The procedure of Takimoto, Denault, and Hotta was followed in order to prepare 4-amino-3-hydrazino-5-methyl-s-triazole hydrochloride (II) and its precursor, triamino-guanidine hydrochloride (I).

Master of Science / Department of Grain Science and Industry / Bhadriraju Subramanyam / The insecticides, β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin, are approved in the United States for treating empty bin surfaces. Chlorpyrifos-methyl plus deltamethrin and spinosad insecticides are approved for direct treatment of wheat. The efficacy of commercial formulations of β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin at labeled rates was evaluated against adults of 16 field strains of the red flour beetle, Tribolium castaneum (Herbst); seven strains of sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grain borer, Rhyzopertha dominica (F.). Concrete arenas in plastic Petri dishes (9 cm diameter) were used to simulate the concrete floor of empty bins. The time for ~100% knockdown and mortality of adults of laboratory strains of the three species was first established by exposing them to insecticide-treated concrete surfaces for 1 to 24 h. Adults of field strains of each species were exposed to specific established insecticide-time combinations. Mortality of all species was lower than knockdown, suggesting recovery after seven days when placed on food. Chlorpyrifos-methyl plus deltamethrin did not control all R. dominica and most O. ]surinamensis field strains. β-cyfluthrin was extremely effective against R. dominica but ineffective against T. castaneum and O. surinamensis field strains, even at four times the high labeled rate. Field strains of R. dominica were highly susceptible to spinosad and chlorpyrifos-methyl plus deltamethrin at labeled rates on hard red winter wheat. Strains of T. castaneum and O. surinamensis were susceptible only to the latter insecticide. Dose-response tests with spinosad on the two least susceptible field strains of each species showed the lethal dose for 99% mortality (LD[subscript]99) for T. castaneum and R. dominica field strains were similar to that of the corresponding laboratory strains. Corresponding values for the two O. surinamensis field strains were significantly greater (~6 times) than the laboratory strain. The effective dose for progeny reduction (ED[subscript]99) of only one R. dominica field strain was significantly greater (~2 times) than that of the laboratory strain. The baseline susceptibility data of field strains of three insect species to spinosad will be useful for monitoring resistance development once this product is commercially released as a grain protectant.

Doctor of Philosophy / Department of Entomology / Thomas W. Phillips / Robert "Jeff" J. Whitworth / Dry-cured ham is protected from infestations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) with the fumigant methyl bromide. Developing feasible alternatives to methyl bromide is necessary due to the phase out of methyl bromide. The effectiveness of food-safe compounds for preventing infestations of T. putrescentiae on dry-cured hams was evaluated by dipping ham pieces in solutions of various food additives. Propylene glycol (1, 2-propanediol), lard, ethoxyquin and butylated hydroxytoluene prevented or significantly reduced mite population growth. A combination of carrageenan + propylene glycol alginate + 40% propylene glycol was effective in reducing mite numbers on treated whole-aged hams compared with untreated hams. Dose/response tests with twelve registered residual insecticides were conducted to assess contact toxicity to T. putrescentiae. Three of these insecticides were evaluated for persistence over a 2-month period on different surfaces. Commercial formulations of deltamethrin plus chlorpyrifos-methyl, chlorfenapyr, and malathion showed promising results for contact toxicity against T. putriscentiae. Chlorfenapyr applied to metal, concrete, and wood resulted in 100% mortality of treated ham mites for up to 8 weeks. The effect of high and low temperatures on mortality of T. putrescentiae was studied in the laboratory. Groups of 10 eggs and groups of a mixture of 40 adults and nymphs were separately exposed to several high and low temperatures, ranging from +35 to 45°C and from −20 to +5°C, for several time periods. Eggs were found to be more tolerant to both high and low temperatures compared with adults and nymphs. Results showed that high temperatures from 40-45°C killed all T. putrescentiae eggs, adults, and nymphs within 4-1 d, while −10°C or lower killed all the same stages in less than 1 d. Combinations of the fumigant sulfuryl fluoride (SF) applied under high temperatures ranging from 25-40ºC, were studied to determine the highest temperature, shortest exposure time, and the lowest value of a concentration-by-time product (CTP) of SF against T. putrescentiae. Results showed that complete control of all life stages of T. putrescentiae was achieved at 40ºC with SF. More than one day of exposure was required to kill adults and nymphs and eggs at 40ºC at a CTP close to the EPA labeled rate of 1500 gh.m⁻³. Results indicated that adults and nymphs were more susceptible to SF compared to eggs. This study focused on investigating different control methods for T. putrescentiae in dry-cured ham facilities and most of examined techniques are preventive, although some of them can be applied as remedial methods after mite infestations are noticed.

Developing microbial systems capable of converting low cost lipids into value added products depends on the ability to acquire substrates from the growth media. Saccharomyces cerevisiae can acquire free fatty acids from the growth media and a portion of these lipids can be converted into new lipid products. However, they cannot acquire complex lipids from the growth media unless a nonspecific lipase is included. To circumvent lipase addition, we are genetically engineering S. cerevisiae to secrete a lipase into the growth media. We selected the LIP2 gene from Yarrowia lipolytica, which encodes a nonspecific lipase. Several modifications were made to the LIP2 gene to improve processing. Results identified strains secreting the most lipase. From these results, high producing strains were inserted into an oil inducible vector. Halo assays confirmed lipase secretion, while measuring the fatty acid composition confirmed triacylglycerol breakdown, and yeast uptake of the free fatty acids released.

<p>QCR 20161026</p>

O Brasil destaca-se como um dos maiores produtores mundiais de mamão, fruto apreciado em todo o mundo pelo sabor e polpa delicada. Os compostos voláteis contribuem para a formação do aroma do fruto, o que faz deles essenciais para o desenvolvimento de características sensoriais que definem sua apreciação pelos consumidores. Os principais compostos de aroma do mamão incluem, principalmente, terpenos, ésteres, aldeídos, álcoois, ácidos orgânicos e cetonas, com destaque para o monoterpeno linalool que é o composto mais abundante na cultivar \'Golden\'. Embora a biossíntese de compostos voláteis seja particularmente afetada pelos tratamentos para consevação pós-colheita, estes são essenciais para a comercialização do mamão, em vista de sua alta perecibilidade. O uso de baixas temperaturas tem sido um dos métodos mais empregados para extensão de vida pós-colheita do mamão. Precedentes da literatura indicam que o tratamento pós-colheita com metil jasmonato (MJ) é capaz de reduzir possíveis efeitos prejudiciais decorrentes do armazenamento a baixa temperatura. Além disso, a aplicação do metil jasmonato em frutos é capaz de estimular a atividade de enzimas das vias de produção de compostos voláteis. Desta forma, o presente trabalho tem por objetivo avaliar os efeitos da aplicação pós-colheita do MJ em mamão (Carica papaya L. cv \'Golden\'), focando os efeitos sobre as vias de biossíntese de componentes voláteis do aroma, em frutos amadurecidos a temperatura de 22ºC, assim como em outros armazenados a 10ºC seguido de transferência a 22ºC para o pleno amadurecimento. Além dos perfis de compostos voláteis, também foram avaliados os perfis de respiração, produção de etileno, cor da casca, quantificação de MJ e expressão gênica de linalool sintase (LIS). Dada a importância do linalool para o aroma característico do mamão, as variações na transcrição de um gene da linalool sintase foram avaliadas buscando correlacioná-las aos efeitos dos tratamentos na produção dos compostos voláteis. O tratamento com MJ influenciou a produção de compostos voláteis, particularmente de linalool e hexanal nos grupos mantidos a 10ºC. Os frutos tratados com o hormônio apresentaram maior abundância do composto quando comparados ao grupo controle. Embora o protocolo de tratamento empregado não tenha conseguido recuperar os altos níveis encontrados nos frutos armazenados a 22ºC, não se exclui a possibilidade de que outros desenhos experimentais possam responder de maneira ainda mais satisfatória a este mesmo tratamento / Brazil stands out as one of the world\'s largest producers of papaya, fruit appreciated worldwide for it taste and delicate pulp. The volatile compounds contribute to the formation of the flavor of the fruit, making them essential for the development of sensory characteristics that define their appreciation by consumers. The main papaya flavor compounds include mainly terpenes, esters, aldehydes, alcohols, organic acids and ketones, especially the monoterpene linalool which is the most abundant compound in the cultivar \'Golden\'. Although the biosynthesis of volatile compounds is particularly affected by postharvest treatments for conservation, those are essential for the marketing of papaya, in view of their high perishability. The use of low temperatures has been one of the most used methods for extension of papaya postharvest life. Previous literature indicate that postharvest treatment with methyl jasmonate (MJ) is capable of reducing possible adverse effects arising from storage at low temperature. Furthermore, the application of methyl jasmonate in fruits is able to stimulate the activity of the enzymes of volatiles production pathways. Thus, this study aims to evaluate the effects of postharvest application of MJ in papaya (Carica papaya L. cv \'Golden\'), focusing on the effects in the biosynthetic pathways of volatile aroma compounds in fruit ripened to temperature of 22ºC, as well as other stored at 10ºC followed by transfer to 22ºC for the complete maturation. In addition to the volatile compounds profiles were also evaluated respiration profiles, ethylene production, peel color, quantification of MJ and gene expression of linalool synthase (LIS). Given the importance of linalool to the characteristic aroma papaya, changes in the transcription of a linalool synthase gene were evaluated seeking to correlate them to the treatment effects on the production of volatile compounds. Treatment with MJ influence the production of volatile compounds, particularly linalool and hexanal in the groups kept at 10ºC. Fruits treated with the hormone had higher abundance of the compound when compared to the control group. Although the treatment protocol employee has not been able to recover the high levels found in fruits stored at 22ºC, do not exclude the possibility that other experimental designs can respond even more satisfactorily to this same treatment.

O Glioblastoma é um dos tumores mais agressivos do sistema nervoso central e entre as diversas neoplasias possui um dos piores prognósticos. Mesmo com as novas estratégias de tratamento, a sobrevida de pacientes portadores de glioblastoma continua sendo muito baixa, sendo a temozolomida (TMZ) o agente mais comum usado no seu tratamento. O ácido tetra-o-metil nordihidroguaiarético (M4N), é um novo agente terapêutico que funciona como um repressor transcricional global de genes dependentes do fator de transcrição Sp1, tais como Survivina e Cdk1. No presente estudo, foram investigados os níveis de expressão do gene Survivina, suas variantes gênicas por splicing alternativo e Cdk1 em amostras tumorais e linhagens celulares de GBM. Adicionalmente, foram investigados os efeitos do M4N em combinação ou não com TMZ e/ou radiação em culturas primárias e linhagens celulares de GBM. Ensaios de qRT-PCR foram realizados para determiner a expressão de mRNA das variantes gênicas de Survivina e Cdk1. A proliferação celular foi analisada pelo ensaio XTT e os niveis de apoptose e variações do ciclo celular foram determinados por citometría de fluxo. Analises de combinação de drogas utilizando diferentes estratégias de administração (simultânea e seqüencial) foram realizados baseados no método de Chou-Talalay em linhagens celulares e culturas primárias de GBM. Para os ensaios de sobrevivência clonogênica, foram utilizadas as doses de 2, 4 e 6 Gy de radiação gamma. Todas as variantes por splicing alternativo de Survivina e o gene Cdk1 foram expressos em amostras (n=16) e linhagens celulares (n=6) de GBM, exceto a variante Survivina-2B que apenas foi expressa nas linhagens celulares de GBM. O tratamento com M4N diminuiu a expressão de Cdk1, Survivina e a variante Survivina-Ex3, enquanto que houve um aumento da expressão da variante Survivina-2B. O M4N diminuiu a proliferação celular de forma isolada e sinérgicamente quando combinada com TMZ. Além disso, o M4N aumentou os efeitos da radiação, principalmente quando associado com TMZ. O M4N causou morte celular apoptótica, diminuição do índice mitótico e parada do ciclo celular principalmente na fase x G2/M. Os resultados do presente estudo sugerem a potencial aplicação clínica de M4N em combinação com TMZ e radiação no tratamento do GBM. / Glioblastoma (GBM), one of the most human malignant neoplasia, responds poorly to current treatment modalities, being temozolomide (TMZ) the most used drug in its treatment. TetraO-methyl Nordihydroguaiaretic Acid (M4N) is a global transcriptional repressor of genes dependents of Sp1 transcription factor, such as Survivin and Cdk1. In this study was evaluated the gene expression of Survivin, their spliced-variants and Cdk1 in GBM samples and cell lines. Moreover, it was investigated the effects of M4N combined or not with TMZ and/or radiation on primary cultures and cell lines of GBM. qRT-PCR assays were performed to determine the Survivin-spliced variants and Cdk1 gene mRNA expression in GBM tumor samples and cell lines. Cell proliferation was measured by XTT assay and cell cycle and apoptosis were determined by flow cytometry. Drug combination analyzes using different schedules of administration (simultaneous and sequential) were performed based in ChouTalalay method on GBM cell lines and primary cultures. For clonogenic survival, it was used the doses of 2, 4, and 6 Gy of gamma radiation. All Survivin-spliced variants and Cdk1 gene were expressed in GBM samples (n=16) and cell lines (n=6), except the Survivin-2B variant that was only expressed in GBM cell lines. M4N treatment down regulated the expression of Cdk1, Survivin and Survivin-Ex3 variant, while the Survivin-2B variant was up-regulated. M4N decreased the cell proliferation separately and synergistically with TMZ, moreover it enhanced the radiation effects, mainly when associated with TMZ. M4N also induced apoptotic cell death, decreased mitotic index and arrested the cell cycle mainly in G2/M phase. Our results suggest a potential clinical application of M4N in combination with TMZ and radiation in GB treatment.

Neste estudo foi avaliada a remoção de metil paration - inseticida e atrazina - herbicida presentes em água, em reatores de bancada, com fungos. A pesquisa foi dividida em quatro etapas: operação em batelada com metil paration e micélio fúngico, com e sem glicose; teste de toxicidade em placas com Aspergillus niger AN400; operação em batelada com os pesticidas atrazina e metil paration e esporos de Aspergillus niger AN400, com e sem glicose; e operação em reatores de leito fixo e fluxo ascendente. Na primeira etapa, a remoção de metil paration foi de 97% nos reatores sem glicose e 94% nos reatores com glicose com 32 dias de reação. Na operação em batelada, com esporos, um modelo cinético de primeira ordem representou bem a velocidade de decaimento de metil paration nesta fase, principalmente, nos reatores que continham glicose. Para os experimentos sem adição de glicose, a constante cinética foi de 0,063 &#177 0,005/h, enquanto que para os experimentos com glicose a constante foi de 0,162 &#177 0,014/h. Dessa forma, a adição de glicose resultou efetivamente em aumento na velocidade de conversão do inseticida. Na fase experimental, com atrazina e esporos de Aspergillus niger AN400, a presença do substrato primário (glicose) não teve influência na remoção de atrazina, sendo que os percentuais de remoção foram muito próximos aos percentuais encontrados nos reatores sem glicose. O estudo cinético, nessa fase com atrazina e esporos, revelou que para os experimentos sem a adição de glicose, o valor da velocidade de conversão de atrazina (RATZo) foi de 0,023/d, enquanto que para os experimentos com glicose (RATZo) foi 0,022/d. Portanto, a adição de glicose parece não ter influenciado significativamente a velocidade de remoção do herbicida por Aspergillus niger AN400. O teste de toxicidade demonstrou que metil paration e atrazina não inibiram o crescimento do fungo nas várias concentrações testadas, inclusive nas mais elevadas, que foram 60 mg/L e 25 mg/L para metil paration e atrazina, respectivamente. No reator de leito fixo a remoção de metil paration foi de 40% com 12 h de tempo de detenção hidráulica, e 0,5 g glicose/L. Porém, quando a concentração de glicose foi duplicada a remoção de metil paration diminuiu para 35%. Neste reator o pH se manteve na faixa ácida 3,4 a 5,2, considerada ideal para os fungos. Os resultados encontrados mostram a viabilidade dos fungos para remoção desses pesticidas, considerados persistentes no ambiente. / In this study the removal of methyl parathion was evaluated - insecticide and atrazine - herbicide present in water, in reactors with fungi. The research was divided in four stages: operation in batch reactors with methil parathion and micelium fungus, with and without glucose; toxicity test in plates with Aspergillus niger AN400; operation in batch reactors with the pesticides atrazine and methyl parathion and spore of Aspergillus niger AN400, with and without glucose; and operation in reactors of fixed bed and ascending flow. In the first stage the removal of methyl parathion was 97% in reactors without glucose and 94% in reactors with glucose in 32 days of reaction time. In the operation in batch with spores, a kinetic model of first order represented very well the speed of decline of the methyl parathion in this step, in the reactors that contained glucose, mainly. For the experiments without the glucose addition, the kinetic constant was 0,063 &#177 0,005/h, and for the experiments with glucose the constant was of 0,162 &#177 0,014/h. In that way, the glucose addition resulted in increase in the speed of conversion of the insecticide. In the experimental step with atrazine and spores of Aspergillus niger AN400, the presence of the primary substratum (glucose) didn\'t have influence in the atrazine removal, and the percentile removal lays very close to the percentile found in the reactors without glucose. The kinetic study, in that step with atrazine and spores, revealed that for the experiments without the glucose addition, the value of the speed conversion of atrazine (RATZo) was 0,023/d, and for the experiments with glucose (RATZo) was 0,022/d. Therefore, the glucose addition seems not to have influenced significantly the speed of removal of the herbicide for Aspergillus niger AN400. The toxicity test demonstrated that methyl parathion and atrazine didn\'t inhibit the growth of fungi in the several concentrations, including in high concentrations, that were tested 60 mg/L and 25 mg/L to methyl parathion and atrazine, respectively. The reactor of fixed bed got removal of methyl parathion of 40% in 12 hours of detention hydraulic, in 0,5 g glicose/L. However, when the glucose concentration was doubled the removal of methyl parathion decreased to 35%. In this reactor the pH kept in the acid strip (3,4 - 5,2), considered ideal for the fungi, and conductivity values didn\'t favor the hydrolysis of the insecticide. The found results show the viability of the fungi for removal of those pesticides, considered recalcitrant to the environment.

As propriedades de rugosidade superficial e microdureza são reconhecidas como propriedades muito relevantes no que concerne ao tratamento com prótese total removível, estando associadas ao desgaste da prótese e à sua predisposição à colonização por microrganismos. A proposição deste estudo foi realizar uma análise longitudinal e comparativa, destas duas propriedades, entre uma nova resina acrílica (Vipi Block Gum) para bases de próteses totais removíveis, implementada na tecnologia CAD-CAM, e duas resinas acrílicas termopolimerizáveis, sendo uma convencional (Vipi Cril Plus) e outra polimerizada por ação de micro-ondas (Vipi Wave), antes e após a aplicação de sucessivos ciclos de envelhecimento térmico por temociclagem, de modo a investigar a existência de uma correlação entre o processo de polimerização e o desempenho do material. Para isto, foram confeccionados um total de 60 corpos de prova com formato quadrangular com dimensões de 12x12x3mm, sendo destinados 20 corpos de prova para cada material. Para cada resina, 10 corpos de prova foram destinados ao teste de microdureza Knoop (KHN) e os outros 10 corpos de prova foram submetidos ao teste de rugosidade superficial (Ra-m). As análises dos corpos de prova, para ambos os experimentos, foram realizadas em quatro estágios distintos. As primeiras leituras foram realizadas após imersão dos materiais em água deionizada a 37ºC durante 24 horas (T1), com subsequentes análises após a aplicação de 500 ciclos (T2), 1000 ciclos (T3) e 3000 ciclos (T4) de termociclagem, com temperaturas de 5ºC a 55ºC com duração de 60 segundos para cada banho. Na avaliação estatística, a comparação das médias entre os grupos de resinas foi realizada com o teste de análise de variância (ANOVA) de um critério sendo, seguido do teste de Tukey. Para a comparação interna de cada grupo, em relação ao estágio de termociclagem, foi utilizado um ANOVA de medidas repetidas. O nível de significância adotado foi de 5%. Não houve diferença estatisticamente significante, na comparação intragrupos e intergrupos, em relação à rugosidade superficial (p>0.05). Na análise comparativa da microdureza entre os grupos, foi observada diferença estatisticamente significante nas análises em T1 e T2, com a resina Vipi Block obtendo valores superiores às outras resinas (p=0.00). Em T3, observou-se uma redução significativa da microdureza de todas as resinas, sendo mais pronunciada na resina Vipi Block Gum, tendo esta sido estatisticamente superior apenas em relação à Vipi Wave (p=0.01). Em T4 foi observado um aumento significativo na resina Vipi Cril Plus, com diferença estatisticamente significante (p>0.05) em relação às outras resinas. Na análise interna de cada grupo, foram observadas interações estatisticamente significantes em todas as resinas (p<0.05). A resina Vipi Block Gum teve sua microdureza drasticamente reduzida em T3, mantendo-se similar em T4, sendo significativamente inferiores (p<0.05) aos valores obtidos em T1 e T2. A resina Vipi Cril Plus sofreu uma acentuada redução na comparação em T1 em relação a T3 (p=0.021). Em T4, tornou-se estatisticamente superior a todos os outros períodos (p<0.05). A resina Vipi Wave sofreu redução significativa de T2 para T3 (p=0.01). Semelhantemente, obteve um aumento em T4, tornando-se estatisticamente superior a T3 (p=0.01). / Superficial roughness and microhardness are considered as extremely relevant properties which directly affects treatments with complete removable dentures, being them related to wear, and to the vulnerability of these prostheses to be colonized by microorganisms. The objective of this study was to perform a longitudinal analysis of these properties, making a comparison between a new CAD-CAM denture base acrylic resin (Vipi Block Gum), a conventional heat-polymerized and a microwave-polymerized resins, before and after the application of successive thermocycling cicles, in order to investigate a possible higher performance presented by the Vipi Block Gum resin. Sixty quadrangular shaped specimens with dimensions of 12x12x3mm were made and were equally divided between the three resins. For each material, 10 specimens were destined to the surface roughness analysis (Ra-m) and the other 10, for the Knoop microhardness (KHN) evaluation. The firsts analyses were performed after a 24-hour period of immersion in distilled water at 37ºC (T1), with subsequent analyses after 500 cicles (T2), 1000 cicles (T3) and 3000 cicles (T4) of thermocycling, with temperatures ranging from 5ºC to 55ºC and with 60 seconds of immersion, for each temperature. The statistical analysis, for the intergroup comparison, was done by applying a one-way analysis of variance (ANOVA) test, seconded by Tukeys posthoc test. For the intragroup analysis, a repeated measures ANOVA was applied. A significance level of 5% was adopted for both analyses. There were no significant differences for both intragroup and intergroup comparisons concerning the superficial roughness (p>0.05). The intergroup microhardness analyses showed significant differences at T1 and T2 (p=0.00), with higher values presented by the Vipi Block Gum resin when compared to the other groups. At T3, it was noticed a significant reduction for all materials, although it was more pronounced in the Vipi Block Gum resin, with this group having higher values than the Vipi Wave group (p=0.01). The comparison at T4 showed significant higher values presented by the Vipi Cril Plus in relation to the other groups (p<0.05). The intragroup analyses exhibited statistical significant differences for all materials (p<0.05). Vipi Block Gum resin suffered a significant decrease on its microhardness at T3, which remained similar at T4. However, these values were significant below (p<0.05) the ones obtained at T1 and T2. Vipi Cril Plus group showed a significant decrease at T3 in comparison with T1 (p=0.021). However, it increased significantly at T4 having statistical higher values than all other periods (p<0.05). Vipi Wave group suffered an expressive decrease at T3 in comparison with T2 (p=0.01). It also had an increase on its microhardness at T4, with statistical higher values than the ones observed at T3 (p=0.01).

La carence précoce en donneurs de méthyles (folates et vitamine B12) entraîne une hyperhomocystéinémie ainsi que des troubles cognitifs et de la coordination motrice chez les ratons de 21 jours. Ces troubles ont été reliés à une altération de la neurogenèse dans l'hippocampe et le cervelet, mécanisme étroitement relié à la neurostéroïdogenèse (NSG), définie par la synthèse locale de stéroïdes dans le cerveau. L'objectif principal de ce travail a été de déterminer si ces troubles étaient associés à une altération de la NSG. Ce travail a conduit à plusieurs résultats marquants, montrant notamment l'effet délétère de la carence gestationnelle en donneurs de méthyles sur la voie stéroïdogénique dans le cervelet, région cérébrale particulièrement vulnérable en période post-natale. Ceci s'est traduit par un effondrement du contenu en estradiol et autres neurostéroïdes, consécutivement à la diminution de l'expression de StAR, TSPO et de l'aromatase, ainsi que des récepteurs aux estrogènes. Ces effets délétères sont associés à une atteinte de la voie de signalisation dépendante de l'AMPc associée à l'activation du récepteur LHR, et la diminution de facteurs de transcription impliqués dans la régulation des gènes de la NSG, notamment SF-1, dont la présence dans les cellules de Purkinje du cervelet n'avait jamais été décrite auparavant. Cette réponse à la carence se ferait selon un dimorphisme sexuel, puisque seules les jeunes femelles nées de mères carencées étaient affectées. Enfin, ces études ont permis la mise en évidence d'altérations fonctionnelles associées aux dommages cellulaires et moléculaires observés dans les bulbes olfactifs (BO), se traduisant par une diminution des fonctions de la discrimination olfactive. Ceci pourrait contribuer au retard de croissance associé au poids corporel réduit mesuré chez les animaux carencés / Early methyl-donor deficiency (MDD, folate and vitamin B12) produces hyperhomocysteinemia, cognitive and motor disorders in 21 days-old rat pups. These disorders are linked to an alteration of neurogenesis in the cerebellum and the hippocampus, which is closely linked to neurosteroidogenesis, defined as the local synthesis of steroids in brain. The aim of this work was to verify if these troubles are associated with an altered neurosteroidogenesis. This work led to several striking results, showing in particular the deleterious effects of the methyl donor deficiency on the steroidogenic pathway in the cerebellum, particularly vulnerable during postnatal development. This was confirmed by the reduced contents of estradiol and other neurosteroids, as a result of the decrease of the expression of StAR, TSPO and aromatase, as well as the estrogen receptors. These deleterious effects are associated to the impairment of AMPc dependent signaling pathway and the decrease of transcription factors, notably SF-1, which the presence in the cerebellar Purkinje cells had never been described previously. This response to the deficiency would be made according to a sexual dimorphism, since only the young deficient females were affected. Finally, these studies allowed us to show functional changes associated with the cellular and molecular damage observed in the olfactory bulbs, being traduced by a decrease of the olfactory discrimination. This could contribute to the growth retardation associated with the reduced body weight of the deficient animals