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La carpe est le premier poisson de pisciculture à Madagascar ; sa population est issue d'introductions dont la première date de 1912. Partant d'un souci de recenser les ressources génétiques actuelles de cette espèce d'élevage au niveau national, des poissons de plusieurs bassins versants du milieu naturel et d'éleveurs variés ont été analysés. En parallèle, les producteurs d'alevins ont été enquêtés afin de comprendre si leurs pratiques étaient susceptibles d'avoir conservé des populations avec des caractéristiques spécifiques. Ce travail montre que la présentation habituelle des différentes variétés ne résiste pas à l'analyse génétique. Un réseau très actif d'écloseries incluant de nombreux producteurs de taille variable et donc un très grand nombre de géniteurs s'est montré en capacité d'entretenir une souche avec une bonne potentialité. Ce vaste réseau de producteurs d'alevins, de tailles différentes, constitue une ressource précieuse pour le développement de cet élevage qu'il convient de mettre en valeur. Les résultats obtenus sur le tilapia sont présentés en parallèle soulignant l'intérêt de s'interroger sur les ressources génétiques présentes.

The research’s objective is doing an empirical test toward research conducted by Menon & Lukas (2004), which generates 6 propositions of antecedent and outcome factors in the velocity of new product development. The literature theory based on theory of new product development speed (PDS) with antecendent and outcome factors. The research towards 63 respondent managers of Small and Medium Enterprises (SME) companies in Jabodetabek, Indonesia. Six propositions are developed into 6 hypotheses, which are then subject to a statistical test using LVS. Goodness-of-fit test informs that 6 hypotheses are eligible and so does the Measurement-fit test. Test towards 6 hypotheses using significance level of 0.05 with t value of > 1.96 confirms that the data support 5 hypotheses, except for hypothesis number 6 which states that Product Development Speed has no influence on the Orga - nizational Stress. The results provide managerial, theoretical insight and implication that are useful for New Product Development Speed.

In the tilapia species group, the major sex determining factors have been located on Linkage Group 1 (LG1), on a small chromosome (Chr) pair in Oreochromis niloticus, on LG3 (the largest Chr pair) in O. aureus or on both, depending on populations/strains. LG3 has all the traits of an old sex chromosome, whereas LG1 seems to be an emerging one. Taking advantage of its large size, LG3-Chr has been microdissected to search for sex-linked genes. It was isolated from metaphase spreads of XX-female and YY-male in O. niloticus and of ZZ-male in O. aureus. Using cDNA capture and direct cDNA selection procedures we isolated various transposons but a reduced number of genes. We therefore compared three different whole genomic amplification (WGA) methods (DOP-PCR, GenomePlex and GenomiPhi) using a pool of 30 microdissected chromosomes, to evaluate the best LG3-Chr representation. Loci from 5 microsatellites, 2 genes and 2 uncoded fragments located on LG3-Chr have been searched by PCR on the DNA obtained by the 3 methods. GenomePlex and GenomiPhi gave 60 % loci amplification. GenomePlex probe produced the best painting probe, entirely covering the two LG3-Chrs with weaker signals in the gene-rich pericentromeric region, in both species, confirming that this pair is essentially composed of conserved and specific repeated sequences. This will allow to trace its history within the tilapia group. (Texte intégral)

To face the pressure of competition, more and more companies perform accelerated product development by shortening the product development time so that the product will arrive at the market at the shortest time. Food industry has also performed accelerated product development. Using evolution theory, contingency theory, market-based view, and resource-based view a research model has been built. Results of the research’s initial identification show that food industry in Indonesia is in growth level towards maturity level. Meanwhile, competition in the food industry is in moderate level towards hypercompetition level. Tactics of accelerated product development often carried out is by simplifying the product development steps to eliminating the product development steps. The innovation type used is incremental innovation since it is fast and easy. Results of the research give information that intuition and capabilities are the main motivating factors for big-medium scaled food companies in Indonesia to accelerate product development.

The aims of the present study were to develop non-lethal methods to identify individual fish larvae and post-larvae before tagging and accurately follow their growth characteristics. European sea bass (Dicentrarchus labrax) was used as a model species at four different ages ranging from 71 to 100 days post fertilization (dpf). Two different methods were tested for non-lethal tissue sampling from each larva for DNA analysis: 1) using a sterile absorbent paper to sample mucus and/or epithelial cells by rubbing the fish skin and 2) fin-clip of the bottom part of the caudal fin. Whatever the age of the larvae, the genotyping rate (at 12 microsatellite markers) was low with the use of sterile absorbent paper but relatively high with fin-clip sampling at 80 and 87 dpf (on average 17 and 63% of the loci genotyped for sterile paper and fin clips, respectively). Several measurements were performed on digital pictures of sea bass larvae to model body weight. Using area, perimeter, length, height and volume, it was possible to estimate body weight with a coefficient of determination r(2) = 0.98 on very small larvae (body weight ranging from 20.0 to 419.3 mg). The present results suggested that individual monitoring of the growth of European sea bass larvae can be achieved by combining image analysis and microsatellite genotyping as early as 87 dpf or 236 mg mean body weight.

The present study aimed to develop nondestructive methods to accurately follow the growth of fish larvae and post-larvae. European sea bass (Dicentrarchus labrax) aged 71-100 days post fertilization (dpf; 20-419 mg) and Nile tilapia (Oreochromis niloticus) aged 14 dpf (10-25 mg) were used as model species. Several measurements were performed on digital pictures of larvae to model body weight. Using body surface area, contour, length and depth, it was possible to estimate accurately the body weight of young European sea bass and Nile tilapia (r² of 0.98 and 0.95, respectively).

Gastrointestinal infections remain a frequent disease worldwide. In order to increase our knowledge of the epidemiology for our patient population, we retrospectively analyzed the results obtained for stool samples received at the clinical microbiology laboratory of the University Hospital of Geneva during a 4-year period. A total of 13,965 specimens from 7,124 patients (1.96 specimens per patient) were cultured, yielding 369 (2.6%) Salmonella spp., 408 (2.9%) Campylobacter spp., and 79 (0.6%) Shigella spp. The cumulative positivity rate of 6.1% decreased to 2.7% when patients received antimicrobial agents (P < 0.001). The positivity rate for 5,912 specimens obtained from patients hospitalized for < or = 3 days was 12.6%, whereas it dropped to 1.4% for patients hospitalized for > 3 days (P < 0.001). Of 3,837 stool samples originating from pediatric patients, 8.8% were positive, and 5.1% of 10,128 samples from adults were positive (P < 0.001). The cytotoxin of Clostridium difficile was detected in 379 of 3,723 samples analyzed (10.2%), and rotaviruses were detected in 190 of 1,601 samples (11.9%). We recommend that the use of cultures for enteric bacterial pathogens be restricted to patients hospitalized for < or = 3 days, with the exceptions of follow-up samples, specimens from immunocompromised patients, and patients whose first sample was culture negative or in the rare event of nosocomial food-borne outbreaks. For patients under antimicrobial therapy, testing for cytotoxin of C. difficile should primarily be requested; this analysis should also be accepted for samples from patients not receiving antimicrobial agents at the time of specimen collection. By applying these restrictions, we could have saved at least $5,000 annually.

Nile tilapia has primarily a XX/XY sex determining system but minor genetic factors as well as temperature can override the major factors. Female XX progenies can be sex-reversed into functional males by rearing at high temperatures (>34 °C) from 10 dpf onwards. Temperature effects on the molecular pathways during sex differentiation in teleosts need to be deciphered. The temporal expression profiles of cyp19a1a and foxl2, two ovarian-developmental genes and dmrt1 and amh, two testes-developmental genes were analysed during key stages of the sex differentiation of genetic all-females, all-males and temperature-masculinised XX females (TM) tilapia. Overall QPCR analysis was similar between gonads and trunks. Both amh and dmrt1 expressions were up-regulated simultaneously in TM already at 13-15 dpf. Dmrt1 expression became markedly elevated ?3-fold higher than XY male levels at 20-26 dpf whereas amh had similar levels to XY males. Foxl2 and cyp19a1a expression profiles were similar. Both were up-regulated at early stages in TM but repressed after 17-19 dpf, whilest levels continued to increase in XX-females. Our results show that temperature action on tilapia testis development induces the rapid increase of both dmrt1 and amh expressions followed by the down-regulation of foxl2 and cyp19a1a. This suggests that dmrt1 and/or amh may be the modulator(s) of the down-regulation of foxl2 and/or cyp19a1a.

Background The Nile tilapia (Oreochromis niloticus) is the second most farmed fish species worldwide. It is also an important model for studies of fish physiology, particularly because of its broad tolerance to an array of environments. It is a good model to study evolutionary mechanisms in vertebrates, because of its close relationship to haplochromine cichlids, which have undergone rapid speciation in East Africa. The existing genomic resources for Nile tilapia include a genetic map, BAC end sequences and ESTs, but comparative genome analysis and maps of quantitative trait loci (QTL) are still limited. Results We have constructed a high-resolution radiation hybrid (RH) panel for the Nile tilapia and genotyped 1358 markers consisting of 850 genes, 82 markers corresponding to BAC end sequences, 154 microsatellites and 272 single nucleotide polymorphisms (SNPs). From these, 1296 markers could be associated in 81 RH groups, while 62 were not linked. The total size of the RH map is 34,084 cR3500 and 937,310 kb. It covers 88% of the entire genome with an estimated inter-marker distance of 742 Kb. Mapping of microsatellites enabled integration to the genetic map. We have merged LG8 and LG24 into a single linkage group, and confirmed that LG16-LG21 are also merged. The orientation and association of RH groups to each chromosome and LG was confirmed by chromosomal in situ hybridizations (FISH) of 55 BACs. Fifty RH groups were localized on the 22 chromosomes while 31 remained small orphan groups. Synteny relationships were determined between Nile tilapia, stickleback, medaka and pufferfish. Conclusion The RH map and associated FISH map provide a valuable gene-ordered resource for gene mapping and QTL studies. All genetic linkage groups with their corresponding RH groups now have a corresponding chromosome which can be identified in the karyotype. Placement of conserved segments indicated that multiple inter-chromosomal rearrangements have occurred between Nile tilapia and the other model fishes. These maps represent a valuable resource for organizing the forthcoming genome sequence of Nile tilapia, and provide a foundation for evolutionary studies of East African cichlid fishes.

To determine their ability to detect blood-borne pathogens, the blood culture media BCB Release (Becton Dickinson, USA) and Signal (Oxoid, UK) were evaluated on a total of 5,122 blood culture sets. Each of the two bottles was inoculated with an equal amount of blood from 2,262 patients at bedside (2.3 cultures per patient). In the laboratory, agar-coated paddles were attached to the BCB Release bottles and the Signal device was mounted onto the Signal bottles. Both systems were incubated at 35 degrees C for seven days. A total of 608 (11.9%) sets were positive, from which 549 pathogenic microorganisms could be isolated. These could be grown significantly (p0.0001) more often from the BCB Release broth (n = 483) than from the Signal system (n = 384). Mainly staphylococci, Escherichia coli and yeasts were isolated more often from the BCB Release, anaerobes were more often detected from the Oxoid Signal. The time to positivity was significantly shorter (p0.0001) with the BCB Release. The Signal system proved a valuable complement to the BCB Release broth.

Anti-müllerian hormone (AMH) is expressed in male embryos and represses development of müllerian ducts during testis differentiation in mammals, birds and reptiles. Amh orthologues have been identified in teleosts despite them lacking müllerian ducts. Previously we found sexually dimorphic aromatase activity in tilapia brains before ovarian differentiation. This prompted us to search for further dimorphisms in tilapia brains during sex differentiation and see whether amh is expressed. We cloned the tilapia amh gene and found that it contains 7 exons but no spliced forms. The putative protein presents highest homologies with Amh proteins of pejerrey and medaka as compared to other Perciformes. We analysed amh expression in adult tissues and found elevated levels in testes, ovary and brain. Amh expression was dimorphic with higher levels in XY male brains at 10–15 dpf, when the gonads were still undifferentiated and gonadal amh was not dimorphic. Male brains had 2.7-fold higher amh expression than gonads. Thereafter, amh levels decreased in the brain while they were up-regulated in differentiating testes. Our study indicates that amh is transcribed in male brains already at 10 dpf, suggesting that sexual differentiation may be occurring earlier in tilapia brain than in gonads. Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Anti-müllerian hormone (AMH) is expressed in male embryos and represses development of müllerian ducts during testis differentiation in mammals, birds and reptiles. Amh orthologues have been identified in teleosts despite them lacking müllerian ducts. Previously we found sexually dimorphic aromatase activity in tilapia brains before ovarian differentiation. This prompted us to search for further dimorphisms in tilapia brains during sex differentiation and see whether amh is expressed. We cloned the tilapia amh gene and found that it contains 7 exons but no spliced forms. The putative protein presents highest homologies with Amh proteins of pejerrey and medaka as compared to other Perciformes. We analysed amh expression in adult tissues and found elevated levels in testes, ovary and brain. Amh expression was dimorphic with higher levels in XY male brains at 10-15 dpf, when the gonads were still undifferentiated and gonadal amh was not dimorphic. Male brains had 2.7-fold higher amh expression than gonads. Thereafter, amh levels decreased in the brain while they were up-regulated in differentiating testes. Our study indicates that amh is transcribed in male brains already at 10 dpf, suggesting that sexual differentiation may be occurring earlier in tilapia brain than in gonads.

Background Large collections of expressed sequence tags (ESTs) are a fundamental resource for analysis of gene expression and annotation of genome sequences. We generated 116,899 ESTs from 17 normalized and two non-normalized cDNA libraries representing 16 tissues from tilapia, a cichlid fish widely used in aquaculture and biological research. Results The ESTs were assembled into 20,190 contigs and 36,028 singletons for a total of 56,218 unique sequences and a total assembled length of 35,168,415 bp. Over the whole project, a unique sequence was discovered for every 2.079 sequence reads. 17,722 (31.5%) of these unique sequences had significant BLAST hits (e-value < 10-10) to the UniProt database. Conclusion Normalization of the cDNA pools with double-stranded nuclease allowed us to efficiently sequence a large collection of ESTs. These sequences are an important resource for studies of gene expression, comparative mapping and annotation of the forthcoming tilapia genome sequence.

National audience; Les tilapias constituent d’excellents modèles pour l’étude de l’évolution du déterminisme du sexe et la différenciation des chromosomes. Des données récentes suggèrent que ce groupe d’espèces, se trouve à une période charnière de substitution d’une grande paire de chromosomes sexuels ZZ/ZW (Oreochromis aureus) par une petite paire, XX/XY (O. niloticus) via l’émergence d’un facteur mineur devenant progressivement le nouveau déterminant du sexe. En effet, à partir de la carte génétique d’O. niloticus, 2 groupes de liaison, LG1 et LG3, fortement liés au sexe, ont été identifiés chez le tilapia. Chez O. aureus, LG3, localisé par FISH sur la grande paire de chromosomes contient le déterminant majeur du sexe et LG1, localisé sur une petite paire, peut contenir, chez certaines familles/populations, un déterminant mineur du sexe. Inversement, chez O. niloticus, LG3 ne joue plus qu’un rôle mineur dans le déterminisme du sexe, alors que LG1 contient le déterminant majeur. Leurs structures (suppression de recombinaison, accumulation de séquences.répétées / rétrotransposons), suggèrent que ce sont respectivement un vieux et un jeune chromosomes sexuels. En s’appuyant sur des génotypes sexuels spécifiques (mâles et femelles XX, XY, et YY disponibles chez O. niloticus; mâles et femelles ZZ, ZW et femelles gynogénétiques WW à produire chez O. aureus), notre projet multi équipes (CIRAD-CNRS-INRA) cherche à isoler, par microdissection classique ou laser, les 4 paires de chromosomes sexuels des tilapias (X, Y, Z et W). La stratégie consiste à hybrider une source contenant une large quantité de gènes (ADNc) sur des préparations métaphasiques puis à microdisséquer les chromosome d’intérêt, après marquage par un BAC spécifique. Sur chacun de ces chromosomes microdisséqués et amplifiés par PCR, une hybridation directe des ADNc sera ensuite réalisée .afin d’identifier et d’isoler les gènes qui s’hybrident sur chacune des paires de chromosomes sexuels. Les gènes ainsi identifiés seront hybridés sur une banque de BACs et les BACs contenant ces gènes réhybridés sur les chromosomes de chaque génotype pour un ultime contrôle de leur localisation. Les équipes de cytogénétique impliquées dans le projet expliquent ici à quelles étapes elles interviennent (préparations chromosomiques, FISH, microdissection) quelle est leur contribution dans ce projet et quelles sont leurs stratégies pour surmonter les problèmes techniques posés.

Within the tilapia group, the sex determining locus has been located on linkage group 1 (LG1) in Oreochromis niloticus, whereas in O. aureus both LG1 and LG3 are sex-linked. Using specific BAC clones as probes for FISH, LG3 and LG1 have been located on the largest and on a smaller chromosome pair, respectively. The largest pair presents various traits of a relatively old sex chromosome, whereas LG1 seems to be at an early stage of sex chromosome evolution. Evidence for interactions between the two sex linked loci has been demonstrated at least in O. aureus , with minor factors (genetic and environmental factors) also modulating sex ratios. We have taken advantage of the 13-fold larger size of one of the chromosome chromosome pairs to microdissect it in order to search for genes specific to this large pair. This chromosome was microdissected from metaphase preparations of homogametic genotypes (XX and YY for O. niloticus, and ZZ for O. aureus). Microdissected chromosomes were amplified by DOP-PCR and the DOP-products were then used to screen a gonadal cDNA library. Positive clones were hybridized by FISH on metaphase spreads of different genotypes from both species. We evidenced positive signals located on the large chromosomes of both strands indicating specificity of the probes, despite the presence of large amounts of repetitive sequences on these large sex chromosomes. The conservation of the structure of the large pair between the two species is discussed. (Texte intégral)

Sarotherodon melanotheron is one of the most euryhaline teleosts able to withstand variations in environmental salinity ranging from freshwater (FW) to 130%0 hyper-saline waters (HSW). Although significant progress has been made in exploring the cellular and molecular changes that accompany salinity adaptation in teleosts, little is known about the effects of long-term acclimation to HSW. We sought to identify in this tilapia species the genes whose transcription is induced by long-term acclimation either to HSW or FW. Two subtractive cDNA libraries were made from gills of fish acclimated for 45 days to either condition, with 320 partial cDNA sequences encoding proteins potentially involved in the response to the two salinity extremes. The ESTs comparisons with genomic databases allowed putative functions to be attributed to 197 of these genes. The suppression subtractive hybridisation (SSH) results were validated by Real-time PCR for 13 candidate genes having presumably a role in osmoregulation, supplemented by Na+, K+- ATPase a-subunit and carbonic anhydrase, two genes known to be implicated in this function. In fish acclimated to both salinity extremes, the functional category of cellular process was the predominant one, which may indicate high cellular turnover rates in FW and HSW-adapted fish. The acclimation to FW and HSW also appeared to trigger the expression of genes involved in transport activity, biological regulation and metabolic processes, at a higher level in fish acclimated to HSW, suggesting higher metabolic activity in this situation. These results are a first step towards the identification of key molecular processes involved in the fish acclimation to extreme salinities. (Resume d'auteur)

We identified DNA markers linked to sex determining genes in six closely related species of tilapiine fishes. The mode of sex determination differed among species. In Oreochromis karongae and Tilapia mariae the sex-determining locus is on linkage group (LG) 3 and the female is heterogametic (WZ-ZZ system). In O. niloticus and T. zillii the sex-determining locus is on LG1 and the male is heterogametic (XX-XY system). A more complex pattern was observed in O. aureus and O. mossambicus, in which markers on both LG1 and LG3 were associated with sex. We found evidence for sex-linked lethal effects on LG1, as well as interactions between loci in the two linkage groups. Comparison of genetic and physical maps demonstrated a broad region of recombination suppression harboring the sex-determining locus on LG3. Sex-specific recombination suppression was found in the female heterogametic sex. Sequence analysis showed the accumulation of repetitive elements in this region. Phylogenetic analysis suggests that at least two transitions in the mode of sex determination have occurred in this clade. This variation in sex determination mechanisms among closely related species makes tilapias an excellent model system for studying the evolution of sex chromosomes in vertebrates.

Sex in the Nile tilapia, Oreochromis niloticus, is governed by the interactions between a complex genetic sex determination system and the influence of temperature. High temperatures applied during a critical period of sex differentiation can induce masculinisation in some progenies originating from both domestic and wild stocks. Differences in thermo-sensitivity were observed between the wild populations and both paternal and maternal effects have been demonstrated, suggesting that it is a heritable trait. This has been confirmed by the development of divergent lines for thermo-sensitivity. Two thermo-sensitive divergent lines were selected with regard to their sex ratios showing high (=90% males) and low responses (only 54%) when treated at 36°C temperatures. At least one of the mechanisms by which temperature exerts its effects on sex differentiation is through a downregulation of aromatase Cyp19. Expression profiles were analysed in monosex XX populations treated at 27°C and 36°C temperatures showing that temperature up-regulates Sox9s, Amh, IGFs, Dax1 and down-regulates other genes such as aromatase Cyp19-1a. Variation in these gene expression levels was associated with the percentage of males obtained by temperature treatments. The divergent thermo-sensitive lines have been used to complement our study done on the monosex populations. Expression of Cyp19-1a was also analysed in these two divergent lines. (Texte intégral)

Cichlid fish of the Tilapia group are an ideal model for studying sex determination. Sequencing of the Tilapia (Oreochromis niloticus) genome has started in USA and France and genetic and physical linkage maps based on high resolution fingerprints of BAC clones are produced. We have in charge the chromosomal anchoring of some sex linked BACs from the genetic mapping. Some BAC libraries constructed from a male O. niloticus have been assembled into a physical map. Generally, species with a major sex determination locus on linkage group 1 (LG1) are male heterogametic and species with a major sex determination locus on linkage group 3 (LG3) are female heterogametic. In order to confirm that LG1 and LG3 are on two different, unlinked chromosomes, we physically mapped the sex-linked markers by chromosomal FISH on the chromosomes of two closely related Tilapia species, O. niloticus and O. aureus. These experiments demonstrated that LG3 corresponds to the largest chromosome in the Tilapia karyotype, and that LG1 corresponds to a different, smaller chromosome. The chromosome pair corresponding to LG3 in O. niloticus has been manually microdissected and a series of cDNAs isolated from this microdissected product have been cloned, sequenced and selected for chromosomal FISH. Their hybridization helps to validate the results. (Texte intégral)

International audience; UDPGDH (UDP-D-glucose dehydrogenase) oxidizes UDP-Glc (UDP-D-glucose) to UDP-GlcA (UDP-D-glucuronate), the precursor of UDP-D-xylose and UDP-L-arabinose, major cell wall polysaccharide precursors. Maize (Zea mays L.) has at least two putative UDPGDH genes (A and B), according to sequence similarity to a soya bean UDPGDH gene. The predicted maize amino acid sequences have 95% similarity to that of soya bean. Maize mutants with a Mu-element insertion in UDPGDH-A or UDPGDH-B were isolated (udpgdh-A1 and udpgdh-B1 respectively) and studied for changes in wall polysaccharide biosynthesis. The udpgdh-A1 and udpgdh-B1 homozygotes showed no visible phenotype but exhibited 90 and 60-70% less UDPGDH activity respectively than wild-types in a radiochemical assay with 30 microM UDP-glucose. Ethanol dehydrogenase (ADH) activity varied independently of UDPGDH activity, supporting the hypothesis that ADH and UDPGDH activities are due to different enzymes in maize. When extracts from wild-types and udpgdh-A1 homozygotes were assayed with increasing concentrations of UDP-Glc, at least two isoforms of UDPGDH were detected, having K(m) values of approx. 380 and 950 microM for UDP-Glc. Leaf and stem non-cellulosic polysaccharides had lower Ara/Gal and Xyl/Gal ratios in udpgdh-A1 homozygotes than in wild-types, whereas udpgdh-B1 homozygotes exhibited more variability among individual plants, suggesting that UDPGDH-A activity has a more important role than UDPGDH-B in UDP-GlcA synthesis. The fact that mutation of a UDPGDH gene interferes with polysaccharide synthesis suggests a greater importance for the sugar nucleotide oxidation pathway than for the myo-inositol pathway in UDP-GlcA biosynthesis during post-germinative growth of maize.

A rapid procedure was developed for detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) directly from sterile sites or mixed flora samples (e.g., nose or inguinal swabs). After a rapid conditioning of samples, the method consists of two main steps: (i) immunomagnetic enrichment in S. aureus and (ii) amplification-detection profile on DNA extracts using multiplex quantitative PCR (5′-exonuclease qPCR, TaqMan). The triplex qPCR assay measures simultaneously the following targets: (i) mecA gene, conferring methicillin resistance, common to both S. aureus and Staphylococcus epidermidis ; (ii) femA gene from S. aureus ; and (iii) femA gene from S. epidermidis. This quantitative approach allows discrimination of the origin of the measured mecA signal. qPCR data were calibrated using two reference strains (MRSA and methicillin-resistant S. epidermidis ) processed in parallel to clinical samples. This 96-well format assay allowed analysis of 30 swab samples per run and detection of the presence of MRSA with exquisite sensitivity compared to optimal culture-based techniques. The complete protocol may provide results in less than 6 h (while standard procedure needs 2 to 3 days), thus allowing prompt and cost-effective implementation of contact precautions.

Lors de la régénération des premiers vitroplants obtenus par embryogenèse somatique chez le palmier à huile, on a observé l'apparition d'une anomalie florale qui pourrait être induite par un stress lors de la culture #in vitro#. Des travaux effectués sur d'autres espèces végétales ont mis en évidence que l'acide 2,4-D apporté dans les milieux de culture à certaines étapes du processus d'embryogenèse somatique pourrait être à l'origine de l'apparition de variants somaclonaux. D'autres études laissent à supposer que le 2,4-D aurait une action sur le degré de méthylation de façon indirecte via la teneur en cytokinines endogènes. Au cours de ce travail, on a étudié l'effet de différentes concentrations de 2,4-D apportées au stade suspensions cellulaires, sur les teneurs en cytokinines endogènes à 2 stades de culture. Une technique de quantification hormonale a été adaptée pour permettre le dosage des différentes formes hormonales (2,4-D et cytokinines de formes zéatine et isopentényladénine) au sein d'un même extrait végétal et appliquée sur des échantillons de palmier à huile pour doser leurs teneurs en 2,4-D et en cytokinines. Les résultats obtenus montrent que les cytokinines sont absentes au stade de prolifération cellulaire (qui contient du 2,4-D dans les milieux de culture), alors que des traces allant de 0,2 à 0,6 pmol/mg MF sont détectées au stade pro-embryons (qui ne contient pas de 2,4-D dans les milieux de culture). Par ailleurs, il a été constaté que le 2,4-D est accumulé dans les tissus végétaux aux deux stades étudiés (avec des teneurs allant de 1,6 à 10,9 pmol/ mg MF). Enfin, les dosages obtenus indiquent une plus faible accumulation du 2,4-D au stade pro-embryons par rapport au stade suspensions cellulaires, ce qui permet de faire l'hypothèse d'une action du 2,4-D sur la concentration en cytokinines endogènes dans les tissus végétaux

The BACTEC 9240 (Becton Dickinson, Sparks, Md.) automated blood culture system is based on the continuous monitoring of CO2 production by means of a fluorescent sensor attached to the bottom of a culture vial. We compared two media for this system, resin-containing Plus aerobic/F and Lytic anaerobic/F. Sets of Plus aerobic/F and Lytic anaerobic/F vials inoculated with similar volumes (9 +/- 2.5 ml) were evaluated. In the laboratory, the vials were introduced into the system in accordance with the recommendations of the manufacturer and incubated at 35 degrees C for 5 days. A total of 10,914 sets consisting of two bottles each were obtained from 3,674 patients (2.97 cultures per patient). Of these, 1,233 (11%) were culture positive, including 1,074 (10%) yielding at least one pathogen, and 178 (2%) were contaminated. A total of 1,135 isolates were considered clinically relevant in 624 septic episodes; we isolated 894 from Plus aerobic/F and 852 from Lytic anaerobic/F (P = 0.06 [not significant]). More S. aureus isolates (P = 0.05), Pseudomonas spp. (P < 0.0001), other gram-negative bacteria (P = 0.004), and yeasts (P < 0.0001) were isolated from Plus aerobic/F medium, but more streptococci (P < 0.0001), E. coli (P = 0.02) strains and anaerobes (P < 0.0001) were detected with Lytic anaerobic/F medium. Lytic anaerobic/F vials were significantly (P < 0.0001) more often positive at least 6 h before Plus aerobic/F vials (n = 112 versus 52, respectively). Significantly more (P < 0.0001) Plus aerobic/F vials (n = 210; 1.9%) than Lytic anaerobic/F vials (n = 42; 0.4%) were unconfirmed positives. Plus aerobic/F and Lytic anaerobic/F proved to be a valuable pair of blood culture media. Plus aerobic/F performs better for patients under antibiotic treatment, due to the antimicrobial-neutralizing effect of resins. For patients without antibiotic therapy, more microorganisms could be isolated from Lytic anaerobic/F due to cell lysis.

The BACTEC 9240 (Becton Dickinson, Sparks, Md.) automated blood culture system is based on the continuous monitoring of CO2 production by means of a fluorescent sensor attached to the bottom of culture vials. We compared the performance of the BACTEC aerobic Plus/F medium to that of the Septi-Chek Release medium (Becton Dickinson, Sparks, Md.), a manual biphasic blood culture system. Sets consisting of BACTEC aerobic Plus/F and Septi-Chek Release vials inoculated with similar volumes (7 +/- 2 ml) were evaluated. In the laboratory, systems were equipped and analyzed according to the manufacturer's recommendations. The BACTEC and Septi-Chek vials were incubated at 35 degrees C for 5 days. A total of 6,116 compliant sets were obtained from 1,972 adult patients (3.1 cultures per patient). Of these, 731 (12%) were culture positive, including 612 (10%) that yielded at least one pathogen, and 143 (2%) were considered to be contaminated. Of the 672 pathogenic organisms detected, 524 were isolated from the BACTEC aerobic Plus/F medium and 574 were isolated from the Septi-Chek Release medium, 428 organisms grew in both media, 96 organisms grew only in the BACTEC aerobic Plus/F medium, and 146 organisms grew only in the Septi-Chek Release medium (P = 0.001). Haemophilus spp. were isolated more often (P = 0.03) from the BACTEC aerobic Plus/F medium; however, more Streptococcus anginosus organisms (P = 0.02), members of the Enterobacteriaceae family (P < 0.03), and gram-negative anaerobes (P = 0.03) were isolated from the Septi-Chek Release medium. Pathogenic organisms were detected significantly earlier (P < 0.0001) with the BACTEC aerobic Plus/F medium in conjunction with the BACTEC 9240 instrument than with the Septi-Chek Release medium.

The BacT/Alert (Organon Teknika Corp., Durham, N.C.) is an automated blood culture system. It is based on the detection of CO2 by means of a colorimetric sensor internally attached to the bottom of culture bottles. The aerobic and anaerobic media of this system were compared with one bottle of the Signal system (Oxoid Ltd., Hampshire, United Kingdom). At bedside, 20 ml of blood was drawn from each adult patient. The two BacT/Alert bottles were inoculated with 5 ml of blood each; the Signal bottle was inoculated with 10 ml. A total of 5,284 sets (2,483 patients; 2.1 cultures per patient) consisting of three bottles each were evaluated, of which 781 sets (14.8%) revealed microorganisms (n = 892); 642 of these were considered to be pathogenic. Significantly more (P < 0.0001) pathogens were isolated from the two BacT/Alert bottles together (n = 584) than from the single Signal bottle (n = 515). Escherichia coli (P = 0.007), gram-negative bacteria other than members of the family Enterobacteriaceae or Pseudomonas spp. (P = 0.006), and yeasts (P = 0.02) were isolated more often from both or either BacT/Alert bottle. Comparing the systems in terms of 388 different organisms per septic episode, the difference between BacT/Alert and Signal was significant for the total number of septicemia cases (P = 0.003). More contaminants grew in the BacT/Alert system (173 versus 116; P = 0.0001). False-positive indications were more frequent in the BacT/Alert system, 198 (3.7%) aerobic bottles and 57 (1.1%) anaerobic bottles, than in the Signal bottles, 24 (0.5%) bottles. Pathogens could be detected significantly earlier (P < 0.0001) in the BacT/Alert system than in the Signal system. The BacT/Alert instrument with two bottles allowed earlier detection as well as the isolation of more microorganisms than the manual, one-bottle Signal system.