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1.
Autism Res ; 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31961493

RESUMO

Angelman syndrome (AS) is a rare genetic disorder characterized by severe intellectual disability, seizures, lack of speech, and ataxia. The gene responsible for AS was identified as Ube3a and it encodes for E6AP, an E3 ubiquitin ligase. Currently, there is very little known about E6AP's mechanism of action in vivo or how the lack of this protein in neurons may contribute to the AS phenotype. Elucidating the mechanistic action of E6AP would enhance our understanding of AS and drive current research into new avenues that could lead to novel therapeutic approaches that target E6AP's various functions. To facilitate the study of AS, we have generated a novel rat model in which we deleted the rat Ube3a gene using CRISPR. The AS rat phenotypically mirrors human AS with loss of Ube3a expression in the brain and deficits in motor coordination as well as learning and memory. This model offers a new avenue for the study of AS. Autism Res 2019, 00: 1-12. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Angelman syndrome (AS) is a rare genetic disorder characterized by severe intellectual disability, seizures, difficulty speaking, and ataxia. The gene responsible for AS was identified as UBE3A, yet very little is known about its function in vivo or how the lack of this protein in neurons may contribute to the AS phenotype. To facilitate the study of AS, we have generated a novel rat model in which we deleted the rat Ube3a gene using CRISPR. The AS rat mirrors human AS with loss of Ube3a expression in the brain and deficits in motor coordination as well as learning and memory. This model offers a new avenue for the study of AS.

2.
Seizure ; 70: 90-96, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31323566

RESUMO

PURPOSE: To evaluate whether the onset of pediatric refractory status epilepticus (rSE) is related to time of day. METHOD: We analyzed the time of day for the onset of rSE in this prospective observational study performed from June 2011 to May 2019 in pediatric patients (1 month to 21 years of age). We evaluated the temporal distribution of pediatric rSE utilizing a cosinor analysis. We calculated the midline estimating statistic of rhythm (MESOR) and amplitude. MESOR is the estimated mean number of rSE episodes per hour if they were evenly distributed. Amplitude is the difference between MESOR and maximum rSE episodes/hour, or between MESOR and minimum rSE episodes/hour. We also evaluated the temporal distribution of time to treatment. RESULTS: We analyzed 368 patients (58% males) with a median (p25 - p75) age of 4.2 (1.3-9.7) years. The MESOR was 15.3 (95% CI: 13.9-16.8) and the amplitude was 3.2 (95% CI: 1.1-5.3), p = 0.0024, demonstrating that the distribution is not uniform, but better described as varying throughout the day with a peak in the morning (11am-12 pm) and trough at night (11 pm-12 am). The duration from rSE onset to application of the first non-benzodiazepine antiseizure medication peaked during the early morning (2am-3 am) with a minimum during the afternoon (2 pm-3 pm) (p = 0.0179). CONCLUSIONS: The distribution of rSE onset is not uniform during the day. rSE onset shows a 24-h distribution with a peak in the mid-morning (11am-12 pm) and a trough at night (11 pm-12am).

3.
J Clin Neurophysiol ; 36(5): 365-370, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31166226

RESUMO

PURPOSE: We aimed to determine whether clinical EEG reports obtained from children in the intensive care unit with refractory status epilepticus could provide data for comparative effectiveness research studies. METHODS: We conducted a retrospective descriptive study to assess the documentation of key variables within clinical continuous EEG monitoring reports based on the American Clinical Neurophysiology Society's standardized EEG terminology for children with refractory status epilepticus from 10 academic centers. Two pediatric electroencephalographers reviewed the EEG reports. We compared reports generated using free text or templates. RESULTS: We reviewed 191 EEG reports. Agreement between the electroencephalographers regarding whether a variable was described in the report ranged from fair to very good. The presence of electrographic seizures (ES) was documented in 46% (87/191) of reports, and these reports documented the time of first ES in 64% (56/87), ES duration in 72% (63/85), and ES frequency in 68% (59/87). Reactivity was documented in 16% (31/191) of reports, and it was more often documented in template than in free-text reports (40% vs. 14%, P = 0.006). Other variables were not differentially reported in template versus free-text reports. CONCLUSIONS: Many key EEG features are not documented consistently in clinical continuous EEG monitoring reports, including ES characteristics and reactivity assessment. Standardization may be needed for clinical EEG reports to provide informative data for large multicenter observational studies.


Assuntos
Epilepsia Resistente a Medicamentos/diagnóstico , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletroencefalografia/métodos , Hospitais Pediátricos , Estado Epiléptico/diagnóstico , Estado Epiléptico/fisiopatologia , Adolescente , Criança , Pré-Escolar , Eletroencefalografia/tendências , Feminino , Hospitais Pediátricos/tendências , Humanos , Lactente , Unidades de Terapia Intensiva/tendências , Masculino , Monitorização Fisiológica/métodos , Monitorização Fisiológica/tendências , Estudos Retrospectivos , Convulsões/diagnóstico , Convulsões/fisiopatologia , Adulto Jovem
4.
Can J Microbiol ; 65(3): 185-190, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30398901

RESUMO

A biocontrol bacterium, Pseudomonas chlororaphis O6 promotes plant health through multifaceted mechanisms. In this study, we used P. chlororaphis O6 mutants to examine metabolites with aphicidal activity. Direct application of intact P. chlororaphis cells to the surface of second-instar nymphs of the green peach aphid resulted in no mortality. However, nymphs died when exposed only to the volatiles produced by the P. chlororaphis O6 wild-type strain grown on rich media. Mutants lacking the production of two antibiotics, phenazine and pyrrolnitrin, or the insect toxin FitD retained the aphicidal potential of the wild-type strain. However, the volatiles produced by mutants deficient in the production of hydrogen cyanide (HCN) or defective in the synthesis of the global regulator GacS, which regulates HCN synthesis, showed no aphicidal activity. Direct application of potassium cyanide caused mortality of green peach aphid nymphs. These results indicate that HCN production by a plant probiotic is involved in preventing insect growth.


Assuntos
Afídeos/efeitos dos fármacos , Cianeto de Hidrogênio/farmacologia , Inseticidas/farmacologia , Pseudomonas chlororaphis/metabolismo , Animais , Cianeto de Hidrogênio/metabolismo , Inseticidas/metabolismo
5.
Pediatr Neurol ; 86: 33-41, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30075875

RESUMO

OBJECTIVE: We aimed to evaluate and compare the status epilepticus treatment pathways used by pediatric status epilepticus research group (pSERG) hospitals in the United States and the American Epilepsy Society (AES) status epilepticus guideline. METHODS: We undertook a descriptive analysis of recommended timing, dosing, and medication choices in 10 pSERG hospitals' status epilepticus treatment pathways. RESULTS: One pathway matched the timeline in the AES guideline; nine pathways described more rapid timings. All pathways matched the guideline's stabilization phase in timing and five suggested that first-line benzodiazepine (BZD) be administered within this period. For second-line therapy timing (initiation of a non-BZD antiepileptic drug within 20 to 40 minutes), one pathway matched the guideline; nine initiated the antiepileptic drug earlier (median 10 [range five to 15] minutes). Third-line therapy timings matched the AES guideline (40 minutes) in two pathways; eight suggested earlier timing (median 20 [range 15 to 30] minutes). The first-line BZD recommended in all hospitals was intravenous lorazepam; alternatives included intramuscular midazolam or rectal diazepam. In second-line therapy, nine pathways recommended fosphenytoin. For third-line therapy, eight pathways recommended additional boluses of second-line medications; most commonly phenobarbital. Two pathways suggested escalation to third-line medication; most commonly midazolam. We found variance in dosing for the following medications: midazolam as first-line therapy, fosphenytoin, and levetiracetam as second-line therapy, and phenobarbital as third-line therapy medications. CONCLUSIONS: The pSERG hospitals status epilepticus pathways are consistent with the AES status epilepticus guideline in regard to the choice of medications, but generally recommend more rapid escalation in therapy than the guideline.


Assuntos
Anticonvulsivantes/administração & dosagem , Tratamento de Emergência , Hospitalização , Estado Epiléptico/terapia , Adolescente , Criança , Pré-Escolar , Esquema de Medicação , Hospitais Pediátricos , Humanos , Lactente , Guias de Prática Clínica como Assunto , Sociedades Médicas , Estados Unidos
6.
Mol Cell Neurosci ; 92: 93-103, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30064010

RESUMO

Excitotoxicity caused by excessive stimulation of glutamate receptors, resulting in pathologically increased Ca2+-concentrations, is a decisive factor in neurodegenerative diseases. We investigated long-term changes in synaptic contents of AMPA receptor subunits that play important roles in calcium regulation in chronic epilepsy. Such plastic changes may be either adaptive or detrimental. We used a kainic acid (KA)-based rat model of chronic temporal lobe epilepsy (TLE). Using hippocampal synaptosomes, we found significant reductions in the concentration of the AMPA receptor subunits GluA1 and GluA2, and the NMDA receptor subunit NR2B. The relative size of GluA1 and GluA2 reductions were almost identical, at 28% and 27%, respectively. In order to determine whether the synaptic reduction of the AMPA receptor subunits actually reflected the pool of receptors present along the postsynaptic density (PSD), as opposed to cytoplasmic or extrasynaptic pools, we performed postembedding immunogold electron microscopy (EM) of GluA1 and GluA2 in Schaffer collateral synapses in the hippocampal CA1 area. We found significant reductions, at 32% and 52% of GluA1 and GluA2 subunits, respectively, along the PSD, indicating that these synapses undergo lasting changes in glutamatergic neurotransmission during chronic TLE. When compared to the overall concentration and composition of AMPA receptors expressed in the brain, there was a relative increase in GluA2-lacking AMPA receptor subunits following chronic epilepsy. These changes in synaptic AMPA receptor subunits may possibly contribute to further aggravate the excitotoxic vulnerability of the neurons as well as have significant implications for hippocampal cognitive functions.


Assuntos
Epilepsia do Lobo Temporal/metabolismo , Receptores de AMPA/metabolismo , Sinapses/metabolismo , Animais , Epilepsia do Lobo Temporal/etiologia , Potenciais Pós-Sinápticos Excitadores , Hipocampo/metabolismo , Ácido Caínico/toxicidade , Masculino , Ratos , Ratos Sprague-Dawley , Receptores de AMPA/genética , Sinapses/fisiologia , Sinapses/ultraestrutura
7.
Environ Toxicol Chem ; 37(10): 2619-2632, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29978493

RESUMO

The impact of copper oxide nanoparticles (CuONPs) on crop production is dependent on the biogeochemistry of Cu in the rooting zone of the plant. The present study addressed the metabolites in wheat root exudates that increased dissolution of CuONPs and whether solubility correlated with Cu uptake into the plant. Bread wheat (Triticum aestivum cv. Dolores) was grown for 10 d with 0 to 300 mg Cu/kg as CuONPs in sand, a matrix deficient in Fe, Zn, Mn, and Cu for optimum plant growth. Increased NP doses enhanced root exudation, including the Cu-complexing phytosiderophore, 2'-deoxymugineic acid (DMA), and corresponded to greater dissolution of the CuONPs. Toxicity, observed as reduced root elongation, was attributable to a combination of CuONPs and dissolved Cu complexes. Geochemical modeling predicted that the majority of the solution phase Cu was complexed with citrate at low dosing or DMA at higher dosing. Altered biogeochemistry within the rhizosphere correlated with bio-responses via exudate type, quantity, and metal uptake. Exposure of wheat to CuONPs led to dose-dependent decreases in Fe, Ca, Mg, Mn, and K in roots and shoots. The present study is relevant to growth of a commercially important crop, wheat, in the presence of CuONPs as a fertilizer, fungicide, or pollutant. Environ Toxicol Chem 2018;37:2619-2632. © 2018 SETAC.


Assuntos
Cobre/toxicidade , Exsudatos de Plantas/metabolismo , Raízes de Plantas/metabolismo , Rizosfera , Dióxido de Silício/química , Disponibilidade Biológica , Carbono/análise , Metaboloma , Nanopartículas/toxicidade , Compostos Orgânicos/análise , Raízes de Plantas/efeitos dos fármacos , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Porosidade , Análise de Componente Principal , Solubilidade , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimento
8.
Plant Pathol J ; 34(3): 241-249, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29887780

RESUMO

Commercial biocontrol of microbial plant diseases and plant pests, such as nematodes, requires field-effective formulations. The isolate Pseudomonas chlororaphis O6 is a Gram-negative bacterium that controls microbial plant pathogens both directly and indirectly. This bacterium also has nematocidal activity. In this study, we report on the efficacy of a wettable powder-type formulation of P. chlororaphis O6. Culturable bacteria in the formulated product were retained at above 1 × 108 colony forming units/g after storage of the powder at 25 °C for six months. Foliar application of the diluted formulated product controlled leaf blight and gray mold in tomato. The product also displayed preventative and curative controls for root-knot nematode (Meloidogyne spp.) in tomato. Under laboratory conditions and for commercially grown melon, the control was at levels comparable to that of a standard commercial chemical nematicide. The results indicated that the wettable powder formulation product of P. chlororaphis O6 can be used for control of plant microbial pathogens and root-knot nematodes.

9.
Epilepsia Open ; 3(2): 213-223, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29881800

RESUMO

Objective: Sympathetic predominance and ventricular repolarization abnormalities represent epilepsy-associated cardiac alterations and may underlie seizure-induced ventricular arrhythmias. Myocardial ion channel and electrical remodeling have been described early in epilepsy development and may contribute to ventricular repolarization abnormalities and excitability. Using the pilocarpine-induced acquired epilepsy model we sought to examine whether altered myocardial ion channel levels and electrophysiological changes also occur in animals with long-standing epilepsy. Methods: We examined myocardial adrenergic receptor and ion channel protein levels of epileptic and age-matched sham rats (9-20 months old) using western blotting. Cardiac electrical properties were examined using optical mapping ex vivo and electrophysiology in vivo. We investigated the propensity for ventricular tachycardia (VT) and the effects of ß-adrenergic blockade on ventricular electrical properties and excitability in vivo. Results: In animals with long-standing epilepsy, we observed decreased myocardial voltage-gated K+ channels Kv4.2 and Kv4.3, which are known to underlie early ventricular repolarization in rodents. Decreased ß1 and increased α1A adrenergic receptor protein levels occurred in the myocardium of chronically epileptic animals consistent with elevated sympathetic tone. These animals exhibited many cardiac electrophysiological abnormalities, represented by longer QRS and corrected QT (QTc) intervals in vivo, slower conduction velocity ex vivo, and stimulation-induced VT. Administration of a ß-adrenergic antagonist late in epilepsy was beneficial, as the therapy shortened the QTc interval and decreased stimulation-induced VT. Significance: Our findings demonstrate that myocardial ion channel remodeling and sympathetic predominance, risk factors for increased ventricular excitability and arrhythmias, persist in chronic epilepsy. The beneficial effects of ß-adrenergic antagonist treatment late in the course of epilepsy suggest that attenuating elevated sympathetic tone may represent a therapeutic target for ameliorating epilepsy-associated cardiac morbidity.

10.
Mol Plant Pathol ; 19(10): 2349-2359, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29676842

RESUMO

Many root-colonizing microbes are multifaceted in traits that improve plant health. Although isolates designated as biological control agents directly reduce pathogen growth, many exert additional beneficial features that parallel changes induced in animal and other hosts by health-promoting microbes termed probiotics. Both animal and plant probiotics cause direct antagonism of pathogens and induce systemic immunity in the host to pathogens and other stresses. They also alter host development and improve host nutrition. The probiotic root-colonizing pseudomonads are generalists in terms of plant hosts, soil habitats and the array of stress responses that are ameliorated in the plant. This article illustrates how the probiotic pseudomonads, nurtured by the carbon (C) and nitrogen (N) sources released by the plant in root exudates, form protective biofilms on the root surface and produce the metabolites or enzymes to boost plant health. The findings reveal the multifunctional nature of many of the microbial metabolites in the plant-probiotic interplay. The beneficial effects of probiotics on plant function can contribute to sustainable yield and quality in agricultural production.


Assuntos
Probióticos , Rizosfera , Biofilmes/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Microbiologia do Solo
11.
Neurocrit Care ; 29(2): 171-179, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29582225

RESUMO

BACKGROUND: Functional neurologic outcome for children with refractory and super-refractory status epilepticus has not been well defined. METHODS: Retrospective chart review including children age 0-17 years who received pentobarbital infusion from 2003 to 2016 for status epilepticus. Outcomes were defined in terms of mortality, need for new medical technology assistance at hospital discharge and functional neurologic outcome determined by pediatric cerebral performance category score (PCPC). Potential patient characteristics associated with functional neurologic outcome including age, sex, ethnicity, etiology of the status epilepticus, and duration of pentobarbital infusion were evaluated. RESULTS: Forty children met inclusion criteria. In-hospital mortality was 30% (12/40). Of survivors, 21% (6/28) returned to baseline PCPC while half (14/28) declined in function ≥ 2 PCPC categories at hospital discharge. 25% (7/28) of survivors required tracheostomy and 27% (7/26) required new gastrostomy. Seizures persisted at discharge for most patients with new onset status epilepticus while the majority of patients with known epilepsy returned to baseline seizure frequency. Etiology (p = 0.015), PCPC at admission (p = 0.0006), new tracheostomy (p = 0.012), and new gastrostomy tube (p = 0.012) were associated with increase in PCPC score ≥ 2 categories in univariable analysis. Duration of pentobarbital infusion (p = 0.005) and length of hospital stay (p = 0.056) were longer in patients who demonstrated significant decline in neurologic function. None of these variables maintained statistical significance when multiple logistic regression model adjusting for PCPC score at admission was applied. At long-term follow-up, 36% (8/22) of children demonstrated improvement in PCPC compared to discharge and 23% (5/22) showed deterioration including three additional deaths. CONCLUSIONS: Mortality in this population was high. The majority of children experienced some degree of disability at discharge. Despite prolonged pentobarbital infusion, there were cases of survival with good neurologic outcome.


Assuntos
Epilepsia Resistente a Medicamentos/tratamento farmacológico , Moduladores GABAérgicos/farmacologia , Pentobarbital/farmacologia , Estado Epiléptico/tratamento farmacológico , Adolescente , Criança , Pré-Escolar , Epilepsia Resistente a Medicamentos/mortalidade , Epilepsia Resistente a Medicamentos/cirurgia , Feminino , Seguimentos , Moduladores GABAérgicos/administração & dosagem , Mortalidade Hospitalar , Humanos , Lactente , Unidades de Terapia Intensiva Pediátrica , Masculino , Pentobarbital/administração & dosagem , Estudos Retrospectivos , Estado Epiléptico/mortalidade , Estado Epiléptico/patologia , Estado Epiléptico/cirurgia
12.
Mol Neurobiol ; 55(9): 7500-7511, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29427087

RESUMO

Neuroinflammation is consistently found in many neurological disorders, but whether or not the inflammatory response independently affects neuronal network properties is poorly understood. Here, we report that intracerebroventricular injection of the prototypical inflammatory molecule lipopolysaccharide (LPS) in rats triggered a strong and long-lasting inflammatory response in hippocampal microglia associated with a concomitant upregulation of Toll-like receptor (TLR4) in pyramidal and hilar neurons. This, in turn, was associated with a significant reduction of the dendritic hyperpolarization-activated cyclic AMP-gated channel type 1 (HCN1) protein level while Kv4.2 channels were unaltered as assessed by western blot. Immunohistochemistry confirmed the HCN1 decrease in CA1 pyramidal neurons and showed that these changes were associated with a reduction of TRIP8b, an auxiliary subunit for HCN channels implicated in channel subcellular localization and trafficking. At the physiological level, this effect translated into a 50% decrease in HCN1-mediated currents (Ih) measured in the distal dendrites of hippocampal CA1 pyramidal cells. At the functional level, the band-pass-filtering properties of dendrites in the theta frequency range (4-12 Hz) and their temporal summation properties were compromised. We conclude that neuroinflammation can independently trigger an acquired channelopathy in CA1 pyramidal cell dendrites that alters their integrative properties. By directly changing cellular function, this phenomenon may participate in the phenotypic expression of various brain diseases.


Assuntos
Hipocampo/patologia , Inflamação/patologia , Células Piramidais/patologia , Animais , Dendritos/metabolismo , Regulação para Baixo , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Lipopolissacarídeos , Masculino , Proteínas de Membrana/metabolismo , Microglia/metabolismo , Microglia/patologia , Canais de Potássio/metabolismo , Células Piramidais/metabolismo , Ratos Sprague-Dawley , Fatores de Tempo , Receptor 4 Toll-Like/metabolismo
13.
Plant Pathol J ; 34(1): 35-43, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29422786

RESUMO

Root-knot nematodes (Meloidogyne spp.) are parasites that attack many field crops and orchard trees, and affect both the quantity and quality of the products. A root-colonizing bacterium, Pseudomonas chlororaphis O6, possesses beneficial traits including strong nematicidal activity. To determine the molecular mechanisms involved in the nematicidal activity of P. chlororaphis O6, we constructed two mutants; one lacking hydrogen cyanide production, and a second lacking an insecticidal toxin, FitD. Root drenching with wild-type P. chlororaphis O6 cells caused juvenile mortality in vitro and in planta. Efficacy was not altered in the fitD mutant compared to the wild-type but was reduced in both bioassays for the mutant lacking hydrogen cyanide production. The reduced number of galls on tomato plants caused by the wild-type strain was comparable to that of a standard chemical nematicide. These findings suggest that hydrogen cyanide-producing root colonizers, such as P. chlororaphis O6, could be formulated as "green" nematicides that are compatible with many crops and offer agricultural sustainability.

14.
Sci Rep ; 8(1): 3568, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29476105

RESUMO

Cortical dysplasia (CD) is a common cause for intractable epilepsy. Hyperactivation of the mechanistic target of rapamycin (mTOR) pathway has been implicated in CD; however, the mechanisms by which mTOR hyperactivation contribute to the epilepsy phenotype remain elusive. Here, we investigated whether constitutive mTOR hyperactivation in the hippocampus is associated with altered voltage-gated ion channel expression in the neuronal subset-specific Pten knockout (NS-Pten KO) mouse model of CD with epilepsy. We found that the protein levels of Kv1.1, but not Kv1.2, Kv1.4, or Kvß2, potassium channel subunits were increased, along with altered Kv1.1 distribution, within the hippocampus of NS-Pten KO mice. The aberrant Kv1.1 protein levels were present in young adult (≥postnatal week 6) but not juvenile (≤postnatal week 4) NS-Pten KO mice. No changes in hippocampal Kv1.1 mRNA levels were found between NS-Pten KO and WT mice. Interestingly, mTOR inhibition with rapamycin treatment at early and late stages of the pathology normalized Kv1.1 protein levels in NS-Pten KO mice to WT levels. Together, these studies demonstrate altered Kv1.1 protein expression in association with mTOR hyperactivation in NS-Pten KO mice and suggest a role for mTOR signaling in the modulation of voltage-gated ion channel expression in this model.


Assuntos
Epilepsia/genética , Canal de Potássio Kv1.1/genética , Malformações do Desenvolvimento Cortical/genética , PTEN Fosfo-Hidrolase/genética , Serina-Treonina Quinases TOR/genética , Animais , Modelos Animais de Doenças , Epilepsia/complicações , Epilepsia/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Canal de Potássio Kv1.2/genética , Canal de Potássio Kv1.4/genética , Malformações do Desenvolvimento Cortical/complicações , Malformações do Desenvolvimento Cortical/patologia , Camundongos , Camundongos Knockout , Transdução de Sinais/efeitos dos fármacos , Sirolimo/administração & dosagem , Serina-Treonina Quinases TOR/antagonistas & inibidores
15.
J Agric Food Chem ; 66(26): 6513-6524, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-28481096

RESUMO

As the world population increases, strategies for sustainable agriculture are needed to fulfill the global need for plants for food and other commercial products. Nanoparticle formulations are likely to be part of the developing strategies. CuO and ZnO nanoparticles (NPs) offer potential as fertilizers, as they provide bioavailable essential metals, and as pesticides, because of dose-dependent toxicity. Effects of these metal oxide NPs on rhizosphere functions are the focus of this review. These NPs at doses of ≥10 mg metal/kg change the production of key metabolites involved in plant protection in a root-associated microbe, Pseudomonas chlororaphis O6. Altered synthesis occurs in the microbe for phenazines, which function in plant resistance to pathogens, the pyoverdine-like siderophore that enhances Fe bioavailability in the rhizosphere and indole-3-acetic acid affecting plant growth. In wheat seedlings, reprogramming of root morphology involves increases in root hair proliferation (CuO NPs) and lateral root formation (ZnO NPs). Systemic changes in wheat shoot gene expression point to altered regulation for metal stress resilience as well as the potential for enhanced survival under stress commonly encountered in the field. These responses to the NPs cross kingdoms involving the bacteria, fungi, and plants in the rhizosphere. Our challenge is to learn how to understand the value of these potential changes and successfully formulate the NPs for optimal activity in the rhizosphere of crop plants. These formulations may be integrated into developing practices to ensure the sustainability of crop production.


Assuntos
Cobre/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Óxido de Zinco/farmacologia , Cobre/química , Produção Agrícola , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Fertilizantes/análise , Nanopartículas Metálicas/química , Microbiologia do Solo , Óxido de Zinco/química
16.
J Agric Food Chem ; 66(26): 6619-6627, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-28926236

RESUMO

Plants exist with a consortium of microbes that influence plant health, including responses to biotic and abiotic stress. While nanoparticle (NP)-plant interactions are increasingly studied, the effect of NPs on the plant microbiome is less researched. Here a root-mimetic hollow fiber membrane (HFM) is presented for generating biofilms of plant-associated microbes nurtured by artificial root exudates (AREs) to correlate exudate composition with biofilm formation and response to NPs. Two microbial isolates from field-grown wheat, a bacillus endophyte and a pseudomonad root surface colonizer, were examined on HFMs fed with AREs varying in N and C composition. Bacterial morphology and biofilm architecture were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and responses to CuO and ZnO NP challenges of 300 mg/L evaluated. The bacillus isolate sparsely colonized the HFM. In contrast, the pseudomonad formed robust biofilms within 3 days. Dependent on nutrient sources, the biofilm cells produced extensive extracellular polymeric substances (EPS) and large intracellular granules. Pseudomonad biofilms were minimally affected by ZnO NPs. CuO NPs, when introduced before biofilm maturation, strongly reduced biofilm formation. The findings demonstrate the utility of the HFM root-mimetic to study rhizoexudate influence on biofilms of root-colonizing microbes but without active plant metabolism. The results will allow better understanding of how microbe-rhizoexudate-NP interactions affect microbial and plant health.


Assuntos
Biofilmes/efeitos dos fármacos , Cobre/farmacologia , Nanopartículas Metálicas/análise , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Óxido de Zinco/farmacologia , Cobre/análise , Exsudatos de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Triticum/efeitos dos fármacos , Triticum/metabolismo , Triticum/microbiologia , Óxido de Zinco/análise
17.
Mol Plant Pathol ; 19(5): 1257-1266, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28862813

RESUMO

The Gac/Rsm network regulates, at the transcriptional level, many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays, followed by specific growth studies and mutational analysis, to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate Pseudomonas chlororaphis O6. The growth of a gacS mutant was decreased significantly relative to that of the wild-type on ornithine and arginine, and on the precursor of these amino acids, N-acetyl-l-glutamic acid. The gacS mutant also showed reduced production of polyamines. Expression of the genes encoding arginine decarboxylase (speA) and ornithine decarboxylases (speC) was controlled at the transcriptional level by the GacS sensor of P. chlororaphis O6. Polyamine production was reduced in the speC mutant, and was eliminated in the speAspeC mutant. The addition of exogenous polyamines to the speAspeC mutant restored the in vitro growth inhibition of two fungal pathogens, as well as the secretion of three biological control-related factors: pyrrolnitrin, protease and siderophore. These results extend our knowledge of the regulation by the Gac/Rsm network in a biocontrol pseudomonad to include polyamine synthesis. Collectively, our studies demonstrate that bacterial polyamines act as important regulators of bacterial cell growth and biocontrol potential.


Assuntos
Proteínas de Bactérias/metabolismo , Poliaminas/metabolismo , Pseudomonas chlororaphis/crescimento & desenvolvimento , Pseudomonas chlororaphis/metabolismo , Proteínas de Bactérias/genética , Vias Biossintéticas/genética , Regulação Bacteriana da Expressão Gênica , Mutação/genética , Poliaminas/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Especificidade por Substrato , Transcrição Genética
18.
Sci Rep ; 7(1): 8451, 2017 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-28814801

RESUMO

Angelman syndrome (AS) is a genetic neurodevelopmental disorder, most commonly caused by deletion or mutation of the maternal allele of the UBE3A gene, with behavioral phenotypes and seizures as key features. Currently no treatment is available, and therapeutics are often ineffective in controlling AS-associated seizures. Previous publications using the Ube3a maternal deletion model have shown behavioral and seizure susceptibility phenotypes, however findings have been variable and merit characterization of electroencephalographic (EEG) activity. In this study, we extend previous studies comparing the effect of genetic background on the AS phenotype by investigating the behavioral profile, EEG activity, and seizure threshold. AS C57BL/6J mice displayed robust behavioral impairments, spontaneous EEG polyspikes, and increased cortical and hippocampal power primarily driven by delta and theta frequencies. AS 129 mice performed poorly on wire hang and contextual fear conditioning and exhibited a lower seizure threshold and altered spectral power. AS F1 hybrid mice (C57BL/6J × 129) showed milder behavioral impairments, infrequent EEG polyspikes, and fewer spectral power alterations. These findings indicate the effect of common genetic backgrounds on the Ube3a maternal deletion behavioral, EEG, and seizure threshold phenotypes. Our results will inform future studies on the optimal strain for evaluating therapeutics with different AS-like phenotypes.


Assuntos
Síndrome de Angelman/metabolismo , Modelos Animais de Doenças , Convulsões/metabolismo , Ubiquitina-Proteína Ligases/deficiência , Síndrome de Angelman/genética , Síndrome de Angelman/fisiopatologia , Animais , Eletroencefalografia , Medo/fisiologia , Feminino , Masculino , Aprendizagem em Labirinto/fisiologia , Memória/fisiologia , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora/fisiologia , Fenótipo , Convulsões/genética , Convulsões/fisiopatologia , Especificidade da Espécie , Ubiquitina-Proteína Ligases/genética
19.
Hippocampus ; 27(11): 1168-1177, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28686803

RESUMO

Synaptotagmin 1 is a presynaptic calcium sensor, regulating SNARE-mediated vesicle exocytosis of transmitter. Increasing evidence indicate roles of SNARE proteins in postsynaptic glutamate receptor trafficking. However, a possible postsynaptic expression of synaptotagmin 1 has not been demonstrated previously. Here, we used postembedding immunogold electron microscopy to determine the subsynaptic localization of synaptotagmin 1 in rat hippocampal CA1 Schaffer collateral synapses. We report for the first time that synaptotagmin 1 is present in rat hippocampal postsynaptic spines, both on cytoplasmic vesicles and at the postsynaptic density. We further investigated whether postsynaptic synaptotagmin 1 is regulated during synaptic plasticity. In a rat model of chronic temporal lobe epilepsy, we found that presynaptic and postsynaptic concentrations of the protein are reduced compared to control animals. This downregulation may possibly be an adaptive measure to decrease both presynaptic and postsynaptic calcium sensitivity in excitotoxic conditions.


Assuntos
Vesículas Citoplasmáticas/metabolismo , Espinhas Dendríticas/metabolismo , Hipocampo/metabolismo , Densidade Pós-Sináptica/metabolismo , Sinaptotagmina I/metabolismo , Animais , Células Cultivadas , Doença Crônica , Vesículas Citoplasmáticas/ultraestrutura , Espinhas Dendríticas/ultraestrutura , Modelos Animais de Doenças , Regulação para Baixo , Epilepsia do Lobo Temporal/metabolismo , Epilepsia do Lobo Temporal/patologia , Hipocampo/ultraestrutura , Imuno-Histoquímica , Ácido Caínico , Masculino , Camundongos Knockout , Microscopia Eletrônica , Densidade Pós-Sináptica/ultraestrutura , Terminações Pré-Sinápticas/metabolismo , Terminações Pré-Sinápticas/ultraestrutura , Ratos Sprague-Dawley , Ratos Wistar , Sinaptotagmina I/deficiência , Sinaptotagmina I/genética
20.
Int J Mol Sci ; 18(7)2017 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-28704930

RESUMO

Mitochondrial dysfunction plays a central role in the neuropathology associated with status epilepticus (SE) and is implicated in the development of epilepsy. While excitotoxic mechanisms are well-known mediators affecting mitochondrial health following SE, whether hyperactivation of poly(ADP-ribose) polymerase-1 (PARP-1) also contributes to SE-induced mitochondrial dysfunction remains to be examined. Here we first evaluated the temporal evolution of poly-ADP-ribosylated protein levels in hippocampus following kainic acid-induced SE as a marker for PARP-1 activity, and found that PARP-1 was hyperactive at 24 h following SE. We evaluated oxidative metabolism and found decreased NAD⁺ levels by enzymatic cycling, and impaired NAD⁺-dependent mitochondrial respiration as measured by polarography at 24 h following SE. Stereological estimation showed significant cell loss in the hippocampal CA1 and CA3 subregions 72 h following SE. PARP-1 inhibition using N-(6-Oxo-5,6-dihydro-phenanthridin-2-yl)- N,N-dimethylacetamide (PJ-34) in vivo administration was associated with preserved NAD⁺ levels and NAD⁺-dependent mitochondrial respiration, and improved CA1 neuronal survival. These findings suggest that PARP-1 hyperactivation contributes to SE-associated mitochondrial dysfunction and CA1 hippocampal damage. The deleterious effects of PARP-1 hyperactivation on mitochondrial respiration are in part mediated through intracellular NAD⁺ depletion. Therefore, modulating PARP-1 activity may represent a potential therapeutic target to preserve intracellular energetics and mitochondrial function following SE.


Assuntos
Hipocampo/metabolismo , Hipocampo/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Neurônios/metabolismo , Neurônios/patologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Estado Epiléptico/metabolismo , Estado Epiléptico/patologia , Animais , Western Blotting , Eletroencefalografia , Ratos , Ratos Sprague-Dawley
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