[Blocking Effects of Foliar Conditioners on Cadmium, Arsenic, and Lead Accumulation in Wheat Grain in Compound-contaminated Farmland].

Heavy metal contamination of soil has become a hot issue of social concern due to its impact on the safety of agricultural products in recent years. Wheat is one of the most dominant staple food crops worldwide and has become a major source of toxic metals in human diets. Foliar application was considered to be a more efficient and economical method of heavy metal remediation. Field experiments were carried out in Cd-, As-, and Pb-contaminated farmland soils. The effects of foliar conditioners on the accumulation of Cd, As, and Pb in wheat grains were investigated after being sprayed with Zn (0.2% ZnSO4), Mg (0.4% MgSO4), and Mn (0.2% MnSO4) separately and in combination. Thus, the effective foliar conditioners were selected to block the accumulation of Cd, As, and Pb in wheat grains grown in combined heavy metal-contaminated farmland in north China. The results showed that, compared with that in the control, the Cd, As, and Pb contents in wheat grains of the Zn+Mg+Mn foliar treatment were significantly decreased by 18.96%, 23.87%, and 51.31%, respectively, and TFgrain/straw decreased by 14.62%, 27.73%, and 47.70%, respectively. Thus, spraying the compound foliar conditioner of Zn+Mg+Mn could effectively reduce heavy metal accumulation in wheat grains through inhibition translocation of those metals from stem leaves to grain. In addition, the results indicated that Cd and As were mainly distributed at the central endosperm (34.08%-37.08%), whereas Pb was primarily distributed at the pericarp and seed coat (27.78%) of the wheat grain. Compared with that in the control, spraying the compound foliar conditioner of Zn+Mg+Mn extremely decreased Cd and As accumulation in the aleurone layer of the wheat grain by 81.10% and 82.24%, respectively. Except for the pericarp, seed coat, and central endosperm layers, the Pb content in each grain layer was dramatically decreased by 42.85% to 91.15%. There was only a significant negative correlation between heavy metal content and Zn content in the aleurone layer (P2) of wheat flour. In summary, the accumulation of Cd, As, and Pb in wheat grains, especially in the aleurone layer, could be effectively reduced by foliar conditioner application at the jointing, booting, and early filling stages of wheat, separately. Furthermore, besides the foliar treatment, removing wheat bran to reduce Cd contamination in wheat grains is highly recommended to ensure the safe production of wheat.

[Distribution and Transport of Cadmium and Arsenic in Different Aboveground Parts of Wheat After Flowering].

To investigate the effects of leaves and stems on the accumulation and transport of cadmium(Cd) and arsenic(As) in wheat shoots after flowering, a field experiment was conducted in a typical Cd and As co-contaminated agricultural land to explore the distribution and translocation of Cd and As in the different parts of two wheat cultivars after flowering. The results showed that Cd was mainly distributed in the nodes of two varieties, and the translocation factors of Cd from internode 3 to node 2, from internode 2 to node 1, and from sheath 1 to node 1 were markedly higher than those of other aboveground parts during the grain-filling stage. However, Cd was mainly distributed in the leaves, and the translocation factors of Cd from sheath to leaf and from node 1 to rachis was significantly higher than those of other parts at the mature stage. In addition, the transport capacity of Cd from glume to rachis and from rachis to grain in JM22 was significantly lower than that in SN28, which significantly reduced Cd concentrations in the rachis, glume, and grain of JM22 by 22.3%, 40.8%, and 44.4%, respectively. Meanwhile, As was mainly distributed in the wheat leaves from the grain-filling stage to the mature stage, and As concentrations in the glume and grain of JM22 were 25.8% and 33.3% lower than those of SN28, respectively. Additionally, the translocation factors of As from the sheath to the node were significantly 438% and 190% higher than that from leaf to sheath and from node to internode during the whole grain filling stage and mature stage. Moreover, the translocation factors of As from glumes to grains and from rachis to grains in JM22 were 40.6% and 44.4% lower than that in SN28, respectively. In summary, flag leaf, node 1, and the rachis had regulated Cd transport and accumulation in wheat grains, whereas leaf 3, flag leaf, node 1, the glumes, and the rachis were mainly responsible for As transport and accumulation in wheat grains.

[Characteristics and Health Risk Assessment of Cadmium, Lead, and Arsenic Accumulation in Leafy Vegetables Planted in a Greenhouse].

In recent years, dust pollution has occurred frequently in spring and haze or fog in autumn and winter. The inhalable particulate matters in the atmosphere, especially PM2.5, loaded in heavy metals such as cadmium, lead, and arsenic, are easily taken up by leafy vegetables and accumulate in the edible parts. It is not clear whether the accumulation of heavy metals in the edible parts of leafy vegetables in greenhouses is also affected by atmospheric deposition. Therefore, a field experiment was conducted to explore characteristics and health risk assessment of cadmium, lead, and arsenic accumulation in leafy vegetables planted in a greenhouse using six types of common leafy vegetables (spinach, leaf lettuce, lettuce, pakchoi, Chrysanthemum coronarium, and fennel) in the Beijing-Tianjin-Hebei region. The results showed that C. coronarium, pakchoi, and spinach are the leafy vegetables with a low accumulation of Cd, Pb, and As, respectively. Fennel is the leafy vegetable with a low accumulation of Cd and Pb. In the greenhouse, Pb concentrations in PM2.5 were 42.6 and 8.4 times of Cd and As, respectively. Moreover, PM2.5-Pb contributed on average 36.5% to the edible parts of six kinds of leafy vegetables, which indicated that the Cd, Pb, and As accumulated in leafy vegetables were mainly derived from the soil. Meanwhile, the concentrations of Cd, Pb, and As in the edible parts of vegetables did not exceed the safety limitations of three heavy metals (GB 2762-2017), and Pb accumulation in leafy vegetables does not pose a health risk to humans. However, Cd in the leafy vegetables could threaten the health of adults and children, except for the intake of fennel. Conversely, As in the C. coronarium could threaten the health of adults and children.

Bioimaging of Pb by LA-ICP-MS and Pb isotopic compositions reveal distributions and origins of Pb in wheat grain.

Atmospheric heavy metal deposition in agroecosystems has increased recently, especially in northern China, which poses serious risks to crop safety and human health via food chain. Wheat grains can accumulate high levels of Pb even when wheat is planted in soils with low levels of Pb. However, the influence of atmospheric deposition on the accumulation and distribution of Pb in wheat grain is still unclear. A field survey was conducted in three districts (A: a district with industrial and traffic pollution; B: a district with traffic pollution; and C: an unpolluted district) in Hebei Province, North China. The grain of wheat cultivated in district A accumulated more Pb from soil and atmospheric deposition than those in other districts, and the bran from district A contained 3.50 and 2.04 times more Pb than those from districts B and C, respectively. The Pb distribution pattern in wheat grain detected by laser ablation inductively coupled mass spectrometry (LA-ICP-MS) was characterized by accumulation mostly in the pericarp and seed coat rather than in the crease, embryo and endosperm. Furthermore, Pb isotopic data showed that airborne Pb was the major source (>50%) of Pb in wheat grain. Interestingly, average contributions of Pb from atmospheric deposition to white flour (78.22%) were higher than its contributions to bran (56.27%). In addition, wheat flag leaves were exposed to PbSO4 at the booting stage, and much greater Pb accumulation (0.33-0.48 mg/kg) was observed in exposed wheat grain than in the control (P < 0.05), PbSO4 constituted most (82.80-100%) of the Pb in the wheat grain. In summary, the results confirmed the efficient foliar Pb uptake and transfer from atmospheric deposition into wheat grain. It would be a new sight for understanding the contribution of airborne Pb to Pb accumulation in wheat grains.

[Uptake and Accumulation of Cadmium and Zinc by Two Energy Grasses: A Field Experiment].

The remediation potential of large biomass energy grasses in cadmium-contaminated soil remains ambiguous. A field experiment was carried out in a cadmium-contaminated farmland using two energy grasses and two control plants. The two energy grasses were hybrid pennisetum (Pennisetum americanum×P. purpureum, PAP) and purple elephant grass (P. purpureum 'Purple', PPP), and the two control plants were Iris lactea var. chinensis (ILC) and a cadmium hyperaccumulator, Noccaea caerulescens (NC). The results showed that the aboveground biomass of PAP was the largest among the four plants, and 126 and 36 times that of NC and ILC, respectively, but no significant difference with that of PPP. The concentrations of cadmium and zinc in the shoots and roots of NC were significantly higher than in the other plants. Zinc concentrations in the shoots and roots of ILC were lower than in the other plants, while cadmium concentrations were significantly higher than in PAP and PPP (P<0.05). The amounts of cadmium and zinc accumulated in the shoots of PPP were the highest among the four plants, while cadmium concentrations in the shoots and roots of PPP were significantly lower than in ILC and NC (P<0.05). Cadmium amounts accumulated in PPP shoots were 7.0 and 4.1 times that of ILC and NC, respectively. Zinc amounts accumulated in PPP shoots were 41 and 11 times that of ILC and NC, respectively (P<0.05). Cadmium accumulation in the shoots of PAP was 19.4% lower than in PPP, and zinc accumulation had no significant difference with that of PPP. NC, having a bioconcentration factor of shoot (BCFS) and a translocation factor (TF) for cadmium and zinc both larger than 1, is usable for phytoextraction of soils contaminated by cadmium and zinc. ILC, having a bioconcentration factor of root (BCFR) larger than 1 and a TF lower than 1 for cadmium, is usable for the phytostabilization of soils contaminated by cadmium. PPP, having a BCFR larger than 1 and a TF lower than 1 for zinc, can be used in the phytostabilization of soils contaminated by zinc. Under field conditions, PPP and PAP showed great potential for the extraction and removal of cadmium and zinc from soil due to their large biomass and ability to produce economic benefits, have good application prospects.

[Characteristics of Cd, As, and Pb in Soil and Wheat Grains and Health Risk Assessment of Grain-Cd/As/Pb on the Field Scale].

In recent years, heavy metal pollution in farmlands has become increasingly serious because of human activities such as metal smelting, sewage irrigation, and road traffic in China. A field survey was conducted to investigate characteristics of Cd, As, and Pb in soil and wheat grains and assess the health risk of grain-Cd/As/Pb to humans on the fields scale. The farmland was influenced by smelter and sewage irrigation in the attitude and by road traffic in the horizon. The results showed that in farmland soil with moderate pollution levels, Cd, As, and Pb concentrations in soil samples all exceeded the risk screening values of farmland soil (GB 15618-2018), and the exceeding rates were 100%, 100%, and 36.7% respectively; the exceeding rates of Cd and Pb concentrations in wheat grains were 76.7% and 13.3%, respectively (GB 2762-2017). Distance from smelter, river of sewage irrigation, and road had no significant effect on Cd, As, and Pb concentrations in soil but had a significant effect on Cd and As concentrations in wheat grains, with the median Cd and As concentrations of the closest group being 14.9% and 41.8%, respectively, higher than the highest group (P<0.05). The Pb concentrations in soil and wheat grains were influenced by road traffic; the median Pb concentrations of the closest group were 78.9% and 471%, respectively, higher than the highest group (P<0.05). Cd and As in wheat grains have carcinogenic risks (Ri>1×10-4), RCd > RAs, Rchildren > Radult, while Pb poses no health risks in this farmland.

The role of Melatonin receptor MTNR1A in the action of Melatonin on bovine granulosa cells.

Granulosa cells (GCs) play an important role in ovarian follicle growth, development, and follicular atresia. In the present study, we investigated the effects of Melatonin on bovine GCs, and asked if MTNR1A was involved in their response to this indole hormone. Our results indicated that Melatonin inhibited GC apoptosis by up-regulating the expression of BCL2, BCL-XL, GPX4, and SOD1, and down-regulating the expression of BAX, CASP3, and TP53. Moreover, Melatonin modulated bovine GC function by decreasing the expression of INHA, INHBB, FSHR, and TGFBR3, and the abundance of Inhibin ß and Activin B, while increasing the expression of LHR, INHBA, and secretion of progesterone by GCs. In contrast, knockdown of MTNR1A significantly increased the expression of BAX, CASP3, TP53, INHA, FSHR, and TGFBR3, as well as Inhibin ß abundance, while decreasing the expression of BCL2, GPX4, SOD1, and LHR, and production of progesterone and estradiol; no effect was observed on the expression of BCL-XL, INHBA, or INHBB. These results suggest that Melatonin and MTNR1A play an important role in modulating bovine GC function by regulating cellular progression, apoptosis, hormones secretion, and reproduction-related genes. Furthermore, altered expression of MTNR1A could affect how bovine GCs respond to Melatonin.

[Intracorporeal Roux-en-Y reconstruction after laparoscopic distal gastrectomy: a report of 20 cases].

OBJECTIVE: To investigate the safety and feasibility of intracorporeal Roux-en-Y reconstruction after laparoscopic distal gastrectomy. METHODS: Clinical data of 20 patients undergoing laparoscopic distal gastrectomy and intracorporeal Roux-en-Y reconstruction in our hospital from August 2012 to March 2013 were analyzed retrospectively. RESULTS: Totally laparoscopic distal gastrectomy was successfully performed in all the patients. The mean operation time was (190.8±53.6) min, the mean operative blood loss was(122.4±57.7) ml, and mean number of harvested lymph node was 31.2±5.7. Tumor-free proximal margin was confirmed by pathological examination in all the patients. The mean time to first flatus and hospital stay were (2.6±1.6) d and (8.1±2.0) d. One case developed pulmonary infection postoperatively, but no anastomosis related complication was observed. CONCLUSION: Intracorporeal Roux-en-Y reconstruction after laparoscopic distal gastrectomy is safe and feasible.

Methylated arsenic species in plants originate from soil microorganisms.

• Inorganic arsenic (iAs) is a ubiquitous human carcinogen, and rice (Oryza sativa) is the main contributor to iAs in the diet. Methylated pentavalent As species are less toxic and are routinely found in plants; however, it is currently unknown whether plants are able to methylate As. • Rice, tomato (Solanum lycopersicum) and red clover (Trifolium pratense) were exposed to iAs, monomethylarsonic acid (MMA(V)), or dimethylarsinic acid (DMA(V)), under axenic conditions. Rice seedlings were also grown in two soils under nonsterile flooded conditions, and rice plants exposed to arsenite or DMA(V) were grown to maturity in nonsterile hydroponic culture. Arsenic speciation in samples was determined by HPLC-ICP-MS. • Methylated arsenicals were not found in the three plant species exposed to iAs under axenic conditions. Axenically grown rice was able to take up MMA(V) or DMA(V), and reduce MMA(V) to MMA(III) but not convert it to DMA(V). Methylated As was detected in the shoots of soil-grown rice, and in rice grain from nonsterile hydroponic culture. GeoChip analysis of microbial genes in a Bangladeshi paddy soil showed the presence of the microbial As methyltransferase gene arsM. • Our results suggest that plants are unable to methylate iAs, and instead take up methylated As produced by microorganisms.

The nucleotide polymorphisms within the Epstein-Barr virus C and Q promoters from nasopharyngeal carcinoma affect transcriptional activity in vitro.

Epstein-Barr virus (EBV) is a ubiquitous human gamma herpesvirus that is associated with Burkitt's lymphoma (BL), gastric carcinoma, nasopharyngeal carcinoma (NPC), and NK/T-cell lymphoma. Two viral promoters, Cp and Qp, are important for EBV latent infection. The latency Cp, which is used in primary infection, drives expression of the full spectrum of EBV nuclear antigens. Qp is active in EBV-associated tumors and drives the latency I/II expression pattern. In this study, we determined nucleotides polymorphisms in the Cp and Qp promoter regions in peripheral blood mononuclear cells (PBMCs) from Cantonese healthy carriers and in biopsies of NPC, nasal NK/T lymphoma, BL, and gastric carcinoma. The sequence changes of -12G>T and +69 C>T in Cp and -197 G>A and +1 G>C in Qp were frequently identified in NPC. Transient transfection studies using luciferase gene reporters revealed a significant reduction (57.11%) in gene expression from the Cp +69T variant and increased expression (43.5%) from the Qp +1C variant compared to the prototype, suggesting that these sequence variations affect promoter activity. Our results indicate that the nucleotides polymorphisms in Cp and Qp occur frequently in NPC and might contribute to the oncogenesis of EBV.

Heat shock factor 1 upregulates transcription of Epstein-Barr Virus nuclear antigen 1 by binding to a heat shock element within the BamHI-Q promoter.

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) is essential for maintenance of the episome and establishment of latency. In this study, we observed that heat treatment effectively induced EBNA1 transcription in EBV-transformed B95-8 and human LCL cell lines. Although Cp is considered as the sole promoter used for the expression of EBNA1 transcripts in the lymphoblastoid cell lines, the RT-PCR results showed that the EBNA1 transcripts induced by heat treatment arise from Qp-initiated transcripts. Using bioinformatics, a high affinity and functional heat shock factor 1 (HSF1)-binding element within the -17/+4 oligonucleotide of the Qp was found, and was determined by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. Moreover, heat shock and exogenous HSF1 expression induced Qp activity in reporter assays. Further, RNA interference-mediated HSF1 gene silencing attenuated heat-induced EBNA1 expression in B95-8 cells. These results provide evidence that EBNA1 is a new target for the transcription factor HSF1.

[Arsenic speciation in edible plants: a review].

Arsenic (As) is a ubiquitous chemical element in environment, and the increasingly serious As pollution is highly concerned all over the world. China has been considered as one of the countries and regions with serious As pollution in the world by the World Health Organization (WHO). Recent studies indicated that food is one of the major contributors of As in human diets. Edible plants are essential in the diet structure in human life, which often contain high level of As. However, the total As in food can not exactly reflect the toxicity of As, while As speciation closely relates to the As bio-toxicity. Inorganic arsenic is verified as the carcinogen based on human epidemiological data. This paper reviewed the As species in edible plants, their bio-toxicity, and analytical methods.

The enhanced transcriptional activity of the V-val subtype of Epstein-Barr virus nuclear antigen 1 in epithelial cell lines.

The Epstein-Barr virus encoded nuclear antigen 1 (EBNA1) is required for the replication and maintenance of the episomal EBV genome and for the transactivation of viral gene expression. EBNA1 has been classified into five subtypes, among which the V-val subtype was reported to be associated with nasopharyngeal carcinoma (NPC). Here we report a higher transcriptional activity of the V-val subtype of EBNA1 than for the prototype derived from B95.8 cells to transactivate FR-containing luciferase plasmid, which was mainly a consequence of the mutations in the carboxy-terminus of EBNA1. This interpretation was further supported by the finding that the variant form of EBNA1 has a higher binding affinity for the FR sequence than the prototype by electrophoretic mobility shift assays. The functional advantage of the V-val EBNA1 investigated in this study may contribute to the oncogenesis of NPC.

Direct evidence showing the effect of root surface iron plaque on arsenite and arsenate uptake into rice (Oryza sativa) roots.

The present study aimed to investigate the effects of root surface iron plaque on the uptake kinetics of arsenite and arsenate by excised roots of rice (Oryza sativa) seedlings. The results demonstrated that the presence of iron plaque enhanced arsenite and decreased arsenate uptake. Arsenite and arsenate uptake kinetics were adequately fitted by the Michaelis-Menten function in the absence of plaque, but produced poor fits to this function in the presence of plaque. Phosphate in the uptake solution did not have a significant effect on arsenite uptake irrespective of the presence of iron plaque; however phosphate had a significant effect on arsenate uptake. Without iron plaque, phosphate inhibited arsenate uptake. The presence of iron plaque diminished the effect of phosphate on arsenate uptake, possibly through a combined effect of arsenate desorption from iron plaque.