BACKGROUND & AIMS: :A newly implemented G-matrix Fourier transform (GFT) (4,3)D HC(C)CH experiment is presented in conjunction with (4,3)D HCCH to efficiently identify (1)H/(13)C sugar spin systems in (13)C labeled nucleic acids. This experiment enables rapid collection of highly resolved relay 4D HC(C)CH spectral information, that is, shift correlations of (13)C-(1)H groups separated by two carbon bonds. For RNA, (4,3)D HC(C)CH takes advantage of the comparably favorable 1'- and 3'-CH signal dispersion for complete spin system identification including 5'-CH. The (4,3)D HC(C)CH/HCCH based strategy is exemplified for the 30-nucleotide 3'-untranslated region of the pre-mRNA of human U1A protein.

背景与目标： : 结合 (4,3)D HCCH提出了新实施的G矩阵傅里叶变换 (GFT) (4,3)D HC(C)CH实验，以有效地鉴定 (13)C标记核酸中的 (1)H/(13)C糖自旋系统。该实验能够快速收集高度分辨的中继4D HC(C)CH光谱信息，即由两个碳键分开的 (13)C-(1)H基团的移位相关性。对于RNA，(4,3)D HC(C)CH利用相对有利的1 '-和3'-CH信号分散来进行包括5 '-CH的完整自旋系统鉴定。基于 (4,3) dhc (C)CH/HCCH的策略是针对人U1A蛋白的前mRNA的30-核苷酸3 '-非翻译区的例子。

BACKGROUND & AIMS: :Breast cancer is a sex steroid hormone-dependent malignant neoplasia. The role of oestradiol in this malignancy has been well documented; however, the involvement of androgens has remained controversial. To determine the role of non-phenolic androgen metabolites in human breast cancer, we studied the metabolism of [(14)C] testosterone and [(14)C] androstenedione in oestrogen-dependent MCF-7 cells and non-oestrogen-dependent MDA-MB 231 cells, at different substrate concentrations (1-10 muM) and time periods (30 min-48 h). Cultured non-oestrogen-dependent HeLa and yeast cells served as controls. Metabolites were identified and quantified by reverse isotope dilution. A distinctive pattern of androgen metabolism was identified in MCF-7 cells, being the 5alpha-androstane-3alpha,17beta-diol (3alpha,5alpha-diol) and its 3beta epimer (3beta,5alpha-diol), the major conversion products of testosterone (48.3%), with 5alpha-dihydrotestosterone as intermediary. The formation of 3alpha,5alpha-diol and 3beta,5alpha-diol (diols) was substrate concentration- and time-dependent, and abolished by finasteride. In contrast, very little of any diol formation was observed in MDA-MB 231, HeLa and yeast cell incubations. Additional enzyme gene expression studies revealed an overexpression of 5alpha-steroid reductase type-1 in MCF-7 cells, as compared with MDA-MB 231 cells. The oestrogen-like activities of diols were assessed in HeLa cells co-transfected with expression vectors for alpha or beta subtypes of the human oestrogen receptor (hER) genes and for an oestrogen-responsive reporter gene. The results show that 3beta, 5alpha-diol and to a lesser extent 3alpha,5alpha-diol bind with high relative affinity to hERalpha and hERbeta. Both diols induced hER-mediated reporter gene transactivation in a dose-response manner, similar to that induced by oestradiol, though with lower potency, an effect that was abolished by ICI-182 780. Furthermore, 3beta,5alpha-diol and to lesser extent 3alpha,5alpha-diol induced MCF-7 cell proliferation. The overall results demonstrated that MCF-7 cells exhibit enhanced expression and activity of androgen-metabolising enzymes, leading to rapid and large diol formation, and provide evidence that these androgen metabolites exert a potent oestrogen-agonistic effect, at genomic level, in oestrogen-dependent breast cancer cells. The data suggest that diols may act as in situ intracrine factors in breast cancer and that its formation can be pharmacologically inhibited.

背景与目标： 乳腺癌是一种性激素依赖性恶性肿瘤。雌二醇在这种恶性肿瘤中的作用已得到充分证明; 但是，雄激素的参与仍然存在争议。为了确定非酚类雄激素代谢产物在人类乳腺癌中的作用，我们研究了 [(14)C] 睾丸激素和 [(14)C] 雄烯二酮在雌激素依赖性MCF-7细胞和非雌激素依赖性MDA-MB 231细胞中的代谢，在不同的底物浓度 (1-10mum) 和时间段 (30 min-48小时) 下。培养的非雌激素依赖性HeLa和酵母细胞作为对照。通过反向同位素稀释鉴定和定量代谢物。在MCF-7细胞中鉴定出一种独特的雄激素代谢模式，即5α-雄激素-3α，17β-二醇 (3α，5α-二醇) 及其3β 差向异构体 (3β，5α-二醇)，睾丸激素的主要转化产物 (48.3%)，以5α-二氢睾丸激素为中介。3α，5α-二醇和3β，5α-二醇 (二醇) 的形成与底物浓度和时间有关，并被非那雄胺废除。相反，在MDA-MB 231、HeLa和酵母细胞孵育中观察到几乎没有任何二醇形成。另外的酶基因表达研究表明，与MDA-MB 231细胞相比，MCF-7细胞中5α-类固醇还原酶1型过表达。在用人类雌激素受体 (hER) 基因的 α 或 β 亚型和雌激素反应性报告基因的表达载体共转染的HeLa细胞中，评估了二醇的雌激素样活性。结果表明，3β，5α-二醇和在较小程度上3α，5α-二醇与herα 和herβ 具有较高的相对亲和力。两种二醇以剂量反应方式诱导hER介导的报告基因反式激活，类似于雌二醇诱导的，尽管效力较低，但这种作用被ICI-182 780消除。此外，3β，5α-二醇和较小程度的3α，5α-二醇诱导MCF-7细胞增殖。总体结果表明，MCF-7细胞表现出增强的雄激素代谢酶的表达和活性，导致快速和大的二醇形成，并提供证据表明这些雄激素代谢产物在基因组水平上在雌激素依赖性乳腺癌细胞中发挥有效的雌激素激动作用。数据表明，二醇可能在乳腺癌中充当原位内环境因子，并且其形成可以在药理学上受到抑制。

BACKGROUND & AIMS: :Pathways that control aging act via regulated biochemical processes, among which metabolism of xenobiotics (potentially harmful chemical agents encountered as environmental toxicants, for example, drugs, or produced internally) is one possible candidate. A new study of long-lived Ghrhr mutant mice reports that increased bile acid levels activate xenobiotic metabolism via the nuclear receptor, farnesoid X receptor. This increases resistance to xenobiotic stress, possibly contributing to longevity.

背景与目标： : 控制衰老的途径通过调节的生化过程起作用，其中异源生物 (作为环境毒物遇到的潜在有害化学物质，例如药物或内部产生的) 的代谢是一种可能的候选物。一项对长寿命Ghrhr突变小鼠的新研究报告说，胆汁酸水平的增加通过核受体法尼酯X受体激活异源生物代谢。这增加了对异种生物压力的抵抗力，可能有助于延长寿命。

BACKGROUND & AIMS: :Cefpodoxime proxetil is a third generation cephalosporin antibiotic demonstrates pH dependent solubility and is highly soluble only in acidic pH. The purpose of this investigation was to design and develop immediate release tablets of cefpodoxime proxetil by direct compression method and determine the effect of different solid buffers (organic acids) such as fumaric acid (formulations F1-F4), maleic acid (formulations M1-M4) and citric acid (formulations C1-C4) by using cefpodoxime and acid in the ratios of 4:1, 2:1, 1:1 and 1:2 to achieve pH-independent release of the drug. Physical parameters and assay were found to be within the acceptable range as prescribed in USP 36 / NF 31. In vitro dissolution studies of each formulation were performed in distilled water, USP dissolution medium, HCl buffer solution of pH 1.2, phosphate buffer solutions of pH 4.5 and 6.8 to observe the drug release. The formulations F3, F4, M4 were selected for film coating on the basis of better drug release profile, to protect the drug from chemical degradation through hydrolysis. Film coated formulation F3, F4 and M4 showed a remarkable in vitro release of the drug (72.88±0.43 to 92.67±0.71%) within 30min of observation in all dissolution media and further evaluated by model independent and model dependent approaches. The drug release was found to be best fit to Weibull model as highest r2adjusted (0.924-0.998) and lowest AIC (18.416-54.710) values were obtained in all dissolution media. R Gui® applied for stability studies of F3 and F4 formulations, showing shelf lives of 28 & 27months at ambient and 33 months at accelerated temperatures. Formulation F4 was chosen as best formulation on the basis of physical properties, highest dissolution rate and stability studies.

背景与目标： : 头孢泊肟酯是第三代头孢菌素抗生素，具有pH依赖性溶解度，仅在酸性pH下高度可溶。本研究的目的是通过直接压片法设计和开发头孢泊肟酯的速释片剂，并确定不同固体缓冲液 (有机酸) 如富马酸 (配方F1-F4) 的效果。马来酸 (制剂M1-M4) 和柠檬酸 (制剂C1-C4) 通过以4:1，2:1，1:1和1:2的比例使用头孢泊肟和酸来实现药物的pH独立释放。发现物理参数和测定在USP 36 / NF 31规定的可接受范围内。在蒸馏水，USP溶解介质，pH 1.2的HCl缓冲溶液，pH 4.5和6.8的磷酸盐缓冲溶液中进行每种制剂的体外溶出研究，以观察药物释放。基于更好的药物释放特性，选择F3，F4，M4制剂进行薄膜包衣，以保护药物免受水解化学降解。薄膜包衣制剂F3，F4和M4在所有溶解介质中观察30分钟内显示出显着的药物体外释放 (72.88 ± 0.43至92.67 ± 0.71%)，并通过模型独立和模型依赖方法进行进一步评估。发现药物释放最适合Weibull模型，因为在所有溶解介质中获得最高的r2调节值 (0.924-0.998) 和最低的AIC值 (18.416-54.710)。R Gui®适用于F3和F4制剂的稳定性研究，显示在环境下的保质期为28和27个月，在加速温度下的保质期为33个月。根据物理性质，最高溶解速率和稳定性研究，选择配方F4作为最佳配方。

BACKGROUND & AIMS: :In the present study we demonstrate the identification of phenolic compounds and the phenolic contents of the methanol extracts from stem and buds of Calligonum polygonoides with antioxidant activity. Eleven and nine phenolic compounds were identified and quantified from stem and buds, respectively by high-performance liquid chromatography (HPLC). p-Coumaric acid was predominant in stem and gallic acid in buds. In general, the samples with the highest phenolic contents had the highest antioxidant activities. Stem and buds sparked attention due to their high phenolic contents and antioxidant activities. The Results from present study reveal that the C. polygonoides could be considered as a promising source of antioxidant phytochemicals.

背景与目标： : 在本研究中，我们证明了酚类化合物的鉴定以及具有抗氧化活性的caligonum polygonoides茎和芽中甲醇提取物的酚类含量。通过高效液相色谱 (HPLC) 分别从茎和芽中鉴定出11种和9种酚类化合物并对其进行定量。对香豆酸在茎中占主导地位，在芽中占主导地位。通常，酚类含量最高的样品具有最高的抗氧化活性。茎和芽由于其高酚类含量和抗氧化活性而引起了人们的关注。本研究的结果表明，多角藻可被认为是抗氧化剂植物化学物质的有希望的来源。

BACKGROUND & AIMS: :A series of substituted xanthonyloxyacetic acids (5 and 6), 1,2-dihydrofuro[2,3-c]xanthone-2-carboxylic acids (7) and 2,3-dihydrofuro[3,2-b]xanthone-2-carboxylic acids (8) were synthesized and tested for diuretic and uricosuric activities in rats. Most of the xanthon-3-yloxyacetic acids (5) and 7 showed potent diuretic activities, while 8 had lower activities. Uricosuric activities were found in 5c, 5f, 5k, 5m, 5o, 5p, 5r, 7m, 7p and 8q.

背景与目标： : 一系列取代的黄环氧乙酸 (5和6)，1,2-二氢呋喃 [2,3-c]xanthone-2-carboxylic (7) 和2,3-二氢呋喃 [3，合成了2-b]xanthone-2-carboxylic酸 (8) 并测试了大鼠的利尿和尿尿活性。大多数xanthon-3-yloxyacetic酸 (5) 和7表现出强效的利尿活性，而8表现出较低的活性。在5c，5f，5k，5m，5o，5p中发现尿尿活性。5r、7m、7p和8q。

BACKGROUND & AIMS: :Carbon feedstocks from fossilized sources are being rapidly depleted due to rising demand for industrial and commercial applications. Many petroleum-derived chemicals can be directly or functionally substituted with chemicals derived from renewable feedstocks. Several short chain organic acids may fulfill this role using their functional groups as a target for chemical catalysis. Saccharomyces cerevisiae was engineered to produce short chain carboxylic acids (C6 to C10 ) from glucose using the heterologous Homo sapiens type I fatty acid synthase (hFAS). This synthase was activated by phosphopantetheine transfereases AcpS and Sfp from Escherichia coli and Bacillus subtilis, respectively, both in vitro and in vivo. hFAS was produced in the holo-form and produced carboxylic acids in vitro, confirmed by NADPH and ADIFAB assays. Overexpression of hFAS in a yeast FAS2 knockout strain, deficient in de novo fatty acid synthesis, demonstrated the full functional replacement of the native fungal FAS by hFAS. Two active heterologous short chain thioesterases (TEs) from Cuphea palustris (CpFatB1) and Rattus norvegicus (TEII) were evaluated for short chain fatty acid (SCFA) synthesis in vitro and in vivo. Three hFAS mutants were constructed: a mutant deficient in the native TE domain, a mutant with a linked CpFatB1 TE and a mutant with a linked TEII TE. Using the native yeast fatty acid synthase for growth, the overexpression of the hFAS mutants and the short-chain TEs (linked or plasmid-based) increased in vivo caprylic acid and total SCFA production up to 64-fold (63 mg/L) and 52-fold (68 mg/L), respectively, over the native yeast levels. Combined over-expression of the phosphopantetheine transferase with the hFAS mutant resulted in C8 titers of up to 82 mg/L and total SCFA titers of up to 111 mg/L.

背景与目标： : 由于工业和商业应用需求的增长，化石来源的碳原料正在迅速耗尽。许多石油衍生的化学物质可以直接或功能上被可再生原料衍生的化学物质替代。几种短链有机酸可以使用其官能团作为化学催化的目标来发挥这一作用。酿酒酵母经过工程改造，可使用异源智人I型脂肪酸合酶 (hFAS) 从葡萄糖中产生短链羧酸 (C6至C10)。在体外和体内，该合酶分别由来自大肠杆菌和枯草芽孢杆菌的磷酸核苷转染酶AcpS和Sfp激活。通过NADPH和ADIFAB分析证实，hFAS以全型生产并在体外生产羧酸。在缺乏从头脂肪酸合成的酵母FAS2敲除菌株中hFAS的过表达证明了hFAS对天然真菌FAS的完全功能替代。在体外和体内评估了来自Cuphea palustris (CpFatB1) 和Rattus norvegicus (TEII) 的两种活性异源短链硫酯酶 (TEs) 的短链脂肪酸 (SCFA) 合成。构建了三个hFAS突变体: 天然TE结构域缺陷的突变体，CpFatB1 TE连接的突变体和TEII TE连接的突变体。使用天然酵母脂肪酸合酶进行生长，hFAS突变体和短链TEs (连接或基于质粒) 的过表达增加了体内辛酸和总SCFA产量高达64倍 (63  mg/L) 和52倍 (68  mg/L)，分别超过天然酵母水平。磷酸泛氨酸转移酶与hFAS突变体的联合过表达导致C8滴度高达82  mg/L，总SCFA滴度高达111  mg/L。

BACKGROUND & AIMS: :The opiate peptide enkephalin has been immunohistochemically localized within specific populations of climbing fibers and mossy fibers in the opossum's cerebellum. The intention of the present study was to determine the physiological effects of this peptide on Purkinje cell activity as well as to examine interactions between this peptide and the excitatory amino acids glutamate and aspartate. Iontophoretic application of enkephalin onto Purkinje cells in the posterior lobe vermis and adjacent hemisphere suppressed activity in nine of 16 (56%) spontaneously active units. Enkephalin increased the spontaneous activity of one unit and had no effect on six (38%) of the units. In addition, this peptide blocked the excitatory effects elicited by iontophoretic application of glutamate in 34 of 35 (97%) units tested and of aspartate in all cases. Enkephalin had no effect on one cell activated by glutamate. Simultaneous application of naloxone, a nonspecific opiate receptor antagonist, did not block the suppressive effects of enkephalin. Rather, there was a potentiation of suppressive responses as compared to that seen when each is applied alone. The results suggest that classically defined excitatory afferent projections to the cerebellum may be capable of both exciting and suppressing the activity of their target neurons. The excitatory action is likely mediated by an amino acid, whereas the release of the peptide enkephalin results in a decrease in unit activity. Further, it appears that enkephalin mediates its suppressive effect through mechanisms that are not mediated by opioid receptors.

背景与目标： : 鸦片肽脑啡肽已在免疫组织化学上定位在负鼠小脑的攀援纤维和苔藓纤维的特定人群中。本研究的目的是确定该肽对浦肯野细胞活性的生理作用，并检查该肽与兴奋性氨基酸谷氨酸和天冬氨酸之间的相互作用。脑啡肽在后叶ver和邻近半球的浦肯野细胞上的离子电渗应用抑制了16个 (56% 个) 自发活动单位中的9个的活性。脑啡肽增加了一个单位的自发活动，对六个 (38%) 单位没有影响。此外，在所有情况下，该肽阻断了谷氨酸在测试的35 (97%) 单位中的34个和天冬氨酸的离子电渗应用引起的兴奋作用。脑啡肽对谷氨酸激活的一个细胞没有影响。同时应用非特异性阿片受体拮抗剂纳洛酮不会阻止脑啡肽的抑制作用。相反，与单独应用每种方法相比，抑制反应具有增强作用。结果表明，经典定义的对小脑的兴奋性传入投射可能既能够刺激又能够抑制其目标神经元的活动。兴奋作用可能由氨基酸介导，而肽脑啡肽的释放导致单位活性降低。此外，脑啡肽似乎通过阿片受体不介导的机制介导其抑制作用。

BACKGROUND & AIMS: :Dietary intake has been hypothesized to be the major pathway of human exposure to perfluoroalkyl acids (PFAAs). However, difficulties associated with the analysis of PFAAs at ultra trace levels in food samples have prevented the confirmation of this hypothesis. In this study, the dietary intake of PFAAs for the general Swedish population was estimated by applying a highly sensitive analytical method to a set of archived food market basket samples from 1999, 2005 and 2010. Dietary exposure to perfluorooctane sulfonic acid (PFOS) (860-1440 pg kg⁻¹ day⁻¹), perfluoroundecanoic acid (PFUnDA) (90-210 pg kg⁻¹ day⁻¹), perfluorodecanoic acid (PFDA) (50-110 pg kg⁻¹ day⁻¹) and perfluorononanoic acid (PFNA) (70-80 pg kg⁻¹ day⁻¹) was dominated by the consumption of fish and meat. In contrast, dietary exposure to PFOA (350-690 pg kg⁻¹ day⁻¹) originated from low levels (8-62 pg g⁻¹) found in several high consumption food categories including cereals, dairy products, vegetables and fruit. The dietary intakes of PFOS and PFOA estimated in this study were 4 to 10 times lower compared to previous exposure modeling studies. Nevertheless, the dietary intake of PFOS and PFOA was still a factor of 6 to 10 higher than exposure through ingestion of household dust and drinking water estimated for the general Swedish population. For perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA) and perfluorohexane sulfonic acid (PFHxS) drinking water intake was the major exposure pathway (36-53% of the total exposure) whereas dust ingestion made a significant contribution (27-49%) to the total exposure for PFHxA, PFHpA, PFNA, perfluorotridecanoic acid (PFTrDA) and perfluorotetradecanoic acid (PFTeDA). Dietary intakes varied by less than a factor of three for all PFAAs during the different sampling years which demonstrates that dietary intake has been fairly constant over the past decade when many manufacturing changes occurred.

背景与目标： : 饮食摄入被认为是人类接触全氟烷基酸 (PFAAs) 的主要途径。然而，与食品样品中超痕量pfaa分析相关的困难阻碍了这一假设的确认。在这项研究中，通过对1999年，2005和2010的一组存档的食品市场篮子样本应用高度敏感的分析方法，估算了瑞典普通人群的pfaa饮食摄入量。饮食中全氟辛烷磺酸 (PFOS) (860-1440 pg kg-day-¹)，全氟十一酸 (PFUnDA) (90-210 pg kg-¹ day-¹)，全氟癸酸 (PFDA) (50-110 pg kg-day-¹) 和全氟壬酸 (PFNA) (70-80 pg kg-¹ day-¹) 以鱼和肉的消费为主。相比之下，饮食中PFOA的暴露 (350-690 pg kg-day-¹) 源自于几种高消费食品类别 (包括谷物，乳制品，蔬菜和水果) 中的低水平 (8-62 pg g-¹)。与以前的暴露模型研究相比，本研究中估计的全氟辛烷磺酸和全氟辛烷磺酸的饮食摄入量低4至10倍。然而，据估计，全氟辛烷磺酸和全氟辛烷磺酸的饮食摄入量仍比瑞典总人口摄入家庭灰尘和饮用水的暴露量高出6至10倍。对于全氟己酸 (PFHxA)，全氟庚酸 (PFHpA) 和全氟己烷磺酸 (PFHxS)，饮用水摄入量是主要的暴露途径 (占总暴露的36-53%)，而粉尘摄入对PFHxA，PFHpA，PFNA的总暴露有重要贡献 (27-49%)，全氟三癸酸 (PFTrDA) 和全氟十四烷酸 (PFTeDA)。在不同的采样年份中，所有pfaa的饮食摄入量变化不到三倍，这表明在过去十年中，许多制造业发生变化时，饮食摄入量一直相当稳定。

BACKGROUND & AIMS: BACKGROUND & AIMS:Dietary fat intake is related to the degree of obesity, but the specific mechanisms by which fats regulate food intake in humans are unclear. We compared food intake suppression, plasma triglyceride appearance, and cholecystokinin (CCK) response after intestinal infusion of oils enriched with C18 fatty acids of increasing unsaturation. METHODS:Food intake and appetite changes after upper intestinal infusion of 0.9% saline, 20% Intralipid, and 20% emulsions of oils enriched with stearic, oleic, and linoleic acids were tested in 10 healthy male volunteers. Plasma triglyceride appearance and CCK release were tested separately in 7 additional volunteers. RESULTS:Intralipid and linoleic acid infusions significantly reduced food intake compared with saline infusion (P<0.05). No changes were observed in appetite ratings. There were no differences in plasma triglyceride response over the initial 75 minutes of intestinal infusion. Plasma CCK concentration increased after all lipid infusions (P<0.001), Intralipid infusion produced the highest increase in plasma CCK (P<0.05), and CCK response was similar between the 3 enriched oil emulsions. CONCLUSIONS:These results indicate marked differences in the ability of C18 fatty acids to reduce food intake that appear not to be related to rate of absorption but may partially be explained by CCK release.

背景与目标：

BACKGROUND & AIMS: :Dendrotoxins, important pharmacological tools for studying K(+) channels, are potently convulsant in the central nervous system and evidence suggests that different members of the dendrotoxin family may act at pre- or post-synaptic sites. Using a combination of intrahippocampal infusion, microdialysis and electroencephalograph (EEG) recording, we have compared the effects of alpha-dendrotoxin and dendrotoxin K on extracellular levels of excitatory amino acids in anaesthetised rats. Our findings show that although infusion of 35 pmol of both peptides was associated with elevated extracellular aspartate and glutamate, these increased levels were more sustained with dendrotoxin K. Furthermore, there was EEG evidence of an associated transient functional change consistent with an action on pre-synaptic K(+) channels. In contrast, infusion of alpha-dendrotoxin produced only a brief effect on amino acid levels and no evidence of a functional consequence.

背景与目标： : 树状毒素是研究K () 通道的重要药理工具，在中枢神经系统中具有强烈的抽搐作用，有证据表明树状毒素家族的不同成员可能在突触前或突触后位点起作用。使用海马内输注，微透析和脑电图 (EEG) 记录相结合，我们比较了 α-树突毒素和树突毒素K对麻醉大鼠细胞外兴奋性氨基酸水平的影响。我们的发现表明，尽管两种肽的35 pmol输注与细胞外天冬氨酸和谷氨酸升高有关，但树状毒素K会更持久地维持这些升高的水平。此外，脑电图证据表明，与突触前K () 通道的作用相一致的相关瞬时功能变化。相反，输注 α-树状毒素仅对氨基酸水平产生短暂影响，而没有功能性后果的证据。

BACKGROUND & AIMS: :Tetrahymena grown with foreign sterols such as ergosterol incorporate them into cellular membranes at the expense of the native compound, tetrahymanol. It is shown that cells grown with ergosterol have a lessened capacity to produce the polyunsaturated linoleic and gamma-linolenic acids from [14C]oleic acid. However, the same cells have normal capacities to introduce double bonds at C-6 into linoleate, alpha-linolenate, or cis-vaccenate. Thus, a presumed 12-desaturase is inhibited in the presence of ergosterol, while desaturation at C-6 is unaffected.

背景与目标： : 用外来甾醇 (例如麦角甾醇) 生长的四膜虫将它们掺入细胞膜，而牺牲了天然化合物四hymanol。结果表明，用麦角固醇生长的细胞从 [14C] 油酸中产生多不饱和亚油酸和 γ-亚麻酸的能力减弱。然而，相同的细胞具有正常的C-6将双键引入亚油酸酯、 α-亚麻酸酯或顺式疫苗中的能力。因此，在麦角固醇存在下，假定的12-去饱和酶被抑制，而C-6时的去饱和不受影响。

BACKGROUND & AIMS: :Inhibition of urease results in Helicobacter pylori growth arrest in the stomach, promoting urease as promising targets for gastrointestinal ulcer therapy. Twenty hybrid derivatives of flavonoid scaffold and hydroxamic acid, β-hydroxy-β-phenylpropionylhydroxamic acids, were therefore synthesized and evaluated against H. pylori urease. Biological evaluation of these compounds showed improved urease inhibition exhibiting micromolar to mid-nanomolar IC50 values. Most importantly, 3-(3-chlorophenyl)-3-hydroxypropionyl-hydroxamic acid (6g) exhibited high potency with IC50 of 0.083±0.004 μM and Ki of 0.014±0.003 μM, indicating that 6g is an excellent candidate to develop novel antiulcer agent. A mixture of competitive and uncompetitive mechanism was putatively proposed to understand the inconsistency between the crystallographic and kinetic studies for the first time, which is supported by our molecular docking studies.

背景与目标： : 脲酶的抑制导致幽门螺杆菌在胃中的生长停滞，促进脲酶成为胃肠溃疡治疗的有希望的靶标。因此，合成了20种类黄酮支架和异羟肟酸的杂合衍生物，β-羟基-β-苯基丙酰羟肟酸，并对其进行了抗幽门螺杆菌脲酶的评估。这些化合物的生物学评估显示出改善的脲酶抑制作用，表现出微摩尔至中纳摩尔的IC50值。最重要的是，3-(3-氯苯基)-3-羟基丙酰基-异羟肟酸 (6g) 表现出高效能，IC50为0.083 ± 0.004 μ m，Ki为0.014 ± 0.003 μ m，表明6g是开发新型抗溃疡剂的极好候选者。首次提出了竞争性和非竞争性机制的混合，以了解晶体学和动力学研究之间的不一致，这得到了我们分子对接研究的支持。

BACKGROUND & AIMS: :The involvement of phospholipase A2 (PLA2) and fatty acid release in the regulation of sodium-dependent high-affinity choline uptake in rat brain was assessed in vitro through the use of the specific binding of 3H-hemicholinium-3 (3H-HCh-3). Addition of arachidonic acid and other unsaturated fatty acids to rat striatal membranes in vitro resulted in a dose-dependent, temperature-independent activation of 3H-HCh-3 binding. Scatchard analysis revealed that these changes in binding result from a 2-fold increase in the affinity and capacity of 3H-HCh-3 binding. Saturated fatty acids, lysophospholipids, and phospholipids did not affect specific 3H-HCh-3 binding. Addition of defatted BSA to membranes, which had been treated previously with arachidonic acid, completely reversed the increase in specific 3H-HCh-3 binding. However, several inhibitors of fatty acid metabolism, including nordihydroguaiaretic acid, indomethacin, catalase, and superoxide dismutase, did not alter arachidonic acid-induced changes in 3H-HCh-3 binding, suggesting that unsaturated fatty acids, and not their metabolites, are directly responsible for the observed activation of specific 3H-HCh-3 binding. Additionally, unsaturated fatty acids dose-dependently inhibited high-affinity 3H-choline uptake in rat striatal synaptosomes, apparently due to the disruption of synaptosomal integrity. The phospholipase A2 inhibitors quinacrine hydrochloride, trifluoperazine, and 4-bromophenacylbromide dose-dependently inhibited potassium depolarization-induced activation of specific 3H-HCh-3 binding in slices of rat brain in vitro. Similarly, both quinacrine and trifluoperazine inhibited the metabolism of phospholipids and the release of fatty acids evoked by either elevated KCl or calcium ionophore A23187. These results support the involvement of PLA2 and subsequent fatty acid release in the increase of 3H-HCh-3 binding in cholinergic neurons and suggest that activation of PLA2 may be the penultimate step in regulating the velocity of sodium-dependent choline transport.

背景与目标： : 通过使用3h-hemichholinium-3 (3h-hchh-3) 的特异性结合，在体外评估了磷脂酶A2 (PLA2) 和脂肪酸释放在调节钠依赖性高亲和力胆碱摄取中的参与。hch-3)。在体外向大鼠纹状体膜中添加花生四烯酸和其他不饱和脂肪酸会导致3H-HCh-3结合的剂量依赖性，温度依赖性激活。Scatchard分析表明，结合的这些变化是由3H-HCh-3结合的亲和力和能力增加2倍引起的。饱和脂肪酸，溶血磷脂和磷脂不影响特定的3H-HCh-3结合。将脱脂的BSA添加到先前用花生四烯酸处理过的膜中，完全逆转了特异性3H-HCh-3结合的增加。然而，脂肪酸代谢的几种抑制剂，包括去甲二氢愈创木酸，吲哚美辛，过氧化氢酶和超氧化物歧化酶，并未改变花生四烯酸诱导的3H-HCh-3结合的变化，这表明不饱和脂肪酸而不是其代谢物直接导致观察到的3H-HCh-3结合的激活。此外，不饱和脂肪酸剂量依赖性地抑制了大鼠纹状体突触小体中高亲和力的3h-胆碱摄取，这显然是由于突触小体完整性的破坏。磷脂酶A2抑制剂盐酸奎纳克林，三氟拉嗪和4-溴苯甲酰溴在体外大鼠脑切片中剂量依赖性地抑制钾去极化诱导的特异性3H-HCh-3结合的激活。同样，奎纳克林和三氟拉嗪均抑制磷脂的代谢以及升高的KCl或钙离子载体a23187引起的脂肪酸的释放。这些结果支持PLA2和随后的脂肪酸释放参与胆碱能神经元中3H-HCh-3结合的增加，并表明PLA2的激活可能是调节钠依赖性胆碱转运速度的倒数第二步。

BACKGROUND & AIMS: :Protein isoprenylation is a lipid posttranslational modification required for the function of many proteins that share a carboxyl-terminal CAAX motif. The X residue determines which isoprenoid will be added to the cysteine. When X is a methionine or serine, the farnesyl-transferase transfers a farnesyl, and when X is a leucine or isoleucine, the geranygeranyl-transferase I, a geranylgeranyl group. But despite its CKVL motif, RhoB was reported to be both geranylgeranylated and farnesylated. Thus, the determinants of RhoB prenylation appear more complex than initially thought. To determine the role of RhoB CAAX motif, we designed RhoB mutants with modified CAAX sequence expressed in baculovirus-infected insect cells. We demonstrated that RhoB was prenylated as a function of the three terminal amino acids, i.e., RhoB bearing the CAIM motif of lamin B or CLLL motif of Rap1A was farnesylated or geranylgeranylated, respectively. Next, we produced a specific polyclonal antibody against farnesyl cysteine methyl ester allowing prenylation analysis avoiding the metabolic labeling restrictions. We confirmed that the unique modification of the RhoB CAAX box was sufficient to direct the RhoB distinct prenylation in mammalian cells and, inversely, that a RhoA-CKVL chimera could be alternatively prenylated. Moreover, the immunoprecipitation of endogenous RhoB from cells with the anti-farnesyl cysteine antibody suggested that wild-type RhoB is farnesylated in vivo. Taken together, our results demonstrated that the three last carboxyl amino acids are the main determinants for RhoB prenylation and described an anti-farnesyl cysteine antibody as a useful tool for understanding the cellular control of protein farnesylation.

背景与目标： : 蛋白质异戊二烯化是一种脂质翻译后修饰，是许多具有羧基末端CAAX基序的蛋白质的功能所需的。X残基决定了哪些类异戊二烯将被添加到半胱氨酸中。当X是蛋氨酸或丝氨酸时，法尼基转移酶转移法尼基，而当X是亮氨酸或异亮氨酸时，香叶香叶基转移酶I，香叶香叶基。但是，尽管有CKVL基序，但据报道RhoB既被香叶基化又被法尼基化。因此，RhoB异戊烯化的决定因素似乎比最初认为的更复杂。为了确定RhoB CAAX基序的作用，我们设计了具有在杆状病毒感染的昆虫细胞中表达的修饰CAAX序列的RhoB突变体。我们证明了RhoB作为三个末端氨基酸的函数被异戊二烯化，即带有lamin B的CAIM基序或Rap1A的CLLL基序的RhoB分别被法呢基化或香叶基化。接下来，我们产生了针对法呢基半胱氨酸甲酯的特异性多克隆抗体，从而可以进行异戊烯化分析，从而避免了代谢标记的限制。我们证实，RhoB CAAX盒的独特修饰足以在哺乳动物细胞中引导RhoB独特的异戊烯化，并且相反，RhoA-CKVL嵌合体可以替代异戊烯化。此外，用抗法尼基半胱氨酸抗体从细胞中免疫沉淀内源性RhoB表明，野生型RhoB在体内被法尼基化。合在一起，我们的结果表明，最后三个羧基氨基酸是RhoB异戊烯化的主要决定因素，并描述了抗法尼基半胱氨酸抗体作为了解蛋白质法尼基化的细胞控制的有用工具。