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1
Menges, Margit. "Synchronisation of Arabidopsis cell suspension cultures". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620602.
Testo completo
2
Green, Martha Alexandra. "Apoplastic ascorbate metabolism in rose cell suspension cultures". Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/14944.
Testo completoAbstract (sommario):
Endogenous intraprotoplasmic ascorbate in rose cell suspension cultures as a model system ranged from 0.05 mmol kg-1 in 0-d-old cultures to 1.1 mmol kg-1 in 5-d-old cultures. Apoplastic ascorbate was estimated as 0.5 and 8 μM in 0- and 5-d-old cultures respectively, indicating that ascorbate is endogenous to, and may be metabolised within, the apoplast. Exogenous (apoplastic) 1 mM L-[1-14C]ascorbate was almost completely consumed (metabolised and/or taken up) by rose cultures within 8 hours of administration. Total 14C was removed from medium but slower than ascorbate. The calculated concentration of metabolites of ascorbate showed that metabolites were formed in the medium and then removed from the medium in 5-d-old cultures. Removal of metabolites could be due to either uptake by or binding to cells. The nature of the metabolites of 0.5 mM [1-14C]ascorbate was examined in 5-d-old rose culture and spent medium by electrophoresis at pH 6.5. Ascorbate was metabolised both enzymically in spent medium and non-enzymically in boiled spent medium. Three 14C-metabolites were identified as dehydroascorbate, diketogulonate and oxalate. Other acidic 14C-metabolites (C, D, E and F) have not as yet been identified. F is highly mobile during electrophoresis at pH 2.0, showing that it has a low pK. C, D and E are also mobile at pH 2.0 but less so than F. E and C are interconvertible non-enzymically during storage and can E be regenerated by treatment with NaOH, suggesting that C is a lactone of E. 14C-F was converted to [14C]oxalate by whole culture and by spent medium but not by boiled spent medium, indicating an enzyme-catalysed reaction. The enzyme was partially inhibited by 100 mM azide but not by antioxidants. [14C]Oxalate was produced from 14C-F by alkali hydrolysis indicating the presence of an oxalyl ester group. The metabolism of apoplastic ascorbate, described in this thesis, is very different from its intraprotoplasmic metabolism. I have identified novel metabolites and propose a novel pathway for the metabolism of apoplastic ascorbate.
3
Chakrabortee, Sohini. "Characterisation of cytokinin responses in arabidopsis cell suspension culture". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613927.
Testo completo
4
Smith, Rachel C. "Xyloglucan endotransglycosylation in the apoplast of plant cell suspension cultures". Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/12139.
Testo completoAbstract (sommario):
Xyloglucan is thought to form cross-links between cellulose microfibrils within the plant cell wall. The hydrolysis of these 'tethers' may be involved in wall loosening, and a control of cell expansion. Transglycosylation reactions between xyloglucan 'tethers' has for some years been suggested as an alternative mechanism to hydrolysis by which the plant cell wall may be loosened. The work described in this thesis is an investigation of this hypothesis. Spinach (Spinacia oleracea L.) cell suspension cultures were incubated with [xylosyl-3H]xyloglucan nonasaccharide (XG9; Glc4.Xyl3.Gal.Fuc) and [reducing terminus-3H]XG9. The majority of 3H-labelled material remained soluble and extracellular (69-98% ), and 53-57% of it underwent an apparent increase in molecular weight as shown by gel permeation chromatography. This result could suggest the occurrence of a transglycosylation reaction in the apoplast. A proportion of XG9 was hydrolysed to low molecular weight 3H-labelled products. [3H]-XG9 was found to have undergone no appreciable re-arrangementon incorporation into the high molecular weight product as complete acid hydrolysis and Driselase digestion released similar 3H-labelled hydrolysis products from the putative transglycosylation product, as from [3H]-XG9. The reducing terminus of the oligosaccharide remained as a reducing terminus of the high molecular weight product. This was shown by sodium borohydride reduction of the product formed during incubation of cells with [reducing terminus-3H]XG9. This would suggest that XG9 acts as the acceptor substrate, an apoplastic donor being cleaved and the newly formed potentially reducing terminus of this polymer being transferred onto XG9.
5
Eberhardt, Thomas Leonard. "Characterization of lignin deposition in Pinus taeda L. cell suspension cultures". Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-07282008-134210/.
Testo completo
6
Athwal, Gurdeep Singh. "Glutamate dehydrogenase, its role, regulation and characterisation in carrot cell suspension cultures". Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307584.
Testo completo
7
Van, der Westhuizen Andries P. P. "The evaluation of solids suspension in a pilot scale mechanical flotation cell". Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/5390.
Testo completoAbstract (sommario):
Includes bibliographical references.The central step in flotation is particle collection, with solids suspension together with gas dispersion and reagent mixing as necessary preconditions for particle collection. Solids suspension is therefore often identified as an important subprocess for effective flotation. Yet, surprisingly little work has been published on solids suspension in mechanical flotation cells, especially more recent studies since the advent of round mechanical flotation cells and the subsequent dramatic increases in maximum cell sizes are largely lacking.
8
Riley, Bryan Scott. "The Suspension Cultivation of, and the use of Alternative Cell lines for the In Vitro Cultivation of, Treponema Pallidum Subspecies Pallidum". Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc798117/.
Testo completoAbstract (sommario):
This study had two objectives: to achieve suspension cultivation of Sf1Ep cells and to develop procedures for achieving the replication of T. pallidum in those cell cultures. Sf1Ep cells have been the sole cell line used for the in vitro cultivation of T. pallidum. A study was undertaken to determine if other cell lines can support growth of T. pallidum. Rabbit skin fibroblasts (RAB-9), nude mouse ear (NME) cells, and normal rebbit testis fibroblasts (RT) were compared to Sf1Ep cells for their ability to support in vitro multiplication of T. pallidum. RAB-9 cells supported multiplication of treponemes equal to that of Sf1Ep cells. NME and RT cells also supported growth but to a lesser extent than Sf1Ep cells. Utilization of alternative cell lines may lead to improved in vitro growth of T. pallidum including possible serial passage.
9
Kang, Jane. "Migration of blood cells in non-uniform suspension for a dialyzer design". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53871.
Testo completoAbstract (sommario):
Hemodialysis is a renal replacement therapy that removes waste solutes from the blood stream using concentration gradients across a membrane. In order to overcome several shortcomings and increase the waste removal rate, a new dialyzer (filter) design is proposed in this study. In the new dialyzer design, the blood concurrently flows with a sheath fluid in a micro-fluidic channel. Because the blood stream directly contacts the sheath stream, it is important to prevent blood cell migration from the blood stream to the sheath stream while providing enough time for the waste solutes to diffuse into the sheath stream. This research was intended to understand the migration behavior of red blood cells (RBC) and platelets in non-uniform suspension flow, where the blood and sheath flows in direct contact, and apply the results to identify the feasible design space of the proposed dialyzer.
The effect of different flow conditions and channel geometry on the blood cell extraction ratios (ER), the ratio of cells lost into the sheath stream, in non-uniform suspension flows was parametrically studied using Lattice Boltzmann and Spectrin Link (LB-SL) method based direct numerical simulation (DNS). Analyzing ER over the flow distance showed that the channel size and the area ratio of sheath to channel are the main variables that affect the ER. Based on the relationship found, a meta-model of RBC ER was created, although platelet ERs showed only a general trend. Based on the study, feasible conditions that will retain blood cells in the blood stream were identified.
Then, the DNS results of blood cell ER were used with a molecule diffusion model and a hemodialysis system model to study the feasibility of the proposed dialyzer design that maximizes middle molecule filtration with limited blood cell and protein loss. No feasible design was found in the studied range suggesting that relying purely on the diffusion based on the direct contact for the removal of middle molecules is not a feasible solution with the small channel size (~700 µm) due to the loss of protein. It suggested that in order to increase the middle molecule removal while maintain the protein level, clearance ratio of middle molecule to protein should be increased using large channel size, small sheath stream thickness, long tubule length, and slow blood flow velocity.
The intellectual merit of this research lies in understanding the migration behavior of blood cells in a non-uniform suspension. This knowledge helped to establish the feasibility of the proposed dialyzer design and can be applied in a variety of applications for the manipulation of cells in a micro-fluidic channel.
10
Waldbillig, David. "Aqueous suspension plasma spraying of yttria stabilized zirconia solid oxide fuel cell electrolytes". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27910.
Testo completoAbstract (sommario):
In order to meet increasing world energy demand in a sustainable manner, clean and
efficient new energy technologies need to be developed. Fuel cells have been proposed as a potential energy conversion technology to help facilitate this transition to cleaner energy. Solid oxide fuel cells (SOFC) in particular are thought to be a practical, near term clean energy technology; however, current state-of-the-art wet ceramic fabrication techniques make SOFC manufacturing labour-intensive, fairly expensive and difficult to automate, and the high firing temperatures required limit the usable materials sets and increase production times. Plasma spraying (PS) is a potential next generation SOFC fabrication process that can rapidly produce fully sintered ceramic layers without the need for post deposition heat treatments; however, it is difficult to produce the thin, fully dense layers required for SOFC electrolytes using conventional plasma spray techniques, as the carrier gas based feeding configurations
typically require large feedstock powders. Suspension plasma spraying (SPS) is a
modification of conventional PS processes that uses micron or sub-micron sized feedstock
powders suspended in a carrier liquid. SPS has the potential to significantly improve coating quality and microstructural control. Thus plasma spray manufacturing methods may have the ability to both reduce cell fabrication and material costs and improve cell performance, making them an important step toward successful SOFC commercialization.
This project investigated the properties of metal supported aqueous SPS yttria stabilized
zirconia (YSZ) layers that could be used as SOFC electrolytes and developed a thorough understanding of the relationships between the base layers (substrate and cathode),
suspension and plasma spraying parameters and the resulting coating properties. Using this understanding, plasma sprayed full cells (cathode, electrolyte and anode) with optimized electrolyte microstructures with 96% density were produced and
electrochemically tested. The measured open circuit voltage values were approximately 90% of the Nernst voltages, and electrolyte area specific resistances below 0.1 Ω cm² were
obtained at 750⁰C for electrolyte thicknesses below 20 μm. Least-squares fitting was used to estimate the contributions of the YSZ bulk material, its microstructure, and the contact resistance to the measured series resistance values.
11
Moraes, Trevor F. "Purification and characterization of phosphoenolpyruvate carboxylase from Brassica napus (canola) suspension cell cultures". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0001/MQ42669.pdf.
Testo completo
12
Åslund, Ingrid, Samo Lasič, Agnieszka Nowacka, Markus Nilsson e Daniel Topgaard. "Measuring molecular exchange for water in a yeast cell suspension through NMR diffusometry". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190551.
Testo completo
13
Åslund, Ingrid, Samo Lasič, Agnieszka Nowacka, Markus Nilsson e Daniel Topgaard. "Measuring molecular exchange for water in a yeast cell suspension through NMR diffusometry". Diffusion fundamentals 11 (2009) 69, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14035.
Testo completo
14
Kerr, Ellen M. "The synthesis, wall-binding and breakdown of hemicelluloses in maize cell-suspension cultures". Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/12355.
Testo completoAbstract (sommario):
A method was developed to separate protoplasmic contents from the cell wall causing polymer degradation. Alkali treatment (6 M NaOH at 37°C) was shown then to solubilise essentially all remaining (wall-bound) 3H-polymers. Gel-permeation chromatography (GPC) on Sepharose CL-4B was used to size-fractionate the isolated 3H-polymers. Alkali treatments, similar to those employed to extract wall-bound 3H-hemicellulose, were found to minimise aggregation of xylan and xyloglucan caused by sample storage and such treatments were applied to 3H-polymers from each of the cell compartments. GPC-fractionated 3H-polymers was Driselase-digested to diagnostic 3H-fragments; maximisation of [3H]xylan susceptibility to Driselase required an acid pre-treatment. The data presented illustrate the synthesis and subsequent secretion of 3H-polymers from the protoplasm to the cell wall, where they become integrated before subsequent degradation or sloughing to the culture medium. Protoplasmic [3H]xylan and [3H]xyloglucan were polymerised from 40 kDa to 2 MDa before secretion to the cell wall, where the hemicelluloses further increased in size in over 2 MDa. Within the medium, [3H]xylan and [3H]xyloglucan were approximately 1-2 MDa until 2 d after the onset of 3H-labelling, when they dramatically increased in size, probably due to phenolic coupling. The Mr values observed were much higher than reported for rose hemicellulose (Thompson and Fry, 1997). Attempts to ‘disaggregate’ the very high-Mr wall-bound 3H-hemicelluloses, using different GPC eluents, alkali and enzymic digestion, were unsuccessful. Alkali, however, was successful in ‘disaggregating’ the very high-Mr soluble extracellular [3H]xylan and [3H]xyloglucan, suggesting that alkali-labile bonds, more resistant than feruloyl esters, play a significant part in the extracellular cross-linking of xylan and xyloglucan. The in vivo formation of high-Mr complexes of soluble extracellular 3H-polysaccharides xyloglucan. The in vivo formation of high-Mr complexes of soluble extracellular 3H-polysaccharides (SEPs) was delayed by sinapic acid, chlorogenic acid and rutin but promoted by ferulic acid and tyrosine: these data support a role for phenolic groups in the extracellular cross-linking of hemicelluloses.
15
Lagares, Lemos Miguel. "Matlab Based Specific Impedance Spectroscopy Simulator for Suspension of Cells". Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19348.
Testo completoAbstract (sommario):
By means of the analytical formula of specific impedance for the spherical cells in suspensionintroduced by Kenneth S. Cole in 1928, a bioimpedance simulator has been developed for thegeneration of specific impedance spectrums of suspension of cells. With the help of the simulatorthe user can obtain different impedance spectrums according with the biophysical parameters ofthe cell suspension. Then, generate different kind of plots in order to understand and interpret allthe resulting information.With the selection of different values and range of the biophysical parameters to obtain thespectrums, it is possible to simulate different kinds of physiological process and observe theirelectrical bioimpedance behaviour in a certain range of frequencies. The performance of thesimulator has been validated simulating Cellular Edema and Haemorrhage has been alsosimulated.
16
Nealey, Luke T. "The isolation, characterization, and biological testing of xyloglucan from suspension cultured lobloly pine cell spent medium". Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/5749.
Testo completo
17
Zandstra, Peter William. "Cytokine-dependent regulation of human hematopoietic cell self-renewal and differentiation in suspension cultures". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25194.pdf.
Testo completo
18
Montgomery, Sarah Lynn. "Impedance measurement system for embryonic stem cell and embryoid body cultures". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24661.
Testo completo
19
Byers, Susan D., e University of Lethbridge Faculty of Arts and Science. "Stimulation of microsomal diacylglycerol acyltransferase activity from microspore-derived cell suspension cultures of oilseed rape". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1999, 1999. http://hdl.handle.net/10133/101.
Testo completoAbstract (sommario):
Several factors including an unidentified endogenous substance were found to stimulate microsomal diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) from a microspore-derived cell suspension culture of oilseed rape (Brassica napus L. cv Jet Neuf). Mg2+ salts were found to stimulate microsomal DGAT 14 to 23-fold. ATP and CoA were also found to stimulate the enzyme 2.4 and 12 fold respectively, although the effects were decreased in the presence of high Mg2+ concentrations. While microsomal DGAT activity was only slightly increased by the concentration of exogenous diacylglycerol in the reaction mixture it was increased substantially by the addition of exogenous phosphatidate. Other phospholipids tested were not found to have this stimulatory effect. During attempts to investigate possible covalent modification of the enzyme, the soluble fraction obtained from cell suspension homogenate was found to contain a small metastable organic molecule(s) which stimulated DGAT activity. Stimulation of microsomal DGAT by this factor was concentration dependent but not dependent on preincubation time.xiii, 95 leaves : ill. ; 28 cm.
20
Gerasymenko, Iryna. "Molecular cloning, heterologous expression and characterization of strictosidine glucosidase from Rauvolfia serpentina cell suspension cultures". [S.l.] : [s.n.], 2002. http://ArchiMeD.uni-mainz.de/pub/2002/0036/diss.pdf.
Testo completo
21
Byers, Susan D. "Stimulation of microsomal diacylglycerol acyltransferase activity from microspore-derived cell suspension cultures of oilseed rape". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0016/MQ49143.pdf.
Testo completo
22
Alyousuf, Saeed Habib Hassan. "Comparison of free amino acid profiles in carrot cell suspension cultures resistant to stress conditions". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184631.
Testo completoAbstract (sommario):
Plant cells resistant to specific amino acid analogs have been reported to accumulate the corresponding free amino acids. The purpose of this study was to determine the concentrations of fifteen free amino acids: alanine, valine, leucine, isoleucine, glutamate, proline, arginine, aspartate, threonine, methionine, lysine, serine, glycine, tryptophan and phenylalanine in Daucus carota cell lines, resistant either to the proline analog azetidine-2 carboxylic acid (A2C), or to the tryptophan analog 5-methyltryptophan (5-MT), or to both the analogs combined. This study also intended to determine if these analogs influence the biosynthesis of the above-mentioned fifteen amino acids in the cell line resistant to A2C and 5-MT. Carrot cell lines resistant to 5-MT, to A2C, or to both the analogs were selected by incubating carrot cells in liquid growth media containing either 0.3 mM 5-MT, or 0.5 mM A2C for 6 to 16 weeks. Free amino acid concentrations were then determined in the extracts of the cells. Resistance to 5-MT resulted in significant increases in the intracellular concentrations of tryptophan, phenylalanine, leucine, valine, isoleucine, and proline. Resistance to A2C resulted in significant increase in proline only. Resistance to both the analogs caused increases in proline, lysine, phenylalanine, and tryptophan concentrations. In the cell line resistant to both the analogs, the treatment with 5-MT caused increases in leucine, proline, aspartate, threonine, lysine, and tryptophan. The treatment with A2C caused increases in isoleucine, arginine, threonine, methionine, lysine, and glycine, whereas treatment with both the analogs caused increases in threonine, lysine, phenylalanine, and tryptophan. These results indicate the possibility of a common biosynthetic control of a number of amino acids in carrot cells, resembling that found in microorganisms. It is also evident from the results that the analogs play an active role in the biosynthesis of amino acids in the resistant cell lines.
23
Lam, Ming-Chi. "In silico dynamic optimisation studies for batch/fed-batch mammalian cell suspension cultures producing biopharmaceuticals". Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/45465.
Testo completoAbstract (sommario):
Mammalian cell cultures are valuable for synthesis of therapeutic proteins and antibodies. They are commonly cultivated in bioindustry in form of large-scale suspension fed-batch cultures. The structure and regulatory responses of mammalian cells are complex, making it challenging to model them for practical process optimisation. The adjustable degrees of freedom in the cell cultures can be continuous variables as well as binary-type variables. The binary-type variables may be irreversible in cases such as cell-cycle arrest. The main aim of this study was to develop a general model for mammalian cell cultures using extracellular variables and capturing major changes in cellular responses between batch and fed-batch cultures. The model development started with a simple model for a hybridoma cell culture using first-principle equations. The growth kinetics was only linked to glucose and glutamine and the cell population was divided into three cell-cycle phases to study the phenomenon of cell-cycle arrest. But there were certain deficiencies in predicting growth rates in the death phase in fed-batch cultures although it was successful to simultaneously optimise a combination of continuous and binary-irreversible degrees of freedom. Thus, the growth kinetics was further related to amino acids concentration and cellular responses to high versus low concentration of glutamine and glucose based on a Chinese hamster ovary cell-line where amino acids data were available. The model contained 192 parameters with 26 measured cell culture variables. Most of the sensitive parameters were able to be identified using the Sobol' method of Global Sensitivity Analysis. The model could capture the main trends of key variables and be used to search for the optimal working range of the controllable variables. But uncertainties in the sensitive model parameters caused non-negligible variations in the model-based optimisation results. It is recommended to couple such off-line optimisation with on-line measurements of a few major variables to tackle the real-time uncertain nature of the complex cell culture system.
24
Davoren, Jonathan M., e University of Lethbridge Faculty of Arts and Science. "Gene expression in a microspore-derived cell suspension culture of Brassica Napus exhibiting enhanced oil production". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1997, 1997. http://hdl.handle.net/10133/345.
Testo completoAbstract (sommario):
Triacylglycerol (TAG) production in the microspore derived (MD) cell
suspension culture ofBrassica napus L. cv Jet Neuf was enhanced when the sucrose
concentration in the growth medium was increased from 2 to 14 % (w/v). mRNA
differential display by polymerase chain reaction was used to examine gene expression in
cells grown at different sucrose concentrations in order to identify mRNAs which
could be associated with oil formation. The anchored primer, T12AA, was used to screen
one subset, representing approximately one twelfth of the transcript population, isolated
from cultures grown in media supplemented to 2, 6 and 14 % (w/v) sucrose. Analysis of
this mRNA subset revealed thirteen cDNAs which appeared to be upregulated as the
sucrose concentration was increased. Cloning and sequencing revealed multiple cDNA
fragments for each signal detected by differential display. RT-PCR analysis of sixteen
different cDNAs revealed that eight encoded mRNAs which were upregulated in parallel
to the increase in media sucrose. Comparison of the eight upregulated cDNAs to other
sequences in GenBank revealed the following: (1) BSS8A had a 100% identity with the
last 25 amino acids of an acyl carrier protein from Arabidopsis thaliana, (2) BSS1A
displayed homology to a number of sequences of unknown function, (3) BSS1 IB
displayed weak but significant homology to a number of sequences of unknown function,
(4) BSS13A displayed homology to four members of the thioredoxin family from ,4.
thaliana and (5) four Had no significant homology to previously reported sequences
which makes them potential candidates to encode lipogenic enzymes. These results
indicate that differential display of mRNA may be a simple and rapid method for the
identification of sucrose-modulated gene expression changes in this system and for the
characterization of novel sequences potentially encoding lipogenic proteins.xxi, 256 leaves : ill. ; 28 cm.
25
Chang, Yu-Hsiang David. "Augmentation of mass transfer through electrical means and nutrient enrichment for suspension and entrapment cell cultures". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/33503.
Testo completo
26
Hao, Dong-Yun. "Studies on nicotine N-demethylation in cell suspension cultures of Nicotiana tabacum L cv. Wisconsin-38". Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/13992.
Testo completoAbstract (sommario):
Radioactive feeding experiments, in which DL-[pyrrolidine-2'-14C]-nicotine was added to 10 day old cultures, confirmed that the kinetic pattern of this N-demethylation was similar to that of non-radioactive nicotine, and that nornicotine was the major product and was produced intracellularly with a maximum percentage conversion of approximately 70%. The appearance of nornicotine paralleled the disappearance of the added nicotine, although small amounts of four other radioactive-metabolites were observed. One of these metabolites was tentatively identified by GC-MS as N-formyl-3-nornicotine. The properties of (-)-nornicotine produced from (-)-nicotine by 10 day old cell cultures were determined using both, polarimetry and chiral gas chromatography. The results obtained, which were convincingly consistent, showed that the nornicotine produced was exclusively one enantiomer. This provided strong evidence that the bioconversion of nicotine by tobacco cultures does not involve opening of the pyrrolidine ring. It is possible that the mechanism of nicotine bioconversion by cultured cells might differ from that proposed for the plant, in which a partially racemized mixture of (+)- and (-)-nornicotine has been reported. This could be the result of the opening and closing of the pyrrolidine ring during bioconversion. A radioactive enzyme assay procedure developed, using cell-free preparations of tobacco cell cultures, has shown for the first time that the enzyme(s) which catalyses this N-demethylation is present in tobacco. The enzyme(s), which has been fully characterised, has a Km of 7.4μM and a Vmax of 7.6 x 10-2pKat and appears to be NADPH dependent. Subcellular fractionation of the homogenate using isopycnic differential centrifugation, together with TEM, showed that most of the enzyme activity was present in the intermediate pellet whilst the maximum specific activity appeared to be associated with the microsomal fraction. Also, the addition of selected possible methyl group acceptors, i.e. putrescine, glycine and ethanolamine, to either dialysed or undialysed enzyme preparations, did not promote enzyme activity, suggesting that the N-demethylation is unlikely to be a transmethylation but satisfies some of the primary criteria for cytochrome P-450 involvement. Studies involving Sephadex G-25 gel fractionation showed that molecules smaller than 5,000MW are not involved in this nicotine N-demethylation. Finally, the possible enzymatic mechanism involved in this N-demethylation is discussed.
27
Toubal, Malika. "Caractérisation ultrasonore de milieux biologiques en suspension : application aux hématies". Valenciennes, 1996. https://ged.uphf.fr/nuxeo/site/esupversions/0adf1de9-0c5e-4d57-b4c8-ff9d51b13204.
Testo completoAbstract (sommario):
Notre travail porte sur la caractérisation ultrasonore de suspensions d'hématies à travers l'analyse de l'atténuation et de la vitesse de propagation dans une gamme de fréquences comprise entre 30 et 75 mhz. Parmi les milieux biologiques, nous avons choisi le sang du fait que l'on peut aisément modifier sa composition et ses propriétés physico-chimiques pour en vérifier l'impact sur la propagation de l'onde élastique. Dans le sang, l'absorption résulte de deux processus distincts: l'un macromoléculaire, l'autre corpusculaire. C’est à l'absorption corpusculaire que nous nous sommes intéressés plus particulièrement étant donné l'existence de modèles théoriques dans lesquels des corrélations sont établies avec des paramètres mécaniques du milieu. Nos résultats expérimentaux sont analysés qualitativement en fonction de la fréquence, de l'état de la membrane globulaire et de la concentration corpusculaire moyenne en hémoglobine. A partir du modèle théorique décrivant la propagation d'une onde élastique dans une suspension de particules visqueuses de faible dimension devant la longueur d'onde acoustique, nous déduisons de nos mesures de vitesse et d'atténuation, deux paramètres de caractérisation du globule rouge: la compressibilité adiabatique et le coefficient de dilatation thermique isobare. Ces deux paramètres conditionnent la déformabilité du globule rouge, caractéristique influant sur la circulation sanguine.
28
Toler, Tanikka. "Effects of Light Exposure on the Release of Oxygen from Hemoglobin in a Red Blood Cell Suspension". VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1637.
Testo completoAbstract (sommario):
The main function of the cardiovascular system is to deliver a sufficient quantity of oxygenated blood to the tissues, cells, and organs of the body in order to provide the cells with essential nutrients for metabolism and for the removal of waste products. All cells require and utilize oxygen. Oxygen is transported to various cells and tissues via red blood cells flowing through the microcirculation of an organism. Measurement of oxygen transport in the microcirculation has shown that about ten times more oxygen appears to leave the blood of arterioles than can be accounted for by diffusion. One possibility to explain the high oxygen loss is an increased release of oxygen due to exposure of blood to light. In the present in vitro study the release of oxygen from red blood cells was measured during exposure of the sample to light by monitoring the change in PO2 of the suspension during light exposure. A PO2 electrode was calibrated using PBS solution and utilized to monitor the change in current in the present study. Red blood cell suspensions were made using blood withdrawn from male Sprague-Dawley rats. The red blood cell suspension was placed in a closed sample chamber and exposed to light for 5 minutes. A method to correct for the drift of the PO2 electrode and temperature change during the experiment was implemented. The calculated change in PO2 of the RBC suspension due to light exposure was small. The change of PO2 in the sample chamber during light exposure was an average of 1.60 ± 0.9 mmHg (SEM). The contribution of photo-dissociation of oxygen from oxygenated hemoglobin molecules to the observed oxygen loss per RBC can account for only about 0.01% of the observed in vivo results. Therefore, light-associated oxygen release is negligible. These findings disprove the hypothesis of the present study, in which light exposure does not have a significant effect on oxygen release and thus rules out this possible explanation for the discrepancy between experiment and theory.
29
Terrasso, Ana Paula Barreto. "Development of novel human cellular models for neurotoxicity studies". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8488.
Testo completoAbstract (sommario):
Dissertation to obtain master degree in
Genética Molecular e BiomedicinaInformation currently available on neurotoxicity of chemicals is scarce and there are a growing number of new compounds to be tested. Therefore, new strategies are necessary to identify neurotoxic agents with speed, reliability and respect for animal welfare. The limited availability of primary human brain cells means that there is a need for human cell lines that reliably model human neurons and astrocytes. Despite the advances in stem cell research, numerous challenges must be overcome before this technology can be widespread used, such as low differentiation efficiency. Human pluripotent embryocarcinoma NTera2/cloneD1 (NT2) cell line is an alternative cell source from which neurons and astrocytes can be derived in vitro. The aim of this work was to develop scalable and reproducible novel human cellular models using NT2 cells as source of differentiated neural phenotypes. A 2D culture system for astrocytic differentiation was implemented. After 4 weeks of differentiation with retinoic acid followed by 5 weeks maturation with mitotic inhibitors, astrocytes obtained expressed vimentin, GFAP, S100- and GLT-1 as characterized by immunodetection and qRT-PCR. Then, a 3D culture approach was adopted, using stirred suspension culture systems, in which cell-cell and cell-extracellular matrix interactions occur, mimicking better the in vivo situation. NT2 cells, inoculated as single cells, spontaneously aggregated without compromising their pluripotency. Optimization of stirring rate allowed control of aggregate size along time. After 3 weeks of RA treatment and 2 weeks of maturation, neurons expressing βIII-tubulin, MAPs and synaptophysin and astrocytes expressing vimentin, GFAP, S100- and GLT-1 were detected, as characterized by immunodetection and qRT-PCR. Furthermore, astrocytes presented a 2.5-fold higher yield than that observed in 2D culture systems. Results showed that NT2 differentiated cells are promising models for neurotoxicity testing. Furthermore, the 3D culture systems developed herein can contribute to increase the relevance of these studies, recapitulating human neuron-astrocyte interactions in a 3D cellular context.
Fundação para a Ciência e Tecnologia - PTDC/EEB-BIO/112786/2009
30
Case, Natasha D. "Oscillatory Compressive Loading Effects On Mesenchymal Progenitor Cells Undergoing Chondrogenic Differentiation In Hydrogel Suspension". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6939.
Testo completoAbstract (sommario):
Articular cartilage functions to maintain joint mobility. The loss of healthy, functional articular cartilage due to osteoarthritis or injury can severely compromise quality of life. To address this issue, cartilage tissue engineering approaches are currently in development. Bone marrow-derived mesenchymal progenitor cells (MPCs) hold much promise as an alternative cell source for cartilage tissue engineering. While previous studies have established that MPCs from humans and multiple other species undergo in vitro chondrogenic differentiation, additional research is needed to define conditions that will enhance MPC differentiation, increase matrix production by differentiating cultures, and support development of functional tissue-engineered cartilage constructs. Mechanical loading may be an important factor regulating chondrogenic differentiation of MPCs and cartilage matrix formation by chondrogenic MPCs. This thesis work evaluated the influence of oscillatory unconfined compressive mechanical loading on in vitro MPC chondrogenic activity and biosynthesis within hydrogel suspension. Loading was conducted using MPCs cultured in media supplements supporting chondrogenic differentiation. Possible interactions between the number of days in chondrogenic media preceding loading initiation and the ability of the MPC culture to respond to mechanical stimulation were explored in two different loading studies. The first loading study investigated the effects of 3 hour periods of daily oscillatory mechanical stimulation on subsequent chondrogenic activity, where chondrogenic activity represented an assessment of cartilage matrix production by differentiating MPCs. This study found that oscillatory compression of MPCs initiated during the first seven days of culture did not enhance chondrogenic activity above the level supported by media supplements alone. The second loading study evaluated changes in biosynthesis during a single 20 hour period of oscillatory mechanical stimulation to assess mechanoresponsiveness of the MPC cultures. This study found that MPCs modulated proteoglycan and protein synthesis in a culture time-dependent and frequency-dependent manner upon application of oscillatory compression. Together the two loading studies provide an assessment of dynamic compressive mechanical loading influences on MPC cultures undergoing chondrogenic differentiation. The information gained through in vitro studies of differentiating MPC cultures will increase basic knowledge about progenitor cells and may also prove valuable in guiding the future development of cartilage tissue engineering approaches.
31
Mamdoh, Magdy Nashed Gaid Mariam [Verfasser], e Ludger [Akademischer Betreuer] Beerhues. "Benzoic acid metabolism in Sorbus aucuparia cell suspension cultures / Mariam Mamdoh Magdy Nashed Gaid ; Betreuer: Ludger Beerhues". Braunschweig : Technische Universität Braunschweig, 2010. http://d-nb.info/1175827193/34.
Testo completo
32
Trexler, Melody May. "A cyclical semi-continuous process for production of heterologous proteins in metabolically regulated plant cell suspension cultures /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
Testo completo
33
Gouws, Anton. "Optimum temperatures for colour development in apples". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5164.
Testo completoAbstract (sommario):
Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Peel colour is an important quality factor in the production of bi-coloured apple fruit. Most markets set minimum requirements for red colour coverage. Fruit that do not meet these requirements are downgraded and has a major impact on the profitability of apple production in South Africa. South African apple production areas are amongst the warmest in the world. Since anthocyanin accumulation requires induction at low temperature and synthesis require mild temperatures, experiments were conducted to investigate optimum day and night temperatures for red colour development throughout fruit development for red and bi-coloured apple cultivars grown in South Africa. We found that redder strains of bi-coloured apple cultivars did not appear to owe their enhanced pigmentation to higher temperature optima for anthocyanin synthesis. The optimum day temperatures for red colour development in the different cultivars seemed to differ between seasons, but not between production areas. In general, red colour in the cultivars evaluated developed maximally between 17 ºC and 25 ºC. The optimum day temperature for red colour development remained constant throughout fruit development for most cultivars, but increased roughly from 14 ºC to 22 ºC in ‘Cripps’ Pink’ between January and April. The extent of red colour development increased during fruit development in all the cultivars assessed. We were unable to determine optimum induction temperatures for red colour development. ‘Royal Gala’ from Ceres seemed to benefit from induction at 4 ºC while red colour in ‘Fuji’ decreased with decreasing temperature. To explain the presence of anthocyanins in immature apple fruit, we tested the hypothesis that anthocyanins protect the peel from photoinhibition and photooxidative damage during conditions of increased light stress. First we established that the rate of colour change in response to a passing cold front appears to be sufficient to provide photoprotection during a cold snap. Also in agreement with the hypothesis, ‘Cripps Pink’ peel incurred significantly more photoinhibition at low temperature (16 ºC) compared to mild (24 and 32 ºC) and high (40 ºC) temperature under high irradiance with visible light. Recovery rate was temperaturedependent, being the slowest at low temperature and increasing with temperature. The photoapparatus in ‘Cripps Pink’ peel appears to be particularly sensitive to light stress at low temperature throughout the season, with significant photoinhibition occurring even at moderate temperature (24 ºC). The sensitivity of the apple peel to photoinhibition increased throughout the season at lower irradiance levels, but remained the same at higher irradiance. In our final experiment, fruit were exposed to high irradiance at low and mild temperature before exposure to high temperature in combination with high irradiance. This was done to test the hypothesis that photoinhibition incurred during cold snaps predisposes peel to photothermal damage when temperature increases again after the cold snap. Unfortunately, due to the severity of the stress incurred in response to high temperature treatment, the results were inconclusive.
AFRIKAANSE OPSOMMING: Vrugkleur is ‘n belangrike kwaliteitsfaktor in die produksie van tweekleurappels. Die meeste markte stel minimum vereistes vir rooi kleurbedekking. Vrugte wat nie aan hierdie vereistes voldoen nie, word afgegradeer. Suid-Afrika se appel produksie areas word beskou as van die warmste ter wêreld. Antosianien akkumulasie benodig induksie by lae temperature gevolg deur sintese in lig by matige temperature. Gevolglik het swak rooi kleurontwikkeling onder plaaslike toestande ‘n groot impak op die winsgewendheid van appelproduksie in Suid-Afrika. Eksperimente is uitgevoer om die optimum dag- en nagtemperature vir rooi kleurontwikkeling tydens vrugontwikkeling vir die rooi en tweekleur appel kultivars wat in Suid-Afrika geproduseer word te bepaal. Ons het gevind dat die verhoogde pigmentasie van rooier seleksies van tweekleurappel kultivars nie aan ‘n hoër temperatuur optimum vir antosianiensintese toegeskryf kan word nie. Die optimum dag temperature vir rooi kleurontwikkeling vir die onderskeie kultivars verskil klaarblyklik tussen seisoene, maar nie tussen produksie areas nie. Oor die algemeen het kleurontwikkeling maksimaal plaasgevind tussen 17 ºC en 25 ºC. Die optimum dagtemperatuur vir rooi kleurontwikkeling het konstant gebly tydens vrugontwikkeling, buiten vir ‘Cripps’ Pink’ waar dit toegeneem het van ongeveer 14 ºC tot 22 ºC vanaf Januarie tot April. Die mate van rooi kleurontwikkeling het in al die kultivars toegeneem deur die loop van vrugontwikkeling . Ons kon nie daarin slaag om optimum induksie temperature vir rooi kleurontwikkeling vas te stel nie. Rooi kleurontwikkeling van ‘Royal Gala’ uit Ceres is moontlik bevorder deur induksie by 4 ºC, terwyl ‘Fuji’ se rooi kleur afgeneem het met ‘n verlaging in induksie temperatuur. Ten einde die teenwoordigheid van antosianien in onvolwasse appelvruggies te verduidelik, het ons die hipotese getoets dat antosianien die vrugskil beskerm teen fotoinhibisie en fotooksidatiewe beskadiging gedurende tydperke van verhoogde ligstres. Eerstens het ons bevestig dat die tempo van kleurontwikkeling in reaksie op ‘n koue front waarskynlik vinnig genoeg is om fotobeskerming te verleen. Vervolgens is gevind dat ‘Cripps’ Pink’ vrugskil aansienlik meer fotoinhibisie ervaar het by lae temperatuur (16 ºC) in vergelyking met matige (24 ºC en 32 ºC) en hoë (40 ºC) temperatuur onder hoë irradiasie met sigbare lig. Die hersteltempo was temperatuur-afhanklik; dit was die stadigste by lae temperatuur en het toegeneem met ‘n toename in temperatuur. Die foto-apparaat in ‘Cripps’ Pink’ vrugskil blyk besonder sensitief te wees vir ligstres by lae temperatuur regdeur die groeiseisoen met aansienlike fotoinhibisie by selfs matige temperatuur (24 ºC). Die sensitiwiteit van die vrugskil vir fotoinhibisie het toegeneem deur die groeiseisoen by laer ligvlakke, maar het dieselfde gebly by hoër vlakke van irradiasie. Laastens is vrugte blootgestel aan hoë irradiasie by lae en matige temperatuur voordat dit vervolgens blootgestel is aan hoë temperatuur in kombinasie met hoë irradiasie. Dit was om die hipotese te toets dat fotoinhibisie wat opgedoen word gedurende ‘n onverwagte koue periode, die skil meer vatbaar maak vir fototermiese skade sodra die temperatuur weer styg na die koue periode verby is. Ongelukkig het die hoë temperatuur stres al die behandelings tot so ‘n mate geaffekteer dat dit onmoontlik was om enige gevolgtrekkings vanuit ons resultate te maak.
34
Velez, Suberbie L. "Characterisation of the bioreactor environment and its effect on mammalian cell performance in suspension culture during antibody production". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1410199/.
Testo completoAbstract (sommario):
The production of therapeutic proteins with complex post-translational modifications is typically performed with suspension adapted mammalian cells, in stirred tank bioreactors (STRs). In this environment cells are exposed to hydrodynamic forces derived from both agitation and aeration. An improved understanding of these forces and the resulting cellular response is therefore critical. This thesis has characterised the hydrodynamic conditions within a STR using computational fluid dynamics and investigated the lethal and sub-lethal effects of this environment on CHO cells during the production of a monoclonal antibody. The hydrodynamic forces varied within the vessel, with the maximum forces being present in the impeller region. Energy of dissipation rates obtained from single and multiphase models were found to be higher than those previously reported. Having gained understanding of the hydrodynamic forces within the bioreactor, the environment was changed in a systematic manner. To create a bubble and bubble free environment within the STR direct gas sparged and silicone membrane aerated systems (SMAS) were used. When cells were subjected to the stress of gas-liquid interfaces they entered apoptosis at an earlier stage of cell culture, had decreased F-actin intensity and a modified cell morphology. This had implications on cell strength and impurity release during primary recovery. The application of fed-batch mode and mild hypothermic conditions were shown to be beneficial; delaying the onset of lethal and sub-lethal effects, enabling higher cell densities to be obtained, prolonging the culture duration and increasing product titre. The vital role of shear protectant agents at gas-liquid interfaces was highlighted; in absence of Pluronic F-68 cell death occurred within 24 hours of inoculation, but growth proceeded when using the SMAS. The glycosylation profile was not significantly affected by the STR environment, with harvest point being shown to have a greater impact on the relative abundance of different glycoforms.
35
Lai, Ying-Hui, e 賴穎慧. "Production of the mGMCSF in rice cell suspension culture". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19499568135528010150.
Testo completoAbstract (sommario):
碩士國立中央大學
生命科學研究所
97
After the production of insulin by E. coli in 1970s, more and more therapeutical proteins were produced by different organisms, such as microorganism, insect and mammal. In the past few years, the plant expression system had been used to produce many kinds of recombinant proteins because of low cost, safety and post-translational modification. The rice cell production system is one of the most efficient plant expression systems. To improve the yield of the rice cell expression system, different signal peptides including αAmy3, CIN1 and 33kD have fused to the N-terminal of GFP or mGMCSF to explore the secretory efficiency of foreign proteins. Transgenic rice containing fusion proteins have been generated, and the intracellular and extracellular recombinant proteins were determined by western blotting to compare the secretory efficiency of three different signal peptides.. We found that CIN1 is the most efficient signal peptide for the secretion of both GFP and mGMCSF. On the other hand, we found that the addition of A1 intron in the 5’ end of fusion protein give rise to better secretory efficiency than the Ubi intron in the rice cell expression system. In the further, we would like to combine the most efficient signal peptide, the strong promoter and the inhibition of proteolysis to develop highly protein expression system in rice cells.
36
Cheng, Yuan-Shun, e 振芫舜. "Fuel Cell Hybrid Scooter Suspension Design and Vibration Analysis". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/34236347903018266342.
Testo completoAbstract (sommario):
碩士國立臺灣大學
機械工程學研究所
97
Fuel cell system is an important part to extend mileage and reduce recharging time for electrical vehicle. However, there are some limits under operation; the vibration tolerance is much lower than internal combustion engine. Although fuel cell stack operates with few moving parts and almost no vibration, and the vibration from road could still cause damage to the fuel cell stack. In this study, a combination of fuel cell hybrid scooter vibrating simulation analysis and suspension system adjustments were proposed to reduce the road impact acceleration on fuel cell stack. According to the fuel cell stack sustainable vibration range, a CAE software ADAMS is added to do sensitivity analysis and suspension system design to reduce the vibrating acceleration. In the analysis result, the vibrating acceleration and dynamic performance for the scooter could be successfully simulated under different riding speed, and successfully be reduced by using spring – damping system. The experiments verified CAE simulating results and show a high coherence, also successful reducing the vibrating acceleration under 3g. By using the design method proposed in this research, a fuel cell scooter could also keep the dynamic performance and achieve fuel cell stack protection target without changing conventional riding custom.
37
Lin, Jin-Lan, e 林錦蘭. "Cell suspension culture of panax ginseng C. A. meyer". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/21117958435956403079.
Testo completoAbstract (sommario):
碩士國立臺灣大學
園藝學研究所
84
Embryogenic cell suspension culture was established from long -time cultured root drieved embryogenic callus. Embryogenic callus cultured in modified MS liquid medium with 5% coconut milk and 0.5 g/l casein hydrolysate produced shoots.The shooting callus transfered to B5 solid medium which is contained 1 ppm GA and 1 ppm BA produced green plants with normal shoots and roots. Transfer the callus to MS solid medium contained 1 ppm 2,4-D will induce somatic embryo formation.MS liquid medium with more than 3ppm 2,4-D depressed the embryogenic cluster formation. Coconut milk or 1 ppm kinetin did not depress the growth of the embyogenic clusters. Low concentration of PPT (0.1 to 0.5 ppm ) in MS liquid medium had promotive effect in embryogenic clusters formation. PPT at high concetration (more than 1 ppm) retarded growth of callus. B5 liquid medium contain 1 ppm GA and 1 ppm BA induced embryoid germination. The small embryogenic clusters cultured in 4℃ 2 days have less vitality , easier brown than the clusters never cultured in 4℃.Embryogenesis formation shoot or root , and the time needed for these develop process in plating clusters is related with the clusters size and maturation degress of the embryoids and the composition of the solid medium.
38
Nims, Nathan Ezekiel. "The regulation of Taxol production in Taxus suspension cell culture". 2008. https://scholarworks.umass.edu/dissertations/AAI3336965.
Testo completoAbstract (sommario):
Plant-derived specialized metabolites are used as pharmaceuticals, dyes and fragrances. Due to the complex nature of these compounds, the continued dependence on plants to synthesize these products has persisted. Many of these products are found at low abundance in plants, so increasing the production of these compounds through metabolic engineering is desirable. An example of a plant-derived pharmaceutical found at low abundance is taxol (Taxol® - Bristol-Myers Squib). Taxol is an anti-cancer agent that is in high demand. Plants in the genus Taxus produce Taxol. Taxus cell suspension cultures are currently being used to meet the demands, however, taxol accumulation is limited. The low yield found in Taxus cultures has prompted biologists and engineers to attempt increasing production of this valuable metabolite. In order to increase taxol accumulation, a better understanding of the metabolic pathway is required. There are unknown steps in the biosynthetic pathway, so cloning the genes involved with these steps is needed. Also, information regarding factors that regulate of the biosynthetic pathway must be collected. In this dissertation, novel genes are identified and the expression profiles of the known genes after methyl jasmonate (MJ) elicitation are revealed. The expression profiles of these genes are directly correlated with the taxol precursor accumulation. Transcription of these pathway genes occurs with MJ elicitation, demonstrating that the response to MJ elicitation is at the level of transcription; thus, taxol production is correlated with taxol pathway gene transcription. A transcription factor has been cloned from Taxus and characterized. This transcription factor is similar to regulators of the MJ-inducible responses in other plants. This Taxus transcription factor, TcJAMYC, activates transcription of taxol pathway gene and also binds to DNA elements found in the promoters of these pathway genes. This transcription factor has the potential to increase taxol accumulation in transgenic Taxus cultures.
39
Chin, Chou Yun, e 周昀瑾. "Establishment of a rice tPA-transgenic cell suspension culture system". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/37555902184986500299.
Testo completoAbstract (sommario):
碩士輔仁大學
生物學系
89
tPA( tissue-type plasminogen activator) protein, known to be able to activate and convert plasminogen into plasmin in blood and functionally dissolve blood clots, has been succefully used to treat heal acute ischemic stroke and myocardial infraction clinically. Commercially available tPA is commonly recombinant tPA lacking glycosylation. Completely glycosylation will , however, enhance tPA’s bioactivity up to 40-50% according to the research by Sinniger et al. This research work has been aimed to use transgenic plant which has a glycosylation machinery comparable to mammal as an express system to produce tPA with higher bioactivity. Plant expression vector which carry tpa gene was introduced into suspension cultured rice cells by twin-pulsed mode with electroporation. Furthermmore, mammalion-originated gene encoding GRP (glucose-regulating protein) was engineered into the suspension cultured rice cells in attempt to help to ensure the proper conformation of tPA in the transgenic plant cells.The PCR and Western analysis confirmed that the transgenic rice suspension cultured cells could stably express GRP protein. Western blotting data showed that different gene expression cassettes produced different level of tPA expression.
40
何佳靜. "studies on callus and suspension cell culture of Ginkgo biloba". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/52722092894223431275.
Testo completoAbstract (sommario):
碩士國立東華大學
生物技術研究所
87
Ginkgo (Ginkgo biloba), a species of ginkgoaceae, was first recorded in Zea-Ung-Pen-Ts''ao-Ching. Its fruit, one of the Chinese medicinal herbs, was used mainly for treating cough. The purpose of this study was to establish the suspension culture of Ginkgo biloba for producing its secondary metabolites, such as ginkgolide B (GKB) and quercetin. Cell suspension culture was established from the leaves- derived callus. The culture conditions for both cell growth and secondary metabolites production were then evaluated. It was found that MS basal medium with the addition of 4 mg/l NAA, 0.5 mg/l kinetin and 3% sucrose was sufficient for the initial establishment of callus from leaves. The callus could be maintained for many generations in WPM basal medium with the addition of 3% sucrose, 4 mg/l NAA, 0.5 mg/l kinetin and 0.4% gelrite. Based on the experimental results, the optimal condition of cultivating Ginkgo biloba callus in suspension state, includes a WPM medium with the addition of 3% maltose or sucrose, 4 mg/l NAA, 0.5 mg/l kinetin, a pH of 5.2, an inoculum amount of 3 ml packed cell volume for a 25 ml culture and a shaking speed of 140 rpm. The cell growth rate showed no difference between the cells cultivated in dark or light conditions. The production of ginkgolide B from callus or suspension cells was found not growth-associated, and rapidly increased in the late log phase. The amounts of ginkgolide B of callus and of suspension cells could reach 65.16 mg/gDCW and 61.91 mg/gDCW, respectively. However, little quercetin was obtained in the callus and suspension cells growing under the conditions tested, and the production of quercetin was decreased with culture time.
41
QUE, FU-XIN, e 闕甫伈. "tudies on the cell suspension culture of angelica sinensis (Oliv.)Diel". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/55731045186869173620.
Testo completo
42
Liu, Chi-Han, e 劉季函. "Suspension cell culture and berberine production of Phellodendron wislonii Hayata＆Kanehira". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/69274716429124656030.
Testo completoAbstract (sommario):
碩士中臺科技大學
藥物科技研究所
99
Berberine is an important medicine used for stomach and intestinal illness. Whang-Po( Phellodendro wislonii Hayata et Kanehira ), a deciduous tree of Rutaceae, was first recorded in Shen- Nung-Pen-Ts,ao- Ching under the inferior category and it was listed in Pen-Ts,ao- Gang–Mu as superior medicine the middle woody category. Whang-Po is used for curing fevers, inflammation, etc. Taiwan Whang-Po( P. wilsonii Hayata et Kanehira) , a native plant in Taiwan, is an excellent source of Whang-Po material because of high berberine content. Taiwan Whang-Po must be grown for more than 6-8 years for harvesting bark. In addtion it has been excessively picked in the primary habitat. Establishment of Taiwan Whang-Po suspension cell system may be an alternative choice for berberine production. Two months old plantlet was used as explant to induce callus in this study. Medium, pH, and growth regulator were evaluated to establish the cell suspension culture system. Content of berberine is an important indicator. Leaf petiole was proved to be the best explant for callus induction. The addition of 0.5 mg/l 2,4-dichloro- phenoxyacetic acid (2,4-D) and 1.0 mg/l 6-benzylaminopurine(BA) to the Murashige and Skoog (MS) basal medium was effective in inducing callus formation.When callus was transferred from MS to woody plant medium (WPM ), callus growth and proliferation was stimulated. The most suitable medium composition for subculture of callus was WPM basal salts supplemented with 0.5 mg/l 2,4-D, 1.0 mg/l BA, 10 ％ coconut milk, 3 ％ sucrose and 1％ agar, with a pH value of 5.2. The interval of subcultures was between 14 to 16 days. Cell suspension cultured on a medium containing WPM basal salt with 0.5mg/l of 2,4-D and shook at 100 rpm showed vigorous and well-grown suspension cells. Cell growth amounts after 20 days culture was 9 folds as those of the initial inoculum. But no berberine was produced in callus and such suspension cell via 75% ethanol extraction and high performance liquid chromatography (HPLC) analysis.However, the addition of whem 2 mg/l BA and 6 mg/l α-naphthaleneacetic acid(NAA) in the medium at 18th day of suspension cell culture induced berberine biosynthesis. Berberine content in suspension cell at 28th day was 188.68 μg/g dry weight. Keyword：Phellodendron amurense Rupr. var. wilsonii ( Hayata et Kanehira), callus, suspension cell, berberine, HPLC
43
Liu, Chung-Min, e 劉重民. "Studies on Callus nad Cell Suspension Culture of Bupleurum marginatum Willd". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/24614137613480253510.
Testo completo
44
Han, Shih-Cheng, e 韓士晟. "Studies on the cell suspension culture ofSaussurea involucrata Karelin et Kirilov". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/22xv5t.
Testo completoAbstract (sommario):
碩士國立中興大學
農藝學系所
106
Saussurea involucrate is one of the most important medicinal plants in China. It has used in the Chinese system of traditional medicine for the treatment of many disease such as arthritis, hypertension, cancer, gynecological diseases, etc. Owing to over-exploitation of the wild plants for commercial purposes, ecological destruction of the natural habits, and the difficulty of cultivation. The species has become endangered. Therefore, we need a more efficient way to propagate this plant. Plant tissue culture is a technique for rapid multiplication of the whole plant, or use plant cell culture to induce specific bioactive compound. This study is going to establish cell suspension culture system of S. involucrate. Compared different auxin that influenced suspension cell induction and proliferation. Selected the high-yield cell line, then compared culture environment and medium composition that influence the propagation of suspension cell. On the other hand, this study analyzed the effect of different cell size, 2,4-dichlorophenoxyacetic acid (2,4-D) concentration and ventilation period on suspension cell that inoculated on solid medium. Secondary metabolite analysis focused on chlorogenic acid and rutin. Try to find the best culture condition that can proliferate suspension cell of S. involucrate and produce secondary metabolite efficiently. The result showed that the suspension cell of S. involucrate was induced on 1/2X strength of Murashige and Skoog’s (MS) medium supplemented with 0.5 mg/L 6-benzylaminopurine (BA) and 0.5 mg/L 2,4-D, and proliferated on 1/2X MS supplemented with 0.5 mg/L BA and 0.5 mg/L α-nhthaleneacetic acid (NAA). Suspension cell of S. involucrate incubated at lower shaking speed (80 rpm), lower inoculum volume (0.5-1 ml PCV/20 ml medium), lower temperature, higher sucrose concentration (4.5%) or under light had a higher proliferation rate. The HPLC analysis showed that the highest chlorogenic acid content in suspension cell was incubated under dark at 14th day (2.41 mg/g dw), and the highest rutin content in suspension cell was incubated under light at 35th day (1.29 mg/g dw). The highest chlorogenic acid content (3.54 mg/g dw) in callus that incubated on solid medium supplemented with 0.1 mg/L 2,4-D, the flask was closed with three layers of dispense papers and had an additional layer of parafilm which was removed after 10 days, totally cultured for 30 day. The highest rutin content (1.85 mg/g dw) in callus that incubated on solid medium supplemented with 0.1 mg/L 2,4-D, and the flask was closed with three layers of dispense papers, totally culture for 30 days.
45
吳國隆. "Production of L-DOPA via cell suspension cultures of Stizolobium hassjoo". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/43575671641576336047.
Testo completo
46
Liu, Shi-Hua, e 劉士華. "Studies on cell suspension culture and somatic embryogenesisi of Musa formosana". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/44187355552827515211.
Testo completoAbstract (sommario):
碩士國立臺灣大學
園藝學研究所
97
Summary The young male inflorescence of Taiwan native diploid banana (Musa formosana) was used as explant, and cultured in modified MS medium supplemented with complex auxin including IAA 1 mg/L, NAA 1 mg/L, and 2,4-D 1 mg/L and Picloram 3 mg/L suitable for callus formation. The top male hand portions ranged from the 13th to 17th sections were capable to give rise 64-82% callus formation on the medium as above. The zygote embryos were aptly to generate embryogenic callus on MS medium added with NAA 1 mg/L, IAA 1 mg/L combined Picloram 1 mg/L or Dicamba 1 mg/L in 2-3 months after inoculation. In further, the callus proliferation could be subcultured on the above medium but supplemented Picloram or Dicamba as the sole auxin. The male inflorescence-derived callus was subcultured in liquid TB5 medium ( Ma, 1988), and obtained homogenous cell population about 2 month after suspension culture. The extracellular pH level in TB5 medium of the cell suspension culture was varied in the range pH 4.45±0.37, and also concordantly associated with growth phase change. The addition of MES 10 g/L could upgrade the extracellular pH in the stable level 4.51±0.17, and also induce the preembryogenic cells destine to polar growth depicted by the asymmetric division. Controlling extracellular pH at 5.7 and culture in SH3、SH3 with MES led up to the polar growth. The cells culture in SH3 with MES were polarized earlier, and remain extracellular pH over 5.46. After polarization treatment for 7 days, the embryogenic cells could formed proembryo and globoids. Used PIPES with SH3 medium could also be induced to polarization and formed globoids with complete protoderm Acidic treatment (pH 4.0-4.5) promoted globoids to disunite small mass and release single cells. After acidic treatment for 7 and 14 days, the bicellular trended to do symmetric division. Controlling extracellular pH at 5.7 and culture in SH3、SH3 with MES led up to the polar growth. The cells culture in SH3 with MES were polarized earlier, and kept extracellular pH over 5.0. After polarization treatment for 7 days, the embryogenic cells could formed proembryo and globoids. Used PIPES with SH3 medium could also be induced to polarization and formed globoids with complete protoderm Before plating, the suspension prembryogenic cells were pretreated on TB5, SH3 medium with or without was consistent 10 g/L MES. The SH3 pretreated cells regenerated higher quantity of somatic embryos on plating medium than those on TB5, TB5+MES and SH3+MES pretreated. The size of suspension cell cluster was separated with <60 or 30-60 meshes and were diluted 1/30 c.c PCV proceeding to plat on 8ml SH3 medium with filter paper and cotton as the culture bridge, could development normal somatic embryos than agar, gelrite and 4 ml SH3 addition. Somatic embryo inoculated on 1/2 MS medium supplement with 10 mg/L BA induced 69% of shooting. The rooting rate did not increase, when medium supplement NAA. However, the shooting rate increase of plantlets on medium complex added NAA with BA. The increase of shooting rate and leave length in medium GA, but the leaves had exceptional discoloration and elongation.
47
Liao, Hui-fan, e 廖慧帆. "Application of light weight PLGA microcarrier to adhesive cell suspension culture". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/56041819437618535983.
Testo completoAbstract (sommario):
碩士大同大學
生物工程學系(所)
96
Glycosylation and post-translational modification of recombinant proteins are the unique feature of mammalian cell system. However, the productivity of recombinant protein by mammalian cells is much lower than that of microorganisms. Chinese hamster ovary cell line is the most popular mammalian host for the commercial production of therapeutic proteins. We used Chinese hamster ovary cells (5/9 M alpha 3-18, BCRC 60185, CHO cells) to express macrophage colony-stimulating factor (M-CSF), which can stimulate macrophage proliferaction, differenciation and survival. Cells were inoculated into culture system containing light weight porous microspheres, which were made of biodegradable polymer, PLGA. The support of PLGA microspheres reduced cell damage resulting from the shear force. The particle size of dense PLGA particles was 117.8±15.0 μm；1% NH4HCO3-PLGA microcarrier was about 375.8±78.5 μm；5 % NH4HCO3-PLGA particle size was 442.4±25.8μm。The pore size of 1 % NH4HCO3-PLGA and 5 % NH4HCO3-PLGA was between 17~18μm。 Cytodex 3 is a commercial cell culture microcarrier, which was cross-linked dextran coated with denatured collagen. After cell culture with Cytodex 3 for 4 days, the cell density reached maximum, and the onset of cell death was observed. The cell culture with PLGA microcarriers, made of 1% NH4HCO3 and PLGA, the cells grew till day 13. The final density of cells was similar to that cultured with Cytodex 3. The 5 % NH4HCO3-PLGA microcarriers showed the massive cell death up to day 17, but the cell growth rate and cell density were both smaller to that with 1% PLGA microcarriers. The yield of M-CSF is higher for cell culture with 1 % NH4HCO3-PLGA microcarrier. The 1% NH4HCO3-PLGA microcarrier was the best in cell density and M-CSF production.
48
Chang, Jia-Ci, e 張珈錡. "Study on callus induction, plant regeneration and cell suspension culture of nilegrass". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77304893213474193241.
Testo completoAbstract (sommario):
碩士國立嘉義大學
農藝學系研究所
98
The objectives of this study were to establish an efficient culture system for callus induction, plant regeneration and cell suspension from immature inflorescence of nilegrass (Acroceras macrum Stapf cv. Taishu No.1). Different types and concentration of plant growth regulators were tested in order to obtain the best callus and cell suspension culture conditions for plant regeneration. Explants were cultured on MS medium supplemented with 2.0 mgL-1 2,4-D and different concentration of BA, 2-ip and CPPU for callus induction. The percentage of callus induction with 2.0 mg L-1 2,4-D and 0.5 mg L-1 BA was 42.3% and then callus were transferred to MS medium with different concentration of TDZ for shoot regeneration. The percentage of shoot regeneration from callus induced with 0.5 mg L-1 BA was increased to 90.0% with 0.05 mg L-1 TDZ that was much higher than the callus induced with 2.0 mg L-1 2,4-D without BA. It means BA influenced the callus induction and plant regeneration. The callus induction frequency was 43.5% with 2.0 mg L-1 2,4-D and 1.0 mg L-1 2-ip and the shoot regeneration frequency was only 50.0 % with 0.05 m L-1 TDZ. The frequency of callus induction was 72.4% with 2.0 mg L-1 2,4-D and 0.10 mg L-1 CPPU, but the frequency of shoot regeneration was decreased to 16.7% with 0.05 mg L-1 TDZ. It could be enhanced to 75.0% for shoot regeneration by added 0.50 mg L-1 NAA and 0.50 mg L-1 TDZ. It was indicated callus inducted from different cytokinins need optimum medium for regeneration. The frequency of transparent and friable callus were 58.8% with 2.0 mg L-1 2,4-D. Adding different cytokinins (BA, 2-ip, Kinetin and TDZ) with 2.0 mg L-1 2,4-D were increased the frequency of white and compact callus that were benefice for shoot regeneration. It was significant increased the shoot regeneration frequency with 0.5 mg L-1 NAA and 0.5 mg L-1 TDZ compared to 0.05 mgL-1 TDZ. The callus induced with 2.0 mgL-1 2,4-D and 0.5 mg L-1 BA was initiated for cell suspension. Stable cell suspension culture was established in MS medium supplemented with 1.0 mg L-1 2,4-D and 50 mg L-1 casein hydrolysate. The frequency of cell subculture was every 14 day for 3 months. When cell clump were proliferated, change the medium with 2.0 mg L-1 2,4-D and 0.5 mg L-1 BA for induced white and compact callus that is useful for shoot regeneration. For increased the frequency of shoot regeneration from cell suspension culture, the proliferated cells were cultured with 1.0 mg L-1 BA for 4 weeks and then transferred to MS medium with 0.5 mg L-1 NAA and 0.05 mg L-1 TDZ. The frequency of shoot regeneration was reached 75.0% and the plantlet growth normally in field. The studies were successfully established a culture system for callus induction, plant regeneration and cell suspension culture of nilegrass. It will be useful for commercial production and improvement variety by biotechnology in future.
49
Chi-Ming, Yu, e 余齊明. "Prediction of Operational Strategy for Plant Cell Suspension Culture by Neural Network". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/01383783623790850133.
Testo completoAbstract (sommario):
碩士國立臺灣大學
化學工程學研究所
87
Artificial Neural networks were employed to simulate the cell growth and secondary metabolite production of plant cell culture system. Using experimental data of plant suspension cell culture, the optimal operation condition and the parameters for scaling up the bioreactor were investigated. Feed forward back propagation artificial networks was adopted for network structure. One or two hidden layers which were connected with the complexity of the input data was tried. Sigmoid type transfer function was implemented to the hidden layer while pure linear transfer function was used in output layer. Training a network was carried out with Levenberg-Marquardt method which exhibited a rapid and accurate performances. To train the network, adjustment of the numbers of artificial neurons in the hidden layer was necessary, thus avoiding the overfitting and underfitting .With inoculum density, rotational speed of agitator, cultivation period as input values and dry cell weight and L-DOPA content as output values, performance of proposed neural network was justified. Prediction of dry cell weight was satisfactory because of its simple physiological reaction. While the prediction of L-DOPA production was difficult due to its physiological complexity. Eddy length scale was employed to simulate the cultivation system. The result was not as good as predicted. It may be attributed to the shear stress characteristics of an agitated bioreactor. Extrapolation went successfully as the learning was abundant and covered almost all the characteristic data. Mixing time of bioreactor with different impellers were determined by neutralization of acid and alkali in a reactor. Gate turbine impeller exhibited the best mixing performance. The disk turbine showed longer mixing time, and the flat-blade turbine exhibited longest mixing time. There were no distinct dead zones for three impellers. The effect of liquid viscosity on mixing time was remarkable. This must be an important index for designing and scaling-up a bioreactor.
50
Hung, Shu-Ching, e 洪淑靖. "Study on Callus Induction and Cell Suspension Culture of Camptotheca acuminata Decne". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04237362168110985785.
Testo completoAbstract (sommario):
碩士南台科技大學
生物科技系
94
Camptotheca acuminata dence. is one of the unique perennial tree, fruit resembling the lotus. It grows in mainland China Yangtze valley and south various provincial capital areas. Camptothecin, one of its major metabolite, has the ability to control the leukemia. It has been confirmed that camptothecin has obvious effect on intestines cancer treatment. Depending on the geography factor and the weather effect, the content of camptothecin in tree is unstable, therefore the objective of the present investigation is to establish an Camptotheca acuminata dance. callus. Callus induction was obtained by culturing leaves and stem segments on MS basal medium supplemented with 1 mgL-1 BA and 3 mgL-1 2,4-D for 3 weeks. The callus were maintained and proliferated on MS basal medium supplemented with 1 mgL-1 BA, 1 mgL-1 NAA. Suspension cells were cultured on MS basal liquid medium supplemented with 1 mgL-1 BA, 1 mgL-1 NAA on a rotation shaker in the light condition. After 4 weeks culture, the dry weight of cells was about 3.95 g/L and CPT content achieved about 0.06(dry weight %).