Use of physiological activities to estimate the population growth of rotifer (Brachionus calyciflorus) under the stress of toxic Microcystis and nitrite.

Microcystis blooms disrupt aquatic systems and adversely affect zooplankton growth. Brachionus calyciflorus Pallas (rotifer) was introduced to different combinations of toxic Microcystis aeruginosa (0, 2 × 105, 2 × 106, and 2 × 107 cells mL-1) and nitrite (0, 2, 4, and 6 mg L-1) to evaluate their physiological activities and population growth under stress. Survival rate (S), population growth rate (r), grazing rate (G), antioxidant response, and metabolic and digestive enzyme activities were determined. Results revealed that G declined with the increasing nitrite doses and grazing time upon exposure to a certain Microcystis concentration. Toxic M. aeruginosa and nitrite inhibited the S, r, glutathione content, total antioxidant capacity level, and activities of alkaline phosphatase, xanthine oxidase, lactate dehydrogenase, and cellulase (p < 0.05) but increased the reactive oxygen species level, malondialdehyde content, and amylase activity (p < 0.05). The activities of superoxide dismutase, catalase, and pepsase were also increased in single low doses of nitrite solutions (p < 0.05). Therefore, the grazing intensity of rotifers affected B. calyciflorus physiological activities, which are useful in the estimation of its population growth in eutrophic water environments.

Proteomics analysis reveals that foreign cp4-epsps gene regulates the levels of shikimate and branched pathways in genetically modified soybean line H06-698.

Although genetically modified (GM) glyphosate-resistant soybeans with cp4-epsps gene have been widely planted all over the world, their proteomic characteristics are not very clear. In this study, the soybean seeds of a GM soybean line H06-698 (H) with cp4-epsps gene and its non-transgenic counterpart Mengdou12 (M), which were collected from two experiment fields in two years and used as 4 sample groups, were analyzed with label-free proteomics technique. A total of 1706 proteins were identified quantitatively by label-free quantification, and a total of 293 proteins were detected as common differential abundance proteins (DAPs, FC is not less than 1.5) both in two groups or more. Functional enrichment analysis of common DAPs identified from four groups, shows that most up-regulated proteins were clustered into stress response, carbon and energy metabolism, and genetic information processing. Further documentary analysis shows that 15 proteins play important roles in shikimate pathways, reactive oxygen species (ROS) and stress response. These results indicated that the change of protein abundance in different samples were affected by various factors, but except shikimate and branched pathways related proteins, only ROS and stress-related proteins were found to be stably regulated by cp4-epsps gene, and no unexpected and safety-related proteins such as antinutritional factors, allergenic proteins, and toxic proteins were found as DAPs. The influence of foreign genes in genetically modified plants is worthy of attention and this work provides new clues for exploring the regulated proteins and pathways in GM plants.

Efficient X-ray scintillating lead(ii)-based MOFs derived from rigid luminescent naphthalene motifs.

Solid-state X-ray scintillators are widely applied in medical imaging and space exploration. However, it is still a great challenge to probe into the intrinsic nature of scintillating behaviour due to the ambiguous structure-function relationship. Herein, four structure-defined X-ray scintillating Pb(ii)-based metal-organic frameworks (SMOFs) were successfully obtained under solvothermal conditions, [Pb(1,4-ndc)(DMF)]n (SMOF-1), [Pb(1,4-ndc)(DMA)]n (SMOF-2), [Pb2(2,6-ndc)2(H2O)]n·nDMF (SMOF-3) and [Pb4(2,6-ndc)3Cl2]n (SMOF-4), where 1,4-H2ndc = 1,4-naphthalene dicarboxylate, 2,6-H2ndc = 2,6-naphthalene dicarboxylate, DMF = N,N-dimethylformamide, and DMA = N,N-dimethylacetamide. SMOFs 1-4 show scintillating signals under X-rays triggered by a highly purified tungsten target. Compared with SMOFs 1-3, SMOF-4 exhibits excellent scintillating performance owing to its solvent-free and denser structure, which favours more efficient conversion ability of X-rays to visible light. X-ray stimulated luminescence (XSL) spectra present multiple emission peaks, which is further confirmed by wavelength-dependent luminescence spectra under UV-Vis light, and density of state and DFT calculations. The synergistic effects of heavy metal Pb(ii) centres as effective X-ray absorbers and organic ligands as luminescent motifs endow these Pb(ii)-based MOFs with application prospects in X-ray detection.