Search

Cet article examine empiriquement la réponse de l'offre agrégée des producteurs de pomme de terre au cours de la période 1966-2018. Nous allons donc (i) vérifier l’existence d’une relation d'équilibre à long terme entre l’offre agricole et les prix des produits agricoles, et (ii) analyser la réactivité de l'offre de ce produit face à des incitations économiques (changement des prix). Pour ce faire, l'analyse de cointégration et le modèle de correction d'erreurs sont utilisés. À long terme, les résultats montrent des élasticités, statistiquement significatives et généralement faibles, entre la surface cultivée et le prix à la production de la pomme terre. Par ailleurs, les élasticités à court terme sont encore plus faibles. Les résultats du modèle de correction d'erreurs ont confirmé une relative réactivité positive aux prix, avec des vitesses d'ajustement lentes surtout dans la dernière décennie. Ce résultat indique que la production de pomme de terre est aussi influencée par d’autres facteurs que le prix. La relative nonpertinence de la réponse d'offre présumée pour la production de pomme de terre, après l’instauration de dispositif Syrpalac, suggère qu’une attention particulière doit être vouée à cette filière afin de contrôler les facteurs qui influent sur la production. English Title: Analysis of aggregate supply response to agricultural prices volatily in Algeria: Case of potato sector This article examines empirically the aggregate supply response of potato growers over the period 1966-2018. We will therefore (i) verify the existence of a long-term equilibrium relationship between agricultural supply and agricultural commodity prices, and (ii) to analyze the responsiveness of the product's supply in the face of economic incentives (price changes). In doing this, cointegration analysis and error correction model will be used. In the long term, the results show statistically significant and generally low elasticities between the agricultural output and the producers’ price of potatoes. Besides, short-term elasticities are even lower. The results of the error correction model confirmed a positive relative reactivity to prices with slow adjustment speeds especially in the last decade. This result indicates that potato production is also influenced by factors other than price. The irrelevance of the presumed supply response for potato production after establishing the Syrpalac dispositive suggests that special attention must be paid to this sector in order to control the factors that influence production. &nbsp

Prokaryotes and eukaryotes have coexisted for millions of years. The hormonal communication between microorganisms and their hosts, dubbed inter-kingdom signaling, is a recent field of research. Eukaryotic signals such as hormones, neurotransmitters or immune system molecules have been shown to modulate bacterial physiology. Among them, catecholamines hormones epinephrine/norepinephrine, released during stress and physical effort, or used therapeutically as inotropes have been described to affect bacterial behaviors (i.e., motility, biofilm formation, virulence) of various Gram-negative bacteria (e.g., Escherichia coli, Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa, Vibrio sp.). More recently, these molecules were also shown to influence the physiology of some Gram-positive bacteria like Enterococcus faecalis. In E. coli and S. enterica, the stress-associated mammalian hormones epinephrine and norepinephrine trigger a signaling cascade by interacting with the QseC histidine sensor kinase protein. No catecholamine sensors have been well described yet in other bacteria. This review aims to provide an up to date report on catecholamine sensors in eukaryotes and prokaryotes, their transport, and known effects on bacteria.

Since antiquity, the ubiquitous lactic acid bacteria (LAB) Enterococci, which are just as predominant in both human and animal intestinal commensal flora, have been used (and still are) as probiotics in food and feed production. Their qualities encounter several hurdles, particularly in terms of the array of virulence determinants, reflecting a notorious reputation that nearly prevents their use as probiotics. Additionally, representatives of the Enterococcus spp. genus showed intrinsic resistance to several antimicrobial agents, and flexibility to acquire resistance determinants encoded on a broad array of conjugative plasmids, transposons, and bacteriophages. The presence of such pathogenic aspects among some species represents a critical barrier compromising their use as probiotics in food. Thus, the genus neither has Generally Recognized as Safe (GRAS) status nor has it been included in the Qualified Presumption of Safety (QPS) list implying drastic legislation towards these microorganisms. To date, the knowledge of the virulence factors and the genetic structure of foodborne enterococcal strains is rather limited. Although enterococcal infections originating from food have never been reported, the consumption of food carrying virulence enterococci seems to be a risky path of transfer, and hence, it renders them poor choices as probiotics. Auspiciously, enterococcal virulence factors seem to be strain specific suggesting that clinical isolates carry much more determinants that food isolates. The latter remain widely susceptible to clinically relevant antibiotics and subsequently, have a lower potential for pathogenicity. In terms of the ideal enterococcal candidate, selected strains deemed for use in foods should not possess any virulence genes and should be susceptible to clinically relevant antibiotics. Overall, implementation of an appropriate risk/benefit analysis, in addition to the case-by-case assessment, the establishment of a strain’s innocuity, and consideration for relevant guidelines, legislation, and regulatory aspects surrounding functional food development seem to be the crucial elements for industries, health-staff and consumers to accept enterococci, like other LAB, as important candidates for useful and beneficial applications in food industry and food biotechnology. The present review aims at shedding light on the world of hurdles and limitations that hampers the Enterococcus spp. genus and its representatives from being used or proposed for use as probiotics. The future of enterococci use as probiotics and legislation in this field are also discussed.

The classification of pathogens in emerging and re-emerging viruses represents major interests in taxonomic studies, functional genomics, host–pathogen interplay, prevention, and disease t...

In the present study, time series for annual, monthly rainfall and number of rainy days per year were analysed to quantify spatial variability and temporal trends for 22 rainfall stations distributed in northeastern Algeria for the period 1978–2010. The Mann–Kendall test and the Sen’s slope estimator were applied to assess the significance and magnitude of the trend. The results showed that precipitation decreases spatially from North to South and from East to West. The application of the Mann–Kendall test (for 0.05% threshold) to the time series data showed that for annual precipitation, no station showed statistically significant trends, unlike the number of rainy days, where there was a significant negative trend in four stations (Jijel, Constantine, Oum El Bouaghi and Tébessa). For the monthly time series, significant positive trends were observed during the months of September in the coastal stations and July for the plateaus and southern Saharan Atlas stations, while significant negative trends were recorded during the months of February and March for the stations of the extreme East in the study area. These results revealed that for the period analysed, there was no significant climate change in northeastern Algeria but there is a seasonal delay having important agroecological implications.

Background Malaria vector control has been implemented chiefly through indoor interventions targeting primary vectors resulting in population declines—pointing to a possible greater proportional contribution to transmission by secondary malaria vectors with their predominant exophagic and exophilic traits. With a historical focus on primary vectors, there is paucity of data on secondary malaria vectors in many countries in Africa. This study sought to determine the species compositions and bionomic traits, including proportions infected with Plasmodium falciparum and phenotypic insecticide resistance, of secondary vectors in three sites with high malaria transmission in Kisumu County, western Kenya. Methods Cross-sectional sampling of adult Anopheles was conducted using indoor and outdoor CDC light traps (CDC-LT) and animal-baited traps (ABTs) in Kakola-Ombaka and Kisian, while larvae were sampled in Ahero. Secondary vectors captured were exposed to permethrin using WHO bioassays and then analyzed by ELISA to test for proportions infected with P. falciparum sporozoites. All Anopheles were identified to species using morphological keys with a subset being molecularly identified using ITS2 and CO1 sequencing for species identification. Results Two morphologically identified secondary vectors captured—An. coustani and An. pharoensis—were determined to consist of four species molecularly. These included An. christyi, An. sp. 15 BSL-2014, an unidentified member of the An. coustani complex (An. cf. coustani) and a species similar to that of An. pharoensis and An. squamosus (An. cf. pharoensis). Standardized (Anopheles per trap per night) capture rates demonstrate higher proportions of secondary vectors across most trapping methods—with overall indoor and outdoor CDC-LTs and ABT captures composed of 52.2% (n = 93), 78.9% (n = 221) and 58.1% (n = 573) secondary vectors respectively. Secondary vectors were primarily caught outdoors. The overall proportion of secondary vectors with P. falciparum sporozoite was 0.63% (n = 5), with the unidentified species An. cf. pharoensis, determined to carry Plasmodium. Overall secondary vectors were susceptible to permethrin with a > 99% mortality rate. Conclusions Given their high densities, endophily equivalent to primary vectors, higher exophily and Plasmodium-positive proportions, secondary vectors may contribute substantially to malaria transmission. Unidentified species demonstrate the need for further morphological and molecular identification studies towards further characterization. Continued monitoring is essential for understanding their temporal contributions to transmission, the possible elevation of some to primary vectors and the development of insecticide resistance. Graphical Abstract

Staphylococcus spp. and Pseudomonas spp. are widely distributed bacteria in the environment and are found in association with animals and humans. Here, we present the draft genome sequence data of the healthy human skin commensal strains Staphylococcus aureus MFP03, Staphylococcus epidermidis MFP04, Staphylococcus capitis MFP08, and Pseudomonas fluorescens MFP05.

This work demonstrates the application of hyaluronan-conjugated nitrogen-doped carbon quantum dots (HA-nCQDs) for bioimaging of tumor cells and illustrates their potential use as carriers in targeted drug delivery. Quantum dots are challenging to deliver with specificity, which hinders their application. To facilitate targeted internalization by cancer cells, hyaluronic acid, a natural ligand of CD44 receptors, was covalently grafted on nCQDs. The HA-nCQD conjugate was synthesized by carbodiimide coupling of the amine moieties on nCQDs and the carboxylic acids on HA chains. Conjugated HA-nCQD retained sufficient fluorescence, although with 30% lower quantum efficiency than the original nCQDs. Confocal microscopy showed enhanced internalization of HA-nCQDs, facilitated by CD44 receptors. To demonstrate the specificity of HA-nCQDs toward human tumor cells, patient-derived breast cancer tissue with high-CD44 expression was implanted in adult mice. The tumors were allowed to grow up to 200–250 mm(3) prior to the injection of HA-nCQDs. With either local or systemic injection, we achieved a high level of tumor specificity judged by a strong signal-to-noise ratio between the tumor and the surrounding tissue in vivo. Overall, the results show that HA-nCQDs can be used for imaging of CD44-specific tumors in preclinical models of human cancer and potentially used as carriers for targeted drug delivery into CD44-rich cells.

The skin constitutes with its microbiota the first line of body defense against exogenous stress including air pollution. Especially in urban or sub-urban areas, it is continuously exposed to many environmental pollutants including gaseous nitrogen dioxide (gNO2). Nowadays, it is well established that air pollution has major effects on the human skin, inducing various diseases often associated with microbial dysbiosis. However, very few is known about the impact of pollutants on skin microbiota. In this study, a new approach was adopted, by considering the alteration of the cutaneous microbiota by air pollutants as an indirect action of the harmful molecules on the skin. The effects of gNO2 on this bacterial skin microbiota was investigated using a device developed to mimic the real-life contact of the gNO2 with bacteria on the surface of the skin. Five strains of human skin commensal bacteria were considered, namely Staphylococcus aureus MFP03, Staphylococcus epidermidis MFP04, Staphylococcus capitis MFP08, Pseudomonas fluorescens MFP05, and Corynebacterium tuberculostearicum CIP102622. Bacteria were exposed to high concentration of gNO2 (10 or 80 ppm) over a short period of 2 h inside the gas exposure device. The physiological, morphological, and molecular responses of the bacteria after the gas exposure were assessed and compared between the different strains and the two gNO2 concentrations. A highly significant deleterious effect of gNO2 was highlighted, particularly for S. capitis MFP08 and C. tuberculostearicum CIP102622, while S. aureus MFP03 seems to be the less sensitive strain. It appeared that the impact of this nitrosative stress differs according to the bacterial species and the gNO2 concentration. Thus the exposition to gNO2 as an air pollutant could contribute to dysbiosis, which would affect skin homeostasis. The response of the microbiota to the nitrosative stress could be involved in some pathologies such as atopic dermatitis.

Pseudomonas aeruginosa PAO1 has an integrated Pf4 prophage in its genome, encoding a relatively well-characterized filamentous phage, which contributes to the bacterial biofilm organization and maturation. Pf4 variants are considered as superinfectives when they can re-infect and kill the prophage-carrying host. Herein, the response of P. aeruginosa H103 to Pf4 variant infection was investigated. This phage variant caused partial lysis of the bacterial population and modulated H103 physiology. We show by confocal laser scanning microscopy that a Pf4 variant-infection altered P. aeruginosa H103 biofilm architecture either in static or dynamic conditions. Interestingly, in the latter condition, numerous cells displayed a filamentous morphology, suggesting a link between this phenotype and flow-related forces. In addition, Pf4 variant-infection resulted in cell envelope stress response, mostly mediated by the AlgU and SigX extracytoplasmic function sigma factors (ECF&sigma, ). AlgU and SigX involvement may account, at least partly, for the enhanced expression level of genes involved in the biosynthesis pathways of two matrix exopolysaccharides (Pel and alginates) and bis-(3&rsquo, 5&rsquo, )-cyclic dimeric guanosine monophosphate (c-di-GMP) metabolism.

International audience

International audience; Le domaine des algorithmes de calcul de plus courts chemins connait un essor important avec le développement du cloud. Quelques solutions, dites multimodales, sont conçues pour combiner divers modes de transports, mais au prix d'une augmentation significative de la complexité. Nous proposons ici MUSE, un algorithme basé sur les séparateurs de graphes, mais adapté au cas multimodal. Dans une phase de prétraitement, nous découpons tout d'abord le graphe en partitions indépendantes (ou cellules), chacune découpée en modes de transport afin de pouvoir plus tard répondreà n'importe quelle requête,. Ensuite, nous précalculons toutes les plus courtes routes, sur ce petit nombre de cellules, en tenant compte des labels (modes) de chaque arête. Nous pouvons ainsi répondreà une requête très rapidement dans la phase online : l'utilisateur spécifie les séquences de mode qu'il autorise, et exploite les plus courtes routes pré-calculées.

In this study, the climatic determinants of cereal yield differentials in the eastern high plateaus of Algeria were explored and analyzed. Using panel data for five regions from the period 2000–2016, we analyzed the relationships between crop yield and two climatic variables (temperature and precipitation) for three major Algerian rainfed cereals: durum wheat, common wheat, and barley. The Mann–Kendall test was applied to assess the significance and magnitude of yield trends, and pooled OLS regression was employed to analyze the determinants of the variability in cereal yields. Results showed that the rainfed cereal yields in this zone are highly variable; that the minimum temperature and average annual precipitation strongly influence cereal yield differentials, with an observed cumulative (lagged) effect; and that the maximum temperature has no direct (or lagged) effect (i.e., its effect on the yield is not statistically significant). The findings of this study also suggest that, despite significant regional differences in semiarid environments, advances in the production technology used in cereal farming have had consistent effects on the yield stability—increasing yields of common wheat but barely influencing yields of durum wheat and barley. These are important findings for the rainfed cereal sector of Algerian dryland agriculture, as they permit a better understanding of the impacts of climate change on Algerian agriculture.

Renewable nanocellulose materials received increased attention owing to their small dimensions, high specific surface area, high mechanical characteristics, biocompatibility, and compostability. Nanocellulose coatings are among many interesting applications of these materials to functionalize different by composition and structure surfaces, including plastics, polymer coatings, and textiles with broader applications from food packaging to smart textiles. Variations in porosity and thickness of nanocellulose coatings are used to adjust a load of functional molecules and particles into the coatings, their permeability, and filtration properties. Mechanical stability of nanocellulose coatings in a wet and dry state are critical characteristics for many applications. In this work, nanofibrillated and nanocrystalline cellulose coatings deposited on the surface of polymer films and textiles made of cellulose, polyester, and nylon are studied using atomic force microscopy, ellipsometry, and T-peel adhesion tests. Methods to improve coatings&rsquo, adhesion and stability using physical and chemical cross-linking with added polymers and polycarboxylic acids are analyzed in this study. The paper reports on the effect of the substrate structure and ability of nanocellulose particles to intercalate into the substrate on the coating adhesion.

We report the draft genome sequences of two Micrococcus luteus strains, MFP06 and MFP07, isolated from human skin. The genome assemblies consist of 2,480 and 2,417 kbp with 2,337 and 2,240 coding sequences, respectively. The genomes contain genes potentially involved in osmotic stress tolerance, DNA repair, monoacylglycerol hydrolysis, and beta-lactone synthesis.

Enterococcus faecalis OB15 is a probiotic strain that was isolated from rigouta, a popular traditional Tunisian fermented cheese. We report here the draft genome sequence of this strain, consisting of 2,912,159 bp, with an average G+C content of 37.49%.

Microbial endocrinology is studying the response of microorganisms to hormones and neurohormones and the microbiota production of hormones-like molecules. Until now, it was mainly applied to the gut and revealed that the intestinal microbiota should be considered as a real organ in constant and bilateral interactions with the whole human body. The skin harbours the second most abundant microbiome and contains an abundance of nerve terminals and capillaries, which in addition to keratinocytes, fibroblasts, melanocytes, dendritic cells and endothelial cells, release a huge diversity of hormones and neurohormones. In the present review, we will examine recent experimental data showing that, in skin, molecules such as substance P, calcitonin gene-related peptide, natriuretic peptides and catecholamines can directly affect the physiology and virulence of common skin-associated bacteria. Conversely, bacteria are able to synthesize and release compounds including histamine, glutamate and γ-aminobutyric acid or peptides showing partial homology with neurohormones such as α-melanocyte-stimulating hormone (αMSH). The more surprising is that some viruses can also encode neurohormones mimicking proteins. Taken together, these elements demonstrate that there is also a cutaneous microbial endocrinology and this emerging concept will certainly have important consequences in dermatology.

Volume 9, no. 1, e01309-19, 2020, [https://doi.org/10.1128/MRA.01309-19][1]. Page 3: Line 3 of Acknowledgments should read as follows. “… and support services) and Catherine Ragimbeau from the Laboratoire National de Sante for providing Illumina raw reads.” [1]: /lookup/doi/10.1128/MRA.

Here, we report the first draft genome sequences of five bacteriocinogenic and potentially probiotic Enterococcus faecium strains (MZF1 to MZF5), which were isolated from homemade Tunisian meat (dried ossban). The estimated median genome sizes were about 2,582,641 ± 109,039 bp, with a median G+C content of 40% ± 0.4%.

Biofilms produced by Pseudomonas aeruginosa present a serious threat to cystic fibrosis patients. Here, we report the draft genome sequences of four cystic fibrosis isolates displaying various mucoid and biofilm phenotypes. The estimated average genome size was about 6,255,986 ± 50,202 bp with a mean G+C content of 66.52 ± 0.06%.