Transcriptome response of the Pacific oyster (Crassostrea gigas) to infection with Vibrio tubiashii using cDNA AFLP differential display.

We used qualitative complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) differential display analysis and real-time, quantitative PCR (RT-qPCR) to identify genes in the Pacific oyster Crassostrea gigas, whose transcription either changes in response to exposure to a pathogenic bacterium (Vibrio tubiashii) or varies between families known to differ in sensitivity to heat stress, before and at 12 and 36 h after bacterial exposure at a temperature of 25 degrees C. These conditions simulate those associated with summer mortality syndrome, a poorly understood cause of massive mortalities in cultured Pacific oysters in North America, Asia and Europe. Using 32 AFLP primer pairs, we identified 92 transcript-derived fragments that are qualitatively differentially expressed. We then cloned and sequenced 14 of these fragments, designed fragment-specific primers and quantified their transcription patterns using RT-qPCR. Most of the differences in transcription patterns between stress-tolerant and stress-sensitive families were evident before bacterial exposure, and genes that responded to bacterial exposure did so in parallel between stress-sensitive and stress-tolerant families. Blast searches of sequence databases revealed that these fragments represent genes involved in immune response as well as genes related to metabolic processes. Our data support the hypothesis that family level differences in resistance to stress in Pacific oysters are largely attributable to constitutive differences in gene transcription or 'general vigour' that are detectable before and maintained after infection, rather than being due to induced responses at the transcriptome level.

[Analize of the determinants of microscopy's quality in the context of tuberculosis fighting within the health centers laboratories in Dakar Region]. / Analyse des déterminants de la qualité de la microscopie pour la lutte contre la tuberculose dans les laboratoires des Centres de Santé de la Region de Dakar.

INTRODUCTION: In order to improve the quality of the microscopy in the context of tracking and following-up the pulmonary tuberculosis patients, a study of the determinants of the quality of microscopy was carried out in the laboratories of the health centres in Dakar Region, Senegal. MATERIALS AND METHODS: We did an epidemiologic study, transversal type which proceeded during April 19th at May 05th, 2004. It consisted of a series of observations, interviews, review of the registers of laboratory and with a second reading and re staining, on the level of the National Laboratory of Reference of the National Programme of fight against Tuberculosis (LNR), of 50 blades collected blindly in the health centres of Dakar. RESULTS: It comes out from this study that there was no statistically significant link between the factors of risk of errors such as the overload of work, the bad condition of the microscope, the lack of competence and the errors observed in certain laboratories. On the other hand the aspect of the smears, the thickness of the smears and the presence of crystals could deteriorate the quality of microscopy because it was found that there was a statistically significant connection between the quality of microscopy and these various determinants. In addition we noted a good agreement of the results of these laboratories with those of the LNR (Kappa test = 0,981, p < 0,0001). CONCLUSION: According to these results, we recommend: a reinforcement of competences (training/recycling) regular of the laboratory assistants, and an installation of a system of quality control of microscopy, interns within the laboratories but also external by the National Laboratory of Reference.

[Study of determinants of unprotected sex in sailors of the Senegalese merchant navy]. / Étude des déterminants des rapports sexuels non protégés chez les marins de la marine marchande sénégalaise.

Sailors are a mobile population travelling a lot and therefore being often exposed to casual sex. The aim of this study is to analyze the determinants of unprotected sex among sailors in Senegal. A descriptive and analytical study was conducted among sailors of the merchant navy. Data on knowledge, attitudes and practices were collected during a personal interview. A multivariate analysis was performed using a multiple logistic regression. A total of 400 sailors were interviewed, 57.9% had casual sex of whom 23.7% were not protected. Sexual intercourse without protection was more common among the uneducated (OR = 2.29 [1.23 to 5.99]) and married (OR = 2.29 [1.23-5.99]). Sailors who thought that using condom reduces pleasure during sexual intercourse (OR = 2.5 [1.2-5.1]) and those who consumed alcohol (OR = 5.4 [2.07-14.2]) were less protected during casual sex. Sexual contact is one of the main modes of transmission of HIV / AIDS. Sailors often have unprotected sex. Interventions using specific ways must be performed taking into account the mobility of these men who are often uneducated.