Formation of 9-hydroxy linoleic acid as a product of phospholipid peroxidation in diabetic erythrocyte membranes

The increased production of oxygen-derived free radicals (OFR) and lipid peroxidation may contribute to vascular complications in diabetes. Some lipid peroxidation products have already been reported to be formed via glucose-induced oxidative stress. We have identified 9-hydroxy linoleic acid (9-OH-C18:2) in the red cell membrane phospholipid of diabetic subjects. We hypothesized that 9-OH-C18:2 would be formed in hydroxyl radical reactions to linoleic acid (C18:2) during glucose-induced oxidative stress, and confirmed that the formation of 9-OH-C18:2 was induced by ultraviolet (UV)-C irradiation to the synthetic C18:2. UV-C light generates highly reactive hydroxy radicals. C18:2 is confirmed to be the precursor of 9-OH-C18:2. To estimate the degree of oxidative damage to red cell membrane phospholipids, we developed a selective ion monitoring gas chromatography-mass spectrometric measurement for C18:2 and 9-OH-C18:2, following methanolysis of red cell membrane phospholipids. The relative peak height ratio of C18:2 to 9-OH-C18:2 (9-OH-C18:2/C18:2) was measured in phospholipid extracts of red cell membranes from healthy (n=29, 3.1±1.9%) and diabetic (n=27, 20.9±16.1%) subjects. It was confirmed that 9-OH-C18:2/C18:2 is significantly (P<0.001) elevated in patients with diabetes. The measurement of 9-OH-C18:2/C18:2 in red cell membranes should be useful for assessing oxidative damage to membrane phospholipids in diabetes.     

西藏块菌属的分类研究

首次报道产于西藏的块菌属３种,包括２个新种和１个新记录种。新种是刘氏块菌ＴｕｂｅｒｌｉｕｉＡ．Ｓ．Ｘｕｓｐ．ｎｏｖ．和西藏块菌ＴｕｂｅｒｘｉｚａｎｇｅｎｓｅＡ．Ｓ．Ｘｕｓｐ．ｎｏｖ,新记录种是少孢块菌Ｔｕｂｅｒｏｌｉｇｏｓｐｅｒｍｕｍ（Ｔｕｌ．＆Ｃ．Ｔｕｌ．）Ｔｒａｐｐｅ．标本全部保存于西藏高原生态研究所标本室（ＨＸＺＥ）。     

Separation and Purification of Chongzujueside

From Hypodematium sinense lwatsuki (Thelypteridaceae) a new xanthone C-glycoside was isolated. According to chemical properties and spectroscopic (IR, UV, MS, 1H-and 13C-NMR) analysis, the structure was established as 1,3,6-trihydroxyxanthone-8-C-β-D-glucopyranoside, named chongzujueside.     

Chemotaxonomic Relationship Between Murraya and Merrillia (Rutaceae)

Swingle^[14-15] divided Aurantioideac into two tribes, one of which, Clausereae was further divided into three subtribes, namely, Micromelinae, Clauseninae and Merrilliinae. Mic romelinae and Merrilliinae each have one genus, whereas Clauseninae has three genera. Morphologically, the Clauseneae is a natural tribe, the five genera are related in a linear sequence, starting with Micromelum as the most primitive and progressing in sequence to Glycosmis, Clausena, Murraya and Merrillia. Chemical studies also support this linear relationship, as revealed by the degree of oxygenation and complexity of the 3-methyl carbazole alkaloids, from CH₃ and C1₃ in Glycosmis to CHO and C₁₈ in Clausena and COOH and C₂₃ in Murraya^[20-21]. Distribution of flavonoids also indicates the progression from Clauseninae to Merrilliinae^[18-19]. Extensive work has been conducted on the chemistry and taxonomy of the genus Murraya ^{[1,5,7-13,16]}, and the data from these studies clearly indicate the presence of two distinct groups. Based on a combination of morphological and chemical differences, we agreed with Tanaka^[16-17] in dividing Murraya into two sections, i.e. section Murraya and section Bergera^[1]. However, our previous study^[1] has not touched on the relationship between the two sections. Tanaka^[16-17] placed section Bergera before section Murraya, and indicated that the former is close to Micromelum and the latter to Merrillia. Swingle^[14-15], on the other hand, put taxa of section Murraya ahead of those of section Bergera, presumably suggesting that plants of section Murraya are more primitive than those of section Bergera, this arrangement was followed by Huang^[2-3]. The two conflicting viewpoints would have direct bearings on the interpretation of the trends of biogenesis of prenylated indole and carbazole alkaloids, as well as on the weighing of the relative advancement of the morphological characters within the genus, such as in the assignment of indices of divergence and in the construction of Wagner Divergence Diagrams. Without more objective criteria, we find it difficult to select one of the two systems. In order to determine the relationship between the two sections of Murraya, we decided to study plants of related genera, with the hope that the chemical data may shed light on the problem. A plant that attracted our attention is Merrillia caloxylon (Ridley) Swingle. So far, only eupatorin and a few other flavonoids have been reported from the fruit of this species^[4,6]. Although Me. caloxylon belongs to Merrilliinae, a subtribe next to Clauseninae, Tanaka^[16-17] believes that it is close to Murraya section Murraya. Swingle^[15], also suggested that this species might have developed from the same stock that gave rise to Mu. paniculata. If their interpretations were accurate, we would expect that Me. caloxylon would also contain yuehchukene and 8-prenylated coumarins. The presence of the antiimplantation agent would not only open up a new source of the compound but also help us judge the relationship between the two sections of Murraya. It is in this context that we studied the chemical composition of Me. caloxylon. Indeed, root and stem bark of Me. caloxylon were found to contain the antiimplantation indole alkaloid yuehchukene (1), and the 8-prenylated coumarins sibiricin (II) and phebalosin (III), as well as 3-(3-methy1-buta-1,3-diene) indole (IV) and eupatorin (V.) Details on the chemical profiles are reported in another paper. Through this exercise, we have confirmed the close relationship between Merrilliinae and Murraya section Murraya, plants of both taxa contain yuehchukene and 8-prenylated coumarins, but no carbazole alkaloid. Root and stem bark of Me. caloxylon, like those of plants of section Murraya, are strawcolored to pale whitish. Its leaves also bear wings along the rachis an in Mu. alata, and the seeds are also villous. However, Me. caloxylon has long trumpetshaped flowers 55-60 mm long, much larger than those found in other rutaceous plants. Its fruit is ob long, up to 11 cm long and 8 cm across, bearing a thick and warty pericarp, exuding a very stick mucilage when cut, and containing numerous seeds (>30). The plant was known to exist in the Malay Peninsula and north Sumatra^[15], but, according to David Jones (per. comm.) of the University of Malaya, is now only available in cultivation in Malaysia and Singapore, a limitation to any further exploitation as an additional source of yuehchukene. Besides confirming the close relationship between Merrillia and section Murraya, we may also conclude that section Bergera is close to Glycosmis and Clausena, since they are known to contain carbazole alkaloids but no yuehchukene. Accordingly, we find Tanaka’s arrangement more acceptable: plants of section Bergera are more primitive than those of section Murraya, the former is close to Clausena whereas the latter (notably Mu. alata) to Merrillia. The relationship among the gonera with in Clauseneae may be illustrated as follow: Micromelum→ Glycosmis→Clausena→Murraya sect. Bergera→Murraya sect. Murraya→Marrillia. Accordingly, we may decide that the following character states are more primitive among plants of Murraya and Merrillia: root and stem bark dark brown, leaf rachis wingless, flower small, fruit purple-black with few seeds, and seed coat glabrous. In contrast, strawcolored or pale whitish bark, winged leaf rachis, large flower, red or yellow fruit with many seeds and villous seed coat can be regarded as more advanced characters. Acknowledgments Partial support was received from the World Health Organization Special Programme on Human Reproduction and the Kevin Hsu Research Fund (to YCK) and Commonwealth Science Council (to PPHB). The staff of the Singapore Botanic Gardens and the Forest Research Institute of Malaysia are thanked for their assistance in collecting plantmaterial.     

8-Mop选育薰衣草链霉菌(Streptomyces lavendulae)的研究

本文首次报导8-甲氧基补骨脂素(8-Mop)单一选育薰衣草链霉菌(Streptomyoes lavendulae)的研究结果,曾有摇瓶发酵单位提高18．3％的高产株获得,高产株已在国内应用。     

肾上腺髓质素降低培养海马神经元胞内游离钙离子浓度

经荧光探针Fluo 3-AM标记细胞内游离钙后,用激光共聚焦显微镜检测肾上腺髓质素(adrenomedullin,ADM)对原代培养大鼠海马神经元内游离钙浓度([Ca^2 ]1)的影响。实验结果如下：(1)ADM(0．01-1．0μmol／L)浓度依赖性地降低细胞内钙浓度。(2)降钙素基因相关肽受体阻断剂(calcitonin gene-related peptide,CGRP8-37)预处理可部分抑制ADM的效应。(3)ADM可显著抑制高钾引起的[Ca^2 ]1增加。(4)ADM可显著抑制三磷酸肌醇(inositol 1,4,5-trisphosphate,IP3)引起的内钙释放,而对兰尼定(ryanodine)引起的内钙释放无显著影响。以上结果提示,ADM降低培养海马神经元内游离钙浓度,此作用与其抑制IP,引起的内钙释放有关,ADM对静息状态下的Ca^2 内流无影响,但可显著抑制高钾引起的Ca^2 内流,CGRP受体介导了ADM的上述效应。     

桉叶素生物合成研究进展

作为桉叶油的主要成分,桉叶素是具有多种生物活性的单萜化合物,被广泛应用于药品、食品及化妆品等领域。桉叶油主要从桉树叶提取,该过程耗费大量人力及自然资源,且容易污染环境。近年来,随着微生物代谢工程与合成生物学的快速发展,加上越来越多萜类生物合成途径得到解析,为桉叶素的绿色生产提供了新的途径。对桉叶素的生物合成途径、桉叶素合酶的结构与功能及近年来桉叶素的微生物合成进行了综述,并对利用微生物代谢工程合成桉叶素等单萜化合物的瓶颈问题及解决方案进行了探讨和归纳,为构建高产桉叶素等单萜微生物工程菌株提供参考。     

Aspergillus sp. EA-LJS80的分离及其发酵液提取物七叶皂苷C的生物活性

本研究从陕西留坝紫柏山采集的七叶树Aesculus chinensis根和茎中分离出一株具有高产七叶皂苷C的内生真菌,将其编号为EA-LJS80。利用ITS序列分析鉴定其种属并对其形态进行观察;采用紫外-可见分光光度计进行全波长扫描,确定其最大紫外吸收峰;采用HPLC测定七叶皂苷C的产量;采用滤纸片扩散法研究其发酵液提取物的抑菌活性;采用CCK-8法测定提纯后七叶皂苷对肺腺癌A₅₄₉细胞的增殖抑制率,探究其生物活性。结果显示,该菌株EA-LJS80为曲霉菌属Aspergillus真菌,最大紫外吸收波长为230nm,测得提纯后七叶皂苷C的产量为9.23mg/mL。生物活性实验表明：菌株EA-LJS80的发酵液提取物对大肠杆菌Escherichia coli等4种致病菌有明显的抑菌效果;经CCK-8法测定,提纯后的七叶皂苷对肺腺癌A₅₄₉细胞的增殖有明显的抑制作用。综上所述,菌株EA-LJS80具有产七叶皂苷活性,尤其是七叶皂苷C的产量较高,且其产生的七叶皂苷具有较高的生物活性,这对于改进七叶皂苷生产模式,提高生产效率具有重要意义,同时对于七叶皂苷C的进一步研究有一定的促进作用。