Arbuscular mycorrhizal fungus-mediated amelioration of NO2-induced phytotoxicity in tomato.

Atmospheric nitrogen dioxide (NO2) negatively affects plant (crop) growth and development, as well the yield and quality in some regions or environments. Arbuscular mycorrhizal fungus (AMF)-mediated amelioration of NO2-induced plant damage has been reported, but the underlying mechanisms remained unclear. This study explored the beneficial effect of AMF symbiosis on tomato plant responses to NO2 at physiology, biochemistry, and gene expression, with an emphasis on nitrate metabolism, antioxidative defense, and photosynthetic performance. Pot-grown plants were used in the experiments, which were performed in laboratory from February to November 2019. NO2 fumigation with a dose of 10 ± 1 ppm was carried out after 50 d of plant growth, and data were collected following 8 h of fumigation. NO2 fumigation (+NO2) and AMF inoculation (+AMF), alone and especially in combination (NO2 + AMF), increased the gene expression of nitrate- and nitrite reductase, and their enzymatic activity in leaves, such as by 61%, 27%, and 126% for the activity of nitrate reductase, and by 95%, 37%, and 188% for nitrite reductase, respectively, in +NO2, +AMF, and AMF + NO2 plants relative the control (-NO2, -AMF) levels. Following NO2 exposure, +AMF leaves displayed stronger activities of superoxide dismutase, peroxidase and catalase, and higher content of glutathione and ratio of its reduced form to oxidized form, as compared with -AMF ones. Correspondingly, lesser oxidative damage was detected in +AMF than in -AMF plants, as indicated by the contents of H2O2 and malondialdehyde, electrolyte leakage, also by in situ visualization for the formation of H2O2, superoxide anion, and dead cells. The increased antioxidative capacity in +AMF plants was correlated with enhanced expression of antioxidation-related genes. Exposure to NO2 substantially impaired photosynthetic processes in both + AMF and -AMF plants, but an obvious mitigation was observed in the former than in the latter. For example, the total chlorophyll, net photosynthetic rate, stomatal conductance, and ribulose-1,5-bisphosphate carboxylase activity were 18%, 27%, 26%, and 40% higher, respectively, in +AMF than in -AMF plants under NO2 stress. The differential photosynthetic performance was also revealed by chlorophyll fluorescence imaging. We analyzed the expression patterns of some genes related to photosynthesis and carbon metabolisms, and found that all of them exclusively presented a higher expression level in +AMF plants relative to -AMF ones under NO2 stress. Taken together, this study provided evidence that AMF symbiosis played a positively regulatory role in host plant responses to NO2, probably by increasing leaf nitrate metabolism and antioxidative defense, and maintaining the photosynthetic efficiency to some extent, wherein the transcription regulation might be a main target.

Synthesis and antitumor activity of α,ß-unsaturated carbonyl moiety- containing oleanolic acid derivatives targeting PI3K/AKT/mTOR signaling pathway.

Oleanolic acid (OA) and its semi-synthetic derivatives have been reported to have a wide range of biological activities. The introduction of electrophilic Michael acceptor group can increase the reactivity of OA to cellular targets and thus improve the anti-tumor activity. In this work, a series of novel α,ß-unsaturated carbonyl derivatives of OA were designed and synthesized. Their in vitro cytotoxic activity against MCF-7, HepG2 and HeLa cells were tested. Most derivatives exhibited improved cell growth inhibitory activity, especially for 3d with an IC50 of 0.77 µM in MCF-7 cells. Moreover, 3d inhibited the migration of MCF-7 and HeLa cells at the concentration of 4 µM. Flow cytometric analysis revealed that 3d induced cell apoptosis and S phase arrest in a concentration-dependent manner. Western blotting experiment demonstrated that 3d inhibited the phosphorylation of AKT and mTOR. These results suggest that this series of OA derivatives bearing exocyclic methylene ketone pharmacophore are promising anticancer agents as potential PI3K/AKT/mTOR pathway inhibitors.

Ethylene insensitive mutation improves Arabidopsis plant tolerance to NO2 exposure.

Ethylene signaling was addressed, for the first time, in plant responses to nitrogen dioxide (NO2) by comparatively analyzing the performance of Arabidopsis ethylene insensitive 2 (ein2-1) with wild-type (WT) plants. Following NO2 fumigation, severe leaf wilting and chlorosis occurred in WT plants, but much less symptoms were observed in ein2-1. The activities of superoxide dismutase (SOD), peroxidase (PRX) and catalase (CAT) were 39%, 92%, and 11% higher, respectively, in ein2-1 than in WT following NO2 exposure. Although glutathione contents and the ratio of its reduced form (GSH) to oxidized form (GSSG) were decreased by NO2, an obviously alleviated degree was detected in ein2-1 relative to WT. Correspondingly, the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), and electrolyte leakage were 25%, 24%, and 29% lower, respectively, in ein2-1 than in WT. The difference of oxidative stress between two tested genotypes was also revealed by the leaf staining regarding the production and distribution of H2O2, superoxide anion (O2˙-), and cell death. The genes involved in antioxidation or oxidation-reduction processes mostly presented a stronger expression in ein2-1 than in WT under NO2 stress. The photosynthesis-related parameters including chlorophyll and soluble sugar contents, net photosynthetic rate (Pn), and ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity and gene expression, and chlorophyll fluorescence parameters were affected, generally, to a lesser degree in ein2-1 than in WT following NO2 fumigation. The enzymatic activities and gene expressions of invertases mostly displayed a higher level in ein2-1 relative to WT following NO2 fumigation. For example, the activities of cytoplasmic, cell wall and vacuolar invertases were 76%, 26%, and 26% higher, respectively, in ein2-1 than in WT. Together, these data suggest that ethylene signal insensitivity efficiently improves plant tolerance to NO2 exposure, and the possible mechanisms might be correlated with leaf antioxidative defense, photosynthesis-related processes, and sucrose metabolisms.

Orobanone analogues from acid-promoted aromatization rearrangement of curcumol inhibit hypoxia-inducible factor-1 (HIF-1) in cell-based reporter assays.

In this paper, the mechanism of orobanone analogues formation via aromatization rearrangement of curcumol was minutely explored. Aromatization of curcumol with acetone under acidic condition was selected as the model reaction. The formation of a stable aromatic system was the driving force for this reaction. Based on the model reaction, other four new orobanone analogues were prepared through curcumol reacting with different carbonyl compounds. The results showed that the stability of carbocation, which was generated from the carbonyl compounds, and the steric hindrance were main factors affecting the aromatization. We also synthesized the analogue of aromaticane B using compound 2. In vitro anti-proliferative activity of some derivatives were tested by MTT assay. Two derivatives showed weak anti-tumor effect on two cancer cell lines (HepG2 and MCF7) under normoxia. Four orobanone analogue 2, 5, 6 and 9 significantly inhibited hypoxia-induced HIF-1 luciferase reporter activity in HeLa cells with the IC50 values of 13.6, 6.6, 2.4 and 18.2 µM, respectively.

Salicylic acid-altering Arabidopsis plant response to cadmium exposure: Underlying mechanisms affecting antioxidation and photosynthesis-related processes.

Previous studies have demonstrated that the genetic modification of basal salicylic acid (SA) level changed Arabidopsis plant response to cadmium (Cd) stress, but the mechanisms remain evaluated. In this study, Arabidopsis wild type (WT) and its SA-reducing transgenic line nahG (naphthalene hydroxylase G), SA-accumulating mutant snc1 (suppressor of nonexpressor of PR gene, constitutive 1) were exposed to 50 µM Cd2+ for 48 h or 7 d (just for assessing plant growth). The Cd treatment increased the expression levels of SA biosynthesis-related genes leading to enhanced SA accumulations in plant leaves, which was further confirmed by the expression patterns of SA marker genes. Cadmium accumulation was much higher in the Cd-exposed roots than in leaves, but was not affected by SA levels. Exposure to Cd inhibited plant growth of both aerial parts and roots, to a greater degree in snc1, and a lesser extent in nahG as compared with WT. Although Cd treatment increased plant antioxidative capacity, oxidative damage happened, especially to snc1 plants. Photoinhibition occurred in Cd-stressed plants leading to a decrease in photosynthetic activity, with a greater degree in snc1, while a lesser in nahG, as indicated by the changes of several key photosynthetic parameters. We comprehensively analyzed the expression profiles of photosynthesis-related genes, and observed a positive correlation between Cd tolerance and gene expression levels, wherein the transcription levels of two electron transport-related genes and two amylase-encoding genes were all up-regulated in nahG plants after Cd treatment, implying a significance of the related processes in this genotype against Cd stress.

Selenium and Zinc against Aß25-35-Induced Cytotoxicity and Tau Phosphorylation in PC12 Cells and Inhibits γ-cleavage of APP.

Amyloid beta (Aß) is the main component of the amyloid plaques that accumulate in the brains of Alzheimer patients. The present study was conducted to investigate whether the combined treatment with selenium (Se) and zinc (Zn) offers more beneficial effects than that provided by either of them alone in reversing Aß25-35-induced neurotoxicity in PC12 cells. Cells were pretreated with 0.1 µmol/L of Se and Zn for 4 h, after treated with 10 mmol/L Aß25-35 for 24 h. Cells were divided into control and five treated groups, and received either 10 mmol/L Aß25-35,10 mmol/L Aß25-35 + 0.1 µmol/L Se, 10 mmol/L Aß25-35 + 0.1 µmol/L Zn, 10 mmol/LAß25-35 + 0.1 µmol/L Se + 0.1 µmol/L Zn, or 0.1 µmol/L Se + 0.1 µmol/L Zn. The result showed that cell viability was decreased in MTT metabolic rate; LDH release and MDA, H2O2, and NO levels were increased and the GSK-3ß and phosphorylated tau protein level were increased in Aß25-35-treated group (P < 0.05 or P < 0.01), which whole changes were attenuated by Se and Zn and Se combined Zn. In order to evaluate whether the Se and Zn have an effect on processing pathway of amyloid precursor protein (APP), we examined the activity of γ-secretase in primary cultured cortical neuron cells. ELISA analysis showed that Se and Zn could inhibit the activity of γ-secretase. Then we also investigated the effect of Se and Zn on the Aß1-40 concentration and APP-N-terminal fragment expression from APP695 stably transfected Chinese hamster ovary (CHO) cells. APP695 stably transfected CHO cells were treated with 0.1 µmol/L Se and Zn; cells were divided into control and four treated groups, which received either 0.5 M DAPT, 0.1 µmol/L Se, 0.1 µmol/L Zn, or 0.1 µmol/L Se + 0.1 µmol/L Zn. Se and Zn could decrease Aß1-40 production and increase the APP-N-terminal fragment protein expression. These experiments indicate that Se and Zn have a protective effect on AD pathology that a possible mechanism is inhibiting the activity of γ-secretase to decreasing Aß1-40 production further influencing the APP processing. Altogether, our findings may provide a novel therapeutic target to treat AD sufferers.

[Inhibition of the activity of sulfate-reducing bacteria in produced water from oil reservoir by nitrate].

Growth and metabolic activity of sulfate-reducing bacteria (SRB) can result in souring of oil reservoirs, leading to various problems in aspects of environmental pollution and corrosion. Nitrate addition and management of nitrate-reducing bacteria (NRB) offer potential solutions to controlling souring in oil reservoirs. In this paper, a facultive chemolithotrophic NRB, designated as DNB-8, was isolated from the produced fluid of a water-flooded oil reservoir at Daqing oilfield. Then the efficacies and mechanisms of various concentrations of nitrate in combination with DNB-8 in the inhibition of the activity of SRB enriched culture were compared. Results showed that 1.0 mmol x L(-1) of nitrate or 0.45 mmol x L(-1) of nitrite inhibited the sulfate-reducing activity of SRB enrichments; the competitive reduction of nitrate by DNB-8 and the nitrite produced were responsible for the suppression. Besides, the SRB enrichment cultures showed a metabolic pathway of dissimilatory nitrate reduction to ammonium (DNRA) via nitrite. The SRB cultures could possibly alleviate the nitrite inhibition by DNRA when they were subjected to high-strength nitrate.

[Research on degradation of methylene blue by coal bottom ash-microwave irradiation method].

Coal bottom ash is rich in metals and transition metals, and with microwave irradiation these metals can effectively degradate organic matter. Methylene blue degradation by coal bottom ash-microwave irradiation mainly through hydroxyl radicals to degrade organic matter, and metals and rare metals in bottom ash can be used as a catalyst for deep oxidation of organic matter, can reduce processing costs, and reduce environmental pollution. In the present paper the main parameters including the amount of coal bottom ash, H2O2 dosage and time of microwave irradiation were investigated. The UV-visible spectra of methylene blue were determined. The results show that: under coal bottom ash and H2O2 microwave condition the degeneration rate of methylene blue was almost 100%. The dosage of coal ash can accelerate the reaction process, speeding up the degradation of methylene blue. The increase of H2O2 may provide more * OH and speed up the reaction process, but when up to a certain amount, the influence is weakened. The lengthening of microwave time may enhance the reaction temperature, and urge the methylene blue to degrade completely. For 0.125 g x L(-1) of methylene blue, by adding 1.0 g coal bottom ash, 5 mL H2O2 and under mesotherm microwave temperature for 4 min, the methylene blue can be all degradated.

[Removal of bisphenol A and tetrabromobisphenol A membrane by nanofiltration from water source].

The removal efficiency of BPA and TBBPA by nanofiltration membrane Desal 5 DK has been investigated with a lab-scale dead-end filtration module and the role of adsorption of two molecules on membrane was also explored to understand the filtration mechanism. The results showed that the R(obs) of BPA decreased from 89% to 47% as the accumulated adsorption quantity of BPA onto the membrane increased to 30 microg x m(-2). The high BPA concentration in adsorption layer caused the water flux decline especially at high pressure. The high TBBPA rejection of over 95% by Desal 5 DK was obtained due to the molecular weight and molecular structure although the accumulated adsorption quantity of TBBPA reached 50 microg x m(-2). The desorption test showed that the TBBPA could not pass through the membrane for its structure at the 5 x 10(5) Pa, while BPA could diffuse through the membrane and the peak concentration was obtained after 30 mL filtration. The quantity of BPA released from the membrane contributed 30% of the total amount adsorbed by the membrane Desal 5 DK.

Physical Violence Reported by Han and Korean Chinese School Children (II): Cross-Cultural Comparison of Risk Factors / 신경정신의학

OBJECTIVES: The prevalence of child physical violence may differ between cultures. However, it is poorly understood why differences exist. Authors' previous study (Kim et al. 2005) confirmed different prevalence of physical violence existed in Han and Korean Chinese children. This study further investigated the cross-cultural differences in risk factors for violence and its possible linkage with different prevalence between ethnic groups. METHODS: Datas contain responses from 1158 Han and 1145 Korean Chinese children in fourth to sixth grade (aged 10 to 12) from eight ethnic elementary schools in Yanji city of North Eastern China. Demographic variables and attitude toward corporal punishment were compared between violenced and non-violenced children in each ethnic group. Significant variables from bivariate analyis were further used for binary logistic regression analysis to identify best fitting model of risk factors in each group.Additionally risk factors for types of violence (i.e., family violence, peer violence, and violence by teachers) were also examined. RESULTS: Identified common risk factors were boys and younger children. Results form the Han group also revealed single or absent parents, having siblings, and approval of corporal punishment as additional risk factors, while Korean Chinese group included poor economic state. Most consistent and salient risk facor for each type of violence was the experience of other types of violence. CONCLUSION: Current findings are consistent with previously indentified risk factors in the literature. Basically, two ethnic groups had a very similar pattern of risk factors. However, minor differences did exist in additional factors. This may suggest that culturally different mediating factors are responsible for cross-cultural difference in prevalence of child violence.

Association of estrogen receptor 1 intron 1 C/T polymorphism in Korean vitiligo patients.

BACKGROUND: Vitiligo is a common disease characterized by cutaneous white maculae due to loss of melanocytes. It is a polygenic disease, however, the exact pathogenesis of vitiligo is not yet known. The estrogen receptor (ESR) 1 gene was selected as a candidate gene because some researchers treated vitiligo successfully with the steroid-thyroid hormone mixture containing estrogen. Furthermore ESR was expressed in the melanocytes which have an important role in the pigmentation. The polymorphisms of ESR1 gene in vitiligo patients was not reported yet. OBJECTIVE: To determine whether polymorphisms of ESR1 gene were associated with susceptibility to vitiligo patients in Korean population. METHODS: We conducted case-control association study of vitiligo patients (120) and healthy controls (254). Genotypes of ESR1 gene (intron 1 C/T, exon 4 C/G, and exon 8 A/G) were determined by polymerase chain reaction followed by restriction enzyme digestion. RESULTS: Intron 1 T/C allele frequency was significantly different between patients and controls (P = 0.034). Intron 1 T/C genotype distribution (P = 0.021) and allele frequency (P = 0.013) were different between female vitiligo patients and female controls. Intron 1 T/C allele frequency showed significantly difference between generalized type of vitiligo patients and controls (P = 0.044). Genotype distributions and allele frequencies of exon 4 C/G and exon 8 A/G polymorphisms were not different between patients and controls. CONCLUSION: The present study suggests that ESR1 may be a possible risk factor for female or generalized type of vitiligo patients.

Association of angiotensin converting enzyme gene I/D polymorphism of vitiligo in Korean population.

Vitiligo (leukoderma) is an acquired idiopathic hypomelanotic disorder characterized by the circumscribed depigmented patches. Vitiligo is a polygenic disease. The exact pathogenesis is not yet known. The angiotensin converting enzyme (ACE) gene was selected as a candidate gene as ACE plays an important role in the physiology of the vasculature, blood pressure and inflammation, and its relationship with various diseases, including autoimmune diseases, has been widely investigated. The I/D polymorphism of ACE gene in vitiligo patients has not been reported. In this study, we investigated ACE gene polymorphism in 120 vitiligo patients and in 429 healthy volunteers in Korea. The ACE gene genotype distribution (P = 0.032) and allele frequency (P = 0.012) were significantly different between vitiligo patients and healthy controls. This study suggests that the ACE gene polymorphism has a strong association with the development of vitiligo in Korean patients.