Littérature scientifique sur le sujet « Synthetic plants »
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Articles de revues sur le sujet "Synthetic plants"
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Sajid, Moon, Chaitanya N. Channakesavula, Shane R. Stone et Parwinder Kaur. « Synthetic Biology towards Improved Flavonoid Pharmacokinetics ». Biomolecules 11, no 5 (18 mai 2021) : 754. http://dx.doi.org/10.3390/biom11050754.
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Flavonoids are a structurally diverse class of natural products that have been found to have a range of beneficial activities in humans. However, the clinical utilisation of these molecules has been limited due to their low solubility, chemical stability, bioavailability and extensive intestinal metabolism in vivo. Recently, the view has been formed that site-specific modification of flavonoids by methylation and/or glycosylation, processes that occur in plants endogenously, can be used to improve and adapt their biophysical and pharmacokinetic properties. The traditional source of flavonoids and their modified forms is from plants and is limited due to the low amounts present in biomass, intrinsic to the nature of secondary metabolite biosynthesis. Access to greater amounts of flavonoids, and understanding of the impact of modifications, requires a rethink in terms of production, more specifically towards the adoption of plant biosynthetic pathways into ex planta synthesis approaches. Advances in synthetic biology and metabolic engineering, aided by protein engineering and machine learning methods, offer attractive and exciting avenues for ex planta flavonoid synthesis. This review seeks to explore the applications of synthetic biology towards the ex planta biosynthesis of flavonoids, and how the natural plant methylation and glycosylation pathways can be harnessed to produce modified flavonoids with more favourable biophysical and pharmacokinetic properties for clinical use. It is envisaged that the development of viable alternative production systems for the synthesis of flavonoids and their methylated and glycosylated forms will help facilitate their greater clinical application.
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Leydon, Alexander R., Hardik P. Gala, Sarah Guiziou et Jennifer L. Nemhauser. « Engineering Synthetic Signaling in Plants ». Annual Review of Plant Biology 71, no 1 (29 avril 2020) : 767–88. http://dx.doi.org/10.1146/annurev-arplant-081519-035852.
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Synthetic signaling is a branch of synthetic biology that aims to understand native genetic regulatory mechanisms and to use these insights to engineer interventions and devices that achieve specified design parameters. Applying synthetic signaling approaches to plants offers the promise of mitigating the worst effects of climate change and providing a means to engineer crops for entirely novel environments, such as those in space travel. The ability to engineer new traits using synthetic signaling methods will require standardized libraries of biological parts and methods to assemble them; the decoupling of complex processes into simpler subsystems; and mathematical models that can accelerate the design-build-test-learn cycle. The field of plant synthetic signaling is relatively new, but it is poised for rapid advancement. Translation from the laboratory to the field is likely to be slowed, however, by the lack of constructive dialogue between researchers and other stakeholders.
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Gaeta, Robert T., Rick E. Masonbrink, Lakshminarasimhan Krishnaswamy, Changzeng Zhao et James A. Birchler. « Synthetic Chromosome Platforms in Plants ». Annual Review of Plant Biology 63, no 1 (2 juin 2012) : 307–30. http://dx.doi.org/10.1146/annurev-arplant-042110-103924.
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Chruma, Jason J., Douglas J. Cullen, Lydia Bowman et Patrick H. Toy. « Polyunsaturated fatty acid amides from the Zanthoxylum genus – from culinary curiosities to probes for chemical biology ». Natural Product Reports 35, no 1 (2018) : 54–74. http://dx.doi.org/10.1039/c7np00044h.
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Kassaw, Tessema K., Alberto J. Donayre-Torres, Mauricio S. Antunes, Kevin J. Morey et June I. Medford. « Engineering synthetic regulatory circuits in plants ». Plant Science 273 (août 2018) : 13–22. http://dx.doi.org/10.1016/j.plantsci.2018.04.005.
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de Lange, Orlando, Eric Klavins et Jennifer Nemhauser. « Synthetic genetic circuits in crop plants ». Current Opinion in Biotechnology 49 (février 2018) : 16–22. http://dx.doi.org/10.1016/j.copbio.2017.07.003.
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Kołodziejczyk, Marek, Andrzej Oleksy, Bogdan Kulig et Andrzej Lepiarczyk. « Early potato cultivation using synthetic and biodegradable covers ». Plant, Soil and Environment 65, No. 2 (1 février 2019) : 97–103. http://dx.doi.org/10.17221/754/2018-pse.
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The cultivation of plants under the covers made of synthetic polymers brings many benefits, however, it is associated with the need to utilize or recycle these materials after the period of their use. Such problems are not caused by the covers made of natural polymers. The aim of the study carried out in the years 2013–2014 was to determine an effect of covers made of biopolymers and synthetic polymers on thermal conditions and potato yield. Field study was carried out under sandy loam and silty clay loam soils conditions. The temperature of silty clay loam soil under the covers was on average by 2.9°C higher than in the unprotected area, whereas sandy loam soil had the temperature higher by 2.5°C under biodegradable foil and by 2.7°C under standard foil. Temperature increase under non-woven fabrics was lower than under foils. The highest increase in marketable tuber yield after 40 days from emergence and in full maturity of potato plants was found after at application of standard non-woven fabric P17 (7.2 and 7.4 t/ha, respectively) and the lowest, i.e., 3.0 and 3.4 t/ha, respectively, under biodegradable foil. Cover type had no effect on the number of tubers formed on the first harvest date, whereas a significantly higher number of tubers was recorded in the full maturity of plants in the year characterized by a longer growing period of potato under non-woven P17 on sandy loam soil, and under biodegradable foil on silty clay loam soil conditions. A significant influence of cover on the average tuber weight on the first harvest date was found only on sandy loam soil under non-woven fabrics in 2013, as compared to full maturity of plants under biodegradable covers on sandy loam soil in 2013 and on silty clay loam soil under all covers in 2014.
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Motmainna, Mst, Abdul Shukor Juraimi, Muhammad Saiful Ahmad-Hamdani, Mahmudul Hasan, Sabina Yeasmin, Md Parvez Anwar et A. K. M. Mominul Islam. « Allelopathic Potential of Tropical Plants—A Review ». Agronomy 13, no 8 (4 août 2023) : 2063. http://dx.doi.org/10.3390/agronomy13082063.
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The need to meet food demand becomes more urgent as it is forecasted to increase by 50% over the next century. Thus, agronomists promote sensible tools and approaches to eradicate factors that hamper crop production, mainly weeds. The constant use of chemical herbicides to control weeds leads to an increased risk of herbicide-resistant weed populations, environmental pollution, unsafe agricultural products, and negative effects on human health. These problems have caused an interest among researchers to replace synthetic herbicides with alternatives. The purpose of this review was to present the current knowledge base on allelopathic tropical plants and their potential for use in the development of natural product-based, environmentally friendly herbicides for sustainable agriculture, and to stimulate future discussion on this topic. The defence mechanisms of tropical plants have received particular attention because of their potential weed control ability as a natural pesticide that can prevent the overuse of synthetic pesticides. The ancient knowledge of the toxic properties of various tropical plants gives us a basis for creating a novel pest control approach. The synthesis of biopesticides based on allelochemicals opens up the possibility of utilizing natural compounds in crop protection and demonstrates the ability to deal with evolved pesticide resistance.
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Tsygankova Victoria, Anatolyivna, YaV Andrusevich, NM Vasylenko, VM Kopich, SV Popilnichenko, SG Pilyo et VS Brovarets. « Auxin-like and Cytokinin-like Effects of New Synthetic Thienopyrimidine Derivatives on the Growth and Photosynthesis of Wheat ». Journal of Plant Science and Phytopathology 8, no 1 (19 mars 2024) : 015–24. http://dx.doi.org/10.29328/journal.jpsp.1001126.
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The regulatory effect of new synthetic thienopyrimidine derivatives on the growth and photosynthesis of wheat (Triticum aestivum L.) variety Svitlana in the vegetative phase was studied. The regulatory effect of new synthetic thienopyrimidine derivatives was compared with the regulatory effect of auxin IAA (1H-indol-3-yl)acetic acid) or synthetic plant growth regulators Methyur (sodium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine) and Kamethur (potassium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine). After 2 weeks, morphometric parameters (such as average length of shoots and roots (mm), average biomass of 10 plants (g)) and biochemical parameters (such as content of photosynthetic pigments (µg/ml)) of wheat plants grown from seeds treated with synthetic thienopyrimidine derivatives, or auxin IAA, or synthetic plant growth regulators Methyur and Kamethur at a concentration of 10-6M, were measured and compared with similar parameters of control wheat plants grown from seeds treated with distilled water. The regulatory effect of new synthetic thienopyrimidine derivatives on the morphometric and biochemical parameters of wheat plants was similar or higher compared to the regulatory effect of auxin IAA, or synthetic plant growth regulators Methyur and Kamethur. The relationship between the chemical structure of new synthetic thienopyrimidine derivatives and their regulatory effect on the growth and photosynthesis of wheat plants was revealed. The most biologically active thienopyrimidine derivatives are proposed to be used as new synthetic physiological analogues of auxins and cytokinins to improve growth and increase photosynthesis of wheat (Triticum aestivum L.) variety Svitlana in the vegetative phase.
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K. A. Fadhil, T. Suryati et A. Jayanegara. « Comparison Between Natural and Synthetic Antioxidants in Beef Products : A MetaAnalysis ». Jurnal Ilmu Produksi dan Teknologi Hasil Peternakan 11, no 1 (29 janvier 2023) : 19–26. http://dx.doi.org/10.29244/jipthp.11.1.19-26.
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Synthetic antioxidants are created through artificial synthesis, whereas natural antioxidants are created through natural synthesis in plants, animals, and microbes. Although synthetic antioxidants have been used previously, there has been a growing need in recent years for natural antioxidants, largely due to the negative consequences of synthetic antioxidants. Therefore, many current studies have focused on finding natural antioxidants in diverse plants. This study aimed to compare the effectiveness of natural and synthetic antioxidants in beef products using a meta-analysis approach. The method included the stages of identification, selection, and conformity check. The selection process resulted in 12 articles obtained from the electronic database of Harzing’s Publish and Perish software. The metaanalysis model used in this study was random-effect model involving a positive control group (synthetic antioxidants) and an experimental group (natural antioxidants). The effect size and confidence interval were computed using the OpenMEE software, while the summary size and Egger’s test were obtained using JASP software. Results revealed that the addition of natural antioxidants showed comparable quality to synthetic antioxidants, as indicated by similar values between the two groups for the peroxide value, carbonyl content, metmyoglobin content, cooking loss, pH, and hue angle (P>0.05). Natural antioxidants showed a higher value on b (yellowness) and chroma (P<0.05). Parameters indicating lower value (P<0.05) occurred in TBARS, a (redness), and L (lightness). In conclusion, the addition of natural antioxidants in beef products demonstrates comparable results and could be used as alternatives to synthetic antioxidants.
Thèses sur le sujet "Synthetic plants"
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Runguphan, Weerawat. « Reprogramming alkaloid biosynthesis in Catharanthus roseus : synthetic biology in plants ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65274.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
The medicinal plant Madagascar periwinkle (Catharanthus roseus) produces over 130 monoterpene indole alkaloid (MIA) natural products. Many of these compounds have pharmaceutical value, such as the anticancer agents vinblastine and vincristine. Unnatural modifications can impart novel bioactivity to the parent natural product. Advances in synthetic biology and microbial engineering have allowed overproduction of natural products and their analogs in non-native organisms such as yeast and E. coli. However, re-engineering of plant pathways to yield "novel" products has been limited, particularly when compared to the successes achieved in prokaryotic systems. This thesis describes several strategies to re-engineer MIA biosynthesis in periwinkle to produce novel alkaloids. The first strategy involves the introduction of a biosynthetic enzyme with redesigned substrate specificity into periwinkle. The resulting transgenic plant culture produces a variety of unnatural alkaloid compounds when co-cultured with precursors that the re-engineered enzyme has been designed to accept. The second strategy improves upon this work by enabling periwinkle to autonomously synthesize precursor analogs in situ. Specifically, the prokaryotic halogenation machinery was introduced into the genome of periwinkle, which lacks the biosynthetic ability to produce halogenated compounds. These halogenases function within the context of the plant cell to generate halogenated precursor, which is then shuttled into MIA metabolism to yield halogenated alkaloids. Altogether, a new functional group-an organohalide-was introduced into plant secondary metabolism in a regioselective and predictable manner. The third strategy involves RNAi-mediated suppression of MIA biosynthesis in periwinkle. Alkaloid production was obliterated in the resulting transgenic plant culture. The silenced plant culture produces a variety of fluorinated alkaloids when co-cultured with fluorinated starting substrate. The yields of some unnatural alkaloids were improved since the natural precursor was absent. Finally, the fourth strategy describes chemical functionalization of halogenated MIAs. Postbiosynthetic chemical derivatizations of halogenated MIAs using palladium-catalyzed Suzuki-Miyaura cross-coupling reactions robustly afforded aryl and heteroaryl analogs of MIAs. Altogether, the work described in this thesis demonstrates the versatility of medicinal plants in the generation of unnatural alkaloids. Thus, despite their genetic complexity, plants are a viable platform for synthetic biology efforts.
by Weerawat Runguphan.
Ph.D.
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Nworji, Ogechukwu Frances. « Characterisation of transgenic tobacco plants expressing synthetic mouse prion protein ». Thesis, University of East London, 2016. http://roar.uel.ac.uk/5838/.
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The cellular prion protein (PrPC) is a glycoprotein with unknown function constitutively expressed in mammalian neurons. PrPC converts to a pathogenic misfolded isomer (PrPSc) through a poorly understood process, resulting in a group of fatal neurodegenerative diseases collectively known as transmissible spongiform encephalopathy or prion disease. Elucidating the molecular mechanisms behind prion conversion requires production of PrPC in recombinant systems. This study was designed to generate transgenic tobacco plants expressing recombinant mouse prion protein (mPrP). Using a synthetic gene encoding the mouse prion protein, plant expression vectors were constructed for constitutive mPrP expression in the apoplast (pGreen35SmPrP-Apo), cytosol (pGreen35SmPrP-Cyto) and endoplasmic reticulum (pGreen35SmPrP-ER). Putative transgenic plants transformed with either pGreen35SmPrP-Cyto or pGreen35SmPrP-ER were analysed by PCR, ELISA and immunoblot for transgene integration and expression. However, no viable plants were obtained from the pGreen35SmPrP-Apo transformants. ELISA analysis showed that recombinant mPrP accumulated up to 0.0024% of total soluble leaf protein in transgenic tobacco leaves transformed with the pGreen35SmPrP-Cyto construct and 0.0016% of total soluble leaf protein in plants designed to sequester recombinant mPrP to the ER. Furthermore, immunoblot analysis showed that ER-targeted recombinant mPrP was mainly unglycosylated, although a glycosylated mPrP isoform was observed indicating that transgenic tobacco plants process ER-targeted recombinant mPrP in a manner analogous to mammalian systems. The nutrient composition of several transgenic plants were analysed to determine the phenotypic effect of expressing recombinant mPrP in tobacco plants. The analysis revealed that transgenic lines expressing cytosolic-mPrP had elevated average levels of Mn2+ and Fe2+. In addition, kanamycin-treated transgenic plants expressing cytosolic-mPrP developed a non-rooting phenotype. Conversely, the average Cu2+ level was increased in analysed transgenic plants designed to sequester recombinant mPrP in the ER. Furthermore, the plants developed no visible phenotype upon kanamycin treatment. This result support studies that suggest that the PrPC has functional role in metal homeostasis and loss of its thermodynamic structure leads to metal dyshomeostasis which in turn has been linked to prion disease associated neurotoxicity. Finally, the recombinant mPrP was purified via affinity chromatography facilitated by the presence of a C-terminal polyhistidine tag on the synthetic gene constructs.
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Ko, Yuen-yi, et 高婉儀. « Synthetic studies of (-)-curcumol and its related natural products ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31245420.
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Boehm, Christian Reiner. « Gene expression control for synthetic patterning of bacterial populations and plants ». Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267842.
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The development of shape in multicellular organisms has intrigued human minds for millenia. Empowered by modern genetic techniques, molecular biologists are now striving to not only dissect developmental processes, but to exploit their modularity for the design of custom living systems used in bioproduction, remediation, and regenerative medicine. Currently, our capacity to harness this potential is fundamentally limited by a lack of spatiotemporal control over gene expression in multicellular systems. While several synthetic genetic circuits for control of multicellular patterning have been reported, hierarchical induction of gene expression domains has received little attention from synthetic biologists, despite its fundamental role in biological self-organization. In this thesis, I introduce the first synthetic genetic system implementing population-based AND logic for programmed hierarchical patterning of bacterial populations of Escherichia coli, and address fundamental prerequisites for implementation of an analogous genetic circuit into the emergent multicellular plant model Marchantia polymorpha. In both model systems, I explore the use of bacteriophage T7 RNA polymerase as a gene expression engine to control synthetic patterning across populations of cells. In E. coli, I developed a ratiometric assay of bacteriophage T7 RNA polymerase activity, which I used to systematically characterize different intact and split enzyme variants. I utilized the best-performing variant to build a three-color patterning system responsive to two different homoserine lactones. I validated the AND gate-like behavior of this system both in cell suspension and in surface culture. Then, I used the synthetic circuit in a membrane-based spatial assay to demonstrate programmed hierarchical patterning of gene expression across bacterial populations. To prepare the adaption of bacteriophage T7 RNA polymerase-driven synthetic patterning from the prokaryote E. coli to the eukaryote M. polymorpha, I developed a toolbox of genetic elements for spatial gene expression control in the liverwort: I analyzed codon usage across the transcriptome of M. polymorpha, and used insights gained to design codon-optimized fluorescent reporters successfully expressed from its nuclear and chloroplast genomes. For targeting of bacteriophage T7 RNA polymerase to these cellular compartments, I functionally validated nuclear localization signals and chloroplast transit peptides. For spatiotemporal control of bacteriophage T7 RNA polymerase in M. polymorpha, I characterized spatially restricted and inducible promoters. For facilitated posttranscriptional processing of target transcripts, I functionally validated viral enhancer sequences in M. polymorpha. Taking advantage of this genetic toolbox, I introduced inducible nuclear-targeted bacteriophage T7 RNA polymerase into M. polymorpha. I showed implementation of the bacteriophage T7 RNA polymerase/PT7 expression system accompanied by hypermethylation of its target nuclear transgene. My observations suggest operation of efficient epigenetic gene silencing in M. polymorpha, and guide future efforts in chassis engineering of this multicellular plant model. Furthermore, my results encourage utilization of spatiotemporally controlled bacteriophage T7 RNA polymerase as a targeted silencing system for functional genomic studies and morphogenetic engineering in the liverwort. Taken together, the work presented enhances our capacity for spatiotemporal gene expression control in bacterial populations and plants, facilitating future efforts in synthetic morphogenesis for applications in synthetic biology and metabolic engineering.
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Pollak, Williamson Bernardo. « Frameworks for reprogramming early diverging land plants ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273535.
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Plant form is a product of emergent processes of cell division, patterning and morphogenesis. These fundamental processes remain poorly characterised in plants. However, engineering approaches can provide new tools and frameworks for the study and manipulation of plant development. This dissertation describes the development of engineering frameworks for reprogramming of the early diverging land plant Marchantia polymorpha (Marchantia). I describe the generation of genomic and transcriptomic datasets for Marchantia, which has provided the basis for the compilation of a gene-centric registry of DNA parts for engineering (MarpoDB). I describe the development of Loop assembly, an efficient and standardised DNA assembly system based on Type IIS restriction enzymes for recursive fabrication of DNA circuits with high efficiency. MarpoDB was used to mine new DNA parts compatible with Loop assembly which were used to generate plant transformation vectors for labelling of cellular features to study aspects of growth and development. I performed image analysis of genetic markers for segmentation and quantification of cellular properties in germinating gemmae. I implemented high-efficiency Cas9-mediated mutagenesis in Marchantia for use in functional molecular genetics studies. Furthermore, I produced inducible systems for expression of heterologous elements by transactivation which showed negligible levels of basal activity. It was possible to use this system for induction of gene expression in single cells. Finally, these new frameworks were applied to study the gametophytic meristem in Marchantia gemmae. I mapped the expression of several putative candidate homologues for higher plant meristem regulators, performed overexpression and loss-of-function studies for homologues of WUSCHEL, CLAVATA3 and SHOOT MERISTEMLESS. A strategy for misregulation of endogenous genes was developed using inducible transactivation, and was used with cellular markers for WUSCHEL and CLAVATA3 homologues in Marchantia.
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Cowin, Linda Marie. « Some stereochemical and synthetic studies in serrulatane diterpenoid chemistry / ». Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phc8737.pdf.
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Marsian, Johanna. « Transient expression of poliovirus-like particles in plants : developing a synthetic polio vaccine ». Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/62929/.
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Plants, or cell suspension cultures derived from them, are a promising platform for the production of biologics and pharmaceuticals. In this work transient expression utilising the pEAQ vector system was deployed for the expression of virus-like particles (VLPs) in Nicotiana benthamiana or N. tabacum BY-2 cell suspension cultures. The results presented in this thesis demonstrate the potential of plant systems for the production of VLP-based vaccines. VLPs of the fish virus, Nervous necrosis virus (NNV), were successfully produced in plants by transient expression of the coat protein. The protein self-assembled into T = 3 particles, which appeared to be morphologically identical to the wild-type NNV when analysed by high resolution microscopy but were devoid of nucleic acid. In addition, transgenic BY-2 cell suspension lines were generated expressing correctly assembled NNV VLPs. Poliovirus (PV)-like particles from all three PV serotypes, containing either the wt coat protein or coat proteins with stabilising mutations, were successfully expressed in plants. These were generated by co-expression of the structural polyprotein P1 and the proteinase 3CD. Sufficient quantities of purified particles could be obtained for structural and immunological analysis. Mice carrying the gene for the human PV receptor were protected from wild-type PV when immunised with the plant-made stabilised PV VLPs. Structural analysis of the stabilised mutant of PV3 at 3.6 Å resolution revealed a structure almost indistinguishable from wild-type PV3, with the stabilising mutations having no effective on the antigenic surface of the particle. To make the product more attractive to the vaccine industry, tobacco BY-2 cells have been successfully tested for the transient expression of the above-mentioned PV mutant VLPs using the cell-pack method.
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Mbaebie, Oyedemi B. O. « Antiplasmid and antimicrobial activities of synthetic and natural products from selected medicinal plants ». Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1468641/.
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This PhD thesis is part of ongoing project to identify plant natural products and selected synthetic compounds that possess antimicrobial properties; and are able to promote plasmid loss or interfere with bacterial conjugation. The conjugative broad host plasmids investigated include PKM101 (Inc N), TP114 (Inc I2), PUB307 (Inc P), and low- copy number plasmids: R6K (Inc X), R7K (Inc W) and R1-drd-19 (Inc F11). They represented the incompatibility plasmid groups that are currently associated with gross dissemination of antibiotic resistance in bacteria. A series of plant extracts evaluated at sub-inhibitory concentration of 100 mg/L, were shown to inhibit bacterial plasmid conjugation and their active constituents were isolated and characterised. Mallotus philippinensis yielded rottlerin and red compound, with good to moderate antibacterial activity against multidrug resistant Staphylococcus aureus strains, and had a broad range inhibition against the resistant plasmids. Investigation of extracts from the resin of Cannabis sativa L. identified tetrahydrocannabinolic acid (THCA) and cannabinolic acid (CBNA) which in addition to two synthetic cannabinoids: cannabigerol and olivetol inhibited the conjugal transfer of TP114 between E. coli strains. The antiplasmid activities of Δ9-THC, CBN, CBD, significantly reduced the transfer of amoxicillin–resistance conferring PKM 101. Methanolic extract from the dried fruits of Evodia rutaecarpa yielded evodiamine, rutaecarpine and naturally-isolated sucrose. Rutaecarpine was the most active alkaloid against NorA-expressing SA1199B and XU212 strain expressing TetK efflux mechanism. Evodiamine and sucrose had lesser antibacterial effect as well as low level of inhibition against the plasmids. Rutaecarpine and evocarpine remarkably reduced the transfer frequency of PKM 101, showing a high 2 level effect of inhibition by the compound. The bioassay-guided analysis of Capsicum annuum L. yielded capsaicin and dihydrocapsaicin (DHC) which demonstrated moderate antibacterial activities but inhibited conjugal transfer of R-plasmids actively. Capsaicin exhibited a broad range antiplasmid activity while DHC showed selective inhibition. The effect of synthetic compounds that were assessed: ferulenol, 6-gingerol and 6-shogoal were twice as effective against the transfer of PKM 101, TP114 and PUB307 compared to capsaicin, while nonivamide had no remarkable activity. With the exception of promethazine, capsaicin and dihydrocapsaicin that showed some interaction with DNA due to decreased fluorescence which suggests binding, the rest of the compounds: rottlerin, red compound, ferulenol, evocarpine, rutaecarpine, 6-gingerol, 6-shogaol and nonivamide did not bind to DNA. This may indicate other probable mechanism of antiplasmid action of the compounds. Together, some of these compounds were notable for their dual properties: robust antistaphylococcal activity and a broad host range antiplasmid effect, and are reported for the very first time. Such potentials are valuable in the discovery of next generation antimicrobial drugs.
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Tanner, T. M. « An investigation of the interactions of the androgen receptor with a non-steroidal compound and two synthetic progestins ». Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52683.
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Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: The aim of this thesis was to define the interactions of the androgen receptor (AR) with an analog of a non-steroidal plant compound, Compound A (CpdA), as well as two synthetic progestins, medroxyprogesterone acetate (MPA) and norethindrone acetate (NET-A). The data presented indicates that CpdA has antiandrogenic properties, as it represses androgen-induced activation of both specific and non-specific androgen-responsive reporter constructs. It was found that CpdA exerts these effects by a mechanism other than competition with androgen for binding to the ligand-binding domain (LBD) of the receptor. On the other hand, it is demonstrated that both MPA and NET-A compete with androgen for binding to the AR and induce partial agonist activity via the receptor. Using mammalian two-hybrid assays it was revealed that CpdA, similar to anti-androgenic compounds that are able to compete with androgens for binding to the receptor, represses the androgen-induced interaction between the NH2- and COOH-terminals of the AR (N/C-interaction) without competing for binding to the LBD. Furthermore, it was shown that CpdA slightly represses the androgen-dependent recruitment of steroid receptor co-activator 1 (SRC1) to the activation function (AF2) domain of the AR. When the effects of MPA and NET-A on the N/C-interaction were studied, intriguing results were obtained. NET-A, as expected, induced this AR agonist-induced interaction. MPA, however, repressed this AR agonist-induced interaction, an effect previously associated with anti-androgenic activity, despite displaying partial agonist activity in transctivation experiments. On the other hand, both MPA and NET-A induced the interaction between SRC1 and the AF2 domain. In additional experiments with CpdA, it was found that CpdA did not affect the recruitment of SRC1 to the AF1 domain of the receptor; neither did it influence the constitutive activity of the NH2-terminal domain. The anti-androgenic activities of CpdA were confirmed by the toxic effect that this compound had on the androgen-dependent lymph node carcinoma of the prostate (LNCaP) cell-line as well as its ability to repress the androgen-induced expression of the prostate specific antigen (PSA) protein. Taken together, the results presented in this thesis, in combination with the knowledge available on AR function, contribute to an improved understanding of AR function. Furthermore, the importance of defining the precise mechanism by which individual compounds exert their effects is highlighted. In this regard it is demonstrated that two compounds (MPA and NET-A) that display partial agonist activity, can exert their effects via different mechanisms at the molecular level. Detecting such differences in the molecular mechanisms of action could facilitate the improved design of progestins as well as aid clinicians and their patients in selecting the best method of contraception. Lastly, the insights gained into the mechanisms of the anti-androgenic action of CpdA could be useful in therapeutic drug design for diseases, such as prostate cancer, that have an androgen-dependent etiology.
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis was om die interaksies van die androgeen reseptor (AR) met ‘n analoog van ‘n nie-steroiediese plant verbinding, Verbinding A (VbgA), sowel as met twee sintetiese progestogene, medroksiprogesteroon asetaat (MPA) en noretiendroon asetaat (NET-A), te definieer. Die data verskaf dui daarop dat VbgA anti-androgeniese eienskappe besit deurdat dit androgeen-gei'nduseerde aktivering van beide spesifieke- en nie-spesifieke androgeen-responsiewe rapporteerderkonstrukte onderdruk. VbgA veroorsaak hierdie effekte deur ‘n meganisme wat nie kompetisie met androgeen vir binding aan die ligand-bindingsdomein (LBD) van die reseptor behels nie. In teenstelling hiermee word getoon dat beide MPA en NET-A kompeteer met androgeen vir binding aan die AR en gedeeltelike agonistiese aktiwiteit induseer via hierdie reseptor. Deur gebruik to maak van ‘n soogdier twee-hibried essai word getoon dat VbgA, soos ander anti-androgeniese verbindings wat kompeteer met androgeen vir binding aan die reseptor, die androgeen-gei'nduseerde interaksies tussen die NH2- en COOH-terminale van die AR (N/C-interaksie) onderdruk, sonder om te kompeteer vir binding aan die LBD. Daarby is dit bewys dat VbgA die androgeenafhanklike werwing van steroied reseptor ko-aktiveerde 1 (SRC1) na die aktiverings funksie (AF2) domein van die AR gedeeltelik onderdruk. Die studie van die effekte van MPA en NET-A op die N/C-interaksie het interessante resultate opgelewer. NETA, soos verwag, het hierdie AR agonis-gei'nduseerde interaksie geinduseer. MPA, aan die ander kant, het hierdie AR agonis-gei'nduseerde interaksie onderdruk, ‘n effek wat tevore met anti-androgeniese aktiwiteit geassosieer is, al het die transaktiveringseksperimente daarop gedui dat MPA ‘n AR agonis is. Aan die ander kant, het beide MPA en NET-A die interaksie tussen SRC1 en die AF2 domein geinduseer. In addisionele eksperimente met VbgA is gevind dat VbgA geen effek het op die werwing van SRC1 na die AF1 domein van die reseptor nie en ook geen invloed het op die konstitutiewe aktiwiteit van die NHh-terminaal domein nie. VbgA se antiandrogeniese eienskappe is bevestig deur die toksiese effekte op die androgeenafhanklike limfknoop karsinoom van die prostaat (LNCaP) sellyn sowel as deur sy vermoe om die androgen-gei'nduseerde uitdrukking van die prostaat spesifieke antigeen (PSA) protei'en te onderdruk. Die resultate aangebied in hierdie tesis, in kombinasie met die beskikbare kennis oor AR funksie, dra by tot ‘n verbeterde kennis van AR funksionering. Verder word die belang van die definiering van die meganisme waardeur individuele verbindings hulle effekte veroorsaak, getoon. In hierdie verband is getoon dat twee verbindings (MPA en NET-A), wat gedeeltelike agonistiese aktiwiteit besit, hulle effekte via verskillende meganismes op die molekulere vlak veroorsaak. Deur hierdie verskille in die molekulere meganismes van aksie uit te wys, kan beter progestogene ontwikkel word, en verder sal dit vir dokters en hul pasiente help om die beste voorbehoedmiddel te kies. Laastens, die insig wat verkry is ten opsigte van die meganismes van anti-androgeniese aktiwiteit van VbgA mag nuttig wees in die ontwerp van terapeutiese middels vir die behandeling van siektetoestande met androgeen-afhanklikke etiologie (bv. prostaatkanker).
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Brundin, Carl. « Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society ». Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-146831.
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This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.
Livres sur le sujet "Synthetic plants"
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Rao, V. S. Sundara. Vegetable and synthetic tanning materials. Madras : Indian Leather, 1991.
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Hess, Ronald Wayne. Potential production cost benefit of constructing and operating first-of-a-kind synthetic fuel plants. Santa Monica, CA : Rand Corp., 1985.
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Knoepffler, Nikolaus. Grüne Gentechnik und synthetische Biologie - keine Sonderfälle. Freiburg : Verlag Karl Alber, 2013.
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Krichko, A. A., et N. G. Fonskai͡a. Pererabotka ugleĭ i avtomatizat͡sii͡a tekhnologicheskikh prot͡sessov : Sbornik nauchnykh trudov IGI. Moskva : IOTT, 1987.
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Office, General Accounting. Synthetic fuels : Status of the Great Plains Coal Gasification Project, August 1, 1985 : report to the Congress of the United States. Washington, D.C : The Office, 1985.
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C, Budd George, et AWWA Research Foundation, dir. Evaluation of MIEX : Process impacts on different source waters. Denver, CO : Awwa Research Foundation, 2005.
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Office, General Accounting. Synthetic fuels : Status of the Great Plains Coal Gasification Project : fact sheet for the Chairman, Subcommittee on Energy and Power, Committee on Energy and Commerce, House of Representatives. Washington, D.C : The Office, 1987.
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Office, General Accounting. Synthetic fuels : Comparative analyses of retaining and selling the Great Plains project : report to the chairman, Subcommittee on Energy and Power, Committee on Energy and Commerce, House of Representatives. Washington, D.C : The Office, 1988.
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Clarkson, Wensley. Legal highs : Inside secrets of the world's newest and deadliest drugs. London : Quercus, 2015.
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Office, General Accounting. Synthetic fuels : Analysis of DOE's estimate of the sale value of the Great Plains project : report to the chairman, Subcommittee on Energy and Power, Committee on Energy and Commerce, House of Representatives. Washington, D.C : The Office, 1988.
Trouver le texte intégralChapitres de livres sur le sujet "Synthetic plants"
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Fourné, Franz. « Special Processes and Plants ». Dans Synthetic Fibers, 525–94. München, Germany : Carl Hanser Verlag GmbH & Co. KG, 1999. http://dx.doi.org/10.1007/978-3-446-40133-4_5.
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Fourné, Franz. « Auxiliary Plants and Equipment ». Dans Synthetic Fibers, 595–641. München, Germany : Carl Hanser Verlag GmbH & Co. KG, 1999. http://dx.doi.org/10.1007/978-3-446-40133-4_6.
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Fourné, Franz. « Special Processes and Plants ». Dans Synthetic Fibers, 525–94. München : Carl Hanser Verlag GmbH & ; Co. KG, 1999. http://dx.doi.org/10.3139/9783446401334.005.
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Fourné, Franz. « Auxiliary Plants and Equipment ». Dans Synthetic Fibers, 595–641. München : Carl Hanser Verlag GmbH & ; Co. KG, 1999. http://dx.doi.org/10.3139/9783446401334.006.
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Micheli, Maurizio, et Carla Benelli. « Synthetic Seeds of Two Aquatic Plants ». Dans Synthetic Seeds, 233–39. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-24631-0_9.
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Dudley, Quentin M., Oleg Raitskin et Nicola J. Patron. « Cas9-Mediated Targeted Mutagenesis in Plants ». Dans Plant Synthetic Biology, 1–26. New York, NY : Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-1791-5_1.
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Bibik, Jacob D., Abigail E. Bryson et Björn Hamberger. « Compartmentalized Terpenoid Production in Plants Using Agrobacterium-Mediated Transient Expression ». Dans Synthetic Biology, 21–34. New York, NY : Springer US, 2024. http://dx.doi.org/10.1007/978-1-0716-3658-9_2.
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Sharma, Neelam, R. Gowthami et Ruchira Pandey. « Synthetic Seeds : A Valuable Adjunct for Conservation of Medicinal Plants ». Dans Synthetic Seeds, 181–216. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-24631-0_7.
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Sareen, P. K., J. B. Chowdhury et V. K. Chowdhury. « Amphidiploids/Synthetic Crop Species ». Dans Distant Hybridization of Crop Plants, 62–81. Berlin, Heidelberg : Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84306-8_5.
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Lukan, Tjaša, Kristina Gruden et Anna Coll. « Plant X-tender Toolbox for the Assembly and Expression of Multiple Transcriptional Units in Plants ». Dans Plant Synthetic Biology, 81–97. New York, NY : Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-1791-5_5.
Texte intégralActes de conférences sur le sujet "Synthetic plants"
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Mosqueira Furtado, Renato Andrade, André Luís Marques Marcato et Ivo Chaves da Silva Junior. « Generation of Synthetic Series for Hydroelectric Plants in Brazilian Interconnected System by Metaheuristic ». Dans 2024 59th International Universities Power Engineering Conference (UPEC), 1–6. IEEE, 2024. https://doi.org/10.1109/upec61344.2024.10892424.
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Komakhin, R. A., L. N. Efremova et S. R. Strelnikova. « Effective synthetic regulatory elements based on natural DNA polymorphism of plant gene promoters ». Dans IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-223.
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Feldhoff, Jan Fabian, Kai Schmitz, Markus Eck, Lars Schnatbaum-Laumann, Doerte Laing, Francisco Ortiz-Vives et Jan Schulte-Fischedick. « Comparative System Analysis of Direct Steam Generation and Synthetic Oil Parabolic Trough Power Plants With Integrated Thermal Storage ». Dans ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54345.
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Parabolic trough power plants are currently the most commercially applied systems for CSP power generation. To improve their cost-effectiveness, one focus of industry and research is the development of processes with other heat transfer fluids than the currently used synthetic oil. One option is the utilization of water/steam in the solar field, the so-called direct steam generation (DSG). Several previous studies promoted the economic potential of DSG technology [1–3]. Analyses’ results showed that live steam parameters of up to 500°C and 120 bars are most promising and could lead to a reduction of the levelized electricity cost (LEC) of about 11% [4]. However, all of these studies only considered plants without thermal energy storage (TES). Therefore, a system analysis including integrated TES was performed by Flagsol GmbH and DLR together with Solar Millennium AG, Schott CSP GmbH and Senior Bergho¨fer GmbH, all Germany. Two types of plants are analyzed and compared in detail: a power plant with synthetic oil and a DSG power plant. The design of the synthetic oil plant is very similar to the Spanish Andasol plants [5] and includes a molten salt two-tank storage system. The DSG plant has main steam parameters of 500 °C and 112 bars and uses phase change material (PCM) for the latent and molten salt for the sensible part of the TES system. To enable comparability, both plants share the same gross electric turbine capacity of 100 MWel, the same TES capacity of nine hours of full load equivalent and the same solar multiple of the collector field of about two. This paper describes and compares both plants’ design, performance and investment. Based on these results, the LEC are calculated and the DSG plant’s potential is evaluated. One key finding is that with currently proposed DSG storage costs, the LEC of a DSG plant could be higher than those of a synthetic oil plant. When considering a plant without TES on the other hand, the DSG system could reduce the LEC. This underlines the large influence of TES and the still needed effort in the development of a commercial storage system for DSG.
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Tsygankova, V., I. Voloshchuk, Ya Andrusevich, S. Pilyo et V. Brovarets. « Study of the growth-stimulating properties of pyrimidine derivatives on sugar sorghum (Sorghum saccharatum L.) variety Zubr ». Dans international scientific-practical conference. MYKOLAYIV NATIONAL AGRARIAN UNIVERSITY, 2024. http://dx.doi.org/10.31521/978-617-7149-78-0-47.
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The growth-stimulating properties of synthetic pyrimidine derivatives on sugar sorghum (Sorghum saccharatum L.) variety Zubr grown for 2 weeks in laboratory conditions were studied. The morphometric indicators of sorghum plants treated with an aqueous 10-6 M solution of pyrimidine derivatives were compared with the indicators of sorghum plants treated with an aqueous 10-6 M solution of synthetic plant growth regulators Ivin, Methyur, Kamethur and phytohormone auxin IAA. Control sorghum plants were treated with distilled water. Conducted studies have shown that synthetic pyrimidine derivatives exhibit stimulating properties on the growth and development of shoots and roots of sorghum plants similar to auxin IAA, or Ivin, Methyur and Kamethur. Under the influence of synthetic pyrimidine derivatives, the morphometric indicators of sorghum plants increased significantly: the average length of shoots (mm), the average length of roots (mm), the average biomass (g) of 10 plants, compared to similar indicators of control sorghum plants. The relationship between the chemical structure and growth-stimulating properties of synthetic pyrimidine derivatives was analyzed. The use of the most biologically active synthetic compounds to stimulate the growth of sugar sorghum (Sorghum saccharatum L.) variety Zubr during the growing season is proposed
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Helac, Vahid, Selma Hanjalic, Selma Grebovic et Vedad Becirovic. « Synthetic Inertia in Wind Power Plants : An Overview ». Dans 2023 22nd International Symposium INFOTEH-JAHORINA (INFOTEH). IEEE, 2023. http://dx.doi.org/10.1109/infoteh57020.2023.10094115.
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Teng, Fei, et Goran Strbac. « Evaluation of Synthetic Inertia Provision from Wind Plants ». Dans 2015 IEEE Power & Energy Society General Meeting. IEEE, 2015. http://dx.doi.org/10.1109/pesgm.2015.7285969.
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Giuffrida, Mario Valerio, Hanno Scharr et Sotirios A. Tsaftaris. « ARIGAN : Synthetic Arabidopsis Plants Using Generative Adversarial Network ». Dans 2017 IEEE International Conference on Computer Vision Workshop (ICCVW). IEEE, 2017. http://dx.doi.org/10.1109/iccvw.2017.242.
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Khamidullina, L. A., P. D. Tobysheva, E. A. Rybina, O. E. Cherepanova et A. V. Pestov. « Plant growth biostimulants based on synthetic polyaminosaccharides ». Dans 2nd International Scientific Conference "Plants and Microbes : the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.117.
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Ghosh, Manik, Siva Mavuduru, Preeti Awasthi et Ajay Timiri. « Computer Aided Prespective for Selection of Medicinal Plants Against Viruses ». Dans The 18th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland : MDPI, 2014. http://dx.doi.org/10.3390/ecsoc-18-e004.
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Weerakoon, Tharindra, Nisshaptha Nadarajah, Ramlah Rizwan, Rithmi Ranathunga et Janani Vithanage. « In Silico Comparison of Drug-Likeness of Phytochemicals from Nine Herbal Plants against Asthma ». Dans International Electronic Conference on Synthetic Organic Chemistry. Basel Switzerland : MDPI, 2022. http://dx.doi.org/10.3390/ecsoc-26-13527.
Texte intégralRapports d'organisations sur le sujet "Synthetic plants"
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Katan, Jaacov, et Michael E. Stanghellini. Clinical (Major) and Subclinical (Minor) Root-Infecting Pathogens in Plant Growth Substrates, and Integrated Strategies for their Control. United States Department of Agriculture, octobre 1993. http://dx.doi.org/10.32747/1993.7568089.bard.
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In intensive agriculture, harmful soilborne biotic agents, cause severe damage. These include both typical soilborne (clinical) major pathogens which destroy plants (e.g. Fusarium and Phytophthora pathogens), and subclinical ("minor") pathogens (e.g. Olpidium and Pythium). The latter cause growth retardation and yield decline. The objectives of this study were: (1) To study the behavior of clinical (major) and subclinical (minor) pathogens in plant growth substrate, with emphasis on zoosporic fungi, such as Pythium, Olipidium and Polymyxa. (2) To study the interaction between subclinical pathogens and plants, and those aspects of Pythium biology which are relevant to these systems. (3) To adopt a holistic-integrated approach for control that includes both eradicative and protective measures, based on a knowledge of the pathogens' biology. Zoospores were demonstrated as the primary, if not the sole propagule, responsible for pathogen spread in a recirculating hydroponic cultural system, as verified with P. aphanidermatum and Phytophthora capsici. P. aphanidermatum, in contrast to Phytophthora capsici, can also spread by hyphae from plant-to-plant. Synthetic surfactants, when added to the recirculating nutrient solutions provided 100% control of root rot of peppers by these fungi without any detrimental effects on plant growth or yield. A bacterium which produced a biosurfactant was proved as efficacious as synthetic surfactants in the control of zoosporic plant pathogens in the recirculating hydroponic cultural system. The biosurfactant was identified as a rhamnolipid. Olpidium and Polymyxa are widespread and were determined as subclinical pathogens since they cause growth retardation but no plant mortality. Pythium can induce both phenomena and is an occasional subclinical pathogen. Physiological and ultrastructural studies of the interaction between Olpidium and melon plants showed that this pathogen is not destructive but affects root hairs, respiration and plant nutrition. The infected roots constitute an amplified sink competing with the shoots and eventually leading to growth retardation. Space solarization, by solar heating of the greenhouse, is effective in the sanitation of the greenhouse from residual inoculum and should be used as a component in disease management, along with other strategies.
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Mosquna, Assaf, et Sean Cutler. Systematic analyses of the roles of Solanum Lycopersicum ABA receptors in environmental stress and development. United States Department of Agriculture, janvier 2016. http://dx.doi.org/10.32747/2016.7604266.bard.
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Drought and other abiotic stresses have major negative effects on agricultural productivity. The plant hormone abscisic acid (ABA) regulates many responses to environmental stresses and can be used to improve crop performance under stress. ABA levels rise in response to diverse abiotic stresses to coordinate physiological and metabolic responses that help plants survive stressful environments. In all land plants, ABA receptors are responsible for initiating a signaling cascade that leads to stomata closure, growth arrest and large-scale changes in transcript levels required for stress tolerance. We wanted to test the meaning of root derived ABA signaling in drying soil on water balance. To this end we generated transgenic tomato lines in which ABA signaling is initiated by a synthetic agonist- mandipropamid. Initial study using a Series of grafting experiments indicate that that root ABA signaling has no effect on the immediate regulation of stomata aperture. Once concluded, these experiments will enable us to systematically dissect the physiological role of root-shoot interaction in maintaining the water balance in plants and provide new tools for targeted improvement of abiotic stress tolerance in crop plants.
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Brasington, Robert D., John L. Haslback, Norma J. Kuehn, Eric G. Lewis, Lora L. Pinkerton, Marc J. Turner, Elsy Varghese et Mark Woods. Cost and Performance Baseline for Fossil Energy Plants - Volume 2 : Coal to Synthetic Natural Gas and Ammonia. Office of Scientific and Technical Information (OSTI), juillet 2011. http://dx.doi.org/10.2172/1515254.
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Chen, Yona, Jeffrey Buyer et Yitzhak Hadar. Microbial Activity in the Rhizosphere in Relation to the Iron Nutrition of Plants. United States Department of Agriculture, octobre 1993. http://dx.doi.org/10.32747/1993.7613020.bard.
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Iron is the fourth most abundant element in the soil, but since it forms insoluble hydroxides at neutral and basic pH, it often falls short of meeting the basic requirements of plants and microorganisms. Most aerobic and facultative aerobic microorganisms possess a high-affinity Fe transport system in which siderophores are excreted and the consequent Fe complex is taken up via a cognate specific receptor and a transport pathway. The role of the siderophore in Fe uptake by plants and microorganisms was the focus of this study. In this research Rhizopus arrhizus was found to produce a novel siderophore named Rhizoferrin when grown under Fe deficiency. This compound was purified and its chemical structure was elucidated. Fe-Rhizoferrin was found to alleviate Fe deficiency when applied to several plants grown in nutrient solutions. It was concluded that Fe-Rhizoferrin is the most efficient Fe source for plants when compared with other among microbial siderophores known to date and its activity equals that of the most efficient synthetic commercial iron fertilizer-Fe EDDHA. Siderophores produced by several rhizosphere organisms including Rhizopus Pseudomonas were purified. Monoclonal antibodies were produced and used to develop a method for detection of the siderophores produced by plant-growth-promoting microorganisms in barley rhizosphere. The presence of an Fe-ferrichrome uptake in fluorescent Pseudomonas spp. was demonstrated, and its structural requirements were mapped in P. putida with the help of biomimetic ferrichrome analogs. Using competition experiments, it was shown that FOB, Cop B and FC share at least one common determinant in their uptake pathway. Since FC analogs did not affect FOB or Cop-mediated 55Fe uptake, it could be concluded that these siderophores make use of a different receptor(s) than FC. Therefore, recognition of Cop, FOB and FC proceeds through different receptors having different structural requirements. On the other hand, the phytosiderophores mugineic acid (MA and DMA), were utilized indirectly via ligand exchange by P. putida. Receptors from different biological systems seem to differ in their structural requirements for siderophore recognition and uptake. The design of genus- or species-specific drugs, probes or chemicals, along with an understanding of plant-microbe and microbe-microbe relationships as well as developing methods to detect siderophores using monoclonal antibodies are useful for manipulating the composition of the rhizosphere microbial population for better plant growth, Fe-nutrition and protection from diseases.
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Skone, Timothy J. Cost and Performance Baseline for Fossil Energy Plants - Volume 2 : Coal to Synthetic Natural Gas and Ammonia (Presentation). Office of Scientific and Technical Information (OSTI), juillet 2011. http://dx.doi.org/10.2172/1526312.
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Raghothama, Kashchandra G., Avner Silber et Avraham Levy. Biotechnology approaches to enhance phosphorus acquisition of tomato plants. United States Department of Agriculture, janvier 2006. http://dx.doi.org/10.32747/2006.7586546.bard.
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Abstract: Phosphorus is one of the least available macronutrient in the soil. The high affinity phosphate transporters are known to be associated with phosphate acquisition under natural conditions. Due to unique interactions of phosphate with soil particles, up to 80% of the applied phosphates may be fixed forcing the farmers to apply 4 to 5 times the fertilizers necessary for crop production. Efficient uptake and utilization of this essential nutrient is essential for sustainability and profitability of agriculture. Many predictions point to utilization/exhaustion of high quality phosphate rocks within this century. This calls for efforts to improve the ability of plants to acquire and utilize limiting sources of phosphate in the rhizosphere. Two important molecular and biochemical components associated with phosphate efficiency are phosphate transporters and phosphatases. This research project is aimed at defining molecular determinants of phosphate acquisition and utilization in addition to generating phosphate uptake efficient plants. The main objectives of the project were; Creation and analysis of transgenic tomato plants over-expressing phosphatases and transporters Characterization of the recently identified members (LePT3 and LePT4) of the Pi transporter family Generate molecular tools to study genetic responses of plants to Pi deficiency During the project period we have successfully identified and characterized a novel phosphate transporter associated with mycorrhizal symbiosis. The expression of this transporter increases with mycorrhizal symbiosis. A thorough characterization of mutant tomato lacking the expression of this gene revealed the biological significance of LePT3 and another novel gene LePT4. In addition we have isolated and characterized several phosphate starvation induced genes from tomato using a combination of differential and subtractive mRNA hybridization techniques. One of the genes, LePS2 belongs to the family of phospho-protein phosphatase. The functionality of the recombinant protein was determined using synthetic phosphor-peptides. Over expression of this gene in tomato resulted in significant changes in growth, delay in flowering and senescence. It is anticipated that phospho-protein phosphatase may have regulatory role in phosphate deficiency responses of plants. In addition a novel phosphate starvation induced glycerol 3-phosphate permease gene family was also characterized. Two doctoral research students are continuing the characterization and functional analysis of these genes. Over expression of high affinity phosphate transporters in tobacco showed increased phosphate content under hydroponic conditions. There is growing evidence suggesting that high affinity phosphate transporters are crucial for phosphate acquisition even under phosphate sufficiency conditions. This project has helped train several postdoctoral fellows and graduate students. Further analysis of transgenic plants expressing phosphatases and transporters will not only reveal the biological function of the targeted genes but also result in phosphate uptake and utilization efficient plants.
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Loebenstein, Gad, William Dawson et Abed Gera. Association of the IVR Gene with Virus Localization and Resistance. United States Department of Agriculture, août 1995. http://dx.doi.org/10.32747/1995.7604922.bard.
Texte intégralRésumé :
We have reported that localization of TMV in tobacco cultivars with the N gene, is associated with a 23 K protein (IVR) that inhibited replication of several plant viruses. This protein was also found in induced resistant tissue of Nicotiana glutinosa x Nicotiana debneyi. During the present grant we found that TMV production is enhanced in protoplasts and plants of local lesion responding tobacco cultivars exposed to 35oC, parallel to an almost complete suppression of the production of IVR. We also found that IVR is associated with resistance mechanisms in pepper cultivars. We succeeded to clone the IVR gene. In the first attempt we isolated a clone - "101" which had a specific insert of 372 bp (the full length gene for the IVR protein of 23 kD should be around 700 bp). However, attempts to isolate the full length gene did not give clear cut results, and we decided not to continue with this clone. The amino acid sequence of the N-terminus of IVR was determined and an antiserum was prepared against a synthetic peptide representing amino acids residues 1-20 of IVR. Using this antiserum as well as our polyclonal antiserum to IVR a new clone NC-330 was isolated using lamba-ZAP library. This NC-330 clone has an insert of about 1 kB with an open reading frame of 596 bp. This clone had 86.6% homology with the first 15 amino acids of the N-terminal part of IVR and 61.6% homology with the first 23 amino acids of IVR. In the QIA expression system and western blotting of the expressed protein, a clear band of about 21 kD was obtained with IVR antiserum. This clone was used for transformation of Samsun tobacco plants and we have presently plantlets which were rooted on medium containing kanamycin. Hybridization with this clone was also obtained with RNA from induced resistant tissue of Samsun NN but not with RNA from healthy control tissue of Samsun NN, or infected or healthy tissue of Samsun. This further strengthens the previous data that the NC 330 clone codes for IVR. In the U.S. it was shown that IVR is induced in plants containing the N' gene when infected with mutants of TMV that elicit the HR. This is a defined system in which the elicitor is known to be due to permutations of the coat protein which can vary in elicitor strength. The objective was to understand how IVR synthesis is induced after recognition of elicitor coat protein in the signal transduction pathway that leads to HR. We developed systems to manipulate induction of IVR by modifying the elicitor and are using these elicitor molecules to isolate the corresponding plant receptor molecules. A "far-western" procedure was developed that found a protein from N' plants that specifically bind to elicitor coat proteins. This protein is being purified and sequenced. This objective has not been completed and is still in progress. We have reported that localization of TMV in tobacco cultivars with the N gene, is associated with a 23 K protein (IVR) that inhibited replication of several plant viruses. This protein was also found in induced resistant tissue of Nicotiana glutinosa x Nicotiana debneyi.
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Dolja, Valerian V., Amit Gal-On et Victor Gaba. Suppression of Potyvirus Infection by a Closterovirus Protein. United States Department of Agriculture, mars 2002. http://dx.doi.org/10.32747/2002.7580682.bard.
Texte intégralRésumé :
The plant virus family Polyviridae is the largest and most destructive of all plant viruses. Despite the continuous effort to develop resistant plant varieties, there is a desperate need for novel approaches conferring wide-range potyvirus resistance. Based on experiments with the tobacco etch potyvirus (TEV)-derived gene expression vector, we suggested approach for screening of the candidate resistance genes. This approach relies on insertion of the genes into a virus vector and evaluation of the phenotypes of the resulting recombinant viruses. The genes which suppress infection by the recombinant virus are selected as candidates for engineering transgenic resistance. Our analysis of the TEV variants expressing proteins of the beet yellows closterovirus (BYV) revealed that one of those, the leader proteinase (L-Pro), strongly and specifically interfered with the hybrid TEV infection. Since closterovirus L-Pro is evolutionary related to potyviral helper component-proteinase (HC-Pro), we suggested that the L-Pro interfered with HC-Pro function via a trans-dominant inhibitory effect. Based on these findings, we proposed to test two major hypotheses. First, we suggested that L-Pro-mediated suppression of potyvirus infection is a general phenomenon effective against a range of potyviruses. The second hypothesis stated that the suppression effect can be reproduced in transgenic plants expressing L-Pro, and can be utilized for generation of resistance to potyviruses. In accord with these hypotheses, we developed two original objectives of our proposal: A) to determine the range of the closterovirus-derived suppression of potyviral infection, and B) to try and utilize the L-Pro-mediated suppression for the development of transgenic resistance to potyviruses. In the first phase of the project, we have developed all major tools and technologies required for successful completion of the proposed research. These included TEV and ZYMV vectors engineered to express several closteroviral L-Pro variants, and generation of the large collection of transgenic plants. To our satisfaction, characterization of the infection phenotypes exhibited by chimeric TEV and ZYMV variants confirmed our first hypothesis. For instance, similar to TEV-L- Pro(BYV) chimera, ZYMV-L-Pro(LIYV) chimera was debilitated in its systemic spread. In contrast, ZYMV-GUS chimera (positive control) was competent in establishing vigorous systemic infection. These and other results with chimeric viruses indicated that several closteroviral proteinases inhibit long-distance movement of the potyviruses upon co-expression in infected plants. In order to complete the second objective, we have generated ~90 tobacco lines transformed with closteroviral L-Pro variants, as well as ~100 lines transformed with BYV Hsp70-homolog (Hsp70h; a negative control). The presence and expression of the trans gene in each line was initially confirmed using RT-PCR and RNA preparations isolated from plants. However, since detection of the trans gene-specific RNA can not guarantee production of the corresponding protein, we have also generated L-Pro- and Hsp70h-specific antisera using corresponding synthetic peptides. These antisera allowed us to confirm that the transgenic plant lines produced detectable, although highly variable levels of the closterovirus antigens. In a final phase of the project, we tested susceptibility of the transgenic lines to TEV infection. To this end, we determined that the minimal dilution of the TEV inoculum that is still capable of infecting 100% of nontransgenic plants was 1:20, and used 10 plants per line (in total, ~2,000 plants). Unfortunately, none of the lines exhibited statistically significant reduction in susceptibility. Although discouraging, this outcome prompted us to expand our experimental plan and conduct additional experiments. Our aim was to test if closteroviral proteinases are capable of functioning in trans. We have developed agroinfection protocol for BYV, and tested if co- expression of the L-Pro is capable of rescuing corresponding null-mutant. The clear-cut, negative results of these experiments demonstrated that L-Pro acts only in cis, thus explaining the lack of resistance in our transgenic plants. We have also characterized a collection of the L-Pro alanine- scanning mutants and found direct genetic evidence of the requirement for L-Pro in virus systemic spread. To conclude, our research supported by BARD confirmed one but not another of our original hypotheses. Moreover, it provided an important insight into functional specialization of the viral proteinases and generated set of tools and data with which we will be able to address the molecular mechanisms by which these proteins provide a variety of critical functions during virus life cycle.
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Reisch, Bruce, Avichai Perl, Julie Kikkert, Ruth Ben-Arie et Rachel Gollop. Use of Anti-Fungal Gene Synergisms for Improved Foliar and Fruit Disease Tolerance in Transgenic Grapes. United States Department of Agriculture, août 2002. http://dx.doi.org/10.32747/2002.7575292.bard.
Texte intégralRésumé :
Original objectives . 1. Test anti-fungal gene products for activity against Uncinula necator, Aspergillus niger, Rhizopus stolonifer and Botrytis cinerea. 2. For Agrobacterium transformation, design appropriate vectors with gene combinations. 3. Use biolistic bombardment and Agrobacterium for transformation of important cultivars. 4. Characterize gene expression in transformants, as well as level of powdery mildew and Botrytis resistance in foliage of transformed plants. Background The production of new grape cultivars by conventional breeding is a complex and time-consuming process. Transferring individual traits via single genes into elite cultivars was proposed as a viable strategy, especially for vegetatively propagated crops such as grapevines. The availability of effective genetic transformation procedures, the existence of genes able to reduce pathogen stress, and improved in vitro culture methods for grapes, were combined to serve the objective of this proposal. Effective deployment of resistance genes would reduce production costs and increase crop quality, and several such genes and combinations were used in this project. Progress The efficacy of two-way combinations of Trichoderma endochitinase (CHIT42), synthetic peptide ESF12 and resveratrol upon the control of growth of Botrytis cinerea and Penicillium digitatum were evaluated in vitro. All pairwise interactions were additive but not synergistic. Per objective 2, suitable vectors with important gene combinations for Agrobacterium transformation were designed. In addition, multiple gene co-transformation by particle bombardment was also tested successfully. In New York, transformation work focused on cultivars Chardonnay and Merlot, while the technology in Israel was extended to 41B, R. 110, Prime, Italia, Gamay, Chardonnay and Velika. Transgenic plant production is summarized in the appendix. Among plants developed in Israel, endochitinase expression was assayed via the MuchT assay using material just 1-5 days after co-cultivation. Plants of cv. Sugraone carrying the gene coding for ESF12, a short anti-fungal lytic peptide under the control of the double 358 promoter, were produced. Leaf extracts of two plants showed inhibition zones that developed within 48 h indicating the inhibitory effect of the leaf extracts on the six species of bacteria. X fastidiosa, the causal organism of Pierce's disease, was very sensitive to leaf extracts from ESF12 transformed plants. Further work is needed to verify the agricultural utility of ESF12 transformants. In New York, some transformants were resistant to powdery mildew and Botrytis fruit rot. Major conclusions, solutions, achievements and implications The following scientific achievements resulted from this cooperative BARD project: 1. Development and improvement of embryogenesis and tissue culture manipulation in grape, while extending these procedures to several agriculturally important cultivars both in Israel and USA. 2. Development and improvement of novel transformation procedures while developing transformation techniques for grape and other recalcitrant species. 3. Production of transgenic grapevines, characterization of transformed vines while studying the expression patterns of a marker gene under the control of different promoter as the 35S CaMV in different part of the plants including flowers and fruits. 4. Expression of anti-fungal genes in grape: establishment of transgenic plants and evaluation of gene expression. Development of techniques to insert multiple genes. 5. Isolation of novel grape specific promoter to control the expression of future antimicrobial genes. It is of great importance to report that significant progress was made in not only the development of transgenic grapevines, but also in the evaluation of their potential for increased resistance to disease as compared with the non engineered cultivar. In several cases, increased disease resistance was observed. More research and development is still needed before a product can be commercialized, yet our project lays a framework for further investigations.
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Granot, David, Scott Holaday et Randy D. Allen. Enhancing Cotton Fiber Elongation and Cellulose Synthesis by Manipulating Fructokinase Activity. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7613878.bard.
Texte intégralRésumé :
a. Objectives (a) Identification and characterization of the cotton fiber FRKs; (b) Generating transgenic cotton plants overproducing either substrate inhibited tomato FRK or tomato FRK without substrate inhibition; (c) Generating transgenic cotton plants with RNAi suppression of fiber expressed FRKs; (d) Generating Arabidopsis plants that over express FRK1, FRK2, or both genes, as additional means to assess the contribution of FRK to cellulose synthesis and biomass production. b. Background to the topic: Cellulose synthesis and fiber elongation are dependent on sugar metabolism. Previous results suggested that FRKs (fructokinase enzymes that specifically phosphorylate fructose) are major players in sugar metabolism and cellulose synthesis. We therefore hypothesized that increasing fructose phosphorylation may enhance fiber elongation and cellulose synthesis in cotton plants. Accordinlgy, the objectives of this research were: c. Major conclusions and achievements: Two cotton FRKs expressed in fibers, GhFRK2 and GhFRK3, were cloned and characterized. We found that GhFRK2 enzyme is located in the cytosol and GhFRK3 is located within plastids. Both enzymes enable growth on fructose (but not on glucose) of hexose kinase deficient yeast strain, confirming the fructokinase activity of the cloned genes. RNAi constructs with each gene were prepared and sent to the US collaborator to generate cotton plants with RNAi suppression of these genes. To examine the effect of FRKs using Arabidopsis plants we generated transgenic plants expressing either LeFRK1 or LeFRK2 at high level. No visible phenotype has been observed. Yet, plants expressing both genes simultaneously are being created and will be tested. To test our hypothesis that increasing fructose phosphorylation may enhance fiber cellulose synthesis, we generated twenty independent transgenic cotton plant lines overexpressing Lycopersicon (Le) FRK1. Transgene expression was high in leaves and moderate in developing fiber, but enhanced FRK activity in fibers was inconsistent between experiments. Some lines exhibited a 9-11% enhancement of fiber length or strength, but only one line tested had consistent improvement in fiber strength that correlated with elevated FRK activity in the fibers. However, in one experiment, seed cotton mass was improved in all transgenic lines and correlated with enhanced FRK activity in fibers. When greenhouse plants were subjected to severe drought during flowering and boll development, no genotypic differences in fiber quality were noted. Seed cotton mass was improved for two transgenic lines but did not correlate with fiber FRK activity. We conclude that LeFRK1 over-expression in fibers has only a small effect on fiber quality, and any positive effects depend on optimum conditions. The improvement in productivity for greenhouse plants may have been due to better structural development of the water-conducting tissue (xylem) of the stem, since stem diameters were larger for some lines and the activity of FRK in the outer xylem greater than observed for wild-type plants. We are testing this idea and developing other transgenic cotton plants to understand the roles of FRK in fiber and xylem development. We see the potential to develop a cotton plant with improved stem strength and productivity under drought for windy, semi-arid regions where cotton is grown. d. Implications, scientific and agricultural: FRKs are probably bottle neck enzymes for biomass and wood synthesis and their increased expression has the potential to enhance wood and biomass production, not only in cotton plants but also in other feed and energy renewable plants.