15 February 2011, Volume 31 Issue 1

    

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  Review on Enzymatic Biosynthesis of Theanine

  CHEN Lin, ZHANG Zheng-zhu, CHEN Jian, ZHANG Ying-gen, WAN Xiao-chun

  Journal of Tea Science. 2011, 31(1): 1-10. https://doi.org/10.13305/j.cnki.jts.2011.01.001

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  As a characteristic component in tea plant (Camellia sinensis), theanine has many favorable physiological effects, such as promoting relaxation, enhancing memory, neuroprotection, modulation of chemotherapy, etc. So far, seven kinds of enzyme have been discovered by which theanine can be synthesized. They are respectively named as theanine synthetase, glutamine synthetase, γ-glutamylmethylamide synthetase, glutamate synthetase, γ-glutamylcysteine synthetase, glutaminase and γ-glutamyltranspeptidase. The two representative reaction types for theanine biosynthesis are linking reaction between glutamic acid and ethylamine in the presence of ATP and γ-glutamyl transfer reaction in which γ-glutamyl group from hydrolysis of glutamine is transferred to ethylamine. In order to apply and develop the exiting methods for microbial production of theanine, the ways involved in enzymatic synthesis of theanine are systematically summarized in this paper.
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  Relations between Tea Yields & Quality and Applied Ratio of NPK Fertilizers in the Initial Production Tea Garden

  TANG Jin-chi, WU Li-rong, WU Jia-yao, TANG Hao, LI Jian-long, PANG Shi

  Journal of Tea Science. 2011, 31(1): 11-16. https://doi.org/10.13305/j.cnki.jts.2011.01.002

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  Through the cement pond cultivation method to conduct the NPK fertilizer ratio test in the initial production tea garden, the results indicated that different proportions of NPK fertilizers showed a great influence on the growth characters and yield of tea plant. The difference between the treatments was significant or very significant; single application or matching application with different levels of NPK fertilizer affected biochemical composition of the shoots significantly. The amino acids significantly increased, with increasing of the amount of applied nitrogen. Application of P and K improved the quality of black tea,but separate application of N fertilizer reduced the quality of black tea. The final conclusion showed a good effect for tea production in the initial production tea garden with application fertilizer pure nitrogen per year 150kg/hm², phosphorus (P₂O₅) 150kg/hm², potassium (K₂O) 75kg/hm², under this fertilizing level, not only the production and quality were increased and improved, the growth potential of young tea plant was also enhanced, thus laying the foundation for mature garden to gain high yields.
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  Effect of Theanine’s Immuno-enhancement and Acute Toxicity Based on ICR Mice

  TAN Jun-feng, LI Liang, HE Pu-ming, LV Hai-peng, GUO Li, LIN Zhi

  Journal of Tea Science. 2011, 31(1): 17-21. https://doi.org/10.13305/j.cnki.jts.2011.01.003

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  The effect of theanine on immuno-enhancement ability was evaluated. Results showed that theanine nearly has no impact on mice immune organs. And theanine could effectively enhance the clearing ability of mice. Theanine could also effectively increase the DTH of mice in DNFB induced tests (all does groups being higher compare with the model does), and especially, the high does increased most. The maximal tolerance dose (MTD) on theanine is more than 20.0g/kg, which illustrate theanine is non-toxic.
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  Clinical Observation of Tea Polyphenol Tablet on Chronic Glomerulonephritis

  WANG Yue-fei, SHI Xiao-yun, XU Ping, WANG Guan-qiao, WU Zheng-qi, YANG Xian-qiang

  Journal of Tea Science. 2011, 31(1): 22-26. https://doi.org/10.13305/j.cnki.jts.2011.01.004

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  To evaluate the efficiency and safety of tea polyphenol tablet on chronic glomerulonephritis in clinic, a multi-centre, prospective, double-blind and double-mimicry, positive control (shenyan siwei tablet) trial was conducted, and 240 patients (120 patients of treated group and 120 patients of control group) was observed for 8 weeks. After 8 weeks’ treatment, the efficacy in cured rate of relieving clinical symptoms of patiens, the scores of symptoms efficacy, urinary protein efficacy and urine erythrocyte efficacy were 35.0%, 38.5%, 49.6% and 59.7% respectively in tea polyphenol tablet group, and the total effective rate were 71.8%, 86.1%, 80.0% and 72.6% respectively. It showed no difference comparing with positive control group. No adverse effects appeared during the trial, both tea polyphenol tablet and shenyan siwei tablet were evaluated as first-level safety by the patients of trial group and positive control group. All results suggested that tea polyphenol tablet is an efficient and safe drug in treatment of chronic glomerulonephritis, and its efficacy is not less than shenyan siwei tablet.
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  Study on Variation of Chlorophyllase Activity in Tea Plant (Camellia sinensis)

  LI Yuan-hua, GU Wei, NI De-jiang, YANG Jiang-fan, ZHENG Fang, SHI Yu-tao

  Journal of Tea Science. 2011, 31(1): 27-32. https://doi.org/10.13305/j.cnki.jts.2011.01.005

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  The variation of chlorophyllase activity in tea plant（Camellia Sinensis）was investigated. The results showed that the diurnal variation of chlorophyllase activity decreased gradually from 7:00 to 16:00, and then showed an upward tendency from 16:00 to 19:00. The chlorophyllase activity diversity also existed in various seasons and leaf tenderness. The activity of chlorophyllase in the shoots of tea plant was highest in spring and lowest in autumn, and it took second place in summer. In the different growth position of tea plant, the chlorophyllase activity decreased with an order of bud > the first leaf > the second leaf > the third leaf > the old leaf > the young stem. During the fresh leaf spreading process of 6-hour treatment, the activity of chlorophyllase declined at the beginning and increased greatly later. The activity of chlorophyllase in eight different cultivars of Camellia Sinensis was determined. The results indicated that the sequence of the chlorophyllase activity among different cultivars from high to low was Fuyunliuhao>Fudingdahao>Fudingdahao>Echa1>Pingyangtezao>Wuniuzao>Yingshuang>Longjing 43. Further than that, the influence of overhead shading in tea garden on the chlorophyllase activity was studied. The result suggested that the activity of chlorophyllase both decreased after the treatment of 60% shading rate and 80% shading rate.
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  Bioinformatic Analysis and Prokaryotic Expression of Polyphenol Oxidase Gene in Tea Plant (Camellia sinensis)

  WANG Nai-dong, ZHANG Li-xia, XIANG Qin-zeng, LI Wei-wei

  Journal of Tea Science. 2011, 31(1): 33-39. https://doi.org/10.13305/j.cnki.jts.2011.01.006

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  The polyphenol oxidase (PPO, GenBank accession No. DQ812086) gene was amplified by PCR. Bioinformatics analysis indicated that the cds of PPO DNA sequence is 1800bp, which encoded a protein of 599 amino acid residues (molecular formula: C₃₀₀₈H₄₆₇₇N₈₁₃O₉₀₀S₁₈) and predicted that it had two Cu-band functional domains with no transmembrane. The phylogeny analysis showed that it has a most close phylogenetic relationship with Camellia nitidissima. The PPO was cloned into pET28a vector to construct recombination prokaryotic expression vector pET-ppo. After transformed to E1coli BL21 and induced by isopropyl-β-D-thiogalactopyranoside(IPTG), recombinant protein about 71kD was expressed in pET28a system and separated by SDS-PAGE electrophoresis.
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  Genetic Diversity and Differentiation of Longjing Tea Population Based on SSR Markers

  WANG Li-yuan, JIANG Yan-hua, DUAN Yun-shang, CHENG Hao, ZHOU Jian, ZENG Jian-ming, WEI Kang

  Journal of Tea Science. 2011, 31(1): 40-44. https://doi.org/10.13305/j.cnki.jts.2011.01.007

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  The genetic diversity and differentiation of 91 individuals from five populations of Longjing tea landrace were characterized by 48 pairs of SSR markers. It was showed that the level of genetic diversity within Longjing tea population was high. The polymorphism information content (PIC) was ranging from 0.0567 to 0.7476 and the average PIC was 0.4382. Among 48 SSR sites in study, 16 was high polymorphism, 30 was medium polymorphism. Hardy-Weinberg equiliberum (HWE) test showed that 33.3% SSR sites were in accord with the HWE and 66.7% sites were not in HWE. AMOVA analysis showed that percentage variation among populations was 3.45% and percentage variation within individuals was 94.98%. The genetic differentiation was lower in Longjing tea population, the fixation indices within individuals and among populations was 0.0502 (FIT) and 0.0345 (FST) respectively.
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  Identification, Evaluation and Screening on Elite and Rare Tea Germplasms from Yunnan Province

  SONG Wei-xi, LIU Ben-ying, YI Bing, JIANG Hui-bing, MA Ling, DUAN Zhi-fen, SUN Xue-mei, WANG Yun-gang, WANG Ping-sheng

  Journal of Tea Science. 2011, 31(1): 45-52. https://doi.org/10.13305/j.cnki.jts.2011.01.008

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  The agronomic traits, made tea quality, chemical components, cold tolerance and resistance to pests and diseases of 500 accessions tea germplasms collected from Yunnan Province were systematically and comprehensively investigated during 1986~2005. A total of 52 well-performed accessions tea germplasms were screened out according to nearly 100 characteristics. Among which, 32 accessions were relatively coordinated polyphenols, amino acids, caffeine and water extract contents, 2 super early maturity, 5 high polyphenols contents(>38%), 7 high caffeine content(>5.2%), 2 high caffeine content(<1%), 10 high theaflavins content(>1.6%), 26 high water extracts content(>48%), 2 high resistant to root knot nematode, 1 high resistant to tea leafhopper, 2 high resistant to tea red spider mite and 6 strong cold tolerance germplasms.
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  Cloning and Expression Analysis of Stress-resistant ERF Genes from Tea Plant [Camellia sinensis (L.) O. Kuntze]

  CHEN Lin-bo, FANG Chao, WANG Yu, LI Ye-yun, JIANG Chang-jun, LIANG Ming-zhi

  Journal of Tea Science. 2011, 31(1): 53-58. https://doi.org/10.13305/j.cnki.jts.2011.01.009

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  For A TDF, which has been gained from genes expressed differentially in tea plant under cold stress using cDNA-AFLP, containing a complete coding sequence cDNA was cloned by RACE,named CsERF, and contains an ORF, which encodes a polypeptide of 212 amino acids including a conserved AP2 domains. Sequence alignment showed that CsERF protein shared high identity with other plants. qRT-PCR analysis showed that ERF gene was up-regulated by cold, ethylene, dehydration, NaCl and the maximum expression were 121.1, 22.6, 2.6, 2.2 times higher than before treatment, respectively. For different tea organs, transcriptional level of the ERF gene was the highest in mature leaves, the next was in bud, the third was in root and stem, and the lowest in flower and seed. It deduced that ERF gene was very important for tea plant in response to abiotic stress and was strictly controlled in expression of different organs.
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  Young Shoot Purple-Related Gene Screening in Tea Plant (Camellia sinensis) by Using cDNA Microarray

  MA Chun-lei, YAO Ming-zhe, WANG Xin-chao, JIN Ji-qiang, CHEN Liang

  Journal of Tea Science. 2011, 31(1): 59-65. https://doi.org/10.13305/j.cnki.jts.2011.01.010

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  Young shoots purple-related differentially expressed genes of tea plant have been found in purple and green shoots line of Longjing Qunti by cDNA microarray technique. There were 43 differentially expressed genes relating to purple shoots, among them 17 were up-regulated and 26 were down-regulated genes. Three differentially expressed genes and two no change genes were selected to verify the results of cDNA microarray hybridizations. The result of real time RT-PCR analysis was consistent with that of cDNA microarray. Then all of the differentially expressed genes were annotated functionally by Blast X search against the NCBI non-redundant protein databases. The molecular function of differentially expressed genes mainly included energy metabolism, secondary metabolism and transcriptional regulation. Especially two genes and two transcription factors involved in the biosynthesis pathway of anthocyanidin were selected from the results of cDNA microarray hybridizations. The phenylalanine ammonia lyase gene, MYB protein, WD40-like protein, and anthocyanidin reductase gene showed down-regulated 3.44, 2.25, 2.54 folds and up-regulated 2.09 folds, respectively. This study establishes a basis for further understanding the purple mechanism of tea young shoots and related gene cloning.
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  Estimating the Quality of Tea Leaf Materials Based on Contents of Moisture, Total Nitrogen and Crude Fiber by NIR-PLS Techniques

  WANG Sheng-peng, WAN Xiao-chun, LIN Mao-xian, ZHANG Zheng-zhu

  Journal of Tea Science. 2011, 31(1): 66-71. https://doi.org/10.13305/j.cnki.jts.2011.01.011

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  In order to estimate the quality of the fresh tea leaves by near infrared spectrum (NIRS) technique, the correlative model equation between near infrared spectrum of the fresh tea leaves and their corresponding moisture, crude fiber and total nitrogen amounts respectively through cross-validation and partial least squares (PLS) method were established in this paper. When the dimension was 7, the three indicators of R value were 0.92, 0.86 and 0.90, root mean square error of cross-validation (RMSECV) were 0.769, 0.332 and 0.742, respectively. A quality coefficient equation was suggested depending on the contents of moisture, crude fiber and entire nitrogen of fresh tea leaves. According to the quality coefficient equation of fresh tea leaf raw material, the quality coefficient of fresh tea leaves was obtained. The larger quality coefficient is, the higher quality of fresh leaf is. Thus, we developed a new method for the evaluation for the quality of fresh tea leaves by using NIRS was developed.
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  Segmentation Algorithm of Tea Combined withthe Color and Region Growing

  WANG Jian

  Journal of Tea Science. 2011, 31(1): 72-77. https://doi.org/10.13305/j.cnki.jts.2011.01.012

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  Growth conditions and degree of maturity are two important factors affecting the quality of tea, while accurate segmentation of tea images is the precondition to analyze and identify the tea leaves. In this paper, an improved method based on the color and regional growth of tea is introduced to conduct the image segmentation of tender tea shoots. Firstly, the RGB color images are converted into HSI space, and then H and S parameters are selected for the initial selection of tea seed. Secondly, the regional growth based on color similarity and regional adjacency are conducted on the seed region, and then the color and edge distance is used to carry out regional growing and mergence. The image segmentation of tender tea shoots acquired from the different perspectives are conduced and compared, and the results indicate that this algorithm performs well in separating tender shoots from leaves and maintaining the outline of tender shoots.