舞花姜花部维管束系统的解剖学研究

对舞花姜(Globba racemosa)花部维管束系统进行解剖学观察分析,以探讨其缺失雄蕊的去向及其唇瓣和腺体结构的属性.结果显示:(1)舞花姜花梗部的维管束分散排列在基本组织内.(2)子房基部的维管束排成2部分,中央区为分散排列的小维管束,外方为一轮大维管束环,且外环维管束发育为子房壁维管束,心皮背束和隔膜束均起源于中心区维管束,二者的分支在延长部形成一个维管束网结;在网结之上,近轴面的两束心皮背束分支分别进入到2枚侧生退化雄蕊中并成为其主束,远轴面心皮背束的内方分支则成为唇瓣中束,三束心皮背束的其余分支均上行入萼片.(3)唯一1枚功能雄蕊接受近轴面隔膜束的内方主支作为其主束,远轴面2枚隔膜束的主支最后进入唇瓣的两侧束,三束隔膜束的外分支均发育为花瓣束.研究认为:舞花姜的唇瓣是一个三重结构,其中央维管束代表1枚外轮雄蕊,两侧维管束则分别代表2枚内轮雄蕊;舞花姜的2枚花瓣状退化雄蕊与唇瓣的中央一起构成外轮雄蕊,唯一1枚可育雄蕊和唇瓣的两侧同属内轮雄蕊.本研究结果支持姜科子房延长部形成的腺体属于子房上部心皮边缘的维管化附属物的观点.     

红蕉花部维管束系统的解剖学研究

红蕉花单性、同株 ,雄花与雌花花梗部的维管束均可分为外环维管束、中环维管束及中央维管束区。雌花外环维管束逐渐外移 ,并分支、变小、数目增多 ,至子房室区中部时几乎贴近表皮 ;中环维管束与外环维管束形态基本相似、稍大 ,至延长部中上部时与外环维管束合成一轮 ,最后进入花被片 ,成为花被维管束系统 ;中央维管束区在花梗部时排列为六组 ,组间有一些小的维管束分布。在室下区 ,近轴面隔膜维管束组消失 ,至子房室区基部时 (室下区 )其它五组逐渐聚集成明显五束 ;而组间的小维管束向中央聚拢 ,于子房室区基部时排列成环形 ,接着进入子房室中轴成为胎座维管束 ,随后束形变小 ,且随子房室的变小而外移 ,经延长部最后进入花柱 ,与心皮背束内方的三枚分支一起成为花柱维管束系统。三束心皮背束延伸至延长部时均分裂为内、外两支 ,三枚外方的分支进入三枚外轮雄蕊。两束远轴面隔膜束进入两枚内轮雄蕊。雄花与雌花的维管束系统基本相似 ,差异主要在雄花无子房室区及中轴的胎座维管束消失。     

兰花蕉花部维管束系统的解剖学研究

兰花蕉花梗的维管束分散排列．子房基部的维管束排成两部分,外方为一轮大维管束环,中央为分散排列的小维管束区。前者的纸管束进入子房壁,后者进入子房的中轴,形成股座纸管束;及至延长都以后,股座维管束逐渐消失．子房壁上的维管束较易识别的有心皮背束、心皮背束伴束和隔膜束．三束心皮背束经延长部最终进入花柱和柱头．心皮背束指心皮背束务与其紧靠的大维管束,三枚心皮背束伴束最终分别进入三枚外轮雄蓝．三枚隔膜束中远轴面的两枚分别进入两校内轮雄蕊,而近轴面的一枚伴随着第六枚雄蓝的缺失最后进入唇瓣中央．子房壁其余的维管束进入延长部后,先向外分出一轮纸管束进入花幕,余下的中央部分排成一轮心形的线管来环．该环远轴面的维管束分为两半分别进入两枚侧生花瓣;近轴面即心形凹陷一侧初为两轮即外轮大的维管束与内轮小的维管束,后排成一轮并与近轴面的隔膜束一同进入唇瓣．兰花蕉的唇瓣既为花瓣成员,又含一枚缺失的雄蓝维管束,与姜目已报道的只来自退化雄蕊的竹芋科的兜状结构和美人蕉科、姜科、闭鞘姜科的唇瓣有明显区别．在旅人蕉科尚未有研究资料的情况下,作者根据已有资料,对姜目雄蕊维管束系统来源和结构进行比较,初步认为在姜目的系统演化上,兰花蕉科与芭蕉料更近．     

姜花(Hedychium coronarium)花部维管束系统解剖学研究

姜花(Hedychium coronarium Koen.)花梗横切面整体轮廓呈椭圆形,可分为表皮、基本组织和维管束。维管束在基本组织中呈内、外两部分排列。内部维管束联结成网,形成明显外移的三束心皮背束和内方与心皮背束相间的三束隔膜束。至子房室区,心皮背束继续外移,其中主支进入花萼中脉;小分支内移,与内方一轮维管束联结,后来进入唇瓣中央及2枚侧生附属物。在花萼形成的同时,远轴面的两个隔膜中各形成一个上位腺体;同时两束远轴面隔膜束向外、两侧分别形成3束大分支,外方大分支继续外移成为2枚远轴面花瓣中脉,两侧大分支与原外方内移的子房壁维管束集合成一相连的环状维管束网,后进入唇瓣两侧;近轴面隔膜束形成3枚分支,外方分支成为近轴面花瓣中脉,两侧分支进入可育雄蕊。探讨了侧生附属物和唇瓣的来源,支持子房延长部形成的腺体为隔膜蜜腺的变异结构的观点。     

粉美人蕉花部维管束的解剖学研究

为探讨粉美人蕉(Canna glauca‘Erebus’)缺失雄蕊的去向和唇瓣的属性,对粉美人蕉花部维管束系统进行了解剖学观察分析。结果表明,粉美人蕉花梗横切面呈椭圆形,中心区的维管束聚集成6束大的维管束,形成心皮背束和隔膜束。在子房区顶部,3个隔膜束各分成3束,外方分支分别进入相应的花瓣,成为花瓣的中束。近轴面隔膜束内方的2束分支进入功能雄蕊。远轴面右侧的隔膜束内方2分支进入唇瓣,发育为唇瓣的部分维管束。远轴面左侧隔膜束内方分支进入内轮退化雄蕊。在花瓣形成时,近轴面左侧心皮背束分成2束,外侧分支进入近轴面外轮退化雄蕊,内侧分支进入功能雄蕊。近轴面右侧心皮背束外方分支进入侧生退化雄蕊。远轴面心皮背束分为2束,1束进入远轴面外轮退化雄蕊并迅速消失,另1束进入唇瓣,继续发育。从维管束来源角度证明了粉美人蕉退化雄蕊的同源异形现象。     

兰花蕉花的形态解剖学

兰花蕉（Orchidantha chinensis)的子房室顶部闭合后向上延长成延长部,实心,但有花柱沟和隔膜蜜腺管通过,隔膜蜜腺管,可分为中央蜜腺管和三条侧蜜腺管;中央蜜腺管位于三个心皮连接处,自子房室区下部产生,向上于延长部的部顶端终止;三条侧管分别位于两个心皮连接处,于子房室区近中部产生,开口于花柱基部。兰花蕉子房室区与延长部均具6枚雄蕊的维管束系统,即3枚心皮背束的伴束与3枚隔膜束,近轴面1枚事膜向上进入唇瓣的维管束系统,位于唇瓣的中央,致使兰花蕉仅具5枚功能雄蕊,唇瓣具双重结构,本文还讨论了兰花蕉科的系统发育位置。     

金嘴蝎尾蕉花部维管束系统的解剖学研究

利用石蜡切片技术对蝎尾蕉科代表植物金嘴蝎尾蕉（Heliconia rostrata Ruiz＆Pavon）的花部维管束系统进行了解剖学研究。结果表明,心皮背束在延长部的基部分裂为内外2分支,内方分支与胎座维管束汇合后进入花柱,远轴面2枚外方分支在延长部的顶部分裂为2～4束进入远轴面2枚外轮雄蕊,而近轴面1枚外方分支则进入退化结构成为其中脉;隔膜束在延长部顶部亦分裂为3～5束,最终分别进入3枚内轮雄蕊;子房壁其它维管束最终进入花被片。本研究认为金嘴蝎尾蕉花部花瓣状退化结构与另外2枚外轮雄蕊具有完全相同的维管束系统来源,应属于雄蕊成员,且支持Kress关于蝎尾蕉科是姜群的姊妹群,区别于芭蕉群其它3科的观点。     

鸭跖草花部维管束系统解剖学研究

鸭跖草花梗项部的维管束分布在中央的基本组织内。自花梗顶部至子永恒基部,维管束系统发生复杂的变化。6枚向外偏斜的维管束发生内外或左右分支,其中3枚维管束发生内外分支,其外侧的3个分支进入萼片成为萼片给管束系统,内侧3个分支进入3枚外轮雄蕊而成为外轮雄蕊维管束;另3枚维管束先发生内外分支,接着外侧3分支发生进一步的左右分支,各形成3－5个小分支,最后进入花瓣成为花瓣维管束系统,而内侧的分支则不再细分,最后伸入3枚内轮雄蕊,成为轮雄蕊维管束。另6枚近圆束形的维管束一直在中央向上延伸,进入子房屋区后,其中3格言 进入子房壁,成为3束心皮背束,最后3束心皮背束进入花柱成为花柱维管史,另3枚聚向中央,成为胎座维管束,胎座维管束至子房屋顶部时消失。文中对跖草及其有关类群的花部维管束系统的来源及演变进行了比较、讨论。     

大鹤望兰花部维管束系统的解剖学研究

大鹤望兰梗横切面近三角形,花梗的维管束分散公布在基本组织内。室下区的维管束大致排列三两部分,外方为一到两环维管束组成的外维管束环,中央为分散排列的中央维管束区。前者的维管束进入子房避讳,后者的维管束进入子房的中轴,形成从维管束。至延长部后,胎座维管束逐渐消失。子房壁上的维管束较易识别的有心皮背束、心成背束伴束和隔膜束。３束心皮背束经处长部最终进入花柱。３枚心皮背束伴束最终分别进入一枚１２上轮雄蕊。     

圆瓣姜花花部维管束解剖及其系统学意义

用石蜡切片技术研究了圆瓣姜花(Hedychium forrestii Diels)的花部维管束系统解剖结构,探讨了同源异形的各轮花器官维管束来源和属性.结果表明,圆瓣姜花的2枚花瓣状结构为外轮雄蕊成员;唇瓣是三重结构,其中脉源十1枚外轮雄蕊维管束系统,两侧脉源于2枚内轮雄蕊维管束系统;上位腺体为隔膜蜜腺.本研究支持Thompson和Gregory关于姜科唇瓣是三重结构的观点;与其他姜科植物一样,圆瓣姜花子房延长部形成的上位腺体属于隔膜蜜腺而不是雄蕊成员.与已研究过的姜花属植物比较,姜花属花器官维管束系统的来源与走向是一致的,同源异形现象在姜花属植物花的进化中扮演极为重要的角色,可为解释花器官属性提供重要线索.     

Ecology of Thioploca spp.: nitrate and sulfur storage in relation to chemical microgradients and influence of Thioploca spp. on the sedimentary nitrogen cycle.

Microsensors, including a recently developed NO3(-) biosensor, were applied to measure O(2) and NO3(-) profiles in marine sediments from the upwelling area off central Chile and to investigate the influence of Thioploca spp. on the sedimentary nitrogen metabolism. The studies were performed in undisturbed sediment cores incubated in a small laboratory flume to simulate the environmental conditions of low O(2), high NO3(-), and bottom water current. On addition of NO3(-) and NO2(-), Thioploca spp. exhibited positive chemotaxis and stretched out of the sediment into the flume water. In a core densely populated with Thioploca, the penetration depth of NO3(-) was only 0.5 mm and a sharp maximum of NO3(-) uptake was observed 0.5 mm above the sediment surface. In sediments with only few Thioploca spp., NO3(-) was detectable down to a depth of 2 mm and the maximum consumption rates were observed within the sediment. No chemotaxis toward nitrous oxide (N2O) was observed, which is consistent with the observation that Thioploca does not denitrify but reduces intracellular NO3(-) to NH(4)(+). Measurements of the intracellular NO3(-) and S(0) pools in Thioploca filaments from various depths in the sediment gave insights into possible differences in the migration behavior between the different species. Living filaments containing significant amounts of intracellular NO3(-) were found to a depth of at least 13 cm, providing final proof for the vertical shuttling of Thioploca spp. and nitrate transport into the sediment.     

Stereochemistry of a methyl-group rearrangement during the biosynthesis of lanosterol.

1. (3RS,6R)-[6-2H1,6-3H1,6-14C], (3RS,6S)-[6-2H1,6-3H1,6-14C] and (3RS)-[6-3H1,6-14C]mevalonolactones were synthesised from R-[2H1,3H1,2-14C], S-[2H1,3H1,2-14C] and [3h1,2-14C]acetic acids respectively. 2. Each mevalonate was converted into cholesterol by a rat liver preparation. 3. Each cholesterol specimen was converted into androsta-1,4-diene-3,17-dione by incubation with Mycobacterium phlei in the presence of 2,2'.dipyridyl. Each specimen of androsta-1,4-diene-3,17-dione was converted into androsta-1,4-dien-3-one-17-ethylene ketail. 4. The samples of androsta-1,4-dien-3-one-17-ethylene ketal were each converted chemically into oestrones in which the methyl group at C-18 is the only carbon atom that originated from C-6 in mevalonolactone. 5. The oestrone from (3RS)-[6-3H1,6-14C]mevalonolactone was oxidised chemically to acetic acid which was converted into p-bromophenacyl acetate and the 3H/14C ratio was measured. 6. There was no overall loss of tritium from the methyl group of acetic acid, as measured by determining the 3H/14C ratios of the p-bromophenacyl esters, when the synthetic and degradative procedures 1 -- 5 were tested with [3H1,2-14C]acetic acid. 7. The oestrones derived from the 6R and 6S-mevalonolactones were oxidised. The chiralities of the resulting acetates were determined by an established procedure whereby the acetates were converted into 2S-malates which were examined for loss of tritium on equilibration with fumarate hydratase. 8. The oestrone from (3RS,6R)-[6-2H1,6-3H1,6-14C]mevalonate gave acetic acid which was converted into 2S-malate that retained 68.6% of its tritium after treatment with fumarate hydratase; the configuration of this acetic acid was R. 9. The oestrone from (3RS,6S)-E16-2H1,6-3H1,6-14C]mevalonate was oxidised to acetic acid which was converted into 2S-malate that retained 31.9% of its tritium after treatment with fumarate hydratase; the configuration of this acetic acid was S. 10. There was no overall change in the configuration of a chiral methyl group between C-6 of mevalonate and C-18 of oestrone. It is cncluded that the intramolecular migration of a chiral methyl group from C-15 in 2,3-oxidosqualene to C-13 in lanosterol is stereospecific and occurs with overall retention of configuration.     

13-cis retinoic acid and all-trans retinoic acid in the regulation of the proliferation and survival of human breast cancer cell line MCF-7.

Retinoids are a group of compounds which inhibit cell proliferation and induce cellular differentiation. The aim of this study was to compare the antiproliferative activity of various concentrations of 13-cis retinoic acid (isotretinoin) and all-trans retinoic acid (tretinoin) in a culture of the estrogen-sensitive human breast cancer cell line MCF-7. Evaluation was based on [3H]thymidine incorporation into the cancer cells and through immunocytochemical analysis of cell cycle-associated PCNA and Ki-67 protein expression. Both retinoids inhibited [3H]thymidine incorporation into the cancer cells most effectively at a concentration of 3x10(-3) M. Two basic substances used for line MCF-7 culture experiments, one stimulating - estradiol - and the other inhibiting - tamoxifen - were applied. Estradiol added to a culture containing decreasing concentrations of isotretinoin (from 3x10(-3) to 3x10(-8) M) caused a statistically significant reduction in the percentage of [3H]thymidine incorporation into the cancer cell line MCF-7, compared to the 17 beta estradiol group (189.25%+/-62.64, control=100%, p<0.05). In the group of decreasing tretinoin concentrations, statistically significant differences were found only at 3x10(-3), 3x10(-4) and 3x10(-8) M. Following culture supplementation with tamoxifen (1 microM), statistically significant differences were observed only at the highest concentrations of both retinoids (3x10(-3) and 3x10(-4) M). The evaluation of breast carcinoma cells with a positive immunocytochemical reaction to PCNA and Ki-67 has revealed that isotretinoin reduces their percentage in the most determined and statistically significant way (38.00%+/-2.58 and 39.25%+/-3.09), compared to the control group (86.50%+/-9.20 and 100%+/-3.87, p<0.001 and p<0.0001) and to the estradiol group (87.00%+/-6.79 and 86.10%+/-7.0, p<0.001). Apart from their blocking effect on the cell cycle, retinoids also induce the apoptotic pathway.     

Metabolism of long-chain polyunsaturated fatty acids in isolated cardiac myocytes

The uptake and integrated intracellular metabolism of (n - 6) and (n - 3) polyunsaturated fatty acids was studied in isolated rat cardiac myocytes and in the perfused heart. Labeled linolenic acid (18:3(n - 3)) uptake and its subsequent metabolism into carbon dioxide as well as acylation into lipids was nonsaturable over a substrate range of 0.02 to 0.4 mM. [1-14C]Linoleic acid (18:2(n - 6)), dihomo-gamma-linolenic acid (20:3(n - 6)) and arachidonic acid (20:4(n - 6)) were transported into myocytes at rates similar to those for linolenic acid. Conversely both [1-14C]-gamma-linolenic acid (18:3(n - 6)) and eicosapentaenoic acid (20:5(n - 3)) were taken up at a slower rate. Oxidation of 18:3(n - 6) was 4-5-fold greater when compared with C18-C20 polyunsaturated fatty acids. When myocytes were incubated with labeled 18:2(n - 6), 18:3(n - 6), 18:3(n - 3), 20:4(n - 6) or 20:5(n - 3), it was not possible to detect any desaturation or chain-elongation products. Identical results were obtained when hearts were perfused with 1-14C-labeled linoleic acid.     

Metabolism of 1alpha,25-dihydroxyvitamin D(3) and its C-3 epimer 1alpha,25-dihydroxy-3-epi-vitamin D(3) in neonatal human keratinocytes

We previously reported that 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] is metabolized into 1alpha,25-dihydroxy-3-epi-vitamin D(3) [1alpha,25(OH)(2)-3-epi-D(3)] in primary cultures of neonatal human keratinocytes. We now report that 1alpha,25(OH)(2)-3-epi-D(3) itself is further metabolized in human keratinocytes into several polar metabolites. One of the polar metabolite was unequivocally identified as 1alpha,23,25-trihydroxy-3-epi-vitamin D(3) by mass spectrometry and its sensitivity to sodium periodate. Three of the polar metabolites were identified as 1alpha,24,25-trihydroxy-3-epi-vitamin D(3), 1alpha,25-dihydroxy-24-oxo-3-epi-vitamin D(3) and 1alpha,23,25-trihydroxy-24-oxo-3-epi-vitamin D(3) by comigration with authentic standards on both straight and reverse phase HPLC systems. In addition to the polar metabolites, 1alpha,25(OH)(2)-3-epi-D(3) was also metabolized into two less polar metabolites. A possible structure of either 1alphaOH-3-epi-D(3)-20,25-cyclic ether or 1alphaOH-3-epi-D(3)-24,25-epoxide was assigned to one of the less polar metabolites through mass spectrometry. Thus, we indicate for the first time that 1alpha,25(OH)(2)-3-epi-D(3) is metabolized in neonatal human keratinocytes not only via the same C-24 and C-23 oxidation pathways like its parent, 1alpha,25(OH)(2)D(3); but also is metabolized into a less polar metabolite via a pathway that is unique to 1alpha,25(OH)(2)-3-epi-D(3).     

Is the retrograde axonal transport of 3H-5-HT a specific process of serotoninergic neurons?

The specificity of the retrograde axonal transport of 3H-serotonin (3H-5-HT) was radioautographically studied in the afferents to the olfactory bulb (O.B.). Injections of 3H-5-HT of different concentrations (10(-2), 10(-3), 10(-4) and 10(-5) M) were performed into the O.B. of catron pretreated rats. Following injection of 3H-5-HT (10(-2) M), a cytoplasmic perikaryal labeling was observed in the bulk of afferents to the O.B. (aminergic and non-aminergic neurons). When lower concentrations of 3H-5-HT (10(-5) M) were injected into the O.B., the retrograde labeling was only seen in the raphe dorsalis (RD) serotoninergic perikarya. The specificity of the uptake-retrograde transport of 3H-5-HT seems to depend on the selectivity of uptake by nerve terminals.     

人sTNFR1基因的克隆以及在NIH3T3细胞中的稳定表达

以He1a细胞的总RNA为模板,用RT—PCR方法扩增sTNFR1全编码区基因片段,构建含有目的片段的T载体克隆及真核表达载体pcDNA3．1（-）重组质粒亚克隆,将重组质粒和脂质体共同转染NIH3T3细胞系,G418筛选稳定转染细胞株．经核苷酸序列测序和酶切鉴定,成功构建了pcDNA3．1（-）-sTNFR1真核表达质粒,脂质体法建立了高效表达sTNFRI的稳定转染细胞系,并经RT—PCR和Western Blotting鉴定．人sTNFR1基因能在NIH3T3细胞系中稳定表达,为今后的研究打下了基础．     

Biosynthesis of methanopterin

The biosynthetic pathway for the generation of the methylated pterin in methanopterins was determined for the methanogenic bacteria Methanococcus volta and Methanobacterium formicicum. Extracts of M. volta were found to readily cleave L-7,8-dihydroneopterin to 7,8-dihydro-6-(hydroxymethyl)pterin, which was confirmed to be a precursor of the pterin portion of the methanopterin. [methylene-2H]-6-(Hydroxymethyl)pterin was incorporated into methanopterin by growing cells of M. volta to an extent of 30%. Both the C-11 and C-12 methyl groups of methanopterin originate from [methyl-2H3]methionine, as confirmed by the incorporation of two C2H3 groups into 6-ethyl-7-methylpterin, a pterin-containing fragment derived from methanopterin. Cells grown in the presence of [methylene-2H]-6-(hydroxymethyl)pterin, [ethyl-2H4]-6-[1 (RS)-hydroxyethyl]pterin, [methyl-2H3]-6- (hydroxymethyl)-7-methylpterin, [ethyl-2H4, methyl-2H3]-6-[1 (RS)-hydroxyethyl]-7-methylpterin, and [1-ethyl-3H]-6-[1 (RS)-hydroxyethyl]-7-methylpterin showed that only the non-7-methylated pterins were incorporated into methanopterin. Cells extracts of M. formicicum readily condensed synthetic [methylene-3H]-7,8-H2-6-(hydroxymethyl)pterin-PP with methaniline to generate demethylated methanopterin, which is then methylated to methanopterin by the cell extract in the presence of S-adenosylmethionine. These observations indicate that the pterin portion of methanopterin is biosynthetically derived from 7,8-H2-6-(hydroxymethyl)pterin, which is coupled to methaniline by a pathway analogous to the biosynthesis of folic acid. This pathway for the biosynthesis of methanopterin represents the first example of the modification of the specificity of a coenzyme through a methylation reaction.     

酒色着色菌内膜系统光依赖性同化亚硒酸钠为硒半胱氨酸的研究

分离的酒色着色菌（Ｃｈｒｏｍａｔｉｕｍｖｉｎｏｓｕｍ）内膜系统在光照和Ｏ乙酰丝氨酸（ＯＡＳ）存在的条件下,能以３５９纳摩尔／毫克细菌叶绿素·小时（ｎｍｏｌ·ｍｇＢｃｈｌ－１·ｈ－１）的速度催化ＳｅＯ２－３合成硒半胱氨酸。用超声波处理的内膜系统,催化速度仅为处理前的１１％,加入谷胱甘肽（ＧＳＨ）和还原型辅型Ⅱ（ＮＡＤＰＨ）后,其速度增加至处理前的８８３％,该反应对光具有依赖性,进一步实验表明,纯化的谷胱甘肽还原酶,在有半胱氨合酶、ＯＡＳ和ＮＡＤＰＨ共存时,能催化ＳｅＯ２－３转化为硒半胱氨酸,表明ＳｅＯ２－３在内膜系统中能被光偶联的谷胱甘肽还原酶还原为Ｓｅ２－,然后经半胱氨酸合酶的催化作用转化为硒半胱氨酸