木通科植物的化学分类

木通科为双子叶植物纲中较原始的一个小科,多为寡种属和单种属,主要分布于东亚地区。我国共有7属29种,其中很多种为传统的药用植物。本文简要综述木通科植物近几十年的化学研究状况,并从化学分类学的角度探讨木通科属间和与其近缘科之间的系统关系。结果表明齐墩果烷型三萜皂甙作为木通科的特征化学成分在该科的系统分类中具有一定的意义。齐墩果烷型三萜皂甙不仅提示木通科与毛茛科的毛茛亚科的系统联系,而且甙元骨架的氧化水平与科内各属的系统进化也有一定的相关性。     

金铁锁皂甙的研究

从金铁锁(Psammoslene tunicoides)根中分离到二个新的齐墩果烷型五环三萜皂甙Ⅰ、Ⅱ,经光谱测定和化学降解证明它们的化学结构为齐墩果烷-3α,16α-二羟基-12烯-23-酸-28-O-β-D-葡萄吡喃糖基(1—3)-β-D-葡萄吡喃糖基(1—6)-β-D-葡萄吡喃糖甙(Ⅰ)和齐墩果烷-3α,16α-二羟基-12烯-23-酸-28-O-β-D-葡萄吡喃糖基1—6[-β-D-葡萄吡喃糖基1—3]-β-D-葡萄吡喃糖甙(Ⅱ)。上述两个化合物的母核配基均为同一的物质,差异是糖的连接位置不相同。     

木通科植物的化学分类

木能科为双子叶植物纲中较原始的一个小科,多为寡种属和单种属,主要分布于东亚地区。我国共有7属29种,其中很多种为传统的药用植物。本文简要综述木通科植物近几十年的化学研究状况,并从化学分类学 的角度探讨木通科属间和与其近缘科之间的系统关系。结果表明齐墩果烷型三匝皂甙作为木通科的特征化不成发在该科的系统分类中具有一定的意义。齐墩果烷型三萜皂甙不仅提示木通科与毛莨科的毛莨亚科的系统联系,而且甙元骨架的氧化水平与科内各属的系统进货也有一定的相关性。     

葫芦科植物三萜皂甙研究十年进展（1980—1992）

综述了２９８０年至１９９２年以来葫芦科盒子草属,土贝母属Ｃａｙａｐｏｎｉａ属,南瓜属,Ｆｅｖｉｌｌｅａ属,纹股蓝属,雪胆属,丝瓜属,苦瓜属,棒锤瓜属,罗汉果属,赤ｂａｏ属,Ｗｉｌｂｒａｄｉａ等１３属２４种植物２００多个三萜类新化合物的研究概况。其中值得注意的是五环三匝齐墩果烷型大环皂甙,四环三萜葫芦烷型甜味甙,非葫芦烷型三萜皂甙,达玛烷型皂甙和巴查烷型三萜皂甙的发现。文末附参考文献８３篇。     

茯苓中三萜类和多糖类成分的研究进展

主要对中药茯苓中的三萜类和多糖类成分进行了综述。到目前为止已从茯苓的菌核和菌丝中分离到三萜类物质39个,其中羊毛甾-8-烯型三萜12个,羊毛甾-7,9(11)-二烯型三萜16个,3,4-开环-羊毛甾-7,9(11)-二烯型三萜7个,3,4-开环-羊毛甾-8-烯型三萜2个,三环二萜类1个,齐墩果烷型三萜1个;分离到多糖类物质23个。     

百两金皂苷类似物的化学与药理学研究进展

对百两金皂苷类似物的化学和药理活性进行文献综述。迄今报道的百两金皂苷类似物大约有60个,其齐墩果烷三萜母核上具有多种与生物活性有关的特征取代基,包括13β,28-环醚、30-氧化甲基和3-O-糖链等。该类物质多具抗肿瘤、抗炎和抗真菌等药理活性,值得深入研究。     

鱼藤的三个新三萜化合物

从民间杀虫植物鱼藤（Derris eriocarpa How)的根中分离得到5个三萜化合物,经波谱和化学分析确定了这些化合物的化学结构,其中化合物1（3β,15α-dihydroxy-olean-12(13)-en-16-one),2(3β,15α,23-trihydroxy-olean-12(13)en-16-one),3(15α-hydroxyl-16-oxo-olean-12(13)-en-3-O-β-glucuronopyranoside)为新化合物,命名为鱼藤三萜素A,B,C。两个已知三萜为2β,3β,28-三羟基-12（13）-烯-齐墩果烷和β-香树脂素（β-amyrin)。另外还得到了二十七碳脂肪酸单甘油酯和β-谷甾醇。     

一些天然产齐墩果烷型三萜化合物的~(13)C核磁共振谱

齐墩果烷型三萜是一类比较广布的化学成分,常以配糖体的形式存在于植物体中,有的并已证明具有种种的生理活性。近年,~(13)C核磁共振谱已逐渐成为这类化合物结构测定的重要手段。本文报告用26.23兆赫WH-90FT核磁共振波谱仪测定12个天然产齐墩果烷型三萜化合物的~(13)C核磁共振谱,对各碳的化学位移进行了指定,并试图讨论这些化合物的共振讯号与化学结构之间的相互关系。     

黄花远志的新齐墩果烷型三萜皂甙

从云南产远志科药用植物黄花远志(PolygalaarillataBuchHamexDDon)茎皮的乙醇提取物中分离得到4个新的齐墩果烷型三萜皂甙,命名为黄花远志皂甙(arillatanoside)A～D。同时还分离得到1个已知的三萜皂甙远志甙(polygalasaponin)XXXV。它们的结构通过波谱方法推定。     

苦丁茶甙元Ⅰ的结构鉴定

从苦丁茶（IlexkndinchaCJTseng）叶中分离到一新的三萜甙元,命名为苦丁茶甙元Ⅰ。经化学、波谱分析及单晶X-射线衍射研究,确定其结构为3β-羟基-11（12）,13（18）,19（29）-三烯-28,20β-内酯乌苏烷。     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

On the Dependence of the Quadratic Risk of the Classical Predictor and the Prediction-Horizon

When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.     

中国植物区系与其它地区区系的联系及其在世界区系中的地位和作用

基于吴征镒将中国全部种子植物３２３８个属的分布区划分为１５个大类型和３４个变型的基础上,简要地讨论了中国植物区系与其它地区区系的联系,以及它在被子植物起源方面的作用。主要论点如下：（１）与热带亚洲区系的联系。这种联系主要通过第７类型（热带亚洲分布）及其５个变型来体现的。本文列举了１０个科,龙脑香料、狭义隐翼科、交让木科、五隔草科、五列木科、肉实树科、心翼果科、八宝树科、兰花蕉科和四数木科,来说明这