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Expressed sequence tags and functional characterization of fruiting genes during fruit body development of edible mushroom Lentinula edodes.January 2000 (has links)
by Ng Tak Pan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 151-168). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Abbreviations --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xiii / Chapter Chapter One --- Literature Review / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Nutraceutical and Medicinal Properties of L. edodes --- p.4 / Chapter 1.2.1 --- Nutritional value --- p.4 / Chapter 1.2.2 --- Hypocholesterolaemic Effect --- p.5 / Chapter 1.2.3 --- Anti-tumor Effect --- p.5 / Chapter 1.2.4 --- Anti-viral Effect --- p.6 / Chapter 1.2.5 --- Immunopotentiating Effect --- p.6 / Chapter 1.3 --- Life cycle of L. edodes --- p.7 / Chapter 1.4 --- Environmental factors affecting mycelial growth and fruit body --- p.11 / Chapter 1.4.1 --- Nutrient requirement --- p.11 / Chapter 1.4.2 --- Physical and chemical factors --- p.12 / Chapter 1.5 --- Molecular studies on mushroom development --- p.15 / Chapter 1.5.1 --- Mating-type genes --- p.15 / Chapter 1.5.2 --- Hydrophobins --- p.19 / Chapter 1.5.3 --- Fruiting regulatory genes --- p.23 / Chapter 1.5.4 --- Molecular studies on fruit body development of I. edodes --- p.24 / Chapter 1.5.4.1 --- Identification of L. edodes genes --- p.24 / Chapter 1.5.4.2 --- Functional characterization of L. edodes genes --- p.27 / Chapter 1.5.4.3 --- Transformation in L. edodes --- p.28 / Chapter Chapter Two --- Expressed Sequence Tags (ESTs) of L. edodes / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Materials and Methods --- p.33 / Chapter 2.2.1 --- Generation of expressed sequence tag --- p.33 / Chapter 2.2.1.1 --- Mushroom cultivation and RNA extraction --- p.33 / Chapter 2.2.1.2 --- Construction of primordium cDNA library --- p.34 / Chapter 2.2.1.3 --- Mass excision of pBK-CMV plasmid --- p.34 / Chapter 2.2.1.4 --- Random screening of mass excised cDNA clone --- p.38 / Chapter 2.2.1.5 --- Isolation of recombinant plasmid --- p.38 / Chapter 2.2.1.6 --- Generation of 3´ة end partially sequence --- p.39 / Chapter 2.2.1.7 --- Sequence analysis --- p.40 / Chapter 2.2.2 --- Reverse dot-blot Hybridization --- p.40 / Chapter 2.2.2.1 --- PCR amplification of cDNA clone --- p.40 / Chapter 2.2.2.2 --- Membrane preparation --- p.40 / Chapter 2.2.2.3 --- cDNA probe preparation --- p.41 / Chapter 2.2.2.4 --- Hybridization --- p.42 / Chapter 2.2.2.5 --- Stringent washing and autoradiography --- p.43 / Chapter 2.3 --- Results --- p.44 / Chapter 2.3.1 --- Construction of primordium cDNA library --- p.44 / Chapter 2.3.2 --- Screening of recombinant clone --- p.44 / Chapter 2.3.3 --- Isolation and reconfirmation of recombinant plasmid --- p.46 / Chapter 2.3.4 --- Generation of EST --- p.47 / Chapter 2.3.5 --- EST identity --- p.47 / Chapter 2.3.6 --- Reverse dot-blot hybridization --- p.56 / Chapter 2.3.7 --- Analysis of hybridization signal --- p.60 / Chapter 2.4 --- Discussion --- p.71 / Chapter Chapter Three --- Sequence Analysis and Transcriptional Profiling of Genes Encoding GTP-binding Proteins / Chapter 3.1 --- Introduction --- p.78 / Chapter 3.2 --- Materials and Methods --- p.82 / Chapter 3.2.1 --- Sequence manipulation --- p.82 / Chapter 3.2.2 --- Northern blot hybridization --- p.82 / Chapter 3.2.2.1 --- RNA fragmentation by formaldehyde gel electrophoresis --- p.82 / Chapter 3.2.2.2 --- RNA fixation by capillary method --- p.83 / Chapter 3.2.2.3 --- Probe preparation --- p.84 / Chapter 3.2.2.4 --- Hybridization --- p.85 / Chapter 3.2.2.5 --- Stringent washing and autoradiography --- p.85 / Chapter 3.2.3 --- Real-Time SYBR Green RT-PCR --- p.85 / Chapter 3.2.3.1 --- Primer design --- p.85 / Chapter 3.2.3.2 --- RT-PCR reaction --- p.86 / Chapter 3.3 --- Results --- p.88 / Chapter 3.3.1 --- Sequence manipulation --- p.88 / Chapter 3.3.2 --- Transcriptional analysis --- p.103 / Chapter 3.4 --- Discussion --- p.108 / Chapter 3.4.1 --- Heterotrimeric G proteins --- p.108 / Chapter 3.4.2 --- Ras-related protein Rab7 --- p.112 / Chapter 3.4.3 --- Developmentally regulated GTP-binding protein --- p.113 / Chapter Chapter Four --- Yeast Complementation and Over-expression tests of Le.Gβ1 and Le.Gγ1 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and Methods --- p.120 / Chapter 4.2.1 --- "Yeast strains, media and yeast vectors" --- p.120 / Chapter 4.2.2 --- Primer design --- p.121 / Chapter 4.2.3 --- RT-PCR Amplification of Le.Gβ1 and Le.Gγ1 --- p.121 / Chapter 4.2.4 --- Purification of PCR products --- p.122 / Chapter 4.2.5 --- Enzymatic digestion and purification --- p.122 / Chapter 4.2.6 --- Ligation and E. coli transformation --- p.122 / Chapter 4.2.7 --- PCR screening of E. coli transformants --- p.124 / Chapter 4.2.8 --- Plasmids extraction --- p.124 / Chapter 4.2.9 --- Yeast transformation --- p.124 / Chapter 4.2.10 --- Mating test --- p.125 / Chapter 4.3 --- Results --- p.129 / Chapter 4.3.1 --- Cloning of Le.Gβ1 and Le.Gγ1 --- p.129 / Chapter 4.3.2 --- Yeast transformation --- p.129 / Chapter 4.3.3 --- Mating test --- p.130 / Chapter 4.4 --- Discussion --- p.141 / Chapter Chapter Five --- General Discussion --- p.144 / References --- p.151
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Identificação e caracterização de seqüências expressas (EST) na musculatura peitoral de frangos de corte. / Identification and characterization of expressed sequence tags (EST) in broilers breast muscle.Alves, Helena Javiel 23 November 2004 (has links)
A produção de aves no Brasil vem crescendo na ordem de 10% a cada ano, o que se explica pela atualização constante da tecnologia do setor (http://www.abef.com.br). Sendo a carne de frango a fonte de proteína animal mais barata e acessível ao consumidor, há necessidade de se produzir cada vez mais animais com maior acúmulo de massa muscular. Para isso, o entendimento dos mecanismos celulares e moleculares envolvidos na formação da musculatura esquelética é de extrema relevância. Os fatores miogênicos, genes responsáveis pela determinação e diferenciação de células musculares, foram clonados e progressos significativos foram desenvolvidos quanto ao controle da expressão dos mesmos. A utilização da técnica de seqüenciamento de DNA possibilita a identificação e caracterização de novos genes envolvidos na complexa rede de fatores que regulam a formação da musculatura esquelética em aves. Neste estudo, foram construídas duas bibliotecas de cDNA (fase embrionária e pós-eclosão) de músculo peitoral de uma linhagem de corte (TT) e uma biblioteca da fase embrionária de uma linhagem de postura (CC). A análise das seqüências EST (Expressed Sequence Tags) foi utilizada para identificar possíveis novos genes envolvidos no processo de formação da musculatura esquelética. As seqüências EST identificadas possibilitaram a construção de um banco com 6247 ESTs da musculatura peitoral das linhagens de corte e postura nas duas fases de desenvolvimento. Com o intuito de estabelecer uma relação entre o perfil de expressão dos fatores miogênicos: MyoD, MRF4 e miogenina; e dos genes Pax-3 e miostatina e a formação e maturação das fibras musculares, foi utilizada a técnica de PCR em tempo real. Em geral, a expressão dos fatores miogênicos foi maior na linhagem de corte em relação à de postura nas idades estudadas. Este estudo deverá contribuir para as áreas celular e molecular de desenvolvimento, além de fornecer recursos úteis aos programas de melhoramento genético de aves que visam obter animais com maior acúmulo de massa muscular. / Brazilians chicken production is increasing annually around 10%, which can be explained by the current technology applied to this sector (http://www.abef.com.br). Being chickens meat the cheapest animal protein source for consumers, there is a need to produce even more animals with increased muscular mass. For this purpose, understanding the molecular and cellular mechanisms involved with the skeletal muscle development is of great relevance. The myogenic factors, genes responsible for the determination and differentiation of muscle cells, were cloned and significant progress was made on the control of their expression. The use of DNA sequencing technique allows the identification and characterization of new genes involved in the complex chain of factors signalling systems that regulates the expression of avian skeletal muscles. In this study, two cDNA libraries (embryonic and post-hatching phases) were constructed from the breast muscle of a chicken broiler line (TT) and one library, from the embryonic phase, from a chicken layer line (CC). The EST (Expressed Sequencing Tags) analysis was used to identify probable new genes involved in the skeletal muscle development. The identified ESTs were used to generate a database containing 6247 breast muscle ESTs from two chicken lines in two development phases. Real time PCR was employed with the aim of establishing a relationship among the expression profile of myogenic factors (MyoD, MFR4, and myogenin), Pax-3 and myostatin genes with the formation and maturation of muscle fibers. In general, the expression of myogenic factors was greater in the broiler than in the layer chicken line in the phases under study. These results should contribute to other cellular and molecular development studies besides providing useful resources for chicken breeding programs whose objective is the deposition of skeletal muscle mass.
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Design of high performance RFID systems for metallic item identification.Ng, Mun Leng January 2008 (has links)
Although the origins of Radio Frequency Identification (RFID) technology can be traced back for many years, it is only recently that RFID has experienced rapid growth. That growth is mainly due to the increasing application of this technology in various supply chains. The widening of the implementation of RFID technology in supply chains has posed many challenges and one of the biggest is the degradation of the RFID system performance when tagging metallic objects, or when the RFID system operates in a metallic environment. This thesis focuses on tackling the issue of having metallic objects in an Ultra High Frequency (UHF) RFID system. The work presented in this thesis contributes to the research on UHF RFID systems involving metallic objects in several ways: (a) the development of novel RFID tags that range from a simple tag for general applications to tags suitable for metallic object identification; (b) the tag designs target the criteria of minimal tag size and cost to embrace the vision of item level tagging; and (c) the analysis of the performance (through theoretical predictions and practical measurements) of an RFID tag near metallic structures of various shapes and sizes. The early part of this thesis provides a brief introduction to RFID and reviews the background information related to metallic object identification for UHF RFID systems. The process of designing a basic tag, and additional information and work done related to the process, are outlined in the early part of this thesis. As part of this fundamental research process, and before proceeding to the designing of tags specifically for metallic objects, a small and low cost RFID tag for general applications was developed. Details of the design of this tag, with the application of this tag for animal identification, are presented. In the later parts of the work, different tag design approaches were explored and this has generated three rather different RFID tags suitable for attaching to metallic objects. The aim of this research is not just to design tags for metallic objects but also to tackle the constraints of having tags that are small in size, cost effective and suited in size to some familiar objects. Hence, in the later part of this research, the work took a step further where one of the three tags designed for metallic objects addressed the challenge of identifying individual small metallic beverage cans. RFID involves tagging of different types of objects and a tag may be required to be located in a depression of a metallic object. In the final part of this research, the read range performance of one of the RFID tags designed for metallic objects was analysed when the tag was located in metallic depressions of various shapes and sizes. The analysis was performed from a combination of theoretical calculation and simulation perspectives, and also through practical real-life measurements. Metallic objects are very common around us. Their presence is unavoidable and so to identify them, having the appropriate RFID tags suitable for operation on metallic surfaces is essential. Frequently the tags must be small in size and low in cost to allow identification at item level of individual small metallic objects. Understanding and being aware of the potential effects of metallic structures of various shapes and sizes on the tag performance is thus important. The research in this thesis into all the above can bring the industry further towards full deployment of RFID down to item level tagging. / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2008
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Conception d'antennes de tags RFID UHF, application a la réalisation par jet de matière.Ghiotto, Anthony 26 November 2008 (has links) (PDF)
L'identification par radiofréquence constitue une technologie émergente et très prometteuse pour l'identification des biens et des personnes : automatisation des opérations manuelles, rapidité, informations précises...<br />Il existe plusieurs technologies RFID. Dans cette thèse, nous nous intéressons à la technologie UHF passive et plus particulièrement à la conception, caractérisation et fabrication des antennes de tags RFID. En 2007, il s'est vendu plus de 1,7 milliard de tags RFID. En vue de réduire le coût de ces derniers, nous abordons leur fabrication par une technique très prometteuse qui pourrait révolutionner l'électronique, le jet d'encre. Ces travaux s'appuient sur des simulations électromagnétiques et des mesures, et considèrent différents types d'antennes RFID.
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Molecular and Genetic Strategies to Enhance Functional Expression of Recombinant Protein in Escherichia coliNarayanan, Niju January 2009 (has links)
The versatile Escherichia coli facilitates protein expression with relative simplicity, high cell density on inexpensive substrates, well known genetics, variety of expression vectors, mutant strains, co-overexpression technology, extracytoplasmic secretion systems, and recombinant protein fusion partners. Although, the protocol is rather simple for soluble proteins, heterologous protein expression is frequently encountered by major technical limitations including inefficient translation, formation of insoluble inclusion bodies, lack of posttranslational modification mechanisms, degradation by host proteases, and impaired cell physiology due to host/protein toxicity, in achieving functional expression of stable, soluble, and bioactive protein.. In this thesis, model protein expression systems are used to address the technical issues for enhancing recombinant protein expression in E. coli.
When yellow fluorescence protein (YFP) was displayed on E. coli cell surface, the integrity of the cell envelope was compromised and cell physiology was severely impaired, resulting in poor display performance, which was restored by the coexpression of Skp, a periplasmic chaperone. On the basis of monitoring the promoter activities of degP, rpoH, and cpxP under various culture conditions, it was demonstrated that the cell-surface display induced the σE extracytoplasmic stress response, and PdegP::lacZ was proposed to be a suitable “sensor” for monitoring extracytoplasmic stress.
Intracellular proteolysis has been recognized as one of the key factors limiting recombinant protein production, particularly for eukaryotic proteins heterologously expressed in the prokaryotic expression systems of E. coli. Two amino acids, Leu149 and Val223, were identified as proteolytically sensitive when Pseudozyma antarctica lipase (PalB) was heterologously expressed in Escherichia coli. The functional expression was enhanced using the double mutant for cultivation. However, the recombinant protein production was still limited by PalB misfolding, which was resolved by DsbA coexpression. The study offers an alternative genetic strategy in molecular manipulation to enhance recombinant protein production in E. coli.
To overcome the technical limitations of protein misfolding, ineffective disulfide bond formation, and protein instability associated with intracellular proteolysis in the functional expression of recombinant Pseudozyma antarctica lipase B (PalB) in Escherichia coli, an alternative approach was explored by extracellular secretion of PalB via two Sec-independent secretion systems, i.e. the α-hemolysin (Type I) and the modified flagellar (Type III) secretion systems, which can export proteins of interest from the cytoplasm directly to the exterior of the cell. Bioactive PalB was expressed and secreted extracellularly either as HlyA fusion (i.e. PalB-HlyA via Type I system) or an intact protein (via Type III system) with minimum impact on cell physiology. However, the secretion intermediates in the intracellular fraction of culture samples were non-bioactive even though they were soluble, suggesting that the extracellular secretion did mediate the development of PalB activity. PalB secretion via Type I system was fast with higher specific PalB activities but poor cell growth. On the other hand, the secretion via Type III system was slow with lower specific PalB activities but effective cell growth.
Functional expression of lipase from Burkholderia sp. C20 (Lip) in various cellular compartments of Escherichia coli was explored. The poor expression in the cytoplasm was improved by several strategies, including coexpression of the cytoplasmic chaperone GroEL/ES, using a mutant E. coli host strain with an oxidative cytoplasm, and protein fusion technology. Fusing Lip with the N-terminal peptide tags of T7PK, DsbA, and DsbC was effective in boosting the solubility and biological activity. Non-fused Lip or Lip fusions heterologously expressed in the periplasm formed insoluble aggregates with a minimum activity. Biologically active and intact Lip was obtained upon the secretion into the extracellular medium using the native signal peptide and the expression performance was further improved by coexpression of the periplasmic chaperon Skp. The extracellular expression was even more effective when Lip was secreted as a Lip-HlyA fusion via the α-hemolysin transporter. Finally, Lip could be functionally displayed on the E. coli cell surface when fused with the carrier EstA.
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Molecular and Genetic Strategies to Enhance Functional Expression of Recombinant Protein in Escherichia coliNarayanan, Niju January 2009 (has links)
The versatile Escherichia coli facilitates protein expression with relative simplicity, high cell density on inexpensive substrates, well known genetics, variety of expression vectors, mutant strains, co-overexpression technology, extracytoplasmic secretion systems, and recombinant protein fusion partners. Although, the protocol is rather simple for soluble proteins, heterologous protein expression is frequently encountered by major technical limitations including inefficient translation, formation of insoluble inclusion bodies, lack of posttranslational modification mechanisms, degradation by host proteases, and impaired cell physiology due to host/protein toxicity, in achieving functional expression of stable, soluble, and bioactive protein.. In this thesis, model protein expression systems are used to address the technical issues for enhancing recombinant protein expression in E. coli.
When yellow fluorescence protein (YFP) was displayed on E. coli cell surface, the integrity of the cell envelope was compromised and cell physiology was severely impaired, resulting in poor display performance, which was restored by the coexpression of Skp, a periplasmic chaperone. On the basis of monitoring the promoter activities of degP, rpoH, and cpxP under various culture conditions, it was demonstrated that the cell-surface display induced the σE extracytoplasmic stress response, and PdegP::lacZ was proposed to be a suitable “sensor” for monitoring extracytoplasmic stress.
Intracellular proteolysis has been recognized as one of the key factors limiting recombinant protein production, particularly for eukaryotic proteins heterologously expressed in the prokaryotic expression systems of E. coli. Two amino acids, Leu149 and Val223, were identified as proteolytically sensitive when Pseudozyma antarctica lipase (PalB) was heterologously expressed in Escherichia coli. The functional expression was enhanced using the double mutant for cultivation. However, the recombinant protein production was still limited by PalB misfolding, which was resolved by DsbA coexpression. The study offers an alternative genetic strategy in molecular manipulation to enhance recombinant protein production in E. coli.
To overcome the technical limitations of protein misfolding, ineffective disulfide bond formation, and protein instability associated with intracellular proteolysis in the functional expression of recombinant Pseudozyma antarctica lipase B (PalB) in Escherichia coli, an alternative approach was explored by extracellular secretion of PalB via two Sec-independent secretion systems, i.e. the α-hemolysin (Type I) and the modified flagellar (Type III) secretion systems, which can export proteins of interest from the cytoplasm directly to the exterior of the cell. Bioactive PalB was expressed and secreted extracellularly either as HlyA fusion (i.e. PalB-HlyA via Type I system) or an intact protein (via Type III system) with minimum impact on cell physiology. However, the secretion intermediates in the intracellular fraction of culture samples were non-bioactive even though they were soluble, suggesting that the extracellular secretion did mediate the development of PalB activity. PalB secretion via Type I system was fast with higher specific PalB activities but poor cell growth. On the other hand, the secretion via Type III system was slow with lower specific PalB activities but effective cell growth.
Functional expression of lipase from Burkholderia sp. C20 (Lip) in various cellular compartments of Escherichia coli was explored. The poor expression in the cytoplasm was improved by several strategies, including coexpression of the cytoplasmic chaperone GroEL/ES, using a mutant E. coli host strain with an oxidative cytoplasm, and protein fusion technology. Fusing Lip with the N-terminal peptide tags of T7PK, DsbA, and DsbC was effective in boosting the solubility and biological activity. Non-fused Lip or Lip fusions heterologously expressed in the periplasm formed insoluble aggregates with a minimum activity. Biologically active and intact Lip was obtained upon the secretion into the extracellular medium using the native signal peptide and the expression performance was further improved by coexpression of the periplasmic chaperon Skp. The extracellular expression was even more effective when Lip was secreted as a Lip-HlyA fusion via the α-hemolysin transporter. Finally, Lip could be functionally displayed on the E. coli cell surface when fused with the carrier EstA.
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Implementation and Applications of an Anti-Collision Differential-Offset Spread Spectrum RFID SystemRohatgi, Anil 11 August 2006 (has links)
This report documents the design, construction, and implementation of a differential-offset spread spectrum RFID system, to avoid the problem of anti-collision interference from multiple RFID tags. Currently in industry, this problem is handled by establishing a two way communication link between the tags and the interrogator. The proposed system eliminates the need for the excessive hardware use to create this link, and therefore drastically reduces the cost of each tag. Not only is this system cheaper to implement but it is faster, requires less power, and by the nature of the design contains an inherent encryption scheme for the data being transmitted.
Specialized RFID tags were designed and fabricated in order to produce a pseudo random code unique to each tag. The design presented in this document allowed simultaneous interrogation of up to 255 tags within one sensing environment. Once queried, the tags then modulate the incoming signal from the interrogator with their own sequence, and reflect the signal back to the interrogator. What the interrogator then receives is a combination of backscatter from all of the tags within the sensing environment. Specialized software written in Matlab and LabView uses these unique sequences to isolate the data from a desired tag away from the sea of information being transmitted from every tag. Using this system, numerous applications for experiments and measurements can be devised.
One such application this thesis focuses on is the use of this system to simultaneously measure signal strengths from multiple diversity antennas in order to optimize their position and orientation. Currently, the majority of antenna diversity measurements are taken by measuring the signal strength of a given configuration one antenna at a time. By using the anti-collision RFID system proposed above, the signal strength produced by both antennas can be measured and recorded simultaneously to provide a true representation of their combined performance. This measurement can be used to find the optimal configuration for multiple antennas.
This thesis will fully explore the theories and procedures behind creating this system, and will provide the results and analysis of its performance.
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Dissection of defense responses of skl, an ethylene insensitive mutant of Medicago truncatulaPedro, Uribe Mejia 15 November 2004 (has links)
The interactions between Medicago truncatula and Phytophthora medicaginis were examined using skl, a mutant blocked in ethylene perception, and a range of wild accessions of this plant species. P. medicaginis infection of M. truncatula plants resulted in compatible responses, whereas the mutant genotype was found to be hyper-susceptible to the pathogen. Phytophthora reproduction and colonization rates of Medicago tissues supported this conclusion. Infection of skl with different pathogens reinforced this observation. Ethylene production in infected A17 and skl roots showed reduced ethylene evolution in the mutant and suggested that a positive feedback loop, known as autocatalytic ethylene production, amplified the ethylene signal.
To complement the study, expression analyses of defense response genes in this interaction were studied by real time RTPCR of Phytophthora-infected and mock-infected roots. The genes analyzed were PAL, CHS, IFR, ACC oxidase, GST, and PR10. The sequences needed for the analysis were found through the scrutiny of the M. truncatula EST database employing phylogenetics and bio-informatics tools. In A17 all the genes studied were up-regulated, although the specific gene expression patterns differed. The comparison of gene expression between A17 and skl genotypes allowed the differentiation between ethylene-dependent and ethylene-independent responses. Discrete results showed that ACC oxidase homologues were downregulated in the ethylene perception mutant, corroborating the ethylene observations. However, the expression of genes involved in the phenylpropanoid metabolism was increased in skl relative to A17, suggestive of an antagonism between the ethylene perception pathway and the regulation of the phenylpropanoid pathway. This result implied that Medicago phytoalexins accumulate in the disease interaction, but raised questions about their role in resistance to Phytophthora infection.
This study establishes a link between mechanisms that regulate symbiotic infection and the regulation of disease resistance to Oomycete pathogens, especially P. medicaginis. The results served to identify a series of Phytophthora-induced genes, which remain pathogen-responsive even in the absence of a functional ethylene perception pathway. While it is possible that the products of these genes are involved in resistance to P. medicaginis, the present results demonstrate that ethylene perception is required for resistance.
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Religion and social change a sociological study of Seventh-Day Adventism in Kenya /Nyaundi, Nehemiah M. January 1900 (has links)
Previously issued as Thesis (doctoral)--Lund, 1993. / Includes bibliographical references (p. 268-278).
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Design and modelling of passive UHF RFID tags for energy efficient liquid level detection applications : a study of various techniques in the design, modelling, optimisation and deployment of RFID reader and passive UHF RFID tags to achieve effective performance for liquid sensing applicationsAtojoko, Achimugu A. January 2016 (has links)
Sewer and oil pipeline spillage issues have become major causes of pollution in urban and rural areas usually caused by blockages in the water storage and drainage system, and oil spillage of underground oil pipelines. An effective way of avoiding this problem will be by deploying some mechanism to monitor these installations at each point in time and reporting unusual liquid activity to the relevant authorities for prompt action to avoid a flooding or spillage occurrence. This research work presents a low cost energy efficient liquid level monitoring technique using Radio Frequency Identification Technology. Passive UHF RFID tags have been designed, modelled and optimized. A simple rectangular tag, the P-shaped tag and S-shaped tag with UHF band frequency of operation (850-950 MHz) has been designed and modelled. Detailed parametric analysis of the rectangular tag is made and the optimised design results analysed and presented in HFSS and Matlab. The optimised rectangular tag designs are then deployed as level sensors in a gully pot. Identical tags were deployed to detect 4 distinct levels in alternate positions and a few inches in seperation distance within the gully pot height (Low, Mid, High and Ultra high). The radiation characteristic of tag sensors in deployment as modelled on HFSS is observed to show consistent performance with application requirements. An in-manhole chamber antenna for an underground communication system is analysed, designed, deployed and measured. The antenna covers dual-band impedance bandwidths (i.e. 824 to 960 MHz, and 1710 to 2170 MHz). The results show that the antenna prototype exhibits sufficient impedance bandwidth, suitable radiation characteristics, and adequate gains for the required underground wireless sensor applications. Finally, a Linearly Shifted Quadrifilar Helical Antenna (LSQHA) designed using Genetic Algorithm optimisation technique for adoption as an RFID reader antenna is proposed and investigated. The new antenna confirms coverage of the RFID bandwidth 860-960 MHz with acceptable power gain of 13.1 dBi.
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