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1.
Physiol Plant ; 175(1): e13857, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36648218

RESUMO

The exchange of phosphorus (P) and carbon (C) between plants and arbuscular mycorrhizal fungi (AMF) is a major determinant of their mutualistic symbiosis. We explored the C dynamics in tomato (Solanum lycorpersicum) inoculated or not with Rhizophagus irregularis to study their growth response under different NaH2 PO4 concentrations (Null P, 0 mM; Low P, 0.065 mM; High P, 1.3 mM). The percentage of AMF colonization was similar in plants under Null and Low P, but severely reduced under High P. However, the AMF mass biomarker 16:1ω5 revealed higher fungal accumulation in inoculated roots under Low P, while more AMF spores were produced in the Null P. Under High P, AMF biomass and spores were strongly reduced. Plant growth response to mycorrhiza was negative under Null P, showing reduction in height, biovolume index, and source leaf (SL) area. Under Low P, inoculated plants showed a positive response (e.g., increased SL area), while inoculated plants under High P were similar to non-inoculated plants. AMF promoted the accumulation of soluble sugars in the SL under all fertilization levels, whereas the soluble sugar level decreased in roots under Low P in inoculated plants. Transcriptional upregulation of SlLIN6 and SlSUS1, genes related to carbohydrate metabolism, was observed in inoculated roots under Null P and Low P, respectively. We conclude that P-limiting conditions that increase AMF colonization stimulate plant growth due to an increase in the source and sink strength. Our results suggest that C partitioning and allocation to different catabolic pathways in the host are influenced by AMF performance.


Assuntos
Micorrizas , Micorrizas/fisiologia , Raízes de Plantas/metabolismo , Simbiose , Plantas , Carboidratos , Lipídeos
2.
Health Promot Pract ; 24(6): 1151-1162, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-36050932

RESUMO

Movements designed to engage youth in tobacco control have been an important part of tobacco prevention for decades. Today, young people are increasingly diverse, and their primary issues of concern are gun control, racism, mental health, and climate change. To engage today's young people, tobacco control programs need to draw connections between youth's identities, top issues, and tobacco. UpRISE is a social justice youth tobacco control movement that engages diverse youth in identifying the root causes of youth nicotine use. In 2018-2019, 21 youth-serving organizations and schools hosted youth coalitions. Coalitions engaged in a six-session workbook called "Getting to the root cause," and adults were provided training and reflective supervision. Pre/post surveys with youth participants (n = 180) and end-of-year interviews with adult facilitators (n = 22) were used to assess outcomes. The primary outcomes were supportive adult relationships, youth voice in decision-making, anti-tobacco industry attitudes and beliefs, psychological empowerment, critical consciousness, and global belief in a just world. Quantitative measures of supportive adult relationships, youth voice in decision-making, psychological empowerment, and anti-tobacco industry attitudes and beliefs all increased significantly over time (p < .0001, p < .0001, p < .0001, p = .0034, respectively). Critical consciousness and global belief in a just world did not change significantly. During interviews, adults reported learning how: to engage in youth-adult partnerships, the tobacco industry abused its power, to engage in critical reflection about power. Adults also felt empowered. UpRISE may be a promising approach to increase racially diverse youth's engagement in social justice-oriented tobacco control efforts that advance equity.


Assuntos
Empoderamento , Controle do Tabagismo , Adulto , Humanos , Adolescente , Nicotiana , Instituições Acadêmicas , Justiça Social
3.
Plant Cell Environ ; 44(6): 1961-1976, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33529396

RESUMO

Plants host a diverse microbiome and differentially react to the fungal species living as endophytes or around their roots through emission of volatiles. Here, using divided Petri plates for Arabidopsis-T. atroviride co-cultivation, we show that fungal volatiles increase endogenous sugar levels in shoots, roots and root exudates, which improve Arabidopsis root growth and branching and strengthen the symbiosis. Tissue-specific expression of three sucrose phosphate synthase-encoding genes (AtSPS1F, AtSPS2F and AtSPS3F), and AtSUC2 and SWEET transporters revealed that the gene expression signatures differ from those of the fungal pathogens Fusarium oxysporum and Alternaria alternata and that AtSUC2 is largely repressed either by increasing carbon availability or by perception of the fungal volatile 6-pentyl-2H-pyran-2-one. Our data point to Trichoderma volatiles as chemical signatures for sugar biosynthesis and exudation and unveil specific modulation of a critical, long-distance sucrose transporter in the plant.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Hypocreales/química , Sacarose/metabolismo , Compostos Orgânicos Voláteis/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Transporte Biológico , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucose/metabolismo , Glucosiltransferases/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Exsudatos de Plantas/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Pironas/farmacologia , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Sacarose/farmacologia
4.
Biometals ; 34(3): 603-620, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33772672

RESUMO

As sessile organisms, plants respond to changing environments modulating their genetic expression, metabolism and postembryonic developmental program (PDP) to adapt. Among environmental stressor, lead (Pb) is one of the most hazardous pollutants which limits crop productivity. Here, we describe in detail the effects of a wide range of concentrations of Pb on growth and development and a possible convergence with phosphate (Pi) starvation response. We found that the response to Pb presents a biphasic curve dose response in biomass accumulation: below 400 µM show a stimulatory effect meanwhile at Pb doses up to 600 µM effects are inhibitory. We found that +Pb (800 µM) modifies root system architecture (RSA) and induces acidification media, according to in silico ion interaction, in the growing medium Pb and Pi coprecipitate and plants grow in both Pi deficiency and Pb stress at the same time, however in spite of seedlings are under Pi starvation AtPT2 expression are Pb downregulated indicating that in addition to Pi starvation stress, Pb regulates physiological responses in root system. Using the mutants stop1, lpr1/2 and lpi3, which are affected in Pi starvation response, we found that changes in RSA by +Pb is genetically regulated and there are shared pathways with Pi starvation response mediated by PDR2-LPR1/2 and LPI3 pathways since lpr1/2 and lpi3 mutants are insensitive to +Pb and Pi starvation. Taking together, these results indicate that similar changes in RSA induced by independent environmental stimuli +Pb and Pi starvation are due to similar mediated response by PDR2-LPR1/2 pathway.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Chumbo/farmacologia , Oxirredutases/metabolismo , Fosfatos/metabolismo , Raízes de Plantas/efeitos dos fármacos , Plântula/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Relação Dose-Resposta a Droga , Chumbo/química , Chumbo/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
5.
Biometals ; 34(6): 1247-1261, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34417897

RESUMO

Chromium (Cr) is a nonessential element for plants that is extremely toxic at high concentrations. Zea mays L. is a species of plant that has developed adaptive mechanisms to increase its tolerance and absorption capacity for this metal. One effective mechanism is to form associations with arbuscular mycorrhizal fungi (AMF), which help the plant cope with stress from heavy metals such as Cr. However, it is still not clear which species of AMF are more efficient as bioremediating agents for plants of agricultural importance. Here, we evaluated the effect of Gigaspora gigantea and Rhizophagus irregularis as protective agents of maize plants in soils contaminated with Cr at concentrations of 0, 48.5, 97 and 194 mg kg-1 under greenhouse conditions. Maize tolerance to Cr was corroborated, as well as increased absorption of this element by plants associated with both species of AMF. G. gigantea caused an increase in nitrogen content and greater translocation of Cr to the aerial part of the plant; R. irregularis registered an increase in the formation of arbuscules and vesicles with increasing metal concentration and greater retention of Cr in the roots of the plants. Based on these results, we can conclude that the analyzed species of fungi use different strategies, with similar effectiveness, to enhance the absorption capacity of Cr by the plant and influence the differential deposition of this metal in various parts of the plant.


Assuntos
Metais Pesados , Micorrizas , Poluentes do Solo , Cromo/farmacologia , Metais Pesados/farmacologia , Micorrizas/química , Raízes de Plantas , Solo/química , Zea mays
6.
Plant Cell Environ ; 43(8): 1989-1999, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32400913

RESUMO

Plants adapt to soil injury and biotic stress via cell regeneration. In Arabidopsis, root tip damage by genotoxic agents, antibiotics, UV light and cutting induces a program that recovers the missing tissues through activation of stem cells and involves ethylene response factor 115 (ERF115), which triggers cell replenishment. Here, we show that mutation of the gene encoding an MED18 subunit of the transcriptional MEDIATOR complex and chromate [Cr(VI)], an environmental pollutant, synergistically trigger a developmental program that enables the splitting of the meristem in vivo to produce twin roots. Expression of the quiescent centre gene marker WOX5, auxin-inducible DR5:GFP reporter and the ERF115 factor traced the changes in cell identity during the conversion of single primary root meristems into twin roots and were induced in an MED18 and chromate-dependent manner during the root twinning events, which also required auxin redistribution and signalling mediated by IAA14/SOLITARY ROOT (SLR1). Splitting of the root meristem allowed dichotomous root branching in Arabidopsis, a poorly understood process in which stem cells may act to enable whole organ regeneration.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Complexo Mediador/genética , Meristema/genética , Raízes de Plantas/genética , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/metabolismo , Cromo/farmacologia , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/genética , Ácidos Indolacéticos/metabolismo , Complexo Mediador/metabolismo , Meristema/efeitos dos fármacos , Mutação , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Fatores de Transcrição/genética
7.
Genet Mol Biol ; 43(1): e20190221, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32105289

RESUMO

Auxin regulates a plethora of events during plant growth and development, acting in concert with other phytohormones. YUCCA genes encode flavin monooxygenases that function in tryptophan-dependent auxin biosynthesis. To understand the contribution of the YUCCA4 (YUC4) gene on auxin homeostasis, plant growth and interaction with abscisic acid (ABA) signaling, 35S::YUC4 seedlings were generated, which showed elongated hypocotyls with hyponastic leaves and changes in root system architecture that correlate with enhanced auxin responsive gene expression. Differential expression of PIN1, 2, 3 and 7 auxin transporters was detected in roots of YUC4 overexpressing seedlings compared to the wild-type: PIN1 was down-regulated whereas PIN2, PIN3 and PIN7 were up-regulated. Noteworthy, 35S::YUC4 lines showed enhanced sensitivity to ABA on seed germination and post-embryonic root growth, involving ABI4 transcription factor. The auxin reporter genes DR5::GUS, DR5::GFP and BA3::GUS further revealed that abscisic acid impairs auxin responses in 35S::YUC4 seedlings. Our results indicate that YUC4 overexpression influences several aspects of auxin homeostasis and reveal the critical roles of ABI4 during auxin-ABA interaction in germination and primary root growth.

8.
Rev Invest Clin ; 72(3): 159-164, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584322

RESUMO

BACKGROUND: The ideal treatment of coronavirus disease (COVID)-19 has yet to be defined, but convalescent plasma (CoPla) has been successfully employed. OBJECTIVE: The objective of the study was to study the safety and outcomes of the administration of CoPla to individuals with severe COVID-19 in an academic medical center. METHODS: Ten patients were prospectively treated with plasma from COVID-19 convalescent donors. RESULTS: Over 8 days, the sequential organ failure assessment score dropped significantly in all patients, from 3 to 1.5 (p = 0.014); the Kirby index (PaO2/FiO2) score increased from 124 to 255, (p < 0.0001), body temperature decreased significantly from 38.1 to 36.9°C (p = 0.0058), and ferritin levels also dropped significantly from 1736.6 to 1061.8 ng/ml (p = 0.0001). Chest X-rays improved in 7/10 cases and in 6/10, computerized tomography scans also revealed improvement of the lung injury. Decreases in C-reactive protein and D-dimer levels were also observed. Three of five patients on mechanical ventilation support could be extubated, nine were transferred to conventional hospital floors, and six were sent home; two patients died. The administration of CoPla had no side effects and the 24-day overall survival was 77%. CONCLUSIONS: Although other treatments were also administered to the patients and as a result data are difficult to interpret, it seems that the addition of CoPla improved pulmonary function.


Assuntos
Betacoronavirus , Infecções por Coronavirus/terapia , Pneumonia Viral/terapia , Adulto , Idoso , Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , Biomarcadores , Temperatura Corporal , Proteína C-Reativa/análise , COVID-19 , Terapia Combinada , Convalescença , Infecções por Coronavirus/sangue , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/tratamento farmacológico , Feminino , Ferritinas/sangue , Humanos , Imunização Passiva , Estimativa de Kaplan-Meier , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pandemias , Projetos Piloto , Plasma , Pneumonia Viral/sangue , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/tratamento farmacológico , Estudos Prospectivos , Respiração Artificial , SARS-CoV-2 , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem , Tratamento Farmacológico da COVID-19 , Soroterapia para COVID-19
9.
Mol Ther ; 26(1): 208-218, 2018 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-29107477

RESUMO

Because muscle contains osteoprogenitor cells and has a propensity to form bone, we have explored its utility in healing large osseous defects. Healing is achieved by the insertion of muscle fragments transduced with adenovirus encoding BMP-2 (Ad.BMP-2). However, it is not known whether the genetically modified muscle contributes osteoprogenitor cells to healing defects or merely serves as a local source of BMP-2. This question is part of the larger debate on the fate of progenitor cells introduced into sites of tissue damage to promote regeneration. To address this issue, we harvested fragments of muscle from rats constitutively expressing GFP, transduced them with Ad.BMP-2, and implanted them into femoral defects in wild-type rats under various conditions. GFP+ cells persisted within defects for the entire 8 weeks of the experiments. In the absence of bone formation, these cells presented as fibroblasts. When bone was formed, GFP+ cells were present as osteoblasts and osteocytes and also among the lining cells of new blood vessels. The genetically modified muscle thus contributed progenitor cells as well as BMP-2 to the healing defect, a property of great significance in light of the extensive damage to soft tissue and consequent loss of endogenous progenitors in problematic fractures.


Assuntos
Proteína Morfogenética Óssea 2/metabolismo , Osteoblastos/metabolismo , Osteogênese , Absorciometria de Fóton , Animais , Biópsia , Regeneração Óssea , Expressão Gênica , Genes Reporter , Imuno-Histoquímica , Masculino , Músculo Esquelético/metabolismo , RNA Mensageiro/genética , Ratos , Cicatrização , Microtomografia por Raio-X
10.
An Acad Bras Cienc ; 91(2): e20180468, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31241699

RESUMO

This study evaluates the antibacterial, cytotoxic activities, and phytochemical composition, of Callistemon citrinus, Hibiscus rosa-sinensis and Plumbago auriculata leaves and flowers, three ornamental plants in Mexico. However, in other countries offers a range of other uses. Ethanol extracts of C. citrinus leaf and flower presented stronger antibacterial activity than the extracts obtained from the other two plants. C. citrinus leaf showed low cytotoxicity (LC50 <600 µg/mL) on the brine shrimp test, whereas the ethanol extracts of H. rosa-sinensis and P. auriculata leaves showed no cytotoxic activity. Flower extracts obtained from the three plants did no exhibit cytotoxicity. GC-MS analysis revealed that the ethanol extract of P. auriculata leaf contained lupeol triterpene and lupeol acetate, neither of them have been previously reported in this genus. Gamma sitosterol was present in the leaf and flower extracts of P. auriculata. Higher contents of linoleic and linolenic acids were found in extracts of H. rosa-sinensis leaves and flowers. The ability of the ethanol extracts of C. citrinus leaves and flowers to inhibit the growth of Gram-positive and Gram-negative bacteria indicates a potentially broad antimicrobial spectrum. Moreover, the absence of cytotoxicity suggests the potential use of this plant to treat microbial infections.


Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Hibiscus/química , Myrtaceae/química , Extratos Vegetais/farmacologia , Plumbaginaceae/química , Animais , Antibacterianos/toxicidade , Artemia/efeitos dos fármacos , México , Testes de Sensibilidade Microbiana , Extratos Vegetais/toxicidade , Testes de Toxicidade
11.
Sensors (Basel) ; 19(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875905

RESUMO

There is a strong demand in the oil and gas industry to develop alternatives to manual inspection. This paper presents AeroX, a novel aerial robotic manipulator that provides physical contact inspection with unprecedented capabilities. AeroX has a semi-autonomous operation, which provides interesting advantages in contact inspection. In the free-flight mode, the pilot guides the robot until performing contact with its end-effector on the surface to be inspected. During contact, AeroX is in its fully-autonomous global navigation satellite system (GNSS)-free contact⁻flight mode, in which the robot keeps its relative position w.r.t. the surface contact point using only its internal sensors. During autonomous flight, the inspector can move-with uninterrupted contact-the end-effector on the surface for accurately selecting the points where to perform A-scan measurements or continuous B-scan or C-scan inspections. AeroX adopts an eight-tilted rotor configuration and a simple and efficient design, which provides high stability, maneuverability, and robustness to rotor failure. It can perform contact inspection on surfaces at any orientation, including vertical, inclined, horizontal-top or horizontal-bottom, and its operation can be easily integrated into current maintenance operations in many industries. It has been extensively validated in outdoor experiments including a refinery and has been awarded the EU Innovation Radar Prize 2017.

12.
Molecules ; 24(1)2018 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-30583465

RESUMO

Capsaicin is an agonist of the transient receptor potential vanilloid type 1 (TRPV1) channel, which has been related to the pathophysiology of kidney disease secondary to diabetes. This study aimed to evaluate the chronic effect of capsaicin administration on biomarkers of kidney injury in an experimental rat model of diabetes. Male Wistar rats were assigned to four groups: (1) healthy controls without diabetes (CON), (2) healthy controls plus capsaicin at 1 mg/kg/day (CON + CAPS), (3) experimental diabetes without capsaicin (DM), and (4) experimental diabetes plus capsaicin at 1 mg/kg/day (DM + CAPS). For each group, 24-h urine samples were collected to determine diuresis, albumin, cystatin C, ß2 microglobulin, epidermal growth factor (EGF), alpha (1)-acid glycoprotein, and neutrophil gelatinase-associated lipocalin (NAG-L). Blood samples were drawn to measure fasting glucose. After 8 weeks, the CON + CAPS and DM + CAPS groups showed increased diuresis compared to the CON and DM groups, but the difference was significant only in the DM + CAPS group. The two-way ANOVA only showed a statistically significant effect of CAPS on the urinary EGF levels, as well as a tendency to have a significant effect in the urinary NAG-L levels. The EGF levels decreased in both CAPS-treated groups, but the change was only significant in the CON + CAPS group vs. CON group; and the NAG-L levels were lower in both CAPS-treated groups. These results show that capsaicin had a diuretic effect in healthy and diabetic rats; additionally, it increased the urinary EGF levels and tended to decrease the urinary NAG-L levels.


Assuntos
Capsaicina/farmacologia , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/metabolismo , Análise de Variância , Animais , Biomarcadores , Glicemia , Peso Corporal , Diabetes Mellitus Experimental , Nefropatias Diabéticas/patologia , Diuréticos/farmacologia , Masculino , Ratos , Ratos Wistar , Canais de Cátion TRPV/metabolismo
13.
Genet Mol Biol ; 40(3): 643-655, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28850635

RESUMO

Proteins of the Split ends (Spen) family are characterized by an N-terminal domain, with one or more RNA recognition motifs and a SPOC domain. In Arabidopsis thaliana, the Spen protein FPA is involved in the control of flowering time as a component of an autonomous pathway independent of photoperiod. The A. thaliana genome encodes another gene for a putative Spen protein at the locus At4g12640, herein named AtSpen2. Bioinformatics analysis of the AtSPEN2 SPOC domain revealed low sequence similarity with the FPA SPOC domain, which was markedly lower than that found in other Spen proteins from unrelated plant species. To provide experimental information about the function of AtSpen2, A. thaliana plants were transformed with gene constructs of its promoter region with uidA::gfp reporter genes; the expression was observed in vascular tissues of leaves and roots, as well as in ovules and developing embryos. There was absence of a notable phenotype in knockout and overexpressing lines, suggesting that its function in plants might be specific to certain endogenous or environmental conditions. Our results suggest that the function of Atspen2 diverged from that of fpa due in part to their different transcription expression pattern and divergence of the regulatory SPOC domain.

14.
Biometals ; 28(2): 353-65, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25702099

RESUMO

Morphological root plasticity optimizes nutrient and water uptake by plants and is a promising target to improve tolerance to metal toxicity. Exposure to sublethal chromate [Cr(VI)] concentrations inhibits root growth, decreases photosynthesis and compromises plant development and productivity. Despite the increasing environmental problem that Cr(VI) represents, to date, the Cr tolerance mechanisms of plants are not well understood, and it remains to be investigated whether root architecture remodelling is important for plant adaptation to Cr(VI) stress. In this report, we analysed the growth response of Arabidopsis thaliana seedlings to concentrations of Cr(VI) that strongly repress primary and lateral root growth. Interestingly, adventitious roots started developing, branched and allowed seedlings to grow under highly growth-repressing Cr(VI) concentrations. Cr(VI) negatively regulates auxin transport and response gene expression in the primary root tip, as evidenced by decreased expression of auxin-related reporters DR5::GFP, DR5::uidA and PIN1::PIN1::GFP, and then, another auxin maximum is established at the site of adventitious root initiation that drives adventitious root organogenesis. Both primary root growth inhibition and adventitious root formation induced by high Cr(VI) levels are blocked by a gain-of-function mutation in the SOLITARY-ROOT/IAA14 gene of Arabidopsis. These data provide evidence that suggests a critical role for auxin transport and signalling via IAA14/SLR1 in the developmental program linking Cr(VI) to root architecture remodelling.


Assuntos
Arabidopsis/fisiologia , Cromatos/toxicidade , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas/fisiologia , Compostos de Potássio/toxicidade , Adaptação Fisiológica , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Raízes de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos
15.
Plant Mol Biol ; 86(1-2): 35-50, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24928490

RESUMO

Soil contamination by hexavalent chromium [Cr(VI) or chromate] due to anthropogenic activities has become an increasingly important environmental problem. To date few studies have been performed to elucidate the signaling networks involved on adaptive responses to (CrVI) toxicity in plants. In this work, we report that depending upon its concentration, Cr(VI) alters in different ways the architecture of the root system in Arabidopsis thaliana seedlings. Low concentrations of Cr (20-40 µM) promoted primary root growth, while concentrations higher than 60 µM Cr repressed growth and increased formation of root hairs, lateral root primordia and adventitious roots. We analyzed global gene expression changes in seedlings grown in media supplied with 20 or 140 µM Cr. The level of 731 transcripts was significantly modified in response to Cr treatment with only five genes common to both Cr concentrations. Interestingly, 23 genes related to iron (Fe) acquisition were up-regulated including IRT1, YSL2, FRO5, BHLH100, BHLH101 and BHLH039 and the master controllers of Fe deficiency responses PYE and BTS were specifically activated in pericycle cells. It was also found that increasing concentration of Cr in the plant correlated with a decrease in Fe content, but increased both acidification of the rhizosphere and activity of the ferric chelate reductase. Supply of Fe to Cr-treated Arabidopsis allowed primary root to resume growth and alleviated toxicity symptoms, indicating that Fe nutrition is a major target of Cr stress in plants. Our results show that low Cr levels are beneficial to plants and that toxic Cr concentrations activate a low-Fe rescue system.


Assuntos
Arabidopsis/efeitos dos fármacos , Cromatos/toxicidade , Poluentes do Solo/toxicidade , Arabidopsis/genética , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Ferro/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/fisiologia , Transdução de Sinais/efeitos dos fármacos
16.
Biometals ; 27(2): 363-70, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24549595

RESUMO

Soil contamination by hexavalent chromium [Cr(VI) or chromate] due to anthropogenic activities has become an increasingly important environmental problem. Mineral nutrients such as phosphate (Pi), sulfate and nitrate have been reported to attenuate Cr(VI) toxicity, but the underlying mechanisms remain to be clarified. Here, we show that chromate activates the expression of low-Pi inducible reporter genes AtPT1 and AtPT2 in Arabidopsis thaliana transgenic seedlings. Primary-root growth was inhibited by 60 % in AtPT2::uidA-expressing seedlings upon exposure to 140-µM Cr(VI). However, increasing the Pi and sulfate supply to the seedlings that were experiencing Cr(VI) toxicity completely and partially restored the root growth, respectively. This effect correlated with the Cr(VI)-induced AtPT2::uidA expression being completely reversed by addition of Pi. To evaluate whether the nutrient supply may affect the endogenous level of Cr in plants grown under toxic Cr(VI) levels, the contents of Cr were measured (by ICP-MS analyses) in seedlings treated with Cr and with or without Pi, sulfate or nitrate. It was found that Cr accumulation increases tenfold in plants treated with 140-µM Cr(VI) without modifying the phosphorus concentration in the plant. In contrast, the supply of Pi specifically decreased the Cr content to levels similar to those found in seedlings grown in medium without chromate. Taken together, these results show that in A. thaliana seedlings the uptake of Cr(VI) is reduced by Pi. Moreover, our data indicate that Pi and sulfate supplements may be useful in strategies for handling Cr-contaminated soils.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Cromatos/metabolismo , Cromo/farmacocinética , Cromo/toxicidade , Fosfatos/farmacologia , Arabidopsis/genética , Proteínas de Arabidopsis/antagonistas & inibidores , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Relação Dose-Resposta a Droga , Proteínas de Transporte de Fosfato/antagonistas & inibidores , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Plântula/efeitos dos fármacos , Relação Estrutura-Atividade
17.
Proc Natl Acad Sci U S A ; 108(17): 7253-8, 2011 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-21482761

RESUMO

Microorganisms and their hosts communicate with each other through an array of signals. The plant hormone auxin (indole-3-acetic acid; IAA) is central in many aspects of plant development. Cyclodipeptides and their derivative diketopiperazines (DKPs) constitute a large class of small molecules synthesized by microorganisms with diverse and noteworthy activities. Here, we present genetic, chemical, and plant-growth data showing that in Pseudomonas aeruginosa, the LasI quorum-sensing (QS) system controls the production of three DKPs--namely, cyclo(L-Pro-L-Val), cyclo(L-Pro-L-Phe), and cyclo(L-Pro-L-Tyr)--that are involved in plant growth promotion by this bacterium. Analysis of all three bacterial DKPs in Arabidopsis thaliana seedlings provided detailed information indicative of an auxin-like activity, based on their efficacy at modulating root architecture, activation of auxin-regulated gene expression, and response of auxin-signaling mutants tir1, tir1 afb2 afb3, arf7, arf19, and arf7arf19. The observation that QS-regulated bacterial production of DKPs modulates auxin signaling and plant growth promotion establishes an important function for DKPs mediating prokaryote/eukaryote transkingdom signaling.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Proteínas de Bactérias , Ácidos Indolacéticos/metabolismo , Peptídeos Cíclicos , Pseudomonas aeruginosa/química , Plântula/crescimento & desenvolvimento , Transdução de Sinais/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/farmacologia , Mutação , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Plântula/genética
18.
J Prev (2022) ; 45(2): 303-321, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38353805

RESUMO

Prevention Science seeks to advance the prevention research and to translate scientific advances into the promotion of healthy development for all youth. Despite tremendous progress creating a robust evidence-base and set of translational tools, elaborations and expansions for equity are required. Our collective errors of omission as prevention researchers have left prevention practitioners and policy-makers without sufficient information to identify strategies that have been demonstrated to prevent behavioral health problems in young people who identify as Black, Indigenous, or other People of Color (BIPOC). We first describe the current shortcomings of available evidence, and then we call for individual and collective action to conceptualize equity-enhancing prevention, sample more inclusively, and improve analytic approaches such that we can truly promote the healthy development of all youth.


Assuntos
Pesquisa sobre Serviços de Saúde , Nível de Saúde , Humanos , Adolescente , Estados Unidos , Grupos Raciais
19.
J Aging Stud ; 67: 101186, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38012946

RESUMO

The aim of this qualitative, phenomenological study was to understand how older adults cope with experiences of ageism and racism through an intersectional lens. Twenty adults 60+ residing in the U.S. Mountain West who identified as Black, Hispanic/Latino(a), Asian-American/Pacific Islander, Indigenous, or White participated individually in a one-hour, semi-structured interview. A team of five coders engaged in an inductive coding process through independent coding followed by critical discussion. Peer debriefing enhanced credibility. Nine themes were organized by three umbrella categories: Coping with ageism: 1) distancing via self-determination/defying stereotypes, 2) distancing by helping others; Coping with racism: 3) resistance, 4) exhaustion; Coping with both ageism and racism: 5) increased awareness through aging, 6) healthy lifestyle, 7) education, 8) acceptance/ 'let it go', and 9) avoidance. Novel findings include how older adults may cope with ageism and racism via increased awareness through aging and with ageism specifically by helping peer older adults, although instances of internalized ageism were noted and discussed. The themes exemplify problem-focused (e.g., helping others) and emotion-focused (acceptance), as well as individual (e.g., self-determination) and collective (e.g., resistance) coping strategies. This study can serve as a resource for practitioners in applying a more nuanced understanding of the ways older adults cope with ageism and racism in later life.


Assuntos
Etarismo , Racismo , Humanos , Idoso , Envelhecimento , Adaptação Psicológica , Pesquisa Qualitativa
20.
J Gerontol B Psychol Sci Soc Sci ; 78(5): 880-890, 2023 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-36809313

RESUMO

OBJECTIVES: Ageism is a prevalent, insidious social justice issue that has harmful effects on the health of older adults. Preliminary literature explores the intersectionality of ageism with sexism, ableism, and ageism experienced among LGBTQ+ older adults. Yet, the intersectionality of ageism with racism remains largely absent from the literature. Therefore, this study explores the lived experience of the intersectionality of ageism and racism among older adults. METHODS: This qualitative study applied a phenomenological approach. Twenty participants 60+ years of age (M = 69, standard deviation = 8.84) in the U.S. Mountain West identifying as Black, Latino(a), Asian-American/Pacific Islander, Indigenous, or White engaged in a 1-hr interview between February and July 2021. A 3-cycle coding process applied constant comparison methods. Five coders independently coded interviews, engaging in critical discussion to resolve disagreements. An audit trail, member checking, and peer debriefing enhanced credibility. RESULTS: This study focuses on individual-level experiences exemplified by 3 umbrella themes and 7 subthemes. The subthemes are (a) compounding oppression, (b) intersection of disparities, (c) White privilege, (d) racism and ageism: being tokenized or ignored, (e) ageism and racism: unspoken bias, (f) racism versus ageism: overt or covert? and (g) racism versus ageism: differentiated or ubiquitous? DISCUSSION: The findings indicate how ageism may be racialized through stereotypes related to mental (in)capability. Practitioners can apply the findings to enhance support for older adults by designing interventions aimed at reducing racialized ageist stereotypes and increasing collaboration through education across anti-ageism/anti-racism initiatives. Future research should focus on the impacts of the intersectionality of ageism and racism on specific health outcomes in addition to structural-level interventions.


Assuntos
Etarismo , Racismo , Humanos , Idoso , Discriminação Social
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