GS15 forms a SNARE complex with syntaxin 5, GS28, and Ykt6 and is implicated in traffic in the early cisternae of the Golgi apparatus

The subcellular localization, interacting partners, and function of GS15, a Golgi SNARE, remain to be established. In our present study, it is revealed that unlike proteins (Bet1 and the KDEL receptor) cycling between the Golgi and the intermediate compartment (IC, inclusive of the ER exit sites), GS15 is not redistributed into the IC upon incubation at 15 degrees C or when cells are treated with brefeldin A. Immuno-electron microscopy (immuno-EM) reveals that GS15 is mainly found in the medial-cisternae of the Golgi apparatus and adjacent tubulo-vesicular elements. Coimmunoprecipitation experiments suggest that GS15 exists in a distinct SNARE complex that contains SNAREs (syntaxin5, GS28, and Ykt6) that are implicated in both ER-to-Golgi and intra-Golgi transport but not with SNAREs involved exclusively in ER-to-Golgi traffic. Furthermore, components of COPI coat can be selectively coimmunoprecipitated with GS15 from Golgi extracts. Overexpression of mutant forms of GS15 affects the normal distribution of cis- and medial-Golgi proteins (GS28, syntaxin 5, and Golgi mannosidase II), whereas proteins of the trans-Golgi and TGN (Vti1-rp2/Vti1a and syntaxin 6) and Golgi matrix/scaffold (GM130 and p115) are less affected. When the level of GS15 is reduced by duplex 21-nt small interfering RNA (siRNA)-mediated knockdown approach, diverse markers of the Golgi apparatus are redistributed into small dotty and diffuse labeling, suggesting an essential role of GS15 in the Golgi apparatus.     

EPR studies on the superoxide-scavenging capacity of the nutraceutical resveratrol

Resveratrol (3,4',5-trihydroxystilbene), a polyphenolic compound found in mulberries, grapes, and red wine, has received considerable attention because of its apparent protective effects against various degenerative diseases due to its potential antioxidant activities. However, direct evidence for the superoxide-scavenging capacity of resveratrol is lacking in literature. In this study, electron paramagnetic resonance spectroscopy in combination with 5-(diethoxyphosphoryl)-5-methylpyrroline-N-oxide (DEPMPO)-spin trapping technique was utilized to determine the ability of resveratrol in scavenging superoxide anions generated from both potassium superoxide and the xanthine oxidase/xanthine system. We have demonstrated here for the first time that the presence of resveratrol resulted in decreased formation of DEPMPO-superoxide adduct (DEPMPO-OOH) in both the potassium superoxide and xanthine oxidase/xanthine systems, indicating that resveratrol could directly scavenge superoxide anions. The inhibition of DEPMPO-OOH in the xanthine oxidase/xanthine system, however, was found to be much potent as compared to that observed in potassium superoxide system. It was further shown that resveratrol could also directly inhibit xanthine oxidase activity as assessed by oxygen consumption and formation of uric acid. Taken together, the dual role of resveratrol in directly scavenging superoxide and inhibiting its generation via xanthine oxidase reported in this study may explain, at least in part, the protective role of this compound against oxidative injury in various disease processes.     

Generation of <Emphasis Type="Italic">Vibrio anguillarum</Emphasis> Ghost by Coexpression of PhiX 174 Lysis <Emphasis Type="Italic">E</Emphasis> gene and Staphylococcal Nuclease <Emphasis Type="Italic">A</Emphasis> Gene

Vibrio anguillarum ghosts (VAG) were generated, for the first time, using a conjugation vector containing a ghost bacteria inducing cassette, pRK-λP_R-cI-Elysis, in which the expression of PhiX174 lysis gene E was controlled by the P _R /cI regulatory system of lambda phage. By scanning electron microscopy, holes ranging 80–200 nm in diameter were observed in the VAG. To avoid the presence of bacterial genomic DNA and an antibiotic resistance gene in the final VAG product, we constructed a new dual vector, pRK-λP_R-cI-E-SNA, containing the E-mediated lysis cassette and the staphylococcal nuclease A (SNA)-mediated DNA degradation cassette, and generated safety-enhanced VAG for use as a fish vaccine.     

The promoter of the pepper pathogen-induced membrane protein gene <Emphasis Type="Italic">CaPIMP1</Emphasis> mediates environmental stress responses in plants

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-β-glucuronidase (GUS) gene fusion, serially 5′-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The −1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The −417- and −593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than −793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments. CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, β-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast, transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages. These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection. The nucleotide sequence data reported here has been deposited in the GenBank database under the accession number DQ356279.     

Combinatory responses of proinflamamtory cytokines on nitric oxide-mediated function in mouse calvarial osteoblasts

Combinatory responses of proinflamamtory cytokines have been examined on the nitric oxide-mediated function in cultured mouse calvarial osteoblasts. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) induced iNOS gene expression and NO production, although these actions were inhibited by L-NG-monomethylarginine (L-NMMA) and decreased alkaline phosphatase (ALPase) activity. Furthermore, NO donors, sodium nitroprusside (SNP) and NONOate dose-dependently elevated ALPase activity. In contrast, transforming-growth factor-β (TGF-β) decreased NO production stimulated by IL-1β, TNF-α and interferon-γ (IFN-γ). iNOS was expressed by mouse calvarial osteoblast cells after stimulation with IL-1β, TNF-α, and IFN-γ. Incubation of mouse calvarial osteoblast cells with the cytokines inhibited growth and ALPase activity. However, TGF-β-treatment abolished these effects of IL-1β, TNF-α and IFN-γ on growth inhibition and stimulation of ALPase in mouse calvarial osteoblast cells. In contrast, IL-1β, TNF-α, and IFN-γ exerted growth-inhibiting effects on mouse calvarial osteoblast cells which were partly NO-dependent. The results suggest that NO may act predominantly as a modulator of cytokine-induced effects on mouse calvarial osteoblast cells and TGF-β is a negative regulator of the NO production stimulated by IL-1β, TNF-α and IFN-γ.     

N-糖基化位点突变的人IFN-λ1在毕赤酵母中的表达、纯化及表征

IFN-λ1是Ⅲ型干扰素家族的一个成员,具有与Ⅰ型干扰素相似的功能。此前,我们已经从毕赤酵母表达获得了可溶性重组人干扰素-λ1。然而,毕赤酵母表达中的高糖基化带来了免疫原性,影响了蛋白质的生产纯化效率。为了克服这个缺点,文中构建了一种干扰素突变体 (rhIFN-λ1-Nm),定点突变潜在糖基化位点。AOX1启动子与α因子信号序列存在的情况下,用甲醇诱导成功地实现了rhIFN-λ1-Nm在毕赤酵母GS115胞外分泌表达。对rhIFN-λ1-Nm进行纯化,获得了纯度>98%的产品,并对糖化水平、分子量、二级结构、N末端序列等理化性质和生物活性进行了研究。研究结果表明,rhIFN-λ1-Nm糖基化水平明显降低,蛋白质生产纯化收率显著提高,而对结构和生物活性无影响;糖基化位点突变rhIFN-λ1可以被开发为IFN-λ1的替代品,有望发展成为未来的生物免疫制剂。     

利用激光扫描共聚焦显微镜研究视皮层脑片长时程增强过程中核酸的变化

本文使用 1 5— 2 0天龄幼年大鼠视皮层脑片的标本 ,在通氧状态下 ,用荧光探针 AO染色 ,激光扫描共聚焦显微镜对全脑片不同层面进行共聚焦断层扫描 ,沿纵轴每 2 0μm扫一次 ,共扫描 1 6次。再利用总值方式的投影算法对其三维重建 ,分析幼年大鼠视皮层脑片长时程增强过程中核酸的变化。     

An expression profile of human α-lactalbumin in the milk of transgenic mouse

a-lactalbumin(a-Lac),amajorwheyprotein,isacalciummetalloprotein,thathasbeenfoundinallmilksstudiedsofar.ItinteractswithUDP-galactosyl-transferasetoformthelactosesynthetaseandthusmightbeakeyproteinforlactogenesis.Lactosesyn-thetaseispostulatedtobetherate-limitingenzymeforlactosebiosynthesis.Theincreaseda-Lacactivitycanproducesufficientlactosesynthetaseforthesynthesisoflactose,andinmilkyieldbydrawingwaterintomilk,sincelactoseisanosmoreactivemolecule.Transgenicswineoverexpressingbovinea-lactalbu…     

社鼠组织器官同工酶的研究

用聚丙烯酰胺凝胶等电聚焦电泳方法,分析了社鼠的肝、肾、心肌、骨骼肌、肺、脾和脑等多种组织器官的ＬＤＨ、ＡＤＨ、ＥＳＴ、和ＳＯＤ４种同工酶,对各组织器官的酶带数目和分布,以及酶活性进行了比较研究。结果表明,社鼠的ＬＤＨ同工酶、ＡＤＨ同工酶和ＥＳＴ同工酶具有比较明显的组织特异性,而ＳＯＤ同工酶的组织特异性较低。肺和脾除ＥＳＴ同工酶活性较高外,脑除ＬＤＨ同工酶活性较高外,其它３种同工酶的活性均较低;而肝和肾中４种同工酶的活性普遍很高。心肌和骨骼肌因氧张力不同而使ＬＤＨ同工酶酶谱存在明显差异,但其它３种同工酶酶谱却非常相似。同工酶的组织特异性与各组织器官所执行的生理功能是相一致的