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1.
J Lipid Res ; 65(9): 100621, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39151590

RESUMEN

The rapid increase in lipidomic studies has led to a collaborative effort within the community to establish standards and criteria for producing, documenting, and disseminating data. Creating a dynamic easy-to-use checklist that condenses key information about lipidomic experiments into common terminology will enhance the field's consistency, comparability, and repeatability. Here, we describe the structure and rationale of the established Lipidomics Minimal Reporting Checklist to increase transparency in lipidomics research.

2.
Virology ; 598: 110195, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39089050

RESUMEN

Rotavirus A is a leading cause of non-bacterial gastroenteritis in humans and domesticated animals. Despite the vast diversity of bovine Rotavirus A strains documented in South Asian countries, there are very few whole genomes available for phylogenetic study. A cross-sectional study identified a high prevalence of the G6P[11] genotype of bovine Rotavirus A circulating in the commercial cattle population in Bangladesh. Next-generation sequencing and downstream phylogenetic analysis unveiled all 11 complete gene segments of this strain (BD_ROTA_CVASU), classifying it under the genomic constellation G6P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3, which belongs to a classical DS-1-like genomic backbone. We found strong evidence of intragenic recombination between human and bovine strains in the Non-structural protein 4 (NSP4) gene, which encodes a multifunctional enterotoxin. Our analyses highlight frequent zoonotic transmissions of rotaviruses in diverse human-animal interfaces, which might have contributed to the evolution and pathogenesis of this dominant genotype circulating in the commercial cattle population in Bangladesh.


Asunto(s)
Enfermedades de los Bovinos , Genoma Viral , Genotipo , Filogenia , Recombinación Genética , Infecciones por Rotavirus , Rotavirus , Toxinas Biológicas , Proteínas no Estructurales Virales , Animales , Bovinos , Rotavirus/genética , Rotavirus/clasificación , Rotavirus/aislamiento & purificación , Bangladesh/epidemiología , Proteínas no Estructurales Virales/genética , Humanos , Infecciones por Rotavirus/virología , Infecciones por Rotavirus/veterinaria , Infecciones por Rotavirus/epidemiología , Enfermedades de los Bovinos/virología , Enfermedades de los Bovinos/epidemiología , Estudios Transversales , Toxinas Biológicas/genética , Glicoproteínas/genética
3.
Artículo en Inglés | MEDLINE | ID: mdl-39137242

RESUMEN

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can provide valuable insights into the metabolome of complex biological systems such as organ tissues and cells. However, obtaining metabolite data at single-cell spatial resolutions presents a few technological challenges. Generally, spatial resolution is defined by the increment the sample stage moves between laser ablation spots. Stage movements less than the diameter of the focused laser beam (i.e., oversampling) can improve spatial resolution; however, such oversampling conditions result in a reduction in sensitivity. To overcome this, we combine an oversampling approach with laser postionization (MALDI-2), which allows for both higher spatial resolution and improved analyte ionization efficiencies. This approach provides significant enhancements to sensitivity for various metabolite classes (e.g., amino acids, purines, carbohydrates etc.), with mass spectral intensities from 6 to 8 µm pixel sizes (from a laser spot size of ∼13 µm) being commensurate with or higher than those obtained by conventional MALDI at 20 µm pixel sizes for many different metabolites. This technique has been used to map the distribution of metabolites throughout mouse spinal cord tissue to observe how metabolite localizations change throughout specific anatomical regions, such as those distributed to the somatosensory area of the dorsal horn, white matter, gray matter, and ventral horn. Furthermore, this method is utilized for single-cell metabolomics of human iPSC-derived astrocytes at 10 µm pixel sizes whereby many different metabolites, including nucleotides, were detected from individual cells while providing insight into cellular localizations.

5.
PLoS One ; 19(8): e0308958, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39150925

RESUMEN

Maternal separation in early life has been observed to have lasting, detrimental effects that impair personal and social development and can persist into adulthood. Maternal separation during infancy can be most detrimental during adolescence, leading to long-term adverse effects on development and social behavior. This research study compared the effects of sibling and maternal separation in infancy on anxiety, sociability, or memory later in adolescence (postnatal day, PND, 50-58) in male and female Long-Evans Rats (Rattus norvegicus). Rat pups were semi-randomly assigned into eight conditions for daily isolation (PND 1-14). The groups were separated by the duration of isolation between 15 minutes (control group) or 180 minutes (experimental group) and the sex of the rat. They were also separated by comfort conditions with the dam present in an adjoining cage versus not present and siblings present or not present during isolation. The result was a 2 (15-min vs. 180-min) x 2 (dam vs. no dam) x 2 (single vs. grouped) x 2 (male vs. female) design. Once pups had reached adolescence (PND 50), researchers tested for differences in anxiety, activity, and social behavior using elevated plus-maze, open field habituation, a three-chamber social interaction, and a social discrimination task. Results indicate that longer isolation was more stressful and caused lower body weight. The female rats showed more anxious behavior in the open field but only if they were in the shorter isolation group. Social interaction showed that the rats isolated with the dam had different effects of isolation. In males, shorter isolation with the dam increased sociability but decreased sociability in females. These complicated findings may be due to the effects of inoculation, which describes how moderate stress combined with comfort may produce adaptation or immunity to stress and affect males and females differently.


Asunto(s)
Ansiedad , Conducta Animal , Privación Materna , Ratas Long-Evans , Hermanos , Conducta Social , Animales , Femenino , Masculino , Ratas , Conducta Animal/fisiología , Aislamiento Social/psicología , Memoria/fisiología
7.
Front Rehabil Sci ; 5: 1277509, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39011087

RESUMEN

Introduction: Many military service members and civilians suffer from lower extremity trauma. Despite recent advancements in lower limb bracing technology, it remains unclear whether these newer advanced braces offer improved comfort and functionality compared to conventional options. The IDEO (Intrepid Dynamic Exoskeletal Orthosis), a type of "advanced" orthosis was developed to assist in maintaining high functional performance in patients who have experienced high-energy lower extremity trauma and underwent limb salvage surgeries. Methods: A cross-sector multi-site initiative was completed to study the efficacy of advanced ankle foot orthoses (AFO) for lower limb trauma and injury compared to a conventional AFO. Following fitting, training, and accommodation, the subjects were assessed in each AFO system for mobility, self-reported function, safety and pain, and preference. Results: They preferred the advanced over the conventional AFO and the mobility and exertion perception improved with the advanced AFO with no difference in pain or overall health status scores. Discussion: Thus, an advanced AFO is an option for trauma affecting the lower limb. Long-term studies are required to better understand the accommodation and learning process of using an advanced AFO.

8.
Antioxidants (Basel) ; 13(7)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-39061857

RESUMEN

Coronary artery disease (CAD) and myocardial infarction (MI) remain leading causes of death and disability worldwide. CAD begins with the formation of atherosclerotic plaques within the intimal layer of the coronary arteries, a process driven by persistent arterial inflammation and oxidation. Myeloperoxidase (MPO), a mammalian haem peroxidase enzyme primarily expressed within neutrophils and monocytes, has been increasingly recognised as a key pro-inflammatory and oxidative enzyme promoting the development of vulnerable coronary atherosclerotic plaques that are prone to rupture, and can precipitate a MI. Mounting evidence also implicates a pathogenic role for MPO in the inflammatory process that follows a MI, which is characterised by the rapid infiltration of activated neutrophils into the damaged myocardium and the release of MPO. Excessive and persistent cardiac inflammation impairs normal cardiac healing post-MI, resulting in adverse cardiac outcomes and poorer long-term cardiac function, and eventually heart failure. This review summarises the evidence for MPO as a significant oxidative enzyme contributing to the inappropriate inflammatory responses driving the progression of CAD and poor cardiac healing after a MI. It also details the proposed mechanisms underlying MPO's pathogenic actions and explores MPO as a novel therapeutic target for the treatment of unstable CAD and cardiac damage post-MI.

9.
Res Sq ; 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38947076

RESUMEN

Background: The demand for genetic services has outpaced the availability of resources, challenging clinicians untrained in genetic integration into clinical decision-making. The UTHealth Adult Cardiovascular Genomics Certificate (CGC) program trains non-genetic healthcare professionals to recognize, assess, and refer patients with heritable cardiovascular diseases. This asynchronous online course includes 24 modules in three tiers of increasing complexity, using realistic clinical scenarios, interactive dialogues, quizzes, and tests to reinforce learning. We hypothesized that the CGC will increase genomic competencies in this underserved audience and encourage applying genomic concepts in clinical practice. Methods: Required course evaluations include pre- and post-assessments, knowledge checks in each module, and surveys for module-specific feedback. After 6 months, longitudinal feedback surveys gathered data on the long-term impact of the course on clinical practice and conducted focused interviews with learners. Results: The CGC was accredited in September 2022. Principal learners were nurses (24%), nurse practitioners (21%), physicians (16%), and physician assistants. Scores of 283 learners in paired pre- and post-assessments increased specific skills related to recognizing heritable diseases, understanding inheritance patterns, and interpreting genetic tests. Interviews highlighted the CGC's modular structure and linked resources as key strengths. Learners endorsed confidence to use genetic information in clinical practice, such as discussing genetic concepts and risks with patients and referring patients for genetic testing. Learners were highly likely to recommend the CGC to colleagues, citing its role in enhancing heritable disease awareness. Conclusions: The CGC program effectively empowers non-genetic clinicians to master genomic competencies, fostering collaboration to prevent deaths from heritable cardiovascular diseases, and potentially transforming healthcare education and clinical practice.

10.
Ecol Evol ; 14(7): e11598, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39055774

RESUMEN

Gape-limited predators (e.g., snakes, many fish) are not generally expected to pose a predation threat to prey that are too large for them to swallow. However, the extent to which snakes predate on prey that exceed their gape limitation remains largely unknown. We conducted the first study to investigate the influence of both prey and predator sizes on the frequency of ingestion success by snakes in a natural system. We combined survival monitoring of an avian prey species (Aplonis opaca) via radio-telemetry with a survey of the size distribution of their major predator (Boiga irregularis) on Guam. This allowed us to assess (1) the frequency of unsuccessful ingestion by the predator, (2) whether the size of the prey predicts ingestion success, (3) whether the size of the predator predicts ingestion success, and (4) the relationship between prey and predator sizes in successful ingestion attempts. We found that nearly half (47.95%) of ingestion attempts by snakes on fledgling birds were unsuccessful, and no instances where unsuccessful ingestion caused the mortality of the snake. Attempts to consume smaller fledglings were as likely to be unsuccessful as attempts to swallow larger fledglings. However, snakes that successfully ingested fledglings were among the largest snakes in the population, and larger than average conspecifics attracted to endothermic prey. The smallest snakes that successfully ingested fledglings attained remarkably high relative prey mass values for their species, consuming prey weighing up to 79.9% of their own mass. Our study indicates that B. irregularis routinely predate prey that are too large for them to successfully ingest, which causes mortality to the prey but poses little risk to the predator. The potential reward for snakes in consuming oversized prey may outweigh the inherent risks, while instances of predation that do not result in consumption may have considerable impacts on prey populations.

11.
Cancer Biol Ther ; 25(1): 2382524, 2024 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-39054566

RESUMEN

Thioredoxin Reductase (TrxR) functions to recycle thioredoxin (Trx) during hydroperoxide metabolism mediated by peroxiredoxins and is currently being targeted using the FDA-approved anti-rheumatic drug, auranofin (AF), to selectively sensitize cancer cells to therapy. AF treatment decreased TrxR activity and clonogenic survival in small cell lung cancer (SCLC) cell lines (DMS273 and DMS53) as well as the H727 atypical lung carcinoid cell line. AF treatment also significantly sensitized DMS273 and H727 cell lines in vitro to sorafenib, an FDA-approved multi-kinase inhibitor that depleted intracellular glutathione (GSH). The pharmacokinetic, pharmacodynamic, and safety profile of AF was examined in nude mice with DMS273 xenografts administered AF intraperitoneally at 2 mg/kg or 4 mg/kg (IP) once (QD) or twice daily (BID) for 1-5 d. Plasma levels of AF were 10-20 µM (determined by mass spectrometry of gold), and the optimal inhibition of TrxR activity was obtained at 4 mg/kg once daily, with no effect on glutathione peroxidase 1 activity. This AF treatment extended for 14 d, inhibited TrxR (>75%), and resulted in a significant prolongation of median overall survival from 19 to 23 d (p = .04, N = 30 controls, 28 AF). In this experiment, there were no observed changes in animal bodyweight, complete blood counts (CBCs), bone marrow toxicity, blood urea nitrogen, or creatinine. These results support the hypothesis that AF effectively inhibits TrxR both in vitro and in vivo in SCLC, sensitizes NETs and SCLC to sorafenib, and could be repurposed as an adjuvant therapy with targeted agents that induce disruptions in thiol metabolism.


Asunto(s)
Auranofina , Neoplasias Pulmonares , Compuestos de Fenilurea , Carcinoma Pulmonar de Células Pequeñas , Sorafenib , Reductasa de Tiorredoxina-Disulfuro , Ensayos Antitumor por Modelo de Xenoinjerto , Auranofina/farmacología , Auranofina/uso terapéutico , Animales , Sorafenib/farmacología , Sorafenib/uso terapéutico , Reductasa de Tiorredoxina-Disulfuro/antagonistas & inhibidores , Reductasa de Tiorredoxina-Disulfuro/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Carcinoma Pulmonar de Células Pequeñas/tratamiento farmacológico , Carcinoma Pulmonar de Células Pequeñas/patología , Carcinoma Pulmonar de Células Pequeñas/metabolismo , Humanos , Ratones , Línea Celular Tumoral , Compuestos de Fenilurea/farmacología , Compuestos de Fenilurea/uso terapéutico , Tumores Neuroendocrinos/tratamiento farmacológico , Tumores Neuroendocrinos/patología , Tumores Neuroendocrinos/metabolismo , Ratones Desnudos , Niacinamida/análogos & derivados , Niacinamida/farmacología , Niacinamida/uso terapéutico , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico
12.
Virology ; 598: 110173, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39018684

RESUMEN

Wild birds harbour a vast diversity of adenoviruses that remain uncharacterised with respect to their genome organisation and evolutionary relatedness within complex host ecosystems. Here, we characterise a novel adenovirus type within Aviadenovirus genus associated with severe necrotising hepatitis in a captive Timneh grey parrot, tentatively named as Timneh grey parrot adenovirus 1 (TpAdV-1). The TpAdV-1 genome is 39,867 bp and encodes 46 putative genes with seven hitherto not described ones. Comparative genomics and phylogenetic analyses revealed highest nucleotide identity with psittacine adenovirus 1 and psittacine adenovirus 4 that formed a discrete monophyletic clade within Aviadenovirus lineage suggesting a deep host co-divergent lineage within Psittaciformes hosts. Several recombination breakpoints were identified within the TpAdV-1 genome, which highlighted an ancient evolutionary relationship across the genera Aviadenovirus, Mastadenovirus and Atadenovirus. This study hints towards a host-adapted sub-lineage of avian adenovirus capable of having significant host virulence in Psittaciformes birds augmented with ecological opportunity.


Asunto(s)
Infecciones por Adenoviridae , Aviadenovirus , Enfermedades de las Aves , Genoma Viral , Loros , Filogenia , Animales , Infecciones por Adenoviridae/veterinaria , Infecciones por Adenoviridae/virología , Aviadenovirus/genética , Aviadenovirus/clasificación , Aviadenovirus/aislamiento & purificación , Aviadenovirus/patogenicidad , Loros/virología , Enfermedades de las Aves/virología
13.
Clin Ophthalmol ; 18: 1525-1534, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38827771

RESUMEN

Purpose: To evaluate dry eye disease (DED) signs and symptoms six months after a single treatment with Localized Heat Therapy (LHT) (TearCare, Sight Sciences) for patients previously treated for six months with cyclosporine (0.05%) ophthalmic emulsion (CsA) BID (Restasis, Allergan). Setting: Nineteen ophthalmic and optometric practices in 11 US states. Design: Multicenter, cross-over, six month extension to the SAHARA randomized, controlled trial (RCT). Included patients were those randomized to CsA in Phase 1 of the SAHARA RCT. Methods: This was the second phase of the SAHARA RCT in which, following the 6-month endpoint, all patients that had been randomized to CsA discontinued CsA and were treated with LHT and subsequently followed for an additional six months. Outcome measures at 12 months for CsA patients crossed over to LHT included TBUT, OSDI and MGSS. Results: One hundred and sixty-one patients (322 eyes) were analyzed. Mean (SD) baseline TBUT prior to CsA was 4.4 (1.2) seconds, 5.6 (2.6) at 6 months which improved to 6.6 (3.2) and 6.1 (2.8) seconds (both P < 0.001) at 9 and 12 months (3, 6 months post LHT). Mean (SD) OSDI was 50.0 (14.9) at baseline and 34.2 (21.5) after CsA. With LHT at 6 months, this improved to 30.0 (20.6) and 31.0 (19.5) at 9 and 12 months (P = 0.162 vs month 6, P < 0.0001 vs baseline). MGSS was 7.1 (3.2) at baseline, 13.3 (8.2) at the end of CsA treatment which improved to 17.4 (8.8) and 16.1 (9.0) at 9 and 12 months; both P <0.001. Conclusion: SAHARA showed 6-month superiority of LHT to CsA in clinical signs and non-inferiority in symptom scores. This extension shows that patients treated with CsA for 6 months can achieve meaningful additional improvement in signs and symptoms lasting for as long as 6 months following a single LHT treatment without the need for topical prescription therapy.

14.
bioRxiv ; 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38854053

RESUMEN

Background: Epigenetic regulation of gene expression and host defense is well established in microbial communities, with dozens of DNA modifications comprising the epigenomes of prokaryotes and bacteriophage. Phosphorothioation (PT) of DNA, in which a chemically-reactive sulfur atom replaces a non-bridging oxygen in the sugar-phosphate backbone, is catalyzed by dnd and ssp gene families widespread in bacteria and archaea. However, little is known about the role of PTs or other microbial epigenetic modifications in the human microbiome. Here we optimized and applied fecal DNA extraction, mass spectrometric, and metagenomics technologies to characterize the landscape and temporal dynamics of gut microbes possessing PT modifications. Results: Exploiting the nuclease-resistance of PTs, mass spectrometric analysis of limit digests of PT-containing DNA reveals PT dinucleotides as part of genomic consensus sequences, with 16 possible dinucleotide combinations. Analysis of mouse fecal DNA revealed a highly uniform spectrum of 11 PT dinucleotides in all littermates, with PTs estimated to occur in 5-10% of gut microbes. Though at similar levels, PT dinucleotides in fecal DNA from 11 healthy humans possessed signature combinations and levels of individual PTs. Comparison with a widely distributed microbial epigenetic mark, m6dA, suggested temporal dynamics consistent with expectations for gut microbial communities based on Taylor's Power Law. Application of PT-seq for site-specific metagenomic analysis of PT-containing bacteria in one fecal donor revealed the larger consensus sequences for the PT dinucleotides in Bacteroidota, Firmicutes, Actinobacteria, and Proteobacteria, which differed from unbiased metagenomics and suggested that the abundance of PT-containing bacteria did not simply mirror the spectrum of gut bacteria. PT-seq further revealed low abundance PT sites not detected as dinucleotides by mass spectrometry, attesting to the complementarity of the technologies. Conclusions: The results of our studies provide a benchmark for understanding the behavior of an abundant and chemically-reactive epigenetic mark in the human gut microbiome, with implications for inflammatory conditions of the gut.

15.
bioRxiv ; 2024 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-38826421

RESUMEN

Monogenic syndromes are associated with neurodevelopmental changes that result in cognitive impairments, neurobehavioral phenotypes including autism and attention deficit hyperactivity disorder (ADHD), and seizures. Limited studies and resources are available to make meaningful headway into the underlying molecular mechanisms that result in these symptoms. One such example is DeSanto-Shinawi Syndrome (DESSH), a rare disorder caused by pathogenic variants in the WAC gene. Individuals with DESSH syndrome exhibit a recognizable craniofacial gestalt, developmental delay/intellectual disability, neurobehavioral symptoms that include autism, ADHD, behavioral difficulties and seizures. However, no thorough studies from a vertebrate model exist to understand how these changes occur. To overcome this, we developed both murine and zebrafish Wac/wac deletion mutants and studied whether their phenotypes recapitulate those described in individuals with DESSH syndrome. We show that the two Wac models exhibit craniofacial and behavioral changes, reminiscent of abnormalities found in DESSH syndrome. In addition, each model revealed impacts to GABAergic neurons and further studies showed that the mouse mutants are susceptible to seizures, changes in brain volumes that are different between sexes and relevant behaviors. Finally, we uncovered transcriptional impacts of Wac loss of function that will pave the way for future molecular studies into DESSH. These studies begin to uncover some biological underpinnings of DESSH syndrome and elucidate the biology of Wac, with advantages in each model.

16.
bioRxiv ; 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38895356

RESUMEN

Among dozens of microbial DNA modifications regulating gene expression and host defense, phosphorothioation (PT) is the only known backbone modification, with sulfur inserted at a non-bridging oxygen by dnd and ssp gene families. Here we explored the distribution of PT genes in 13,663 human gut microbiome genomes, finding that 6.3% possessed dnd or ssp genes predominantly in Bacillota, Bacteroidota, and Pseudomonadota. This analysis uncovered several putative new PT synthesis systems, including Type 4 Bacteriophage Exclusion (BREX) brx genes, which were genetically validated in Bacteroides salyersiae. Mass spectrometric analysis of DNA from 226 gut microbiome isolates possessing dnd, ssp, and brx genes revealed 8 PT dinucleotide settings confirmed in 6 consensus sequences by PT-specific DNA sequencing. Genomic analysis showed PT enrichment in rRNA genes and depletion at gene boundaries. These results illustrate the power of the microbiome for discovering prokaryotic epigenetics and the widespread distribution of oxidation-sensitive PTs in gut microbes.

17.
bioRxiv ; 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38895297

RESUMEN

Among dozens of known epigenetic marks, naturally occurring phosphorothioate (PT) DNA modifications are unique in replacing a non-bridging phosphate oxygen with redox-active sulfur and function in prokaryotic restriction-modification and transcriptional regulation. Interest in PTs has grown due to the widespread distribution of the dnd, ssp, and brx genes among bacteria and archaea, as well as the discovery of PTs in 5-10% of gut microbes. Efforts to map PTs in complex microbiomes using existing next-generation and direct sequencing technologies have failed due to poor sensitivity. Here we developed PT-seq as a high-sensitivity method to quantitatively map PTs across genomes and metagenomically identify PT-containing microbes in complex genomic mixtures. Like other methods for mapping PTs in individual genomes, PT-seq exploits targeted DNA strand cleavage at PTs by iodine, followed by sequencing library construction using ligation or template switching approaches. However, PT-specific sequencing reads are dramatically increased by adding steps to heat denature the DNA, block pre-existing 3'-ends, fragment DNA after T-tailing, and enrich iodine-induced breaks using biotin-labeling and streptavidin beads capture. Iterative optimization of the sensitivity and specificity of PT-seq is demonstrated with individual bacteria and human fecal DNA.

18.
J Phys Chem Lett ; 15(24): 6325-6333, 2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38856977

RESUMEN

Accurate simulation models for water interactions with graphene and graphite are important for nanofluidic applications, but existing force fields produce widely varying contact angles. Our extensive review of the experimental literature reveals extreme variation among reported values of graphene-water contact angles and a clustering of graphite-water contact angles into groups of freshly exfoliated (60° ± 13°) and not-freshly exfoliated graphite surfaces. The carbon-oxygen dispersion energy for a classical force field is optimized with respect to this 60° graphite-water contact angle in the infinite-force-cutoff limit, which in turn yields a contact angle for unsupported graphene of 80°, in agreement with the mean of the experimental results. Interaction force fields for finite cutoffs are also derived. A method for calculating contact angles from pressure tensors of planar equilibrium simulations that is ideally suited to graphite and graphene surfaces is introduced. Our methodology is widely applicable to any liquid-surface combination.

19.
Plant Cell Environ ; 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38932650

RESUMEN

Aquatic ferns of the genus Azolla (Azolla) form highly productive symbioses with filamentous cyanobacteria fixing N2 in their leaf cavities, Nostoc azollae. Stressed symbioses characteristically turn red due to 3-deoxyanthocyanidin (DA) accumulation, rare in angiosperms and of unknown function. To understand DA accumulation upon cold acclimation and recovery, we integrated laser-desorption-ionization mass-spectrometry-imaging (LDI-MSI), a new Azolla filiculoides genome-assembly and annotation, and dual RNA-sequencing into phenotypic analyses of the symbioses. Azolla sp. Anzali recovered even when cold-induced DA-accumulation was inhibited by abscisic acid. Cyanobacterial filaments generally disappeared upon cold acclimation and Nostoc azollae transcript profiles were unlike those of resting stages formed in cold-resistant sporocarps, yet filaments re-appeared in leaf cavities of newly formed green fronds upon cold-recovery. The high transcript accumulation upon cold acclimation of AfDFR1 encoding a flavanone 4-reductase active in vitro suggested that the enzyme of the first step in the DA-pathway may regulate accumulation of DAs in different tissues. However, LDI-MSI highlighted the necessity to describe metabolite accumulation beyond class assignments as individual DA and caffeoylquinic acid metabolites accumulated differentially. For example, luteolinidin accumulated in epithelial cells, including those lining the leaf cavity, supporting a role for the former in the symbiotic interaction during cold acclimation.

20.
ACS Synth Biol ; 13(7): 1964-1977, 2024 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-38885464

RESUMEN

Bacteriophage RNA polymerases, in particular T7 RNA polymerase (RNAP), are well-characterized and popular enzymes for many RNA applications in biotechnology both in vitro and in cellular settings. These monomeric polymerases are relatively inexpensive and have high transcription rates and processivity to quickly produce large quantities of RNA. T7 RNAP also has high promoter-specificity on double-stranded DNA (dsDNA) such that it only initiates transcription downstream of its 17-base promoter site on dsDNA templates. However, there are many promoter-independent T7 RNAP transcription reactions involving transcription initiation in regions of single-stranded DNA (ssDNA) that have been reported and characterized. These promoter-independent transcription reactions are important to consider when using T7 RNAP transcriptional systems for DNA nanotechnology and DNA computing applications, in which ssDNA domains often stabilize, organize, and functionalize DNA nanostructures and facilitate strand displacement reactions. Here we review the existing literature on promoter-independent transcription by bacteriophage RNA polymerases with a specific focus on T7 RNAP, and provide examples of how promoter-independent reactions can disrupt the functionality of DNA strand displacement circuit components and alter the stability and functionality of DNA-based materials. We then highlight design strategies for DNA nanotechnology applications that can mitigate the effects of promoter-independent T7 RNAP transcription. The design strategies we present should have an immediate impact by increasing the rate of success of using T7 RNAP for applications in DNA nanotechnology and DNA computing.


Asunto(s)
ARN Polimerasas Dirigidas por ADN , ADN , Nanoestructuras , Regiones Promotoras Genéticas , Transcripción Genética , Proteínas Virales , ARN Polimerasas Dirigidas por ADN/metabolismo , ARN Polimerasas Dirigidas por ADN/genética , Proteínas Virales/metabolismo , Proteínas Virales/genética , Nanoestructuras/química , ADN/metabolismo , ADN/genética , ADN/química , ADN de Cadena Simple/genética , ADN de Cadena Simple/metabolismo , ADN de Cadena Simple/química , Nanotecnología/métodos , Bacteriófago T7/genética
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