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1.
J Emerg Med ; 67(1): e60-e64, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38825530

RESUMEN

BACKGROUND: Idiopathic carotidynia, also known as transient perivascular inflammation of the carotid artery (TIPIC) syndrome, is a rare, self-limited, clinical-radiologic entity. Over the years, the diagnosis of carotidynia has been controversial, but recent pathologic, radiologic, clinical, and laboratory findings support an inflammatory etiology. CASE REPORT: A 61-year-old woman with a history of hypertension, left lower extremity liposarcoma, and right internal jugular port placement 2 weeks prior with initiation of chemotherapy presented to the emergency department with right neck pain and swelling of the lateral neck and lower face for the past 3 days. Computed tomography-neck with IV contrast revealed marked mural thickening of the right common carotid artery, which can be seen with carotidynia (Fay syndrome and TIPIC syndrome) and vasculitis. The patient had elevated inflammatory markers and was treated clinically for carotidynia with ibuprofen, evaluated by vascular surgery, and discharged home. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The causes of acute neck pain are diverse, ranging from nonemergent to surgically emergent etiologies. As radiologists and emergency physicians, we believe TIPIC syndrome is a rare entity with important clinical impact deserving attention, as it is not typically included in medical training and is usually learned only through years of clinical experience and practice. TIPIC syndrome requires a unique combination of both clinical and radiologic findings to diagnose accurately and appropriately. It is important to be familiar with this diagnosis because treatment is focused on symptomatic relief without the need for invasive procedures. Our goal was to increase awareness of this uncommon diagnosis to improve patient care by preventing unnecessary invasive procedures and aid in timely and accurate diagnosis.


Asunto(s)
Tomografía Computarizada por Rayos X , Humanos , Femenino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X/métodos , Dolor de Cuello/etiología , Enfermedades de las Arterias Carótidas/diagnóstico , Enfermedades de las Arterias Carótidas/complicaciones , Ibuprofeno/uso terapéutico , Inflamación , Servicio de Urgencia en Hospital/organización & administración , Vasculitis/complicaciones , Vasculitis/diagnóstico , Síndrome
2.
Nature ; 543(7647): 647-656, 2017 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-28358065

RESUMEN

Coherence phenomena arise from interference, or the addition, of wave-like amplitudes with fixed phase differences. Although coherence has been shown to yield transformative ways for improving function, advances have been confined to pristine matter and coherence was considered fragile. However, recent evidence of coherence in chemical and biological systems suggests that the phenomena are robust and can survive in the face of disorder and noise. Here we survey the state of recent discoveries, present viewpoints that suggest that coherence can be used in complex chemical systems, and discuss the role of coherence as a design element in realizing function.


Asunto(s)
Biofisica , Modelos Biológicos , Modelos Químicos , Electrones , Transferencia de Energía , Metales/química , Modelos Moleculares , Movimiento (Física) , Teoría Cuántica , Análisis Espectral , Factores de Tiempo , Vibración
3.
Am J Emerg Med ; 73: 235.e1-235.e3, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37517873

RESUMEN

Foreign body aspiration accounts for 7% of accidental deaths in children under age 4 (4). Children between the ages of 6 months and 3 years of age, adolescent boys and children with mental health issues are at the highest risk of foreign body ingestion. Coins are the most commonly swallowed foreign body in the United States (US) and in other countries those related food such as fish bones are most common (10). Most cases are accidental and pass harmlessly through the gastrointestinal tract with low mortality (10). The most common complication is esophageal obstruction particularly at the thoracic inlet. However, the object can become lodged anywhere in the gastrointestinal tract. We present an unusual case of small bowel obstruction and bowel ischemia secondary to superabsorbent polymer water bead ingestion in a pediatric patient.

4.
Am J Emerg Med ; 45: 684.e1-684.e3, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33388184

RESUMEN

This case highlights the unusual life-threatening findings found in a patient with Marfan syndrome (MFS) in the emergency department setting. MFS is a rare autosomal dominant disease that affects 1 in 3000-5000 individuals and has a highly variable range of clinical severity. This case is a 63-year-old male with COPD, scoliosis, aortic and mitral valve replacements on warfarin, and MFS who presented with acute onset hemoptysis, tachypnea, and oxygen saturation of 77% on 4 l nasal cannula. Emergent chest computed tomography angiography (CTA) revealed both a contained rupture of a left subclavian artery aneurysm and active extravasation from his left internal mammary artery (LIMA) into his left chest. The patient was on warfarin and reversed with IV vitamin K and prothrombin complex concentrate. Vascular surgery emergently took the patient to the operating room for embolization of his LIMA and stenting of the contained ruptured left subclavian artery aneurysm. The patient was discharged home one month after admission. This case report illustrates the potential severe sequelae of MFS and the importance of rapid recognition by emergency physicians. An expanded understanding of the pathophysiology of MFS has resulted in great advancement in medical therapies and lifestyle modification and thus has significantly prolonged life expectancy in these patients. Increased awareness and familiarity will facilitate continued high-quality management and treatment by emergency physicians.


Asunto(s)
Aneurisma Roto/diagnóstico , Síndrome de Marfan/complicaciones , Aneurisma Roto/etiología , Aneurisma Roto/cirugía , Angiografía por Tomografía Computarizada , Hemoptisis/etiología , Humanos , Masculino , Arterias Mamarias/diagnóstico por imagen , Síndrome de Marfan/fisiopatología , Síndrome de Marfan/terapia , Persona de Mediana Edad , Arteria Subclavia/diagnóstico por imagen
5.
Phys Rev Lett ; 122(1): 010403, 2019 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-31012639

RESUMEN

How the objective everyday world emerges from the underlying quantum behavior of its microscopic constituents is an open question at the heart of the foundations of quantum mechanics. Quantum Darwinism and spectrum broadcast structure are two different frameworks providing key insight into this question. Recent works, however, indicate these two frameworks can lead to conflicting predictions on the objectivity of the state of a system interacting with an environment. Here, we provide a resolution to this issue by defining strong quantum Darwinism and proving that it is equivalent to spectrum broadcast structure when combined with strong independence of the subenvironments. We further show that strong quantum Darwinism is sufficient and necessary to signal state objectivity without the requirement of strong independence. Our Letter unveils the deep connection between strong quantum Darwinism and spectrum broadcast structure, thereby making fundamental progress toward understanding and solving the emergence of classicality from the quantum world. Together they provide us a sharper understanding of the transition in terms of state structure, geometry, and quantum and classical information.

6.
Faraday Discuss ; 216(0): 38-56, 2019 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-31062011

RESUMEN

Synchronisation is a collective phenomenon widely investigated in classical oscillators and, more recently, in quantum systems. However it remains unclear what features distinguish synchronous behaviour in these two scenarios. Recent works have shown that investigating synchronisation dynamics in open quantum systems can give insight into this issue. Here we study transient synchronisation in a bio-inspired vibronic dimer, where electronic excitation dynamics is mediated by coherent interactions with intramolecular vibrational modes. We show that the synchronisation dynamics of local mode displacements exhibit a rich behaviour which arises directly from the distinct time-evolutions of different vibronic quantum coherences. Furthermore, our study shows that coherent energy transport in this bio-inspired system is concomitant with the emergence of positive synchronisation between mode displacements. Our work provides further understanding of the relations between quantum coherence and synchronisation in open quantum systems and suggests an interesting role for coherence in biomolecules, that of promoting synchronisation of vibrational motions driven out of thermal equilibrium.


Asunto(s)
Pigmentos Biológicos/química , Proteínas/química , Teoría Cuántica , Dimerización , Transferencia de Energía , Fotosíntesis , Pigmentos Biológicos/metabolismo , Proteínas/metabolismo , Vibración
7.
Opt Express ; 25(6): 6383-6401, 2017 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-28380990

RESUMEN

The full development of mono- or multi-dimensional time-resolved spectroscopy techniques incorporating optical activity signals has been strongly hampered by the challenge of identifying the small chiral signals over the large achiral background. Here we propose a new methodology to isolate chiral signals removing the achiral background from two commonly used configurations for performing two-dimensional optical spectroscopy, known as BOXCARS and gradient assisted photon echo spectroscopy (GRAPES). It is found that in both cases an achiral signal from an isotropic system can be completely eliminated by small manipulations of the relative angles between the linear polarizations of the four input laser pulses. Starting from the formulation of a perturbative expansion of the signal in the angle between the beams and the propagation axis, we derive analytic expressions that can be used to estimate how to change the polarization angles of the four pulses to minimize achiral contributions in the studied configurations. The generalization to any other possible experimental configurations has also been discussed.

8.
Phys Rev Lett ; 126(18): 188902, 2021 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-34018781
9.
J Chem Phys ; 144(19): 194112, 2016 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-27208941

RESUMEN

We examine transient circular dichroism (TRCD) spectroscopy as a technique to investigate signatures of exciton coherence dynamics under the influence of structured vibrational environments. We consider a pump-probe configuration with a linearly polarized pump and a circularly polarized probe, with a variable angle θ between the two directions of propagation. In our theoretical formalism the signal is decomposed in chiral and achiral doorway and window functions. Using this formalism, we show that the chiral doorway component, which beats during the population time, can be isolated by comparing signals with different values of θ. As in the majority of time-resolved pump-probe spectroscopy, the overall TRCD response shows signatures of both excited and ground state dynamics. However, we demonstrate that the chiral doorway function has only a weak ground state contribution, which can generally be neglected if an impulsive pump pulse is used. These findings suggest that the pump-probe configuration of optical TRCD in the impulsive limit has the potential to unambiguously probe quantum coherence beating in the excited state. We present numerical results for theoretical signals in an example dimer system.

10.
BMC Plant Biol ; 15: 45, 2015 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-25848849

RESUMEN

BACKGROUND: Plant α-dioxygenases catalyze the incorporation of molecular oxygen into polyunsaturated fatty acids leading to the formation of oxylipins. In flowering plants, two main groups of α-DOXs have been described. While the α-DOX1 isoforms are mainly involved in defense responses against microbial infection and herbivores, the α-DOX2 isoforms are mostly related to development. To gain insight into the roles played by these enzymes during land plant evolution, we performed biochemical, genetic and molecular analyses to examine the function of the single copy moss Physcomitrella patens α-DOX (Ppα-DOX) in development and defense against pathogens. RESULTS: Recombinant Ppα-DOX protein catalyzed the conversion of fatty acids into 2-hydroperoxy derivatives with a substrate preference for α-linolenic, linoleic and palmitic acids. Ppα-DOX is expressed during development in tips of young protonemal filaments with maximum expression levels in mitotically active undifferentiated apical cells. In leafy gametophores, Ppα-DOX is expressed in auxin producing tissues, including rhizoid and axillary hairs. Ppα-DOX transcript levels and Ppα-DOX activity increased in moss tissues infected with Botrytis cinerea or treated with Pectobacterium carotovorum elicitors. In B. cinerea infected leaves, Ppα-DOX-GUS proteins accumulated in cells surrounding infected cells, suggesting a protective mechanism. Targeted disruption of Ppα-DOX did not cause a visible developmental alteration and did not compromise the defense response. However, overexpressing Ppα-DOX, or incubating wild-type tissues with Ppα-DOX-derived oxylipins, principally the aldehyde heptadecatrienal, resulted in smaller moss colonies with less protonemal tissues, due to a reduction of caulonemal filament growth and a reduction of chloronemal cell size compared with normal tissues. In addition, Ppα-DOX overexpression and treatments with Ppα-DOX-derived oxylipins reduced cellular damage caused by elicitors of P. carotovorum. CONCLUSIONS: Our study shows that the unique α-DOX of the primitive land plant P. patens, although apparently not crucial, participates both in development and in the defense response against pathogens, suggesting that α-DOXs from flowering plants could have originated by duplication and successive functional diversification after the divergence from bryophytes.


Asunto(s)
Bryopsida/enzimología , Bryopsida/genética , Dioxigenasas/genética , Dioxigenasas/metabolismo , Regulación de la Expresión Génica de las Plantas , Inmunidad de la Planta , Botrytis/fisiología , Bryopsida/crecimiento & desarrollo , Bryopsida/inmunología , Datos de Secuencia Molecular , Pectobacterium carotovorum/fisiología , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN
12.
Phys Chem Chem Phys ; 16(30): 16302-11, 2014 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-24978840

RESUMEN

Long-lived quantum coherences observed in several photosynthetic pigment-protein complexes at low and at room temperatures have generated a heated debate over the impact that the coupling of electronic excitations to molecular vibrations of the relevant actors (pigments, proteins and solvents) has on the excitation energy transfer process. In this work, we use a combined MD and QM/MMPol strategy to investigate the exciton-phonon interactions in the PE545 light-harvesting complex by computing the spectral densities for each pigment and analyzing their consequences in the exciton dynamics. Insights into the origin of relevant peaks, as well as their differences among individual pigments, are provided by correlating them with normal modes obtained from a quasi-harmonic analysis of the motions sampled by the pigments in the complex. Our results indicate that both the protein and the solvent significantly modulate the intramolecular vibrations of the pigments thus playing an important role in promoting or suppressing certain exciton-phonon interactions. We also find that these low-frequency features are largely smoothed out when the spectral density is averaged over the complex, something difficult to avoid in experiments that underscores the need to combine theory and experiment to understand the origin of quantum coherence in photosynthetic light-harvesting.


Asunto(s)
Complejos de Proteína Captadores de Luz/química , Pigmentos Biológicos/química
13.
Nutrients ; 16(13)2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38999879

RESUMEN

Place of residence (urban versus rural) is a contextual determinant of health that has received less attention in the food insecurity literature. The purpose of this study was to assess the urban-rural disparity in the prevalence of food insecurity and weight status among US children. Using data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016 with three age groups of children (2-5, 6-11, and 12-17 years old), the associations of weight status and child and household food security status by urban-rural residence were examined using Rao-Scott Chi-square tests. Statistical significance was set at p < 0.05. Children living in urban areas were significantly more likely to experience household food insecurity (29.15%) compared to their rural counterparts (19.10%), among those aged 6-11 years. The associations between children's weight status and child and household food security status were significant for children living in urban areas overall and different age groups but not for children living in rural areas. These trends were more pronounced in older age groups. Given the link between food insecurity and higher obesity rates, particularly among urban children, this study highlights the importance of incorporating food security interventions into future obesity prevention programs.


Asunto(s)
Peso Corporal , Inseguridad Alimentaria , Encuestas Nutricionales , Población Rural , Población Urbana , Humanos , Niño , Población Rural/estadística & datos numéricos , Estados Unidos/epidemiología , Masculino , Femenino , Preescolar , Población Urbana/estadística & datos numéricos , Adolescente , Obesidad Infantil/epidemiología , Disparidades en el Estado de Salud , Prevalencia , Abastecimiento de Alimentos/estadística & datos numéricos
14.
Nutrients ; 16(2)2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38257117

RESUMEN

Understanding the association between food security status (FSS) and diet quality in children is crucial. This study investigated regional variability in FSS, participation in the federal nutrition assistance program (FNAP), and diet quality among US children. National Health and Nutrition Examination Survey (NHANES) data from 2013 to 2016 were analyzed. The association between FSS, FNAP participation, and diet quality (Healthy Eating Index-HEI-2015) was assessed using multiple linear/logistic regression models. The sample included 6403 children (mean age: 7.5 years; 51% male; 33% Hispanic). Within the sample, 13% reported child food insecurity, and 30% reported household food insecurity. Additionally, 90% participated in the FNAP, and 88% were enrolled in school lunch programs. Children in urban areas were significantly more likely to report household food insecurity than those in rural areas (29.15% vs. 19.10%). The overall HEI-2015 score was 48.2. The associations between child/household FSS and FNAP participation as well as between child/household FSS and diet quality did not differ by urban/rural residence status, irrespective of the children's age groups. There is a need for improvement in children's diet quality, regardless of age or urban/rural residence. The findings suggest that improving children's diets requires broader action as well as the prioritizing of children in urban areas experiencing food insecurity in future dietary interventions.


Asunto(s)
Dieta , Inseguridad Alimentaria , Estado Nutricional , Niño , Femenino , Humanos , Masculino , Dieta/normas , Dieta/estadística & datos numéricos , Hispánicos o Latinos , Encuestas Nutricionales/estadística & datos numéricos , Prevalencia , Estados Unidos/epidemiología , Población Rural/estadística & datos numéricos , Población Urbana/estadística & datos numéricos
15.
Interv Neuroradiol ; : 15910199241258373, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38832443

RESUMEN

Medium vessel occlusions (MeVOs), defined as occlusion of the M2/M3 and A2/A3 segments of the middle cerebral artery (MCA) and anterior cerebral artery, can be challenging to visualize on CT angiography (CTA) and MR angiography (MRA), given the anatomic complexity of the mid- and distal intracranial vasculature and smaller vessel caliber (Leary MC, Kidwell CS, Villablanca JP, et al. Validation of computed tomographic MCA "dot" sign: an angiographic correlation study. Stroke 2003; 34: 2636-2640; Luijten SPR, Wolff L, Duvekot MHC, et al. Diagnostic performance of an algorithm for automated large vessel occlusion (LVO) detection on CTA. J Neurointerv Surg 2022; 14: 794-798). In turn, the appearance of a sudden vessel cutoff in these vascular distributions on CTA or MRA is not always straightforward and may represent true occlusion, variant anatomy, and/or artifact (Leary MC, Kidwell CS, Villablanca JP, et al. Validation of computed tomographic MCA "dot" sign: an angiographic correlation study. Stroke 2003; 34: 2636-2640; Luijten SPR, Wolff L, Duvekot MHC, et al. Diagnostic performance of an algorithm for automated LVO detection on CTA. J Neurointerv Surg 2022; 14: 794-798). Given the importance of rapidly establishing an accurate diagnosis in the setting of stroke, combined with recent clinical trials and movements promoting the efficacy of endovascular therapeutic approaches to treat MeVOs, it remains imperative to detect such occlusions accurately and quickly on imaging. In turn, we present five imaging patterns of the Sylvian Triangle on sagittal reformatted images from CTA Head examinations, which our practice has utilized to assess patency of the M2 and M3 divisions. This approach is rapidly deployable and can be utilized by radiology and non-radiology healthcare providers alike, thus facilitating rapid and accurate diagnosis of MeVO, timely evaluation of candidacy for endovascular therapy, and ultimately supporting favorable door-to-intervention time and successful patient outcomes.

16.
BMC Plant Biol ; 13: 174, 2013 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-24188413

RESUMEN

BACKGROUND: Plant small heat shock proteins (sHsps) accumulate in response to various environmental stresses, including heat, drought, salt and oxidative stress. Numerous studies suggest a role for these proteins in stress tolerance by preventing stress-induced protein aggregation as well as by facilitating protein refolding by other chaperones. However, in vivo evidence for the involvement of sHsps in tolerance to different stress factors is still missing, mainly due to the lack of appropriate mutants in specific sHsp genes. RESULTS: In this study we characterized the function of a sHsp in abiotic stress tolerance in the moss Physcomitrella patens, a model for primitive land plants. Using suppression subtractive hybridization, we isolated an abscisic acid-upregulated gene from P. patens encoding a 16.4 kDa cytosolic class II sHsp. PpHsp16.4 was also induced by salicylic acid, dithiothreitol (DTT) and by exposure to various stimuli, including osmotic and salt stress, but not by oxidative stress-inducing compounds. Expression of the gene was maintained upon stress relief, suggesting a role for this protein in the recovery stage. PpHsp16.4 is encoded by two identical genes arranged in tandem in the genome. Targeted disruption of both genes resulted in the inability of plants to recover from heat, salt and osmotic stress. In vivo localization studies revealed that PpHsp16.4 localized in cytosolic granules in the vicinity of chloroplasts under non stress conditions, suggesting possible distinct roles for this protein under stress and optimal growth. CONCLUSIONS: We identified a member of the class II sHsp family that showed hormonal and abiotic stress gene regulation. Induction of the gene by DTT treatment suggests that damaged proteins may act as signals for the stress-induction of PpHsp16.4. The product of this gene was shown to localize in cytosolic granules near the chloroplasts, suggesting a role for the protein in association with these organelles. Our study provides the first direct genetic evidence for a role of a sHsp in osmotic and salt stress tolerance, and supports a function for this protein particularly during the stress recovery stage of P. patens.


Asunto(s)
Bryopsida/fisiología , Calor , Presión Osmótica/efectos de los fármacos , Proteínas de Plantas/metabolismo , Cloruro de Sodio/farmacología , Estrés Fisiológico/efectos de los fármacos , Ácido Abscísico/farmacología , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Bryopsida/efectos de los fármacos , Bryopsida/genética , Gránulos Citoplasmáticos/efectos de los fármacos , Gránulos Citoplasmáticos/metabolismo , Citosol/efectos de los fármacos , Citosol/metabolismo , Eliminación de Gen , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Técnicas de Inactivación de Genes , Marcación de Gen , Genes de Plantas , Proteínas de Choque Térmico Pequeñas/genética , Proteínas de Choque Térmico Pequeñas/metabolismo , Peso Molecular , Oryza/efectos de los fármacos , Oryza/metabolismo , Filogenia , Proteínas de Plantas/genética , Factores de Tiempo
17.
Ophthalmic Plast Reconstr Surg ; 29(3): 157-9, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23503056

RESUMEN

INTRODUCTION: The objective was to describe the range of normal volumes for the lacrimal gland calculated from CT. METHODS: A retrospective review with institutional review board approval of 293 CT scans of 586 orbits was performed. Patients were included if they were Caucasian and aged 18 years or older. Orbits were excluded if there was a disease or trauma. OsiriX software was used to outline the lacrimal gland in consecutive axial slices and to calculate the volume. Inter-rater agreement was assessed in a subset of 30 randomly selected orbits by observers of different levels of training using the intraclass correlation coefficient (ICC). RESULTS: Two hundred sixty orbits of 187 patients were included. The mean volume of the lacrimal gland was 0.696 cm2 in right orbits (SD = 0.261) and 0.649 cm2 in left orbits (SD = 0.231), with no significant difference between right and left (p= 0.125). The mean volume was 0.680 cm2 in men (SD = 0.241) and 0.662 cm2 in women (SD = 0.260), with no significant difference between men and women (p = 0.564). There was an inverse relationship between gland volume and age (Pearson r= -0.428 right orbits and -0.469 left orbits). Of the 73 bilateral patients, right and left orbits correlated well (Pearson r = 0.712). Agreement was good among the observers (ICC = 0.727). CONCLUSIONS: This is the first study to report the range of normal volume for Caucasian lacrimal glands measured on CT scans. The volume of the lacrimal gland decreases with age, and there is no gender or laterality difference.


Asunto(s)
Aparato Lagrimal/anatomía & histología , Órbita/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Población Blanca , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Aparato Lagrimal/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Valores de Referencia , Estudios Retrospectivos , Adulto Joven
18.
Front Plant Sci ; 14: 1184020, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37346131

RESUMEN

Soybean is a globally important legume crop which is highly sensitive to drought. The identification of genes of particular relevance for drought responses provides an important basis to improve tolerance to environmental stress. Chloroplast Vesiculation (CV) genes have been characterized in Arabidopsis and rice as proteins participating in a specific chloroplast-degradation vesicular pathway (CVV) during natural or stress-induced leaf senescence. Soybean genome contains two paralogous genes encoding highly similar CV proteins, CV1 and CV2. In this study, we found that expression of CV1 was differentially upregulated by drought stress in soybean contrasting genotypes exhibiting slow-wilting (tolerant) or fast-wilting (sensitive) phenotypes. CV1 reached higher induction levels in fast-wilting plants, suggesting a negative correlation between CV1 gene expression and drought tolerance. In contrast, autophagy (ATG8) and ATI-PS (ATI1) genes were induced to higher levels in slow-wilting plants, supporting a pro-survival role for these genes in soybean drought tolerance responses. The biological function of soybean CVs in chloroplast degradation was confirmed by analyzing the effect of conditional overexpression of CV2-FLAG fusions on the accumulation of specific chloroplast proteins. Functional specificity of CV1 and CV2 genes was assessed by analyzing their specific promoter activities in transgenic Arabidopsis expressing GUS reporter gene driven by CV1 or CV2 promoters. CV1 promoter responded primarily to abiotic stimuli (hyperosmolarity, salinity and oxidative stress), while the promoter of CV2 was predominantly active during natural senescence. Both promoters were highly responsive to auxin but only CV1 responded to other stress-related hormones, such as ABA, salicylic acid and methyl jasmonate. Moreover, the dark-induced expression of CV2, but not of CV1, was strongly inhibited by cytokinin, indicating similarities in the regulation of CV2 to the reported expression of Arabidopsis and rice CV genes. Finally, we report the expression of both CV1 and CV2 genes in roots of soybean and transgenic Arabidopsis, suggesting a role for the encoded proteins in root plastids. Together, the results indicate differential roles for CV1 and CV2 in development and in responses to environmental stress, and point to CV1 as a potential target for gene editing to improve crop performance under stress without compromising natural development.

19.
Phys Rev Lett ; 109(25): 259701; discussion 259702, 2012 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-23368508

RESUMEN

A Comment on the Letter by A. Eisfeld et al. Phys. Rev. Lett. 105, 137402 (2010). The authors of the Letter offer a Reply.

20.
J Chem Phys ; 136(2): 024112, 2012 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-22260569

RESUMEN

We present a formalism to quantify the contribution of path-interference in phonon-mediated electronic energy transfer. The transfer rate between two molecules is computed by considering the quantum mechanical amplitudes associated with pathways connecting the initial and final sites. This includes contributions from classical pathways, but also terms arising from interference of different pathways. We treat the vibrational modes coupled to the molecules as a non-Markovian harmonic oscillator bath, and investigate the correction to transfer rates due to the lowest-order interference contribution. We show that depending on the structure of the harmonic bath, the correction due to path-interference may have a dominant vibrational or electronic character, and can make a notable contribution to the transfer rate in the steady state.


Asunto(s)
Electrones , Ficoeritrina/química , Transferencia de Energía , Teoría Cuántica
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