The free radicals are some substances which have important influence on the human health. They both have salutary and harmful aspects to the human health. The role of free radicals in the lung cancer induced by physical and chemical factors such as smoking, occupational dust particles, metal ions, quartz, asbestos were briefly discussed in this article.

Mesenchymal stem cells express major histocompability complex (MHC)Ⅰin low levels, but do not express MHC Ⅱ, so it has a low immunogenicity. It can block maturity of dendritic cells, depress immune response of T lymphocytes, and also mediate immune suppression by secreting several soluble cytokines. In light of these characters, mesenchymal stem cell can avoid allograft rejection in human and animal transplantation. It has been reported previously that human mesenchymal stem cells cultivated in growing rodent embryos can grew out of new kidney and ureter. Furthermore, urea nitrogen and creatinine levels were significantly higher in liquid collected from the new ureter compared with the animal serum levels, which suggested that the new kidney had generated urine. This native kidney has low immunogenicity, little side-effect after transplantation, extensive sources, so it may have wide space in self-kidney transplantation.

OBJECTIVE: To study the antiatherosclerotic effect of Jiawei zexie tang(GWZXT) and the possible mechanisms.METHODS: 48 healthy male SD rats were randomized to 5 groups,i.e normal control,model group,simvastatin group,and high dosage and low dosage GWZXT groups.Artherosclerosis rat model was established by feeding high fat forage and the corresponding drugs were administered intragastrically.Changes in serum levels of APoAⅠ,ApoB,Zn,Cu,Ca and Mg and the ultrastructure were detected.RESULTS: In high dosage GWZXT-treated group compared with model group,the Zn,Ca and ApoB levels decreased significantly(P

Bone marrow-derived mesenchymal stem cells (MSCs) have potentials of proliferation, multilineage differentiation and homing to injured tissue and organs. Therefore, many researchers consider them as seed cells and attempt to use them to repair injured tissues and organs. In the allo- even xero-transplantation of these seed cells, graft rejection is an important problem. A large amount of data show that MSCs have specific immune characteristics; they block dendritic cell maturation, decrease immune response of T cells, do not express class Ⅱ major histocompatibility complex molecules, and mediate immunosuppression by secreting some dissoluble factors. The specific low immunogenicity of MSCs could avoid rejection in xero-trensplantation for human and animals in vivo, showing advantages in treatment. Therefore, they are promising to be used as seed cells for kidney construction.

Radish phospholipid hydroperoxide glutathione peroxidase (RsPHGPx) was identified as a mitochondrion-targeting PHGPx in previous work. To determine its cleavage site of the targeting peptide, the immunoaffinity chromatography (IAC) purification approach was carried out to isolate the native RsPHGPx protein.Polyclonal antibodies directed against recombinant RsPHGPx were raised in rabbit. Monospecific anti-RsPHGPx antibodies were isolated by means of affinity chromatography using the recombinant RsPHGPx as affinity ligand, and employed in assembling an IAC column. A single-step, highly specific and easy-to-use protocol was developed for purification of the active RsPHGPx protein through the assembled IAC column. Using this approach, a specific protein of the expected molecular size was obtained from the mitochondrial fraction of radish seedlings. Western blot analysis showed that it could be specifically recognized by anti-RsPHGPx antibodies, and an enzyme activity assay indicated that it exhibited significant PHGPx activity, suggesting that the purified protein should be the desired native RsPHGPx. These results will lead to clarification of the targeting peptide and the active mature protein of RsPHGPx and will be helpful to further probe the intracellular localization mechanism and biological fun ction of this plant PHGPx.

A novel radish RsPHGPx cDNA, which encodes a functional phospholipid hydroperoxide glutathioneperoxidase (PHGPx) protein, was identified in the previous work. In the study genomic organization and the upstream regulatory sequence analysis of this gene was presented. Southern blot analysis showed that RsPHGPx gene existed in radish genome in manner of single copy. Moreover, a 3.3 kb genomic DNA fragment of RsPHGPx gene was isolated by combination of common PCR and genome-walking method. Sequence analysis on this genomic fragment demonstrated that RsPHGPx gene consists of seven exons separated by six introns, and suggested that a short 5'-flanking sequence immediately before the exon 1 should be the putative RsPHGPx promoter region, which is proceeded by the upstream neighboring biotin synthase gene. Cis-acting elements search showed that the putative promoter contains elements responsive to hormones (eg. E-Box and W-Box), abiotic stresses (eg. MYB and MYC binding sites), and light (Box Ⅱ and Ⅰ-Box), etc. Northern blot analysis indicated that the expression of RsPHGPx was subjected to up-regulation of chilling and down-regulation of ABA and successive illumination (in etiolated seedlings), implying the regulatory roles of some predicted elements. However the up-regulation effect of herbicide paraquat, which can induce oxidative stress, suggested the presence of some unknown elements in the promoter region. This is the first report on gene structure and upstream regulatory sequence analysis in reported plant PHGPx genes, which will be a prerequisite to understand regulatory mechanism of PHGPx gene expression in plants.

Cotton (Gossypium hirsutum) is one of the most important economic crops in the world. Its growth and productivity were affected by environment stresses such as drought, cold and high salinity. Thus, the enhanced stress tolerance in this plant is of great importance. As the dehydration responsive element (DRE) binding protein (DBP) plays an important role in the regulation of plant resistance to environmental stresses and is quite useful for generating transgenic plants tolerant to these stresses, isolation and functional analysis of DBPs in cotton are important to cotton production. In the previous work, a DBP gene from cotton, named as GhDBP1, was isolated and its expression patterns in cotton plants was demonstrated at the transcriptional level. Here, the expression,purification and DNA binding activity of GhDBP1 were reported. The entire coding region of the GhDBP1 gene was inserted into an expression vector, pET28a, and transformed into Escherichia coli BL21 (DE3). The fusion protein was successfully expressed under IPTG induction and the purified recombinant protein was obtained by Ni-NTA affinity chromatography. Non-radioactive electrophoretic mobility shift assay revealed that the purified GhDBP1 protein was able to form a specific complex with the previously characterized DRE element. In addition, the computer modeling of the DNA-binding domain of GhDBP1 were performed using SWISS-MODEL software. The main-chain structures and the folding patterns of the DNA-binding domain of GhDBP1 were similar to the known structure of the DNA-binding domain of the Arabidopsis thaliana GCC box-binding protein AtERF1. These results indicate that GhDBP1 is a DRE-binding transcription factor and might use the structure similar to that of AtERF1 to interact with DRE sequence.

Proteins arc the major molecules performing life activities, and their spatial and temporal expression profiles in organisms are very important for understanding their accurate functions. Phospholipid hydroperoxide glutathione pcroxidase (PHGPx) is a unique antioxidant enzyme that directly reduces lipid hydroperoxides in biomembranes and plays a vital role in defense against mernhrane peroxidation damage. The protein expression profiles of rice PHGPx (OsPHGPx) were investigated in different rice tissues and under various stress treatments by using Western blot analysis. The results showed that in mature rice plants, OsPHGPx was mainly distributed in leaves, especially flag leaves, and in rice seedlings, OsPHGPx was detected in shoots and leaves. Moreover, OsPHGPx expression in rice seedlings could be markedly induced by H2O2 and NaCI, but weakly influenced by several plant hormones. Time- and dose-dependent effects were observed in both H2O2 and NaCI treatments, and the strongest induction was observed when rice seedlings were treated with 0.5 mmol/L H2O2 for 12 h or 500 mmol/L NaCI for 24 h. Additionally, dimethylthiourea, a H2O2 trap, inhibited H2O2-enhanced expression of OsPHGPx, but did not impair the enhanced effect of NaCI, implying that NaCl-induced OsPHGPx expression was not mediated by H2O2. These results will contribute greatly to further study the exact physiological function of OsPHGPx in rice.

GDP-mannose-3', 5' -epimerase (GME), which converts GDP-mannose into GDP-L-galactose, is essential for the biosynthesis of L-ascorbic acid in higher plants. The molecular characterization of two GME genes from rice has been reported. Firstly,both cDNAs were isolated from the rice mature leaves using RT-PCR technique. By comparing their sequences with homologues from other plants, it was found that GME genes were highly conserved among plant species, though phylogenetic study showed that all known GMEs could be divided into two distinct groups corresponding to monocots and dicots. Secondly, the genomic organization of rice OsGME genes was investigated, and a similarity of splice patterns was revealed. Finally, the expression patterns of the two cDNAs have been studied in various tissues and under different stress conditions by semiquantitative RT-PCR assay. The results showed that the OsGME1 transcript was up-regulated in response to cold stress, and gibberellin might regulate L-ascorbic acid levels by affecting transcription of both OsGME genes.

Background and purpose:Cancer microenvironment has become a hot topic of cancer research. It is important in the initiation of colorectal cancer. This study aimed to discuss the correlation between the characteristics of tissue culturein vitro and different cell types in cancer microenvironment.Methods:Samples were collected at different distances from the colorectal cancer lesions, which were named as positions 1, 2 and 3 from distal to proximal. Tissues were cut into 1-2 mm3 forin vitro culturing. HE staining was used to observe the structure of crypts. Immunohistochemistry was used to detect the expressions of Cyclin D1 (CD1), CD133, cytokeratin18 (CK18), vimentin and α-smooth muscle actin (α-SMA).Results:Position 3 grew faster than position 2 and position 1. As getting closer to the colorectal cancer lesions, expressions of CD1, CD133, vimentin and α-SMA were increased while expression of CK18 was decreased.Conclusion:The tissue structure and the expression of different cell types in cancer microenvironment changed more seriously as get-ting closer to the colorectal cancer lesions. This indicated that the change of cancer microenvironment may contribute to the initiation of colorectal cancer.