Evaluation of a Hydrogel-Based Diagnostic Approach for the Point-of-Care Based Detection of Neisseria gonorrhoeae

Eleven primer pairs were developed for the identification of Neisseria gonorrhoeae. The sensitivity and specificity of these primers were evaluated by Real Time (RT)-PCR melt curve analyses with DNA from 145 N. gonorrhoeae isolates and 40 other Neisseria or non-Neisseria species. Three primer pairs were further evaluated in a hydrogel-based RT-PCR detection platform, using DNA extracted from 50 N. gonorrhoeae cultures. We observed 100% sensitivity and specificity in the hydrogel assay, confirming its potential as a point-of-care test (POCT) for N. gonorrhoeae diagnosis

Identification d'un conservateur antimicrobien optimal pour une solution protéinique injectable

Un médicament vétérinaire destiné aux animaux de rente en format multi-doses est techniquement facile à utiliser et économiquement avantageux pour les éleveurs et vétérinaires. Dans une solution injectable multidoses, l'inclusion d'un conservateur antimicrobien est requise dans la formule pour prévenir le risque de prolifération microbienne en cas de contamination, si la solution ne possède pas par elle-même ces propriétés. L'enjeu de cette étude a été de trouver un conservateur à large spectre efficace à pH 7, compatible avec le principe actif protéinique et les composés de la formule. Deux formules actuellement commercialisées issues des médicaments à usage humain sont utilisées pour la conservation et l'administration de protéines équivalentes. Une sélection d'agents antimicrobiens compatibles a été testée dans ces deux formules: le chlorocrésol, le chlorure de benzéthonium, le phénoxyethanol et l'alcool benzylique. L'EDTA a été associé au chlorure de benzéthonium et au phénoxyéthanol afin d'évaluer un possible effet synergique. L'efficacité de ces conservateurs a été testée avec des concentrations hautes classiquement utilisées. Le phénoxyéthanol à la concentration de 1 % dans l'une des deux formules a présenté une efficacité conforme aux critères d'acceptabilité des pharmacopées européenne et américaine.ROUEN-BU Médecine-Pharmacie (765402102) / SudocSudocFranceF

Evolutionary reconstruction of pattern formation in 98 <i>Dictyostelium</i> species reveals that cell-type specialization by lateral inhibition is a derived trait

BACKGROUND: Multicellularity provides organisms with opportunities for cell-type specialization, but requires novel mechanisms to position correct proportions of different cell types throughout the organism. Dictyostelid social amoebas display an early form of multicellularity, where amoebas aggregate to form fruiting bodies, which contain only spores or up to four additional cell-types. These cell types will form the stalk and support structures for the stalk and spore head. Phylogenetic inference subdivides Dictyostelia into four major groups, with the model organism D. discoideum residing in group 4. In D. discoideum differentiation of its five cell types is dominated by lateral inhibition-type mechanisms that trigger scattered cell differentiation, with tissue patterns being formed by cell sorting. RESULTS: To reconstruct the evolution of pattern formation in Dictyostelia, we used cell-type specific antibodies and promoter-reporter fusion constructs to investigate pattern formation in 98 species that represent all groupings. Our results indicate that in all early diverging Dictyostelia and most members of groups 1–3, cells differentiate into maximally two cell types, prestalk and prespore cells, with pattern formation being dominated by position-dependent transdifferentiation of prespore cells into prestalk cells. In clade 2A, prestalk and stalk cell differentiation are lost and the prespore cells construct an acellular stalk. Group 4 species set aside correct proportions of prestalk and prespore cells early in development, and differentiate into up to three more supporting cell types. CONCLUSIONS: Our experiments show that positional transdifferentiation is the ancestral mode of pattern formation in Dictyostelia. The early specification of a prestalk population equal to the number of stalk cells is a derived trait that emerged in group 4 and a few late diverging species in the other groups. Group 4 spore masses are larger than those of other groups and the differentiation of supporting cell types by lateral inhibition may have facilitated this increase in size. The signal DIF-1, which is secreted by prespore cells, triggers differentiation of supporting cell types. The synthesis and degradation of DIF-1 were shown to be restricted to group 4. This suggests that the emergence of DIF-1 signalling caused increased cell-type specialization in this group. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2041-9139-5-34) contains supplementary material, which is available to authorized users

Analysis of phenotypic evolution in Dictyostelia highlights developmental plasticity as a likely consequence of colonial multicellularity

Colony formation was the first step towards evolution of multicellularity in many macroscopic organisms. Dictyostelid social amoebas have used this strategy for over 600 Myr to form fruiting structures of increasing complexity. To understand in which order multicellular complexity evolved, we measured 24 phenotypic characters over 99 dictyostelid species. Using phylogenetic comparative methods, we show that the last common ancestor (LCA) of Dictyostelia probably erected small fruiting structures directly from aggre- gates. It secreted cAMP to coordinate fruiting body morphogenesis, and another compound to mediate aggregation. This phenotype persisted up to the LCAs of three of the four major groups of Dictyostelia. The group 4 LCA co-opted cAMP for aggregation and evolved much larger fruiting structures. However, it lost encystation, the survival strategy of solitary amoebas that is retained by many species in groups 1–3. Large structures, phototropism and a migrating intermediate ‘slug’ stage coevolved as evolutionary novelties within most groups. Overall, dictyostelids show considerable plasticity in the size and shape of multicellular structures, both within and between species. This probably reflects constraints placed by colonial life on develop- mental control mechanisms, which, depending on local cell density, need to direct from 10 to a million cells into forming a functional fructificationPeer reviewe

Evaluation of a Hydrogel-Based Diagnostic Approach for the Point-of-Care Based Detection of Neisseria gonorrhoeae

Eleven primer pairs were developed for the identification of Neisseria gonorrhoeae. The sensitivity and specificity of these primers were evaluated by Real Time (RT)-PCR melt curve analyses with DNA from 145 N. gonorrhoeae isolates and 40 other Neisseria or non-Neisseria species. Three primer pairs were further evaluated in a hydrogel-based RT-PCR detection platform, using DNA extracted from 50 N. gonorrhoeae cultures. We observed 100% sensitivity and specificity in the hydrogel assay, confirming its potential as a point-of-care test (POCT) for N. gonorrhoeae diagnosis