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Étude moléculaire du recrutement des gènes de résistance aux antibiotiquesTremblay, Simon 12 April 2018 (has links)
Les séquences d'insertion sont des parasites moléculaires d'ADN codant uniquement pour leur machinerie de transposition et sont retrouvées majoritairement dans les génomes et les plasmides des procaryotes. Le séquençage génomique massif de la dernière décennie nous a permis de détecter chez des souches bactériennes cliniques plusieurs gènes de résistance aux antibiotiques associés aux séquences d'insertion sous forme de transposons composés. Il a été suggéré que les séquences d'insertion jouent un rôle prépondérant dans l'évolution bactérienne et qu'elles possèdent un pouvoir recruteur permettant de sélectionner, réorganiser et propager des gènes conférant un avantage sélectif à l'hôte. Nous avons partiellement caractérisé le potentiel recruteur de deux séquences d'insertion associées à des gènes de résistance, la séquence IS26 de Proteus vulgaris et la séquence ISJO de Salmonella typhimurium, en observant les étapes de recrutement d'un gène chromosomique et leurs distributions épidémiologiques en consultant les banques de données. / Insertion sequences are DNA molecular parasites encoding exclusively their transposition function, and are mainly found within the genomes and plasmids of prokaryotic organisms. The massive genomic sequencing we have witnessed in the last decade has allowed us to detect in clinical bacterial isolates many antibiotic resistance genes associated with insertion sequences in the form of composite transposons. It has been suggested that insertion sequences may act as a primary modulator of bacterial evolution, and that they possess a recruitment capacity allowing them to select, reorganize and spread genes encoding adaptation functions for their hosts. We have partially characterized the recruitment potential of two insertion sequences well known for their association with antibiotic resistance genes, IS10 from Salmonella typhimurium and 1S26 from Proteus vulgaris, by observing the steps involved in the recruitment process of a chromosomal gene and their epidemiological distribution by consulting various databanks.
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Les ilôts de résistance de type SGI1 (Salmonella Genomic Island 1) et apparentés dans des souches humaines cliniques de Porteus mirabilis et Salmonella enterica / Salmonella Genomic Island 1 (SGI1) and relative genomic islands from clinical Proteus mirabilis and Salmonella enterica isolatesGoulard de Curraize, Claire 01 December 2017 (has links)
Salmonella genomic island 1 (SGI1) est un élément intégratif mobilisable décrit pour la 1ère fois dans un clone penta-résistant de Salmonella Typhimurium DT104. Depuis, plusieurs variants et îlots apparentés (Proteus genomic island 1 (PGI1)) ont été rapportés dans différents sérotypes de Salmonella enterica et chez Proteus mirabilis. Ces îlots de résistance sont constitués d’un squelette plutôt stable et d’une région de multirésistance (MDR) variable. L’objectif de cette thèse était d’étudier ces îlots dans des souches cliniques de P. mirabilis (CHU de Dijon et Lariboisière à Paris) et de S. enterica (CHU de Dijon). La prévalence de ces îlots variait de 5 à 16% chez P. mirabilis ayant acquis au moins une résistance. L’étude génotypique a montré une grande diversité des souches mais également la présence de quelques clones porteurs de SGI1 ou PGI1. Le séquençage de ces îlots a mis en évidence la grande plasticité des régions MDR souvent en lien avec des mouvements d’IS26. Ces dernières permettent à la région MDR de s’enrichir en nouveaux gènes de résistance (ex : blaCTX-M-15) présents dans des structures antérieurement décrites sur des plasmides de clones d’entérobactéries répandus. De nombreuses espèces d’entérobactéries porteuses d’un plasmide IncA/C sont capables d’acquérir par conjugaison un îlot provenant d’une autre entérobactérie. Cet îlot s’intègre alors au niveau du site chromosomique spécifique (trmE). Sous pression antibiotique et en présence d’un plasmide IncA/C, les souches peuvent être complètement excisées de leur îlot. Ainsi, ces îlots sont des interfaces de résistance à la fois stables mais aussi dynamiques favorisant la dissémination des gènes de résistance. Une virulence accrue par la présence de ces îlots chez S. enterica n’a pas pu être confirmée ni dans le modèle d’infection expérimentale de C. elegans, ni dans une étude rétrospective chez l’homme (prévalence de 12%). En revanche, P. mirabilis avait tendance à être plus pathogène chez C. elegans lorsqu’il était porteur d’un îlot / Salmonella genomic island (SGI1) is an integrative mobilizable element initially described in an epidemic multidrug-resistant Salmonella Typhimurium DT104. Since this first report, many variants and related genomic islands (Proteus genomic island 1 (PGI1)) have been described among Salmonella enterica serovars and in Proteus mirabilis. These islands have a stable backbone and a highly variable multidrug-resistant (MDR) region. The objective of this work was to study SGI1 from clinical P. mirabilis isolates (University hospitals of Dijon and Lariboisière - Paris) and S. enterica (University hospital of Dijon) The prevalence of these islands ranged from 5% to 16% in P. mirabilis with at least one acquired resistance. The genotypic analysis revealed a wide diversity among isolates but also the presence of some clonal isolates harbouring SGI1 or PGI1. Genomic island sequencing revealed the great plasticity of MDR regions, primarily mediated by IS26. Thanks to IS26 movements, the MDR region gains resistance genes (such as blaCTX-M-15) present in structures initially detected in plasmids from widely distributed Enterobacteriaceae. Many species of Enterobacteriaceae that harbour IncA/C plasmids are able to acquire islands by conjugation. These islands are then incorporated into specific sites on the chromosome (trmE). They could also be completely excised from Enterobacteriaceae under antibiotic pressure in the presence of an IncA/C plasmid. Genomic islands should be regarded on the one hand as a steady interface of resistance and on the other hand as a dynamic interface conveying resistance genes. Finally, SGI1 of S. enterica was not found to increase virulence in a Caenorhabditis elegans model or in a retrospective clinical study (12% of prevalence). However, it seems that P. mirabilis becomes more virulent when it harbours SGI1 in Caenorhabditis elegans
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PERFIL DE RESISTÊNCIA DAS BACTÉRIAS GRAM-NEGATIVAS COMUMENTE ASSOCIADAS À INFECÇÕES DO TRATO URINÁ- RIO EM IDOSOS EM GOIÂNIA – GO, NO PERÍODO DE 2011- 2015Povoa, Christiano Patricio 08 September 2016 (has links)
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Previous issue date: 2016-09-08 / The urinary tract infections (UTI) are one of the most common types of infection,
both community as nosocomial, the ITU is caused by bacteria are more common
in men and in. The study was descriti-vo retrospective and prospective type, from
2011 to 2016 were analyzed from 3388 antibiograms of ITU of Community origin
in the elderly. The age of patients ranged from 60 to 100 years, with a mean age
of 73 years, and 77.28% occurred in women and 22.72% in men. The microranalyzed
organisms were Escherichia coli (75.65%) with 80.72% by Women's
res and 19.28% in men, followed by Klebsiella pneumoniae (16.59%) with
66.73% infection 33.27% in women and in men. Proteus spp. It was respon-sible
for 5.70% cases, with 70.47% occurred in women and 29.53% in ho-mens. Enterobacter
spp. It was the causative organism of UTI in 2.07%; 45.71% women and
54.29% in men. The highest prevalence of resistance to E. coli were to sulfonamide
(40.54%), Ciprofloxacin (35.04%), Nalidixic acid (34.92%), Cephalosporins
1st Generation (31,45%), Norfloxacin (24 , 50%), Penicillin (23.68%) and 3rd generation
cephalosporins (12.29%), an increase in the evolution of resistance to
cephalosporins 2nd generation (p = 0.0074). For K. pneumoniae, the major resistance
prevalence occurs to ram for Norfloxacin (16.73%), cephalosporins 3rd
Generation (20.46%), Aci-of Nalidixic (26.87%), Cephalosporins 1st Generation
(29 , 00%), Penicillin (33.99%), sulfonamide (35.05%), Nitrofurantoin (37.90%),
Gemifloxacin (46.09%) and ofloxacin (46.09%) with increased resistance evolution
Carbapenems for (p = 0.0271) and Cephalosporins 1st generation (p =
0.0496). Proteus spp., The major resistance prevalences were to Gati-floxacina
(12.95%), Norfloxacin (12.95%), penicillins (14.51%), cephalosporins on the 2nd
Generation (21.24%) , sulfonamide (36.27%), Cephalosporins 1st Ge-feed
(38.86%), Gemifloxacin (46.11%), ofloxacin (46.11%), nitrofurantoin (76.68%),
Nalidixic acid (81 , 87%) and levofloxacin (81.87%). For Enterobac-have spp.,
The major resistance prevalences were compared to Cefalospo-mandarins of 4th
Generation (15.71%), Gatifloxacin (21.43%), Norfloxacin (21.43%), Ciprofloxacin
(28.57 %), Moxifloxacin (28.57%), Nitrofurantoin (31.43%), 3rd generation cephalosporins
(32.86%), sulfonamide (38.57%), Gemifloxacin (42.86%), ofloxacin (42,
86%) 1st generation cephalosporins (44.29%), nalidixic acid (77.14%), Levofloxacin (77.14%) and Penicillins (97.14%) with au-ment in the evolution of resistance
to cephalosporins 2nd Generation (p = 0.0057). For empiric treatment of
complicated UTI due to the found resistance to the antimicrobials of choice, the
aminoglycosides, Carbapenems and monobactam can be used until they are
met, the causative agents of infection and susceptibility to tested Antimicro-bianos
and should be replaced by re-duced antimicrobial spectrum, but with high
power. / As infecções no trato urinário (ITU) correspondem a um dos tipos mais comuns
de infecção, tanto comunitária quanto nosocomial, sendo as ITU causadas por
bactérias são mais comuns, tanto em homens quanto em. O estudo foi descritivo
tipo retrospectivo e prospectivo, no período de 2011 a 2016. Foram analisados
3388 antibiogramas de ITU de origem comunitária em idosos. A faixa etária dos
pacientes variou de 60 até 100 anos, com média de idade de 73 anos, sendo
que 77,28% ocorreram em mulheres e 22,72% em homens. Os microrganismos
analisados foram Escherichia coli (75,65%), com 80,72% em mulheres e 19,28%
em homens, seguido por Klebsiella pneumoniae, (16,59%), com 66,73% infecções
em mulheres e 33,27% em homens. Proteus spp. foi responsável por 5,70%
casos, com 70,47% ocorreram em mulheres e 29,53% em homens. Enterobacter
spp. foi o organismo causador de ITU em 2,07%; 45,71% em mulheres e 54,29%
em homens. As maiores prevalências de resistência para E. coli foram para Sulfonamida
(40,54%), Ciprofloxacina (35,04%), Ácido Nalidíxico (34,92%), Cefalosporinas
de 1ª Geração (31,45%), Norfloxacina (24,50%), Penicilinas (23,68%)
e Cefalosporinas de 3ª Geração (12,29%), com aumento na evolução da resistência
para Cefalosporinas de 2ª Geração (p = 0,0074). Para K. pneumoniae, as
maiores prevalências de resistência ocorreram para Norfloxacina (16,73%), Cefalosporinas
de 3ª Geração (20,46%), Ácido Nalidíxico (26,87%), Cefalosporinas
de 1ª Geração (29,00%), Penicilinas (33,99%), Sulfonamida (35,05%), Nitrofurantoína
(37,90%), Gemifloxacina (46,09%) e Ofloxacina (46,09%) com aumento
na evolução da resistência para Carbapenêmicos (p = 0,0271) e Cefalosporinas
de 1ª Geração (p = 0,0496). Para Proteus spp., as maiores prevalências de resistência
foram para Gatifloxacina (12,95%), Norfloxacina (12,95%), Penicilinas
(14,51%), Cefalosporinas de 2ª Geração (21,24%), Sulfonamida (36,27%), Cefalosporinas
da 1ª Geração (38,86%), Gemifloxacina (46,11%), Ofloxacina
(46,11%), Nitrofurantoína (76,68%), Ácido Nalidíxico (81,87%) e Levofloxacina
(81,87%). Para Enterobacter spp., as maiores prevalências de resistência foram
em relação à Cefalosporinas de 4ª Geração (15,71%), Gatifloxacina (21,43%),
Norfloxacina (21,43%), Ciprofloxacina (28,57%), Moxifloxacina (28,57%), Nitrofurantoína
(31,43%), Cefalosporinas de 3ª Geração (32,86%), Sulfonamida
(38,57%), Gemifloxacina (42,86%), Ofloxacina (42,86%), Cefalosporinas de 1ª Geração (44,29%), Ácido Nalidíxico (77,14%), Levofloxacina (77,14%) e Penicilinas
(97,14%), com aumento na evolução da resistência para Cefalosporinas de
2ª Geração (p = 0,0057). Para o tratamento empírico das ITU complicadas, devido
à resistência encontrada para os antimicrobianos de primeira escolha, podem
ser usados os Aminoglicosídeos, Carbapenêmicos e Monobactama, até que
sejam conhecidos os agentes causadores das infecções e a susceptibilidade aos
antimicrobianos testados, devendo ser substituídos por antimicrobiano de espectro
reduzido, porém com potência elevada.
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Infecção urinária comunitária: aspectos epidemiológicos, clínicos e laboratoriais em crianças e adolescentes / Community-acquired urinary tract infection: epidemiological, clinical and laboratory aspects in children and adolescentsLo, Denise Swei 31 October 2017 (has links)
INTRODUÇÃO: Infecção do trato urinário (ITU) é doença cujos sinais e sintomas são frequentemente inespecíficos, especialmente em lactentes. Portanto, o conhecimento de seus aspectos epidemiológicos, clínicos e laboratoriais são relevantes para a adequada abordagem clínica. OBJETIVOS PRINCIPAIS: Descrever: a prevalência de ITU como motivo de atendimento em pronto-socorro geral de Pediatria; a variabilidade da frequência de ITU e dos agentes etiológicos em diversas faixas etárias e sexo; o perfil de sensibilidade antimicrobiana de Escherichia coli; o quadro clínico, laboratorial e evolutivo de lactentes jovens. OBJETIVOS SECUNDÁRIOS: Cálculo de sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo do corte de leucocitúria >= 10.000 leucócitos/mL para o diagnóstico de ITU em lactentes jovens. Comparar as diferenças de ITU por Escherichia coli e Staphylococcus saprophyticus em adolescentes do sexo feminino e discutir as melhores escolhas de terapia antimicrobiana empírica para uso na população estudada. MÉTODO: Estudo retrospectivo, descritivo, incluindo todos os casos de ITU (urocultura quantitativa com >= 50.000 UFC/mL por sondagem vesical ou >= 100.000 UFC/mL por jato médio) atendidos no Pronto-Socorro de Pediatria do Hospital Universitário da Universidade de São Paulo, de 01/01/2010 a 31/12/2012, idades entre zero a 15 anos incompletos. Resultados: Do total de 188.460 atendimentos realizados, 7994 colheram urocultura por suspeita de ITU; este diagnóstico foi confirmado em 1071 casos (prevalência: 0,57% do total de atendimentos e 13,4% das uroculturas incluídas). A proporção de casos entre sexo masculino e feminino foi: 1:0,3 em menores de três meses; 1:3,9 entre três meses a 12 anos e 1:12 entre 12 a 15 anos. Escherichia coli foi o principal agente responsável por 73,2% dos casos totais de ITU. Entretanto, outros agentes importantes foram Klebsiella pneumoniae (18,46%) e Enterococcus faecalis (7,7%) em lactentes jovens (menores de três meses de idade); Proteus mirabilis (30,8%) em meninos de três meses a 12 anos; Staphylococcus saprophyticus (25%) em adolescentes do sexo feminino entre 12 a 15 anos. A sensibilidade antimicrobiana de Escherichia coli foi observada acima de 80% para: amoxicilina/ácido clavulânico (87%), cefuroxima (98%), cefotaxima (98%), ceftriaxona (100%), cefepime (99%), amicacina (100%), gentamicina (97%), ciprofloxacina (98%), norfloxacina (94%), ácido nalidíxico (93%) e nitrofurantoína (97%). Em lactentes jovens, febre sem sinais localizatórios foi o sintoma mais frequente de ITU (77,8%). Exames subsidiários de hemograma e proteína C reativa foram de pouca utilidade clínica. O teste de nitrito positivo apresentou baixa sensibilidade: 30,8% (IC 95%: 19,9%-43,4%), porém elevada especificidade e valor preditivo positivo. Enquanto que o corte de leucocitúria > 10.000 leucócitos/mL para ITU revelou boa sensibilidade: 87,7% (IC 95%: 77,2%-94,5%), porém baixa especificidade e valor preditivo positivo. Nas adolescentes do sexo feminino entre 12 a 15 anos, houve menor positividade do teste do nitrito nas ITU por Staphylococcus saprophyticus do que nas ITU por Escherichia coli. Na população do presente estudo, a terapia empírica inicial recomendada seria: zero a três meses: tratamento parenteral com aminoglicosídeo ou cefalosporina de terceira geração; podendo associar ampicilina para cobertura de Enterococcus faecalis. Entre três meses a 15 anos: amoxicilina/ácido clavulânico ou cefuroxima ou ceftriaxona ou aminoglicosídeos. CONCLUSÕES: ITU é doença frequente em atendimentos de pronto-socorro. Os aspectos epidemiológicos, clínicos e laboratoriais são variáveis nas diversas faixas etárias e sexos; portanto, a abordagem deve ser individualizada em cada um destes segmentos / INTRODUCTION: Urinary tract infection (UTI) frequently presents with nonspecific signs and symptoms, particularly in infants. Therefore, the understanding of its epidemiological, clinical and laboratory aspects are relevant to its appropriate clinical approach. MAIN OBJECTIVES: To describe: the prevalence of UTI as a cause for attending the pediatric emergency department; the variability of the frequency of UTI and etiological agents in different age groups and sexes; the antimicrobial sensitivity profile of Escherichia coli; the clinical features, laboratory findings and treatment outcomes in young infants. SECONDARY OBJECTIVES: To evaluate sensitivity, specificity, positive predictive value and negative predictive value of pyuria >= 10,000 leukocytes/mL for screening UTI in young infants. To compare UTI due to Escherichia coli with UTI due to Staphylococcus saprophyticus in female adolescents and to discuss the best empirical antimicrobial treatment in the population studied. METHODS: Retrospective, descriptive study, including all cases of UTI (urine culture of >= 50,000 CFU/mL obtained by bladder catheterization or >= 100,000 CFU/mL obtained by midstream-voided method) attended at the pediatric emergency department of University Hospital of the University of São Paulo, from 01/01/2010 to 12/31/2012, ages from zero to 15 years old. Results: Of 188,460 visits in this period, 7994 collected urine culture on suspicion of UTI. This diagnosis was confirmed in 1071 cases (prevalence: 0.57% of total visits and 13.4% of urine cultures included). The proportion of cases between male and female was: 1: 0.3 in children younger than three months old; 1: 3.9 from three months to 12 years old and 1:12 from 12 to 15 years old. Escherichia coli was the main etiology responsible for 73.2% of total cases of UTI. However, other important agents were Klebsiella pneumoniae (18.46%) and Enterococcus faecalis (7.7%) in young infants (under three months of age); Proteus mirabilis (30.8%) in boys from three months to 12 years old; Staphylococcus saprophyticus (25%) in female adolescents aged 12-15 years. The antimicrobial sensitivity of Escherichia coli was still above 80% for amoxicillin / clavulanic acid (87%), cefuroxime (98%), cefotaxime (98%), ceftriaxone (100%), cefepime (99%), amikacin (100%), gentamicin (97%), ciprofloxacin (98%), norfloxacin (94%), nalidixic acid (93%) and nitrofurantoin (97%). In young infants, the absence of another source of fever was the most frequent UTI symptom (77.8%). Laboratory parameters including peripheral white blood cell count and C-reactive protein concentration were of limited clinical usefulness. The sensitivity of nitrite testing for bacteriuria was low: 30.8% (95% CI: 19.9%-43.4%), but had high specificity and positive predictive value. Pyuria> 10,000 leukocytes / mL for identifying UTI had high sensitivity: 87.7% (95% CI: 77.2%-94.5%), but low specificity and positive predictive value. In female adolescents aged 12 to 15 years old, there were few positive nitrite tests in UTI due to Staphylococcus saprophyticus compared with UTI due to Escherichia coli. In the population studied, the initial empirical therapy recommended would be: from zero to three months old: parenteral treatment with aminoglycoside or third generation cephalosporin; it could be associated with ampicillin to treat Enterococcus faecalis. Between three months to 15 years old: amoxicillin / clavulanic acid or cefuroxime or ceftriaxone or aminoglycosides. In cystitis: in addition to amoxicillin / clavulanic acid or cefuroxime; nitrofurantoin is also a good option for Staphylococcus saprophyticus UTI whereas nalidixic acid is also a nice choice for Proteus mirabilis UTI. CONCLUSIONS: UTI is a common disease in emergency department visits. The epidemiological, clinical and laboratory aspects are variable in the different age and sex groups; therefore, the approach must be individualized in each of these groups
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Enterobactérias e fatores de virulência em cepas de Escherichia coli isoladas de psitacídeos / Enterobacteriaceae and virulence factors in strains of Escherichia coli isolated from psittacines birdsCorrêa, Isadora Mainieri de Oliveira 17 February 2012 (has links)
Programa de Apoio aos Planos de Reestruturação e Expansão das Universidades Federais / The microbiota intestinal of Psittaciformes is mainly composed of Gram positive bacteria, is considered a sign of illness the presence of Gram negative bacteria. Wild birds are important to public health by harboring pathogens able of zoonotic transmission. The displacement of these birds, such as occurs in the trafficking of wild animals, is a propagation mechanism of new endemic foci of infections agents to long distances from where they were acquired. In this study we examined the presence of enterobacteria in psittacines using samples of organs of birds received for necropsy at the Laboratório Central de Diagnóstico de Patologias Aviárias (LCDPA) situate in the Departamento de Medicina Veterinária Preventiva (DMVP) at Centro de Ciências Rurais (CCR) of the Universidade Federal de Santa Maria (UFSM). We also collected samples using swabs of cloaca and crop, in live birds, kept in captivity in order to monitor the possible presence of pathogenic bacteria. Escherichia coli was considered the predominant bacteria in most samples, then after microbiological analysis and confirmation of E. coli isolates, we selected 28 colonies, which were tested for virulence factors iss, this gen is associated with the strain s ability to resist the lytic effects of serum, and iutA an outer membrane receptor of involved in the high affinity binding of iron-aerobactin. It is hoped that the data obtained in this research will help in establishing the health status of psittacines helping maintain the species and preventing risks to public health. / A microbiota intestinal de Psitaciformes é composta principalmente por bactérias Gram positivas, não se considerando saudável a presença de bactérias Gram negativas. As aves silvestres possuem importância para a saúde pública por albergarem patógenos passíveis de transmissão zoonótica. O deslocamento territorial dessas aves, como o que ocorre no tráfico de animais selvagens, constitui um mecanismo de propagação de novos focos endêmicos de agentes infecciosos a grandes distâncias dos locais onde foram adquiridos. Neste trabalho analisamos a presença de enterobactérias em psitacídeos utilizando amostras de órgãos de aves recebidas para necropsia na rotina do Laboratório Central de Diagnóstico de Patologias Aviárias (LCDPA) situado no Departamento de Medicina Veterinária Preventiva (DMVP) do Centro de Ciências Rurais (CCR) da Universidade Federal de Santa Maria (UFSM). Também foi realizada coleta de suabes cloacais e de inglúvio em aves vivas mantidas em cativeiro visando monitorar a presença de possíveis bactérias patogênicas. Escherichia coli foi considerada a bactéria predominante na maioria das amostras, então após análise microbiológica e confirmação dos isolados de E. coli, selecionamos 28 colônias, as quais foram testadas para os fatores de virulência iss, relacionado com a capacidade da cepa em resistir aos efeitos líticos do soro, e iutA, sendo este gene um receptor de membrana externa dos compostos sideróforos da aerobactina (genes iuc) que é um sistema de captação de ferro pelo qual E. coli expressa afinidade. Espera-se que os dados obtidos nessa pesquisa contribuam no estabelecimento do estado sanitário de psitaciformes auxiliando na manutenção da espécie e prevenindo riscos à saúde pública.
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Aesthetic Details and Player Behavior : a study on how the colors of checkers in backgammon affect players’ choices of actionBergqvist, Andreas January 2013 (has links)
Based upon earlier studies in the fields of psychology and game design by Frank and Gilovich (1988) and Yee (2007), this paper examines the influence of color on players of backgammon. The paper examines the probability of a player hitting an opponent’s piece when possible in backgammon depending on the color of the checkers. The data sample was compared using a t-test but showed no significant correlation. Based upon the results it was concluded that the Proteus Effect is not as effectively achieved through units in board games compared to avatars in virtual worlds.
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The Role of Avatar Creation and Embodied Presence in Virtual Reality Job InterviewsMenon, Akash January 2021 (has links)
In this work, a prototype of a job interview training application in virtual reality is evaluated. This paper explores the factors affecting the usability and embodiment of an avatar and how they related to job interviews in a virtual reality setting. A between-group study was conducted (n=15) to measure the effect on the embodiment of an avatar that creating and customizing an avatar had compared to picking from pre-defined ones. Participants had to undergo a job interview in virtual reality with their avatars. A mixed-method approach was followed with data collection using both post-experiment questionnaires and recorded semi-structured interviews. No significant results could be established between the avatar selection process and the embodiment towards the avatar. The thematic analysis of the interview data and the quantitative data analysis resulted in design guidelines for future job interview training applications. Critical aspects of the design guidelines outline the need to promote and enable users to use hand gestures, allow basic customization of their avatars, and put special attention to the design and behavioral fidelity of the interviewer. / I det här arbetet, utvärderas en prototyp av en träningsapplikation för jobbintervjuer. Det här arbetet utforskar faktorer som påverkar användbarheten och förkroppsligandet av en avatar och hur dessa faktorer relaterar till jobbintervjuer i virtuell verklighet. En studie utfördes med två olika grupper (n=15) för att mäta effekten av förkroppsligande av avatarer som processen av att skapa och anpassa en avatar hade jämfört med att enbart välja bland förvalda avatarer. Deltagarna fick delta i jobbintervju i virtuell verklighet med sina avatarer. En blandad metod användes med datainsamling genom både formulär och inspelade intevjuer. Inga statistisk signifikanta resultat kunde erhållas mellan urvalsprocessen av avataren och förkroppsligande av avataren. Den tematiska analysen av intervjudatan resulterade i designriktlinjer som utlyser behovet av att möjliggöra användare att fritt använda händerna, göra enkla modifikationer av sina avatarer och lägga extra mycket fokus på designen av intervjuaren.
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Lipopolysaccharide (LPS) core biosynthesis in "Proteus mirabilis" / Estudio de la biosíntesis del núcleo de lipopolisacarido (LPS) en "Proteus mirabilis"Aquilini, Eleonora 11 January 2013 (has links)
Urinary tract infection (UTIs) is an extremely common disease. Proteus mirabilis is a common cause of UTI in individuals with functional or structural abnormalities or with long-term catheterization, it forms bladder and kidney stones as a consequence of urease-mediated urea hydrolysis. Known virulence factors, besides urease, are flagella, fimbriae, outer membrane proteins, hemolysins, amino acid deaminase, protease, capsule and lipopolysaccharide (LPS).
Study of LPS core is particularly relevant for several reasons: it is a conserved region, although it is increasingly clear that there is some variability at the genus or groups of similar genera, its chemical structure modulates the endotoxic activity of lipid A, alteration of the LPS core, which generates less virulent bacteria, encourages the search of substances that interfere with the biosynthesis of this region, and conserved regions of the core LPS could be useful as antigens in preventing diseases caused by pathogens that contain these conserved regions.
The specific aims of this project have been to identify and functionally characterize genes involved in core LPS biosynthesis in P. mirabilis, to elucidate the mechanism of incorporation of galactosamine (GalN) to the core LPS, to identify genes coding for phosphoethanolamine (PEtN) modifications, and to characterize and to study the biological effects of the gene encoding the PEtN transferase involved in the modification of the second heptose residue (L,D-HepII).
We found that P. mirabilis has most of the genes for the biosynthesis of LPS core grouped in the waa cluster in the chromosome. Despite this, additional genes required for core LPS biosynthesis are found outside the waa cluster. The pentasaccharide of the inner core, shared by all Enterobacteriaceae, is biosynthesized in P. mirabilis, by the sequential activity of a bifunctional transferase (WaaA) and three heptosyltransferases (WaaC, WaaF, and WaaQ). These enzymes are transcribed from genes located inside the waa cluster, and are conserved in P. mirabilis strains analyzed; for more, they show a high identity and similarity level to homologues proteins of Escherichia coli, Klebsiella penumoniae and Serratia marcescens. The waaL gene, coding for the O-antigen polymerase ligase, is found adjacent to the classic waa cluster. Downstream this gene, four genes encoding enzymes belonging to the 4 (walM, walN, and WalR), and 9 (walO) glycosyltransferase family were found. Even if members of these families were related to LPS core biosynthesis in several Gram-negative bacteria, in P. mirabilis they do not appear to be involved in the biosynthesis of the reported core LPS structures. The presence of the disaccharide hexosamine (HexN)-1,4-galacturonic acid (GalA) is a feature of P. mirabilis LPS outer core. Depending on the nature of the HexN outer core residue, two different homologues for N-acetyl-hexosamine transferases are present in the waa cluster: wabH or wabP. Altought the incorporation of glucosamine into LPS core requires an acetylglucosaminyltransferase (WabH) and a deacetilase (WabN), the incorporation of GalN requires three enzymes: an acetylgalactosaminyltransferase (WabP), a deacetilase (WabN) and an epimerase (gne). An amplification test with specific primers for this two different homologues can be used to predict the HexN nature in P. mirabilis LPS cores. The strain-specific genes wamB and wamC code for a galactosyltransferase and a heptosyltransferase respectively in strain R110 of P. mirabilis. The enzyme encoded by gene wamD is a N-acetylglucosaminyltransferase, and it is found in strain 51/57 of P. mirabilis. WamA, coded by wamA gene in the waa cluster of strains R110, 50/57, TG83 and HI4320, is a heptosyltransferase responsible for the incorporation of a quarter residue of heptose (Hep), in DD configuration, to the GalA II of the outer core. In P. mirabilis strain 51/57, a gene coding a protein of the Mig-14 family was identified inside the waa cluster, this localization appears to be an exception in the Enterobacteriaceae family. Inspection of the whole genome of P. mirabilis HI4320 did not allow the identification of a mig-14 similar gene. There are three putative PEtN transferases in the genome of P. mirabilis: PMI3040, PMI3576, and PMI3104. The gene identified as eptC (PMI3104) transfers the moiety of PEtN to the O-6 position of L,D-Hep II (HepII6PEtN). The absence of the positive charge due to PEtN residue doesn't affect the bacterial growth kinetics in lab conditions in rich or defined media, but causes a moderate destabilization of the outer-membrane. Despite the lack of the PEtN residue on the Hep II in P. mirabilis LPS core, has no statistically effects during urinary tract infection assays in mouse model, the absence of this modification causes an increase sensitivity to complement in non-immune human sera. / P. mirabilis no es una causa frecuente de infecciones urinarias en el huésped normal, más bien infecta el tracto urinario con alteraciones funcionales o anatómicas, o instrumentación crónica como el cateterismo. P. mirabilis está a menudo asociado con cálculos urinarios e incrustaciones de los catéteres y es, particularmente importante, en pacientes con cateterización prolongada. Las infecciones del tracto urinario asociadas a cateterización son mundialmente reconocidas como la causa más común de infección asociada a tratamientos en ambiente hospitalario. El LPS es un factor de virulencia importante en bacterias Gram negativas patógenas. También conocido como endotoxina, es una molécula glicolipídica que constituye la estructura mayoritaria de la cara externa de la membrana externa (OM).
En Proteus mirabilis la mayoría de los genes responsables de la biosíntesis de núcleo de LPS están localizados en el cromosoma, en el agrupamiento génico waa. A pesar de esto, algunos genes adicionales, necesarios para la biosíntesis del núcleo de LPS, se encuentran ubicados fuera del agrupamiento génico waa. El pentasacárido del núcleo interno, común a todas las Enterobacteriáceae, se biosintetiza en P. mirabilis, por la actividad secuencial de una transferasa bifunciona (WaaA) y tres heptosiltransferasas (WaaC, WaaF, y WaaQ).
La presencia del disacárido HexN‐1,4‐GalA es característica del núcleo externo de LPS en P. mirabilis. Dependiendo de la naturaleza del residuo de HexN, se encuentran, en el agrupamiento génico waa, dos HexNAc transferasas diferentes: wabH o wabP. El gen eptC (PMI3104) codifica para la enzima que transfiere el residuo de fosfoetanolamina a la posición O-6 de la L,D-Hep II (HepII6PEtN), en el núcleo de LPS de P. mirabilis. La ausencia de la carga positiva del residuo de fosfoetanolamina no afecta a la cinética de crecimiento de las bacterias en condiciones standard de laboratorio sea en medios ricos o definidos. La ausencia del residuo fosfoetanolamina provoca una desestabilización moderada de la membrana externa que se traduce en una disminución de la MIC para SDS.
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Proteus : A new predictor for protean segmentsSöderquist, Fredrik January 2015 (has links)
The discovery of intrinsically disordered proteins has led to a paradigm shift in protein science. Many disordered proteins have regions that can transform from a disordered state to an ordered. Those regions are called protean segments. Many intrinsically disordered proteins are involved in diseases, including Alzheimer's disease, Parkinson's disease and Down's syndrome, which makes them prime targets for medical research. As protean segments often are the functional part of the proteins, it is of great importance to identify those regions. This report presents Proteus, a new predictor for protean segments. The predictor uses Random Forest (a decision tree ensemble classifier) and is trained on features derived from amino acid sequence and conservation data. Proteus compares favourably to state of the art predictors and performs better than the competition on all four metrics: precision, recall, F1 and MCC. The report also looks at the differences between protean and non-protean regions and how they differ between the two datasets that were used to train the predictor.
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Does immersion affect cognitive transfer in FPS games? : A study of cognitive abilities transfer of engaging in first-person shooter games through immersion experiencesChainilwan, Jakkapan January 2023 (has links)
First-person shooter (FPS) games are frequently associated with immersion due to their use of a first-person perspective camera, which gives players the impression that they are a part of the game world. When combined with the proteus effect and identification, players can achieve a complete sense of immersion in the character they are portraying. The objective of this study is to delve into the cognitive benefits of engaging in FPS games and to establish a correlation between the level of immersion and cognitive transfer. The data collected from participants who completed reaction tasks were analyzed in conjunction with the IEQ (Immersive experience questionnaire) scores. The IEQ provided quantitative data on immersion. By assessing the participants' cognitive abilities based on their reaction task performance, the study found that playing FPS games can improve accuracy but not affect reaction time. Furthermore, the study found no correlation between immersion and cognitive transfer.
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