This thesis addresses contemporary debates in the sociology of science, the sociology of media and the public understanding of science by examining the UK television and print media coverage of three substantive scientific issues. The first case study follows the debate as to whether a Martian meteorite (ALH 84001) provided evidence of ancient bacterial life-forms that could prove primitive life had once existed on Mars. The second case study tracks the use of cell nucleus replacement to “clone” mammals. The third case study examines the scientific and political controversy over the existence, symptoms, causes and response to “Gulf War syndrome”. The empirical research employed methodologies developed at the Glasgow Media Group, providing a comparative analysis of the production, content and reception of news media coverage of the case studies. The methods included interviews with scientists, journalists, media professionals and interest groups, a two-year content analysis of press and television news and focus group interviews. The content analysis discovered that media coverage of the case studies was extensive, unevenly distributed over time and emphasised scientific and science-based controversy as news values. The production analysis highlighted the importance of the interaction between scientific institutions and the media. For example, science journalists regularly draw on scientific journals as credible source material. The scientific community actively maintained this situation through information subsidies as a way of generating science news. The reception analysis demonstrated that news media, especially television news, provided an important source of information for audience members. Audience members were active consumers of science news, based on their education, gender, age and personal experience of science. Motivation to consume science news was also a key factor for audience members, varying according to the scientific issue being covered by the media. Overall, this thesis has highlighted the contested interactions that construct and interpret news media coverage of science. By analysing these complex interactions, this thesis contributes to contemporary concerns about the public presentation of science.

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Castor (Ricinus communis L.) is a high-yielding oilseed crop native to tropical Africa. The seed contains ~60% oil by weight, yielding approximately 1,200 kg of oil per hectare. The oil is composed of ~90% ricinoleic acid, a unique hydroxylatty acid. Its unique composition provides castor oil with distinctive characteristics important for industrial use. Unfortunately, this valuable oilseed has not been widely cultivated in the United States since 1972, due in part to the presence of ricin in the seed. Ricin is a highly toxic lectin found in the endosperm of mature castor seed. This project sought to silence ricin production through the introduction of an RNAi element into the castor genome. The RNAi vector (pC1-RKO) containing a segment of ricin mRNA and its inverted repeat separated by a chalcone synthase A intron from pFGC5941 enclosed in a pCambia1301 backbone was created, verified via sequencing, and transformed into Agrobacterium tumefaciens for castor transformation. Fungal contamination was a serious concern; successful disinfestation used a 10-minute wash with 0.1% mercuric chloride (w/v). Media supplemented with 6-benzylaminopurine generated healthier shoots from embryo axes dissected from mature seed compared to thidiazuron-treated mesocotyls dissected from mature seed. Short treatments of thidiazuron on 6-benzylaminopurine initiated shoot cultures showed greater shoot proliferation on embryo axes dissected from mature seed. Rooting occurred with incubation on half-strength medium containing naphthaleneacetic acid or indole-3-butyric acid; however, naphthaleneacetic acid produced hardier roots which better survived acclimatization. Inoculation of embryo axis explants after 2 days pre-culture improved survivability. Likewise, transformations using A. tumefaciens cultures of 0.5 O.D.600 and lower did not lead to downstream bacterial contamination. The pCambia1304 vector was used as a test plasmid for refinement of the transformation protocol. Of the 870 pCambia1304 inoculation explants, 2 survived hygromycin screening and showed gusA activity. Of the 2,500 pC1-RKO inoculated explants, 6 survived hygromycin selection and rooted. Further analysis via PCR, end-point RT-PCR, and Western and dot-blotting showed these to be non-transformed and ricin content unaffected.

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Kwok Hin-Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 84-100). / Abstracts in English and Chinese. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgement --- p.vi / Table of contents --- p.vii / List of figures --- p.xi / List of tables --- p.xiv / Symbols and abbreviations --- p.xv / List of fish names mentioned in the thesis --- p.xviii / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Gonadotropins / Chapter 1.1.1 --- Structure --- p.1 / Chapter 1.1.2 --- Function --- p.4 / Chapter 1.2 --- Gonadotropin receptor / Chapter 1.2.1 --- Structure --- p.5 / Chapter 1.2.2 --- Expression --- p.7 / Chapter 1.2.3 --- Signaling / Chapter 1.2.3.1 --- cAMP-mediated pathway --- p.7 / Chapter 1.2.3.2 --- Phospholipase C-mediated pathway --- p.9 / Chapter 1.2.4 --- Regulation of expression --- p.12 / Chapter 1.2.5 --- Desensitization of receptors / Chapter 1.2.5.1 --- Uncoupling --- p.13 / Chapter 1.2.5.2 --- Internalization --- p.13 / Chapter 1.3 --- Structure of ovarian follicles --- p.14 / Chapter 1.4 --- The project objectives and long-term significance --- p.16 / Chapter Chapter 2 --- Cloning and Characterization of Zebrafish Follicle-stimulating Hormone (FSH) and Luteinizing Hormone (LH) Receptors ´ؤ Evidence for Distinct Functions of FSH and LH in Follicle Development / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Materials and Methods / Chapter 2.2.1 --- Animals and chemicals --- p.22 / Chapter 2.2.2 --- Isolation of total RNA --- p.22 / Chapter 2.2.3 --- Cloning of zebrafish FSHR (zfFSHR) and LHR (zfLHR) cDNA fragments from the zebrafish ovary --- p.23 / Chapter 2.2.4 --- Rapid amplification of 5´ةcDNA ends (5'-RACE) and full-length cDNA --- p.24 / Chapter 2.2.5 --- Isolation of ovarian follicles --- p.25 / Chapter 2.2.6 --- Sampling of the ovaries from sexually immature zebrafish --- p.25 / Chapter 2.2.7 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.25 / Chapter 2.2.8 --- Construction of expression plasmids --- p.26 / Chapter 2.2.9 --- Transient transfection and reporter gene assay --- p.27 / Chapter 2.2.10 --- Establishment and characterization of stable zfFSHR or zfLHR-expressing cell lines --- p.28 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Cloning of FSHR and LHR cDNA from the zebrafish ovary --- p.29 / Chapter 2.3.2 --- Functional characterization of zfFSHR and zfLHR --- p.30 / Chapter 2.3.3 --- Expression of zfFSHR and zfLHR during sexual maturation --- p.31 / Chapter 2.3.4 --- Stage-dependent expression of zfFSHR and zfLHR in the ovarian follicles --- p.32 / Chapter 2.4 --- Discussion --- p.33 / Chapter Chapter 3 --- Down-regulation of FSHR and LHR Expression in the Zebrafish Follicle Ceils by Gonadotropin (hCG) and Its Sigaling Mechanism / Chapter 3.1 --- Introduction --- p.51 / Chapter 3.2 --- Materials and Methods / Chapter 3.2.1 --- Animals --- p.54 / Chapter 3.2.2 --- Chemicals and hormones --- p.54 / Chapter 3.2.3 --- Primary follicle cell culture --- p.55 / Chapter 3.2.4 --- Total RNA isolation --- p.55 / Chapter 3.2.5 --- "Validation of semi-quantitative RT-PCR assays for FSHR, LHR and GAPDH" --- p.56 / Chapter 3.2.6 --- Data analysis --- p.57 / Chapter 3.3 --- Results / Chapter 3.3.1 --- Validation of semi-quantitative RT-PCR assays --- p.57 / Chapter 3.3.2 --- Gonadotropin regulation of FSHR and LHR expression in cultured zebrafish ovarian follicle cells --- p.58 / Chapter 3.3.3 --- Effect of db-cAMP and forskolin on FSHR and LHR expression --- p.59 / Chapter 3.3.4 --- Effects of H89 on hCG-induced suppression of FSHR and LHR expression --- p.60 / Chapter 3.4 --- Discussion --- p.60 / Chapter Chapter 4 --- General Discussion --- p.75 / Chapter 4.1 --- Cloning of zebrafish FSHR and LHR cDNAs and demonstration of receptor specificity --- p.77 / Chapter 4.2 --- Evidence for the differential expression of FSHR and LHR in the zebrafish ovarian and follicle development --- p.78 / Chapter 4.3 --- Down-regulation of FSHR and LHR expression in the zebrafish follicle cells by gonadotropin (hCG) --- p.79 / Chapter 4.4 --- Future research direction --- p.80 / References --- p.84

So Wai-Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 100-127). / Abstracts in English and Chinese. / Acknowledgement --- p.I / Abstract (in English) --- p.II / Abstract (in Chinese) --- p.IV / Table of contents --- p.VI / List of Figures --- p.X / Symbols and Abbreviations --- p.XII / List of fish names mentioned in the thesis --- p.XIV / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Pituitary --- p.1 / Chapter 1.2 --- Gonadotropins --- p.1 / Chapter 1.2.1 --- Structure --- p.2 / Chapter 1.2.2 --- Signaling --- p.3 / Chapter 1.2.3 --- Expression --- p.5 / Chapter 1.2.4 --- Functions --- p.7 / Chapter 1.2.4.1 --- Gonadotropin actions on gametogenesis --- p.7 / Chapter 1.2.4.2 --- Gonadotropin actions on steroidogenesis --- p.8 / Chapter 1.2.5 --- Regulation --- p.9 / Chapter 1.2.5.1 --- Neuroendocrine control --- p.10 / Chapter 1.2.5.1.1 --- Gonadotropin-releasing hormone (GnRH) --- p.10 / Chapter 1.2.5.1.2 --- Dopamine (DA) --- p.12 / Chapter 1.2.5.2 --- Gonadal steroid feedback --- p.12 / Chapter 1.2.5.2.1 --- Positive feedback --- p.13 / Chapter 1.2.5.2.2 --- Negative feedback --- p.14 / Chapter 1.2.5.3 --- Paracrine regulators within pituitary --- p.15 / Chapter 1.3 --- Objectives of the present study --- p.16 / Chapter Chapter 2 --- "Molecular Cloning and Functional Characterization of Zebrafish FSHβ, LHβ and GTHα subunits" / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Materials and methods --- p.21 / Chapter 2.2.1 --- Chemicals --- p.21 / Chapter 2.2.2 --- Animals --- p.21 / Chapter 2.2.3 --- Genomic DNA isolation --- p.22 / Chapter 2.2.4 --- Total RNA isolation --- p.22 / Chapter 2.2.5 --- Cloning of zebrafish FSHp，LHβ and GTHa fragments --- p.23 / Chapter 2.2.5.1 --- LHβ and GTHα --- p.23 / Chapter 2.2.5.2 --- FSHβ --- p.23 / Chapter 2.2.6 --- "5'- and 3'-RACE of zebrafish FSHp, LHβ and GTHα subunits" --- p.24 / Chapter 2.2.7 --- Construction of expression constructs --- p.25 / Chapter 2.2.8 --- Cell culture and transfection of Flp-In´ёØ CHO cell --- p.26 / Chapter 2.2.9 --- Recombinant production of zebrafish FSH and LH --- p.27 / Chapter 2.2.10 --- Reverse transcription-polymerase chain reaction (RT-PCR) analysis --- p.27 / Chapter 2.2.11 --- Northern blot hybridization --- p.28 / Chapter 2.2.12 --- SEAP reporter gene assay --- p.28 / Chapter 2.2.13 --- Data analysis --- p.29 / Chapter 2.3 --- Results --- p.30 / Chapter 2.3.1 --- "Cloning of zebrafish FSHβ, LHβ and GTHα subunits" --- p.30 / Chapter 2.3.2 --- "Expression of zebrafish FSHp, LHβ and GTHα in the zebrafish pituitary" --- p.31 / Chapter 2.3.3 --- Recombinant production of zebrafish FSH and LH --- p.32 / Chapter 2.3.4 --- Functional analysis of zebrafish FSH and LH --- p.33 / Chapter 2.4 --- Discussion --- p.34 / Chapter Chapter 3 --- "Spatial Expression Patterns of Zebrafish FSHβ, LHβ and GTHα Subunits in the Pituitary and Their Temporal Expression Profiles during Sexual Maturation and Ovulatory Cycle" / Chapter 3.1 --- Introduction --- p.58 / Chapter 3.2 --- Materials and methods --- p.61 / Chapter 3.2.1 --- Chemicals --- p.61 / Chapter 3.2.2. --- Animals --- p.62 / Chapter 3.2.3 --- Total RNA isolation from zebrafish pituitaries and reverse transcription --- p.62 / Chapter 3.2.4 --- Validation of RT-PCR on single pituitary --- p.63 / Chapter 3.2.5 --- Real-time PCR --- p.64 / Chapter 3.2.6 --- Tissue preparation for in situ hybridization --- p.64 / Chapter 3.2.7 --- In situ hybridization --- p.65 / Chapter 3.2.8 --- Data analysis --- p.66 / Chapter 3.3 --- Results --- p.66 / Chapter 3.3.1 --- "PCR amplification of FSHβ, LHβ and GTHα and GAPDH in single zebrafish pituitary" --- p.67 / Chapter 3.3.2 --- "Establishement of real-time RT-PCR for zebrafish FSHβ, LHβ and GTHa and GAPDH" --- p.67 / Chapter 3.3.3 --- "Temporal expression profiles of zebrafish FSHβ, LHβ and GTHα subunits during sexual maturation" --- p.67 / Chapter 3.3.4 --- "Temporal expression profiles of zebrafish FSHp, LHβ and GTHα subunits during ovulatory cycle" --- p.68 / Chapter 3.3.5 --- "In situ hybridization of zebrafish FSHβ, LHβ and GTHα" --- p.69 / Chapter 3.4 --- Discussion --- p.70 / Chapter Chapter 4 --- General Discussion / Chapter 4.1 --- Cloning of zebrafish gonadotropin subunit cDNAs --- p.91 / Chapter 4.2 --- Bioactivity and receptor specificity of recombinant zebrafish FSH and LH --- p.91 / Chapter 4.3 --- Expression of gonadotropin subunits during zebrafish sexual maturation and ovulatory cycle --- p.92 / Chapter 4.4 --- "Localization of FSHβ, LHβ and GTHα subunits in zebrafish pituitary" --- p.93 / Chapter 4.5 --- Contributions of the present study --- p.94 / Chapter 4.6 --- Future prospects --- p.95 / References --- p.100

To produce male Muscovy only for fatty liver and meat-type production is an important economic goal in animal husbandry, although the sex-determining mechanism in poultry remains to be elucidated. Manipulation of sex-determining gene(s) in poultry provides enormous opportunities on the development of sex pre-selection reproductive systems. DSX and MAB-3 genes in Drosophila and C. elegans are conserved across the human, mice, chickens, fish, turtles, and reptiles revealing an ancient sex-determining locus DMRT1. Thus the Z-linked, DMRT1 in chicken is an excellent candidate regulatory gene controlling similar aspects of sexual development in poultry. This dissertation is aimed to clone and characterize Muscovy DMRT1 gene for further application in sex pre-selection. Partial cDNA sequences of Muscovy DMRT1 was determined and revealed 95% identity and 83% with chicken and red-eared slider turtle DMRT1 cDNA sequences. DMRT1 orthologs among various species were analyzed by Phylip program and phylogenetic tree was constructed by MEGA2 programs. Results indicated that Muscovy, chicken and red-eared slider turtle DMRT1 revealing 95%, and 83% identity at cDNA and 61%, 54% identity at amino acid level.

Ornithine decarboxylase (ODC) is the rate determining enzyme in the biosynthesis of polyamines which are essential for cell growth. In chickens, significantly higher bioactivity is reported in broiler than in egg layer strains of chickens (Bulfield et al., 1988). To characterize the genetic differences in growth rates and ODC levels in chickens, an ODC cDNA and genomic gene were cloned and sequenced. Sequencing of ODC cDNA revealed that this clone (pODZ3: 2,052 bp) was not a full length of ODC cDNA and contained 2 putative introns. The open reading frame (introns deleted) coded for a protein of 404 amino acids which had about 85% amino acid identity with human ODC. Sequencing of genomic ODC clone (pODG2-8: 5098 bp) represented the 3$ prime$ end of ODC gene from downstream of intron 7. Northern blotting of chicken RNA probed with the insert of pODZ3 revealed 2 hybridizable messages of 1.6 and 2.1 kb, respectively. In addition, analysis of MspI restriction fragment length polymorphism (RFLP) using the 3$ prime$ end of ODC gene as a probe suggested that two MspI RFLPs present in the lean line of broiler chickens was related to selection of high lean body mass.

In addition to substrate-associated cellulases, Cellulomonas fimi secretes endoglucanases ( endo-1, 4-β-D-glucan glucanohydrolases, EC 3.2.1.4. ) which are recovered from the cellulose-free culture supernatant of cells grown on microcrystalline cellulose. Two such enzymes, C3.1 and C3.2 with Mrs of 130'000 and 120'000, respectively, were purified to homogeneity. The two endoglucanases were shown to share the same N-terminal amino acid sequence and to hydrolyze carboxymethylcellulose ( CMC ) with similar efficiencies ( 236u/mg protein for C3.1 and 367u/mg protein for C3.2 ). The recombinant lambda vector L47.1-169 was identified from a C.fimi DNA-lambda library on the basis of hybridization with C3.1/2-specific oligonucleotide probes. The subclone pTZ18R-8 only moderately expressed CMCase activity. The 5'-terminus of cenC ( the gene coding for C3.1/2 ) was localized in the insert by Southern transfer experiments and nucleotide sequence analysis. Results from total C.fimi RNA-DNA hybrid protection analyses defined the boundaries of cenC in pTZ18R-8 and led to the tentative identification of -10 and -35 promoter sequences. To improve the expression of cenC, its entire coding sequence, except for the start codon GTG, was fused in frame to the ATG codon of a synthetic ribosomal binding site ( PTIS ) and placed under the transcriptional control of the lac p/o system. Induction of the resulting clone ( JM101[pTZP-cenC] ) led to impaired growth in liquid cultures because overproduction of CenC inhibited cell division'" and eventually led to cell death. Analysis of cell fractions by SDS-PAGE revealed a dominant ( >10% of total cell extract proteins ), clone-specific protein with a Mr of approximately 140'000 which was found exclusively in the cytoplasmic fraction. Conversely, 60% of the total CMC-hydrolyzing activity was localized in the periplasmic fraction indicating that the export of CenC is required for maximal expression of endoglucanase activity. Isolation of the cellulolytic activities from an osmotic shockate led to the purification to homogeneity of two recombinant cellulases, CenC1 and CenC2, with Mr of 130'000 and 120'000, respectively. Both enzymes hydrolyzed CMC with similar efficiencies ( 278u/mg protein for CenC1 and 390u/mg protein for CenC2 ). In addition, amino acid sequence analyses showed the two enzymes to have the same N-termini as the native enzymes and proved furthermore that the CenC leader peptide was functional in Escherichia coli. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate