RESUMEN
Lipids have not traditionally been considered likely candidates for catalyzing reactions in biological systems. However, there is significant evidence that aggregates of amphiphilic compounds are capable of catalyzing reactions in synthetic organic chemistry. Here, we demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis by means of a lipid aggregate capable of speeding up a chemical reaction. By bringing organic molecules into the nonpolar or hydrophobic region of a lipid bilayer, reactions can be catalyzed by individual or collections of small, nonpolar, or amphiphilic molecules. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce a fluorescent product, which is a widely used assay for esterase activity in cells. The reaction was first carried out in a two-phase octanol-water system, with the organic phase containing the cationic amphiphiles cetyltrimethylammonium bromide (CTAB) or octadecylamine. The octanol phase was then replaced with phospholipid vesicles in water, where the reaction was also found to be carried out. The reaction was monitored using quantitative fluorescence, which revealed catalytic turnover numbers on a scale of 10-7 to 10-8 s-1 for each system, which is much slower than enzymatic catalysis. The reaction product was characterized by 1H-NMR measurements, which were consistent with ester hydrolysis. The implications of thinking about lipids and lipid aggregates as catalytic entities are discussed in the context of biochemistry, pharmacology, and synthetic biology.
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Unidades de Cuidado Intensivo Neonatal , Humanos , Recién Nacido , Femenino , Masculino , Negro o AfroamericanoRESUMEN
High throughput screening of small molecules and natural products is costly, requiring significant amounts of time, reagents, and operating space. Although microarrays have proven effective in the miniaturization of screening for certain biochemical assays, such as nucleic acid hybridization or antibody binding, they are not widely used for drug discovery in cell culture due to the need for cells to internalize lipophilic drug candidates. Lipid droplet microarrays are a promising solution to this problem as they are capable of delivering lipophilic drugs to cells at dosages comparable to solution delivery. However, the scalablility of the array fabrication, assay validation, and screening steps has limited the utility of this approach. Here we take several new steps to scale up the process for lipid droplet array fabrication, assay validation in cell culture, and drug screening. A nanointaglio printing process has been adapted for use with a printing press. The arrays are stabilized for immersion into aqueous solution using a vapor coating process. In addition to delivery of lipophilic compounds, we found that we are also able to encapsulate and deliver a water-soluble compound in this way. The arrays can be functionalized by extracellular matrix proteins such as collagen prior to cell culture as the mechanism for uptake is based on direct contact with the lipid delivery vehicles rather than diffusion of the drug out of the microarray spots. We demonstrate this method for delivery to 3 different cell types and the screening of 92 natural product extracts on a microarray covering an area of less than 0.1 cm2. The arrays are suitable for miniaturized screening, for instance in high biosafety level facilities where space is limited and for applications where cell numbers are limited, such as in functional precision medicine.
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Gotas Lipídicas , Humanos , Gotas Lipídicas/metabolismo , Análisis por Micromatrices/métodos , Animales , Evaluación Preclínica de Medicamentos/métodos , Ensayos Analíticos de Alto Rendimiento/métodosRESUMEN
BACKGROUND: Despite increases in nursing faculty diversity, representation is lacking in positions of higher faculty rank. Challenges for minority faculty include decreased awareness of promotion standards, less mentoring, and increased stress from being the sole representative of their respective underrepresented population. METHODS: The purpose of this study was to determine the racial, ethnic, and gender composition of neonatal nurse practitioner (NNP) faculty in the United States. A nonexperimental survey was sent to all accredited NNP programs to describe demographics of NNP faculty in the United State. RESULTS: Of the 128 survey participants, 84% self-identified as White. Forty-eight of the participants ranked Professor or Associate professor were White. In contrast, all other races only had 8 respondents who were of the higher faculty ranks. There were only 2 male participants; one identified as full professor and one as associate professor. CONCLUSION: Limitations of this project included a small sample size leading to an inability to determine statistical significance. Previous evidence supports decreased diversity in higher faculty rank in other healthcare providers and the results of this study add to that body of literature. Barriers to increased diversification need to be rectified to ensure health equity to all patients.
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Docentes de Enfermería , Enfermería Neonatal , Enfermeras Practicantes , Humanos , Docentes de Enfermería/estadística & datos numéricos , Femenino , Masculino , Estados Unidos , Enfermeras Practicantes/estadística & datos numéricos , Enfermería Neonatal/normas , Etnicidad/estadística & datos numéricos , Adulto , Diversidad CulturalRESUMEN
Lipids are known to play a vital role in the molecular organization of all cellular life. Molecular recognition is another fundamental biological process that is generally attributed to biological polymers, such as proteins and nucleic acids. However, there is evidence that aggregates of lipids and lipid-like molecules are also capable of selectively binding to or regulating the partitioning of other molecules. We previously demonstrated that a model two-phase octanol/water system can selectively partition Red 40 and Blue 1 dyes added to an aqueous phase, with the selectivity depending on the surfactant (e.g., cetyltrimethylammonium bromide) dissolved in the organic phase. Here, we elucidate the mechanism of molecular recognition in this system by using quantitative partitioning experiments and molecular dynamics (MD) simulations. Our results indicate that the selectivity for the red dye is thermodynamically favored at all surfactant concentrations, while selectivity for the blue dye is kinetically favored at high surfactant concentrations. The kinetic selectivity for the blue dye correlates with the presence of molecular aggregation at the oil-water interface. Coarse-grained MD simulations elucidate nanoscale supramolecular structures that can preferentially bind one small molecule rather than another at an interface, providing a selectively permeable barrier in the absence of proteins. The results suggest a new supramolecular mechanism for molecular recognition with potential applications in drug delivery, drug discovery, and biosensing.
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Surfactantes Pulmonares , Tensoactivos , Tensoactivos/química , Agua/química , Simulación de Dinámica Molecular , Lipoproteínas , Colorantes/químicaRESUMEN
Picorna-like viruses of the order Picornavirales are a poorly defined group of positive-sense, single-stranded RNA viruses that include numerous pathogens known to infect plants, animals, and insects. A new picorna-like viral species was isolated from the wild lime psyllid (WLP), Leuronota fagarae, in the state of Florida, USA, and labelled: Leuronota fagarae picorna-like virus isolate FL (LfPLV-FL). The virus was found to have homology to a picorna-like virus identified in the Asian Citrus Psyllid (ACP), Diaphorina citri, collected in the state of Florida. Computational analysis of RNA extracts from WLP adult heads identified a 10,006-nucleotide sequence encoding a 2,942 amino acid polyprotein with similar functional domain structure to polyproteins of both Dicistroviridae and Iflaviridae. Sequence comparisons of nucleic acid and amino acid translations of the conserved RNA-dependent RNA polymerase, along with the entire N-terminal nonstructural coding region, provided insight into an evolutionary relationship of LfPLV-FL to insect-infecting iflaviruses. Viruses belonging to the family Iflaviridae encode a polyprotein of around 3000 amino acids in length that is processed post-translationally to produce components necessary for replication. The classification of a novel picorna-like virus in L. fagarae, with evolutionary characteristics similar to picorna-like viruses infecting Bactericera cockerelli and D. citri, provides an opportunity to examine virus host specificity, as well as identify critical components of the virus' genome required for successful transmission, infection, and replication. This bioinformatic classification allows for further insight into a novel virus species, and aids in the research of a closely related virus of the invasive psyllid, D. citri, a major pest of Floridian citriculture. The potential use of viral pathogens as expression vectors to manage the spread D. citri is an area that requires additional research; however, it may bring forth an effective control strategy to reduce the transmission of Candidatus Liberibacter asiaticus (CLas), the causative agent of Huanglongbing (HLB).
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Citrus , Hemípteros , Rhizobiaceae , Virus , Animales , Hemípteros/genética , Aminoácidos , Poliproteínas , Enfermedades de las Plantas , Rhizobiaceae/genéticaRESUMEN
Thalli of the endemic epiphytic New Zealand red seaweed Pyrophyllon subtumens are known to contain a high level of xylose and a notable amount of arabinose but the extracted polysaccharide has not been characterised. The linkage/substitution of individual sugars within the water-soluble polysaccharide extract and various derivatives were determined by chemical and spectroscopic methods. No 3-linked sugars nor any d-galactose were found, which excluded agar-, carrageenan- or mixed 3-linked/4-linked ß-d-xylan-type polysaccharides found in many other red macroalgae. Instead, the polysaccharide backbone contained predominantly 4-linked ß-d-xylopyranosyl, 4-linked 3,6-anhydro-l-galactopyranosyl and 4-linked l-galactopyranosyl units. Some of each type of sugar were sulfated at various positions. Some xylosyl units were substituted at the 2- or 3-position with l-arabinosyl units. The polysaccharide is complex and likely contains a range of structures. However, partial sequencing was successfully used to recover and identify a novel disaccharide 4-O-d-xylopyranosyl-3,6-anhdydro-l-galactopyranose, which indicates a unique â4)-ß-d-Xylp-(1 â 4)-3,6-anhydro-l-Galp-(1 â repeat unit in the polysaccharide.
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Rhodophyta , Algas Marinas , Disacáridos , Polisacáridos , Carragenina , GalactosaRESUMEN
BACKGROUND: Neonatal nurse practitioners have a strong presence in the neonatal intensive care unit and are primed to lead efforts to induce change related to health disparities. Underrepresented minority nurse practitioners offer valuable perspectives in the care of underrepresented minority patients. However, there remains a current racial and ethnic discordance between neonatal providers and patients. Efforts to eliminate health disparities must begin before nursing school. The current racial and ethnic composition of neonatal nurse practitioner faculty in comparison to students in the United States is unknown. PURPOSE: The purpose of this study was to determine the racial and ethnic composition of neonatal nurse practitioner faculty and students in the United States and contrast this data with available data for the racial and ethnic composition of the neonatal intensive care unit patient population. METHODS: This cross-sectional study used a nonexperimental survey to describe the racial and ethnic composition of neonatal nurse practitioner faculty and students in the United States. RESULTS: There was no significant difference in the racial and ethnic composition between neonatal nurse practitioner faculty and students. There were significant differences for all race distributions between neonatal nurse practitioner students and neonatal intensive care unit admissions. IMPLICATIONS FOR PRACTICE AND RESEARCH: The discordance between neonatal nurse practitioner students and neonates in the neonatal intensive care unit is important in addressing disparities and begins before nursing school. Identification of barriers and strategies for recruitment and retention of underrepresented minority nursing students and faculty is needed. VIDEO ABSTRACT AVAILABLE AT: https://journals.lww.com/advancesinneonatalcare/pages/video.aspx?v=62.
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Grupos Minoritarios , Enfermeras Practicantes , Recién Nacido , Humanos , Estados Unidos , Estudios Transversales , Grupos Minoritarios/educación , Docentes , EstudiantesRESUMEN
BACKGROUND: Medication administration errors (MAEs) cause preventable patient harm and cost billions of dollars from already-strained healthcare budgets. An emerging factor contributing to these errors is nurse fatigue. Given medication administration is the most frequent clinical task nurses undertake; it is vital to understand how fatigue impacts MAEs. OBJECTIVE: Examine the evidence on the effect of fatigue on MAEs and near misses by registered nurses working in hospital settings. METHOD: Arksey and O'Malley's scoping review framework was used to guide this review and PAGER framework for data extraction and analysis. The PRISMA checklist was completed. Four electronic databases were searched: CINAHL, PubMed, Scopus and PsycINFO. Eligibility criteria included primary peer review papers published in English Language with no date/time limiters applied. The search was completed in August 2021 and focussed on articles that included: (a) registered nurses in hospital settings, (b) MAEs, (c) measures of sleep, hours of work, or fatigue. RESULTS: Thirty-eight studies were included in the review. 82% of the studies identified fatigue to be a contributing factor in MAEs and near misses (NMs). Fatigue is associated with reduced cognitive performance and lack of attention and vigilance. It is associated with poor nursing performance and decreased patient safety. Components of shift work, such as disruption to the circadian rhythm and overtime work, were identified as contributing factors. However, there was marked heterogeneity in strategies for measuring fatigue within the included studies. RELEVANCE TO CLINICAL PRACTICE: Fatigue is a multidimensional concept that has the capacity to impact nurses' performance when engaged in medication administration. Nurses are susceptible to fatigue due to work characteristics such as nightwork, overtime and the requirement to perform cognitively demanding tasks. The mixed results found within this review indicate that larger scale studies are needed with particular emphasis on the impact of overtime work. Policy around safe working hours need to be re-evaluated and fatigue management systems put in place to ensure delivery of safe and quality patient care.
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Enfermeras y Enfermeros , Seguridad del Paciente , Humanos , Preparaciones Farmacéuticas , Hospitales , Fatiga , MentolRESUMEN
BACKGROUND: There are pervasive and documented disparities in maternal and infant outcomes related to race and ethnicity. Critical awareness is growing in our current cultural environment about strategies to improve health equity, the need to challenge implicit bias, and dismantle racism in healthcare to decrease racial health inequities. METHODS: In this article, we provide a summary of health inequities that exist within the perinatal/neonatal population and offer strategies for initiating conversations and improving health equity by challenging bias and increasing diversity. RESULTS: Transformative leaders must understand the evidence related to health disparities, understand social drivers of inequity issues, and identify solutions to influence change. IMPLICATIONS FOR PRACTICE: With heightened awareness and examination of implicit bias, we can improve care for all infants and their families. IMPLICATIONS FOR RESEARCH: We need to continue research and quality improvement efforts to improve health equity. Furthermore, research is needed that focus on social determinants of health as drivers of preterm delivery and birth complications, rather than biological (eg, racialized) factors.Video Abstract available at:https://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx?autoPlay=false&videoId=42.
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Equidad en Salud , Salud del Lactante , Salud Materna , Racismo , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , Determinantes Sociales de la SaludRESUMEN
Information contained in the sequences of biological polymers such as DNA and protein is crucial to determining their function. Lipids are not generally thought of as information-containing molecules. However, from a supramolecular perspective, the number of possible combinations of lipids in a mixture is comparable to the complexity of DNA or proteins. Here, we test the idea that an organic composome can exhibit molecular recognition. We use water/octanol as a model two-phase system and investigate the effect of organic solutes in different combinations in the organic phase on selective partitioning of two water-soluble dyes (Brilliant Blue FCF and Allura Red AC) from the aqueous phase into the organic phase. We found that variation in the concentration of the surfactant cetyltrimethylamonium bromide (CTAB) in the octanol phase alone was sufficient to cause a switch in selectivity, with low CTAB concentrations being selective for the red dye and high CTAB concentrations being selective for the blue dye. Other organic components were added to the organic phase to introduce molecular diversity into the composome and directed evolution was used to optimize the relative concentrations of the solutes. An improvement of selective partitioning in the heterogeneous system over the pure CTAB solution was observed. The results indicate that supramolecular composomes are sufficient for molecular recognition processes in a way analogous to nucleic acid aptamers.
RESUMEN
B. ovatus is a member of the human gut microbiota with a broad capability to degrade complex glycans. Here we show that B. ovatus degrades plant polysaccharides in a preferential order, and that glycan structural complexity plays a role in determining the prioritisation of polysaccharide usage.
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Bacteroides/crecimiento & desarrollo , Bacteroides/metabolismo , Tracto Gastrointestinal/microbiología , Polisacáridos/metabolismo , Microbioma Gastrointestinal , Humanos , Plantas/química , Polisacáridos/químicaRESUMEN
Whole-transcriptome analysis was used to investigate the molecular interplay between three bacterial species that are members of the human gut microbiota. Bacteroides ovatus, Subdoligranulum variabile, and Hungatella hathewayi formed associations in cocultures fed barley ß-glucan, a constituent of dietary fiber. B. ovatus depolymerized ß-glucan and released, but did not utilize, 3-O-ß-cellobiosyl-d-glucose (DP3) and 3-O-ß-cellotriosyl-d-glucose (DP4). These oligosaccharides provided growth substrates for S. variabile and H. hathewayi with a preference for DP4 in the case of the latter species. There was increased transcription of a B. ovatus mixed-linkage-ß-glucan utilization locus, as well as carbohydrate transporters in S. variabile and H. hathewayi when in batch coculture. Increased transcription of the ß-glucan utilization locus did not occur in continuous culture. Evidence for interactions relating to provision of cobalamin, alterations to signaling, and modulation of the "stringent response" (an adaptation to nutrient deprivation) were detected. Overall, we established a bacterial consortium based on barley ß-glucan in vitro, which can be used to investigate aspects of the functional blueprint of the human gut microbiota.IMPORTANCE The microbial community, mostly composed of bacterial species, residing in the human gut degrades and ferments polysaccharides derived from plants (dietary fiber) that would not otherwise be digested. In this way, the collective metabolic actions of community members extract additional energy from the human diet. While the variety of bacteria present in the microbial community is well known, the formation of bacterial consortia, and the consequent interactions that result in the digestion of dietary polysaccharides, has not been studied extensively. The importance of our work was the establishment, under laboratory conditions, of a consortium of gut bacteria that formed around a dietary constituent commonly present in cereals. This enabled the metabolic interplay between the bacterial species to be studied. This kind of knowledge is required to construct an interactive, metabolic blueprint of the microbial community that inhabits the human gut.
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Bacteroides/metabolismo , Clostridiaceae/metabolismo , Clostridiales/metabolismo , Consorcios Microbianos , Transcriptoma , beta-Glucanos/metabolismo , Hordeum/químicaRESUMEN
A knowledge of the mobilities of the polysaccharides or parts of polysaccharides in a cell-wall preparation provides information about possible molecular interactions among the polysaccharides in the cell wall and the relative locations of polysaccharides within the cell wall. A number of solid-state 13C NMR techniques have been developed that can be used to investigate different types of polysaccharide mobilities: rigid, semirigid, mobile, and highly mobile. In this chapter techniques are described for obtaining spectra from primary cell-wall preparations using CP/MAS, proton-rotating frame, proton spin-spin, spin-echo relaxation spectra and single-pulse excitation. We also describe how proton spin relaxation editing can be used to obtain subspectra for cell-wall polysaccharides of different mobilities, and how 2D and 3D solid-state NMR experiments have recently been applied to plant cell walls.
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Espectroscopía de Resonancia Magnética con Carbono-13 , Pared Celular/química , Células Vegetales/química , Difusión , Polisacáridos/química , Protones , Marcadores de SpinRESUMEN
Dietary fiber provides growth substrates for bacterial species that belong to the colonic microbiota of humans. The microbiota degrades and ferments substrates, producing characteristic short-chain fatty acid profiles. Dietary fiber contains plant cell wall-associated polysaccharides (hemicelluloses and pectins) that are chemically diverse in composition and structure. Thus, depending on plant sources, dietary fiber daily presents the microbiota with mixtures of plant polysaccharides of various types and complexity. We studied the extent and preferential order in which mixtures of plant polysaccharides (arabinoxylan, xyloglucan, ß-glucan, and pectin) were utilized by a coculture of five bacterial species (Bacteroides ovatus, Bifidobacterium longum subspecies longum, Megasphaera elsdenii, Ruminococcus gnavus, and Veillonella parvula). These species are members of the human gut microbiota and have the biochemical capacity, collectively, to degrade and ferment the polysaccharides and produce short-chain fatty acids (SCFAs). B. ovatus utilized glycans in the order ß-glucan, pectin, xyloglucan, and arabinoxylan, whereas B. longum subsp. longum utilization was in the order arabinoxylan, arabinan, pectin, and ß-glucan. Propionate, as a proportion of total SCFAs, was augmented when polysaccharide mixtures contained galactan, resulting in greater succinate production by B. ovatus and conversion of succinate to propionate by V. parvula Overall, we derived a synthetic ecological community that carries out SCFA production by the common pathways used by bacterial species for this purpose. Systems like this might be used to predict changes to the emergent properties of the gut ecosystem when diet is altered, with the aim of beneficially affecting human physiology.IMPORTANCE This study addresses the question as to how bacterial species, characteristic of the human gut microbiota, collectively utilize mixtures of plant polysaccharides such as are found in dietary fiber. Five bacterial species with the capacity to degrade polymers and/or produce acidic fermentation products detectable in human feces were used in the experiments. The bacteria showed preferential use of certain polysaccharides over others for growth, and this influenced their fermentation output qualitatively. These kinds of studies are essential in developing concepts of how the gut microbial community shares habitat resources, directly and indirectly, when presented with mixtures of polysaccharides that are found in human diets. The concepts are required in planning dietary interventions that might correct imbalances in the functioning of the human microbiota so as to support measures to reduce metabolic conditions such as obesity.
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Bacterias/metabolismo , Microbioma Gastrointestinal , Técnicas de Cocultivo/métodos , Glucanos/metabolismo , Pectinas/metabolismo , Xilanos/metabolismo , beta-Glucanos/metabolismoRESUMEN
Pectic polysaccharides from New Zealand (NZ) spinach (Tetragonia tetragonioides) and karaka berries (Corynocarpus laevigatus) were extracted and analyzed. NZ spinach polysaccharides comprised mostly homogalacturonan (64.4%) and rhamnogalacturonan I (5.8%), with side chains of arabinan (8.1%), galactan (2.2%), and type II arabinogalactan (7.1%); karaka berry polysaccharides comprised homogalacturonan (21.8%) and rhamnogalacturonan I (10.0%), with greater proportions of side chains (arabinan, 15.6%; galactan, 23.8%; and type II arabinogalactan, 19.3%). Screening of gut commensal Bacteroides showed that six were able to grow on the NZ spinach extract, while five were able to grow on the karaka berry extract. Analysis of the polysaccharides remaining after fermentation, by size-exclusion chromatography and constituent sugar analysis, showed that the Bacteroides species that grew on these two substrates showed preferences for the different pectic polysaccharide types. Our data suggest that, to completely degrade and utilize the complex pectin structures found in plants, members of Bacteroides and other bowel bacteria work as metabolic consortia.
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Aizoaceae/química , Bacteroides/crecimiento & desarrollo , Magnoliopsida/química , Pectinas/metabolismo , Polisacáridos/metabolismo , Bacteroides/metabolismo , Fermentación , Frutas/química , Microbioma Gastrointestinal/fisiología , Nueva Zelanda , Pectinas/análisis , Pectinas/química , Hojas de la Planta/química , Polisacáridos/química , Polisacáridos/aislamiento & purificaciónRESUMEN
Water-soluble, non-starch polysaccharides from plants are used commercially in a wide range of food and non-food applications. The increasing range of applications for natural polysaccharides means that there is growing demand for plant-derived polysaccharides with different functionalities. The geographical isolation of New Zealand and its unique flora presents opportunities to discover new polysaccharides with novel properties for a range of applications. This review brings together data published since the year 2000 on the composition and structure of exudate gums, mucilages, and storage polysaccharides extracted from New Zealand endemic land plants. The structures and properties of these polysaccharides are compared with the structures of similar polysaccharides from other plants. The current commercial use of these polysaccharides is reviewed and their potential for further exploitation discussed.
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Pectin is abundant in modern day diets, as it comprises the middle lamellae and one-third of the dry carbohydrate weight of fruit and vegetable cell walls. Currently there is no specialized model organism for studying pectin fermentation in the human colon, as our collective understanding is informed by versatile glycan-degrading bacteria rather than by specialist pectin degraders. Here we show that the genome of Monoglobus pectinilyticus possesses a highly specialized glycobiome for pectin degradation, unique amongst Firmicutes known to be in the human gut. Its genome encodes a simple set of metabolic pathways relevant to pectin sugar utilization, and its predicted glycobiome comprises an unusual distribution of carbohydrate-active enzymes (CAZymes) with numerous extracellular methyl/acetyl esterases and pectate lyases. We predict the M. pectinilyticus degradative process is facilitated by cell-surface S-layer homology (SLH) domain-containing proteins, which proteomics analysis shows are differentially expressed in response to pectin. Some of these abundant cell surface proteins of M. pectinilyticus share unique modular organizations rarely observed in human gut bacteria, featuring pectin-specific CAZyme domains and the cell wall-anchoring SLH motifs. We observed M. pectinilyticus degrades various pectins, RG-I, and galactan to produce polysaccharide degradation products (PDPs) which are presumably shared with other inhabitants of the human gut microbiome (HGM). This strain occupies a new ecological niche for a primary degrader specialized in foraging a habitually consumed plant glycan, thereby enriching our understanding of the diverse community profile of the HGM.