[Effect of cadmium stress on root vigor and accumulation of elements Ca, Mg, Mn, Zn, Fe in Salix variegate.] / é•‰èƒè¿«å¯¹ç§‹åŽæŸ³æ ¹ç³»æ´»åŠ›åŠå ¶Ca、Mg、Mn、Zn、Fe积累的影响.

In order to explore the effect of cadmium stress on root vigor and accumulation of five kinds of conventional metal elements in Salix variegata, a hydroponic experiment with different cadmium treatments were conducted. The cadmium treatments included 0 mg·L-1 (CK), 2 mg·L-1 (T1), 10 mg·L-1 (T2), 20 mg·L-1 (T3) and 50 mg·L-1 (T4). The root vigor and distribution of cadmium and five kinds of conventional metal elements (including Ca, Mg, Mn, Zn and Fe) in S. variegata were tested. The results showed that: 1) The root vigor of S. variegata decreased with increasing cadmium stress gradually. Compared to control, the root vigor decreased significantly in treatments with the cadmium concentration reaching and exceeding 10 mg·L-1. 2) With increasing the cadmium concentration, the abilities of S. variegata to absorb and accumulate Fe in leaves were inhibited significantly; the abilities to absorb and accumulate Mg, Mn and Fe in phloem were inhi-bited significantly; the abilities to absorb and accumulate Ca, Mg, Mn, Zn and Fe in xylem had no significant differences; and the abilities to absorb and accumulate Ca, Mg, Mn, Zn and Fe in root were inhibited significantly. It could be concluded that cadmium had antagonistic effect on the accumulation of the other metal elements, especially Zn in plant root. 3) With increasing concentrations of cadmium, the translocation factors of Ca, Mg, Mn and Zn increased significantly when compared to control, while there was no significant influence on Fe. 4) Under cadmium stress, there was a significantly negative correlation between the accumulations of cadmium and Ca in S. variegate root, and a very significantly negative correlation between the accumulations of cadmium and the other four kinds of conventional metal elements, indicating that the change of conventional metal elements in S. variegate root could be one of the indices of the degree of cadmium stress.

[Value of dual-time-point (18)F-fluorodeoxyglucose integrated positron emission and computed tomography in differentiation of malignant from benign gastrointestinal diseases].

OBJECTIVE: To explore the value of dual-time-point (18)F-fluorodeoxyglucose integrated positron emission and computed tomography ((18)F-FDG PET-CT) in differentiation of malignant from benign gastrointestinal diseases. METHODS: Sixty five patients with suspected gastrointestinal lesions underwent dual-time-point (18)F-FDG PET-CT imaging. Standardized uptake value (SUV) was calculated for semi-quantitative assessment. The SUV of the two acquisitions were signed SUV(early) and SUV(delayed), respectively. Then the change of SUVmax (ΔSUVmax) was calculated. The ROC curves of the SUV(early), SUV(delayed) and ΔSUV were drawn to find the best cut-off point value for differential diagnosis, and then the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated, respectively. RESULTS: Of the malignant lesions, the SUVmax in delayed imaging were significantly higher than those in early imaging, while there were no significant differences of SUVmax between the two images of the benign lesions. The ΔSUVmax of the malignant lesions were significantly higher than that of the benign ones. Taking the SUVmax higher than 9.2 in early imaging as positive diagnostic criteria, the sensitivity was 72.7%, the specificity was 85.7%, the positive predictive value was 91.4%, the negative predictive value was 60.0%, and the accuracy was 76.9%. Taking the SUVmax higher than 10.9 in delayed imaging as positive diagnostic criteria, the sensitivity was 75.0%, the specificity was 90.5%, the positive predictive value was 94.3%, the negative predictive value was 63.3%, and the accuracy was 80.0%. Taking the ΔSUVmax higher than 5.1% as positive diagnostic criteria, the sensitivity was 95.5%, the specificity was 85.7%, the positive predictive value was 93.3%, the negative predictive value was 90.0%, and the accuracy was 92.3%. The accuracy of dual-time-point (18)F-FDG PET-CT imaging was significantly higher than that of single-time point (18)F-FDG PET-CT imaging. CONCLUSION: Dual-time-point (18)F-FDG PET-CT imaging is a useful method for differentiating malignant from benign gastrointestinal diseases, and it is superior to the single-time point (18)F-FDG PET-CT imaging.

Curcumin inhibits hERG potassium channels in vitro.

Curcumin is reported to exert antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anti-tumor activities. The human ether-a-go-go related gene (hERG) encodes the rapid component of the delayed rectifier K⁺ currents. Inhibition of hERG K⁺ channels leads to cardiac repolarization prolongation, which contributes to either the anti-arrhythmic effects of anti-arrhythmic drugs, or the pro-arrhythmic effects (induction of long QT syndrome) of some drugs not used for anti-arrhythmias. Since curcumin shows multiple beneficial effects and clinical significance, the aim of the present study is to investigate the effect of curcumin on hERG K⁺ channels, elucidating its potential cardiac therapeutic or toxic effects. In whole-cell patch-clamp experiments, we found that curcumin inhibited hERG K⁺ currents in HEK293 cells stably expressing hERG channels in a dose-dependent manner, with IC50 value of 5.55 µM. The deactivation, inactivation and the recovery time from inactivation of hERG channels were significantly changed by acute treatment of 10 µM curcumin. Incubation of 20 µM curcumin for 24h reduced the HEK293 cell viability. Intravenous injection of maximal amount of curcumin in rabbits (20 mg/animal) did not affect the cardiac repolarization manifested with QTc value. We conclude that curcumin inhibits hERG K⁺ channels in vitro.

Tetraethylammonium enhances the rectal and colonic motility in rats and human in vitro.

Hirschsprung's disease is the congenital absence of generating the peristaltic contractions transmitting from the proximal colon to rectum. We previously have found that tetraethylammonium (TEA), the nonselective Ca(2+)-activated K(+) channel blocker, increases the maximal contractile force and the amplitude of the contraction in rat duodenum. The present study is to test the effect of TEA on motility of colon and rectum from rats and Hirschsprung's disease patients in vitro, in order to find an alternative method to improve the syndrome of Hirschsprung's disease. The rectal and colonic motility was recorded by a tension transducer connected to a biology function experiment system. Histology was analyzed with standard hematoxylin and eosin staining. TEA (1, 3, and 5 mM) significantly increased the amplitude and frequency of contractility of colon and rectum from rats in longitudinal and circular direction. TEA at 5 and 15 mM concentrations showed no effect on histology of colon and rectum from rats that were administered locally with TEA into colon lumen from anus for 10 days. TEA at 15 mM increased the amplitude and frequency of contractions of the colon and rectum from Hirschsprung's disease patients. Our data showed that TEA increased the contractility of colon and rectum from rats and Hirschsprung's disease patients in vitro, suggesting that local administration of TEA in colon or rectum lumen might be an alternative method to ameliorate the syndrome of Hirschsprung's disease patients who are not cured completely by surgery or not suitable for surgery.

The structure and origin of dissolved organic matter studied by UV-vis spectroscopy and fluorescence spectroscopy in lake in arid and semi-arid region.

To develop a proper indicator which could predict water quality and trace pollution sources is critically important for the management of sustainable aquatic ecosystem. In our study, seven water samples collected from Wuliangsuhai Lake in Inner Mongolia were used. UV-visible spectra and synchronous fluorescence spectra were applied to investigate the humification degree and aromatic structure of dissolved organic matter (DOM) extracted from water samples. The results showed that both samples from W1 site and W3 site display lower humification degree and less aromatic structure, where industrial wastewater and domestic sewage, and reclaimed water of farmland irrigation, were accepted respectively. After computing the values of SUVA(254), A(280), A(250/365), A(253/203) and A(226-400), we reached the conclusion that they have a consistent trend (W4> W6> W5> W2> W7> W1> W3). Fluorescence index (f(450/500)) was always utilised to interpret the origin of organic matter in a complex aquatic environment system. Values of f(450/500) are closer to 1.60, indicating that humic substances derived from terrestrial sources and biological sources. Our study demonstrated that reclaimed water of farmland irrigation, industrial wastewater and domestic sewage will definitely influence the humification degree and amount of the aromatic structure of DOM.

[Study on solid surface fluorescence characteristic of saline soils around lakes in arid and semiarid regions].

Fluorescence spectroscopy relies on the fluorescence emitted by rigid conjugated systems and thus has been increasingly used to assess the soil organic matter (SOM) humification. This technique is widely applied to solution samples of humic substances, and so far no information exists about its applicability to solid-phase soil samples. Composite soil samples of different depths (0-20, 20-40 and 40-60 cm) were collected from four different halophyte communities along a saline-impact gradient, namely, Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA) located around Wuliangsuhai Lake. A humification index based on solid surface fluorescence spectroscopy (HIX(SSF)) was proposed, and compared with conventional humification indices I400/I360, I470/I360, I465/I399 and A4 /Al. There were close positive linear correlations between HIXass and 1400/1360, 145/I399 and A4/A1, but a poor positive linear correlation existed between the HIX(SSF) and I470/I360. The results indicated that HIX(SSF) can be taken as a tool to assess the soil humi fication. The HIX(SSF) of the CSE and CSG varied inappreciably within soil profiles and there was no trend with depth. However the HIX(SSF) varied appreciably in the CKF and CSA, and the HIX(SSF) of the bottom soil profile was higher than that of the other profiles. As a whole, the soil humification degree was low around Wuliangsuhai Lake, and the ecological environment was relatively fragile. The salinity showed a strong negative linear relationship with the I400/I360, I470/I360, I465/I399 and A4/A1, but a good negative linear relationship with the HIX(SSF). The results indicated that the degree of the SOM humification increased with the drop in the salinity. The HIX(SSF) can be an indicator not only of the degree of SOM humification, but also of the process of the salinisation.

[Extraction, selenium-nanoparticle preparation and anti-virus bioactivity determination of polysaccharides from Caulerpa taxifolia].

OBJECTIVE: To extract polysaccharides from Caulerpa taxifolia and determine its anti-virus bioactivity. METHODS: The crude polysaccharides were extracted by hot water and precipitated with ethanol, then they were further purified by DEAE-Cellulose and Sephadex G-200 chromatography. After determined by chemicophysical analysis, the polished polysaccharides were selenium treated and bio-assayed by MT and CPE methods. RESULTS: The crude extraction from Caulerpa taxifolia was a kind of sulfated polysaccharides in which the average content of polysaccharides and sulfate were 27. 9% and 11.5%, respectively. The recovery rate of the polished polysaccharides was 66.3% after the 2-column purification. The IC50 and TI of the purified polysaccharide SCpl1 were 2.2 mg/mL and 3057.0, respectively. After treated with selenium, the average diameter of the nanoparticle was 28.6 nm, and its bioactivity and TI index were enhanced significantly although with a higher cytotoxicity. CONCLUSION: The polysaccharides from Caulerpa taxifolia and its selenium particles was a kind of bioactive substance for anti-virus drug-candidate development.