2′-(E)-O-p-coumaroylgalactaric acid and 2′-(E)-O-feruloylgalactaric acid in citrus

2′-(E)-O-p-Coumaroyl- and 2′-(E)-O-feruloylgalactaric acids, hitherto unknown in nature, have been isolated and identified from orange peel.     

普通冠状病毒229E株的分子流行病学分析

目的明确哈尔滨地区普通冠状病毒229E(Human Coronavirus-229E,HCOV-229E)株的流行和变异情况及其与SARS-CoV的异同,为进一步掌握该地区常见上呼吸道病毒的流行规律及预防,乃至疫苗的制备打下基础。方法利用RT—PCR法对2003年上半年采集的部分发热病人血清及血细胞进行筛选,同时采用基因测序、序列分析等手段对扩增的HCOV-229E N gene片断进行蛋白和基因分析。结果55例标本中HCOV-229E RNA阳性病例5例,占9．09％;测序结果看出哈尔滨地区检出229E株N基因的序列与已公布的HCOV-229E Ngene(295—802)序列完全相同,所测片断为HCOV-229E N gene的部分序列。该基因与猪流行性腹泻病毒、犬冠状病毒、TGEV及猫感染性腹膜炎病毒有一定同源性;但与已公布的SARS-CoV N gene序列比较,相似性小于1％。结论(1)该地区发热病人普通冠状病毒229E株阳性率为9．09％;(2)哈尔滨地区流行的HCOVN基因无变异发生;(3)HCOV-229E与猪流行性腹泻病毒、犬冠状病毒、TGEV和猫感染性腹膜炎病毒有一定的同源性;(4)哈尔滨地区HCOV-229E N gene与SARS-CoV N gene相似性小于1％。     

Total synthesis of (±)-elegansidiol, (±)-farnesiferol B,and (±)-farnesiferol D

The racemic total synthesis of elegansidiol, farnesiferol B, and farnesiferol D has been obtained following a Diels–Alder approach. Gillman addition, cross metathesis reaction are the other key steps involved in the target synthesis.     

(E)-2,4-Bis(p-hydroxyphenyl)-2-butenal inhibits tumor growth via suppression of NF-κB and induction of death receptor 6

The Maillard reaction products are known to be effective in chemoprevention. Here, we focused on the anti-cancer effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal on in vitro and in vivo colon cancer. We analysed the anti-cancer activity of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal on colon cancer cells by using cell cycle and apoptosis analysis. To elucidate it’s mechanism, NF-κB DNA binding activity, docking model as well as pull-down assay. Further, a xenograft model of colon cancer was studied to test the in vivo effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal. (E)-2,4-Bis(p-hydroxyphenyl)-2-butenal inhibited colon cancer cells (SW620 and HCT116) growth followed by induction of apoptosis in a concentration-dependent manner via down-regulation of NF-κB activity. In docking model as well as pull-down assay, (E)-2,4-bis(p-hydroxyphenyl)-2-butenal directly binds to three amino acid residues of IKKβ, thereby inhibited IKKβ activity in addition to induction of death receptor 6 (DR6) as well as their target apoptotic genes. Finally, (E)-2,4-bis(p-hydroxyphenyl)-2-butenal suppressed anchorage-independent cancer cell growth, and tumor growth in xenograft model accompanied with apoptosis through inhibition of IKKβ/NF-κB activity, and overexpression of DR6. These results suggest that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal inhibits colon cancer cell growth through inhibition of IKKβ/NF-κB activity and induction of DR6 expression.     

阿扎霉素B(Azalomycin B)研究进展

介绍阿扎霉素B的生物学来源,研究历史,主要理化性质和结构确定,同时阐述了阿扎霉素B的生物合成途径,构效关系,生物学特性和应用前景。     

冠状病毒HCoV-229E S1蛋白片段的免疫原性分析

目的表达和纯化HCoV-229E的S1蛋白片段（S1 417-547）,分析其诱导的免疫应答。方法将纯化蛋白免疫小鼠,ELISA检测小鼠血清特异性抗体以及血清IL-4和IFN-γ含量,流式细胞术检测小鼠脾脏T淋巴细胞亚群分布,观察其诱导的免疫应答。结果表达蛋白经金属螯合获得纯化,并诱导小鼠产生了高滴度的抗体。脾脏CD4^＋和CD8^＋比例均升高,CD4^＋/CD8^＋比值下降;免疫鼠血清IFN-γ和IL-4水平显著升高。结论成功构建了HCoV-229E S1蛋白的表达载体,并在BL21（DE3）中得到了高效表达,表达蛋白免疫小鼠后诱导了明显的细胞和体液免疫应答。     

Variable synthesis and expression of E β and A e (E β ) Ia polypeptide chains in mice of differentH-2 haplotypes

The genetic and molecular requirements for cell-surface expression of Ia antigens precipitated by anti-I-E subregion sera have been examined. Inbred mice of thed, k, p, andr haplotypes synthesize and express on their lymphocytes the two I-region products normally found in anti-I-E-subregion immunoprecipitates, E and A_e (E ). Cells from mice of theb ands haplotypes fail to synthesize E chains but do synthesize A_e chains, which remain in the cytoplasm as partially glycosylated precursors. Cells of thef andq haplotypes fail to synthesize either the A_e or E polypeptide chains, as shown by both genetic complementation tests and analyses of total cell proteins by two-dimensional polyacrylamide gel electrophoresis. The patterns of expression of the intact E :A_e complex are consistent with the theory that both the A_e and E polypeptide chains must be present in the cells for either chain to be expressed in normal amounts on the cell surface. The implications of these observations for the genetics ofI-region-controlled functions are discussed.     

Leg Cramps (Systremma) and “Restless Legs” Syndrome — Response to Vitamin E (Tocopherol)

A clinical investigation into the therapeutic value of vitamin E (tocopherol) in certain dermatological conditions of obscure etiology led to the incidental observation that this compound produced beneficial effects in some of the patients who were suffering from frequent and severe nocturnal leg cramps. Nearly all of the patients with leg cramps received prompt and gratifying relief from their symptoms while taking vitamin E in the form of d, alpha-tocopheryl acetate, 100 I.U. three times a day before meals. The group included 24 private patients with leg cramps and two with the “restless legs” syndrome, probably a related condition. One of the patients with leg and foot cramps also had severe nocturnal rectal cramps which were also relieved.Nocturnal leg cramps constitute a relatively common complaint in the general practice of medicine and may be very distressing to the patient. Not only is the cause obscure and the treatment relatively unsatisfactory, but even its proper medical name, systremma (anything twisted up together), is unknown to most physicians.     

Stereospecific Synthesis and Anti-HIV Activity of (Z)2′- and (E)3′-Deoxy-2′(3′)-C-(chloromethylene) Pyrimidine Nucleosides

Abstract

Reaction of 1-[2,5(and 3,5)-di-O-trityl-β-D-erythro-pentofuran-3 (and 2)-ulosyl]uracil derivatives 5 and 6 with (chloromethyl)triphenylphosphorane resulted in the stereoselective formation of (E)-3′- and (Z)-2′-chloromethylene derivatives 7 (69%) and 8 (53%), respectively, deprotection of which gave 9 and 10. Transformation of the uracil nucleoside 7 into cytosine one followed by deprotection yielded 12. The latter was converted into the arabinoside 14. The fully deprotected chloromethylene nucleosides were tested for their activity against HIV-1 and HIV-2.     

Microbiological synthesis of 5-ethyl- and (E)-5-(2-bromovinyl)-2′-deoxyuridine

Summary The title compounds were prepared by an enzymatic transdeoxyribosylation from 2 dGuo or 2 dThd to the respective heterocyclic bases, 5-ethyluracil and (E)-5-(2-bromovinyl)uracil, using the whole bacterial cells ofEscherichia coli as a biocatalyst.     

Analysis of nuclear factor-κB (NF-κB) essential modulator (NEMO) binding to linear and lysine-linked ubiquitin chains and its role in the activation of NF-κB

Nuclear factor-κB (NF-κB) essential modulator (NEMO), a component of the inhibitor of κB kinase (IKK) complex, controls NF-κB signaling by binding to ubiquitin chains. Structural studies of NEMO provided a rationale for the specific binding between the UBAN (ubiquitin binding in ABIN and NEMO) domain of NEMO and linear (Met-1-linked) di-ubiquitin chains. Full-length NEMO can also interact with Lys-11-, Lys-48-, and Lys-63-linked ubiquitin chains of varying length in cells. Here, we show that purified full-length NEMO binds preferentially to linear ubiquitin chains in competition with lysine-linked ubiquitin chains of defined length, including long Lys-63-linked deca-ubiquitins. Linear di-ubiquitins were sufficient to activate both the IKK complex in vitro and to trigger maximal NF-κB activation in cells. In TNFα-stimulated cells, NEMO chimeras engineered to bind exclusively to Lys-63-linked ubiquitin chains mediated partial NF-κB activation compared with cells expressing NEMO that binds to linear ubiquitin chains. We propose that NEMO functions as a high affinity receptor for linear ubiquitin chains and a low affinity receptor for long lysine-linked ubiquitin chains. This phenomenon could explain quantitatively distinct NF-κB activation patterns in response to numerous cell stimuli.     

冠状病毒HcoV-229E S1蛋白的原核表达及鉴定

目的克隆表达冠状病毒HcoV-229E S1基因片段,表达S1蛋白。方法合成冠状病毒HcoV-229ES1蛋白特异性基因片段并克隆入pET21a原核表达载体,转化BL21（DE3）菌,经IPTG高效诱导表达得到重组蛋白,用金属螯合亲和层析纯化,并通过Western blot对表达的重组蛋白进行鉴定。结果获得了主要以包涵体形式存在的目的蛋白,Western blot鉴定其为S1基因片段蛋白。结论成功构建了HcoV-229E S1蛋白的表达载体,并在BL21（DE3）中得到了高效表达,为下一步表达蛋白免疫原性及疫苗抗病毒保护性测定打下了基础。     

(E160A)和(E160D)天花粉蛋白两种突变体晶体结构研究

培养了（Ｅ１６０Ａ）ＴＣＳ和（Ｅ１６０Ｄ）ＴＣＳ的单晶。在ＭＡＲＲｅｓｅａｒｃｈ面探测器系统上分别收集了０．１９３ｎｍ和０．２０ｎｍ分辨率的Ｘ射线衍射数据。数据处理用ＭＡＲＳＣＡＬＥ程序系统完成。用同晶差值Ｆｏｕｒｉｅｒ法解析了突变体的晶体结构,结构修正利用Ｘ－ＰＬＯＲ程序。修正结果,晶体学Ｒ因子分别为０．１７５,０．１７９,键长和键角的ＲＭＳ偏差分别为０．００１１ｎｍ和２．４５７°,０．００１３ｎｍ和２．６７５°。在这两个突变体的结构中均未见到Ｇｌｕ１８９侧链方向的改变。通过对（Ｅ１６０Ａ）ＴＣＳ和（Ｅ１６０Ｄ）ＴＣＳ的结构比较,说明（Ｅ１６０Ｄ）ＴＣＳ活性低于（Ｅ１６０Ａ）ＴＣＳ的原因：这可能是由于在（Ｅ１６０Ｄ）ＴＣＳ中Ｔｙｒ１１１和Ｔｙｒ７０的侧链都具有较大的运动性,使它们与腺嘌呤碱基的芳香堆垛作用减弱,从而导致活性的降低     

Palmitate-induced PTP1B expression is mediated by ceramide-JNK and nuclear factor κB (NF-κB) activation

Palmitate induces PTP1B expression in skeletal muscle cells. The purpose of this study was to investigate the mechanisms responsible for palmitate-induced PTP1B expression in mouse skeletal muscle cells. Three truncated fragments of PTP1B promoter were cloned into PGL3-basic vector and the promoter activity of PTP1B was assessed in C2C12 cells exposed to palmitate either in the presence or in the absence of several inhibitors to study the biochemical pathways involved. EMSA was performed to examine binding of NF-κB to NF-κB consensus sequence and PTP1B oligonucelotides in the cells treated with palmitate. Lentiviral PTP1B-shRNA was used to knockdown PTP1B in myotubes. The phosphorylation and protein levels of IRS-1 and Akt were detected by western blot. 0.5mM palmitate induced PTP1B promoter activity in fragment -1715/+59 by 50% (p<0.01). Palmitate increased NF-κB binding to both NF-κB consensus sequence and one NF-κB sequence (-920 to -935) in PTP1B promoter. Incubation of C2C12 cells with different concentrations of C2-ceramide enhanced PTP1B promoter activity dose-dependently. Inhibitors of de novo ceramide synthesis prevented palmitate-induced PTP1B promoter activity in myotubes. In addition, inhibitor of JNK pathway prevented ceramide-induced PTP1B promoter activity in myotubes. Knockdown of PTP1B also prevented ceramide-reduced IRS-1 and Akt phosphorylations in the myotubes. Exposure of the cells to PMA and calphostin C, an inhibitor of PKC, did not affect the activity of PTP1B promoter. Our data provide the evidence that the mechanism by which palmitate increased the expression of PTP1B seems to be through a mechanism involving the activation of ceramide-JNK and NF-κB pathways.     

Metabolism of (2Z,4E)-γ-Ionylideneethanol and (2Z,4E)-γ-Ionylideneacetic Acid in Cercospora cruenta

[2–¹⁴C]-(2Z,4E)-γ-Ionylideneethanol and [2–¹⁴C]-(2Z,4E)-γ-ionylideneacetic acid were converted by Cercospora cruenta to [2–¹⁴C]-(2Z,4E)-1′,4′-dihydroxy-γ-ionylideneacetic acid and [2-¹⁴C]-(2Z,4E)-4′-hydroxy-γ-ionylideneacetic acid, which are intermediates of ABA biosynthesis in C. cruenta.     

Expression of Inhibin/activin Subunits alpha (-α), beta A (-β A) and beta B (-β B) in Placental Tissue of Normal and Intrauterine Growth Restricted (IUGR) Pregnancies

During human pregnancy the placenta produces a variety of proteins like steroid hormones and their receptors that are responsible for the establishment and ongoing of the feto-placental unit. Inhibins are dimeric glycoproteins, composed of an α-subunit and one of two possible β-subunits (β _A or β _B). Aims of the present study were the determination of the frequency and tissue distribution patterns of the inhibin/activin subunits in human placental tissue of normal pregnancies and pregnancies complicated with fetal growth restriction (IUGR). Slides of paraffin embedded placental tissue were obtained after delivery from patients diagnosed with IUGR (n = 6) and normal term placentas (n = 8). Tissue samples were fixed and incubated with monoclonal antibodies inhibin/activin-subunits -α, -β _A, -β _B. Intensity of immunohistochemical reaction on the slides was analysed using a semi-quantitative score and statistical analysis was performed (P<0.05). A significant lower expression of the inhibin-α subunit in IUGR extravillous trophoblast compared to normal pregnancies was observed, while the inhibin-α immunostaining was significantly upregulated in syncytiotrophoblast. Additionally, a significant down-regulation of inhibin-β _B subunit in extravillous trophoblast cells in IUGR syncytiotrophoblast cells was demonstrated. A co-localisation of inhibin-α and the β-subunits was also observed, suggesting a production and secretion of intact inhibin A and inhibin B. Although the precise role of these inhibin/activin subunits in human placenta and IUGR pregnancies is still unclear, they could be involved in autocrine/paracrine signalling, contributing to several aspects like angiogenesis and tissue remodelling.     

Nitric oxide modulates sodium vitamin C transporter 2 (SVCT-2) protein expression via protein kinase G (PKG) and nuclear factor-κB (NF-κB)

Ascorbate is an important antioxidant, which also displays important functions in neuronal tissues, including the retina. The retina is responsible for the initial steps of visual processing, which is further refined in cerebral high-order centers. The retina is also a prototypical model for studying physiologic aspects of cells that comprise the nervous system. Of major importance also is the cellular messenger nitric oxide (NO). Previous studies have demonstrated the significance of NO for both survival and proliferation of cultured embryonic retinal cells. Cultured retinal cells express a high-affinity ascorbate transporter, and the release of ascorbate is delicately regulated by ionotropic glutamate receptors. Therefore, we proposed whether there is interplay between the ascorbate transport system and NO signaling pathway in retinal cells. Here we show compelling evidence that ascorbate uptake is tightly controlled by NO and its downstream signaling pathway in culture. NO also modulates the expression of SVCT-2, an effect mediated by cGMP and PKG. Kinetic studies suggest that NO increases the transport capacity for ascorbate, but not the affinity of SVCT-2 for its substrate. Interestingly, NO utilizes the NF-κB pathway, in a PKG-dependent manner, to modulate both SVCT-2 expression and ascorbate uptake. These results demonstrate that NO exerts a fine-tuned control of the availability of ascorbate to cultured retinal cells and strongly reinforces ascorbate as an important bioactive molecule in neuronal tissues.