用氨基酸分析仪测定茶氨酸

茶氨酸是茶中主要的和特有的氨基酸。除山茶、茶梅等茶科植物外,至今尚未在其它植物中检出。茶叶中茶氨酸的含量甚高,约占游离氨基酸总量的50—70％,直接影响茶树的新陈代谢和茶叶品质。绿茶茶氨酸含量与滋味等级呈正相关,红茶汤味也受茶氨酸     

茶氨酸的制取及应用

茶氨酸是茶叶中的一种主要氨基酸 ,通常占茶叶干重的 2 %左右 ,约占茶树体内游离氨基酸5 0 %。茶氨酸具有鲜甜味 ,是茶叶特征物质之一 ,与茶叶品质呈正相关。现已作为食品添加剂应用于食品领域。除此以外 ,茶氨酸还具有一些重要的药理作用。如抗肿瘤、降压安神、拮抗咖啡碱等医疗功效。本文综述了茶氨酸的性质、制取方法及应用前景等方面的内容。     

茶氨酸保健功能研究进展

茶氨酸是茶叶中特有的氨基酸,是茶叶重要活性成分之一。国内外大量研究表明它在保护神经、镇静、调节情绪、提高认知能力等方面有良好的保健作用。最新的研究进展表明茶氨酸可以通过激活T淋巴细胞起到抗肿瘤的作用。作为保健品,茶氨酸在医药和食品加工方面也有着良好的应用前景。     

不同培养条件对悬浮培养茶叶细胞生长及茶氨酸合成的影响*

婺源绿茶嫩叶用MS 培养基( 加IBA 2 mgPL, 6-BA 4 mgPL) 进行茶叶愈伤组织悬浮培养, 研究了不同培养条件对茶叶细胞悬浮培养过程中细胞生长与茶氨酸合成的影响。结果显示, NH4+PNO3- 110P6010 mmolPL、K+ 10010 mmolPL、Mg2+ 310mmolPL、H2PO4- 310 mmolPL、蔗糖3010 gPL、水解酪蛋白210 gPL 条件下, 茶叶细胞生长量和茶氨酸积累量均达到最高值; 提高培养基中蔗糖和水解酪蛋白浓度可使细胞对数生长期和稳定期得到延长, 从而有利于茶氨酸积累; H2 PO4- 浓度主要影响细胞生长速率和茶氨酸积累速率的同步性, 低H2 PO4- 浓度环境中茶氨酸积累速率峰值滞后于细胞增长速率峰值, 高H2PO4- 浓度环境中早于细胞生长速率峰值出现时间; K+ 和Mg2+ 对细胞生长的影响不明显, 但影响细胞茶氨酸合成酶活性, 维持适量的K+和Mg2+ 有利于茶氨酸积累。添加盐酸乙胺可大幅度提高茶氨酸积累量, 并且先加入一定量盐酸乙胺再每天进行少量补充, 茶氨酸合成量比一次性加入的效果要好。茶叶细胞生长和茶氨酸积累高峰期在整个培养过程的第19~ 22 天出现, 从生产效率考虑, 培养周期以19~ 22 天为宜。     

大规模茶叶细胞悬浮培养茶氨酸合成工艺优化研究

以婺源绿茶为材料进行茶叶愈伤组织悬浮培养,采用正交实验设计进行了大规模茶叶细胞悬浮培养合成茶氨酸工艺条件优化研究。结果显示,NH4+/NO-30.0/60.0mmol/L、K+100.0mmol/L、Mg++3.0mmol/L、H2PO-43.0mmol/L、蔗糖30.0g/L、水解酪蛋白2.0g/L条件下,茶叶细胞生长量(速率)和茶氨酸积累量均达到最高值;提高培养基中蔗糖和水解酪蛋白浓度可延长细胞对数生长期和稳定生长期,从而有利于茶氨酸积累;H2PO-4浓度主要影响细胞生长速率和茶氨酸积累速率的同步性,低H2PO4-浓度环境中茶氨酸积累速率峰值滞后于细胞增长速率峰值,高H2PO4-浓度环境中早于细胞生长速率峰值出现时间;K+和Mg++对细胞生长的影响不明显,但影响茶氨酸合成酶活性,维持适量的K+和Mg++有利于茶氨酸积累。先加入一定量盐酸乙胺再每天进行少量补充,茶氨酸合成量比一次性加入的效果要好。从生产效率考虑,培养周期以19～22d为宜。     

不同培养条件对悬浮培养茶叶细胞生长及茶氨酸合成的影响

婺源绿茶嫩叶用MS培养基（加IBA 2mg／L,6-BA 4mg／L）进行茶叶愈伤组织悬浮培养,研究了不同培养条件对茶叶细胞悬浮培养过程中细胞生长与茶氨酸合成的影响。结果显示,NH4^＋／NO3^- 1．0／60．0mmol／L、K^＋ 100．0mmol／L、Mg^2＋ 3．0mmol／L、H2PO4^- 3．0mmol／L、蔗糖30．0g／L、水解酪蛋白2．0g/L条件下,茶叶细胞生长量和茶氨酸积累量均达到最高值;提高培养基中蔗糖和水解酪蛋白浓度可使细胞对数生长期和稳定期得到延长,从而有利于茶氮酸积累;H2PO4^-浓度主要影响细胞生长速率和茶氨酸积累速率的同步性,低H2PO4^-浓度环境中茶氨酸积累速率峰值滞后于细胞增长速率峰值,高H2PO4^-浓度环境中早于细胞生长速率峰值出现时间;K^＋和Mg^2＋对细胞生长的影响不明显,但影响细胞茶氨酸合成酶活性,维持适量的K^＋和Mg^2＋有利于茶氨酸积累。添加盐酸乙胺可大幅度提高茶氨酸积累量,并且先加入一定量盐酸乙胺再每天进行少量补充,茶氨酸合成量比一次性加入的效果要好。茶叶细胞生长和茶氨酸积累高峰期在整个培养过程的第19～22天出现,从生产效率考虑,培养周期以19～22天为宜。     

氨基酸在茶叶中的分布、变化及其提高途径

<正> 氨基酸是茶叶中的重要含氮物质。很多氨基酸是组成蛋白质的基本单位,同时又是合成许多与代谢产物有关的生理活性物质先质。茶叶中的氨基酸种类很多,已发现的有25种以上,主要分布在叶、茎、根、果等部位。众多氨基酸中,以茶氨酸、谷氨酸、天门冬氨酸、精氨酸等含量较高,尤以茶氨酸含量最为突出,通常要占氨基酸总量的     

沉淀法从茶叶中提取茶氨酸

茶叶浸提液分别用1%壳聚糖和D101大孔吸附树脂去杂后,用碱式碳酸铜沉淀茶氨酸。茶氨酸铜盐用1mol/L硫酸解析,分别用H_2S、Ba(OH)_2除去Cu~(2 )、SO_4~(2 )后,浓缩重结晶得到茶氨酸,提取率34%,纯度99．28%。     

L-茶氨酸新型酶法制备及其催化工艺优化

L-茶氨酸是茶叶中游离氨基酸的主要组成部分,关于其良好的生理活性已有广泛报道。首次报道了来源于Cunnighamella echinulata 9980的L-氨基酰化酶用于高光学纯度的L-茶氨酸的酶法制备。该酶在pH 6.5,底物N-乙酰-DL-茶氨酸浓度为50 mM,且有40 mM CoCl2时催化效果较好。结果表明,在上述条件下,50℃作用12 h得L-茶氨酸22.5 mM,转化率90%。     

茶组植物中茶氨酸和没食子酸的高压液相色谱分析

应用高效液相色谱(HPLC)技术对茶属茶组的6种3变种植物叶中的茶氨酸和没食子酸含量进行定量分析.结果表明,茶氨酸和没食子酸均普遍存在于这几种茶组植物中,二者在大理茶与广西茶中的含量与大叶茶最为接近,野生的大理茶在云南民间亦作为茶叶的原料使用,有悠久的历史,提示大理茶有可能是大叶茶的基源植物之一.     

Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS

The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.     

Mass flow to the root system and mineral uptake of a beech stand calculated from 3-year field data

Summary Mass flow to the root surface is defined here as the concentration of an element in the bulk soil solution times the transpirational water uptake of the plant stand. The ratio of uptake of a mineral element to mass flow is called Mass Flow Coefficient (MFC). From an ecosystem study in a beech forestMFCs for 11 elements have been calculated from 3 years of monthly measurements. They amounted to 0.076, 0.086, 0.34, 0.77, 1.5, 1.7, 2.2, 2.9, 8.3, 11, and 120 for Al, Cl, Na, S, Fe, Mg, Mn, Ca, K, N and P respectively. It is concluded that this stand discriminates against Al, Cl and Na in ion uptake and takes up selectively Mn, Ca, K, N and P while for S, Fe and Mg mass flow transports almost the same amount to the root system as is taken up by the above ground stand.     

Phylogenetic relationships within the Gentianales based on NDHF and RBCL sequences, with particular reference to the Loganiaceae

Phylogenetic relationships in the Gentianales with focus on Loganiaceae sensu lato are evaluated using parsimony analyses of nucleotide sequence data from the plastid genes rbcL and ndhF. Inter- and intrafamilial relationships in the Gentianales, which consist of the families Apocynaceae (including Asclepiadaceae), Gelsemiaceae, Gentianaceae, Loganiaceae, and Rubiaceae, are studied and receive increased support from the combination of rbcL and ndhF data, which indicate that the family Rubiaceae forms the sister group to the successively nested Gentianaceae, Apocynaceae, and Loganiaceae, all of which are well supported. The family Gelsemiaceae forms a distinct, supported group sister to Apocynaceae. The Loganiaceae sensu stricto form a strongly supported group consisting of 13 genera: Antonia, Bonyunia, Gardneria, Geniostoma, Labordia, Logania, Mitrasacme, Mitreola, Neuburgia, Norrisia, Spigelia, Strychnos, and Usteria. These genera form two well-supported lineages. Several members of Loganiaceae sensu Leeuwenberg and Leenhouts, i.e., Androya, Peltanthera, Plocosperma, Polypremum, and Sanango are clearly not members of the Gentianales. The earlier exclusion of Buddlejaceae (including Buddleja, Emorya, Gomphostigma, and Nicodemia) as well as the reclassification of the genera Nuxia and Retzia to Stilbaceae of the Lamiales are all well supported.     

Trypanosoma congolense. II. Histopathologic findings in experimentally infected cattle

Heart, kidney, lung, liver, brain, spleen, lymph nodes, tongue, and diaphragm of 9 cattle experimentally infected with the Trans Mara I strain of Trypanosoma congolense, were examined histologically. A haemosiderosis, infiltrations in the kidney, changes in the vascular wall mainly of the arteries of the lung, scattered local perivascular, and meningeal infiltrations, and small juxtavascular glial nodules in the CNS were found.     

Infection status with helminthes in feral cats purchased from a market in Busan, Republic of Korea

The present study was performed to investigate the infection status with helminth in a group of feral cats in Korea. More than 29 helminth species including adults or eggs were detected in visceral and fecal samples of the examined cats. Among these were a host of nematodes, including toxocarids, Ancylostoma sp. and the larva of Anisakis simplex; trematodes, including Clonorchis sinensis, Paragonimus westermani, Eurytrema pancreaticum, Pharyngostomum cordatum, Metagonimus spp., Heterophyes nocens, Pygidiopsis summa, Heterophyopsis continua, Stictodora fuscata, Stictodora lari, Acanthotrema felis, Stellantchasmus falcatus, Centrocestus armatus, Procerovum varium, Cryptocotyle sp., Echinostoma revolutum, Echinostoma hortense, Echinochasmus japonicus, Stephanoprora sp., Plagiorchis muris, Neodiplostomum sp. and diplostomulum. We also detected a variety of cestodes, including Spirometra erinacei, Taenia taeniaeformis and unidentified species of tapeworm. We also found examples of the acanthocephalan, Bolbosoma sp. In our assessment of the stools, we detected at least 12 species of helminth eggs. These findings confirmed that feral cats in Korea are infected with a variety of helminth parasite species. Furthermore, among the helminths detected, E. pancreaticum, S. fuscata, S. lari, A. felis, S. falcatus, C. armatus, P. varium, Cryptocotyle sp., E. revolutum, E. japonicus, Stephanoprora sp., P. muris, Neodiplostomum sp. and Bolbosoma sp. represent helminth fauna which have not been reported previously in feral cats in the Republic of Korea.     

Prospective Biological Control Agents of Varroa destructor n. sp., an Important Pest of the European Honeybee, Apis mellifera

This paper reviews prospective biological control agents of the varroa mite, Varroa destructor n. sp. (Acari, Mesostigmata). This ectoparasite has caused severe damage to populations of the European honeybee, Apis mellifera , world-wide in recent years. To date, no promising natural enemies of varroa species have been identified on A. mellifera or its original host, Apis cerana . Therefore, biological control will probably require natural enemies from other hosts. The following groups of organisms were reviewed as potential biological control agents: predatory mites, parasitoids and entomopathogens (nematodes, protozoa, viruses, Bacillus thuringiensis , rickettsiae, and fungi). The candidate groups were ranked according to their lethality to Acari, likely ability to operate under the physical conditions of honeybee colonies, ease of targeting, and ease of mass-production. Preferential consideration was given to the natural enemies of Acari that occupy taxonomic groups close to varroa. Entomopathogenic fungi, which kill a wide range of acarine species, were identified as prime candidates for screening against varroa. Bacillus thuringiensi s also requires study, particularly strains producing novel toxins active against non-insect hosts. Entomopathogenic protozoa and nematodes show less potential for varroa control, but nonetheless warrant preliminary investigation. We consider predators, parasitoids, viruses and rickettsiae to have little potential to control varroa. Because the physical conditions within honeybee colonies are similar everywhere, it is very likely that a biological control agent of varroa could be used successfully throughout the world.     

Quantification of 26 metals in human urine samples using ICP-MSMS in a random sample collective of an occupational and environmental health care center in Aachen,Germany

Despite several studies on metal exposure in the general population, the knowledge on the background burden of distinct metals is still sparse (e.g. Cu, In, Mn, Pb, Sn, Sr, Ta, Te). While up to date reference values exist for 16 distinct metals as Biological Reference Value (BAR) or the 95th percentile for Al, As, Ba, Be, Cd, Co, Cr, Hg, Li, Mo, Ni, Pt, Sb, Se, Tl and U respectively, the background burden of the general population for the remaining elements is unknown or yet no matter of scientific counselling. We established and validated an inductively coupled plasma triple quadrupole mass spectrometry (ICP-MSMS) human biomonitoring method (HBM), that enabled us to determine 26 metals in urine. Al, As, Ba, Be, Cd, Co, Cu, Ga, Gd, Hg, In, Li, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ta, Te, Tl, V and Zn were analyzed. The method was applied to 88 urine samples collected in the ambulance of the Institute for Occupational, Social and Environmental Medicine (IASU) Aachen, Germany. Patients from two major metal processing companies (steel and copper) and a more heterogenous group of occupational exposed and non-exposed persons were defined and distinguished. HBM data from about 88, in general occupationally unexposed persons against certain metals served as a collective representing the general population in first approximation. For these the 95th percentiles are reported. Significant differences of urinary metal concentrations of the employees of the two metal processing companies compared to the third group were observed among others for Cu, Cr, Ni, Mn and are discussed, thus demonstrating the usefulness of the method for both environmental and occupational purposes.