Evolution of Lactococcus lactis phages within a cheese factory

We have sequenced the double-stranded DNA genomes of six lactococcal phages (SL4, CB13, CB14, CB19, CB20, and GR7) from the 936 group that were isolated over a 9-year period from whey samples obtained from a Canadian cheese factory. These six phages infected the same two industrial Lactococcus lactis strains out of 30 tested. The CB14 and GR7 genomes were found to be 100% identical even though they were isolated 14 months apart, indicating that a phage can survive in a cheese plant for more than a year. The other four genomes were related but notably different. The length of the genomes varied from 28,144 to 32,182 bp, and they coded for 51 to 55 open reading frames. All five genomes possessed a 3 overhang cos site that was 11 nucleotides long. Several structural proteins were also identified by nano-high-performance liquid chromatography–tandem mass spectrometry, confirming bioinformatic analyses. Comparative analyses suggested that the most recently isolated phages (CB19 and CB20) were derived, in part, from older phage isolates (CB13 and CB14/GR7). The organization of the five distinct genomes was similar to the previously sequenced lactococcal phage genomes of the 936 group, and from these sequences, a core genome was determined for lactococcal phages of the 936 group

Examen de l'impact de la division du travail sur la performance et de sa pertinence en contexte de vidéosurveillance

Le travail d’équipe est un sujet d’intérêt grandissant et la réalité d’aujourd’hui fait en sorte que le travail d’équipe est omniprésent dans une variété de domaines. Le domaine de la sécurité publique n’en fait pas exception à la règle. Des évènements comme les attentats de la Rambla à Barcelone ou du World Trade Center à New York ont prouvé que la surveillance vidéo est un atout majeur dans le rôle des intervenants en sécurité publique et qu’il est critique d’en comprendre les mécanismes. La réalité sur le terrain est que les pratiques de division des tâches et de travail d’équipe ne sont pas harmonisées en salle de contrôle. Grâce à une tâche de vidéosurveillance simulée en laboratoire à l’aide du micromonde Cognitive Solution to Security Surveillance (CSSS), la présente étude visait dans un premier temps à vérifier si, lorsque comparé au travail individuel, le travail d’équipe a un impact les performances dans un contexte de vidéosurveillance. Dans un deuxième temps, la présente étude visait à comparer l’impact sur la performance de deux stratégies de division des tâches, soit de manière spatiale où chaque surveillant est en charge d’un nombre limité de caméras, soit en prenant en compte les objectifs, où chaque surveillant détient au préalable des objectifs précis de recherche. Les résultats ont révélé que pour une tâche de surveillance donnée, les équipes ont rapporté plus d’incidents que les participants qui ont réalisé la tâche individuellement, mais c’est la stratégie de division des tâches par objectifs qui a rapporté une charge mentale inférieure. Somme toute, l’utilisation de stratégies de division des tâches plus sophistiquées que la division spatiale des secteurs ou des écrans, comme la division des tâches par objectifs, devrait être considérée dans les salles de contrôle afin de répartir la charge de travail de manière plus structurée et ergonomique.Teamwork is a topic of growing interest and is ubiquitous in a variety of fields in today’s reality. Public safety is no exception to the rule. Events such as the Rambla attacks in Barcelona or the World Trade Center in New York have shown that video surveillance is a major asset in the role of responders and that it is critical to further understand human surveillance performance. In relation to teamwork in control rooms, operational procedures and the division of labor are not harmonized. Using a laboratory-simulated video surveillance task within the Cognitive Solution to Security Surveillance (CSSS) microworld, the present study first aimed to verify whether, when compared to individual work, teamwork has an impact on performance. Secondly, the present study aimed to compare the impact of two strategies of division of tasks on performance: Task allocation was either based on the spatial dimension, each operator being in charge of a specific set of cameras, or goal-oriented, each operator receiving specific research objectives beforehand. Results showed that for a given supervisory task, teams detected more incidents than participants who completed the task individually, however, goal-oriented teams reported the lowest mental workload. Overall, the use of more sophisticated strategies than the spatial division of screens, such as goal-oriented strategies, should be considered in control rooms in order to distribute the workload in a more structured and ergonomic way

Estimating pCO2 from remote sensing in the Belgian Coastal Zone

In coastal waters, a purely field observation based approach will probably be insufficient to better constrain estimates of air-sea CO2 fluxes, to study their inter-annual variability and their long-term changes. One approach to achieve these goals is to use remotely sensed fields of relevant biogeochemical variables to extrapolate available data, and produce maps of the partial pressure of CO2 (pCO2) and air-sea CO2 fluxes. In the open ocean this approach has to some extent been successfully used based on fields of chlorophyll-a (Chla) and sea surface temperature (SST). This approach remains challenging in coastal waters that have complex optical properties (Case-II waters) and that exhibit highly dynamic pCO2 temporal and spatial variations. In the frame of the Belgian funded BELCOLOUR-II project (Optical remote sensing of marine, coastal and inland waters; http://www.mumm.ac.be/BELCOLOUR/), three field cruises per year (April, July and September) for optical measurements were carried in 2007, 2008, 2009 in the Southern Bight of the North Sea (SBNS). Based on these data-sets, we derived algorithms to compute pCO2 from Chl-a and sea surface salinity (SSS) using multipolynomial regressions (MPR). Here we report the first application of the MPR algorithms to derive pCO2 fields in the Belgian coastal zone based on data gathered in 2007, using remote sensed Chl-a (MERIS) and SSS computed with a 3-D hydrodynamical model of SBNS (COHERENS).info:eu-repo/semantics/publishe

REGARD PARENTAL SUR LES DEVOIRS ET LES LEÇONS EN FONCTION DES CARACTÉRISTIQUES FAMILIALES ET DU RENDEMENT DE L’ÉLÈVE

L’étude s’intéresse à certains aspects des devoirs et des leçons par l’entremise d’analyses menées à partir de regroupements de familles en fonction de la structure familiale, de la scolarité des parents et du rendement scolaire de l’enfant. L’échantillon est composé de 465 parents d’élèves de 1re et de 4e années du primaire. Les données ont été recueillies à l’aide de questionnaires autoadministrés au cours de la première année de l’étude. Les analyses de comparaison révèlent que les familles non traditionnelles et que les familles dont l’enfant éprouve des difficultés scolaires sont plus rébarbatives aux devoirs et aux leçons. Ces mêmes familles en perçoivent moins l’utilité que les autres. Les familles moins scolarisées et les familles ayant un enfant en difficulté se sentent moins compétentes pour intervenir de manière adéquate dans les devoirs et les leçons. Il appert que les besoins et les limites de ces familles doivent être pris en considération par les enseignants dans le cadre de l’assignation des devoirs et des leçons. Mots clés : devoirs et leçons, caractéristiques familiales, participation des parents, élèves du primaireIn the present study, various aspects of homework were examined in a sample of 465 parents of first and fourth grades students in relation to family structure, parent’s education and school achievement. Data were collected through self-report questionnaires during the first year of the study. Analyses show that non traditional families and families of children with learning difficulties are less willing to help with homework. Those families don’t perceive its benefits as much as other families do. Less schooling families and families of children with learning difficulties have low self-efficacy to intervene adequately in homework. Family needs and limits must be taken into consideration by teachers when assigning homework. Key words: homeworks and lessons, family characteristics, parents involvement, pupils of primary education

Characterization of two polyvalent phages infecting Enterobacteriaceae

Bacteriophages display remarkable genetic diversity and host specificity. In this study, we explore phages infecting bacterial strains of the Enterobacteriaceae family because of their ability to infect related but distinct hosts. We isolated and characterized two novel virulent phages, SH6 and SH7, using a strain of Shigella flexneri as host bacterium. Morphological and genomic analyses revealed that phage SH6 belongs to the T1virus genus of the Siphoviridae family. Conversely, phage SH7 was classified in the T4virus genus of the Myoviridae family. Phage SH6 had a short latent period of 16 min and a burst size of 103 ± 16 PFU/infected cell while the phage SH7 latent period was 23 min with a much lower burst size of 26 ± 5 PFU/infected cell. Moreover, phage SH6 was sensitive to acidic conditions (pH < 5) while phage SH7 was stable from pH 3 to 11 for 1 hour. Of the 35 bacterial strains tested, SH6 infected its S. flexneri host strain and 8 strains of E. coli. Phage SH7 lysed additionally strains of E. coli O157:H7, Salmonella Paratyphi, and Shigella dysenteriae. The broader host ranges of these two phages as well as their microbiological properties suggest that they may be useful for controlling bacterial populations

Typologie Des Gîtes Larvaires Et Résistance Des Vecteurs Du Paludisme A La Deltaméthrine Dans les Milieux Urbain Et Rural Du Département De l’Atlantique Au Sud Du Bénin: Données Préliminaires

La lutte antilarvaire récemment recommandée par l’OMS, requiert une connaissance approfondie de la distribution et de la typologie des gîtes larvaires des vecteurs du paludisme. L’objectif de cette étude est d’identifier les différents gîtes larvaires des anophèles et leur mécanisme de résistance à la deltaméthrine. Des prospections larvaires ont été effectuées en 2017 durant les saisons pluvieuses et sèches dans trois communes au sud du Bénin. Les moustiques issus de l’émergence des larves ont été soumis à la deltaméthrine et au bendiocarb selon le protocole de l’OMS. L’identification moléculaire des anophèles et le génotypage de la mutation Kdr ont été réalisés par PCR et l’expression des oxydases, des estérases α et β, et des GST ont été mesurées. Les prospections larvaires ont permis de répertorier 37 gîtes larvaires regroupés en 13 types. La majorité des gîtes étaient anthropiques. La densité larvaire variait d’un type de gîtes à l’autre. An. coluzzii et An. gambiae étaient les deux vecteurs du paludisme vivant en sympatrie dans lestroissites d’étude. Ils sont fortement résistants à la deltaméthrine avec la présence de la mutation kdr à des fréquences très élevées et une augmentation des activités des estérases dans les populations d’anophèles collectés à Zè et des GST à Abomey-Calavi et Allada. La prolifération des vecteurs du paludisme serait imputable à l’insalubrité de l’environnement immédiat et aux activités anthropiques qui créent et assurent le maintien des gîtes larvaires. Ces données pourraient servir au renforcement des stratégies de lutte contre le paludisme déjà en cours. Anopheles larval control, recently recommended by WHO, requires a deep knowledge of the distribution and typology of larval breeding sites. The objective of this study is to identify the different larval habitats colonized by Anopheles and their insecticide resistance mechanism. Larval surveys were carried out in three Districts in south of Benin in 2017, during the rainy and dry seasons. Mosquitoes breeding sites have been characterized and mapped. Mosquitoes from the emergence of larvae were tested to deltamethrin and bendiocarb according to the WHO protocol. The molecular identification of anopheles and the genotyping of the kdr mutation were performed by PCR and the expression of oxidases, esterases, and GSTs was measured. Larval surveys have identified 37 breeding sites categorized into 13 types. Most of the larval habitats were anthropogenics. An. coluzzii and An. gambiae were the two malaria vectors found in sympatric in the three study sites. These two vectors were highly resistant to deltamethrin with the presence of the kdr L1014F mutation at very high frequencies and an increase in esterase activities in anopheline populations collected in Zè and GST in Abomey-Calavi and Allada. The proliferation of malaria vectors is attributable to the unhealthy environment and human activities that create and maintain mosquito breeding. This study highlighted diversity in the type of breeding site of An. gambiae s.s in the Atlantic Department, suggesting the adaptation of this species in its environment. These results could be used to develop an antilarval control strategy in Abomey-Calavi, Zè and in Allada

Widespread anti-CRISPR proteins in virulent bacteriophages inhibit a range of Cas9 proteins

International audienceCRISPR-Cas systems are bacterial anti-viral systems, and bacterial viruses (bacteriophages, phages) can carry anti-CRISPR (Acr) proteins to evade that immunity. Acrs can also fine-tune the activity of CRISPR-based genome-editing tools. While Acrs are prevalent in phages capable of lying dormant in a CRISPR-carrying host, their orthologs have been observed only infrequently in virulent phages. Here we identify AcrIIA6, an Acr encoded in 33% of virulent Streptococcus thermophilus phage genomes. The X-ray structure of AcrIIA6 displays some features unique to this Acr family. We compare the activity of AcrIIA6 to those of other Acrs, including AcrIIA5 (also from S. thermophilus phages), and characterize their effectiveness against a range of CRISPR-Cas systems. Finally, we demonstrate that both Acr families from S. thermophilus phages inhibit Cas9-mediated genome editing of human cells

Characterization of CRISPR-Cas systems in the Ralstonia solanacearum species complex

Clustered regularly interspaced short palindromic repeats (CRISPRs) are composed of an array of short DNA repeat sequences separated by unique spacer sequences that are flanked by associated (Cas) genes. CRISPR‐Cas systems are found in the genomes of several microbes and can act as an adaptive immune mechanism against invading foreign nucleic acids, such as phage genomes. Here, we studied the CRISPR‐Cas systems in plant‐pathogenic bacteria of the Ralstonia solanacearum species complex (RSSC). A CRISPR‐Cas system was found in 31% of RSSC genomes present in public databases. Specifically, CRISPR‐Cas types I‐E and II‐C were found, with I‐E being the most common. The presence of the same CRISPR‐Cas types in distinct Ralstonia phylotypes and species suggests the acquisition of the system by a common ancestor before Ralstonia species segregation. In addition, a Cas1 phylogeny (I‐E type) showed a perfect geographical segregation of phylotypes, supporting an ancient acquisition. Ralstoniasolanacearum strains CFBP2957 and K60T were challenged with a virulent phage, and the CRISPR arrays of bacteriophage‐insensitive mutants (BIMs) were analysed. No new spacer acquisition was detected in the analysed BIMs. The functionality of the CRISPR‐Cas interference step was also tested in R. solanacearum CFBP2957 using a spacer‐protospacer adjacent motif (PAM) delivery system, and no resistance was observed against phage phiAP1. Our results show that the CRISPR‐Cas system in R. solanacearum CFBP2957 is not its primary antiviral strategy

Complete genome sequence of Escherichia coli Siphophage BRET

The lytic Escherichia coli siphophage BRET was isolated from a chicken obtained at a local market in Abidjan, Côte d’Ivoire. Its linear genome sequence consists of 59,550 bp (43.4% GC content) and contains 88 predicted genes, including 4 involved in archaeosine biosynthesis. Phage BRET is related (95% nucleotide identity) to Enterobacteria phage JenK