data further reliably track the transition between Omicron subvariants BA1 and BA2 in February 2022 at regional and national levels. Our demonstration that WBE can track the fast-paced dynamics of SARS-CoV-2 variant frequencies at a national scale and closely match individual testing data in time shows that WBE can reliably fill the monitoring gap left by reduced individual testing in a more affordable way.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Aguas Residuales , Monitoreo Epidemiológico Basado en Aguas Residuales , COVID-19/epidemiología , Genómica , Inglaterra/epidemiología
8.
Proc Natl Acad Sci U S A ; 120(21): e2216573120, 2023 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-37186854

RESUMEN

Declines in European bird populations are reported for decades but the direct effect of major anthropogenic pressures on such declines remains unquantified. Causal relationships between pressures and bird population responses are difficult to identify as pressures interact at different spatial scales and responses vary among species. Here, we uncover direct relationships between population time-series of 170 common bird species, monitored at more than 20,000 sites in 28 European countries, over 37 y, and four widespread anthropogenic pressures: agricultural intensification, change in forest cover, urbanisation and temperature change over the last decades. We quantify the influence of each pressure on population time-series and its importance relative to other pressures, and we identify traits of most affected species. We find that agricultural intensification, in particular pesticides and fertiliser use, is the main pressure for most bird population declines, especially for invertebrate feeders. Responses to changes in forest cover, urbanisation and temperature are more species-specific. Specifically, forest cover is associated with a positive effect and growing urbanisation with a negative effect on population dynamics, while temperature change has an effect on the dynamics of a large number of bird populations, the magnitude and direction of which depend on species' thermal preferences. Our results not only confirm the pervasive and strong effects of anthropogenic pressures on common breeding birds, but quantify the relative strength of these effects stressing the urgent need for transformative changes in the way of inhabiting the world in European countries, if bird populations shall have a chance of recovering.


Asunto(s)
Agricultura , Bosques , Animales , Granjas , Europa (Continente) , Dinámica Poblacional , Aves/fisiología , Biodiversidad , Ecosistema , Conservación de los Recursos Naturales
9.
Science ; 380(6645): 591-592, 2023 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-37167383

Asunto(s)
Biodiversidad
10.
Philos Trans R Soc Lond B Biol Sci ; 378(1881): 20220198, 2023 07 17.
Artículo en Inglés | MEDLINE | ID: mdl-37246375

RESUMEN

Detecting biodiversity change and identifying its causes is challenging because biodiversity is multifaceted and temporal data often contain bias. Here, we model temporal change in species' abundance and biomass by using extensive data describing the population sizes and trends of native breeding birds in the United Kingdom (UK) and the European Union (EU). In addition, we explore how species' population trends vary with species' traits. We demonstrate significant change in the bird assemblages of the UK and EU, with substantial reductions in overall bird abundance and losses concentrated in a relatively small number of abundant and smaller sized species. By contrast, rarer and larger birds had generally fared better. Simultaneously, overall avian biomass had increased very slightly in the UK and was stable in the EU, indicating a change in community structure. Abundance trends across species were positively correlated with species' body mass and with trends in climate suitability, and varied with species' abundance, migration strategy and niche associations linked to diet. Our work highlights how changes in biodiversity cannot be captured easily by a single number; care is required when measuring and interpreting biodiversity change given that different metrics can provide very different insights. This article is part of the theme issue 'Detecting and attributing the causes of biodiversity change: needs, gaps and solutions'.


Asunto(s)
Biodiversidad , Cambio Climático , Animales , Biomasa , Reino Unido , Aves , Ecosistema
11.
J Appl Biomater Funct Mater ; 21: 22808000221131892, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37051725

RESUMEN

BACKGROUND: Streptococcus mutans (S. mutans) participates in the dental caries process. Titanium dioxide (TiO2) nanoparticles produce reactive oxygen species capable of disrupting bacterial DNA synthesis by creating pores in cell walls and membranes. OBJECTIVE: The objective of this study was to determine the effect of TiO2 on the disruption of S. mutans biofilm. METHODS: This study was conducted in four phases involving a TiO2-containing toothbrush and TiO2 nanoparticles. Each phase was completed using 24 h established S. mutans biofilm growth. Phase one data was collected through a bacterial plating study, assessing biofilm viability. Biofilm mass was evaluated in phase two of the study by measuring S. mutans biofilm grown on microtiter plates following crystal violet staining. The third phase of the study involved a generalized oxygen radical assay to determine the relative amount of oxygen radicals released intracellularly. Phase four of the study included the measurement of insoluble glucan/extracellular polysaccharide (EPS) synthesis using a phenol-sulfuric acid assay. RESULTS: Both exposure time and time intervals had a significant effect on bacterial viability counts (p = 0.0323 and p = 0.0014, respectively). Bacterial counts after 6 min of exposure were significantly lower than after 2 min (p = 0.034), compared to the no treatment control (p = 0.0056). As exposure time increased, the amount of remaining biofilm mass was statistically lower than the no treatment control. Exposure time had a significant effect on oxygen radical production. Both the 30 and 100 nm TiO2 nanoparticles had a significant effect on bacterial mass. The silver nanoparticles and the 30 and 100 nm TiO2 nanoparticles significantly inhibited EPS production. CONCLUSION: The TiO2-containing toothbrush kills, disrupts, and produces oxygen radicals that disrupt established S. mutans biofilm. TiO2 and silver nanoparticles inhibit EPS production and reduce biofilm mass. The addition of TiO2 to dental products may be effective in reducing cariogenic dental biofilm.


Asunto(s)
Caries Dental , Nanopartículas del Metal , Humanos , Streptococcus mutans , Especies Reactivas de Oxígeno/metabolismo , Plata/farmacología , Biopelículas
12.
Biomed Res Int ; 2023: 8728499, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37096222

RESUMEN

Background: Peri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants. Methods: Biofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants. Results: Three-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm. Conclusion: While early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.


Asunto(s)
Implantes Dentales , Periimplantitis , Humanos , Titanio , Biopelículas , Propiedades de Superficie
13.
Nature ; 613(7943): 391-397, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36599985

RESUMEN

Chemical modifications of RNA have key roles in many biological processes1-3. N7-methylguanosine (m7G) is required for integrity and stability of a large subset of tRNAs4-7. The methyltransferase 1-WD repeat-containing protein 4 (METTL1-WDR4) complex is the methyltransferase that modifies G46 in the variable loop of certain tRNAs, and its dysregulation drives tumorigenesis in numerous cancer types8-14. Mutations in WDR4 cause human developmental phenotypes including microcephaly15-17. How METTL1-WDR4 modifies tRNA substrates and is regulated remains elusive18. Here we show,  through structural, biochemical and cellular studies of human METTL1-WDR4, that WDR4 serves as a scaffold for METTL1 and the tRNA T-arm. Upon tRNA binding, the αC region of METTL1 transforms into a helix, which together with the α6 helix secures both ends of the tRNA variable loop. Unexpectedly, we find that the predicted disordered N-terminal region of METTL1 is part of the catalytic pocket and essential for methyltransferase activity. Furthermore, we reveal that S27 phosphorylation in the METTL1 N-terminal region inhibits methyltransferase activity by locally disrupting the catalytic centre. Our results provide a molecular understanding of tRNA substrate recognition and phosphorylation-mediated regulation of METTL1-WDR4, and reveal the presumed disordered N-terminal region of METTL1 as a nexus of methyltransferase activity.


Asunto(s)
Proteínas de Unión al GTP , Metiltransferasas , Procesamiento Postranscripcional del ARN , ARN de Transferencia , Humanos , Biocatálisis , Dominio Catalítico , Proteínas de Unión al GTP/química , Proteínas de Unión al GTP/metabolismo , Metiltransferasas/antagonistas & inhibidores , Metiltransferasas/química , Metiltransferasas/metabolismo , Fosforilación , ARN de Transferencia/química , ARN de Transferencia/metabolismo , Especificidad por Sustrato
14.
Haematologica ; 108(3): 705-716, 2023 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-36226495

RESUMEN

Mivavotinib (TAK-659) is an investigational type 1 tyrosine kinase inhibitor with dual activity against spleen tyrosine kinase (SYK) and FMS-like tyrosine kinase 3 (FLT3). We conducted a phase Ib study to investigate the safety, tolerability, and efficacy of mivavotinib in patients with refractory and/or relapsed (R/R) acute myeloid leukemia (AML). Both daily (QD) and twice daily (BID) dosing regimens were evaluated. A total of 43 patients were enrolled, and there were 5 complete responses (4 with incomplete count recovery). In the QD dosing regimen, the maximum tolerated dose (MTD) was not reached up to 160 mg QD per protocol; 140 mg QD was identified as the recommended phase II dose. In the BID dosing regimen, the MTD was 60 mg BID. Thirty patients (70%) experienced a bleeding event on study; the majority were grades 1 or 2, were resolved without mivavotinib modification, and were not considered related to study treatment. Eleven patients (26%) experienced grade ≥3 bleeding events, which were observed most frequently with the 80 mg BID dose. We conducted platelet aggregation studies to investigate the potential role of mivavotinib-mediated SYK inhibition on platelet function. The bleeding events observed may have been the result of several confounding factors, including AML disease status, associated thrombocytopenia, and high doses of mivavotinib. Overall, these findings indicate that the activity of mivavotinib in R/R AML is modest. Furthermore, any future clinical investigation of this agent should be undertaken with caution, particularly in thrombocytopenic patients, due to the potential bleeding risk of SYK inhibition. ClinicalTrials.gov: NCT02323113.


Asunto(s)
Leucemia Mieloide Aguda , Tirosina Quinasa 3 Similar a fms , Humanos , Inhibidores de Proteínas Quinasas/efectos adversos , Pirimidinas/efectos adversos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Quinasa Syk
15.
Nucleic Acids Res ; 51(D1): D248-D261, 2023 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-36440758

RESUMEN

Upstream open reading frames (uORFs) are typically defined as translation sites located within the 5' untranslated region upstream of the main protein coding sequence (CDS) of messenger RNAs (mRNAs). Although uORFs are prevalent in eukaryotic mRNAs and modulate the translation of downstream CDSs, a comprehensive resource for uORFs is currently lacking. We developed Ribo-uORF (http://rnainformatics.org.cn/RiboUORF) to serve as a comprehensive functional resource for uORF analysis based on ribosome profiling (Ribo-seq) data. Ribo-uORF currently supports six species: human, mouse, rat, zebrafish, fruit fly, and worm. Ribo-uORF includes 501 554 actively translated uORFs and 107 914 upstream translation initiation sites (uTIS), which were identified from 1495 Ribo-seq and 77 quantitative translation initiation sequencing (QTI-seq) datasets, respectively. We also developed mRNAbrowse to visualize items such as uORFs, cis-regulatory elements, genetic variations, eQTLs, GWAS-based associations, RNA modifications, and RNA editing. Ribo-uORF provides a very intuitive web interface for conveniently browsing, searching, and visualizing uORF data. Finally, uORFscan and UTR5var were developed in Ribo-uORF to precisely identify uORFs and analyze the influence of genetic mutations on uORFs using user-uploaded datasets. Ribo-uORF should greatly facilitate studies of uORFs and their roles in mRNA translation and posttranscriptional control of gene expression.


Asunto(s)
Sistemas de Lectura Abierta , Perfilado de Ribosomas , Animales , Humanos , Regiones no Traducidas 5' , Eucariontes/genética , Sistemas de Lectura Abierta/genética , Biosíntesis de Proteínas/genética , ARN Mensajero/genética , Biología Computacional/métodos
16.
Dent Mater J ; 42(2): 228-235, 2023 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-36464292

RESUMEN

Because nicotine upregulates the growth of most oral bacteria, this in vitro study investigated the antimicrobial effect of chlorhexidine-doped thin film on commercially pure titanium against Fusobacterium nucleatum (F. nucleatum) biofilm supplemented with different concentrations of nicotine (0, 1, and 2 mg/mL). Biofilms were formed on a chlorhexidine-doped thin film on commercially-pure-titanium discs and compared to the control groups. Biofilm viability, total biofilm growth using a spectrophotometer, extracellular polysaccharide content, and pH variations were assessed as dependent variables. Data were submitted to ANOVA and Tukey honest significant difference tests (α=0.05). F. nucleatum biofilm growth was inhibited when exposed to chlorhexidine-doped thin film (p<0.05). Biofilm supplemented with nicotine did not impact the synthesis of EPS on the same type of treatment (p>0.05). The pH values were significantly increased with the increase of nicotine concentration (p<0.05). Chlorhexidine-doped thin film was effective in reducing F. nucleatum biofilm supplemented with nicotine.


Asunto(s)
Antiinfecciosos , Clorhexidina , Clorhexidina/farmacología , Titanio/farmacología , Titanio/química , Nicotina/farmacología , Antiinfecciosos/farmacología , Biopelículas , Fusobacterium nucleatum
17.
Braz. j. oral sci ; 22: e231137, Jan.-Dec. 2023. ilus
Artículo en Inglés | LILACS, BBO | ID: biblio-1523140

RESUMEN

The purpose of this in vitro study was to analyze the influence of nicotine on the extracellular polysaccharides in Fusobacterium nucleatum biofilm. Methods: F. nucleatum (ATCC 10953) biofilms supplemented with different concentrations of nicotine (0, 0.5, 1, 2, 4, and 8 mg/mL) were grown in two different BHI broth conditions [no sucrose and 1% sucrose]. Extracellular polysaccharides assay, pH measurements, and a spectrophotometric assay were performed. Data were submitted for ANOVA and Tukey honestly significant difference analyses (HSD) tests (α =.05). Results: Extracellular polysaccharides synthesis was influenced by an interaction between nicotine concentrations and growth medium solution containing sucrose (P<.05). The pH values declined in the sucrose-exposed biofilm were greater than in the group exposed only to nicotine (P<.05). The biofilm exposed to sucrose and nicotine had a higher total biofilm growth (P<.05) than the nicotine-treated biofilm without sucrose. Conclusions: Regardless of sucrose exposure, biofilms exposed to different nicotine concentrations influenced the amount of extracellular polysaccharides


Asunto(s)
Humanos , Polisacáridos Bacterianos/síntesis química , Fusobacterium nucleatum/crecimiento & desarrollo , Biopelículas/crecimiento & desarrollo , Nicotina/farmacología , Enfermedades Periodontales/microbiología , Espectrofotometría , Sacarosa/administración & dosificación , Medios de Cultivo , Caries Dental/microbiología , Nicotina/administración & dosificación
18.
Nat Commun ; 13(1): 7904, 2022 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-36550132

RESUMEN

N6-methyladenosine (m6A), the most abundant modification of mRNA, is essential for normal development and dysregulation promotes cancer. m6A is highly enriched in the 3' untranslated region (UTR) of a large subset of mRNAs to influence mRNA stability and/or translation. However, the mechanism responsible for the observed m6A distribution remains enigmatic. Here we find the exon junction complex shapes the m6A landscape by blocking METTL3-mediated m6A modification close to exon junctions within coding sequence (CDS). Depletion of EIF4A3, a core component of the EJC, causes increased METTL3 binding and m6A modification of short internal exons, and sites close to exon-exon junctions within mRNA. Reporter gene experiments further support the role of splicing and EIF4A3 deposition in controlling m6A modification via the local steric blockade of METTL3. Our results explain how characteristic patterns of m6A mRNA modification are established and uncover a role of the EJC in shaping the m6A epitranscriptome.


Asunto(s)
Núcleo Celular , Empalme del ARN , Empalme del ARN/genética , Núcleo Celular/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Exones/genética , Estabilidad del ARN/genética
19.
J Med Chem ; 65(22): 15174-15207, 2022 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-36378954

RESUMEN

The bromodomain and extra terminal (BET) family of proteins are an integral part of human epigenome regulation, the dysregulation of which is implicated in multiple oncology and inflammatory diseases. Disrupting the BET family bromodomain acetyl-lysine (KAc) histone protein-protein interaction with small-molecule KAc mimetics has proven to be a disease-relevant mechanism of action, and multiple molecules are currently undergoing oncology clinical trials. This work describes an efficiency analysis of published GSK pan-BET bromodomain inhibitors, which drove a strategic choice to focus on the identification of a ligand-efficient KAc mimetic with the hypothesis that lipophilic efficiency could be drastically improved during optimization. This focus drove the discovery of the highly ligand-efficient and structurally distinct benzoazepinone KAc mimetic. Following crystallography to identify suitable growth vectors, the benzoazepinone core was optimized through an explore-exploit structure-activity relationship (SAR) approach while carefully monitoring lipophilic efficiency to deliver I-BET432 (41) as an oral candidate quality molecule.


Asunto(s)
Lisina , Factores de Transcripción , Humanos , Lisina/metabolismo , Ligandos , Dominios Proteicos , Histonas/metabolismo
20.
Xenobiotica ; 52(8): 928-942, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36227740

RESUMEN

Understanding compound metabolism in early drug discovery aids medicinal chemistry in designing molecules with improved safety and ADME properties. While advancements in metabolite prediction brings increased confidence, structural decisions require experimental data. In vitro metabolism studies using liquid chromatography and high-resolution mass spectrometry (LC-MS) are generally resource intensive and performed on very few compounds, limiting the chemical space that can be examined.Here, we describe a novel metabolism strategy increasing compound throughput using residual in vitro clearance samples conducted at drug concentrations of 0.5 µM. Analysis by robust ultra high-performance liquid chromatography separation and accurate-mass MS detection ensures major metabolites are identified from a single injection. In silico prediction (parent cLogD) tailors chromatographic conditions, with data-dependent tandem mass spectroscopy targeting predicted metabolites. Software-assisted data mining, structure elucidation and automatic reporting are used.Confidence in the globally aligned workflow is demonstrated with 16 marketed drugs. The approach is now implemented routinely across our laboratories. To date, the success rate for identification of at least one major metabolite is 85%. The utility of these data has been demonstrated across multiple projects, allowing earlier medicinal chemistry decisions to increase efficiency and impact of the design-make-test cycle thus improving the translatability of early in vitro metabolism data.


Asunto(s)
Programas Informáticos , Espectrometría de Masas en Tándem , Cromatografía Liquida/métodos , Cromatografía Líquida de Alta Presión , Espectrometría de Masas en Tándem/métodos , Biotransformación
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