Functional analysis of a rice 12-oxo-phytodienoic acid reductase gene (OsOPR1) involved in Cd stress tolerance.

BACKGROUND: The accumulation of cadmium (Cd) in plants may compromise the growth and development of plants, thereby endangering human health through the food chain. Understanding how plants respond to Cd is important for breeding low-Cd rice cultivars. METHODS: In this study, the functions of 12-oxo-phytodienoic acid reductase 1 (OsOPR1) were predicted through bioinformatics analysis. The expression levels of OsOPR1 under Cd stress were analyzed by using qRT-PCR. Then, the role that OsOPR1 gene plays in Cd tolerance was studied in Cd-sensitive yeast strain (ycf1), and the Cd concentration of transgenic yeast was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Bioinformatics analysis revealed that OsOPR1 was a protein with an Old yellow enzyme-like FMN (OYE_like_FMN) domain, and the cis-acting elements which regulate hormone synthesis or responding abiotic stress were abundant in the promoter region, which suggested that OsOPR1 may exhibit multifaceted biological functions. The expression pattern analysis showed that the expression levels of OsOPR1 were induced by Cd stress both in roots and roots of rice plants. However, the induced expression of OsOPR1 by Cd was more significant in the roots compared to that in roots. In addition, the overexpression of OsOPR1 improved the Cd tolerance of yeast cells by affecting the expression of antioxidant enzyme related genes and reducing Cd content in yeast cells. CONCLUSION: Overall, these results suggested that OsOPR1 is a Cd-responsive gene and may has a potential for breeding low-Cd or Cd-tolerant rice cultivars and for phytoremediation of Cd-contaminated in farmland.

OsHIPP17 is involved in regulating the tolerance of rice to copper stress.

Introduction: Heavy metal-associated isoprenylated plant proteins (HIPPs) play vital roles in metal absorption, transport and accumulation in plants. However, so far, only several plant HIPPs have been functionally analyzed. In this study, a novel HIPP member OsHIPP17, which was involved in the tolerance to copper (Cu) was functionally characterized. Methods: In this study, qRT-PCR, Yeast transgenic technology, Plant transgenic technology, ICP-MS and so on were used for research. Results: OsHIPP17 protein was targeted to the nucleus. The Cu concentration reached 0.45 mg/g dry weight due to the overexpression of OsHIPP17 in yeast cells. Meanwhile, the overexpression of OsHIPP17 resulted in the compromised growth of Arabidopsis thaliana (Arabidopsis) under Cu stress. The root length of Oshipp17 mutant lines was also significantly reduced by 16.74- 24.36% under 25 mM Cu stress. The roots of Oshipp17 rice mutant showed increased Cu concentration by 7.25%-23.32%. Meanwhile, knockout of OsHIPP17 decreased the expression levels of OsATX1, OsZIP1, OsCOPT5 or OsHMA5, and increased the expression levels of OsCOPT1 or OsHMA4. Antioxidant enzyme activity was also reduced in rice due to the knockout of OsHIPP17. Moreover, the expression levels of cytokinin-related genes in plants under Cu stress were also affected by overexpression or knockout of OsHIPP17. Discussion: These results implied that OsHIPP17 might play a role in plant Cu toxic response by affecting the expression of Cu transport genes or cytokinin-related genes. Simultaneously, our work may shed light on the underlying mechanism of how heavy metals affect the plant growth and provide a novel rice genetic source for phytoremediation of heavy metal-contaminated soil.

7,8-Dihydroxycoumarin Alleviates Synaptic Loss by Activated PI3K-Akt-CREB-BDNF Signaling in Alzheimer's Disease Model Mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is clinically characterized by the impairment of memory and cognition. Accumulation of ß-amyloid (Aß) in the brain is considered as a key process in the development of AD because it impairs the synapses' function to impair memory formation. Recent research studies have indicated that a group of edible plant-derived Thymelaeaceae compounds known as coumarin may exert particularly powerful actions on alleviating learning and memory impairment. 7,8-Dithydroxycoumarin (7,8-DHC), a bioactive component of coumarin derived from Thymelaeaceae, showed its function in neuroprotection before. In this study, we found that 7,8-DHC was able to mitigate Aß accumulation via reducing the level of BACE1 and increasing the level of ADAM17 and ADAM10. More importantly, we found that 7,8-DHC could mitigate memory impairment, promote the dendrite branch density, and increase synaptic protein expression via activating PI3K-Akt-CREB-BDNF signaling. Hence, these results suggested that 7,8-DHC represented a novel bioactive therapeutic agent in mitigating Aß deposition and synaptic loss in the process of treating AD.

Platycladus orientalis seed extract as a potential triple reuptake MAO inhibitor rescue depression phenotype through restoring monoamine neurotransmitters.

ETHNOPHARMACOLOGY RELEVANCE: Platycladus orientalis seeds are recorded in traditional Chinese medicine (TCM) formulations for modulation of mood and physical activity in "Shen Nong Ben Cao Jing" and "Compendium of Materia Medica" and so on. Recently, we identified its extracting components and looked for the potentials in treatment for depression by improving the function of monoamine neurotransmitters. AIM OF THE STUDY: We investigated the mechanism of action of the seed extracts of P. orientalis (S4) to rescue depressive behavior in a chronic, unpredicted, mild stress (CUMS)-induced model in rats. MATERIALS AND METHODS: We used ultra-fast liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry to analyze the chemical constituents in S4. An assay platform in zebrafish and molecular docking were used to analyze if S4 regulated rest/wake behavior and predict the biological targets which correlated with monoamine neurotransmitters. Depressive-behavior tests (body weight, sucrose preference test, tail-suspension test, forced-swimming test) were carried in the CUMS model. After behavior tests and killing, rat brains were separated into the hippocampus, frontier cortex and dorsal raphe nucleus. The main monoamine neurotransmitters and their metabolite concentrations in these three brain regions were measured by rapid resolution liquid chromatography coupled with triple quadrupole tandem mass spectrometry. RESULTS: Forty-one compounds were identified in S4, including fatty acids, terpenoids, amino acids, plant sterols and flavonoids. S4 could increase the total rest time and decrease the waking activity of zebrafish. S4 showed high correlation with adrenaline agonists, 5-hydroxytryptamine (5-HT) reuptake inhibitors and dopamine agonists. CUMS-group rats, compared with controls, had significantly decreased body weight and preference for sucrose water, whereas the immobility time in the tail-suspension test and forced-swimming test was increased. S4 could significantly rescue the increased levels of 5-HT, noradrenaline and dopamine in the prefrontal cortex and dorsal raphe nucleus. CONCLUSIONS: We demonstrated that S4 was a potential inhibitor of MAO reuptake that could rescue depression in a CUMS-model rats by restoring monoamine neurotransmitters in different encephalic regions.

Complementary Copper-Catalyzed and Electrochemical Aminosulfonylation of O-Homoallyl Benzimidates and N-Alkenyl Amidines with Sodium Sulfinates.

A complementary copper-catalyzed and electrochemical aminosulfonylation of O-homoallyl benzimidates and N-alkenyl amidines with sodium sulfinates was developed. The terminal alkene substrate produced sulfone-containing 1,3-oxazines and tetrahydropyrimidines in the presence of Cu(OAc)2, Ag2CO3, and DPP, and under similar reaction conditions, sulfonylated tetrahydro-1,3-oxazepines were prepared from 1-aryl-substituted O-homoallyl benzimidates in moderate to good yields. For certain electron-rich 1,1-diaryl-substituted alkene substrates, the corresponding tetrahydro-1,3-oxazepines could also be obtained in similar or even higher yields via a green electrochemical technique.

Modulation of the Aß-Peptide-Aggregation Pathway by Active Compounds From Platycladus orientalis Seed Extract in Alzheimer's Disease Models.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by neuronal loss, cognitive impairment, and aphasia. Aggregation of ß-amyloid (Aß) peptide in the brain is considered a key mechanism in the development of AD. In the past 20 years, many compounds have been developed to inhibit Aß aggregation and accelerate its degradation. Platycladus orientalis seed is a traditional Chinese medicine used to enhance intelligence and slow aging. We previously found that Platycladus orientalis seed extract (EPOS) inhibited Aß-peptide aggregation in the hippocampus and reduced cognitive deficits in 5×FAD mice. However, the mechanisms of these effects have not been characterized. To characterize the protective mechanisms of EPOS, we used a transgenic Caenorhabditis elegans CL4176 model to perform Bioactivity-guided identification of active compounds. Four active compounds, comprising communic acid, isocupressic acid, imbricatolic acid, and pinusolide, were identified using 13C-and 1H-NMR spectroscopy. Furthermore, we showed that isocupressic acid inhibited Aß generation by modulating BACE1 activity via the GSK3ß/NF-κB pathway in HEK293-APPsw cells. These findings showed that EPOS reduced cognitive deficits in an AD model via modulation of the Aß peptide aggregation pathway.