Previous studies of the relationship between egg size and the embryonic development time showed a positive correlation between the two variables at interspecies level, thus offering the idea that the evolution of the latter could be a limiting factor for enlarging the size of eggs during evolution. Some research into interspecies and intraspecific level of reptiles doesn't confirm this correlation. At the same time, the relationship between the development time and egg size is influenced by many factors, such as shifts in ontogenetic stages of the embryo at the time of ablation of eggs, due to temperature and humidity, the presence of embryonic diapause during embryogenesis or synchronization of hatching time, of which the authors of previous studies took no account or filtered out inaccurately. I think that most of these factors can be well controlled in intraspecific studies, but, variation in egg size within species also tends to be small, which prevents a reliable test for correlation. The solution can be to compare closely related species with high variability in the size of the eggs, in our case the geckos of the genus Paroedura and family Eublepharidae. I eliminated temperature effects by comparing the time of incubation in two equal constant temperatures. The results show that, in this...

Made available in DSpace on 2016-08-17T18:39:47Z (GMT). No. of bitstreams: 1 5403.pdf: 1214659 bytes, checksum: ec578be4027b3263202dca89b2b6f55a (MD5) Previous issue date: 2013-04-02 / Financiadora de Estudos e Projetos / Photodynamic Therapy (PDT) has been helping medicine in treatment infectious diseases and tumors. PDT's principle is based on a photosensitizer (PS) that is photoactivated by light at specific wavelength which generates reactive oxygen species that induces cell death and/or microorganism inactivation (PDI - photodynamic inactivation). The optimum incubation time of the photosensitizer, whereas the structural and metabolic differences of each microorganism, is important for the more efficient effect of PDI. Curcumin, being a natural PS, has been gaining ground in scientific research and has shown satisfactory results in microbiological control when associated with PDI, but there are no studies on the influence of incubation time of the PS with the bacterial cell. The present study aimed to evaluate the incubation time of curcumin on PS PDI and can therefore assist in determining future research the perfect time to contact the PS in bacteria of different wall compositions: Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa). Samples of microorganisms were cultured in TSB broth (Triptic Soy Broth) and incubated at 37 °C for 24 hours. The PS was solubilized in dimethylsulfoxide (DMSO) to achieve concentrations of 20 mM stock, subsequently diluted to obtain the final concentrations. Light source was used at a wavelength of 460nm, and final dose of 30 J/cm2. After the incubations with the FS and irradiation decimal dilutions of the samples were plated on TSA medium (Triptic Soy Agar) and incubated at 37 °C for 48 hours, and the counts performed. The PDI decreased approximately 7 logs S. aureus at a concentration of 1μM with incubation time of 30 minutes, while for P. aeruginosa was reduced by 2 logs with a maximum concentration of 50 μM with the same incubation time. Tests were conducted where PS withdrawing means before illumination, but the process was not found reductions as those obtained without the procedure. In general, the best incubation time was 30 minutes in all concentrations and for both microorganisms. / A Terapia Fotodinâmica (TFD) vem auxiliar a medicina no tratamento de doenças, tanto de etiologia microbiana quanto tumoral. O princípio da TFD baseia-se em um fotossensibilizador (FS) que se fotoativado por luz em comprimento de onda específico, gera espécies reativas de oxigênio que induz a morte celular e/ou inativação de microrganismos (IFD inativação fotodinâmica). O tempo de incubação ideal do fotossensibilizador, considerando as diferenças estruturais e metabólicas de cada microrganismo, é importante para eficácia da IFD. A curcumina, por ser um FS natural, vem ganhando espaço nas pesquisas científicas, tendo mostrado resultados satisfatórios no controle microbiológico quando associada com a IFD, porém ainda não existem estudos sobre a influência do tempo de incubação do FS com a célula bacteriana. O presente estudo teve como objetivo avaliar o tempo de incubação do FS curcumina na IFD, podendo assim auxiliar em futuras pesquisas determinando o tempo ideal para o contato do FS em bactérias de diferentes composições de parede: Gram-positivas (Staphyloccocus aureus) e Gram-negativas (Pseudomonas aeruginosa). As amostras dos microrganismos foram cultivadas em caldo TSB (Triptic Soy Broth) e incubadas a 37 °C por 24 horas. O FS foi solubilizado em dimetilsulfóxido (DMSO) para atingir a concentração estoque de 20 mM, posteriormente diluído para obter as concentrações finais. Foi utilizada fonte de luz no comprimento de onda 460 nm, e dose final de 30 J/cm2. Após as incubações com o FS e a irradiação, diluições decimais das amostras foram plaqueadas em meio TSA (Triptic Soy Agar) e incubadas a 37 °C por 48 horas; e realizada as contagens. A IFD reduziu aproximadamente 7 logs de S. aureus na concentração de 1 μM com tempo de incubação de 30 minutos, enquanto para P. aeruginosa houve redução de no máximo 2 logs com concentração de 50 μM com o mesmo tempo de incubação. Foram realizados testes onde se retirava o FS do meio antes da iluminação, porém com o processo não foi encontrado reduções como as obtidas sem o procedimento. Em geral, o melhor tempo de incubação foi o de 30 minutos em todas as concentrações de FS e em ambos os microrganismos.

The degree work is concentrated on the problems of the epidemic as to acute viral gastro-enteritides of nosocomial nature occurring in the Mental Home Bohnice in the years 2003 {--} 2009. I chose for my work the methodology of quantitative research in the form of an epidemiological descriptive study with the technique ``data collection and analysis{\crq}q. The infectious diarrhoeal affections are very current all the time and great importance in developing and even in advanced countries of the world. About 5 {--} 10 million people are dying of diarrhoea often connected with undernourishment in developing countries of Asia, Africa and Latin America per year, whereof 4,6 millions are children aged up to 5 years. The infection diarrhoeal affections in advanced countries of the world are important mainly as to their high frequency because they represent the second most frequent infection just behind the infection of air passages. The theoretical part of the work is concentrated on general characterization of the acute viral gastro-enteritis, on the process of spreading, on the most frequent aetiologic agents and on the new possibilities of diagnosis and therapy. The attention is also paid to the observance of antiepidemical measures and rules fixed in the hygienic and antiinfectious regimen, that prevent further spreading of the diseases in the case that an epidemic has broken out. In this connection, the basic profile and structure of the Mental Home Bohnice is also presented inclusive of important facts concerning the hospitalized patients. These patients form a very specific group of persons in respect to the occurrence of epidemics caused by viral diarrhoeal diseases as they are hospitalized in an isolated environment often for long term and their heath condition depends on psychiatric diagnosis. The performed investigation resumes the general judgement on the problems of epidemics caused by the acute viral gastro-enteritides in the Mental Home. It determines the most frequent aetiologic agents giving rise to this disease and analyzes these epidemics in relation to the age and sex of the patients. Another aim of the work was to explain the seasonal nature of the epidemics and to evaluate the efficiency of antiepidemical measures taken in this establishment. It is necessary to conclusion that the epidemical occurrence of viral gastro-enteritides was registered in Mental Home Bohnice even before the year 2003, but the aetiologic agents could not be specified in greater detail owing to the possibilities of virologic diagnostics being at disposal at that time.

Les mycotoxines sont des molécules toxiques produites par de nombreuses espèces fongiques. Les seules mycotoxines avérées aujourd’hui cancérigènes pour l’homme sont les aflatoxines. Elles sont produites par le genre Aspergillus principalement et sont retrouvées tout au long de la chaine alimentaire (champs, stockage, transformation, etc.). A cause du réchauffement climatique, la France devient de plus en plus exposée à la présence de ces mycotoxines. Afin de limiter l’exposition des consommateurs, de nombreuses stratégies de prévention ou de décontamination sont développées. Dans ce contexte, nous avons recherché à mettre au point un système de lutte biologique permettant de prévenir la production d’aflatoxines sur le maïs au champ. Pour cela, nous avons choisi des bactéries issues du sol et déjà connues pour être commercialisées pour la lutte biologique, les actinomycètes. Nous avons étudié l’interaction in vitro sur boites de Pétri entre Aspergillus flavus, principal producteur d’aflatoxines, et certains actinomycètes. Nous avons démontré que l’interaction peut réduire la concentration en aflatoxines mesurée par HPLC. De plus, certains isolats bactériens sont aussi capables de réduire, en culture pure, la concentration d’aflatoxine B1 dans le milieu. Des premiers tests d’adsorption ont été réalisés pour comprendre la nature de ce mécanisme. Par ailleurs, une étude approfondie via RT-qPCR sur 6 souches bactériennes du genre Streptomyces sp. A montré que celles-ci étaient capables d’impacter l’expression de différents gènes impliqués dans la voie de biosynthèse chez A. flavus et A. parasiticus. Enfin, nous avons complété les données déjà existantes sur l’impact de facteurs environnementaux (température, disponibilité en eau et du temps d’incubation) sur la production d’aflatoxines. / Mycotoxins are toxic contaminants of foodstuffs produced by a wide range of fungal species. Aflatoxins are the only mycotoxins carcinogenic for humans. They are mainly produced by the Aspergillus genus and can be found at each step of the agrofood chain (e.g. field, storage, process). Due to climate changes, France is starting to be exposed to aflatoxins. In order to limit the consumer exposure, many prevention or decontamination techniques have been developed. To this aim, we started the development of a biocontrol against aflatoxins accumulation for maize field application. Actinomycetes, are soil-borne bacteria that has already been commercialized as biocontrol. In Petri dishes, we studied the in vitro interaction between some actinomycetes and Aspergillus flavus, the main aflatoxins producer. We revealed that the interaction reduced the aflatoxins content (monitored by HPLC). Moreover, some bacterial isolates were able to reduce pure-aflatoxin B1 added in the medium. To understand this mechanism, adsorption tests has been conducted. Otherwise, RT-qPCR methodology was used to study the impact of Streptomyces-Aspergillus sp. on aflatoxin gene expression. Finally, the current knowledge of the impact of environmental factors (temperature, water activity and incubation time) on aflatoxins production was supplemented.