Synergetic inhibition of genistein and D-glucose on alpha-glucosidase

Synergetic inhibitory effect of genistein (I2) and D-glucose (I1) on alpha-glucosidase has been studied with kinetics method. It was concluded that the inhibitory effect was much greater when I2 and I1 were both added to the reactant solution simultaneously than that they were added, respectively, which suggesting the inhibitors bind to the different sites of alpha-glucosidase at the same time, and demonstrating synergetic inhibition.     

Catalytic properties of ADAM19

ADAMs are membrane-anchored glycoproteins with functions in fertilization, heart development, neurogenesis, and protein ectodomain shedding. Here we report an evaluation of the catalytic activity of recombinantly expressed soluble forms of ADAM19, a protein that is essential for cardiovascular morphogenesis. Proteolytic activity of soluble forms of ADAM19 was first demonstrated by their autocatalytic removal of a purification tag (Myc-His) and their ability to cleave myelin basic protein and the insulin B chain. The metalloprotease activity of ADAM19 is sensitive to the hydroxamic acid-type metalloprotease inhibitor BB94 (batimastat) but not to tissue inhibitors of metalloproteases (TIMPs) 1-3. Moreover, ADAM19 cleaves peptides corresponding to the known cleavage sites of tumor necrosis factor-alpha (TNF-alpha), TNF-related activation-induced cytokine (TRANCE, also referred to as osteoprotegerin ligand), and kit ligand-1 (KL-1) in vitro. Although ADAM19 is not required for shedding of TNFalpha and TRANCE in mouse embryonic fibroblasts, its overexpression in COS-7 cells results in strongly increased TRANCE shedding. This suggests a potential role for ADAM19 in shedding TRANCE in cells where both molecules are highly expressed, such as in osteoblasts. Interestingly, our results also indicate that ADAM19 can function as a negative regulator of KL-1 shedding in both COS-7 cells and mouse embryonic fibroblasts, instead of acting directly on KL-1. The identification of potential in vitro substrates offers the basis for further functional studies of ADAM19 in cells and in mice.     

Determination of urinary nucleosides by direct injection and coupled-column high-performance liquid chromatography

A coupled-column liquid chromatographic method for the direct analysis of 14 urinary nucleosides is described. Efficient on-line clean-up and concentration of 14 nucleosides from urine samples were obtained by using a boronic acid-substituted silica column (40 mm x 4.0 mm I.D.) as the first column (Col-1) and a Hypersil ODS2 column (250 mm x 4.6 mm I.D.) as the second column (Col-2). The mobile phases applied consisted of 0.25 mol/L ammonium acetate (pH 8.5) on Col-1, and of 25 mmol/L potassium dihydrogen phosphate (pH 4.5) on Col-2, respectively. Determination of urinary nucleosides was performed on Col-2 column by using a linear gradient elution comprising 25 mmol/L potassium dihydrogen phosphate (pH 4.5) and methanol-water (60:40, v/v) with UV detection at 260 nm. Urinary nucleosides analysis can be carried out by this procedure in 50 min requiring only pH adjustment and the protein precipitation by centrifugation of urine samples. Calibration plots of 14 standard nucleosides showed excellent linearity (r > 0.995) and the limits of detection were at micromolar levels. Both of intra- and inter-day precisions of the method were better than 6.6% for direct determination of 14 nucleosides. The validated method was applied to quantify 14 nucleosides in 20 normal urines to establish reference ranges.     

Pincher,a pinocytic chaperone for nerve growth factor/TrkA signaling endosomes

A central tenet of nerve growth factor (NGF) action that is poorly understood is its ability to mediate cytoplasmic signaling, through its receptor TrkA, that is initiated at the nerve terminal and conveyed to the soma. We identified an NGF-induced protein that we termed Pincher (pinocytic chaperone) that mediates endocytosis and trafficking of NGF and its receptor TrkA. In PC12 cells, overexpression of Pincher dramatically stimulated NGF-induced endocytosis of TrkA, unexpectedly at sites of clathrin-independent macropinocytosis within cell surface ruffles. Subsequently, a system of Pincher-containing tubules mediated the delivery of NGF/TrkA-containing vesicles to cytoplasmic accumulations. These vesicles selectively and persistently mediated TrkA-erk5 mitogen-activated protein kinase signaling. A dominant inhibitory mutant form of Pincher inhibited the NGF-induced endocytosis of TrkA, and selectively blocked TrkA-mediated cytoplasmic signaling of erk5, but not erk1/2, kinases. Our results indicate that Pincher mediates pinocytic endocytosis of functionally specialized NGF/TrkA endosomes with persistent signaling potential.     

Formation of dTDP-rhamnose is essential for growth of mycobacteria

It was determined that the dTDP-rhamnose synthesis gene, rmlD, could be inactivated in Mycobacterium smegmatis only in the presence of a rescue plasmid carrying functional rmlD. Hence, dTDP-rhamnose biosynthesis is essential for the growth of mycobacteria and the targeting of dTDP-rhamnose synthesis for new tuberculosis drugs is supported.     

侧柏小孢子的发生和雄配子体的形成

侧柏[Platycladusorientalis（L．）Franco]初生造孢细胞在8月下旬（1992年）形成,11月上旬形成小孢子母细胞,1993年2月中旬形成四分体,2月下旬小孢子从四分体内释放出来,3月中旬形成成熟花粉粒并开始传粉,4月上旬花粉粒在珠心上萌发,5月上旬生殖细胞分裂,6月上旬精原细胞分裂。小孢子母细胞在休眠以前开始减数分裂,解除休眠以后形成成熟的花粒粒。减数分裂从11月上旬开始至次年2月17日结束。小孢子母细胞减数分裂存在扩散双线期。小孢子母细胞以双线期渡过休眠。精原细胞接近颈卵器时开始分裂,形成两个大小相同的精细胞。精细胞独立存在的时间很短。精细胞的细胞质分为三个区域。小孢子母细胞在发育过程中,发现有部分小孢子母细胞退化,在小孢子囊内形成一大的空腔的现象。     

Telomere Dysfunction Disturbs Macrophage Mitochondrial Metabolism and the NLRP3 Inflammasome through the PGC-1α/TNFAIP3 Axis

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