Leaf nutrient resorption of two life-form tree species in urban gardens and their response to soil nutrient availability.

Background: Leaf nutrient resorption is a key strategy in plant conservation that minimizes nutrient loss and enhances productivity. However, the differences of the nutrient resorption among garden tree species in urban ecosystems were not clearly understood, especially the differences of nitrogen resorption efficiency (NRE) and phosphorous resorption efficiency (PRE) between evergreen and deciduous trees. Methods: We selected 40 most generally used garden tree specie belonged two life forms (evergreen and deciduous) and investigated the nitrogen (N) and phosphorus (P) concentrations in green and senesced leaves and soil nutrient concentrations of nine samples trees for each species. Then, the nutrient concentrations and resorption efficiency were compared, and the soil nutrients utilization strategies were further analyzed. Results: The results showed that the N concentration was significantly higher in the green and senesced leaves of deciduous trees than in the leaves of evergreen trees. The two life-form trees were both N limited and evergreen trees were more sensitive to N limitation. The NRE and PRE in the deciduous trees were significantly higher than those in the evergreen trees. The NRE was significantly positively correlated with the PRE in the deciduous trees. As the soil N and P concentrations increased, the nutrient resorption efficiency (NuRE) of the evergreen trees increased, but that of the deciduous trees decreased. Compared with the deciduous trees, the evergreen trees were more sensitive to the feedback of soil N and P concentrations. These findings reveal the N and P nutrient resorption mechanism of evergreen and deciduous trees and fill a gap in the understanding of nutrient resorption in urban ecosystems.

Self-delivery nanomedicine for chemotherapy sensitized photodynamic therapy.

A chlorine e6 (Ce6) and curcumin (Cur) based self-delivery nanomedicine (CeCu) is prepared for chemotherapy sensitized photodynamic therapy (PDT). The chemotherapeutic agent of Cur could inhibit the TrxR activity to destroy the cellular ROS-defence system for enhanced PDT, which provides synergistic effects for tumor precision therapy in consideration of the unfavorable tumor microenvironments.

Determination of MIC Breakpoints for Second-Line Drugs Associated with Clinical Outcomes in Multidrug-Resistant Tuberculosis Treatment in China.

Our study aims to identify the clinical breakpoints (CBPs) of second-line drugs (SLDs) above which standard therapy fails in order to improve multidrug-resistant tuberculosis (MDR-TB) treatment. MICs of SLDs were determined for M. tuberculosis isolates cultured from 207 MDR-TB patients in a prospective cohort study in China between January 2010 and December 2012. Classification and regression tree (CART) analysis was used to identify the CBPs predictive of treatment outcome. Of the 207 MDR-TB isolates included in the present study, the proportion of isolates above the critical concentration recommended by WHO ranged from 5.3% in pyrazinamide to 62.8% in amikacin. By selecting pyrazinamide as the primary node (CBP, 18.75 mg/liter), 72.1% of sputum culture conversions at month four could be predicted. As for treatment outcome, pyrazinamide (CBP, 37.5 mg/liter) was selected as the primary node to predict 89% of the treatment success, followed by ofloxacin (CBP, 3 mg/liter), improving the predictive capacity of the primary node by 10.6%. Adjusted by identified confounders, the CART-derived pyrazinamide CBP remained the strongest predictor in the model of treatment outcome. Our findings indicate that the critical breakpoints of some second-line drugs and PZA need to be reconsidered in order to better indicate MDR-TB treatment outcome.

[Chemical constituents from the twigs and leaves of Harrisonia perforate].

This study was performed to investigate the chemical constituents in the twigs and leaves of Harrisonia perforate. Six compounds were isolated from the 95% EtOH extract of the twigs and leaves of Harrisonia perforate by silica gel, ODS, Sephadex LH-20 column chromatographies and preparative HPLC. On the basis of chemical properties and spectra data, these compounds were identified as harriperfin E (1), kihadanin A (2), kihadanin B (3), 6α-acetoxyobacunol acetate (4), gardaubryone C (5), and ß-sitosterol methyl ether (6), respectively. Compound 1 is a new chromone, and compounds 2-6 are isolated from this plant for the first time.

[Chemical studies on roots of Ficus hirta].

Seventeen compounds were isolated from the 95% ethanolic extract of the root of Ficus hirta. Their structures were identified on the basis of physicochemical properties and spectral data analysis. The structures were elucidated as cyclomorusin (1), 3-O-[(6-O-E-sinapoyl)-beta-D-glucopyranosyl]-(1 --> 2)-beta-D-glucopyranoside (2), 3,5,4'-trihydroxy-6,7,3'-trimethoxyflavone (3), quercetin (4), tricin (5), acacetin (6), luteolin (7), apigenin (8), (E) -suberenol (9), meranzin hydrate (10), methyl eugenol (11), 3-methoxy-4-hydroxybenzoic acid (12), p-hydroxybenzoic acid (13), methyl chlorogenate (14), emodin (15), alpha-amyrin acetate (16), and beta-sitosterol emodin (17), respectively. Compounds 1-6, 9-15 were isolated from this plant for the first time.