Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 106
Filtrar
1.
Phytopathology ; 114(1): 177-192, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37486162

RESUMEN

Sweet sorghum (Sorghum bicolor) lines M81-E and Colman were previously shown to differ in responses to Fusarium thapsinum and Macrophomina phaseolina, stalk rot pathogens that can reduce the yields and quality of biomass and extracted sugars. Inoculated tissues were compared for transcriptomic, phenolic metabolite, and enzymatic activity during disease development 3 and 13 days after inoculation (DAI). At 13 DAI, M81-E had shorter mean lesion lengths than Colman when inoculated with either pathogen. Transcripts encoding monolignol biosynthetic and modification enzymes were associated with transcriptional wound (control) responses of both lines at 3 DAI. Monolignol biosynthetic genes were differentially coexpressed with transcriptional activator SbMyb76 in all Colman inoculations, but only following M. phaseolina inoculation in M81-E, suggesting that SbMyb76 is associated with lignin biosynthesis during pathogen responses. In control inoculations, defense-related genes were expressed at higher levels in M81-E than Colman. Line, treatment, and timepoint differences observed in phenolic metabolite and enzyme activities did not account for observed differences in lesions. However, generalized additive models were able to relate metabolites, but not enzyme activities, to lesion length for quantitatively modeling disease progression: in M81-E, but not Colman, sinapic acid levels positively predicted lesion length at 3 DAI when cell wall-bound syringic acid was low, soluble caffeic acid was high, and lactic acid was high, suggesting that sinapic acid may contribute to responses at 3 DAI. These results provide potential gene targets for development of sweet sorghum varieties with increased stalk rot resistance to ensure biomass and sugar quality.


Asunto(s)
Sorghum , Sorghum/genética , Enfermedades de las Plantas/genética , Ácidos Cumáricos/metabolismo , Metabolismo Secundario , Grano Comestible
2.
J Am Chem Soc ; 2023 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-37920956

RESUMEN

The trifluoromethyl (CF3) group is an essential moiety in medicinal chemistry due to its unique physicochemical properties. While trifluoroacetic acid (TFA) is an inexpensive and easily accessible reagent, its use as a source of CF3 is highly challenging due to its high oxidation potential. In this study, we present a novel electrophotochemical approach that enables the use of TFA as the CF3 source for the selective, catalyst- and oxidant-free trifluoromethylation of (hetero)arenes. Key to our approach is the selective oxidation of TFA over arenes, generating CF3 radicals through oxidative decarboxylation. This strategy enables the sustainable and environmentally-friendly synthesis of CF3-, CF2H- and perfluoroalkyl-containing (hetero)arenes with a broad range of substrates. Importantly, our results demonstrate significantly improved chemoselectivity by light irradiation, opening up new possibilities for the synthetic and medicinal applications of TFA as an ideal yet underutilized CF3 source.

3.
Plant Dis ; 107(12): 3984-3995, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37430480

RESUMEN

The drought-resilient crop sorghum (Sorghum bicolor [L.] Moench) is grown worldwide for multiple uses, including forage or potential lignocellulosic bioenergy feedstock. A major impediment to biomass yield and quality are the pathogens Fusarium thapsinum and Macrophomina phaseolina, which cause Fusarium stalk rot and charcoal rot, respectively. These fungi are more virulent with abiotic stresses such as drought. Monolignol biosynthesis plays a critical role in plant defense. The genes Brown midrib (Bmr)6, Bmr12, and Bmr2 encode the monolignol biosynthesis enzymes cinnamyl alcohol dehydrogenase, caffeic acid O-methyltransferase, and 4-coumarate:CoA ligase, respectively. Plant stalks from lines overexpressing these genes and containing bmr mutations were screened for pathogen responses with controlled adequate or deficit watering. Additionally, near-isogenic bmr12 and wild-type lines in five backgrounds were screened for response to F. thapsinum with adequate and deficit watering. All mutant and overexpression lines were no more susceptible than corresponding wild-type under both watering conditions. The bmr2 and bmr12 lines, near-isogenic to wild-type, had significantly shorter mean lesion lengths (were more resistant) than RTx430 wild-type when inoculated with F. thapsinum under water deficit. Additionally, bmr2 plants grown under water deficit had significantly smaller mean lesions when inoculated with M. phaseolina than under adequate-water conditions. When well-watered, bmr12 in cultivar Wheatland and one of two Bmr2 overexpression lines in RTx430 had shorter mean lesion lengths than corresponding wild-type lines. This research demonstrates that modifying monolignol biosynthesis for increased usability may not impair plant defenses but can even enhance resistance to stalk pathogens under drought conditions.


Asunto(s)
Ascomicetos , Sorghum , Sorghum/genética , Sorghum/microbiología , Grano Comestible , Mutación
4.
Implement Sci ; 18(1): 12, 2023 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-37147643

RESUMEN

BACKGROUND: While prior work has revealed conditions that foster policymakers' use of research evidence, few studies have rigorously investigated the effectiveness of theory-based practices. Specifically, policymakers are most apt to use research evidence when it is timely, relevant, brief, and messaged appropriately, as well as when it facilitates interactive engagement. This study sought to experimentally evaluate an enhanced research dissemination intervention, known as the SciComm Optimizer for Policy Engagement (SCOPE), implemented during the COVID-19 pandemic among US state legislators. METHODS: State legislators assigned to health committees and their staff were randomized to receive the SCOPE intervention. This involved providing academic researchers with a pathway for translating and disseminating research relevant to current legislative priorities via fact sheets emailed directly to officials. The intervention occurred April 2020-March 2021. Research language was measured in state legislators' social media posts. RESULTS: Legislators randomized to receive the intervention, relative to the control group, produced 24% more social media posts containing research language related to COVID-19. Secondary analyses revealed that these findings were driven by two different types of research language. Intervention officials produced 67% more COVID-related social media posts referencing technical language (e.g., statistical methods), as well as 28% more posts that referenced research-based concepts. However, they produced 31% fewer posts that referenced creating or disseminating new knowledge. CONCLUSIONS: This study suggests that strategic, targeted science communication efforts may have the potential to change state legislators' public discourse and use of evidence. Strategic science communication efforts are particularly needed in light of the role government officials have played in communicating about the pandemic to the general public.


Asunto(s)
COVID-19 , Humanos , Pandemias , Comunicación , Políticas , Investigación
5.
bioRxiv ; 2023 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-37066321

RESUMEN

Reversal learning measures the ability to form flexible associations between choice outcomes with stimuli and actions that precede them. This type of learning is thought to rely on several cortical and subcortical areas, including highly interconnected orbitofrontal cortex (OFC) and basolateral amygdala (BLA), and is often impaired in various neuropsychiatric and substance use disorders. However, unique contributions of these regions to stimulus- and action-based reversal learning have not been systematically compared using a chemogenetic approach and particularly before and after the first reversal that introduces new uncertainty. Here, we examined the roles of ventrolateral OFC (vlOFC) and BLA during reversal learning. Male and female rats were prepared with inhibitory DREADDs targeting projection neurons in these regions and tested on a series of deterministic and probabilistic reversals during which they learned about stimulus identity or side (left or right) associated with different reward probabilities. Using a counterbalanced within-subject design, we inhibited these regions prior to reversal sessions. We assessed initial and pre-post reversal changes in performance to measure learning and adjustments to reversals, respectively. We found that inhibition of vlOFC, but not BLA, eliminated adjustments to stimulus-based reversals. Inhibition of BLA, but not vlOFC, selectively impaired action-based probabilistic reversal learning, leaving deterministic reversal learning intact. vlOFC exhibited a sex-dependent role in early adjustment to action-based reversals, but not in overall learning. These results reveal dissociable roles for BLA and vlOFC in flexible learning and highlight a more crucial role for BLA in learning meaningful changes in the reward environment.

7.
Proc COMPSAC ; 2021: 774-784, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34568878

RESUMEN

Currently, wired respiratory rate sensors tether patients to a location and can potentially obscure their body from medical staff. In addition, current wired respiratory rate sensors are either inaccurate or invasive. Spurred by these deficiencies, we have developed the Bellyband, a less invasive smart garment sensor, which uses wireless, passive Radio Frequency Identification (RFID) to detect bio-signals. Though the Bellyband solves many physical problems, it creates a signal processing challenge, due to its noisy, quantized signal. Here, we present an algorithm by which to estimate respiratory rate from the Bellyband. The algorithm uses an adaptively parameterized Savitzky-Golay (SG) filter to smooth the signal. The adaptive parameterization enables the algorithm to be effective on a wide range of respiratory frequencies, even when the frequencies change sharply. Further, the algorithm is three times faster and three times more accurate than the current Bellyband respiratory rate detection algorithm and is able to run in real time. Using an off-the-shelf respiratory monitor and metronome-synchronized breathing, we gathered 25 sets of data and tested the algorithm against these trials. The algorithm's respiratory rate estimates diverged from ground truth by an average Root Mean Square Error (RMSE) of 4.1 breaths per minute (BPM) over all 25 trials. Further, preliminary results suggest that the algorithm could be made as or more accurate than widely used algorithms that detect the respiratory rate of non-ventilated patients using data from an Electrocardiogram (ECG) or Impedance Plethysmography (IP).

8.
BMC Plant Biol ; 21(1): 391, 2021 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-34418969

RESUMEN

BACKGROUND: As effects of global climate change intensify, the interaction of biotic and abiotic stresses increasingly threatens current agricultural practices. The secondary cell wall is a vanguard of resistance to these stresses. Fusarium thapsinum (Fusarium stalk rot) and Macrophomina phaseolina (charcoal rot) cause internal damage to the stalks of the drought tolerant C4 grass, sorghum (Sorghum bicolor (L.) Moench), resulting in reduced transpiration, reduced photosynthesis, and increased lodging, severely reducing yields. Drought can magnify these losses. Two null alleles in monolignol biosynthesis of sorghum (brown midrib 6-ref, bmr6-ref; cinnamyl alcohol dehydrogenase, CAD; and bmr12-ref; caffeic acid O-methyltransferase, COMT) were used to investigate the interaction of water limitation with F. thapsinum or M. phaseolina infection. RESULTS: The bmr12 plants inoculated with either of these pathogens had increased levels of salicylic acid (SA) and jasmonic acid (JA) across both watering conditions and significantly reduced lesion sizes under water limitation compared to adequate watering, which suggested that drought may prime induction of pathogen resistance. RNA-Seq analysis revealed coexpressed genes associated with pathogen infection. The defense response included phytohormone signal transduction pathways, primary and secondary cell wall biosynthetic genes, and genes encoding components of the spliceosome and proteasome. CONCLUSION: Alterations in the composition of the secondary cell wall affect immunity by influencing phenolic composition and phytohormone signaling, leading to the action of defense pathways. Some of these pathways appear to be activated or enhanced by drought. Secondary metabolite biosynthesis and modification in SA and JA signal transduction may be involved in priming a stronger defense response in water-limited bmr12 plants.


Asunto(s)
Adaptación Fisiológica/genética , Sequías , Lignina/biosíntesis , Lignina/genética , Sorghum/química , Sorghum/genética , Sorghum/microbiología , Ascomicetos/patogenicidad , Pared Celular/química , Pared Celular/genética , Grano Comestible/química , Grano Comestible/genética , Grano Comestible/microbiología , Fusarium/patogenicidad , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Variación Genética , Genotipo , Interacciones Huésped-Patógeno/genética , Mutación , Transducción de Señal , Estados Unidos , Agua/metabolismo
9.
Neuron ; 109(11): 1791-1809.e11, 2021 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-33979635

RESUMEN

Optical manipulations of genetically defined cell types have generated significant insights into the dynamics of neural circuits. While optogenetic activation has been relatively straightforward, rapid and reversible synaptic inhibition has proven more elusive. Here, we leveraged the natural ability of inhibitory presynaptic GPCRs to suppress synaptic transmission and characterize parapinopsin (PPO) as a GPCR-based opsin for terminal inhibition. PPO is a photoswitchable opsin that couples to Gi/o signaling cascades and is rapidly activated by pulsed blue light, switched off with amber light, and effective for repeated, prolonged, and reversible inhibition. PPO rapidly and reversibly inhibits glutamate, GABA, and dopamine release at presynaptic terminals. Furthermore, PPO alters reward behaviors in a time-locked and reversible manner in vivo. These results demonstrate that PPO fills a significant gap in the neuroscience toolkit for rapid and reversible synaptic inhibition and has broad utility for spatiotemporal control of inhibitory GPCR signaling cascades.


Asunto(s)
Inhibición Neural , Optogenética/métodos , Terminales Presinápticos/metabolismo , Recompensa , Transmisión Sináptica , Animales , Dopamina/metabolismo , Exocitosis , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Ácido Glutámico/metabolismo , Células HEK293 , Células HeLa , Humanos , Masculino , Ratones , Terminales Presinápticos/fisiología , Receptores Acoplados a Proteínas G/metabolismo , Opsinas de Bastones/genética , Opsinas de Bastones/metabolismo , Ácido gamma-Aminobutírico/metabolismo
10.
Stress Health ; 37(1): 32-44, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32602640

RESUMEN

This study examines the psychometric properties of a new multidimensional job insecurity measure (JIM) by O'Neill and Sevastos in a Chinese context. Overall, the results corroborate the construct validity, reliability and criterion-related validity of the JIM. Based on the results of the exploratory factor analysis, the new scale has 15 items and three items were removed from the dimensions of job loss and job change because of differences in culture and understanding between Chinese and Western employees. Additionally, the relationship between job insecurity and theoretically viable antecedents (three different types of conflicts) and outcomes (i.e., job satisfaction and counterproductive work behaviour) were also examined, and the results show that the three conflicts are effective predictors of job insecurity and job insecurity is predictor of outcomes variables. All findings show that this new JIM is more parsimonious and more effective in assessing job insecurity in the Chinese context.


Asunto(s)
Empleo , Encuestas y Cuestionarios , China , Empleo/psicología , Análisis Factorial , Humanos , Psicometría , Reproducibilidad de los Resultados
11.
Plant Dis ; 104(11): 2807-2816, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32954986

RESUMEN

Spongospora subterranea is a soilborne plasmodiophorid that causes powdery scab in potato. It also transmits potato mop-top virus (PMTV), which causes necrotic arcs (spraing) in potato tubers. Three field experiments were conducted in naturally S. subterranea-infested soil to investigate the effects of two chemicals, Omega 500F (fluazinam) and FOLI-R-PLUS RIDEZ (biological extract), on powdery scab, PMTV, and changes in S. subterranea inoculum with six different potato cultivars. The efficacy of soil treatment with these two chemicals on tuber lesions, root galling, and pathogen population was also assessed in greenhouse trials. The chemical treatments did not reduce powdery scab, root gall formation, or S. subterranea inoculum in the field or greenhouse trials. Postharvest S. subterranea soil inoculum in fields varied across farms and among potato cultivars but the pathogen population consistently increased by the end of the growing season. The evaluated russet cultivars were more tolerant to powdery scab than the yellow- or red-skinned cultivars but all were susceptible to PMTV. In the field, powdery scab indices and soil inoculum changes were positively correlated, while postharvest S. subterranea inoculum was positively correlated with root galling in both greenhouse trials. Powdery scab and PMTV occurred in noninoculated potting mix, indicating that peat-based potting mix is a source for both pathogens. These results demonstrate that chemical management methods currently used by farmers are ineffective, that S. subterranea and PMTV in potting mix can cause severe epidemics in greenhouses, and that potato cultivar choices impact inoculum increases in soil.


Asunto(s)
Virus de Plantas , Plasmodiophorida , Solanum tuberosum , Incidencia , Enfermedades de las Plantas , Polvos , Suelo
12.
JAMA Netw Open ; 3(7): e209393, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32663307

RESUMEN

Importance: Trauma is the leading cause of death for US individuals younger than 45 years, and uncontrolled hemorrhage is a major cause of trauma mortality. The US military's medical advancements in the field of prehospital hemorrhage control have reduced battlefield mortality by 44%. However, despite support from many national health care organizations, no integrated approach to research has been made regarding implementation, epidemiology, education, and logistics of prehospital hemorrhage control by layperson immediate responders in the civilian sector. Objective: To create a national research agenda to help guide future work for prehospital hemorrhage control by laypersons. Evidence Review: The 2-day, in-person, National Stop the Bleed (STB) Research Consensus Conference was conducted on February 27 to 28, 2019, to identify and achieve consensus on research gaps. Participants included (1) subject matter experts, (2) professional society-designated leaders, (3) representatives from the federal government, and (4) representatives from private foundations. Before the conference, participants were provided a scoping review on layperson prehospital hemorrhage control. A 3-round modified Delphi consensus process was conducted to determine high-priority research questions. The top items, with median rating of 8 or more on a Likert scale of 1 to 9 points, were identified and became part of the national STB research agenda. Findings: Forty-five participants attended the conference. In round 1, participants submitted 487 research questions. After deduplication and sorting, 162 questions remained across 5 a priori-defined themes. Two subsequent rounds of rating generated consensus on 113 high-priority, 27 uncertain-priority, and 22 low-priority questions. The final prioritized research agenda included the top 24 questions, including 8 for epidemiology and effectiveness, 4 for materials, 9 for education, 2 for global health, and 1 for health policy. Conclusions and Relevance: The National STB Research Consensus Conference identified and prioritized a national research agenda to support laypersons in reducing preventable deaths due to life-threatening hemorrhage. Investigators and funding agencies can use this agenda to guide their future work and funding priorities.


Asunto(s)
Servicios Médicos de Urgencia , Hemorragia , Proyectos de Investigación , Heridas y Lesiones , Investigación Biomédica/métodos , Consenso , Técnica Delphi , Servicios Médicos de Urgencia/métodos , Servicios Médicos de Urgencia/organización & administración , Hemorragia/etiología , Hemorragia/mortalidad , Hemorragia/terapia , Humanos , Encuestas y Cuestionarios , Heridas y Lesiones/complicaciones , Heridas y Lesiones/mortalidad
13.
Plant Dis ; 103(9): 2277-2287, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31215851

RESUMEN

To increase phenylpropanoid constituents and energy content in the versatile C4 grass sorghum (Sorghum bicolor [L.] Moench), sorghum genes for proteins related to monolignol biosynthesis were overexpressed: SbMyb60 (transcriptional activator), SbPAL (phenylalanine ammonia lyase), SbCCoAOMT (caffeoyl coenzyme A [CoA] 3-O-methyltransferase), Bmr2 (4-coumarate:CoA ligase), and SbC3H (coumaroyl shikimate 3-hydroxylase). Overexpression lines were evaluated for responses to stalk pathogens under greenhouse and field conditions. Greenhouse-grown plants were inoculated with Fusarium thapsinum (Fusarium stalk rot) and Macrophomina phaseolina (charcoal rot), which cause yield-reducing diseases. F. thapsinum-inoculated overexpression plants had mean lesion lengths not significantly different than wild-type, except for significantly smaller lesions on two of three SbMyb60 and one of two SbCCoAOMT lines. M. phaseolina-inoculated overexpression lines had lesions not significantly different from wild-type except one SbPAL line (of two lines studied) with mean lesion lengths significantly larger. Field-grown SbMyb60 and SbCCoAOMT overexpression plants were inoculated with F. thapsinum. Mean lesions of SbMyb60 lines were similar to wild-type, but one SbCCoAOMT had larger lesions, whereas the other line was not significantly different than wild-type. Because overexpression of SbMyb60, Bmr2, or SbC3H may not render sorghum more susceptible to stalk rots, these lines may provide sources for development of sorghum with increased phenylpropanoid concentrations.


Asunto(s)
Ascomicetos , Fusarium , Regulación de la Expresión Génica de las Plantas , Lignina , Sorghum , Ascomicetos/fisiología , Fusarium/fisiología , Genes de Plantas/genética , Lignina/biosíntesis , Lignina/genética , Sorghum/genética , Sorghum/microbiología
14.
Sci Signal ; 12(574)2019 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-30914485

RESUMEN

Agonists of the nociceptin/orphanin FQ opioid peptide (NOP) receptor, a member of the opioid receptor family, are under active investigation as novel analgesics, but their modes of signaling are less well characterized than those of other members of the opioid receptor family. Therefore, we investigated whether different NOP receptor ligands showed differential signaling or functional selectivity at the NOP receptor. Using newly developed phosphosite-specific antibodies to the NOP receptor, we found that agonist-induced NOP receptor phosphorylation occurred primarily at four carboxyl-terminal serine (Ser) and threonine (Thr) residues, namely, Ser346, Ser351, Thr362, and Ser363, and proceeded with a temporal hierarchy, with Ser346 as the first site of phosphorylation. G protein-coupled receptor kinases 2 and 3 (GRK2/3) cooperated during agonist-induced phosphorylation, which, in turn, facilitated NOP receptor desensitization and internalization. A comparison of structurally distinct NOP receptor agonists revealed dissociation in functional efficacies between G protein-dependent signaling and receptor phosphorylation. Furthermore, in NOP-eGFP and NOP-eYFP mice, NOP receptor agonists induced multisite phosphorylation and internalization in a dose-dependent and agonist-selective manner that could be blocked by specific antagonists. Our study provides new tools to study ligand-activated NOP receptor signaling in vitro and in vivo. Differential agonist-selective NOP receptor phosphorylation by chemically diverse NOP receptor agonists suggests that differential signaling by NOP receptor agonists may play a role in NOP receptor ligand pharmacology.


Asunto(s)
Receptores Opioides/agonistas , Secuencia de Aminoácidos , Animales , Especificidad de Anticuerpos , Relación Dosis-Respuesta a Droga , Quinasa 2 del Receptor Acoplado a Proteína-G/metabolismo , Quinasa 3 del Receptor Acoplado a Proteína-G/metabolismo , Genes Reporteros , Células HEK293 , Humanos , Ligandos , Ratones , Modelos Moleculares , Fosforilación , Fosfoserina/análisis , Fosfotreonina/análisis , Procesamiento Proteico-Postraduccional , Receptores Opioides/inmunología , Receptores Opioides/metabolismo , Proteínas Recombinantes/metabolismo , Relación Estructura-Actividad , Receptor de Nociceptina
15.
Plant Dis ; 103(5): 972-983, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30840842

RESUMEN

Hexaploid waxy wheat (Triticum aestivum L.) has null mutations in Wx genes and grain lacking amylose with increased digestibility and usability for specialty foods. The waxy cultivar Mattern is susceptible to Fusarium head blight (FHB) caused by Fusarium graminearum species complex, which produces the mycotoxin deoxynivalenol (DON). In experiment 1, conducted during low natural FHB, grain from waxy breeding lines, Mattern, and wild-type breeding lines and cultivars were assessed for Fusarium infection and DON concentration. Nine Fusarium species and species complexes were detected from internally infected (disinfested) grain; F. graminearum infections were not different between waxy and wild-type. Surface- and internally infected grain (nondisinfested) had greater numbers of Fusarium isolates across waxy versus wild-type, but F. graminearum-like infections were similar; however, DON levels were higher in waxy. In experiment 2, conducted during a timely epidemic, disease severity, Fusarium-damaged kernels (FDK), and DON were assessed for waxy breeding lines, Mattern, and wild-type cultivars. Disease severity and FDK were not significantly different from wild-type, but DON was higher in waxy than wild-type lines. Across both experiments, waxy breeding lines, Plant Introductions 677876 and 677877, responded similarly to FHB as moderately resistant wild-type cultivar Overland, showing promise for breeding advanced waxy cultivars with reduced FHB susceptibility.


Asunto(s)
Fusarium , Triticum , Amilosa , Resistencia a la Enfermedad/fisiología , Fusarium/enzimología , Fusarium/fisiología , Enfermedades de las Plantas/microbiología , Triticum/microbiología
16.
ACS Synth Biol ; 8(3): 498-510, 2019 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-30764607

RESUMEN

Cells experience physical deformations to the plasma membrane that can modulate cell behaviors like migration. Understanding the molecular basis for how physical cues affect dynamic cellular responses requires new approaches that can physically perturb the plasma membrane with rapid, reversible, subcellular control. Here we present an optogenetic approach based on light-inducible dimerization that alters plasma membrane properties by recruiting cytosolic proteins at high concentrations to a target site. Surprisingly, this polarized accumulation of proteins in a cell induces directional amoeboid migration in the opposite direction. Consistent with known effects of constraining high concentrations of proteins to a membrane in vitro, there is localized curvature and tension decrease in the plasma membrane. Integrin activity, sensitive to mechanical forces, is activated in this region. Localized mechanical activation of integrin with optogenetics allowed simultaneous imaging of the molecular and cellular response, helping uncover a positive feedback loop comprising SFK- and ERK-dependent RhoA activation, actomyosin contractility, rearward membrane flow, and membrane tension decrease underlying this mode of cell migration.


Asunto(s)
Membrana Celular/metabolismo , Movimiento Celular/fisiología , Integrinas/metabolismo , Espacio Intracelular/metabolismo , Optogenética/métodos , Actomiosina/metabolismo , Animales , Movimiento Celular/efectos de la radiación , Proteínas de Unión a Ácidos Grasos/metabolismo , Retroalimentación Fisiológica/fisiología , Luz , Sistema de Señalización de MAP Quinasas , Ratones , Multimerización de Proteína/efectos de la radiación , Células RAW 264.7 , Transducción de Señal/fisiología , Transfección , Proteína de Unión al GTP rhoA/metabolismo
17.
Dev Cell ; 46(1): 9-22.e4, 2018 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-29937389

RESUMEN

Cells migrate by applying rearward forces against extracellular media. It is unclear how this is achieved in amoeboid migration, which lacks adhesions typical of lamellipodia-driven mesenchymal migration. To address this question, we developed optogenetically controlled models of lamellipodia-driven and amoeboid migration. On a two-dimensional surface, migration speeds in both modes were similar. However, when suspended in liquid, only amoeboid cells exhibited rapid migration accompanied by rearward membrane flow. These cells exhibited increased endocytosis at the back and membrane trafficking from back to front. Genetic or pharmacological perturbation of this polarized trafficking inhibited migration. The ratio of cell migration and membrane flow speeds matched the predicted value from a model where viscous forces tangential to the cell-liquid interface propel the cell forward. Since this mechanism does not require specific molecular interactions with the surrounding medium, it can facilitate amoeboid migration observed in diverse microenvironments during immune function and cancer metastasis.


Asunto(s)
Membrana Celular/metabolismo , Movimiento Celular/fisiología , Seudópodos/fisiología , Actomiosina/metabolismo , Animales , Adhesión Celular/fisiología , Línea Celular Transformada , Endocitosis/fisiología , Ratones , Células RAW 264.7 , Receptores Acoplados a Proteínas G/metabolismo , Proteínas de Unión al GTP rho/metabolismo , Proteína de Unión al GTP rhoA
18.
Methods Mol Biol ; 1749: 313-324, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29526006

RESUMEN

Subcellular optogenetics allows specific proteins to be optically activated or inhibited at a restricted subcellular location in intact living cells. It provides unprecedented control of dynamic cell behaviors. Optically modulating the activity of signaling molecules on one side of a cell helps optically control cell polarization and directional cell migration. Combining subcellular optogenetics with live cell imaging of the induced molecular and cellular responses in real time helps decipher the spatially and temporally dynamic molecular mechanisms that control a stereotypical complex cell behavior, cell migration. Here we describe methods for optogenetic control of cell migration by targeting three classes of key signaling switches that mediate directional cellular chemotaxis-G protein coupled receptors (GPCRs), heterotrimeric G proteins, and Rho family monomeric G proteins.


Asunto(s)
Movimiento Celular/fisiología , Optogenética/métodos , Animales , Movimiento Celular/genética , Ratones , Microscopía Fluorescente , Multimerización de Proteína/genética , Multimerización de Proteína/fisiología , Células RAW 264.7 , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/genética , Transducción de Señal/fisiología
19.
Surg Infect (Larchmt) ; 19(4): 376-381, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29565726

RESUMEN

BACKGROUND: Fungi frequently are isolated in intra-abdominal infections (IAI). The Study to Optimize Peritoneal Infection Therapy (STOP-IT) recently suggested short-course treatment for patients with IAI. It remains unclear whether the presence of fungi in IAI affects the optimal duration of Antimicrobial therapy. We hypothesized that a shorter treatment course in IAI with fungal organisms would be associated with a higher rate of treatment failure. METHODS: Patients enrolled in the STOP-IT trial were stratified according to the presence or absence of a fungal isolate. They were analyzed as a subgroup based on original randomization to either the control group or an experimental group that received a four-day course of Antimicrobial therapy and by comparison with those without a fungal component to their infection. Descriptive comparisons were performed using a χ2, Fisher exact, or Kruskal-Wallis test as appropriate. The primary outcome was a composite of recurrent IAI, surgical site infection, and death. RESULTS: A total of 411 patients in the study (79%) had available culture data, of which 58 (14%) had positive fungal cultures. The most common organisms were Candida albicans and C. glabrata. The treatment failure rate was equivalent in the experimental and control arms (29.6% vs. 22.6%; p = 0.54). Patients with fungal isolates were more likely to have malignant disease (25.9% vs. 9.6%; p = 0.0004) and coronary artery disease (22% vs. 12%; p = 0.04), but were otherwise similar to those without fungal isolates. Patients with fungal isolates had more hospital days (median 10 vs. 7; p < 0.0001) and more days to resumption of enteral intake (median 5 vs. 3; p = 0.0006), but there was no difference in the composite outcome. CONCLUSIONS: Patients with IAI involving fungal organisms randomized to a shorter course of Antimicrobial therapy had no difference in the rate of treatment failure. These results suggest that the presence of fungi in IAI may not indicate independently the need for a longer course of Antimicrobial therapy.


Asunto(s)
Antiinfecciosos/administración & dosificación , Quimioterapia/métodos , Infecciones Intraabdominales/tratamiento farmacológico , Micosis/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Infecciones Intraabdominales/microbiología , Masculino , Persona de Mediana Edad , Micosis/microbiología , Factores de Tiempo , Insuficiencia del Tratamiento , Adulto Joven
20.
Surg Neurol Int ; 8: 283, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29279800

RESUMEN

BACKGROUND: The failure rate for the closed/non-surgical treatment of thoracic and lumbar vertebral body fractures (TLVBF) in trauma patients has not been adequately evaluated utilizing computed tomography (CT) studies. METHODS: From 2007 to 2008, consecutive trauma patients, who met inclusion criteria, with a CT diagnosis of acute TLVBF undergoing closed treatment were assessed. The failure rates for closed therapy, at 3 months post-trauma, were defined by progressive deformity, vertebral body collapse, or symptomatic/asymptomatic pseudarthrosis. The Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification was utilized to classify the fractures (groups A1 and non-A1 fractures) and were successively followed with CT studies. RESULTS: There were 54 patients with 91 fractures included in the study; 66 were A1 fractures, and 25 were non-A1 fractures. All had rigid bracing applied with flat and upright X-ray films performed to rule out instability. None had sustained spinal cord injuries. Thirteen patients (24%) failed closed therapy [e.g. 13 failed fractures (14%) out of 91 total fractures]. Five failed radiographically only (asymptomatic), and eight failed radiographically and clinically (symptomatic). A1 fractures had a 4.5% failure rate, while non-A1 fractures failed at a rate of 40%. CONCLUSION: Failure of closed therapy for TLVBF in the trauma population is not insignificant. Non-A1 fractures had a much higher failure rate when compared to A1 fractures. We recommend close follow-up particularly of non-A1 fractures treated in closed fashion using successive CT studies.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...