Chemical composition of the essential oil of whole plant of Elsholtizia dense Benth and its anti-tumor effect on human hepatoma cells

Purpose: To determine the chemical components of the essential oil of Elsholtizia dense in Sichuan Province and evaluate the effect of the oil on human hepatoma cells (SMMC-7721) in vitro.Methods: The essential oil was extracted using the modified steam-distillation  extraction method, and its chemical components were determined by gas  chromatography-mass spectrometry (GC-MS). The effect of the essential oil on proliferation of SMMC-7721 cells was studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, with L02 and HeLa cells serving as control groups.Results: GC-MS results show that the essential oil of E. dense contains 40  components. Thirty seven components were identified and accounted for 98.39 % of the essential oil. The two main components were rosefuran epoxide (53.12 %) and 2-ethyl imidazole (29.8 %). The oil significantly inhibited cell proliferation in a concentration- and time-dependent manner (p < 0.05). SMMC-7721 cells were more inhibited than L02 and HeLa cells by the oil, with half maximal inhibitory concentration (IC50) values of 26.23 and 25.46 μg/mL after 8-h and 24-h treatments, respectively.Conclusion: Out of the 40 chemical components of the essential oil of E. dense, rosefuran epoxide and 2-ethyl imidazole were the most abundant. The oil has a significant anti-tumor effect on SMMC-7721 cells, and thus has a potential to be developed as an anti-liver cancer drug.Keywords: Medicinal herb, Elsholtizia dense Benth, Essential oil, Rosefuran epoxide, 2-Ethyl imidazole, Anti-tumor activit

Effects of alkyl ether amine and calcium ions on fine quartz flotation and its guidance for upgrading vanadium from stone coal

Great progress has been made in reverse flotation of fine quartz, especially many new reagents were proved their excellent effects. However, the influences of complex flotation system on fine quartz flotation still need to be scrutinized. In this study, alkyl ether amine (Flotigam EDA-C from Clariant) was used as a collector for the flotation of quartz. It shows better collectability for the flotation of quartz at about pH 10.0 (±0.2). The adsorption mechanism of EDA-C on quartz and the influence of calcium ions on the flotation of quartz were investigated by adsorption tests, zeta-potential measurements, FTIR spectra measurements, X-ray photoelectron spectroscopic and atomic force microscopy imaging. Results show that EDA-C adsorbs on the quartz surface in physical adsorption with no new products, changing its zeta potentials and increasing its hydrophobicity. Calcium ion concentration of 20 mg/L, 40 mg/L, 60 mg/L and 1 g/L can inhibit the quartz surface strongly and decrease its recovery sharply. Inhibition action of 2 g/L Ca decreased, even disappeared when the collector concentration increased to 90 mg/L. Calcium ions changed the chemical environment of Si atoms and O1s on the quartz surface. After positively charged CaOH adsorbed on quartz surface, the amount of EDA-C adsorbed on quartz surface and the recovery decreased. It was greatly inspired to explore quartz separation application from these results

3D spatial distribution of soil pollutants based on geo-shadowing anisotropic RBF-PCA

Research on soil contamination has become increasingly important, but there is limited information about where to sample for pollutants. Thus, the use of three-dimensional (3D) spatial interpolation techniques has been promoted in this area of study. However, the application of traditional interpolation methods is limited in geography, especially in the expression of anisotropy, and it is not associated with geographical properties. To address this issue, we used a test site (a factory in Nanjing) to develop a new research method based on the geographical shading radial basis function (RBF) interpolation method, which considers 3D anisotropy and geographical attribute expression. Drilling and uniform sampling were used to sample the contaminated area at this test site. This approach included two steps: i) An ellipsoid with anisotropic properties was constructed. Thus, the first step was to determine the shape of the ellipsoid using principal component analysis (PCA) to determine the main orientations and construct a rotational and stretched matrix. The second step was determining the ellipsoid size by computing the range using the variogram method for orientations. ii) During field measurement, the geospatial direction influences soil attribute values, so a shadowing calculation method was derived for quadratic weight determination. Then, the weight of the attribute value of known points can be assigned to meet the field conditions. Lastly, the model was evaluated using the root mean square error (RMSE). For the 2D space, the RMSE values of Kriging, RBF, and the proposed method are 6.09, 7.12, and 5.02, respectively. The R2 values of Kriging, RBF, and the proposed method are 0.871, 0.832, and 0.946, respectively. For the 3D space, the RMSE values of Kriging, RBF, and the proposed method are 2.65, 2.23, and 2.58, respectively. The R2 values of Kriging, RBF, and the proposed method are 0.934, 0.912, and 0.953, respectively. The resulting fitted model was relatively smooth and met experimental needs. Thus, we believe that the interpolation method can be applied as a new method to predict the distribution of soil pollutants

Application of CRISPR-Cas12a temperature sensitivity for improved genome editing in rice, maize, and Arabidopsis

Abstract Background CRISPR-Cas12a (formerly Cpf1) is an RNA-guided endonuclease with distinct features that have expanded genome editing capabilities. Cas12a-mediated genome editing is temperature sensitive in plants, but a lack of a comprehensive understanding on Cas12a temperature sensitivity in plant cells has hampered effective application of Cas12a nucleases in plant genome editing. Results We compared AsCas12a, FnCas12a, and LbCas12a for their editing efficiencies and non-homologous end joining (NHEJ) repair profiles at four different temperatures in rice. We found that AsCas12a is more sensitive to temperature and that it requires a temperature of over 28 °C for high activity. Each Cas12a nuclease exhibited distinct indel mutation profiles which were not affected by temperatures. For the first time, we successfully applied AsCas12a for generating rice mutants with high frequencies up to 93% among T0 lines. We next pursued editing in the dicot model plant Arabidopsis, for which Cas12a-based genome editing has not been previously demonstrated. While LbCas12a barely showed any editing activity at 22 °C, its editing activity was rescued by growing the transgenic plants at 29 °C. With an early high-temperature treatment regime, we successfully achieved germline editing at the two target genes, GL2 and TT4, in Arabidopsis transgenic lines. We then used high-temperature treatment to improve Cas12a-mediated genome editing in maize. By growing LbCas12a T0 maize lines at 28 °C, we obtained Cas12a-edited mutants at frequencies up to 100% in the T1 generation. Finally, we demonstrated DNA binding of Cas12a was not abolished at lower temperatures by using a dCas12a-SRDX-based transcriptional repression system in Arabidopsis. Conclusion Our study demonstrates the use of high-temperature regimes to achieve high editing efficiencies with Cas12a systems in rice, Arabidopsis, and maize and sheds light on the mechanism of temperature sensitivity for Cas12a in plants

A large-scale whole-genome sequencing analysis reveals highly specific genome editing by both Cas9 and Cpf1 (Cas12a) nucleases in rice

Targeting specificity has been a barrier to applying genome editing systems in functional genomics, precise medicine and plant breeding. In plants, only limited studies have used whole-genome sequencing (WGS) to test off-target effects of Cas9. The cause of numerous discovered mutations is still controversial. Furthermore, WGS-based off-target analysis of Cpf1 (Cas12a) has not been reported in any higher organism to date. We conduct a WGS analysis of 34 plants edited by Cas9 and 15 plants edited by Cpf1 in T0 and T1 generations along with 20 diverse control plants in rice. The sequencing depths range from 45× to 105× with read mapping rates above 96%. Our results clearly show that most mutations in edited plants are created by the tissue culture process, which causes approximately 102 to 148 single nucleotide variations (SNVs) and approximately 32 to 83 insertions/deletions (indels) per plant. Among 12 Cas9 single guide RNAs (sgRNAs) and three Cpf1 CRISPR RNAs (crRNAs) assessed by WGS, only one Cas9 sgRNA resulted in off-target mutations in T0 lines at sites predicted by computer programs. Moreover, we cannot find evidence for bona fide off-target mutations due to continued expression of Cas9 or Cpf1 with guide RNAs in T1 generation. Our comprehensive and rigorous analysis of WGS data across multiple sample types suggests both Cas9 and Cpf1 nucleases are very specific in generating targeted DNA modifications and off-targeting can be avoided by designing guide RNAs with high specificity.https://doi.org/10.1186/s13059-018-1458-