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1.
BMC Public Health ; 24(1): 1713, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38926697

RESUMO

BACKGROUND: While many populations struggle with health literacy, those who speak Spanish preferentially or exclusively, including Hispanic, immigrant, or migrant populations, may face particular barriers, as they navigate a predominantly English-language healthcare system. This population also faces greater morbidity and mortality from treatable chronic diseases, such as hypertension and diabetes. The aim of this systematic review was to describe existing health literacy interventions for patients with a Spanish-language preference and present their effectiveness. METHODS: We carried out a systematic review where Web of Science, EMBASE, and PubMed were queried using MeSH terms to identify relevant literature. Included articles described patients with a Spanish-language preference participating in interventions to improve health literacy levels in the United States. Screening and data abstraction were conducted independently and in pairs. Risk of bias assessments were conducted using validated appraisal tools. RESULTS: A total of 2823 studies were identified, of which 62 met our eligibility criteria. The studies took place in a variety of community and clinical settings and used varied tools for measuring health literacy. Of the interventions, 28 consisted of in-person education and 27 implemented multimedia education, with 89% of studies in each category finding significant results. The remaining seven studies featured multimodal interventions, all of which achieved significant results. CONCLUSION: Successful strategies included the addition of liaison roles, such as promotores (Hispanic community health workers), and the use of multimedia fotonovelas (photo comics) with linguistic and cultural adaptations. In some cases, the external validity of the results was limited. Improving low health literacy in patients with a Spanish-language preference, a population with existing barriers to high quality of care, may help them better navigate health infrastructure and make informed decisions regarding their health. REGISTRATION: PROSPERO (available at https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021257655.t ).


Assuntos
Letramento em Saúde , Hispânico ou Latino , Humanos , Estados Unidos , Hispânico ou Latino/estatística & dados numéricos , Hispânico ou Latino/psicologia , Idioma
2.
Nurs Inq ; : e12630, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38436620

RESUMO

Against the backdrop of cultural and political ideals, this article highlights both the significance of mental health nursing in meeting population needs and the regulatory barriers that may be impeding its ability to adequately do so. Specifically, we consider how ambiguous notions of 'proficiency' in nurse education-prescribed by the regulator-impact the development of future mental health nurses and their mental health nursing identity. A key tension in mental health practice is the ethical-legal challenges posed by sanctioned powers to restrict patients' freedom at the same time as the desire (and obligation) to promote patients' self-determined recovery. The genericism of the UK's Future Nurse Standards do little to prepare mental health nurses to navigate the tensions that ensue. This has consequences for nurses and patients alike, as both risk experiencing the distress and dissonance that attends giving or receiving poor care. We argue that more needs to be done to enable mental health nurses to define and articulate the nuances of the profession as part of becoming critical, thoughtful and confident practitioners. Educators can contribute to this mission by aligning curriculum, pedagogy and assessment to create meaningful opportunities for mental health nursing students to engage with the complexities of mental health nursing practice. Without this, the credibility of the profession will continue to be questioned; its future uncertain.

3.
Clin Transplant ; 36(9): e14754, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35771088

RESUMO

BACKGROUND: Due to the mechanisms of action of conventional catecholamine vasopressors, there is increased risk of renal allograft injury and adverse events in transplant recipients with fluid-refractory distributive shock during the perioperative period. As such, mechanistically alternative vasopressors like angiotensin II (ATII) may avoid these complications, but there is an absence of data supporting use in this population. METHODS: This was a single-center, single-arm, open-label, phase 4 study conducted as a 1-year pilot of 20 adult renal transplant recipients receiving ATII as their first continuous infusion vasopressor in the perioperative period. The study aim was to systematically assess the safety and hemodynamic effects of ATII. Safety was assessed based on the incidence of adverse events. Hemodynamic effect was assessed by the achievement of per protocol hemodynamic goals (i.e., SBP ≥120 mmHg) and the need for adjunct vasopressors. RESULTS: Most cases involved deceased donors (70%), with a corresponding mean (SD) cold ischemia time of 14.7 (8.6) h. Over a surgery duration of 5.3 (1.2) h, subjects received 3.2 (2.0) L of total volume resuscitation prior to ATII initiation. No adverse events were directly related to ATII administration. Throughout this period, ATII was utilized for a median of 1.0 (IQR, 1.5) h intraoperatively (N = 7), 26.5 (IQR, 84.8) h postoperatively (N = 4), and 63.8 (IQR, 57.8) h in subjects who required ATII both intra- and postoperatively (N = 9). Only one of the 20 patients needed adjunct continuous infusion vasopressors in addition to ATII. CONCLUSIONS: Based on the observations of this pilot study, ATII is a safe and effective vasopressor option for renal transplant recipients requiring perioperative hypotension reversal.


Assuntos
Hipotensão , Transplante de Rim , Adulto , Angiotensina II/farmacologia , Catecolaminas , Humanos , Hipotensão/tratamento farmacológico , Hipotensão/epidemiologia , Hipotensão/etiologia , Transplante de Rim/efeitos adversos , Projetos Piloto , Transplantados , Vasoconstritores/uso terapêutico
4.
Molecules ; 27(14)2022 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-35889292

RESUMO

The plant-derived macrocyclic resin glycoside ipomoeassin F (Ipom-F) binds to Sec61α and significantly disrupts multiple aspects of Sec61-mediated protein biogenesis at the endoplasmic reticulum, ultimately leading to cell death. However, extensive assessment of Ipom-F as a molecular tool and a therapeutic lead is hampered by its limited production scale, largely caused by intramolecular assembly of the macrocyclic ring. Here, using in vitro and/or in cellula biological assays to explore the first series of ring-opened analogues for the ipomoeassins, and indeed all resin glycosides, we provide clear evidence that macrocyclic integrity is not required for the cytotoxic inhibition of Sec61-dependent protein translocation by Ipom-F. Furthermore, our modeling suggests that open-chain analogues of Ipom-F can interact with multiple sites on the Sec61α subunit, most likely located at a previously identified binding site for mycolactone and/or the so-called lateral gate. Subsequent in silico-aided design led to the discovery of the stereochemically simplified analogue 3 as a potent, alternative lead compound that could be synthesized much more efficiently than Ipom-F and will accelerate future ipomoeassin research in chemical biology and drug discovery. Our work may also inspire further exploration of ring-opened analogues of other resin glycosides.


Assuntos
Antineoplásicos , Glicoconjugados , Antineoplásicos/química , Glicoconjugados/química , Glicosídeos/farmacologia , Canais de Translocação SEC/metabolismo
5.
BMC Nephrol ; 22(1): 45, 2021 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-33516188

RESUMO

BACKGROUND: To evaluate the transmembrane clearance (CLTM) of apixaban during modeled in vitro continuous renal replacement therapy (CRRT), assess protein binding and circuit adsorption, and provide initial dosing recommendations. METHODS: Apixaban was added to the CRRT circuit and serial pre-filter bovine blood samples were collected along with post-filter blood and effluent samples. All experiments were performed in duplicate using continuous veno-venous hemofiltration (CVVH) and hemodialysis (CVVHD) modes, with varying filter types, flow rates, and point of CVVH replacement fluid dilution. Concentrations of apixaban and urea were quantified via liquid chromatography-tandem mass spectrometry. Plasma pharmacokinetic parameters for apixaban were estimated via noncompartmental analysis. CLTM was calculated via the estimated area under the curve (AUC) and by the product of the sieving/saturation coefficient (SC/SA) and flow rate. Two and three-way analysis of variance (ANOVA) models were built to assess the effects of mode, filter type, flow rate, and point of dilution on CLTM by each method. Optimal doses were suggested by matching the AUC observed in vitro to the systemic exposure demonstrated in Phase 2/3 studies of apixaban. Linear regression was utilized to provide dosing estimations for flow rates from 0.5-5 L/h. RESULTS: Mean adsorption to the HF1400 and M150 filters differed significantly at 38 and 13%, respectively, while mean (± standard deviation, SD) percent protein binding was 70.81 ± 0.01%. Effect of CVVH point of dilution did not differ across filter types, although CLTM was consistently significantly higher during CRRT with the HF1400 filter compared to the M150. The three-way ANOVA demonstrated improved fit when CLTM values calculated by AUC were used (adjusted R2 0.87 vs. 0.52), and therefore, these values were used to generate optimal dosing recommendations. Linear regression revealed significant effects of filter type and flow rate on CLTM by AUC, suggesting doses of 2.5-7.5 mg twice daily (BID) may be needed for flow rates ranging from 0.5-5 L/h, respectively. CONCLUSION: For CRRT flow rates most commonly employed in clinical practice, the standard labeled 5 mg BID dose of apixaban is predicted to achieve target systemic exposure thresholds. The safety and efficacy of these proposed dosing regimens warrants further investigation in clinical studies.


Assuntos
Terapia de Substituição Renal Contínua , Inibidores do Fator Xa/farmacocinética , Pirazóis/farmacocinética , Piridonas/farmacocinética , Diálise Renal , Animais , Bovinos
6.
J Org Chem ; 85(24): 16226-16235, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33264019

RESUMO

Two new ring-size-varying analogues (2 and 3) of ipomoeassin F were synthesized and evaluated. Improved cytotoxicity (IC50: from 1.8 nM) and in vitro protein translocation inhibition (IC50: 35 nM) derived from ring expansion imply that the binding pocket of Sec61α (isoform 1) can accommodate further structural modifications, likely in the fatty acid portion. Streamlined preparation of the key diol intermediate 5 enabled gram-scale production, allowing us to establish that ipomoeassin F is biologically active in vivo (MTD: ∼3 mg/kg).


Assuntos
Glicoconjugados , Ensaios de Seleção de Medicamentos Antitumorais , Estrutura Molecular , Relação Estrutura-Atividade
7.
Nature ; 565(7737): 31-32, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30602742
8.
Nature ; 514(7520): 80-3, 2014 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-25279921

RESUMO

Seasonal acceleration of the Greenland Ice Sheet is influenced by the dynamic response of the subglacial hydrologic system to variability in meltwater delivery to the bed via crevasses and moulins (vertical conduits connecting supraglacial water to the bed of the ice sheet). As the melt season progresses, the subglacial hydrologic system drains supraglacial meltwater more efficiently, decreasing basal water pressure and moderating the ice velocity response to surface melting. However, limited direct observations of subglacial water pressure mean that the spatiotemporal evolution of the subglacial hydrologic system remains poorly understood. Here we show that ice velocity is well correlated with moulin hydraulic head but is out of phase with that of nearby (0.3-2 kilometres away) boreholes, indicating that moulins connect to an efficient, channelized component of the subglacial hydrologic system, which exerts the primary control on diurnal and multi-day changes in ice velocity. Our simultaneous measurements of moulin and borehole hydraulic head and ice velocity in the Paakitsoq region of western Greenland show that decreasing trends in ice velocity during the latter part of the melt season cannot be explained by changes in the ability of moulin-connected channels to convey supraglacial melt. Instead, these observations suggest that decreasing late-season ice velocity may be caused by changes in connectivity in unchannelized regions of the subglacial hydrologic system. Understanding this spatiotemporal variability in subglacial pressures is increasingly important because melt-season dynamics affect ice velocity beyond the conclusion of the melt season.

9.
J Neuroinflammation ; 15(1): 55, 2018 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-29471880

RESUMO

BACKGROUND: The cystine/glutamate antiporter (xc-) has been implicated in several neurological disorders and, specifically, in multiple sclerosis (MS) as a mediator of glutamate excitotoxicity and proinflammatory immune responses. We aimed to evaluate an xc-specific positron emission tomography (PET) radiotracer, (4S)-4-(3-[18F]fluoropropyl)-L-glutamate ([18F]FSPG), for its ability to allow non-invasive monitoring of xc- activity in a mouse model of MS. METHODS: Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice by subcutaneous injection of myelin oligodendrocyte glycoprotein (MOG35-55) peptide in complete Freund's adjuvant (CFA) followed by pertussis toxin. Control mice received CFA emulsion and pertussis toxin without MOG peptide, while a separate cohort of naïve mice received no treatment. PET studies were performed to investigate the kinetics and distribution of [18F]FSPG in naïve, control, pre-symptomatic, and symptomatic EAE mice, compared to 18F-fluorodeoxyglucose ([18F]FDG). After final PET scans, each mouse was perfused and radioactivity in dissected tissues was measured using a gamma counter. Central nervous system (CNS) tissues were further analyzed using ex vivo autoradiography or western blot. [18F]FSPG uptake in human monocytes, and T cells pre- and post-activation was investigated in vitro. RESULTS: [18F]FSPG was found to be more sensitive than [18F]FDG at detecting pathological changes in the spinal cord and brain of EAE mice. Even before clinical signs of disease, a small but significant increase in [18F]FSPG signal was observed in the spinal cord of EAE mice compared to controls. This increase in PET signal became more pronounced in symptomatic EAE mice and was confirmed by ex vivo biodistribution and autoradiography. Likewise, in the brain of symptomatic EAE mice, [18F]FSPG uptake was significantly higher than controls, with the largest changes observed in the cerebellum. Western blot analyses of CNS tissues revealed a significant correlation between light chain of xc- (xCT) protein levels, the subunit of xc- credited with its transporter activity, and [18F]FSPG-PET signal. In vitro [18F]FSPG uptake studies suggest that both activated monocytes and T cells contribute to the observed in vivo PET signal. CONCLUSION: These data highlight the promise of [18F]FSPG-PET as a technique to provide insights into neuroimmune interactions in MS and the in vivo role of xc- in the development and progression of this disease, thus warranting further investigation.


Assuntos
Sistemas de Transporte de Aminoácidos Acídicos/metabolismo , Encefalomielite Autoimune Experimental/diagnóstico por imagem , Encefalomielite Autoimune Experimental/metabolismo , Radioisótopos de Flúor/metabolismo , Glutamatos/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Animais , Células Cultivadas , Fluordesoxiglucose F18/metabolismo , Humanos , Leucócitos Mononucleares/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/metabolismo
11.
ACS Synth Biol ; 13(1): 282-299, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38079538

RESUMO

A universal biochemical signal for bacterial cell-cell communication could facilitate programming dynamic responses in diverse bacterial consortia. However, the classical quorum sensing paradigm is that Gram-negative and Gram-positive bacteria generally communicate via homoserine lactones (HSLs) or oligopeptide molecular signals, respectively, to elicit population responses. Here, we create synthetic HSL sensors for Gram-positive Bacillus subtilis 168 using allosteric LuxR-type regulators (RpaR, LuxR, RhlR, and CinR) and synthetic promoters. Promoters were combinatorially designed from different sequence elements (-35, -16, -10, and transcriptional start regions). We quantified the effects of these combinatorial promoters on sensor activity and determined how regulator expression affects its activation, achieving up to 293-fold activation. Using the statistical design of experiments, we identified significant effects of promoter regions and pairwise interactions on sensor activity, which helped to understand the sequence-function relationships for synthetic promoter design. We present the first known set of functional HSL sensors (≥20-fold dynamic range) in B. subtilis for four different HSL chemical signals: p-coumaroyl-HSL, 3-oxohexanoyl-HSL, n-butyryl-HSL, and n-(3-hydroxytetradecanoyl)-HSL. This set of synthetic HSL sensors for a Gram-positive bacterium can pave the way for designable interspecies communication within microbial consortia.


Assuntos
Proteínas Repressoras , Transativadores , Transativadores/genética , Transativadores/metabolismo , Proteínas Repressoras/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , 4-Butirolactona/metabolismo , Percepção de Quorum/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Homosserina/metabolismo
12.
ACS Synth Biol ; 13(1): 103-118, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38064657

RESUMO

Staphylococcus aureus is an important clinical bacterium prevalent in human-associated microbiomes and the cause of many diseases. However, S. aureus has been intractable to synthetic biology approaches due to limited characterized genetic parts for this nonmodel Gram-positive bacterium. Moreover, genetic manipulation of S. aureus has relied on cumbersome and inefficient cloning strategies. Here, we report the first standardized genetic parts toolbox for S. aureus, which includes characterized promoters, ribosome binding sites, terminators, and plasmid replicons from a variety of bacteria for precise control of gene expression. We established a standard relative expression unit (REU) for S. aureus using a plasmid reference and characterized genetic parts in standardized REUs using S. aureus ATCC 12600. We constructed promoter and terminator part plasmids that are compatible with an efficient Type IIS DNA assembly strategy to effectively build multipart DNA constructs. A library of 24 constitutive promoters was built and characterized in S. aureus, which showed a 380-fold activity range. This promoter library was also assayed in Bacillus subtilis (122-fold activity range) to demonstrate the transferability of the constitutive promoters between these Gram-positive bacteria. By applying an iterative design-build-test-learn cycle, we demonstrated the use of our toolbox for the rational design and engineering of a tetracycline sensor in S. aureus using the PXyl-TetO aTc-inducible promoter that achieved 25.8-fold induction. This toolbox greatly expands the growing number of genetic parts for Gram-positive bacteria and will allow researchers to leverage synthetic biology approaches to study and engineer cellular processes in S. aureus.


Assuntos
DNA , Staphylococcus aureus , Humanos , Staphylococcus aureus/genética , Plasmídeos/genética , Regiões Promotoras Genéticas/genética , Biblioteca Gênica
13.
ACS Synth Biol ; 13(2): 568-589, 2024 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-38206199

RESUMO

Programmable intercellular signaling using components of naturally occurring quorum sensing can allow for coordinated functions to be engineered in microbial consortia. LuxR-type transcriptional regulators are widely used for this purpose and are activated by homoserine lactone (HSL) signals. However, they often suffer from imperfect molecular discrimination of structurally similar HSLs, causing misregulation within engineered consortia containing multiple HSL signals. Here, we studied one such example, the regulator LasR from Pseudomonas aeruginosa. We elucidated its sequence-function relationship for ligand specificity using targeted protein engineering and multiplexed high-throughput biosensor screening. A pooled combinatorial saturation mutagenesis library (9,486 LasR DNA sequences) was created by mutating six residues in LasR's ß5 sheet with single, double, or triple amino acid substitutions. Sort-seq assays were performed in parallel using cognate and noncognate HSLs to quantify each corresponding sensor's response to each HSL signal, which identified hundreds of highly specific variants. Sensor variants identified were individually assayed and exhibited up to 60.6-fold (p = 0.0013) improved relative activation by the cognate signal compared to the wildtype. Interestingly, we uncovered prevalent mutational epistasis and previously unidentified residues contributing to signal specificity. The resulting sensors with negligible signal crosstalk could be broadly applied to engineer bacteria consortia.


Assuntos
Proteínas de Bactérias , Transativadores , Transativadores/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transdução de Sinais , Pseudomonas aeruginosa/metabolismo , Mutação , Percepção de Quorum/genética , 4-Butirolactona/metabolismo , Regulação Bacteriana da Expressão Gênica
14.
Metabolites ; 14(1)2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38248847

RESUMO

Engineered microorganisms such as the probiotic strain Escherichia coli Nissle 1917 (EcN) offer a strategy to sense and modulate the concentration of metabolites or therapeutics in the gastrointestinal tract. Here, we present an approach to regulate the production of the depression-associated metabolite gamma-aminobutyric acid (GABA) in EcN using genetic circuits that implement negative feedback. We engineered EcN to produce GABA by overexpressing glutamate decarboxylase and applied an intracellular GABA biosensor to identify growth conditions that improve GABA biosynthesis. We next employed characterized genetically encoded NOT gates to construct genetic circuits with layered feedback to control the rate of GABA biosynthesis and the concentration of GABA produced. Looking ahead, this approach may be utilized to design feedback control of microbial metabolite biosynthesis to achieve designable smart microbes that act as living therapeutics.

15.
Palliat Support Care ; 11(5): 373-82, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23171820

RESUMO

BACKGROUND: The provision of emotional and psychological support for all family members who need it is an essential element of holistic palliative care. Within East Anglia's Children's Hospice, teams of professionally trained and experienced workers offer psychosocial support to all family members at all times during the child's and family's journey. However, the effectiveness and appropriateness of current psychosocial provision is unclear, as is the requirement for any additional psychological services. OBJECTIVE: The purpose of this study was to elicit perceptions about current psychological support within the hospice from a group of stakeholders (parents, hospice staff, and external professionals). METHOD: Forty-five parents participated in family focus groups, telephone interviews, individual interviews in their home, or a web-based survey. Ninety-five hospice staff (including nurses, carers, play specialists, therapists, and family support practitioners) and 28 external staff (including physicians, nurses, and commissioning managers) were seen using a mixture of focus group and individual meetings. Focus groups and meetings were held at the hospice building or at an external venue. Interviews were recorded and transcribed verbatim and analyzed using thematic coding. RESULTS: Two main themes addressing perceptions of current psychological provision emerged: "understanding psychological support" and "unmet psychological need." Subthemes linked to support included choice, staff roles and labels, communication, and flexibility, whereas the themes within unmet need had a stronger focus on people and problems. SIGNIFICANCE OF RESULTS: Understanding different user perspectives is an important first step in enhancing current psychological provision; operationalizing the findings will be challenging.


Assuntos
Cuidados Paliativos na Terminalidade da Vida/psicologia , Cuidados Paliativos/psicologia , Pais/psicologia , Relações Profissional-Família , Estresse Psicológico/prevenção & controle , Adulto , Criança , Serviços de Saúde da Criança/organização & administração , Estado Terminal/psicologia , Crianças com Deficiência/psicologia , Grupos Focais , Humanos , Reino Unido , Adulto Jovem
16.
bioRxiv ; 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37333167

RESUMO

Engineered microorganisms such as the probiotic strain Escherichia coli Nissle 1917 (EcN) offer a strategy to sense and modulate the concentration of metabolites or therapeutics in the gastrointestinal tract. Here, we present an approach to regulate production of the depression-associated metabolite gamma-aminobutyric acid (GABA) in EcN using genetic circuits that implement negative feedback. We engineered EcN to produce GABA by overexpressing glutamate decarboxylase (GadB) from E. coli and applied an intracellular GABA biosensor to identify growth conditions that improve GABA biosynthesis. We next employed characterized genetically-encoded NOT gates to construct genetic circuits with layered feedback to control the rate of GABA biosynthesis and the concentration of GABA produced. Looking ahead, this approach may be utilized to design feedback control of microbial metabolite biosynthesis to achieve designable smart microbes that act as living therapeutics.

17.
ACS Synth Biol ; 12(9): 2632-2649, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37581922

RESUMO

Through the implementation of designable genetic circuits, engineered probiotic microorganisms could be used as noninvasive diagnostic tools for the gastrointestinal tract. For these living cells to report detected biomarkers or signals after exiting the gut, the genetic circuits must be able to record these signals by using genetically encoded memory. Complex memory register circuits could enable multiplex interrogation of biomarkers and signals. A theory-based approach to create genetic circuits containing memory, known as sequential logic circuits, was previously established for a model laboratory strain of Escherichia coli, yet how circuit component performance varies for nonmodel and clinically relevant bacterial strains is poorly understood. Here, we develop a scalable computational approach to design robust sequential logic circuits in probiotic strain Escherichia coli Nissle 1917 (EcN). In this work, we used TetR-family transcriptional repressors to build genetic logic gates that can be composed into sequential logic circuits, along with a set of engineered sensors relevant for use in the gut environment. Using standard methods, 16 genetic NOT gates and nine sensors were experimentally characterized in EcN. These data were used to design and predict the performance of circuit designs. We present a set of genetic circuits encoding both combinational logic and sequential logic and show that the circuit outputs are in close agreement with our quantitative predictions from the design algorithm. Furthermore, we demonstrate an analog-like concentration recording circuit that detects and reports three input concentration ranges of a biochemical signal using sequential logic.


Assuntos
Lógica , Fatores de Transcrição , Fatores de Transcrição/genética , Bactérias/genética , Redes Reguladoras de Genes/genética , Escherichia coli/genética
18.
Front Bioeng Biotechnol ; 10: 938056, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36091463

RESUMO

Engineered probiotic bacteria have been proposed as a next-generation strategy for noninvasively detecting biomarkers in the gastrointestinal tract and interrogating the gut-brain axis. A major challenge impeding the implementation of this strategy has been the difficulty to engineer the necessary whole-cell biosensors. Creation of transcription factor-based biosensors in a clinically-relevant strain often requires significant tuning of the genetic parts and gene expression to achieve the dynamic range and sensitivity required. Here, we propose an approach to efficiently engineer transcription-factor based metabolite biosensors that uses a design prototyping construct to quickly assay the gene expression design space and identify an optimal genetic design. We demonstrate this approach using the probiotic bacterium Escherichia coli Nissle 1917 (EcN) and two neuroactive gut metabolites: the neurotransmitter gamma-aminobutyric acid (GABA) and the short-chain fatty acid propionate. The EcN propionate sensor, utilizing the PrpR transcriptional activator from E. coli, has a large 59-fold dynamic range and >500-fold increased sensitivity that matches biologically-relevant concentrations. Our EcN GABA biosensor uses the GabR transcriptional repressor from Bacillus subtilis and a synthetic GabR-regulated promoter created in this study. This work reports the first known synthetic microbial whole-cell biosensor for GABA, which has an observed 138-fold activation in EcN at biologically-relevant concentrations. Using this rapid design prototyping approach, we engineer highly functional biosensors for specified in vivo metabolite concentrations that achieve a large dynamic range and high output promoter activity upon activation. This strategy may be broadly useful for accelerating the engineering of metabolite biosensors for living diagnostics and therapeutics.

19.
Front Genome Ed ; 4: 892304, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35813973

RESUMO

CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) have become ubiquitous approaches to control gene expression in bacteria due to their simple design and effectiveness. By regulating transcription of a target gene(s), CRISPRi/a can dynamically engineer cellular metabolism, implement transcriptional regulation circuitry, or elucidate genotype-phenotype relationships from smaller targeted libraries up to whole genome-wide libraries. While CRISPRi/a has been primarily established in the model bacteria Escherichia coli and Bacillus subtilis, a growing numbering of studies have demonstrated the extension of these tools to other species of bacteria (here broadly referred to as non-model bacteria). In this mini-review, we discuss the challenges that contribute to the slower creation of CRISPRi/a tools in diverse, non-model bacteria and summarize the current state of these approaches across bacterial phyla. We find that despite the potential difficulties in establishing novel CRISPRi/a in non-model microbes, over 190 recent examples across eight bacterial phyla have been reported in the literature. Most studies have focused on tool development or used these CRISPRi/a approaches to interrogate gene function, with fewer examples applying CRISPRi/a gene regulation for metabolic engineering or high-throughput screens and selections. To date, most CRISPRi/a reports have been developed for common strains of non-model bacterial species, suggesting barriers remain to establish these genetic tools in undomesticated bacteria. More efficient and generalizable methods will help realize the immense potential of programmable CRISPR-based transcriptional control in diverse bacteria.

20.
Front Pharmacol ; 13: 888079, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35959440

RESUMO

A deep understanding of an antimicrobial's critical pharmacokinetic and pharmacodynamic properties is crucial towards optimizing its use in patients and bolstering the drug development program. With the growing threat of antimicrobial resistance and decline in antimicrobial development, the advancement of complex and rigorous pharmacokinetic and pharmacodynamic studies over a short time span has renewed confidence in the value of pharmacokinetic and pharmacodynamic studies and allowed it to become fundamental component of a robust drug development program with high chances of successful approval. In addition, recent guidance by various regulatory bodies have reinforced that a strong and dedicated focus on pharmacokinetics and pharmacodynamics throughout research and development lead to the use of an optimized dosing regimen in Phase 3 trials, improving the probability of drug approval. The objective of this review is to demonstrate the importance of pharmacokinetic and pharmacodynamic studies in the drug development decision-making process by highlighting the developments in pharmacokinetic and pharmacodynamic methods and discuss the role of pharmacokinetic and pharmacodynamic studies in antimicrobial successes and failures.

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