Influence of Rapeseed Cake on Iron Plaque Formation and Cd Uptake by Rice (Oryza sativa L.) Seedlings Exposed to Excess Cd.

A soil spiking experiment at two Cd levels (0.72 and 5.20 mg kg-1) was conducted to investigate the effects of rapeseed cake (RSC) at application rates of 0%, 0.75%, 1.5%, and 3.0% (w/w) on iron plaque formation and Cd uptake by rice (Oryza sativa L.) seedlings. The use of RSC did result in a sharp decrease in soil bioavailability of Cd and a significant increase in rice growth, soil pH and organic matter. Application of RSC increased the amount of iron plaque formation and this effectively inhibited the uptake and translocation of Cd into the rice seedlings. RSC was an effective organic additive for increasing rice growth and reducing Cd uptake by rice plant, simultaneously. These results could be used as a reference for the safety use of Cd polluted paddy soil.

Impacts of rapeseed dregs on Cd availability in contaminated acid soil and Cd translocation and accumulation in rice plants.

The objective of the present study was to investigate the effects of rapeseed dregs (RSD, a commonly organic fertilizer in rural China) at application rates of 0, 0.75, 1.5, and 3.0 % on Cd availability in soil and its accumulation in rice plants (Oryza sativa L., Xiangwanxian 12#, and Weiyou 46#) by means of a pot experiment. The results showed that application of RSD resulted in a sharp decrease in the soil TCLP-extractable Cd content. However, the soil TCLP-extractable Cd content in amended soil gradually increased during the rice growing period. Application of RSD significantly increased Cd transport from root to shoot and the amount of Cd accumulated in the aerial part. RSD was an effective organic additive for increasing rice grain yield, but total Cd content in rice grain was also increased. At an application rate of 1.5-3.0 % RSD, the total Cd content in Weiyou 46# brown rice was 0.27-0.31 mg kg-1, which exceeded the standard safe limit (0.2 mg kg-1) and was also higher than that of Xiangwanxian 12# (0.04-0.14 mg kg-1). Therefore, Weiyou 46# had a higher dietary risk than Xiangwanxian 12# with RSD application. We do not recommend planting Weiyou 46# and applying more than 0.75 % RSD in Cd-contaminated paddy fields.

Diversity of Arbuscular Mycorrhizal Fungi Associated with a Sb Accumulator Plant, Ramie (Boehmeria nivea), in an Active Sb Mining.

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the symbiosis of AMF associated with an antimony (Sb) accumulator plant under natural conditions. Therefore, the objective of this study was to investigate the colonization and molecular diversity of AMF associated with the Sb accumulator ramie (Boehmeria nivea) growing in Sb-contaminated soils. Four Sb mine spoils and one adjacent reference area were selected from Xikuangshan in southern China. PCR-DGGE was used to analyze the AMF community composition in ramie roots. Morphological identification was also used to analyze the species in the rhizosphere soil of ramie. Results obtained showed that mycorrhizal symbiosis was established successfully even in the most heavily polluted sites. From the unpolluted site Ref to the highest polluted site T4, the spore numbers and AMF diversity increased at first and then decreased. Colonization increased consistently with the increasing Sb concentrations in the soil. A total of 14 species were identified by morphological analysis. From the total number of species, 4 (29%) belonged to Glomus, 2 (14%) belonged to Acaulospora, 2 (14%) belonged to Funneliformis, 1 (7%) belonged to Claroideoglomus, 1 (7%) belonged to Gigaspora, 1 (7%) belonged to Paraglomus, 1 (7%) belonging to Rhizophagus, 1 (7%) belonging to Sclervocystis, and 1 (7%) belonged to Scutellospora. Some AMF sequences were present even in the most polluted site. Morphological identification and phylogenetic analysis both revealed that most species were affiliated withGlomus, suggesting that Glomus was the dominant genus in this AMF community. This study demonstrated that ramie associated with AMF may have great potential for remediation of Sb-contaminated soils.

Transforming growth factor-ß1-induced epithelial-mesenchymal transition in human esophageal squamous cell carcinoma via the PTEN/PI3K signaling pathway.

Epithelial-mesenchymal transition (EMT) is a crucial step for the invasive and metastatic properties of malignant tumor cells during tumor progression. Numerous signaling pathways are involved in the process of EMT in cancer, such as the EMT-inducing signal transforming growth factor (TGF)-ß and the recently demonstrated PTEN/PI3K signaling pathway. To date, no data have been reported concerning the influence of PTEN/PI3K signaling pathway on EMT in human esophageal squamous cell carcinoma (ESCC) and how TGF-ß1 and PTEN/PI3K act through multiple interconnected signaling pathways to trigger events associated with EMT and tumor progression. Our data showed that the PTEN/PI3K pathway was active in human ESCC tissues in vivo, particularly in ESCC with decreased E-cadherin and increased vimentin protein expression, poor differentiation, deep invasion and lymph node metastasis, which are responsible for EMT and tumor progression. In addition, in the human ESCC cell line (EC-1) in vitro, TGF-ß1 treatment markedly induced EMT, including morphological alterations, a decrease of E-cadherin and an increase of vimentin levels and enhanced mobility and invasiveness. Furthermore, the PTEN/PI3K pathway was also activated in the process of TGF-ß1-induced EMT in EC-1 cells in vitro, whereas inhibition of the PTEN/PI3K pathway by using pcDNA3.1 PTEN partially blocked TGF-ß1-induced EMT and reduced mobility and invasiveness. These studies suggest that TGF-ß1 and the PTEN/PI3K signaling pathway contribute to EMT and the PTEN/PI3K signaling pathway is a key regulator of TGF-ß1­induced EMT in ESCC. Disruption of the PTEN/PI3K pathway involved in TGF-ß1-induced EMT may provide possible routes for therapeutic intervention to ESCC.

[Influence of the river-lake relation change on the distribution of heavy metal and ecological risk assessment in the surface sediment of Poyang Lake].

Effects of river (Yangtze River)-lake (Poyang Lake) relation on the distribution and potential ecological risk of Cu, Pb, Zn, Cr and Cd were investigated in surface sediment of Poyang Lake under different waterregimens. The results indicated: (1) the sediments of Poyang Lake were polluted by various concentrations of heavy metals mainly originated from particulates of Yangtze River, and Cu and Pb were the main pollution factors. The pollution level of determined heavy metals followed the order of Cu > Pb > Zn > Cr >Cd. The concentration ranges of Cu, Pb, Zn, Cr and Cd in the sediment of Poyang Lake were 13.1-108.1 mg.kg-1 , 37-119.1 mg.kg-1, 29.9-129.9 mgkg-1, 13.3-98.6 mgkg-1 and 0. 19-2.77 mg.kg-1 during the wet period, and 3.05-69.7 mg.kg-1, 27.5-105 mgkg-1, 18.8-95.4 mg.kg-1, 7.34-70 mg.kg- and 0.033-0.406 mg.kg-1 during the dry period respectively. The region with the highest heavy metal concentrations was located in water input area of the " Five River" and water output area of " Hukou" ; (2)The regions with high risk of heavy metals in sediment were mainly located in the area of the trail of "Five Rivers" during the wet period; while during the dry period, the area with high risk of heavy metals in sediment enlarged, which was not only limited in the area of the trail of "Five Rivers", but also enlarged northwards. The potential ecological risk of "Hukou" was relatively high, however, the potential ecological risk of the sediment in the whole lake during the dry period was lower than that during the wet period. (3) With the change of river-lake relation, water level rose, the maintaining time was shortened during the wet period, the dry season appeared ahead of schedule, the transformation course of Poyang Lake from "Lake morphology" to " River morphology" increased, and the typical river properties were enhanced, which resulted in the decreased potential ecological risk of heavy metals in sediment of the whole lake, however, the area of high risk-region was enlarged northwards.

[Effects of thiourea on pH and availability of metal ions in acid red soil].

Through the simulation research, the effects of application of thiourea and urea on pH and availability of metal ions in acid red soil were studied, and the results showed that after applying urea, the soil pH increased in the first experimental stage and then reduced gradually to a low level, however, decreased trends of soil pH values were inhibited by the application of thiourea, especially when the concentration of thiourea reached to 5.0 mmol x kg(-1) dry soil, the soil pH was stable at high level, which exceeded to 6.0. It proved that the application of thiourea could inhibit the soil acidification due to urea application. After applying urea with different concentrations of thiourea, the available contents of Zn and Al decreased with the increasing concentration of thiourea, nevertheless, when the concentration of thiourea reached to 5.0 mmol x kg(-1), the available content of Mn was stable at high level which was over 110 mg x kg(-1). In addition, the results showed a highly significant negative correlation between the soil pH and the available content of Cu, Zn and Al, but for Mn, no discipline was found between the soil pH and the availability after applying thiourea. Moreover, the soil pH became higher after applying urea with thiourea compared to add urea only, which led to the decreasing of available content of Al, and it was benefited for the control of the phytotoxic effect of Al. The available content of Mn in the soil not only depended on soil pH but also the content of thiourea due to its redox and complexing reaction with Mn.

Relationship between TWIST expression and epithelial-mesenchymal transition of oesophageal squamous cell carcinoma.

We have investigated mRNA and protein expression of TWIST, Vimentin and E-cadherin in ESCC (oesophageal squamous cell carcinoma) and explored their relationship with tumour's infiltration and metastasis. RT-PCR (reverse transcriptase-PCR) was used to evaluate mRNA expression of TWIST, E-cadherin and Vimentin in 40 cases of ESCC. The protein expression of the genes was examined by immunohistochemical staining in each specimen. Expression of TWIST, E-cadherin and Vimentin mRNA and protein with clinicopathologic parameters were analysed. mRNAs of TWIST, Vimentin and E-cadherin were expressed in 75, 55 and 35% respectively of ESCC, i.e. significantly different from that in normal oesophageal mucosa (15, 0 and 85% respectively; P<0.01). In ESCC with LN (lymph node) metastasis, expression of TWIST and Vimentin mRNA, but not E-cadherin mRNA was significantly higher (100 and 83%) than in ESCC without LN metastasis (64 and 43%, P=0.018) respectively. Levels of mRNA expression of the 3 genes followed similar patterns to their above-mentioned frequencies. Protein expression of TWIST, E-cadherin and Vimentin were observed in 70, 35 and 50% respectively of ESCC, which were significantly different from normal mucosa (15, 80 and 0%; P<0.001). In ESCC with LN metastasis, protein expression of TWIST and Vimentin, but not E-cadherin, were significantly higher (100 and 75%) than in ESCC without LN metastasis (61 and 39%). Protein expression of TWIST was positively correlated with Vimentin (r=0.327, P=0.039), but negatively correlated with E-cadherin (r= -0.633, P=0.000). Thus, both mRNAs and proteins of TWIST and Vimentin were significantly overexpressed in ESCC, especially ESCC with LN metastasis. The mRNA and protein of E-cadherin were down-regulated in ESCC. These results suggest potential roles of TWIST as the promoter of tumour invasion and metastasis associated with down-regulation of E-cadherin.

[Buoyancy regulation and vertical distribution of Planktothrix mougeotii in the simulator experiments].

The dominance of gas-vacuolated cyanobacteria is often attributed to their buoyancy and buoyancy in response to environmental conditions. Lake simulator experiments (4 m high and 1 m diameter) and pyrex bottle experiments (10 L) were applied to investigate the buoyancy regulation and vertical distribution of Planktothrix mougeotii in eutrophic lakes at 28 degrees C. During light phase, the filaments stratify in the 2-3 m after 8 h light exposure and the biomass at the layer attach maximum after 12 h light exposure. During dark phase, the filaments are tent to migrate to the surface. 20% of filaments migrate to the surface after 12 h and 50% of filaments migrate to the surface after 48 h. The buoyancy regulation under light condition is that filaments stratify in 10 micromol x (m2 x s)(-1) layers, and the filaments above the layer sink down, while those suspended below the layer float up. The amplitude of diel changes in buoyancy is related to photon irradiance, and the change of buoyancy in light [100 micromol x (m2 x s)(-1)]/ dark is higher than its in light [25 micromol x (m2 x s)(-1)]/ dark. Carbohydrate ballasting may be the only mechanism for buoyancy changes in Planktothrix mougeotii filaments during the period.

[Effects of surfactants on adsorption of methyl parathion by neutral alumina].

The sorption of methyl parathion by neutral alumina which was modified by ionic surfactants such as SDS, SDBS and CTMAB was studied. It showed that the adsorbability of alumina to methyl parathion were related to the type and concentration of surfactant and pH of the system. The adsorbabilities of alumina on three kinds of surfactants were different. When pH = 7, the adsorbance of SDS was the largest, but the adsorbance of CTMAB was the smallest. When pH = 4, the adsorbance of SDS or SDBS was increased, while the adsorbance of CTMAB was decreased. The adsorbability of alumina was strengthened, not weakened, by the cooperation of pollutant and anionic surfactant, while the sorption of methyl parathion by alumina with cationic surfactant was weakened. These features had the practical value when neutral alumina is used to remove more than one contaminants from wastewater.

[Critical collapse pressure of gas vesicles in six strains of cyanobacteria].

Two methods including filtration (vacuity is 0.02 MPa) and centrifugation ( < 500 r/min) were applied to concentrate algal biomass, and capillary compression tube and the concentrated algae suspensions, critical pressure distribution of gas vesicles in six cyanobacteria were also investigated. The results showed that unicellular Microcystis aeruginosa cells couldn't be concentrated effectively by filtration or centrifugation, but colony of Microcystis wesenbergii and Microcystis flosaquae, and filament of Planktothrix mougeotii could be concentrated by centrifugation and filtration respectively. Both filtration and centrifugation had a negligibly impact on gas vesicles content of cells, and the loss of gas vesicles was lower than 7%. The mean critical pressure values of five strains Microcystis were very close, which ranged from 0.64 to 0.67 MPa, and the mean critical pressure of P. mougeotii was 0.715 MPa. All of the six cyanobacteria were isolated from three shallow lakes, and their mean critical pressure values were lower than those cyanobacteria that inhabit in deep lakes or reservoirs. At the same condition of illumination density and temperature, turgor pressures of two unicellular Microcystis were higher than those of colonial Microcystis.

[Effects of EDTA and iron on growth and competition of Microcystis aeruginosa and Scenedesmus quadricauda].

Not only population density of phytoplankton but also its community structure were influenced by iron limitation. The growth and competition of a cyanobacterium Microcystis aeruginosa and a green alga Scenedesmus quadricauda at different iron and EDTA concentrations were investigated using batch cultures. The results showed that the growth of M. aeruginosa was significantly inhibited whereas S. quadricauda wasn't when EDTA at high concentrations (> or = 13.5 micromol/L), and consequently, it favored the dominance of S. quadricauda. Moreover, increasing iron concentration from 3 micromol/L to 18 micromol/L could greatly alleviate the growth inhibition of M. aeruginosa while increasing concentration of other microelements e.g. B, Mn, Zn, Cu, Mo didn't. These results suggest that high EDTA concentration decreases iron availability for M. aeruginosa, but not for S. quadricauda. The reason that the two algae respond to high EDTA concentrations differently is that their adsorption strategies for iron should be different.

Solubilization and desorption of methyl-parathion from porous media: a comparison of hydroxypropyl-beta-cyclodextrin and two nonionic surfactants.

The removal of hydrophobic organic compounds (HOCs) from soils and sediments by water flushing is often constrained by sorption interactions. The development of improved methods for remediation of contaminated soils has emerged as a significant environmental priority. Increasing HOCs desorption and mobility in soil using surfactants is considered to be one of the most suitable on-site techniques for soil remediation. A major concern regarding the use of surfactants for environmental restoration is the potential loss to the environment of large amounts of surfactant through sorption of nonionic types. A study was conducted to investigate whether surfactants and cyclodextrins can be used to enhance the transport of methyl-parathion in a contaminated soil. At aqueous concentrations of surfactants tested, the proportion of each surfactant sorbed to the soil increased with increasing surfactant concentrations. The maximal adsorbed mass is about 5,130 and 14,200 microg/g for Brij 35 and Tween 80, respectively. In the case of nonionic surfactants, sorption attenuates surfactant effectiveness by increasing the organic carbon content of the soil matrix and retarding transport of methyl-parathion through batch and soil column experiments. However, in contrast with the surfactants, hydroxypropyl-beta-cyclodextrin (HPCD) does not interact with the soil tested. The nonreactive nature of cyclodextrins, combined with its large affinity for HOCs suggests that it should have an advantage versus adsorbing surfactants for decreasing HOC distribution coefficients in subsurface systems.

Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L).

Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L) were studied in a pot experiment by measurement of fresh weights of the plants, determination of surperoxide dismutase (SOD), peroxidase (POD), and lipid peroxidation (MDA) in the plant organs, and observation of injury symptoms. The experimental results demonstrated that all treatments of Cd2+, Zn2+, and/or acid rain significantly decreased fresh weights of kidney bean and caused toxic effects on growth of the plants, especially higher amounts of Cd2+ and Zn2+ and higher acidity of acid rain. Combination of these three pollutant factors resulted in more serious toxic effects than any single pollutant and than combinations of any two pollutants. SOD, POD, and MDA in the plant organs changed with different pollution levels, but MDA content in the leaves showed the best relationship between the pollution levels and toxic effects.