Le cancer épithélial de l’ovaire (CEO) est le cancer gynécologique le plus létal. Plus de 70% des patientes diagnostiquées avec une tumeur de stade avancé rechutent suite aux traitements chimiothérapeutiques de première ligne, la survie à cinq ans étant ainsi très faible. Afin de mieux comprendre l’évolution de la maladie, nous avons recherché de nouveaux gènes, responsables de l’initiation et de la progression du CEO. Précédemment, des lignées cellulaires ont été dérivées à partir de la tumeur primaire et récurrente et/ou d’ascites de trois patientes. Le séquençage de l’ARN de ces lignées par la technologie de séquençage de nouvelle génération (TSNG) nous a permis d’identifier des mutations ponctuelles qui pourraient nous indiquer des gènes dérégulés dans le CEO. La TSNG est un bon outil qui permet d’identifier et de cribler à grande échelle des mutations. Nous avons sélectionné PLEC1, SCRIB, NCOR2, SEMA6C, IKBKB, GLCE et ITGAE comme gènes candidats présentant des mutations dans nos lignées et ayant une relation fonctionnelle avérée avec le cancer. Étant donné que la TSNG est une technique à taux de fiabilité limité, nous avons validé ces mutations par séquençage Sanger. Ensuite, nous avons étudié l’effet de ces mutations sur la structure protéique et l’expression de PLEC1, de SCRIB et de SEMA6C. Seules certaines mutations dans les gènes PLEC1, SCRIB et SEMA6C ont pu être confirmées. PLEC1 et SCRIB sont deux protéines d’échafaudage dont la mutation, rapportée dans plusieurs cancers, pourrait induire des changements de leurs conformations et affecter leurs interactions et leurs fonctions. Les conséquences de ces mutations sur la tumorigenèse de l’ovaire devront être étudiées. / Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer. Over 70% of the patients diagnosed with advanced stage of cancer relapse following first-line chemotherapy treatments; consequently the five-year survival is very low. To better understand the evolution of the disease, our aim was to identify new genes responsible for the initiation and progression of EOC. Previously, cell lines derived from solid tumors or ascites were developed from the primary and recurrent tumor or ascites of three patients. RNA sequencing of these cell lines by next-generation sequencing technology (NGST) allowed us to identify mutations that might point to genes whose deregulation is important in EOC. Mutations were detected in PLEC1, SCRIB, NCOR2, SEMA6C, IKBKB, GLCE and ITGAE. We selected these genes for further studies as they have previously been identified as being associated with cancer. First, we validated these mutations by Sanger sequencing in order to determine the concordance with NGST data. Secondly, we studied the impact of the validated mutations on protein structure and gene expression. Only certain mutations in PLEC1, SCRIB and SEMA6C were confirmed. Of interest, PLEC1 and SCRIB are two scaffold proteins, where mutations have been reported in several cancers and, possibly leading to changes in their conformation and thereby affecting their interactions and functions. The consequences of these mutations on ovarian tumorigenesis remain to be determined.

Agricultural management is essential for achieving optimum crop production and maintaining soil quality. Soil microorganisms are responsible for nutrient cycling and are an important consideration for effective soil management. The overall goal of the present research was to better understand microbial communities in agricultural soils as they relate to soil management practices. For this, we evaluated the differential impact of two contrasting drainage practices on microbial community composition and characterized active denitrifiers from selected agricultural sites. Field drainage is important for crop growth in arable soils. Controlled and uncontrolled tile drainage practices maintain water in the field or fully drain it, respectively. Because soil water content influences nutrient concentration, moisture, and oxygen availability, the effects of these two disparate practices on microbial community composition was compared in paired fields that had diverse land management histories. Libraries of the 16S rRNA gene were generated from DNA from 168 soil samples collected from eight fields during the 2012 growing season. Paired-end sequencing using next-generation sequencing was followed by read assembly and multivariate statistical analyses. Results showed that drainage practice exerted no measureable effect on the bacterial communities. However, bacterial communities were impacted by plant cultivar and applied fertilizer, in addition to sampled soil depth. Indicator species were only recovered for depth; plant cultivar or applied fertilizer type had no strong and specific indicator species. Among indicator species for soil depth (30-90 cm) were Chloroflexi (Anaerolineae), Betaproteobacteria (Janthinobacterium, Herminiimonas, Rhodoferax, Polaromonas), Deltaproteobacteria (Anaeromyxobacter, Geobacter), Alphaproteobacteria (Novosphingobium, Rhodobacter), and Actinobacteria (Promicromonospora). Denitrification in agricultural fields transforms nitrogen applied as fertilizer, reduces crop production, and emits N2O, which is a potent greenhouse gas. Agriculture is the highest anthropogenic source of N2O, which underlines the importance of understanding the microbiology of denitrification for reducing greenhouse gas emissions by altered management practices. Existing denitrifier probes and primers are biased due to their development based mostly on sequence information from cultured denitrifiers. To circumvent this limitation, this study investigated active and uncultivated denitrifiers from two agricultural sites in Ottawa, Ontario. Using DNA stable-isotope probing, we enriched nucleic acids from active soil denitrifiers by exposing intact replicate soil cores to NO3- and 13C6-glucose under anoxic conditions using flow-through reactors, with parallel native substrate controls. Spectrophotometric chemistry assays and gas chromatography confirmed active NO3- depletion and N2O production, respectively. Duplicate flow-through reactors were sacrificed after one and four week incubation periods to assess temporal changes due to food web dynamics. Soil DNA was extracted and processed by density gradient ultracentrifugation, followed by fractionation to separate DNA contributed by active denitrifiers (i.e., “heavy” DNA) from that of the background community (i.e., “light” DNA). Light and heavy DNA samples were analyzed by paired-end sequencing of 16S rRNA genes using next-generation sequencing. Multivariate statistics of assembled 16S rRNA genes confirmed unique taxonomic representation in heavy fractions from flow-through reactors fed 13C6-glucose, which exceeded any site-specific or temporal shifts in putative denitrifiers. Based on high relative abundance in heavy DNA, labelled taxa affiliated with the Betaproteobacteria (71%; Janthinobacterium, Acidovorax, Azoarcus, Dechloromonas), Alphaproteobacteria (8%; Rhizobium), Gammaproteobacteria (4%; Pseudomonas), and Actinobacteria (4%; Streptomycetaceae). Metagenomic DNA from the original soil and recovered heavy fractions were subjected to next-generation sequencing and the results demonstrated enrichment of denitrification genes with taxonomic affiliations to Brucella, Ralstonia, and Chromobacterium in heavy fractions of flow-through reactors fed 13C6-glucose. The vast majority of heavy-DNA-associated nitrite-reductase reads annotated to the copper-containing form (nirK), rather than the heme-containing enzyme (nirS). Analysis of recovered nirK genes demonstrated low sequence identity across common primer-binding sites used for the detection and quantification of soil denitrifiers, indicating that these active denitrifiers would not have been detected in molecular surveys of these same soils.

No description available.

La compréhension des mécanismes moléculaires impliqués dans la détermination du sexe chez les plantes à fleurs est primordiale d’un point de vue fondamental et appliqué. Des processus liés à la biosynthèse des hormones, tel que l’éthylène, ou la régulation de l’expression génique via des petits ARN et des facteurs de transcription ont été associés à l’unisexualisation des fleurs chez des espèces dioïques. Cependant, les déterminants contrôlant le sexe chez les plantes sont encore largement méconnus. Le palmier dattier, Phoenix dactylifera L, est une espèce dioïque dont le dimorphisme sexuel est observé très tôt au cours du développement des fleurs. Des gènes différentiellement exprimés (DEGs) ont été identifiés pendant les stades précoces du développement floral mâle et femelle. Pour cela, un transcriptome de référence rassemblant des données d’expression relatives aux deux sexes a été généré. L’analyse d'enrichissement GO des DEGs, a révélé des processus biologiques communs aux mâles et aux femelles, associés au développement reproducteur et à la réponse aux stimuli. Ce résultat indique que des mêmes processus peuvent solliciter des gènes différents au cours du développement floral précoce en fonction du sexe. Cette analyse a également mis en évidence que le développement des fleurs mâles requiert des processus biologiques spécifiques impliqués dans la régulation cellulaire et l'expression des gènes. En outre, deux DEGs femelles, une S-adenosylmethionine synthase et une Flap endonuclease et un DEG mâle, un élément transposable, ont été identifiés dans les régions non-recombinantes du génome du palmier dattier.Cette étude est la première analyse globale des processus biologiques associés à l’acquisition du dimorphisme sexuel. Elle contribue également à la compréhension de la détermination du sexe chez le palmier dattier, et plus largement à la connaissance de ces processus chez les espèces dioïques. / Unraveling molecular mechanisms involved in sex determination in flowering plants is of outstanding basic and applied interest. Several studies on dioecious species have highlighted the molecular basis of sex determination, such as cell death and ethylene biosynthesis pathway. Sex determination mechanisms in plants are, however, still largely unknown. The date palm, Phoenix dactylifera L, is a dioecious species where sexual dimorphism is observed very early in development of flowers. Differentially expressed genes (DEGs) were identified during the early stages of the male and female flower development. A reference transcriptome including male and female data was constructed to gain insight into this process in the dioecious palm Phoenix dactylifera L. Differentially expressed genes (DEG) were subsequently identified between males and females in the early flower development stages in which the first morphological gender difference occurs in date palms.Gene ontology enrichment analysis of DEG revealed biological processes shared between males and females involved in reproductive development and response to stimulus, indicating that same processes could require different genes during early flower development in date palm. This analysis also suggested that date palm triggers biological processes specifically involved in cellular regulation and gene expression to develop male flowers. Furthermore, two female DEGs related to DNA methylation S-adenosylmethionine synthase and DNA metabolism Flap endonuclease, and one male DEGs, a transposable element were found in non-recombinant date palm regions. This study provided the first insight into biological processes involved in sex determination in date palms and more widely to knowledge of this process in dioecious species.

No description available.

No description available.

Nous introduisons un ensemble de modèles à facteurs latents dédié à la génomique du paysage et aux tests d'associations écologiques. Cela comprend des méthodes statistiques pour corriger des effets d'autocorrélation spatiale sur les cartes de composantes principales en génétique des populations (spFA), des méthodes pour estimer rapidement et efficacement les coefficients de métissage individuel à partir de matrices de génotypes de grande taille et évaluer le nombre de populations ancestrales (sNMF) et des méthodes pour identifier les polymorphismes génétiques qui montrent de fortes corrélations avec des gradients environnementaux ou avec des variables utilisées comme des indicateurs pour des pressions écologiques (LFMM). Nous avons aussi développé un ensemble de logiciels libres associés à ces méthodes, basés sur des programmes optimisés en C qui peuvent passer à l'échelle avec la dimension de très grand jeu de données, afin d'effectuer des analyses de structures de population et des cribles génomiques pour l'adaptation locale. / We introduce a set of latent factor models dedicated to landscape genomics and ecological association tests. It includes statistical methods for correcting principal component maps for effects of spatial autocorrelation (spFA); methods for estimating ancestry coefficients from large genotypic matrices and evaluating the number of ancestral populations (sNMF); and methods for identifying genetic polymorphisms that exhibit high correlation with some environmental gradient or with the variables used as proxies for ecological pressures (LFMM). We also developed a set of open source softwares associated with the methods, based on optimized C programs that can scale with the dimension of very large data sets, to run analyses of population structure and genome scans for local adaptation.

Introdução: A variação genética em genes que codificam a absorção, distribuição, metabolismo e excreção (ADME) de medicamentos frequentemente afeta a farmacocinética da droga e resulta na variabilidade da eficácia e segurança do medicamento. No entanto, a frequência da variação genética nos genes ADME diferem entre as populações. O objetivo deste estudo foi analisar as variações genéticas nos genes ADME nos pacientes brasileiros portadores do vírus da hepatite C e comparar com outros bancos de dados (1000 Genomes Project e Exome Aggregation Consortium). Métodos: Um total de 147 genes ADME foram genotipados em 100 amostras por sequenciamento de DNA genômico usando SureSelectXT (Agilent) e MiSeq, NextSeq (Illumina). Resultados: Um total de 2004 SNPs em 147 genes foram analisados, incluindo enzimas de fase I (n=50), enzimas de fase II (n=37) e transportadores (n=60). Uma coleção de variantes genéticas indica que há pelo menos 2 vezes mais variações do que semelhanças entre os pacientes com hepatite C e os principais grupos continentais. Estas diferenças foram observadas em vários genes relevantes, incluindo CYP1A2, CYP3A4, NAT2, ABCB1 e SLCO1B1. Além disso, pacientes auto declarados como branco, pardo, negro e asiático também apresentaram diferenças de frequência alélica quando comparados à europeus, americanos mixos, africanos e asiáticos nos polimorfismos dos genes CYP1A1, CYP2B6, GSTP1 e ABCG2, respectivamente. Conclusão: Concluímos que os pacientes com hepatite C tem uma frequência alélica de genes ADME diferente dos outros bancos de dados. Embora a personalização do tratamento medicamentoso com base no genótipo individual, e não na etnia, possa ser a mais apropriada, as diferenças nas frequências alélicas entre os continentes devem ser consideradas ao projetar ensaios clínicos de novos medicamentos / Background: Genetic variation in genes encoding drug absorption, distribution, metabolism, and excretion (ADME) proteins often affects the drug pharmacokinetics and results in variability in drug efficacy and safety. However, the frequency of genetic variation in the ADME genes differ among populations. The aim of this study was to analyze the genetic variations in the ADME genes in Brazilian patients with hepatitis C and to compare to other databases (1000 Genomes Project e Exome Aggregation Consortium). Methods: A total of 147 ADME were genotyped in 100 samples from Brazil by targeted genomic DNA sequencing using SureSelectXT (Agilent) and MiSeq, NextSeq (Illumina). Results: A total of 2004 SNPs in 147 genes that were analyzed, including phase I enzymes (n=50), phase II enzymes (n=37), drug transporters (n=60). We provide a collection of genetic variants that indicate that there are at least 2-times more variation than similarities between patients with hepatitis C and major continental groups. These differences were observed in several relevant genes including CYP1A2, CYP3A4, NAT2, ABCB1 and SLCO1B1. Moreover, white, brown, black and Asian self-reported patients also showed allele frequency differences when compared to European, mixed American, African and Asian for polymorphisms of the genes CYP1A1, CYP2B6, GSTP1 and ABCG2. respectively. Conclusion: We conclude that the hepatitis C patients has an allele frequency of ADME genes different from other data bases. While personalization of drug treatment based on individual genotype rather than ethnicity may be more appropriate, differences in allelic frequencies across continents should be considered when designing clinical trials of new drugs

INTRODUÇÃO: A microbiota intestinal tem sido alvo de diversos estudos moleculares, principalmente através da introdução de plataformas de sequenciamento de nova geração, devido à sua importância e amplo relacionamento com o hospedeiro humano. Entretanto, o armazenamento de amostras fecais antes da extração do DNA é crítico ao caracterizar a composição da microbiota intestinal. Com base nesses dados, o presente estudo buscou compreender os efeitos de diferentes métodos de armazenamento de amostras fecais para caracterizar a microbiota intestinal através do sequenciamento da nova geração, bem como estabelecer um método alternativo de conservação do material genético bacteriano nessas amostras, utilizando guanidina. MÉTODO: Foram coletadas amostras de fezes de 10 voluntários saudáveis. Cada amostra foi dividida em cinco alíquotas, uma alíquota extraída imediatamente após a coleta (fresca) e duas alíquotas submetidas ao congelamento, à temperaturas de -20°C e -80°C e extraídas após 48 horas. As outras duas alíquotas restantes foram armazenadas em guanidina à temperatura ambiente e a 4°C e extraídas após 48 horas. Para observar a presença de alterações na microbiota intestinal, durante um período de armazenamento maior das amostras de fezes, três amostras foram armazenadas em guanidina à temperatura ambiente e a 4ºC e extraídas após o período de 60 dias. A região hipervariável v4 do gene 16S rRNA bacteriano foi amplificada por PCR. Os amplicons gerados foram sequenciados utilizando a plataforma Ion PGM Torrent e os dados analisados utilizando o software QIIME. A determinação da significância estatística foi realizada utilizando-se o teste não-paramétrico de Kruskal-Wallis. RESULTADOS: Não foram encontradas diferenças significativas em nenhum dos níveis taxonômicos (filo, classe, família, ordem e gênero) entre amostras frescas analisadas e os métodos de armazenamento testados. As análises de coordenadas principais (PCoA) mostraram que as amostras se agruparam de acordo com os indivíduos analisados, tendo as amostras referentes a cada indivíduo agrupado-se com maior proximidade do que com outras amostras do mesmo grupo de armazenamento. CONCLUSÃO: Nossos dados sugerem que o congelamento e o uso de guanidina para armazenamento de amostras de fezes, para a caracterização da microbiota intestinal, podem efetivamente preservar o material genético bacteriano nessas amostras ao longo de um período de 48 horas para amostras submetidas ao congelamento e durante 60 dias para amostras armazenadas em guanidina / INTRODUCTION: The gut microbiota has been the target of several molecular studies, mainly through the introduction of next generation sequencing platforms, due to its importance and wide relationship with the human host. However, the storage of fecal samples prior to DNA extraction is critical when characterizing the composition of the intestinal microbiota. Based on these facts, the present study aimed to understand the effects of different methods of storage of fecal samples to characterize the intestinal microbiota by next generation sequence, as well as establishing an alternative conservation method of the bacterial genetic material in these samples using guanidine. METHODS: Stool samples from 10 healthy volunteers were collected. Each collected sample was divided into five aliquots, one aliquot extracted immediately after collection (fresh) and two aliquots subjected to freezing at -20°C and -80°C temperatures and extracted after 48 hours. The others two remaining aliquots were stored in guanidine at room temperature and at 4°C and extracted after 48 hours. In order to observe the presence of alterations in the intestinal microbiota, during a longer storage period of the stool samples, three samples were stored in guanidine at room temperature and at 4°C and extracted after 60 day period. The v4 hypervariable region of bacterial and archeal 16S rRNA gene were amplified by PCR. The generated amplicons were sequenced using Ion PGM Torrent platform and the data analyzed using the software QIIME. Determination of statistical significance was performed using non-parametric Kruskal-Wallis test. RESULTS: No significant differences were found in any of the taxonomic levels (phylum, class, family, order and genus) between analyzed fresh samples and the others different storage methods. The principal coordinates analysis (PCoA) unweighted showed that the samples clustered based on the host each sample originated from, rather than by storage group. CONCLUSION: Our data suggest that both freezing and the use of guanidine to store stool samples for gut microbiota characterization can effectively preserve the bacterial genetic material in these samples over a 48 hours period for samples subjected to freezing and for up to 60 days for samples stored in guanidine

The present study aimed to evaluate bacterial isolates and the microbiome of dairies. The specific aims were: to characterize Staphylococcus spp. isolated from mastitic milk, to evaluate the presence of Lactococcus in mastitic milk as a potential causative agent of mastitis, to evaluate the association between microbiome and milk quality parameters, and to characterize Staphylococcus spp. isolated from production lines of Minas Frescal cheese. The detection of genes encoding virulence factors (enterotoxins (sea, seb, sec, sed, see, seg, seh, sei, selj, selk, sell, selm, seln, selo, selp, seIq, ser, ses, set, selu, selv, and selx), hemolysins (hla, hlb, hld, hlg, and hlgv), exfoliative toxins (eta, etb, and etd), Panton-Valentine leukocidin (pvl), and toxic shock syndrome toxin (tst)), genes encoding antibiotic resistance (resistance to tetracycline (tetK, tetL, and tetM), erythromycin (ermA, ermB, and ermC), methicillin (mecA and mecC), and tobramycin (ant(4\')-Ia)), molecular typing (spa, SCCmec, and agr types), and phenotyping regarding antibiotic resistance were performed in staphylococci isolates from mastitic milk, and from cheese processing plant samples. Staphylococcus aureus was identified in the majority of isolates from both origins. Several virulence factor genes were detected. The distribution of genes encoding staphylococcal enterotoxins (85.0% - 85.7% of isolates were positive for one or more enterotoxin gene) was highlighted and the gene related to H toxin was the most prevalent. Methicillin-resistant Staphylococcus aureus were identified in isolates from mastitic milk (4.1%) and cheese processing (6.0%); the genotyping and phenotyping of these isolates were described. t605 had the highest frequency in the S. aureus population studied. In mastitic milk, Lactococcus was suggested as the causative agent of an outbreak of mastitis in a dairy farm. Using next generation sequencing, the abundance of Lactococcus was observed in microbiome samples. Bacterial isolation and DNA sequencing confirmed the presence of Lactococcus lactis and Lactococcus garvieae. The microbiome of environmental samples and bulk tank milk from the dairy farm showed the Lactococcus genus among the most common bacterial taxa, suggesting other sources of this genus. Regarding milk quality parameters, the microbiome of bulk tank milk from several dairy farms was associated with somatic cell count and bacterial count. The core microbiome was described and many genera of importance were identified. Among the associations performed between microbiome and milk quality parameters, the identification of Streptococcus in samples classified with high somatic cell count and high bacterial count was highlighted. Several bacterial taxa with relative abundance significantly higher in samples classified as high and low cell count and bacterial count were shown. Real-time polymerase chain reaction was also performed associated with bacterial diversity, bacterial taxa, and bacterial count. These findings highlight the need to control and prevent bacterial contamination in the dairy industry, from herd to consumers. / O presente estudo apresentou como objetivo avaliar isolados bacterianos e microbioma de lácteos. Os objetivos específicos foram: caracterizar Staphylococcus spp. isolados de leite de vacas com mastite, avaliar a presença de Lactococcus em leite de vacas com mastite como um potencial agente causador de mastite, avaliar a associação entre microbioma de leite de tanque e parâmetros da qualidade de leite, e caracterizar Staphylococcus spp. isolados de linhas de processamento de queijo Minas frescal. A detecção de genes codificadores de fatores de virulência (enterotoxinas (sea, seb, sec, sed, see, seg, seh, sei, selj, selk, sell, selm, seln, selo, selp, seIq, ser, ses, set, selu, selv, e selx), hemolisinas (hla, hlb, hld, hlg, e hlgv), toxinas exfoliativas (eta, etb e etd), leucocidina de Panton-Valentine (pvl), toxina da síndrome do choque tóxico (tst)), genes codificadores de resistência a antibióticos (resistência a tetraciclina (tetK, tetL e tetM), eritromicina (ermA, ermB e ermC), meticilina (mecA e mecC) e tobramicina (ant(4\')-Ia)), tipagem molecular (spa, SCCmec e agr types), e fenotipagem quanto à resistência a antibióticos foram realizadas em estafilococos isolados de leite de vacas com mastite e de amostras de planta de processamento de queijo. Staphylococcus aureus foi identificado na maioria dos isolados de ambas as origens. Diversos genes de fatores de virulência foram detectados, com destaque para a distribuição de genes codificadores de enterotoxinas estafilocócicas (85,0%-85,7% dos isolados foram positivos para um ou mais genes codificadores de enterotoxinas), sendo o gene relacionado com a toxina H o mais frequente. Staphylococcus aureus meticilina resistente foram identificados em isolados de leite de vacas com mastite (4.1%) e em processamento de queijo (6.0%); o perfil genotípico e fenotípico destes isolados foram descritos. t605 foi o mais freqüente na população de S. aureus estudada. Em leite de vacas com mastite, Lactococcus foi sugerido como o agente causador de um surto de mastite numa fazenda leiteira. Usando sequenciamento de nova geração, a abundância de Lactococcus foi observada no microbioma das amostras. O isolamento e sequenciamento de DNA confirmaram a presença de Lactococcus lactis e Lactococcus garvieae. O microbioma de amostras ambientais e de leite de tanque da fazenda mostrou o gênero Lactococcus entre os mais comuns, sugerindo outras fontes deste gênero. Contemplando parâmetros da qualidade de leite, o microbioma de leite de tanque de várias fazendas leiteiras foi relacionado com contagem de células somáticas e contagem bacteriana. O core microbiome foi descrito e muitos gêneros bacterianos de importância foram identificados. Dentre as análises realizadas associando microbioma com parâmetros da qualidade de leite, foi destacada a identificação de Streptococcus em amostras classificadas com alta contagem de células somáticas e alta contagem bacteriana. Diversos táxons bacterianos com abundância relativa significativamente maior em amostras classificadas com alta e baixa contagem de células somáticas e contagem bacteriana foram mostrados. Reação em cadeia da polimerase em tempo real também foi realizada e associada com diversidade bacteriana, táxons bacterianos e contagem bacteriana. Estes levantamentos confirmam a necessidade de controlar e prevenir a contaminação bacteriana na indústria de lácteos, do rebanho leiteiro até os consumidores.