Discovery of a Broad-Spectrum Fluorogenic Agonist for Strigolactone Receptors through a Computational Approach.

Strigolactones (SLs) are plant hormones that play various roles in plant physiology, including provoking the germination of parasitic weeds Orobanche and Striga. A family of α/ß-hydrolases have been proposed to be the SL receptor proteins. Effective assays for measuring the activity of SL receptors could promote the development of SL-related biology and chemistry. In this study, we developed a new approach called pharmacophore-linked probe virtual screening (PPVS). Its application yielded an effective "off-on" probe named Xilatone Red (XLR). This probe showed a broad spectrum and excellent sensitivity toward SL receptors, including ShD14 (Striga D14), for which the detection limit was determined to be in the micromolar range, outperforming that of the commercial fluorogenic agonist Yoshimulactone Green (YLG). Upon hydrolysis by SL receptors, XLR provided fluorogenic and colorimetric signaling responses. Furthermore, XLR could induce germination of Phelipanche aegyptiaca seeds and prevent Arabidopsis max4-1 branching defects at micromolar concentrations. Our molecular simulations revealed the essential factors in the molecular perception of XLR. We anticipate that this study can prompt the discovery of high-performance SL agonists/antagonists to combat parasitic weeds.

Improved adsorption and degradation performance by S-doping of (001)-TiO2.

In this work, sulfur-doped (S-doped) TiO2 with the (001) face exposed was synthesized by thermal chemical vapor deposition at 180 or 250 °C using S/Ti molar ratios R S/Ti of 0, 0.5, 1, 2, 3, 4 and 5. The S-doped samples synthesized at 250 °C exhibit a significantly improved photocatalytic performance. More precisely, S-doping has the following effects on the material: (1) S can adopt different chemical states in the samples. Specifically, it exists in the form of S2- replacing O2- at a ratio of R S/Ti = 1 and also in the form of S6+ replacing Ti4+ at R S/Ti ≥ 2. As a result, S-doping causes a lattice distortion, because the ionic radii of S2- and S6+ differ from that of the O2- and Ti4+ ions. (2) S-doping increases the adsorption coefficient A e for methylene blue (MB) from 0.9% to 68.5% due to the synergistic effects of the oxygen vacancies, increased number of surface chemical adsorption centers as a result of SO4 2- adsorption on the TiO2 surface and the larger pore size. (3) S-doping increases the MB degradation rate from 6.9 × 10-2 min-1 to 18.2 × 10-2 min-1 due to an increase in the amount of •OH and •O2- radicals.

[Reconstruction of critical sized calvarial defects by porous nano-hydroxyapatite/polyamide 6 composite with bone marrow mesenchymal stem cells in rat].

OBJECTIVE: To evaluate the effects of the nano-hydroxyapatite/polyamide 6 (n-HA/PA6) on the proliferation and osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSCs), and the feasibility of using both for constructing tissue engineered bone in the calvarias of rats with critical sized defects. METHODS: The third passage of BMSCs were cultured in osteoblastic medium and seeded on the scaffolds of n-HA/PA6, the proliferation of the BMSCs was tested by MTT (3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium-bromide) on scheduled dates, and the osteoblastic differentiation of the BMSCs were measured by alkaline phosphatase (ALP) staining. Furthermore, the scaffolds with or without BMSCs in rat calvarial defects, after 4 weeks, 8 weeks, and 16 weeks have been implanted. Histology and scanning electron microscope were used to test the bone healing in the different groups. RESULTS: The BMSCs seeded on the n-HA/PA6 grew well, the proliferation of cells was not affected by the scaffold, and the staining of ALP was also positive. At 4 week and 8 week after implantation, the n-HA/PA6 with BMSCs showed more new bone formation on the surface of scaffolds, with a better osseointegration of implant and host bone when compared with the group of n-HA/PA6 without BMSCs. However, there was no significant difference between these two groups at 16 week. CONCLUSION: The porous n-HA/PA6 has no negative effects on the proliferation and osteoblastic differentiation of rat BMSCs, and using BMSCs as seed cells and n-HA/PA6 as scaffolds is a good choice for constructing tissue engineered bone due to the enhanced new bone formation and osseointegration.

[Osteoblastic differentiation and gene expression profile change in rat bone marrow mesenchymal stem cells after a single period of mechanical strain].

OBJECTIVE: To evaluate the osteoblastic differentiation and compare the difference in the gene expression of rat bone marrow mesenchymal stem cells (MSCs) affected by a single period of mechanical strain. METHODS: Bone marrow MSCs were harvested from the femurs and tibiae of SD rats and cultured in vitro. A four-point bending apparatus were used to perform a single 40-minute period of 2,000 microepsilon mechanical strain on these MSCs. The proliferation of the MSCs was tested by MTT on scheduled date, and the osteoblastic differentiation of the MSCs was measured by testing the expression of osteocalcin and alkaline phosphate (ALP) activity of these cells. In addition, we have investigated the possible mechanisms underlying the action of the single 40-minute period of 2,000 microepsilon mechanical strain on these MSCs, after profile blotted and handled by bioinformation, the gene expressions of these two periods of MSCs were examined. RESULTS: The MSCs have grown well in vitro. Our experiment showed that mechanical environment did not weaken the proliferation of the MSCs. However, the ALP activity and the expression of osteocalcin were significantly up-regulated by the 2,000 microepsilon mechanical strain. Using the 27 K Rat Genome Array, 416 different expressions were found. The rate of different genes was 2.8%, of which the expressions of 247 genes increased (61 genes remarkably increased) and 169 genes decreased (74 genes remarkably decreased) in these two periods of MSCs. CONCLUSION: Mechanical strain induced the osteoblastic differentiation of the MSCs, which may be attributed to the different gene levels.

[Effect of different plant growth regulators on transplanting survival ratio of Haloxylon ammodendron seedling and parasitic ratio of Cistanche deserticola].

OBJECTIVE: To study the effect of different plant growth regulators on the transplanting survival ratio of Haloxylon ammodendron seedlings and parasitic ratio of Cistanche deserticola. METHODS: Different combinations of PDJ and rooting powder were used for rooting soaking with Haloxylon ammodendron seedlings, then the survival ratio of Haloxylon ammodendron and parasitic conditions of Cistanche deserticola were statistical analyzed by SAS software. RESULTS: PDJ had promotable effect on the inoculating survival ratio of Haloxylon ammodendron and the parasitic ratio, parasitic number and size of Cistanche deserticola, but had no significant effect on the transplanting survival ratio. High concentration of PDJ (1 x 10(-5) mol/L) and rooting powder treatment improved the inoculation survival ratio, and low concentration of PDJ (1 x 10(6) mol/L) treatment improved the parasitic ratio of Cistanche deserticola, but PDJ with rooting powder treatment had inhibitive effect on the parasitism of Cistanche deserticola. Principal component analysis showed that the transplanting survival ratio, inoculating survival ratio, parasitic ratio and the parasited number of Cistanche deserticola could be taken to evaluate the effect of different plant growth regulators, and the comprehensive effect was the best with PDJ treatment. CONCLUSION: Rooting soaking with PDJ can be used to improve the survival ratio of Haloxylon ammodendron seedling and parasitic ratio of Cistanche deserticola.

[Clinical analysis of maxillofacial patients with diabetes on perioperative period].

OBJECTIVE: To investigate the treatment of perioperative period on maxillofacial patients with diabetes. METHODS: The retrospective analysis was taken on clinical data of 24 cases of maxillofacial patients with diabetes. RESULTS: All patients recovered without severe complications by controlling blood sugar during whole stage and preventing infection with antibiotics after surgery. The wounds in 21 cases healed in 10-14 days after the operations and that didn't in 3 cases. With the treatment on local wounds, the wounds in 3 cases healed in 14-28 days after the operations. CONCLUSION: It's the treatment principle of maxillofacial surgical patients with diabetes to monitor the levels of blood glucose on time, to control the levels of blood glucose rigorously at the whole stage and to prevent complication.

Rhizobialide: a new stearolactone produced by Mesorhizobium sp. CCNWGX022, a rhizobial endophyte from Glycyrrhiza uralensis.

The endophytic strain Mesorhizobium sp. CCNWGX022 was isolated from licorice (Glycyrrhiza uralensis Fisch.) grown in the arid and semi-arid regions of Northwest China. The new stearic acid derived gamma-lactone 1, named rhizobialide (= (5S)-4,5-dihydro-5-(8-oxotetradecyl)furan-2(3H)-one), was isolated from the petroleum-ether extract of the fermentation broth of this strain. The structure of 1 was elucidated on the basis of spectroscopic and mass-spectrometric analysis. This is the first report of this type of compound from rhizobia.