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1
Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies / Tina Bianco-Miotto". Thesis, Adelaide, S.A, 2002. http://hdl.handle.net/2440/21857.
Testo completoAbstract (sommario):
"May 2002"Includes bibliographical references (leaves 229-251)
xv, 251 leaves : ill. (some col.) ; 30 cm.
Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2003
2
Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies". Adelaide, S.A, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phb578.pdf.
Testo completoAbstract (sommario):
"May 2002" Includes bibliographical references (leaves 229-251) Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
3
Adeleye, Tolulope Abiodun. "A molecular analysis of the immunological response to mycobacterial antigens". Thesis, University College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304066.
Testo completo
4
Davenport, Miles Philip. "Molecular analysis of HLA associations with infectious disease". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297073.
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5
Nath, Deepa. "cDNA sequence analysis of macrophage molecules". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240654.
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6
Shipman, Robert Charles. "The molecular characterization of a common human myelogenous leukemia-associated antigen (CAMAL)". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27530.
Testo completoAbstract (sommario):
Previous studies had demonstrated the presence of the p70 (CAMAL) molecule in human myeloid leukemia cells and the promyelocytic leukemia cell line HL60, but not in equivalent preparations of normal cells (Malcolm et al., 1982, 1984; Shipman et al., 1983; Logan et al., 1984). Subsequent studies demonstrated that the p70 (CAMAL) protein was detectable and expressed in human myeloid leukemia cells and the leukemic cell lines HL60, KG1, K562 and U937. The association of p70 (CAMAL) expression with human myeloid leukemia cells prompted its consideration as a candidate leukemia-associated antigen.
The demonstration, following CAMAL purification and peptide sequencing, that two tryptic peptides (tp27, tp31) displayed significant homology to sequences present in human serum albumin (HSA) and human alpha-1-fetoprotein (AFP), while one tryptic peptide (tp20) displayed unique peptide sequence, suggested that CAMAL might represent a protein that was structurally and functionally related to the albumins. Consequently, a comparative biochemical analysis of CAMAL and HSA was initiated.
The results of the comparative studies demonstrated that although CAMAL and HSA shared conformational antigenic determinants, both proteins were also shown to be distinct molecules by a number of other criteria. The possibility that the CAMAL preparation, used for protein sequencing and comparative studies, was contaminated with HSA was thought likely, in view of the HSA/AFP-related peptide sequences from the CAMAL tryptic peptide sequence analysis. However, other results, particularly the antibody reactivity and ligand binding studies, showed that the CAMAL preparation was not contaminated with HSA. The unique CAMAL tryptic peptide (tp20) sequence supported further the contention that CAMAL was a distinct protein with regions homologous to HSA and AFP.
Further analysis of the CAMAL molecule, through extensive protein sequencing, will be, in all likelihood, the only means by which to establish the degree of relatedness between CAMAL, HSA and AFP.Science, Faculty of
Microbiology and Immunology, Department of
Graduate
7
Purins, Leanne Roslyn. "Molecular characterisation of the transcriptional activator, HLYU, of Vibrio cholerae O1 /". Title page, abstract and table of contents only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09php9857.pdf.
Testo completoAbstract (sommario):
Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Science , Discipline of Microbiology and Immunology, 2005."May, 2004" Includes corrigenda. includes bibliographical references (leaves 118-156).
8
Wright, Andrew. "Molecular analysis of the human antibody response to antigens of Staphylococcus aureus". Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485077.
Testo completoAbstract (sommario):
Staphylococcus aureus is a significant cause of Gram-positive sepsis and infection in the nosocomial environment, and has given rise to the MRSA 'superbug'. The identification of multi-drug resistant strains of S. aureus has advanced the search for new targets for S. aureus prophylaxis or therapy. Such strategies may include the identification of novel S. aureus vaccine candidates, or the production of antibodies to appropriate S. aureus antigens for passive immunization. Previous studies have identified antibodies specific to the major cell wall antigen peptidoglycan as important in the opsonisation of S. aureus, facilitating uptake into phagocytic cells and removal from the host. In agreement with others, our studies have shown antibodies to peptidoglycan and its derivatives are present throughout the population over a wide concentration range and are found in sera from both 'normal' control donors and S. aureus infected individuals. In an attempt to dissect the antibody response to peptidoglycan at the molecular level we have created recombinant human single-chain antibody libraries from the genetic material of such donors, and have screened them for the presence of peptidoglycan specific antibodies. Despite extensive analysis and optimisation of'the library construction and screening process, we were unable to isolate such antibodies from our libraries. However, analysis of a large 'singlepot' synthetic library of antibody variable region genes did lead to the retrieval of two antibodies specific for cellosyl-digested S. aureus peptidoglycan. These antibodies were characterised with respect to antigen binding sensitivity and specificity. This study has also focused on the immune response to CHIPS (the chemotaxis inhibitory protein of Staphylococcus aureus), a recently identified virulence determinant of S. aureus capable ofinhibiting the recruitment ofleukocytes to the site ofbacterial invasion. We have demonstrated the presence of antibodies to CHIPS throughout the population of sera examined. Using a model cell system, we have also identified a role for a high level of anti-CHIPS antibodies in either the inhibition or enhancement of bacterial pathogenesis by modulating binding of CHIPS to the C5a receptor, CD88.
9
Guy, Rebecca Ann. "Giardia lamblia : an analysis of trophozoite antigens using monoclonal antibodies". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55696.
Testo completo
10
Daniels, Craig. "Characterisation of proteins involved in Shigella flexneri O-antigen biosynthesis". Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd186.pdf.
Testo completoAbstract (sommario):
Corrigenda pasted onto back end-papers. Bibliography: leaves 163-182. Analyses the proteins involved in Shigella flexneri O-antigen biosynthesis at the molecular level in order to gain a more concise understanding of the biosynthesis machinery and how it functions.
11
Ramly, Nur Zazarina. "Molecular analysis on the superfamily of surface antigens from the apicomplexan parasite Eimeria tenella". Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577790.
Testo completoAbstract (sommario):
The work in this thesis has been involved with molecular and structural analysis on the superfamily of surface antigens from the apicomplexan parasite Eimeria ten ella, which causes coccidiosis in chickens. Infection by Eimeria is thought to involve a role for a superfamily of more than 60 cysteine-rich surface antigens (SAGs) in host-parasite interactions. These cysteine-rich SAGs can be divided into two families each with two clusters (A and Bf C and D) within which considerable sequence similarity can be seen. A representative member of the family, SAG 19 (cluster A), has been over-expressed in E. coli, purified and crystallised by the hanging-drop method of vapour diffusion using ammonium sulphate as the precipitant. Crystals of SAG 19 diffract to beyond 1.32 A resolution and belong to space group 14 with unit cell dimensions a = b = 108.1 A, c = 37.42 A with a single subunit in the asymmetric unit.
12
Gadd, Stephen J. "Analysis of acute mycloid leukaemia cell surface antigens with monoclonal antibodies". Title page, contents and abstract only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phg123.pdf.
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13
Jaworski, Deborah Carol. "Molecular aspects of early-expressed ixodid tick salivary gland antigens with emphasis on host response to tick feeding /". The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487694702782423.
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14
Mavris, Maria. "Bacteriophage SfII mediated serotype conversion in Shigella flexneri /". Title page, abstract and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm4608.pdf.
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15
彭志明 e Chi-ming Pang. "Molecular analysis of the dehalogenase IVa of Burkholderia cepacia MBA4". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31240872.
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Macpherson, Debbie Freda. "Characterization of the rfb region of Shigella flexneri /". Title page, abstract and contents only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phm172.pdf.
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17
黃鳳如 e Fung-yu Huang. "Molecular and cytogenetic analysis of cervical and vulvar cancer". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B26662188.
Testo completo
18
Alm, Richard A. "Molecular characterization of the haemolysin determinant of Vibrio cholerae O1 /". Title page, contents and abstract only, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09pha444.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1990.Includes an appendix of author's previously published papers. Includes bibliographical references (leaves 123-160).
19
Wang, Yue, e 王悦. "Molecular analysis of mitochondrial DNA alterations in endometrial carcinomas". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32059127.
Testo completo
20
Champion-Suntharalingam, K. M. "Aspects of molecular analysis in myeloproliferative disorders and myelodysplastic syndromes". Thesis, Anglia Ruskin University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342919.
Testo completo
21
Bruiners, Natalie. "Molecular genetic analysis of preterm labour". Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/17741.
Testo completoAbstract (sommario):
Thesis (MSc)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: The World Health Organisation (WHO) has defined preterm labour as the onset of labour before 37 completed weeks of gestation with an incidence ranging between 5-10%. Although patient care has improved, the rate of preterm birth has slowly been increasing and currently impacts significantly on maternal and fetal mortality and morbidity. The complex condition of preterm labour involves multiple etiologies and risk factors, which complicates the search for candidate markers and / or biomarkers. The aim of this prospective study was to investigate potential genetic associations with preterm labour. The study cohort consisted of consecutive first-time booking, low-risk primigravid pregnant women from a restricted geographical region. The study cohort comprised 421 [306 Coloured and 115 Black] pregnant women presenting at the Paarl Hospital Obstetric clinic. Subsequently, DNA was extracted from whole blood and investigated for a range of known polymorphisms in pro-inflammatory and anti-inflammatory cytokines, as well as the novel LGALS13 gene, for potential variants that may impact on pregnancy outcome. Screening techniques involve combinations of allele-specific PCR amplification, Multiphor SSCP/HD analysis, restriction enzyme analyses and DNA sequencing. A significant association was demonstrated between the IL-1RN*2-allele and adverse pregnancy outcome, mainly in the preterm labour and hypertension group. The presence TNFα-308 A-allele was associated with overall adverse pregnancy outcome and preterm labour. In addition to this, a novel IL-1RN allele was identified in the control group. Mutation screening and subsequent statistical methods revealed an association between a novel LGALS13 exonic variant, 221delT, and preterm labour in Coloured women. Two previouslydocumented intronic variants (IVS2-22A/G and IVS3+72T/A) demonstrated linkage disequilibrium, signifying evolutionary conservation of exon three. Additionally, two novel intronic variants, IVS2-36 G/A and IVS2-15 G/A, demonstrated no association with adverse pregnancy outcome. In this study we identified rare novel exonic variants; two non-synonymous variants in exon three (M44V, [N=2] and K87R, [N=1]) and a silent variant in exon four (P117P, [N=1]) - all identified in individuals from the control cohort. Within coding exon three, an interesting variant [“hotspot”] was identified, which represents six polymorphic bases within an 11bp stretch. No associations were demonstrated with these variants and pregnancy outcome. Furthermore, a previously documented 5' “‘promoter” variant, -98 A/C, was identified and demonstrated no association with adverse pregnancy outcome. However, subdivision of lateonset pre-eclamptic cases revealed a significant association with the A-allele and late-onset preeclampsia. Genotype-phenotype investigation demonstrated association between the IL-10 -1082 A/G, IL-4 C/T and 221delT loci and poor pregnancy progress which manifested as (i) delivery of infants weighing <2000g, (ii) before 37 weeks of gestation. The findings of this study will strengthen our understanding of the pathophysiology underlying pregnancy complications and facilitate the further development of effective treatment strategies to reduce maternal and fetal morbidity and mortality.
AFRIKAANSE OPSOMMING: Die Wêreld Gesondheid Organisasie (WHO) klassifiseer voortydse kraam as kontraksie voor 37 volledige weke, met ‘n insidensie tussen 5-10%. Alhoewel pasiënte-sorg verbeter het, neem die tempo van voortydse geboorte steeds toe, wat ‘n groot impak het op moederstrefte en fetale mortaliteit en morbiditeit. Die komplekse kondisie van voortydse kraam sluit veelvoudige oorsake en risiko faktore in, wat die navorsing van kandidaat en / of biologiese merkers kompliseer. Die doel van hierdie prospektiewe studie, was die potensiële navorsing van genetiese assosiasies met voortydse kraam. Die studie kohort bevat opeenvolgende eerste bespreking van lae risiko primigravida swanger vrouens vanaf ‘n beperkte geografiese omgewing. Die studie kohort beslaan 421 [306 Kleurling en 115 Swart] swanger vrouens teenwoordig by die Paarl Hospitaal Verloskunde kliniek. Vervolgens was DNS geëkstraeer van bloedmonsters en geondersoek vir ‘n verskeidenheid van bekende polimorfismes in pro-inflammatoriese en antiinflammatoriese sitokiene, insluitend die nuwe sifting van die LGALS13 geen potensiaal vir variante wat ‘n impak op swangerskap uitkomste sal hê. Die siftings tegnieke toegepas, sluit in ‘n kombinasie van alleel-spesifieke amplifikasie, Multiphor enkelstring konformasie polimorfisme / heterodupleks analise, restriksie ensiem verterings en volgorde bepalings tegnieke. ‘n Betekenisvolle assosiasie was gedemonstreer tussen die IL-1RN*2-alleel en nadelige swangerskap, beperk tot voortydse kraam en die hipertensie groep. Die teenwoordigheid van die TNFα-308 A-alleel was geassosieer met algehele nadelige uitkomste en voortydse kraam. Daarby, was ‘n nuwe IL-1RN alleel geïdentifiseer in die kontrole groep. Mutasie sifting en opeenvolgende statistiese metodes, het ‘n assosiasie getoon tussen ‘n nuwe LGALS13 koderende variant, 221delT, en voortydse kraam in Kleurling vrouens. Twee voorafbeskryfde introniese variante (IVS2-22 A/G en IVS3+72 T/A), het ‘n betekenisvolle bewys opgelewer dat daar koppelings-onewewig bestaan tussen hierdie variante, en toon evolusionêre konservasie van ekson drie. Addisioneel was twee nuwe introniese variante ontdek, IVS2-36 G/A en IVS2-15 G/A, wat geen assosiasie getoon nie. In hierdie studie het ons ‘n nuwe seldsame koderende variante geïdentifiseer in die kontrole groep, waarvan twee nie-sinonieme variante was in ekson drie (M44V, N=2 en K87R, N=1) en ‘n stil variasie in ekson vier (P117P, N=1). Geleë in die koderende area van ekson drie, was ’n interessante variant [“hotspot’] ontdek, waarvan ses basisse in ‘n 11 basis paar area polimorfies is. Geen assosiasie was getoon met hierdie variante en swangerskap uitkomste nie. Verder was ‘n voorafbeskryfde 5' ‘promotor’ variant, -98 A/C, geïdentifiseer wat geen assosiasie getoon met nadelige swangerskap uitkomste nie. Onderverdeling van laat-aanvangs preeklampsie, het getoon dat die A-alleel ‘n betekenisvolle assosiasie getoon het met die ontwikkeling van laat pre-eklampsie. Genotipe-fenotipe interaksies het ’n assosiasie getoon tussen die IL-10 -1082 A/G, IL-4 C/T en 221delT lokusse en nadelige swangerskap uitkomste, wat manifesteer as (i) kraam van suigelinge wat <2000g weeg, (ii) geboorte voor 37 weke. Die bevindings van hierdie studie sal ons basiese kennis verbeter oor die patologie beskrywend aan swangerskap komplikasies, asook die fasilitering en ontwikkeling van effektiewe behandelings strategieë, om moederstrefte en fetale mortaliteit en morbiditeit te verminder.
22
李耀華 e Yiu-wah Lee. "Molecular genetic analysis of the polyol pathway in diabetic and galactosemic cataracts". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31234276.
Testo completo
23
High, Nicola Jane. "A molecular analysis of Escherichia coli cell surface antigens required for the colonisation of the urinary tract". Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35385.
Testo completoAbstract (sommario):
The uropathogenic Escherichia coli strain 20025 (04:K12:H-) elaborates at least four fimbrial antigens, Fy (F14), F12-rel, F13, F1C and secretes the toxin a-haemolysin. The work presented in this thesis demonstrates that the gene clusters encoding these five determinants are located within a 60-70kb region of the 20025 chromosome. The F14 fimbrial antigen produced by 20025 is a novel P-fimbriae serotype and exhibits a different binding specificity to the majority of P-fimbriae. To determine the basis of this apparent difference in cell surface receptor specificty a detailed molecular analysis of the F14 gene cluster is presented. The cloning and analysis of two other Escherichia coli surface antigens, the non-fimbrial adhesin NFA-1 and the K12 capsular polysaccharide is also described.
24
Schulte, Kathleen Q. "Mutagenized HLA DNA Constructs: Tools for Validating Molecular HLA Typing Methodologies". Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc500888/.
Testo completoAbstract (sommario):
This study describes the development and validation of mutagenized cloned DNA constructs, which correspond to the polymorphic regions of the class II region of the HLA complex. The constructs were used to verify the allelic specificity of primers and probes in polymerase chain reaction (PCR)-based HLA typing assays such as Sequence Specific Primers (SSP) and Sequence Specific Oligonucleotide Probes (SSOP). The constructs consisted of the entire polymorphic region of exon 2 of class II HLA allele sequences that included primer annealing sites or probe hybridization sites. An HLA allele sequence was inserted into a plasmid, cloned, then mutagenized to match a specific HLA allele, and finally, the correct clone was verified by bidirectional sequencing of the insert. Thus, the construct created a cloned reference DNA sample for any specific allele, and can be used to validate the accuracy of various molecular methodologies.
25
Vessey, S. J. R. "A molecular analysis of the T-cell receptor". Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:87b560f9-b1d6-4b12-9c94-fd1b4de397f6.
Testo completoAbstract (sommario):
The recognition of MHC-peptide ligands by the T cell receptor (TCR) is central to the induction of the adaptive immune response. This thesis describes the development of a bioassay for TCR recognition which was then used to undertake a molecular analysis of the TCR/MHC-peptide interaction. 1. A TCR-CD3ϛ chimeric receptor was stably expressed in the cell line RBL-2H3 to give the transfectant RBL-008. RBL-008 was shown to exhibit MHC-restricted peptide-specific responses to both cellular and multimerised recombinant HLA-A2-pol peptide targets (Chapter 3). 2. By competitively inhibiting the response of RBL-008 to HLAA2 pol complexes with monovalent soluble recombinant MHCpeptide complexes it was confirmed that the TCR makes significant contact with both the MHC and peptide parts of its ligand. Furthermore it was found that only a few peptides in a random mixture can prevent contact between the TCR and HLA-A2. This has implications for positive selection since it supports evidence suggesting that some TCRs can be selected on a wide range of unrelated peptides (Chapter 4). 2. The bioassay was used to examine the flexibility of TCRpeptide interactions using a panel of variant peptides designed on the basis of the previously published HLA-A2-pol peptide structure (Chapter 5). Several variant peptides were recognised by the TCR and interestingly one of these altered peptide ligands was actually recognised better than the index peptide, raising the prospect of designing 'improved epitopes'. 3. By mutating the β chain of TCR-CD3ϛ chimeric receptor it was shown that allelic variation in the TCR genes can have a significant effect on antigen recognition and may therefore be disease susceptibility candidates genes (Chapter 6). 4. The structural relationship between the V and C domains of the TCR was examined and found to be of considerable functional significance since disruption of this relationship resulted in loss of expression of the TCR-CD3ϛ receptor.
26
Butler, Lisa Maree. "Molecular analysis of the human Fas gene in colorectal cancer /". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phb9858.pdf.
Testo completo
27
王曉飛 e Xiaofei Wang. "Molecular characterization and cytogenetic analysis of chicken repetitive DNA sequences". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31239419.
Testo completo
28
Hui, Wing-sum, e 許永森. "Molecular and mutation analysis of hereditary multiple exostoses". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42577081.
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29
Cai, Guo Qin 1966. "Molecular genetic analysis of acetoacetate metabolism in Sinorhizobium meliloti". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37876.
Testo completoAbstract (sommario):
Many bacteria accumulate carbon stores as poly-3-hydroxybutyrate (PHB) when growth is limited but carbon availability is not. This stored carbon can then be utilized during conditions of limited carbon availability. The net PHB accumulation in the cell is dependent on the balance between PHB synthesis and degradation. Sinorhizobium meliloti accumulates PHB in the free-living stage but not in the symbiotic stage. The physiological role of the PHB cycle in S. meliloti is unknown. As a first step to understand the genetics of PHB degradation, transposon-generated mutants that were not able to use PHB degradation intermediates, such as 3-hydroxybutyrate and acetoacetate, as a sole carbon source, were isolated. Genetic mapping revealed that there were at least three chromosomal loci involved in acetoacetate metabolism. Identification of these three loci determined that in S. meliloti: (1) acetoacetyl-CoA synthetase (AcsA), encoded by acsA2 gene, rather than the enzyme acetoacetate:succinyl-CoA transferase, is the enzyme that catalyzes activation of acetoacetate to acetoacetyl-CoA; (2) PHB synthase, encoded by phbC, is required for acetoacetate utilization; (3) a putative transporter protein encoding gene, aau-3, may also be involved in acetoacetate metabolism. acsA2 and aau-3 were 78% linked in co-transduction, while phbC was mapped to somewhere else on the chromosome. Biochemical analysis revealed that acsA2::Tn5 mutants lacked AcsA activity but not acetoacetate:succinyl-CoA transferase activity, while phbC::Tn5 maintained similar level of AcsA activity as wild type in vitro. PHB was absent in the phbC mutant.One transposon-generated mutant, age-1, showed enhanced growth rate on acetoacetate medium. Genetic mapping and transductional analysis indicated that the location of the mutation in age-1 is tightly linked to acsA2. Fine mapping with PCR and DNA sequence techniques showed that Tn5 in age-1 was located at 132 by upstream of the putative translation start site of acsA2. Gene expression analysis indicated that age-1 insertion results in elevated transcription of acsA2. Thus enhanced growth rate on acetoacetate was due to the increased gene expression. acsA2 transcription was induced by acetoacetate and 3-hydroxybutyrate, and repressed by glucose and acetate.
All mutants formed root nodules that fixed nitrogen with varying decrease of impairment. Acetoacetate metabolism and the PHB degradation are not essential for symbiosis.
30
Ma, Huan, e 马欢. "Molecular analysis of ocular adnexal lymphomas in the search for potential biomarkers". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46921655.
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Flomerfelt, Francis Andrew. "Molecular genetic analysis of glucocorticoid-induced thymocyte apoptosis". Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/187007.
Testo completoAbstract (sommario):
I have used a molecular genetic approach to study early events in the gene network that precede apoptotic commitment in glucocorticoid-induced thymocyte apoptosis. A panel of recessive, apoptotic-deficient (Apt⁻) mutants were isolated that are cross resistant to several diverse apoptotic treatments. These results indicated that the signal pathways initiated by glucocorticoids, gamma radiation, and c-AMP analog treatment converge to a common apoptotic pathway. Complementation analysis of Apt⁻ cell lines has defined five independent complementation groups that appear to represent mutations in genes that are required for apoptotic commitment. In addition, I have characterized induced gene expression patterns characteristic of dexamethasone (dex)-induced apoptosis and have found that glutathione-s-transferase (GST), Dag8 (a gene of unknown function) and calmodulin (Cam) transcript levels are elevated following dex treatment. Dex-treatment of Apt⁻ cell lines does not change GST or Cam transcript levels which suggests that these cell lines are blocked in early steps of the apoptotic pathway. In contrast, the dominant oncogene, Bcl-2, blocks apoptosis and appears to affect a relatively late event in the apoptotic pathway since the pattern of dex-induced gene expression is normal in cells that express this protein. Since the Apt⁻ cells contain wild type levels of functional glucocorticoid receptor (GR), GST and Cam do not appear to be primary GR target genes, but seem to respond to cellular events that occur prior to apoptotic commitment. In support of this conclusion, it was found that GST transcript levels increase in calcium ionophore-induced apoptotic cells. In contrast, Dag8, transcript levels increased in dex-treated Apt⁻ cells indicating that Dag8 is most likely a primary GR target gene. Furthermore, Dag8 expression was found to be restricted to thymocyte containing tissues and its locus was mapped to the H2 complex of chromosome 17, a region that is known to contain many immunologically important genes. Finally, a model is presented to describe a common apoptotic pathway in murine thymocytes and proposes that an increase in oxidative stress precedes calcium mobilization in response to glucocorticoid treatment.
32
Yu, Yong Gang. "Molecular genetic analysis of host resistance to soybean mosaic virus". Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/37253.
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Remédios, Joana Fortuna dos. "Aspects of molecular ecology of carnivore viruses : sapovirus and coronavirus". Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2018. http://hdl.handle.net/10400.5/15510.
Testo completoAbstract (sommario):
Dissertação de Mestrado Integrado em Medicina VeterináriaCurrent knowledge on the epidemiology of many pathogens of wild animals is limited and little is known about their genetic diversity, geographic and host species range, and their potential to spread between wild, domestic and human species. This thesis, developed at the Leibniz Institute for Zoo and Wildlife Research, includes two studies that seek to contribute to increase the knowledge in this field. The first study aimed to test the hypothesis that consecutive outbreaks of Sapovirus (SaV) infection in spotted hyenas (Crocuta crocuta), detected by a previous study on this species in the Serengeti National Park, resulted from the emergence of antigenically different strains of the virus. Virus RNA was extracted from faecal samples obtained from three infected hyenas and amplified using conventional RT-PCR methods, with the aim of sequencing a fragment of the virus genome known to be important in determining the antigenic type of SaV strains. Although a diverse set of primer pairs were tried, only a partial sequence of the targeted gene was obtained from one sample, thus it was not possible to determine if the outbreaks of SaV infection among spotted hyenas in the Serengeti were caused by distinct antigenic strains. The second study targeted aminopeptidase N (APN), a protein known to work as the host cell receptor for a great number of alphacoronaviruses (α-CoVs). In vitro studies have demonstrated that canine and feline APNs can facilitate the entry of α-CoVs from different species into these carnivore’s cells. This work aimed to investigate the phylogenetic relation between APN from different carnivore species. A particular focus was given to the region known to interact with α-CoVs during cell entry, with the purpose to better understand the possibility of α-CoVs from particular host species successful extending their range of hosts. The detection of isoforms of APN was also sought. The amplification and sequencing of nine tissue samples of wild carnivores was performed using conventional RT-PCR and molecular cloning methods, followed by the phylogenetic analysis of the results. Seven partial sequences of APN were obtained and their phylogenetic relation corresponded to that of their animals of origin. However, the analysis of the specific region where the virus attaches revealed that the species from the families Hyaenidae and Herpestidae (suborder Feliformia) were phylogenetically more similar to the species from Caniformia suborder rather than those from Feliformia suborder. This suggests that α-CoVs that infect the species in these two families might extend their host range to species in Caniformia rather than Feliformia suborder. The results obtained complement the already existing information on both Sapovirus and APN.
RESUMO - Aspetos da ecologia molecular de vírus de carnívoros: Sapovirus e Coronavirus - O conhecimento atual sobre a epidemiologia de muitos agentes patogénicos em animais selvagens é limitado e pouco se sabe sobre a sua diversidade genética, a sua extensão geográfica e de espécies hospedeiras, e o seu potencial de propagação entre espécies selvagens, domésticas e humana. Esta tese, desenvolvida no Leibniz Institute for Zoo and Wildlife Research, inclui dois estudos que procuram contribuir para o aumento do conhecimento nesta área. O primeiro estudo procurou testar a hipótese de que surtos consecutivos de infeção por Sapovirus (SaV) em hienas-malhadas (Crocuta crocuta), detetados por um estudo prévio nesta espécie no Parque Nacional do Serengeti, resultaram da emergência de estirpes antigenicamente diferentes do vírus. O RNA do vírus foi extraído de amostras fecais obtidas de três hienas infetadas e amplificado usando métodos convencionais de RT-PCR, com o objetivo de sequenciar um fragmento do genoma viral que se sabe ser importante para a determinação do tipo antigénico das estirpes de SaV. Apesar de terem sido experimentados vários conjuntos de primers, apenas foi obtida uma sequência parcial do gene-alvo de uma amostra, pelo que não foi possível determinar se os surtos de infeção por SaV entre as hienas-malhadas no Serengeti foram causados por estirpes antigenicamente distintas. O segundo estudo visou a aminopeptidase N (APN), uma proteína conhecida como recetor celular para um grande número de alfa-coronavirus (α-CoVs). Estudos in vitro demonstraram que as APNs canina e felina conseguem facilitar a entrada de α-CoVs de diferentes espécies nas células destes carnívoros. Este trabalho teve por objetivo investigar a relação filogenética entre a APN de diferentes espécies de carnívoros. Uma atenção particular foi dada à região que se sabe interagir com os α-CoVs durante a sua entrada na célula, com o propósito de melhor compreender a possibilidade de α-CoVs de uma espécie hospedeira particular alargarem com sucesso o seu leque de hospedeiros. Procurou-se também a presença de isoformas da APN. A amplificação e sequenciação de nove amostras de tecidos de carnívoros selvagens foram realizadas usando métodos convencionais de RT-PCR e métodos de clonagem molecular, seguidos da análise filogenética dos resultados. Sete sequências parciais da APN foram obtidas e a sua relação filogenética correspondeu à dos seus animais de origem. No entanto, a análise da região específica onde o vírus adere revelou que as espécies das famílias Hyaenidae e Herpestidae (subordem Feliformia) eram filogeneticamente mais semelhantes a espécies da subordem Caniformia do que da subordem Feliformia. Isto sugere que α-CoVs que infetem espécies desta duas famílias possam estender a sua variedade de hospedeiros a espécies da subordem Caniformia em vez da subordem Feliformia. Os resultados obtidos complementam a informação já existente acerca do SaV e do APN.
N/A
34
Zhu, Rui, e 朱睿. "Liver-intestine cadherin (CDH17) in hepatocellular carcinoma: molecular analysis and clinicalimplications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43703793.
Testo completo
35
Fisher, Scott Andrew. "Clinical and molecular analysis of the hepatitis C virus". University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0099.
Testo completoAbstract (sommario):
[Truncated abstract] The hepatitis C virus (HCV) is a significant human pathogen for which there are limited post-infection therapies and no effective vaccine. Research into HCV is notoriously difficult due to the absence of suitable in vitro and in vivo model systems with which to study the virus. Furthermore, our understanding of HCV host interaction is limited and the mechanisms by which it subverts the host immune system remains largely unknown. Due to the difficult nature associated with studying HCV, the work presented in this thesis was designed to addresses a broad range of issues relating to both clinical and molecular aspects of HCV. Chronic HCV infection is often associated with the development of cirrhosis, end stage liver disease and hepatocellular carcinoma. To date, histological examination of liver biopsies provides the only approved method with which to assess the level of liver damage. While clinically informative, liver biopsies are highly invasive and may be contraindicative for patients such as haemophiliacs. Cytokine specific ELISPOT assays were used to determine whether cytokine secretion from PBMCs isolated from chronically infected HCV patients could be used as a non-invasive method to assess liver damage. Chronically infected patients with sever liver fibrosis demonstrated a significantly reduced ability to produce IFN-γ in response to HCV Core, but not other unrelated antigens, indicating that decreased IFN-γ secretion by PBMCs in response to HCV antigen could be used as a non-invasive marker for the development of liver fibrosis ... A series of HCV expression vectors covering the full length of the HCV ORF were constructed and their expression extensively tested before being used to assess the ability of HCV proteins to interact with Jak/STAT mediated Type I IFN signalling. Additionally, an alternative set of HCV IRES-EGFP reporter vectors were developed and used to access HCV IRES functionality between different eukaryotic cell lines. HCV Core protein expressed alone or in concert with E1-P7 and non-structural protein NS5B were shown to significantly reduce Jak/STAT mediated IFN expression. While the influence of HCV Core on Type I IFN signalling is consistent with previous reports in the literature, these results identify a new role for NS5B as a possible candidate protein involved in inhibition of Type I IFN signalling.
36
Cullen, Lara Michelle. "Molecular analysis of hereditary haemochromatosis". Thesis, Queensland University of Technology, 1999.
Cerca il testo completo
37
Wang, Yongfeng, e 王永峰. "Molecular analysis of ammonia oxidizing prokaryotes in mangrove wetlands and factors affecting their dynamics". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50434421.
Testo completoAbstract (sommario):
Ammonia/ammonium-oxidizing prokaryotes (AOPs) play a crucial role in nitrogen transformation in the natural ecosystems including mangrove wetlands. The objectives of the present study were to investigate the spatial and temporal distribution of AOPs in the mangrove wetland sediments in subtropical Hong Kong and their ecophysiology.
When AOP communities and abundances in a natural coastal mangrove wetland and a constructed freshwater wetland were compared, the constructed freshwater wetland contained a broader range of phylotypes, higher diversity, more complex community structures, and more uneven abundances of AOPs than the mangrove wetland. Typha angustifolia affected the community structures of all AOPs and enhanced their abundances in the rhizosphere. Both Phragmites australis and Cyperus malaccensis showed some effects on the community structures of ammonia-oxidizing bacteria (AOB), but little effects on those of anaerobic ammonium oxidizing (anammox) bacteria or ammonia-oxidizing archaea (AOA). Kandelia obovata had no detectable effect on any group of the AOPs due to their smaller size.
AOPs in oxic and anoxic sediments of a protected mangrove wetland were investigated in both winter and summer. Seasonality had little effect on community structure and abundance of anammox bacteria. AOA community structures were stable between the two seasons, but AOA abundance was significantly higher in winter than summer. The community structures of AOB were different between winter and summer, but the abundance in winter was apparently higher than that in summer. Sediment type had a noticeable influence on community structure and abundance of anammox bacteria. No apparent difference in AOA community structures between the different types of sediments in winter was observed, but the oxic sediments showed obviously different AOA community structures from anoxic sediments in summer. Sediment type had little effect on AOB community structures, but AOB abundance in oxic sediments was obviously lower than anoxic ones in both seasons.
Addition of acetate or leaf litter into sediment inhibited the growth of anammox bacteria in laboratory incubation. The inhibition of anammox bacteria by acetate was more pronounced than by leaves. Acetate and leaf litter did not affect AOA community structures, but promoted their growth. Both acetate and leaf litter affected the AOB community structures and promoted their growth in the early phase of the incubation. The promoting effects by leaf litter were more obvious than by acetate.
Allylthiourea effectively inhibited the growth of both AOA and AOB in laboratory incubation, but only slightly for anammox bacteria. Acidic condition altered AOB community structure, but affected anammox bacteria and AOA slightly. Alkaline condition strongly affected community structures of anammox bacteria and AOA, but slightly for AOB. Alkaline condition inhibited the growth of anammox bacteria, but promoted AOA and AOB slightly. Increase in salinity resulted in higher diversity of anammox bacteria, and AOA and AOB might have species specific preference for salinity. High salinity promoted anammox bacteria growth; inhibited AOA for 5-10 days, but promoted them afterward; and promoted AOB. Totally, this study revealed new and specific information on the spatial and temporal distribution of AOPs in mangrove wetland and factors affecting their ecophysiology.published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
38
Campeau, Eric. "Molecular genetics of biotin-dependent enzymes : mutation analysis, expression and biochemical studies". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0019/NQ55308.pdf.
Testo completo
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Julies, Monique G. "Molecular-genetic analysis of Hirschsprung's disease in South Africa". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51835.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2000.ENGLISH ABSTRACT: Hirschsprung's disease, or aganglionic megacolon, is a common cause of intestinal obstruction in neonates and is associated with the congenital absence of intrinsic ganglion cells in the myenteric and submucosal plexuses of the gastrointestinal tract. The affected area is usually restricted to the distal part of the colon (short segment disease), but total colonic or intestinal involvement occurs in some patients (long segment disease). DNA analysis was performed on samples from 53 unrelated sporadic HSCR patients to search for mutations in RET proto-oncogene, endothelin-B receptor (EDNRB) and endothelin-3 (EDN3) genes. The patients were from different ethnic groups in South Africa, including 29 coloured, 14 white (Caucasian) and 9 black individuals. The origin of 1 patient was unknown. PCR HEX-SSCP analysis of the RET protooncogene revealed one previously described (P973L) and five novel mutations (V202M, E480K, IVS10-2A1G, D771N, IVS19-9Crr), likely to cause or contribute to the HSCR phenotype. Nine polymorphisms were also identified in the RET protooncogene, of which four were novel (IVS6+56deIG, IVS13-29Crr, IVS16-38deIG, X1159) and five previously described (A45, A432, L769, S904, R982). All the mobility shifts detected in the EDNRB gene represented polymorph isms (A60T, S184, 1187, V234, L277, IVS3-6Crr, IVS4+3A1G). No sequence variants were identified in the EDN3 gene. The majority of mutations in the RET proto-oncogene (28.6%) were identified in coloured patients while no mutations were identified in black patients. A mutation in RET was identified in two of 14 patients (14%) presenting with HSCR and Down's syndrome compared to 6 mutations identified in 9 of 39 patients (23%) with only HSCR. The fact that Down's syndrome patients have a high chance of developing HSCR, implies the involvement of modifier gene(s) in a HSCR/Oown's syndrome phenotype. This study demonstrated that, within the South African HSCR patient population, the RET proto-oncogene is the major susceptibility gene, whereas EDNRB and EDN3 may contribute only to a minority of cases. In 81% of patients no disease-causing mutation could be identified, which is in keeping with the heterogeneous nature of HSCR. The identification of mutations in HSCR patients would in future lead to improved and accurate counselling of South African HSCR patients and their families.
AFRIKAANSE OPSOMMING: Hirschsprung se siekte (HSCR), ook bekend as aganglionosis megakolon, is 'n algemene oorsaak van intestinale obstruksie in pasgeborenes en word geassosieer met die kongenitale afwesigheid van intrinsieke ganglion selle, in die miênteries en submukosa pleksus van die gastrointestinale kanaal. Alhoewel die aangetaste deel hoofsaaklik by die distale area van die kolon geleê is (kort segment siekte), kom totale koloniese of intestinale betrokkenheid ook in sommige pasiënte voor (lang segment tipe). Molekulêre ONS analise van 53 nie-verwante Suid Afrikaanse sporadiese HSCR pasiênte (29 kleurlinge, 14 blankes, 9 swartes en 1 individu van onbekende oorsprong) is uitgevoer in die RET proto-onkogeen, endoteel-B reseptor (EDNRB) en endoteel-3 (EDN3) gene. Heterodupleks-enkel string konformasie polimorfisme (HEX-SSCP) analise van polimerase ketting reaksie (PKR) geamplifiseerde produkte van die RET proto-onkogeen het gelei tot die identifikasie van vyf nuwe mutasies (V202M, E480K, IVS10-2A1G, D771N, IVS19-9CIT) en een bekende mutasie (P973L). Vier nuwe polimorfismes (IVS6+56deIG, IVS13-29Crr, IVS16-38deIG, X1159) en vyf bekende polimorfismes (A45, A432, L769, S904, R982) is ook aangetoon. Sewe polimorfismes (A60T, S184, 1187, V234, L277, IVS3-6CIT, IVS4+3A1G) is in die EDNRB geen geïdentifiseer. Geen veranderinge is in die EDN3 geen waargeneem nie. Die meerderheid mutasies waargeneem in die RET protoonkogeen is in die kleurling populasie (28.6%) waargeneem, terwyl geen mutasies in die swart populasie geïdentifiseer is nie. 'n RET mutasie is in twee van 14 (14%) pasiênte met 'n HSCR en Down's sindroom fenotipe waargeneem, in vergelyking met mutasies geïdentifiseer in 9 van 39 pasiënte (23%) met slegs HSCR. Die algemene voorkoms van Down's sindroom met HSCR, impliseer die rol van ander gene in die HSCRI Down's sindroom fenotipe. Die meerderheid mutasies wat aanleiding gee tot die HSCR fenotipe kom voor in die RET proto-onkogeen (19%), terwyl slegs polimorfismes in die EDNRB geen waargeneem is. Geen HEX-SSCP bandpatroon veranderinge is in die EDN3 geen waargeneem nie. Ongeveer 81% van die Suid Afrikaanse HSCR pasiënte was mutasie-negatief wat dui op die heterogene aard van die siekte. In die toekoms sal analise van siekte-verwante mutasies in die RET geen lei tot akkurate diagnose en verbeterde genetiese voorligting van HSCR in die Suid-Afrikaanse populasie.
40
Lee, Kwok-ho, e 李國豪. "Molecular analysis of anammox, AOA and AOB in high nitrogen sediment and wetlands". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45544190.
Testo completo
41
Xu, Yunhe. "Molecular and diagnostic aspects of the protein p41 of HHV-6 and silencing of the CD46 receptor by RNA interference /". Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-553-0.
Testo completo
42
Human, Veronique. "Molecular analysis of genes involved in iron overload implicated in oesophageal cancer". Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/391.
Testo completo
43
Luo, Shun. "Molecular analysis of glycogen phosphorylase-1 gene expression during the development of dictyostelium discoideum". Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39711.
Testo completoAbstract (sommario):
The cellular slime mold, Dictyostelium discoideum, has two developmentally regulated forms of the enzyme glycogen phosphorylase, which are encoded by two distinct, but related genes (Rutherford, et. aI., 1991). A complementary DNA (cDNA) encoding glycogen phosphorylase-}, gp-l, was isolated from a λgtll expression library made from amoebae stage mRNA. The 5' upstream region of the gp-l gene was cloned by inverted polymerase chain reaction (IPCR) and partial genomic DNA library screening. The gp-l gene was found as one copy or low copy number gene in the Dictyostelium genome, and an adjacent 22 kilobase pair region was physically mapped. The deduced amino acid sequencing analysis revealed that there were 862 amino acid residues encoded by the gp-1 mRNA of 2729 nucleotides. It was also found that most regulatory and catalytic domains were similar to those in other glycogen phosphorylases. One intron of 139 bp was verified beginning after the 40th amino acid codon. The transcriptional start site was determined at 134 nucleotides upstream of the ATG initiation codon. Gel retardation assays demonstrated that there were at least two nuclear DNA binding proteins from vegetative amoebae (V 1 and V2 factors) and two from developing cells (D 1 and D2 factors). Experiments with a luciferase reporter gene suggested that a basal expression of the gp-l gene can be conferred by the 5' region containing 363 bp upstream of the ATG codon and the entire regulatory region is located at 157 to 700 bp upstream of the ATG site. It was also demonstrated that the 363 bp deletion fragment did not support cyclic AMP (cAMP) responsiveness of the gp-l gene. DNase I footprinting mapped two regions that were protected by nuclear DNA binding proteins and one of them was a palindromic sequence: CAAGTCGCTIG.Ph. D.
44
Lin, Ying Chen, e 林映辰. "Functional analysis of anther-specific genes essential for pollen exine development and male fertility in tobacco". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B50534178.
Testo completoAbstract (sommario):
In flowering plants, pollen grains are surrounded by extremely strong outer walls providing solid and firm structure for protecting pollen and species-specific interactions with female stigma. The outer wall of pollen, referred to as exine, is composed of sporopollenin polymer, but the composition and synthesis of sporopollenin remains poorly understood. Previous studies have indicated that several genes such as Fatty Acyl-CoA Synthetase (ACOS5), Polyketide Synthases (PKSA and PKSB), and Tetraketide α-Pyrone Reductase (TKPR1) take part in the biosynthesis of sporopollenin in Arabidopsis thaliana. The existence of ancient biochemical pathways for sporopollenin biosynthesis has been widely proposed but experimental evidence from plant species other than Arabidopsis is not extensively available. In this study, two homologous PKS genes, NtPKS1 and NtPKS2, were found in tobacco (Nicotiana tabacum). Results of RT-PCR and in situ hybridization revealed that NtPKS1 and NtPKS2 are specifically and transiently expressed in tapetal cells during microspore development in tobacco anthers. RNAi plants of NtACOS1 and NtPKS1 were investigated. Comparing with wild-type tobacco (SR1), abnormal pollens, defect exine structure, and male sterility were found in the RNAi lines. Enzymatic assays show that NtPKS1 and NtPKS2 encode anther-specific enzymes using fatty acyl-coenzyme A and p-coumaroyl coenzyme A as substrates to yield tri- and tetra- ketide α-pyrone and bisnoryangonin respectively. In this study, the metabolic steps catalyzed by the anther-specific acyl- CoA synthetase (ACOS), polyketide synthase (PKS), and tetraketide α-pyrone reductase (TKPR) were investigated. Using fatty acids as starting substrates, sequential activities of heterologously-expressed tobacco enzymes NtACOS1, NtPKS1, and NtTKPR1 resulted in the production of reduced tetraketide α- pyrones which propose to contribute to the biosynthesis of sporopollenin precursors in tobacco.published_or_final_version
Biological Sciences
Master
Master of Philosophy
45
Bruiners, Natalie. "Investigating the Human-M. tuberculosis interactome to identify the host targets of ESAT-6 and other mycobacterial antigens". Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71977.
Testo completoAbstract (sommario):
Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: The causative agent of human tuberculosis, Mycobacterium tuberculosis, is an intracellular pathogen that secretes virulence factors, namely ESAT-6 and CFP-10, as substrates of the ESX-1 secretion system. It is hypothesised that these substrates interact with host proteins in a targeted manner in order to elicit a required immune response, and they have been shown to be involved in processes related to pro-inflammatory responses, necrosis, apoptosis, membrane lysis and cytolysis. However, the biological function of ESX-1 substrates during host-pathogen interactions remains poorly and incompletely understood. Therefore, the present study was designed to gain insight into the role of the ESX-1 secretion system substrates in host-pathogen interactions and to identify how M. tuberculosis mediates the response of the human host. In this study, a cDNA yeast two-hybrid library was constructed from human lung mRNA, to identify mycobacterial-host protein-protein interactions that occur within the lung alveoli. The ESX-1 secretion system substrates, ESAT-6 and CFP-10, were cloned in-frame into the pGBKT7 vector, which was used in the yeast two-hybrid system to screen the lung cDNA library in Saccharomyces cerevisiae. The ESAT-6 and CFP-10 screens identified 79 and 19 positive colonies, respectively. Of the total number of clones characterised, only two in-frame inserts were identified with the ESAT-6 screen, corresponding to the human proteins filamin A and complement component 1, q subcomponent, A chain (C1QA). In addition, the screen with CFP-10 also identified C1QA as binding partner. Subsequent in vitro and in vivo experiments were unable to confirm the putative interactions of C1QA with ESAT-6 and CFP-10. However, the interaction between filamin A and ESAT-6 was demonstrated and confirmed by both in vivo co-localisation and co-immunoprecipitation. Furthermore, the degradation of filamin A in the presence of ESAT-6 was shown to be reflective of cytoskeleton remodelling and the induction of cell death. The work presented here suggests that as ESAT-6 gains access to the cytosol, it initiates cell death by inducing destabilisation of the cytoskeleton cell structure. This may possibly be driven by the interaction of ESAT-6 and filamin A. Finally, we also initiated an investigation of the identified putative binding partners (filamin A and C1QA) as possible genetic markers for genetic susceptibility studies to tuberculosis. A case-control analysis was performed involving 604 cases, of which 109 were Tuberculous Meningitis (TBM), and 486 were controls from the South African Coloured (SAC) population within the Ravensmead-Uitsig catchment area. The results of this analysis demonstrated a novel association of a regulatory variant (rs587585) located upstream of the C1QA gene and demonstrated an increasing trend towards increased values in tuberculosis patients with the associated genotype. This study has contributed significantly to our understanding of human-mycobacterial hostpathogen protein-protein interactions and has opened the way for future studies further exploring the consequences and function of the identified ESAT-6-filamin A interaction. It has also led to the identification of a novel genetic association with tuberculosis. Finally, it demonstrates the usefulness of the yeast two-hybrid system to identify potential proteinprotein (host-pathogen) interactions that can lead to additional important and exciting research.
AFRIKAANSE OPSOMMING: Die organisme wat tuberkulose veroorsaak, Mycobacterium tuberculosis, is `n intrasellulȇre patogeen wat virulensie faktore afskei, naamlik ESAT-6 en CFP-10, as substrate van die ESX-1 sekresiesisteem. Daar word vermoed dat hierdie substrate met gasheerproteïene in „n teiken wyse interaksie het om `n vereiste immuunreaksie voort te bring. Hierdie substrate is betrokke by prosesse soos pro-inflammatoriese reaksies, nekrose, apoptose, membraanlise en sitolise. Die biologiese funksie van die ESX-1 substrate tydens gasheer-patogeen interaksies word egter tans swak en onvolledig verstaan. Daarom was die huidige studie ontwerp om insig te bekom oor die rol hiervan in gasheer-patogeen interaksies en om te identifiseer hoe M. tuberculosis die reaksie teenoor die gasheer bemiddel. In hierdie studie was `n komplementȇre deoksiribonukleïensuur (kDNS) gis twee-hibried biblioteek gemaak vanaf long boodskapper ribonukleïensuur (bRNS) om proteïen-proteïen interaksies wat in die long plaasvind, te identifiseer. Die substrate van die ESX-1 sekresiesisteem, ESAT-6 en CFP-10, is in volgorde gekloneer in die pGBKT7 vektor en is gebruik om die long kDNS biblioteek in Saccharomyces cerevisiae te ondersoek. In die soeke na interaksies met ESAT-6 and CFP-10, was 79 en 19 positiewe kolonies onderskeidelik geïdentifiseer. Van die aantal klone, was slegs twee volgordes in-leesraam geïdentifiseer met ESAT-6. Hierdie proteïene het ooreengestem met filamin A en “complement component 1, q subcomponent, A chain” (C1QA). Bykomend hiertoe, is C1QA ook geïdentifiseer as „n bindende vennoot met CFP-10. Daaropvolgende in vitro and in vivo eksperimente kon nie die vermeende interaksie van C1QA met ESAT-6 en CFP-10 bevestig nie. Maar die interaksie tussen filamin A en ESAT-6 kon wel gedemonstreer word deur die gebruik van mede-lokalisering en medeimunopresipitasie. Die afbreek van filamin A in die teenwoordigheid van ESAT-6 is ook aangetoon en blyk „n weerspieëling te wees van sitoskelet hermodellering en die induksie van seldood. Die werk wat hier aangebied word, dui daarop dat soos ESAT-6 toegang kry tot die sitosol, inisieër dit seldood deur die destabilisaisie van die sitoskelet selstruktuur. Dit word moontlik aangedryf deur die interaksie van ESAT-6 met filamin A. Laastens het ons `n ondersoek van die geïdentifiseerde bindingsvennote (filamin A and C1QA) as moontlike genetiese merkers vir genetiese vatbaarheidsstudies vir tuberkulose uitgevoer. `n Pasiënt-kontrole studie is gedoen waarby 604 individue ingesluit is, waarvan 109 gediagnoseer is met Tuberculosis Meningitis (TBM), en die ander 486 kontrole individue was van die Suid Afrikaanse Kleurling (SAC) bevolking binne die Ravenmead-Uitsig opvanggebied. Die resultate het „n nuwe assosiasie van „n regulerende variant (rs587585) wat stroomop van die C1QA geen gelokaliseer is, getoon. Hierdie variant het `n verhoogde neiging in tuberkulose pasiënte met die geassosieërde genotipe getoon. Hierdie studie het `n beduidende bydrae gemaak tot ons begrip van menslike-mikobakteriese gasheer-patogeen proteïen-proteïen interaksies. Hierdie resultate het die weg oopgemaak om die gevolge en funksie van die geïdentifiseerde ESAT-6-filamin A interaksie verder te ondersoek. Dit het ook aanleiding gegee tot die identifikasie van `n genetiese assosiasie met tuberkulose. Om saam te vat, hierdie werk bewys die bruikbaarheid van die gis twee-hibriede sisteem, om potensiële proteïen-proteïen interaksies te ontdek wat die moontlikheid het om aanleiding te gee tot addisionele navorsingsvrae.
The National Research Foundation,
Harry Crossley Foundation
Medical Research Council of South Africa
Stellenbosch University Postgraduate bursary
Prof. Paul van Helden
46
Agenbag, Gloudi. "Molecular genetic analysis of familial breast cancer in South Africa". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/953.
Testo completo
47
Zhian, Samaneh. "Molecular Genetic Analysis of CRELD1 in Patients with Heterotaxy Disorder". PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/410.
Testo completoAbstract (sommario):
Heterotaxy refers to the abnormal arrangement of internal organs in relation to each other. Model organism studies have shown that functions of more than eighty genes are required for normal asymmetric left-right organ development. CRELD1 has been shown to be necessary for proper heart development and mutations in CRELD1 are known to increase risk of cardiac atrioventricular septal defects (AVSD). AVSD is the most common form of heart defect associated with heterotaxy, and we have previously shown that some individuals with heterotaxy-related AVSD have mutations in CRELD1. Therefore, we propose to examine the CRELD1 gene in a large sample of patients with heterotaxy syndrome. Our goal was to determine if mutations in CRELD1 are associated with other manifestations of heterotaxy or if they only coincide with AVSD. To achieve this aim, a sample size of 126 patients with heterotaxy collected by Dr. Belmont, Baylor college of Medicine, Texas, with approximately 66% of the heterotaxy population with different types of heart defects, were used for this study. Ten exons, promoter regions, and regulatory elements in the introns of CRELD1 gene were sequenced and analyzed. In this study three different heterozygous missense mutations in CRELD1 were identified in three unrelated individuals. These three individuals were diagnosed with different forms of heart defects in addition to AVSD. All three mutations were identified in highly conserved regions of CRELD1 possibly altering the CRELD1 properties. This demonstrates that mutations in CRELD1 may increase the susceptibility of AVSD in heterotaxy population. This information can help us to find factors effecting disease susceptibility in heterotaxy patients since the heart defects are a complex trait with incomplete penetrance.
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Chang, Yea-wen, e 張雅雯. "Application of molecular genetic techniques to the study of major histocompatibility complex class II allelic associations with insulin-dependent diabetes mellitus in Chinese". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31213960.
Testo completo
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Varga, Andrea Erica. "Molecular characterisation, regulation and evolutionary analysis of uroplakin 1B : a tetraspanin family member /". Title page, errata, table of contents and summary only, 2003. http://hdl.handle.net/2440/37940.
Testo completoAbstract (sommario):
Uroplakin 1B (UPKIB) is an integral structural protein interacting with uroplakins 1A, 2 and 3 to form hexameric plaques along the bladder lumen in the asymmetric unit membrane of urothelial umbrella cells in humans and other mammals. UPKIB mRNA expression is deregulated in transitional cell carcinomas (TCCs), however the mechanisms of regulation of UPKIB have not been established. Using genome databases, a Xenopus UPKIB homologue was identified. Maximum Parsimony and BAMBE (Bayesian Analysis in Molecular Biology and Evolution) data support a close evolutionary relationship between mammalian and amphibian UPKIB mRNA. Using Unigene, UPKIB human expressed sequence tags were identified in tissues including brain, skeletal muscle and liver, suggesting the relatively widespread distribution of this membrane protein. The UPKIB genomic structure was also deduced using genome databases. Contig AC083800, identified in a high throughput genomic sequence database, spanned UPKIB and 9 exons and 8 introns were defined. A 67bp 5' untranslated region was identified using 5' rapid amplification of cDNA ends. This product was sequenced and a putative UPKIB promoter and transcription start site was deduced. Contig AC083800 spanned the transcription start site and putative promoter. Transcription factor binding motif prediction programs detected no TATA box, but did predict a CCAAT box and several binding motifs including 4 Sp-1 sites and a NFKB site. A weak CpG island was identified within a 0.5kb region including the putative promoter, exon 1 and intron 1, which was 54% GC rich with CpG:GpC ratio of 0.46, containing 15 CpG dinucleotides. Seven TCC cell lines and five peripheral blood lymphocyte samples were analysed for UPKIB expression using RT-PCR and two cell lines expressed UPKIB transcripts. Eleven CpG sites in the putative promoter were investigated for methylation using bisulfite modification analysis in normal PBL, TCC cell lines and patient TCC samples. An inverse correlation was established in TCC cell lines between UPKIB mRNA expression and degree of methylation. 5-Aza-2'deoxycytidine induced UPKIB mRNA expression in T24 cells, previously observed not to express UPKIB. Sequence analysis of patient samples revealed more complex CpG methylation patterns, reflecting tumour heterogeneity. In summary, the uroplakin 1B gene has been characterised and one mechanism of regulation of gene expression involves methylation.Thesis (Ph.D.)--Dept of Surgery, 2003.
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Halpern, Melissa Dale. "The in vivo and in vitro effects of diethyldithiocarbamate on autoimmune New Zealand Black/White F₁ hybrid, MRL/Mp-lpr/lpr and related and normal murine strains". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184940.
Testo completoAbstract (sommario):
New Zealand Black/White F₁ hybrid (NZB/W) and MRL/Mp-lpr/lpr (MRL/lpr) mice spontaneously develop a Systemic Lupus Erythematosus-like autoimmune disease. While the primary immunologic defect in the NZB/W is due to B cells, in the MRL/lpr it is a result of T cell abnormalities. Diethyldithiocarbamate (DTC), an agent suggested to enhance T cell function, was used to treat both strains. Weekly treatment of NZB/W mice with 25 mg/kg DTC had no significant effect upon survival or autoantibody levels but did induce changes in cell surface antigen expression. MRL/lpr mice treated with DTC displayed normalization of cell surface antigen expression (particularly increased expression of Lyt-2, macrophage markers and Lyt-2⁺/L3T4⁺ thymocytes), decreased lymphoproliferation and thymic atrophy, decreased serum autoantibody levels and kidney deposition of C3 and IgM, restored responses to mitogens and significantly prolonged survival. To determine both the influence of MRL background and lpr genes and to better understand on what cell populations DTC effects, changes in cell surface antigen expression were examined in DTC treated MRL-+/+, Balb/c, and Balb/lpr strains. The only consistent similarities observed between all strains tested were DTC induced changes in Mac-1 splenocyte surface antigen expression. In vitro studies showed DTC to have variable effects upon the mitogenic responses of lymphoid cells to phytohemagluttinin, but DTC alone stimulated both MRL/lpr and Balb/lpr lymphocytes. DTC stimulated the null cell population that predominates in lpr gene-bearing mice, but all observed in vitro effects of DTC were dependent upon the adherent cell population included in culture. DTC had no apparent direct effects upon adherent cells alone however. These studies have shown that DTC is capable of positive effects upon one autoimmune murine strain, the MRL/lpr, but not the NZB/W. DTC appears to affect macrophages, but other cell populations are required to obtain full activity of this compound. The variable effects of DTC emphasize the need to define the immunopathology of individual patients with autoimmune disease before initiating treatment with immunomodulative therapy.