Response of under-ground bud bank to degradation in an alpine meadows on the Qinghai-Tibet Plateau, China.

Exploring the diversity and formation mechanism of under-ground bud banks is essential for understanding the renewal of plant populations and community succession. However, there are few studies on the response of bud bank size and composition to different degradation gradients in alpine meadows. In view of this, we investigated the size and composition of bud bank under four degradation gradients (non-degraded:ND, lightly degraded:LD, moderately degraded:MD, and heavily degraded:HD) caused by overgrazing in a typical alpine meadow in Tibet, China, using a unit area excavation sampling method, and analyzed the correlation between above-ground plant community composition and bud bank density.

[Effect of restoration types on the community structure of microbes harboring and genes in alpine meadow].

Biological nitrogen (N) fixation and organic N degradation are the main sources of soil available N, while microorganisms driving such processes play an important role in soil N supply and the maintenance of soil fertility. In this study, real-time quantitative PCR and amplicon sequencing technology were used to examine the effects of restoration types on the community structure of N-fixing and chitin-degrading bacteria harboring and genes, respectively, and the gene abundance under four meadows (undisturbed, grazing, fencing, and fencing + reseeding mea-dows) in Qinghai-Tibet Plateau. The results showed that the abundance of and in the four meadows followed the order of undisturbed meadow > grazed meadow > fencing meadow > fencing + reseeding meadow.

Sensitive Tumor Cell Line for Annonaceous Acetogenins and High Therapeutic Efficacy at a Low Dose for Choriocarcinoma Therapy.

Annonaceous acetogenins (ACGs) have attracted much attention because of excellent antitumor activity. However, the lack of selectivity and the accompanying serious toxicity have eventually prevented ACGs from entering clinical application. To decrease the side effects of ACGs, the cytotoxicity of ACGs on 10 types of tumor cell lines was investigated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) test to identify one that was very sensitive to ACGs.

[Plant community and soil nutrient of alpine meadow in different degradation stages on the Tibetan Plateau, China.].

We examined soil physical and chemical properties and plant community characteristics of four alpine meadows at different degradation stages in Damxung County, Lhasa City, Tibet Autonomous Region, China, with the method of spatial sequence instead of time succession. The results showed that soil organic carbon, total nitrogen, available phosphorus, available potassium, ammonium, nitrate, and water content showed a decreasing trend as the degree of soil degradation increased, while pH showed an increasing trend. Plant community height, richness, diversity index and evenness index of the moderately degraded meadow were the highest.

Combined administration on You-Gui Yin and low-dose Raloxifene partially attenuates the bone loss in ovariectomized mice through the proliferation and osteogenic differentiation of bone marrow stromal cells.

Background: Osteoporosis is a systemic skeletal disease of fragility fractures due to the loss of mass and deterioration of the microarchitecture of bone.

Purpose: The aim of the study was to assess the osteogenic effects and the underlying mechanisms of the combined administration of You-Gui Yin (YGY) and Raloxifene hydrochloride (RLX) in ovariectomized (OVX) mice.

Methods: First, a classic animal model was used to mimic postmenopausal osteoporosis through the removal of the ovary of mice.

[Preliminary study on synthesis of novel amphiphilic molecules and their application as drug vectors].

Objective: To synthesize three amphiphilic molecules (TEG-R1, TEG-R2, TEG-R3), with branched oligo polyethylene glycol as hydrophilic fractions and aliphatic chains (containing six, eight and twelve carbon atoms respectively) as hydrophobic fractions, and study them as insoluble drug vectors.

Method: Three compounds were successfully through acylation, substitution reaction, reduction reaction and esterification. Their structures were verified by NMR analysis; and the critical micelle concentrations (CMC) of TEG-R1, TEG-R2, TEG-R3 were determined by pyrene fluorescence probe spectrometry.

Lectin-directed enzyme activated prodrug therapy (LEAPT): Synthesis and evaluation of rhamnose-capped prodrugs.

The lectin-directed enzyme activated prodrug therapy (LEAPT) bipartite drug delivery system utilizes glycosylated enzyme, localized according to its sugar pattern, and capped prodrugs released by that enzyme. In this way, the sugar coat of a synthetic enzyme determines the site of release of a given drug. Here, prodrugs of doxorubicin and 5-fluorouracil capped by the nonmammalian l-rhamnosyl sugar unit have been efficiently synthesized and evaluated for use in the LEAPT system.

[Synthesis of G3.5 dendrimer-2-aminoethyl ß-D-galactopyranoside conjugates and its specificity on hepatocyte targeting in vitro].

Objective: To prepare a valuable nanodevice targeting for hepatic parenchymal cells to improve the effects of drugs for treatment of hepatitis B and liver cancer.

Methods: Generation 3.5 dendrimer (G3.

Blood compatibility of polyamidoamine dendrimers and erythrocyte protection.

Dendrimers are global macromolecules with promising biomedical application. In order to investigate their blood compatibility, different generations of polyamidoamine (PAMAM) dendrimers terminated with different types of surface functional groups were incubated with red blood cells (RBC) for time course of haemolysis assay and RBC morphology observation. Cationic PAMAM dendrimers demonstrated obvious generation, concentration and time dependent haemolysis while anionic and neutral PAMAM dendrimers were much less hemolytic.

LEAPT: lectin-directed enzyme-activated prodrug therapy.

Targeted drug delivery to selected sites allows reduced toxicity, enhanced efficiency and interchangeable target potential [Langer, R. (2001) Science 293, 58-59 and Molema, G. & Meijer, D.

[Preparation of thrombus-targeted urokinase liposomes and its thrombolytic effect in model rats].

Aim: To prepare thrombus-targeted urokinase liposomes and observe its improved thrombolytic efficacy on thrombus model rats.

Methods: The ligand H-Arg-Gly-Asp-Ser-OH (RGDS) which has specific affinity to thrombus was synthesized by liquid phase method and anchored on the surface of liposomes by incorporating its conjugate with DSPE-PEG3,500-COOH into liposomal lipid bilayers, thus thrombus-targeted liposomes were produced. Urokinase (UK) liposomes were prepared at room temperature through method modification using hydrogenated soy phosphatidylcholine (HSPC); the in vivo thrombolysis of the obtained thrombus-targeted UK liposomes and its comparison with TBS (Tris-HCl buffered solution) control, free UK and UK liposomes were assessed on common carotid artery model rats.

[Study on the hepatocytic cell targetability of liposomes].

Aim: To target for hepatocytic cell, liposomes was modified by special ligand.

Methods: Sterically stabilized liposomes (SSL) was conjugated with asialofeticin (AF), the ligand of asialoglycoprotein receptor (ASGP-R) of hepatocyte. ASGP-R-BLM is the ASGP-R reconstructed on bilayer lipid membrane (BLM).

Studies on alginate-chitosan microcapsules and renal arterial embolization in rabbits.

Spherical and well-dispersed alginate-chitosan microcapsules, with a mean diameter of 77.28+/-0.93 microm (n=3), were prepared by the emulsification-gelation method.

Phospholipid deformable vesicles for buccal delivery of insulin.

To investigate the possibility of the enhancing effect of deformable vesicles on buccal delivery of insulin, two kinds of vesicles with and without the presence of sodium deoxycholate (deformable vesicles and conventional vesicles) were prepared by reverse phase evaporation methods. The liposomal entrapment efficiency was determined by column chromatography. The particle size and morphology of the vesicles were also evaluated.