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1.
J Can Acad Child Adolesc Psychiatry ; 33(1): 18-32, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38449724

RESUMEN

Background: Many youth in the criminal justice system are affected by mental health and/or substance use (MHS) challenges, yet only a minority receive treatment. One way to increase access to MHS care is integrated youth services (IYS), a community-based model of service delivery where youth can access evidence-based treatment for their MHS problems and other wellbeing needs, in one location. However, it is unknown what IYS services justice-involved youth prioritize. Objective: This study explored what components of IYS justice-involved youth deem to be the most important in meeting their MHS service needs, in comparison with non-justice-involved youth, by conducting a secondary analysis of data gathered from a larger Ontario-wide study. Method: Using a conjoint analysis, n = 55 justice-involved youth, and n = 188 non-justice-involved youth, completed thirteen choice tasks representing different combinations of IYS. Results: Both justice-involved and non-justice-involved youth exhibited preferences for a broad range of core health services, including mental health services, substance misuse counseling, medication management, and physical or sexual health services. They also preferred a broad range of additional support services, in addition to fast access to care in a community setting that specializes in mental health services, with the incorporation of e-health services. Justice-involved youth prioritized working with a trained peer support worker to learn life skills and help them with the services they need. The importance of youth playing a leadership role in making decisions within IYS organizations was also a distinguishing preference among justice-involved youth. Conclusions: Tailoring IYS to meet the service preferences of justice-involved youth may enhance service utilization, potentially leading to better outcomes for justice-involved youth and their communities.


Contexte: Nombre de jeunes dans le système de justice pénale sont affectés de problèmes de santé mentale et/ou d'utilisation de substances (SMS), pourtant seule une minorité reçoit un traitement. Une façon d'élargir l'accès aux soins SMS consiste dans les services intégrés à la jeunesse (SIJ), un modèle communautaire de prestation de service dans lequel les jeunes peuvent avoir accès à un traitement fondé sur les données probantes pour leurs problèmes de SMS et autres besoins de bien-être en un seul lieu. Cependant, on ne sait pas à quels SIJ les jeunes impliqués dans la justice accordent la priorité. Objectif: La présente étude a exploré quelles composantes des SIJ sont jugées les plus importantes par les jeunes impliqués dans la justice pour répondre à leurs besoins de service de SMS, en comparaison avec les jeunes non impliqués dans la justice, au moyen d'une analyse secondaire des données recueillies d'une étude plus vaste à l'échelle de l'Ontario. Méthode: À l'aide d'une analyse conjointe, n = 55 jeunes impliqués dans la justice, et n = 188 jeunes non impliqués dans la justice ont répondu à treize tâches à choix représentant différentes combinaisons de SIJ. Résultats: Tant les jeunes impliqués dans la justice que les jeunes non impliqués ont affiché des préférences pour une large gamme de services de santé de base, notamment les services de santé mentale, la consultation pour abus de substances, la gestion des médicaments, et les services de santé physique ou sexuelle. Ils préféraient également une large gamme de services de soutien additionnels, en plus d'un accès rapide aux soins dans un milieu communautaire qui se spécialise en services de santé mentale, avec l'incorporation de services de santé en ligne. Les jeunes impliqués dans la justice accordaient la priorité au travail avec un pair aidant formé pour apprendre les compétences de la vie et les aider dans les services dont ils ont besoin. L'importance pour les jeunes de jouer un rôle de leadership dans la prise de décisions au sein des organisations de SIJ était également une préférence distincte chez les jeunes impliqués dans la justice. Conclusions: Adapter les SIJ pour répondre aux préférences de services des jeunes impliqués dans la justice peut améliorer l'utilisation des services, et mener potentiellement à de meilleurs résultats pour les jeunes impliqués dans la justice et leurs communautés.

2.
Int J Integr Care ; 24(1): 2, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38312478

RESUMEN

Introduction: Mental health and/or substance use (MHS) challenges affect approximately 95% of youth in the criminal justice system, with only three in ten justice-involved youth receiving treatment. Caregivers of justice-involved youth have identified fragmented care as a barrier to youth accessing MHS services. One suggested solution to this problem is the implementation of integrated youth services (IYS). However, it is unknown which IYS components caregivers of justice-involved youth prioritize. Methods: Using a discrete choice conjoint experiment (DCE), n = 46 caregivers of justice-involved youth, and n = 204 caregivers of non-justice-involved, completed thirteen choice tasks representing different combinations of IYS. Results: Both caregiver groups exhibited preferences for involvement and access to information regarding their youth's treatment, and fast access to broad range of core health and additional services, in a community setting, with the incorporation of e-health services. Caregivers of justice-involved youth showed a unique preference for involvement in family counseling with their youth. The incorporation of this service feature may help to engage caregivers of justice-involved youth in their youths' MHS treatment 3-fold. Conclusion: Data gleaned from this analysis provides an understanding of what components of IYS models may help to engage caregivers of justice-involved youth.

3.
PLoS One ; 19(2): e0297666, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38377053

RESUMEN

Male contraceptive options and infertility treatments are limited, and almost all innovation has been limited to updates to medically assisted reproduction protocols and methods. To accelerate the development of drugs that can either improve or inhibit fertility, we established a small molecule library as a toolbox for assay development and screening campaigns using human spermatozoa. We have profiled all compounds in the Sperm Toolbox in several automated high-throughput assays that measure stimulation or inhibition of sperm motility or the acrosome reaction. We have assayed motility under non-capacitating and capacitating conditions to distinguish between pathways operating under these different physiological states. We also assayed cell viability to ensure any effects on sperm function are specific. A key advantage of our studies is that all compounds are assayed together in the same experimental conditions, which allows quantitative comparisons of their effects in complementary functional assays. We have combined the resulting datasets to generate fingerprints of the Sperm Toolbox compounds on sperm function. The data are included in an on-line R-based app for convenient querying.


Asunto(s)
Semen , Motilidad Espermática , Humanos , Masculino , Espermatozoides/metabolismo , Reacción Acrosómica , Fertilidad
4.
J Clin Neurosci ; 114: 64-69, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37321019

RESUMEN

BACKGROUND: Deep-seated intracranial lesions can be accessed using blade retractors that may disrupt white matter tracts, exert pressure on adjacent tissue, and lead to post-operative venous injury. Tubular retractors may minimize disruption to white matter tracts by radially dispersing pressure onto surrounding tissue. This study characterizes perioperative outcomes in patients undergoing biopsy or resection of intracranial pathologies using tubular retractors. METHODS: Adult patients (≥18 years) undergoing neurosurgical intervention using tubular retractors at a single health system (January 2016-February 2022) were identified through chart review. Demographics, disease characteristics, management data, and clinical outcomes were collected. RESULTS: A total of 49 patients were included; 23 (47%) had primary brain tumors, 8 (16%) metastases, 6 (12%) intracranial hemorrhage (ICH), 5 (10%) cavernomas, and 7 (14%) other pathologies. Lesions were located subcortically (n = 19, 39%), intraventricularly (n = 15, 31%), and in deep gray matter (n = 11, 22%). Gross total resection (GTR) or near GTR was achieved in 21 of 26 (80.8%) patients with intracranial lesions where GTR was the goal of surgery; 10 of 11 (90.9%) biopsies in patients with masses were diagnostic. Five of six (83.3%) ICHs were totally or near totally evacuated. Seventeen patients (35%) had major complications post-operatively. The most common complications were DVT/PE (n = 7, 14%) and seizures (n = 6, 12%). For patients who experienced post-operative seizures, 3 had seizures preoperatively and 1 had seizures in the context of electrolyte derangements. No patients died of post-operative complications. CONCLUSION: This operative approach may facilitate safe and efficacious biopsy or resection of deep-seated intracranial pathologies.


Asunto(s)
Neoplasias Encefálicas , Adulto , Humanos , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/cirugía , Procedimientos Neuroquirúrgicos , Microcirugia , Convulsiones/cirugía , Encéfalo/cirugía , Procedimientos Quirúrgicos Mínimamente Invasivos
5.
Front Plant Sci ; 13: 876843, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36466234

RESUMEN

Stress-responsive components of the mitochondrial alternative electron transport pathway have the capacity to improve tolerance of plants to abiotic stress, particularly the alternative oxidase AOX1A but also external NAD(P)H dehydrogenases such as NDB2, in Arabidopsis. NDB2 and AOX1A can cooperate to entirely circumvent the classical electron transport chain in Arabidopsis mitochondria. Overexpression of AOX1A or NDB2 alone can have slightly negative impacts on plant growth under optimal conditions, while simultaneous overexpression of NDB2 and AOX1A can reverse these phenotypic effects. We have taken a global transcriptomic approach to better understand the molecular shifts that occur due to overexpression of AOX1A alone and with concomitant overexpression of NDB2. Of the transcripts that were significantly up- or down- regulated in the AOX1A overexpression line compared to wild type (410 and 408, respectively), the majority (372 and 337, respectively) reverted to wild type levels in the dual overexpression line. Several mechanisms for the AOX1A overexpression phenotype are proposed based on the functional classification of these 709 genes, which can be used to guide future experiments. Only 28 genes were uniquely up- or down-regulated when NDB2 was overexpressed in the AOX1A overexpression line. On the other hand, many unique genes were deregulated in the NDB2 knockout line. Furthermore, several changes in transcript abundance seen in the NDB2 knockout line were consistent with changes in the AOX1A overexpression line. The results suggest that an imbalance in AOX1A:NDB2 protein levels caused by under- or over-expression of either component, triggers a common set of transcriptional responses that may be important in mitochondrial redox regulation. The most significant changes were transcripts associated with photosynthesis, secondary metabolism and oxidative stress responses.

6.
J Neurooncol ; 159(2): 233-242, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35913556

RESUMEN

INTRODUCTION: Supratotal resection (SpTR) of glioblastoma may be associated with improved survival, but published results have varied in part from lack of consensus on the definition and appropriate use of SpTR. A previous small survey of neurosurgical oncologists with expertise performing SpTR found resection 1-2 cm beyond contrast enhancement was an acceptable definition and glioblastoma involving the right frontal and bilateral anterior temporal lobes were considered most amenable to SpTR. The general neurosurgical oncology community has not yet confirmed the practicality of this definition. METHODS: Seventy-six neurosurgical oncology members of the AANS/CNS Tumor Section were surveyed, representing 34.0% of the 223 members who were administered the survey. Participants were presented with 11 definitions of SpTR and rated each definition's appropriateness. Participants additionally reviewed magnetic resonance imaging for 10 anatomically distinct glioblastomas and assessed the tumor location's eloquence, perceived equipoise of enrolling patients in a randomized trial comparing gross total to SpTR, and their personal treatment plans. RESULTS: Most neurosurgeons surveyed agree that gross total plus resection of some non-contrast enhancement (n = 57, 80.3%) or resection 1-2 cm beyond contrast enhancement (n = 52, 73.2%) are appropriate definitions for SpTR. Cases were divided into three anatomically distinct groups by perceived equipoise between gross total and SpTR. The best clinical trial candidates were thought to be right anterior temporal (n = 58, 76.3%) and right frontal (n = 55, 73.3%) glioblastomas. CONCLUSION: Support exists among neurosurgical oncologists with varying familiarity performing SpTR to adopt the proposed consensus definition of SpTR of glioblastoma and to potentially investigate the utility of SpTR to treat right anterior temporal and right frontal glioblastomas in a clinical trial. A smaller proportion of general neurosurgical oncologists than SpTR experts would personally treat a left anterior temporal glioblastoma with SpTR.


Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Oncólogos , Neoplasias Encefálicas/cirugía , Consenso , Glioblastoma/cirugía , Humanos , Neurocirugia , Ensayos Clínicos Controlados Aleatorios como Asunto , Encuestas y Cuestionarios
7.
Plant Cell Environ ; 45(4): 1257-1269, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35048399

RESUMEN

Our understanding of the regulation of respiration in C4 plants, where mitochondria play different roles in the different types of C4 photosynthetic pathway, remains limited. We examined how leaf dark respiration rates (Rdark ), in the presence and absence of added malate, vary in monocots representing the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK) using intact leaves and extracted bundle sheath strands. In particular, we explored to what extent rates of Rdark are associated with mitochondrial number, volume and ultrastructure. Based on examination of a single species per C4 type, we found that the respiratory response of NAD-ME and PCK type bundle sheath strands to added malate was associated with differences in mitochondrial number, volume, and/or ultrastructure, while NADP-ME type bundle sheath strands did not respond to malate addition. In general, mitochondrial traits reflected the contributions mitochondria make to photosynthesis in the three C4 types. However, despite the obvious differences in mitochondrial traits, no clear correlation was observed between these traits and Rdark . We suggest that Rdark is primarily driven by cellular maintenance demands and not mitochondrial composition per se, in a manner that is somewhat independent of mitochondrial organic acid cycling in the light.


Asunto(s)
Malato Deshidrogenasa , Malatos , Malato Deshidrogenasa/metabolismo , Malatos/metabolismo , Mitocondrias/metabolismo , NAD/metabolismo , NADP/metabolismo , Fotosíntesis , Hojas de la Planta/metabolismo , Frecuencia Respiratoria
8.
New Phytol ; 233(3): 1083-1096, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34669188

RESUMEN

C4 photosynthesis involves a series of biochemical and anatomical traits that significantly improve plant productivity under conditions that reduce the efficiency of C3 photosynthesis. We explore how evolution of the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK types) has affected the functions and properties of mitochondria. Mitochondria in C4 NAD-ME and PCK types play a direct role in decarboxylation of metabolites for C4 photosynthesis. Mitochondria in C4 PCK type also provide ATP for C4 metabolism, although this role for ATP provision is not seen in NAD-ME type. Such involvement has increased mitochondrial abundance/size and associated enzymatic capacity, led to changes in mitochondrial location and ultrastructure, and altered the role of mitochondria in cellular carbon metabolism in the NAD-ME and PCK types. By contrast, these changes in mitochondrial properties are absent in the C4 NADP-ME type and C3 leaves, where mitochondria play no direct role in photosynthesis. From an eco-physiological perspective, rates of leaf respiration in darkness vary considerably among C4 species but does not differ systematically among the three C4 types. This review outlines further mitochondrial research in key areas central to the engineering of the C4 pathway into C3 plants and to the understanding of variation in rates of C4 dark respiration.


Asunto(s)
Malato Deshidrogenasa , Fotosíntesis , Dióxido de Carbono/metabolismo , Malato Deshidrogenasa/metabolismo , Mitocondrias/metabolismo , Hojas de la Planta/fisiología
9.
Molecules ; 26(22)2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34833968

RESUMEN

Legumes form a symbiosis with rhizobia, a soil bacterium that allows them to access atmospheric nitrogen and deliver it to the plant for growth. Biological nitrogen fixation occurs in specialized organs, termed nodules, that develop on the legume root system and house nitrogen-fixing rhizobial bacteroids in organelle-like structures termed symbiosomes. The process is highly energetic and there is a large demand for carbon by the bacteroids. This carbon is supplied to the nodule as sucrose, which is broken down in nodule cells to organic acids, principally malate, that can then be assimilated by bacteroids. Sucrose may move through apoplastic and/or symplastic routes to the uninfected cells of the nodule or be directly metabolised at the site of import within the vascular parenchyma cells. Malate must be transported to the infected cells and then across the symbiosome membrane, where it is taken up by bacteroids through a well-characterized dct system. The dicarboxylate transporters on the infected cell and symbiosome membranes have been functionally characterized but remain unidentified. Proteomic and transcriptomic studies have revealed numerous candidates, but more work is required to characterize their function and localise the proteins in planta. GABA, which is present at high concentrations in nodules, may play a regulatory role, but this remains to be explored.


Asunto(s)
Fabaceae/metabolismo , Malatos/metabolismo , Fijación del Nitrógeno , Nódulos de las Raíces de las Plantas/metabolismo , Transporte Biológico , Rhizobiaceae/metabolismo , Simbiosis
10.
J Org Chem ; 86(17): 12427-12435, 2021 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-34424699

RESUMEN

The work reported herein showcases a new route to access α-fluoro-α-triazol-1-yl ketones from sulfoxonium ylides via α-azido-α-fluoro ketone intermediates. In a one-pot, two-step sequence, the ketosulfoxonium reactant initially undergoes insertion of F+ and N3-, followed by a subsequent CuAAC reaction with arylacetylenes to install a 1,4-triazolo moiety. The approach allows for modification to both the sulfoxonium ylide and arylacetylene reactants. Fifteen examples have been reported, with yields ranging between 22% and 75%.


Asunto(s)
Cetonas
11.
Chem Rec ; 21(10): 2837-2854, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33533538

RESUMEN

The importance of gem-difunctionalized ketones is represented by their broad applications across chemical boundaries over recent years. The interesting reactivities that this class of compounds possess have made them ideal building blocks to access high-value organic molecules. Furthermore, the gem-difunctionalized ketone moiety has featured in numerous bioactive molecules. For these reasons, a plethora of routes to access such significant molecules have been developed by research groups worldwide - this account looks at delineating the synthesis of gem-difunctionalized ketones from carbonyl substrates, diazo compounds, sulfur ylides and alkynyl reactants.

12.
Plant Physiol ; 186(1): 581-598, 2021 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-33619553

RESUMEN

Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N2) to ammonia and provide it to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia that are enclosed in a plant-derived symbiosome membrane (SM) to form an organelle-like structure called the symbiosome. In mature nodules exchanges between the symbionts occur across the SM. Here we characterize Yellow Stripe-like 7 (GmYSL7), a Yellow stripe-like family member localized on the SM in soybean (Glycine max) nodules. It is expressed specifically in infected cells with expression peaking soon after nitrogenase becomes active. Unlike most YSL family members, GmYSL7 does not transport metals complexed with phytosiderophores. Rather, it transports oligopeptides of between four and 12 amino acids. Silencing GmYSL7 reduces nitrogenase activity and blocks infected cell development so that symbiosomes contain only a single bacteroid. This indicates the substrate of YSL7 is required for proper nodule development, either by promoting symbiosome development directly or by preventing inhibition of development by the plant. RNAseq of nodules where GmYSL7 was silenced suggests that the plant initiates a defense response against rhizobia with genes encoding proteins involved in amino acid export downregulated and some transcripts associated with metal homeostasis altered. These changes may result from the decrease in nitrogen fixation upon GmYSL7 silencing and suggest that the peptide(s) transported by GmYSL7 monitor the functional state of the bacteroids and regulate nodule metabolism and transport processes accordingly. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role.


Asunto(s)
Glycine max/genética , Proteínas de Transporte de Membrana/genética , Fijación del Nitrógeno , Proteínas de Plantas/genética , Rhizobium/fisiología , Transporte Biológico , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Plantas/metabolismo , Glycine max/metabolismo , Glycine max/microbiología , Simbiosis
13.
Int J Mol Sci ; 22(1)2021 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-33406726

RESUMEN

Iron is an essential nutrient for the legume-rhizobia symbiosis and nitrogen-fixing bacteroids within root nodules of legumes have a very high demand for the metal. Within the infected cells of nodules, the bacteroids are surrounded by a plant membrane to form an organelle-like structure called the symbiosome. In this review, we focus on how iron is transported across the symbiosome membrane and accessed by the bacteroids.


Asunto(s)
Bacteroides/fisiología , Fabaceae/metabolismo , Hierro/metabolismo , Nitrógeno/metabolismo , Orgánulos/metabolismo , Proteínas de Plantas/metabolismo , Simbiosis , Transporte Biológico , Fabaceae/microbiología , Fijación del Nitrógeno , Orgánulos/microbiología , Nódulos de las Raíces de las Plantas/metabolismo , Nódulos de las Raíces de las Plantas/microbiología
14.
Front Plant Sci ; 12: 813691, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35111186

RESUMEN

Alternative oxidase (AOX) is an important component of the plant respiratory pathway, enabling a route for electrons that bypasses the energy-conserving, ROS-producing complexes of the mitochondrial electron transport chain. Plants contain numerous isoforms of AOX, classified as either AOX1 or AOX2. AOX1 isoforms have received the most attention due to their importance in stress responses across a wide range of species. However, the propensity for at least one isoform of AOX2 to accumulate to very high levels in photosynthetic tissues of all legumes studied to date, suggests that this isoform has specialized roles, but we know little of its properties. Previous studies with sub-mitochondrial particles of soybean cotyledons and roots indicated that differential expression of GmAOX1, GmAOX2A, and GmAOX2D across tissues might confer different activation kinetics with pyruvate. We have investigated this using recombinantly expressed isoforms of soybean AOX in a previously described bacterial system (Selinski et al., 2016, Physiologia Plantarum 157, 264-279). Pyruvate activation kinetics were similar between the two GmAOX2 isoforms but differed substantially from those of GmAOX1, suggesting that selective expression of AOX1 and 2 could determine the level of AOX activity. However, this alone cannot completely explain the differences seen in sub-mitochondrial particles isolated from different legume tissues and possible reasons for this are discussed.

15.
BMC Plant Biol ; 20(Suppl 1): 183, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-33050887

RESUMEN

BACKGROUND: Chickpea is an important legume and is moderately tolerant to salinity stress during the growing season. However, the level and mechanisms for salinity tolerance can vary among accessions and cultivars. A large family of CaRab-GTP genes, previously identified in chickpea, is homologous to intracellular vesicle trafficking superfamily genes that play essential roles in response to salinity stress in plants. RESULTS: To determine which of the gene family members are involved in the chickpea salt response, plants from six selected chickpea accessions (Genesis 836, Hattrick, ICC12726, Rupali, Slasher and Yubileiny) were exposed to salinity stress and expression profiles resolved for the major CaRab-GTP gene clades after 5, 9 and 15 days of salt exposure. Gene clade expression profiles (using degenerate primers targeting all members of each clade) were tested for their relationship to salinity tolerance measures, namely plant biomass and Na+ accumulation. Transcripts representing 11 out of the 13 CaRab clades could be detected by RT-PCR, but only six (CaRabA2, -B, -C, -D, -E and -H) could be quantified using qRT-PCR due to low expression levels or poor amplification efficiency of the degenerate primers for clades containing several gene members. Expression profiles of three gene clades, CaRabB, -D and -E, were very similar across all six chickpea accessions, showing a strongly coordinated network. Salt-induced enhancement of CaRabA2 expression at 15 days showed a very strong positive correlation (R2 = 0.905) with Na+ accumulation in leaves. However, salinity tolerance estimated as relative plant biomass production compared to controls, did not correlate with Na+ accumulation in leaves, nor with expression profiles of any of the investigated CaRab-GTP genes. CONCLUSION: A coordinated network of CaRab-GTP genes, which are likely involved in intracellular trafficking, are important for the salinity stress response of chickpea plants.


Asunto(s)
Cicer/genética , Cicer/metabolismo , Hojas de la Planta/metabolismo , Cloruro de Sodio/farmacología , Sodio/metabolismo , Proteínas de Unión al GTP rab/metabolismo , Vesículas Citoplasmáticas/metabolismo , Perfilación de la Expresión Génica , Genes de Plantas , Potasio/metabolismo , Tolerancia a la Sal/genética
16.
Front Psychol ; 11: 1816, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32849071

RESUMEN

We propose that distinct leadership competencies differ in their development over time. Extending the integrative model of leader development (Day et al., 2009), we further propose that leader identity will form complex relationships with leadership competencies over time. To test these propositions, we use longitudinal data (i.e., 5 months, four measurement points) of the 80 in total high-potential executives in a corporate leadership development program. We find a significant difference in the initial levels and the changes of eight distinct leadership competencies. We also find that leader identity relates to the development of certain - but not all - leadership competencies. Finally, we demonstrate the importance of developing leadership competencies by linking them to career advancement (i.e., job promotion). These findings are discussed in light of their theoretical and practical implications.

17.
Int J Mol Sci ; 21(11)2020 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-32481694

RESUMEN

All plants contain an alternative electron transport pathway (AP) in their mitochondria, consisting of the alternative oxidase (AOX) and type 2 NAD(P)H dehydrogenase (ND) families, that are thought to play a role in controlling oxidative stress responses at the cellular level. These alternative electron transport components have been extensively studied in plants like Arabidopsis and stress inducible isoforms identified, but we know very little about them in the important crop plant chickpea. Here we identify AP components in chickpea (Cicer arietinum) and explore their response to stress at the transcript level. Based on sequence similarity with the functionally characterized proteins of Arabidopsis thaliana, five putative internal (matrix)-facing NAD(P)H dehydrogenases (CaNDA1-4 and CaNDC1) and four putative external (inter-membrane space)-facing NAD(P)H dehydrogenases (CaNDB1-4) were identified in chickpea. The corresponding activities were demonstrated for the first time in purified mitochondria of chickpea leaves and roots. Oxidation of matrix NADH generated from malate or glycine in the presence of the Complex I inhibitor rotenone was high compared to other plant species, as was oxidation of exogenous NAD(P)H. In leaf mitochondria, external NADH oxidation was stimulated by exogenous calcium and external NADPH oxidation was essentially calcium dependent. However, in roots these activities were low and largely calcium independent. A salinity experiment with six chickpea cultivars was used to identify salt-responsive alternative oxidase and NAD(P)H dehydrogenase gene transcripts in leaves from a three-point time series. An analysis of the Na:K ratio and Na content separated these cultivars into high and low Na accumulators. In the high Na accumulators, there was a significant up-regulation of CaAOX1, CaNDB2, CaNDB4, CaNDA3 and CaNDC1 in leaf tissue under long term stress, suggesting the formation of a stress-modified form of the mitochondrial electron transport chain (mETC) in leaves of these cultivars. In particular, stress-induced expression of the CaNDB2 gene showed a striking positive correlation with that of CaAOX1 across all genotypes and time points. The coordinated salinity-induced up-regulation of CaAOX1 and CaNDB2 suggests that the mitochondrial alternative pathway of respiration is an important facet of the stress response in chickpea, in high Na accumulators in particular, despite high capacities for both of these activities in leaf mitochondria of non-stressed chickpeas.


Asunto(s)
Cicer/genética , Cicer/fisiología , Mitocondrias/metabolismo , Proteínas Mitocondriales/genética , Oxidorreductasas/genética , Proteínas de Plantas/genética , Estrés Salino , Calcio/metabolismo , Transporte de Electrón , Regulación Enzimológica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , NADPH Deshidrogenasa/metabolismo , Oxígeno/metabolismo , Fotosíntesis , Raíces de Plantas/metabolismo , Brotes de la Planta/metabolismo , Sodio/química , Especificidad de la Especie , Transcriptoma
18.
New Phytol ; 228(2): 667-681, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32533710

RESUMEN

Legumes establish symbiotic relationships with soil bacteria (rhizobia), housed in nodules on roots. The plant supplies carbon substrates and other nutrients to the bacteria in exchange for fixed nitrogen. The exchange occurs across a plant-derived symbiosome membrane (SM), which encloses rhizobia to form a symbiosome. Iron supplied by the plant is crucial for rhizobial enzyme nitrogenase that catalyses nitrogen fixation, but the SM iron transporter has not been identified. We use yeast complementation, real-time PCR and proteomics to study putative soybean (Glycine max) iron transporters GmVTL1a and GmVTL1b and have characterized the role of GmVTL1a using complementation in plant mutants, hairy root transformation and microscopy. GmVTL1a and GmVTL1b are members of the vacuolar iron transporter family and homologous to Lotus japonicus SEN1 (LjSEN1), which is essential for nitrogen fixation. GmVTL1a expression is enhanced in nodule infected cells and both proteins are localized to the SM. GmVTL1a transports iron in yeast and restores nitrogen fixation when expressed in the Ljsen1 mutant. Three GmVTL1a amino acid substitutions that block nitrogen fixation in Ljsen1 plants reduce iron transport in yeast. We conclude GmVTL1a is responsible for transport of iron across the SM to bacteroids and plays a crucial role in the nitrogen-fixing symbiosis.


Asunto(s)
Glycine max , Fijación del Nitrógeno , Hierro , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nódulos de las Raíces de las Plantas/metabolismo , Glycine max/genética , Glycine max/metabolismo , Simbiosis
19.
Org Lett ; 22(6): 2339-2343, 2020 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-32133862

RESUMEN

The catalytic protonation of aryl diazoacetates by strong Brønsted acids, followed by a Friedel-Crafts alkylation reaction with electron rich aromatic compounds, is reported. The reaction provided in a direct fashion 24 geminal diarylacetates in yields of ≤92%.

20.
New Phytol ; 225(3): 1072-1090, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31004496

RESUMEN

Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H+ -ATPase also is a critical component. One proposed leak, that of Na+ influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na+ and Cl- concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components.


Asunto(s)
Productos Agrícolas/fisiología , Metabolismo Energético , Tolerancia a la Sal/fisiología , Transporte Biológico , Respiración de la Célula , Raíces de Plantas/anatomía & histología
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