人为影响下古尔班通古特沙漠小尺度生态环境变化

随着沙漠中油气资源勘探开发、公路建设和重大工程相继实施 ,对生态环境的人为影响日益加深。本文以重大工程实验点为例 ,通过研究对比工程影响区内人工沙垄和自然沙垄的砂质新成土理化性状和植被群落特征 ,指出了沙漠生态环境在人为干扰下发生的一系列变化 ,以及受损生态环境在人们采取积极补救措施的情况下所具有的自然修复能力     

樟子松在西北干旱沙区的光合日变化特征

在甘肃省民勤治沙站 ,用 Li- 62 0 0便携式光合仪分别测定人工栽植的 4龄、9龄和 2 0龄樟子松的净光合速率日进程 ,其结果表明 :在干旱沙区 ,9龄以上樟子松的光合速率在午前随光强和气温而上升 ,午后下降。其 4龄、9龄和 2 0龄樟子松的最大净光合速率分别为 8.7μmol· m- 2 · s- 1、62 .3μmol· m- 2 · s- 1、1 9.7μmol· m- 2 · s- 1。     

Analysis of gene expression profile of multidrug resistant MCF/DOX cell line after benflumetol derivative LY980503 treatment

AIM:To investigate the effect of LY980503(a benflumetol derivative)on multidrug resistance of tumor cell line using DNA microarray.METHODS:Total RNA was extracted from multidrug resistant MCF/DOX cell line. cDNA microarray containing 320 cDNAs was used to detect the gene expression profile.RESULTS:9 down-regulated genes and 1 up-regulated gene were identified after multidrug resistant MCF/DOX cells were treated with LY980503.CONCLUSION:LY980503 can effectively reverse the resistance of MCF/DOX to DOX in vitro by adjusting the expression of multi-genes.     

Antisense drug targeting with VEGF mRNA designed by computer aid and inhibitory effects on K562 cell line in vitro

AIM:The effective antisense sequences targeted VEGF mRNA with computer software would be screened and designed, and effect of them on growth K562 cells and protein expression of VEGF were studied with experiments.METHODS:Seven antisense sequences were selected and synthesized, which consisted of 18-20 deoxynucleotide acid and were modified with phosphorothioate, according to principle of low free energy of overall △G₃₇ Overall. Cell growth was assayed by trypan blue dye exclusion assay and level of VEGF protien in the media was determined by ELISA.RESULTS:Six of seven sequences were capable of inhibing growth of K562 cells and downregulating the VEGF protein expression significantly, compared with Scrambed control group. It was found that there was a close correlation between low level of overall △G₃₇ and antisense effectiveness (r=0.887,P<0.01).CONCLUSION:VEGF mRNA antisense oliogdeoxynucleotides, which were designed by computer software of RNAstructure, were able to inhibit growth of K562 and its protein expression. The VEGF mRNA may be new target attached by drugs. At same time, the computer aided design is useful methods to obtain the effective antisense.     

Effect of cyclophosphamide on proliferation and apoptosis of rat mesangial cells in vitro

AIM:To investigate the effect of cyclophosphamide(CTX) on proliferation and apoptosis of mesangial cells(GMC) of rat in vitro. METHODS:GMC proliferat ion was detected by MTT method,GMC apoptosis was examined by inverted microscopy for phase-contract and fluoroscopy and flow cytometry analysis.The levels of Fas and Bcl-2 were also detected by immunohistology. RESULTS:The proliferation of GMC were inhibited by CTX, methylprednisolone(MP), low molecular weight heparin(LMWH). Apoptosis of GMC was induced by CTX, the apoptosis rate of GMC was 8.2%, and the Fas level was increased. CONCLUSION:CTX could inhibit proliferation and induce apoptosis of GMC possibly by enhancing the Fas level.     

Effects of the juice of Fructus Hippophae (JFH) on thrombocytopenia induced by cyclophosphamide in rats

AIM:To investigate the effects of the juice of fructus hippophae(JFH) on thrombocytopenia in rats.METHODS:Forty-eight wistar rats were divided into control group, model group, Yixuesheng-Jiaonang (YSJN) group and JFH group. Rats were injected intraperitoneally with cyclophosphamide (CTX, 30 mg/kg) or saline once a day for 3 days. And then, Saline, YSJN or JFH was administered (ig) once a day for 11 days. On the second, fouth, sixth and eighth day, the thrombocyte were counted, the mean platelet volume (MPV) and PDW were examined. On the eighth day, the cAMP, cGMP in platelets and platelet aggregation function were also examined.RESULTS:JFH could shorten the time of blood coagulation, increase the count of platelet, and enhance the platelet aggregation function. The experiment also showed that the JFH could decrease cGMP content in platelet.CONCLUSION:JFH could enhance blood coagulation and quality of platelet and prevent thrombocytopenia induced by cyclophosphamide in rats.     

Bcl-2 antisense oligodeoxynucleotide increases the sensitivity of HL60 and K562 cells to daunorubicin

AIM:To investigate whether the bcl-2 antisense oligonucleotide increases the sensitivity of HL60 and K562 cell lines to daunorubicin.METHODS:IC50 for HL60 and K562 was determined with MTT method, the expression levels of Bcl-2 protein were assayed by immunofluorescence using fluoresce isothiocyanate labeling. In addition, apoptosis was detected by morphological observation and flow cytometric analysis of DNA fragmentation.RESULTS:It was found that the two oligonucleotides directed against the coding region and the translation initiation of bcl-2 mRNA, combined respectively with daunorubicin, inhibited expression of bcl-2 protein, increased apoptosis in HL60 and K562 cells, and decreased IC50 of daunorubicin significantly (P＜0.05). Compared to the antisense oligonucleotide directed against the translation initiation of bcl-2 mRNA, the antisense oligonucleotide directed against the coding region showed stronger effects in the aspects of increasing the sensitivity of HL60 cells to daunorubicin (P＜0.05).CONCLUSIONS:These two antisense sequences in the translation initiation and the coding region of bcl-2 mRNA increased the sensitivity of HL60 and K562 cell lines to daunorubicin in a sequence-specific manner.     

Effects of Sini decoction on atherosclerosis and ceramide content of aorta in rabbits

AIM:To observe the effects of Sini decoction on atherosclerosis(AS) and ceramide content of aorta in rabbits. METHODS:28 rabbits were randomly divided into three groups. Control group was fed with a normal diet; High cholesterol group was fed 1% cholesterol and 5% fat diet; Sini decotion+ high cholesterol group was fed 1% cholesterol and 5% fat diet plus Sini decotion (4.2 g·kg^-1·d^-1). At the end of study, the plaque area were measured, the atorta ceramide and cell apoptosis were also detected. RESULTS:Sini decotion diminished lipid plaque area on the aortic endothelium, reduced the levels of aorta ceramide and the apoptosis index. CONCLUSION:Sini decoction has an inhibitory effect on AS, the mechanism may be that Sini decotion reduces concentration of ceramide in aorta.     

Expression of peroxisome proliferator-activated receptor α in rat fatty liver

AIM:To investigate the role of expression of peroxisome proliferator-activated receptor α(PPAR α) in pathogenesis of rat fatty liver.METHODS:The rats were treated with a low dose of carbon terachloride (CCl₄) and fed a high fat diet to produce fatty liver. We determined the concentrations of triglyceride (TG), total cholesterol (TC), free fatty acid (FFA) in liver and the alanine aminotransferase (ALT) activity, tumor necrosis factor-α (TNF-α), FFA in serum and the degree of hepatocytic steatosis. Total RNA of liver was extracted, and the expression of PPAR α were analyzed by semi-quantitative RT-PCR method.RESULTS:In model group, the hepatocytic PPAR α mRNA expression decreased to 0.41±0.28, compared to 1.41±0.29 in the control group (P＜0.01). The contents of TG, TC, FFA in model rat liver were (1.88±0.20) mmol·L^-1, (11.03±1.12) mmol·L^-1 and (1 260.38±151.27) μmol·L^-1, respectively, compared to (0.53±0.10) mmol·L^-1, (1.25±0.25) mmol·L^-1 and (334.30±27.09) μmol·L^-1 in the control group (P＜0.01). The activity of ALT, concentrations of TNF-α and FFA in serum were also increased remarkably in model group.CONCLUSION:Oxidation of fatty acid and utilization of lipids in liver are affected by reducing the expression of PPAR α, which result lipid accumulation in liver.     

Effects of TGF-β1 and TNF-α antisense PS-ODNS on ex vivo expansion of hematopoietic stem/progenitor cells(HSPC)

AIM:To study the effect of TGF-β₁ and TNF-α antisense PS-ODNS on ex vivo expansion of hematopoietic stem/progenitor cells (HSPC). METHODS:CD₃₄⁺cells were purified from fresh umbilical cord blood by immunomagnetic beads, and mononuclear cells were purified from bone marrow by Ficoll-hypaque. The effects of TGF-β₁ and /or TNF-α antisense PS-ODNS on ex vivo expansion of CD₃₄⁺ cells、CFU-GEMM、CFU-GM、CFU-E and BFU-E were detected by using liquid and semi-solid culture systems.RESULTS:TGF-β₁ antisense PS-ODNS cooperated with cytokines increased the number of CD₃₄⁺ cells, CFU-GEMM, CFU-GM, CFU-E and BFU-E, which was as 4, 2.6, 2.7, 1.8, 2.1 times as that of the control (the cytokines combination), respectively. TNF-α antisense PS-ODNS cooperated with cytokines respectively increased the number of CD₃₄⁺ cells, CFU-GEMM, CFU-GM, CFU-E and BFU-E by 4, 2.9, 2.6, 1.7, 1.8 times as that of the control. The above two antisense PS-ODNS cooperated with cytokines could respectively increased the number of CD₃₄⁺ cells, CFU-GEMM, CFU-GM, CFU-E and BFU-E by 5.3, 2.1, 2.7, 1.9, 1.8 times as that of the control.CONCLUSION:Inhibition of endogenous TGF-β₁ and TNF-α by antisense PS-ODNS will be one of the effective methods to expand HSPC ex vivo.