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Two previously undescribed steroidal saponins, rugosarosides A (1) and B (2), as well as 16 known compounds (3–18), were isolated from the rhizomes of Paris rugosa H. Li & S. Kurita (Melanthiaceae). Their chemical structures were elucidated based on extensive analyses of NMR and MS data and acidic hydrolyses. These isolates were evaluated for their cytotoxicity to five human cancer cell lines (HL-60, SW480, MDA-MB-231, A549, and A549/Taxol) and the normal human bronchial epithelial cell line BEAS-2B using the MTS test. Spirostanol saponins 6 – 12 and furostanol saponin 16 showed cytotoxic activity, with IC 50 values ranging from 0.13 to 3.88 μ M. The furostanol saponins 14 , 15 , and 17 selectively inhibited HL-60, A549, and A549/Taxol cells (IC 50 : 3.45–9.51 μ M), with no cytotoxicity to SW480 and MDA-MB-231 cells (IC 50 > 40 μ M). [Display omitted] • Two previously undescribed steroidal saponins were isolated from Paris rugosa rhizomes. • Seven spirostanol saponins showed inhibitory activity against five human cancer cell lines. • Three furostanol saponins selectively inhibited HL-60, A549, and A549/Taxol cells. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinase (MAPK) cascades are involved in various processes, including plant growth and development as well as biotic and abiotic stress responses. MAPK kinases (MKKs), which link MPKs and MAPKK kinases (MKKKs), are crucial in MAPK cascades because these kinases mediate various stress responses in plants. However, only few MKKs in Brassica campestris (rape) have been functionally characterized. In this study, a novel gene, MKK4 that belongs to a C MKK group, was isolated and characterized from rape. Bioinformatics analysis revealed that the length of cDNA was 1,317 bp with an open reading frame of 993 bp, which encodes a polypeptide containing 330 amino acids, including a putative signal peptide with 27 amino acid residues and a mature protein with 303 amino acids. The obtained MKK4 exhibited a predicted molecular mass of 36.5 kDa and an isoelectric point of 9.01. Quantitative real-time polymerase chain reaction analysis revealed that MKK4 expression could be induced by cold and salt. We also found that the MKK4 protein is localized in the nucleus. In addition, a 999 bp promoter fragment of MKK4 was cloned. Sequence analysis revealed that several putative regulatory elements were found in the MKK4 promoter. Transient expression assay showed that the MKK4 promoter fragments exhibited promoter activity and stimulated GFP expression. The effects of GFP gene expression at different temperatures and in different onion epidermis culture patterns were compared. Results showed that the MKK4 promoter could respond to low temperature and salt stress. These results suggested that MKK4 is possibly important for the regulation of cold- and salt-stress responses in plants. [ABSTRACT FROM AUTHOR]

The damage mechanism of salt stress on plants has attracted much attention. In order to reveal the damage mechanism of different salt stresses, we compared osmotic regulation and photosynthetic characteristics of seedlings of wheat cultivar Xianhan 3 under sodium salt (150 mmol·L -1 ) and calcium salt (5, 30 mmol·L -1 ) treatments alone or in combination. The results showed that sodium salt or calcium salt stress alone significantly inhibited the growth of roots and stems, but increased the amount of soluble sugar and proline, regulatory energy-dissipated electron yield, non-photochemical quenching and relative content of zeaxanthin contents in leaves. In contrast, salt treatments alone significantly decreased the levels of chlorophyll a and chlorophyll b, maximum photochemical efficiency, PSⅡ photochemical efficiency, photochemical quenching and photosynthetic electron transport efficiency. Furthermore, the inhibition of wheat seedling growth was more sensitive to calcium salt than to sodium salt stress, whereas the decreases of chlorophyll content and chlorophyll fluorescence parameters were more prominent in response to sodium salt stress. Except for the amount of soluble protein, lutein and the relative level of zeaxanthin, the changes of other parameters in the leaves due to sodium salt stress were effectively blocked by the application of low calcium concentration, but further increased by the presence of high calcium salt concentration. Taken together, sodium or calcium salt stress alone significantly inhibited seedling growth. The toxicity of sodium salt to wheat seedlings was effectively alleviated by low calcium concentration, but was aggravated by high calcium concentration, which were associated with the changes of photosynthetic pigment content, light energy capture, and photosynthetic electron transport process in the leaves of wheat seedlings. Moreover, osmotic regulators played an important role in enhancing the resistance of wheat seedlings to sodium or/and calcium environment.

To investigate the characteristics of heavy metal pollution caused by traffic and its potential ecological risks, we measured the amount of metal elements in samples collected from a traffic trunk road in Lanzhou City with atomic absorption spectrophotometer. The single factor index method and potential ecological risk index method were used to evaluate the degree of pollution and potential ecological risks, and then the effects of heavy metal pollution on chlorophyll and calcium (Ca) contents in greening plants were analyzed. The results showed that the amount of heavy metals including chromium (Cr), manganese (Mn), zinc (Zn), copper (Cu) and nickel (Ni) in the soils increased significantly, with Cr, Cu and Pb reaching moderate pollution level. The degree of potential ecological risk was Cu>Pb>Cr>Ni>Zn>Mn. Sophora japonica, Rosa chinesis, Prunus ceraifera, and Euonymus japonicas showed different accumulation effects on Pb, Mn, Zn, and Ni. The content of chlorophyll in the leaves of deciduous species S. japonica, R. chinesis and P. ceraifera was higher in the roadside sampling point than that in the control point, while the pattern was just the opposite in evergreen species E. japonicas and P. orientalis. Foliar Ca content of greening plants in the roadside sampling point was higher than that in the control point, suggesting that high chlorophyll and Ca contents might be beneficial to plant survival in the heavy metal contaminated area. Taken together, traffic operation led to the accumulation of heavy metals (Cr, Mn, Zn, Cu, and Ni) in the soil of the study area. S. japonica, R. chinesis, P. ceraifera and E. japonicas could accumulate Pb, Mn, Zn and Ni, which could be used as greening plants in soils polluted by those heavy metals.

Objective: To investigate the influential factors and establish culture method for G. uralensis callus., Methods: To study the possible effective factors of culture condition by comparing with different explants, light, plant hormones and its ratio., Results: The hypocotyl was the best among different explants, its inducing ratios was 94%, and the callus occurred earliest. When the calluses were inoculated on MS + 6 - BA (1.0-2.0) mg/L + NAA (0.5-1.0) mg/L, adventitious buds formed. 2,4-D could induce non-embryogenic callus, the compounding proportions of 6 - BA and NAA could induce embryogenic callus. Light influenced induction and growth of callus., Conclusion: Different explants, components of hormone and light are the influencial factors of callus induction and growth of G. uralensis.