To see the other types of publications on this topic, follow the link: Plant cells and tissues.

Dissertations / Theses on the topic 'Plant cells and tissues'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Plant cells and tissues.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Yang, Kung Chi. "The aging process of sapwood ray parenchyma cells in four woody species." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/31096.

Full text
Abstract:
Aging of ray parenchyma cells from the young sap-wood to recently formed heartwood was studied in single stems of Pinus banksiana Lamb., Picea mariana (Mill.) B.S.P., Abies balsamea (L.) Mill, and Populus tremuloides Michx. Season, radial location of cell within sapwood, and cell location vertically within a ray at a given radius were considered as factors which might influence the aging process. A 12 mm increment core was extracted at breast height, from the north aspect of a tree of each species in May and July for moisture content determination. Another set of cores from the south aspect of the same trees was collected in May, June, July, August, October, and November or December. These cores were used to investigate the physiological and cytological properties of living sapwood ray parenchyma cells. Qualitative and quantitative observations were made of the status of ray cells both with light and transmission electron microscopy in order to draw inferences concerning the sapwood/heartwood transformation from the aging of sapwood ray parenchyma cells. The sapwood moisture content of the three conifers studied was higher than that of heartwood, whereas in Populus tremuloides it was lower than that of heartwood. The sapwood moisture content in May was consistently greater than in July. Vitality of the sapwood ray parenchyma cells expressed by a new nuclear elongation index decreased from the outer sapwood towards the heartwood. The survival rate of the cells decreased curvilinearly from the middle sapwood towards the heartwood. At a given sapwood increment, a greater percentage of dead ray parenchyma cells was found among the marginal cells than among the central cells of a ray. No statistically significant difference was found between the vitality of the marginal and central cells, nor between any two contiguous sampling periods with exceptions in Pinus banksiana and Picea mariana between two contiguous sampling periods from July to December. No typical pattern for the distribution of lipid content was found. The pattern of starch distribution displayed significant species, radial, vertical and seasonal variation and showed two general patterns across the sapwood. Pattern A described a decreasing trend from the outer sapwood towards the inner sapwood. Pattern B was characterized by a relatively low starch content both in the outer as well as the inner sapwood. The starch content in Populus tremuloides and the lipid content in Pinus banksiana and Picea mariana displayed no statistically significant difference between marginal and central ray cells. The majority of ray parenchyma cells showed a statistically significant difference between two contiguous sampling periods in starch and lipid contents. There was no inverse relationship between the starch and lipid content over the growing season studied. Young ray parenchyma cells were rich in chromatin and cytoplasm which contained numerous cell organelles. These cells were characterized by amyloplasts which possessed one or more elongated starch granules with thylakoids and osmiophilic globuli, numerous small lipid droplets and mostly rod-like mitochondria. In contrast, aged ray parenchyma cells featured an aggregated, dense nucleus and cytoplasm which contained few cell organelles. These aged cells possessed enlarged swollen starch granules, large lipid droplets or lumps with two staining densities, round shaped mitochondria with inconspicuous cristae and a rough/broken plasmalemma. Some heartwood substances originated from the lipid lumps which appeared frequently in dying ray cells. Based on microscopic observations and measurements of the loss of vitality of ray parenchyma cells, a declining survival rate, the disintegration of cell organelles and the origin of heartwood substances from lipid lumps, it can be concluded that heartwood formation is largely associated with the death of sapwood ray parenchyma cells. The death of these cells is due to the passage of time.
Forestry, Faculty of
Graduate
APA, Harvard, Vancouver, ISO, and other styles
2

Cowan, Ashton Keith. "The metabolism of abscisic acid in higher plant tissues." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1002024.

Full text
Abstract:
The biosynthesis of ABA from R-[2-¹⁴C]-MVA was demonstrated in Persea americana cv. Fuerte mesocarp and in mature seeds of Hordeum vulgare cv. Dyan and cv. Himalaya. Radioactivity from R-[2-¹⁴-C]-MVA was also incorporated into the 1',4'-trans ABA diol in Persea americana mesocarp and a possible role for this metabolite as a precursor of ABA in plants is discussed. The biosynthesis of ABA from MVA could not be demonstrated in either turgid and waterstressed Hordeum vulgare cv. Dyan, Pisum sativum cv. Black-eyed Susan and Phaseolus vulgaris cv. Top-crop or in immature seeds of Pisum sativum and Phaseolus vulgaris. (R,S,)-[2-¹⁴C]-ABA was catabolised to PA, DPA and aqueous conjugates in leaves and mature seeds of Hordeum vulgare cv. Dyan, seedlings and immature seeds of Pisum sativum and Phaseolus vulgaris and in mesocarp from ripening fruits of Persea americana. PA and DPA were identified by either microchemical methods and/or capillary GC-MS. 7'-Hydroxy ABA was characterised as a novel ABA catabolite in light-grown and etiolated leaves of Hordeum vulgare by capillary GC-MS. Circular dichroism analysis revealed that it was derived predominantly from the (R)-enantiomer of ABA. This catabolite was absent in similar studies using the dicotyledons Pisum sativum and Phaseolus vulgaris. Refeeding studies with [¹⁴C]-PA, [C]-DPA and [¹⁴C]-7'-hydroxy ABA were used to confirm the metabolic interrelationship between ABA and its catabolites in both vegetative and non-vegetative tissues from monocotyledonous and dicotyledonous species. The methyl ester of (R,S,)-ABA was hydrolysed efficiently by light-grown leaves of Hordeum vulgare. Older, vegetative tissues catabolised (R,S,)-ABA more efficiently than their younger counterparts. In contrast, small, immature seeds of Pisum sativum catabolised (R,S,)-ABA more effectively than larger, immature seeds of this species. Light did not appear to influence ABA biosynthesis but markedly enhanced ABA catabolism. Light stimulated the overall rate of ABA catabolism in both vegetative and non-vegetative tissue. Water stress reduced ABA catabolism in Hordeum vulgare leaves but had little effect on this process in Phaseolus vulgaris seedlings. Pretreatment of tissues with (R,S,)-ABA retarded the catabolism of (R,S,)-[2-¹⁴C]-ABA, negating ABA-induced conversion to PA. Cycloheximide inhibited ABA biosynthesis and catabolism but did not affect ABA conjugation. Chloramphenicol and lincomycin had little or no effect on ABA metabolism suggesting that the enzymes involved were labile and cytoplasmic in origin. Ancymidol and cycocel inhibited ABA biosynthesis while AM01618 stimulated this process. The cytokinins, benzyladenine, kinetin, isopentenyl adenine and zeatin also inhibited ABA biosynthesis. These results are discussed in relation to the possible involvement of carotenoids in ABA biosynthesis. AM01618, ancymidol andcycocel did not significantly influence the conversion of ABA to PA and DPA while cytokinins appeared to enhance this process only in vegetative tissue. The information derived from these studies was then used in attempts to develop a cell-free system from higher plants capable of metabolising ABA. A cell-free system prepared from imbibed Hordeum vulgare cv. Dyan embryos biosynthesized and catabolised ABA. This is the first demonstration of a cell-free system from non-vegetative tissue capable of metabolising ABA and could prove useful for elucidating its biosynthetic route. This cell-free system generated the terpenyl pyrophosphates IPP, FPP and GGPP from MVA. ABA was produced from both MVA and IPP in the presence of 0₂ and NADPH. The biosynthesis of ABA was stimulated by the addition of the squalene 2,3-oxide cyclase and kaurene synthetase inhibitor, AM01618 and a "cold-pool trap" of (R,S,)-ABA. Ancymidol, cycocel and cytokinins reduced incorporation of label from MVA into ABA. Similar cell-free preparations, in the absence of AM01618, converted (R,S,)-[2-¹⁴-C]-ABA into PA, 7'-hydroxy ABA and water-soluble conjugates. Although the methyl ester of (R,S,)-ABA was efficiently hydrolysed in this cell-free system no DPA was generated. The possible involvement of mixed function oxidase activity and soluble oxidases is discussed in relation to ABA metabolism. While cell-free preparations from Persea americana cv. Fuerte mesocarp and immature seeds of Pisum sativum and Phaseolus vulgaris were unable to synthesize ABA from MVA, these tissue homogenates converted ABA into more polar acidic products. PA and DPA were identified as products of ABA catabolism in extracts from immature seeds of Phaseolus vulgaris and the l',4'-cis diol of ABA in extracts from Pisum sativum immature seeds
APA, Harvard, Vancouver, ISO, and other styles
3

Liang, Benjamin Ming-Hwa. "Organization and function of microtubules and their relationship /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841166.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Halls, Coralie Emilie. "Purification of a unique maturation enzyme involved in the processing of proaleurain." Online access for everyone, 2004. http://www.dissertations.wsu.edu/Dissertations/Spring2004/C%5FHalls%5F050704.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Zheng, Tao. "Investigation of plant tissue by environmental scanning electron microscopy." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609068.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Tegel, Friedrich. "Die Testaepidermis der Lactuceae (Asteraceae) ihre Diversität und systematische Bedeutung /." Connect to this title online, 2002. http://edoc.ub.uni-muenchen.de/archive/00000104/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Nogemane, Noluyolo. "Symplasmic pathway in phloem loading and unloading in source and sink leaves of Zea mays L. as evidenced under normal and elevated CO₂ conditions." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1007813.

Full text
Abstract:
Zea mays plants kept at ambient (ca 375ppm) and elevated CO₂ (ca 650 to 700ppm) were used to examine the possibility of a symplasmic loading, unloading and transport pathway in dark-adapted and illuminated (200μmolm⁻²sec⁻¹ ) sink and source leaves. 5,6-carboxyfluorescein diacetate was introduced into the mesophyll cells and symplasmic transfer observed 3h after application. In sink and source leaves exposed to ambient CO₂ and illuminated at 200 molm-2sec-1, the fluorescence front was observed approximately 3cm from the point of application, while in dark-adapted plants, the fluorescence front was observed approximately 1cm from the point of application. Under elevated CO₂ conditions the fluorescence front in illuminated plants appeared to transport faster moving approximately 5cm from the point of application, and in dark-adapted plants, only 3cm from the point of application. Based on the increase in 5,6-CF accumulation under elevated CO₂ conditions, the present study suggests that there was an increase in capacity for assimilate loading and transport under elevated CO₂ conditions. In source leaves, 5,6-CFDA was taken up into the mesophyll cells, loaded symplasmically and transported basipetally. In sink leaves 5,6- CFDA was taken up from basal mesophyll and after symplasmic loading, was transported acropetally where it was offloaded into the younger immature sink region. Transport in the sieve tubes was confirmed by using aniline blue, which was applied 3h after 5,6-CF transport. Aniline blue coupled with 5,6-CF transport studies showed that the sieve tubes of both cross and longitudinal veins are involved in symplasmic unloading, loading and transport processes in sink and source leaves. Apoplasmic uptake of 5,6-CFDA by cut leaves showed that after apoplasmic transport via the transpiration stream, 5,6-CFDA was offioaded to the xylem parenchyma where it was metabolically cleaved , releasing fluorescent 5,6-CF into the xylem parenchyma. Transverse sections cut after 3h of uptake were observed after 120 and 180 min suggesting that a retrieval of solutes occurs from the xylem to the xylem parenchyma, bundle sheath, phloem parenchyma and to the th in-walled sieve tubes. It was not possible to determine if the thick-walled sieve tubes were involved or if they took up 5,6-CF. Given the available data on loading and offioading of assimilates in sink and source leaves respectively, this study demonstrated that a slow symplasmic pathway exists from the mesophyll to the phloem, and that offloading from the phloem in sink leaves can occur via a symplasmic route.
APA, Harvard, Vancouver, ISO, and other styles
8

Chen, Wei. "Analysis of mass transport properties of plant cells by confocal microscopy and imaging techniques /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9953850.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Spokevicius, Antanas Vytas. "The use of induced somatic sectors for the elucidation of gene function and developmental patterns in xylogenic tissue /." Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00002300.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Mudiyanselage, Charith Malinga Rathnayaka. "Meshfree-based numerical modelling of three-dimensional (3-D) microscale deformations of plant food cells during drying." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/118069/1/Charith_Malinga_Rathnayaka_Mudiyanselage_Thesis.pdf.

Full text
Abstract:
Numerical modelling has been a helpful tool for analysing plant cellular structure and associated dynamics. It generally consumes less time, money and other resources compared to experimenting with real plant structures. In this context, investigating the morphological changes that take place in the plant cellular structure under different circumstances has recently been an important application. Drying is one of the most common and cost effective techniques for extending the shelf life of food-plant materials (for instance, fruits and vegetables). During the drying process, food-plant cellular structure undergoes structural deformations that influence drying operations in terms of performance as well as food quality. To engineer effective and efficient food drying processes, it is important to establish a good understanding of cell morphological changes and underlying mechanisms. Grid-based approaches and meshfree methods are the two main categories of numerical modelling techniques used to analyse food-plant drying phenomena. Grid-based methods encounter drawbacks in some applications due to the inherent 'grid' behaviour and subsequent inability to successfully model problems with large deformations and multiphase phenomena. To overcome these drawbacks, meshfree (or meshless) based numerical modelling and simulation methods have been developed. There are recently reported efforts to numerically model the micro mechanics of food-plant matter using coupled Smoothed Particle Hydrodynamics (SPH) and Discrete Element Method (DEM)-based approaches. Some of these studies focus only on fresh plant cellular structures and their behaviour under external mechanical loading. There are other studies considering both fresh and dried plant cellular structures in two dimensions (2-D) along with their morphological characteristics. The overall computational approach in those investigations show a promising capacity to be further extended towards more realistic scales. However, it is difficult to describe a truly 3-D phenomenon like cellular scale drying phenomena by means of a 2-D approach. Thus, in order to approximate the morphological changes of cellular scale food-plant drying phenomena in a more detailed manner, there is a requirement to extend that approach into the 3-D level. In addition, there are conceptual constraints in using the Discrete Element Method (DEM) to represent the cell wall membrane in a completely meshfree numerical model. The literature suggests that conceptually, a Coarse-Grained (CG) approach could be more suited for this application, as there is a stronger conceptual and fundamental matching in an SPH-CG coupling than in an SPH-DEM coupling. Within this background, this investigation aimed to develop a 3-D Smoothed Particle Hydrodynamics (SPH) and Coarse Grained method (CG) coupled numerical model, which could successfully approximate the morphological behaviour of foodplant cells during drying. Initially, the fundamentals of microscale plant cellular drying phenomena were studied. The applicability of a coupled SPH-CG 3-D approach was evaluated through a basic 3-D plant cell drying model. Next, an experimental investigation was carried out to observe the real morphological changes taking place in plant cellular structure during drying. Through the learning gleaned from both the basic numerical and experimental studies, an improved 3-D SPH-CG cell drying model was developed. The 3-D nature of this model allows it to predict the morphological changes on a more realistic scale compared to the previous 2-D models developed using a SPH-DEM coupling. The numerical results are found to be well comparable, both qualitatively and quantitatively, with the experimental findings. As the next step, the developed 3-D numerical approach was successfully applied to model different types of food-plant cells (e.g. apple, potato, grape and carrot). The agreement between the model predictions and the experimental findings was found to be favourable for all four food-plant categories selected. The 3-D SPH-CG numerical model investigated in this study can successfully model dryness states of food-plant cells in a larger moisture content range with stable results compared to the recently reported Finite Element Modelling (FEM)-based and meshfree-based plant cell drying models. The computational accuracy of the numerical modelling scheme has been maintained at a high value through limiting the percentage model consistency error to less than 1%. This developed 3-D model will provide a source of guidance for industrial practitioners to optimise food drying operations in terms of final product quality, nutritious value and overall process performance. In addition, the developed computational framework has potential future applications in modelling a wide range of plant cells and animal cells.
APA, Harvard, Vancouver, ISO, and other styles
11

Smith, Marthinus Luther. "Investigating the role of pyrophosphate fructose 6-phosphate 1-phosphotransferase in phloem loading." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1969.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Tunn, Ruth Elizabeth. "Expression of two-pore channels in mammalian primary cells and tissues, and their role in adipose tissue formation and function." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:6c0b970d-6133-4752-987a-e21f6e2dc69c.

Full text
Abstract:
Two-pore channels (TPCs, gene name Tpcn) have recently been identified as endolysosomal cation channels modulated by the potent calcium (Ca2+) releasing messenger nicotinic acid adenine dinucleotide phosphate (NAADP). Gene knockout (KO) and RNA knockdown studies have implicated TPCs in fundamental cellular processes, including secretion, of insulin in pancreatic islets, and differentiation, of skeletal myoblasts and osteoclasts. Investigations of Tpcn1 and Tpcn2 mRNA expression have indicated widespread tissue distribution, but a lack of suitable antibodies has impeded study of the endogenous proteins. In this study, an anti-TPC1 antibody was purified from immune sera and used in immunoblotting investigations to demonstrate TPC1 protein expression in a wide range of mouse tissues, with highest expression levels observed in kidney, liver and adipose tissue. Endogenous mouse TPC1 was demonstrated to be glycosylated, with apparent differences in the extent of glycosylation in different tissues based on the indicated molecular weight before and after treatment with a deglycosylating enzyme, which may have implications for the functional regulation of channel activity. Given the increasing prevalence of type 2 diabetes and obesity, an understanding of the molecular basis of glucose homeostasis and adipose tissue formation and function is an important scientific goal. Tpcn KO mice have been developed; in both Tpcn1 KOs and Tpcn2 KOs, impaired pancreatic β-cell Ca2+ signalling and reduced insulin secretion from the whole pancreas were demonstrated. However, the whole-animal phenotype has not been extensively researched. In this study, intraperitoneal glucose tolerance tests were conducted in Tpcn KO mice. These indicated that glucose homeostasis was not significantly affected in Tpcn2 KOs or Tpcn1/2 double KOs (DKOs), and only mildly impaired in Tpcn1 KOs, despite the defects previously observed at the cellular and tissue level. In addition, body composition was investigated in Tpcn1 KO, Tpcn2 KO and Tpcn1/2 DKO animals using magnetic resonance spectroscopy and time domain-nuclear magnetic resonance. Single Tpcn KOs were found to have lower adipose tissue levels as a percentage of body composition, while Tpcn1/2 DKOs were shown to have increased bodyweight but normal body composition. To investigate potential roles for TPCs in adipose tissue formation, Tpcn expression during adipogenesis was investigated using an in vitro multipotent mesenchymal stem cell line model of adipogenic differentiation. Tpcn2 mRNA levels were demonstrated by quantitative PCR to be transiently increased during the early stages of adipogenic differentiation, and cyclic AMP (cAMP) was identified as the factor that induced this upregulation. Lentiviruses were developed to express fluorescently-tagged TPCs, and overexpression of TPC2 was demonstrated to partially overcome the requirement for the cAMP-inducing agent in the medium used for the induction of adipogenesis. Collectively, these data suggest that TPCs may play a role in the formation and/or function of adipose tissue.
APA, Harvard, Vancouver, ISO, and other styles
13

Holden, Peter Richard. "Variability in cultured cells of Capsicum Spp." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/10960.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Kim, Yun Ju. "Forward genetic studies towards the understanding of the molecular mechanisms underlying floral meristem determinacy and small RNA function in Arabidopsis." Diss., [Riverside, Calif.] : University of California, Riverside, 2010. http://proquest.umi.com/pqdweb?index=0&did=2019822731&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1274208064&clientId=48051.

Full text
Abstract:
Thesis (Ph. D.)--University of California, Riverside, 2010.
Includes abstract. Title from first page of PDF file (viewed May 18, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
APA, Harvard, Vancouver, ISO, and other styles
15

Lappin, G. J. "The biotransformation of monoterpenoids by plant cells in axenic culture." Thesis, University of Westminster, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382797.

Full text
APA, Harvard, Vancouver, ISO, and other styles
16

Parker, Charlotte Clair. "The (bio)chemistry of cell adhesion in edible plant tissues : its role in texture." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327534.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Patil, Rajashekar M. "Tissue culture and transformation of rice (oryza sativa L.) using tobacco nurse cells /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09APSM/09apsmp298.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
18

Kirby, Nigel John. "An investigation of metabolite release from plant cells in vitro to their surrounding medium." Thesis, University of the West of England, Bristol, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329861.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

Abtahi, Seyed Ali. "Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc31522/.

Full text
Abstract:
In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency of 130 Hz. Initially high impedance of mutant sample tended to drop within 2 hours and finally approached the constant value which signified that the cell death mechanism was complete. However, the wildtype sample demonstrated approximately constant impedance (conductivity) during the experiment.
APA, Harvard, Vancouver, ISO, and other styles
20

Keller, Christopher Philip. "The role of polysaccharidases in acid wall loosening of epidermal tissue from young Phaseolus vulgaris L. hypocotyls." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26425.

Full text
Abstract:
The extension of frozen-thawed epidermal strips prepared from the first centimetre below the hypocotyl hook of six day old dark grown Phaseolus vulgaris seedlings while immersed in various buffers and under various tensions was characterized. This was done in an attempt to determine if the acid wall loosening phenomenon, which according to the Acid-growth theory (Taiz, 1984) is thought to mimic part of the auxin mechanism of action, is mediated by unspecified wall loosening enzymes. Epidermal strips were found to be significantly loosened by media pH 6.0 to pH 2.6 (0.05M citric acid-O.lOM disodium phosphate) relative to pH 7.5. A minimum stress between 1.6 and 7.6 grams was required for the acid-extension of strips 4.5±0.5 mm wide. Regardless of tension, extension by tissues in an acid medium was largely transient For example, tissues tensioned by a 16.0 gram load reached a maximum extension rate of 6.18 ±1.37% of initial length per hour (L°/hr) between 4 and 6 minutes after immersion in pH 4.8. The rate was 1.29±0.17% L°/hr between 55 and 60 minutes and 1.05±0.14% L°/hr between 220 and 240 minutes. Total acid-extension over four hours was 4.24±0.57% L°. The extension response was found to be stable; newly harvested tissues whether frozen or not performed similarly to strips aged up to 15 days at -12°C before being extended. The performance of strips immersed in unbuffered solutions indicated that tissues were self-buffering at an acid pH probably because of the fixed carboxyls within the wall. The capacity for acid-extension by epidermal strips was lost in mature tissues harvested 4-5 cm below the hypocotyl hook. Temperature coefficients from extension rates were determined at several pHs. The results were highly variable. The acid-extension of strips boiled 15 minutes in ethanol or extracted in 3M NaCl for 4 hours at 4°C or 6M LiCl for 8 hours was determined in several pHs. The impact of the treatments was largely a suppression of the initial burst of acceleration. Extension rates following the initial surge were relatively unaffected. Glycosidase activities in untreated, ethanol-boiled, or salt extracted strips were determined. β-glucosidase was found to be most active in untreated strips with lesser levels of β-galactosidase and β-xylosidase and a trace of α-galactosidase being detected. Ethanol-boiling and LiCl-extraction removed or deactivated all four activities from the strips and NaCl-extraction lowered all four activities 70-80%. NaCl proved to have solubilized most of the missing β-glucosidase and β-galactosidase when the extraction solution was assayed following desalting and concentration. LiCl solubilized most of β-xylosidase. It was concluded that glycosidases and any other similarly soluble enzyme cannot be responsible for long term acid wall loosening in bean epidermis. If an enzyme is involved, it must be extremely stable and tightly bound to the wall. The acid-extension performance of frozen-thawed longitudinally halved hypocotyl sections in comparison to epidermal strips, as well as other evidence was considered support for another hypothesized mechanism of acid wall loosening, the displacement of calcium bridges.
Science, Faculty of
Botany, Department of
Graduate
APA, Harvard, Vancouver, ISO, and other styles
21

Fialho, Larissa Caroline [UNESP]. "Identicação e caracterização de dois promotores de eucalipto: com padrão de expressão ubíquo e específico de câmbio." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/108486.

Full text
Abstract:
Made available in DSpace on 2014-08-13T14:50:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-16Bitstream added on 2014-08-13T18:01:28Z : No. of bitstreams: 1 000747183_20150516.pdf: 388655 bytes, checksum: 28bb4ca0fd35b64c1425eeff151db6dc (MD5) Bitstreams deleted on 2015-05-19T12:01:09Z: 000747183_20150516.pdf,Bitstream added on 2015-05-19T12:01:40Z : No. of bitstreams: 1 000747183.pdf: 1675711 bytes, checksum: 172952b37ea05e8baceeccb4e6e6ea8f (MD5)
A franca expansão das florestas de eucalipto observada nos últimos anos em diferentes estados brasileiros aumentou a dependência tecnológica da cultura, tornando necessária a sua inserção no contexto biotecnológico. Para tal, a disponibilidade de ferramentas moleculares que viabilizem a produção de árvores geneticamente modificadas se faz necessária. Nesse contexto, o presente trabalho visou validar funcionalmente dois promotores de Eucalyptus grandis, o primeiro relacionado a um gene que codifica uma Lacase (denominado EgLac) com expressão específica em caule (câmbio), e o segundo relacionado a uma actina (denominado EgAct) com expressão ubíqua. Um cassete de expressão contendo o promotor EgLac em fusão transcricional com o gene repórter GUS (previamente construído) foi inserido em plantas de Arabidopsis thaliana, e uma expressão vascular foi constatada em testes histoquímicos. Em cortes histológicos observou-se que a expressão de GUS ficou restrita ao floema de raízes e folhas. Em paralelo, o gene EgAct teve a sua expressão ubíqua validada em diferentes órgãos/tecidos de eucalipto, e a sua região promotora foi amplificada. Um cassete de expressão contendo o promotor EgAct em fusão ao repórter GUS foi igualmente inserido em plantas de A. thaliana. Análises histoquímicas revelaram uma expressão vascular do gene repórter distribuída ao longo de toda a planta. Por outro lado, a quantificação da expressão de GUS em plantas transformadas revelaram níveis variáveis de acumulação de transcrição de acordo com a idade e o órgão/tecido analisado
The rapid expansion of eucalyptus plantations observed in recent years in different Brazilian states increased the technological dependence of the culture, and its inclusion in the biotechnological context is an urgent need. For this, the availability of molecular tools that enable the production of genetically modified trees is necessary. In this context, the present work aimed to functionally characterize two promoters of Eucalyptus grandis, the first one related to a gene encoding a laccase (called EgLac) with specific expression in stem (cambium region), and the second one related to a gene encoding an ubiquitously expressed actin (called EgAct). An expression cassette containing the EgLac promoter transcriptionally fused to the GUS reporter gene was inserted into Arabidopsis thaliana, and a vascular expression pattern was observed in histochemical tests. Histological sections showed that GUS expression was restricted to the phloem of roots and leaves. In parallel, the ubiquitous expression of EgAct was validated using different eucalyptus organs/tissues, and its promoter region was amplified. An expression cassette containing the EgAct promoter fused to the GUS reporter was also inserted into A. thaliana. Histochemical analysis revealed a vascular expression of the reporter gene distributed throughout the plant. Moreover, quantification of GUS expression in transformed plants revealed variable levels of transcript accumulation according to the age and organ/tissue analyzed
APA, Harvard, Vancouver, ISO, and other styles
22

Fialho, Larissa Caroline. "Identicação e caracterização de dois promotores de eucalipto : com padrão de expressão ubíquo e específico de câmbio /." Botucatu, 2013. http://hdl.handle.net/11449/108486.

Full text
Abstract:
Orientador: Ivan de Godoy
Banca: Celso Luis Marino
Banca: Márcio José da Silva
Resumo: A franca expansão das florestas de eucalipto observada nos últimos anos em diferentes estados brasileiros aumentou a dependência tecnológica da cultura, tornando necessária a sua inserção no contexto biotecnológico. Para tal, a disponibilidade de ferramentas moleculares que viabilizem a produção de árvores geneticamente modificadas se faz necessária. Nesse contexto, o presente trabalho visou validar funcionalmente dois promotores de Eucalyptus grandis, o primeiro relacionado a um gene que codifica uma Lacase (denominado EgLac) com expressão específica em caule (câmbio), e o segundo relacionado a uma actina (denominado EgAct) com expressão ubíqua. Um cassete de expressão contendo o promotor EgLac em fusão transcricional com o gene repórter GUS (previamente construído) foi inserido em plantas de Arabidopsis thaliana, e uma expressão vascular foi constatada em testes histoquímicos. Em cortes histológicos observou-se que a expressão de GUS ficou restrita ao floema de raízes e folhas. Em paralelo, o gene EgAct teve a sua expressão ubíqua validada em diferentes órgãos/tecidos de eucalipto, e a sua região promotora foi amplificada. Um cassete de expressão contendo o promotor EgAct em fusão ao repórter GUS foi igualmente inserido em plantas de A. thaliana. Análises histoquímicas revelaram uma expressão vascular do gene repórter distribuída ao longo de toda a planta. Por outro lado, a quantificação da expressão de GUS em plantas transformadas revelaram níveis variáveis de acumulação de transcrição de acordo com a idade e o órgão/tecido analisado
Abstract: The rapid expansion of eucalyptus plantations observed in recent years in different Brazilian states increased the technological dependence of the culture, and its inclusion in the biotechnological context is an urgent need. For this, the availability of molecular tools that enable the production of genetically modified trees is necessary. In this context, the present work aimed to functionally characterize two promoters of Eucalyptus grandis, the first one related to a gene encoding a laccase (called EgLac) with specific expression in stem (cambium region), and the second one related to a gene encoding an ubiquitously expressed actin (called EgAct). An expression cassette containing the EgLac promoter transcriptionally fused to the GUS reporter gene was inserted into Arabidopsis thaliana, and a vascular expression pattern was observed in histochemical tests. Histological sections showed that GUS expression was restricted to the phloem of roots and leaves. In parallel, the ubiquitous expression of EgAct was validated using different eucalyptus organs/tissues, and its promoter region was amplified. An expression cassette containing the EgAct promoter fused to the GUS reporter was also inserted into A. thaliana. Histochemical analysis revealed a vascular expression of the reporter gene distributed throughout the plant. Moreover, quantification of GUS expression in transformed plants revealed variable levels of transcript accumulation according to the age and organ/tissue analyzed
Mestre
APA, Harvard, Vancouver, ISO, and other styles
23

Smith, Aaron. "Vertex model approaches to epithelial tissues in developmental systems." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:4d19f232-764c-4e27-bca9-d2ede0ec2db9.

Full text
Abstract:
The purpose of this thesis is to develop a vertex model framework that can be used to perform computational experiments related to the dynamics of epithelial tissues in developmental systems. We focus on three example systems: the Drosophila wing imaginal disc, the Drosophila epidermis and the visceral endoderm of the mouse embryo. Within these systems, key questions pertaining to size-control mechanisms and coordination of cell migration remain unanswered and are amenable to computational testing. The vertex model presented here builds upon existing frameworks in three key ways. Firstly, we include novel force terms, representing, for example, the reaction of a cell to being compressed and its shape becoming distorted during a highly dynamic process such as cell migration. Secondly, we incorporate a model of diffusing morphogenetic growth factors within the vertex framework, using an arbitrary Lagrangian-Eulerian formulation of the diffusion equation and solving with the finite-element method (FEM). Finally, we implement the vertex model on the surface of an ellipsoid, in order to simulate cell migration in the mouse embryo. Throughout this thesis, we validate our model by running simple simulations. We demonstrate convergence properties of the FEM scheme and discuss how the time taken to solve the system scales with tissue size. The model is applied to biological systems and its utility demonstrated in several contexts. We show that when growth is dependent on morphogen concentration in the Drosophila wing disc, proliferation occurs preferentially in regions of high concentration. In the Drosophila epidermis, we show that a recently proposed mechanism of compartment size-control, in which a growth-factor is released in limited amounts, is viable. Finally, we examine the phenomenon of rosettes in the mouse embryo, which occur when five or more cells meet at a common vertex. We show, by running simulations both with and without rosettes, that they are crucial facilitators of ordered migration, and are thus critical in the patterning of the early embryo.
APA, Harvard, Vancouver, ISO, and other styles
24

Iannello, Carmelina <1981&gt. "Pharmacological screening and biotecnological production of alkaloids from tissues and cells cultured by plants of the Amaryllidaceae family." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6579/1/Tesi_Dottorato_Carmelina_Iannello.pdf.

Full text
Abstract:
In this work particular attention was given to the study of secondary metabolites produced by some plants belonging to the Amaryllidaceae family, in the specific case isoquinoline alkaloids. At the first instance were characterized both qualitatively and quantitatively three different plants belonging to Amaryllidaceae family, such as: Crinum angustum Steud., Pancratium illyricum L., and Leucojum nicaeense Ard. The alkaloids extracts obtained were separately tested against enzymes involved in specific diseases or liable in multifactorial pathologies, like: MMPs, AChE,and PPO. From leaves extract of P.illyricum was isolated a new compound, 11α-hydroxy-O-methylleucotamine, with important role in AChE inbition. Considering the protection role against external bodies carried out by these metabolites in plant, extracts were also assayed against ATCC microorganisms and clinical isolates. Plants with promising pharmacological activities have been the basis for development of in vitro plant models.
APA, Harvard, Vancouver, ISO, and other styles
25

Iannello, Carmelina <1981&gt. "Pharmacological screening and biotecnological production of alkaloids from tissues and cells cultured by plants of the Amaryllidaceae family." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6579/.

Full text
Abstract:
In this work particular attention was given to the study of secondary metabolites produced by some plants belonging to the Amaryllidaceae family, in the specific case isoquinoline alkaloids. At the first instance were characterized both qualitatively and quantitatively three different plants belonging to Amaryllidaceae family, such as: Crinum angustum Steud., Pancratium illyricum L., and Leucojum nicaeense Ard. The alkaloids extracts obtained were separately tested against enzymes involved in specific diseases or liable in multifactorial pathologies, like: MMPs, AChE,and PPO. From leaves extract of P.illyricum was isolated a new compound, 11α-hydroxy-O-methylleucotamine, with important role in AChE inbition. Considering the protection role against external bodies carried out by these metabolites in plant, extracts were also assayed against ATCC microorganisms and clinical isolates. Plants with promising pharmacological activities have been the basis for development of in vitro plant models.
APA, Harvard, Vancouver, ISO, and other styles
26

Mahnic̆-Kalamiza, Samo. "Effects of electrical and thermal pre-treatment on mass transport in biological tissue." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2247/document.

Full text
Abstract:
Le champ électrique d'une puissance suffisante peut provoquer une augmentation de conductivité et perméabilité de la membrane cellulaire. L'effet est connu comme l'électroporation, attribuée à la création de voies aqueuses dans la membrane. Quantifier le transport de la matière dans le cadre d'électroporation est un objectif important. Comprendre ces processus a des ramifications dans l’extraction du jus ou l’extraction sélective des composés de cellules végétales, l'amélioration de l'administration de médicaments, et des solutions aux défis environnementaux. Il y a un manque de modèles qui pourraient être utilisés pour modéliser le transport de la matière dans les structures complexes (tissus biologiques) par rapport à l'électroporation. Cette thèse présente une description mathématique théorique (un modèle) pour étudier le transport de la matière et le transfert de la chaleur dans tissu traité par l’électroporation. Le modèle a été développé en utilisant les lois de conservation et de transport et permet le couplage des effets de l'électroporation sur la membrane des cellules individuelles au transport de la matière ou la chaleur dans le tissu. Une solution analytique a été trouvée par une simplification, mais le modèle peut être étendu avec des dépendances fonctionnelles supplémentaires et résolu numériquement. La thèse comprend cinq articles sur l'électroporation dans l'industrie alimentaire, la création de modèle pour le problème de diffusion, la traduction du modèle au problème lié à l’expression de jus, validation du modèle, ainsi que des suggestions pour une élaboration future du modèle. Un chapitre supplémentaire est dédié au transfert de la chaleur dans tissu
An electric field of sufficient strength can cause an increase of conductivity and permeability of cell membrane. Effect is known as electroporation and is attributed to creation of aqueous pathways in the membrane. Quantifying mass transport in connection with electroporation of biological tissues is an important goal. The ability to fully comprehend transport processes has ramifications in improved juice extraction and improved selective extraction of compounds from plant cells, improved drug delivery, and solutions to environmental challenges. While electroporation is intensively investigated, there is a lack of models that can be used to model mass transport in complex structures such as biological tissues with relation to electroporation. This thesis presents an attempt at constructing a theoretical mathematical description – a model, for studying mass (and heat) transfer in electroporated tissue. The model was developed employing conservation and transport laws and enables coupling effects of electroporation to the membrane of individual cells with the resulting mass transport or heat transfer in tissue. An analytical solution has been found though the model can be extended with additional dependencies to account for the phenomenon of electroporation, and solved numerically. Thesis comprises five peer-reviewed papers describing electroporation in the food industry, model creation for the problem of diffusion, translation of the model to the mathematically-related case of juice expression, model validation, as well as suggestions for possible future development, extension, and generalization. An additional chapter is dedicated to transfer of heat in tissue
APA, Harvard, Vancouver, ISO, and other styles
27

Fei, Liwen. "Towards automating micropropagation: from cells to shoots to plants in one step." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/195.

Full text
Abstract:
A mist reactor was used to study plant growth and development under various environmental conditions towards the production of healthy plantlets ready for soil transplant in one step from inoculation. In addition, a 3D type of cultivation via surface attachment of explants to vertically hanging strips inside the mist reactor was also investigated to maximize productivity with minimal footprint. Using carrot as the model species, pre-embryogenic cell suspensions were successfully spray-inoculated onto hanging poly-L-lysine (PLL)-coated nylon mesh to which they then attached and remained for several weeks while they developed into rooted plantlets. To study single step micropropagation from shoot explants to fully acclimatized plantlets, Artemisia annua was used as the model species. Nodal cuttings of A. annua were inoculated onto PLL-coated mesh strips by briefly immersing the strips in the suspension of nodal cuttings. Investigation of medium, phytohormones, CO2, ventilation level and humidity ensued resulting in selection of a preferred final process that reduced physiological aberrations like hyperhydricity and was time efficient. The nodal cuttings that attached to the strips were first misted with half strength shooting medium for 7 days to develop new shoots. Then the new shoots were misted with the rooting medium supplemented with NAA for 12 days to develop roots. Rooted plantlets were acclimatized in the same rooting medium for 9 days to acquire fully functional stomata prior to planting into soil. Taken together this study suggested that fully developed plantlets ready for planting into soil could be obtained in a single step in a bioreactor from embryogenic cells or from nodal explants.
APA, Harvard, Vancouver, ISO, and other styles
28

Özcan, Sebahattin. "Tissue culture in pea and engineering a marker gene for specific expression in target cells for plant transformation." Thesis, University of Leicester, 1993. http://hdl.handle.net/2381/35334.

Full text
APA, Harvard, Vancouver, ISO, and other styles
29

Karunasena, H. C. P. "Numerical simulation of micro-scale morphological changes of plant food materials during drying: A meshfree approach." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/76526/1/H.C.P.%20Karunasena%20Thesis.pdf.

Full text
Abstract:
This thesis developed a high preforming alternative numerical technique to investigate microscale morphological changes of plant food materials during drying. The technique is based on a novel meshfree method, and is more capable of modeling large deformations of multiphase problem domains, when compared with conventional grid-based numerical modeling techniques. The developed cellular model can effectively replicate dried tissue morphological changes such as shrinkage and cell wall wrinkling, as influenced by moisture reduction and turgor loss.
APA, Harvard, Vancouver, ISO, and other styles
30

Fang, Jingjing [Verfasser], Jonathan [Akademischer Betreuer] Gershenzon, Bernd [Akademischer Betreuer] Schneider, and Peter [Akademischer Betreuer] Spiteller. "Analysis of plant secondary metabolites from specialized organs, tissue and cells / Jingjing Fang. Gutachter: Jonathan Gershenzon ; Bernd Schneider ; Peter Spiteller." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2013. http://d-nb.info/103366989X/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

He, Bai-sen. "Osmotic dehydration in plant tissues." Thesis, Aston University, 2005. http://publications.aston.ac.uk/12236/.

Full text
Abstract:
The primary aim of the thesis is to provide a comprehensive investigation of the osmotic dehydration processes in plant tissue. Effort has been concentrated on the modelling for simulating the processes. Two mathematical models for simulating the mass transfer during osmotic dehydration processes in plant tissues are developed and verified using existing experimental data. Both models are based on the mechanism of diffusion and convection of any mobile material that can transport in plant tissues. The mass balance equation for the transport of each constituent is established separately for intracellular and extra-cellular volumes with taking into account the mass transfer across the cell membrane the intracellular and extra-cellular volumes and the shrinkage of the whole tissue. The contribution from turgor pressure is considered in both models. Model two uses Darcy’s law to build the relation between shrinkage velocity and hydrostatic pressure in each volume because the plant tissue can be considered as the porous medium. Moreover, it has been extended to solve the multi-dimensional problems. A lot of efforts have been made to the parameter study and the sensitivity analyses. The parameters investigated including the concentration of the osmotic solution, diffusion coefficient, permeability of the cell membrane, elastic modulus of the cell wall, critical cell volume etc. The models allow us to quantitatively simulate the time evolution of intracellular and extra-cellular volumes as well as the time evolution of concentrations in each cross-section.
APA, Harvard, Vancouver, ISO, and other styles
32

Merkel, Matthias. "From cells to tissues." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-156597.

Full text
Abstract:
An essential prerequisite for the existence of multi-cellular life is the organization of cells into tissues. In this thesis, we theoretically study how large-scale tissue properties can emerge from the collective behavior of individual cells. To this end, we focus on the properties of epithelial tissue, which is one of the major tissue types in animals. We study how rheological properties of epithelia emerge from cellular processes, and we develop a physical description for the dynamics of an epithelial cell polarity. We apply our theoretical studies to observations in the developing wing of the fruit fly, Drosophila melanogaster. In order to study epithelial mechanics, we first develop a geometrical framework that rigorously describes the deformation of two-dimensional cellular networks. Our framework decomposes large-scale deformation into cellular contributions. For instance, we show how large-scale tissue shear decomposes into contributions by cell shape changes and into contributions by different kinds of topological transitions. We apply this framework in order to quantify the time-dependent deformation of the fruit fly wing, and to decompose it into cellular contributions. We also use this framework as a basis to study large-scale rheological properties of epithelia and their dependence on cellular fluctuations. To this end, we represent epithelial tissues by a vertex model, which describes cells as elastic polygons. We extend the vertex model by introducing fluctuations on the cellular scale, and we develop a method to perform perpetual simple shear simulations. Analyzing the steady state of such simple shear simulations, we find that the rheological behavior of vertex model tissue depends on the fluctuation amplitude. For small fluctuation amplitude, it behaves like a plastic material, and for high fluctuation amplitude, it behaves like a visco-elastic fluid. In addition to analyzing mechanical properties, we study the reorientation of an epithelial cell polarity. To this end, we develop a simple hydrodynamic description for polarity reorientation. In particular, we account for polarity reorientation by tissue shear, by another polarity field, and by local polarity alignment. Furthermore, we develop methods to quantify polarity patterns based on microscopical images of the fly wing. We find that our hydrodynamic description does not only account for polarity reorientation in wild type fly wings. Moreover, it is for the first time possible to also account for the observed polarity patterns in a number of genetically altered flies
Eine wesentliche Voraussetzung für die Existenz mehrzelligen Lebens ist, dass sich einzelne Zellen sinnvoll zu Geweben ergänzen können. In dieser Dissertation untersuchen wir, wie großskalige Eigenschaften von Geweben aus dem kollektiven Verhalten einzelner Zellen hervorgehen. Dazu konzentrieren wir uns auf Epitheliengewebe, welches eine der Grundgewebearten in Tieren darstellt. Wir stellen theoretische Untersuchungen zu rheologischen Eigenschaften und zu zellulärer Polarität von Epithelien an. Diese theoretischen Untersuchungen vergleichen wir mit experimentellen Beobachtungen am sich entwickelnden Flügel der schwarzbäuchigen Taufliege (Drosophila melanogaster). Um die Mechanik von Epithelien zu untersuchen, entwickeln wir zunächst eine geometrische Beschreibung für die Verformung von zweidimensionalen zellulären Netzwerken. Unsere Beschreibung zerlegt die mittlere Verformung des gesamten Netzwerks in zelluläre Beitrage. Zum Beispiel wird eine Scherverformung des gesamten Netzwerks auf der zellulären Ebene exakt repräsentiert: einerseits durch die Verformung einzelner Zellen und andererseits durch topologische Veränderungen des zellulären Netzwerks. Mit Hilfe dieser Beschreibung quantifizieren wir die Verformung des Fliegenflügels während des Puppenstadiums. Des Weiteren führen wir die Verformung des Flügels auf ihre zellulären Beiträge zurück. Wir nutzen diese Beschreibung auch als Ausgangspunkt, um effektive rheologische Eigenschaften von Epithelien in Abhängigkeit von zellulären Fluktuationen zu untersuchen. Dazu simulieren wir Epithelgewebe mittels eines Vertex Modells, welches einzelne Zellen als elastische Polygone abstrahiert. Wir erweitern dieses Vertex Modell um zelluläre Fluktuationen und um die Möglichkeit, Schersimulationen beliebiger Dauer durchzuführen. Die Analyse des stationären Zustands dieser Simulationen ergibt plastisches Verhalten bei kleiner Fluktuationsamplitude und visko-elastisches Verhalten bei großer Fluktuationsamplitude. Neben mechanischen Eigenschaften untersuchen wir auch die Umorientierung einer Zellpolarität in Epithelien. Dazu entwickeln wir eine einfache hydrodynamische Beschreibung für die Umorientierung eines Polaritätsfeldes. Wir berücksichtigen dabei insbesondere Effekte durch Scherung, durch ein anderes Polaritätsfeld und durch einen lokalen Gleichrichtungseffekt. Um unsere theoretische Beschreibung mit experimentellen Daten zu vergleichen, entwickeln wir Methoden um Polaritätsmuster im Fliegenflügel zu quantifizieren. Schließlich stellen wir fest, dass unsere hydrodynamische Beschreibung in der Tat beobachtete Polaritätsmuster reproduziert. Das gilt nicht nur im Wildtypen, sondern auch in genetisch veränderten Tieren
APA, Harvard, Vancouver, ISO, and other styles
33

Watson, L. D. "Induction and assessment of plant cell membrane permeability." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233331.

Full text
Abstract:
This thesis describes the isolation, immobilisation and permeabilisation of Digitalis lanata (foxglove) and Nicotiana tabacum (tobacco) plant cells and protoplasts. Protoplasts were isolated from leaves of Digitalis lanata and Nicotiana tabacum and cultured in conditions of varying osmotic potential, illumination and cell density in order to achieve maximum cell stability. The regeneration of cellulose cell walls in Nicotiana tabacum protoplasts could be inhibited by the addition of dilute concentrations of the herbicide 2,6-Dichlorobenzonitrile. At concentrations of 2-10 mg/l in culture medium cell wall regeneration could be prevented for up to 6-8 weeks. Isolated cells and protoplasts were stabilised by entrapment within a beaded agarose support matrix. Nicotiana tabacum protoplasts and cells, immobilised within an agarose beaded support matrix were used to develop a technique to permeabilise and destabilise the cell membranes. Cells or protoplasts pre-loaded with 6-Carboxy-Fluorescein, Neutral Red stains and 14C-Sucrose or 86Rb+ radioactive tracers were employed as markers for cell permeability or leakiness. Efflux or Compartmental analysis was used to determine the influence of various selected permeabilising agents on the integrity and the leakiness of either protoplast or cell membranes. Immobilised protoplasts or cells were subjected to a three - step procedure involving initial loading with 86Rb+ tracer, a membrane permeabilisation step and finally a recovery step. Protoplast membrane stability could not be regained after the recovery step, following a 30 minute period of permeabilisation with 50 mM acetic acid in culture medium. Immobilised cells could, however, regain membrane integrity with good intracellular retention of 86Rb+ tracer ion during the efflux experiment. Thus, immobilised Nicotiana tabacum cells could be made reversibly permeable with the use of specific agents. It is anticipated that such techniques which encourage reversible permeabilisation of immobilised cells have potential in larger scale plant cell culture systems to effect the release of intracellularly stored, useful secondary metabolites. There are also possibilities for the inclusion of exogenous precursors, cofactors and foreign genetic material which would increase compound yield and may produce novel secondary metabolites.
APA, Harvard, Vancouver, ISO, and other styles
34

Hammad, Mira. "Reconstruction of auricular cartilage using natural-derived scaffolds with an in vivo application in rabbit model Effects of hypoxia on chondrogenic differentiation of progenitor cells from different origins Cell sheets as tools for ear cartilage reconstruction in vivo Cartilage tissue engineering using apple cellulosic scaffolds Cell-secreted matrices as cell supports: Novel approaches for cell culture applications." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC404.

Full text
Abstract:
La reconstruction des défauts du cartilage auriculaire nécessite une restauration appropriée par des sources cellulaires adéquates ainsi que la fourniture de supports appropriés pour les tissus. Ce travail visait à étudier différents échafaudages et biomatériaux pour l'ingénierie in vitro du cartilage auriculaire ainsi que la réparation in vivo du cartilage auriculaire chez des modèles de lapin. Nous avons d'abord montré que les périchondrocytes auriculaires sont les meilleurs candidats pour la régénération du cartilage auriculaire et que l'hypoxie n'est pas nécessaire à leur différenciation chondrogénique. Ces cellules ont formé avec succès des feuillets de cellules cartilagineuses que nous avons utilisés pour régénérer le tissu cartilagineux in vitro et pour combler et reconstruire les défauts du cartilage in vivo dans des modèles allogèniques de lapins. Nous avons ensuite testé des tissus dérivés de la cellulose en décellularisant un tissu de pomme. Une fois recolonisés avec des cellules, ces échafaudages ont surpassé les hydrogels d'alginate en augmentant la croissance et en régulant l'expression cartilagineuse dans différentes cellules de mammifères. Dans la dernière partie de la thèse, nous avons examiné des matrices sécrétées par les cellules et les avons utilisées comme revêtement pour différentes applications de culture cellulaire. Il est intéressant de noter que ces supports, une fois lyophilisés, ont favorisé la culture de cellules allo- et xénogéniques, augmenté la prolifération et stimulé la chondrogenèse. Nous avons également mis en évidence la préservation du phénotype lors de l’amplification des chondrocytes par passages successifs. Notre étude fournit de nouveaux outils et approches pour de multiples applications de culture cellulaire
Successful reconstruction of auricular cartilage defects requires the appropriate restoration of the cartilaginous deformities by potential cell sources as well as providing suitable tissue supports. This work aimed to investigate different scaffolds and biomaterials for in vitro auricular cartilage engineering as well as in vivo auricular cartilage repair in rabbit models. We first showed that auricular perichondrocytes are the best candidates for auricular cartilage regeneration and hypoxia is not necessary for their chondrogenic differentiation. These cells successfully formed cartilaginous cell sheets which were used to regenerate cartilage tissue in vitro and to fill and reconstruct cartilage defects in vivo in allogenic rabbit models. Furthermore, we tested cellulose-derived tissue by decellularizing apple tissue and its use as a scaffold. Repopulated with cells, these scaffolds surpassed alginate hydrogels by enhancing colonization and upregulating the cartilaginous expression in different mammalian cells. In the final part of the thesis, we examined cell-secreted matrices and used them as a coating for different cell culture applications. Interestingly, these coatings promoted both allo- and xenogeneic cell culture, increased proliferation, and boosted chondrogenesis. We also highlighted phenotype preservation during chondrocytes expansion on these cell-secreted matrices. Our study provides novel tools and approaches for multiple cell culture applications
APA, Harvard, Vancouver, ISO, and other styles
35

Stuhlen, Birgit. "The mechanical design of turgid plant tissues." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312582.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

Potter, Ian. "Xyloglucan endotransglycosylase activity in growing plant tissues." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/12132.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Cheung, Chun Yue Maurice. "Genome scale metabolic models of plant tissues." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:9a2af288-848c-48fc-94e7-343bbc732645.

Full text
Abstract:
The aim of this thesis was to explore the use of genome-scale metabolic models to predict metabolic fluxes in plant tissues. Results from this thesis showed that the application of constraint-based modelling, namely flux balance analysis, to an Arabidopsis genome-scale metabolic model gave accurate predictions of metabolic fluxes in heterotrophic cell culture and in photosynthetic leaves. Two major factors important for the accuracy of model predictions were highlighted from the study: 1) the inclusion of energetic costs for transports and cellular maintenance in terms of ATP and NADPH; 2) consideration of the interactions between light and dark metabolism in modelling photosynthetic leaves. This study began with the construction of a well-curated and compartmented genome-scale metabolic model of Arabidopsis. Using the model, cellular maintenance costs in a heterotrophic cell culture under control and two stress conditions were estimated in terms of ATP and reductant usage. The results suggested that the cells were not stressed under hyperosmotic conditions. Comparisons between model predictions and experimentally estimated flux maps showed that the inclusion of transport and maintenance costs was important for obtaining accurate model flux predictions. To model leaf metabolism over a day-night cycle, a diel modelling framework was developed which took into account the interactions between light and dark metabolism. Numerous known features of metabolism in a C3 leaf were predicted such as the nocturnal accumulation of citrate utilised for diurnal glutamate and glutamine synthesis and the operation of an incomplete TCA cycle during the day. Using the Arabidopsis genome-scale metabolic model and the diel modelling framework, the operation of the CAM cycle was predicted as a direct consequence of blocking the CO2 exchange with the external air during the day to simulate closure of the stomata. Comparisons between model predictions of C3 and various subtypes of CAM leaves suggested that photon and nitrogen use efficiencies are unlikely to be the driving forces for the evolution of CAM plants under the current atmospheric CO2 concentration. Finally, the model was utilised to predict the changes in metabolic fluxes, in particular fluxes through various routes of alternative electron flow, in a C3 leaf with varying light intensity, nitrogen availability and at different stages of leaf development. From the model flux predictions, it was shown that constraint-based modelling can be utilised to elucidate the distinct metabolic roles of enzymes in different subcellular compartments and the tissue-specific use of distinct forms of enzymes with different coenzyme specificities.
APA, Harvard, Vancouver, ISO, and other styles
38

Kramm, Anneke. "Identification and characterisation of epigenetic mechanisms in osteoblast differentiation of human mesenchymal stem cells." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:b6f7a356-b20f-4988-8770-8bebc233bf4b.

Full text
Abstract:
A major therapeutic challenge in musculoskeletal regenerative medicine is how to effectively replenish bone tissue lost due to pathological conditions such as fracture, osteoporosis, or rheumatoid arthritis. Mesenchymal stem cells are currently investigated for applications in bone-tissue engineering and human bone marrow-derived mesenchymal stem cells (hMSCs) could be a promising source for generation of tissue-engineered bone. However, the therapeutic potential of MSCs has not been fully exploited due to a lack of knowledge regarding the identity, nature, and differentiation of hMSCs. Epigenetic mechanisms regulating the chromatin structure as well as specific gene transcription are crucial in determination of stem cell differentiation. With the aim to systematically identify epigenetic factors that modulate MSC differentiation, the work in this thesis encompasses an approach to identify epigenetic mechanisms underlying, initiating, and promoting osteoblast differentiation, and the investigation of individual epigenetic modulators. Various osteogenic inducers were validated for differentiation of MSCs and an assay allowing assessment of differentiation outcome was developed. This assay was subsequently employed in knockdown experiments with lentiviral short hairpin RNAs and inhibitor screens with small molecules targeting putative druggable epigenetic modulator classes. This approach identified around 100 epigenetic modulator candidates involved in osteoblast differentiation, of these candidates approximately 2/3 downregulated and 1/3 upregulated alkaline phosphatase (ALP) activity. Serving as a proof-of-concept, orthogonal validation experiments employing locked nucleic acid (LNA) knockdown were performed to validate a subset of candidates. Two identified target genes were selected for further investigation. Bromodomain-containing protein 4 (BRD4) was identified as one component of epigenetic regulation; its inhibition led to a decrease in ALP expression, downregulation of key osteoblast transcription factors Runx2 and Osterix, as well as impaired bone matrix formation. Knockdown of lysine (K)-specific demethylase 1A (KDM1A/LSD1) upregulated ALP activity and treatment with a small molecule inhibitor targeting KDM1A led to an increase in ALP, RUNX2, and bone sialoprotein expression. Intriguingly, in a transgenic mouse model overexpressing Kdm1a a decrease in bone volume and bone mineral density was observed, thus supporting the hypothesis that KDM1A is a central regulator of osteoblast differentiation.
APA, Harvard, Vancouver, ISO, and other styles
39

Mlungwana, Asanda. "In-vitro propagation studies of the endangered succulents Drosanthemum Micans and Drosanthemum Hallii (Aizoaceae)." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2748.

Full text
Abstract:
Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018.
Drosanthemum micans and Drosanthemum hallii are endangered succulent shrubs of horticultural and medicinal value. They are restricted to the Succulent Karroo, which is one of the world’s biodiversity hotspots. The species risk extinction from illegal over-harvesting for water-wise gardens, erosion by occasional flush floods from ephemeral rivers, competition from alien invasive species, overgrazing and clearing of land for agriculture and human settlement. Although seeds and cuttings may be used in propagating these species, they often require seasonal collection and planting and cuttings struggle to establish, hence the need for in-vitro propagation as an alternative solution. Thus, the main objective of the study was to develop a method for rapid in-vitro shoot and root multiplication and acclimatization of D. micans and D. hallii. To initiate shoot formation, disinfected leaf and stem nodal explants were cultured in Murashige and Skoog (1962) media supplemented with different rates (0, 10, 20 or 30μM) of 2-isopentyladenine, 6-Benzyladenine and kinetin for D. hallii or 2-isopentyladenine, 6-Benzyladenine and Thiadiazuron for D. micans. Shoots from explants were rooted in varying rates (0, 10, 20 or 30μM) of IAA for root initiation. Three media, which were used in previous studies, were tested for acclimatization of rooted explants in i) vermiculite, ii) sand (50%): vermiculite (50%) or iii) sand (75%): perlite (25%). For quantitative evaluation of plant stress, chlorophyll fluorescence index (Fv/Fm) was measured as a proxy for plant stressf stress. It emerged that stem nodal explants of D. hallii tend to produce multiple shoots whilst leaf explants tended to produce callus when cultured in full-strength Murashige and Skoog (1962). Shoot multiplication was optimal in both D. hallii and D. micans at 10 μM of kinetin. Root formation in both D. hallii and D. micans only occurred when shoots were transferred to a full-strength Murashige and Skoog (1962) media without any phytohormones added. The intensity of tissue browning increased at higher levels of cytokinins, suggesting an interaction of plant growth regulators with exudates from explants. Different acclimatization media tested showed no significant differences in the level of stress (Fv/Fm). It is recommended that Murashige and Skoog (1962) media with10 μM kinetin be used for shoot development and multiplication, followed by transfer of the shoots to fresh full-strength Murashige and Skoog (1962) media without hormones for root development. Acclimatization of the rooted explants was possible in one of the following media: i) vermiculite, ii) sand (50%): vermiculite (50%) or iii) sand (75%): perlite (25%) and in a misted greenhouse (ca. 60% RH), with gradual weekly reductions in humidity by 10% over 2 weeks.
APA, Harvard, Vancouver, ISO, and other styles
40

Wongroung, Sasitorn. "Antifreeze compounds and their effects on plant tissues." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312570.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Blakemore, Philip Alexander. "Optimisation of steam reconditioning for regrowth-ash and plantation-grown eucalypt species." Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/2343.

Full text
Abstract:
Thesis (Ph. D.)--University of Sydney, 2008.
Includes graphs and tables. Includes list of publications: p. iv. Title from title screen (viewed May 5, 2008). Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Chemical and Biomolecular Engineering. Includes bibliographical references. Also available in print form.
APA, Harvard, Vancouver, ISO, and other styles
42

Vickovic, Sanja. "Transcriptome-wide analysis in cells and tissues." Doctoral thesis, KTH, Genteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199447.

Full text
Abstract:
High-throughput sequencing has greatly influenced the amount of data produced and biological questions asked and answered. Sequencing approaches have also enabled rapid development of related technological fields such as single-cell and spatially resolved expression profiling. The introductory parts of this thesis give an overview of the basic molecular and technological apparatus needed to analyse the transcriptome in cells and tissues. This is succeeded by a summary of present investigations that report recent advancements in RNA profiling. RNA integrity needs to be preserved for accurate gene expression analysis. A method providing a low-cost alternative for RNA preservation was reported. Namely, a low concentration of buffered formaldehyde was used for fixation of human cell lines and peripheral blood cells (Paper I). The results from bulk RNA sequencing confirmed gene expression was not negatively impacted with the preservation procedure (r2>0.88) and that long-term storage of such samples was possible (r2=0.95). However, it is important to note that a small population of cells overexpressing a limited amount of genes can skew bulk gene expression analyses making them sufficient only in carefully designed studies. Therefore, gene expression should be investigated at the single cell resolution when possible. A method for high-throughput single cell expression profiling termed microarrayed single-cell sequencing was developed (Paper II). The method incorporated fluorescence-activated cell sorting, sample deposition and profiling of thousands of barcoded single cells in one reaction. After sample attachment to a barcoded array, a high-resolution image was taken which linked the position of each array barcode sequence to each individual deposited cell. The cDNA synthesis efficiency was estimated at 17.3% while detecting 27,427 transcripts per cell on average. Additionally, spatially resolved analysis is important in cell differentiation, organ development and pathological changes. Current methods are limited in terms of throughput, cost and time. For that reason, the spatial transcriptomics method was developed (Paper III). Here, the barcoded microarray was used to obtain spatially resolved expression profiles from tissue sections using the same imaging principle. The mouse olfactory bulb was profiled on a whole-transcriptome scale and the results showed that the expression correlated well (r2=0.94-0.97) as compared to bulk RNA sequencing. The method was 6.9% efficient, reported signal diffusion at ~2 μm and accurately deconvoluted layer-specific transcripts in an unbiased manner. Lastly, the spatial transcriptomics concept was applied to profile human breast tumours in three dimensions (Paper IV). Unbiased clustering revealed previously un-annotated regions and classified them as parts of the immune system, providing a detailed view into complex interactions and crosstalk in the whole tissue volume. Spatial tumour classification divulged that certain parts of the tumour clearly classified as other subtypes as compared to bulk analysis providing useful data for current practice diagnostics. The last part of the thesis discusses a look towards the future, how the presented methods could be used, improved upon or combined in translational research.

QC 20170109

APA, Harvard, Vancouver, ISO, and other styles
43

GRASSI, SCALVINI FRANCESCA. "PROTEOMIC ANALYSIS OF NEURONAL CELLS AND TISSUES." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/690027.

Full text
Abstract:
Abstract During my three years of PhD I had the opportunity to work with different biological samples analyzing the content and type of proteins through the proteomic approach. In the thesis I describe how a proteomic approach could be useful to analyze different aspect connected to central nervous system. Indeed, the present work is divided in three different parts but the fil rouge is represented by the same analysis technique, a shotgun label-free proteomic approach, for the identification and quantification of expressed proteins, applied to different neuronal cells and tissues: 1) PC12 cells, a wellstudied neuronal cell model due to the ability to easily differentiate into neuron-like cells, 2) Neuro2a cells, another neuronal cellular model very well studied, and 3) the brain of Zebrafish. It is a poikilotherm and eurytherm and therefore it has a wide thermal tolerance, from 6°C to 38°C, temperatures between 24 and 30°C are more suitable for its development, growth and reproduction. Moreover, Danio rerio represents a good animal model for different type of research because it has a generation time of 3-4 months, its maintenance is cheaper than that for rats and mice and required little space. Starting with the first project the proteomic approach is used to dissect at the proteome level similarities and differences between the biochemically and mechanotransductively promoted neuronal differentiation of PC12 cells growth on cluster-assembled zirconia surface with 15nm of roughness, polylysine coated glass in the presence (NGF) or absence (PLL) of NGF. This work lays a substantial cell biological foundation for the intelligent design of substrates for cell culturing based on nanostructured surfaces produced by cluster assembling that mimic more closely physiological 3D extracellular microenvironmental features. Our data suggest that the nanoscale information provided by these surfaces could have a strong potential in favoring neurogenic processes by mechanotransductive processes. The results obtained on zirconia nanostructure can be the fundamental starting point to further characterize the neuronal differentiation process in adequate primary and stem cell systems for regenerative medicine approach. The second part of this work has the aim to understand how the activation of the TrkA pathway is able to trigger biochemical signaling, like ERK1/2, leading to cell differentiation when GM1 oligosaccharide, II3Neu5Ac-Gg4 (OligoGM1), which interacts with NGF receptor TrkA, is administered to cultured murine Neuro2a neuroblastoma cells. The results of our work confirm and reinforce the idea that the molecular mechanisms underlying the GM1 neurotrophic and neuroprotective effects depend on its oligosaccharide chain, suggesting the activation of a positive signaling starting at plasma membrane level. The third part of this thesis regards the determination of the effect of ambient temperature on the molecular mechanism and the behavioural responses in Danio rerio. This project can be framed in a quite interesting area of research, important because global warming occurring in our planet is, especially nowadays, an urgent problem amplified by the anthropic action, the release of CO2 and other greenhouse gases. The huge temperature increase causes climate changes that can deeply alter the habitat of the species, leading to substantial environmental changes possibly impairing the prosecution of the species. We applied for the first time a shotgun proteomic approach to analyze the effect of acclimatization on zebrafish brain proteome and to correlate the results at the protein level with the behavioural tests. As stated above, the shotgun proteomic approach adopted is a powerful analytical method for characterizing the complex proteomes of various types of biological specimens. To characterize the protein component of our sample, we have adopted a quantitative label free shotgun proteomic approach. In recent years, non-gel-based, shotgun proteomic technique has emerged as powerful tool for studying large scale differential protein expression [1]. This method allows to examine the impact of different conditions by achieving the simultaneous identification of thousands of proteins and their quantification in each sample. It does not require a previous purification of the sample, but identifies proteins from tandem mass spectra (MS/MS) of their proteolytic peptides, which are separated by liquid chromatography (LC) [2]. In particular, the identification of the proteins from the MS/MS data was achieved using a database search by MaxQuant which compares acquired mass spectra to a database of known sequences to identify the proteins. 1. Zhu W, Smith JW, Huang CM. Mass spectrometry-based label-free quantitative proteomics. J Biomed Biotechnol. 2010;2010:840518. doi: 10.1155/2010/840518. Epub 2009 Nov 10 2. Washburn MP. Driving biochemical discovery with quantitative proteomics. Trends Biochem Sci. 2011 Mar;36(3):170-7. doi: 10.1016/j.tibs.2010.09.001. Epub 2010 Sep 27
APA, Harvard, Vancouver, ISO, and other styles
44

De, Both Michiel Theodoor Jan. "Gene transfer by electroporation in plant protoplasts and tissues." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46278.

Full text
APA, Harvard, Vancouver, ISO, and other styles
45

Woods, Clare A. "Respiratory carbon loss in plant tissues under environmental stress." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:829338ba-7c5a-41b8-9cdd-ead4646e161e.

Full text
Abstract:
Crop productivity is a balance between carbon gain by photosynthetic assimilation of CO2 and the release of fixed carbon as CO2 via respiration. Respiration is the process by which carbohydrates are oxidised to produce ATP to fuel biochemical reactions, whilst simultaneously releasing CO2 as a by-product; therefore, increased demand for ATP or decreased efficiency of ATP production by uncoupling of the mitochondrial electron transport chain results in greater CO2 production. ATP produced by respiration is either used to support processes involved in growth or to power cell maintenance processes, such as macromolecule turnover or maintenance of membrane ion gradients. Respiration increases when plants are exposed to high temperatures; a factor that will become increasingly important as we try to maximise food production as the global climate changes. However, it is unknown if increased respiration at high temperature is necessary to provide energy to support growth, is a consequence of increased ATP consumption for maintenance processes or is due to increased mitochondrial uncoupling at high temperature. Flux measurements showed that CO2 production by excised Arabidopsis thaliana roots increases with temperature up to 37°C. Although growth also increased up to 37°C resulting in increased respiration associated with growth processes, the majority of overall CO2 production at high temperatures could be accounted for by non-growth respiration. An analysis of ATP-consuming processes demonstrated that protein turnover and maintenance of ion gradients collectively account for the majority of maintenance respiration, but that ATP consumption for the maintenance of ion gradients is quantitatively more important than protein turnover at high temperature. Furthermore, a decrease in in vivo P/O ratio at high temperature was demonstrated; the results presented suggest that this is most likely due to increased basal proton leak across the inner mitochondrial membrane. It can be concluded that increased CO2 production at high temperature results from a combination of increased ATP consumption for the maintenance of ion gradients and a decrease in coupling of the mitochondrial electron transport chain through a common mechanism of increased membrane fluidity and ion leak.
APA, Harvard, Vancouver, ISO, and other styles
46

Rahman, Mahbubur, Uday K. Divi, Qing Liu, Xue-Rong Ahou, Surinder Singh, and Aruna Kilaru. "Oil-Rich Nonseed Tissues for Enhancing Plant Oil Production." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/4746.

Full text
Abstract:
Plants are being engineered for enhanced ethanol production; however, challenges remain in meeting the demand for bioenergy that is expected to double by 2030. Therefore, targeting carbon accumulation in the form of energy-dense oils in nonseed biomass is considered a superior alternative for bioenergy production. Although oils in the form of triacylglycerols (TAGs) are typically stored in seed tissues, various nonseed tissues such as mesocarp, tubers, stems and leaves also serve as storage tissues for TAG accumulation in plants. Moreover, the biomass of these tissues is generally far greater than seed biomass. In order to increase oil content in nonseed biomass for bioenergy and nutritional purposes, it is important to understand how such plants naturally accumulate TAG in nonseed tissues. Several molecular approaches, including transcriptomics, have been undertaken to elucidate the metabolic and regulatory mechanisms of carbon partitioning in oil-rich nonseed tissues. Such studies are expected to generate important transgenic tools that can be used to alter fatty acid metabolism and engineer plants to produce oil-rich biomass successfully. This review focuses on the potential of different oil-rich nonseed tissues and the strategies developed for enhancing oil biomass.
APA, Harvard, Vancouver, ISO, and other styles
47

Kilaru, Aruna. "Conserved Regulation of Oil Biosynthesis in Diverse Plant Tissues." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/4760.

Full text
APA, Harvard, Vancouver, ISO, and other styles
48

Lunn, John Edward. "The control of sucrose synthesis in non-photosynthetic tissues." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304460.

Full text
APA, Harvard, Vancouver, ISO, and other styles
49

Stamou, Efthimia. "Aeroporation of plant cells." Thesis, University of Essex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409975.

Full text
APA, Harvard, Vancouver, ISO, and other styles
50

Yamagishi, Masumi. "Genetic evaluation of cell and tissue culture-derived rice plants." Kyoto University, 1997. http://hdl.handle.net/2433/202414.

Full text
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography