In vitro screening of probiotic lactic acid bacteria and prebiotic glucooligosaccharides to select effective synbiotics

Probiotics and prebiotics have been demonstrated to positively modulate the intestinal microflora and could promote host health. Although some studies have been performed on combinations of probiotics and prebiotics, constituting synbiotics, results on the synergistic effects tend to be discordant in the published works. The first aim of our study was to screen some lactic acid bacteria on the basis of probiotic characteristics (resistance to intestinal conditions, inhibition of pathogenic strains). Bifidobacterium was the most resistant genus whereas Lactobacillus farciminis was strongly inhibited. The inhibitory effect on pathogen growth was strain dependent but lactobacilli were the most effective, especially L. farciminis. The second aim of the work was to select glucooligosaccharides for their ability to support the growth of the probiotics tested. We demonstrated the selective fermentability of oligodextran and oligoalternan by probiotic bacteria, especially the bifidobacteria, for shorter degrees of polymerisation and absence of metabolism by pathogenic bacteria. Thus, the observed characteristics confer potential prebiotic properties on these glucooligosaccharides, to be further confirmed in vivo, and suggest some possible applications in synbiotic combinations with the selected probiotics. Furthermore, the distinctive patterns of the different genera suggest a combination of lactobacilli and bifidobacteria with complementary probiotic effects in addition to the prebiotic ones. These associations should be further evaluated for their synbiotic effects through in vitro and in vivo models

Destin et mémoire des tsiganes dans l\u27Europe nazie (1933-1945)

Cette recherche bibliographique présente un aperçu des études historiques existantes, évoquant le génocide, souvent oublié, des Tsiganes, organisé sous le régime des Nazis. Elle met en évidence également la volonté actuelle de diffuser la mémoire de ce peuple persécuté. Ce travail se partage en trois chapitres : une analyse méthodologique, une synthèse critique des principales recherches, réalisées à ce jour, et une bibliographie organisée

Les élections présidentielles de 2007 à Timor Leste

En avril-mai 2007 des élections présidentielles se sont tenues à Timor-Est. Ce pays, indépendant depuis mai 2002, a connu une série de crises au cours des dernières années, qui a abouti à une remise en question du rôle dominant du Fretilin, le parti historique de la lutte contre l'invasion indonésienne et pour l'indépendance, au pouvoir depuis 2002. Le premier tour a été serré avec trois candidats entre 19 et 28%. Au deuxième tour, qui opposait Lu-Olo, candidat du Fretilin à José Ramos Horta, ancien Premier ministre, co-lauréat du Prix Nobel de la Paix, c'est ce dernier qui a finalement été élu avec 69 % des suffrages. Les élections législatives qui se sont tenues le mois suivant, en juin, ont confirmé l'affaiblissement du Fretilin et le rééquilibrage politique.In April-May 2007 presidential elections were held in East-Timor. Since independence (2002), the country crossed several crisis, calling into question the leading role of the Fretilin, the historical party which fought against Indonesia invasion and for independance. The first round of the ballot was tight with three candidates between 19 and 28%. At the end of the second round, opposing Lu-Olo, Fretilin's candidate to José Ramos Horta, former Prime minister, co-Nobel Peace Laureate in 1996, this last has been elected with 69% of the votes. The legislative elections which were held the following month, in June, confirmed the Fretilin weakening and the political rebalancing.Em abril-maio de 2007 havia eleições presidenciais em Timor Leste. Independente desde maio de 2002, o país conheceu uma série de crises no decorrer destes últimos anos, que acabaram por abalar o papel dominante da Fretilin, partido histórico da luta contra a invasão indonésia e pela independência. A primeira volta foi apertada, com três candidatos obtendo entre 19 e 28% dos votos. Na segunda volta, que opunha Lu-Olo, candidato do Fretilin, a José Ramos Horta, ex-Primeiro ministro, co-laureado do Prémio Nobel da Paz, este ùltimo acabou por ser eleito com 69% dos votos. As eleições legislativas que se realizaram no mês seguinte, em Junho, confirmaram o enfraquecimento da Fretilin e o reequilíbrio político

Assessing the conformational changes of pb5, the receptor-binding protein of phage T5, upon binding to its Escherichia coli receptor FhuA

Within tailed bacteriophages, interaction of the receptor-binding protein (RBP) with the target cell triggers viral DNA ejection into the host cytoplasm. In the case of phage T5, the RBP pb5 and the receptor FhuA, an outer membrane protein of Escherichia coli, have been identified. Here, we use small angle neutron scattering and electron microscopy to investigate the FhuA-pb5 complex. Specific deuteration of one of the partners allows the complete masking in small angle neutron scattering of the surfactant and unlabeled proteins when the complex is solubilized in the fluorinated surfactant F6-DigluM. Thus, individual structures within a membrane protein complex can be described. The solution structure of FhuA agrees with its crystal structure; that of pb5 shows an elongated shape. Neither displays significant conformational changes upon interaction. The mechanism of signal transduction within phage T5 thus appears different from that of phages binding cell wall saccharides, for which structural information is available

PHYTOCHEMISTRY AND BIOLOGICAL ACTIVITIES OF CRATEVA ADANSONII EXTRACTS

Objective: This study aims to search the secondary metabolites of Crateva adansonii (leaves and bark) and evaluate some biological activities (antimicrobial, antioxidant and cytotoxicity's property) of these extracts.Methods: The phytochemical screening was made with standard method. Agar diffusion method was used for antibacterial activity coupled with Minimum Inhibitory Concentration (MIC) and Bactericidal (MBC) determination. The antifungal test was performed by the mycelial development reduction method. DPPH method was used to evaluate the extracts antioxidant activity. Artemia salina larvae were use as support to evaluate the toxicity of the extracts.Results: The results of the phytochemical screening reveal the presence of polyphenols, triterpenoids, and glycosides in the both organs (leaves and bark) of C. adansonii. All the extracts have low activity on the reference strains with a larger diameter of 17±00 mm (S. oralis). Only the ethanolic and hydroethanolic leaf's extracts inhibited respectively 20% and 10%, of the clinical strain S. aureus. The ethyl acetate leaf's extract shows the best antifungal activity (89,19%) with A. clavatus. All extracts present dose-dependent antiradical properties and are non-toxic for the cells of Artemia salina. C. adansonii bark extracts had the best reducing power (23,80±0, 137 mmol/g EqAA EAA) of the DPPH radical.Conclusion: C. adansonii is therefore an active principle source for the development of drugs to antimicrobial and antioxidant activitie

Standing variation and new mutations both contribute to a fast response to selection for flowering time in maize inbreds

<p>Abstract</p> <p>Background</p> <p>In order to investigate the rate and limits of the response to selection from highly inbred genetic material and evaluate the respective contribution of standing variation and new mutations, we conducted a divergent selection experiment from maize inbred lines in open-field conditions during 7 years. Two maize commercial seed lots considered as inbred lines, <it>F</it>252 and <it>MBS</it>847, constituted two biological replicates of the experiment. In each replicate, we derived an Early and a Late population by selecting and selfing the earliest and the latest individuals, respectively, to produce the next generation.</p> <p>Results</p> <p>All populations, except the Early <it>MBS</it>847, responded to selection despite a short number of generations and a small effective population size. Part of the response can be attributed to standing genetic variation in the initial seed lot. Indeed, we identified one polymorphism initially segregating in the <it>F</it>252 seed lot at a candidate locus for flowering time, which explained 35% of the trait variation within the Late <it>F</it>252 population. However, the model that best explained our data takes into account both residual polymorphism in the initial seed lots and a constant input of heritable genetic variation by new (epi)mutations. Under this model, values of mutational heritability range from 0.013 to 0.025, and stand as an upper bound compare to what is reported in other species.</p> <p>Conclusions</p> <p>Our study reports a long-term divergent selection experiment for a complex trait, flowering time, conducted on maize in open-field conditions. Starting from a highly inbred material, we created within a few generations populations that strikingly differ from the initial seed lot for flowering time while preserving most of the phenotypic characteristics of the initial inbred. Such material is unique for studying the dynamics of the response to selection and its determinants. In addition to the fixation of a standing beneficial mutation associated with a large phenotypic effect, a constant input of genetic variance by new mutations has likely contributed to the response. We discuss our results in the context of the evolution and mutational dynamics of populations characterized by a small effective population size.</p

An Inquiry into the Efficacy of a Complementary Training Session for Telephone Survey Interviewers

Un examen de l’efficacité de la formation complémentaire pour les interviewers d’enquêtes téléphoniques : Cet article présente une expérience faite à l’agence d’enquêtes responsable pour l’enquête canadiennne de 2004 sur la consommation de drogues (N=14.000) après une courte séance de formation cognitive. Un total de 79 intervieweurs y ont participé représentant 2.436 journées-intervieweur de travail, avec des intervieweurs travaillant un maximum de 65 jours : l'enquête de terrain a duré 109 jours. Nous avons conçu une séance d’une heure centrée sur l’acquisition des connaissances dans deux secteurs : l'échantillonnage et la sélection dans le foyer d'une part, et les raisons de refus d'autre part. L’évolution quotidienne des performances des intervieweurs, dont les trajectoires basés sur des groupes ont été analysées, nous ont permis d’identifier les intervieweurs à performances basses (n=25) et hautes (n=42) deux semaines avant la formation. La séance de formation était à l’intention des intervieweurs à performances basses ou des nouveaux intervieweurs. Parmi ces intervieweurs, tous ceux qui travaillaient le jour de la séance (n=18) ont participé à l'une des trois séances de formation. Les retombées de la formation ont été évaluées dans trois secteurs : connaissances acquises et attitudes (via une questionnaires rempli deux semaines plus tard), rétention de connaissances et performances. Les résultats montrent pour les intervieweurs participants (a) qu’ils trouvaient que la formation les avaient aidés à comprendre l’échantillonnage et les raisons de refus, (b) qu'ils sentaient plus que les intervieweurs à hautes performances que leur performances s'étaient améliorées depuis le début du projet, (c) qu'ils avaient tendance à continuer plus longtemps à travailler sur les projet qu’un groupe de contrôle, et (d) qu'ils ont amélioré leur performance de .04 par jour après la formation, par rapport à.015 par jour avant la formation, atteignant presque la performance des intervieweurs à hautes performanceThis article presents an experiment in which a short cognitive training session was given at the private pollster conducting the 2004 Canadian Addiction Survey of 14,000 people. Overall, 79 interviewers worked on the project for a total of 2,436 interviewer-days, interviewers worked a maximum of 65 days, and the survey was in the field for 109 days. We devised a one-hour training session that focused on knowledge acquisition in two areas: sampling and selection within household, and reasons for refusals. The evolution of interviewers’ daily performance, analyzed using group-based trajectory analysis, allowed us to identify low (n=25) and high (n=42) performers two weeks before training. The training session was aimed at low performers and newly hired interviewers. Among these, all the interviewers working on training day (n=18) attended one of the three training sessions. The impact of the training was assessed in three areas: knowledge acquisition and attitudes (through a post-training questionnaire two weeks later), retention, and performance. The results show that trained interviewers a) felt that the training helped them understand sampling and the reasons for refusals b) were more likely than high performers to feel that their performance had improved since the beginning of the project, c) were likely to go on working on the project after training longer than the control group, and d) improved their performance by .04 per day after training, compared with .015 per day before training, almost reaching the performance of high performers

Pyrethroid insecticide exposure and cognitive developmental disabilities in children: The PELAGIE mother–child cohort

International audiencePyrethroid insecticides are widely used in agriculture and in homes. Despite the neurotoxicity of these insecticides at high doses, few studies have examined whether lower-level exposures could adversely affect children's neurodevelopment. The PELAGIE cohort included 3421 pregnant women from Brittany, France between 2002 and 2006. When their children reached their sixth birthday, 428 mothers from the cohort were randomly selected, successfully contacted and found eligible. A total of 287 (67%) mothers agreed to participate with their children in the neuropsychological follow-up. Two cognitive domains were assessed by the Wechsler Intelligence Scale for Children: verbal comprehension and working memory. Five pyrethroid and two organophosphate insecticide metabolites were measured in maternal and child first-void urine samples collected between 6 and 19 gestational weeks and at 6 years of age, respectively. Linear regression models were used to estimate associations between cognitive scores and urinary pyrethroid metabolite concentrations, adjusting for organophosphate metabolite concentrations and potential confounders. Maternal prenatal pyrethroid metabolite concentrations were not consistently associated with any children's cognitive scores. By contrast, childhood 3-PBA and cis-DBCA concentrations were both negatively associated with verbal comprehension scores (P-trend = 0.04 and P-trend &lt; 0.01, respectively) and with working memory scores (P-trend = 0.05 and P-trend &lt; 0.01, respectively). No associations were observed for the three other childhood pyrethroid metabolite concentrations (4-F-3-PBA, cis-DCCA, and trans-DCCA). Low-level childhood exposures to deltamethrin (as cis-DBCA is its principal and selective metabolite), in particular, and to pyrethroid insecticides, in general (as reflected in levels of the 3-PBA metabolite) may negatively affect neurocognitive development by 6 years of age. Whatever their etiology, these cognitive deficits may be of importance educationally, because cognitive impairments in children interfere with learning and social development. Potential causes that can be prevented are of paramount public health importanc

Qualification sanitaire des troupeaux, représentations du risque selon les acteurs et les disciplines

La qualification sanitaire vise à établir de manière objective et fiable le statut sanitaire d'un animal ou d'un ensemble d'animaux au regard d'une maladie infectieuse. Concevoir une qualification sanitaire repose sur des connaissances biologiques concernant l'agent pathogène, ses voies de transmission et les moyens de détection de la maladie. Les modèles mathématiques et les outils statistiques et probabilistes permettent d'intégrer ces connaissances tout en prenant en compte l'incertitude et la variabilité des données biologiques. Les sciences humaines apportent un éclairage sur les enjeux, les perceptions et les logiques des individus et des collectifs, afin d'étudier la demande et l'acceptabilité de la qualification sanitaire. Chaque discipline apporte ainsi son point de vue sur la notion de risque sous-jacente à la démarche de qualification. Cette approche interdisciplinaire nécessite une coconstruction de la recherche, qui doit dépasser les différences culturelles et épistémologiques entre disciplines. Elle n'obéit pas à un seul type de rationalité, scientifique ou juridico-administrative ; elle mobilise nécessairement des connaissances savantes et des savoirs empiriques et dépend de nombreuses décisions pouvant engendrer convergences ou contradictions. (Résumé d'auteur