Synthesis of caged 2,3,3a,7a-tetrahydro-3,6-methanobenzofuran-7(6H)-ones: Evaluating the minimum structure for apoptosis induction by gambogic acid

We have reported the discovery of gambogic acid (GA) as a potent apoptosis inducer and the identification of transferrin receptor as its molecular target. In order to understand the basic pharmacophore of GA for inducing apoptosis and to discover novel and simplified derivatives as potential anti-cancer agents, we explored the synthesis of caged 2,3,3a,7a-tetrahydro-3,6-methanobenzofuran-7(6H)-ones (4-oxatricyclo[4.3.1.0]decan-2-ones). Three types of 2,3,3a,7a-tetrahydro-3,6-methanobenzofuran-7(6H)-ones based on xanthone, 2-phenylchromene-4-one and benzophenone, were synthesized using a Claisen/Diels-Alder reaction cascade. All the reactions produced the targeted caged compound as well as its neo-isomer. The caged compounds based on xanthone and 2-phenylchromene-4-one were found to maintain the apoptosis inducing and cell growth inhibiting activity of GA, although with less potency. The caged compounds based on benzophenone were found to be inactive. Our study determined the minimum structure of GA for its apoptosis inducing activity, which could lead to the development of simple derivatives as potential anti-cancer drugs.     

Expression pattern and polymorphism of three microsatellite markers in the porcine CA3 gene

Carbonic anhydrase III (CA3) is an abundant muscle protein characteristic of adult type-1, slow-twitch, muscle fibres. In order to further understand the functions of the porcine CA3 protein in muscle, the temporal and spatial distributions of its gene product were analysed and the association between the presence of specific polymorphisms and carcass traits in the pig was also examined. Real-time PCR revealed that the CA3 mRNA expression showed no differences with age in skeletal muscles from Yorkshire pigs at postnatal day-1, month-2, and month-4. We provide the first evidence that CA3 is differentially expressed in the skeletal muscle of Yorkshire and Meishan pig breeds. In addition, the whole pig genomic DNA sequence of CA3 was investigated and shown to contain seven exons and six introns. Comparative sequencing of the gene from three pig breeds revealed the existence of microsatellite SJ160 in intron 5 and microsatellite SJ158 and a novel microsatellite marker that includes a tandem repeat of (TC)_n in intron 4. We also determined the allele number and frequencies of the three loci in seven pig breeds and found that they are low polymorphic microsatellite markers. Statistical analysis showed that the CA3 microsatellite polymorphism was associated with dressing percentage, internal fat rate, carcass length, rib number and backfat thickness in the pig.     

Threatened fishes of the world: <Emphasis Type="Italic">Hucho bleekeri</Emphasis> Kimura, 1934 (Salmonidae)

Conservation status, identification, distribution, habitat and ecology, reproduction, threats, conservation actions and recommendations of a critically endangered fish, Hucho bleekeri Kimura, which is endemic to China, was introduced.     

Soil-Water Threshold Range of Chemical Signals and Drought Tolerance Was Mediated by ROS Homeostasis in Winter Wheat During Progressive Soil Drying

The soil-water threshold range of chemical signals and reactive oxygen species (ROS) homeostasis could have a profound impact on drought tolerance in wheat. A pot experiment was used to investigate the homeostasis between ROS and antioxidant defense at five harvest dates, and its role in the correlation between soil-water threshold range of chemical signals and drought tolerance in three wheat (Triticum aestivum) cultivars during progressive soil drying. The cultivars were bred at different periods, cv. BM1 (old), cv. Xiaoyan6 (recent), and cv. Shan229 (modern). They were treated with progressive soil drying. Shoot biomass was affected by drought imposed by two water treatments (90% and 55% field water capacity). The modern wheat cultivar had a lower ROS content and higher ROS-scavenging antioxidant capacity with greater soil drying (68–25% soil water content) compared with the older cultivar. The modern cultivar also had excellent adaptation to drought, with a longer survival of 22.7 days and less reduction in shoot biomass of 20.9% due to early chemical signals and better balance between ROS production and antioxidants. The older cultivar had survival of 15.3 days and 37.3% reduction of shoot biomass. A wider soil-water threshold range of chemical signals was positively correlated with improved drought tolerance and better ROS homeostasis. These results suggest that ROS homeostasis acts as a regulator in relationships between the soil-water threshold range of chemical signals and drought tolerance.     

A proteomic study reveals the diversified distribution of plasma membrane-associated proteins in rat hepatocytes

To investigate the heterogeneous protein composition of highly polarized hepatocyte plasma membrane (PM), three PM-associated subfractions were obtained from freshly isolated rat hepatocytes using density gradient centrifugation. The origins of the three subfractions were determined by morphological analysis and western blotting. The proteins were subjected to either one-dimensional (1-D) SDS-PAGE or two-dimensional (2-D) benzyldimethyl-n-hexadecylammonium chloride (BAC)/SDS-PAGE before nano-Liquid Chromatography-Electrospray Ionization--tandem mass spectrometry analysis (LC-ESI-MS/MS). A total of 613 non-redundant proteins were identified, among which 371 (60.5%) proteins were classified as PM or membrane-associated proteins according to GO annotations and the literatures and 32.4% had transmembrane domains. PM proteins from microsomal portion possessed the highest percentage of transmembrane domain, about 46.5% of them containing at least one transmembrane domain. In addition to proteins known to be located at polarized liver PM regions, such as asialoglycoprotein receptor 2, desmoplakin and bile salt export pump, several proteins which had the potential to become novel subfraction-specific proteins were also identified, such as annexin a6, pannexin and radixin. Our analysis also evaluated the application of 1-D SDS-PAGE and 2-D 16-BAC/SDS-PAGE on the separation of integral membrane proteins.     

Chemistry and weak antimicrobial activities of phomopsins produced by mangrove endophytic fungus Phomopsis sp. ZSU-H76

Three metabolites named phomopsin A (1), B (2) and C (3), together with two known compounds cytosporone B (4) and C (5), were isolated from the mangrove endophytic fungus, Phomopsis sp. ZSU-H76 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly by 1D and 2D NMR spectroscopic techniques. The medium-sized cyclic phenol ether based on 1 or 2 is rare in natural products. In bioassays, compounds 1, 2, and 3 had no significant antibiotic activities, but compounds 4 and 5 inhibited two fungi Candida albicans and Fusarium oxysporum with an MIC ranging from 32 to 64 microg/ml.     

大鼠尾壳核头部生长抑素mRNA的区域性表达

目的　观察尾壳核 (CP)头部背内侧区、背外侧区、腹内侧区和腹外侧区生长抑素 (SOM )mRNA阳性神经元分布特点。方法　采用原位杂交组织化学方法。结果　CP头部不同区域SOMmRNA阳性神经元的密度存在差异 ,腹内侧区SOMmRNA阳性神经元的密度明显高于其他区 (P <0 0 1)。结论　CP头部不同区域的SOMmRNA阳性神经元密度存在差异 ,这可能是CP头部不同区域机能差异的形态学基础之一。     

大鼠隔区接受海马一氧化氮合酶(NOS)阳性神经元的投射

目的逆行追踪大鼠海马NOS阳性神经元向隔区的投射。方法用HRP逆行追踪与NADPH-d组化方法相结合进行研究。结果背、腹、后海马均有NOS阳性神经元投射至隔区各亚细胞群,后海马NOS阳性神经元向隔外侧核(sl)、隔三角核和隔伞核(ts,sf)的投射量,占后海马至隔外侧核、隔三角核和隔伞核投射量的80％左右。结论大鼠隔区接受海马NOS神经元的投射。     

单向放射免疫扩散法测定流感灭活疫苗血凝素含量的研究

为改进流感灭活疫苗血凝素含量的测定方法 ,将待测样品经去污剂处理后 ,用WHO标准品作对照进行免疫扩散测定 10个流感灭活疫苗样品血凝素含量。在血凝效价相同的情况下 ,疫苗中三价 (A1,A3,B)血凝素含量存在不同程度的差异。可见 ,单向放射免疫扩散法较血球凝集法更适用于流感灭活疫苗血凝素含量的测定。