Formation of iron plaque on mangrove Kandalar Obovata (SL) root surfaces and its role in cadmium uptake and translocation

In this study, a pot experiment was conducted to investigate the formation of iron plaque under Cd stress and its role in Cd uptake and translocation by mangrove Kandalar. Obovata (S.L.). Results showed:. 1.the Fe in dithionite-citrate-bicarbonate (DCB) extracts increased with an increasing rate of Cd treatments.2.the Cd in DCB extracts and in roots and above-ground tissues significantly increased with an increasing Cd application;3.significant positive correlation between concentration of Cd and Fe in DCB extracts existed (p<0.05); and that4.the proportion of Cd in DCB extracts was significantly lower than that in roots or above-ground tissues (p<0.001).In conclusion, formation of Fe plaque can precipitate Cd on root surfaces and impede its uptake and translocation in Kandalar. Obovata (S.L.). However, in comparison with root tissues, Fe plaque is of little significance. It is the mangrove root tissue that acts as the main buffer to Cd uptake and translocation. ? 2013 Elsevier Ltd

Phosphorus and cadmium interactions in Kandelia obovata (S L) in relation to cadmium tolerance

National Important Scientific Research Program of China [2013CB956504]; National Natural Science Foundation of China [31170471, 30970527]This study focused on the cadmium (Cd) tolerance of mangroves with application of phosphate (P) in order to explore whether exogenous P can alleviate Cd stress on these intertidal species. Kandelia obovata (S. L.) seedlings were cultivated in rhizoboxes under different levels of Cd and P concentrations. The speciation distributions of Cd in the rhizosphere and non-rhizosphere sediments were examined by sequential extraction procedures; organic acid in plant tissues and soil solution was measured by high-performance liquid chromatography; Cd and P accumulation in the plants was also determined. Results showed that considerable differences existed in Cd speciation distributions between rhizosphere and non-rhizosphere sediments. Root activity influenced the dynamics of Cd, P application increased the organic acid content in root tissues, P also increased Cd accumulation in roots whilst lowering Cd translocation from root to the above-ground tissues, and a significant positive correlation was found between Cd and P in roots (r = 0.905). It is postulated that Cd detoxification of K. obovata (S. L.) is associated with higher Cd immobilization in the presence of higher P and organic acid contents in root tissue

Conditional Granger Causality Analysis of Effective Connectivity during Motor Imagery and Motor Execution in Stroke Patients

Aims. Motor imagery has emerged as a promising technique for the improvement of motor function following stroke, but the mechanism of functional network reorganization in patients during this process remains unclear. The aim of this study is to evaluate the cortical motor network patterns of effective connectivity in stroke patients. Methods. Ten stroke patients with right hand hemiplegia and ten normal control subjects were recruited. We applied conditional Granger causality analysis (CGCA) to explore and compare the functional connectivity between motor execution and motor imagery. Results. Compared with the normal controls, the patient group showed lower effective connectivity to the primary motor cortex (M1), the premotor cortex (PMC), and the supplementary motor area (SMA) in the damaged hemisphere but stronger effective connectivity to the ipsilesional PMC and M1 in the intact hemisphere during motor execution. There were tighter connections in the cortical motor network in the patients than in the controls during motor imagery, and the patients showed more effective connectivity in the intact hemisphere. Conclusions. The increase in effective connectivity suggests that motor imagery enhances core corticocortical interactions, promotes internal interaction in damaged hemispheres in stroke patients, and may facilitate recovery of motor function

Modeling of flexible metal wheel for pressurized lunar rover and traction performance prediction

The pressurized lunar rover has become one of the most important equipment in lunar exploration and resource utilization missions. On the terrain of soft lunar regolith, the rover wheels are easy to slip, sink, or even fail to move. To improve the traction performance of the rover on soft lunar soil, it is necessary to study the interaction between the wheels and the lunar soil. The deformation of the flexible wheel provides a larger contact area, which results in greater tractive force. Moreover, flexible wheels have better comfort and stability than rigid wheels, which are needed for manned rovers. However, there are few studies on the wheel soil interaction model of the heavy flexible wheel for the pressurized lunar rover. In this paper, a metal flexible wheel soil interaction model for pressurized lunar rovers was established, and the traction performance of the flexible wheel was predicted by using this model. Then, the accuracy of the wheel soil interaction model was verified by the soil bin test. The experimental results showed that the average error between the theoretical value of sinkage and the experimental value was 13.9%, and the average error between the theoretical and experimental value of drawbar pull was 11.5%, indicating that the model has high prediction accuracy. The new model can be used to predict the traction performance of flexible wheels and the experimental results can provide a reference for the flexible wheel design lunar rovers

Effect of external phosphate addition on solid-phase iron distribution and iron accumulation in Mangrove Kandelia obovata (S. L.)

In this study, a pot experiment was conducted to evaluate the effect of phosphate (PO4 3−) addition on iron (Fe) cycling in mangrove ecosystem. Kandelia obovata (S. L.), one of the dominant mangrove species in the southeast of China, was cultivated in rhizoboxes under three different levels of P concentrations. Results showed the solid-phase Fe distribution and Fe(II)/Fe(III) values in both the root zone (rhizosphere) and bulk soil (non-rhizosphere) were comparable among all P levels (p > 0.05); P addition significantly decreased the pore water Fe content both in the rhizosphere and non-rhizosphere zone (p < 0.05); higher amount of reactive Fe was found in rhizosphere sediments, while in the non-rhizosphere sediments, higher concentration of crystalline Fe was determined; P significantly increased iron plaque formation and iron accumulation in K. obovata (S. L.) tissues (p < 0.05); P addition increased K. obovata (S. L.) biomass and chlorophyll content. It was suggested that P is implicated in the Fe cycling in mangrove plants; more reactive iron, higher abundance of root Fe-reducing bacteria (FeRB) and Fe-oxidizing bacteria (FeOB), and together with higher amount of K. obovata (S. L.) root organic acids exudation result in a rapid Fe cycling in rhizosphere, which contribute to comparable solid-phase iron distribution among different P levels

Antitumor activity of curcumin is involved in down-regulation of YAP/TAZ expression in pancreatic cancer cells

Pancreatic cancer (PC) is one of the most aggressive human malignancies worldwide and is the fourth leading cause of cancer-related deaths. Curcumin (diferuloylmethane) is a polyphenol derived from the Curcuma longa plant. Certain studies have demonstrated that curcumin exerts its anti-tumor function in a variety of human cancers including PC, via targeting multiple therapeutically important cancer signaling pathways. However, the detailed molecular mechanisms are not fully understood. Two transcriptional co-activators, YAP (Yes-associated protein) and its close paralog TAZ (transcriptional coactivator with PDZ-binding motif) exert oncogenic activities in various cancers. Therefore, in this study we aimed to determine the molecular basis of curcumin-induced cell proliferation inhibition in PC cells. First, we detected the anti-tumor effects of curcumin on PC cell lines using CTG assay, Flow cytometry, clonogenic assay, wound healing assay and Transwell invasion assay. We found that curcumin significantly suppressed cell growth, weakened clonogenic potential, inhibited migration and invasion, and induced apoptosis and cell cycle arrest in PC cells. We further measured that overexpression of YAP enhanced cell proliferation and abrogated the cytotoxic effects of curcumin on PC cells. Moreover, we found that curcumin markedly down-regulated YAP and TAZ expression and subsequently suppressed Notch-1 expression. Collectively, these findings suggest that pharmacological inhibition of YAP and TAZ activity may be a promising anticancer strategy for the treatment of PC patients

Study on growth behaviour of oxide scale and its effects on tribological property of nano-TiO2 additive oil-in-water lubricant

Oil-in-water (O/W) emulsion is widely applied as a lubricant during hot rolling process. For reducing environmental impact caused by O/W emulsion, a novel nano-TiO2 additive O/W lubricant with improved stability and reduced coefficient of friction (COF) is developed. Little research, however, has been focused on the growth behaviour of oxide scale formed on the workpiece surface and its effects on the tribological property of nano-TiO2 additive O/W lubricant. In the current work, oxidation tests of high strength steel were conducted to investigate the growth behaviour of oxide scale and obtain different surface morphologies of the oxide scale. Ball-on-disk tribological tests under a temperature of 80 °C were carried out to investigate the effects of surface morphology of oxide scale on the tribological behaviour under nano-TiO2 additive O/W lubrication. The performance of the new developed lubricant was evaluated by hot rolling process. The growth mechanism of oxide scale and the modified oxide scale growth model were proposed. Tribological results indicate that oxide scale plays an important role in the tribological behaviour of nano-TiO2 additive O/W lubricant. A reduction in surface roughness can result in a decrease of COF, while the COF will increase if the surface roughness reduces too much because some of the nano-TiO2 particles cannot go through the contact area to play a positive role in lubrication

Integrated analysis of transcriptome and metabolome revealed biological basis of sows from estrus to lactation

Summary: Characterization of molecular mechanisms underlying pregnancy development of sows is important for the genetic improvement of pig breeding traits, and also provides resources for biomedical research on human pregnancy diseases. However, the transcriptome and metabolome across multiple developmental stages of sow pregnancy were still lacking. In this study, we obtained 84 distinct RNA sequencing and 42 metabolome datasets of pig blood across six development stages from estrus to lactation. We confirmed the initial sequence and exonic structural features, stage-specific molecules, expression or accumulation pattern of molecules, the regulatory mechanism of transcriptome and metabolome, and important pregnancy-related metabolites both in pigs and humans. In conclusion, we proposed the key differences among the stages of sows from estrus to lactation in RNAs and metabolites and put forward key markers. These data results were expected to provide essential resources for pig breeding and biomedical research on human pregnancy disease

Characterization of triterpenoids as possible bitter-tasting compounds in teas infected with bird's eye spot disease

Tea infected with bird's eye spot disease generally imparts a long-lasting bitter taste, which is unacceptable to most consumers. This study has comprehensively evaluated the taste profiles of infected and healthy teas and investigated their known bitter compounds previously reported in tea. Quantification analyses and calculation of dose-over-threshold (DoT) factors revealed that no obvious difference was visualized in catechins, caffeine, bitter amino acids, and flavonols and their glycosides between infected and healthy tea samples, which was also verified by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Therefore, these known bitter compounds have been ruled out as critical contributors to the long-lasting bitterness of infected teas. Furthermore, Gel permeation chromatography, sensory analysis, and UPLC-Q-TOF-MS were employed and identified 13 substances from the target bitter fractions, including caffeine, ten triterpenoids, and two oxylipins. The higher triterpenoid levels were supposed to be the reason causing the long-lasting bitterness. This study has provided a research direction for the molecular basis of the long-lasting bitterness of infected tea leaves with bird's eye spot disease