A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls （PCBs） in order to assess the levels of pollution, sources, are...A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls （PCBs） in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% of ∑PCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% of ∑PCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs.展开更多
Reproductive isolation is a fundamental require- ment for speciation and includes several sequential stages. Few studies have determined the relative contributions of pre- and post-zygotic reproductive isolation in pl...Reproductive isolation is a fundamental require- ment for speciation and includes several sequential stages. Few studies have determined the relative contributions of pre- and post-zygotic reproductive isolation in plants, especially between relative species with clear differentiation in flower form. To investigate the mechanisms responsible for repro- ductive isolation in sympatric A4ussaenda pubescens var. alba and Mussaenda shikokiana （Rubiaceae） in Guangxi Province, China, we made observations of flowering phenology, patterns of insect visitation, and conducted pollination experiments, including artificial hybridization. The two species had over- lapping flowering times and were pollinated by overlapping pollinators; however, their relative importance differed significantly with M. pubescens visited more commonly by bees and M. shikokiana more frequently by butterflies. Using vegetative and floral characters and molecular evidence based on nuclear ribosomal internal and external transcribed spacer regions we detected seven naturally occurring hybrids among a sample of approximately 125 individuals. Hybrids were characterized by morphologies that most closely resembled their maternal parents based on chloroplast evidence. Studies of artificially synthesized and natural hybrids demonstrated that hybrid seed had very low germination rates and naturally occurring hybrids exhibited pollen sterility. Post-zygotic reproductive isolating mechanisms play a primary role in limiting gene exchange between co-occurring species and maintaining species integrity in areas of sympatry.展开更多
Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the li...Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the limited experimental data, it is important and necessary to develop structure-based models for prediction of the toxicity of the compounds. In this study, a new molecular structure representation, molecular hologram, was employed to investigate the quantitative relationship between toxicity and molecular structures for 18 PBDEs. The model with the significant correlation and robustness (r <sup>2</sup> = 0.991, q <sup>2</sup> <sub>LOO</sub> = 0.917) was developed. To verify the robustness and prediction capacity of the derived model, 14 PBDEs were randomly selected from the database as the training set, while the rest were used as the test set. The results generated under the same modeling conditions as the optimal model are as follows: r <sup>2</sup> = 0.988, q <sup>2</sup> <sub>LOO</sub> = 0.598, r <sup>2</sup> <sub>pred</sub> = 0.955, and RMSE (root-mean-square of errors) = 0.155, suggesting the excellent ability of the derived model to predict the toxicity of PBDEs. Furthermore, the structural features and molecular mechanism related to the toxicity of PBDEs were explored using HQSAR color coding.展开更多
The exploration and identification of antiproliferative phytochemicals have received increased attention in medicinal chemistry. In particular, research focused on the toxicology of marine natural products has increas...The exploration and identification of antiproliferative phytochemicals have received increased attention in medicinal chemistry. In particular, research focused on the toxicology of marine natural products has increased in recent years. Terpenoids, among many secondary metabolites, have been demonstrated to act as effective anticancer agents. Soft corals, a group of marine invertebrates, produce a variety of terpenoids with biofunctional properties. The current study presents the extraction, purification, and identification of sterol congeners from the soft coral Dendronephthya putteri. The method involves 50% chloroform-methanol extraction, polar column fractionation, and analysis through GC-MSn. Dose-dependent antiproliferative activity was observed within the sterol-rich fraction (DPCMH 2-4), which consisted of 3β-hydroxy-Δ5-steroidal congeners. This fraction inhibited the growth of HL-60 and MCF-7 cells with IC50 values of 25.27±1.43 and 22.81±0.15 μg/mL, respectively. Apoptotic body formation, DNA damage, cell cycle arrest, and apoptotic cell signaling pathway activation were also observed, reinforcing the dose-dependent antiproliferative and apoptosis-inducing activity of 3β-hydroxy-Δ5-steroidal congeners. To our knowledge, this is the first report of anticancer agent identification from the soft coral D. putteri. Based on the observations, these steroidal congeners are promising candidates for the development of anticancer drugs.展开更多
Polychlorinated biphenyl (PCBs) congeners were measured in (unwashed) whole-body field (deer) mice (Peromyscus maniculaltus) collected directly upgradient from a sediment retention structure (weir) within Los Alamos C...Polychlorinated biphenyl (PCBs) congeners were measured in (unwashed) whole-body field (deer) mice (Peromyscus maniculaltus) collected directly upgradient from a sediment retention structure (weir) within Los Alamos Canyon (LAC), Los Alamos National Laboratory (LANL), New Mexico, USA, from 2007 through 2013. Samples were also collected approximately 8 km downgradient of the retention structure in 2009 and 2013. LAC, a major drainage that crosses LANL lands, contains legacy waste, including PCBs, and occasionally discharges storm water and snowmelt flows to the Rio Grande approximately 8.8 km away from the weir. The Rio Grande is the major waterway that flows southward across the state. The weir was constructed across the channel on the northeastern boundary of LANL in late 2000 to help contain sediments mobilized by floodwaters as a result of a large wildfire in early 2000 that burned forest lands west and adjacent to LANL. Total PCBs in field mice directly upgradient of the sediment retention structure from 2007 through 2012 were significantly greater (p 0.05) than in field mice collected from background locations but decreased in concentration over time;by 2013 the levels were statistically similar (p > 0.05) to background. The highest mean total PCB concentration in field mice was below the levels that may negatively impact field mice population attributes. Total PCBs in field mice collected 8 km below the sediment retention structure in 2009 were lower than field mice collected from behind the weir and decreased over time;also by 2013, the amount of PCBs in field mice 8 km below the sediment retention structure were not significantly different (p > 0.05) from background. The rank order of concentrations of ICES 7 PCB congeners in upgradient and downgradient field mice were: No. 153 > 180 > 138 > 118 > 28 > 101 > 52 and No. 153 > 180 > 138 > 52 > 101 > 118 > 28, respectively. Based on the PCB homolog distribution, the major formulation detected in field mice was Aroclor-1260. Overall, the reduction of PCBs in 展开更多
Endocrine disrupting chemicals (EDCs) in the natural environment exhibit a unique non-monotonic dose-response curve and it is impossible to select one simple index to characterize the bilogogical activity of these com...Endocrine disrupting chemicals (EDCs) in the natural environment exhibit a unique non-monotonic dose-response curve and it is impossible to select one simple index to characterize the bilogogical activity of these compounds. Quantitative structure-activity relationship (QSAR) study on non-monotonic dose-response curve has become a real challenge presently. In order to explore the possible mechanism for the non-monotonic dose-response curve of polychlorinated biphenyls congeners (PCBs) in chicken embryo hepatocyte bioassay, AM1 method of ChemOffice was adopted to calculate necessary structure descriptors for PCBs, while the interactions between PCBs and simulated AhR ligand binding domain (LBD) were analyzed by using FlexX in SYBYL7.0. Different binding modes for PCBs have been distinguished not only from aligned conformation but also from free binding energy. Some QSAR models were established separately for both low and high doses ranges, revealing that receptor binding may predominate in the interference of the physiological function of cytochrome P4501A-P4501A in the low doses range. But with the higher doses range, the EROD suppression might be related to acute toxicity owing to molecular polarity or distribution of charges and consequently damage structure and function of chicken embryo hepatocyte.展开更多
The aim of this work was to study the reactions of wheat （T. aestivum L.） and its wild congeners under salt stress. Physiological mechanisms that underlie traits for salt tolerance plantlets have been used to test s...The aim of this work was to study the reactions of wheat （T. aestivum L.） and its wild congeners under salt stress. Physiological mechanisms that underlie traits for salt tolerance plantlets have been used to test some wheat species and to identify sources of salty tolerance. Stress conditions were founded by means of exposure of the plantlets in NaCI water solution, 1.68% that demonstrably differentiates the samples by growth parameters. Under laboratory conditions the ability of seedlings to bear a significant shortage of water, their ability to accumulate biomass, changing the parameters of linear growth processes and changes in water content in leaves and roots of seedlings under stress was determined. Interest is also the rate of growth of root fibrils in saline conditions. These experiments allowed to provide a comprehensive diagnosis of studied forms of wheat and make an initial opinion on their salt tolerance. Different features of abiotic stress responses of some wheat species at the early stages of development were shown that testifies necessi~ of great number of approaches at selection of genetic material for improvement of modern wheat eultivars. This work is the first phase of research for practical breeding.展开更多
Purpose of this work was to study changes in the ion balance under salt stress in roots and leaves of seedlings of T. aestivum L. and its wild congeners with different genomic composition. Laboratory assessment of sal...Purpose of this work was to study changes in the ion balance under salt stress in roots and leaves of seedlings of T. aestivum L. and its wild congeners with different genomic composition. Laboratory assessment of salt tolerance in seedlings was carried out and contents of ions K^＋, Na^＋ and Ca^2＋ in roots and leaves were defined. Considerable change of ionic balance in roots and leaves of studied forms of wheat against salt stress is shown. It is noticed that the parity K^＋/Na^＋ decreases in process of strengthening of salt stress. Authentic negative correlation between a relative gain of a biomass of leaves and roots in the stress conditions and accumulation of ions Na^＋ and between a relative gain of a biomass of leaves in the stress conditions and a parity in them of ions K^＋/Na^＋ is revealed. The research results also show that the stability characteristics of indicators of changes in ionic composition or balance in the leaves of young plants are more informative than in the roots and allow to reveal the form, characterized by relatively high of K^＋/Na^＋ ratio and the relatively low accumulation of Ca2^＋ as the most resistant to salt stress.展开更多
A stereoselective and regiospecific synthesis of procursors(2),(4),(6)and(7)of prostacyclin analogues from 2,3-epoxylbicyclo[3.2.0]hept-6-one(1)are described.
基金Project supported by the National Basic Research Program (973) of China(No. 2002CB410810).
文摘A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls （PCBs） in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% of ∑PCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% of ∑PCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs.
基金supported by the National Natural Science Foundation of China (31170184, U1202261, 31000109)the China Scholarship Council (for C. S.’s study in Canada)
文摘Reproductive isolation is a fundamental require- ment for speciation and includes several sequential stages. Few studies have determined the relative contributions of pre- and post-zygotic reproductive isolation in plants, especially between relative species with clear differentiation in flower form. To investigate the mechanisms responsible for repro- ductive isolation in sympatric A4ussaenda pubescens var. alba and Mussaenda shikokiana （Rubiaceae） in Guangxi Province, China, we made observations of flowering phenology, patterns of insect visitation, and conducted pollination experiments, including artificial hybridization. The two species had over- lapping flowering times and were pollinated by overlapping pollinators; however, their relative importance differed significantly with M. pubescens visited more commonly by bees and M. shikokiana more frequently by butterflies. Using vegetative and floral characters and molecular evidence based on nuclear ribosomal internal and external transcribed spacer regions we detected seven naturally occurring hybrids among a sample of approximately 125 individuals. Hybrids were characterized by morphologies that most closely resembled their maternal parents based on chloroplast evidence. Studies of artificially synthesized and natural hybrids demonstrated that hybrid seed had very low germination rates and naturally occurring hybrids exhibited pollen sterility. Post-zygotic reproductive isolating mechanisms play a primary role in limiting gene exchange between co-occurring species and maintaining species integrity in areas of sympatry.
基金Supported by the Key Project of the National Natural Science Foundation of China (Grant No. 20737001)the National Natural Science Foundation Key Project of China (Grant No. 20737001)the Science and Technology Development Founda-tion Project of Nanjing Medical University (Grant No. 06NMUM021)
文摘Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the limited experimental data, it is important and necessary to develop structure-based models for prediction of the toxicity of the compounds. In this study, a new molecular structure representation, molecular hologram, was employed to investigate the quantitative relationship between toxicity and molecular structures for 18 PBDEs. The model with the significant correlation and robustness (r <sup>2</sup> = 0.991, q <sup>2</sup> <sub>LOO</sub> = 0.917) was developed. To verify the robustness and prediction capacity of the derived model, 14 PBDEs were randomly selected from the database as the training set, while the rest were used as the test set. The results generated under the same modeling conditions as the optimal model are as follows: r <sup>2</sup> = 0.988, q <sup>2</sup> <sub>LOO</sub> = 0.598, r <sup>2</sup> <sub>pred</sub> = 0.955, and RMSE (root-mean-square of errors) = 0.155, suggesting the excellent ability of the derived model to predict the toxicity of PBDEs. Furthermore, the structural features and molecular mechanism related to the toxicity of PBDEs were explored using HQSAR color coding.
基金Supported by the "Regional Specialized Industry Development Program",Ministry of Trade,Industry,and Energy(MOTIE),Koreasupervised by the Korea Institute for Advancement of Technology(KIAT)
文摘The exploration and identification of antiproliferative phytochemicals have received increased attention in medicinal chemistry. In particular, research focused on the toxicology of marine natural products has increased in recent years. Terpenoids, among many secondary metabolites, have been demonstrated to act as effective anticancer agents. Soft corals, a group of marine invertebrates, produce a variety of terpenoids with biofunctional properties. The current study presents the extraction, purification, and identification of sterol congeners from the soft coral Dendronephthya putteri. The method involves 50% chloroform-methanol extraction, polar column fractionation, and analysis through GC-MSn. Dose-dependent antiproliferative activity was observed within the sterol-rich fraction (DPCMH 2-4), which consisted of 3β-hydroxy-Δ5-steroidal congeners. This fraction inhibited the growth of HL-60 and MCF-7 cells with IC50 values of 25.27±1.43 and 22.81±0.15 μg/mL, respectively. Apoptotic body formation, DNA damage, cell cycle arrest, and apoptotic cell signaling pathway activation were also observed, reinforcing the dose-dependent antiproliferative and apoptosis-inducing activity of 3β-hydroxy-Δ5-steroidal congeners. To our knowledge, this is the first report of anticancer agent identification from the soft coral D. putteri. Based on the observations, these steroidal congeners are promising candidates for the development of anticancer drugs.
文摘Polychlorinated biphenyl (PCBs) congeners were measured in (unwashed) whole-body field (deer) mice (Peromyscus maniculaltus) collected directly upgradient from a sediment retention structure (weir) within Los Alamos Canyon (LAC), Los Alamos National Laboratory (LANL), New Mexico, USA, from 2007 through 2013. Samples were also collected approximately 8 km downgradient of the retention structure in 2009 and 2013. LAC, a major drainage that crosses LANL lands, contains legacy waste, including PCBs, and occasionally discharges storm water and snowmelt flows to the Rio Grande approximately 8.8 km away from the weir. The Rio Grande is the major waterway that flows southward across the state. The weir was constructed across the channel on the northeastern boundary of LANL in late 2000 to help contain sediments mobilized by floodwaters as a result of a large wildfire in early 2000 that burned forest lands west and adjacent to LANL. Total PCBs in field mice directly upgradient of the sediment retention structure from 2007 through 2012 were significantly greater (p 0.05) than in field mice collected from background locations but decreased in concentration over time;by 2013 the levels were statistically similar (p > 0.05) to background. The highest mean total PCB concentration in field mice was below the levels that may negatively impact field mice population attributes. Total PCBs in field mice collected 8 km below the sediment retention structure in 2009 were lower than field mice collected from behind the weir and decreased over time;also by 2013, the amount of PCBs in field mice 8 km below the sediment retention structure were not significantly different (p > 0.05) from background. The rank order of concentrations of ICES 7 PCB congeners in upgradient and downgradient field mice were: No. 153 > 180 > 138 > 118 > 28 > 101 > 52 and No. 153 > 180 > 138 > 52 > 101 > 118 > 28, respectively. Based on the PCB homolog distribution, the major formulation detected in field mice was Aroclor-1260. Overall, the reduction of PCBs in
基金Supported by the National Natural Science Foundation of China(Grant Nos. 20777035 & 20737001) 863 Advanced Research Project (Grant Nos. 2007AA06Z416, 2006AA06Z424 & 2007AA06A405)
文摘Endocrine disrupting chemicals (EDCs) in the natural environment exhibit a unique non-monotonic dose-response curve and it is impossible to select one simple index to characterize the bilogogical activity of these compounds. Quantitative structure-activity relationship (QSAR) study on non-monotonic dose-response curve has become a real challenge presently. In order to explore the possible mechanism for the non-monotonic dose-response curve of polychlorinated biphenyls congeners (PCBs) in chicken embryo hepatocyte bioassay, AM1 method of ChemOffice was adopted to calculate necessary structure descriptors for PCBs, while the interactions between PCBs and simulated AhR ligand binding domain (LBD) were analyzed by using FlexX in SYBYL7.0. Different binding modes for PCBs have been distinguished not only from aligned conformation but also from free binding energy. Some QSAR models were established separately for both low and high doses ranges, revealing that receptor binding may predominate in the interference of the physiological function of cytochrome P4501A-P4501A in the low doses range. But with the higher doses range, the EROD suppression might be related to acute toxicity owing to molecular polarity or distribution of charges and consequently damage structure and function of chicken embryo hepatocyte.
文摘The aim of this work was to study the reactions of wheat （T. aestivum L.） and its wild congeners under salt stress. Physiological mechanisms that underlie traits for salt tolerance plantlets have been used to test some wheat species and to identify sources of salty tolerance. Stress conditions were founded by means of exposure of the plantlets in NaCI water solution, 1.68% that demonstrably differentiates the samples by growth parameters. Under laboratory conditions the ability of seedlings to bear a significant shortage of water, their ability to accumulate biomass, changing the parameters of linear growth processes and changes in water content in leaves and roots of seedlings under stress was determined. Interest is also the rate of growth of root fibrils in saline conditions. These experiments allowed to provide a comprehensive diagnosis of studied forms of wheat and make an initial opinion on their salt tolerance. Different features of abiotic stress responses of some wheat species at the early stages of development were shown that testifies necessi~ of great number of approaches at selection of genetic material for improvement of modern wheat eultivars. This work is the first phase of research for practical breeding.
文摘Purpose of this work was to study changes in the ion balance under salt stress in roots and leaves of seedlings of T. aestivum L. and its wild congeners with different genomic composition. Laboratory assessment of salt tolerance in seedlings was carried out and contents of ions K^＋, Na^＋ and Ca^2＋ in roots and leaves were defined. Considerable change of ionic balance in roots and leaves of studied forms of wheat against salt stress is shown. It is noticed that the parity K^＋/Na^＋ decreases in process of strengthening of salt stress. Authentic negative correlation between a relative gain of a biomass of leaves and roots in the stress conditions and accumulation of ions Na^＋ and between a relative gain of a biomass of leaves in the stress conditions and a parity in them of ions K^＋/Na^＋ is revealed. The research results also show that the stability characteristics of indicators of changes in ionic composition or balance in the leaves of young plants are more informative than in the roots and allow to reveal the form, characterized by relatively high of K^＋/Na^＋ ratio and the relatively low accumulation of Ca2^＋ as the most resistant to salt stress.
文摘A stereoselective and regiospecific synthesis of procursors(2),(4),(6)and(7)of prostacyclin analogues from 2,3-epoxylbicyclo[3.2.0]hept-6-one(1)are described.
