乌鲁木齐雅玛里克山土壤动物群落结构及其多样性研究

为了查明不同海拔高度对土壤动物群落多样性及其时空动态的影响,对乌鲁木齐雅玛里克山6种不同海拔高度样带土壤动物群落进行了调查分析,以探讨雅玛里克山土壤动物群落结构与不同海拔高度之间的关系.结果表明,共获得大、中小型土壤动物7 375只,隶属于6门16纲35目,其中真螨目(52.28%)和弹尾目(15.61%)为优势类群,共占总捕获量的67.89%,而寄螨目(8.37%)、三肠目(7.78%)、膜翅目(2.74%)、茅线目(1.53%)、双翅目幼虫(1.48%)、垫刃目(1.27%)、鞘翅目(1.11%)及半翅目(1.07%)等8类为常见类群,占总捕获量的25.35%,其余的25类为稀有类群,占总捕获量的6.76%.在6种不同海拔样带土壤动物个体数和类群数之间存在显著差异(P<0.05),个体数顺序为:样带A>样带B>样带C>样带E>样带D>样带F,而类群数顺序为:样带A>样带B>样带C>样带D>样带E>样带F.3个不同季节有明显的差异(P<0.01),其个体数依次为秋>春>夏.在6种不同高度样带和不同生境土壤动物群落多样性指标之间存在差异(P<0.05).组间聚类和排序结果表明,将6种不同海拔高度生境分为山底生境型、山中生境型及山顶生境型等三大类型.     

Diagnostic of Biomphalaria snails and Schistosoma mansoni: DNA obtained from traces of shell organic materials

Freshwater snails belonging to the genus Biomphalaria act as intermediate hosts for the parasite trematode Schistosoma mansoni in Africa and in the neotropical region. Identification of such molluscs is carried out based on morphological characters and the presence of cercariae is verified through squeezing snails between two glass slides or by exposing them to artificial light. However, sometimes, the material collected includes molluscs with decomposed bodies or, yet, only empty shells, which precludes their identification and S. mansoni detection. Due to these difficulties, we have developed a methodology in which DNA may be extracted from traces of organic material from inside shells in order to identify molluscs through polymerase chain reaction and restriction fragment length polymorphism and to detect S. mansoni into these snails, by using low stringency polymerase chain reaction. Species-specific profiles obtained from B. glabrata, B. straminea, and B. tenagophila snails and their shells, maintained in laboratory for ten years, showed the same profiles. S. mansoni profiles showed to be present in shell specimens as far as the eighth week after being removed from aquarium.     

Vascular endothelial growth factor-induced secretion of fibronectin is ERK dependent

In severe asthma, cytokines and growth factors contribute to the proliferation of smooth muscle cells and blood vessels, and to the increased extracellular matrix deposition that constitutes the process of airway remodeling. Vascular endothelial growth factor (VEGF), which regulates vascular permeability and angiogenesis, also modulates the function of nonendothelial cell types. In this study, we demonstrate that VEGF induces fibronectin secretion by human airway smooth muscle (ASM) cells. In addition, stimulation of ASM with VEGF activates ERK, but not p38MAPK, and fibronectin secretion is ERK dependent. Both ERK activation and fibronectin secretion appear to be mediated through the VEGF receptor flt-1, as evidenced by the effects of the flt-1-specific ligand placenta growth factor. Finally, we demonstrate that ASM cells constitutively secrete VEGF, which is increased in response to PDGF, transforming growth factor-beta, IL-1beta, and PGE(2). We conclude that ASM-derived VEGF, through modulation of the extracellular matrix, may play an important role in airway remodeling seen in asthma.     

Induction of anti-melanoma CTL response using DC transfected with mutated mRNA encoding full-length Melan-A/MART-1 antigen with an A27L amino acid substitution

Modification of the parental immunodominant Melan-A/MART-1 peptide (MART-1(26-35)) by replacing the alanine with leucine (A27L) enhances its immunogenicity. Because of the reported advantages of RNA over peptides in DC vaccines, we sought to mutate the MART-1 gene to encode a full-length MART-1 antigen with an A27L amino acid substitution. Human DC were transfected with A27L-mutated MART-1 RNA (A27L RNA) or native MART-1 RNA, and then used to stimulate autologous T cells from a series of 8 HLA-A2+ volunteers. After three stimulations, all CTL induced with DC/A27L RNA exhibited more tetramer+ cells, and demonstrated stronger antigen-specific IFNgamma-secreting activity compared to CTL induced with DC/native RNA. A potent MART-1-specific, and predominantly class-I-restricted lysis was detected in most CTL induced with DC/A27L RNA, while native RNA-induced CTL showed minimal and non-specific lysis. HLA-A2+ DC and MART-1 negative/A2+ melanoma cells transfected with the A27L RNA were recognized and killed by MART-1-specific CTL, suggesting that these APC efficiently processed the A27L RNA and presented correct MART-1-specific epitope(s). In summary, introducing an A27L mutation into the MART-1 full-length mRNA sequence enhanced the immunogenicity of the encoded MART-1 Ag. The ease with which such a mutation can be made in RNA presents another potential advantage of using RNA for immunotherapy. Our results support considering this strategy for enhancing the immunogenicity of DC-based RNA vaccines.     

A neutral beta-D-glucan from dates of the date palm,Phoenix dactylifera L

Polysaccharides extracted from Libyan dates with hot water and 0.05 M NaOH were fractionated and purified by ion-exchange and gel-filtration chromatography. According to the methylation and hydrolysis analyses, the results indicate the D-glucan to be linear and to contain both (1-->3)- and (1-->4)-linkages. The anomeric NMR measurements confirm that the sugar residues are beta-glycosidically linked. This is the first report on the isolation of a neutral beta-D-glucan from dates.     

Surfactant protein A regulates surfactant phospholipid clearance after LPS-induced injury in vivo

Previous in vitro studies have suggested that surfactant protein A (SP-A) may play a role in pulmonary surfactant homeostasis by mediating surfactant secretion and clearance. However, mice made deficient in SP-A [SP-A (-/-) animals] have relatively normal levels of surfactant compared with wild-type SP-A (+/+) animals. We hypothesize that SP-A may play a role in surfactant homeostasis after acute lung injury. Bacterial lipopolysaccharide was instilled into the lungs of SP-A (-/-) mice and SP-A (+/+) mice to induce injury. Surfactant phospholipid levels were increased 1.6-fold in injured SP-A (-/-) animals, although injury did not alter [3H]choline or [14C]palmitate incorporation into dipalmitoylphosphatidylcholine (DPPC), suggesting no change in surfactant synthesis/secretion 12 h after injury. Clearance of [3H]DPPC from the lungs of injured SP-A (-/-) animals was decreased by approximately 40%. Instillation of 50 microg of exogenous SP-A rescued both the clearance defect and the increased phospholipid defect in injured SP-A (-/-) animals, suggesting that SP-A may play a role in regulating clearance of surfactant phospholipids after acute lung injury.     

Theoretical investigation of the triphosphate forms of azidothymidine and thymidine

In this paper we investigate (using AM1 semi-empirical as well as HF methods at the STO-3G, 3-21G, 6-31G, 6-31G* and 6-31+G** level) the conformations, geometrical parameters, Mulliken charges, and solvation effects of the triphosphate form of AZT (AZTTP), as well as the thymidine nucleotide (dTTP) structure. Our calculated geometrical parameters and Mulliken charges, with and without solvation effects, are correlated with recent experimental results.     

Role of the promyelocytic leukemia body in the dynamic interaction between the androgen receptor and steroid receptor coactivator-1 in living cells

The dynamic interaction between the androgen receptor (AR) and steroid receptor coactivator-1 (SRC-1) was explored in living cells expressing chimeric forms of the receptor and the coactivator containing two spectral variants of jellyfish fluorescent protein. Laser scanning confocal imaging of transfected cells expressing fluorescently labeled SRC-1 revealed that in an unsynchronized cell population, the coactivator is distributed in approximately 40% cells as nuclear bodies of 0.2-1.0 microm in diameter. Immunostaining of cyan fluorescent protein-labeled SRC-1 (CFP-SRC1)-expressing cells with antibody to promyelocytic leukemia (PML) protein showed significant overlap of the CFP fluorescence with the antibody stain. Cotransfection of cells with a plasmid expressing the CFP conjugate of Sp100 (another marker protein for the PML nuclear body) also showed colocalization of the yellow fluorescent protein (YFP)-SRC1 containing nuclear foci with the PML bodies in living cells. Analysis of the three-dimensional structure revealed that the PML bodies are round to elliptical in shape with multiple satellite bodies on their surface. Some of these satellite bodies contain the SRC-1. Activation and nuclear import of CFP-AR by the agonistic ligand 5alpha-dihydrotestosterone, but not by the antagonist casodex, transferred YFP-SRC1 from the PML bodies to an interlacing filamentous structure. In a single living cell, agonist-activated AR caused a time-dependent movement of YFP-SRC1 from the PML bodies to this filamentous structure. Additionally, coexpression of a constitutively active mutant of AR (AR-deltaligand binding domain) also displaced YFP-SRC1 from the PML bodies to this intranuclear filamentous structure. The fluorescence recovery after photobleaching approach was used to examine changes in the kinetics of movement of YFP-SRC1 during its mobilization from the PML bodies to the intranuclear filamentous structure by the agonist-activated AR. Results of the relative half-times (t(1/2)) of replacement of YFP-SRC1 within the photobleached region of a single PML body from its surrounding nuclear space supported the conclusion that SRC-1 is actively transported from the PML bodies to the intranuclear filamentous structure by the ligand-activated AR. This observation also suggests an interaction between AR and SRC-1 before its binding to the target gene. The PML bodies have been implicated as a cross-road for multiple regulatory pathways that control cell proliferation, cellular senescence, and apoptosis. Our present results along with other recent reports expand the role of this subnuclear structure to include the regulation of steroid hormone action.