藤茶保健含片的研制

以藤茶浓缩汁、麦芽糖醇、山梨糖醇和低聚异麦芽糖为主要原料,经混合、造粒、干燥、压片等工序,制成了低热量、具有保健功能的藤茶含片.     

Long-Term Ecosystem Effects of Sand-Binding Vegetation in the Tengger Desert, Northern China

The planting of sand‐binding vegetation in the Shapotou region at the southeastern edge of the Tengger Desert began in 1956. Over the past 46 years, it has not only insured the smooth operation of the Baotou–Lanzhou railway in the sand dune section but has also played an important role in the restoration of the local eco‐environment; therefore, it is viewed as a successful model for desertification control and ecological restoration along the transport line in the arid desert region of China. Long‐term monitoring and focused research show that within 4–5 years of establishment of sand‐binding vegetation, the physical surface structure of the sand dunes stabilized, and inorganic soil crusts formed by atmospheric dust gradually turned into microbiotic crusts. Among the organisms comprising these crusts are cryptogams such as desert algae and mosses. In the 46 years since establishing sand‐binding vegetation, some 24 algal species occurred in the crusts. However, only five moss species were identified, which was fewer than the species number in the crust of naturally fixed sand dunes. Other results of the planting were that near‐surface wind velocity in the 46‐year‐old vegetation area was reduced by 54.2% compared with that in the moving sand area; soil organic matter increased from 0.06% in moving sand dunes to 1.34% in the 46‐year‐old vegetation area; the main nutrients N, P, K, etc., in the desert ecosystem increased; soil physicochemical properties improved; and soil‐forming processes occurred in the dune surface layer. Overall, establishment of sand‐binding vegetation significantly impacted soil water cycles, creating favorable conditions for colonization by many herbaceous species. These herbaceous species, in turn, facilitated the colonization and persistence of birds, insects, soil animals, and desert animals. Forty‐six years later, some 28 bird species and 50 insect species were identified in the vegetated dune field. Thus, establishment of a relatively simple community of sand‐binding species led to the transformation of the relatively barren dune environment into a desert ecosystem with complex structure, composition, and function. This restoration effort shows the potential for short‐term manipulation of environmental variables (i.e., plant cover via artificial vegetation establishment) to begin the long‐term process of ecological restoration, particularly in arid climates, and demonstrates several techniques that can be used to scientifically monitor progress in large‐scale restoration projects.     

Cloning and characterization of an mRNA encoding a novel G protein alpha-subunit abundant in mantle and gill of pearl oyster Pinctada fucata

Nacre formation is an ideal model to study biomineralization processes. Although much has been done about biomineralization mechanism of nacre, little is known as to how cellular signaling regulates this process. We are interested in whether G protein signaling plays a role in mineralization. Degenerate primers against conserved amino acid regions of G proteins were employed to amplify cDNA from the pearl oyster Pinctada fucata. As a result, the cDNA encoding a novel G(s)alpha (pfG(s)alpha) from the pearl oyster was isolated. The G(s)alpha cDNA encodes a polypeptide of 377 amino acid residues, which shares high similarity to the octopus (Octopus vulgaris) G(s)alpha. The well-conserved A, C, G (switch I), switch II functional domains and the carboxyl terminus that is a critical site for interaction with receptors are completely identical to those from other mollusks. However, pfG(s)alpha has a unique amino acid sequence, which encodes switch III and interaction sites of adenylyl cyclase respectively. In situ hybridization and Northern blotting analysis revealed that the oyster G(s)alpha mRNA is widely expressed in a variety of tissues, with highest levels in the outer fold of mantle and epithelia of gill, the regions essential for biomineralization. We also show that overexpression of the pfG(s)alpha in mammalian MC3T3-E1 cells resulted in increased cAMP levels. Mutant pfG(s)alpha that has impaired CTX substrate diminished its ability to induce cAMP production. Furthermore, the alkaline phosphatase (ALP) activity, an indicator for mineralization, is induced by the G(s)alpha in MC3T3-E1 cells. These results indicated that G(s)alpha may be involved in regulation of physiological function, particularly in biological biomineralization.     

复方羚羊角注射液的抗病毒活性研究

我们用细胞培养法对大青叶、板兰根、羚羊角及复方羚羊角等注射液进行了抗病毒活性的实验研究。结果复方制剂优于单方,预防用药方式的效果最好,抑制病毒对数为3.25±0.45,属中等有效;治疗用药方式居中,抑药毒对数为2.38±0.96;同时用药方式接近无效,抑病毒对数为1.50±0.82。     

用彗星实验技术分析MTX对小鼠细胞DNA的损伤作用

MTX是一种抗叶酸药物 ,作用于增殖细胞 ,为了解其作用机制和探测其遗传毒性靶器官 ,以小鼠为研究对象 ,用彗星实验技术检测了MTX腹腔注射染毒后对脾、骨髓、胸腺、和外周血淋巴细胞的DNA损伤作用及其与MTX剂量间的相关。 1.2 5～ 5mg/kgMTX可诱发小鼠体内 4种细胞的DNA单链断裂 ,核DNA损伤程度与用药剂量呈正相关。不同种类细胞对MTX的易感性不同 ,脾、骨髓、胸腺、外周血淋巴细胞可能是MTX的遗传毒性靶细胞。外周血淋巴细胞在SCGE分析中的拖尾现象可作为用药后组织器官对药物敏感性反映的生物标志     

Role of the fourth intracellular loop of D1-like dopaminergic receptors in conferring subtype-specific signaling properties

We investigate whether the fourth intracellular loop (IL4) of D1 and D5 dopaminergic receptors (D1R, D5R) confers D1-like subtype-specific signaling properties. Using chimeric receptors (D1R-IL4B and D5R-IL4A), we show that swapping of IL4 leads to a switch in dopamine affinity and constitutive activity of D1R and D5R. Dopamine potency was reduced for both chimeras in comparison with wild-type receptors. Moreover, dopamine-mediated maximal activation was drastically increased in cells expressing D1R-IL4B when compared with those harboring D5R-IL4A or wild-type receptors. In conclusion, IL4 plays a pivotal role in imparting subtype-specific ligand binding and activation properties to highly homologous seven-transmembrane receptors.     

Locked nucleic acid containing antisense oligonucleotides enhance inhibition of HIV-1 genome dimerization and inhibit virus replication

We have evaluated antisense design and efficacy of locked nucleic acid (LNA) and DNA oligonucleotide (ON) mix-mers targeting the conserved HIV-1 dimerization initiation site (DIS). LNA is a high affinity nucleotide analog, nuclease resistant and elicits minimal toxicity. We show that inclusion of LNA bases in antisense ONs augments the interference of HIV-1 genome dimerization. We also demonstrate the concomitant RNase H activation by six consecutive DNA bases in an LNA/DNA mix-mer. We show ON uptake via receptor-mediated transfection of a human T-cell line in which the mix-mers subsequently inhibit replication of a clinical HIV-1 isolate. Thus, the technique of LNA/DNA mix-mer antisense ONs targeting the conserved HIV-1 DIS region may provide a strategy to prevent HIV-1 assembly in the clinic.     

Structures of human MAP kinase kinase 1 (MEK1) and MEK2 describe novel noncompetitive kinase inhibition

MEK1 and MEK2 are closely related, dual-specificity tyrosine/threonine protein kinases found in the Ras/Raf/MEK/ERK mitogen-activated protein kinase (MAPK) signaling pathway. Approximately 30% of all human cancers have a constitutively activated MAPK pathway, and constitutive activation of MEK1 results in cellular transformation. Here we present the X-ray structures of human MEK1 and MEK2, each determined as a ternary complex with MgATP and an inhibitor to a resolution of 2.4 A and 3.2 A, respectively. The structures reveal that MEK1 and MEK2 each have a unique inhibitor-binding pocket adjacent to the MgATP-binding site. The presence of the potent inhibitor induces several conformational changes in the unphosphorylated MEK1 and MEK2 enzymes that lock them into a closed but catalytically inactive species. Thus, the structures reported here reveal a novel, noncompetitive mechanism for protein kinase inhibition.     

Hypoxia-induced nucleophosmin protects cell death through inhibition of p53

Nucleophosmin (NPM) is a multifunctional protein that is overexpressed in actively proliferating cells and cancer cells. Here we report that this proliferation-promoting protein is strongly induced in response to hypoxia in human normal and cancer cells. Up-regulation of NPM is hypoxia-inducible factor-1 (HIF-1)-dependent. The NPM promoter encodes a functional HIF-1-responsive element that can be activated by hypoxia or forced expression of HIF-1alpha. Suppression of NPM expression by small interfering RNA targeting NPM increases hypoxia-induced apoptosis, whereas overexpression of NPM protects against hypoxic cell death of wild-type but not p53-null cells. Moreover, NPM inhibits hypoxia-induced p53 phosphorylation at Ser-15 and interacts with p53 in hypoxic cells. Thus, this study not only demonstrates hypoxia regulation of a proliferation-promoting protein but also suggests that hypoxia-driven cancer progression may require increased expression of NPM to suppress p53 activation and maintain cell survival.