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In December 2022, the death of Christopher Clunis was made public. He had actually died in February 2021. Christopher Clunis was convicted of the manslaughter of a stranger, Jonathan Zito. He attacked Mr Zito at a train station. This paper will argue that this terrible event became a totemic symbol of the wider failings of the policy of community care. The image of Clunis being driven away from Court was repeatedly used in newspaper and other media reports as a reference point. The image reflects a number of long-standing traits in the representation of the "mentally ill." These are combined with a racial stereotype of Black men. The paper examines historical representations of the mentally ill as a context for a discussion of the Clunis case. The paper uses the work of Stuart Hall as an analytical tool to examine the questions of race and representation, and the moral panic following failings of community care.
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Ionising radiation (IR) is a cause of lipid peroxidation, and epidemiological data have revealed a correlation between exposure to IR and the development of eye lens cataracts. Cataracts remain the leading cause of blindness around the world. The plasma membranes of lens fibre cells are one of the most cholesterolrich membranes in the human body, forming lipid rafts and contributing to the biophysical properties of lens fibre plasma membrane. Liquid chromatography followed by mass spectrometry was used to analyse bovine eye lens lipid membrane fractions after exposure to 5 and 50 Gy and eye lenses taken from wholebody 2 Gy-irradiated mice. Although cholesterol levels do not change significantly, IR dose-dependant formation of the oxysterols 7ß-hydroxycholesterol, 7-ketocholesterol and 5, 6-epoxycholesterol in bovine lens nucleus membrane extracts was observed. Whole-body X-ray exposure (2 Gy) of 12-week old mice resulted in an increase in 7ß-hydroxycholesterol and 7-ketocholesterol in their eye lenses. Their increase regressed over 24 h in the living lens cortex after IR exposure. This study also demonstrated that the IR-induced fold increase in oxysterols was greater in the mouse lens cortex than the nucleus. Further work is required to elucidate the mechanistic link(s) between oxysterols and IR-induced cataract, but these data evidence for the first time that IR exposure of mice results in oxysterol formation in their eye lenses.
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OBJECTIVE: Many studies have identified factors associated with increased symptom burden and prolonged recovery after pediatric and adolescent concussion. Few have systematically examined the effects of prior concussion on these outcomes in patients with concussion due to any mechanism. An improved understanding of the short- and long-term effects of a multiple concussion history will improve counseling and management of this subgroup of patients. METHODS: A retrospective review of adolescent and young adult acute concussion patients presenting to the multidisciplinary concussion clinic between 2018 and 2019 was conducted at a single center. Patient demographic data, medical history including prior concussion, initial symptom severity score (SSS), injury mechanisms, and recovery times were collected. Univariate and multivariable analyses were conducted to identify associations of history of prior concussion and patient and injury characteristics with symptom score and recovery time. RESULTS: A total of 266 patients with an average age of 15.4 years (age range 13-27 years) were included. Prior concussion was reported in 35% of patients. The number of prior concussions per patient was not significantly associated with presenting symptom severity, recovery time, or recovery within 28 days. Male sex and sports-related concussion (SRC) were associated with lower presenting SSS and shorter recovery time on univariate but not multivariable analysis. However, compared to non-sport concussion mechanisms, SRC was associated with 2.3 times higher odds of recovery within 28 days (p = 0.04). A history of psychiatric disorders was associated with higher SSS in univariate analysis and longer recovery time in univariate and multivariable analyses. Multivariable log-linear regression also demonstrated 5 times lower odds of recovery within 28 days for those with a psychiatric history. CONCLUSIONS: The results of this study demonstrated that an increasing number of prior concussions was associated with a trend toward higher presenting SSS after youth acute concussion but did not show a significant association with recovery time or delayed (> 28 days) recovery. Presence of psychiatric history was found to be significantly associated with longer recovery and lower odds of early (≤ 28 days) recovery. Future prospective, long-term, and systematic study is necessary to determine the optimal counseling and management of adolescent and young adult patients with a history of multiple concussions.
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The objective of this study was to investigate predictors of concussion recovery in children (5-12) versus adolescents (13-18) while identifying economic and demographic disparities in post-concussion care at a tertiary referral concussion clinic versus emergency department (ED). Race and insurance status were recorded for patients presenting to the concussion clinic (724) and ED (1,160) with an ICD-10 concussion diagnosis between 2018 and 2019. Secondly, a subset of patients from the concussion clinic group were included for retrospective cohort review based on documented recovery data. Overall, the concussion clinic saw more Caucasian patients (66.7%) than the ED (56.8%). Concussion clinic patients were more likely to have Private insurance than ED patients (67.2% vs. 55.3%) and less likely to have Medicaid and Self pay (p < 0.001). Children were more likely to be hospitalized after concussion diagnosis than adolescents (40.8% vs. 24.4%, p = 0.006). Attending public school was associated with a 1.8 times greater hazard ratio (HR) for shorter time to recovery compared to attending private school. Additionally, presence of a diagnosed psychiatric disorder was associated with a HR of 0.5, indicating a longer time to recovery (p < 0.001) than patients without a disorder. The present findings may support limitations on contact sports participation in young children given their higher hospitalization rate after concussion. Additionally, the study highlights potential barriers to care amongst youth concussion patients with those seen in specialized concussion clinics more likely to be White and have private insurance.
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Traumatismos en Atletas , Conmoción Encefálica , Adolescente , Traumatismos en Atletas/complicaciones , Traumatismos en Atletas/diagnóstico , Traumatismos en Atletas/epidemiología , Conmoción Encefálica/diagnóstico , Conmoción Encefálica/epidemiología , Conmoción Encefálica/terapia , Niño , Preescolar , Demografía , Servicio de Urgencia en Hospital , Humanos , Estudios Retrospectivos , Factores SocioeconómicosRESUMEN
This paper presents a comparative analysis of two reports by the UN Rapporteur on Extreme Poverty and Human Rights, one for Spain and one for the UK. In both countries, austerity policies were introduced following the banking crisis of 2008. The UN Rapporteur reports highlight the damage that was done by welfare retrenchment. In particular, the reports document the impact of austerity on the most vulnerable individuals and communities. The paper uses Somers' (2008) conceptual model of citizenship as the basis for a comparative analysis of two reports. Somers' (2008) model of citizenship is a triadic one which sees the state, market and civil society as competing elements. Each one can serve to regulate and limit the influence or excesses of the other two. Somers argues that neoliberalism has seen the dominance of the market at the expense of the role of the state and the institutions of civil society. Austerity policies saw the market dominating. Having examined the context of the two reports and their conclusions, the paper discussed the implications for individual social workers' practice and the role of social work as a profession in tackling poverty and marginalisation.
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The evolution and growth of multiple-herbicide resistance (MHR) in grass weeds continues to threaten global cereal production. While various processes can contribute to resistance, earlier work has identified the phi class glutathione-S-transferase (AmGSTF1) as a functional biomarker of MHR in black-grass (Alopecurus myosuroides). This study provides further insights into the role of AmGSTF1 in MHR using a combination of chemical and structural biology. Crystal structures of wild-type AmGSTF1, together with two specifically designed variants that allowed the co-crystal structure determination with glutathione and a glutathione adduct of the AmGSTF1 inhibitor 4-chloro-7-nitro-benzofurazan (NBD-Cl) were obtained. These studies demonstrated that the inhibitory activity of NBD-Cl was associated with the occlusion of the active site and the impediment of substrate binding. A search for other selective inhibitors of AmGSTF1, using ligand-fishing experiments, identified a number of flavonoids as potential ligands. Subsequent experiments using black-grass extracts discovered a specific flavonoid as a natural ligand of the recombinant enzyme. A series of related synthetic flavonoids was prepared and their binding to AmGSTF1 was investigated showing a high affinity for derivatives bearing a O-5-decyl-α-carboxylate. Molecular modelling based on high-resolution crystal structures allowed a binding pose to be defined which explained flavonoid binding specificity. Crucially, high binding affinity was linked to a reversal of the herbicide resistance phenotype in MHR black-grass. Collectively, these results present a nature-inspired new lead for the development of herbicide synergists to counteract MHR in weeds.
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Resistencia a los HerbicidasRESUMEN
When exposed to drought stress many plants reprogram their gene expression to activate adaptive biochemical and physiological responses for survival. However, most of the well-studied adaptive responses are common between drought-sensitive and drought-tolerant species, making it difficult to identify the key mechanisms underpinning successful drought tolerance in crops. We developed a sorghum experimental system that compares between drought-sensitive (ICSB338) and enhanced drought-tolerant (SA1441) varieties. We show that sorghum activates a swift and robust stomatal shutdown to preserve leaf water content when water stress has been sensed. Water uptake is enhanced via increasing root cell water potential through the rapid biosynthesis of predominantly glycine betaine and an increased root-to-shoot ratio to explore more soil volume for water. In addition to stomatal responses, there is a prompt accumulation of proline in leaves and effective protection of chlorophyll during periods of water limitation. Root and stomatal functions rapidly recover from water limitation (within 24 h of re-watering) in the drought-tolerant variety, but recovery is impaired in the drought-sensitive sorghum variety. Analysis of the root proteome revealed complex protein networks that possibly underpin sorghum responses to water limitation. Common and unique protein changes between the two sorghum varieties provide new targets for future use in investigating sorghum drought tolerance.
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Adaptación Fisiológica/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Raíces de Plantas/genética , Proteoma/genética , Sorghum/genética , Estrés Fisiológico , Betaína/metabolismo , Sequías , Ontología de Genes , Anotación de Secuencia Molecular , Osmorregulación/genética , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Proteínas de Plantas/clasificación , Proteínas de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Estomas de Plantas/fisiología , Prolina/biosíntesis , Proteoma/metabolismo , Sorghum/crecimiento & desarrollo , Sorghum/metabolismo , Agua/metabolismoRESUMEN
Forward genetic screens play a key role in the identification of genes contributing to plant stress tolerance. Using a screen for freezing sensitivity, we have identified a novel freezing tolerance gene, SENSITIVE-TO-FREEZING8, in Arabidopsis thaliana. We identified SFR8 using recombination-based mapping and whole-genome sequencing. As SFR8 was predicted to have an effect on cell wall composition, we used GC-MS and polyacrylamide gel electrophoresis to measure cell-wall fucose and boron (B)-dependent dimerization of the cell-wall pectic domain rhamnogalacturonan II (RGII) in planta. After treatments to promote borate-bridging of RGII, we assessed freeze-induced damage in wild-type and sfr8 plants by measuring electrolyte leakage from freeze-thawed leaf discs. We mapped the sfr8 mutation to MUR1, a gene encoding the fucose biosynthetic enzyme GDP-d-mannose-4,6-dehydratase. sfr8 cell walls exhibited low cell-wall fucose levels and reduced RGII bridging. Freezing sensitivity of sfr8 mutants was ameliorated by B supplementation, which can restore RGII dimerization. B transport mutants with reduced RGII dimerization were also freezing-sensitive. Our research identifies a role for the structure and composition of the plant primary cell wall in determining basal plant freezing tolerance and highlights the specific importance of fucosylation, most likely through its effect on the ability of RGII pectin to dimerize.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Pared Celular/metabolismo , Arabidopsis/citología , Proteínas de Arabidopsis/genética , Boro/metabolismo , Clonación Molecular , Congelación , Fucosa/metabolismo , Mutación , Pectinas/química , Pectinas/metabolismo , Células Vegetales/metabolismo , Estrés Fisiológico/fisiologíaRESUMEN
To conserve freshwater resources, domestic and industrial wastewater is recycled. Algal systems have emerged as an efficient, low-cost option for treatment (phycoremediation) of nutrient-rich wastewater and environmental protection. However, industrial wastewater may contain growth inhibitory compounds precluding algal use in phycoremediation. Therefore, extremophyte strains, which thrive in hostile environments, are sought-after. Here, we isolated such an alga - a strain of Synechocystis sp. we found to be capable of switching from commensal exploitation of the nitrogen-fixing Trichormus variabilis, for survival in nitrogen-deficient environments, to free-living growth in nitrate abundance. In nitrogen depletion, the cells are tethered to polysaccharide capsules of T. variabilis using nanotubular structures, presumably for nitrate acquisition. The composite culture failed to establish in industrial/domestic waste effluent. However, gradual exposure to increasing wastewater strength over time untethered Synechocystis cells and killed off T. variabilis. This switched the culture to a stress-acclimated monoculture of Synechocystis sp., which rapidly grew and flourished in wastewater, with ammonium and phosphate removal efficiencies of 99.4% and 97.5%, respectively. Therefore, this strain of Synechocystis sp. shows great promise for use in phycoremediation, with potential to rapidly generate biomass that can find use as a green feedstock for valuable bio-products in industrial applications.
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Anabaena variabilis/química , Biodegradación Ambiental , Synechocystis/química , Aguas Residuales/química , Anabaena variabilis/metabolismo , Biomasa , Conservación de los Recursos Naturales , Agua Dulce/química , Humanos , Residuos Industriales/análisis , Microalgas/química , Microalgas/metabolismo , Nitratos/química , Nitrógeno/metabolismo , Fosfatos/química , Synechocystis/metabolismo , Eliminación de Residuos Líquidos , Aguas Residuales/microbiología , Recursos HídricosRESUMEN
Plants respond rapidly to sudden environmental cues, often responding prior to changes in the hormone levels that coordinate these responses. How this is achieved is not fully understood. The integrative role of the phytohormone jasmonic acid (JA) relies upon the plant's ability to control the levels of JASMONATE ZIM (JAZ) domain-containing repressor proteins. Here, we demonstrate that regardless of intrinsic JA levels, Small Ubiquitin-like Modifier (SUMO)-conjugated JAZ proteins inhibit the JA receptor CORONATINE INSENSITIVE1 (COI1) from mediating non-SUMOylated JAZ degradation. The SUMO-deconjugating proteases OVERLY TOLERANT TO SALT1 (OTS1) and OTS2 regulate JAZ protein SUMOylation and stability. The ots1 ots2 double mutants accumulate SUMOylated and non-SUMOylated JAZ repressor proteins but show no change in endogenous JA levels compared with wild-type plants. SUMO1-conjugated JAZ proteins bind to COI1 independently of the JA mimic coronatine. SUMO inhibits JAZ binding to COI1. We identify the SUMO interacting motif in COI1 and demonstrate that this is vital to SUMO-dependent inhibition of COI1. Necrotroph infection of Arabidopsis thaliana promotes SUMO protease degradation, and this increases JAZ SUMOylation and abundance, which in turn inhibits JA signaling. This study reveals a mechanism for rapidly regulating JA responses, allowing plants to adapt to environmental changes.
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Proteínas de Arabidopsis/metabolismo , Ubiquitinas/metabolismo , Proteínas de Arabidopsis/genética , Ciclopentanos/metabolismo , Cisteína Endopeptidasas/genética , Cisteína Endopeptidasas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Oxilipinas/metabolismo , Transducción de Señal , Ubiquitinas/genéticaRESUMEN
BACKGROUND: To prevent folate deficiencies, many countries supplement various foodstuffs with folic acid. This compound is a synthetic oxidised folate that differs from naturally occurring reduced folates in its metabolism and uptake. Notably, safety reviews of folic acid supplementation have not considered interactions with gut bacteria. Here, we use the Caenorhabditis elegans - Escherichia coli animal- microbe model to examine a possible bacterial route for folic acid uptake. It has been assumed that supplements are taken up directly by the worm, especially because E. coli is unable to take up folates. However, E. coli, like many other bacteria, can transport the folate breakdown product, para-aminobenzoate-glutamate (PABA-glu), via AbgT and use it for bacterial folate synthesis. This pathway may impact host health because inhibition of bacterial folate synthesis increases C. elegans lifespan. RESULTS: Folic acid supplementation was found to rescue a C. elegans developmental folate-deficient mutant; however, a much higher concentration was required compared to folinic acid, a reduced folate. Unlike folinic acid, the effectiveness of folic acid supplementation was dependent on the E. coli gene, abgT, suggesting a bacterial route with PABA-glu uptake by E. coli as a first step. Surprisingly, we found up to 4% PABA-glu in folic acid preparations, including in a commercial supplement. Via breakdown to PABA-glu, folic acid increases E. coli folate synthesis. This pathway restores folate synthesis in a bacterial mutant defective in PABA synthesis, reversing the ability of this mutant to increase C. elegans lifespan. CONCLUSIONS: Folic acid supplementation in C. elegans occurs chiefly indirectly via bacterial uptake of breakdown products via E. coli AbgT, and can impact C. elegans development and longevity. Examining how folic acid supplementation affects bacterial folate synthesis in the human gut may help us to better understand the safety of folic acid supplementation.
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Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/microbiología , Suplementos Dietéticos , Escherichia coli/metabolismo , Ácido Fólico/metabolismo , Interacciones Microbiota-Huesped , Animales , Deficiencia de Ácido Fólico/prevención & control , Humanos , LongevidadRESUMEN
This is a discussion paper which examines the impact of austerity policies on the provision of mental health services in the United Kingdom. Austerity is a shorthand for a series of policies introduced by the Conservative and Liberal Democrat Coalition government in the UK from 2010 onwards. In response to the fiscal crisis following the bail out of the banks in 2008, it was argued that significant reductions in public spending were required. The background to these policies is examined before a consideration of their impact on mental health services. These policies had a disproportionate impact on people living in poverty. People with health problems including mental problems are overrepresented in this group. At the same time, welfare and community services are under increasing financial pressures having to respond to increased demand within a context of reduced budgets. There is increasing recognition of the role that social factors and adverse childhood experiences have in the development and trajectory of mental health problems. Mental health social workers, alongside other professionals, seek to explain mental distress by the use of some variant of a biopsychosocial model. The extent of mental health problems as a one of their measures of the impact of inequality. More unequal societies create greater levels of distress. There is a social gradient in the extent of mental health problems-the impact of severe mental illness means that many individuals are unable to work or, if they can return to work, they find it difficult to gain employment because of discrimination. The paper concludes that austerity and associated policies have combined to increase the overall burden of mental distress and marginalisation within the UK.
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Accesibilidad a los Servicios de Salud/economía , Servicios de Salud Mental/economía , Formulación de Políticas , Niño , Control de Costos , Humanos , Trastornos Mentales , Pobreza , Reino UnidoRESUMEN
Evidence is accumulating for molecular microcompartments formed when proteins interact in localized domains with the cytoskeleton, organelle surfaces, and intracellular membranes. To understand the potential functional significance of protein microcompartmentation in plants, we studied the interaction of the glycolytic enzyme fructose bisphosphate aldolase with actin in Arabidopsis thaliana. Homology modelling of a major cytosolic isozyme of aldolase, FBA8, suggested that the tetrameric holoenzyme has two actin binding sites and could therefore act as an actin-bundling protein, as was reported for animal aldolases. This was confirmed by in vitro measurements of an increase in viscosity of F-actin polymerized in the presence of recombinant FBA8. Simultaneously, interaction with F-actin caused non-competitive inhibition of aldolase activity. We did not detect co-localization of an FBA8-RFP fusion protein, expressed in an fba8-knockout background, with the actin cytoskeleton using confocal laser-scanning microscopy. However, we did find evidence for a low level of interaction using FRET-FLIM analysis of FBA8-RFP co-expressed with the actin-binding protein GFP-Lifeact. Furthermore, knockout of FBA8 caused minor alterations of guard cell actin cytoskeleton morphology and resulted in a reduced rate of stomatal closure in response to decreased humidity. We conclude that cytosolic aldolase can be microcompartmented in vivo by interaction with the actin cytoskeleton and may subtly modulate guard cell behaviour as a result.
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Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Arabidopsis/genética , Fructosa-Bifosfato Aldolasa/genética , Proteínas de Plantas/genética , Arabidopsis/enzimología , Arabidopsis/metabolismo , Citosol/metabolismo , Fructosa-Bifosfato Aldolasa/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Microscopía Confocal , Proteínas de Plantas/metabolismoRESUMEN
The metal affinities of metal-sensing transcriptional regulators co-vary with cellular metal concentrations over more than 12 orders of magnitude. To understand the cause of this relationship, we determined the structure of the Ni(II) sensor InrS and then created cyanobacteria (Synechocystis PCC 6803) in which transcription of genes encoding a Ni(II) exporter and a Ni(II) importer were controlled by InrS variants with weaker Ni(II) affinities. Variant strains were sensitive to elevated nickel and contained more nickel, but the increase was small compared with the change in Ni(II) affinity. All of the variant sensors retained the allosteric mechanism that inhibits DNA binding following metal binding, but a response to nickel in vivo was observed only when the sensitivity was set to respond in a relatively narrow (less than two orders of magnitude) range of nickel concentrations. Thus, the Ni(II) affinity of InrS is attuned to cellular metal concentrations rather than the converse.
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Níquel/análisis , Níquel/química , Proteínas Represoras/química , Tampones (Química) , Modelos Moleculares , Níquel/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Synechocystis/metabolismoRESUMEN
Notch has a well-defined role in controlling cell fate decisions in the embryo and the adult epidermis and immune systems, yet emerging evidence suggests Notch also directs non-cell-autonomous signalling in adult tissues. Here, we show that Notch1 works as a damage response signal. Epidermal Notch induces recruitment of immune cell subsets including RORγ(+) ILC3s into wounded dermis; RORγ(+) ILC3s are potent sources of IL17F in wounds and control immunological and epidermal cell responses. Mice deficient for RORγ(+) ILC3s heal wounds poorly resulting from delayed epidermal proliferation and macrophage recruitment in a CCL3-dependent process. Notch1 upregulates TNFα and the ILC3 recruitment chemokines CCL20 and CXCL13. TNFα, as a Notch1 effector, directs ILC3 localization and rates of wound healing. Altogether these findings suggest that Notch is a key stress/injury signal in skin epithelium driving innate immune cell recruitment and normal skin tissue repair.
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Epidermis/inmunología , Inmunidad Innata , Subgrupos Linfocitarios/metabolismo , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/inmunología , Receptor Notch1/inmunología , Heridas Penetrantes/inmunología , Animales , Movimiento Celular/inmunología , Quimiocina CCL20/genética , Quimiocina CCL20/inmunología , Quimiocina CXCL13/genética , Quimiocina CXCL13/inmunología , Epidermis/lesiones , Femenino , Regulación de la Expresión Génica , Interleucina-17/genética , Interleucina-17/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Ratones Noqueados , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/deficiencia , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Receptor Notch1/genética , Transducción de Señal/inmunología , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología , Cicatrización de Heridas/genética , Cicatrización de Heridas/inmunología , Heridas Penetrantes/genética , Heridas Penetrantes/patologíaRESUMEN
Sorghum bicolor is an important cereal crop grown on the arid and semi-arid regions of >98 different countries. These regions are such that this crop is often subjected to low water conditions, which can compromise yields. Stay-green sorghum plants are able to retain green leaf area for longer under drought conditions and as such have higher yields than their senescent counterparts. However, the molecular and physiological basis of this drought tolerance is yet to be fully understood. Here, a transcriptomic approach was used to compare gene expression between stay-green (B35) and senescent (R16) sorghum varieties. Ontological analysis of the differentially expressed transcripts identified an enrichment of genes involved with the 'response to osmotic stress' Gene Ontology (GO) category. In particular, delta1-pyrroline-5-carboxylate synthase 2 (P5CS2) was highly expressed in the stay-green line compared with the senescent line, and this high expression was correlated with higher proline levels. Comparisons of the differentially expressed genes with those that lie in known stay-green qualitative trait loci (QTLs) revealed that P5CS2 lies within the Stg1 QTL. Polymorphisms in known cis-elements were identified in the putative promoter region of P5CS2 and these could be responsible for the differences in the expression of this gene. This study provides greater insight into the stay-green trait in sorghum. This will be greatly beneficial not only to improve our understanding of drought tolerance mechanisms in sorghum, but also to facilitate the improvement of future sorghum cultivars by marker-assisted selection (MAS).
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Prolina/biosíntesis , Sorghum/genética , Envejecimiento/genética , Secuencia de Bases , ADN de Plantas , Sequías , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Análisis por Micromatrices , Datos de Secuencia Molecular , Fenotipo , Polimorfismo de Nucleótido Simple , Prolina/fisiología , Sorghum/fisiologíaRESUMEN
The cortical endoplasmic reticulum (ER) network in plants is a highly dynamic structure, and it contacts the plasma membrane (PM) at ER-PM anchor/contact sites. These sites are known to be essential for communication between the ER and PM for lipid transport, calcium influx, and ER morphology in mammalian and fungal cells. The nature of these contact sites is unknown in plants, and here, we have identified a complex that forms this bridge. This complex includes (1) NET3C, which belongs to a plant-specific superfamily (NET) of actin-binding proteins, (2) VAP27, a plant homolog of the yeast Scs2 ER-PM contact site protein, and (3) the actin and microtubule networks. We demonstrate that NET3C and VAP27 localize to puncta at the PM and that NET3C and VAP27 form homodimers/oligomers and together form complexes with actin and microtubules. We show that F-actin modulates the turnover of NET3C at these puncta and microtubules regulate the exchange of VAP27 at the same sites. Based on these data, we propose a model for the structure of the plant ER-PM contact sites.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Membrana Celular/metabolismo , Retículo Endoplásmico/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Microfilamentos/metabolismo , Nicotiana/metabolismo , Proteínas R-SNARE/metabolismo , Actinas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Citoesqueleto/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de la Membrana/genética , Proteínas de Microfilamentos/genética , Microtúbulos/metabolismo , Proteínas R-SNARE/genética , Nicotiana/genéticaRESUMEN
Safeners are agrochemicals which enhance tolerance to herbicides in cereals including wheat (Triticum aestivum L.) by elevating the expression of xenobiotic detoxifying enzymes, such as glutathione transferases (GSTs). When wheat plants were spray-treated with three safener chemistries, namely cloquintocet mexyl, mefenpyr diethyl and fenchlorazole ethyl, an apparently identical subset of GSTs derived from the tau, phi and lambda classes accumulated in the foliage. Treatment with the closely related mefenpyr diethyl and fenchlorazole ethyl enhanced seedling shoot growth, but this effect was not determined with the chemically unrelated cloquintocet mexyl. Focussing on cloquintocet mexyl, treatments were found to only give a transient induction of GSTs, with the period of elevation being dose dependent. Examining the role of safener metabolism in controlling these responses, it was determined that cloquintocet mexyl was rapidly hydrolysed to the respective carboxylic acid. Studies with cloquintocet showed that the acid was equally effective at inducing GSTs as the ester and appeared to be the active safener. Studies on the tissue induction of GSTs showed that whilst phi and tau class enzymes were induced in all tissues, the induction of the lambda enzymes was restricted to the meristems. To test the potential protective effects of cloquintocet mexyl in wheat on chemicals other than herbicides, seeds were pre-soaked in safeners prior to sowing on soil containing oil and a range of heavy metals. Whilst untreated seeds were unable to germinate on the contaminated soil, safener treatments resulted in seedlings briefly growing before succumbing to the pollutants. Our results show that safeners exert a range of protective and growth promoting activities in wheat that extend beyond enhancing tolerance to herbicides.
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Multiple-herbicide resistance (MHR) in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum) is a global problem leading to a loss of chemical weed control in cereal crops. Although poorly understood, in common with multiple-drug resistance (MDR) in tumors, MHR is associated with an enhanced ability to detoxify xenobiotics. In humans, MDR is linked to the overexpression of a pi class glutathione transferase (GSTP1), which has both detoxification and signaling functions in promoting drug resistance. In both annual rye-grass and black-grass, MHR was also associated with the increased expression of an evolutionarily distinct plant phi (F) GSTF1 that had a restricted ability to detoxify herbicides. When the black-grass A. myosuroides (Am) AmGSTF1 was expressed in Arabidopsis thaliana, the transgenic plants acquired resistance to multiple herbicides and showed similar changes in their secondary, xenobiotic, and antioxidant metabolism to those determined in MHR weeds. Transcriptome array experiments showed that these changes in biochemistry were not due to changes in gene expression. Rather, AmGSTF1 exerted a direct regulatory control on metabolism that led to an accumulation of protective flavonoids. Further evidence for a key role for this protein in MHR was obtained by showing that the GSTP1- and MDR-inhibiting pharmacophore 4-chloro-7-nitro-benzoxadiazole was also active toward AmGSTF1 and helped restore herbicide control in MHR black-grass. These studies demonstrate a central role for specific GSTFs in MHR in weeds that has parallels with similar roles for unrelated GSTs in MDR in humans and shows their potential as targets for chemical intervention in resistant weed management.