Transfer action of cyclodextrin glycosyltransferase on starch

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Kitahata, S; Okada, S [Osaka City Technical Research Inst. (Japan)

1975-11-01

The transglycosylation reaction of the cyclodextrin glycosyltransferase from Bacillus megaterium (No. 5 enzyme) and Bacillus macerans (BMA) were examined. No.5 enzyme was more efficient in transglycosylation reaction than BMA in the every acceptor employed in the present study. The order of the efficient acceptors for No. 5 enzyme was maltose (G2), glucose (G1), maltotriose (G3) and sucrose (GF). On the other hand, that found for BMA was G1, G2, GF and G3. The transglycosylation products to glucose formed by the action of No. 5 enzyme on starch were G2, G3, maltotetraose (G4), maltopentaose (G5), maltohexaose (G6) and maltoheptaose (G7) in the order of their quantities, while, in the case of BMA, they were G2, G3, G5, G7 = G4 and G6. The larger transglycosylation products to sucrose formed by the action of No. 5 enzyme on starch were maltosylfructose. On the other hand, that formed by the action of BMA was maltoheptaosylfructose. It was suggested that cyclodextrin glycosyltransferase could transfer the glucosyl residues to an acceptor directly from starch, as well as through cyclodextrin.

Screening of recombinant glycosyltransferases reveals the broad acceptor specificity of stevia UGT-76G1.

Science.gov (United States)

Dewitte, Griet; Walmagh, Maarten; Diricks, Margo; Lepak, Alexander; Gutmann, Alexander; Nidetzky, Bernd; Desmet, Tom

2016-09-10

UDP-glycosyltransferases (UGTs) are a promising class of biocatalysts that offer a sustainable alternative for chemical glycosylation of natural products. In this study, we aimed to characterize plant-derived UGTs from the GT-1 family with an emphasis on their acceptor promiscuity and their potential application in glycosylation processes. Recombinant expression in E. coli provided sufficient amounts of enzyme for the in-depth characterization of the salicylic acid UGT from Capsella rubella (UGT-SACr) and the stevia UGT from Stevia rebaudiana (UGT-76G1Sr). The latter was found to have a remarkably broad specificity with activities on a wide diversity of structures, from aliphatic and branched alcohols, over small phenolics to larger flavonoids, terpenoids and even higher glycoside compounds. As an example for its industrial potential, the glycosylation of curcumin was thoroughly evaluated. Under optimized conditions, 96% of curcumin was converted within 24h into the corresponding curcumin β-glycosides. In addition, the reaction was performed in a coupled system with sucrose synthase from Glycine max, to enable the cost-efficient (re)generation of UDP-Glc from sucrose as abundant and renewable resource. Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary X-ray crystallographic analysis of the glycosyltransferase from a marine Streptomyces species

International Nuclear Information System (INIS)

Gong, Liping; Xiao, Yi; Liu, Qiang; Li, Sumei; Zhang, Changsheng; Liu, Jinsong

2010-01-01

The recombinant glycosyltransferase ElaGT from the elaiophylin-producing marine Streptomyces sp. SCSIO 01934 has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 2.9 Å resolution. ElaGT is a glycosyltransferase from a marine Streptomyces species that is involved in the biosynthesis of elaiophylin. Here, the molecular cloning, protein expression and purification, preliminary crystallization and crystallographic characterization of ElaGT are reported. The rod-shaped crystals belonged to space group P2 1 22, with unit-cell parameters a = 66.7, b = 131.7, c = 224.6 Å, α = 90, β = 90, γ = 90°. Data were collected to 2.9 Å resolution. A preliminary molecular-replacement solution implied the presence of two ElaGT molecules in the asymmetric unit

Glycosyltransferase Gene Expression Profiles Classify Cancer Types and Propose Prognostic Subtypes

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Ashkani, Jahanshah; Naidoo, Kevin J.

2016-05-01

Aberrant glycosylation in tumours stem from altered glycosyltransferase (GT) gene expression but can the expression profiles of these signature genes be used to classify cancer types and lead to cancer subtype discovery? The differential structural changes to cellular glycan structures are predominantly regulated by the expression patterns of GT genes and are a hallmark of neoplastic cell metamorphoses. We found that the expression of 210 GT genes taken from 1893 cancer patient samples in The Cancer Genome Atlas (TCGA) microarray data are able to classify six cancers; breast, ovarian, glioblastoma, kidney, colon and lung. The GT gene expression profiles are used to develop cancer classifiers and propose subtypes. The subclassification of breast cancer solid tumour samples illustrates the discovery of subgroups from GT genes that match well against basal-like and HER2-enriched subtypes and correlates to clinical, mutation and survival data. This cancer type glycosyltransferase gene signature finding provides foundational evidence for the centrality of glycosylation in cancer.

Identification and functional characterization of a flax UDP-glycosyltransferase glucosylating secoisolariciresinol (SECO) into secoisolariciresinol monoglucoside (SMG) and diglucoside (SDG).

Science.gov (United States)

Ghose, Kaushik; Selvaraj, Kumarakurubaran; McCallum, Jason; Kirby, Chris W; Sweeney-Nixon, Marva; Cloutier, Sylvie J; Deyholos, Michael; Datla, Raju; Fofana, Bourlaye

2014-03-28

Lignans are a class of diphenolic nonsteroidal phytoestrogens often found glycosylated in planta. Flax seeds are a rich source of secoisolariciresinol diglucoside (SDG) lignans. Glycosylation is a process by which a glycosyl group is covalently attached to an aglycone substrate and is catalyzed by uridine diphosphate glycosyltransferases (UGTs). Until now, very little information was available on UGT genes that may play a role in flax SDG biosynthesis. Here we report on the identification, structural and functional characterization of 5 putative UGTs potentially involved in secoisolariciresinol (SECO) glucosylation in flax. Five UGT genes belonging to the glycosyltransferases' family 1 (EC 2.4.x.y) were cloned and characterized. They fall under four UGT families corresponding to five sub-families referred to as UGT74S1, UGT74T1, UGT89B3, UGT94H1, UGT712B1 that all display the characteristic plant secondary product glycosyltransferase (PSPG) conserved motif. However, diversity was observed within this 44 amino acid sequence, especially in the two peptide sequences WAPQV and HCGWNS known to play a key role in the recognition and binding of diverse aglycone substrates and in the sugar donor specificity. In developing flax seeds, UGT74S1 and UGT94H1 showed a coordinated gene expression with that of pinoresinol-lariciresinol reductase (PLR) and their gene expression patterns correlated with SDG biosynthesis. Enzyme assays of the five heterologously expressed UGTs identified UGT74S1 as the only one using SECO as substrate, forming SECO monoglucoside (SMG) and then SDG in a sequential manner. We have cloned and characterized five flax UGTs and provided evidence that UGT74S1 uses SECO as substrate to form SDG in vitro. This study allowed us to propose a model for the missing step in SDG lignan biosynthesis.

Functional Characterization of a Flavonoid Glycosyltransferase in Sweet Orange (Citrus sinensis).

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Liu, Xiaogang; Lin, Cailing; Ma, Xiaodi; Tan, Yan; Wang, Jiuzhao; Zeng, Ming

2018-01-01

Fruits of sweet orange ( Citrus sinensis ), a popular commercial Citrus species, contain high concentrations of flavonoids beneficial to human health. These fruits predominantly accumulate O -glycosylated flavonoids, in which the disaccharides [neohesperidose (rhamnosyl-α-1,2-glucose) or rutinose (rhamnosyl-α-1,6-glucose)] are linked to the flavonoid aglycones through the 3- or 7-hydroxyl sites. The biotransformation of the flavonoid aglycones into O -rutinosides or O -neohesperidosides in the Citrus plants usually consists of two glycosylation reactions involving a series of uridine diphosphate-sugar dependent glycosyltransferases (UGTs). Although several genes encoding flavonoid UGTs have been functionally characterized in the Citrus plants, full elucidation of the flavonoid glycosylation process remains elusive. Based on the available genomic and transcriptome data, we isolated a UGT with a high expression level in the sweet orange fruits that possibly encodes a flavonoid glucosyltransferase and/or rhamnosyltransferase. Biochemical analyses revealed that a broad range of flavonoid substrates could be glucosylated at their 3- and/or 7-hydrogen sites by the recombinant enzyme, including hesperetin, naringenin, diosmetin, quercetin, and kaempferol. Furthermore, overexpression of the gene could significantly increase the accumulations of quercetin 7- O -rhamnoside, quercetin 7- O -glucoside, and kaempferol 7- O -glucoside, implying that the enzyme has flavonoid 7- O -glucosyltransferase and 7- O -rhamnosyltransferase activities in vivo .

Reassessment of acarbose as a transition state analogue inhibitor of cyclodextrin glycosyltransferase

NARCIS (Netherlands)

Mosi, Renee; Sham, Howard; Uitdehaag, Joost C.M.; Ruiterkamp, Richard; Dijkstra, Bauke W.; Withers, Stephen G.

1998-01-01

The binding of several different active site mutants of Bacillus circulans cyclodextrin,glycosyltransferase to the inhibitor acarbose has been investigated through measurement of Ki values. The mutations represent several key amino acid positions, most of which are believed to play important roles

Plant glyco-biotechnology on the way to synthetic biology

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Andreas eLoos

2014-10-01

Full Text Available Plants are increasingly being used for the production of recombinant proteins. One reason is that plants are highly amenable for glycan engineering processes and allow the production of therapeutic proteins with increased efficacies due to optimized glycosylation profiles. Removal and insertion of glycosylation reactions by knock-out/knock-down approaches and introduction of glycosylation enzymes have paved the way for the humanization of the plant glycosylation pathway. The insertion of heterologous enzymes at exactly the right stage of the existing glycosylation pathway has turned out to be of utmost importance for optimal results. To enable such precise targeting chimeric enzymes have been constructed. In this short review we will exemplify the importance of correct targeting of glycosyltransferases, we will give an overview of the targeting mechanism of glycosyltransferases, describe chimeric enzymes used in plant N-glycosylation engineering and illustrate how plant glycoengineering builds on the tools offered by synthetic biology to construct such chimeric enzymes.

An iterative glycosyltransferase EntS catalyzes transfer and extension of O- and S-linked monosaccharide in enterocin 96.

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Nagar, Rupa; Rao, Alka

2017-05-12

Glycosyltransferases are essential tools for in vitro-glycoengineering. Bacteria harbor an unexplored variety of protein glycosyltransferases. Here, we describe a peptide glycosyltransferase (EntS) encoded by ORF0417 of Enterococcus faecalis TX0104. EntS di-glycosylates linear peptide of enterocin 96- a known antibacterial, in vitro. It is capable of transferring as well as extending the glycan onto the peptide in an iterative sequential dissociative manner. It can catalyze multiple linkages: Glc/Gal(-O)Ser/Thr, Glc/Gal(-S)Cys and Glc/Gal(β)Glc/Gal(-O/S)Ser/Thr/Cys, in one pot. Using EntS generated glycovariants of enterocin 96 peptide, size and identity of the glycan are found to influence bioactivity of the peptide. The study identifies EntS as an enzyme worth pursuing, for in vitro peptide glycoengineering. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The Arabidopsis UDP-glycosyltransferases UGT79B2 and UGT79B3, contribute to cold, salt and drought stress tolerance via modulating anthocyanin accumulation.

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Li, Pan; Li, Yan-Jie; Zhang, Feng-Ju; Zhang, Gui-Zhi; Jiang, Xiao-Yi; Yu, Hui-Min; Hou, Bing-Kai

2017-01-01

The plant family 1 UDP-glycosyltransferases (UGTs) are the biggest GT family in plants, which are responsible for transferring sugar moieties onto a variety of small molecules, and control many metabolic processes; however, their physiological significance in planta is largely unknown. Here, we revealed that two Arabidopsis glycosyltransferase genes, UGT79B2 and UGT79B3, could be strongly induced by various abiotic stresses, including cold, salt and drought stresses. Overexpression of UGT79B2/B3 significantly enhanced plant tolerance to low temperatures as well as drought and salt stresses, whereas the ugt79b2/b3 double mutants generated by RNAi (RNA interference) and CRISPR-Cas9 strategies were more susceptible to adverse conditions. Interestingly, the expression of UGT79B2 and UGT79B3 is directly controlled by CBF1 (CRT/DRE-binding factor 1, also named DREB1B) in response to low temperatures. Furthermore, we identified the enzyme activities of UGT79B2/B3 in adding UDP-rhamnose to cyanidin and cyanidin 3-O-glucoside. Ectopic expression of UGT79B2/B3 significantly increased the anthocyanin accumulation, and enhanced the antioxidant activity in coping with abiotic stresses, whereas the ugt79b2/b3 double mutants showed reduced anthocyanin levels. When overexpressing UGT79B2/B3 in tt18 (transparent testa 18), a mutant that cannot synthesize anthocyanins, both genes fail to improve plant adaptation to stress. Taken together, we demonstrate that UGT79B2 and UGT79B3, identified as anthocyanin rhamnosyltransferases, are regulated by CBF1 and confer abiotic stress tolerance via modulating anthocyanin accumulation. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Glycosyltransferase family 43 is also found in early eukaryotes and has three subfamilies in Charophycean green algae.

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Rahil Taujale

Full Text Available The glycosyltransferase family 43 (GT43 has been suggested to be involved in the synthesis of xylans in plant cell walls and proteoglycans in animals. Very recently GT43 family was also found in Charophycean green algae (CGA, the closest relatives of extant land plants. Here we present evidence that non-plant and non-animal early eukaryotes such as fungi, Haptophyceae, Choanoflagellida, Ichthyosporea and Haptophyceae also have GT43-like genes, which are phylogenetically close to animal GT43 genes. By mining RNA sequencing data (RNA-Seq of selected plants, we showed that CGA have evolved three major groups of GT43 genes, one orthologous to IRX14 (IRREGULAR XYLEM14, one orthologous to IRX9/IRX9L and the third one ancestral to all land plant GT43 genes. We confirmed that land plant GT43 has two major clades A and B, while in angiosperms, clade A further evolved into three subclades and the expression and motif pattern of A3 (containing IRX9 are fairly different from the other two clades likely due to rapid evolution. Our in-depth sequence analysis contributed to our overall understanding of the early evolution of GT43 family and could serve as an example for the study of other plant cell wall-related enzyme families.

Formation of flavone di-O-glucosides using a glycosyltransferase from Bacillus cereus.

Science.gov (United States)

Ahn, Byoung Chan; Kim, Bong Gyu; Jeon, Young Min; Lee, Eun Jeong; Lim, Yoongho; Ahn, Joong-Hoon

2009-04-01

Microbial UDP-glycosyltransferases can convert many small lipophilic compounds into glycons using uridinediphosphate- activated sugars. The glycosylation of flavonoids affects solubility, stability, and bioavailability. The gene encoding the UDP-glycosyltransferase from Bacillus cereus, BcGT-3, was cloned by PCR and sequenced. BcGT-3 was expressed in Escherichia coli BL21 (DE3) with a glutathione S-transferase tag and purified using a glutathione Stransferase affinity column. BcGT-3 was tested for activity on several substrates including genistein, kaempferol, luteolin, naringenin, and quercetin. Flavonols were the best substrates for BcGT-3. The enzyme dominantly glycosylated the 3-hydroxyl group, but the 7-hydroxyl group was glycosylated when the 3-hydroxyl group was not available. The kaempferol reaction products were identified as kaempferol-3-O-glucoside and kaempferol- 3,7-O-diglucoside. Kaempferol was the most effective substrate tested. Based on HPLC, LC/MS, and NMR analyses of the reaction products, we conclude that BcGT-3 can be used for the synthesis of kaempferol 3,7-O-diglucose.

Classification, Naming and Evolutionary History of Glycosyltransferases from Sequenced Green and Red Algal Genomes

DEFF Research Database (Denmark)

Ulvskov, Peter; Paiva, Dionisio Soares; Domozych, David

2013-01-01

. In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated. Fully sequenced genomes from the Rhodophyta and Virideplantae and the well-defined CAZy database on glycosyltransferases were included in the analysis. The number...

Bacterial origin of a diverse family of UDP-glycosyltransferase genes in the Tetranychus urticae genome

NARCIS (Netherlands)

Ahn, S.J.; Dermauw, W.; Wybouw, N.; Heckel, D.G.; Van Leeuwen, T.

2014-01-01

UDP-glycosyltransferases (UGTs) catalyze the conjugation of a variety of small lipophilic molecules with uridine diphosphate (UDP) sugars, altering them into more water-soluble metabolites. Thereby, UGTs play an important role in the detoxification of xenobiotics and in the regulation of

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

Energy Technology Data Exchange (ETDEWEB)

Fulton, Zara [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Crellin, Paul K.; Brammananth, Rajini [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Zaker-Tabrizi, Leyla [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Coppel, Ross L. [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Rossjohn, Jamie, E-mail: jamie.rossjohn@med.monash.edu.au; Beddoe, Travis, E-mail: jamie.rossjohn@med.monash.edu.au [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia)

2008-05-01

MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

International Nuclear Information System (INIS)

Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohn, Jamie; Beddoe, Travis

2008-01-01

MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4 1 2 1 2

Radiosensitivity of higher plants

International Nuclear Information System (INIS)

Feng Zhijie

1992-11-01

The general views on radiosensitivity of higher plants have been introduced from published references. The radiosensitivity varies with species, varieties and organs or tissues. The main factors of determining the radiosensitivity in different species are nucleus volume, chromosome volume, DNA content and endogenous compounds. The self-repair ability of DNA damage and chemical group of biological molecules, such as -SH thiohydroxy of proteins, are main factors to determine the radiosensitivity in different varieties. The moisture, oxygen, temperature radiosensitizer and protector are important external factors for radiosensitivity. Both the multiple target model and Chadwick-Leenhouts model are ideal mathematical models for describing the radiosensitivity of higher plants and the latter has more clear significance in biology

The three transglycosylation reactions catalyzed by cyclodextrin glycosyltransferase from Bacillus circulans (strain 251) proceed via different kinetic mechanisms

NARCIS (Netherlands)

Veen, Bart A. van der; Alebeek, Gert-Jan W.M. van; Uitdehaag, Joost C.M.; Dijkstra, Bauke W.; Dijkhuizen, Lubbert

Cyclodextrin glycosyltransferase (CGTase) catalyzes three transglycosylation reactions via a double displacement mechanism involving a covalent enzyme-intermediate complex (substituted-enzyme intermediate). Characterization of the three transglycosylation reactions, however, revealed that they

Glycosyltransferases and non-alcoholic fatty liver disease

Science.gov (United States)

Zhan, Yu-Tao; Su, Hai-Ying; An, Wei

2016-01-01

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease and its incidence is increasing worldwide. However, the underlying mechanisms leading to the development of NAFLD are still not fully understood. Glycosyltransferases (GTs) are a diverse class of enzymes involved in catalyzing the transfer of one or multiple sugar residues to a wide range of acceptor molecules. GTs mediate a wide range of functions from structure and storage to signaling, and play a key role in many fundamental biological processes. Therefore, it is anticipated that GTs have a role in the pathogenesis of NAFLD. In this article, we present an overview of the basic information on NAFLD, particularly GTs and glycosylation modification of certain molecules and their association with NAFLD pathogenesis. In addition, the effects and mechanisms of some GTs in the development of NAFLD are summarized. PMID:26937136

Novel staphylococcal glycosyltransferases SdgA and SdgB mediate immunogenicity and protection of virulence-associated cell wall proteins.

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Wouter L W Hazenbos

Full Text Available Infection of host tissues by Staphylococcus aureus and S. epidermidis requires an unusual family of staphylococcal adhesive proteins that contain long stretches of serine-aspartate dipeptide-repeats (SDR. The prototype member of this family is clumping factor A (ClfA, a key virulence factor that mediates adhesion to host tissues by binding to extracellular matrix proteins such as fibrinogen. However, the biological siginificance of the SDR-domain and its implication for pathogenesis remain poorly understood. Here, we identified two novel bacterial glycosyltransferases, SdgA and SdgB, which modify all SDR-proteins in these two bacterial species. Genetic and biochemical data demonstrated that these two glycosyltransferases directly bind and covalently link N-acetylglucosamine (GlcNAc moieties to the SDR-domain in a step-wise manner, with SdgB appending the sugar residues proximal to the target Ser-Asp repeats, followed by additional modification by SdgA. GlcNAc-modification of SDR-proteins by SdgB creates an immunodominant epitope for highly opsonic human antibodies, which represent up to 1% of total human IgG. Deletion of these glycosyltransferases renders SDR-proteins vulnerable to proteolysis by human neutrophil-derived cathepsin G. Thus, SdgA and SdgB glycosylate staphylococcal SDR-proteins, which protects them against host proteolytic activity, and yet generates major eptopes for the human anti-staphylococcal antibody response, which may represent an ongoing competition between host and pathogen.

Sucrose synthase: A unique glycosyltransferase for biocatalytic glycosylation process development.

Science.gov (United States)

Schmölzer, Katharina; Gutmann, Alexander; Diricks, Margo; Desmet, Tom; Nidetzky, Bernd

2016-01-01

Sucrose synthase (SuSy, EC 2.4.1.13) is a glycosyltransferase (GT) long known from plants and more recently discovered in bacteria. The enzyme catalyzes the reversible transfer of a glucosyl moiety between fructose and a nucleoside diphosphate (NDP) (sucrose+NDP↔NDP-glucose+fructose). The equilibrium for sucrose conversion is pH dependent, and pH values between 5.5 and 7.5 promote NDP-glucose formation. The conversion of a bulk chemical to high-priced NDP-glucose in a one-step reaction provides the key aspect for industrial interest. NDP-sugars are important as such and as key intermediates for glycosylation reactions by highly selective Leloir GTs. SuSy has gained renewed interest as industrially attractive biocatalyst, due to substantial scientific progresses achieved in the last few years. These include biochemical characterization of bacterial SuSys, overproduction of recombinant SuSys, structural information useful for design of tailor-made catalysts, and development of one-pot SuSy-GT cascade reactions for production of several relevant glycosides. These advances could pave the way for the application of Leloir GTs to be used in cost-effective processes. This review provides a framework for application requirements, focusing on catalytic properties, heterologous enzyme production and reaction engineering. The potential of SuSy biocatalysis will be presented based on various biotechnological applications: NDP-sugar synthesis; sucrose analog synthesis; glycoside synthesis by SuSy-GT cascade reactions. Copyright © 2015 Elsevier Inc. All rights reserved.

SIGNIFICANCE OF GALACTINOL AND RAFFINOSE FAMILY OLIGOSACCHARIDE SYNTHESIS IN PLANTS

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Sonali eSengupta

2015-08-01

Full Text Available Abiotic stress induces differential expression of genes responsible for the synthesis of Raffinose series of Oligosaccharides (RFOs in plants. RFOs are described as the most widespread D-galactose containing oligosaccharides in higher plants. Biosynthesis of RFOs begin with the activity of Galactinol synthase (GolS; EC 2.4.1.123, a GT8 family glycosyltransferase that galactosylates myo-inositol to produce galactinol. Raffinose and the subsequent higher molecular weight RFOs (Stachyose, Verbascose and Ajugose are synthesized from sucrose by the subsequent addition of activated galactose moieties donated by Galactinol. Interestingly, GolS, the key enzyme of this pathway is functional only in the flowering plants. It is thus assumed that RFO synthesis is a specialized metabolic event in higher plants; although it is not known whether lower plant groups synthesize any galactinol or RFOs. In higher plants, several functional importance of RFOs have been reported, e.g. RFOs protect the embryo from maturation associated desiccation, are predominant transport carbohydrate in some plant families, act as signaling molecule following pathogen attack and wounding and accumulate in vegetative tissues in response to a range of abiotic stresses. However, the loss-of-function mutants reported so far fail to show any perturbation in those biological functions. The role of RFOs in biotic and abiotic stress is therefore still in debateand their specificity and related components remains to be demonstrated. The present review discusses the biology and stress-linked regulation of this less studied extension of inositol metabolic pathway.

The Arabidopsis Family GT43 Glycosyltransferases Form Two Functionally Nonredundant Groups Essential for the Elongation of Glucuronoxylan Backbone

Science.gov (United States)

There exist four members of family GT43 glycosyltransferases in the Arabidopsis (Arabidopsis thaliana) genome, and mutations of two of them, IRX9 and IRX14, have previously been shown to cause a defect in glucuronoxylan (GX) biosynthesis. However, it is currently unknown whether ...

Regulation of plant cells, cell walls and development by mechanical signals

Energy Technology Data Exchange (ETDEWEB)

Meyerowitz, Elliot M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

2016-06-14

The overall goal of the revised scope of work for the final year of funding was to characterize cell wall biosynthesis in developing cotyledons and in the shoot apical meristem of Arabidopsis thaliana, as a way of learning about developmental control of cell wall biosynthesis in plants, and interactions between cell wall biosynthesis and the microtubule cytoskeleton. The proposed work had two parts – to look at the effect of mutation in the SPIRAL2 gene on microtubule organization and reorganization, and to thoroughly characterize the glycosyltransferase genes expressed in shoot apical meristems by RNA-seq experiments, by in situ hybridization of the RNAs expressed in the meristem, and by antibody staining of the products of the glycosyltransferases in meristems. Both parts were completed; the spiral2 mutant was found to speed microtubule reorientation after ablation of adjacent cells, supporting our hypothesis that reorganization correlates with microtubule severing, the rate of which is increased by the mutation. The glycosyltransferase characterization was completed and published as Yang et al. (2016). Among the new things learned was that primary cell wall biosynthesis is strongly controlled both by cell type, and by stage of cell cycle, implying not only that different, even adjacent, cells can have different sugar linkages in their (nonshared) walls, but also that a surprisingly large proportion of glycosyltransferases is regulated in the cell cycle, and therefore that the cell cycle regulates wall maturation to a degree previously unrecognized.

Tomato UDP-Glucose Sterol Glycosyltransferases: A Family of Developmental and Stress Regulated Genes that Encode Cytosolic and Membrane-Associated Forms of the Enzyme

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Karla Ramirez-Estrada

2017-06-01

Full Text Available Sterol glycosyltransferases (SGTs catalyze the glycosylation of the free hydroxyl group at C-3 position of sterols to produce sterol glycosides. Glycosylated sterols and free sterols are primarily located in cell membranes where in combination with other membrane-bound lipids play a key role in modulating their properties and functioning. In contrast to most plant species, those of the genus Solanum contain very high levels of glycosylated sterols, which in the case of tomato may account for more than 85% of the total sterol content. In this study, we report the identification and functional characterization of the four members of the tomato (Solanum lycopersicum cv. Micro-Tom SGT gene family. Expression of recombinant SlSGT proteins in E. coli cells and N. benthamiana leaves demonstrated the ability of the four enzymes to glycosylate different sterol species including cholesterol, brassicasterol, campesterol, stigmasterol, and β-sitosterol, which is consistent with the occurrence in their primary structure of the putative steroid-binding domain found in steroid UDP-glucuronosyltransferases and the UDP-sugar binding domain characteristic for a superfamily of nucleoside diphosphosugar glycosyltransferases. Subcellular localization studies based on fluorescence recovery after photobleaching and cell fractionation analyses revealed that the four tomato SGTs, like the Arabidopsis SGTs UGT80A2 and UGT80B1, localize into the cytosol and the PM, although there are clear differences in their relative distribution between these two cell fractions. The SlSGT genes have specialized but still largely overlapping expression patterns in different organs of tomato plants and throughout the different stages of fruit development and ripening. Moreover, they are differentially regulated in response to biotic and abiotic stress conditions. SlSGT4 expression increases markedly in response to osmotic, salt, and cold stress, as well as upon treatment with abscisic

Cellulose biosynthesis in higher plants

Directory of Open Access Journals (Sweden)

Krystyna Kudlicka

2014-01-01

Full Text Available Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. In vivo, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable in vitro assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the in vitro product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

Shifted Golgi targeting of glycosyltransferases and α-mannosidase IA from giantin to GM130-GRASP65 results in formation of high mannose N-glycans in aggressive prostate cancer cells.

Science.gov (United States)

Bhat, Ganapati; Hothpet, Vishwanath-Reddy; Lin, Ming-Fong; Cheng, Pi-Wan

2017-11-01

There is a pressing need for biomarkers that can distinguish indolent from aggressive prostate cancer to prevent over-treatment of patients with indolent tumor. Golgi targeting of glycosyltransferases was characterized by confocal microscopy after knockdown of GM130, giantin, or both. N-glycans on a trans-Golgi enzyme β4galactosyltransferase-1 isolated by immunoprecipitation from androgen-sensitive and independent prostate cancer cells were determined by matrix-assisted laser desorption-time of flight-mass spectrometry. In situ proximity ligation assay was employed to determine co-localization of (a) α-mannosidase IA, an enzyme required for processing Man 8 GlcNAc 2 down to Man 5 GlcNAc 2 to enable synthesis of complex-type N-glycans, with giantin, GM130, and GRASP65, and (b) trans-Golgi glycosyltransferases with high mannose N-glycans terminated with α3-mannose. Defective giantin in androgen-independent prostate cancer cells results in a shift of Golgi targeting of glycosyltransferases and α-mannosidase IA from giantin to GM130-GRASP65. Consequently, trans-Golgi enzymes and cell surface glycoproteins acquire high mannose N-glycans, which are absent in cells with functional giantin. In situ proximity ligation assays of co-localization of α-mannosidase IA with GM130 and GRASP65, and trans-Golgi glycosyltransferases with high mannose N-glycans are negative in androgen-sensitive LNCaP C-33 cells but positive in androgen-independent LNCaP C-81 and DU145 cells, and LNCaP C-33 cells devoid of giantin. In situ proximity ligation assays of Golgi localization of α-mannosidase IA at giantin versus GM130-GRASP65 site, and absence or presence of N-glycans terminated with α3-mannose on trans-Golgi glycosyltransferases may be useful for distinguishing indolent from aggressive prostate cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of RbmD (glycosyltransferase in ribostamycin gene cluster) through neomycin production reconstituted from the engineered Streptomyces fradiae BS1.

Science.gov (United States)

Nepal, Keshav Kumar; Oh, Tae-Jin; Subba, Bimala; Yoo, Jin Cheol; Sohng, Jae Kyung

2009-01-31

Amino acid homology analysis predicted that rbmD, a putative glycosyltransferase from Streptomyces ribosidificus ATCC 21294, has the highest homology with neoD in neomycin biosynthesis. S. fradiae BS1, in which the production of neomycin was abolished, was generated by disruption of the neoD gene in the neomycin producer S. fradiae. The restoration of neomycin by self complementation suggested that there was no polar effect in the mutant. In addition, S. fradiae BS6 was created with complementation by rbmD in S. fradiae BS1, and secondary metabolite analysis by ESI/MS, LC/MS and MS/MS showed the restoration of neomycin production in S. fradiae BS6. These gene inactivation and complementation studies suggested that, like neoD, rbmD functions as a 2-N-acetlyglucosaminyltransferase and demonstrated the potential for the generation of novel aminoglycoside antibiotics using glycosyltransferases in vivo.

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

Energy Technology Data Exchange (ETDEWEB)

Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohna, Jamie; Beddoe, Travis (Monash)

2008-05-28

Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 {angstrom} resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

Assimilation and transformation of benzene by higher plants

Energy Technology Data Exchange (ETDEWEB)

Durmishidze, S V; Ugrekhelidze, D Sh; Dzhikiya, A N

1974-01-01

Higher plants are capable of assimilating benzene, the molecules of which are subjected to deep chemical transformations; the products of its metabolism move along the plant. Taking part in total metabolism, carbon atoms of benzene molecules incorporate into composition of low-molecular compounds of the plant cell. The bulk of benzene carbon incorporates into composition of organic acids and a comparatively small part - into composition of amino acids. In the metabolism process benzene carbon localizes mainly in the chloroplasts. Phenol, muconic acid and CO/sub 2/ are isolated and identified from the products of benzene enzymatic oxidation. A range of benzene assimilation by higher plants is extremely wide. 9 references, 5 tables.

Expression and Purification of Glycosyltransferases in Pichia Pastoris: Towards Improving the Migration of Stem Cells by Enhancing Surface Expression of Sialyl Lewis X

KAUST Repository

Al-Amoodi, Asma S.

2017-01-01

Recruitment of circulating cells towards target sites is primarily dependent on E-selectin receptor/ligand adhesive interactions. Glycosyltransferase (GTs) are involved in the creation of E-selectin ligands. A sialofucosylated terminal

Differences in glycosyltransferase family 61 accompany variation in seed coat mucilage composition in Plantago spp.

Science.gov (United States)

Phan, Jana L.; Tucker, Matthew R.; Khor, Shi Fang; Shirley, Neil; Lahnstein, Jelle; Beahan, Cherie; Bacic, Antony; Burton, Rachel A.

2016-01-01

Xylans are the most abundant non-cellulosic polysaccharide found in plant cell walls. A diverse range of xylan structures influence tissue function during growth and development. Despite the abundance of xylans in nature, details of the genes and biochemical pathways controlling their biosynthesis are lacking. In this study we have utilized natural variation within the Plantago genus to examine variation in heteroxylan composition and structure in seed coat mucilage. Compositional assays were combined with analysis of the glycosyltransferase family 61 (GT61) family during seed coat development, with the aim of identifying GT61 sequences participating in xylan backbone substitution. The results reveal natural variation in heteroxylan content and structure, particularly in P. ovata and P. cunninghamii, species which show a similar amount of heteroxylan but different backbone substitution profiles. Analysis of the GT61 family identified specific sequences co-expressed with IRREGULAR XYLEM 10 genes, which encode putative xylan synthases, revealing a close temporal association between xylan synthesis and substitution. Moreover, in P. ovata, several abundant GT61 sequences appear to lack orthologues in P. cunninghamii. Our results indicate that natural variation in Plantago species can be exploited to reveal novel details of seed coat development and polysaccharide biosynthetic pathways. PMID:27856710

Effects of genetic modifications to flax (Linum usitatissimum) on arbuscular mycorrhiza and plant performance.

Science.gov (United States)

Wróbel-Kwiatkowska, Magdalena; Turnau, Katarzyna; Góralska, Katarzyna; Anielska, Teresa; Szopa, Jan

2012-10-01

Although arbuscular mycorrhizal fungi (AMF) are known for their positive effect on flax growth, the impact of genetic manipulation in this crop on arbuscular mycorrhiza and plant performance was assessed for the first time. Five types of transgenic flax that were generated to improve fiber quality and resistance to pathogens, through increased levels of either phenylpropanoids (W92.40), glycosyltransferase (GT4, GT5), or PR2 beta-1,3-glucanase (B14) or produce polyhydroxybutyrate (M50), were used. Introduced genetic modifications did not change the degree of mycorrhizal colonization as compared to parent cultivars Linola and Nike. Arbuscules were well developed in each tested transgenic type (except M50). In two lines (W92.40 and B14), a higher abundance of arbuscules was observed when compared to control, untransformed flax plants. However, in some cases (W92.40, GT4, GT5, and B14 Md), the mycorrhizal dependency for biomass production of transgenic plants was slightly lower when compared to the original cultivars. No significant influence of mycorrhiza on the photosynthetic activity of transformed lines was found, but in most cases P concentration in mycorrhizal plants remained higher than in nonmycorrhizal ones. The transformed flax lines meet the demands for better quality of fiber and higher resistance to pathogens, without significantly influencing the interaction with AMF.

Potential physiological role of plant glycosidase inhibitors

DEFF Research Database (Denmark)

Bellincampi, D.; Carmadella, L.; Delcour, J.A.

2004-01-01

Carbohydrate-active enzymes including glycosidases, transglycosidases, glycosyltransferases, polysaccharide lyases and carbohydrate esterases are responsible for the enzymatic processing of carbohydrates in plants. A number of carbohydrate-active enzymes are produced by microbial pathogens...... and insects responsible of severe crop losses. Plants have evolved proteinaceous inhibitors to modulate the activity of several of these enzymes. The continuing discovery of new inhibitors indicates that this research area is still unexplored and may lead to new exciting developments. To date, the role...... of the inhibitors is not completely understood. Here we review recent results obtained on the best characterised inhibitors, pointing to their possible biological role in vivo. Results recently obtained with plant transformation technology indicate that this class of inhibitors has potential biotechnological...

Structural characterization of O- and C-glycosylating variants of the landomycin glycosyltransferase LanGT2.

Science.gov (United States)

Tam, Heng Keat; Härle, Johannes; Gerhardt, Stefan; Rohr, Jürgen; Wang, Guojun; Thorson, Jon S; Bigot, Aurélien; Lutterbeck, Monika; Seiche, Wolfgang; Breit, Bernhard; Bechthold, Andreas; Einsle, Oliver

2015-02-23

The structures of the O-glycosyltransferase LanGT2 and the engineered, C-C bond-forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide-sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced-fit transition was explored by molecular docking experiments with various aglycon substrates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromosomal replicons of higher plants

International Nuclear Information System (INIS)

Van't Hof, J.

1987-01-01

This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs

Identification and characterization of glycosyltransferases involved in the synthesis of the side chains of the cell wall pectic polysaccharide rhamnogalacturonan II

Energy Technology Data Exchange (ETDEWEB)

O' Neill, Malcolm [Univ. of Georgia, Athens, GA (United States)

2015-08-31

Our goal was to gain insight into the genes and proteins involved in the biosynthesis of rhamnogalacturonan II (RG-II), a borate cross-linked and structurally conserved pectic polysaccharide present in the primary cell walls of all vascular plants. The research conducted during the funding period established that (i) Avascular plants have the ability to synthesize UDP-apiose but lack the glycosyltransferase machinery required to synthesize RG-II or other apiose-containing cell wall glycans. (ii) RG-II structure is highly conserved in the Lemnaceae (duckweeds and relatives). However, the structures of other wall pectins and hemicellulose have changed substantial during the diversification of the Lemnaceae. This supports the notion that a precise structure of RG-II must be maintained to allow borate cross-linking to occur in a controlled manner. (iii) Enzymes involved in the conversion of UDP-GlcA to UDP-Api, UDP-Xyl, and UDP-Ara may have an important role in controlling the composition of duckweed cell walls. (iv) RG-II exists as the borate ester cross-linked dimer in the cell walls of soybean root hairs and roots. Thus, RG-II is present in the walls of plants cells that grow by tip or by expansive growth. (v) A reduction in RG-II cross-linking in the maize tls1 mutant, which lacks a borate channel protein, suggests that the growth defects observed in the mutant are, at least in part, due to defects in the cell wall.

Role of Glycosyltransferases Modifying Type B Flagellin of Emerging Hypervirulent Clostridium difficile Lineages and Their Impact on Motility and Biofilm Formation*

Science.gov (United States)

Valiente, Esmeralda; Bouché, Laura; Hitchen, Paul; Faulds-Pain, Alexandra; Songane, Mario; Dawson, Lisa F.; Donahue, Elizabeth; Stabler, Richard A.; Panico, Maria; Morris, Howard R.; Bajaj-Elliott, Mona; Logan, Susan M.; Dell, Anne; Wren, Brendan W.

2016-01-01

Clostridium difficile is the principal cause of nosocomial infectious diarrhea worldwide. The pathogen modifies its flagellin with either a type A or type B O-linked glycosylation system, which has a contributory role in pathogenesis. We study the functional role of glycosyltransferases modifying type B flagellin in the 023 and 027 hypervirulent C. difficile lineages by mutagenesis of five putative glycosyltransferases and biosynthetic genes. We reveal their roles in the biosynthesis of the flagellin glycan chain and demonstrate that flagellar post-translational modification affects motility and adhesion-related bacterial properties of these strains. We show that the glycosyltransferases 1 and 2 (GT1 and GT2) are responsible for the sequential addition of a GlcNAc and two rhamnoses, respectively, and that GT3 is associated with the incorporation of a novel sulfonated peptidyl-amido sugar moiety whose structure is reported in our accompanying paper (Bouché, L., Panico, M., Hitchen, P., Binet, D., Sastre, F., Faulds-Pain, A., Valiente, E., Vinogradov, E., Aubry, A., Fulton, K., Twine, S., Logan, S. M., Wren, B. W., Dell, A., and Morris, H. R. (2016) J. Biol. Chem. 291, 25439–25449). GT2 is also responsible for methylation of the rhamnoses. Whereas type B modification is not required for flagellar assembly, some mutations that result in truncation or abolition of the glycan reduce bacterial motility and promote autoaggregation and biofilm formation. The complete lack of flagellin modification also significantly reduces adhesion of C. difficile to Caco-2 intestinal epithelial cells but does not affect activation of human TLR5. Our study advances our understanding of the genes involved in flagellar glycosylation and their biological roles in emerging hypervirulent C. difficile strains. PMID:27703012

Ecological Risk Assessment of Genetically Modified Higher Plants (GMHP)

DEFF Research Database (Denmark)

Kjær, C.; Damgaard, C.; Kjellsson, G.

Preface This publication is a first version of a manual identifying the data needs for ecological risk assessment of genetically modified higher plants (GMHP). It is the intention of the authors to stimulate further discussion of what data are needed in order to conduct a proper ecological risk...... of the project Biotechnology: elements in environmental risk assessment of genetically modified plants. December 1999 Christian Kjær Introduction In ecological risk assessment of transgenic plants, information on a wide range of subjects is needed for an effective and reliable assessment procedure...... in the amendment to the directive. This report suggests a structured way to identify the type of data needed to perform a sound ecological risk assessment for genetically modified higher plants (GMHP). The identified data types are intended to support the evaluation of the following risks: risk of invasion...

Computational identification of candidate nucleotide cyclases in higher plants

KAUST Repository

Wong, Aloysius Tze

2013-09-03

In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs are often part of complex multifunctional proteins with different domain organizations and biological functions that are not conserved in higher plants. For this reason, we have developed CNC search strategies based on functionally conserved amino acids in the catalytic center of annotated and/or experimentally confirmed CNCs. Here we detail this method which has led to the identification of >25 novel candidate CNCs in Arabidopsis thaliana, several of which have been experimentally confirmed in vitro and in vivo. We foresee that the application of this method can be used to identify many more members of the growing family of CNCs in higher plants. © Springer Science+Business Media New York 2013.

Glycosyltransferases as marker genes for the quantitative polymerase chain reaction-based detection of circulating tumour cells from blood samples of patients with breast cancer undergoing adjuvant therapy.

Science.gov (United States)

Kölbl, Alexandra C; Hiller, Roman A; Ilmer, Mathias; Liesche, Friederike; Heublein, Sabine; Schröder, Lennard; Hutter, Stefan; Friese, Klaus; Jeschke, Udo; Andergassen, Ulrich

2015-08-01

Altered glycosylation is a predominant feature of tumour cells; it serves for cell adhesion and detachment, respectively, and facilitates the immune escape of these cells. Therefore changes in the expression of glycosyltransferase genes could help to identify circulating tumour cells (CTCs) in the blood samples of cancer patients using a quantitative polymerase chain reaction (PCR) approach. Blood samples of healthy donors were inoculated with certain numbers of established breast cancer cell line cells, thus creating a model system. These samples were analysed by quantitative PCR for the expression of six different glycosyltransferase genes. The three genes with the best results in the model system were consecutively applied to samples from adjuvant breast cancer patients and of healthy donors. FUT3 and GALNT6 showed the highest increase in relative expression, while GALNT6 and ST3GAL3 were the first to reach statistically significant different ∆CT-values comparing the sample with and without addition of tumour cells. These three genes were applied to patient samples, but did not show any significant results that may suggest the presence of CTCs in the blood. Although the relative expression of some of the glycosyltransferase genes exhibited reasonable results in the model system, their application to breast cancer patient samples will have to be further improved, e.g. by co-analysis of patient blood samples by gold-standard methods.

Higher Plants in Space: Microgravity Perception, Response, and Adaptation

Science.gov (United States)

Zheng, Hui Qiong; Han, Fei; Le, Jie

2015-11-01

Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

Chlorine-containing natural compounds in higher plants

DEFF Research Database (Denmark)

Engvild, Kjeld Christensen

1986-01-01

More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

Science.gov (United States)

Mishra, Manoj K.; Chaturvedi, Pankaj; Singh, Ruchi; Singh, Gaurav; Sharma, Lokendra K.; Pandey, Vibha; Kumari, Nishi; Misra, Pratibha

2013-01-01

Background Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress. Methodology The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress

Analysis of the Arabidopsis IRX9/IRX9-L and IRX14/IRX14-L pairs of glycosyltransferase genes reveals critical contributions to biosynthesis of the hemicellulose glucuronoxylan.

Science.gov (United States)

Wu, Ai-Min; Hörnblad, Emma; Voxeur, Aline; Gerber, Lorenz; Rihouey, Christophe; Lerouge, Patrice; Marchant, Alan

2010-06-01

The hemicellulose glucuronoxylan (GX) is a major component of plant secondary cell walls. However, our understanding of GX synthesis remains limited. Here, we identify and analyze two new genes from Arabidopsis (Arabidopsis thaliana), IRREGULAR XYLEM9-LIKE (IRX9-L) and IRX14-LIKE (IRX14-L) that encode glycosyltransferase family 43 members proposed to function during xylan backbone elongation. We place IRX9-L and IRX14-L in a genetic framework with six previously described glycosyltransferase genes (IRX9, IRX10, IRX10-L, IRX14, FRAGILE FIBER8 [FRA8], and FRA8 HOMOLOG [F8H]) and investigate their function in GX synthesis. Double-mutant analysis identifies IRX9-L and IRX14-L as functional homologs of IRX9 and IRX14, respectively. Characterization of irx9 irx10 irx14 fra8 and irx9-L irx10-L irx14-L f8h quadruple mutants allows definition of a set of genes comprising IRX9, IRX10, IRX14, and FRA8 that perform the main role in GX synthesis during vegetative development. The IRX9-L, IRX10-L, IRX14-L, and F8H genes are able to partially substitute for their respective homologs and normally perform a minor function. The irx14 irx14-L double mutant virtually lacks xylan, whereas irx9 irx9-L and fra8 f8h double mutants form lowered amounts of GX displaying a greatly reduced degree of backbone polymerization. Our findings reveal two distinct sets of four genes each differentially contributing to GX biosynthesis.

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean[W][OA

Science.gov (United States)

Sayama, Takashi; Ono, Eiichiro; Takagi, Kyoko; Takada, Yoshitake; Horikawa, Manabu; Nakamoto, Yumi; Hirose, Aya; Sasama, Hiroko; Ohashi, Mihoko; Hasegawa, Hisakazu; Terakawa, Teruhiko; Kikuchi, Akio; Kato, Shin; Tatsuzaki, Nana; Tsukamoto, Chigen; Ishimoto, Masao

2012-01-01

Triterpene saponins are a diverse group of biologically functional products in plants. Saponins usually are glycosylated, which gives rise to a wide diversity of structures and functions. In the group A saponins of soybean (Glycine max), differences in the terminal sugar species located on the C-22 sugar chain of an aglycone core, soyasapogenol A, were observed to be under genetic control. Further genetic analyses and mapping revealed that the structural diversity of glycosylation was determined by multiple alleles of a single locus, Sg-1, and led to identification of a UDP-sugar–dependent glycosyltransferase gene (Glyma07g38460). Although their sequences are highly similar and both glycosylate the nonacetylated saponin A0-αg, the Sg-1a allele encodes the xylosyltransferase UGT73F4, whereas Sg-1b encodes the glucosyltransferase UGT73F2. Homology models and site-directed mutagenesis analyses showed that Ser-138 in Sg-1a and Gly-138 in Sg-1b proteins are crucial residues for their respective sugar donor specificities. Transgenic complementation tests followed by recombinant enzyme assays in vitro demonstrated that sg-10 is a loss-of-function allele of Sg-1. Considering that the terminal sugar species in the group A saponins are responsible for the strong bitterness and astringent aftertastes of soybean seeds, our findings herein provide useful tools to improve commercial properties of soybean products. PMID:22611180

UGT74AN1, a Permissive Glycosyltransferase from Asclepias curassavica for the Regiospecific Steroid 3-O-Glycosylation.

Science.gov (United States)

Wen, Chao; Huang, Wei; Zhu, Xue-Lin; Li, Xiao-San; Zhang, Fan; Jiang, Ren-Wang

2018-02-02

A permissive steroid glycosyltransferase (UGT74AN1) from Asclepias curassavica exhibited robust capabilities for the regiospecific C3 glycosylation of cardiotonic steroids and C 21 steroid precursors, and unprecedented promiscuity toward 53 structurally diverse natural and unnatural compounds to form O-, N-, and S-glycosides, along with the catalytic reversibility for a one-pot transglycosylation reaction. These findings highlight UGT74AN1 as the first regiospecific catalyst for cardiotonic steroid C3 glycosylation and exhibit significant potential for glycosylation of diverse bioactive molecules in drug discovery.

Mutation induction by ion beams in higher plants

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2003-04-01

This review mainly describes study results obtained in the Takasaki ion-beam (IB) irradiation facility (TIARA) on the mutation induction in higher plants. Biological effects like lethality and on budding of IBs (carbon, Ne and Ar) are discussed in relation with their linear energy transfer (LET), relative biological effectiveness and the developmental states in shepherd's-purse and tobacco. Induced mutation by IB are characterized by those findings that the mutation rate by C beam is 1.9 x 10{sup -6}, being 17 times higher than the electron beam, in the shepherd's-purse, that C beam induces larger structural changes than electron beam when examined by molecular mechanism of tt and gl gene mutations, and that mutation spectrum of IB is different from that of {gamma}-ray and is wider. Novel mutants are described on shepherd's-purse (pigment mutants, ultraviolet (UV)-resistant and sensitive ones, and flowering ones), disease-resistant rice, barley and tobacco plants, and flowering plants. IB mutation is possibly useful for solving the problems of environment and foods in future. (N.I.)

Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment

Directory of Open Access Journals (Sweden)

Silje A. Wolff

2014-05-01

Full Text Available Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA has developed the Micro-Ecological Life Support System Alternative (MELiSSA program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space.

Heterologous expression of plant cell wall glycosyltransferases in Pichia, pea and tobacco

DEFF Research Database (Denmark)

Petersen, Bent Larsen; Damager, Iben; Faber, Kirsten

Cell). In the present study, Flag-tagged (MDYKDDDD) RGXT2 was expressed in Pichia pastoris as secreted soluble protein, in pea (using the Pea early browning virus as expression vector) as soluble intra-cellular protein and in tobacco as full length membrane bound protein. The amount of expressed...... to participate in plant CW biosynthesis, has been achieved in only a few cases. We have previously reported the characterisation of two highly homologous plant-specific membrane-bound GTs, which when expressed as secreted tagged soluble proteins in the baculo virus system, catalysed the transfer of xylose from...... protein was estimated using anti Flag Ab and corresponding activity monitored. Pros and cons of using the various expression systems are discussed....

The ways of controlling microbiota of the higher plant link in LSS

Science.gov (United States)

Tirranen, L. S.; Gitelson, I. I.

The ways of controlling microbiota of the higher plant link have been considered, as the sterile plant growth in closed ecological human life support systems is impossible. One of the ways of controlling the link microbial community - building sterile intrasystem barriers between the system links - is problematic and dangerous. An accidental breach of microorganisms through the barrier can lead to disastrous consequences - either unrestrained reproduction of microbes including pathogenic and conditionally pathogenic species or, on the contrary, elimination of species most valuable for the given microbial community. Another way of control is maintaining suitable conditions for human and plant habitat, creating some constructive system properties directed at microbial exchange weakening. The use of catalytic furnace for oxidizing organic impurities in system atmosphere, UV processing of air and plants in the phytotron before and in the beginning of the experiments promoted decrease of microorganism amount in the link. To restrict the distribution of microorganisms of the higher plant link in other system links the module for yield processing being under constant suction was isolated. To prevent the introduction of microorganisms into the system we applied the UV processing of all objects transferred to the system and continuous atmosphere overpressure inside the system. It is important to detect the ultimate amount of microorganism indicator groups in the higher plant link biocenosis. It would indicate the microbial pollution of the link and be the signal for regulation of its microbial population or processing technologies in the studied objects. There were two 4-month experiments with the "human - higher plants" closed ecosystem carried out. There was no progressive deterioration for plants, decrease of wheat yield to zero and rapid growth of microorganisms in the higher plant link after making all listed arrangements. Microbiological analyses of the studied

Consideration of higher seismic loads at existing plants

Energy Technology Data Exchange (ETDEWEB)

Liebig, J.; Pellissetti, M.

2015-07-01

Because of advancement of methods in probabilistic seismic hazard analysis, plenty of existing plants face higher seismic loads as an obligation from the national authorities. In case of such obligations safety related structures and equipment have to be reevaluated or requalified for the increased seismic loads. The paper provides solutions for different kinds of structures and equipment inside the plant, avoiding cost intensive hardware exchange. Due to higher seismic loads different kinds of structures and equipment inside a plant have to be reevaluated. For civil structures, primary components, mechanical components, distribution lines and electrical and I&C equipment different innovative concepts will be applied to keep structures and equipment qualified for the higher seismic loads. Detailed analysis, including the modeling of non-linear phenomena, or minor structural upgrades are cost competitive, compared to cost intensive hardware exchanges. Several case studies regarding the re-evaluation and requalification of structures and equipment due to higher seismic loads are presented. It is shown how the creation of coupled finite element models and the consistent propagation of acceleration time histories through the soil, building and primary circuit lead to a significant load reduction Electrical and I&C equipment is reinforced by smart upgrades which increase the natural equipment frequencies. Therefore for all devices inside the cabinets the local acceleration will not increase and the seismic qualification will be maintained. The case studies cover both classical deterministic and probabilistic re-evaluations (fragility analysis). Furthermore, the substantial benefits of non-linear limit load evaluation, such as push-over analysis of buildings and limit load analysis of fuel assemblies, are demonstrated. (Author)

Overexpression of Brucella putative glycosyltransferase WbkA in B. abortus RB51 leads to production of exopolysaccharide.

Science.gov (United States)

Dabral, Neha; Jain-Gupta, Neeta; Seleem, Mohamed N; Sriranganathan, Nammalwar; Vemulapalli, Ramesh

2015-01-01

Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis in mammals. Brucella strains containing the O-polysaccharide in their cell wall structure exhibit a smooth phenotype whereas the strains devoid of the polysaccharide show rough phenotype. B. abortus strain RB51 is a stable rough attenuated mutant which is used as a licensed live vaccine for bovine brucellosis. Previous studies have shown that the wboA gene, which encodes a glycosyltransferase required for the synthesis of O-polysaccharide, is disrupted in B. abortus RB51 by an IS711 element. Although complementation of strain RB51 with a functional wboA gene results in O-polysaccharide synthesis in the cytoplasm, it does not result in smooth phenotype. The aim of this study was to determine if overexpression of Brucella WbkA or WbkE, two additional putative glycosyltransferases essential for O-polysaccharide synthesis, in strain RB51 would result in the O-polysaccharide synthesis and smooth phenotype. Our results demonstrate that overexpression of wbkA or wbkE gene in RB51 does not result in O-polysaccharide expression as shown by Western blotting with specific antibodies. However, wbkA, but not wbkE, overexpression leads to the development of a clumping phenotype and the production of exopolysaccharide(s) containing mannose, galactose, N-acetylglucosamine, and N-acetylgalactosamine. Moreover, we found that the clumping recombinant strain displays increased adhesion to polystyrene plates. The recombinant strain was similar to strain RB51 in its attenuation characteristic and in its ability to induce protective immunity against virulent B. abortus challenge in mice.

Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

Science.gov (United States)

Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

2015-04-01

The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

Directory of Open Access Journals (Sweden)

Tomáš Trnka

2015-04-01

Full Text Available The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi. The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

Novel Occurrence of Uncommon Polyamines in Higher Plants 1

Science.gov (United States)

Kuehn, Glenn D.; Rodriguez-Garay, Benjamin; Bagga, Suman; Phillips, Gregory C.

1990-01-01

Diamines and polyamines are ubiquitous components of living cells, and apparently are involved in numerous cellular and physiological processes. Certain “uncommon” polyamines have limited distribution in nature and have been associated primarily with organisms adapted to extreme environments, although the precise function of these polyamines in such organisms is unknown. This article summarizes current knowledge regarding the occurrence in higher plants of the uncommon polyamines related to and including norspermidine and norspermine. A putative biosynthetic pathway to account for the occurrences of these uncommon polyamines in higher plants is presented, with a summary of the supporting evidence indicating the existence of the requisite enzymatic activities in alfalfa, Medicago sativa L. PMID:16667862

Functional architecture of higher plant photosystem II supercomplexes

NARCIS (Netherlands)

Caffarri, Stefano; Kouril, Roman; Kereiche, Sami; Boekema, Egbert J.; Croce, Roberta; Kereïche, Sami

2009-01-01

Photosystem II ( PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it

Uptake and distribution of mercury within higher plants

Energy Technology Data Exchange (ETDEWEB)

Beauford, W; Barber, J; Barringer, A R

1977-04-15

The uptake and distribution of inorganic mercury (HgCl/sub 2/) within higher plants (Pisum sativum and Mentha spicata) was examined using solution culture and radiotracer techniques. Plants were found to tolerate an external level of 1 mgHg/kg of solution but both physiological and biochemical processes were affected at 5 mgHg/kg and 10 mgHg/kg. The uptake of Hg into plants grown in hydroponic solution was a function of external concentration. Over the concentration range considered the accumulation of Hg in the roots was linear on a log-log basis although the uptake of the element into the shoots appeared to be two-phased. The distribution of Hg in plants was asymmetrical with much greater amounts of the element in the roots than the shoots. Although the level of Hg increased generally in plant tissues with increasing external levels, the proportion retained in the roots, relative to the shoots, was constant (approximately 95%). Two binding characteristics of the Hg within plant tissue were detected. A major proportion of Hg was tightly bound, being unaffected by treatment with ethanol and hydrochloric acid. The remaining Hg in the tissue was removed by either water or hydrochloric acid treatment. Cell fractionation indicated that the major binding component of Hg in plant tissues was the cell wall.

Overexpression of Brucella putative glycosyltransferase WbkA in B. abortus RB51 leads to production of exopolysaccharide

Directory of Open Access Journals (Sweden)

Neha eDabral

2015-06-01

Full Text Available Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis in mammals. Brucella strains containing the O-polysaccharide in their cell wall structure exhibit a smooth phenotype whereas the strains devoid of the polysaccharide show rough phenotype. B. abortus strain RB51 is a stable rough attenuated mutant which is used as a licensed live vaccine for bovine brucellosis. Previous studies have shown that the wboA gene, which encodes a glycosyltransferase required for the synthesis of O-polysaccharide, is disrupted in B. abortus RB51 by an IS711 element. Although complementation of strain RB51 with a functional wboA gene results in O-polysaccharide synthesis in the cytoplasm, it does not result in smooth phenotype. The aim of this study was to determine if overexpression of Brucella WbkA or WbkE, two additional putative glycosyltransferases essential for O-polysaccharide synthesis, in strain RB51 would result in the O-polysaccharide synthesis and smooth phenotype. Our results demonstrate that overexpression of wbkA or wbkE gene in RB51 does not result in O-polysaccharide expression as shown by Western blotting with specific antibodies. However, wbkA, but not wbkE, overexpression leads to the development of a clumping phenotype and the production of exopolysaccharide(s containing mannose, galactose, N-acetylglucosamine and N-acetylgalactosamine. Moreover, we found that the clumping recombinant strain displays increased adhesion to polystyrene plates. The recombinant strain was similar to strain RB51 in its attenuation characteristic and in its ability to induce protective immunity against virulent B. abortus challenge in mice.

Higher plant vegetation changes during Pliocene sapropel formation

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Menzel, D.; Schouten, S.; Bergen, P.F. van

2004-01-01

The 13C values of higher plant wax C27 33 n-alkanes were determined in three, time-equivalent Pliocene (2.943 Ma) sapropels and homogeneous calcareous ooze from three different sites forming an east-west transect in the eastern Mediterranean Basin in order to study the composition of the vegetation

Computational identification of candidate nucleotide cyclases in higher plants

KAUST Repository

Wong, Aloysius Tze; Gehring, Christoph A

2013-01-01

In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs

UDP-Glycosyltransferases from the UGT73C Subfamily in Barbarea vulgaris Catalyze Sapogenin 3-O-Glucosylation in Saponin-Mediated Insect Resistance1[W][OA

Science.gov (United States)

Augustin, Jörg M.; Drok, Sylvia; Shinoda, Tetsuro; Sanmiya, Kazutsuka; Nielsen, Jens Kvist; Khakimov, Bekzod; Olsen, Carl Erik; Hansen, Esben Halkjær; Kuzina, Vera; Ekstrøm, Claus Thorn; Hauser, Thure; Bak, Søren

2012-01-01

Triterpenoid saponins are bioactive metabolites that have evolved recurrently in plants, presumably for defense. Their biosynthesis is poorly understood, as is the relationship between bioactivity and structure. Barbarea vulgaris is the only crucifer known to produce saponins. Hederagenin and oleanolic acid cellobioside make some B. vulgaris plants resistant to important insect pests, while other, susceptible plants produce different saponins. Resistance could be caused by glucosylation of the sapogenins. We identified four family 1 glycosyltransferases (UGTs) that catalyze 3-O-glucosylation of the sapogenins oleanolic acid and hederagenin. Among these, UGT73C10 and UGT73C11 show highest activity, substrate specificity and regiospecificity, and are under positive selection, while UGT73C12 and UGT73C13 show lower substrate specificity and regiospecificity and are under purifying selection. The expression of UGT73C10 and UGT73C11 in different B. vulgaris organs correlates with saponin abundance. Monoglucosylated hederagenin and oleanolic acid were produced in vitro and tested for effects on P. nemorum. 3-O-β-d-Glc hederagenin strongly deterred feeding, while 3-O-β-d-Glc oleanolic acid only had a minor effect, showing that hydroxylation of C23 is important for resistance to this herbivore. The closest homolog in Arabidopsis thaliana, UGT73C5, only showed weak activity toward sapogenins. This indicates that UGT73C10 and UGT73C11 have neofunctionalized to specifically glucosylate sapogenins at the C3 position and demonstrates that C3 monoglucosylation activates resistance. As the UGTs from both the resistant and susceptible types of B. vulgaris glucosylate sapogenins and are not located in the known quantitative trait loci for resistance, the difference between the susceptible and resistant plant types is determined at an earlier stage in saponin biosynthesis. PMID:23027665

Crystal Structure of a UDP-glucose-specific Glycosyltransferase from a Mycobacterium Species

Energy Technology Data Exchange (ETDEWEB)

Fulton, Zara; McAlister, Adrian; Wilce, Matthew C.J.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Perugini, Matthew A.; Bottomley, Stephen P.; Coppel, Ross L.; Crellin, Paul K.; Rossjohn, Jamie; Beddoe, Travis (Monash); (Melbourne)

2008-10-24

Glycosyltransferases (GTs) are a large and ubiquitous family of enzymes that specifically transfer sugar moieties to a range of substrates. Mycobacterium tuberculosis contains a large number of GTs, many of which are implicated in cell wall synthesis, yet the majority of these GTs remain poorly characterized. Here, we report the high resolution crystal structures of an essential GT (MAP2569c) from Mycobacterium avium subsp. paratuberculosis (a close homologue of Rv1208 from M. tuberculosis) in its apo- and ligand-bound forms. The structure adopted the GT-A fold and possessed the characteristic DXD motif that coordinated an Mn{sup 2+} ion. Atypical of most GTs characterized to date, MAP2569c exhibited specificity toward the donor substrate, UDP-glucose. The structure of this ligated complex revealed an induced fit binding mechanism and provided a basis for this unique specificity. Collectively, the structural features suggested that MAP2569c may adopt a 'retaining' enzymatic mechanism, which has implications for the classification of other GTs in this large superfamily.

Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

Science.gov (United States)

Hacham, Yael; Matityahu, Ifat; Amir, Rachel

2017-07-01

Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

Rare ginsenoside Ia synthesized from F1 by cloning and overexpression of the UDP-glycosyltransferase gene from Bacillus subtilis: synthesis, characterization, and in vitro melanogenesis inhibition activity in BL6B16 cells.

Science.gov (United States)

Wang, Dan-Dan; Jin, Yan; Wang, Chao; Kim, Yeon-Ju; Perez, Zuly Elizabeth Jimenez; Baek, Nam In; Mathiyalagan, Ramya; Markus, Josua; Yang, Deok-Chun

2018-01-01

Ginsenoside F1 has been described to possess skin-whitening effects on humans. We aimed to synthesize a new ginsenoside derivative from F1 and investigate its cytotoxicity and melanogenesis inhibitory activity in B16BL6 cells using recombinant glycosyltransferase enzyme. Glycosylation has the advantage of synthesizing rare chemical compounds from common compounds with great ease. UDP-glycosyltransferase (BSGT1) gene from Bacillus subtilis was selected for cloning. The recombinant glycosyltransferase enzyme was purified, characterized, and utilized to enzymatically transform F1 into its derivative. The new product was characterized by NMR techniques and evaluated by MTT, melanin count, and tyrosinase inhibition assay. The new derivative was identified as (20 S )-3 β ,6 α ,12 β ,20-tetrahydroxydammar-24-ene-20- O - β -D-glucopyranosyl-3- O - β -D-glucopyranoside (ginsenoside Ia), which possesses an additional glucose linked into the C-3 position of substrate F1. Ia had been previously reported; however, no in vitro biological activity was further examined. This study focused on the mass production of arduous ginsenoside Ia from accessible F1 and its inhibitory effect of melanogenesis in B16BL6 cells. Ia showed greater inhibition of melanin and tyrosinase at 100 μmol/L than F1 and arbutin. These results suggested that Ia decreased cellular melanin synthesis in B16BL6 cells through downregulation of tyrosinase activity. To our knowledge, this is the first study to report on the mass production of rare ginsenoside Ia from F1 using recombinant UDP-glycosyltransferase isolated from B. subtillis and its superior melanogenesis inhibitory activity in B16BL6 cells as compared to its precursor. In brief, ginsenoside Ia can be applied for further study in cosmetics.

Aquatic food production modules in bioregenerative life support systems based on higher plants

Science.gov (United States)

Bluem, V.; Paris, F.

Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity.

Diurnal adjustment in ultraviolet sunscreen protection is widespread among higher plants.

Science.gov (United States)

Barnes, Paul W; Flint, Stephan D; Tobler, Mark A; Ryel, Ronald J

2016-05-01

The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) in the epidermis of higher plants reduces the penetration of solar UV radiation to underlying tissues and is a primary mechanism of acclimation to changing UV conditions resulting from ozone depletion and climate change. Previously we reported that several herbaceous plant species were capable of rapid, diurnal adjustments in epidermal UV transmittance (T UV), but how widespread this phenomenon is among plants has been unknown. In the present study, we tested the generality of this response by screening 37 species of various cultivated and wild plants growing in four locations spanning a gradient of ambient solar UV and climate (Hawaii, Utah, Idaho and Louisiana). Non-destructive measurements of adaxial T UV indicated that statistically significant midday decreases in T UV occurred in 49 % of the species tested, including both herbaceous and woody growth forms, and there was substantial interspecific variation in the magnitude of these changes. In general, plants in Louisiana exhibited larger diurnal changes in T UV than those in the other locations. Moreover, across all taxa, the magnitude of these changes was positively correlated with minimum daily air temperatures but not daily UV irradiances. Results indicate that diurnal changes in UV shielding are widespread among higher plants, vary both within and among species and tend to be greatest in herbaceous plants growing in warm environments. These findings suggest that plant species differ in their UV protection "strategies" though the functional and ecological significance of this variation in UV sunscreen protection remains unclear at present.

Glycemic Response to Corn Starch Modified with Cyclodextrin Glycosyltransferase and its Relationship to Physical Properties.

Science.gov (United States)

Dura, A; Yokoyama, W; Rosell, C M

2016-09-01

Corn starch was modified with cyclodextrin glycosyltransferase (CGTase) below the gelatinization temperature. The porous granules with or without CGTase hydrolysis products may be used as an alternative to modified corn starches in foods applications. The amount and type of hydrolysis products were determined, containing mainly β-cyclodextrin (CD), which will influence pasting behavior and glycemic response in mice. Irregular surface and small holes were observed by microscopic analysis and differences in pasting properties were observed in the presence of hydrolysis products. Postprandial blood glucose in mice fed gelatinized enzymatically modified starch peaked earlier than their ungelatinized counterparts. However, in ungelatinized enzymatically modified starches, the presence of β- CD may inhibit the orientation of amylases slowing hydrolysis, which may help to maintain lower blood glucose levels. Significant correlations were found between glycemic curves and viscosity pattern of starches.

Molecular Evolution of the Glycosyltransferase 6 Gene Family in Primates

Directory of Open Access Journals (Sweden)

Eliane Evanovich

2016-01-01

Full Text Available Glycosyltransferase 6 gene family includes ABO, Ggta1, iGb3S, and GBGT1 genes and by three putative genes restricted to mammals, GT6m6, GTm6, and GT6m7, only the latter is found in primates. GT6 genes may encode functional and nonfunctional proteins. Ggta1 and GBGT1 genes, for instance, are pseudogenes in catarrhine primates, while iGb3S gene is only inactive in human, bonobo, and chimpanzee. Even inactivated, these genes tend to be conversed in primates. As some of the GT6 genes are related to the susceptibility or resistance to parasites, we investigated (i the selective pressure on the GT6 paralogs genes in primates; (ii the basis of the conservation of iGb3S in human, chimpanzee, and bonobo; and (iii the functional potential of the GBGT1 and GT6m7 in catarrhines. We observed that the purifying selection is prevalent and these genes have a low diversity, though ABO and Ggta1 genes have some sites under positive selection. GT6m7, a putative gene associated with aggressive periodontitis, may have regulatory function, but experimental studies are needed to assess its function. The evolutionary conservation of iGb3S in humans, chimpanzee, and bonobo seems to be the result of proximity to genes with important biological functions.

Probing the Catalytic Promiscuity of a Regio- and Stereospecific C-Glycosyltransferase from Mangifera indica.

Science.gov (United States)

Chen, Dawei; Chen, Ridao; Wang, Ruishan; Li, Jianhua; Xie, Kebo; Bian, Chuancai; Sun, Lili; Zhang, Xiaolin; Liu, Jimei; Yang, Lin; Ye, Fei; Yu, Xiaoming; Dai, Jungui

2015-10-19

The catalytic promiscuity of the novel benzophenone C-glycosyltransferase, MiCGT, which is involved in the biosynthesis of mangiferin from Mangifera indica, was explored. MiCGT exhibited a robust capability to regio- and stereospecific C-glycosylation of 35 structurally diverse druglike scaffolds and simple phenolics with UDP-glucose, and also formed O- and N-glycosides. Moreover, MiCGT was able to generate C-xylosides with UDP-xylose. The OGT-reversibility of MiCGT was also exploited to generate C-glucosides with simple sugar donor. Three aryl-C-glycosides exhibited potent SGLT2 inhibitory activities with IC50  values of 2.6×, 7.6×, and 7.6×10(-7)  M, respectively. These findings demonstrate for the first time the significant potential of an enzymatic approach to diversification through C-glycosidation of bioactive natural and unnatural products in drug discovery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bioinformatics analysis of the predicted polyprenol reductase genes in higher plants

Science.gov (United States)

Basyuni, M.; Wati, R.

2018-03-01

The present study evaluates the bioinformatics methods to analyze twenty-four predicted polyprenol reductase genes from higher plants on GenBank as well as predicted the structure, composition, similarity, subcellular localization, and phylogenetic. The physicochemical properties of plant polyprenol showed diversity among the observed genes. The percentage of the secondary structure of plant polyprenol genes followed the ratio order of α helix > random coil > extended chain structure. The values of chloroplast but not signal peptide were too low, indicated that few chloroplast transit peptide in plant polyprenol reductase genes. The possibility of the potential transit peptide showed variation among the plant polyprenol reductase, suggested the importance of understanding the variety of peptide components of plant polyprenol genes. To clarify this finding, a phylogenetic tree was drawn. The phylogenetic tree shows several branches in the tree, suggested that plant polyprenol reductase genes grouped into divergent clusters in the tree.

Arabidopsis thaliana RGXT1 and RGXT2 encode Golgi-localized (1,3)-alpha-D-xylosyltransferases involved in the synthesis of pectic rhamnogalacturonan-II

DEFF Research Database (Denmark)

Madsen, Jack Egelund; Petersen, Bent Larsen; Motawia, Mohammed Saddik

2006-01-01

in rhamnogalacturonan-II, a complex polysaccharide essential to vascular plants, and is conserved across higher plant families. Rhamnogalacturonan-II isolated from both RGXT1 and RGXT2 T-DNA insertional mutants functioned as specific acceptor molecules in the xylosyltransferase assay. Expression of RGXT1- and RGXT2......Two homologous plant-specific Arabidopsis thaliana genes, RGXT1 and RGXT2, belong to a new family of glycosyltransferases (CAZy GT-family-77) and encode cell wall (1,3)-alpha-d-xylosyltransferases. The deduced amino acid sequences contain single transmembrane domains near the N terminus, indicative...

Enzymatic Synthesis of Acylphloroglucinol 3-C-Glucosides from 2-O-Glucosides using a C-Glycosyltransferase from Mangifera indica.

Science.gov (United States)

Chen, Dawei; Sun, Lili; Chen, Ridao; Xie, Kebo; Yang, Lin; Dai, Jungui

2016-04-18

A green and cost-effective process for the convenient synthesis of acylphloroglucinol 3-C-glucosides from 2-O-glucosides was exploited using a novel C-glycosyltransferase (MiCGTb) from Mangifera indica. Compared with previously characterized CGTs, MiCGTb exhibited unique de-O-glucosylation promiscuity and high regioselectivity toward structurally diverse 2-O-glucosides of acylphloroglucinol and achieved high yields of C-glucosides even with a catalytic amount of uridine 5'-diphosphate (UDP). These findings demonstrate for the first time the significant potential of a single-enzyme approach to the synthesis of bioactive C-glucosides from both natural and unnatural acylphloroglucinol 2-O-glucosides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptidoglycan glycosyltransferase substrate mimics as templates for the design of new antibacterial drugs

Directory of Open Access Journals (Sweden)

Adeline eDerouaux

2013-03-01

Full Text Available Peptidoglycan (PG is an essential net-like macromolecule that surrounds bacteria, gives them their shape, and protects them against their own high osmotic pressure. PG synthesis inhibition leads to bacterial cell lysis, making it an important target for many antibiotics. The final two reactions in PG synthesis are performed by penicillin-binding proteins (PBPs. Their glycosyltransferase (GT activity uses the lipid II precursor to synthesize glycan chains and their transpeptidase (TP activity catalyzes the cross-linking of two glycan chains via the peptide side chains. Inhibition of either of these two reactions leads to bacterial cell death. β-Lactam antibiotics target the transpeptidation reaction while antibiotic therapy based on inhibition of the GTs remains to be developed. Ongoing research is trying to fill this gap by studying the interactions of GTs with inhibitors and substrate mimics and utilizing the latter as templates for the design of new antibiotics. In this mini review we present an updated overview on the GTs and describe the structure-activity relationship of recently developed synthetic ligands.

Predicting molybdenum toxicity to higher plants: Influence of soil properties

International Nuclear Information System (INIS)

McGrath, S.P.; Mico, C.; Curdy, R.; Zhao, F.J.

2010-01-01

The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED 50 ) of Mo in different soils, explaining > 65% of the variance in ED 50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

Inositol trisphosphate receptor in higher plants: is it real?

Czech Academy of Sciences Publication Activity Database

Krinke, Ondřej; Novotná, Z.; Valentová, O.; Martinec, Jan

2007-01-01

Roč. 58, č. 3 (2007), s. 361-376 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LC06034 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : Ca2+ signalling * higher plants * inositol trisphosphate receptor Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

Functional architecture of higher plant photosystem II supercomplexes

OpenAIRE

Caffarri, Stefano; Kouřil, Roman; Kereïche, Sami; Boekema, Egbert J; Croce, Roberta

2009-01-01

Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C2S2M2 supercomplex were isolated. Ch...

Predicting molybdenum toxicity to higher plants: Influence of soil properties

Energy Technology Data Exchange (ETDEWEB)

McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

2010-10-15

The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

Research on mutation generation in higher plants with heavy ions at NIRS-HIMAC

International Nuclear Information System (INIS)

Okamura, M.; Watanabe, S.; Watanabe, M.; Toguri, T.; Furusawa, Y.

2006-01-01

Plants are closely related to medical treatment in medicine, foods, herbs and medical care by gardening. Ion beams have much higher linear energy transfer (LET) and relative biological effectiveness than those of gamma rays and X-rays. Ion beams are supposed to be useful as new mutagen to obtain novel mutants with superior characteristics in higher plants. In this study, the influence of heavy ions irradiation on bud growth was examined in carnation and the mutation generation was inspected in babies' breath. The growth of carnation buds began to decrease at 10 Gy and the median growth dose was estimated at 35 Gy for 290 Mev/u carbon ion beams. Mutants with petaloid leaves were observed in babies' breath by the irradiation of 290 Mev/u carbon ion beams at 20Gy. We will examine the mutation rates and spectrum for 290 MeV/u carbon, 400 MeV/u neon and 500 MeV/u argon ion beams to find optimum use of the beams in plant breeding. The efficient system to generate useful mutants using heavy ions at NIRS-HIMAC will be developed in higher plants. (author)

Impact of common cytostatic drugs on pollen fertility in higher plants.

Science.gov (United States)

Mišík, Miroslav; Kundi, Michael; Pichler, Clemens; Filipic, Metka; Rainer, Bernhard; Mišíková, Katarina; Nersesyan, Armen; Knasmueller, Siegfried

2016-08-01

Cytostatic drugs are among the most toxic chemicals which are produced. Many of them cause damage of the genetic material which may affect the fertility of higher organisms. To study the impact of the widely used anticancer drugs [cisplatin (CisPt), etoposide (Et), and 5-fluorouracil (5-FU)] on the reproduction of higher plants, pollen abortion experiments were conducted with species which belong to major plant families, namely with Tradescantia paludosa (Commelinaceae), Arabidopsis thaliana (Brassicaceae), Chelidonium majus (Papaveraceae), and Alisma plantago-aquatica (Alismataceae). All compounds increased the frequencies of abortive grains. The lowest effective doses were in general in a narrow range (i.e., 1 and 10 mg/kg of dry soil). The effects of the individual drugs were similar in T. paludosa, A. plantago-aquatica, and Ch. majus, while A. thaliana was consistently less sensitive. The highest abortion rate was obtained in most experiments with CisPt, followed by 5-FU and Et. Comparisons of the doses which caused effects in the present experiments in the different species with the predicted environment concentrations and with the levels of the cytostatics which were detected in hospital wastewaters show that the realistic environmental concentrations of the drugs are 4-6 orders of magnitude lower. Therefore, it is unlikely that these drugs affect the fertility of higher plants in aquatic and terrestrial ecosystems.

Cytoplasniic differentiation during microsporogenesis in higher plants

Directory of Open Access Journals (Sweden)

H. Dichinnson

2014-01-01

Full Text Available Conspicuous cytoplasmic dedifferentiation in the pollen mother cells takes place early in the meiotic prophase of many plants. This event involves the removal of much of the cytoplasmic RNA. and the differentiation of both plastids and mitochondria to approaching the sole expression of their genomes. Much of the RNA removed from the cytoplasm passes to the nucleoplasm where it is utilised in the construction of a new `generation' of ribusomes. These new ribosomes are incorporated into cytoplasmic `nuclewhich disintegrate in the post-meiotic cytoplasm, restoring its ribosomes to pre-prophase levels. These changes are interpreted as evidence of a process by which the cytoplasm is cleansed of sporophytic control elements, both for the expression of the new gametophytic genome, and in the female cells of higher plants, for transmission to the new generation. The absence of control elements (presumably long-term messenger RNA from the cytoplasm would result in the dedifferentiation observed in the organelles, and the low levels of reserves in these cells presumably results in characteristically lengthy and unusual redifferentiation of both plastids and mitochondria, once information-carrying molecules again enter the cytosol.

Use of higher plants as screens for toxicity assessment.

Science.gov (United States)

Kristen, U

1997-01-01

This review deals with the use of entire plants, seedlings, cell suspension cultures and pollen tubes for the estimation of potential toxicity in the environment, and for risk assessment of chemicals and formulations of human relevance. It is shown that the roots of onions and various crop seedlings, as well as in vitro growing pollen tubes of some mono- and dicotyledonous plants, are most frequently used to obtain toxicity data by determination of root and tube growth inhibition. Both roots and pollen tubes are chloroplast free, non-photosynthetic systems and, therefore, with regard to their cytotoxic reactions are closer to vertebrate tissues and cells than are chloroplast-containing plant organs. Root tips and anthers of flower buds are shown to be applicable to genotoxicity screening by microscopic analysis of mitotic or meiotic aberrations during cell division or microspore development, respectively. The processes of mitosis and meiosis are similar in plants and animals. Therefore, meristematic and sporogenic tissues of plants generally show patterns of cytotoxic response similar to those of embryogenic and spermatogenic tissues of vertebrates. The suitability of root tips, cell suspensions and pollen tubes for the investigation of mechanisms of toxic action and for the analysis of structure-activity relationships is also demonstrated. Two plant-based assays, the Allium test and the pollen tube growth test, both currently being evaluated alongside with established mammalian in vivo and in vitro protocols, are emphasized with regard to their potential use as alternatives to animal in vivo toxicity tests. For both assays, preliminary results indicate that the tips of growing roots and the rapidly elongating pollen tubes of certain higher plant species are as reliable as mammalian cell lines for detecting basal cytotoxicity. It is suggested that seeds and pollen grains, in particular, provide easily storable and convenient systems for inexpensive, relatively

A tandem array of UDP-glycosyltransferases from the UGT73C subfamily glycosylate sapogenins, forming a spectrum of mono- and bisdesmosidic saponins.

Science.gov (United States)

Erthmann, Pernille Østerbye; Agerbirk, Niels; Bak, Søren

2018-05-01

This study identifies six UGT73Cs all able to glucosylate sapogenins at positions 3 and/or 28 which demonstrates that B. vulgaris has a much richer arsenal of UGTs involved in saponin biosynthesis than initially anticipated. The wild cruciferous plant Barbarea vulgaris is resistant to some insects due to accumulation of two monodesmosidic triterpenoid saponins, oleanolic acid 3-O-β-cellobioside and hederagenin 3-O-β-cellobioside. Insect resistance depends on the structure of the sapogenin aglycone and the glycosylation pattern. The B. vulgaris saponin profile is complex with at least 49 saponin-like metabolites, derived from eight sapogenins and including up to five monosaccharide units. Two B. vulgaris UDP-glycosyltransferases, UGT73C11 and UGT73C13, O-glucosylate sapogenins at positions 3 and 28, forming mainly 3-O-β-D-glucosides. The aim of this study was to identify UGTs responsible for the diverse saponin oligoglycoside moieties observed in B. vulgaris. Twenty UGT genes from the insect resistant genotype were selected and heterologously expressed in Nicotiana benthamiana and/or Escherichia coli. The extracts were screened for their ability to glycosylate sapogenins (oleanolic acid, hederagenin), the hormone 24-epibrassinolide and sapogenin monoglucosides (hederagenin and oleanolic acid 3-O-β-D-glucosides). Six UGTs from the UGT73C subfamily were able to glucosylate both sapogenins and both monoglucosides at positions 3 and/or 28. Some UGTs formed bisdesmosidic saponins efficiently. At least four UGT73C genes were localized in a tandem array with UGT73C11 and possibly UGT73C13. This organization most likely reflects duplication events followed by sub- and neofunctionalization. Indeed, signs of positive selection on several amino acid sites were identified and modelled to be localized on the UGT protein surface. This tandem array is proposed to initiate higher order bisdesmosidic glycosylation of B. vulgaris saponins, leading to the recently discovered

Formation of higher plant component microbial community in closed ecological system

Science.gov (United States)

Tirranen, L. S.

2001-07-01

Closed ecological systems (CES) place at the disposal of a researcher unique possibilities to study the role of microbial communities in individual components and of the entire system. The microbial community of the higher plant component has been found to form depending on specific conditions of the closed ecosystem: length of time the solution is reused, introduction of intrasystem waste water into the nutrient medium, effect of other component of the system, and system closure in terms of gas exchange. The higher plant component formed its own microbial complex different from that formed prior to closure. The microbial complex of vegetable polyculture is more diverse and stable than the monoculture of wheat. The composition of the components' microflora changed, species diversity decreased, individual species of bacteria and fungi whose numbers were not so great before the closure prevailed. Special attention should be paid to phytopathogenic and conditionally pathogenic species of microorganisms potentially hazardous to man or plants and the least controlled in CES. This situation can endanger creation of CES and make conjectural existence of preplanned components, man, specifically, and consequently, of CES as it is.

Phototolerance of lichens, mosses and higher plants in an alpine environment: analysis of photoreactions.

Science.gov (United States)

Heber, U; Bilger, W; Bligny, R; Lange, O L

2000-11-01

Adaptation to excessive light is one of the requirements of survival in an alpine environment particularly for poikilohydric organisms which in contrast to the leaves of higher plants tolerate full dehydration. Changes in modulated chlorophyll fluorescence and 820-nm absorption were investigated in the lichens Xanthoria elegans (Link) Th. Fr. and Rhizocarpon geographicum (L.) DC, in the moss Grimmia alpestris Limpr. and the higher plants Geum montanum L., Gentiana lutea L. and Pisum sativum L., all collected at altitudes higher than 2000 m above sea level. In the dehydrated state, chlorophyll fluorescence was very low in the lichens and the moss, but high in the higher plants. It increased on rehydration in the lichens and the moss, but decreased in the higher plants. Light-induced charge separation in photosystem II was indicated by pulse-induced fluorescence increases only in dried leaves, not in the dry moss and dry lichens. Strong illumination caused photodamage in the dried leaves, but not in the dry moss and dry lichens. Light-dependent increases in 820-nm absorption revealed formation of potential quenchers of chlorophyll fluorescence in all dehydrated plants, but energy transfer to quenchers decreased chlorophyll fluorescence only in the moss and the lichens, not in the higher plants. In hydrated systems, coupled cyclic electron transport is suggested to occur concurrently with linear electron transport under strong actinic illumination particularly in the lichens because far more electrons became available after actinic illumination for the reduction of photo-oxidized P700 than were available in the pool of electron carriers between photosystems II and I. In the moss Grimmia, but not in the lichens or in leaves, light-dependent quenching of chlorophyll fluorescence was extensive even under nitrogen, indicating anaerobic thylakoid acidification by persistent cyclic electron transport. In the absence of actinic illumination, acidification by ca. 8% CO2 in

Importance of molybdenum in the nitrogen metabolism of microorganisms and higher plants

Energy Technology Data Exchange (ETDEWEB)

Mulder, E G

1948-01-01

The effect of molybdenum on the growth of microorganisms and higher plants and on some well-defined biochemical reactions was investigated. Results indicate that Aspergillus niger requires small amounts of molybdenum when growing in a culture solution supplied with nitrate nitrogen. With ammonium sulfate as a source of nitrogen, the response of the fungus to molybdenum was much smaller. It was shown that this different response of Aspergillus to molybdenum was not brought about by a difference in purity of both nitrogen compounds used, nor by a difference in absorption of the molybdenum impurity, but by a considerably higher requirement of molybdenum in a medium with nitrate nitrogen. The growth-rate curve and the increasing sporulation of Aspergillus niger with increasing amounts of molybdenum were used in estimating very small amounts of this element in various materials. In culture solution experiments with tomato, barley and oat plants the effect of traces of molybdenum on the growth of these plants was investigated. In good agreement with the results of the experiments with Aspergillus and denitrifying bacteria it could be shown that in the green plant as in these microorganisms molybdenum is acting as a catalyst in nitrate reduction. In experiments with Azotobacter chroococcum and leguminous plants the effect of molybdenum on the fixation of gaseous N/sub 2/ was studied. In culture solutions with pea plants the effect of molybdenum on the nitrogen fixation of the nodules was investigated. In the absence of molybdenum as well as in a complete nutrient medium many nodules were formed. 30 references, 6 figures, 16 tables.

Distribution, congruence, and hotspots of higher plants in China.

Science.gov (United States)

Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

2016-01-11

Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China's Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region's specific conditions.

Root excretions in tobacco plants and possible implications on the Iron nutrition of higher plants

Energy Technology Data Exchange (ETDEWEB)

Wallace, A

1969-01-01

Several pieces of evidence indicate that riboflavin produced in roots and perhaps other compounds produced either in roots or in microorganisms can facilitate either or both the absorption and translocation of iron in higher plants. Riboflavin production and increased iron transport are characteristic of iron-deficient plants, both are decreased by nitrogen deficiency, both evidently can be regulated by a microorganism. When large amounts of iron was transported in the xylem exudate of tobacco, riboflavin was also. An excess of the chelating agent, EDTA, without iron seems to increase the iron uptake from an iron chelate, EDDHA. All these effects are probably related and knowledge of them may help solve iron deficiency problems in horticultural crops.

Engineered jadomycin analogues with altered sugar moieties revealing JadS as a substrate flexible O-glycosyltransferase.

Science.gov (United States)

Li, Liyuan; Pan, Guohui; Zhu, Xifen; Fan, Keqiang; Gao, Wubin; Ai, Guomin; Ren, Jinwei; Shi, Mingxin; Olano, Carlos; Salas, José A; Yang, Keqian

2017-07-01

Glycosyltransferases (GTs)-mediated glycodiversification studies have drawn significant attention recently, with the goal of generating bioactive compounds with improved pharmacological properties by diversifying the appended sugars. The key to achieving glycodiversification is to identify natural and/or engineered flexible GTs capable of acting upon a broad range of substrates. Here, we report the use of a combinatorial biosynthetic approach to probe the substrate flexibility of JadS, the GT in jadomycin biosynthesis, towards different non-native NDP-sugar substrates, enabling us to identify six jadomycin B analogues with different sugar moieties. Further structural engineering by precursor-directed biosynthesis allowed us to obtain 11 new jadomycin analogues. Our results for the first time show that JadS is a flexible O-GT that can utilize both L- and D- sugars as donor substrates, and tolerate structural changes at the C2, C4 and C6 positions of the sugar moiety. JadS may be further exploited to generate novel glycosylated jadomycin molecules in future glycodiversification studies.

Higher plants and UV-B radiation: balancing damage, repair and acclimation

International Nuclear Information System (INIS)

Jansen, M.A.K.; Gaba, V.; Greenberg, B.M.

1998-01-01

Although UV-B is a minor component of sunlight, it has a disproportionately damaging effect on higher plants. Ultraviolet-sensitive targets include DNA, proteins and membranes, and these must be protected for normal growth and development. DNA repair and secondary metabolite accumulation during exposure to UV-B have been characterized in considerable detail, but little is known about the recovery of photosynthesis, induction of free-radical scavenging and morphogenic changes. A future challenge is to elucidate how UV-B-exposed plants balance damage, repair, acclimation and adaptation responses in a photobiologically dynamic environment. (author)

Functional architecture of higher plant photosystem II supercomplexes.

Science.gov (United States)

Caffarri, Stefano; Kouril, Roman; Kereïche, Sami; Boekema, Egbert J; Croce, Roberta

2009-10-07

Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C(2)S(2)M(2) supercomplex were isolated. Characterization by biochemical methods and single particle electron microscopy allowed to relate for the first time the supramolecular organization to the protein content. A projection map of C(2)S(2)M(2) at 12 A resolution was obtained, which allowed determining the location and the orientation of the antenna proteins. Comparison of the supercomplexes obtained from WT and Lhcb-deficient plants reveals the importance of the individual subunits for the supramolecular organization. The functional implications of these findings are discussed and allow redefining previous suggestions on PSII energy transfer, assembly, photoinhibition, state transition and non-photochemical quenching.

The Glycosyltransferases of LPS Core: A Review of Four Heptosyltransferase Enzymes in Context

Directory of Open Access Journals (Sweden)

Joy M. Cote

2017-10-01

Full Text Available Bacterial antibiotic resistance is a rapidly expanding problem in the world today. Functionalization of the outer membrane of Gram-negative bacteria provides protection from extracellular antimicrobials, and serves as an innate resistance mechanism. Lipopolysaccharides (LPS are a major cell-surface component of Gram-negative bacteria that contribute to protecting the bacterium from extracellular threats. LPS is biosynthesized by the sequential addition of sugar moieties by a number of glycosyltransferases (GTs. Heptosyltransferases catalyze the addition of multiple heptose sugars to form the core region of LPS; there are at most four heptosyltransferases found in all Gram-negative bacteria. The most studied of the four is HepI. Cells deficient in HepI display a truncated LPS on their cell surface, causing them to be more susceptible to hydrophobic antibiotics. HepI–IV are all structurally similar members of the GT-B structural family, a class of enzymes that have been found to be highly dynamic. Understanding conformational changes of heptosyltransferases are important to efficiently inhibiting them, but also contributing to the understanding of all GT-B enzymes. Finding new and smarter methods to inhibit bacterial growth is crucial, and the Heptosyltransferases may provide an important model for how to inhibit many GT-B enzymes.

Crystal Structures of Glycosyltransferase UGT78G1 Reveal the Molecular Basis for Glycosylation and Deglycosylation of (Iso)flavonoids

Energy Technology Data Exchange (ETDEWEB)

Modolo, Luzia V.; Li, Lenong; Pan, Haiyun; Blount, Jack W.; Dixon, Richard A.; Wang, Xiaoqiang; (SRNF)

2010-09-21

The glycosyltransferase UGT78G1 from Medicago truncatula catalyzes the glycosylation of various (iso)flavonoids such as the flavonols kaempferol and myricetin, the isoflavone formononetin, and the anthocyanidins pelargonidin and cyanidin. It also catalyzes a reverse reaction to remove the sugar moiety from glycosides. The structures of UGT78G1 bound with uridine diphosphate or with both uridine diphosphate and myricetin were determined at 2.1 {angstrom} resolution, revealing detailed interactions between the enzyme and substrates/products and suggesting a distinct binding mode for the acceptor/product. Comparative structural analysis and mutagenesis identify glutamate 192 as a key amino acid for the reverse reaction. This information provides a basis for enzyme engineering to manipulate substrate specificity and to design effective biocatalysts with glycosylation and/or deglycosylation activity.

Mechanisms of male sterility in higher plants

Energy Technology Data Exchange (ETDEWEB)

Ohta, Yasuo [Tsukuba Univ., Sakura, Ibaraki (Japan)

1982-03-01

The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them.

Role of algae and higher aquatic plants in decontamination of cyanide-containing waters

International Nuclear Information System (INIS)

Timofeeva, S.S.; Kraeva, V.Z.; Men'shikova, O.A.

1986-01-01

Cyanide compounds and especially free cyanides stand out among components of wastewaters of hydrometallurgy, electroforming, and other such enterprises with respect to toxicity and danger for man and fauna of water bodies. In this article data on a study of the regularities of decontamination of cyanide-containing wastewaters by hydrophytes are given, the mechanisms of this process are examined, and the results of testing the hydrobotanical method of treating wastewaters of a goldrecovery plant are examined. The experiments were carried out with hydrophytes from the Angara River, Lake Baikal, and small lakes and ponds in the vicinity of Irkutsk and Tashkent. The series of experiments established that algae and higher aquatic plants are resistant to cyanides. A table shows the kinetic parameters of the removal of cyanide by algae and higher aquatic plants collected in Baikal. Of the multitude of species investigated for detoxifying ability, the most resistant were detected in the experimental basins and the most suitable were charophytes

Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

Science.gov (United States)

Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

2013-01-01

Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

Cloning higher plants from aseptically cultured tissues and cells

Science.gov (United States)

Krikorian, A. D.

1982-01-01

A review of aseptic culture methods for higher plants is presented, which focuses on the existing problems that limit or prevent the full realization of cloning plants from free cells. It is shown that substantial progress in clonal multiplication has been made with explanted stem tips or lateral buds which can be stimulated to produce numerous precocious axillary branches. These branches can then be separated or subdivided and induced to root in order to yield populations of genetically and phenotypically uniorm plantlets. Similarly, undifferentiated calluses can sometimes be induced to form shoots and/or roots adventitiously. Although the cell culture techniques required to produce somatic embryos are presently rudimentary, steady advances are being made in learning how to stimulate formation of somatic or adventive embryos from totipotent cells grown in suspension cultures. It is concluded that many problems exist in the producing and growing of totipotent or morphogenetically competent cell suspensions, but the potential benefits are great.

How common is ecological speciation in plant-feeding insects? A 'Higher' Nematinae perspective

Directory of Open Access Journals (Sweden)

Nyman Tommi

2010-09-01

Full Text Available Abstract Background Ecological speciation is a process in which a transiently resource-polymorphic species divides into two specialized sister lineages as a result of divergent selection pressures caused by the use of multiple niches or environments. Ecology-based speciation has been studied intensively in plant-feeding insects, in which both sympatric and allopatric shifts onto novel host plants could speed up diversification. However, while numerous examples of species pairs likely to have originated by resource shifts have been found, the overall importance of ecological speciation in relation to other, non-ecological speciation modes remains unknown. Here, we apply phylogenetic information on sawflies belonging to the 'Higher' Nematinae (Hymenoptera: Tenthredinidae to infer the frequency of niche shifts in relation to speciation events. Results Phylogenetic trees reconstructed on the basis of DNA sequence data show that the diversification of higher nematines has involved frequent shifts in larval feeding habits and in the use of plant taxa. However, the inferred number of resource shifts is considerably lower than the number of past speciation events, indicating that the majority of divergences have occurred by non-ecological allopatric speciation; based on a time-corrected analysis of sister species, we estimate that a maximum of c. 20% of lineage splits have been triggered by a change in resource use. In addition, we find that postspeciational changes in geographic distributions have led to broad sympatry in many species having identical host-plant ranges. Conclusion Our analysis indicates that the importance of niche shifts for the diversification of herbivorous insects is at present implicitly and explicitly overestimated. In the case of the Higher Nematinae, employing a time correction for sister-species comparisons lowered the proportion of apparent ecology-based speciation events from c. 50-60% to around 20%, but such corrections are

Mechanisms of male sterility in higher plants

International Nuclear Information System (INIS)

Ohta, Yasuo

1982-01-01

The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them. (Kaihara, S.)

Hydroquinone: O-glucosyltransferase from cultivated Rauvolfia cells: enrichment and partial amino acid sequences.

Science.gov (United States)

Arend, J; Warzecha, H; Stöckigt, J

2000-01-01

Plant cell suspension cultures of Rauvolfia are able to produce a high amount of arbutin by glucosylation of exogenously added hydroquinone. A four step purification procedure using anion exchange, hydrophobic interaction, hydroxyapatite-chromatography and chromatofocusing delivered in a yield of 0.5%, an approximately 390 fold enrichment of the involved glucosyltransferase. SDS-PAGE showed a M(r) for the enzyme of 52 kDa. Proteolysis of the pure enzyme with endoproteinase LysC revealed six peptide fragments with 9-23 amino acids which were sequenced. Sequence alignment of the six peptides showed high homologies to glycosyltransferases from other higher plants.

In vitro culture of higher plants as a tool in the propagation of horticultural crops.

NARCIS (Netherlands)

Pierik, R.L.M.

1988-01-01

In vitro culture of higher plants is the culture, under sterile conditions, of plants, seeds, embryos, organs, explants, tissues, cells and protoplasts on nutrient media. This type of culture has shown spectacular development since 1975, resulting in the production and regeneration of viable

Integral use of amaranth starch to obtain cyclodextrin glycosyltransferase, by Bacillus megaterium, to produce β-cyclodextrin.

Directory of Open Access Journals (Sweden)

María Belem Arce-Vázquez

2016-09-01

Full Text Available Cyclodextrin glycosyltransferase (CGTase is an enzyme that produces cyclodextrins (CDs from starch and related carbohydrates, producing a mixture of α-, β-, and γ-CDs in different amounts. CGTase production, mainly by Bacillus sp., depends on fermentation conditions such as pH, temperature, concentration of nutrients, carbon and nitrogen sources, among others. Bacillus megaterium CGTase produces those three types of CDs, however, β-CD should prevail. Although waxy corn starch (CS is used industrially to obtain CGTase and CDs because of its high amylopectin content, alternative sources such as amaranth starch (AS could be used to accomplish those purposes. AS has high susceptibility to the amylolytic activity of CGTase because of its 80% amylopectin content. Therefore, the aim of this work was evaluate the AS as carbon source for CGTase production by B. megaterium in a submerged fermentation. Afterwards, the CGTase was purified partially and its activity to synthesize α-, β- and γ-CDs was evaluated using 1% AS as substrate. B. megaterium produced a 66 kDa CGTase (Topt=50°C; pHopt=8.0, from the early exponential growth phase which lasted 36 h. The maximum CGTase specific activity (106.62±8.33 U/mg protein was obtained after 36 h of culture. CGTase obtained with a Km=0.152 mM and a Vmax=13.4 µM/min yielded 40.47% total CDs using AS which was roughly twice as much as that of corn starch (CS; 24.48%. High costs to produce CDs in the pharmaceutical and food industries might be reduced by using AS because of its higher α-, β- and γ-CDs production (12.81%, 17.94% and 9.92%, respectively in a shorter time than that needed for CS.

The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native Congener Alternanthera sessilis.

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Yue Chen

Full Text Available Plant invasion is one of the major threats to natural ecosystems. Phenotypic plasticity is considered to be important for promoting plant invasiveness. High tolerance of stress can also increase survival of invasive plants in adverse habitats. Limited growth and conservation of carbohydrate are considered to increase tolerance of flooding in plants. However, few studies have examined whether invasive species shows a higher phenotypic plasticity in response to waterlogging or a higher tolerance of waterlogging (lower plasticity than native species. We conducted a greenhouse experiment to compare the growth and morphological and physiological responses to waterlogging of the invasive, clonal, wetland species Alternanthera philoxeroides with those of its co-occurring, native, congeneric, clonal species Alternanthera sessilis. Plants of A. philoxeroides and A. sessilis were subjected to three treatments (control, 0 and 60 cm waterlogging. Both A. philoxeroides and A. sessilis survived all treatments. Overall growth was lower in A. philoxeroides than in A. sessilis, but waterlogging negatively affected the growth of A. philoxeroides less strongly than that of A. sessilis. Alternanthera philoxeroides thus showed less sensitivity of growth traits (lower plasticity and higher waterlogging tolerance. Moreover, the photosynthetic capacity of A. philoxeroides was higher than that of A. sessilis during waterlogging. Alternanthera philoxeroides also had higher total non-structural and non-soluble carbohydrate concentrations than A. sessilis at the end of treatments. Our results suggest that higher tolerance to waterlogging and higher photosynthetic capacity may partly explain the invasion success of A. philoxeroides in wetlands.

DNA repair in mutagen-injured higher plants

International Nuclear Information System (INIS)

Veleminsky, J.; Gichner, T.

1978-01-01

Data are summarized proving the occurrence of photoreactivation of UV-induced pyrimidine dimers in cells of Nicotiana tabucum, Gingko and carrot, the excision of dimers in cells of Nicotiana tabacum, Gingko and carrot, the excision of dimers in protoplasts of carrot and in embryos of Lathyrus sativus, and the repair of DNA single-strand breaks induced in carrot protoplasts and barley embryonic cells by ionizing radiation. In irradiated barley embryos the unscheduled DNA synthesis and higher accessibility of induced primers to DNA polymerase I of E. coli were observed preferentially in G 1 cells with diffused chromatin. These reactions were inhibited by caffeine and EDTA. Unscheduled DNA synthesis was also observed in synchronized irradiated root cuttings of Vicia faba and in barley embryos treated with 4-nitroquinoline oxide, the latter being inhibited by caffeine and hydroxyurea. Repair synthesis was also established in barley embryos treated with mutagenic N-methyl-N-nitrosourea under conditions that postponed the onset of germination after the treatment. The same conditions enhanced the repair of DNA single-strand breaks induced by this mutagen and several other monofunctional alkylating compounds. From tissues of barley and of Phaseolus multiflorus, endonucleases for apurinic sites were isolated and characterized. Some of them are located in chromatin, others in chloroplasts. The relation between DNA repair and genetic effects of mutagens in higher plants is also discussed. (Auth.)

Higher photosynthesis, nutrient- and energy-use efficiencies contribute to invasiveness of exotic plants in a nutrient poor habitat in northeast China.

Science.gov (United States)

Liu, Ming-Chao; Kong, De-Liang; Lu, Xiu-Rong; Huang, Kai; Wang, Shuo; Wang, Wei-Bin; Qu, Bo; Feng, Yu-Long

2017-08-01

The roles of photosynthesis-related traits in invasiveness of introduced plant species are still not well elucidated, especially in nutrient-poor habitats. In addition, little effort has been made to determine the physiological causes and consequences of the difference in these traits between invasive and native plants. To address these problems, we compared the differences in 16 leaf functional traits related to light-saturated photosynthetic rate (P max ) between 22 invasive and native plants in a nutrient-poor habitat in northeast China. The invasive plants had significantly higher P max , photosynthetic nitrogen- (PNUE), phosphorus- (PPUE), potassium- (PKUE) and energy-use efficiencies (PEUE) than the co-occurring natives, while leaf nutrient concentrations, construction cost (CC) and specific leaf area were not significantly different between the invasive and native plants. The higher PNUE contributed to higher P max for the invasive plants, which in turn contributed to higher PPUE, PKUE and PEUE. CC changed independently with other traits such as P max , PNUE, PPUE, PKUE and PEUE, showing two trait dimensions, which may facilitate acclimation to multifarious niche dimensions. Our results indicate that the invasive plants have a superior resource-use strategy, i.e. higher photosynthesis under similar resource investments, contributing to invasion success in the barren habitat. © 2017 Scandinavian Plant Physiology Society.

Plants experiencing chronic internal exposure to ionizing radiation exhibit higher frequency of homologous recombination than acutely irradiated plants

Energy Technology Data Exchange (ETDEWEB)

Kovalchuk, O.; Kovalchuk, I.; Hohn, B. [Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel (Switzerland); Arkhipov, A. [Chernobyl Scientific and Technical Center of International Research, Shkolnaya Str. 6, 255620 Chernobyl (Ukraine); Barylyak, I.; Karachov, I. [Ukrainian Scientific Genetics Center, Popudrenko Str. 50, 253660 Kiev (Ukraine); Titov, V. [Ivano-Frankivsk State Medical Academy, Galitska Str.2, 284000 Ivano-Frankivsk (Ukraine)

2000-04-03

different chemical composition, but equal radioactivity, exhibited different levels of HR, dependent upon the absorbed dose of radiation. Remarkably, we observed a much higher frequency of HR in plants exposed to chronic irradiation when compared to acutely irradiated plants. Although acute application of 0.1-0.5 Gy did not lead to an increase of frequency of HR, the chronic exposure of the plants to several orders of magnitude lower dose of 200 {mu}Gy led to a 5-6-fold induction of the frequency of HR as compared to the control.

Evolutionary history and stress regulation of the lectin superfamily in higher plants

Directory of Open Access Journals (Sweden)

Ramachandran Srinivasan

2010-03-01

Full Text Available Abstract Background Lectins are a class of carbohydrate-binding proteins. They play roles in various biological processes. However, little is known about their evolutionary history and their functions in plant stress regulation. The availability of full genome sequences from various plant species makes it possible to perform a whole-genome exploration for further understanding their biological functions. Results Higher plant genomes encode large numbers of lectin proteins. Based on their domain structures and phylogenetic analyses, a new classification system has been proposed. In this system, 12 different families have been classified and four of them consist of recently identified plant lectin members. Further analyses show that some of lectin families exhibit species-specific expansion and rapid birth-and-death evolution. Tandem and segmental duplications have been regarded as the major mechanisms to drive lectin expansion although retrogenes also significantly contributed to the birth of new lectin genes in soybean and rice. Evidence shows that lectin genes have been involved in biotic/abiotic stress regulations and tandem/segmental duplications may be regarded as drivers for plants to adapt various environmental stresses through duplication followed by expression divergence. Each member of this gene superfamily may play specialized roles in a specific stress condition and function as a regulator of various environmental factors such as cold, drought and high salinity as well as biotic stresses. Conclusions Our studies provide a new outline of the plant lectin gene superfamily and advance the understanding of plant lectin genes in lineage-specific expansion and their functions in biotic/abiotic stress-related developmental processes.

Arabinogalactan glycosyltransferases target to a unique subcellular compartment that may function in unconventional secretion in plants

DEFF Research Database (Denmark)

Poulsen, Christian Peter; Dilokpimol, Adiphol; Mouille, Grégory

2014-01-01

-glycosylation enzymes rarely colocalized (3-18%), implicating a role of the small compartments in a part of arabinogalactan (O-glycan) biosynthesis rather than N-glycan processing. The dual localization of AtGALT31A was also observed for fluorescently tagged AtGALT31A stably expressed in an Arabidopsis atgalt31a mutant...... colocalized with neither SYP61 (syntaxin of plants 61), a marker for trans-Golgi network (TGN), nor FM4-64-stained endosomes. However, 41% colocalized with EXO70E2 (Arabidopsis thaliana exocyst protein Exo70 homolog 2), a marker for exocyst-positive organelles, and least affected by Brefeldin A and Wortmannin....... Taken together, AtGALT31A localized to small compartments that are distinct from the Golgi apparatus, the SYP61-localized TGN, FM4-64-stained endosomes and Wortmannin-vacuolated prevacuolar compartments, but may be part of an unconventional protein secretory pathway represented by EXO70E2 in plants....

Regulation of chloroplast number and DNA synthesis in higher plants. Final report

Energy Technology Data Exchange (ETDEWEB)

Mullet, J.E.

1995-11-10

The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

Base substitution mutations in uridinediphosphate-dependent glycosyltransferase 76G1 gene of Stevia rebaudiana causes the low levels of rebaudioside A: mutations in UGT76G1, a key gene of steviol glycosides synthesis.

Science.gov (United States)

Yang, Yong-Heng; Huang, Su-Zhen; Han, Yu-Lin; Yuan, Hai-Yan; Gu, Chun-Sun; Zhao, Yan-Hai

2014-07-01

Steviol glycosides, extracted from the leaves of Stevia rebaudiana (Bert) Bertoni, are calorie-free sugar substitute of natural origin with intensely sweet (Boileau et al., 2012). Stevioside and rebaudioside A are the two main kinds of the diterpenic glycosides. We analyzed the concentration of stevioside and rebaudioside A in Stevia leaves of about 500 samples (hybrid progenies) and discovered a mutation plant "Z05" with very low levels of rebaudioside A. Because UGT76G1, a uridinediphosphate-dependent glycosyltransferases, is responsible for the conversion from stevioside to rebaudioside A (Richman et al., 2005), so mutation identification was done by sequencing the candidate gene, UGT76G1. In this study molecular analysis of two strains revealed a heterozygotic nonsense mutation of c.389T > G (p.L121X) in UGT76G1. Meanwhile, we found some amino acid substitutions significant change the protein structure. And the difference of enzyme activity between two strains proved the lack of functionality of UGT76G1 of the mutation "Z05". So the nonsense mutation and amino acid substitution mutation resulted in the low levels of rebaudioside A. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The cytoskeleton and gravitropism in higher plants

Science.gov (United States)

Blancaflor, Elison B.

2002-01-01

The cellular and molecular mechanisms underlying the gravitropic response of plants have continued to elude plant biologists despite more than a century of research. Lately there has been increased attention on the role of the cytoskeleton in plant gravitropism, but several controversies and major gaps in our understanding of cytoskeletal involvement in gravitropism remain. A major question in the study of plant gravitropism is how the cytoskeleton mediates early sensing and signal transduction events in plants. Much has been made of the actin cytoskeleton as the cellular structure that sedimenting amyloplasts impinge upon to trigger the downstream signaling events leading to the bending response. There is also strong molecular and biochemical evidence that the transport of auxin, an important player in gravitropism, is regulated by actin. Organizational changes in microtubules during the growth response phase of gravitropism have also been well documented, but the significance of such reorientations in controlling differential cellular growth is unclear. Studies employing pharmacological approaches to dissect cytoskeletal involvement in gravitropism have led to conflicting results and therefore need to be interpreted with caution. Despite the current controversies, the revolutionary advances in molecular, biochemical, and cell biological techniques have opened up several possibilities for further research into this difficult area. The myriad proteins associated with the plant cytoskeleton that are being rapidly characterized provide a rich assortment of candidate regulators that could be targets of the gravity signal transduction chain. Cytoskeletal and ion imaging in real time combined with mutant analysis promises to provide a fresh start into this controversial area of research.

Higher plant modelling for life support applications: first results of a simple mechanistic model

Science.gov (United States)

Hezard, Pauline; Dussap, Claude-Gilles; Sasidharan L, Swathy

2012-07-01

In the case of closed ecological life support systems, the air and water regeneration and food production are performed using microorganisms and higher plants. Wheat, rice, soybean, lettuce, tomato or other types of eatable annual plants produce fresh food while recycling CO2 into breathable oxygen. Additionally, they evaporate a large quantity of water, which can be condensed and used as potable water. This shows that recycling functions of air revitalization and food production are completely linked. Consequently, the control of a growth chamber for higher plant production has to be performed with efficient mechanistic models, in order to ensure a realistic prediction of plant behaviour, water and gas recycling whatever the environmental conditions. Purely mechanistic models of plant production in controlled environments are not available yet. This is the reason why new models must be developed and validated. This work concerns the design and test of a simplified version of a mathematical model coupling plant architecture and mass balance purposes in order to compare its results with available data of lettuce grown in closed and controlled chambers. The carbon exchange rate, water absorption and evaporation rate, biomass fresh weight as well as leaf surface are modelled and compared with available data. The model consists of four modules. The first one evaluates plant architecture, like total leaf surface, leaf area index and stem length data. The second one calculates the rate of matter and energy exchange depending on architectural and environmental data: light absorption in the canopy, CO2 uptake or release, water uptake and evapotranspiration. The third module evaluates which of the previous rates is limiting overall biomass growth; and the last one calculates biomass growth rate depending on matter exchange rates, using a global stoichiometric equation. All these rates are a set of differential equations, which are integrated with time in order to provide

Preliminary Modelling of Mass Flux at the Surface of Plant Leaves within the MELiSSA Higher Plant Compartments

Science.gov (United States)

Holmberg, Madeleine; Paille, Christel; Lasseur, Christophe

The ESA project Micro Ecological Life Support System Alternative (MELiSSA) is an ecosystem of micro-organisms and higher plants, constructed with the objective of being operated as a tool to understand artificial ecosystems to be used for a long-term or permanent manned planetary base (e.g. Moon or Mars). The purpose of such a system is to provide for generation of food, water recycling, atmospheric regeneration and waste management within defined standards of quality and reliability. As MELiSSA consists of individual compartments which are connected to each other, the robustness of the system is fully dependent on the control of each compartment, as well as the flow management between them. Quality of consumables and reliability of the ecosystem rely on the knowledge, understanding and control of each of the components. This includes the full understanding of all processes related to the higher plants. To progress in that direction, this paper focuses on the mechanical processes driving the gas and liquid exchanges between the plant leaf and its environment. The process responsible for the mass transfer on the surface of plant leaves is diffusion. The diffusion flux is dependent on the behaviour of the stoma of the leaf and also on the leaf boundary layer (BL). In this paper, the physiology of the leaf is briefly examined in order to relate parameters such as light quality, light quantity, CO2 concentration, temperature, leaf water potential, humidity, vapour pressure deficit (VPD) gradients and pollutants to the opening or closing of stomata. The diffusion process is described theoretically and the description is compared to empirical approaches. The variables of the BL are examined and the effect airflow in the compartment has on the BL is investigated. Also presented is the impact changes in different environmental parameters may have on the fluid exchanges. Finally, some tests, to evaluate the accuracy of the concluded model, are suggested.

Features of fatty acid synthesis in higher plants

Energy Technology Data Exchange (ETDEWEB)

Yamada, M [Tokyo Univ. (Japan). Coll. of General Education; Nakamura, Y

1975-07-01

In the biosynthesis of fatty acid in the presence of /sup 3/H/sub 2/O, /sup 3/H is incorporated into the hydrocarbon chain of the fatty acid. The features in the fatty acid synthesis of higher plants were investigated by applying /sup 3/H/sub 2/O method to the measurement of the ability of spinach leaves synthesizing fatty acid. Sucrose, acetate, pyruvate, PGA, PEP, OAA, citrate, etc. were employed as the substrates of fatty acid synthesis to trace the process of synthesis of each fatty acid. The demand of various cofactors related to the ability of spinach chloroplast fatty acid synthesizing was also examined. Light dependence of the fatty acid synthesis of chloroplast as well as the influences of N,N'-dicyclohexyl carbodiimide, carbonylcyanide-4-trifluoromethoxy phenyl hydrazone and NH/sub 4/Cl were discussed. The results were compared with the reports on the fatty acid synthesis of avocado pear, castor bean, etc.

Molecular characterization of UGT94F2 and UGT86C4, two glycosyltransferases from Picrorhiza kurrooa: comparative structural insight and evaluation of substrate recognition.

Directory of Open Access Journals (Sweden)

Wajid Waheed Bhat

Full Text Available Uridine diphosphate glycosyltransferases (UGTs are pivotal in the process of glycosylation for decorating natural products with sugars. It is one of the versatile mechanisms in determining chemical complexity and diversity for the production of suite of pharmacologically active plant natural products. Picrorhiza kurrooa is a highly reputed medicinal herb known for its hepato-protective properties which are attributed to a novel group of iridoid glycosides known as picrosides. Although the plant is well studied in terms of its pharmacological properties, very little is known about the biosynthesis of these important secondary metabolites. In this study, we identified two family-1 glucosyltransferases from P. kurrooa. The full length cDNAs of UGT94F4 and UGT86C4 contained open reading frames of 1455 and 1422 nucleotides, encoding polypeptides of 484 and 473 amino acids respectively. UGT94F2 and UGT86C4 showed differential expression pattern in leaves, rhizomes and inflorescence. To elucidate whether the differential expression pattern of the two Picrorhiza UGTs correlate with transcriptional regulation via their promoters and to identify elements that could be recognized by known iridoid-specific transcription factors, upstream regions of each gene were isolated and scanned for putative cis-regulatory elements. Interestingly, the presence of cis-regulatory elements within the promoter regions of each gene correlated positively with their expression profiles in response to different phytohormones. HPLC analysis of picrosides extracted from different tissues and elicitor-treated samples showed a significant increase in picroside levels, corroborating well with the expression profile of UGT94F2 possibly indicating its implication in picroside biosynthesis. Using homology modeling and molecular docking studies, we provide an insight into the donor and acceptor specificities of both UGTs identified in this study. UGT94F2 was predicted to be an iridoid

Research and higher education background of the Paks Nuclear Power Plant, Hungary. Past and present

International Nuclear Information System (INIS)

Csom, Gy.

2002-01-01

The connection of the Paks Nuclear Power Plant, Hungary, with research and development as well as with higher education is discussed. The main research areas include reactor physics, thermohydraulics, radiochemistry and radiochemical analysis, electronics and nuclear instruments, computers, materials science. The evolution of relations with higher education in Hungary and the PNPP is presented, before and after the installation of the various units. (R.P.)

Plant species richness sustains higher trophic levels of soil nematode communities after consecutive environmental perturbations.

Science.gov (United States)

Cesarz, Simone; Ciobanu, Marcel; Wright, Alexandra J; Ebeling, Anne; Vogel, Anja; Weisser, Wolfgang W; Eisenhauer, Nico

2017-07-01

The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.

Science.gov (United States)

Thwala, Melusi; Klaine, Stephen J; Musee, Ndeke

2016-07-01

The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC. © 2016 SETAC.

The plant secretory pathway seen through the lens of the cell wall.

Science.gov (United States)

van de Meene, A M L; Doblin, M S; Bacic, Antony

2017-01-01

Secretion in plant cells is often studied by looking at well-characterised, evolutionarily conserved membrane proteins associated with particular endomembrane compartments. Studies using live cell microscopy and fluorescent proteins have illuminated the highly dynamic nature of trafficking, and electron microscopy studies have resolved the ultrastructure of many compartments. Biochemical and molecular analyses have further informed about the function of particular proteins and endomembrane compartments. In plants, there are over 40 cell types, each with highly specialised functions, and hence potential variations in cell biological processes and cell wall structure. As the primary function of secretion in plant cells is for the biosynthesis of cell wall polysaccharides and apoplastic transport complexes, it follows that utilising our knowledge of cell wall glycosyltransferases (GTs) and their polysaccharide products will inform us about secretion. Indeed, this knowledge has led to novel insights into the secretory pathway, including previously unseen post-TGN secretory compartments. Conversely, our knowledge of trafficking routes of secretion will inform us about polarised and localised deposition of cell walls and their constituent polysaccharides/glycoproteins. In this review, we look at what is known about cell wall biosynthesis and the secretory pathway and how the different approaches can be used in a complementary manner to study secretion and provide novel insights into these processes.

Cyclodextrin glycosyltransferase from Bacillus licheniformis: optimization of production and its properties Cyclodextrina glycosyltransferase de Bacillus licheniformis: otimização da produção e suas propriedades

Directory of Open Access Journals (Sweden)

Paulo Roberto Martins Bonilha

2006-09-01

Full Text Available Cyclodextrin glycosyltransferase (EC 2.4.1.19 is an enzyme that produces cyclodextrins from starch via an intramolecular transglycosylation reaction. An alkalophilic Bacillus strain, isolated from cassava peels, was identified as Bacillus licheniformis. CGTase production by this strain was better when potato starch was used as carbon source, followed by cassava starch and amylopectin. Glucose and amylose, on the other hand, acted as synthesis repressors. When the cultivation was supplemented with sodium ions and had the pH adjusted between 6.0 and 9.0, the microorganism maintained the growth and enzyme production capacity. This data is interesting because it contradicts the concept that alkalophilic microorganisms do not grow in this pH range. After ultrafiltration-centrifugation, one protein of 85.2 kDa with CGTase activity was isolated. This protein was identified in plates with starch and phenolphthalein. Determination of the optimum temperature showed higher activities at 25ºC and 55ºC, indicating the possible presence of more than one CGTase in the culture filtrate. Km and Vmax values were 1.77 mg/mL and 0.0263 U/mg protein, respectively, using potato starch as substrate.Ciclodextrina glicosiltransferase (EC 2.4.1.19 é uma enzima que produz ciclodextrinas a partir de amido via transglicosilação intramolecular. Uma cepa de Bacillus alcalofílico, isolada de cascas de mandioca, foi identificada como Bacillus licheniformis. A produção de CGTase por esta cepa foi melhor quando amido de batata foi utilizado como fonte de carbono, seguido por amido de mandioca e amilopectina. Glicose e amilose, por outro lado, atuaram como repressor de síntese desta enzima. Quando o cultivo foi suplementado com íons sódio e teve o pH ajustado entre 6,0 e 9,0, o microrganismo manteve a capacidade de crescimento e de produção da enzima. Este dado é interessante pois contraria o conceito de que microrganismos alcalofílicos não apresentam crescimento

Production characteristics of the "higher plants-soil-like substrate" system as an element of the bioregenerative life support system

Science.gov (United States)

Velichko, V. V.; Tikhomirov, A. A.; Ushakova, S. A.; Tikhomirova, N. A.; Shihov, V. N.; Tirranen, L. S.; Gribovskaya, I. A.

2013-01-01

The study addresses the possibility of long-duration operation of a higher plant conveyor, using a soil-like substrate (SLS) as the root zone. Chufa (Cyperus esculentus L.), radish (Raphanus sativus L.), and lettuce (Lactuca sativa L.) were used as study material. A chufa community consisting of 4 age groups and radish and lettuce communities consisting of 2 age groups were irrigated with a nutrient solution, which contained mineral elements extracted from the SLS. After each harvest, inedible biomass of the harvested plants and inedible biomasses of wheat and saltwort were added to the SLS. The amounts of the inedible biomasses of wheat and saltwort to be added to the SLS were determined based on the nitrogen content of the edible mass of harvested plants. CO2 concentration in the growth chamber was maintained within the range of 1100-1700 ppm. The results of the study show that higher plants can be grown quite successfully using the proposed process of plant waste utilization in the SLS. The addition of chufa inedible biomass to the SLS resulted in species-specific inhibition of growth of both cultivated crops and microorganisms in the "higher plants - SLS" system. There were certain differences between the amounts of some mineral elements removed from the SLS with the harvested edible biomass and those added to it with the inedible biomasses of wheat and saltwort.

Regulation of phosphate starvation responses in higher plants.

Science.gov (United States)

Yang, Xiao Juan; Finnegan, Patrick M

2010-04-01

Phosphorus (P) is often a limiting mineral nutrient for plant growth. Many soils worldwide are deficient in soluble inorganic phosphate (P(i)), the form of P most readily absorbed and utilized by plants. A network of elaborate developmental and biochemical adaptations has evolved in plants to enhance P(i) acquisition and avoid starvation. Controlling the deployment of adaptations used by plants to avoid P(i) starvation requires a sophisticated sensing and regulatory system that can integrate external and internal information regarding P(i) availability. In this review, the current knowledge of the regulatory mechanisms that control P(i) starvation responses and the local and long-distance signals that may trigger P(i) starvation responses are discussed. Uncharacterized mutants that have P(i)-related phenotypes and their potential to give us additional insights into regulatory pathways and P(i) starvation-induced signalling are also highlighted and assessed. An impressive list of factors that regulate P(i) starvation responses is now available, as is a good deal of knowledge regarding the local and long-distance signals that allow a plant to sense and respond to P(i) availability. However, we are only beginning to understand how these factors and signals are integrated with one another in a regulatory web able to control the range of responses demonstrated by plants grown in low P(i) environments. Much more knowledge is needed in this agronomically important area before real gains can be made in improving P(i) acquisition in crop plants.

Identification of a root-specific glycosyltransferase from Arabidopsis ...

Indian Academy of Sciences (India)

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antimicrobial or pesticidal proteins in certain tissues of the plant which are the sites ... interest for engineering resistance against root nematodes. (Huang et al .... animals and plants to identify and study genes based on their expression pattern ...

[Gene deletion and functional analysis of the heptyl glycosyltransferase (waaF) gene in Vibrio parahemolyticus O-antigen cluster].

Science.gov (United States)

Zhao, Feng; Meng, Songsong; Zhou, Deqing

2016-02-04

To construct heptyl glycosyltransferase gene II (waaF) gene deletion mutant of Vibrio parahaemolyticus, and explore the function of the waaF gene in Vibrio parahaemolyticus. The waaF gene deletion mutant was constructed by chitin-based transformation technology using clinical isolates, and then the growth rate, morphology and serotypes were identified. The different sources (O3, O5 and O10) waaF gene complementations were constructed through E. coli S17λpir strains conjugative transferring with Vibrio parahaemolyticus, and the function of the waaF gene was further verified by serotypes. The waaF gene deletion mutant strain was successfully constructed and it grew normally. The growth rate and morphology of mutant were similar with the wild type strains (WT), but the mutant could not occurred agglutination reaction with O antisera. The O3 and O5 sources waaF gene complementations occurred agglutination reaction with O antisera, but the O10 sources waaF gene complementations was not. The waaF gene was related with O-antigen synthesis and it was the key gene of O-antigen synthesis pathway in Vibrio parahaemolyticus. The function of different sources waaF gene were not the same.

Uptake and metabolism of diclofenac in Typha latifolia--how plants cope with human pharmaceutical pollution.

Science.gov (United States)

Bartha, Bernadett; Huber, Christian; Schröder, Peter

2014-10-01

The fate of pharmaceuticals in our environment is a very important issue for environmental and health research. Although these substances have been detected in environmental compartments in low concentration until now, they will pose considerable environmental risk to ecosystems, animals and human due to their biological activity. Alternative plant based removal technologies that make use of some potential wetland species like Phragmites or Typha within traditional wastewater treatment plants have to be established to cope with this "new generation" of pollutants. We investigated uptake and translocation of diclofenac (1mgl(-1)) in the macrophyte Typha latifolia L. during one week exposure in greenhouse experiments. Detoxification products and involved key enzymatic processes were identified. We also examined the oxidative stress induced by the treatment and the defense capacity of the plants. Rapid uptake and effective metabolism were observed, where glycoside and glutathione conjugates represent dominant metabolites. Up to seven-fold induction of glycosyltransferase activity was observed in roots, but not in shoots. Glutathione S-transferase activity was also induced, but to a lower extent. The activity changes of defense enzymes points to oxidative stress in the plants. Our results show that human pharmaceuticals can be metabolized by plants similar to xenobiotics, but that similarities to human metabolism are limited. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Higher plant acclimation to solar ultraviolet-B radiation

International Nuclear Information System (INIS)

Robberecht, R.

1981-01-01

The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal uv attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from uv-B exposure, on plant sensitivity to uv radiation, and (3) the platicity of these changes in the epidermis leading to plant acclimation to uv-B radiation. A mechanism of uv-B attenuation, possibly involving the biosynthesis of uv-absorbing flavonoid compounds in the epidermis and mesophyll under the stress of uv-B radiation, and a subsequent increase in the uv-B attenuation capacity of the epidermis, is suggested. The degree of plant sensitivity and acclimation to natural and intensified solar uv-B radiation may involve a dynamic balance between the capacity for uv-B attenuation and uv-radiation-repair mechanisms in the leaf

Low-temperature conditioning of "seed" cloves enhances the expression of phenolic metabolism related genes and anthocyanin content in 'Coreano' garlic (Allium sativum) during plant development.

Science.gov (United States)

Dufoo-Hurtado, Miguel D; Zavala-Gutiérrez, Karla G; Cao, Cong-Mei; Cisneros-Zevallos, Luis; Guevara-González, Ramón G; Torres-Pacheco, Irineo; Vázquez-Barrios, M Estela; Rivera-Pastrana, Dulce M; Mercado-Silva, Edmundo M

2013-11-06

Low-temperature conditioning of garlic "seed" cloves accelerated the development of the crop cycle, decreased plant growth, and increased the synthesis of phenolic compounds and anthocyanins in the outer scale leaves of the bulbs at harvest time, leading to 3-fold content increase compared with those conditioned at room temperature. Cold conditioning of "seed" cloves also altered the anthocyanin profile during bulb development and at harvest. Two new anthocyanins are reported for the first time in garlic. The high phenolics and anthocyanin contents in bulbs of plants generated from "seed" cloves conditioned at 5 °C for 5 weeks were preceded by overexpression of some putative genes of the phenolic metabolism [6-fold for phenylalanine ammonia lyase (PAL)] and anthocyanin synthesis [1-fold for UDP-sugar:flavonoid 3-O-glycosyltransferase (UFGT)] compared with those conditioned at room temperature.

Two bee-pollinated plant species show higher seed production when grown in gardens compared to arable farmland.

Directory of Open Access Journals (Sweden)

John Cussans

2010-07-01

Full Text Available Insect pollinator abundance, in particular that of bees, has been shown to be high where there is a super-abundance of floral resources; for example in association with mass-flowering crops and also in gardens where flowering plants are often densely planted. Since land management affects pollinator numbers, it is also likely to affect the resultant pollination of plants growing in these habitats. We hypothesised that the seed or fruit set of two plant species, typically pollinated by bumblebees and/or honeybees might respond in one of two ways: 1 pollination success could be reduced when growing in a floriferous environment, via competition for pollinators, or 2 pollination success could be enhanced because of increased pollinator abundance in the vicinity.We compared the pollination success of experimental plants of Glechoma hederacea L. and Lotus corniculatus L. growing in gardens and arable farmland. On the farms, the plants were placed either next to a mass-flowering crop (oilseed rape, Brassica napus L. or field beans, Vicia faba L. or next to a cereal crop (wheat, Triticum spp.. Seed set of G. hederacea and fruit set of L. corniculatus were significantly higher in gardens compared to arable farmland. There was no significant difference in pollination success of G. hederacea when grown next to different crops, but for L. corniculatus, fruit set was higher in the plants growing next to oilseed rape when the crop was in flower.The results show that pollination services can limit fruit set of wild plants in arable farmland, but there is some evidence that the presence of a flowering crop can facilitate their pollination (depending on species and season. We have also demonstrated that gardens are not only beneficial to pollinators, but also to the process of pollination.

Higher accumulation of F1-V fusion recombinant protein in plants after induction of protein body formation.

Science.gov (United States)

Alvarez, M Lucrecia; Topal, Emel; Martin, Federico; Cardineau, Guy A

2010-01-01

Improving foreign protein accumulation is crucial for enhancing the commercial success of plant-based production systems since product yields have a major influence on process economics. Cereal grain evolved to store large amounts of proteins in tightly organized aggregates. In maize, gamma-Zein is the major storage protein synthesized by the rough endoplasmic reticulum (ER) and stored in specialized organelles called protein bodies (PB). Zera (gamma-Zein ER-accumulating domain) is the N-terminal proline-rich domain of gamma-zein that is sufficient to induce the assembly of PB formation. Fusion of the Zera domain to proteins of interest results in assembly of dense PB-like, ER-derived organelles, containing high concentration of recombinant protein. Our main goal was to increase recombinant protein accumulation in plants in order to enhance the efficiency of orally-delivered plant-made vaccines. It is well known that oral vaccination requires substantially higher doses than parental formulations. As a part of a project to develop a plant-made plague vaccine, we expressed our model antigen, the Yersinia pestis F1-V antigen fusion protein, with and without a fused Zera domain. We demonstrated that Zera-F1-V protein accumulation was at least 3x higher than F1-V alone when expressed in three different host plant systems: Ncotiana benthamiana, Medicago sativa (alfalfa) and Nicotiana tabacum NT1 cells. We confirmed the feasibility of using Zera technology to induce protein body formation in non-seed tissues. Zera expression and accumulation did not affect plant development and growth. These results confirmed the potential exploitation of Zera technology to substantially increase the accumulation of value-added proteins in plants.

Absorption and conversion of nitrogen dioxide by higher plants

International Nuclear Information System (INIS)

Durmishidze, S.V.; Nutsubidze, N.N.

1976-01-01

An investigation was performed to study the ability of plants to absorb and metabolize NO 2 , as well as to reduce and incorporate nitrogen into amino acid molecules. Experiments on the absorption of NO 2 labeled with 15 N were conducted in special chambers, both on whole plants and on fresh-cut branches. NO 2 was used in various concentrations from 0.01 to 5% of the volume. The exposure of the experiments ranged from 5 min to 7 days, involving more than 60 species of perennial and annual plants. The processes of assimilation and conversion of NO 2 from the air to amino acids by plants are related. The conversion scheme showed close association with physiological state of the plant and with external factors of its vital activity. It is conceivable that plants that intensively absorb and convert oxides of nitrogen and give a large biomass can be used for the purification air

Phytate (Inositol Hexakisphosphate in Soil and Phosphate Acquisition from Inositol Phosphates by Higher Plants. A Review

Directory of Open Access Journals (Sweden)

Jörg Gerke

2015-05-01

Full Text Available Phosphate (P fixation to the soil solid phase is considered to be important for P availability and is often attributed to the strong binding of orthophosphate anion species. However, the fixation and subsequent immobilization of inositolhexa and pentaphosphate isomers (phytate in soil is often much stronger than that of the orthosphate anion species. The result is that phytate is a main organic P form in soil and the dominating form of identifiable organic P. The reasons for the accumulation are not fully clear. Two hypothesis can be found in the literature in the last 20 years, the low activity of phytase (phosphatases in soil, which makes phytate P unavailable to the plant roots, and, on the other hand, the strong binding of phytate to the soil solid phase with its consequent stabilization and accumulation in soil. The hypothesis that low phytase activity is responsible for phytate accumulation led to the development of genetically modified plant genotypes with a higher expression of phytase activity at the root surface and research on the effect of a higher phytate activity on P acquisition. Obviously, this hypothesis has a basic assumption, that the phytate mobility in soil is not the limiting step for P acquisition of higher plants from soil phytate. This assumption is, however, not justified considering the results on the sorption, immobilization and fixation of phytate to the soil solid phase reported in the last two decades. Phytate is strongly bound, and the P sorption maximum and probably the sorption strength of phytate P to the soil solid phase is much higher, compared to that of orthophosphate P. Mobilization of phytate seems to be a promising step to make it available to the plant roots. The excretion of organic acid anions, citrate and to a lesser extend oxalate, seems to be an important way to make phytate P available to the plants. Phytase activity at the root surface seems not be the limiting step in P acquisition from phytate

The re-assimilation of ammonia produced by photorespiration and the nitrogen economy of C3 higher plants.

Science.gov (United States)

Keys, Alfred J

2006-02-01

Photorespiration involves the conversion of glycine to serine with the release of ammonia and CO(2). In C(3) terrestrial higher plants the flux through glycine and serine is so large that it results in the production of ammonia at a rate far exceeding that from reduction of new nitrogen entering the plant. The photorespiratory nitrogen cycle re-assimilates this ammonia using the enzymes glutamine synthetase and glutamine:2-oxoglutarateaminotransferase.

Structure of the higher plant light harvesting complex I: In vivo characterization and structural interdependence of the Lhca proteins

NARCIS (Netherlands)

Klimmek, F.; Ganeteg, U.; Ihalainen, J.A.; van Roon, H.; Jensen, P.E.; Scheller, H.V.; Dekker, J.P.; Jansson, S.

2005-01-01

We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding

Recent advances on the posttranslational modifications of EXTs and their roles in plant cell walls

DEFF Research Database (Denmark)

Velasquez, Melina; Salter, Juan Salgado; Dorosz, Javier Gloazzo

2012-01-01

The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O......-glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4......-hydroxylases (P4Hs), the glycosyltransferases that transfer arabinose units (named arabinosyltransferases, AraTs), and the one responsible for transferring a single galactose (galactosyltransferase, GalT) on the protein EXT backbones. We discuss the effects of posttranslational modifications on the structure...

Cadmium against higher plant photosynthesis - a variety of effects and where do they possibly come from?

International Nuclear Information System (INIS)

Krupa, Z.

1999-01-01

The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosynthetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism. (orig.)

Integrated process design for biocatalytic synthesis by a Leloir Glycosyltransferase: UDP-glucose production with sucrose synthase.

Science.gov (United States)

Schmölzer, Katharina; Lemmerer, Martin; Gutmann, Alexander; Nidetzky, Bernd

2017-04-01

Nucleotide sugar-dependent ("Leloir") glycosyltransferases (GTs), represent a new paradigm for the application of biocatalytic glycosylations to the production of fine chemicals. However, it remains to be shown that GT processes meet the high efficiency targets of industrial biotransformations. We demonstrate in this study of uridine-5'-diphosphate glucose (UDP-glc) production by sucrose synthase (from Acidithiobacillus caldus) that a holistic process design, involving coordinated development of biocatalyst production, biotransformation, and downstream processing (DSP) was vital for target achievement at ∼100 g scale synthesis. Constitutive expression in Escherichia coli shifted the recombinant protein production mainly to the stationary phase and enhanced the specific enzyme activity to a level (∼480 U/g cell dry weight ) suitable for whole-cell biotransformation. The UDP-glc production had excellent performance metrics of ∼100 g product /L, 86% yield (based on UDP), and a total turnover number of 103 g UDP-glc /g cell dry weight at a space-time yield of 10 g/L/h. Using efficient chromatography-free DSP, the UDP-glc was isolated in a single batch with ≥90% purity and in 73% isolated yield. Overall, the process would allow production of ∼0.7 kg of isolated product/L E. coli bioreactor culture, thus demonstrating how integrated process design promotes the practical use of a GT conversion. Biotechnol. Bioeng. 2017;114: 924-928. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The complete mitochondrial genome of Gossypium hirsutum and evolutionary analysis of higher plant mitochondrial genomes.

Science.gov (United States)

Liu, Guozheng; Cao, Dandan; Li, Shuangshuang; Su, Aiguo; Geng, Jianing; Grover, Corrinne E; Hu, Songnian; Hua, Jinping

2013-01-01

Mitochondria are the main manufacturers of cellular ATP in eukaryotes. The plant mitochondrial genome contains large number of foreign DNA and repeated sequences undergone frequently intramolecular recombination. Upland Cotton (Gossypium hirsutum L.) is one of the main natural fiber crops and also an important oil-producing plant in the world. Sequencing of the cotton mitochondrial (mt) genome could be helpful for the evolution research of plant mt genomes. We utilized 454 technology for sequencing and combined with Fosmid library of the Gossypium hirsutum mt genome screening and positive clones sequencing and conducted a series of evolutionary analysis on Cycas taitungensis and 24 angiosperms mt genomes. After data assembling and contigs joining, the complete mitochondrial genome sequence of G. hirsutum was obtained. The completed G.hirsutum mt genome is 621,884 bp in length, and contained 68 genes, including 35 protein genes, four rRNA genes and 29 tRNA genes. Five gene clusters are found conserved in all plant mt genomes; one and four clusters are specifically conserved in monocots and dicots, respectively. Homologous sequences are distributed along the plant mt genomes and species closely related share the most homologous sequences. For species that have both mt and chloroplast genome sequences available, we checked the location of cp-like migration and found several fragments closely linked with mitochondrial genes. The G. hirsutum mt genome possesses most of the common characters of higher plant mt genomes. The existence of syntenic gene clusters, as well as the conservation of some intergenic sequences and genic content among the plant mt genomes suggest that evolution of mt genomes is consistent with plant taxonomy but independent among different species.

Risks of increased UV-B radiation: higher plants

International Nuclear Information System (INIS)

Rau, W.; Hofmann, H.

1994-01-01

The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

Concepts, strategies and potentials using hypo-g and other features of the space environment for commercialization using higher plants

Science.gov (United States)

Krikorian, A. D.

1985-01-01

Opportunities for releasing, capturing, constructing and/or fixing the differential expressions or response potentials of the higher plant genome in the hypo-g environment for commercialization are explored. General strategies include improved plant-growing, crop and forestry production systems which conserve soil, water, labor and energy resources, and nutritional partitioning and mobilization of nutrients and synthates. Tissue and cell culture techniques of commercial potential include the growing and manipulation of cultured plant cells in vitro in a bioreactor to produce biologicals and secondary plants of economic value. The facilitation of plant breeding, the cloning of specific pathogen-free materials, the elimination of growing point or apex viruses, and the increase of plant yield are other O-g applications. The space environment may be advantageous in somatic embryogenesis, the culture of alkaloids, and the development of completely new crop plant germ plasm.

Radiation hormesis in higher plants

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Sung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-03-01

The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 times ambient or 100 times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature`s resources demands support to explore the practical application of radiation hormesis.

Radiation hormesis in higher plants

International Nuclear Information System (INIS)

Kim, Jae Sung

1996-03-01

The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 (10 to 1,000) times ambient or 100 (10 to 1,000) times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature's resources demands support to explore the practical application of

Cesium-137 accumulation in higher plants before and after Chernobyl

International Nuclear Information System (INIS)

Sawidis, T.; Drossos, E.; Papastefanou, C.; Heinrick, G.

1990-01-01

Cesium-137 concentrations in plant species of three biotypes of northern Greece, differing in location as well as in vegetation, are reported following the Chernobyl reactor accident. The cesium uptake by plants was due to the foliar deposition rather than the root uptake. The highest level of cesium in plants was found in Ranunculus sardous, a pubescent plant. The 137 Cs concentration was about 22kBq kg -1 d.w. A high level of cesium was also found in Salix alba ( 137 Cs: 19.6 kBq kg -1 d.w.), a deciduous tree showing that hairy leaves or leaves having rough and large surfaces can absorb greater amounts of radioactivity (surface effect). A comparison is also made between the results of measurements of the present study and the results of measurements of some herbarium plants collected one year before the accident as well as the results of measurements of some new plants grown and collected one year after the accident resulting in a natural removal rate of 137 Cs in plants varying from 14 to 130 days

Extraction of Crude Chitinase from Higher Plants and their Chitin-Hydrolysis Activities; Kotosyokubutu yurai kichinaze no chusyutu to kichin bunkai kassei

Energy Technology Data Exchange (ETDEWEB)

Kondo, K.; Harada, K.; Shibata, M.; Maeda, R. [Doshisha Univ., Kyoto (Japan). Faculty of Engineering

1997-07-10

To prepare a purified chitinase from higher plants, firstly, crude enzymes were extracted from six higher plants, namely, radish seeds, sunflower seeds, watermelon seeds, bamboo leaves, orange skin, and persimmon skin. Using these crude enzymes, pH dependencies of hydrolysis reaction of colloidal chitin are investigated. For radish seeds and bamboo leaves, which have relatively high activities, the kinetics of enzymatic reaction are studies. It is clear that these reactions obey Michaelis-Menten kinetics. 7 refs., 3 figs., 2 tabs.

African Journal of Biotechnology - Vol 10, No 32 (2011)

African Journals Online (AJOL)

Seed germination and in vitro regeneration of the African medicinal and pesticidal plant, Bobgunnia madagascariensis · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT ... An alkaliphilic cyclodextrin glycosyltransferase from a new Bacillus agaradhaerens WN-I strain isolated from an Egyptian soda lake: Purification and ...

Reconciling functions and evolution of isoprene emission in higher plants.

Science.gov (United States)

Loreto, Francesco; Fineschi, Silvia

2015-04-01

Compilation and analysis of existing inventories reveal that isoprene is emitted by c. 20% of the perennial vegetation of tropical and temperate regions of the world. Isoprene emitters are found across different plant families without any clear phylogenetic thread. However, by critically appraising information in inventories, several ecological patterns of isoprene emission can be highlighted, including absence of emission from C4 and annual plants, and widespread emission from perennial and deciduous plants of temperate environments. Based on this analysis, and on available information on biochemistry, ecology and functional roles of isoprene, it is suggested that isoprene may not have evolved to help plants face heavy or prolonged stresses, but rather assists C3 plants to run efficient photosynthesis and to overcome transient and mild stresses, especially during periods of active plant growth in warm seasons. When the stress status persists, or when evergreen leaves cope with multiple and repeated stresses, isoprene biosynthesis is replaced by the synthesis of less volatile secondary compounds, in part produced by the same biochemical pathway, thus indicating causal determinism in the evolution of isoprene-emitting plants in response to the environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

[A novel M142T mutation in the B glycosyltransferase gene associated with B3 variant in Chinese].

Science.gov (United States)

Xu, Xian-guo; Hong, Xiao-zhen; Liu, Ying; Zhu, Fa-ming; Lv, Hang-jun; Yan, Li-xing

2009-06-01

To investigate the molecular genetic basis of the B3 variant of ABO blood group system with mixed-field hemagglutination in Chinese. Serological techniques were performed to characterize the erythrocyte phenotype of two discrepant samples. A sequential agglutination method and 13 short tandem repeat (STR) loci were tested to exclude the possibility of exogenous or endogenous DNA chimera. Mutations in exons 6 and 7, including partial intron of the ABO gene, were screened by polymerase chain reaction and DNA sequencing. Haplotypes of the two individuals were also analyzed by sequencing. A mixed-field hemagglutination of RBCs with anti-B and anti-AB antibodies was detected in the two unrelated individuals. Exogenous ABO-incompatible RBC transfusion and endogenous genetic chimera were excluded by sequential agglutination method and STR. The ABO phenotypes of the two individuals were classified as A1B3 according to the ABO subgroup definition. The sequence region from intron 5 to 3'-UTR of the B allele was identical to that of ABO*B101 allele, except for a T to C substitution at nucleotide position 425 in exon 7. This substitution resulted in an amino acid change of M142T in the B glycosyltransferase. A novel B allele with 425T>C substitution resulting in B3 subgroup was identified in two Chinese individuals.

The molecular basis of disease resistance in higher plants

African Journals Online (AJOL)

xxxxxx

Therefore, manipulating a single transcription factor could have the same effect as manipulating a set of specific genes within the plant. As highlighted above, transgenic plants allow the targeted ... including molecular techniques and genetics will provide insights into pathogen-defense mechanism and subsequent disease ...

Scaling down the size and increasing the throughput of glycosyltransferase assays: activity changes on stem cell differentiation.

Science.gov (United States)

Patil, Shilpa A; Chandrasekaran, E V; Matta, Khushi L; Parikh, Abhirath; Tzanakakis, Emmanuel S; Neelamegham, Sriram

2012-06-15

Glycosyltransferases (glycoTs) catalyze the transfer of monosaccharides from nucleotide-sugars to carbohydrate-, lipid-, and protein-based acceptors. We examined strategies to scale down and increase the throughput of glycoT enzymatic assays because traditional methods require large reaction volumes and complex chromatography. Approaches tested used (i) microarray pin printing, an appropriate method when glycoT activity was high; (ii) microwells and microcentrifuge tubes, a suitable method for studies with cell lysates when enzyme activity was moderate; and (iii) C(18) pipette tips and solvent extraction, a method that enriched reaction product when the extent of reaction was low. In all cases, reverse-phase thin layer chromatography (RP-TLC) coupled with phosphorimaging quantified the reaction rate. Studies with mouse embryonic stem cells (mESCs) demonstrated an increase in overall β(1,3)galactosyltransferase and α(2,3)sialyltransferase activity and a decrease in α(1,3)fucosyltransferases when these cells differentiate toward cardiomyocytes. Enzymatic and lectin binding data suggest a transition from Lewis(x)-type structures in mESCs to sialylated Galβ1,3GalNAc-type glycans on differentiation, with more prominent changes in enzyme activity occurring at later stages when embryoid bodies differentiated toward cardiomyocytes. Overall, simple, rapid, quantitative, and scalable glycoT activity analysis methods are presented. These use a range of natural and synthetic acceptors for the analysis of complex biological specimens that have limited availability. Copyright © 2012 Elsevier Inc. All rights reserved.

Hygiene evaluation of the air conditions in the Lower Main region by means of higher and lower plants

Energy Technology Data Exchange (ETDEWEB)

Steubing, L; Klee, R; Kirschbaum, U

1974-06-01

By using the distribution patterns of natural growths of epiphytic lichens, three lichen zones can be distinguished in the Lower Main region of FRG. Each zone corresponds to different degrees of injury to lichens, and each zone is characterized by a particular pollutant load. Damage to plants is functionally correlated with the destruction of chlorophyll. Primary production, dust covering, sulfur content and conductivity of higher plants in two of the lichen zones confirm the data from test stations.

Higher plants as biomonitors of radionuclides in urban air

International Nuclear Information System (INIS)

Ajtic, J.; Todorovic, D.; Popovic, D.; Nikolic, J.

2011-01-01

Two deciduous tree genera, linden (Tilia tomentosa L. and Tilia cordata Mill.) and chestnut (Aesculus hippocastanum L.), are analysed as biomonitors of 210 Pb and 7 Be in air. In a multi year study (2002 - 2009), conducted in three city parks in Belgrade, the content of 210 Pb and 7 Be in samples of leaves of linden and chestnut trees, and aerosols was determined on an HPGe detector by standard gamma spectrometry. The differences seen in the radionuclides' activities across the measurement sites and between the tree genera are not significant, suggesting that the micro climate, level of air pollution and physiological characteristics of the trees have a negligible effect on the radionuclides' activities in leaves. Linear Pearson's correlation coefficients are used to correlate the 210 Pb and 7 Be activities in aerosols and in leaves. The results show that linden could be used as a 210 Pb biomonitor which provides information on the recent history of exposure. No large positive correlation is found for the 7 Be activities in leaves and aerosols, indicating that higher plants are not a suitable biomonitor for this radionuclide. [sr

Site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance substrate specificity towards maltodextrin for enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G).

Science.gov (United States)

Han, Ruizhi; Liu, Long; Shin, Hyun-dong; Chen, Rachel R; Du, Guocheng; Chen, Jian

2013-07-01

In this work, the site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase towards maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) by CGTase. When using maltodextrin as glycosyl donor, four mutants K47F (lysine→ phenylalanine), K47L (lysine→ leucine), K47V (lysine→ valine) and K47W (lysine→ tryptophan) showed higher AA-2G yield as compared with that produced by the wild-type CGTase. The transformation conditions (temperature, pH and the mass ratio of L-ascorbic acid to maltodextrin) were optimized and the highest titer of AA-2G produced by the mutant K47L could reach 1.97 g/l, which was 64.2% higher than that (1.20 g/l) produced by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, the four mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. The mechanism responsible for the enhanced substrate specificity was further explored by structure modeling and it was indicated that the enhancement of maltodextrin specificity may be due to the short residue chain and the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. Here the obtained mutant CGTases, especially the K47L, has a great potential in the production of AA-2G with maltodextrin as a cheap and easily soluble substrate.

Expression and Purification of Glycosyltransferases in Pichia Pastoris: Towards Improving the Migration of Stem Cells by Enhancing Surface Expression of Sialyl Lewis X

KAUST Repository

Al-Amoodi, Asma S.

2017-05-01

Recruitment of circulating cells towards target sites is primarily dependent on E-selectin receptor/ligand adhesive interactions. Glycosyltransferase (GTs) are involved in the creation of E-selectin ligands. A sialofucosylated terminal tetrasaccharide like glycan structure known as sialyl Lewis x (sLex), is the most recognized ligand by selectins. This structure is found on the surface of cancer cells and leukocytes but is often absent on the surface of many adult stem cell populations. In order to synthesize sLex, GTs must be endogenously expressed and remain active within the cells. Generally, these stem cells express terminal sialylated lactosamine structures on their glycoproteins which require the addition of alpha-(1,3)-fucose to be converted into an E-selectin ligand. There are a number of fucosyltransferases (FUTs) that are able to modify terminal lactosamine structures to create sLex such as FUT6. In this work we focused on expressing and purifying active recombinant FUTs as a tool to help create sLex structures on the surface of adult stem cells in order to enhance their migration.

CEZ utility's coal-fired power plants: towards a higher environmental friendliness

International Nuclear Information System (INIS)

Kindl, V.; Spilkova, T.; Vanousek, I.; Stehlik, J.

1996-01-01

Environmental efforts of the major Czech utility, CEZ a.s., are aimed at reducing air pollution arising from electricity and heat generating facilities. There are 3 main kinds of activity in this respect: phasing out of coal fired power plants; technological provisions to reduce emissions of particulate matter, sulfur dioxide, and nitrogen oxides from those coal fired units that are to remain in operation after 1998; and completion of the Temelin nuclear power plant. In 1995, emissions of particulate matter, sulfur dioxide, nitrogen oxides, and carbon monoxide from CEZ's coal fired power plants were 19%, 79%, 59%, and 60%, respectively, with respect to the situation in 1992. The break-down of electricity generation by CEZ facilities (in GWh) was as follows in 1995: hydroelectric power plants 1673, nuclear power plants 12230, coal fired power plants without desulfurization equipment 30181, and coal fired power plants with desulfurization equipment 2277. Provisions implemented to improve the environmental friendliness of the individual CEZ's coal fired power plants are described in detail. (P.A.). 5 tabs., 1 fig

Structure and Mechanism of Staphylococcus aureus TarS, the Wall Teichoic Acid β-glycosyltransferase Involved in Methicillin Resistance.

Directory of Open Access Journals (Sweden)

Solmaz Sobhanifar

2016-12-01

Full Text Available In recent years, there has been a growing interest in teichoic acids as targets for antibiotic drug design against major clinical pathogens such as Staphylococcus aureus, reflecting the disquieting increase in antibiotic resistance and the historical success of bacterial cell wall components as drug targets. It is now becoming clear that β-O-GlcNAcylation of S. aureus wall teichoic acids plays a major role in both pathogenicity and antibiotic resistance. Here we present the first structure of S. aureus TarS, the enzyme responsible for polyribitol phosphate β-O-GlcNAcylation. Using a divide and conquer strategy, we obtained crystal structures of various TarS constructs, mapping high resolution overlapping N-terminal and C-terminal structures onto a lower resolution full-length structure that resulted in a high resolution view of the entire enzyme. Using the N-terminal structure that encapsulates the catalytic domain, we furthermore captured several snapshots of TarS, including the native structure, the UDP-GlcNAc donor complex, and the UDP product complex. These structures along with structure-guided mutants allowed us to elucidate various catalytic features and identify key active site residues and catalytic loop rearrangements that provide a valuable platform for anti-MRSA drug design. We furthermore observed for the first time the presence of a trimerization domain composed of stacked carbohydrate binding modules, commonly observed in starch active enzymes, but adapted here for a poly sugar-phosphate glycosyltransferase.

Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge.

Science.gov (United States)

Nol, Pauline; Olsen, Steven C; Rhyan, Jack C; Sriranganathan, Nammalwar; McCollum, Matthew P; Hennager, Steven G; Pavuk, Alana A; Sprino, Phillip J; Boyle, Stephen M; Berrier, Randall J; Salman, Mo D

2016-01-01

In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk.

Electric current precedes emergence of a lateral root in higher plants.

Science.gov (United States)

Hamada, S; Ezaki, S; Hayashi, K; Toko, K; Yamafuji, K

1992-10-01

Stable electrochemical patterns appear spontaneously around roots of higher plants and are closely related to growth. An electric potential pattern accompanied by lateral root emergence was measured along the surface of the primary root of adzuki bean (Phaseolus angularis) over 21 h using a microelectrode manipulated by a newly developed apparatus. The electric potential became lower at the point where a lateral root emerged. This change preceded the emergence of the lateral root by about 10 h. A theory is presented for calculating two-dimensional patterns of electric potential and electric current density around the primary root (and a lateral root) using only data on the one-dimensional electric potential measured near the surface of the primary root. The development of the lateral root inside the primary root is associated with the influx of electric current of about 0.7 muA.cm(-2) at the surface.

Interference of Cd2+ in functioning of the photosynthetic apparatus of higher plants

Directory of Open Access Journals (Sweden)

Tadeusz Baszyński

2014-01-01

Full Text Available The actual opinions concerning the role of Cd2+ in inhibition of photosynthesis have been reviewed. The light phase of photosynthesis, particularly the site of Cd2+ action in the photosynthetic transport chain has been given the greatest attention. Cd2+-induced inhibition of Photosystem II activity as the result of thylakoid membrane degradation has been discussed. The present studies on Cd2+-inhibited dark reactions occurring in stroma has been analysed. Attention has been drawn to the fact that the results of studies in vitro are not always compatible with the changes found in the photosynthetic apparatus of higher plants growing in a Cd2 containing medium.

Plant design aspects of catalytic biosyngas conversion to higher alcohols

International Nuclear Information System (INIS)

Atsonios, K.; Christodoulou, Ch.; Koytsoumpa, E.-I.; Panopoulos, K.D.; Kakaras, Em.

2013-01-01

Although biomethanol production has attracted most of the attention in the past years, there is a current trend for the synthesis of higher alcohols (i.e. ethanol, plus C 3 –C 4 ) from biomass gasification. These compounds could be used directly as fuel or fuel additives for octane or cetane number enhancement. These also serve as important intermediates for the chemical industry. In this paper a comparison is performed between the different process configurations a higher alcohols production plant from biomass gasification can take. These options are modelled in Aspenplus™; all steps and important unit operations are presented with the aim to correctly evaluate the peripheral energy requirements and conclude with the overall thermodynamic limitations of the processes. The differentiation between black liquor and solid biomass gasification, the type of catalyst employed, and the effect of the recycling scheme adopted for the reutilization of unreacted syngas are evaluated. The design has to cope with the limited yields and poor selectivity of catalysts developed so far. The gas cleaning is different depending on the different requirements of the catalysts as far as H 2 S purity. The process modelling results reveal that the hydrogenation of CO to higher alcohols is favoured by high pressure, temperature around 325 °C and high reactor residence times. A biorefinery using modified Fisher–Tropsch (FT) catalysts (MoS 2 ) prevail over modified MeOH catalyst (Cu–Zn based) for HA production. The efficiency of HA production in HHV terms can reach up to 25%. -- Graphical abstract: Process flow diagrams of different biorefinery systems derived from a) woody biomass and b) black liquor. Highlights: ► An integrated gasification/gas-cleaning/synthesis system was modelled in Aspenplus. ► HA production from wood and black liquor gasification is compared. ► Modified FT catalysts prevail over modified methanol catalyst for HA production. ► HA productivity is

Effects of fluoride on mitochondrial activity in higher plants. [Glycine max, Zea mays

Energy Technology Data Exchange (ETDEWEB)

Miller, J E; Miller, G W

1974-01-01

The effects of fluoride on respiration of plant tissue and mitochondria were investigated. Fumigation of young soybean plants (Glycine max Merr. cm. Hawkeye) with 9-12 ..mu..g x m/sup -3/ HF caused a stimulation of respiration at about 2 days of treatment followed by inhibition 2 days later. Mitochondria isolated from the stimulated tissue had higher respiration rates, greater ATPase activity, and lower P/O ratios, while in mitochondria from inhibited tissue, all three were reduced. Treatment of etiolated soybean hypocotyl sections in Hoagland's solution containing KF for 3 to 10 h only resulted in inhibition of respiration. Mitochondria isolated from this tissue elicited increased respiration rates with malate as substrate and inhibited respiration with succinate. With both substrates respiratory control and ADP/O ratios were decreased. Direct treatment of mitochondria from etiolated soybean hypocotyl tissue with fluoride resulted in inhibition of state 3 respiration and lower ADP/O ratios with the substrates succinate, malate, and NADH. Fluoride was also found to increase the amount of osmotically induced swelling and cause a more rapid leakage of protein with mitochondria isolated from etiolated corn shoots (Zea mays L. cv. Golden Cross Bantam). 40 references, 1 figure, 5 tables.

Consequences of variation in plant defense for biodiversity at higher trophic levels

NARCIS (Netherlands)

Poelman, E.H.; Loon, van J.J.A.; Dicke, M.

2008-01-01

Antagonistic interactions between insect herbivores and plants impose selection on plants to defend themselves against these attackers. Although selection on plant defense traits has typically been studied for pairwise plant¿attacker interactions, other community members of plant-based food webs are

Biochemical studies on the effect of fluoride on higher plants. II. The effect of fluoride on sucrose-synthesizing enzymes from higher plants

Energy Technology Data Exchange (ETDEWEB)

Yang, S F; Miller, G W

1963-01-01

A study was initiated to characterize the properties of partially purified phosphoglucomutase, uridine diphosphate glucose pyrophosphorylase and uridine diphosphate glucose-fructose transglucosyalse, from various plant sources, with respect to activation by metal ions and inhibition by fluoride. Of the three enzymes studied, only phosphoglucomutase was very sensitive to fluoride. It is likely that the inhibition of sucrose synthesis in fluoride-fumigated plants might be due to the inhibition of phosphoglucomutase, which plays an important role in carbohydrate metabolism. However, at present, there is insufficient evidence to show the inhibition of phosphoglucomutase in vivo by fumigation with hydrogen fluoride.

Effects of long-term radiation exposure on the higher aquatic plants in the Chernobyl exclusion zone

Energy Technology Data Exchange (ETDEWEB)

Shevtsova, N.; Gudkov, D. [Institute of Hydrobiology (Russian Federation)

2014-07-01

germinated seeds) and pinnacle deviations was registered in plants from the most radioactive contaminated water bodies. Also the decreasing of parasitic stability of one of aquatic plant communities' dominant species - the common reed is observed. The data of the mite Steneotarsonemus phragmitidis and the parasitic fungus Claviceps purpurea hitting of the common reed, correlated with radiation dose rate. It was determined the positive correlation between absorbed dose rate and chromosome aberration rate in roots of the twelve aquatic plants' species from sampling water bodies. The highest rate of chromosome aberrations (up to 17 %) were registered in plants with high level of morphological deviations in seeds germs, but not panicles. The data obtained from the complex analysis of natural aquatic plant communities from the radioactive contaminated water bodies testify about rather high level of genetic efficiency of low doses of long-term exposure. For higher aquatic plants from ChEZ there is observed a realization of radiobiological reactions on morphological and reproductive levels on the background of genetic instability induced by low doses. Document available in abstract form only. (authors)

Reduction of starch granule size by expression of an engineered tandem starch-binding domain in potato plants

NARCIS (Netherlands)

Ji, Q.; Oomen, R.J.F.J.; Vincken, J.P.; Bolam, D.N.; Gilbert, H.J.; Suurs, L.C.J.M.; Visser, R.G.F.

2004-01-01

Granule size is an important parameter when using starch in industrial applications. An artificial tandem repeat of a family 20 starch-binding domain (SBD2) was engineered by two copies of the SBD derived from Bacillus circulans cyclodextrin glycosyltransferase via the Pro-Thr-rich linker peptice

Over-expression of UDP-glycosyltransferase gene UGT2B17 is involved in chlorantraniliprole resistance in Plutella xylostella (L.).

Science.gov (United States)

Li, Xiuxia; Zhu, Bin; Gao, Xiwu; Liang, Pei

2017-07-01

UDP-glycosyltransferases (UGTs) are phase II detoxification enzymes widely distributed within living organisms. Their involvement in the biotransformation of various lipophilic endogenous compounds and phytoalexins in insects has been documented. However, the roles of this enzyme family in insecticide resistance have rarely been reported. Here, the functions of UGTs in chlorantraniliprole resistance in Plutella xylostella were investigated. Treatment with sulfinpyrazone and 5-nitrouracil (both inhibitors of UGT enzymes) significantly increased the toxicity of chlorantraniliprole against the third instar larvae of P. xylostella. Among the 23 UGT transcripts examined, only UGT2B17 was found to be over-expressed (with a range from 30.7- to 77.3-fold) in all four chlorantraniliprole-resistant populations compared to the susceptible one (CHS). The knock-down of UGT2B17 by RNA interference (RNAi) dramatically increased the toxicity of chlorantraniliprole by 27.4% and 29.8% in the CHS and CHR (resistant) populations, respectively. In contrast, exposure to phenobarbital significantly increased the relative expression of UGT2B17 while decreasing the toxicity of chlorantraniliprole to the larvae by 14.0%. UGT2B17 is involved in the detoxification of chlorantraniliprole, and its over-expression may play an important role in chlorantraniliprole resistance in P. xylostella. These results shed some light upon and further our understanding of the mechanisms of diamide insecticide resistance in insects. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Production characteristics of lettuce Lactuca sativa L. in the frame of the first crop tests in the Higher Plant Chamber integrated into the MELiSSA Pilot Plant

Science.gov (United States)

Tikhomirova, Natalia; Lawson, Jamie; Stasiak, Michael; Dixon, Mike; Paille, Christel; Peiro, Enrique; Fossen, Arnaud; Godia, Francesc

Micro-Ecological Life Support System Alternative (MELiSSA) is an artificial closed ecosystem that is considered a tool for the development of a bioregenerative life support system for manned space missions. One of the five compartments of MELiSSA loop -Higher Plant Chamber was recently integrated into the MELiSSA Pilot Plant facility at Universitat Aut`noma deo Barcelona. The main contributions expected by integration of this photosynthetic compartment are oxygen, water, vegetable food production and CO2 consumption. Production characteristics of Lactuca sativa L., as a MELiSSA candidate crop, were investigated in this work in the first crop experiments in the MELiSSA Pilot Plant facility. The plants were grown in batch culture and totaled 100 plants with a growing area 5 m long and 1 m wide in a sealed controlled environment. Several replicates of the experiments were carried out with varying duration. It was shown that after 46 days of lettuce cultivation dry edible biomass averaged 27, 2 g per plant. However accumulation of oxygen in the chamber, which required purging of the chamber, and decrease in the food value of the plants was observed. Reducing the duration of the tests allowed uninterrupted test without opening the system and also allowed estimation of the crop's carbon balance. Results of productivity, tissue composition, nutrient uptake and canopy photosynthesis of lettuce regardless of test duration are discussed in the paper.

Purification and characterisation of Cyclodextrin glycosyltransferase ...

African Journals Online (AJOL)

EXPER

2012-06-05

Jun 5, 2012 ... require higher temperatures for the liquefaction of starch at which CGTases ... growth medium by centrifugation at 12000 x g for 15 min. Cell-free supernatant ..... 95°C, thermal inactivation was only 13% (Figure 3). Enzyme ...

Conserved upstream open reading frames in higher plants

Directory of Open Access Journals (Sweden)

Schultz Carolyn J

2008-07-01

Full Text Available Abstract Background Upstream open reading frames (uORFs can down-regulate the translation of the main open reading frame (mORF through two broad mechanisms: ribosomal stalling and reducing reinitiation efficiency. In distantly related plants, such as rice and Arabidopsis, it has been found that conserved uORFs are rare in these transcriptomes with approximately 100 loci. It is unclear how prevalent conserved uORFs are in closely related plants. Results We used a homology-based approach to identify conserved uORFs in five cereals (monocots that could potentially regulate translation. Our approach used a modified reciprocal best hit method to identify putative orthologous sequences that were then analysed by a comparative R-nomics program called uORFSCAN to find conserved uORFs. Conclusion This research identified new genes that may be controlled at the level of translation by conserved uORFs. We report that conserved uORFs are rare (

Structure of the higher plant light harvesting complex I: in vivo characterization and structural interdependence of the Lhca proteins.

Science.gov (United States)

Klimmek, Frank; Ganeteg, Ulrika; Ihalainen, Janne A; van Roon, Henny; Jensen, Poul E; Scheller, Henrik V; Dekker, Jan P; Jansson, Stefan

2005-03-01

We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding that there are four Lhca proteins per PSI in the crystal structure [Ben-Shem, A., Frolow, F., and Nelson, N. (2003) Nature 426, 630-635]. According to HPLC analyses the number of pigment molecules bound within the LHCI is higher than expected from reconstitution studies or analyses of isolated native LHCI. Comparison of the spectra of the particles from the different lines reveals chlorophyll absorption bands peaking at 696, 688, 665, and 655 nm that are not present in isolated PSI or LHCI. These bands presumably originate from "gap" or "linker" pigments that are cooperatively coordinated by the Lhca and/or PSI proteins, which we have tentatively localized in the PSI-LHCI complex.

Investigation of the non-photochemical processes in photosynthetic bacteria and higher plants using interference of coherent radiation - a new approach

Czech Academy of Sciences Publication Activity Database

Roháček, Karel; Kloz, M.; Bína, David; Batysta, F.; Vácha, František

2007-01-01

Roč. 91, 2-3 (2007), s. 301 ISSN 0166-8595. [International Congress of Photosynthesis/14./. 22.07.2007-27.07.2007, Glasgow] Institutional research plan: CEZ:AV0Z50510513 Keywords : Photosynthesis * higher plants Subject RIV: CE - Biochemistry

Results of the first stage (2002-2009) of investigation of higher plants onboard RS ISS, as an element of future closed Life Support Systems

Science.gov (United States)

Sychev, Vladimir; Levinskikh, Margarita; Podolsky, Igor; Bingham, Gail; Novikova, Nataliya; Sugimoto, Manabu

A key task for biomedical human support in long-term manned space expeditions is the develop-ment of the Life Support System (LSS). It is expected that in the first continuous interplanetary expeditions LSS of only a few biological elements of the LSS, such as higher plants will be in-cluded. Therefore, investigations of growth and development of higher plants for consideration in the LSS are of high importance. In a period from October, 2002 to December 2009, 15 ex-periments on cultivation of different plants, including two genetically marked species of dwarf peas, a leaf vegetable strain of Mizuna, radish, barley and wheat were conducted in space greenhouse "LADA" onboard Russian Segment (RS) of International Space Station (ISS). The experiments resulted in the conclusion that the properties of growth and development of plants grown in space greenhouse "LADA" were unaffected by spaceflight conditions. In experiments conducted in a period from 2003 to 2005, it was shown for the first time that pea plants pre-serve reproductive functions, forming viable seeds during at least four continuous full cycles of ontogenesis ("seed to seed") under spaceflight conditions. No changes were found in the genetic apparatus of the pea plants in the four "space" generations. Since 2005, there have been routine collections of microbiological samples from the surfaces of the plants grown on-board in "LADA" greenhouse. Analysis has shown that the properties of contamination of the plants grown aboard by microorganism contain no abnormal patterns. Since 2008, the plants cultivated in "LADA" greenhouse have been frozen onboard RS ISS in the MELFI refrigerator and transferred to the Earth for further investigations. Investigations of Mizuna plants grown and frozen onboard of ISS, showed no differences between "ground control" and "space" plants in chemical and biochemical properties. There also no stress-response was found in kashinriki strain barley planted and frozen onboard ISS.

A Studi on High Plant Systems Course with Active Learning in Higher Education Through Outdoor Learning to Increase Student Learning Activities

OpenAIRE

Nur Rokhimah Hanik, Anwari Adi Nugroho

2015-01-01

Biology learning especially high plant system courses needs to be applied to active learning centered on the student (Active Learning In Higher Education) to enhance the students' learning activities so that the quality of learning for the better. Outdoor Learning is one of the active learning invites students to learn outside of the classroom by exploring the surrounding environment. This research aims to improve the students' learning activities in the course of high plant systems through t...

An expanding universe of circadian networks in higher plants.

Science.gov (United States)

Pruneda-Paz, Jose L; Kay, Steve A

2010-05-01

Extensive circadian clock networks regulate almost every biological process in plants. Clock-controlled physiological responses are coupled with daily oscillations in environmental conditions resulting in enhanced fitness and growth vigor. Identification of core clock components and their associated molecular interactions has established the basic network architecture of plant clocks, which consists of multiple interlocked feedback loops. A hierarchical structure of transcriptional feedback overlaid with regulated protein turnover sets the pace of the clock and ultimately drives all clock-controlled processes. Although originally described as linear entities, increasing evidence suggests that many signaling pathways can act as both inputs and outputs within the overall network. Future studies will determine the molecular mechanisms involved in these complex regulatory loops. 2010 Elsevier Ltd. All rights reserved.

Studies on the application of radiation for genetic transformation in higher plants

International Nuclear Information System (INIS)

Lee, Young Il; Song, Hi Sup; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae; Lee, Ki Woon; Lim, Yong Taek

1992-02-01

Present research carried out to develop the radiation application on the mutation research of genetic engineering. Some variants selected in M1 generation derived from the plantlet by the nodal stem culture of three potato cultivars irradiated with gamma rays, and the optimum dosage for mutation induction was revealed the range of 30 - 50 Gy of gamma ray. In the rice anther culture of the plant irradiated with gamma rays at different developmental stage of microspore, the haploidy callus formation rates were much higher in gamma ray irradiated anthers than those of non-irradiated, and the occurrence of a typical pollen was significantly increased up to 47% in the anthers irradiated with 30 Gy of gamma ray compared with 11% of non-irradiated anthers at the stage of pollen mother cell. A lot of variants were selected in rice, soybean, perilla and red pepper irradiated with gamma rays for breeding of earliness, short culm, high yielding and disease resistant mutant. (Author)

Diets higher in animal and plant protein are associated with lower adiposity and do not impair kidney function in US adults.

Science.gov (United States)

Berryman, Claire E; Agarwal, Sanjiv; Lieberman, Harris R; Fulgoni, Victor L; Pasiakos, Stefan M

2016-09-01

Higher-protein diets are associated with decreased adiposity and greater HDL cholesterol than lower protein diets. Whether these benefits can be attributed to a specific protein source (i.e., nondairy animal, dairy, or plant) is unknown, and concerns remain regarding the impact of higher-protein diets on kidney function. The objective of this study was to evaluate trends of protein source on markers of cardiometabolic disease risk and kidney function in US adults. Total, nondairy animal, dairy, and plant protein intake were estimated with the use of 24-h recall data from NHANES 2007-2010 (n = 11,111; ≥19 y). Associations between source-specific protein intake and health outcomes were determined with the use of models that adjusted for sex, race and ethnicity, age, physical activity, poverty-to-income ratio, individual intake (grams per kilogram) for each of the other 2 protein sources, body mass index (BMI) (except for weight-related variables), and macronutrient (carbohydrate, fiber, and total and saturated fat) intake. Mean ± SE total protein intake was 82.3 ± 0.8 g/d (animal: 37.4 ± 0.5 g/d; plant: 24.7 ± 0.3 g/d; and dairy: 13.4 ± 0.3 g/d). Both BMI and waist circumference were inversely associated [regression coefficient (95% CI)] with animal [-0.199 (-0.265, -0.134), P protein intake. Blood urea nitrogen concentrations increased across deciles for animal [0.313 (0.248, 0.379), P protein intake. Glomerular filtration rate and blood creatinine were not associated with intake of any protein source. Diets higher in plant and animal protein, independent of other dietary factors, are associated with cardiometabolic benefits, particularly improved central adiposity, with no apparent impairment of kidney function. © 2016 American Society for Nutrition.

Ab initio calculations of the Fe(II) and Fe(III) isotopic effects in citrates, nicotianamine, and phytosiderophore, and new Fe isotopic measurements in higher plants

Science.gov (United States)

Moynier, Frédéric; Fujii, Toshiyuki; Wang, Kun; Foriel, Julien

2013-05-01

Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ˜3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ˜1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem.

Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

Science.gov (United States)

2013-01-01

Background Fungi produce a variety of carbohydrate activity enzymes (CAZymes) for the degradation of plant polysaccharide materials to facilitate infection and/or gain nutrition. Identifying and comparing CAZymes from fungi with different nutritional modes or infection mechanisms may provide information for better understanding of their life styles and infection models. To date, over hundreds of fungal genomes are publicly available. However, a systematic comparative analysis of fungal CAZymes across the entire fungal kingdom has not been reported. Results In this study, we systemically identified glycoside hydrolases (GHs), polysaccharide lyases (PLs), carbohydrate esterases (CEs), and glycosyltransferases (GTs) as well as carbohydrate-binding modules (CBMs) in the predicted proteomes of 103 representative fungi from Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. Comparative analysis of these CAZymes that play major roles in plant polysaccharide degradation revealed that fungi exhibit tremendous diversity in the number and variety of CAZymes. Among them, some families of GHs and CEs are the most prevalent CAZymes that are distributed in all of the fungi analyzed. Importantly, cellulases of some GH families are present in fungi that are not known to have cellulose-degrading ability. In addition, our results also showed that in general, plant pathogenic fungi have the highest number of CAZymes. Biotrophic fungi tend to have fewer CAZymes than necrotrophic and hemibiotrophic fungi. Pathogens of dicots often contain more pectinases than fungi infecting monocots. Interestingly, besides yeasts, many saprophytic fungi that are highly active in degrading plant biomass contain fewer CAZymes than plant pathogenic fungi. Furthermore, analysis of the gene expression profile of the wheat scab fungus Fusarium graminearum revealed that most of the CAZyme genes related to cell wall degradation were up-regulated during plant infection. Phylogenetic analysis also

Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, Cindy [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Mueller, Uwe [Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung mbH, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany); Panjikar, Santosh [European Molecular Biology Laboratory Hamburg, Outstation Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Sun, Lianli [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China); Ruppert, Martin [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Zhao, Yu [Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China); Stöckigt, Joachim [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China)

2006-12-01

Perakine reductase, a novel member of the aldo-keto reductase enzyme superfamily of higher plants, is involved in the biosynthesis of monoterpenoid indole alkaloids in the Indian medicinal plant Rauvolfia serpentina. The enzyme has been crystallized in C-centered orthorhombic space group and diffracts to 2.0 Å resolution. Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C222{sub 1} and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å.

Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

International Nuclear Information System (INIS)

Rosenthal, Cindy; Mueller, Uwe; Panjikar, Santosh; Sun, Lianli; Ruppert, Martin; Zhao, Yu; Stöckigt, Joachim

2006-01-01

Perakine reductase, a novel member of the aldo-keto reductase enzyme superfamily of higher plants, is involved in the biosynthesis of monoterpenoid indole alkaloids in the Indian medicinal plant Rauvolfia serpentina. The enzyme has been crystallized in C-centered orthorhombic space group and diffracts to 2.0 Å resolution. Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C222 1 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å

Early herbivore alert matters: plant-mediated effects of egg deposition on higher trophic levels benefit plant fitness

NARCIS (Netherlands)

Pashalidou, F.G.; Frago, E.; Griese, E.; Poelman, E.H.; Loon, van J.J.A.; Dicke, M.; Fatouros, N.E.

2015-01-01

Induction of plant defences, specifically in response to herbivore attack, can save costs that would otherwise be needed to maintain defences even in the absence of herbivores. However, plants may suffer considerable damage during the time required to mount these defences against an attacker. This

Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

Energy Technology Data Exchange (ETDEWEB)

McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C.; Zhao, F.J.; Stroud, J.L. [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Zhang, H.; Fozard, S. [Division of Environmental Science, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

2010-10-15

Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED{sub 50}) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. - Mo toxicity thresholds varied widely in different soils and therefore soil properties need to be taken into account in order to assess the risk of Mo exposure.

MOLECULAR-GENETIC BASIS OF HIGHER PLANTS TOLERANCE TO, AND ACCUMULATION OF, CADMIUM

Directory of Open Access Journals (Sweden)

Olga A Kulaeva

2010-09-01

Full Text Available Cadmium (Cd is one of the most wide-ranged and dangerous pollutants for all living organisms, including plants. At present time the intensive studies of mechanisms of Cd accumulation in plant tissues and plant tolerance to its toxic influence are performed. Data about variation of Cd tolerance and accumulation traits in natural populations of hyperaccumulators species as well as important crops were obtained. A series of mutants with changed sensitivity to Cd was obtained. In recent decade several classes of proteins involving in cell responses to Cd ions were revealed. An important role of microRNA in plant adaptation to Cd was recently demonstrated. Studies of molecular-genetic mechanisms of Cd accumulation and plant tolerance to it are theoretical basis for development of phytoremediation technologies of soil contaminated with heavy metals and breeding of crop varieties with decreased Cd accumulation.

The use of sulphite solutions for studying the effects of SO2 on higher plants

International Nuclear Information System (INIS)

Garsed, S.G.

1981-01-01

The effects of sulphite concentration and pH on 14 CO 2 fixation or the uptake of 35 S by needle segments of Pinus sylvestris were studied in factorial experiments. In addition, changes in the chemical composition of the sulphite solutions during the experiment were measured. Uptake of 14 CO 2 was increased and standard errors decreased by incorporating 1.0 to 10 ppm of Tween 80 into the solutions used. Inhibition of 14 CO 2 fixation by sulphite was significantly greater at low pH and high sulphite concentration, with a significant interaction. Uptake of Na 2 35 SO 3 was greater at low pH and was linear with respect to the concentration of Na 2 SO 3 carrier added between 10 -3 and 10 -4 M. In the absence of carrier, recovery of 35 S at the end of the experiment was reduced. Oxidation of the sulphite solutions was rapid at high pH and low concentration, with a significant interaction. It was also accelerated by the presence of plant material. The use of sulphite solutions to predict responses of higher plants to SO 2 is discussed. (author)

Fate of induced mutations in higher plants with special emphasis on sexually reproducing species

International Nuclear Information System (INIS)

Cornu, Andre

1978-01-01

A mutation induced in a plant somatic cell has to overcome quite many difficulties before being isolated and utilized as a marker in a mutated line. If induced in a meristem, three conditions must be fulfilled for the mutation to be transmitted to the subsequent generation: it must be compatible with normal cell multiplication, it must be located in a cell mass that will provide an inflorescence, and it must be in the sporogenetic layer (t2). Under these conditions, or if it is induced in a gamete or in a zygote, the mutation enters a first cycle of sexual reproduction. Meiosis and the subsequent haploid phase constitute severe screening steps for many chromosome aberrations. Studies on Petunia performed by means of marker genes show that male and female gametic viabilities are drastically impaired by deletions. However, a deficient chromosome can be transmitted when the losss of information is compensated for by homologous information as, for example, diploid gametes from tetraploids or disomic gametes resulting from non-disjunction. If partial or complete sterility, whether sporo- or gametophytic, is avoided, then the mutation can be transmitted to the next generation in heterozygous state. When becoming homozygous, the mutation may have effects such that its use can be most difficult. This is the case when this mutation causes rather early lethality or severe sterility. Thus, in higher plants, one faces several cases of powerful and efficient selection against mutations. On the basis of experiments carried out on Petunia, the per locus mutation rate of practical interest ranges between I and 5/10000M 1 plants. Practical conclusions are drawn about which organ should be treated, which mutagen at what dose should be used according to the scope of the research undertaken [fr

Inclusion of human mineralized exometabolites and fish wastes as a source of higher plant mineral nutrition in BTLSS mass exchange

Science.gov (United States)

Tikhomirova, Natalia; Tikhomirov, Alexander A.; Ushakova, Sofya; Anischenko, Olesya; Trifonov, Sergey V.

Human exometabolites inclusion into an intrasystem mass exchange will allow increasing of a closure level of a biological-technical life support system (BTLSS). Previously at the IBP SB RAS it was shown that human mineralized exometabolites could be incorporated in the BTLSS mass exchange as a mineral nutrition source for higher plants. However, it is not known how that combined use of human mineralized exometabolites and fish wastes in the capacity of nutrient medium, being a part of the BTLSS consumer wastes, will affect the plant productivity. Several wheat vegetations were grown in an uneven-aged conveyor on a neutral substrate. A mixture of human mineralized exometabolites and fish wastes was used as a nutrient solution in the experiment treatment and human mineralized exometabolites were used in the control. Consequently, a high wheat yield in the experiment treatment practically equal to the control yield was obtained. Thus, mineralized fish wastes can be an additional source of macro-and micronutrients for plants, and use of such wastes for the plant mineral nutrition allows increasing of BTLSS closure level.

CBL-CIPK network for calcium signaling in higher plants

Science.gov (United States)

Luan, Sheng

Plants sense their environment by signaling mechanisms involving calcium. Calcium signals are encoded by a complex set of parameters and decoded by a large number of proteins including the more recently discovered CBL-CIPK network. The calcium-binding CBL proteins specifi-cally interact with a family of protein kinases CIPKs and regulate the activity and subcellular localization of these kinases, leading to the modification of kinase substrates. This represents a paradigm shift as compared to a calcium signaling mechanism from yeast and animals. One example of CBL-CIPK signaling pathways is the low-potassium response of Arabidopsis roots. When grown in low-K medium, plants develop stronger K-uptake capacity adapting to the low-K condition. Recent studies show that the increased K-uptake is caused by activation of a specific K-channel by the CBL-CIPK network. A working model for this regulatory pathway will be discussed in the context of calcium coding and decoding processes.

The light-harvesting complexes of higher plant Photosystem I: Lhca1/4 and Lhca2/3 form two red-emitting heterodimers

NARCIS (Netherlands)

Wientjes, I.E.; Croce, R.

2011-01-01

The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) a1-Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge

The light-harvesting complexes of higher-plant Photosystem I : Lhca1/4 and Lhca2/3 form two red-emitting heterodimers

NARCIS (Netherlands)

Wientjes, Emilie; Croce, Roberta

2011-01-01

The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) al-Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge

Mechanism of radiation tolerance in higher plants. Radiation damage of DNA in cultured tobacco BY-2 cells and implication from its repair process

International Nuclear Information System (INIS)

Yokota, Yuichiro; Narumi, Issay; Funayama, Tomoo; Kobayashi, Yasuhiko; Tanaka, Jun; Inoue, Masayoshi

2007-01-01

This paper describes the mechanism of radiation tolerance at the cellular level in higher plants, of which fundamental study basis is rather poor, in cultured cells in the title (BY-2 cells, Nicotiana tabacum L., allotetraploid). When compared with LD 50 of radiation in higher animals (2.4-8.6 Gy), higher plants are generally tolerant to radiation (known LD 50 , >360-2000 Gy). Authors have made unicellular BY-2 cells (protoplasts) by enzyme treatment to see their colony forming ability (CFA) and have found those cells are also resistant to radiation: D 10 (10% CFA dose) (Gy) is found to be 8.2-47.2 by radiation with various linear energy transfer (LET)s like gamma ray and heavy ion beams, in contrast to human D 10 (1.17-8.12, by X-ray and carbon beam). Double strand break (DSB) of DNA by radiation per one BY-2 cell initially occurs 7-10 times more frequently than mammalian cells (CHO-K1). However, DSB repair in BY-2 cells is found only as efficient as in mammalian cells: a slow repair relative to DSB number. Checkpoint mechanism of DNA damage is found poorly working in BY-cells, which results in frequent chromosome aberration like micronucleus. Authors consider that, for an herbaceous plant, to precede the cell cycle rather than to recover from the genomic instability can be profitable for growing more rapidly to have more sunlight energy than other individuals. Improvement of plants by gene technological approach with such a mean as mutation by radiation is conceivably important from aspects of food supply and of ecological environment. (R.T.)

Integration of pharmaceuticals with higher plants as a model of phytoremediation

OpenAIRE

Pomeislová, Alice

2015-01-01

The presence of pharmaceuticals in wastewater, which are not eliminated in sewage treatment plant process and thus get easily into rivers and aquatic environment in general, constitutes a severe problem to the whole society. The research into the removal of pharmaceuticals from the environment began about twenty years ago. Phytoremediation represents one of the most promising wastewater treatment methods. It is based on the ability of plants to remove xenobiotics from their environment and se...

Mechanistic studies of ethylene biosynthesis in higher plants

International Nuclear Information System (INIS)

McGeehan, G.M.

1986-01-01

Ethylene is a plant hormone that elicits a wide variety of responses in plant tissue. Among these responses are the hastening of abscission, ripening and senescence. In 1979 it was discovered that 1-amino-1-cyclopropane carboxylic acid is the immediate biosynthetic precursor to ethylene. Given the obvious economic significance of ethylene production the authors concentrated their studies on the conversion of ACC to ethylene. They delved into mechanistic aspects of ACC oxidation and they studied potential inhibitors of ethylene forming enzyme (EFE). They synthesized various analogs of ACC and found that EFE shows good stereodiscrimination among alkyl substituted ACC analogs with the 1R, 2S stereoisomer being processed nine times faster than the 1S, 2R isomer in the MeACC series. They also synthesized 2-cyclopropyl ACC which is a good competitive inhibitor of EFE. This compound also causes time dependent loss of EFE activity leading us to believe it is an irreversible inhibitor of ethylene formation. The synthesis of these analogs has also allowed them to develop a spectroscopic technique to assign the relative stereochemistry of alkyl groups. 13 C NMR allows them to assign the alkyl stereochemistry based upon gamma-shielding effects on the carbonyl resonance. Lastly, they measured kinetic isotope effects on the oxidation of ACC in vivo and in vitro and found that ACC is oxidized by a rate-determining 1-electron removal from nitrogen in close accord with mechanisms for the oxidation of other alkyl amines

Plasmodesmata without callose and calreticulin in higher plants - open channels for fast symplastic transport?

Directory of Open Access Journals (Sweden)

Kirill N. Demchenko

2014-03-01

Full Text Available Plasmodesmata (PD represent membrane-lined channels that link adjacent plant cells across the cell wall. PD of higher plants contain a central tube of endoplasmic reticulum called desmotubule. Membrane and lumen proteins seem to be able to move through the desmotubule, but most transport processes through PD occur through the cytoplasmic annulus (Brunkard et al., 2013. Calreticulin (CRT, a highly conserved Ca2+-binding protein found in all multi-cellular eukaryotes, predominantly located in the ER, was shown to localize to PD, though not all PD accumulate CRT. In nitrogen fixing actinorhizal root nodules of the Australian tree Casuarina glauca, the primary walls of infected cells containing the microsymbiont become lignified upon infection. TEM analysis of these nodules showed that during the differentiation of infected cells, PD connecting infected cells, and connecting infected and adjacent uninfected cells, were reduced in number as well as diameter (Schubert et al., 2013. In contrast with PD connecting young infected cells, and most PD connecting mature infected and adjacent uninfected cells, PD connecting mature infected cells did not accumulate CRT. Furthermore, as shown here, these PD were not associated with callose, and based on their diameter, they probably had lost their desmotubules. We speculate that either this is a slow path to PD degradation, or that the loss of callose accumulation and presumably also desmotubules leads to the PD becoming open channels and improves metabolite exchange between cells.

Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

Directory of Open Access Journals (Sweden)

Abir U Igamberdiev

2016-07-01

Full Text Available Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve, while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve. This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.

Requirements of blue, UV-A, and UV-B light for normal growth of higher plants, as assessed by actions spectra for growth and related phenomena

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T. [Kobe Women`s Univ., Higashisuma (Japan)

1994-12-31

It is very important for experimental purposes, as well as for the practical use of plants when not enough sunlight is available. To grow green higher plants in their normal forms under artificial lighting constructing efficient and economically reasonable lighting systems is not an easy task. One possible approach would be to simulate sunlight in intensity and the radiation spectrum, but its high construction and running costs are not likely to allow its use in practice. Sunlight may be excessive in irradiance in some or all portions of the spectrum. Reducing irradiance and removing unnecessary wavebands might lead to an economically feasible light source. However, removing or reducing a particular waveband from sunlight for testing is not easy. Another approach might be to find the wavebands required for respective aspects of plant growth and to combine them in a proper ratio and intensity. The latter approach seems more practical and economical, and the aim of this Workshop lies in advancing this approach. I summarize our present knowledge on the waveband requirements of higher plants for the regions of blue, UV-A and UV-B.

LNG plant combined with power plant

Energy Technology Data Exchange (ETDEWEB)

Aoki, I; Kikkawa, Y [Chiyoda Chemical Engineering and Construction Co. Ltd., Tokyo (Japan)

1997-06-01

The LNG plant consumers a lot of power of natural gas cooling and liquefaction. In some LNG plant location, a rapid growth of electric power demand is expected due to the modernization of area and/or the country. The electric power demand will have a peak in day time and low consumption in night time, while the power demand of the LNG plant is almost constant due to its nature. Combining the LNG plant with power plant will contribute an improvement the thermal efficiency of the power plant by keeping higher average load of the power plant, which will lead to a reduction of electrical power generation cost. The sweet fuel gas to the power plant can be extracted from the LNG plant, which will be favorable from view point of clean air of the area. (Author). 5 figs.

LNG plant combined with power plant

International Nuclear Information System (INIS)

Aoki, I.; Kikkawa, Y.

1997-01-01

The LNG plant consumers a lot of power of natural gas cooling and liquefaction. In some LNG plant location, a rapid growth of electric power demand is expected due to the modernization of area and/or the country. The electric power demand will have a peak in day time and low consumption in night time, while the power demand of the LNG plant is almost constant due to its nature. Combining the LNG plant with power plant will contribute an improvement the thermal efficiency of the power plant by keeping higher average load of the power plant, which will lead to a reduction of electrical power generation cost. The sweet fuel gas to the power plant can be extracted from the LNG plant, which will be favorable from view point of clean air of the area. (Author). 5 figs

Gas exchange at whole plant level shows that a less conservative water use is linked to a higher performance in three ecologically distinct pine species

Science.gov (United States)

Salazar-Tortosa, D.; Castro, J.; Rubio de Casas, R.; Viñegla, B.; Sánchez-Cañete, E. P.; Villar-Salvador, P.

2018-04-01

Increasing temperatures and decreasing precipitation in large areas of the planet as a consequence of global warming will affect plant growth and survival. However, the impact of climatic conditions will differ across species depending on their stomatal response to increasing aridity, as this will ultimately affect the balance between carbon assimilation and water loss. In this study, we monitored gas exchange, growth and survival in saplings of three widely distributed European pine species (Pinus halepensis, P. nigra and P. sylvestris) with contrasting distribution and ecological requirements in order to ascertain the relationship between stomatal control and plant performance. The experiment was conducted in a common garden environment resembling rainfall and temperature conditions that two of the three species are expected to encounter in the near future. In addition, gas exchange was monitored both at the leaf and at the whole-plant level using a transient-state closed chamber, which allowed us to model the response of the whole plant to increased air evaporative demand (AED). P. sylvestris was the species with lowest survival and performance. By contrast, P. halepensis showed no mortality, much higher growth (two orders of magnitude), carbon assimilation (ca. 14 fold higher) and stomatal conductance and water transpiration (ca. 4 fold higher) than the other two species. As a consequence, P. halepensis exhibited higher values of water-use efficiency than the rest of the species even at the highest values of AED. Overall, the results strongly support that the weaker stomatal control of P. halepensis, which is linked to lower stem water potential, enabled this species to maximize carbon uptake under drought stress and ultimately outperform the more water conservative P. nigra and P. sylvestris. These results suggest that under a hotter drought scenario P. nigra and P. sylvestris would very likely suffer increased mortality, whereas P. halepensis could maintain

Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

Science.gov (United States)

Ferrer-Paris, José R; Sánchez-Mercado, Ada; Viloria, Ángel L; Donaldson, John

2013-01-01

We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages.

Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

Directory of Open Access Journals (Sweden)

José R Ferrer-Paris

Full Text Available We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1 is there a general correlation between host diversity and butterfly species richness?, (2 has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3 what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea and 1,193 genera (66.3%. The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp. from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae, and Satyrinae (42.6% of all Nymphalidae. We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids, but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages.

Processes for producing polyhydroxybutyrate and related polyhydroxyalkanoates in the plastids of higher plants

Science.gov (United States)

Somerville, C.R.; Nawrath, C.; Poirier, Y.

1997-03-11

The present invention relates to a process for producing poly-D-(-)-3-hydroxybutyric acid (PHB) and related polyhydroxyalkanoates (PHA) in the plastids of plants. The production of PHB is accomplished by genetically transforming plants with modified genes from microorganisms. The genes encode the enzymes required to synthesize PHB from acetyl-CoA or related metabolites and are fused with additional plant sequences for targeting the enzymes to the plastid. 37 figs.

Conservation between higher plants and the moss Physcomitrella patens in response to the phytohormone abscisic acid: a proteomics analysis

Directory of Open Access Journals (Sweden)

Wang Xiaoqin

2010-08-01

accumulation levels as a result of treatment with ABA. Detailed analysis these protein functions showed that physiological and molecular responses to the plant hormone ABA appear to be conserved among higher plant species and bryophytes.

Optimization of animal manure vermicomposting based on biomass production of earthworms and higher plants.

Science.gov (United States)

Borges, Yan V; Alves, Luciano; Bianchi, Ivan; Espíndola, Jonas C; Oliveira, Juahil M De; Radetski, Claudemir M; Somensi, Cleder A

2017-11-02

The goal of this study was to optimize the mixture of swine manure (SM) and cattle manure (CM) used in the vermicomposting process, seeking to increase the manure biodegradation rate and enhance the biomass production of both earthworms and higher plants. To achieve this goal, physico-chemical parameters were determined to assess the final compost quality after 50 days of vermicomposting. The different manure ratios used to produce the composts (C) were as follows (SM:CM, % m/m basis): C1 100:0, C2 (75:25), C3 (50:50), C4 (25:75), and C5 (0:100). In addition, the earthworm biomass and the phytoproductivity of lettuce (Lactuca sativa L.) plants grown in mixtures (1:1) of natural soil and the most viable vermicomposts were investigated. The C1 and C2 compost compositions were associated with high earthworm mortality rates. The C3 compost provided the highest mineral concentrations and C5 showed the highest lettuce yield (wet biomass). The results verify that stabilized cattle manure is an excellent substrate for the vermicomposting process and that fresh swine manure must be mixed with pre-stabilized cattle manure to ensure an optimized vermicomposting process, which must be controlled in terms of temperature and ammonia levels. It is concluded that small livestock farmers could add value to swine manure by applying the vermicomposting process, without the need for high investments and with a minimal requirement for management of the biodegradation process. These are important technical aspects to be considered when circular economy principles are applied to small farms.

Plants and men in space - A new field in plant physiology

Science.gov (United States)

Andre, M.; Macelroy, R. D.

1990-01-01

Results are presented on a comparison of nutritional values of and human psychological responses to algae and of higher plants considered for growth as food on long-term missions in space, together with the technological complexities of growing these plants. The comparison shows the advantages of higher plants, with results suggesting that a high level of material recycling can be obtained. It is noted that the issue of space gravity may be not a major problem for plants because of the possibility that phototropism can provide an alternative sense of direction. Problems of waste recycling can be solved in association with plant cultivation, and a high degree of autonomy of food production can be obtained.

Engineering of plants with improved properties as biofuels feedstocks by vessel-specific complementation of xylan biosynthesis mutants

Directory of Open Access Journals (Sweden)

Petersen Pia Damm

2012-11-01

Full Text Available Abstract Background Cost-efficient generation of second-generation biofuels requires plant biomass that can easily be degraded into sugars and further fermented into fuels. However, lignocellulosic biomass is inherently recalcitrant toward deconstruction technologies due to the abundant lignin and cross-linked hemicelluloses. Furthermore, lignocellulosic biomass has a high content of pentoses, which are more difficult to ferment into fuels than hexoses. Engineered plants with decreased amounts of xylan in their secondary walls have the potential to render plant biomass a more desirable feedstock for biofuel production. Results Xylan is the major non-cellulosic polysaccharide in secondary cell walls, and the xylan deficient irregular xylem (irx mutants irx7, irx8 and irx9 exhibit severe dwarf growth phenotypes. The main reason for the growth phenotype appears to be xylem vessel collapse and the resulting impaired transport of water and nutrients. We developed a xylan-engineering approach to reintroduce xylan biosynthesis specifically into the xylem vessels in the Arabidopsis irx7, irx8 and irx9 mutant backgrounds by driving the expression of the respective glycosyltransferases with the vessel-specific promoters of the VND6 and VND7 transcription factor genes. The growth phenotype, stem breaking strength, and irx morphology was recovered to varying degrees. Some of the plants even exhibited increased stem strength compared to the wild type. We obtained Arabidopsis plants with up to 23% reduction in xylose levels and 18% reduction in lignin content compared to wild-type plants, while exhibiting wild-type growth patterns and morphology, as well as normal xylem vessels. These plants showed a 42% increase in saccharification yield after hot water pretreatment. The VND7 promoter yielded a more complete complementation of the irx phenotype than the VND6 promoter. Conclusions Spatial and temporal deposition of xylan in the secondary cell wall of

PHYSIOLOGY OF ION TRANSPORT ACROSS THE TONOPLAST OF HIGHER PLANTS.

Science.gov (United States)

Barkla, Bronwyn J.; Pantoja, Omar

1996-06-01

The vacuole of plant cells plays an important role in the homeostasis of the cell. It is involved in the regulation of cytoplasmic pH, sequestration of toxic ions and xenobiotics, regulation of cell turgor, storage of amino acids, sugars and CO2 in the form of malate, and possibly as a source for elevating cytoplasmic calcium. All these activities are driven by two primary active transport mechanisms present in the vacuolar membrane (tonoplast). These two mechanisms employ high-energy metabolites to pump protons into the vacuole, establishing a proton electrochemical potential that mediates the transport of a diverse range of solutes. Within the past few years, great advances at the molecular and functional levels have been made on the characterization and identification of these mechanisms. The aim of this review is to summarize these studies in the context of the physiology of the plant cell.

Red mud a byproduct of aluminum production contains soluble vanadium that causes genotoxic and cytotoxic effects in higher plants

Energy Technology Data Exchange (ETDEWEB)

Mišík, Miroslav [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Burke, Ian T. [Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Reismüller, Matthias; Pichler, Clemens; Rainer, Bernhard [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Mišíková, Katarina [Department of Botany, Faculty of Natural Sciences, Comenius University, Bratislava (Slovakia); Mayes, William M. [Centre for Environmental and Marine Sciences, University of Hull, Scarborough YO11 3AZ (United Kingdom); Knasmueller, Siegfried, E-mail: siegfried.knasmueller@meduniwien.ac.at [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria)

2014-09-15

Red mud (RM) is a byproduct of aluminum production; worldwide between 70 and 120 million tons is produced annually. We analyzed RM which was released in the course of the Kolontar disaster in Hungary into the environment in acute and genotoxicity experiments with plants which are widely used for environmental monitoring. We detected induction of micronuclei which reflect chromosomal damage in tetrads of Tradescantia and in root cells of Allium as well as retardation of root growth with contaminated soils and leachates. Chemical analyses showed that RM contains metals, in particular high concentrations of vanadium. Follow-up experiments indicated that vanadate causes the effects in the plants. This compound causes also in humans DNA damage and positive results were obtained in carcinogenicity studies. Since it was found also in RM from other production sites our findings indicate that its release in the environment is a global problem which should be studied in more detail. Capsule abstract: Our findings indicate that the red mud causes genotoxic effect in plants probably due to the presence of vanadate which is contained at high concentrations in the residue. - Highlights: • Red mud, a by-product of aluminum production, causes DNA-damage in higher plants. • We showed that this effect is caused by vanadate a known carcinogenic genotoxin. • Vanadate is contained in high concentrations in the residue. • Release of red mud may cause adverse effects in ecosystems and affect human health.

AMT1;1 transgenic rice plants with enhanced NH4(+) permeability show superior growth and higher yield under optimal and suboptimal NH4(+) conditions.

Science.gov (United States)

Ranathunge, Kosala; El-Kereamy, Ashraf; Gidda, Satinder; Bi, Yong-Mei; Rothstein, Steven J

2014-03-01

The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4(+)). The NH4(+) uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4(+) transport in rice plants. However, little is known about its involvement in NH4(+) uptake in rice roots and subsequent effects on NH4(+) assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4(+) permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4(+) content in the shoots and roots than the WT. Direct NH4(+) fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4(+) contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4(+) levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions.

AMT1;1 transgenic rice plants with enhanced NH4 + permeability show superior growth and higher yield under optimal and suboptimal NH4 + conditions

Science.gov (United States)

Rothstein, Steven J.

2014-01-01

The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4 +). The NH4 + uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4 + transport in rice plants. However, little is known about its involvement in NH4 + uptake in rice roots and subsequent effects on NH4 + assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4 + permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4 + content in the shoots and roots than the WT. Direct NH4 + fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4 + contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4 + levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions. PMID:24420570

Suppression of the invasive plant mile-a-minute (Mikania micrantha) by local crop sweet potato (Ipomoea batatas) by means of higher growth rate and competition for soil nutrients.

Science.gov (United States)

Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Chen, Aidong; Zhang, Fudou; Kato-Noguchi, Hisashi

2015-01-28

There are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-a-minute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m(2) plots. In monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P competition of sweet potato in the mixture. Evidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet potatoes. This study also shows the potential value of replacement control methods which may apply to other crop-weed systems or invaded natural ecosystems.

Comparative studies on the photosynthesis of higher plants, 4

International Nuclear Information System (INIS)

Imai, Hideo; Iwai, Sumio; Yamada, Yoshio.

1975-01-01

In this paper, studies were carried out to confirm whether carbon atoms except C-4 of C 4 -compounds were involved in the photosynthetic sugar formation in C 4 plants. In feeding of uniformly-labeled malate to maize leaves, sugar formation under aerobic conditions was 3 times as large as that under anaerobic conditions. There was no detectable difference in the amount of activity in the sugar formed from β-carboxyl-labeled malate between aerobic and anaerobic conditions; however. Under anaerobic conditions, sugar was formed from alanine-1- 14 C in maize but not in rice leaves. Sugar formation of this case might have occurred by the direct conversion of pyruvate to sugar via PEP and PGA. From these results, we assume that the following three pathways function cooperatively in the photosynthetic sugar formation in C 4 -plants. 1) One carbon atom at number 4 in C 4 -dicarboxylic acid is transferred to RuDP, resulting in the formation of PGA and this is metabolized into sugar. 2) After transferring C-4 of C 4 -dicarboxylic acid, the remaining C 3 -compound is introduced into the TCA cycle and completely degradated there, and thus-produced CO 2 is refixed by PEP carboxylase in the mesophyll and metabolized into sugar the same pathway as in atmospheric CO 2 fixation. 3) The remaining C 3 -compound is directly converted to PEP and then to sugar via PGA. (auth.)

Integrated Gasification SOFC Plant with a Steam Plant

DEFF Research Database (Denmark)

Rokni, Masoud; Pierobon, Leonardo

2011-01-01

A hybrid Solid Oxide Fuel Cell (SOFC) and Steam Turbine (ST) plant is integrated with a gasification plant. Wood chips are fed to the gasification plant to produce biogas and then this gas is fed into the anode side of a SOFC cycle to produce electricity and heat. The gases from the SOFC stacks...... enter into a burner to burn the rest of the fuel. The offgases after the burner are now used to generate steam in a Heat Recovery Steam Generator (HRSG). The generated steam is expanded in a ST to produce additional power. Thus a triple hybrid plant based on a gasification plant, a SOFC plant...... and a steam plant is presented and studied. The plant is called as IGSS (Integrated Gasification SOFC Steam plant). Different systems layouts are presented and investigated. Electrical efficiencies up to 56% are achieved which is considerably higher than the conventional integrated gasification combined...

Plant Research '75

Energy Technology Data Exchange (ETDEWEB)

1975-01-01

Research is reported on stomatal regulation of the gas exchanges between plant and environment; inhibitory effects in flower formation; plant growth and development through hormones; hormone action; development and nitrogen fixation in algae; primary cell wall glycoprotein ectensin; enzymic mechanisms and control of polysaccharide and glycoprotein synthesis; molecular studies of membrane studies; sensory transduction in plants; regulation of formation of protein complexes and enzymes in higher plant cell and mechanism of sulfur dioxide toxicity in plants. (PCS)

Effective integration between heavy water plant and fertilizer plant for higher production of heavy water (D2O) (Preprint No. PD-10)

International Nuclear Information System (INIS)

Periakaruppan, M.; Gupta, S.K.; Bhowmick, S.C.

1989-04-01

For smooth and efficient running of heavy water plants linked with fertilize r plants, it is necessary that certain factors must be taken into consideration right from the design stage of a fertilizer plant. These factors are: (1)preventing loss in D 2 concentration in syn gas, (2)keeping the level of CO 2 and CO in syn gas below 1 ppm, (3)operating the ammonia plant at highest pressure and (4)keeping the feed gas ammonia supply available without any interruption. Incorporation of these factors in the design is discussed. (M.G.B. )

The photosynthetic response of tobacco plants overexpressing ice plant aquaporin McMIPB to a soil water deficit and high vapor pressure deficit.

Science.gov (United States)

Kawase, Miki; Hanba, Yuko T; Katsuhara, Maki

2013-07-01

We investigated the photosynthetic capacity and plant growth of tobacco plants overexpressing ice plant (Mesembryanthemum crystallinum L.) aquaporin McMIPB under (1) a well-watered growth condition, (2) a well-watered and temporal higher vapor pressure deficit (VPD) condition, and (3) a soil water deficit growth condition to investigate the effect of McMIPB on photosynthetic responses under moderate soil and atmospheric humidity and water deficit conditions. Transgenic plants showed a significantly higher photosynthesis rate (by 48 %), higher mesophyll conductance (by 52 %), and enhanced growth under the well-watered growth condition than those of control plants. Decreases in the photosynthesis rate and stomatal conductance from ambient to higher VPD were slightly higher in transgenic plants than those in control plants. When plants were grown under the soil water deficit condition, decreases in the photosynthesis rate and stomatal conductance were less significant in transgenic plants than those in control plants. McMIPB is likely to work as a CO2 transporter, as well as control the regulation of stomata to water deficits.

Maize yield and quality in response to plant density and application of a novel plant growth regulator

NARCIS (Netherlands)

Zhang, Q.; Zhang, L.; Evers, J.B.; Werf, van der W.; Zhang, W.; Duan, L.

2014-01-01

Farmers in China have gradually increased plant density in maize to achieve higher yields, but this has increased risk of lodging due to taller and weaker stems at higher plant densities. Plant growth regulators can be used to reduce lodging risk. In this study, for the first time, the performance

Utilization of the higher plants in a study on hereditary effect of low-dose irradiation

International Nuclear Information System (INIS)

Yamashita, Jun

1976-01-01

Some problems in a study of hereditary effect of low-dose irradiation, which used the higher plants (tradescantia, peas, etc.) as materials, were mentioned. Conditions to be used as materials were mentioned as follows: 1) the materials must have high radio-sensitivity, 2) the natural mutation of the materials must be low, 3) hereditary uniformity and stability of genes in the materials were important, and 4) in case of considering the materials as environmental radiation monitors, the observation period must be long and the duration from exposure to detection of mutation must be short. Tradescantia has most of these conditions, but the greatest fault is that the object of its observation is mutation of somatic cells, and hereditary study is impossible. Therefore, it is necessary to find out other materials in order to solve the problem whether there is a difference in relative frequency of chromosomal abnormalities, which occurrs in germinal cells and is transmitted to posterity, between low and high doses or not. (Serizawa, K.)

PsbS-specific zeaxanthin-independent changes in fluorescence emission spectrum as a signature of energy-dependent non-photochemical quenching in higher plants.

Science.gov (United States)

Zulfugarov, Ismayil S; Tovuu, Altanzaya; Dogsom, Bolormaa; Lee, Chung Yeol; Lee, Choon-Hwan

2010-05-01

The PsbS protein of photosystem II is necessary for the development of energy-dependent quenching of chlorophyll (Chl) fluorescence (qE), and PsbS-deficient Arabidopsis plant leaves failed to show qE-specific changes in the steady-state 77 K fluorescence emission spectra observed in wild-type leaves. The difference spectrum between the quenched and un-quenched states showed a negative peak at 682 nm. Although the level of qE development in the zeaxanthin-less npq1-2 mutant plants, which lacked violaxanthin de-epoxidase enzyme, was only half that of wild type, there were no noticeable changes in this qE-dependent difference spectrum. This zeaxanthin-independent DeltaF682 signal was not dependent on state transition, and the signal was not due to photobleaching of pigments either. These results suggest that DeltaF682 signal is formed due to PsbS-specific conformational changes in the quenching site of qE and is a new signature of qE generation in higher plants.

Generation of poly-β-hydroxybutyrate from acetate in higher plants: Detection of acetoacetyl CoA reductase- and PHB synthase- activities in rice.

Science.gov (United States)

Tsuda, Hirohisa; Shiraki, Mari; Inoue, Eri; Saito, Terumi

2016-08-20

It has been reported that Poly-β-hydroxybutyrate (PHB) is generated from acetate in the rice root. However, no information is available about the biosynthetic pathway of PHB from acetate in plant cells. In the bacterium Ralstonia eutropha H16 (R. eutropha), PHB is synthesized from acetyl CoA by the consecutive reaction of three enzymes: β-ketothiolase (EC: 2.3.1.9), acetoacetyl CoA reductase (EC: 1.1.1.36) and PHB synthase (EC: 2.3.1.-). Thus, in this study, we examined whether the above three enzymatic activities were also detected in rice seedlings. The results clearly showed that the activities of the above three enzymes were all detected in rice. In particular, the PHB synthase activity was detected specifically in the sonicated particulate fractions (2000g 10min precipitate (ppt) and the 8000g 30min ppt) of rice roots and leaves. In addition to these enzyme activities, several new experimental results were obtained on PHB synthesis in higher plants: (a) (14)C-PHB generated from 2-(14)C-acetate was mainly localized in the 2000g 10min ppt and the 8000g 30min ppt of rice root. (b) Addition of acetate (0.1-10mM) to culture medium of rice seedlings did not increase the content of PHB in the rice root or leaf. (c) In addition to C3 plants, PHB was generated from acetate in a C4 plant (corn) and in a CAM plant (Bryophyllum pinnatum). d) Washing with ethylenediaminetetraacetic acid (EDTA) strongly suggested that the PHB synthesized from acetate was of plant origin and was not bacterial contamination. Copyright © 2016 Elsevier GmbH. All rights reserved.

PV integration into a CSP plant

Science.gov (United States)

Carvajal, Javier López; Barea, Jose M.; Barragan, Jose; Ortega, Carlos

2017-06-01

This paper describes a preliminary techno-economic analysis of the integration of a PV plant into an optimized Parabolic Trough Plant in order to reduce the online consumptions and thus, increase the net electricity injected into the grid. The idea is to assess the feasibility of such project and see what configuration would be the optimal. An extra effort has been made in terms of modelling as the analysis has to be done to the integrated CSP + PV plant instead of analyzing them independently. Two different technologies have been considered for the PV plant, fix and one-axis tracking. Additionally three different scenarios have been considered for the CSP plant auxiliary consumptions as they are essential for determining the optimal PV plant (the higher the auxiliary consumption the higher the optimal PV plant). As could be expected, the results for all cases with PV show an improvement in terms of electricity generation and also in terms of LCOE with respect to the CSP plant. Such improvement is slightly higher with tracking technology for this specific study. Although this exercise has been done to an already designed CSP plant (so only the PV plant had to be optimized), the methodology could be applied for the optimization of an integrated CSP + PV plant during the design phase.

Experimental studies on SO/sub 2/ injuries in higher plants. Part 4

Energy Technology Data Exchange (ETDEWEB)

Tanaka, H; Takanashi, T; Yatazawa, M

1970-01-01

The effect of sulfur dioxide on aminoacid metabolism was examined. Wheat seedlings one month old (20 cm) were exposed to 0.5 ppm SO/sub 2/ at 22/sup 0/C, and 40% humidity for four days, only during the day. A Beckman 1200 aminoacid analyzer revealed only slight effects, but it was conjectured that the plant had some separate amino acid in its body prior to the test, and that the effect of SO/sub 2/ was relatively low. A similar wheat seedling was placed in a closed glass container and was exposed to 300 ppm carbon dioxide (14) and 100 ppm SO/sub 2/ for 30 min under 4000 lux. The first paper chromatography of 80% ethanol solubles from the leaves revealed that Ala. value had increased but sir. had decreased in half. The second paper chromatography revealed that in both test and control plants, four kinds of material in amino acid had taken in C(14), and two of the four were Ser. Ala. The total C(14) taken in by the test material under SO/sub 2/ exposure showed a noted decrease. The experiment proved that exposure of a plant to a high concentration of SO/sub 2/ produced hydroxysulfonate in metabolism and impaired its glycol acid function.

[Distribution of HCB discharged from a chemical plant in plants].

Science.gov (United States)

Chen, Jing; Wang, Lin-Ling; Lu, Xiao-Hua; Yuan, Song-Hu; Liu, Xi-Xiang; Wang, Yue; Zhao, Qian; Mei, Ling-Fang

2009-04-15

The distribution characteristics of hexachlorobenzene (HCB) in plant and rhizosphere soil in contamination conduit, a nearby river and a cropland were studied and the impact factors were also discussed. The results are summarized as follows: the range of the HCB concentration in plant and rhizosphere soil in investigation area were respectively from 4.45 microg x kg(-1) to 1,189.89 microg x kg(-1) (dw) and from 27.93 microg x kg(-1) to 3,480.71 microg x kg(-1) (dw). Higher enrichment of HCB in woodplant than herbs due to higher fat concentration in woodplant in the contamination conduit and the rich concentrtion factor of woodplant and herbs were 0.41-2.55 and 0.01-1.34. The range of HCB concentrations in plants in nearby croplands was significantly wide (4.45-333.1 microg x kg(-1)) while HCB concentrations in different parts of plant were various, e.g. HCB concentrations in fruit, root and shoot of taro were 318.77 microg x kg(-1), 281.02 microg x kg(-1) and 10.94 microg x kg(-1). There was a remarkable positive relation between the concentrations of HCB in plant and fat concentration of plant while no relativity between the concentrations of HCB in plant and those in ground soils in the contamination conduit and cropland. The concentration levels of HCB in plant and rhizosphere soil in river were dramatically decreased with increasing distance from contaminated conduit. There was a remarkable positive relation between the concentrations of HCB in plant and those in ground soils but no relation between concentrations of HCB in plant and fat concentration of plant in river. The distribution characteristics of HCB in plants were influenced by contaminated levels, fat concentration and Partition-transfer model.

Populations in clonal plants

Directory of Open Access Journals (Sweden)

Jussi Tammisola

1986-12-01

Full Text Available Population phenomena in higher plants are reviewed critically, particularly in relation to clonality. An array of concepts used in the field are discussed. In contrast to animals, higher plants are modular in structure. Plant populations show hierarchy at two levels: ramets and genets. In addition, their demography is far more complicated, since even the direction of development of a ramet may change by rejuvenation. Therefore, formulae concerning animal populations often require modification for plants. Furthermore, at the zygotic stage, higher plants are generally less mobile than animals. Accordingly, their population processes tend to be more local. Most populations of plants have a genetic structure: alleles and genotypes are spatially aggregated. Due to the short-ranged foraging behaviour of pollinators, genetically non-random pollination prevails. A generalized formula for parent-offspring dispersal variance is derived. It is used to analyze the effect of clonality on genetic patchiness in populations. In self-compatible species, an increase in clonality will tend to increase the degree of patchiness, while in self-incompatible species a decrease may result. Examples of population structure studies in different species are presented. A considerable degree of genetic variation appears to be found also in the populations of species with a strong allocation of resources to clonal growth or apomictic seed production. Some consequences of clonality are considered from the point of view of genetic conservation and plant breeding.

Metabolism of ibuprofen in higher plants: A model Arabidopsis thaliana cell suspension culture system

Czech Academy of Sciences Publication Activity Database

Maršík, Petr; Šíša, Miroslav; Lacina, O.; Moťková, Kateřina; Langhansová, Lenka; Rezek, Jan; Vaněk, Tomáš

2017-01-01

Roč. 220, JAN (2017), s. 383-392 ISSN 0269-7491 R&D Projects: GA ČR(CZ) GA14-22593S Grant - others:European Regional Development Fund(XE) CZ.2.16/3.1.00/24014 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * Ibuprofen * Metabolism * Plant cells * Sequestration Subject RIV: CE - Biochemistry OBOR OECD: Plant sciences, botany Impact factor: 5.099, year: 2016

Higher operational safety of nuclear power plants by evaluating the behaviour of operating personnel

International Nuclear Information System (INIS)

Mertins, M.; Glasner, P.

1990-01-01

In the GDR power reactors have been operated since 1966. Since that time operational experiences of 73 cumulative reactor years have been collected. The behaviour of operating personnel is an essential factor to guarantee the safety of operation of the nuclear power plant. Therefore a continuous analysis of the behaviour of operating personnel has been introduced at the GDR nuclear power plants. In the paper the overall system of the selection, preparation and control of the behaviour of nuclear power plant operating personnel is presented. The methods concerned are based on recording all errors of operating personnel and on analyzing them in order to find out the reasons. The aim of the analysis of reasons is to reduce the number of errors. By a feedback of experiences the nuclear safety of the nuclear power plant can be increased. All data necessary for the evaluation of errors are recorded and evaluated by a computer program. This method is explained thoroughly in the paper. Selected results of error analysis are presented. It is explained how the activities of the personnel are made safer by means of this analysis. Comparisons with other methods are made. (author). 3 refs, 4 figs

Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

Directory of Open Access Journals (Sweden)

Durgesh K. Tripathi

2018-02-01

Full Text Available Iron (Fe is a micronutrient that plays an important role in agriculture worldwide because plants require a small amount of iron for its growth and development. All major functions in a plant's life from chlorophyll biosynthesis to energy transfer are performed by Fe (Brumbarova et al., 2008; Gill and Tuteja, 2011. Iron also acts as a major constituent of many plant proteins and enzymes. The acquisition of Fe in plants occurs through two strategies, i.e., strategy I and strategy II (Marschner and Römheld, 1994. Under various stress conditions, Nramp and the YSL gene families help in translocation of Fe, which further acts as a mineral regulatory element and defends plants against stresses. Iron plays an irreplaceable role in alleviating stress imposed by salinity, drought, and heavy metal stress. This is because it activates plant enzymatic antioxidants like catalase (CAT, peroxidase, and an isoform of superoxide dismutase (SOD that act as a scavenger of reactive oxygen species (ROS (Hellin et al., 1995. In addition to this, their deficiency as well as their excess amount can disturb the homeostasis of a plant's cell and result in declining of photosynthetic rate, respiration, and increased accumulation of Na+ and Ca− ions which culminate in an excessive formation of ROS. The short-range order hydrated Fe oxides and organic functional groups show affinities for metal ions. Iron plaque biofilm matrices could sequester a large amount of metals at the soil–root interface. Hence, it has attracted the attention of plant physiologists and agricultural scientists who are discovering more exciting and hidden applications of Fe and its potential in the development of bio-factories. This review looks into the recent progress made in putting forward the role of Fe in plant growth, development, and acclimation under major abiotic stresses, i.e., salinity, drought, and heavy metals.

Plant neighbor identity influences plant biochemistry and physiology related to defense.

Science.gov (United States)

Broz, Amanda K; Broeckling, Corey D; De-la-Peña, Clelia; Lewis, Matthew R; Greene, Erick; Callaway, Ragan M; Sumner, Lloyd W; Vivanco, Jorge M

2010-06-17

Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors. In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa) or heterospecific (Festuca idahoensis) plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics. Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success.

Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.

Science.gov (United States)

Rogalski, Marcelo; Carrer, Helaine

2011-06-01

The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

Optimal planting systems for cut gladiolus and stock production

Directory of Open Access Journals (Sweden)

Iftikhar Ahmad

2017-10-01

Full Text Available A study was conducted to elucidate the effect of different planting systems, videlicet (viz. flat, ridge, and raised bed system on growth, yield and quality of gladiolus and stock. Corms of ‘Rose Supreme’ and ‘White Prosperity’ gladiolus and seedlings of ‘Cheerful White’, ‘Lucinda Dark Rose Double’ and ‘Lucinda Dark Rose Single’ stock were planted on different planting systems in individual experiments for each species. Gladiolus had similar good quality production irrespective of planting systems with numerical superiority of ridge planting, which produced longer stems with higher stem fresh weight, but delayed corm sprouting by ca. 1 d compared to raised bed or flat planting system. Among cultivars, ‘Rose Supreme’ produced higher number of florets per spike, taller stems with longer spikes, higher fresh weight of stems and higher number of cormels than ‘White Prosperity’. Stock plants grown on flat beds produced stems with greater stem length, leaf area and fresh weight of stems compared to ridge or raised bed planting systems. Plants grown on ridges produced the highest stem diameter, number of leaves per plant, total leaf chlorophyll contents, and number of flowers per spike. ‘Cheerful White’ and ‘Lucinda Dark Rose Double’ performed best by producing good quality stems in shorter period compared to ‘Lucinda Dark Rose Single’. In summary, gladiolus should be grown on ridges, while stock may be planted on flat beds for higher yields of better quality flowers.

Electronic plants

Science.gov (United States)

Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

2015-01-01

The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

Bi-functional glycosyltransferases catalyze both extension and termination of pectic galactan oligosaccharides

DEFF Research Database (Denmark)

Laursen, Tomas; Stonebloom, Solomon H; Pidatala, Venkataramana R

2018-01-01

. Transfer of Arap to galactan prevents further addition of galactose residues, resulting in a lower degree of polymerization. We show that this dual activity occurs both in vitro and in vivo. The herein described bi-functionality of AtGALS1 may suggest that plants can produce the incredible structural...

A protochlorophyllide light-harvesting complex involved in de-etiolation of higher plants

International Nuclear Information System (INIS)

Reinbothe, C.; Lebedev, N.; Reinbothe, S.

1999-01-01

When etiolated angiosperm seedlings break through the soil after germination, they are immediately exposed to sunlight, but at this stage they are unable to perform photosynthesis1. In the absence of chlorophyll a and chlorophyll b, two other porphyrin species cooperate as the basic light-harvesting structure of etiolated plants. Protochlorophyllide a and protochlorophyllide b (ref. 2) form supramolecular complexes with NADPH and two closely related NADPH:protochlorophyllide oxidoreductase (POR) proteins—PORA and PORB (ref. 3)—in the prolamellar body of etioplasts. Here we report that these light-harvesting POR–protochlorophyllide complexes, named LHPP, are essential for the establishment of the photosynthetic apparatus and also confer photoprotection on the plant. They collect sunlight for rapid chlorophyll a biosynthesis and, simultaneously, dissipate excess light energy in the bulk of non-photoreducible protochlorophyllide b. Based on this dual function, it seems that LHPP provides the link between skotomorphogenesis and photosynthesis that is required for efficient de-etiolation

One-pot multienzyme (OPME) systems for chemoenzymatic synthesis of carbohydrates.

Science.gov (United States)

Yu, Hai; Chen, Xi

2016-03-14

Glycosyltransferase-catalyzed enzymatic and chemoenzymatic syntheses are powerful approaches for the production of oligosaccharides, polysaccharides, glycoconjugates, and their derivatives. Enzymes involved in the biosynthesis of sugar nucleotide donors can be combined with glycosyltransferases in one pot for efficient production of the target glycans from simple monosaccharides and acceptors. The identification of enzymes involved in the salvage pathway of sugar nucleotide generation has greatly facilitated the development of simplified and efficient one-pot multienzyme (OPME) systems for synthesizing major glycan epitopes in mammalian glycomes. The applications of OPME methods are steadily gaining popularity mainly due to the increasing availability of wild-type and engineered enzymes. Substrate promiscuity of these enzymes and their mutants allows OPME synthesis of carbohydrates with naturally occurring post-glycosylational modifications (PGMs) and their non-natural derivatives using modified monosaccharides as precursors. The OPME systems can be applied in sequence for synthesizing complex carbohydrates. The sequence of the sequential OPME processes, the glycosyltransferase used, and the substrate specificities of the glycosyltransferases define the structures of the products. The OPME and sequential OPME strategies can be extended to diverse glycans in other glycomes when suitable enzymes with substrate promiscuity become available. This Perspective summarizes the work of the authors and collaborators on the development of glycosyltransferase-based OPME systems for carbohydrate synthesis. Future directions are also discussed.

Gangliosides in the Nervous System: Biosynthesis and Degradation

Science.gov (United States)

Yu, Robert K.; Ariga, Toshio; Yanagisawa, Makoto; Zeng, Guichao

Gangliosides, abundant in the nervous system, are known to play crucial modulatory roles in cellular recognition, interaction, adhesion, and signal transduction, particularly during early developmental stages. The expression of gangliosides in the nervous system is developmentally regulated and is closely related to the differentiation state of the cell. Ganglioside biosynthesis occurs in intracellular organelles, from which gangliosides are transported to the plasma membrane. During brain development, the ganglioside composition of the nervous system undergoes remarkable changes and is strictly regulated by the activities of glycosyltransferases, which can occur at different levels of control, including glycosyltransferase gene transcription and posttranslational modification. Genes for glycosyltransferase involved in ganglioside biosynthesis have been cloned and classified into families of glycosyltransferases based on their amino acid sequence similarities. The donor and acceptor substrate specificities are determined by enzymatic analysis of the glycosyltransferase gene products. Cell-type specific regulation of these genes has also been studied. Gangliosides are degraded by lysosomal exoglycosidases. The action of these enzymes occurs frequently in cooperation with activator proteins. Several human diseases are caused by defects of degradative enzymes, resulting in massive accumulation of certain glycolipids, including gangliosides in the lysosomal compartment and other organelles in the brain and visceral organs. Some of the representative lysosomal storage diseases (LSDs) caused by the accumulation of lipids in late endosomes and lysosomes will be discussed.

Plant neighbor identity influences plant biochemistry and physiology related to defense

Directory of Open Access Journals (Sweden)

Callaway Ragan M

2010-06-01

Full Text Available Abstract Background Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors. Results In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa or heterospecific (Festuca idahoensis plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics. Conclusions Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success.

Understanding water deficit stress-induced changes in the basic metabolism of higher plants - biotechnologically and sustainably improving agriculture and the ecoenvironment in arid regions of the globe.

Science.gov (United States)

Shao, Hong-Bo; Chu, Li-Ye; Jaleel, C Abdul; Manivannan, P; Panneerselvam, R; Shao, Ming-An

2009-01-01

Water is vital for plant growth, development and productivity. Permanent or temporary water deficit stress limits the growth and distribution of natural and artificial vegetation and the performance of cultivated plants (crops) more than any other environmental factor. Productive and sustainable agriculture necessitates growing plants (crops) in arid and semiarid regions with less input of precious resources such as fresh water. For a better understanding and rapid improvement of soil-water stress tolerance in these regions, especially in the water-wind eroded crossing region, it is very important to link physiological and biochemical studies to molecular work in genetically tractable model plants and important native plants, and further extending them to practical ecological restoration and efficient crop production. Although basic studies and practices aimed at improving soil water stress resistance and plant water use efficiency have been carried out for many years, the mechanisms involved at different scales are still not clear. Further understanding and manipulating soil-plant water relationships and soil-water stress tolerance at the scales of ecology, physiology and molecular biology can significantly improve plant productivity and environmental quality. Currently, post-genomics and metabolomics are very important in exploring anti-drought gene resources in various life forms, but modern agriculturally sustainable development must be combined with plant physiological measures in the field, on the basis of which post-genomics and metabolomics have further practical prospects. In this review, we discuss physiological and molecular insights and effects in basic plant metabolism, drought tolerance strategies under drought conditions in higher plants for sustainable agriculture and ecoenvironments in arid and semiarid areas of the world. We conclude that biological measures are the bases for the solutions to the issues relating to the different types of

Radioecological investigations of phytocommunities higher water plant in upper Kiev water reservoir

International Nuclear Information System (INIS)

Pan'kov, I.V.; Volkova, E.N.; Shirokaya, Z.O.; Karapish, V.A.; Dremlyuga, S.V.

1997-01-01

The dose loads of the highest water plants it determined and ecological role of phytocommunities in radionuclides distribution and migration in water reservoir is shown. The ' critical zones ' for characteristic types of phytocommunities are determined. It is marked that radionuclides accumulation by macrophits depends on species and ecological group

Does chemical aposematic (warning) signaling occur between host plants and their potential parasitic plants?

Science.gov (United States)

Lev-Yadun, Simcha

2013-07-01

Aposematism (warning) signaling is a common defensive mechanism toward predatory or herbivorous animals, i.e., interactions between different trophic levels. I propose that it should be considered at least as a working hypothesis that chemical aposematism operates between certain host plants and their plant predators, parasitic plants, and that although they are also plants, they belong to a higher trophic level. Specific host plant genotypes emit known repelling chemical signals toward parasitic plants, which reduce the level of, slow the directional parasite growth (attack) toward the signaling hosts, or even cause parasitic plants to grow away from them in response to these chemicals. Chemical host aposematism toward parasitic plants may be a common but overlooked defense from parasitic plants.

Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

Science.gov (United States)

Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

2015-12-01

Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences. © 2015 John Wiley & Sons Ltd/CNRS.

Plant-based remediation processes

Energy Technology Data Exchange (ETDEWEB)

Gupta, Dharmendra Kumar (ed.) [Belgian Nuclear Research Centre (SCK.CEN), Mol (Belgium). Radiological Impact and Performance Assessment Division

2013-11-01

A valuable source of information for scientists in the field of environmental pollution and remediation. Describes the latest biotechnological methods for the treatment of contaminated soils. Includes case studies and protocols. Phytoremediation is an emerging technology that employs higher plants for the clean-up of contaminated environments. Basic and applied research have unequivocally demonstrated that selected plant species possess the genetic potential to accumulate, degrade, metabolize and immobilize a wide range of contaminants. The main focus of this volume is on the recent advances of technologies using green plants for remediation of various metals and metalloids. Topics include biomonitoring of heavy metal pollution, amendments of higher uptake of toxic metals, transport of heavy metals in plants, and toxicity mechanisms. Further chapters discuss agro-technological methods for minimizing pollution while improving soil quality, transgenic approaches to heavy metal remediation and present protocols for metal remediation via in vitro root cultures.

Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

Science.gov (United States)

Rosenthal, Cindy; Mueller, Uwe; Panjikar, Santosh; Sun, Lianli; Ruppert, Martin; Zhao, Yu; Stöckigt, Joachim

2006-01-01

Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C2221 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å. PMID:17142919

High temperature reactor module power plant. Plant and safety concept June 1986 - 38.07126.2

International Nuclear Information System (INIS)

1986-06-01

The modular HTR power plant is a universally applicable energy source for the co-generation of electricity, process steam or district heating. The modular HTR concept is characterized by the fact that standardized reactor units with power ratings of 200 MJ/s (so-called modules) can be combined to form power plants with a higher power rating. Consequently the special safety features of small high-temperature reactors (HTR) are also available at higher power plant ratings. The safety features, the technical design and the mode of operation are briefly described in the following, taking a power plant with two HTR-Modules for the co-generation of electricity and process steam as an example. Due to its universal applicability and excellent safety features, the modular HTR power plant is suitable for erection on any site, but particularly on sites near other industrial plants or in densely populated areas. The co-generation of electricity and process steam or district heating with a modular HTR power plant as described here is primarily tailored to the requirements of industrial and communal consumers. The site for such a plant is a typical industrial one. The anticipated features of such sites were taken into consideration in the design of the modular HTR power plant

High temperature reactor module power plant. Plant and safety concept June 1986 - 38.07126.2

Energy Technology Data Exchange (ETDEWEB)

NONE

1986-06-15

The modular HTR power plant is a universally applicable energy source for the co-generation of electricity, process steam or district heating. The modular HTR concept is characterized by the fact that standardized reactor units with power ratings of 200 MJ/s (so-called modules) can be combined to form power plants with a higher power rating. Consequently the special safety features of small high-temperature reactors (HTR) are also available at higher power plant ratings. The safety features, the technical design and the mode of operation are briefly described in the following, taking a power plant with two HTR-Modules for the co-generation of electricity and process steam as an example. Due to its universal applicability and excellent safety features, the modular HTR power plant is suitable for erection on any site, but particularly on sites near other industrial plants or in densely populated areas. The co-generation of electricity and process steam or district heating with a modular HTR power plant as described here is primarily tailored to the requirements of industrial and communal consumers. The site for such a plant is a typical industrial one. The anticipated features of such sites were taken into consideration in the design of the modular HTR power plant.

Delayed expression of SAGs correlates with longevity in CMS wheat plants compared to its fertile plants.

Science.gov (United States)

Semwal, Vimal Kumar; Singh, Bhupinder; Khanna-Chopra, Renu

2014-04-01

Reproductive sinks regulate monocarpic senescence in crop plants. Monocarpic senescence was studied in wheat fertile (cv. HW 2041) and its isonuclear cytoplasmic male sterile (CMS) line. CMS plants exhibited slower rate of senescence accompanied by longer green leaf area duration and slower deceleration in chlorophyll, protein content, PN and rubisco content coupled with lower protease activities than fertile (F) plants. CMS plants also exhibited lower ROS levels and less membrane damage than F plants. CMS plants maintained better antioxidant defense, less oxidative damage in chloroplast and higher transcript levels of both rbcL and rbcS genes during senescence than F plants. F plants exhibited early induction and higher expression of SAGs like serine and cysteine proteases, glutamine synthetases GS1 and GS2, WRKY53 transcription factor and decline in transcript levels of CAT1 and CAT2 genes than CMS plants. Hence, using genetically fertile and its CMS line of wheat it is confirmed that delayed senescence in the absence of reproductive sinks is linked with slower protein oxidation, rubisco degradation and delayed activation of SAGs. Better antioxidant defense in chloroplasts at later stages of senescence was able to mitigate the deleterious effects of ROS in CMS plants. We propose that delayed increase in ROS in cytoplasmic male sterile wheat plants resulted in delayed activation of WRKY53, SAGs and the associated biochemical changes than fertile plants.

Plant odour plumes as mediators of plant-insect interactions.

Science.gov (United States)

Beyaert, Ivo; Hilker, Monika

2014-02-01

Insect olfactory orientation along odour plumes has been studied intensively with respect to pheromonal communication, whereas little knowledge is available on how plant odour plumes (POPs) affect olfactory searching by an insect for its host plants. The primary objective of this review is to examine the role of POPs in the attraction of insects. First, we consider parameters of an odour source and the environment which determine the size, shape and structure of an odour plume, and we apply that knowledge to POPs. Second, we compare characteristics of insect pheromonal plumes and POPs. We propose a 'POP concept' for the olfactory orientation of insects to plants. We suggest that: (i) an insect recognises a POP by means of plant volatile components that are encountered in concentrations higher than a threshold detection limit and that occur in a qualitative and quantitative blend indicating a resource; (ii) perception of the fine structure of a POP enables an insect to distinguish a POP from an unspecific odorous background and other interfering plumes; and (iii) an insect can follow several POPs to their sources, and may leave the track of one POP and switch to another one if this conveys a signal with higher reliability or indicates a more suitable resource. The POP concept proposed here may be a useful tool for research in olfactory-mediated plant-insect interactions. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Materials for higher steam temperatures (up to 600 deg C) in biomass and waste fired plant. A review of present knowledge; Material foer hoegre aangtemperaturer (upp till 600 grader C) i bio- och avfallseldade anlaeggningar

Energy Technology Data Exchange (ETDEWEB)

Staalenheim, Annika; Henderson, Pamela

2011-02-15

A goal for the Swedish power industry is to build a demonstration biomass-fired plant with 600 deg C steam data in 2015. Vaermeforsk also has a goal to identify materials that can be used in such a plant. This project involves a survey of present knowledge and published articles concerning materials that are suitable for use in biomass and wastefired plants with steam data up to 600 deg C. The information has been gathered from plants presently in operation, and from field tests previously performed with probes. Plants firing only household waste are excluded. The components considered are waterwalls/furnace walls (affected because of higher steam pressures) and superheaters. Fireside corrosion and steam-side oxidation are dealt with. Candidate materials (or coatings) are suggested and areas for further research have been identified. The purpose of this project is to give state-of-the-art information on what materials could be used in biomass and waste-fired plant to reach a maximum steam temperature of 600 deg C. This report is aimed at suppliers of boilers and materials, energy utility companies and others involved in building new plant with higher steam data. In accordance with the goals of this project: - Materials suitable for use at higher steam temperatures (up to 600 deg C steam) in wood-based biomass and waste-fired plant have been identified. Austenitic stainless steels HR3C, TP 347 HFG and AC66 all have adequate strength, steam-side oxidation and fireside corrosion resistance for use as superheaters. AC66 and HR3C have better steam-side oxidation resistance than TP 347 HFG , but TP 347 HFG has better fireside corrosion resistance. It is recommended that TP 347 HFG be shot-peened on the inside to improve the oxidation resistance if in service with steam temperatures above 580 deg C. - Furnace walls coated with Ni-based alloys or a mixture of Ni- alloy and ceramic show good corrosion resistance at lower temperatures and should be evaluated at higher

Progress and challenges of engineering a biophysical CO2-concentrating mechanism into higher plants.

Science.gov (United States)

Rae, Benjamin D; Long, Benedict M; Förster, Britta; Nguyen, Nghiem D; Velanis, Christos N; Atkinson, Nicky; Hee, Wei Yih; Mukherjee, Bratati; Price, G Dean; McCormick, Alistair J

2017-06-01

Growth and productivity in important crop plants is limited by the inefficiencies of the C3 photosynthetic pathway. Introducing CO2-concentrating mechanisms (CCMs) into C3 plants could overcome these limitations and lead to increased yields. Many unicellular microautotrophs, such as cyanobacteria and green algae, possess highly efficient biophysical CCMs that increase CO2 concentrations around the primary carboxylase enzyme, Rubisco, to enhance CO2 assimilation rates. Algal and cyanobacterial CCMs utilize distinct molecular components, but share several functional commonalities. Here we outline the recent progress and current challenges of engineering biophysical CCMs into C3 plants. We review the predicted requirements for a functional biophysical CCM based on current knowledge of cyanobacterial and algal CCMs, the molecular engineering tools and research pipelines required to translate our theoretical knowledge into practice, and the current challenges to achieving these goals. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Chemical defence and toxins of plants

NARCIS (Netherlands)

Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

2010-01-01

Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens

Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome

DEFF Research Database (Denmark)

Yuan, Wenping; Liu, Shuguang; Dong, Wenjie

2014-01-01

The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP...... that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting...

UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

Directory of Open Access Journals (Sweden)

Paul W. Barnes

2017-08-01

Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

Soil-to-plant transfer factors of natural radionuclides (226Ra and 40K) in selected Thai medicinal plants.

Science.gov (United States)

Saenboonruang, Kiadtisak; Phonchanthuek, Endu; Prasandee, Kamonkhuan

2018-04-01

A soil-to-plant transfer factor (TF) is an important parameter that could be used to estimate radionuclides levels in medicinal plants. This work reports concentrations of natural radionuclides ( 226 Ra and 40 K) and TFs in six Thai medicinal plants grown in central Thailand using an HPGe gamma ray spectrometer. Either root, leaf, or flower parts of each medicinal plant were selected for use in the investigation according to their practical uses in traditional medicine. The results showed that due to K being essential in plants, 40 K had higher arithmetic means of activity concentrations and geometric means of TFs (geometric standard deviations in parentheses) of 610 ± 260 Bq kg -1 dry weight (DW) and 2.0 (1.4), respectively, than 226 Ra, which had the activity concentrations and TFs of 4.8 ± 2.6 Bq kg -1 DW and 0.17 (1.8), respectively. The results also showed that the leaves of medicinal plants had higher activity concentrations and TFs than root and flower parts, probably due to higher metabolic activities in leaves. Furthermore, there was good agreement between the results from the current work and other similar reports on medicinal plants. The information obtained from this work could strengthen knowledge of natural radionuclides in plants and particularly increase available TF data on Thai medicinal plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Higher plant availability and reduced reactor scram frequency in PWRs by appropriate system and I and C design

International Nuclear Information System (INIS)

Frei, G.; Weber, J.

1987-01-01

High plant availability and reliability are guaranteed by appropriate design of reactor and BOP systems, this including the plant I and C systems. It is of advantage to have design, construction and commissioning of the plant concentrated in the hands of a single company to avoid interface problems between the different areas of the plant. The integrated overall control concept developed by KWU with control, limitation and protection systems as well as optimized operational and monitoring systems assisted by instrumentation channel redundance and logic for selection of the second highest (or second lowest) signal value as appropriate for comparison with limitation setpoints, minimize the severity of transients. This results in a reduction in the frequency of reactor scrams and of unnecessary actuation of safety systems. Dynamic plant behavior is described for a number of examples where the improved plant behavior resulting from the above design features enhances plant availability

REPEATABILITY OF THE FRENCH HIGHER VEGETATION TYPES ACCORDING

Directory of Open Access Journals (Sweden)

H. BRISSE

1998-04-01

Full Text Available Higher vegetation types are generally determined by successive approximations and defined by a common consent. Instead, they might be statistically determined and repeated, according to a numerical method called ‘socio-ecology’. This method deals only with floristical data, but gives them an ecological meaning by a previous calibration of the relations between plants, computed as ecological indices. It is applied to a pair of two homologous samples, each having 2.000 relevés and coming from the 60.000 relevés stored in the French data bank ‘Sophy’. Each sample covers the main ecological gradients of the bank, it defines a hierarchy of vegetation types and it explains half the peculiarity of a type with only 10 to 30 discriminant plants, out of the 5.000 plants observed in the relevés. Results : 1 The discriminant plants may characterize the vegetation types, including the higher ones, in a coherent and readable form. 2 In the two independent classifications, having different structures, the same vegetation types are repeated. They are the reciprocal nearest types, in the socio-ecological space. Though the two classifications have no one relevé in common, the repeated types have nearly the same discriminant plants. 3 At the highest level, two clear-cut main types show the difference between light and shadow. The same herbaceous discriminant plants, for a type, and the ligneous or sciaphilous ones, for the other, have similar fidelities and constancies in the two classifications. 4 Such a numerical agreement, instead of common consent, appears again in the sub-types, which remind the classical ones, but which are repeatable.

Evolutionary responses of native plant species to invasive plants: a review.

Science.gov (United States)

Oduor, Ayub M O

2013-12-01

Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

Energy Technology Data Exchange (ETDEWEB)

Ding, S. Y.

2013-01-01

Plant cell walls from maize (Zea mays L.) are imaged using atomic force microscopy (AFM) at the sub-nanometer resolution. We found that the size and shape of fundamental cellulose elementary fibril (CEF) is essentially identical in different cell wall types, i.e., primary wall (PW), parenchyma secondary wall (pSW), and sclerenchyma secondary wall (sSW), which is consistent with previously proposed 36-chain model (Ding et al., 2006, J. Agric. Food Chem.). The arrangement of individual CEFs in these wall types exhibits two orientations. In PW, CEFs are horizontally associated through their hydrophilic faces, and the planar faces are exposed, forming ribbon-like macrofibrils. In pSW and sSW, CEFs are vertically oriented, forming layers, in which hemicelluloses are interacted with the hydrophobic faces of the CEF and serve as spacers between CEFs. Lignification occurs between CEF-hemicelluloses layers in secondary walls. Furthermore, we demonstrated quantitative analysis of plant cell wall accessibility to and digestibility by different cellulase systems at real-time using chemical imaging (e.g., stimulated Raman scattering) and fluorescence microscopy of labeled cellulases (Ding et al., 2012, Science, in press).

Microorganism and filamentous fungi drive evolution of plant synapses.

Science.gov (United States)

Baluška, František; Mancuso, Stefano

2013-01-01

In the course of plant evolution, there is an obvious trend toward an increased complexity of plant bodies, as well as an increased sophistication of plant behavior and communication. Phenotypic plasticity of plants is based on the polar auxin transport machinery that is directly linked with plant sensory systems impinging on plant behavior and adaptive responses. Similar to the emergence and evolution of eukaryotic cells, evolution of land plants was also shaped and driven by infective and symbiotic microorganisms. These microorganisms are the driving force behind the evolution of plant synapses and other neuronal aspects of higher plants; this is especially pronounced in the root apices. Plant synapses allow synaptic cell-cell communication and coordination in plants, as well as sensory-motor integration in root apices searching for water and mineral nutrition. These neuronal aspects of higher plants are closely linked with their unique ability to adapt to environmental changes.

Possibility of Thermomechanical Compressor Application in Desalination Plants

Science.gov (United States)

Blagin, E. V.; Shimanov, A. A.; Uglanov, D. A.; Korneev, S. S.

2018-01-01

This article deals with estimation of thermocompressor operating possibility in desalination plant with mechanical vapour compressor. In this plant thermocompressor is used instead of commonly used centrifugal compressor. Preliminary analysis shows that such plant is able to operate, however, power consumption is 3.5-6.5 higher in comparison with traditional MVC plant. In turn, utilization of thermocompressor allows avoiding usual high-frequency drive of centrifugal compressor. Drives with frequency of 50 Hz are enough for thermocompressor when centrifugal compressor requires drives with frequency up to 500 Hz and higher. Approximate thermocompressor dimensions are estimated.

Utilization of respiratory energy in higher plants : requirements for 'maintenance' and transport processes

NARCIS (Netherlands)

Bouma, T.J.

1995-01-01

Quantitative knowledge of both photosynthesis and respiration is required to understand plant growth and resulting crop yield. However, especially the nature of the energy demanding processes that are dependent on dark respiration in full-grown tissues is largely unknown. The main objective

Experimental mutagenesis in plants

International Nuclear Information System (INIS)

Conger, B.V.

1979-01-01

Considerable progress has been made in directed or controlled mutagenesis with bacterial systems, the genetic resolving power of which is much greater than that of higher plants. The mutagen specificity in higher plants has been of great interest, and numerous results and observations have been reported. The advances in the culture of plant cells and tissues have created much interest concerning the possibility of inducing and recovering mutants at the cellular level. There are great problems including the failure to regenerate plants from cells in all but a few species. The genetic and cytogenetic instability in the culture of plant tissues is well known, and the most common nuclear change is polyploidy including aneuploidy. The degree of polyploidy increases with calluses or culture age. In rice, the frequency of aneuploidy is greater in the calluses derived from roots than those derived from stem internodes. Polyploid and/or self-incompatible plant species are not as amenable to conventional mutation breeding techniques as diploid, self-fertilizing species. Inducing mutations in somatic tissues creates the problem of chimeras. However, the new cultivars of highly heterozygous, outcrossing, self-incompatible species are produced by combining several different clones. The performance of the progeny of at least 4 generations removed from the polycross of the parent clones is the important factor, and a high amount of heterozygocity is tolerated within cultivars and even on the same plants. (Yamashita, S.)

The role of L-DOPA in plants

Science.gov (United States)

Soares, Anderson Ricardo; Marchiosi, Rogério; Siqueira-Soares, Rita de Cássia; Barbosa de Lima, Rogério; Dantas dos Santos, Wanderley; Ferrarese-Filho, Osvaldo

2014-01-01

Since higher plants regularly release organic compounds into the environment, their decay products are often added to the soil matrix and a few have been reported as agents of plant-plant interactions. These compounds, active against higher plants, typically suppress seed germination, cause injury to root growth and other meristems, and inhibit seedling growth. Mucuna pruriens is an example of a successful cover crop with several highly active secondary chemical agents that are produced by its seeds, leaves and roots. The main phytotoxic compound encountered is the non-protein amino acid L-3,4-dihydroxyphenylalanine (L-DOPA), which is used in treating the symptoms of Parkinson disease. In plants, L-DOPA is a precursor of many alkaloids, catecholamines, and melanin and is released from Mucuna into soils, inhibiting the growth of nearby plant species. This review summarizes knowledge regarding L-DOPA in plants, providing a brief overview about its metabolic actions. PMID:24598311

A herbicide-resistant ACCase 1781 Setaria mutant shows higher fitness than wild type.

Science.gov (United States)

Wang, T; Picard, J C; Tian, X; Darmency, H

2010-10-01

It is often alleged that mutations conferring herbicide resistance have a negative impact on plant fitness. A mutant ACCase1781 allele endowing resistance to the sethoxydim herbicide was introgressed from a resistant green foxtail (Setaria viridis (L.) Beauv) population into foxtail millet (S. italica (L.) Beauv.). (1) Better and earlier growth of resistant plants was observed in a greenhouse cabinet. (2) Resistant plants of the advanced BC7 backcross generation showed more vigorous juvenile growth in the field, earlier flowering, more tillers and higher numbers of grains than susceptible plants did, especially when both genotypes were grown in mixture, but their seeds were lighter than susceptible seeds. (3) Field populations originating from segregating hybrids had the expected allele frequencies under normal growth conditions, but showed a genotype shift toward an excess of homozygous resistant plants within 3 years in stressful conditions. Lower seed size, lower germination rate and perhaps unexplored differences in seed longevity and predation could explain how the resistant plants have the same field fitness over the whole life cycle as the susceptible ones although they produce more seeds. More rapid growth kinetics probably accounted for higher fitness of the resistant plants in adverse conditions. The likelihood of a linkage with a beneficial gene is discussed versus the hypothesis of a pleiotropic effect of the ACCase resistance allele. It is suggested that autogamous species like Setaria could not develop a resistant population without the help of a linkage with a gene producing a higher fitness.

Radiochemistry in nuclear power plants

International Nuclear Information System (INIS)

Schwarz, W.

2007-01-01

Radiochemistry is employed in nuclear power plants not as an end in itself but, among other things, as a main prerequisite of optimum radiation protection. Radiochemical monitoring of various loops provides important information about sources of radioactivity, activity distribution in the plant and its changes. In the light of these analytical findings, plant crews are able to take measures having a positive effect on radiation levels in the plant. The example of a BWR plant is used to show, among other things, how radiochemical analyses helped to reduce radiation levels in a plant and, as a consequence, to decrease clearly radiation exposure of the personnel despite higher workloads. (orig.)

Multinationals and plant survival

DEFF Research Database (Denmark)

Bandick, Roger

2010-01-01

The aim of this paper is twofold: first, to investigate how different ownership structures affect plant survival, and second, to analyze how the presence of foreign multinational enterprises (MNEs) affects domestic plants’ survival. Using a unique and detailed data set on the Swedish manufacturing...... sector, I am able to separate plants into those owned by foreign MNEs, domestic MNEs, exporting non-MNEs, and purely domestic firms. In line with previous findings, the result, when conditioned on other factors affecting survival, shows that foreign MNE plants have lower survival rates than non......-MNE plants. However, separating the non-MNEs into exporters and non-exporters, the result shows that foreign MNE plants have higher survival rates than non-exporting non-MNEs, while the survival rates of foreign MNE plants and exporting non-MNE plants do not seem to differ. Moreover, the simple non...

Plants. Ag Ed Environmental Education Series.

Science.gov (United States)

Tulloch, Rodney W.

Designed to serve as a resource tool in a high school vocational agriculture curriculum dealing with the environment as it relates to agriculture, this unit is concerned with plants. Plants are defined and their characteristics described. A section on the effects of environment on higher plants covers temperature, light, water, nutrients, air,…

Advances in genetics. Volume 22: Molecular genetics of plants

International Nuclear Information System (INIS)

Scandalios, J.G.; Caspari, E.W.

1984-01-01

This book contains the following four chapters: Structural Variation in Mitochondrial DNA; The Structure and Expression of Nuclear Genes in Higher Plants; Chromatin Structure and Gene Regulation in Higher Plants; and The Molecular Genetics of Crown Gall Tumorigenesis

Towards Multi Fuel SOFC Plant

DEFF Research Database (Denmark)

Rokni, Masoud; Clausen, Lasse Røngaard; Bang-Møller, Christian

2011-01-01

Complete Solid Oxide Fuel Cell (SOFC) plants fed by several different fuels are suggested and analyzed. The plants sizes are about 10 kW which is suitable for single family house with needs for both electricity and heat. Alternative fuels such as, methanol, DME (Di-Methyl Ether) and ethanol...... are also considered and the results will be compared with the base plant fed by Natural Gas (NG). A single plant design will be suggested that can be fed with methanol, DME and ethanol whenever these fuels are available. It will be shown that the plant fed by ethanol will have slightly higher electrical...

Alpha 1,3-Galactosyltransferase Deficiency in Pigs Increases Sialyltransferase Activities That Potentially Raise Non-Gal Xenoantigenicity

Directory of Open Access Journals (Sweden)

Jong-Yi Park

2011-01-01

Full Text Available We examined whether deficiency of the GGTA1 gene in pigs altered the expression of several glycosyltransferase genes. Real-time RT-PCR and glycosyltransferase activity showed that 2 sialyltransferases [α2,3-sialyltransferase (α2,3ST and α2,6-sialyltransferase (α2,6ST] in the heterozygote GalT KO liver have higher expression levels and activities compared to controls. Enzyme-linked lectin assays indicated that there were also more sialic acid-containing glycoconjugate epitopes in GalT KO livers than in controls. The elevated level of sialic-acid-containing glycoconjugate epitopes was due to the low level of α-Gal in heterozygote GalT KO livers. Furthermore, proteomics analysis showed that heterozygote GalT KO pigs had a higher expression of NAD+-isocitrate dehydrogenase (IDH, which is related to the CMP-N-acetylneuraminic acid hydroxylase (CMAH enzyme reaction. These findings suggest the deficiency of GGTA1 gene in pigs results in increased production of N-glycolylneuraminic acid (Neu5Gc due to an increase of α2,6-sialyltransferase and a CMAH cofactor, NAD+-IDH. This indicates that Neu5Gc may be a critical xenoantigen. The deletion of the CMAH gene in the GalT KO background is expected to further prolong xenograft survival.

Penicillium sp. mitigates Fusarium-induced biotic stress in sesame plants.

Science.gov (United States)

Radhakrishnan, Ramalingam; Pae, Suk-Bok; Shim, Kang-Bo; Baek, In-Youl

2013-07-01

Fusarium-infected sesame plants have significantly higher contents of amino acids (Asp, Thr, Ser, Asn, Glu, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, Lys, His, Try, Arg, and Pro), compared with their respective levels in the healthy control. These higher levels of amino acids induced by Fusarium infection were decreased when Penicillium was co-inoculated with Fusarium. Compared with the control, Fusarium-infected plants showed higher contents of palmitic (8%), stearic (8%), oleic (7%), and linolenic acids (4%), and lower contents of oil (4%) and linoleic acid (11%). Co-inoculation with Penicillium mitigated the Fusarium-induced changes in fatty acids. The total chlorophyll content was lower in Fusarium- and Penicillium-infected plants than in the healthy control. The accumulation of carotenoids and γ-amino butyric acid in Fusarium-infected plants was slightly decreased by co-inoculation with Penicillium. Sesamin and sesamolin contents were higher in Penicillium- and Fusarium- infected plants than in the control. To clarify the mechanism of the biocontrol effect of Penicillium against Fusarium by evaluating changes in primary and secondary metabolite contents in sesame plants.

Wind power plant

Energy Technology Data Exchange (ETDEWEB)

Caneghem, A.E. von

1975-07-24

The invention applies to a wind power plant in which the wind is used to drive windmills. The plant consists basically of a vertical tube with a lateral wind entrance opening with windmill on its lower end. On its upper end, the tube carries a nozzle-like top which increases the wind entering the tube by pressure decrease. The wind is thus made suitable for higher outputs. The invention is illustrated by constructional examples.

Functional plant types drive plant interactions in a Mediterranean mountain range

Directory of Open Access Journals (Sweden)

Petr eMacek

2016-05-01

Full Text Available Shrubs have both positive (facilitation and negative (competition effects on understory plants, the net interaction effect being modulated by abiotic conditions. Overall shrubs influence to great extent the structure of plant communities where they have significant presence. Interactions in a plant community are quite diverse but little is known about their variability and effects at community level. Here we checked the effects of co-occurring shrub species from different functional groups on a focal understory species, determining mechanisms driving interaction outcome, and tested whether effects measured on the focal species were a proxy for effects measured at the community level. Growth, physiological, and reproductive traits of Euphorbia nicaeensis, our focal species, were recorded on individuals growing in association with four dominant shrub species and in adjacent open areas. We also recorded community composition and environmental conditions in each microhabitat.Shrubs provided environmental conditions for plant growth, which contrasted with open areas, including moister soil, greater N content, higher air temperatures, and lower radiation. Shrub-associated individuals showed lower reproductive effort and greater allocation to growth, while most physiological traits remained unaffected. Euphorbia individuals were bigger and had more leaf N under N-fixing than under non-fixing species. Soil moisture was also higher under N-fixing shrubs; therefore soil conditions in the understory may counter reduced light conditions.There was a significant effect of species identity and functional types in the outcome of plant interactions with consistent effects at individual and community levels. The contrasting allocation strategies to reproduction and growth in Euphorbia plants, either associated or not with shrubs, showed high phenotypic plasticity and evidence its ability to cope with contrasting environmental conditions.

Physiological, vascular and nanomechanical assessment of hybrid poplar leaf traits in micropropagated plants and plants propagated from root cuttings: A contribution to breeding programs.

Science.gov (United States)

Ďurkovič, Jaroslav; Husárová, Hana; Javoříková, Lucia; Čaňová, Ingrid; Šuleková, Miriama; Kardošová, Monika; Lukáčik, Ivan; Mamoňová, Miroslava; Lagaňa, Rastislav

2017-09-01

Micropropagated plants experience significant stress from rapid water loss when they are transferred from an in vitro culture to either greenhouse or field conditions. This is caused both by inefficient stomatal control of transpiration and the change to a higher light intensity and lower humidity. Understanding the physiological, vascular and biomechanical processes that allow micropropagated plants to modify their phenotype in response to environmental conditions can help to improve both field performance and plant survival. To identify changes between the hybrid poplar [Populus tremula × (Populus × canescens)] plants propagated from in vitro tissue culture and those from root cuttings, we assessed leaf performance for any differences in leaf growth, photosynthetic and vascular traits, and also nanomechanical properties of the tracheary element cell walls. The micropropagated plants showed significantly higher values for leaf area, leaf length, leaf width and leaf dry mass. The greater leaf area and leaf size dimensions resulted from the higher transpiration rate recorded for this stock type. Also, the micropropagated plants reached higher values for chlorophyll a fluorescence parameters and for the nanomechanical dissipation energy of tracheary element cell walls which may indicate a higher damping capacity within the primary xylem tissue under abiotic stress conditions. The performance of the plants propagated from root cuttings was superior for instantaneous water-use efficiency which signifies a higher acclimation capacity to stressful conditions during a severe drought particularly for this stock type. Similarities were found among the majority of the examined leaf traits for both vegetative plant origins including leaf mass per area, stomatal conductance, net photosynthetic rate, hydraulic axial conductivity, indicators of leaf midrib vascular architecture, as well as for the majority of cell wall nanomechanical traits. This research revealed that

The use of BEACON monitoring in plant power uprates

International Nuclear Information System (INIS)

Miller, Wade

2003-01-01

BEACON is the core support software technology that provides Utilities with continuous 3-D core power distribution monitoring, operational analysis capability, and operations support capability. BEACON monitoring delivers quantifiable plant margins for both reload design and plant operations improvement. When linked to Plant Power Upratings, BEACON permits an improvement in fuel cycle economics through higher peaking factors, higher power levels and higher discharge burnups. Operational flexibility of Uprated Plants is enhanced through elimination of axial power shape and core power tilt specifications. Also, the number of flux maps for these plants is reduced and local power is monitored continuously, permitting faster power escalation. Integrated 3-D power distribution analysis capabilities provide core designers with historical margin data that permits a reduction in core follow requirements as well as reduced curve book data related scope. Examples of specific Uprated Plant applications will be discussed. In anticipation of future needs of Uprated Plants, plans to integrate the technology of BEACON with COLSS are being executed. Finally, the capability to monitor Crud Induced Power Shift (axial offset) is also planned for incorporation into BEACON in the near future and will be discussed

Nutritional and cultural aspects of plant species selection for a controlled ecological life support system

Science.gov (United States)

Hoff, J. E.; Howe, J. M.; Mitchell, C. A.

1982-01-01

The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria.

Transport and compartmentation of phosphite in higher plant cells - kinetic and 31P nuclear magnetic resonance studies

NARCIS (Netherlands)

Danova-Alt, R.; Dijkema, C.; Waard, de P.; Köck, M.

2008-01-01

Phosphite (Phi, H(2)PO(3)(-)), being the active part of several fungicides, has been shown to influence not only the fungal metabolism but also the development of phosphate-deficient plants. However, the mechanism of phosphite effects on plants is still widely unknown. In this paper we analysed

Genetic and epigenetic alterations of the blood group ABO gene in oral squamous cell carcinoma

DEFF Research Database (Denmark)

Gao, Shan; Worm, Jesper; Guldberg, Per

2004-01-01

Loss of histo-blood group A and B antigen expression is a frequent event in oral carcinomas and is associated with decreased activity of glycosyltransferases encoded by the ABO gene. We examined 30 oral squamous cell carcinomas for expression of A and B antigens and glycosyltransferases. We also....... Collectively, we have identified molecular events that may account for loss of A/B antigen expression in 67% of oral squamous cell carcinomas....

Correction: Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

Science.gov (United States)

2014-01-01

Abstract The version of this article published in BMC Genomics 2013, 14: 274, contains 9 unpublished genomes (Botryobasidium botryosum, Gymnopus luxurians, Hypholoma sublateritium, Jaapia argillacea, Hebeloma cylindrosporum, Conidiobolus coronatus, Laccaria amethystina, Paxillus involutus, and P. rubicundulus) downloaded from JGI website. In this correction, we removed these genomes after discussion with editors and data producers whom we should have contacted before downloading these genomes. Removing these data did not alter the principle results and conclusions of our original work. The relevant Figures 1, 2, 3, 4 and 6; and Table 1 have been revised. Additional files 1, 3, 4, and 5 were also revised. We would like to apologize for any confusion or inconvenience this may have caused. Background Fungi produce a variety of carbohydrate activity enzymes (CAZymes) for the degradation of plant polysaccharide materials to facilitate infection and/or gain nutrition. Identifying and comparing CAZymes from fungi with different nutritional modes or infection mechanisms may provide information for better understanding of their life styles and infection models. To date, over hundreds of fungal genomes are publicly available. However, a systematic comparative analysis of fungal CAZymes across the entire fungal kingdom has not been reported. Results In this study, we systemically identified glycoside hydrolases (GHs), polysaccharide lyases (PLs), carbohydrate esterases (CEs), and glycosyltransferases (GTs) as well as carbohydrate-binding modules (CBMs) in the predicted proteomes of 94 representative fungi from Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. Comparative analysis of these CAZymes that play major roles in plant polysaccharide degradation revealed that fungi exhibit tremendous diversity in the number and variety of CAZymes. Among them, some families of GHs and CEs are the most prevalent CAZymes that are distributed in all of the fungi analyzed

Abilities of some higher plants to hydrolyze the acetates of phenols and aromatic-aliphatic alcohols

Directory of Open Access Journals (Sweden)

Agnieszka Mironowicz

2014-01-01

Full Text Available In the biotransformations carried out under the same conditions, the whole intact plants of Spirodela punctata, Nephrolepis exaltata, Cyrtomium falcatum, Nephrolepis cordifolia and the suspension cultures of Helianthus tuberosus, Daucus carota and Petunia hybrida hydrolyze (partially or totally the ester bonds of the acetates of phenols and aromatic-aliphatic alcohols and also the menthyl acetate. Nevertheless, the methyl esters of aromatic acids, structurally similar to the former substrates, do not undergo hydrolysis. At the same time, the viability of first four plants was observed for different levels of acetate concentration. The method of continuous preparative hydrolysis of the same acetates was worked out in Cyrtomium falcatum culture.

Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from 18O incorporation patterns

International Nuclear Information System (INIS)

Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A.

1989-01-01

Previous labeling studies of abscisic acid (ABA) with 18 O 2 have been mainly conducted with water-stressed leaves. In this study, 18 O incorporation into ABA of stressed leaves of various species was compared with 18 O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), 18 O was most abundant in the carboxyl group, whereas incorporation of a second and third 18 O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in 18 O 2 . ABA from turgid bean leaves showed significant 18 O incorporation, again with highest 18 O enrichment in the carboxyl group. On the basis of 18 O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid

Macroecological and macroevolutionary patterns of leaf herbivory across vascular plants.

Science.gov (United States)

Turcotte, Martin M; Davies, T Jonathan; Thomsen, Christina J M; Johnson, Marc T J

2014-07-22

The consumption of plants by animals underlies important evolutionary and ecological processes in nature. Arthropod herbivory evolved approximately 415 Ma and the ensuing coevolution between plants and herbivores is credited with generating much of the macroscopic diversity on the Earth. In contemporary ecosystems, herbivory provides the major conduit of energy from primary producers to consumers. Here, we show that when averaged across all major lineages of vascular plants, herbivores consume 5.3% of the leaf tissue produced annually by plants, whereas previous estimates are up to 3.8× higher. This result suggests that for many plant species, leaf herbivory may play a smaller role in energy and nutrient flow than currently thought. Comparative analyses of a diverse global sample of 1058 species across 2085 populations reveal that models of stabilizing selection best describe rates of leaf consumption, and that rates vary substantially within and among major plant lineages. A key determinant of this variation is plant growth form, where woody plant species experience 64% higher leaf herbivory than non-woody plants. Higher leaf herbivory in woody species supports a key prediction of the plant apparency theory. Our study provides insight into how a long history of coevolution has shaped the ecological and evolutionary relationships between plants and herbivores. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome.

Science.gov (United States)

Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Andrew Black, T; Yan, Wende; Goulden, Mike L; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

2014-06-26

The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.

Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome

Science.gov (United States)

Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Black, T. Andrew; Yan, Wende; Goulden, Michael; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A.; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

2014-01-01

The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.

RNA Editing in Plant Mitochondria

Science.gov (United States)

Hiesel, Rudolf; Wissinger, Bernd; Schuster, Wolfgang; Brennicke, Axel

1989-12-01

Comparative sequence analysis of genomic and complementary DNA clones from several mitochondrial genes in the higher plant Oenothera revealed nucleotide sequence divergences between the genomic and the messenger RNA-derived sequences. These sequence alterations could be most easily explained by specific post-transcriptional nucleotide modifications. Most of the nucleotide exchanges in coding regions lead to altered codons in the mRNA that specify amino acids better conserved in evolution than those encoded by the genomic DNA. Several instances show that the genomic arginine codon CGG is edited in the mRNA to the tryptophan codon TGG in amino acid positions that are highly conserved as tryptophan in the homologous proteins of other species. This editing suggests that the standard genetic code is used in plant mitochondria and resolves the frequent coincidence of CGG codons and tryptophan in different plant species. The apparently frequent and non-species-specific equivalency of CGG and TGG codons in particular suggests that RNA editing is a common feature of all higher plant mitochondria.

Phosphorus deficiency enhances molybdenum uptake by tomato plants

International Nuclear Information System (INIS)

Heuwinkel, H.; Kirkby, E.A.; Le Bot, J.; Marschner, H.

1992-01-01

Water culture experiments are described which provide conclusive evidence that Mo uptake by tomato plants is markedly enhanced by P deficiency. In a longterm experiment, which ran for 11 days, in marked contrast to the uptake of other nutrients, a three fold higher Mo uptake rate was observed after only four days of withdrawal of P from the nutrient medium. In contrast to the gradual increase in pH of the nutrient medium of the plants supplied with P, the pH in the medium of the -P plants fell. Throughout the growth of these plants net H+ efflux could be accounted for by excess cation over anion uptake, indicating that organic acid extrusion plays no major role in the observed fall in pH. Further evidence that Mo uptake is enhanced in P deficient tomato plants is provided in short-term nutrient solution experiments (1h and 4h) using radioactive molybdenum (99Mo). Compared with P sufficient plants, the uptake rates of 99Mo by P deficient plants were three to five times higher after 1h and nine to twelve times higher after 4h. Resupplying P during the uptake periods to deficient plants reduced the uptake rate of 99Mo to values similar to those of P sufficient plants. It is concluded that the uptake of molybdate occurs via phosphate binding/ transporting sites at the plasma membrane of root cells. Further support for this conclusion comes from exchange experiments with non-labelled molybdenum, which show a much larger amount of 99Mo exchangeable from the roots of P deficient plants

Development of uniformly stable isotope labeling system in higher plants for hetero-nuclear NMR experiments in vitro and in vivo

International Nuclear Information System (INIS)

Kikuchi, J.

2005-01-01

Full text: Novel methods for measurement of living systems are making new breakthroughs in life science. In the era of the metabolome (analysis of all measurable metabolites), a MS-based approach is considered to be the major technology, whereas a NMR-based method is recognized as minor technology due to its low sensitivity. Therefore, my laboratory is currently focusing to develop novel methodologies for an NMR-based metabolomics. This will be achieved by uniform stable isotope labeling of higher plants allowing application of multi-dimensional NMR experiments used in protein structure determination. Using these novel methods, I will analyze the dynamic molecular networks inside tissues. Especially, use of stable isotope labeling methods has enormous advantage for discrimination of incorporated or de novo synthesized compounds. Furthermore, potentiality of in vivo-NMR metabolomics will be discussed in the conference. (author)

Effects of combined action of γ-irradiation and sulfur dioxide or N-methyl-N'-nitro-N-nitrosoguanidin on bacteria and higher plants

International Nuclear Information System (INIS)

Kal'chenko, V.A.; Lotareva, O.V.; Spirin, D.A.; Karaban', R.T.; Mal'tseva, L.N.; Ignat'ev, A.A.

1988-01-01

Effect of combined action of of gamma-irradiation and sulfur dioxide or N-methyl-N-nitro-N-nitrosoguanidin on baceria (Bacillus subtilis) and higher plants (Hordeum vulgare L., Pinus sylvestris L.) have been studied. The number of barley germ root cells with chromosomal aberrations depends on the order of treatment with the studied agents. The coefficients of SO 2 and gamma-irradiation correlation fluctuate from 1,3 to 2,6 in the above experiments. In experiments with pine seedlings, these correlation coefficients were similar to additive ones. The data obtained suggest that the pattern of action of the agents is determined by the radiation sensitivity of objects and the order of action of the agents

Cell wall composition and candidate biosynthesis gene expression during rice development

DEFF Research Database (Denmark)

Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra

2016-01-01

Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall...... components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples......, we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had...

Impact of blue, red, and far-red light treatments on gene expression and steviol glycoside accumulation in Stevia rebaudiana.

Science.gov (United States)

Yoneda, Yuki; Nakashima, Hiroshi; Miyasaka, Juro; Ohdoi, Katsuaki; Shimizu, Hiroshi

2017-05-01

Stevia rebaudiana (Bertoni) Bertoni is a plant that biosynthesizes a group of natural sweeteners that are up to approximately 400 times sweeter than sucrose. The sweetening components of S. rebaudiana are steviol glycosides (SGs) that partially share their biosynthesis pathway with gibberellins (GAs). However, the molecular mechanisms through which SGs levels can be improved have not been studied. Therefore, transcription levels of several SG biosynthesis-related genes were analyzed under several light treatments involved in GA biosynthesis. We detected higher transcription of UGT85C2, which is one of the UDP-glycosyltransferases (UGTs) involved in catalyzing the sugar-transfer reaction, under red/far-red (R/FR) 1.22 light-emitting diodes (LEDs) and blue LEDs treatment. In this study, it was demonstrated that transcription levels of SG-related genes and the SGs content are affected by light treatments known to affect the GA contents. It is expected that this approach could serve as a practical way to increase SG contents using specific light treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Philanthropy as a Source to Finance Higher Education. A Synthesis Paper.

Science.gov (United States)

Wurster, Stanley R.

This paper first examines the economics of higher education and the five economic problems that face institutions of higher learning: inflation, expansion of educational services, fluctuating student enrollments, need for an enlarged and modernized capital plant, and uncertain sources of income. The paper then reviews the trends and potential of…

Chemical defence and toxins of plants

OpenAIRE

Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

2010-01-01

Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens play an important role in disease development causing chlorosis, necrosis, or wilting. This chapter mainly focuses on the chemical structures, distribution, and biosynthesis of defense-related natu...

Snf2 family gene distribution in higher plant genomes reveals DRD1 expansion and diversification in the tomato genome.

Science.gov (United States)

Bargsten, Joachim W; Folta, Adam; Mlynárová, Ludmila; Nap, Jan-Peter

2013-01-01

As part of large protein complexes, Snf2 family ATPases are responsible for energy supply during chromatin remodeling, but the precise mechanism of action of many of these proteins is largely unknown. They influence many processes in plants, such as the response to environmental stress. This analysis is the first comprehensive study of Snf2 family ATPases in plants. We here present a comparative analysis of 1159 candidate plant Snf2 genes in 33 complete and annotated plant genomes, including two green algae. The number of Snf2 ATPases shows considerable variation across plant genomes (17-63 genes). The DRD1, Rad5/16 and Snf2 subfamily members occur most often. Detailed analysis of the plant-specific DRD1 subfamily in related plant genomes shows the occurrence of a complex series of evolutionary events. Notably tomato carries unexpected gene expansions of DRD1 gene members. Most of these genes are expressed in tomato, although at low levels and with distinct tissue or organ specificity. In contrast, the Snf2 subfamily genes tend to be expressed constitutively in tomato. The results underpin and extend the Snf2 subfamily classification, which could help to determine the various functional roles of Snf2 ATPases and to target environmental stress tolerance and yield in future breeding.

Modernization of turbines in fossil and nuclear power plants

International Nuclear Information System (INIS)

Harig, T.; Oeynhausen, H.

2004-01-01

Steam turbine power plants have a big share in power generation world-wide. In view of their age structure, they offer the biggest potential for increasing power plant performance, availability and environmental protection. Modernisation and replacement of key components by improved components will reduce fuel consumption and improve power plant performance by higher capacity, higher power, shorter start-up and shutdown times, and reduced standstill times. Modern steam turbine bladings will result in further improvements without additional fuel consumption. (orig.)

Aquatic plant surface as a niche for methanotrophs

Directory of Open Access Journals (Sweden)

Naoko eYoshida

2014-02-01

Full Text Available This study investigated the potential local CH4 sink in various plant parts as a boundary environment of CH4 emission and consumption. By comparing CH4 consumption activities in cultures inoculated with parts from 39 plant species, we observed significantly higher consumption of CH4 associated with aquatic plants than other emergent plant parts such as woody plant leaves, macrophytic marine algae, and sea grass. In situ activity of CH4 consumption by methanotrophs associated with different species of aquatic plants was in the range of 3.7 – 37 μmol⋅h-1⋅g-1 dry weight, which was ca 5.7-370 fold higher than epiphytic CH4 consumption in submerged parts of emergent plants. The qPCR-estimated copy numbers of the particulate methane monooxygenase-encoding gene pmoA were variable among the aquatic plants and ranged in the order of 105 to 107 copies⋅g-1 dry weight, which correlated with the observed CH4 consumption activities. Phylogenetic identification of methanotrophs on aquatic plants based on the pmoA sequence analysis revealed a predominance of diverse gammaproteobacterial type-I methanotrophs, including a phylotype of a possible plant-associated methanotroph with the closest identity (86-89% to Methylocaldum gracile.

Modifying plants for biofuel and biomaterial production.

Science.gov (United States)

Furtado, Agnelo; Lupoi, Jason S; Hoang, Nam V; Healey, Adam; Singh, Seema; Simmons, Blake A; Henry, Robert J

2014-12-01

The productivity of plants as biofuel or biomaterial crops is established by both the yield of plant biomass per unit area of land and the efficiency of conversion of the biomass to biofuel. Higher yielding biofuel crops with increased conversion efficiencies allow production on a smaller land footprint minimizing competition with agriculture for food production and biodiversity conservation. Plants have traditionally been domesticated for food, fibre and feed applications. However, utilization for biofuels may require the breeding of novel phenotypes, or new species entirely. Genomics approaches support genetic selection strategies to deliver significant genetic improvement of plants as sources of biomass for biofuel manufacture. Genetic modification of plants provides a further range of options for improving the composition of biomass and for plant modifications to assist the fabrication of biofuels. The relative carbohydrate and lignin content influences the deconstruction of plant cell walls to biofuels. Key options for facilitating the deconstruction leading to higher monomeric sugar release from plants include increasing cellulose content, reducing cellulose crystallinity, and/or altering the amount or composition of noncellulosic polysaccharides or lignin. Modification of chemical linkages within and between these biomass components may improve the ease of deconstruction. Expression of enzymes in the plant may provide a cost-effective option for biochemical conversion to biofuel. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Use resources of human exometabolites of different oxidation levels for higher plants cultivation on the soil-like substrate as applied to closed ecosystems

Science.gov (United States)

Tikhomirov, Alexander A.; Kudenko, Yurii; Ushakova, Sofya; Tirranen, Lyalya; Gribovskaya, Illiada; Gros, Jean-Bernard; Lasseur, Christophe

The technology of ‘wet incineration' of human exometabolites and inedible plants biomass by means of H2 O2 in alternating electromagnetic field to increase a closure of mass exchange processes in bioregenerative life support systems (BLSS) was developed at the Institute of Biophysics of the Siberian Branch of Russian Academy of Sciences (Krasnoyarsk, Russia). Human exometabolites mineralized can be used in a nutrient solution for plants cultivation in the BLSS phototrophic link. The objective of the given work appears to be the study of use resources of human exometabolites of different oxidation levels processed by the abovementioned method for higher plants cultivation on the soil-like substrate (SLS). The mineralized human wastes were tested for the purpose of their sterility. Then the effect of human exometabolites of different oxidation levels both on wheat productivity and on the SLS microflora composition was examined. The SLS extract with a definite amount of human mineralized wastes was used as an irrigation solution. The conducted experiments demonstrated that the H2 O2 decreasing to 1 ml on 1 g of feces and to 0.25 ml on 1 ml of urine had not affected the sterility of mineralized human wastes. Wheat cultivation on the SLS with the addition in an irrigation solution of mineralized human wastes in the amount simulating 1/6 of a daily human diet showed the absence of basic dependence of plants productivity on oxidation level of human exometabolites. Yet the analysis of the microflora composition of the irrigation solutions demonstrated its dependence on the oxidation level of the exometabolites introduced. The amount of yeast-like fungi increased in 20 times in the solutions containing less oxidized exometabolites in comparison with the variant in which the human wastes were subjected to a full-scale oxidation. Besides, the solutions with less oxidized exometabolites displayed a bigger content of plant pathogenic bacteria and denitrifies. Consequently the

Influence of air pollution on plants

Energy Technology Data Exchange (ETDEWEB)

ten Houten, J G

1967-01-01

The history of plant poisoning from gaseous air pollutants in the Netherlands goes back 60 years; the first incident of this kind was damage caused by fluorine in the vicinity of a superphosphate plant. The effects of hydrogen fluoride, sulfur dioxide, and peroxyacetyl nitrate (PAN) are briefly summarized. Hydrogen fluoride, when present in quantities as low as a few parts per billion, can cause damage to the leaves of plants. Lichens are so sensitive to sulfur dioxide that they cannot exist in the vicinity of large cities and industrial centers where the SO/sub 2/ concentration is higher than .35 parts per billion. PAN, sometimes known as photochemical smog, was considered an American phenomenon until October 1965, when abnormal weather conditions in western Europe caused serious damage from this pollutant to spinach and lettuce. Damage to the leaves of certain species and varieties of plants makes them valuable as indicators, but they are less accurate than chemical analyses, due to the fact that the symptoms are not entirely specific for higher concentrations. The mechanism of plant damage from air pollutants is not completely understood, although it is known for certain that fluorine, ozone, and PAN act at the cellular level, functioning as inhibitors of the plant enzymes. Fluorine also affects the metabolism of carbohydrates.

Variations and determinants of carbon content in plants: a global synthesis

Science.gov (United States)

Ma, Suhui; He, Feng; Tian, Di; Zou, Dongting; Yan, Zhengbing; Yang, Yulong; Zhou, Tiancheng; Huang, Kaiyue; Shen, Haihua; Fang, Jingyun

2018-02-01

Plant carbon (C) content is one of the most important plant traits and is critical to the assessment of global C cycle and ecological stoichiometry; however, the global variations in plant C content remain poorly understood. In this study, we conducted a global analysis of the plant C content by synthesizing data from 4318 species to document specific values and their variation of the C content across plant organs and life forms. Plant organ C contents ranged from 45.0 % in reproductive organs to 47.9 % in stems at global scales, which were significantly lower than the widely employed canonical value of 50 %. Plant C content in leaves (global mean of 46.9 %) was higher than that in roots (45.6 %). Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves, and stems. Plant C content tended to show a decrease with increasing latitude. The life form explained more variation of the C content than climate. Our findings suggest that specific C content values of different organs and life forms developed in our study should be incorporated into the estimations of regional and global vegetation biomass C stocks.

Variations and determinants of carbon content in plants: a global synthesis

Directory of Open Access Journals (Sweden)

S. Ma

2018-02-01

Full Text Available Plant carbon (C content is one of the most important plant traits and is critical to the assessment of global C cycle and ecological stoichiometry; however, the global variations in plant C content remain poorly understood. In this study, we conducted a global analysis of the plant C content by synthesizing data from 4318 species to document specific values and their variation of the C content across plant organs and life forms. Plant organ C contents ranged from 45.0 % in reproductive organs to 47.9 % in stems at global scales, which were significantly lower than the widely employed canonical value of 50 %. Plant C content in leaves (global mean of 46.9 % was higher than that in roots (45.6 %. Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves, and stems. Plant C content tended to show a decrease with increasing latitude. The life form explained more variation of the C content than climate. Our findings suggest that specific C content values of different organs and life forms developed in our study should be incorporated into the estimations of regional and global vegetation biomass C stocks.

Snf2 family gene distribution in higher plant genomes reveals DRD1 expansion and diversification in the tomato genome.

Directory of Open Access Journals (Sweden)

Joachim W Bargsten

Full Text Available As part of large protein complexes, Snf2 family ATPases are responsible for energy supply during chromatin remodeling, but the precise mechanism of action of many of these proteins is largely unknown. They influence many processes in plants, such as the response to environmental stress. This analysis is the first comprehensive study of Snf2 family ATPases in plants. We here present a comparative analysis of 1159 candidate plant Snf2 genes in 33 complete and annotated plant genomes, including two green algae. The number of Snf2 ATPases shows considerable variation across plant genomes (17-63 genes. The DRD1, Rad5/16 and Snf2 subfamily members occur most often. Detailed analysis of the plant-specific DRD1 subfamily in related plant genomes shows the occurrence of a complex series of evolutionary events. Notably tomato carries unexpected gene expansions of DRD1 gene members. Most of these genes are expressed in tomato, although at low levels and with distinct tissue or organ specificity. In contrast, the Snf2 subfamily genes tend to be expressed constitutively in tomato. The results underpin and extend the Snf2 subfamily classification, which could help to determine the various functional roles of Snf2 ATPases and to target environmental stress tolerance and yield in future breeding.

Radionuclide emissions from a coal-fired power plant

International Nuclear Information System (INIS)

Amin, Y.M.; Uddin Khandaker, Mayeen; Shyen, A.K.S.; Mahat, R.H.; Nor, R.M.; Bradley, D.A.

2013-01-01

Current study concerns measurement of radioactivity levels in areas surrounding a 2420 MW thermal power plant fueled predominantly by bituminous coal. The concentrations of 226 Ra, 232 Th and 40 K in onsite bottom-ash were found to be 139 Bq/kg, 108 Bq/kg and 291 Bq/kg, respectively, the levels for these radiolnuclides in soil decreasing with distance from the power plant. At the plant perimeter the respective radionuclide concentrations were 87 Bq/kg, 74 Bq/kg and 297 Bq/kg. In a nearby town, the corresponding concentrations were 104 Bq/kg, 52 Bq/kg and 358 Bq/kg, suggestive of use of TENORM affected soils. The mean radium equivalent activities (Ra eq ) in soil and ash sample in the town were 205 Bq/kg and 316 Bq/kg, respectively. The Kapar plant ash/slag appears to contain a higher level of TENORM than the world average. The degree of contamination is much higher inside the town where slag has been mixed with topsoil as landfill or as simple domestic waste. For the prevailing levels of exposure and a worst case senario, the predicted committed effective dose due to ingestion and inhalation for intake durations of 1- and 30 years would be 4.2 μSv and 220 μSv, respectively. - Highlights: • Detailed studies on naturally occuring radionuclide emissions due to a 2420 MW coal-fired power plant in Malaysia. • Assessment of radiation exposures to the public around the power plant due to an intake of the radionuclides. • The Kapar plant ash/slag appears to contain a higher level of TENORM than the world average. • The degree of contamination is much higher inside the town where slag has been mixed with topsoil as landfill or as simple domestic waste

Symbiotic fungal associations in 'lower' land plants.

Science.gov (United States)

Read, D J; Ducket, J G; Francis, R; Ligron, R; Russell, A

2000-06-29

An analysis of the current state of knowledge of symbiotic fungal associations in 'lower' plants is provided. Three fungal phyla, the Zygomycota, Ascomycota and Basidiomycota, are involved in forming these associations, each producing a distinctive suite of structural features in well-defined groups of 'lower' plants. Among the 'lower' plants only mosses and Equisetum appear to lack one or other of these types of association. The salient features of the symbioses produced by each fungal group are described and the relationships between these associations and those formed by the same or related fungi in 'higher' plants are discussed. Particular consideration is given to the question of the extent to which root fungus associations in 'lower' plants are analogous to 'mycorrhizas' of 'higher' plants and the need for analysis of the functional attributes of these symbioses is stressed. Zygomycetous fungi colonize a wide range of extant lower land plants (hornworts, many hepatics, lycopods, Ophioglossales, Psilotales and Gleicheniaceae), where they often produce structures analogous to those seen in the vesicular-arbuscular (VA) mycorrhizas of higher plants, which are formed by members of the order Glomales. A preponderance of associations of this kind is in accordance with palaeohbotanical and molecular evidence indicating that glomalean fungi produced the archetypal symbioses with the first plants to emerge on to land. It is shown, probably for the first time, that glomalean fungi forming typical VA mycorrhiza with a higher plant (Plantago lanceolata) can colonize a thalloid liverwort (Pellia epiphylla), producing arbuscules and vesicles in the hepatic. The extent to which these associations, which are structurally analogous to mycorrhizas, have similar functions remains to be evaluated. Ascomycetous associations are found in a relatively small number of families of leafy liverworts. The structural features of the fungal colonization of rhizoids and underground axes of

DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

Directory of Open Access Journals (Sweden)

Choudhury Swarup

2010-07-01

Full Text Available Abstract Background The DNA repair and recombination (DRR proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

DNA repair and recombination in higher plants: insights from comparative genomics of Arabidopsis and rice.

Science.gov (United States)

Singh, Sanjay K; Roy, Sujit; Choudhury, Swarup Roy; Sengupta, Dibyendu N

2010-07-21

The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

TOR signalling in plants.

Science.gov (United States)

Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

2015-08-15

Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants. © 2015 Authors; published by Portland Press Limited.

Improved plant nitrogen nutrition contributes to higher water use efficiency in tomatoes under alternate partial root-zone irrigation

DEFF Research Database (Denmark)

Wang, Yaosheng; Liu, Fulai; Andersen, Mathias Neumann

2010-01-01

stomatal conductance during the treatment. At the end of the experiment, N accumulation and 15N recovery was highest in FI, intermediate in PRI and lowest in DI. In addition, PRI plants consistently allocated more N into the upper and middle leaf layers than in the FI and DI treatments. The improved N...... nutrition and distribution in the canopy may indicate that PRI plants have a greater photosynthetic capacity than DI plants; this is confirmed by the observed positive linear relationship between specific leaf N content and δ13C. It is concluded that PRI improves N nutrition and optimises N distribution...

Synthesis and Self-Assembly of Cellulose Microfibrils from Reconstituted Cellulose Synthase.

Science.gov (United States)

Cho, Sung Hyun; Purushotham, Pallinti; Fang, Chao; Maranas, Cassandra; Díaz-Moreno, Sara M; Bulone, Vincent; Zimmer, Jochen; Kumar, Manish; Nixon, B Tracy

2017-09-01

Cellulose, the major component of plant cell walls, can be converted to bioethanol and is thus highly studied. In plants, cellulose is produced by cellulose synthase, a processive family-2 glycosyltransferase. In plant cell walls, individual β-1,4-glucan chains polymerized by CesA are assembled into microfibrils that are frequently bundled into macrofibrils. An in vitro system in which cellulose is synthesized and assembled into fibrils would facilitate detailed study of this process. Here, we report the heterologous expression and partial purification of His-tagged CesA5 from Physcomitrella patens Immunoblot analysis and mass spectrometry confirmed enrichment of PpCesA5. The recombinant protein was functional when reconstituted into liposomes made from yeast total lipid extract. The functional studies included incorporation of radiolabeled Glc, linkage analysis, and imaging of cellulose microfibril formation using transmission electron microscopy. Several microfibrils were observed either inside or on the outer surface of proteoliposomes, and strikingly, several thinner fibrils formed ordered bundles that either covered the surfaces of proteoliposomes or were spawned from liposome surfaces. We also report this arrangement of fibrils made by proteoliposomes bearing CesA8 from hybrid aspen. These observations describe minimal systems of membrane-reconstituted CesAs that polymerize β-1,4-glucan chains that coalesce to form microfibrils and higher-ordered macrofibrils. How these micro- and macrofibrils relate to those found in primary and secondary plant cell walls is uncertain, but their presence enables further study of the mechanisms that govern the formation and assembly of fibrillar cellulosic structures and cell wall composites during or after the polymerization process controlled by CesA proteins. © 2017 American Society of Plant Biologists. All Rights Reserved.

Photoprotection in Plants Optical Screening-based Mechanisms

CERN Document Server

Solovchenko, Alexei

2010-01-01

Optical screening of excessive and potentially harmful solar radiation is an important photoprotective mechanism, though it has received much less attention in comparison with other systems preventing photooxidative damage to photoautotrophic organisms. This photoprotection in the form of screening appears to be especially important for juvenile and senescing plants as well as under environmental stresses—i.e. in situations where the efficiency of enzymatic ROS elimination, DNA repair and other ‘classical’ photoprotective systems could be impaired. This book represents an attempt to develop an integral view of optical screening-based photoprotection in microalgae and higher plants. Towards this end, the key groups of pigments involved in the screening of ultraviolet and visible components of solar radiation in microalgae and higher plants, and the patterns of their accumulation and distribution within plant cells and tissues, are described. Special attention is paid to the manifestations of screening pi...

Radiosensitivity in plants

International Nuclear Information System (INIS)

Nauman, A.F.

1979-01-01

The report presents a compilation of available data on the sensitivity of plants to ionizing radiation, and provides basic information on methods of determining such sensitivities, or of estimating radiosensitivities by calcuation of the nuclear factors upon which they depend. The scope of the data presented here is necessarily limited to the most generally useful radiobiological end points and to the most commonly-used types of radiation. Many of the factors which influence radiosensitivity, particularly nuclear factors, will be discussed. Emphasis will be upon whole-plant studies done at Brookhaven National Laboratory by A.H. Sparrow and his associates, since these studies are the source of most of the available radiosensitivity data and of all the sensitivity predictions listed here. Data presented here include summaries of experimentally-determined radiosensitivities at various end points for both herbaceous and woody higher plants, and for a few species of ferns and lower plants. The algae and fungi have not been considered here due to space limitations

Radiosensitivity in plants

Energy Technology Data Exchange (ETDEWEB)

Nauman, A F

1979-01-01

The report presents a compilation of available data on the sensitivity of plants to ionizing radiation, and provides basic information on methods of determining such sensitivities, or of estimating radiosensitivities by calcuation of the nuclear factors upon which they depend. The scope of the data presented here is necessarily limited to the most generally useful radiobiological end points and to the most commonly-used types of radiation. Many of the factors which influence radiosensitivity, particularly nuclear factors, will be discussed. Emphasis will be upon whole-plant studies done at Brookhaven National Laboratory by A.H. Sparrow and his associates, since these studies are the source of most of the available radiosensitivity data and of all the sensitivity predictions listed here. Data presented here include summaries of experimentally-determined radiosensitivities at various end points for both herbaceous and woody higher plants, and for a few species of ferns and lower plants. The algae and fungi have not been considered here due to space limitations.

Approaches to translational plant science

DEFF Research Database (Denmark)

Dresbøll, Dorte Bodin; Christensen, Brian; Thorup-Kristensen, Kristian

2015-01-01

is lessened. In our opinion, implementation of translational plant science is a necessity in order to solve the agricultural challenges of producing food and materials in the future. We suggest an approach to translational plant science forcing scientists to think beyond their own area and to consider higher......Translational science deals with the dilemma between basic research and the practical application of scientific results. In translational plant science, focus is on the relationship between agricultural crop production and basic science in various research fields, but primarily in the basic plant...... science. Scientific and technological developments have allowed great progress in our understanding of plant genetics and molecular physiology, with potentials for improving agricultural production. However, this development has led to a separation of the laboratory-based research from the crop production...

Conservation of boundary extension mechanisms between plants and animals

OpenAIRE

Mathur, Jaideep

2005-01-01

Locomotion clearly sets plants and animals apart. However, recent studies in higher plants reveal cell-biological and molecular features similar to those observed at the leading edge of animal cells and suggest conservation of boundary extension mechanisms between motile animal cells and nonmotile plant cells.

Microgravity effects on different stages of higher plant life cycle and completion of the seed-to-seed cycle.

Science.gov (United States)

De Micco, V; De Pascale, S; Paradiso, R; Aronne, G

2014-01-01

Human inhabitation of Space requires the efficient realisation of crop cultivation in bioregenerative life-support systems (BLSS). It is well known that plants can grow under Space conditions; however, perturbations of many biological phenomena have been highlighted due to the effect of altered gravity and its possible interactions with other factors. The mechanisms priming plant responses to Space factors, as well as the consequences of such alterations on crop productivity, have not been completely elucidated. These perturbations can occur at different stages of plant life and are potentially responsible for failure of the completion of the seed-to-seed cycle. After brief consideration of the main constraints found in the most recent experiments aiming to produce seeds in Space, we focus on two developmental phases in which the plant life cycle can be interrupted more easily than in others also on Earth. The first regards seedling development and establishment; we discuss reasons for slow development at the seedling stage that often occurs under microgravity conditions and can reduce successful establishment. The second stage comprises gametogenesis and pollination; we focus on male gamete formation, also identifying potential constraints to subsequent fertilisation. We finally highlight how similar alterations at cytological level can not only be common to different processes occurring at different life stages, but can be primed by different stress factors; such alterations can be interpreted within the model of 'stress-induced morphogenic response' (SIMR). We conclude by suggesting that a systematic analysis of all growth and reproductive phases during the plant life cycle is needed to optimise resource use in plant-based BLSS. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Suppression of Plant Defenses by Herbivorous Mites Is Not Associated with Adaptation to Host Plants

Directory of Open Access Journals (Sweden)

Jéssica T. Paulo

2018-06-01

Full Text Available Some herbivores suppress plant defenses, which may be viewed as a result of the coevolutionary arms race between plants and herbivores. However, this ability is usually studied in a one-herbivore-one-plant system, which hampers comparative studies that could corroborate this hypothesis. Here, we extend this paradigm and ask whether the herbivorous spider-mite Tetranychus evansi, which suppresses the jasmonic-acid pathway in tomato plants, is also able to suppress defenses in other host plants at different phylogenetic distances from tomatoes. We test this using different plants from the Solanales order, namely tomato, jimsonweed, tobacco, and morning glory (three Solanaceae and one Convolvulaceae, and bean plants (Fabales. First, we compare the performance of T. evansi to that of the other two most-commonly found species of the same genus, T. urticae and T. ludeni, on several plants. We found that the performance of T. evansi is higher than that of the other species only on tomato plants. We then showed, by measuring trypsin inhibitor activity and life history traits of conspecific mites on either clean or pre-infested plants, that T. evansi can suppress plant defenses on all plants except tobacco. This study suggests that the suppression of plant defenses may occur on host plants other than those to which herbivores are adapted.

Floral advertisement scent in a changing plant-pollinators market.

Science.gov (United States)

Filella, Iolanda; Primante, Clara; Llusià, Joan; Martín González, Ana M; Seco, Roger; Farré-Armengol, Gerard; Rodrigo, Anselm; Bosch, Jordi; Peñuelas, Josep

2013-12-05

Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.

The cognitive and economic value of a nuclear power plant in Korea

Energy Technology Data Exchange (ETDEWEB)

Lim, Gil Hwan [National Assembly Budget Office (NABO), Seoul (Korea, Republic of); Jung, Woo Jin [Information Technology Research Center, Yonsei University, Seoul (Korea, Republic of); Kim, Tae Hwan; Lee, Sang Yong Tom [School of Business, Hanyang University, Seoul (Korea, Republic of)

2017-04-15

We studied the value of a nuclear power plant by considering Koreans' willingness to pay (WTP) for neutralizing the various problems caused by building and operating a new plant. For this, we used a conjoint analysis and ordered logistic regression. We then compared the WTP estimates between various segment groups. The results revealed that each household was willing to pay an additional 99,677 Korean Won (KRW)/mo on average to resolve the negative impacts from a nuclear plant. Therefore, the yearly cognitive and economic value of a nuclear plant in Korea was about 19 trillion KRW. Through a segment analysis, we found that the more educated, younger, and poorer groups gave higher cognitive values than the less educated, older, and richer groups, respectively. Also, people who lived far from a plant gave higher values than people living near a plant, and people with more knowledge about or interest in nuclear energy gave higher values than people with less knowledge or interest. People who felt that nuclear energy is necessary gave higher values to nuclear energy than those who did not. Our results can be used as bases to set targets for promoting nuclear energy and pursuing a national project of building a nuclear power plant.

The cognitive and economic value of a nuclear power plant in Korea

International Nuclear Information System (INIS)

Lim, Gil Hwan; Jung, Woo Jin; Kim, Tae Hwan; Lee, Sang Yong Tom

2017-01-01

We studied the value of a nuclear power plant by considering Koreans' willingness to pay (WTP) for neutralizing the various problems caused by building and operating a new plant. For this, we used a conjoint analysis and ordered logistic regression. We then compared the WTP estimates between various segment groups. The results revealed that each household was willing to pay an additional 99,677 Korean Won (KRW)/mo on average to resolve the negative impacts from a nuclear plant. Therefore, the yearly cognitive and economic value of a nuclear plant in Korea was about 19 trillion KRW. Through a segment analysis, we found that the more educated, younger, and poorer groups gave higher cognitive values than the less educated, older, and richer groups, respectively. Also, people who lived far from a plant gave higher values than people living near a plant, and people with more knowledge about or interest in nuclear energy gave higher values than people with less knowledge or interest. People who felt that nuclear energy is necessary gave higher values to nuclear energy than those who did not. Our results can be used as bases to set targets for promoting nuclear energy and pursuing a national project of building a nuclear power plant

Plant protein and secondary metabolites influence diet selection in a mammalian specialist herbivore

Science.gov (United States)

Ulappa, Amy C.; Kelsey, Rick G.; Frye, Graham G.; Rachlow, Janet L.; Shipley, Lisa A.; Bond, Laura; Pu, Xinzhu; Forbey, Jennifer Sorensen

2015-01-01

For herbivores, nutrient intake is limited by the relatively low nutritional quality of plants and high concentrations of potentially toxic defensive compounds (plant secondary metabolites, PSMs) produced by many plants. In response to phytochemical challenges, some herbivores selectively forage on plants with higher nutrient and lower PSM concentrations relative to other plants. Pygmy rabbits (Brachylagus idahoensis) are dietary specialists that feed on sagebrush (Artemisia spp.) and forage on specific plants more than others within a foraging patch. We predicted that the plants with evidence of heavy foraging (browsed plants) would be of higher dietary quality than plants that were not browsed (unbrowsed). We used model selection to determine which phytochemical variables best explained the difference between browsed and unbrowsed plants. Higher crude protein increased the odds that plants would be browsed by pygmy rabbits and the opposite was the case for certain PSMs. Additionally, because pygmy rabbits can occupy foraging patches (burrows) for consecutive years, their browsing may influence the nutritional and PSM constituents of plants at the burrows. In a post hoc analysis, we did not find a significant relationship between phytochemical concentrations, browse status and burrow occupancy length. We concluded that pygmy rabbits use nutritional and chemical cues while making foraging decisions. PMID:26366011

The xanthophylls in light-harvesting complex II of higher plants: light harvesting and triplet quenching.

NARCIS (Netherlands)

Peterman, E.J.G.; Gradinaru, C.C.; Calkoen, F.; Borst, J.C.; van Grondelle, R.; van Amerongen, H.

1997-01-01

A spectral and functional assignment of the xanthophylls in monomeric and trimeric light-harvesting complex II of green plants has been obtained using HPLC analysis of the pigment composition, laser-flash induced triplet- minus-singlet, fluorescence excitation, and absorption spectra. It is shown

Plants as green phones: Novel insights into plant-mediated communication between below- and above-ground insects.

Science.gov (United States)

Soler, Roxina; Harvey, Jeffrey A; Bezemer, T Martijn; Stuefer, Josef F

2008-08-01

Plants can act as vertical communication channels or 'green phones' linking soil-dwelling insects and insects in the aboveground ecosystem. When root-feeding insects attack a plant, the direct defense system of the shoot is activated, leading to an accumulation of phytotoxins in the leaves. The protection of the plant shoot elicited by root damage can impair the survival, growth and development of aboveground insect herbivores, thereby creating plant-based functional links between soil-dwelling insects and insects that develop in the aboveground ecosystem. The interactions between spatially separated insects below- and aboveground are not restricted to root and foliar plant-feeding insects, but can be extended to higher trophic levels such as insect parasitoids. Here we discuss some implications of plants acting as communication channels or 'green phones' between root and foliar-feeding insects and their parasitoids, focusing on recent findings that plants attacked by root-feeding insects are significantly less attractive for the parasitoids of foliar-feeding insects.

Pathological modifications of plant stem cell destiny

Science.gov (United States)

In higher plants, the shoot apex contains undifferentiated stem cells that give rise to various tissues and organs. The fate of these stem cells determines the pattern of plant growth as well as reproduction; and such fate is genetically preprogrammed. We found that a bacterial infection can derai...

Aspects of neptunium behavior in plants; absorption, distribution, and fate

International Nuclear Information System (INIS)

Cataldo, D.A.; Garland, T.R.; Wildung, R.E.

1984-03-01

The availability of Np(V) for absorption by plants and its subsequent transport and fate are described. Plant uptake of Np from solutions containing 7 x 10 -7 to 473 μg Np/ml is proportional to concentration, exhibiting some saturation at higher concentrations. Soil studies using Np concentrations of 5.2 x 10 -7 to 4.1 μg/g soil show CR values to be constant at approx. 2 at soil concentrations below 4 x 10 -4 μg/g, and increase to 12 at higher soil levels. Soil/plant CR values vary with plant species and range from 0.5 to 4; seed concentrations are a factor of 10 lower than vegetative tissues. Fractionation of plant tissues show Np to be substantially more soluble than Pu, with approx. 50% of the soluble Np being associated with plant ligands of < 5000 MW. 6 references, 5 figures, 1 table

Molecular bases of the ABO blood groups of Indians from the Brazilian Amazon region.

Science.gov (United States)

Franco, R F; Simões, B P; Guerreiro, J F; Santos, S E; Zago, M A

1994-01-01

Phenotype studies of ABO blood groups in most Amerindian populations revealed the exclusive presence of group O. Since group O is the result of the absence of glycosyltransferase activity, its molecular bases may be heterogeneous. We carried out ABO blood group genotyping by analysis of DNA of 30 Indians from 2 Amazonian tribes (Yanomami and Arara), and compared the findings with other populations (Caucasians and Blacks). Two segments of the glycosyltransferase gene were amplified by PCR and digested with KpnI or AluI to detect deletion or base change at positions 258 and 700, respectively. For all subjects, the gene basis of blood group O is the deletion of a single nucleotide at position 258 of the glycosyltransferase A gene, similar to that observed in Caucasoids and Negroids. DNA sequencing of limited regions of the gene supports this conclusion. This finding does not exclude, however, that a heterogeneity of the O allele may be revealed by a more extensive analysis.

Enzymes from Higher Eukaryotes for Industrial Biocatalysis

Directory of Open Access Journals (Sweden)

Zhibin Liu

2004-01-01

Full Text Available The industrial production of fine chemicals, feed and food ingredients, pharmaceuticals, agrochemicals and their respective intermediates relies on an increasing application of biocatalysis, i.e. on enzyme or whole-cell catalyzed conversions of molecules. Simple procedures for discovery, cloning and over-expression as well as fast growth favour fungi, yeasts and especially bacteria as sources of biocatalysts. Higher eukaryotes also harbour an almost unlimited number of potential biocatalysts, although to date the limited supply of enzymes, the high heterogeneity of enzyme preparations and the hazard of infectious contaminants keep some interesting candidates out of reach for industrial bioprocesses. In the past only a few animal and plant enzymes from agricultural waste materials were employed in food processing. The use of bacterial expression strains or non-conventional yeasts for the heterologous production of efficient eukaryotic enzymes can overcome the bottleneck in enzyme supply and provide sufficient amounts of homogenous enzyme preparations for reliable and economically feasible applications at large scale. Ideal enzymatic processes represent an environmentally friendly, »near-to-completion« conversion of (mostly non-natural substrates to pure products. Recent developments demonstrate the commercial feasibility of large-scale biocatalytic processes employing enzymes from higher eukaryotes (e.g. plants, animals and also their usefulness in some small-scale industrial applications.

Heavy metals in reindeer and their forage plants

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O. Eriksson

1990-09-01

Full Text Available An attempt was made to assess the level of heavy metal transfer from forage plants to reindeer (Rangifer tarandus L. in an area in northern Lapland affected from dust from an open pit copper mine. Botanical analyses of rumen contents from reindeer provided information about the main plant species in the diet. Representative plant material was collected from sample plots within an 8 km radius from the central part of the mine and from a reference area situated about 200 km upwind of the mining site. The following plant species were analysed: Bryoria jremontii, Br. juscescens, Cladina rangiferina, Equisetum fluviatile, Descbampsiaflexuosa, Eriopborum vaginatum, Salix glauca, Salix pbylicifolia, Betula nana, and Vaccini-um myrtillus. The greatest difference between metal concentrations in the plants collected from dust contaminated area and from the reference area was found in lichens. Copper is the main metallic component of the ore and was found in higher concentrations in lichens coming from the area around the mine than in lichens from the reference area. Smaller differences were found in vascular plants. Dust particles, remaining on outer surfaces after snow smelt contributed to a limited extent to the metal contents. Species—specific accumulation of metals was observed in some plants. The uptake of lead and cadmium in some vascular plants was somewhat higher in the reference area compared with plants growing in the perifery of the mining center, probably due to the metal concentrations in the bedrock. Organ material (liver and kidney was collected from reindeer in both areas. No noticable effect on metal concentrations in the liver of the reindeer were found. Although the lead, cadmium and copper concentrations were higher in the organs collected from animals in the reference area than in those from the mining area, the levels were still below the concentrations regarded as harmful for the animals from toxicological point of view. The

Subcellular site and nature of intracellular cadmium in plants

International Nuclear Information System (INIS)

Wagner, G.J.

1979-01-01

The mechanisms underlying heavy metal accumulation, toxicity, and tolerance in higher plants are poorly understood. Since subcellular processes are undoubtedly involved in all these phenomena, it is of interest to study the extent, subcellular site and nature of intracellularly accumulated cadmium in higher plants. Whole plants supplied 109 CdCl 2 or 112 CdSO 4 accumulated Cd into roots and aerial tissues. Preparation of protoplasts from aerial tissues followed by subcellular fractionation of the protoplasts to obtain intact vacuoles, chloroplasts and cytosol revealed the presence of Cd in the cytosol but not in vacuoles or chloroplasts. No evidence was obtained for the production of volatile Cd complexes in tobacco

Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

Energy Technology Data Exchange (ETDEWEB)

Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

1989-12-01

Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

The role of silicon in higher plants under salinity and drought stress

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Devrim Coskun

2016-07-01

Full Text Available Although deemed a non-essential mineral nutrient, silicon (Si is clearly beneficial to plant growth and development, particularly under stress conditions, including salinity and drought. Here, we review recent research on the physiological, biochemical, and molecular mechanisms underlying Si-induced alleviation of osmotic and ionic stresses associated with salinity and drought. We distinguish between changes observed in the apoplast (i.e. suberization, lignification, and silicification of the extracellular matrix; transpirational bypass flow of solutes and water, and those of the symplast (i.e. transmembrane transport of solutes and water; gene expression; oxidative stress; metabolism, and discuss these features in the context of Si biogeochemistry and bioavailability in agricultural soils, evaluating the prospect of using Si fertilization to increase crop yield and stress tolerance under salinity and drought conditions.

Diversity of Microbial Carbohydrate-Active enZYmes (CAZYmes) Associated with Freshwater and Soil Samples from Caatinga Biome.

Science.gov (United States)

Andrade, Ana Camila; Fróes, Adriana; Lopes, Fabyano Álvares Cardoso; Thompson, Fabiano L; Krüger, Ricardo Henrique; Dinsdale, Elizabeth; Bruce, Thiago

2017-07-01

Semi-arid and arid areas occupy about 33% of terrestrial ecosystems. However, little information is available about microbial diversity in the semi-arid Caatinga, which represents a unique biome that extends to about 11% of the Brazilian territory and is home to extraordinary diversity and high endemism level of species. In this study, we characterized the diversity of microbial genes associated with biomass conversion (carbohydrate-active enzymes, or so-called CAZYmes) in soil and freshwater of the Caatinga. Our results showed distinct CAZYme profiles in the soil and freshwater samples. Glycoside hydrolases and glycosyltransferases were the most abundant CAZYme families, with glycoside hydrolases more dominant in soil (∼44%) and glycosyltransferases more abundant in freshwater (∼50%). The abundances of individual glycoside hydrolase, glycosyltransferase, and carbohydrate-binding module subfamilies varied widely between soil and water samples. A predominance of glycoside hydrolases was observed in soil, and a higher contribution of enzymes involved in carbohydrate biosynthesis was observed in freshwater. The main taxa associated with the CAZYme sequences were Planctomycetia (relative abundance in soil, 29%) and Alphaproteobacteria (relative abundance in freshwater, 27%). Approximately 5-7% of CAZYme sequences showed low similarity with sequences deposited in non-redundant databases, suggesting putative homologues. Our findings represent a first attempt to describe specific microbial CAZYme profiles for environmental samples. Characterizing these enzyme groups associated with the conversion of carbohydrates in nature will improve our understanding of the significant roles of enzymes in the carbon cycle. We identified a CAZYme signature that can be used to discriminate between soil and freshwater samples, and this signature may be related to the microbial species adapted to the habitat. The data show the potential ecological roles of the CAZYme repertoire and

Effects of herbivory by Diaprepes abbreviatus (Coleoptera: Curculionidae) larvae on four woody ornamental plant species.

Science.gov (United States)

Martin, Cliff G; Mannion, Catharine; Schaffer, Bruce

2009-06-01

The hypothesis that herbivory by Diaprepes root weevil larvae reduces leaf gas exchange and biomass was tested on buttonwood (Conocarpus erectus L.), Surinam cherry (Eugenia uniflora L.), mahogany (Swietenia mahagoni Jacq.), and pond apple (Annona glabra L). For Surinam cherry, net CO2 assimilation, transpiration, and stomatal conductance, but not internal CO2 concentration (collectively referred to as leaf gas exchange values), were 7-32% higher in noninfested than infested plants. For buttonwood, all four gas exchange values were 10-54% higher for noninfested than infested plants 3 h after infestation with large, seventh-instar larvae. However, by 4 wk after this infestation, net CO2 assimilation, transpiration, and stomatal conductance, but not internal CO2 concentration, were 11-37% higher for infested than for noninfested plants. For mahogany and pond apple, there were few or no significant differences in leaf gas exchange values between infested and noninfested plants. For all species, mean shoot and root fresh and dry weights were higher for noninfested than infested plants, with the differences most significant for buttonwood (37-85% higher), followed by Surinam cherry (37-143% higher), mahogany (49-84% higher), and pond apple (24-46% higher), which had no significant differences. There were significant differences among plant species in mean head capsule widths, thus larval instars, of larvae recovered from soil with the largest larvae from Surinam cherry (2.59 +/- 0.19 mm) and the smallest from mahogany (2.29 +/- 0.06 mm). Based on differences in leaf gas exchange and plant biomass between infested and noninfested plants of the four species tested, buttonwood and Surinam cherry are the most vulnerable to feeding by Diaprepes larvae followed by mahogany then pond apple.

Cover plants with potential use for crop-livestock integrated systems in the Cerrado region

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Arminda Moreira de Carvalho

2011-10-01

Full Text Available The objective of this work was to evaluate the effects of lignin, hemicellulose, and cellulose concentrations in the decomposition process of cover plant residues with potential use in no-tillage with corn, for crop-livestock integrated system, in the Cerrado region. The experiment was carried out at Embrapa Cerrados, in Planaltina, DF, Brazil in a split plot experimental design. The plots were represented by the plant species and the subplots by harvesting times, with three replicates. The cover plants Urochloa ruziziensis, Canavalia brasiliensis, Cajanus cajan, Pennisetum glaucum, Mucuna aterrima, Raphanus sativus, Sorghum bicolor were evaluated together with spontaneous plants in the fallow. Cover plants with lower lignin concentrations and, consequently, higher residue decomposition such as C. brasiliensis and U. ruziziensis promoted higher corn yield. High concentrations of lignin inhibit plant residue decomposition and this is favorable for the soil cover. Lower concentrations of lignin result in accelerated plant decomposition, more efficient nutrient cycling, and higher corn yield.

Predominance of self-compatibility in hummingbird-pollinated plants in the Neotropics

Science.gov (United States)

Wolowski, Marina; Saad, Carolina Farias; Ashman, Tia-Lynn; Freitas, Leandro

2013-01-01

Both plant traits and plant-pollinator interactions are thought to influence plant mating systems. For hummingbird-pollinated plants, foraging strategy (territorial or traplining) is also expected to influence plant mating. We hypothesize that the traplining behavior of hermits promotes outcrossing, whereas the behavior of non-hermits favours self-incompatibility. Thus, selection is expected to maintain self-incompatibility in plants pollinated by non-hermits. We explore the incidence of self-incompatibility in Neotropical hummingbird-pollinated plants and its association with hummingbird behavior and plant traits. We conducted a literature review (56 species) and performed hand-pollination experiments in 27 hummingbird-pollinated plants in an Atlantic rainforest. We found that self-incompatibility (measured as hummingbird-pollinated plants. The interaction of hummingbird and habit type affected ISI, as did phylogenetic relationships. Specifically, herbs pollinated by non-hermits had higher ISI than woody plants pollinated by non-hermits, and herbs pollinated by both hermits and non-hermits. For the Atlantic rainforest plant guild, 30 % of the species were self-incompatible. ISI was higher in herbs than in woody species and increased with plant aggregation but was not dependent on foraging behavior, plant density, or floral display. Although hummingbirds differ in their foraging strategies, these behavioral differences seem to have only a minor influence on the incidence of self-incompatibility. Phylogenetic relatedness seems to be the strongest determinant of mating system in Neotropical hummingbird-pollinated plants.

Component design considerations for gas turbine HTGR waste-heat power plant

International Nuclear Information System (INIS)

McDonald, C.F.; Vrable, D.L.

1976-01-01

Component design considerations are described for the ammonia waste-heat power conversion system of a large helium gas-turbine nuclear power plant under development by General Atomic Company. Initial component design work was done for a reference plant with a 3000-MW(t) High-Temperature Gas-Cooled Reactor (HTGR), and this is discussed. Advanced designs now being evaluated include higher core outlet temperature, higher peak system pressures, improved loop configurations, and twin 4000-MW(t) reactor units. Presented are the design considerations of the major components (turbine, condenser, heat input exchanger, and pump) for a supercritical ammonia Rankine waste heat power plant. The combined cycle (nuclear gas turbine and waste-heated plant) has a projected net plant efficiency of over 50 percent. While specifically directed towards a nuclear closed-cycle helium gas-turbine power plant (GT-HTGR), it is postulated that the bottoming waste-heat cycle component design considerations presented could apply to other low-grade-temperature power conversion systems such as geothermal plants

Automated detection and control of volunteer potato plants

NARCIS (Netherlands)

Nieuwenhuizen, A.T.

2009-01-01

High amounts of manual labor are needed to control volunteer potato plants in arable fields. Due to the high costs, this leads to incomplete control of these weed plants, and they spread diseases like Phytophthora infestans to other fields. This results in higher environmental loads by curative

Synthesis and Self-Assembly of Cellulose Microfibrils from Reconstituted Cellulose Synthase1[OPEN

Science.gov (United States)

Purushotham, Pallinti; Fang, Chao; Maranas, Cassandra; Bulone, Vincent

2017-01-01

Cellulose, the major component of plant cell walls, can be converted to bioethanol and is thus highly studied. In plants, cellulose is produced by cellulose synthase, a processive family-2 glycosyltransferase. In plant cell walls, individual β-1,4-glucan chains polymerized by CesA are assembled into microfibrils that are frequently bundled into macrofibrils. An in vitro system in which cellulose is synthesized and assembled into fibrils would facilitate detailed study of this process. Here, we report the heterologous expression and partial purification of His-tagged CesA5 from Physcomitrella patens. Immunoblot analysis and mass spectrometry confirmed enrichment of PpCesA5. The recombinant protein was functional when reconstituted into liposomes made from yeast total lipid extract. The functional studies included incorporation of radiolabeled Glc, linkage analysis, and imaging of cellulose microfibril formation using transmission electron microscopy. Several microfibrils were observed either inside or on the outer surface of proteoliposomes, and strikingly, several thinner fibrils formed ordered bundles that either covered the surfaces of proteoliposomes or were spawned from liposome surfaces. We also report this arrangement of fibrils made by proteoliposomes bearing CesA8 from hybrid aspen. These observations describe minimal systems of membrane-reconstituted CesAs that polymerize β-1,4-glucan chains that coalesce to form microfibrils and higher-ordered macrofibrils. How these micro- and macrofibrils relate to those found in primary and secondary plant cell walls is uncertain, but their presence enables further study of the mechanisms that govern the formation and assembly of fibrillar cellulosic structures and cell wall composites during or after the polymerization process controlled by CesA proteins. PMID:28768815

Soil-plant transfer factors in forest ecosystems

International Nuclear Information System (INIS)

Strebl, F.; Gerzabek, M.H.

1995-04-01

Within scope of an extended study about 137 Cs behaviour in forest ecosystems several parameters were found to influence soil-plant transfer factors. TF-values of different plant species cover a range of two magnitudes. This is partly due to variations in rooting depth of plants and specific physiological adaptations of nutrient supply. Perrenial plants like trees (Picea abies) and dwarf shrubs (Vaccinium myrtillus) showed a distinct age - dependency of 137 Cs - transfer factors. In young plant parts caesium concentration is higher than in old, more signified twigs. A correlation analysis of physico-chemical soil parameters and TF-values to forest vegetation showed, that soil organic matter, especially the degree of humification and the ratio between extractable fulvic to humic acids are important influencing factors of 137 Cs transfer from forest soils to plants. (author)

Pb-H2O Thermogravimetric Plants. The Rankine Cycle

International Nuclear Information System (INIS)

Arosio, S.; Carlevaro, R.

2000-01-01

An economic evaluation concerning Pb-H 2 O thermogravimetric systems with an electric power in the range 200-1.000 kW has been done. Moreover, plant and running costs for a thermogravimetric and a Rankine cycle, 1 MW power, have been compared. Basically due to the lead charge, the plant cost of the former is higher: nevertheless such amount can be recuperated in less than three years, being higher the running cost of the latter [it

Mycorrhizal association between the desert truffle Terfezia boudieri and Helianthemum sessiliflorum alters plant physiology and fitness to arid conditions.

Science.gov (United States)

Turgeman, Tidhar; Ben Asher, Jiftach; Roth-Bejerano, Nurit; Kagan-Zur, Varda; Kapulnik, Yoram; Sitrit, Yaron

2011-10-01

The host plant Helianthemum sessiliflorum was inoculated with the mycorrhizal desert truffle Terfezia boudieri Chatin, and the subsequent effects of the ectomycorrhizal relationship on host physiology were determined. Diurnal measurements revealed that mycorrhizal (M) plants had higher rates of photosynthesis (35%), transpiration (18%), and night respiration (49%) than non-mycorrhizal (NM) plants. Consequently, M plants exhibited higher biomass accumulation, higher shoot-to-root ratios, and improved water use efficiency compared to NM plants. Total chlorophyll content was higher in M plants, and the ratio between chlorophyll a to chlorophyll b was altered in M plants. The increase in chlorophyll b content was significantly higher than the increase in chlorophyll a content (2.58- and 1.52-fold, respectively) compared to control. Calculation of the photosynthetic activation energy indicated lower energy requirements for CO(2) assimilation in M plants than in NM plants (48.62 and 61.56 kJ mol(-1), respectively). Continuous measurements of CO(2) exchange and transpiration in M plants versus NM plants provided a complete picture of the daily physiological differences brought on by the ectomycorrhizal relationships. The enhanced competence of M plants to withstand the harsh environmental conditions of the desert is discussed in view of the mycorrhizal-derived alterations in host physiology. © Springer-Verlag 2011

Alleviatory activities in mycorrhizal tobacco plants subjected to increasing chloride in irrigation water

Directory of Open Access Journals (Sweden)

Ali Reza Safahani Langeroodi

2017-03-01

Full Text Available The effects of presence and absence of arbuscular mycorrhizal (AM+ and AM- fungus (AMF Glomus intraradices on agronomic and chemical characteristics of field-grown tobacco (Nicotiana tabacum L. Virginia type (cv. K-326 plants exposed to varying concentrations of chloride 10, 40, 70 and 100 mg Cl L–1 (C1-C4 were studied over two growing seasons (2012-2013. Mycorrhizal plants had significantly higher uptake of nutrients in shoots and number of leaves regardless of intensities of chloride stress. The cured leaves yields of AM+ plants under C2-C4 chloride stressed conditions were higher than AM- plants. Leaf chloride content increased in line with the increase of chloride level, while AMF colonised plants maintained low Cl content. AM+ plants produced tobacco leaves that contained significantly higher quantities of nicotine than AM- plants. AM inoculation ameliorated the chloride stress to some extent. Antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase as well as non-enzymatic antioxidants (ascorbic acid and glutathione also exhibited great variation with chloride treatment. Chloride stress caused great alterations in the endogenous levels of growth hormones with abscisic acid showing increment. AMF inoculated plants maintained higher levels of growth hormones and also allayed the negative impact of chloride. The level of 40 mg L–1 in combination with arbuscular mycorrhizal can be considered as the acceptable threshold to avoid adverse effects on Virginia tobacco.

Evolutionary plant physiology: Charles Darwin's forgotten synthesis

Science.gov (United States)

Kutschera, Ulrich; Niklas, Karl J.

2009-11-01

Charles Darwin dedicated more than 20 years of his life to a variety of investigations on higher plants (angiosperms). It has been implicitly assumed that these studies in the fields of descriptive botany and experimental plant physiology were carried out to corroborate his principle of descent with modification. However, Darwin’s son Francis, who was a professional plant biologist, pointed out that the interests of his father were both of a physiological and an evolutionary nature. In this article, we describe Darwin’s work on the physiology of higher plants from a modern perspective, with reference to the following topics: circumnutations, tropisms and the endogenous oscillator model; the evolutionary patterns of auxin action; the root-brain hypothesis; phloem structure and photosynthesis research; endosymbioses and growth-promoting bacteria; photomorphogenesis and phenotypic plasticity; basal metabolic rate, the Pfeffer-Kleiber relationship and metabolic optimality theory with respect to adaptive evolution; and developmental constraints versus functional equivalence in relationship to directional natural selection. Based on a review of these various fields of inquiry, we deduce the existence of a Darwinian (evolutionary) approach to plant physiology and define this emerging scientific discipline as the experimental study and theoretical analysis of the functions of green, sessile organisms from a phylogenetic perspective.

Evolutionary plant physiology: Charles Darwin's forgotten synthesis.

Science.gov (United States)

Kutschera, Ulrich; Niklas, Karl J

2009-11-01

Charles Darwin dedicated more than 20 years of his life to a variety of investigations on higher plants (angiosperms). It has been implicitly assumed that these studies in the fields of descriptive botany and experimental plant physiology were carried out to corroborate his principle of descent with modification. However, Darwin's son Francis, who was a professional plant biologist, pointed out that the interests of his father were both of a physiological and an evolutionary nature. In this article, we describe Darwin's work on the physiology of higher plants from a modern perspective, with reference to the following topics: circumnutations, tropisms and the endogenous oscillator model; the evolutionary patterns of auxin action; the root-brain hypothesis; phloem structure and photosynthesis research; endosymbioses and growth-promoting bacteria; photomorphogenesis and phenotypic plasticity; basal metabolic rate, the Pfeffer-Kleiber relationship and metabolic optimality theory with respect to adaptive evolution; and developmental constraints versus functional equivalence in relationship to directional natural selection. Based on a review of these various fields of inquiry, we deduce the existence of a Darwinian (evolutionary) approach to plant physiology and define this emerging scientific discipline as the experimental study and theoretical analysis of the functions of green, sessile organisms from a phylogenetic perspective.

Replacement power costs due to nuclear-plant outages: a higher standard of care

International Nuclear Information System (INIS)

Gransee, M.F.

1982-01-01

This article examines recent state public utility commission cases that deal with the high costs of replacement power that utilities must purchase after a nuclear power plant outage. Although most commissions have approved such expenses, it may be that there is a trend toward splitting the costs of such expenses between ratepayer and stockholder. Commissions are demanding a management prudence test to determine the cause of the outage and whether it meets the reasonable man standard before allowing these costs to be passed along to ratepayers. Unless the standard is applied with flexibility, however, utility companies could invoke the defenses covering traditional common law negligence

The ability to manipulate plant glucosinolates and nutrients explains the better performance of Bemisia tabaci Middle East-Asia Minor 1 than Mediterranean on cabbage plants.

Science.gov (United States)

Cui, Hongying; Guo, Litao; Wang, Shaoli; Xie, Wen; Jiao, Xiaoguo; Wu, Qingjun; Zhang, Youjun

2017-08-01

The performance of herbivorous insects is greatly affected by host chemical defenses and nutritional quality. Some herbivores have developed the ability to manipulate plant defenses via signaling pathways. It is currently unclear, however, whether a herbivore can benefit by simultaneously reducing plant defenses and enhancing plant nutritional quality. Here, we show that the better performance of the whitefly Bemisia tabaci Middle East-Asia Minor 1 (MEAM1; formerly the "B" biotype) than Mediterranean (MED; formerly the "Q" biotype) on cabbage is associated with a suppression of glucosinolate (GS) content and an increase in amino acid supply in MEAM1-infested cabbage compared with MED-infested cabbage. MEAM1 had higher survival, higher fecundity, higher intrinsic rate of increase ( r m ), a longer life span, and a shorter developmental time than MED on cabbage plants. Amino acid content was higher in cabbage infested with MEAM1 than MED. Although infestation by either biotype decreased the levels of total GS, aliphatic GS, glucoiberin, sinigrin, glucobrassicin, and 4OH-glucobrassicin, and the expression of related genes in cabbage, MED infestation increased the levels of 4ME-glucobrassicin, neoglucobrassicin, progoitrin, and glucoraphanin. The GS content and expression of GS-related genes were higher in cabbage infested with MED than with MEAM1. Our results suggest that MEAM1 performs better than MED on cabbage by manipulating host defenses and nutritional quality.

A DUF-246 family glycosyltransferase-like gene affects male fertility and the biosynthesis of pectic arabinogalactans

DEFF Research Database (Denmark)

Stonebloom, Solomon; Ebert, Berit; Xiong, Guangyan

2016-01-01

rates of pollen tube formation in pollen from pagr heterozygotes. To characterize a loss-of-function phenotype for PAGR, the Nicotiana benthamiana orthologs, NbPAGR-A and B, were transiently silenced using Virus Induced Gene Silencing. NbPAGR-silenced plants exhibited reduced internode and petiole...

Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

CSIR Research Space (South Africa)

Thwala, Melusi

2012-09-01

Full Text Available during the 14-d exposure. The biochemical anti-oxidative status of the plant specimens were investigated using quantitative analysis of total antioxidant capacity, peroxidase and activity of catalase and superoxide dismutase. The anti-oxidative defence...

Physiological conjunction of allelochemicals and desert plants.

Science.gov (United States)

Yosef Friedjung, Avital; Choudhary, Sikander Pal; Dudai, Nativ; Rachmilevitch, Shimon

2013-01-01

Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds) were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

Physiological conjunction of allelochemicals and desert plants.

Directory of Open Access Journals (Sweden)

Avital Yosef Friedjung

Full Text Available Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

Comparative Analysis of Power Plant Options for Enhanced Geothermal Systems (EGS

Directory of Open Access Journals (Sweden)

Mengying Li

2014-12-01

Full Text Available Enhanced geothermal systems (EGS extract heat from underground hot dry rock (HDR by first fracturing the HDR and then circulating a geofluid (typically water into it and bringing the heated geofluid to a power plant to generate electricity. This study focuses on analysis, examination, and comparison of leading geothermal power plant configurations with a geofluid temperature from 200 to 800 °C, and also analyzes the embodied energy of EGS surface power plants. The power generation analysis is focused on flash type cycles for using subcritical geofluid (<374 °C and expansion type cycles for using supercritical geofluid (>374 °C. Key findings of this study include: (i double-flash plants have 24.3%–29.0% higher geofluid effectiveness than single-flash ones, and 3%–10% lower specific embodied energy; (ii the expansion type plants have geofluid effectiveness > 750 kJ/kg, significantly higher than flash type plants (geofluid effectiveness < 300 kJ/kg and the specific embodied energy is lower; (iii to increase the turbine outlet vapor fraction from 0.75 to 0.90, we include superheating by geofluid but that reduces the geofluid effectiveness by 28.3%; (iv for geofluid temperatures above 650 °C, double-expansion plants have a 2% higher geofluid effectiveness and 5%–8% lower specific embodied energy than single-expansion ones.

In situ DNA-RNA hybridization using in vitro 125I-labeled ribosomal RNA of higher plant

International Nuclear Information System (INIS)

Sato, Seiichi; Kikuchi, Tadatoshi; Ishida, M.R.; Tanaka, Ryuso.

1975-01-01

In situ hybridization using 125 I-labeled ribosomal RNA was applied to plant cells. Cytoplasmic 25 s rRNA, which was eluted from acrylamide gels after electrophoretic separation, was labeled in vitro with carrier-free 125 I and hybridized with the interphase nuclei in root tips of Vicia faba. In most of the preparations, the nucleoli were more heavily labeled than the other regions within nuclei, and several types of grain distribution were observed on the nucleoli. From these results, it was confirmed that in situ hybridization using 125 I-labeled rRNA can be used very effectively to detect the annealing sites of different molecular species of rRNA within the nuclei of plant cells, for which it is not as easy to obtain high specific radioactive rRNA in vivo as it is in the case of cultured animal cells. (auth.)

Effects of host-plant population size and plant sex on a specialist leaf-miner

DEFF Research Database (Denmark)

Bañuelos, María-José; Kollmann, Johannes Christian

2011-01-01

of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different...... punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively...... stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size...

DMSP: Occurrence in plants and response to salinity in Zea mays

NARCIS (Netherlands)

Ausma, T.; Kebert, M.; Stefels, J.; De Kok, L.J.; De Kok, L.J.; Hawkesford, M.J.; Haneklaus, S.H.; Schnug, E.

2017-01-01

Dimethylsulfoniopropionate (DMSP) is a secondary sulfur compound that is present in high levels in several marine algal species and some higher plant species. DMSP has also been detected in low levels in some other plant species, though its overall occurrence within the plant kingdom remains

Chromosomal mutation by fission neutrons and X-rays in higher plants. A review on results of the joint research program utilizing Kinki University reactor

International Nuclear Information System (INIS)

Yonezawa, Yoshihiko

2010-01-01

We have studied the efficiency of fission neutrons from the nuclear reactor of Kinki University (UTR-KINKI) and X-rays to chromosomes of higher plants for over 20 years. In this review, we described the development of bio-dosimeter using hyper-sensibility of germinating onion roots for irradiation, the analysis of chromosome structure in Haplopappus gracilis (Asteraceae), with the special reference of latent centromeres and survived telomeres throughout chromosomal evolution, the experimental studies on the induction of chromosomal rearrangement in Zebrina pendula (Commelinaceae), the behavior of chromosome fragments with non-localized centromeres in Carex and Eleocharis (Cyperaceae), and the possibility as a bio-dosimeter of pollen mother cells of Tradescantia paludosa (Commelinaceae) for the detection of low-dose radiation. (author)

Are Wave and Tidal Energy Plants New Green Technologies?

Science.gov (United States)

Douziech, Mélanie; Hellweg, Stefanie; Verones, Francesca

2016-07-19

Wave and tidal energy plants are upcoming, potentially green technologies. This study aims at quantifying their various potential environmental impacts. Three tidal stream devices, one tidal range plant and one wave energy harnessing device are analyzed over their entire life cycles, using the ReCiPe 2008 methodology at midpoint level. The impacts of the tidal range plant were on average 1.6 times higher than the ones of hydro-power plants (without considering natural land transformation). A similar ratio was found when comparing the results of the three tidal stream devices to offshore wind power plants (without considering water depletion). The wave energy harnessing device had on average 3.5 times higher impacts than offshore wind power. On the contrary, the considered plants have on average 8 (wave energy) to 20 (tidal stream), or even 115 times (tidal range) lower impact than electricity generated from coal power. Further, testing the sensitivity of the results highlighted the advantage of long lifetimes and small material requirements. Overall, this study supports the potential of wave and tidal energy plants as alternative green technologies. However, potential unknown effects, such as the impact of turbulence or noise on marine ecosystems, should be further explored in future research.

Effects of Soil Quality Enhancement on Pollinator-Plant Interactions

Directory of Open Access Journals (Sweden)

Yasmin J. Cardoza

2012-01-01

Full Text Available Both biotic and abiotic factors can affect soil quality, which can significantly impact plant growth, productivity, and resistance to pests. However, the effects of soil quality on the interactions of plants with beneficial arthropods, such as pollinators, have not been extensively examined. We studied the effects of vermicompost (earthworm compost, VC soil amendment on behavioral and physiological responses of pollinators to flowers and floral resources, using cucumbers, Cucumis sativus, as our model system. Results from experiments conducted over three field seasons demonstrated that, in at least two out of three years, VC amendment significantly increased visit length, while reducing the time to first discovery. Bumblebee (Bombus impatiens workers that fed on flowers from VC-amended plants had significantly larger and more active ovaries, a measure of nutritional quality. Pollen fractions of flowers from VC-grown plants had higher protein compared to those of plants grown in chemically fertilized potting soil. Nectar sugar content also tended to be higher in flowers from VC-grown plants, but differences were not statistically significant. In conclusion, soil quality enhancement, as achieved with VC amendment in this study, can significantly affect plant-pollinator interactions and directly influences pollinator nutrition and overall performance.

Contrasting effects of land use intensity and exotic host plants on the specialization of interactions in plant-herbivore networks.

Science.gov (United States)

de Araújo, Walter Santos; Vieira, Marcos Costa; Lewinsohn, Thomas M; Almeida-Neto, Mário

2015-01-01

Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones.

Mineral composition of plants of family zygophyllaceae and euphorbiaceae

International Nuclear Information System (INIS)

Dastagir, G.; Hussain, F.

2014-01-01

In the present study with few exceptions, most of the minerals concentrations were higher in winter than in summer in all the investigated plants of family Zygophyllaceae and Euphorbiaceae. Calcium content in Fagonia cretica, Peganum harmala and Chrozophora tinctoria was significantly higher in winter than summer while in Tribulus terrestris and Ricinus communis it was significantly lower in winter. Potassium significantly increased in winter compared to summer in all the tested plants. Sodium in winter significantly differed in all the tested plants. Copper increased insignificantly in winter than summer in all plants. Mn also increased in winter as compared to summer in all the plants. The Mo was less in winter in F. cretica and T. terrestris while it increased in P. harmala, C. tinctoria and R. communis during winter and all plants means showed that they were significantly different from each other. Zinc was poor in winter than summer in F. cretica, P. harmala and T. terrestris, and it increased in C. tinctoria and R. communis. Aluminum was less in winter in F. cretica, P. harmala and R. communis which increased in T. terrestris and C. tinctoria winter. (author)

Antithrombin activity of medicinal plants of the Azores.

Science.gov (United States)

de Medeiros, J M; Macedo, M; Contancia, J P; Nguyen, C; Cunningham, G; Miles, D H

2000-09-01

A chromogenic bioassay was utilized to determine the antithrombin activity of methylene chloride and methanol extracts prepared from 50 plants of Azores. Extracts of the six plants Hedychium gardneranum, Tropaeolum majus, Gunnera tinctoria, Hedera helix, Festuca jubata and Laurus azorica demonstrated activity of 78% or higher in this bioassay system.

Combining polysaccharide biosynthesis and transport in a single enzyme: dual-function cell wall glycan synthases.

Directory of Open Access Journals (Sweden)

Jonathan Kent Davis

2012-06-01

Full Text Available Extracellular polysaccharides are synthesized by a wide variety of species, from unicellular bacteria and Archaea to the largest multicellular plants and animals in the biosphere. In every case, the biosynthesis of these polymers requires transport across a membrane, from the cytosol to either the lumen of secretory pathway organelles or directly into the extracellular space. Although some polysaccharide biosynthetic substrates are moved across the membrane to sites of polysaccharide synthesis by separate transporter proteins before being incorporated into polymers by glycosyltransferase proteins, many polysaccharide biosynthetic enzymes appear to have both transporter and transferase activities. In these cases, the biosynthetic enzymes utilize substrate on one side of the membrane and deposit the polymer product on the other side. This review discusses structural characteristics of plant cell wall glycan synthases that couple synthesis with transport, drawing on what is known about such dual-function enzymes in other species.

Development of a Competent and Trouble Free DNA Isolation Protocol for Downstream Genetic Analyses in Glycine Species

Directory of Open Access Journals (Sweden)

Muhammad Amjad Nawaz

2016-08-01

Full Text Available Extraction of deoxyribose nucleic acid (DNA from plants is preliminary step in molecular biology. Fast and cost effective genomic DNA isolation from Glycine species for downstream application is a major bottleneck. Here we report a high throughput and trouble free method for genomic DNA extraction from leaf and seeds of Glycine species with high quality and quantity. Protocol reports the optimization by employing different concentrations of CTAB and PVP in extraction buffer. Efficiency of optimized protocol was compared with frequently used DNA extraction methods. Wide adoptability and utility of this protocol was confirmed by DNA extraction from leaves as well as seeds of G. max, G. soja, G. tomentella and G. latifolia. Extracted DNA was successfully subjected to PCR amplification of five microsatellite markers and four putative glycosyltransferase genes. DNA extraction protocol is reproducible, trouble free, rapid and can be adopted for plant molecular biology applications.

The effect of plant population and nitrogen fertilizer on

Directory of Open Access Journals (Sweden)

mohamad reza asgaripor

2009-06-01

Full Text Available Interest has increased towards hemp (Cannabis sativa L. fibre production due to renewed demand for natural fibre in the world. A Study was conducted in 2005 at Shirvan in Northern Khorasan province, Iran, to determine the effects of three plant populations (30, 90 and 150 plant per m2 and three rates of nitrogen application (50, 150 and 250 kg N per ha on final stand, stalk height, basal stalk diameter, total stalk yield as well as fibre content from stalk and fibre yield in male and female plants. A split plot experimental with three replications was used. The result indicated that due to enhanced competition for light at higher population on density and N2 level plant mortality was higher than other treatment Morphological characteristics were highly correlated with plant sexual, plant population and nitrogen fertilizer. Highest stem, leaf and inflorescence yield were obtained at 250 plant m-2 when 150 kg N ha-1 was used. Lowest plant density did not show self-thinning but reduced above ground dry matter. Shoot dry matter increased with increasing plant density and nitrogen supply. Apparently, fibre content was greater at medium density and lowest nitrogen fertilizer, however, fibre yield was greatest at highest plant population and nitrogen fertilizer. In terms of fibre yield, approximate 31.7% of the fibre was located in the bottom parts, 22.4% in the middle and only 9.9% in the top part of the stem. The results suggest that hemp can yield large quantities of useful fibre at Shirvan when planted in proper plant densities and suitable nitrogen fertilizer.

East-Asia nuclear/fossil power plant competitiveness

International Nuclear Information System (INIS)

Braun, Ch.

1996-01-01

The competitiveness of a new nuclear plant vs. a new oil or gas fired combined cycle plant or a coal fired plant in East-Asia, is reviewed in the paper. Both the nuclear and the fossil fired plants are evaluated as either utility financed or independent power producer (IPP) financed. Two types of advanced light water reactors (ALWRs) are considered in this paper, namely evolutionary ALWRs (1200 MWe size) and passive ALWRs (600 MWe class). A range of capital and total generation costs for each plant type is reported here. The comparison centers on three elements of overall competitiveness: generation costs, hard currency requirements, and employment requirements. Each of these aspects is considered perspective. Year-by-Year generation cost history over the plant lifetime is shown in some cases. It is found here that a utility financed evolutionary and passive ALWRs are broadly competitive with an IPP financed gas fired combined cycle plant and are more economic than oil fired combined cycle or a coal fired plant. A single unit evolutionary ALWR may have a 12 - 15 % capital cost advantage over a single passive ALWR then adjusted on a per KWe basis. Front-end hard currency requirements of a passive ALWR are 2.5 times higher than for a combined plant and evolutionary ALWRs requires 3.6 times higher up-front cost. However, on a lifetime basis, passive ALWR net hard currency requirements are two times lower than for a combined cycle plant. Evolutionary ALWR net hard currency requirements are three times over than those of a combined cycle plant. The effects of domestic vs. world price of fossil fuels on relative nuclear competitiveness are reviewed in this nuclear competitiveness paper. Employment requirements in an ALWR during both the construction period and lifetime operation, exceed the requirements for oil or gas fired plants by a factor of five. While contributing to overall plant cost, employment requirements can also be viewed as opportunity to increase national

In silico identification and analysis of phytoene synthase genes in plants.

Science.gov (United States)

Han, Y; Zheng, Q S; Wei, Y P; Chen, J; Liu, R; Wan, H J

2015-08-14

In this study, we examined phytoene synthetase (PSY), the first key limiting enzyme in the synthesis of carotenoids and catalyzing the formation of geranylgeranyl pyrophosphate in terpenoid biosynthesis. We used known amino acid sequences of the PSY gene in tomato plants to conduct a genome-wide search and identify putative candidates in 34 sequenced plants. A total of 101 homologous genes were identified. Phylogenetic analysis revealed that PSY evolved independently in algae as well as monocotyledonous and dicotyledonous plants. Our results showed that the amino acid structures exhibited 5 motifs (motifs 1 to 5) in algae and those in higher plants were highly conserved. The PSY gene structures showed that the number of intron in algae varied widely, while the number of introns in higher plants was 4 to 5. Identification of PSY genes in plants and the analysis of the gene structure may provide a theoretical basis for studying evolutionary relationships in future analyses.

Radioactive properties of medicinal plants

International Nuclear Information System (INIS)

Ahmedova, G.A.

2003-01-01

Full text: A complicated cycle of various compounds' synthesis is provided by plants in the process of their development. The synthesized compounds are necessary to maintain the life of all living organisms both in water and on the land. Together with the organic compounds all known natural radionuclides are accumulated by the plants. Many plants possess the ability to accumulate some elements, whose concentration in the plants may be much higher than that in the soils and water sources. It is well known that the plants are basic or initial raw materials for producing numerous food products, as well as medicinal preparations. The radionuclides, accumulated in the plants, may pass to the human organism through the products and drugs, and may become a source of internal radiation. Accumulation of the radionuclides in various human organs above the maximal acceptable concentration (MAC) may lead to various pathologic changes. That is why it is a necessary and urgent problem to carry out investigations of the radioactive properties of the plants (i.e. to determine their radioecological cleanliness) before using the medicinal plant for pharmacological purposes. In the present work we investigated the radioactive processes of kinds of medicinal plants by the method of semi-conductor gamma-spectrometry. Measurements of the gamma-spectra of the plants' leach were carried out with the help of a gamma-spectrometer with a Ge(Li) detector accompanied by a 4096-channel analyzer. Responsive volume of the detector was 40 cm 3 , energy resolution with respect to 1333 keV 60 Co line was 3 keV. In the measured spectra we observed clearly photo-peaks belonging to uranium-238 family: 186 keV 226 Ra; 295, 351 keV 214 Pb; 609, 1120, 1764 keV 214 Bi; and those belonging to thorium - 232 family: 339, 911, 968 keV 2 28 Ac; 583, 2614 keV 208 Te; as well as the photo-peak of the natural radionuclide 40 K with the energy 1460 keV. From the proper gamma-lines, observed in the spectra, we

Establishment of a high-efficiency plant regeneration and ...

African Journals Online (AJOL)

STORAGESEVER

2009-10-05

Oct 5, 2009 ... presented higher CIP, EIP and plant regeneration percentage (PRP) than others; the four materials, including Huangzao4, Huangye4, Jing24 and Ji853 from Tangsipingtou group, were not easy to be differentiated into plants, in spite of high CIP. Maize inbred line 18-599(red) as a representative was.

Traditional medicinal plants in Nigeria--remedies or risks.

Science.gov (United States)

Awodele, O; Popoola, T D; Amadi, K C; Coker, H A B; Akintonwa, A

2013-11-25

Soil pollution due to increasing industrialization is a reality that is taking its toll on mankind today. Considering the population of people that use herbal remedies especially in developing countries and the discharge of industrial waste on surrounding herbal vegetation, it is imperative to determine the heavy metals contamination in some commonly used medicinal plants. Representative samples of five medicinal plants Ageratum conyzoides, Aspilia africana, Alchornea cordifolia, Amaranthus brasiliensis and Chromolaena odorata were collected from Ikpoba-Okha L.G.A, Edo State Nigeria, around a paint company and another set of same plants were collected from a non-polluted source. Dried leaves and roots of collected plants were digested and analyzed using Atomic Absorption Spectrophotometer (AAS) for the presence of Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni) and Zinc (Zn). Soil samples from polluted and non-polluted areas were also analyzed to ascertain the levels of these heavy metals in the environment. Results show that the concentrations of these heavy metals in the leaves and roots of plants collected from polluted soil were significantly higher than those obtained from unpolluted soil. Correspondingly heavy metal concentrations were significantly higher in polluted than in unpolluted soil samples. As part of continuing effort in the standardization of traditional remedies, environmental contamination control and abatement is evident. The source of medicinal plants/herbs should also be a cause for concern since the toxicity of medicinal plants is sometimes associated with environmental sources of the plants. © 2013 Elsevier Ireland Ltd. All rights reserved.

Climate impacts on bird and plant communities from altered animal-plant interactions

Science.gov (United States)

Martin, Thomas E.; Maron, John L.

2012-01-01

The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

Mode of action of plant defensins suggests therapeutic potential

NARCIS (Netherlands)

Thomma, B.P.H.J.; Cammue, B.P.A.; Thevissen, K.

2003-01-01

Higher vertebrates can rely both on an innate as well as an adaptive immune system for defense against invading pathogens. In contrast, plants can only employ an innate immune system that largely depends on the production of antimicrobial compounds such as plant defensins and other

Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

CSIR Research Space (South Africa)

Thwala, Melusi

2012-09-01

Full Text Available The authors present evidence of free radical activity and resultant anti-oxidative defence in Spirodela plants after exposure to 0.01-1000 mg/L of ZnO and Ag nanoparticles (NPs) over 96-h and 14-d. The quantification of reactive nitrogen...

Radioactive emission from thermal power plants

Energy Technology Data Exchange (ETDEWEB)

Okamoto, K [New South Wales Univ., Kensington (Australia). Dept. of Applied Mathematics

1981-07-01

Radioactive hazards of the emissions and wastes of thermal power plants arising from fuel impurities of uranium and thorium are discussed. The hazard due to radioactive emission is calculated for an average Australian bituminous coal which contains 2 ppm of U and 2.7 ppm of Th. When the dust removal efficiency of a coal-fired power plant is 99%, the radioactive hazard is greater than that of a nuclear reactor of the same electrical output. After 500 years the radioactive toxicity of the coal waste will be higher than that of fission products of a nuclear reactor and after 2,000 years it will exceed the toxicity of all the nuclear wastes including actinides. The results of a recent calculation are shown, according to which the radioactive hazard of a coal-fired power plant to the public is from several hundred to several tens of thousands of times higher than that of a total fuel cycle of plutonium. It is found that in some regions, such as Japan, the hazard due to /sup 210/Po through seafood could be considerable.

Economic evaluation of the integrated SMART desalination plant

International Nuclear Information System (INIS)

Hwang, Young Dong; Lee, Man Kye; Yeo, Ji Won; Kim, Hee Chul; Chang, Moon Hee

2001-04-01

In this study, an economic evaluation methodology of the integrated SMART desalination plant was established and the economic evaluation of SMART was performed. The plant economics was evaluated with electricity generation costs calculated using approximate estimates of SMART cost data and the result was compared with the result calculated using the SMART design data and estimated bulk materials. In addition, a series of sensitivity studies on the power generation cost was performed for the main economic parameters of SMART Power credit method was used for the economic analysis of the integrated SMART desalination plant. Power credit method is a widely used economic analysis method for the cogeneration plant when the major portion of the energy is used for the electricity generation. In the case of using SMART fot power generation only, the result shows that the electricity generation cost of SMART is higher than that of the alternative power options. However, it can be competitive with the other power options in the limited cases, especially with the gas fired combined plant. In addition, an economic analysis of the integrated SMART desalination plant coupled with MED was performed. The calculated water production cost is in the range of 0.56 approx. 0.88($/m 3 ) for the plant availability of 80% or higher, which is close to the study results presented by the various other countries. This indicates that SMART can be considered as a competitive choice for desalination among various alternative energy sources

Economic evaluation of the integrated SMART desalination plant

Energy Technology Data Exchange (ETDEWEB)

Hwang, Young Dong; Lee, Man Kye; Yeo, Ji Won; Kim, Hee Chul; Chang, Moon Hee

2001-04-01

In this study, an economic evaluation methodology of the integrated SMART desalination plant was established and the economic evaluation of SMART was performed. The plant economics was evaluated with electricity generation costs calculated using approximate estimates of SMART cost data and the result was compared with the result calculated using the SMART design data and estimated bulk materials. In addition, a series of sensitivity studies on the power generation cost was performed for the main economic parameters of SMART Power credit method was used for the economic analysis of the integrated SMART desalination plant. Power credit method is a widely used economic analysis method for the cogeneration plant when the major portion of the energy is used for the electricity generation. In the case of using SMART fot power generation only, the result shows that the electricity generation cost of SMART is higher than that of the alternative power options. However, it can be competitive with the other power options in the limited cases, especially with the gas fired combined plant. In addition, an economic analysis of the integrated SMART desalination plant coupled with MED was performed. The calculated water production cost is in the range of 0.56 approx. 0.88($/m{sup 3}) for the plant availability of 80% or higher, which is close to the study results presented by the various other countries. This indicates that SMART can be considered as a competitive choice for desalination among various alternative energy sources.

Utility-sized Madaras wind plants

Science.gov (United States)

Whitford, D. H.; Minardi, J. E.

1981-01-01

An analysis and technological updating were conducted for the Madaras Rotor Power Plant concept, to determine its ability to compete both technically and economically with horizontal axis wind turbine generators currently under development. The Madaras system uses large cylinders rotating vertically atop each regularly spaced flatcar of a train to propel them, by means of Magnus-effect interaction with the wind, along a circular or oval track. Alternators geared to the wheels of each car generate electrical power, which is transmitted to a power station by a trolley system. The study, consisting of electromechanical design, wind tunnel testing, and performance and cost analyses, shows that utility-sized plants greater than 228 MW in capacity and producing 975,000 kWh/year are feasible. Energy costs for such plants are projected to be between 22% lower and 12% higher than horizontal axis turbine plants of comparable output.

Regulation of abiotic and biotic stress responses by plant hormones

DEFF Research Database (Denmark)

Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

2016-01-01

Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

Comparison of inhalation risks : oil- versus gas-fired urban power plants

International Nuclear Information System (INIS)

Levin, L.

2000-01-01

The risks due to inhalation of emitted trace substances from natural gas-fired power plants tend to be significantly lower than those from oil- or coal-fired plants. A 1994 study suggested that the median inhalation life-time cancer risk from gas-fired plants was about 4 in one billion. This is an acceptable risk range according to the United States Environmental Protection Agency (US EPA) classification of risks. In the same study, median oil plant risks were 8 in one billion. coal plant median risks ranged from 2 to 3 in one billion depending on the grade of coal being burned. The US EPA classifies risks from 1 to one million to one to 10,000 as being in an acceptable risk range. In some cases, gas plants were shown to exhibit higher inhalation risks than oil plants due to terrain, air circulation patterns, enhanced stack or building downwash or mechanical turbulence. Higher concentrations of very potent trace substances could also result in high inhalation risks. An examination of several power plants in an urban area showed that initial judgements about risk can often be incorrect

Responses of Two Invasive Plants Under Various Microclimate Conditions in the Seoul Metropolitan Region

Science.gov (United States)

Song, Uhram; Mun, Saeromi; Ho, Chang-Hoi; Lee, Eun Ju

2012-06-01

The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO2 concentrations differed significantly between the urban (14.8 °C and 439 ppm CO2) and suburban (13.0 °C and 427 ppm CO2) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.

Correlation between heavy metal contents and antioxidants in medicinal plants grown in mining areas

International Nuclear Information System (INIS)

Maharia, R.; Dutta, R.K.; Acharya, R.; Reddy, A.V.R.

2010-01-01

Full texts: Medicinal plants are widely used as alternate therapeutic agents for various diseases. Three medicinal plants grown in copper mining regions of Khetri in Rajasthan was analyzed for heavy metal contents by instrumental neutron activation analysis. The copper levels were found to be two to three folds higher in these plant leaves as compared to the reported copper levels in the medicinal plants grown in environmentally friendly regions. In our previous study on heavy metals in soil and medicinal plant of Khetri region we have shown bioaccumulation of Cu in the medicinal plants. In addition, the levels of Cr, Fe and Zn were also higher. Antioxidant properties of medicinal plants are one of their major therapeutic functionalities. The role of elevated levels of heavy metals in the medicinal plants was studied with respect to their antioxidant properties. Standard procedures were used for measuring total phenols, flavanoids and DPPH assay of these medicinal plants which were correlated with the heavy metals contents of these plants

Examining Dehydration and Hypoxic Stress in Wheat Plants Using a Porous Tube Plant Nutrient Delivery System Developed for Microgravity

Science.gov (United States)

Dreschel, T. W.; Hall, C. R.; Foster, T. E.; Salganic, M.; Warren, L.; Corbett, M.

2005-01-01

The Porous Tube Plant Nutrient Delivery System (PTPNDS) was designed for NASA to grow plants in microgravity of space. The system utilizes a controlled fluid loop to supply nutrients and water to plant roots growing on a ceramic surface moistened by capiflary action. A PTPNDS test bed was developed and utilizing remote sensing systems, spectral analyses procedures, gas-exchange, and fluorescence measurements, we examined differences in plant water status for wheat plants (Triticum aestivum, cv. Perigee) grown in a modified growth chamber during the summers of 2003 and 2004. Some differences in plant performance were detectable in the gas-exchange and fluorescence measurements. For instance, in both years the plants grown with the most available water had the lowest rates of photosynthesis and exhibited higher proportions of non-photochemical quenching particularly under low light levels. In addition, small differences in mean leaf water content between treatments were detected using spectral reflectance analyses.

Fine-grained recognition of plants from images.

Science.gov (United States)

Šulc, Milan; Matas, Jiří

2017-01-01

Fine-grained recognition of plants from images is a challenging computer vision task, due to the diverse appearance and complex structure of plants, high intra-class variability and small inter-class differences. We review the state-of-the-art and discuss plant recognition tasks, from identification of plants from specific plant organs to general plant recognition "in the wild". We propose texture analysis and deep learning methods for different plant recognition tasks. The methods are evaluated and compared them to the state-of-the-art. Texture analysis is only applied to images with unambiguous segmentation (bark and leaf recognition), whereas CNNs are only applied when sufficiently large datasets are available. The results provide an insight in the complexity of different plant recognition tasks. The proposed methods outperform the state-of-the-art in leaf and bark classification and achieve very competitive results in plant recognition "in the wild". The results suggest that recognition of segmented leaves is practically a solved problem, when high volumes of training data are available. The generality and higher capacity of state-of-the-art CNNs makes them suitable for plant recognition "in the wild" where the views on plant organs or plants vary significantly and the difficulty is increased by occlusions and background clutter.

Metal Contamination In Plants Due To Tannery Effluent

Directory of Open Access Journals (Sweden)

Md. Farhad Ali

2015-08-01

Full Text Available Abstract This paper analyzes the determination of heavy metals named Chromium Lead and Cadmium deposited in soil as well as in the plants and vegetables due to the tanning industries of the area of Hazaribagh Dhaka. The tanneries discharge untreated tannery effluents which get mixed with the soil water of rivers and canals in this area. The determination of metals was performed for the soil that was collected from the land adjacent to the canals which bear untreated tannery effluents. The soil is affected with the untreated effluents through the deposition of heavy metals. The metals were furthers deposited into the plants and vegetables grown on that soil. The roots stems and leaves of the plants of Jute Corchorus capsularis and Spinach Basella alba grown on that soil were analyzed for determining these metals. Extreme amount of chromium was found for plants and again Lead Cadmium were found in higher amount in these parts of the two plants. These two plants are taken as a popular vegetables extensively. In case of soil the amount of Chromium Lead and Cadmium were analyzed as 87 mgL 0.131 mgL and 0.190 mgL respectively. For the roots stems and leaves of Jute Corchorus capsularis the average values are 115.62 mgL for Chromium 11.25 mgL for Lead and 2.27 mgL for Cadmium respectively. Again in case of Spinach Basella alba 124.42 mgL was found for Chromium 7.38 mgL for lead and 2.97 mgL for Cadmium as average values for these parts of the two trees. All the observed values of metals of Chromium Lead and Cadmium are higher than the permissible and specially for Chromium the amount is extremely higher.

Plant regeneration protocol of Andrographis paniculata (Burm. f ...

African Journals Online (AJOL)

Plant regeneration protocol of Andrographis paniculata (Burm. f.) - an important medicinal plant. ... Inclusion of 1.0 mg/l 1-naphthalene acetic acid (NAA) in the culture medium along with BA + Ads promoted a higher rate of shoot bud regeneration. Maximum mean number of shoot bud per explant (28.6) was achieved on the ...

[Content and distribution of active components in cultivated and wild Taxus chinensis var. mairei plants].

Science.gov (United States)

Yu, Shao-Shuai; Sun, Qi-Wu; Zhang, Xiao-Ping; Tian, Sheng-Ni; Bo, Pei-Lei

2012-10-01

Taxus chinensis var. mairei is an endemic and endangered plant species in China. The resources of T. chinensis var. mairei have been excessively exploited due to its anti-cancer potential, accordingly, the extant T. chinensis var. mairei population is decreasing. In this paper, ultrasonic extraction and HPLC were adopted to determine the contents of active components paclitaxel, 7-xylosyltaxol and cephalomannine in cultivated and wild T. chinensis var. mairei plants, with the content distribution of these components in different parts of the plants having grown for different years and at different slope aspects investigated. There existed obvious differences in the contents of these active components between cultivated and wild T. chinensis var. mairei plants. The paclitaxel content in the wild plants was about 0.78 times more than that in the cultivated plants, whereas the 7-xylosyltaxol and cephalomannine contents were slishtly higher in the cultivated plants. The differences in the three active components contents between different parts and tree canopies of the plants were notable, being higher in barks and upper tree canopies. Four-year old plants had comparatively higher contents of paclitaxel, 7-xylosyltaxol and cephalomannine (0.08, 0.91 and 0.32 mg x g(-1), respectively), and the plants growing at sunny slope had higher contents of the three active components, with significant differences in the paclitaxel and 7-xylosyltaxol contents and unapparent difference in the cephalomannine content of the plants at shady slope. It was suggested that the accumulation of the three active components in T. chinensis var. mairei plants were closely related to the sunshine conditions. To appropriately increase the sunshine during the artificial cultivation of T. chinensis var. mairei would be beneficial to the accumulation of the three active components in T. chinensis var. mairei plants.

Industrial power plants. Modernisation or replacement plant engineering. Framework conditions and future development; Industriekraftwerke. Modernisierung oder Ersatzanlagenbau. Rahmenbedingungen und zukuenftige Entwicklungen

Energy Technology Data Exchange (ETDEWEB)

Briese, Dirk; Gatena, Jens [trend:research GmbH, Bremen (Germany)

2014-08-01

For a number of years, a trend towards decentralised power supply, partly due to the 'Energiewende' and other reasons, could be observed. In Germany currently around 200 industrial power plants with a respective installed capacity of over 10 MW{sub el} exist. About one third of these plants were built between 1990 and 2010. Plant operators therefore face the question, if they should modernise the old assets or build new installations in the coming years. Whereas a modernisation bears cost and time advantages, amongst other things, higher efficiency and improved flexibility can be achieved with new plants. (orig.)

Plant feeding promotes diversification in the Crustacea.

Science.gov (United States)

Poore, Alistair G B; Ahyong, Shane T; Lowry, James K; Sotka, Erik E

2017-08-15

About half of the world's animal species are arthropods associated with plants, and the ability to consume plant material has been proposed to be an important trait associated with the spectacular diversification of terrestrial insects. We review the phylogenetic distribution of plant feeding in the Crustacea, the other major group of arthropods that commonly consume plants, to estimate how often plant feeding has arisen and to test whether this dietary transition is associated with higher species numbers in extant clades. We present evidence that at least 31 lineages of marine, freshwater, and terrestrial crustaceans (including 64 families and 185 genera) have independently overcome the challenges of consuming plant material. These plant-feeding clades are, on average, 21-fold more speciose than their sister taxa, indicating that a shift in diet is associated with increased net rates of diversification. In contrast to herbivorous insects, most crustaceans have very broad diets, and the increased richness of taxa that include plants in their diet likely results from access to a novel resource base rather than host-associated divergence.

Physiological characteristics of high yield under cluster planting: photosynthesis and canopy microclimate of cotton

Directory of Open Access Journals (Sweden)

Ting-ting Xie

2016-01-01

Full Text Available Cotton produces more biomass and economic yield when cluster planting pattern (three plants per hole than in a traditional planting pattern (one plant per hole, even at similar plant densities, indicating that individual plant growth is promoted by cluster planting. The causal factors for this improved growth induced by cluster planting pattern, the light interception, canopy microclimate and photosynthetic rate of cotton were investigated in an arid region of China. The results indicated that the leaf area index and light interception were higher in cluster planting, and significantly different from those in traditional planting during the middle and late growth stages. Cotton canopy humidity at different growth stages was increased but canopy temperatures were reduced by cluster planting. In the later growth stage of cluster planting, the leaf chlorophyll content was higher and the leaf net photosynthetic rate and canopy photosynthetic rate were significantly increased in comparing with traditional planting pattern. We concluded that differences in canopy light interception and photosynthetic rate were the primary factors responsible for increased biomass production and economic yield in cluster planting compared with the traditional planting of cotton.

Subcellular site and nature of intracellular cadmium in plants

International Nuclear Information System (INIS)

Wagner, G.J.

1979-01-01

The mechanisms underlying heavy metal accumulation, toxicity and tolerance in higher plants are poorly understood. Since subcellular processes are undoubtedly involved in all these phenomena, it is of interest to study the extent of, subcellular site of and nature of intracellularly accumulated cadmium in higher plants. Whole plants supplied 109 CdCl 2 or 112 CdSO 4 accumulated Cd into roots and aerial tissues. Preparation of protoplasts from aerial tissue followed by subcellular fractionation of the protoplasts to obtain intact vacuoles, chloroplasts and cytosol revealed the presence of Cd in the cytosol but not in vacuoles or chloroplasts. Particulate materials containing other cell components were also labeled. Of the 109 Cd supplied to plants, 2 to 10% was recovered in both cytosol preparations and in particulate materials. Cytosol contained proteinaceous--Cd complexes, free metal and low molecular weight Cd complexes. Labeling of protoplasts gave similar results. No evidence was obtained for the production of volatile Cd complexes in tobacco

The shift from plant-plant facilitation to competition under severe water deficit is spatially explicit.

Science.gov (United States)

O'Brien, Michael J; Pugnaire, Francisco I; Armas, Cristina; Rodríguez-Echeverría, Susana; Schöb, Christian

2017-04-01

The stress-gradient hypothesis predicts a higher frequency of facilitative interactions as resource limitation increases. Under severe resource limitation, it has been suggested that facilitation may revert to competition, and identifying the presence as well as determining the magnitude of this shift is important for predicting the effect of climate change on biodiversity and plant community dynamics. In this study, we perform a meta-analysis to compare temporal differences of species diversity and productivity under a nurse plant ( Retama sphaerocarpa ) with varying annual rainfall quantity to test the effect of water limitation on facilitation. Furthermore, we assess spatial differences in the herbaceous community under nurse plants in situ during a year with below-average rainfall. We found evidence that severe rainfall deficit reduced species diversity and plant productivity under nurse plants relative to open areas. Our results indicate that the switch from facilitation to competition in response to rainfall quantity is nonlinear. The magnitude of this switch depended on the aspect around the nurse plant. Hotter south aspects under nurse plants resulted in negative effects on beneficiary species, while the north aspect still showed facilitation. Combined, these results emphasize the importance of spatial heterogeneity under nurse plants for mediating species loss under reduced precipitation, as predicted by future climate change scenarios. However, the decreased water availability expected under climate change will likely reduce overall facilitation and limit the role of nurse plants as refugia, amplifying biodiversity loss.

Uptake and translocation of 109Cd and stable Cd within tobacco plants (Nicotiana sylvestris)

International Nuclear Information System (INIS)

Rosén, K.; Eriksson, J.; Vinichuk, M.

2012-01-01

The availability, uptake, and translocation of recently added ( 109 Cd) and naturally occurring (stable) soil Cd within tobacco plants were compared. 109 Cd was added to soil in two treatments, A (0.25 MBq kg soil −1 DW) and B (eight-fold dose): stable Cd was measured in both treatments. Both the added and the stable Cd were higher in leaves and reproductive structures of the plant than in stalks and roots. The uptake of 109 Cd was 5.3 kBq plant −1 for treatment A and 36.7 kBq plant −1 for treatment B, and about 26 μg plant −1 for stable Cd. Leaves of the tobacco plants accumulated 40–45% of the total 109 Cd and about 50% of total stable Cd taken up by the plant. Cadmium concentration in the plant was three times higher than in roots and two times higher than the concentration in soil: the concentration in roots was lower than in the soil. - Capsule: The availability, uptake, and translocation of recently added ( 109 Cd) and naturally occurring (stable) soil Cd within tobacco plants (Nicotiana sylvestris) were investigated. - Highlights: ► We compared uptake recently added and naturally occurring soil Cd by tobacco plant. ► Both added and stable Cd display similar uptake and translocation within the plant. ► Leaves of tobacco plants accumulate half of the total Cd taken up by the plant. ► Recently added 109 Cd to soil is more available than naturally occurring cadmium.

Assessment of bioaccumulation of REEs by plant species in a mining area by INAA

International Nuclear Information System (INIS)

Hossain Md Anawar; Maria do Carmo Freitas; Nuno Canha; Isabel Dionisio; Ho Manh Dung; Catarina Galinha; Pacheco, A.M.G.

2012-01-01

Native plant species, lichens and tailings, sampled from a copper-sulphide mining area located in southern-eastern Portugal, were analysed by neutron activation analysis (INAA) for determination of rare earth elements (REEs). Values of ΣREEs and individual REEs concentration of tailing samples are higher than those of natural background concentrations. The higher values of REEs are found in modern slags and the mixture of oxidized gossan and sulphide disseminated country rocks when compared with the alluvial sediments contaminated by mine tailings. The total concentrations of light REEs are higher than those of heavy REEs in all tailing samples. Distribution patterns of PAAS-normalized REEs in mine tailings show slightly LREE enriched and flat HREE pattern with negative Eu anomaly. Lichens accumulated higher concentration of lanthanides than vascular plants. The elevated levels of REEs in lichen, native plant species and tailing samples reflect the contamination of REEs in Sao Domingos mining area. The Carlina corymbosa, Erica australis and Lavandula luisierra accumulated the higher amounts of La, Ce and other REEs than the other plant species grown in this mining area. (author)

Preparation and practice for nuclear power plant operation

International Nuclear Information System (INIS)

Wu Xuesong; Lu Tiezhong

2015-01-01

The operational preparation of the nuclear power plant is an important work in nuclear power plant production preparation. Due to the construction period of nuclear power plant from starting construction to production is as long as five years, the professional requirements of nuclear power operation are very strict, and the requirements for nuclear safety are also extremely high. Especially after the Fukushima accident, higher requirements for the safe operation of nuclear power plant are posed by competent authorities of the national level, regulatory authorities and each nuclear power groups. Based on the characteristics of the construction phase of nuclear power plant and in combination with engineering practice, this paper expounds the system established in the field of nuclear power plant operation and generally analyses the related management innovation. (authors)

Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

Energy Technology Data Exchange (ETDEWEB)

Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

1999-10-01

Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

Effects of various planting ratios on the performance of maize and ...

African Journals Online (AJOL)

The experiment was conducted at the Teaching and Research Farm of Ambrose Alli University, Ekpoma to evaluate the performance of maize and cowpea planted at various replacement ratios. Weight of grains per plant and grain yield were higher in cowpea in maize-cowpea intercrop planted in ratio 2:1. Based on the ...

Overexpression of monoubiquitin improves photosynthesis in transgenic tobacco plants following high temperature stress.

Science.gov (United States)

Tian, Fengxia; Gong, Jiangfeng; Zhang, Jin; Feng, Yanan; Wang, Guokun; Guo, Qifang; Wang, Wei

2014-09-01

The ubiquitin/26S proteasome system (Ub/26S) is implicated in abiotic stress responses in plants. In this paper, transgenic tobacco plants overexpressing Ta-Ub2 from wheat were used to study the functions of Ub in the improvement of photosynthesis under high temperature (45°C) stress. We observed higher levels of Ub conjugates in transgenic plants under high temperature stress conditions compared to wild type (WT) as a result of the constitutive overexpression of Ta-Ub2, suggesting increased protein degradation by the 26S proteasome system under high temperature stress. Overexpressing Ub increased the photosynthetic rate (Pn) of transgenic tobacco plants, consistent with the improved ATPase activity in the thylakoid membrane and enhanced efficiency of PSII photochemistry. The higher D1 protein levels following high temperature stress in transgenic plants than WT were also observed. These findings imply that Ub may be involved in tolerance of photosynthesis to high temperature stress in plants. Compared with WT, the transgenic plants showed lower protein carbonylation and malondialdehyde (MDA) levels, less reactive oxygen species (ROS) accumulation, but higher antioxidant enzyme activity under high temperature stress. These findings suggest that the improved antioxidant capacity of transgenic plants may be one of the most important mechanisms underlying Ub-regulated high temperature tolerance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Within-plant distribution of Aulacorthum solani (Hemiptera: Aphididae), on various greenhouse plants with implications for control.

Science.gov (United States)

Jandricic, S E; Mattson, N S; Wraight, S P; Sanderson, J P

2014-04-01

Foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), has recently undergone a status change from an occasional pest to a serious pest in greenhouses of North America and the United Kingdom. Little nonanecdotal information exists on the ecology of this insect in greenhouse crops. To help improve integrated pest management decisions for A. solani, the within-plant distribution of this pest was explored on a variety of common greenhouse plants in both the vegetative and flowering stage. This aphid generally was found on lower leaves of vegetative plants, but was found higher in the canopy on reproductive plants (on flowers, flower buds, or upper leaves). Aphid numbers were not consistently positively correlated with total leaf surface areas within plant strata across plant species. Thus, the observed differences in preferred feeding sites on vegetative versus flowering plants are possibly a response to differences in nutritional quality of the various host-plant tissues. Despite being anecdotally described as a "stem-feeding aphid," A. solani was rarely found feeding on stems at the population densities established in our tests, with the exception of racemes of scarlet sage (Salvia splendans). Although some previous reports suggested that A. solani prefers to feed on new growth of plants, our results indicate that mature leaves are preferred over growing tips and young leaves. The implications of the within-plant feeding preferences of A. solani populations with respect to both biological and chemical control are discussed.

Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors

International Nuclear Information System (INIS)

Mortassim, A.; Misdaq, M.A.; Naaman, A

2009-01-01

The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in f ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [fr

Dimorphic cypsela germination and plant growth in Synedrella nodiflora (L. Gaertn. (Asteraceae

Directory of Open Access Journals (Sweden)

PRM Souza Filho

Full Text Available Synedrella nodiflora is a weed species that has dimorphic cypselas: winged peripheral and lanceolate shaped central. The aim of this work is to describe the reproductive capability by measuring dimorphic cypselas morphology, imbibition rates and germinative patterns under temperature, light quality and water availability gradients, and compare the plant growth between two light treatments. The central cypselas were lighter, longer and its pappi were more elongated than the peripheral ones, favoring its dispersion. Neither type had deep dormancy and both of them germinated with the same pattern under the optimum conditions. Both cypselas showed higher germinability in temperatures between 25 and 30 °C, under white light and high water availability, although there are some differences between the types, mainly at dark treatments. Plants grown in direct sunlight accumulated more biomass, allowing for higher plant development and inflorescence production, although shaded light plants capitulum had a higher central: peripheral ratio than the direct sunlight treatment. S. nodiflora cypselas germinate better in unfiltered light places, although the plants are adapted to shady conditions. The species showed high germination potential over a wide range of environmental conditions, as well as fast plant development. All of these features favor distribution in environmental sites.

Cadmium accumulation in sunflower plants influenced by arbuscular mycorrhiza.

Science.gov (United States)

de Andrade, Sara Adrián López; da Silveira, Adriana Parada Dias; Jorge, Renato Atílio; de Abreu, Mônica Ferreira

2008-01-01

In order to investigate the cadmium (Cd) accumulation patterns and possible alleviation of Cd stress by mycorrhization, sunflower plants (Helianthus annuus L.) were grown in the presence or absence of Cd (20 micromol L(-1)) and inoculated or not inoculated with the arbuscular mycorrhizal fungus (AMF) Glomus intraradices. No visual symptoms of Cd phytotoxicity were observed; nevertheless, in non-mycorrhizal plants the presence of Cd decreased plant growth. The addition of Cd had no significant effect on either mycorrhizal colonization or the amount of extra-radical mycelia that was produced by the AMF. Cd accumulated mainly in roots; only 22% of the total Cd absorbed was translocated to the shoots, where it accumulated to an average of 228 mg Cd kg(-1). Although the shoot-to-root ratio of Cd was similar in both the AMF inoculated and non-inoculated plants, the total absorbed Cd was 23% higher in mycorrhizal plants. Cd concentration in AMF extra-radical mycelium was 728 microg g(-1) dry weight. Despite the greater absorption of Cd, mycorrhizal plants showed higher photosynthetic pigment concentrations and shoot P contents. Cd also influenced mineral nutrition, leading to decreased Ca and Cu shoot concentrations; N, Fe and Cu shoot contents; and increased S and K shoot concentrations. Cd induced guaiacol peroxidase activity in roots in both mycorrhizal and non-mycorrhizal plants, but this increase was much more accentuated in non-mycorrhizal roots. In conclusion, sunflower plants associated with G. intraradices were less sensitive to Cd stress than non-mycorrhizal plants. Mycorrhizal sunflowers showed enhanced Cd accumulation and some tolerance to excessive Cd concentrations in plant tissues.

Bioelectric potentials in the soil-plant system

Science.gov (United States)

Pozdnyakov, A. I.

2013-07-01

A detailed study of the electric potentials in the soil-plant system was performed. It was found that the electric potential depends on the plant species and the soil properties. A theoretical interpretation of the obtained data was given. All the plants, independently from their species and their state, always had a negative electric potential relative to the soil. The electric potential of the herbaceous plants largely depended on the leaf area. In some plants, such as burdock ( Arctium lappa) and hogweed ( Heracleum sosnowskyi), the absolute values of the negative electric potential exceeded 100 mV. The electric potential was clearly differentiated by the plant organs: in the flowers, it was lower than in the leaves; in the leaves, it was usually lower than in the leaf rosettes and stems. The electric potentials displayed seasonal dynamics. As a rule, the higher the soil water content, the lower the electric potential of the plants. However, an inverse relationship was observed for dandelions ( Taraxacum officinale). It can be supposed that the electric potential between the soil and the plant characterizes the vital energy of the plant.

Key regulatory challenges for future nuclear power plants

International Nuclear Information System (INIS)

Todreas, Neil E.

2001-01-01

Key regulatory challenges for future nuclear power plants are concerned with fuel and cladding materials taken to higher burnup and operated at higher temperatures. Particular challenges are related to reduction in waste toxicity, understanding and control of coolant corrosion, qualification of fuel particles, new maintenance practices

Plant protein and secondary metabolites influence diet selection in a mammalian specialist herbivore

Science.gov (United States)

Amy C. Ulappa; Rick G. Kelsey; Graham G. Frye; Janet L. Rachlow; LIsa A. Shipley; Laura Bond; Xinzhu Pu; Jennifer Sorensen. Forbey

2014-01-01

For herbivores, nutrient intake is limited by the relatively low nutritional quality of plants and high concentrations of potentially toxic defensive compounds (plant secondary metabolites [PSMs]) produced by many plants. In response to phytochemical challenges, some herbivores selectively forage on plants with higher nutrient and lower PSM concentrations relative to...

Radionuclide transfer to meadow plants

International Nuclear Information System (INIS)

Sanzharova, N.; Fesenko, S.; Belli, M.; Arkhipov, A.; Ivanova, T.; Perepelyatnikov, G.; Tsvetnova, O.

1996-01-01

Experimental data on 90 Sr and 137 Cs transfer to plants of natural and semi-natural meadows selected in the main CIS region contaminated due to the ChNPP accident are discussed. The highest TF's in grass stand are obtained for peatlands, and minimal ones - for dry meadows. 137 Cs content in plants decreased after the accident, on average, by a factor of 2-4. The dynamics of 137 Cs uptake by plants depends on meadow and soil properties. The first half life of 137 Cs transfer to plants change from 2,0 to 2,2 years and the second (slower) period half life change from 4,0 to 12 years for different meadow types. 90 Sr TF's are higher than those obtained for 137 Cs. The correlation between soil parameters and TP's are shown. 137 Cs TF's in grass stand depend on meadow type and decrease in the following order: peatlands> flood plain and wet (lowland) meadows> dry meadows

Model-based plant-wide optimization of large-scale lignocellulosic bioethanol plants

DEFF Research Database (Denmark)

Prunescu, Remus Mihail; Blanke, Mogens; Jakobsen, Jon Geest

2017-01-01

Second generation biorefineries transform lignocellulosic biomass into chemicals with higher added value following a conversion mechanism that consists of: pretreatment, enzymatic hydrolysis, fermentation and purification. The objective of this study is to identify the optimal operational point...... with respect to maximum economic profit of a large scale biorefinery plant using a systematic model-based plantwide optimization methodology. The following key process parameters are identified as decision variables: pretreatment temperature, enzyme dosage in enzymatic hydrolysis, and yeast loading per batch...... in fermentation. The plant is treated in an integrated manner taking into account the interactions and trade-offs between the conversion steps. A sensitivity and uncertainty analysis follows at the optimal solution considering both model and feed parameters. It is found that the optimal point is more sensitive...

Performance Comparison on Repowering of a Steam Power Plant with Gas Turbines and Solid Oxide Fuel Cells

DEFF Research Database (Denmark)

Rokni, Masoud

2016-01-01

Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines into an exi......Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines...... into an existing steam cycle which was built decades ago. Thus, traditional repowering results in combined cycles (CC). High temperature fuel cells (such as solid oxide fuel cell (SOFC)) could also be used as a topping cycle, achieving even higher global plant efficiency and even lower specific CO2 emissions....... Decreasing the operating temperature in a SOFC allows the use of less complex materials and construction methods, consequently reducing plant and the electricity costs. A lower working temperature makes it also suitable for topping an existing steam cycle, instead of gas turbines. This is also the target...

Response of sunflower to different planting dates in cotton based cropping system

International Nuclear Information System (INIS)

Yousaf, M.; Shakoor, A.; Rana, M.A.

2007-01-01

A field study on sunflower (Helianthus annuus L) was conducted for three. years (1991-1993) on different planting dates. Two hybrids (Hysun-33 and PI-6480) were sown on five different dates with 15 days interval from January 15 to March 15 at Cotton Research Station, Multan. Significant higher seed yield of 1880 and 2097 kg ha-1 was obtained when the crop was planted on February 1 and 15 than other treatments. The yield significantly decreased when sunflower was planted on January 15 (1264 kg ha-l), March 1 (1382 kg ha-l) and March 15 (927 kg hall. Maturity period was longest (128 days) of early sown (January 15) and shortest of late sown (March 15) sunflower hybrids. Therefore, it can be concluded that sunflower planted on February 1 to 15 gave higher seed yield as well as allowed enough time for land preparation and thereby, planting of cotton crop in the same field during its regular planting time. (author)

Response of plants to high concentrations of uranium stress and the screening of remediation plants

International Nuclear Information System (INIS)

Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

2013-01-01

Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

IRON REDUCTASE SYSTEMS ON THE PLANT PLASMA-MEMBRANE - A REVIEW

NARCIS (Netherlands)

MOOG, PR; BRUGGEMANN, W

1994-01-01

Higher plant roots, leaf mesophyll tissue, protoplasts as well as green algae are able to reduce extra-cellular ferricyanide and ferric chelates. In roots of dicotyledonous and nongraminaceous, monocotyledonous plants, the rate of ferric reduction is increased by iron deficiency. This reduction is

[Research on source profile of aerosol organic compounds in leather plant].

Science.gov (United States)

Wang, Bo-Guang; Zhou, Yan; Feng, Zhi-Cheng; Liu, Hui-Xuan

2009-04-15

Through investigating current air pollution condition for PM10 in every factories of different style leather plants in Pearl River Delta, characteristic profile of semi-volatile organic compounds in PM10 emitted from leather factories and their contents were researched by using ultrasonic and gas chromatography and mass spectrum technology. The 6 types of organic compounds containing 46 species in total were found in the collected samples, including phenyl compounds, alcohols, PAHs, acids, esters and amides. The concentrations of PM10 in leather tanning plant, leather dying plant and man-made leather plant were 678.5, 454.5, 498.6 microgm x m(-3) respectively, and concentration of organic compounds in PM10 were 10.04, 6.89, 14.21 microg x m(-3) in sequence. The more important type of pollutants in each leather plants had higher contribution to total organic mass as follows, esters and amides in tanning plants profile account for 43.47% and 36.51% respectively; esters and alcohols in dying plants profiles account for 52.52% and 16.16% respectively; esters and amide in man-made leather plant have the highest content and account for 57.07% and 24.17% respectively. In the aerosol organic source profiles of tested leather plants, 9-octadecenamide was the abundant important species with the weight of 26.15% in tanning plant, and Bis(2-ethylhexyl) phthalate was up to 44.19% in the dying plant, and Bis(2-ethylhexyl) maleate and 1-hydroxy-piperidine had obviously higher weight in man-made plant than the other two plants.

RAM investigation of coal-fired thermal power plants: A case study

Directory of Open Access Journals (Sweden)

D. Bose

2012-04-01

Full Text Available Continuous generation of electricity of a power plant depends on the higher availability of its components/equipments. Higher availability of the components/equipments is inherently associated with their higher reliability and maintainability. This paper investigates the reliability, availability and maintainability (RAM characteristics of a 210 MW coal-fired thermal power plant (Unit-2 from a thermal power station in eastern region of India. Critical mechanical subsystems with respect to failure frequency, reliability and maintainability are identified for taking necessary measures for enhancing availability of the power plant and the results are compared with Unit-1 of the same Power Station. Reliability-based preventive maintenance intervals (PMIs at various reliability levels of the subsystems are estimated also for performing their preventive maintenance (PM. The present paper highlights that in the Unit-2, Economizer (ECO & Furnace Wall Tube (FWT exhibits lower reliability as compared to the other subsystems and Economizer (ECO & Baffle Wall Tube (BWT demands more improvement in maintainability. Further, it has been observed that FSH followed Decreasing Failure Rate (DFR and Economizer (ECO is the most critical subsystem for both the plants. RAM analysis is very much effective in finding critical subsystems and deciding their preventive maintenance program for improving availability of the power plant as well as the power supply.

High plant species diversity indirectly mitigates CO 2- and N-induced effects on grasshopper growth

Science.gov (United States)

Strengbom, Joachim; Reich, Peter B.; Ritchie, Mark E.

2008-09-01

We examined how elevated atmospheric [CO 2] and higher rate of nitrogen (N) input may influence grasshopper growth by changing food plant quality and how such effects may be modified by species diversity of the plant community. We reared grasshopper nymphs ( Melanoplus femurrubrum) on Poa pratensis from field-grown monocultures or polycultures (16 species) that were subjected to either ambient or elevated levels of CO 2 and N. Grasshopper growth rate was higher on P. pratensis leaves grown in monocultures than in polycultures, higher on P. pratensis grown under elevated than under ambient [CO 2], and higher on P. pratensis grown under elevated than under ambient [N]. The higher growth rate observed on P. pratensis exposed to elevated [CO 2] was, however, less pronounced for polyculture- than monoculture-grown P. pratensis. Growth rate of the grasshoppers was positively correlated with leaf [N], [C], and concentration of soluble carbohydrates + lipids. Concentration of non-structural carbohydrates + lipids was higher in leaves grown under elevated than under ambient [CO 2], and the difference between P. pratensis grown under ambient and elevated [CO 2] was greater for monoculture- than polyculture-grown P. pratensis. In addition, leaf N concentration was higher in P. pratensis grown in monocultures than in polycultures, suggesting that plant species richness, indirectly, may influence insect performance by changed nutritional value of the plants. Because we found interactive effects between all factors included ([CO 2], [N], and plant species diversity), our results suggest that these parameters may influence plant-insect interactions in a complex way that is not predictable from the sum of single factor manipulations.

Climate interacts with soil to produce beta diversity in Californian plant communities.

Science.gov (United States)

Fernandez-Going, B M; Harrison, S P; Anacker, B L; Safford, H D

2013-09-01

Spatially distinct communities can arise through interactions and feedbacks between abiotic and biotic factors. We suggest that, for plants, patches of infertile soils such as serpentine may support more distinct communities from those in the surrounding non-serpentine matrix in regions where the climate is more productive (i.e., warmer and/or wetter). Where both soil fertility and climatic productivity are high, communities may be dominated by plants with fast-growing functional traits, whereas where either soils or climate impose low productivity, species with stress-tolerant functional traits may predominate. As a result, both species and functional composition may show higher dissimilarity between patch and matrix in productive climates. This pattern may be reinforced by positive feedbacks, in which higher plant growth under favorable climate and soil conditions leads to higher soil fertility, further enhancing plant growth. For 96 pairs of sites across a 200-km latitudinal gradient in California, we found that the species and functional dissimilarities between communities on infertile serpentine and fertile non-serpentine soils were higher in more productive (wetter) regions. Woody species had more stress-tolerant functional traits on serpentine than non-serpentine soil, and as rainfall increased, woody species functional composition changed toward fast-growing traits on non-serpentine, but not on serpentine soils. Soil organic matter increased with rainfall, but only on non-serpentine soils, and the difference in organic matter between soils was positively correlated with plant community dissimilarity. These results illustrate a novel mechanism wherein climatic productivity is associated with higher species, functional, and landscape-level dissimilarity (beta diversity).

Disposable Bioreactors for Plant Micropropagation and Mass Plant Cell Culture

Science.gov (United States)

Ducos, Jean-Paul; Terrier, Bénédicte; Courtois, Didier

Different types of bioreactors are used at Nestlé R&D Centre - Tours for mass propagation of selected plant varieties by somatic embryogenesis and for large scale culture of plants cells to produce metabolites or recombinant proteins. Recent studies have been directed to cut down the production costs of these two processes by developing disposable cell culture systems. Vegetative propagation of elite plant varieties is achieved through somatic embryogenesis in liquid medium. A pilot scale process has recently been set up for the industrial propagation of Coffea canephora (Robusta coffee). The current production capacity is 3.0 million embryos per year. The pre-germination of the embryos was previously conducted by temporary immersion in liquid medium in 10-L glass bioreactors. An improved process has been developed using a 10-L disposable bioreactor consisting of a bag containing a rigid plastic box ('Box-in-Bag' bioreactor), insuring, amongst other advantages, a higher light transmittance to the biomass due to its horizontal design. For large scale cell culture, two novel flexible plastic-based disposable bioreactors have been developed from 10 to 100 L working volumes, validated with several plant species ('Wave and Undertow' and 'Slug Bubble' bioreactors). The advantages and the limits of these new types of bioreactor are discussed, based mainly on our own experience on coffee somatic embryogenesis and mass cell culture of soya and tobacco.

Screening agrochemicals as potential protectants of plants against ozone phytotoxicity.

Science.gov (United States)

Saitanis, Costas J; Lekkas, Dimitrios V; Agathokleous, Evgenios; Flouri, Fotini

2015-02-01

We tested seven contemporary agrochemicals as potential plant protectants against ozone phytotoxicity. In nine experiments, Bel-W3 tobacco plants were experienced weekly exposures to a) 80 nmol mol(-1) of ozone-enriched or ozone-free air in controlled environment chambers, b) an urban air polluted area, and c) an agricultural-remote area. Ozone caused severe leaf injury, reduced chlorophylls' and total carotenoids' content, and negatively affected photosynthesis and stomatal conductance. Penconazole, (35% ± 8) hexaconazole (28% ± 5) and kresoxim-methyl (28% ± 15) showed higher plants' protection (expressed as percentage; mean ± s.e.) against ozone, although the latter exhibited a high variability. Azoxystrobin (21% ± 15) showed lower protection efficacy and Benomyl (15% ± 9) even lower. Trifloxystrobin (7% ± 11) did not protect the plants at all. Acibenzolar-S-methyl + metalaxyl-M (Bion MX) (-6% ± 17) exhibited the higher variability and contrasting results: in some experiments it showed some protection while in others it intensified the ozone injury by causing phytotoxic symptoms on leaves, even in control plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carbon and Nitrogen Isotopic Survey of Northern Peruvian Plants: Baselines for Paleodietary and Paleoecological Studies

Science.gov (United States)

Szpak, Paul; White, Christine D.; Longstaffe, Fred J.; Millaire, Jean-François; Vásquez Sánchez, Víctor F.

2013-01-01

The development of isotopic baselines for comparison with paleodietary data is crucial, but often overlooked. We review the factors affecting the carbon (δ13C) and nitrogen (δ15N) isotopic compositions of plants, with a special focus on the carbon and nitrogen isotopic compositions of twelve different species of cultivated plants (n = 91) and 139 wild plant species collected in northern Peru. The cultivated plants were collected from nineteen local markets. The mean δ13C value for maize (grain) was −11.8±0.4 ‰ (n = 27). Leguminous cultigens (beans, Andean lupin) were characterized by significantly lower δ15N values and significantly higher %N than non-leguminous cultigens. Wild plants from thirteen sites were collected in the Moche River Valley area between sea level and ∼4,000 meters above sea level (masl). These sites were associated with mean annual precipitation ranging from 0 to 710 mm. Plants growing at low altitude sites receiving low amounts of precipitation were characterized by higher δ15N values than plants growing at higher altitudes and receiving higher amounts of precipitation, although this trend dissipated when altitude was >2,000 masl and MAP was >400 mm. For C3 plants, foliar δ13C was positively correlated with altitude and precipitation. This suggests that the influence of altitude may overshadow the influence of water availability on foliar δ13C values at this scale. PMID:23341996

Carbon and nitrogen isotopic survey of northern peruvian plants: baselines for paleodietary and paleoecological studies.

Directory of Open Access Journals (Sweden)

Paul Szpak

Full Text Available The development of isotopic baselines for comparison with paleodietary data is crucial, but often overlooked. We review the factors affecting the carbon (δ(13C and nitrogen (δ(15N isotopic compositions of plants, with a special focus on the carbon and nitrogen isotopic compositions of twelve different species of cultivated plants (n = 91 and 139 wild plant species collected in northern Peru. The cultivated plants were collected from nineteen local markets. The mean δ(13C value for maize (grain was -11.8±0.4 ‰ (n = 27. Leguminous cultigens (beans, Andean lupin were characterized by significantly lower δ(15N values and significantly higher %N than non-leguminous cultigens. Wild plants from thirteen sites were collected in the Moche River Valley area between sea level and ∼4,000 meters above sea level (masl. These sites were associated with mean annual precipitation ranging from 0 to 710 mm. Plants growing at low altitude sites receiving low amounts of precipitation were characterized by higher δ(15N values than plants growing at higher altitudes and receiving higher amounts of precipitation, although this trend dissipated when altitude was >2,000 masl and MAP was >400 mm. For C(3 plants, foliar δ(13C was positively correlated with altitude and precipitation. This suggests that the influence of altitude may overshadow the influence of water availability on foliar δ(13C values at this scale.

Plant host finding by parasitic plants: a new perspective on plant to plant communication.

Science.gov (United States)

Mescher, Mark C; Runyon, Justin B; De Moraes, Consuelo M

2006-11-01

Plants release airborne chemicals that can convey ecologically relevant information to other organisms. These plant volatiles are known to mediate a large array of, often complex, interactions between plants and insects. It has been suggested that plant volatiles may have similar importance in mediating interactions among plant species, but there are few well-documented examples of plant-to-plant communication via volatiles, and the ecological significance of such interactions has been much debated. To date, nearly all studies of volatile-mediated interactions among plant species have focused on the reception of herbivore-induced volatiles by neighboring plants. We recently documented volatile effects in another system, demonstrating that the parasitic plant Cuscuta pentagona uses volatile cues to locate its hosts. This finding may broaden the discussion regarding plant-to-plant communication, and suggests that new classes of volatile-meditated interactions among plant species await discovery.

Plant capacity uprating problems and solutions

International Nuclear Information System (INIS)

Bruster, L.H.; Nicholson, J.M.

1992-01-01

The changing economics associated with electric power generation require producers and suppliers of electrical energy to adopt new strategies for production and pricing. New challenges face utility managers as they attempt to position themselves to be low-cost producers of electricity. Owner/operators of nuclear power plants have many strategies and tactics by which to establish or maintain their competitive positions as electric power producers. One simple approach is to increase plant output without investing significant capital in new facilities. This paper reports that this objective can be accomplished by extending the operation of nuclear plants into their stretch power rating, or to higher core power levels if system/component margins permit

Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

International Nuclear Information System (INIS)

Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

1993-01-01

The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activate the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid (half-lives in hours), and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated

Environmental study of the Wairakei Power Plant. [Effects of hydroelectric power plant on ecology of Waikato River Basin, New Zealand

Energy Technology Data Exchange (ETDEWEB)

Axtmann, R C

1974-12-01

Physical, chemical, biological, ecological, and aesthetic aspects of the Wairakei Power Plant are examined, in varying detail, but with primary emphasis on the chemical and thermal effluents. When flows are average or higher in the Waikato River, the Plant's environmental effects are not overly severe. However, operating requirements for the Waikato Hydro-electric System are such that the Plant sporadically produces wastes that may affect the human and natural environment adversely. These adverse effects are not presently too serious, but suggestions are made for improving the Plant's overall environmental performance. Although the point is not discussed in detail, it is clear from the results of the study that any additional thermal plants on the Waikato could strain the river's absorptive capacities severely, unless alternative disposal techniques are used for the various effluents.

Root profile in Multi-layered Dehesas: an approach to plant-to-plant Interaction

Science.gov (United States)

Rolo, V.; Moreno, G.

2009-04-01

size filters in order to avoid fine root loosing. Different plant roots were separated visually. Q. ilex roots were identified by their black cork, pasture roots were white, C. ladanifer roots were dark red and R. spaherocarpa roots were yellow clear. Besides, all them exhibited a different texture. Weight, length, surface and average diameter were measured in each root sample using the WinRHIZOpro program. The results showed a clear rooting pattern, high root density in the first soil layers decreasing in depth, in all the plant strata studied. The coexistence of, at least, two plant stratas modified most of the rooting profiles. In this way, natural grasses growing alone kept 90% of root density in the first 30 cm. In R. sphaerocarpa dehesas pasture reached up to 170 cm although the root density decreased much faster than in C. ladanifer dehesas where pasture had a higher density in the overall profile, but reaching a much lower depth. The introduction of shrubs lowered highly the pasture root density. This effect was higher growing with C. ladanifer than with R. sphaerocarpa, which slightly modified the pasture rooting profile. The effect of trees in the pasture root system was less clear. Trees growing alone stored 70 % of their root density in the first 30 cm. The tree root system reached the deepest soil layer explored in all the profiles. The introduction of shrub reduced highly the tree root density in the first soil layer. This effect was higher in presence of C. ladanifer whose influence reduced 40 % of tree root density in the first soil layer; nevertheless tree root density increased in deep layers when growing with C. ladanifer while it decreased throughout the profile when growing with R. sphaerocarpa. R. sphaerocarpa root system stored less root density in the first soil layer than C. ladanifer, reaching up to 190 cm depth. The influence of the tree increased a 20% the R. sphaerocarpa root density in the first soil layers; however the rest of the profile

Lack of mitochondrial thioredoxin o1 is compensated by antioxidant components under salinity in Arabidopsis thaliana plants.

Science.gov (United States)

Calderón, Aingeru; Sánchez-Guerrero, Antonio; Ortiz-Espín, Ana; Martínez-Alcalá, Isabel; Camejo, Daymi; Jiménez, Ana; Sevilla, Francisca

2018-02-15

In a changing environment, plants are able to acclimate to the new conditions by regulating their metabolism through the antioxidant and redox systems involved in the stress response. Here we studied a mitochondrial thioredoxin in wild type (WT) Arabidopis thaliana and two Attrxo1 mutant lines grown in the absence or presence of 100 mM NaCl. Compared to WT plants, no evident phenotype was observed in the mutant plants in control condition, although they had higher number of stomata, loss of water, nitric oxide and carbonyl protein contents as well as higher activity of superoxide dismutase (SOD) and catalase enzymes than WT plants. Under salinity, the mutants presented lower water loss and higher stomatal closure, H 2 O 2 and lipid peroxidation levels accompanied by higher enzymatic activity of catalase and the different SOD isoenzymes compared to WT plants. These inductions may collaborate in the maintenance of plant integrity and growth observed under saline conditions, possibly as a way to compensate the lack of TRXo1. We discuss the potential of TRXo1 to influence the development of the whole plant under saline conditions, which have great value for the agronomy of plants growing under unfavourable environment. This article is protected by copyright. All rights reserved.

Biological Invasion Influences the Outcome of Plant-Soil Feedback in the Invasive Plant Species from the Brazilian Semi-arid.

Science.gov (United States)

de Souza, Tancredo Augusto Feitosa; de Andrade, Leonaldo Alves; Freitas, Helena; da Silva Sandim, Aline

2017-05-30

Plant-soil feedback is recognized as the mutual interaction between plants and soil microorganisms, but its role on the biological invasion of the Brazilian tropical seasonal dry forest by invasive plants still remains unclear. Here, we analyzed and compared the arbuscular mycorrhizal fungi (AMF) communities and soil characteristics from the root zone of invasive and native plants, and tested how these AMF communities affect the development of four invasive plant species (Cryptostegia madagascariensis, Parkinsonia aculeata, Prosopis juliflora, and Sesbania virgata). Our field sampling revealed that AMF diversity and frequency of the Order Diversisporales were positively correlated with the root zone of the native plants, whereas AMF dominance and frequency of the Order Glomerales were positively correlated with the root zone of invasive plants. We grew the invasive plants in soil inoculated with AMF species from the root zone of invasive (I changed ) and native (I unaltered ) plant species. We also performed a third treatment with sterilized soil inoculum (control). We examined the effects of these three AMF inoculums on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas. We found that I unaltered and I changed promoted the growth of all invasive plants and led to a higher plant dry biomass, mycorrhizal colonization, and P uptake than control, but I changed showed better results on these variables than I unaltered . For plant responsiveness to mycorrhizas and fungal inoculum effect on plant P concentration, we found positive feedback between changed-AMF community (I changed ) and three of the studied invasive plants: C. madagascariensis, P. aculeata, and S. virgata.

Bibliographical review of radioactive cesium uptake capacity and processes in aquatic plants

International Nuclear Information System (INIS)

Pally, Monique; Foulquier, Luc.

1981-11-01

Both freshwater and marine plants are included in this survey covering 217 reports published between 1954 and 1979. These articles involve the radiocesium abundance found in areas either directly or indirectly affected by liquid waste releases. They specify the concentration factors determined from field measurements and laboratory works. Other areas covered include contamination kinetics, radiocesium distribution in higher plants, effects of biological and environmental factors. Radiocesium uptake potential is higher in freshwater algae and plants than in marine algae. Radiocesium adsorption phenomena seem to predominate in algae over absorption, while in the higher freshwater plants absorption is the primary phenomena. In areas not directly affected by liquid wastes, plant activity levels increased until they reached 10000 pCi/kg wet weight in 1965, and reduced thereafter. In areas directly affected by waste discharges, the activity levels range from 10 to 16000 pCi/kg wet weight in seawater, and from practically zero to 230000 pCi/kg in fresh water. This variability also affects the concentration factors. In most cases, the values measured in marine algae range from 10 to 100; the highest radiocesium uptake is found in brown algae and red algae. The concentration factors measured in freshwater mosses and algae are most often around 4000, while they are about 2000 in submerged, floating and emergent plants. Some plants, specially mosses and algae, proved to be better bioindicators than others. The biological half-lives range from 2 to 21 days in marine algae, and from 1 to 65 days in freshwater plants. This survey underscores the necessity of allowing for the ecological characteristics of each site when evaluating the impact of nuclear plants [fr

Transfer-factors for radionuclides in the coal-fired power plants environments in Serbia

International Nuclear Information System (INIS)

Todorovic, Dragana; Jankovic, Marija; Joksic, Jasminka; Radenkovic, Mirjana

2008-01-01

Full text: During the coal combustion in power plants, radionuclides are distributed in solid and gaseous combustion products and discharged into environment. Radioactivity monitoring of coal-fired power-plants environments (PP Nikola Tesla, PP Kolubara, PP Morava and PP Kostolac) in Serbia was carried out during 2003-2006. Here are presented results concerning the soil-plant and ash-plant systems. Plant samples growing at the soil and ash disposals are analyzed by gamma spectrometry (HPGe detector, relative efficiency 23%) and corresponding transfer factors (TF) for natural isotopes 226 Ra, 232 Th and 40 K were calculated and discussed. Obtained concentrations values of naturally occurring radionuclides are in following ranges: (0.4 - 29) Bq/kg 226 Ra, (0.16 - 23) Bq/kg 232 Th, (245 - 1274) Bq/kg 40 K, (1.7 - 30) Bq/kg 238 U, (0.08 - 4.7) Bq/kg 235 U, (5.6 - 95) Bq/kg 210 Pb; (28 - 288) Bq/kg 7 Be and man-made 137 Cs in range 0.06 - 2.8 Bq/kg. Ash-to-plant and soil-to-plant transfer factors for 226 Ra, 232 Th and 40 K are calculated for several sampling points. Values for both ash-to-plant and soil-to-plant transfer factors are much higher for 40 K than 226 Ra and 232 Th probably due to different assimilation mechanisms of these elements by plants. Analyzed radionuclides have higher concentrations in the ash disposal than soil, and corresponding transfer-factors values obtained for ash-plant systems (ranged from 0,007 to 0,179 for 226 Ra, from 0,015 to 0,174 for 232 Th and from 0,418 to 2,230 for 40 K) are higher, indicating that there is no limit value for absorption in plants. (author)

Metabolism of fluoranthene in different plant cell cultures and intact plants

Energy Technology Data Exchange (ETDEWEB)

Kolb, M.; Harms, H.

2000-05-01