The genus Gluconobacter consists of acetic acid bacteria which have the ability to generate acidic products from their substrates, particularly acetic acid from ethanol. For this reason, the gluconobacters live in acidic, sugary environments such as flowers, honey bees, fruits, cider, vinegar, wine and beer. The gluconobacters carry out a strictly respiratory type of metabolism using only oxygen as a terminal electron acceptor. They do not completely oxidize a substrate to carbon dioxide. Instead, they partially oxidize the substrate using membrane-bound dehydrogenases and excrete the product into the surrounding growth medium. It is these limited oxidations that make the gtuconobacters industrially useful. Although much is known about the physiology of the limited oxidations in the gluconobacters, little is known of their genetics, particularly, their plasmids. The overall purpose of this dissertation was to determine if Gluconobacter plasmids correlate with oxidative capability and/or antibiotic resistance. To achieve this goal, I first needed a way to screen strains of Gluconobacter for their ability to oxidize many different substrates. 'developed an assay that used an unusual artificial electron acceptor, tetranitroblue tetrazolium (TNBT) and then tested the ability of six strains to oxidize 13 chemical compounds. Although most strains were able to oxidize the 13 compounds tested, they accomplished this with varying extents of oxidation. These differences were noted even with strains representing the same species. / Ph. D.

The present study investigated the effects of suggested analgesia and level of hypnotic susceptibility (high vs. low) on acute radiant heat pain using a signal detection theory model. A signal detection paradigm was used in order to differentiate between sensitivity (sensory-discriminative) and respose bias (motivational-affective) components of pain. Treatments consisted of: (1) a suggested analgesia group, and (2) an expectancy control group. Both groups had equal numbers of high and low scorers on a scale of hypnotic susceptibility. Subjects were 32 male and female undergraduate volunteers assigned equally to each of the two treatment groups and counterbalanced for level of hypnotic susceptibility. Five levels of radiant heat (including zero) were presented. Each subject received 30 stimulus presentations per level and rated each stimulus on a scale from zero to six, with seven being a withdrawal. Self-report inventories of trait and state anxiety were also taken. Subjects participated in pre- and posttreatment sessions of radiant heat stimulation and were given three training sessions in the interim. Results were that sensitivity measures showed a significant decrease for the suggested analgesia group for all but the highest stimulus level paired comparison. There was also a decrease in sensitivity for the expectancy control group for the lowest stimulus pair. Measures of response bias for a report of pain or higher changed nondifferentially across groups and levels, except for the highest stimulus pair, for which the experimental group showed a significant hesitancy to respond relative to the control group. There were no significant difference in terms of treatment effects for high vs. low hypnotic susceptibility. Mean pain ratings decreased for both groups. Trait anxiety did not but state anxiety did decrease significantly after treatment. Results were taken as supporting Gate Control Theory and a figure-ground realignment model of pain. Suggestions were made for directions in future research. / Doctor of Philosophy

Annual bluegrass weevil (Listronotus maculicollis Kirby) (Coleoptera: Curculionidae) (ABW) is a major pest of annual bluegrass (Poa annua L.) and creeping bentgrass (Agrostis stolonifera L.) on golf courses in the northeastern United States. The asynchronous life cycle makes managing ABW difficult, putting emphasis on scouting to achieve accurate insecticide timing and acceptable control. Little is known about the biology and management of ABW in Virginia's more temperate climate. Reported cases of ABW resistance to pyrethroids (IRAC Group 3) continues to grow in the northeast, yet no pyrethroid-resistance cases have been reported in Virginia outside of the metropolitan Washington, D.C. For this thesis, I confirmed the widespread distribution of ABW across Virginia with a survey of golf course superintendents. Two golf courses in southwestern Virginia were monitored weekly during the 2019 and 2020 growing seasons to determine the seasonal biology of ABW within this region. These data suggest that overwintering ABW emerge much earlier than described in the northeast, with adult weevil activity beginning in late February or early March. I observed three complete ABW generations, with a potential fourth generation. Soil plugs from the same two golf courses were used to compare the salt floatation and Berlese-Tullgren funnel methods of larval extraction. The methods were highly correlated (R2 = 0.7856), suggesting either method is appropriate for ABW larval extraction. Bioassays conducted on adult ABW from the same two golf courses showed that field rate concentrations of the pyrethroid bifenthrin showed variable mortality ranging from 20% to 80% suggesting the presence of resistance genes in the population. A 100-fold rate of bifenthrin resulted in 100% mortality of ABW, however. Because cross-resistance has been reported among northeastern ABW populations, the common insecticide active ingredients chlorpyrifos (IRAC Group 1B: Organophosphate), trichlorfon (IRAC Group 1B: Organophosphate), λ-cyhalothrin (IRAC Group 3: Pyrethroid), α-cypermethrin (IRAC Group 3: Pyrethroid), imidacloprid (IRAC Group 4A: Neonicotinoid), and spinosad (IRAC Group 5: Spinosyn), were tested on ABW adults. In another bioassay, two organophosphates, trichlorfon and chlorpyrifos, resulted in significantly higher ABW mortality rates than all other labeled insecticides (P < 0.0001). Two other larvicides, spinosad and α-cypermethrin, also exhibited adult control, an important factor to consider for ABW management and preventing pyrethroid-resistance. These results provide valuable insight into the seasonal biology and management of ABW in Virginia and direction for further investigation into these populations. / Master of Science in Life Sciences / Annual bluegrass weevil (Listronotus maculicollis Kirby) (ABW) is a tiny, but damaging insect pest of cool-season golf course turfgrasses in the northeastern United States. As pest populations have spread southward, ABW has become an emerging pest in Virginia. The objectives of this thesis were to 1) determine the geographic distribution and seasonal biology of ABW in Virginia, 2) compare two methods for extracting ABW larvae from turf cores in order to estimate larval densities, and 3) to assess the susceptibility of ABW to various insecticides commonly used by golf course superintendents. A survey of golf course superintendents in 2019 revealed widespread prevalence of ABW across Virginia, particularly in areas growing predominantly cool-season turfgrasses. Two golf courses in southwestern Virginia were monitored weekly during the growing seasons of 2019 and 2020 to determine the seasonal biology of ABW. Data suggest that overwintering ABW emerge much earlier than reported in the northeast, with adult weevil activity beginning in late February or early March compared to April in the northeast. In addition, I detected three complete ABW generations, with a possible fourth generation occurring. Soil plugs from two golf courses were used to compare a heat extraction method using a Berlese-Tullgren funnel with the traditional salt float method for extraction of ABW larvae. The two methods extracted similar numbers of ABW larvae suggesting that either method is appropriate for ABW larval extraction. Adult ABW from the same two golf courses were collected and subjected to the pyrethroid insecticide bifenthrin at 0.128 kg ai ha-1 (field application rate), 1.28 kg ai ha-1 (10-fold rate), 12.8 kg ai ha-1 (100-fold rate), along with a water control. Results indicated that the field application rate of bifenthrin killed > 50% but <90% of ABW adults, suggesting that some resistance may be present in the population. A concentration of 100-fold bifenthrin field rate killed 100% of tested individuals, suggesting that widescale field resistance to pyrethroids is likely not present. Because cross-resistance has been reported among northeastern ABW populations, the common insecticide active ingredients chlorpyrifos (IRAC Group 1B: Organophosphate), trichlorfon (IRAC Group 1B: Organophosphate), λ-cyhalothrin (IRAC Group 3: Pyrethroid), α-cypermethrin (IRAC Group 3: Pyrethroid), imidacloprid (IRAC Group 4A: Neonicotinoid), and spinosad (IRAC Group 5: Spinosyn), were tested on ABW adults from the same two golf courses. Two organophosphates, trichlorfon, a larvicide, and chlorpyrifos resulted in significantly higher ABW mortality rates than all other active ingredients (P < 0.0001). Two other larvicides, spinosad and α-cypermethrin, also exhibited adult control, an important factor to consider when attempting to manage ABW and preventing resistance to pyrethroids. Our results provide valuable insight into the seasonal biology and management of ABW in Virginia and direction for further investigation into these populations.

Mycobacterium avium and Mycobacterium intracellulare are environmental opportunistic pathogens whose source for human infection is water and soil. M. avium and M. intracellulare cause pulmonary infections (tuberculosis) in immunocompetent individuals and bacteremia in immunodeficient individuals (e.g. AIDS). One factor likely influencing the lack of success of antibiotic therapy in patients would be their ability to form biofilms. Growth in biofilms might result in antimicrobial resistance because (1) cells are protected by layers of other cells and extracellular material (2) and differences in physiologic state of cells as a consequence of growing on surfaces. The objectives of the work were to (1) establish methods for reproducible growth of mycobacterial biofilms (2) measure the formation of biofilms on surfaces by cells of M. avium and M. intracellulare (3) measure the antibiotic- and chlorine- susceptibility of M. avium and M. intracellulare strain TMC1406T in cell grown in suspension, cells grown in biofilms and suspended and of cells grown in biofilms (4) measure the hydrophobicity of M. avium and M. intracellulare grown in suspension and in biofilms. Methods were developed for growing mycobacteria in biofilms in polystyrene flasks and on glass beads. Although both strains formed biofilms, M. intracellulare strain TMC 1406T more readily formed biofilms than M. avium strain A5 in polystyrene flasks. The majority of M. intracellulare strain TMC 1406T cells grew on the walls of the flasks rather than in suspension like M. avium strain A5. The susceptibility of M7H9 medium-grown cells of M. avium strain A5 and M. intracellulare strain TMC 1406T cells grown in suspension, cells grown in biofilms and suspended and cells grown in biofilms was measured against clarithromycin, ethambutol, kanamycin, rifampicin and streptomycin. Cells grown in biofilms and exposed to antibiotics in biofilms were five-fold resistant to antibiotics than were cells grown in biofilms and exposed in suspension. Cells grown and exposed in suspension were ten-fold more sensitive to antibiotics than were cells grown in biofilms and exposed in suspension. The chlorine susceptibility of cells grown in medium and water was also measured. Cells grown in biofilms were more resistant to chlorine than cells grown in biofilms and suspended. Cells grown in suspension were more sensitive to chlorine than cells grown in biofilms and suspended. The hydrophobicity data (i.e., hexadecane adherence and contact angle measurements) showed that cells grown in biofilms are more hydrophobic than cells grown in biofilms and suspended and cells grown in suspension. It is clear that there are physiological changes between cells grown in suspension, cells grown in biofilms and suspended and cells in biofilms. / Master of Science

No / Lymphocyte responses from 208 individuals: 20 with melanoma, 34 with colon cancer, and 4 with lung cancer (58), 18 with suspected melanoma, 28 with polyposis, and 10 with COPD (56), and 94 healthy volunteers were examined. The natural logarithm of the Olive tail moment (OTM) was plotted for exposure to UVA through 5 different agar depths (100 cell measurements/depth) and analyzed using a repeated measures regression model. Responses of patients with cancer plateaued after treatment with different UVA intensities, but returned toward control values for healthy volunteers. For precancerous conditions and suspected cancers, intermediate responses occurred. ROC analysis of mean log OTMs, for cancers plus precancerous/suspect conditions vs. controls, cancer vs. precancerous/suspect conditions plus controls, and cancer vs. controls, gave areas under the curve of 0.87, 0.89, and 0.93, respectively (P<0.001). Optimization allowed test sensitivity or specificity to approach 100% with acceptable complementary measures. This modified comet assay could represent a stand-alone test or an adjunct to other investigative procedures for detecting cancer.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Tuberculosis (TB) disease results in approximately 2 million deaths annually and is the leading cause of death due to a single infectious agent. Previous studies have indicated that host genetics play an important role in the development of TB. This together with pathogen and environmental factors intensifies the complexity of this disease. The Major Histocompatibility Complex (MHC) and Leukocyte Receptor Complex (LRC) comprise several genes which are known to be important modulators of the host immune response. The human leukocyte antigen (HLA) class-I genes of the MHC are involved in the presentation of pathogenic antigens on the surfaces of infected cells, while the killer cell immunoglobulin-like receptors (KIRs) of the LRC are involved in the recognition of self and non-self cells. Natural Killer (NK) cells through their KIRs are thus able to kill non-self cells through recognition of the class-I molecules expressed. Additionally, HLAs and KIRs are extremely polymorphic and differ markedly across populations of different ethnicities. Here we studied these genes and their polymorphisms in the South African Coloured (SAC) population to determine their involvement in susceptibility to TB, susceptibility to disease caused by specific Mycobacterium tuberculosis subtypes, and understanding their ancestral contribution to the SAC with regards to the development of TB. We showed that the KIR3DS1 gene and KIR genotypes with five or more activating KIRs, and the presence of 3DS1, protected against the development of active TB in the SAC population. Several HLA class-I alleles were identified as susceptibility factors for TB disease. With regards to genes of the MHC and LRC, several loci were found to alter susceptibility to TB in the SAC population, including MDC1, BTNL2, HLA-DOA, HLA-DOB, C6orf10, TAP2, LILRA5, NCR1, NLRP7 and the intergenic regions between HLA-C/WASF5P and LAIR1/TTYH1. We showed that the Beijing strain occurred more frequently in individuals with multiple disease episodes, with the HLA-B27 allele lowering the odds of having an additional episode. Associations were identified for specific HLA types and disease caused by the Beijing, Latin America-Mediterranean (LAM), Low-Copy Clade (LCC), and Quebec strains. HLA types were associated with disease caused by strains from the Euro-American or East Asian lineages, and the frequencies of these alleles in their sympatric human populations identified potential co-evolutionary events between host and pathogen. Finally, we showed that the SAC population is the most diverse SA population with regards to HLA alleles and KIR genotypes, as would be expected given the admixture of the SAC. Based on the HLA allele class-I profiles across SA populations, we noted that the Ag85BESAT- 6, Ag85B-TB10.4 and Mtb72f vaccines currently undergoing clinical trials would have low efficacy across most SA populations. We showed that the MHC and LRC regions in SAC healthy controls are predominantly of European ancestry, and that SAC TB cases are more closely related to Khoisan and black SA population groups. Our work highlights the importance of investigating both host and pathogen genetics when studying TB disease development and that understanding the genetic ancestral contributions to the SAC population can contribute to the identification of true and novel TB causing variants. / AFRIKAANSE OPSOMMING: Tuberkulose (TB) is jaarliks verantwoordelik vir ongeveer 2 miljoen sterftes en is die hoofoorsaak van dood as gevolg van „n aansteeklike siekte. Vorige navorsingstudies het aangedui dat die genetiese samestelling van die gasheer „n beduidende rol speel in die ontwikkeling van TB. Die kompleksiteit van hierdie siekte word vererger deur die betrokkenheid van die gasheer genoom sowel as bakteriële en omgewings faktore. Die Major Histocompatibility Complex (MHC) en Leukocyte Receptor Complex (LRC) bestaan uit verskeie gene wat die gasheer immuunrespons verstel. Die human leukocyte antigen (HLA) klas I gene van die MHC is betrokke by die aanbieding van patogeniese antigene op die oppervlak van geïnfekteerde selle, terwyl die killer cell immunoglobulin-like receptors (KIRs), geleë in die LRC, betrokke is by die herkenning van eie en vreemde selle. NK selle, deur middel van hul KIRs, kan dus vreemde selle uitwis aangesien hulle die uitgedrukte klas I molekules kan herken. Beide HLA en KIRs is hoogs polimorfies en verskil beduidend tussen etniese groepe. In hierdie studie is die bogenoemde gene en hul polimorfismes in die Suid Afrikaanse Kleurling bevolking (SAC) ondersoek om vas te stel tot watter mate dit genetiese vatbaarheid vir TB, asook vatbaarheid vir TB wat deur spesifieke Mycobacterium tuberculosis subtipes veroorsaak word, beïnvloed. Daar is ook gepoog om te verstaan hoe die voorouerlike bydrae van hierdie gene die SAC met betrekking tot TB vatbaarheid affekteer. Die resultate van die studie het aangedui dat die KIR3DS1 geen en KIR genotipes met vyf of meer aktiewe KIRs en die teenwoordigheid van 3DS1, die SAC bevolking beskerm teen die ontwikkeling van aktiewe TB. Verskeie HLA klas I allele is geïdentifiseer as vatbaarheidsfaktore vir TB. Talle lokusse van die MHC en LRC gene is ook as vatbaarheidsfaktore vir TB in die SAC bevolking geïdentifiseer, insluitende MDC1, BTNL2, HLA-DOA, HLA-DOB, C6orf10, TAP2, LILRA5, NCR1, NLRP7 en die intergeniese areas tussen HLA-C/WASF5P en LAIR1/TTYH1. Die studie het aangedui dat die Beijing stam meer voorkom in individue wat verskeie kere TB gehad het en dat die HLA-B27 alleel die kanse om „n verdere episode te hê, verlaag het. Assosiasies is geïdentifiseer tussen spesifieke HLA tipes en siekte veroorsaak deur die Beijing, LAM, LCC, en Quebec TB stamme. HLA tipes was geassosieer met siekte veroorsaak deur TB stamme van Euro-Amerikaanse en Oos-Asiëse afkoms. Die frekwensies van hierdie allele, in hul ooreenstemmende mensbevolkings, dui op „n potensïele koevolusionêre gebeurtenis tussen die gasheer en patogeen. Die studie het ook vasgestel dat die SAC populasie die mees diverse SA bevolking is met betrekking tot die HLA allele en KIR genotipes, soos verwag sou word gegewe die gemengde genetiese herkoms van die SAC. Gebaseer op die HLA allele klas I profiel van verskillende SA bevolkings merk ons op dat die Ag85B-ESAT-6, Ag85B-TB10.4 en Mtb72f vaksiene, wat huidiglik kliniese toetsing ondergaan, nie so effektief in die meeste SA bevolkings sal wees nie. Die studie het ook bewys dat die MHC en LRC streke in gesonde SAC kontroles, grootliks afkomstig was van „n Europese nalatenskap en dat die SAC TB gevalle meer verwant is aan die Khoisan en swart SA bevolkings. Hierdie studie beklemtoon die noodsaaklikheid om beide gasheer en patogeen genetika te bestudeer wanneer die ontwikkeling van TB ondersoek word en dat die verstaan van die genetiese voorouerlike bydrae van die SAC bevolking kan bydra tot die identifisering van ware en nuwe TB-veroorsakende variante.

La gestion de Phytophthora infestans, agent du mildiou de la pomme de terre, nécessite l’application d’une quinzaine de traitements par saison culturale. Pour réduire l’usage des fongicides, combiner résistance induite et résistance quantitative pourrait être une bonne stratégie. Elle nécessite cependant une meilleure connaissance des interactions entre les réponses physiologiques de Solanum tuberosum et l’écologie de P. infestans. Dans cet objectif, les réponses de défense induites chez la pomme de terre ont été confrontées aux traits d’histoire de vie et effecteurs de P. infestans. Quatre génotypes présentant différents niveaux de résistance ont été traités avec un filtrat de culture concentré (CCF) de P. infestans induisant la PAMP-triggered immunity (PTI). Des folioles détachées ont ensuite été inoculées avec des souches rapides ou lentes de P. infestans. Les expressions de 14 gènes de défense et de 6 effecteurs ont été analysée simultanément par qRT-PCR.Les symptômes de la maladie ont été mesurés classiquement ou par analyse d’images dans le visible et en fluorescence. Les résultats obtenus montrent que la réduction des symptômes après induction de la PTI est fonction du couple génotype-souche. En effet, l’efficacité des défenses induites par le CCF dépend des stratégies d’échappement (vitesse de croissance) ou d’adaptation (effecteurs) de P. infestans et du potentiel d’inductibilité du génotype (expression des protéines PR). Ainsi, pour optimiser l’utilisation de la résistante induite il serait nécessaire de sélectionner des génotypes inductibles et capables de modu / The management of Phytophthora infestans, responsible for potato late blight, requires the application of about 15 fungicide treatments per cropping season. To reduce the use of pesticides, combining induced resistance and quantitative resistance could be a positive strategy. However, this method requires a better understanding of the interactions between Solanum tuberosum physiological responses and P. infestans ecology. To this end, defense responses induced in potato have been opposed to the pathogen life history traits and effectors. Four potato genotypes with different resistance levels were treated with a concentrated culture filtrate (CCF) of P. infestans inducing PAMPtriggered immunity (PTI). Then, detached leaflets were inoculated with fast- or slow-growing strains of P. infestans.The expression of 14 defense genes and the expression of 6 effectors were analyzed simultaneously by qRT-PCR. Disease symptoms were measured either conventionally or by visible and fluorescence image analysis. The results obtained show that the reduction of symptoms after induction of PTI was specific to the genotype-strain pair. Indeed, the effectiveness of induced defenses by CCF depends on either the escape (growth rate) or adaptation (effectors) strategies of P. infestans and on the genotype inductibility potential (expression of PR proteins). Thus, to optimize the use of induced resistance, it would be necessary to breed inducible genotypes that are able to modulate strains growth rate.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2013-10-18T17:47:47Z No. of bitstreams: 1 Danniel Sann Dias da Silva Analise da ancestralidade...2013.pdf: 1290114 bytes, checksum: 95da03014304e202e3b248867ec987a7 (MD5) / Made available in DSpace on 2013-10-18T17:47:47Z (GMT). No. of bitstreams: 1 Danniel Sann Dias da Silva Analise da ancestralidade...2013.pdf: 1290114 bytes, checksum: 95da03014304e202e3b248867ec987a7 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / O carcinoma escamocelular oral (CEO), entre homens, é o quarto câncer mais frequente no Nordeste do Brasil e o terceiro na Bahia. Apesar de possuir etiologia multifatorial, pelo menos 80% dos casos são atribuíveis à exposição ao fumo e ao álcool. Suscetibilidade individual ao CEO tem sido amplamente estudada, e é atribuída a fatores genéticos e também sócio-econômicos. Polimorfismos genéticos de risco, comuns em determinadas populações; hábitos de vida; dificuldade de acesso à informação e aos serviços de saúde são exemplos destes fatores. Sabendo da alta incidência do CEO na Bahia objetivou-se analisar a distribuição dos fatores de risco para CEO numa amostra da população da Bahia. Participaram 332 doadores voluntários de um banco de sangue público baiano, com idade entre 19 e 66 anos. Coletaram-se amostras biológicas de 320 indivíduos e aplicou-se questionário epidemiológico em 309. Investigaram-se cinco polimorfismos de risco (GSTT1*nulo, GSTM1*nulo, CYP1A1*2C (rs1048943), XRCC1 399*Gln (rs25487) eXRCC1 194*Trp (rs1799782) e nove marcadores informativos de ancestralidade (AIMs), por meio de PCR para as inserções e/ou deleções, e PCR-RFLP ou Real Time-PCR para as mutações pontuais. Observou-se presença dos alelos de risco variando entre 12,3% e 56,5% dos indivíduos (XRCC1 194*Trp e XRCC1 399*Gln, respectivamente). A frequência do tabagismo foi 14,6%, etilismo 64,3% (12,7% azem uso abusivo de álcool). Os outros fatores de risco variaram entre 2,3% e 1,3% (relato de HPV e dificuldades de acesso aos serviços de saúde). A estimativa de ancestralidade mostrou maior contribuição ancestral nativo americana em portadores do genótipo GSTM1-nulo que nos não-nulo, o qual foi mais frequente em brancos. Não foi observada associação entre ancestralidade/raça e os fatores de risco ambientais. No entanto, alguns fatores de risco foram associados à baixa renda, e, principalmente, à baixa escolaridade. Contudo, embora a ancestralidade possa influenciar a suscetibilidade genética, não houve influência sobre a suscetibilidade ambiental já que os fatores de risco ambientais se relacionaram principalmente com aspectos socioeconômicos. / The oral squamous cell carcinomas (CEO) is the fourth most common cancer in northeastern Brazil and also in Bahia. Despite having a multifactorial etiology, at least 80% of cases are attributable to exposure to tobacco and alcohol. Individual susceptibility to CEO has been widely studied, and is attributed to genetic and socioeconomic factors. Genetic polymorphisms of risk, common in certain ancestral populations; lifestyle; information access and health services difficulty are examples of such factors. Given the high incidence of CEO in Bahia we investigated the distribution of risk factors for CEO in a sample from Bahia population. Participated in 332 voluntary blood donors of a public blood bank in Bahia, ages ranged from 20 to 66 years. Biological samples was collect from 320 individuals and epidemiological questionnaire was applied to 309. We investigated five polymorphisms of susceptibility (GSTT1*null, GSTM1*null, CYP1A1*2C (rs1048943), XRCC1 399*Gln (rs25487) and XRCC1 194*Trp (rs1799782)) and nine ancestry informative markers (AIMs) by PCR for insertions and/or deletions, and PCR-RFLP and Real Time-PCR for SNP. We observed the presence of risk alleles ranging from 12.3% to 56.5% of subjects (XRCC1 194*Trp and XRCC1-399*Gln, respectively). Smoking was prevalent in 14.6% of subjects, alcoholism in 64.3% (12.7% alcohol abuse). The other risk factors varied between 2.3% and 41.3% (reported HPV and poor access to health services). The ancestry estimative showed high contribution of Native American in individuals with genotype GSTM1*null, which was more common in whites. In this sample, there was no relationship between ancestry/race and environmental risk factors. However, some risk factors were associated with low income, and, especially, low schooling. However, while the ancestry can influence genetic susceptibility, no influence on the environmental susceptibility, which relates mainly to socioeconomic factors.

ENGLISH ABSTRACT We present new results of structural and magnetic (AMS) analyses of selected dikes of melasyenite, quartz melasyenite to melagranite porphyries accompanied by lamprophyres (minettes). The studied dike from the locality Nihošovice were dated by U-Pb method on zircons at 338 Ma. The asymmetric structural pattern of the studied dikes gives an excellent evidence for their emplacement and orientation of magmatic flow. The studied dikes were emplaced into: (i) Prevailing parts of the Central Bohemian Plutonic Complex (locality Malčice) and (ii) host high-grade metamorphic rocks of western part of the Moldanubian Zone (locality Nihošovice). Despite of the extensive area of occurrence, compositional variations and age of emplacement of these dikes are relatively narrow. Their geochemical and petrological compositions broadly correspond to ultrapotassic plutonic rocks (durbachites). The dikes are steeply dipping in trend ~NNW-SSE to ~W-E, with range in width between ~20 and ~25 meters. In general, our results show: (i) A relatively low degree of magnetic anisotropy (P= 1.012 - 1.152); (ii) Mostly oblate (planar) fabric, especially in marginal parts of the intrusive bodies (T= -0.091 - 0.941); (iii) Evidence for subhorizontal magmatic flow trajectory defined for a newtonian magma with typical...

<p>MR phase images contain essential information about local magnetic susceptibility sources in the brain, creating a new type of contrast in magnetic resonance imaging (MRI). The goal of this thesis is to demonstrate with a model of the brain how accurately the transformation of phase to susceptibility takes place.</p> <p>A 3D brain model uses the Forward process to calculate magnetic field perturbations caused by susceptibility properties of the tissues in the model. Homodyne High Pass (HP) filter and SHARP algorithm are used to process the simulated phase images. Similarly, MR magnitude data are simulated using tissue properties such as T₁, T₂^* relaxation times and spin density.</p> <p>The halo ring around red nucleus in the real phase data is believed to be an indicator of a capsule around red nucleus. Similar effect is seen in the simulated phase images without including the capsule of red nucleus in the model, this comparison explains that the halo effect may just be entirely or a part of the phase behavior around red nucleus. A negative susceptibility in the internal capsule region, seen in both simulated and real susceptibility maps, is discussed as a possible artifact caused by the processing techniques after comparing the simulated susceptibility maps produced from unprocessed and processed phase data. The brain model is used to determine the optimum echo time of the initial gradient echo sequence in order to produce a high quality susceptibility map with reasonably low error and better time efficiency.</p> / Master of Applied Science (MASc)