RESUMO
Plant A/T-rich protein and zinc-binding protein (PLATZ) transcription factors play important roles in plant growth, development and abiotic stress responses. However, how PLATZ influences plant drought tolerance remains poorly understood. The present study showed that PLATZ4 increased drought tolerance in Arabidopsis thaliana by causing stomatal closure. Transcriptional profiling analysis revealed that PLATZ4 affected the expression of a set of genes involved in water and ion transport, antioxidant metabolism, small peptides and abscisic acid (ABA) signaling. Among these genes, the direct binding of PLATZ4 to the A/T-rich sequences in the plasma membrane intrinsic protein 2;8 (PIP2;8) promoter was identified. PIP2;8 consistently reduced drought tolerance in Arabidopsis through inhibiting stomatal closure. PIP2;8 was localized in the plasma membrane, exhibited water channel activity in Xenopus laevis oocytes and acted epistatically to PLATZ4 in regulating the drought stress response in Arabidopsis. PLATZ4 increased ABA sensitivity through upregulating the expression of ABSCISIC ACID INSENSITIVE 3 (ABI3), ABI4 and ABI5. The transcripts of PLATZ4 were induced to high levels in vegetative seedlings under drought and ABA treatments within 6 and 3 h, respectively. Collectively, these findings reveal that PLATZ4 positively influences plant drought tolerance through regulating the expression of PIP2;8 and genes involved in ABA signaling.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ácido Abscísico/metabolismo , Resistência à Seca , Aquaporina 2/genética , Aquaporina 2/metabolismo , Plantas Geneticamente Modificadas/genética , Secas , Proteínas de Membrana/metabolismo , Membrana Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico/genética , Estômatos de Plantas/fisiologiaRESUMO
This study investigated the protective effects of two polysaccharides (CPA-1 and CPB-2) from Cordyceps cicadae against high fructose/high fat diet (HF/HFD) induced obesity and metabolic disorders in rats. Rats were either fed with normal diet or HF/HFD and treated with CPA-1 and CPB-2 (100 and 300â mg/kg) for 11 weeks. Administration of CPA-1 and CPB-2 significantly and dose dependently reduced body and liver weight, insulin and glucose tolerance, serum insulin and glucose levels. Furthermore, serum and hepatic lipid profiles, liver function enzymes and proinflammatory cytokines (TNF-α, IL-1ß and IL-6) were markedly reduced. Additionally, CPA-1 and CPB-2 treatment alleviated hepatic oxidative stress by reducing lipid peroxidation level (MDA) and upregulating glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities as well as ameliorated histological alterations through the reduction of hepatic lipid accumulation. These results suggested that the polysaccharides from C. cicadae showed protective effects against HF/HFD induced metabolic disturbances and may be considered as a dietary supplement for treating obesity.
Assuntos
Anti-Inflamatórios/farmacologia , Cordyceps/química , Fígado/efeitos dos fármacos , Síndrome Metabólica/tratamento farmacológico , Polissacarídeos/farmacologia , Substâncias Protetoras/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Dieta Hiperlipídica , Fígado/metabolismo , Síndrome Metabólica/induzido quimicamente , Síndrome Metabólica/patologia , Estresse Oxidativo/efeitos dos fármacos , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Substâncias Protetoras/química , Substâncias Protetoras/isolamento & purificação , Ratos , AçúcaresRESUMO
Unfavourable conditions, such as prolonged drought and high salinity, pose a threat to the survival and agricultural yield of plants. The phytohormone ABA plays a key role in the regulation of plant stress adaptation and is often maintained at high levels for extended periods. While much is known about ABA signal perception and activation in the early signalling stage, the molecular mechanism underlying desensitization of ABA signalling remains largely unknown. Here we demonstrate that in the endoplasmic reticulum (ER)-Golgi network, the key regulators of ABA signalling, SnRK2.2/2.3, undergo N-glycosylation, which promotes their redistribution from the nucleus to the peroxisomes in Arabidopsis roots and influences the transcriptional response in the nucleus during prolonged ABA signalling. On the peroxisomal membrane, SnRK2s can interact with glucose-6-phosphate (G6P)/phosphate translocator 1 (GPT1) to maintain NADPH homeostasis through increased activity of the peroxisomal oxidative pentose phosphate pathway (OPPP). The resulting maintenance of NADPH is essential for the modulation of hydrogen peroxide (H2O2) accumulation, thereby relieving ABA-induced root growth inhibition. The subcellular dynamics of SnRK2s, mediated by N-glycosylation suggest that ABA responses transition from transcriptional regulation in the nucleus to metabolic processes in the peroxisomes, aiding plants in adapting to long-term environmental stress.
Assuntos
Ácido Abscísico , Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , NADP , Peroxissomos , Proteínas Serina-Treonina Quinases , Transdução de Sinais , Arabidopsis/metabolismo , Arabidopsis/genética , Peroxissomos/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Glicosilação , Ácido Abscísico/metabolismo , NADP/metabolismo , Peróxido de Hidrogênio/metabolismo , Retículo Endoplasmático/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Núcleo Celular/metabolismo , Complexo de Golgi/metabolismo , Via de Pentose Fosfato , Reguladores de Crescimento de Plantas/metabolismoRESUMO
The exact scales of volume and density of human internal organs were measured synchronously with the intelligentized volum-densimeter, which was made. by ourself. These primary values of normal and diffuse pathologic changes can refer easily and used for the diagnosis in human autopsy of pathology and forensic pathology. It is expectated to be co-operated widely in that the basic values of volume and density will be obtained from all organs of the human body with the population of different races. But up to now, we are still lack these primary values in anthropology and medicine.