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51.
Recombinant adeno-associated virus(rAAV) has proven to be a promising gene delivery vector for human gene therapy. However, its application has been limited by difficulty in obtaining enough quantities of high-titer vector stocks. In this paper, a novel and highly efficient production system for rAAV is described. A recombinant herpes simplex virus type 1(rHSV-1) designated HSV1-rc/△UL2, which expressed adeno-associated virus type2(AAV-2) Rep and Cap proteins, was constructed previously. The data confirmed that its functions were to support rAAV replication and packaging, and the generated rAAV was infectious. Meanwhile, an rAAV proviral cell line designated BHK/SG2, which carried the green fluorescent protein(GFP) gene expression cassette, was established by transfecting BHK-21 cells with rAAV vector plasmid pSNAV-2-GFP. Infecting BHK/SG2 with HSV1-rc/△UL2 at an MOI of 0.1 resulted in the optimal yields of rAAV, reaching 250 transducing unit(TU) or 4.28×104 particles per cell. Therefore, compared with the conventional transfection method, the yield of rAAV using this "one proviral cell line, one helper virus" strategy was increased by two orders of magnitude. Large-scale production of rAAV can be easily achieved using this strategy and might meet the demands for clinical trials of rAAV-mediated gene therapy.  相似文献   
52.
For over the past 20 years, a remarkable development in the study and search of natural products has been observed. This is linked to a new market trend towards ecology and also due to new regulations. This could be a rupture, but also a real booster for creativity. Usually, in the flavor and fragrance field, creativity was boosted by the arrival of new synthetic molecules. Naturals remained the traditional, century‐old products, protected by secrecy and specific know‐how from each company. Regulatory restrictions or eco‐friendly certification constraints like hexane‐free processes triggered an important brainstorming in the industry. As a result, we developed new eco‐friendly processes including supercritical CO2 extraction, allowing fresh plants to be used to obtain industrial flower extracts (Jasmine Grandiflorum, Jasmine Sambac, Orange blossom). These extracts are analyzed by GC, GC/MS, GC? O, and HPTLC techniques. New or unusual raw materials can also be explored, but the resulting extracts have to be tested for safety reasons. Some examples are described.  相似文献   
53.
Geng Y  Wang Y  Yang K  Wang S  Zeng H  Baumann F  Kuehn P  Scholten T  He JS 《PloS one》2012,7(4):e34968
The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC) stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs) studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows) along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1) belowground biomass (BGB) is most closely related to spatial variation in Rs due to high root biomass density, and (2) soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 μmol CO(2) m(-2) s(-1), ranging from 0.39 to 12.88 μmol CO(2) m(-2) s(-1), with average daily mean Rs of 2.01 and 5.49 μmol CO(2) m(-2) s(-1) for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB), SOC, soil moisture (SM), and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80%) of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82%) of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.  相似文献   
54.
The aim of the study was to investigate the metabolism of 4‐fluoro‐N‐(1‐{2‐[(propan‐2‐yl)phenoxy]ethyl}‐8‐azabicyclo[3.2.1]octan‐3‐yl)‐benzenesulfonamide (PZ‐1150), a novel 5‐HT7 receptor antagonist with antidepressant‐like and anxiolytic properties, by the following three ways: in vitro with microsomes; in vitro employing Cunninghamella echinulata, and in silico using MetaSite. Biotransformation of PZ‐1150 with microsomes resulted in five metabolites, while transformation with C. echinulata afforded two metabolites. In both models, the predominant metabolite occurred due to hydroxylation of benzene ring. In silico data coincide with in vitro experiments, as three MetaSite metabolites matched compounds identified in microsomal samples. In human liver microsomes PZ‐1150 exhibited in vitro half‐life of 64 min, with microsomal intrinsic clearance of 54.1 μL/min/mg and intrinsic clearance of 48.7 mL/min/kg. Therefore, PZ‐1150 is predicted to be a high‐clearance agent. The study demonstrated the applicability of using microsomal model coupled with microbial model to elucidate the metabolic pathways of compounds and comparison with in silico metabolite predictions.  相似文献   
55.
Habitat fragmentation has often been implicated in the decline of many species. For habitat specialists and/or sedentary species, loss of habitat can result in population isolation and lead to negative genetic effects. However, factors other than fragmentation can often be important and also need to be considered when assessing the genetic structure of a species. We genotyped individuals from 13 populations of the cooperatively breeding Brown‐headed Nuthatch Sitta pusilla in Florida to test three alternative hypotheses regarding the effects that habitat fragmentation might have on genetic structure. A map of potential habitat developed from recent satellite imagery suggested that Brown‐headed Nuthatch populations in southern Florida occupied smaller and more isolated habitat patches (i.e. were more fragmented) than populations in northern Florida. We also genotyped individuals from a small, isolated Brown‐headed Nuthatch population on Grand Bahama Island. We found that populations associated with more fragmented habitat in southern Florida had lower allelic richness than populations in northern Florida (P = 0.02), although there were no differences in heterozygosity. Although pairwise estimates of FST were low overall, values among southern populations were generally higher than northern populations. Population assignment tests identified K = 3 clusters corresponding to a northern cluster, a southern cluster and a unique population in southeast Florida; using sampling localities as prior information revealed K = 7 clusters, with greater structure only among southern Florida populations. The Bahamas population showed moderate to high differentiation compared with Florida populations. Overall, our results suggest that fragmentation could affect gene flow in Brown‐headed Nuthatch populations and is likely to become more pronounced over time.  相似文献   
56.
裴俊峰  冯慧 《动物学杂志》2024,59(1):103-114
2011年4和8月及2014年4月在陕西省宝鸡市太白县分别采集到2只、1只和1只共4只蝙蝠个体,标本保存于陕西省动物研究所标本馆(标本编号为TB0001、TB0002、TB0017和TB0042)。其主要形态特征为:体型小,头体长34.59 ~ 43.86 mm(n = 4);耳较小,黑色;耳前缘近凸圆,耳后缘在基部有一浅的缺刻;耳屏细长,约为耳长的一半;后足不及胫长的一半;背部毛基黑色,毛尖为赤褐色;腹部毛基为黑色,毛尖为灰褐色;翼膜起始于后足外趾的基部。以上特征均与喜山鼠耳蝠moupinensis亚种(Myotis muricola moupinensis)相符。结合线粒体Cyt b基因序列,构建其系统发生关系,与基因库中宽吻蝠属未定种(Submyotodon sp.)序列聚为较高支持度的一支。综合形态与系统发育证据,参考目前最新的中国兽类物种分类和分布信息,将采集到的标本初步鉴定为喜山鼠耳蝠moupinensis亚种,此次发现是陕西省境内该物种的首次记录,拓展了对其在我国分布范围的认识。  相似文献   
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59.
Liu Z  Ng EK  Liang NC  Deng YF  Leung BC  Chen GG 《FEBS letters》2005,579(6):1477-1487
In this study, we demonstrated that Ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) had stronger cytotoxicity against MKN-45, a gastric cancer cell line bearing wild-type p53 than MKN-28, another gastric cancer cell line containing missense mutation in p53. The rapid increase of ROS level was involved in the mechanism of cytotoxicity. Classical features of apoptosis induced by 5F were observed in MKN-45 cells only or more significant in MKN-45 cells than MKN-28 cells. Translocation of Bax from cytosol to mitochondria, reduction of delta psi m and DNA fragmentation were induced by 5F in the p53-dependent manner. We conclude that the expression of Bax and its downstream molecules requires the presentation of a wild-type p53 in the cells treated by 5F.  相似文献   
60.
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