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Quantitative Analysis of ATP Sulfurylase and Selenocysteine Methyltransferase Gene Expression in Different Organs of Tea Plant (Camellia sinensis)  [PDF]
Shaoqiang Tao, Juan Li, Xungang Gu, Yanan Wang, Qiang Xia, Bing Qin, Lin Zhu
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.31004
Abstract: Tea plant (Camellia sinensis) has unique biological features for the study of cellular and molecular mechanisms, an evergreen broad-leaved woody plant which can accumulate selenium in soil abundant of Selenium. Expression of the genes related to Selenium (Se) metabolism is an adaptation to the soil environment for a long period. The purpose of the present study was to explore if there exist differences of expression about these genes in tea plant between growing in Selenium-abundant and normal soil. A quantitative real-time reverse transcription polymerase chain reaction (Q-RT-PCR) assay was done for quantification of ATP sulfurylase (APS) and selenocysteine methyltransferase (SMT) mRNA normalized to Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene in tea plant. Young leaves, mature leaves and tender roots from tea plants growing in soil abundant of Selenium were respectively obtained from Shitai County, Anhui Province, and also the relevant materials of the selenium un-enriched tea plant planted at agricultural garden of Ahui Agriculture University were taken as control for real-time PCR analysis. The results showed that APS1, APS2 and SMT expression levels for either young or mature leaves in selenium-enriched tea plant were lower than that in ordinary (selenium un-enriched) tea plant. In contrast, the APS1, APS2 and SMT expression level of roots in selenium-enriched tea plant were all higher than that in ordinary tea plant. APS1 gene expression level of roots in selenium-enriched tea plant was about 1.6 times higher than that in the ordinary tea plant, APS2 gene expression level was about 4.8-fold higher than that in the ordinary tea plant, SMT gene expression level was about 3.3 times higher than that in the ordinary tea plant. Among various tissues of selenium-enriched tea plant, APS1 gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the lowest among them; APS2 gene relative expression level of young leaves was similar to or slightly higher than the roots, and the one of mature leaves was the lowest among them; SMT gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the highest among them. Our results suggest that there existed correlation between selenium and expression levels of these genes.
Production of Se-methylselenocysteine in transgenic plants expressing selenocysteine methyltransferase
Danielle Ellis, Thomas G Sors, Dennis G Brunk, Carrie Albrecht, Cindy Orser, Brett Lahner, Karl V Wood, Hugh Harris, Ingrid J Pickering, David E Salt
BMC Plant Biology , 2004, DOI: 10.1186/1471-2229-4-1
Abstract: By over producing the A. bisulcatus enzyme selenocysteine methyltransferase in A. thaliana, we have introduced a novel biosynthetic ability that allows the non-accumulator to accumulate Se-methylselenocysteine and γ-glutamylmethylselenocysteine in shoots. The biosynthesis of Se-methylselenocysteine in A. thaliana also confers significantly increased selenite tolerance and foliar Se accumulation.These results demonstrate the feasibility of developing transgenic plant-based production of Se-methylselenocysteine, as well as bioengineering selenite resistance in plants. Selenite resistance is the first step in engineering plants that are resistant to selenate, the predominant form of Se in the environment.Selenium is an essential nutrient for animals, microorganisms and some other eukaryotes [1]. While Se deficiency is rare in the US, it does occur in several low Se parts of the world such as China, and can lead to heart disease, hypothyroidism and a weakened immune system [2,3]. The toxic effects of excess Se have been known for some time. Short-term consumption of high levels of Se may cause nausea, vomiting, and diarrhea, whereas chronic consumption of high concentrations of Se compounds can result in a disease called selenosis [4]. Only one form of Se, selenium sulfide, has been implicated as a carcinogen [4]. The recognition of Se bioaccumulation and resulting wildlife toxicity at Kesterson reservoir in California and other sites has resulted in a surge of interest in phytoremediation of Se [5-8]. Selenium in the environment can be the result of either natural geological processes or human activities. The USGS has identified 160,000 miles2 of land in the western US enriched in Se from natural processes that is susceptible to irrigation-induced Se contamination, including 4,100 miles2 of land currently irrigated for agriculture [9]. Selenium pollution can also arise from various industrial and manufacturing processes including procurement, processing, and combustion
Anthelmintic activity of Tea (Camellia sinensis) extract  [PDF]
Gaurav Dwivedi,Deependra Rawal,Sunil Nagda,,Tarun Jain
International Journal of Pharma Sciences and Research , 2010,
Abstract: The aim of present study was the evaluation of anthelmintic activity of Tea Powder (Camellia sinensis) extract in experimental adult earthworm’s pheritima posthuma. The alcoholic & aqueous extract of Tea Powder (Camellisa sinensis) show potent anthelmintic activity.
Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea  [PDF]
Michael Rother,Joseph A. Krzycki
Archaea , 2010, DOI: 10.1155/2010/453642
Abstract: Methanogenic archaea are a group of strictly anaerobic microorganisms characterized by their strict dependence on the process of methanogenesis for energy conservation. Among the archaea, they are also the only known group synthesizing proteins containing selenocysteine or pyrrolysine. All but one of the known archaeal pyrrolysine-containing and all but two of the confirmed archaeal selenocysteine-containing protein are involved in methanogenesis. Synthesis of these proteins proceeds through suppression of translational stop codons but otherwise the two systems are fundamentally different. This paper highlights these differences and summarizes the recent developments in selenocysteine- and pyrrolysine-related research on archaea and aims to put this knowledge into the context of their unique energy metabolism. 1. Introduction Expansion of the amino acid repertoire of proteins beyond the 20 “canonical” amino acids is a phenomenon observed almost 50 years ago [1]. Numerous modifications of the carboxyl- or amino-terminals or the individual side chains of amino acids after ribosomal synthesis of the respective polypeptide had finished were identified and the biosynthetic path elucidated (reviewed in [2]). It is thus not surprising that a similar process was assumed when selenocysteine, 2-selenoalanine, was discovered as constituent of eukaryal and bacterial proteins [3]. What made selenocysteine special is that subsequent efforts established the cotranslational nature of its insertion into proteins at the position of a UGA stop codon on the respective mRNA [4, 5]. Thus, selenocysteine was designated the 21st proteinogenic amino acid [6]. Discovery of pyrrolysine, lysine with in amide linkage to (4R,5R)-4-methyl-pyrroline-5-carboxylate, occurred in a different order, a single in-frame amber codon within the gene encoding the monomethylamine (MMA) methyltransferase in Methanosarcina barkeri [7, 8] was later found to correspond to pyrrolysine in the crystal structure [9, 10] and have its own tRNA [11]. As pyrrolysine was also shown to be inserted cotranslationally, it was designated the 22nd proteinogenic amino acid [10]. Beside the fact that translation of selenocysteine and pyrrolysine both involves suppression of stop codons the two systems have little in common (also reviewed in [12, 13]). To emphasize the differences between the mechanisms underlying selenocysteine and pyrrolysine translation, to summarize recent insights from efforts to better understand the biology of these two unusual amino acids, and to put this knowledge into the physiological
Kinetic mechanism of the dimeric ATP sulfurylase from plants  [cached]
Geoffrey?E. Ravilious,Jonathan Herrmann,Soon Goo Lee,Corey?S. Westfall
Bioscience Reports , 2013, DOI: 10.1042/bsr20130073
Abstract: In plants, sulfur must be obtained from the environment and assimilated into usable forms for metabolism. ATP sulfurylase catalyses the thermodynamically unfavourable formation of a mixed phosphosulfate anhydride in APS (adenosine 5′-phosphosulfate) from ATP and sulfate as the first committed step of sulfur assimilation in plants. In contrast to the multi-functional, allosterically regulated ATP sulfurylases from bacteria, fungi and mammals, the plant enzyme functions as a mono-functional, non-allosteric homodimer. Owing to these differences, here we examine the kinetic mechanism of soybean ATP sulfurylase [GmATPS1 (Glycine max (soybean) ATP sulfurylase isoform 1)]. For the forward reaction (APS synthesis), initial velocity methods indicate a single-displacement mechanism. Dead-end inhibition studies with chlorate showed competitive inhibition versus sulfate and non-competitive inhibition versus APS. Initial velocity studies of the reverse reaction (ATP synthesis) demonstrate a sequential mechanism with global fitting analysis suggesting an ordered binding of substrates. ITC (isothermal titration calorimetry) showed tight binding of APS to GmATPS1. In contrast, binding of PPi (pyrophosphate) to GmATPS1 was not detected, although titration of the E APS complex with PPi in the absence of magnesium displayed ternary complex formation. These results suggest a kinetic mechanism in which ATP and APS are the first substrates bound in the forward and reverse reactions, respectively.
Structural, Biochemical and Genetic Characterization of Dissimilatory ATP Sulfurylase from Allochromatium vinosum  [PDF]
Kristian Parey, Ulrike Demmer, Eberhard Warkentin, Astrid Wynen, Ulrich Ermler, Christiane Dahl
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074707
Abstract: ATP sulfurylase (ATPS) catalyzes a key reaction in the global sulfur cycle by reversibly converting inorganic sulfate (SO42?) with ATP to adenosine 5′-phosphosulfate (APS) and pyrophosphate (PPi). In this work we report on the sat encoded dissimilatory ATP sulfurylase from the sulfur-oxidizing purple sulfur bacterium Allochromatium vinosum. In this organism, the sat gene is located in one operon and co-transcribed with the aprMBA genes for membrane-bound APS reductase. Like APS reductase, Sat is dispensible for growth on reduced sulfur compounds due to the presence of an alternate, so far unidentified sulfite-oxidizing pathway in A. vinosum. Sulfate assimilation also proceeds independently of Sat by a separate pathway involving a cysDN-encoded assimilatory ATP sulfurylase. We produced the purple bacterial sat-encoded ATP sulfurylase as a recombinant protein in E. coli, determined crucial kinetic parameters and obtained a crystal structure in an open state with a ligand-free active site. By comparison with several known structures of the ATPS-APS complex in the closed state a scenario about substrate-induced conformational changes was worked out. Despite different kinetic properties ATPS involved in sulfur-oxidizing and sulfate-reducing processes are not distinguishable on a structural level presumably due to the interference between functional and evolutionary processes.
Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea  [PDF]
Michael Rother,Joseph A. Krzycki
Archaea , 2010, DOI: 10.1155/2010/453642
Abstract: Methanogenic archaea are a group of strictly anaerobic microorganisms characterized by their strict dependence on the process of methanogenesis for energy conservation. Among the archaea, they are also the only known group synthesizing proteins containing selenocysteine or pyrrolysine. All but one of the known archaeal pyrrolysine-containing and all but two of the confirmed archaeal selenocysteine-containing protein are involved in methanogenesis. Synthesis of these proteins proceeds through suppression of translational stop codons but otherwise the two systems are fundamentally different. This paper highlights these differences and summarizes the recent developments in selenocysteine- and pyrrolysine-related research on archaea and aims to put this knowledge into the context of their unique energy metabolism.
A NEW SPECIES OF BIFUSELLA ON CAMELLIA SINENSIS
茶树上斑痣盘菌科一新种

HOU Cheng-lin,
侯成林

菌物学报 , 2000,
Abstract: A new species of the genus Bifusella v. Hoehn., B. camelliae on Camellia sinensis is described.Discussion on distinguishing the new species from similar species is given. The type specimen is deposited inthe Forest Protection Laboratory of Anhui Agricultural University, Hefei.
Volatile Components of Camellia sinensis Inhibit Growth and Biofilm Formation of Oral Strepto  [PDF]
Alireza Shoae Hassani,Nour Amirmozafari,Negar Ordouzadeh,Kasra Hamdi
Pakistan Journal of Biological Sciences , 2008,
Abstract: This study aimed to evaluate the efficacy of semi fermented and non fermented Camellia sinensis extracts (Black and Green tea) and comparison between them against Streptococcus mutans ATCC 25175, S. mitis ATCC 9811 and S. sanguis ATCC 10556 that are responsible for dental caries and bacteremias following dental manipulations. Minimum inhibitory concentrations of both tea extracts were assessed by Well diffusion and Broth dilution methods and examination of cell adherence (Biofilm inhibitory concentrations) was observed on glass slides under phase contrast microscope and colony counts from glass beads. Concentration of 1 mg mL-1 of semi fermented tea extract was completely biofilm inhibitor but biofilm formation by these bacteria was seen 7 days after treatment with 1 mg mL-1 of non fermented Camellia sinensis on glass beads and BIC for oral streptococci treated with this extract was 1.5, 2.5 mg mL-1 of semi fermented and 3 mg mL-1 of non fermented extracts had bactericidal effect on these bacteria. Semi fermented and non fermented Camellia sinensis extracts were able to prevent growth of oral streptococci. Therefore dental caries significantly reduce and the efficiency of semi fermented tea was higher due to rich content of volatile components rather than non fermented extracts.
Biosynthesis of Selenocysteine on Its tRNA in Eukaryotes  [PDF]
Xue-Ming Xu,Bradley A. Carlson,Heiko Mix,Yan Zhang,Kazima Saira,Richard S. Glass,Marla J. Berry,Vadim N. Gladyshev,Dolph L. Hatfield
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0050004
Abstract: Selenocysteine (Sec) is cotranslationally inserted into protein in response to UGA codons and is the 21st amino acid in the genetic code. However, the means by which Sec is synthesized in eukaryotes is not known. Herein, comparative genomics and experimental analyses revealed that the mammalian Sec synthase (SecS) is the previously identified pyridoxal phosphate-containing protein known as the soluble liver antigen. SecS required selenophosphate and O-phosphoseryl-tRNA[Ser]Sec as substrates to generate selenocysteyl-tRNA[Ser]Sec. Moreover, it was found that Sec was synthesized on the tRNA scaffold from selenide, ATP, and serine using tRNA[Ser]Sec, seryl-tRNA synthetase, O-phosphoseryl-tRNA[Ser]Sec kinase, selenophosphate synthetase, and SecS. By identifying the pathway of Sec biosynthesis in mammals, this study not only functionally characterized SecS but also assigned the function of the O-phosphoseryl-tRNA[Ser]Sec kinase. In addition, we found that selenophosphate synthetase 2 could synthesize monoselenophosphate in vitro but selenophosphate synthetase 1 could not. Conservation of the overall pathway of Sec biosynthesis suggests that this pathway is also active in other eukaryotes and archaea that synthesize selenoproteins.
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