Étude des déterminants génétiques de la pathogénicité chez les nématodes du genre Globodera

Les nématodes à kyste de la pomme de terre (Globodera rostochiensis et G. pallida) sont des phytoparasites causant des pertes de rendement considérables, évaluées à plus de 9 % de la production mondiale de pomme de terre. Comprendre les éléments génétiques essentiels permettant aux nématodes d’infecter la pomme de terre devrait pouvoir mener à l’élaboration d’une méthode de lutte durable et efficace contre ces nématodes parasites. Pour identifier les éléments génétiques essentiels à l’infection de la pomme de terre, nous avons séquencé leurs transcriptomes, ainsi que ceux d’espèces apparentées, mais incapables de parasiter la pomme de terre, G. tabacum et G. mexicana. En comparant ces deux groupes, nous avons identifié les gènes impliqués dans la spécificité parasitaire pour l’hôte. Près de 25 % des gènes codants pour des effecteurs, des protéines dont le nématode se sert dans différentes étapes du parasitisme, ainsi qu’une multitude de gènes régulateurs ont été trouvés significativement surexprimés chez les deux espèces capables de parasiter la pomme de terre. L’expression de ces gènes était différente lorsque les larves furent exposées à l’exsudat racinaire de tomate, suggérant que le nématode est en mesure d’adapter l’expression de ces gènes effecteurs selon l’hôte par l’entremise des gènes de régulation en réponse au signal chimique de l’exsudat racinaire. Aussi, plusieurs variants non-synonymes communs à chacun des groupes ont été identifiés, ainsi que des gènes non caractérisés uniques aux nématodes à kyste de la pomme de terre, ce qui pourrait contribuer à la capacité de ces nématodes à pouvoir parasiter la pomme de terre. Une comparaison semblable a aussi été réalisée entre différents pathotypes de G. rostochiensis, afin de comprendre la différence de virulence entre ces pathotypes sur les cultivars de pomme de terre possédant le gène de résistance H1. Le gène de résistance H1 est utilisé dans les cultivars, qui sont disponibles commercialement et confère une résistance contre les pathotypes Ro1 et Ro4. Une courte liste de gènes candidats possédant des variants uniques aux pathotypes avirulents, ainsi que des gènes uniques à ces pathotypes ont été identifiés et permettront la validation future du gène d’avirulence, reconnu pas le gène de résistance H1. Étonnamment, les analyses ont permis de montrer que plusieurs gènes d’effecteurs ont un niveau d’expression différent selon le pathotype et corrèle avec le degré de virulence de ces pathotypes. Enfin, l’identification de gènes de référence a dû être réalisée, afin de normaliser les données d’expression obtenues par RT-qPCR. Onze gènes candidats ont été sélectionnés à partir de donnée de séquençage d’ARN et de gènes validés dans d’autres études. Trois gènes de référence ont été sélectionnés basés sur la stabilité de leur expression. Les résultats présentés ici permettent un avancement certain dans la compréhension de la manière dont les nématodes parasites utilisent leurs effecteurs et comment cela leur permet de définir leur gamme d’hôtes. Le but ultime de l’étude des nématodes phytoparasites est le développement d’un moyen de lutte efficace et la compréhension du mécanisme d’infection est une étape préalable pour contrer ce parasite complexe.Potato cyst nematodes (Globodera rostochiensis and G. pallida) are plant parasite causing considerable yield losses, estimated at more than 9% of global potato production. Understanding the genetic characteristics allowing the nematode to infect potato should lead to the development of sustainable and effective control methods against these parasitic nematodes. To identify the genetic elements essential for potato parasitism, I sequenced their transcriptomes, as well as those of related species unable to parasitize potato, G. tabacum and G. mexicana. By finding differences between these two groups, it may be able to identify the genes involved in the specificity of host. Nearly 25% of the genes coding for effectors, proteins used in different stages of parasitism, as well as a multitude of regulatory genes were found to be significantly overexpressed in the two species able to parasitize potato. The expression of these genes was different when the larvae were exposed to tomato root exudate suggesting that the nematode can adapt the expression of these effector genes according to the host through regulatory genes, in response to the chemical signal of the root exudate. Also, several non-synonymous variants common to each group have been identified, as well as uncharacterized genes unique to potato cyst nematodes, which could also contribute to the ability of these nematodes to be able to parasitize potato. A similar comparison was also made between different pathotypes of G. rostochiensis to understand the difference in virulence on potato cultivars carrying the H1 resistance gene. The H1 resistance gene is used in commercially available cultivars, and confers resistance against the Ro1 and Ro4 pathotypes, but remains susceptible to the Ro2, Ro3 and Ro5 pathotypes. A short list of candidate genes with variants unique to avirulent pathotypes, as well as genes unique to these pathotypes, were identified and will allow future validation of the avirulence gene. Surprisingly, gene expression analyzes have shown that the expression of several effector genes has a different expression for each pathotypes and correlates with the degree of virulence of these pathotypes. Finally, the identification of reference genes had to be performed, to normalize the expression data obtained by RT-qPCR. Eleven candidate genes were selected from RNA sequencing data and previously validated reference genes. Three reference genes were selected based on the stability of their expression. The results presented here allow important progress in understanding how parasitic nematode use their effectors and how this allows them to define their host range. The final goal of plant-parasitic nematodes studies is the development of effective control means and the understanding of the mechanism of infection is a preliminary step for this complex parasite

Season of the year influences infection rates following total hip arthroplasty

To research the influence of season of the year on periprosthetic joint infections. METHODS We conducted a retrospective review of the entire Medicare files from 2005 to 2014. Seasons were classified as spring, summer, fall or winter. Regional variations were accounted for by dividing patients into four geographic regions as per the United States Census Bureau (Northeast, Midwest, West and South). Acute postoperative infection and deep periprosthetic infections within 90 d after surgery were tracked. RESULTS In all regions, winter had the highest incidence of periprosthetic infections (mean 0.98%, SD 0.1%) and was significantly higher than other seasons in the Midwest, South and West (P \u3c 0.05 for all) but not the Northeast (P = 0.358). Acute postoperative infection rates were more frequent in the summer and were significantly affected by season of the year in the West. CONCLUSION Season of the year is a risk factor for periprosthetic joint infection following total hip arthroplasty (THA). Understanding the influence of season on outcomes following THA is essential when risk-stratifying patients to optimize outcomes and reduce episode of care costs. © The Author(s) 2017

Hepatocellular carcinoma: a clinicopathological study of 64 cases

Hepatocellular carcinoma (HCC) is the most common of all liver cancers and is a major worldwide public health problem. The aim of this study was to provide an updated overview on clinicopathological features, treatment and outcome of HCC. In our retrospective study, we reviewed 64 cases of HCC that were diagnosed at the pathology department of Mongi Slim hospital over a fifteen-year period (2000- 2014). Relevant clinical information and microscopic slides were retrospectively reviewed. Our study group included 38 men and 26 women (sex ratio M/F = 1,26) aged between 8 and 83 years (mean = 56,64 years). The presenting clinical symptoms were dominated by abdominal pain (n=34), followed by altered general health (n=25) and jaundice (n=4). Fifty-five patients underwent surgical treatment. Liver transplantation was performed in two cases and transarterial chemoembolization was achieved in seven cases. Histopathological examination of the surgical or biopsy specimen established the diagnosis of conventional HCC in 55 cases, fibrolamellar carcinoma in 6 cases and clear cell HCC in 3 cases. Seven patients with HCC died postoperatively. Local recurrence of the tumour occurred in three cases and two patients had distant metastases postoperatively. The other patients are still being followed-up. Hepatocellular carcinoma is associated with a high rate of mortality because of early invasion, widespread metastasis and lack of effective therapeutic modalities. Accurate diagnosis and staging of these tumours is critical for optimal treatment planning and for determining prognosis.Keywords: Liver, hepatocellular carcinoma, cancer, patholog

Impacts environmentaux, toxicité et biodégradation des dégivrants pour avions

Glycol based fluids are used to deice and anti-ice aircraft surfaces before takeoff of airplanes. It is strictly for security purposes that large volumes of aircraft deicers are used at airports. Hundreds of thousands of liters are used every year at small airports and millions of liters in the case of major airports. During deicing or anti-icing activities, an appreciable amount of deicing fluids mix with airport runoffs and finds its way into nearby streams and lakes. The objectives of this research is (1) to determine the role of temperature and initial concentration of deicers on biodegradation process, (2) to evaluate the conditions of biodegradation of deicers in a municipal biological treatment plant, and (3) to study the toxicity of deicers for different aquatic species. Results of the experiments indicate that the biodegradation rate of deicers depends on temperature and the ratio of initial concentration of deicers to microorganisms (C[subscript i]/X[subscript i]). The rate of removal of the deicing chemical follows a first-order model. Degradation rate coefficient (κ) at 20 ± 2 °C varies from 1.6 d[superscript -1] for C[subscript i]/X[subscript i] = 0.7 to 0.07 d[superscript -1] when C[subscript i]/X[subscript i] = 19.5. At a temperature of 10 ± 1°C, κ decreases to 0.72 when C[subscript i]/X[subscript i] = 0.7. No materially different k values κ values (0.05 d[superscript -1]) were recorded for the experiments at 4 ± 1 °C when C[subscript i]/X[subscript i] increased from 1.8 to 3.2. The results obtained suggest that biodegradation of deicers will take place in segments of the streams located far downward the discharge point. However, high concentrations at the discharge point could turn out to be toxic to aquatic biota. It is possible to treat deicing fluids at a municipal biological treatment plant. Biotest shows that deicers were slightly toxic to the microorganisms of activated sludge. The toxic deicer concentration responsible for a 50% reduction of the respiration rate is about 30% in volume. The addition of deicing fluids did not have any impact on the pH of the treatment plant effluent; however it exerts an additional oxygen demand. The presence of deicing fluids in the bioreactor could delay nitrification and, increases the filamentous growth. The injection of deicing fluids did not impair the treatment plant efficiency for BOD[subscript 5], COD and SS removal. Also, values of BOD[subscript 5], SS and phosphorus of the effluent were within the range usually recorded at the treatment plant. Chemical analyses demonstrate that deicing fluids did not have an impact on the dehydrated sludge. Deicers and especially anti-icers are more toxic than pure glycol. Green algae Selenastrum capricornutum turns out to be more sensitive than marine bacteria Photobacterium phosphoreum. Inhibitory concentration IC[subscript 50]-30 min of pure ethylene glycol for Photobacterium phosphoreum is estimated to 84 780 mg/L while IC[subscript 50]-30 min of de-icing fluid UCAR XL 54 and anti-icing fluid UC 5.1 are 25 752 mg/L and 5 425 mg/L respectively. In the case of Selenastrum capricornutum, IC[subscript 50]-96 h of pure ethylene glycol is estimated to 5 412 mg/L. This result is presently used by Environment Canada in the derivation of the water quality guideline on ethylene glycol. Inhibitory concentration IC[subscript 50]-96 h of de-icing fluid UCAR XL 54 and anti-icing fluids UCAR ULTRA and UC 5.1 are 2 575 mg/L, 2 785 mg/L and 41 mg/L respectively

Image in Image Steganography based on modified Advanced Encryption Standard and Lest Significant Bit Algorithms

الستيكانوغرافي هو فن لإخفاء المعلومات او البيانات أو تضمينها في وسائط رقمية مختلفة مثل الصور، الفيديو، الصوت والنصوص. وان هناك الكثير من التقنيات لتحقيق عملية الإخفاء. في هذا البحث قمنا بحماية البيانات أو أي معلومات بطريقتين: التشفير والإخفاء. الغرض الأساسي من البحث هي تقديم طريقة تشفير مطورة للرسالة أولا باستخدام خوارزمية (التشفير القياسي المتقدم)AES   هو تشفير مفتاح متماثل حيث ان لكل شفرة من الشفرات بحجم كتلة 128 بت، حيث ان الأحجام الرئيسية هي  من 128، 192، 256 بت. ثانيا نقوم بإخفاء تلك الرسالة المشفرة في الحدود الخارجية للصورة الملونة (الإطار الخارجي للصورة الغلاف) باستخدام دالة LSB (البت الأقل اهمية) في ملفات الصورة الغلاف التي تكون بامتداد (bmp) أو(Jpeg) علما ان الخوارزمية الأخيرة تتسم بالضعف تجاه الهجمات لذلك تم تطويرها وتدعيمها بخوارزمية AES لزيادة الأمن ضد اي هجوم محتمل اثناء ارسالها عبر شبكة الانترنيت من المرسل الى المستلم.Because the big grown of the digital market and the growing demand for protection to data and information which transmitted through the Internet. Steganography is the art of embedding, hiding information into different digital media, it was the main reason to increase its importance in the exponential development of the secret communication of computer and digital cloud users over the internet. There are a lot of techniques and different ways to achieve hiding data. Usually, the data embedding is obtained in communication such as image, text, voice or any multimedia content for copyright and also in military communication for authentication and many other different purposes. In this paper, we protected the information in two ways: Encryption and Steganography. The basic idea is to present a method that encrypted the message firstly by using The AES (Advanced Encryption Standard) it is a symmetric-key encryption each of these ciphers it has 128-bit the size to block, and size keys of 128, 192 and 256 bits.  Secondly, hide that encrypted message in color cover image in the Least Significant Bit (LSB) to image’s frame with (.bmp, .jpg) extensions. Our scheme is to enhance the ability of LSB algorithm to include the storage of information and images encoded and intangible sense of human vision. That two methods to increased together the security attend any attack

Les enjeux de la diversité : pour une médiation multiculturelle

"Bosou" et "Legba", par Dubréus Lhérisson, présentés à l’exposition Haïti. Deux siècles de création artistique au Grand Palais à Paris du 19 novembre 2014 au 15 février 2015. Auriez-vous reconnu ces sculptures prophylactiques d’inspiration vaudou sans légende, ni cartel ? © Saoussan Sabeh La loi Musée du 4 janvier 2002 fut la première en France à officialiser, légalement parlant, le rôle pédagogique et hédoniste de l’institution muséale. La médiation constitue ce mode de communication spéci..

Extended reach well drilling : master’s thesis

Temeljna svrha izrade horizontalnih (vodoravnih) bušotina, tj. bušotina kojima proizvodni dio kanala zauzima horizontalan položaj u prostoru, jest povećanje dodira kanala bušotine s ležištima nafte i/ili plina, te na taj način povećavanja proizvodnosti tih bušotina. Izrada bušotina velikog dosega postao je čest način izrade bušotine koji omogućava ekonomičan pristup rezervama koje su prethodno bile izvan dohvata, uz postojeću infrastrukturu, i smanjuje utjecaj proizvodnih postrojenja na okoliš. Većina horizontalnih bušotina izrađuju se zbog razrade raspucanih stijena u ležištu, ležišta s potencijalnim problemima konusiranja vode i/ili plina te ležišta s proizvodnim naslagama male debljine. U radu su prikazani primjeri izrade horizontalnih bušotina velikog dosega, oprema koja je pri tom korištena, te problemi koji se javljaju prilikom izrade ovakvih bušotina.Abstract: The main purpose of drilling horizontal wells i.e. wells who's production comes from the horizontal section , it enhances the wellbore kontakt with the reservoir containing oil and/or gas, and by that increasing the production of these wells. Extended-reach drilling (ERD) has become a common means to access reserves economically from existing infrastructure, that were previously out of reach, and reduce the environmental footprint of production facilities. Most of the horizontal wells are drilled to develope the cracked rocks in the reservoir, reservoirs with potential water coning problems and reservoirs with small reservoir production thickness. The paper presents examples of extended reach wells, equipment that was used to drill, and the problems that occur when drilling such wells