Automated indoor climate control system

Every year in greenhouse enterprises, more and more attention is paid to the quality maintenance of the microclimate. Correctly chosen technology of microclimate maintenance is one of the most important components that allow increasing yield. And effective use of energy resources is an additional opportunity to significantly reduce the cost of production. The modern automated microclimate control system should support not only the preset mode, but also maximize the use of the capabilities of the executive systems. At the present time, active modernization of greenhouses is being carried out, connected with the increase in the number of executive systems: separation of contours, modernization of ventilation, installation of shading systems, installation of fans. And the more executive systems the greenhouse has, the more important it is for it to choose the criterion that determines the strategy for maintaining the microclimate. For example, one of the most popular management criteria is the saving of heat resources. In this case, it is more appropriate to actively use the lower heating circuits, because They give away heat to the external environment least of all. Another approach to the selection of the criterion involves maintaining the temperature at the growth point higher than at the roots of the plant and thus implies the active use of upper heating circuits. Another criterion of management is based on the fact that the lower contour should maintain a constant temperature in the root zone, the so-called optimum, and only with exhausted resources of other executive systems deviate from it. Experience in the implementation of automated control systems shows that at the design stage of the system it is difficult to select a single management criterion. Therefore, the control system should be able to promptly set the criterion during operation, and the methods of its assignment should visually reflect the agronomic, economic and technical requirements imposed on the system. Thus, the modern management system should allow us to specify not only one of the above control criteria or a combination thereof, but also any other arising in the production process, giving the agronomist technologist ample opportunities in choosing the method for maintaining the temperature and humidity regime in the greenhous

DISCRETE AHLFORS–BEURLING TRANSFORM AND ITS PROPERTIES

The Ahlfors–Beurling transform has been well studied on classical Lebesgue, Morrey, Sobolev, Besov, Campanato, etc. spaces. However, its discrete version is still not studied well. In this paper, we study the properties of the discrete Ahlfors–Beurling transform on discrete Lebesgue spaces

Proteolytic and antimicrobial activities of lactic acid bacteria isolated from traditional Azerbaijani fermented dairy products

Ce travail a été consacré à la recherche des activités protéolytiques et antibactériennes de bactéries lactiques isolées de produits laitiers fermentés traditionnels d Azerbaïdjan. Les souches étudiées ont été isolées de 46 échantillons de produits laitiers fermentés, obtenus dans différentes régions d Azerbaïdjan. Huit souches ayant une activité protéolytique notable ont été purifiées et identifiées par amplification et par séquençage de l ADN 16S comme étant Lactobacillus helveticus (1 souche), Lactobacillus paracasei subsp. paracasei (1 souche), Enterococcus faecalis (6 souches). Deux souches (1 Lactobacillus curvatus et 1 Enterococcus faecium) ayant une activité antibactérienne ont été purifiées et caractérisées. Les activités protéolytiques de ces souches ont été étudiées dans 2 systèmes: croissance dans du lait UHT et système cellulaire non prolifératif. Ces souches hydrolysent toutes les fractions de caséines ce qui démontre leur similarité avec les protéases de type PIII de Lactococcus. Les optima de température et de pH d activité protéolytique sont de 37-45 C et de pH neutre. Les effets de différents inhibiteurs sur les activités protéolytiques indiquent que les souches étudiées produisent des métallo-, sérine- et cystéine-protéases. Ces résultats ont été confirmés par l analyse des souches par PCR gène spécifique avec des amorces de protéases de bactéries lactiques. L'immuno réactivité des caséines b et aS1 mesurée par interaction avec les IgE peut être considérablement réduite par hydrolyse avec Lactobacillus helveticus A75 et Enterococcus faecalis AN1 à la suite de la destruction des épitopes linéaires des IgE. Les souches productrices de bactériocines étudiées dans ce travail inhibent la croissance des souches de bactéries lactiques étroitement liées et aussi des souches pathogènes comme Listeria monocytogenes et Bacillus cereus. La souche Lactobacillus curvatus A61 a également une activité antifongique. Le mode d action de leurs bactériocines dépendant de l organisme test utilisé était bactériostatique ou bactéricide. Enterococcus faecium AQ71 possède les gènes codant pour les enterocines P, L50A/B et A ; la souche Lactobacillus curvatus A61 présente un gène de curvacine. Les substances produites par les souches de LAB azerbaïdjanaises sont stables à la chaleur et actives dans une large gamme de pH. L'analyse des souches par des méthodes de biologie moléculaire a révélé l'absence de gènes de facteurs de virulence. Les souches étudiées ne présentaient pas de multi-résistance aux antibiotiques. Par ailleurs, les souches de LAB azerbaïdjanaises étudiées dans ce travail sont résistantes aux concentrations physiologiques de sels biliaires, ce qui est l une des caractéristiques principales des probiotiques. L ensemble de ces résultats montre que les souches de LAB azerbaïdjanaises sélectionnées, productrices de bactériocines et de protéases, peuvent être utilisées sans risque majeur comme levains ou en co-culture dans les processus de fabrication alimentaire.This thesis was devoted for the study of proteolytic and antimicrobial activities of LAB isolated from traditional Azerbaijani fermented dairy products. LAB isolation was done from 46 samples of traditional fermented dairy products obtained from different regions of Azerbaijan. As a result of the screening 10 new LAB strains were isolated, from which 8 were proteolytic and belong to the species Lactobacillus helveticus (1 strain), Lactobacillus paracasei subsp. aracasei (1 strain) and Enterococcus faecalis (6 strains). Two strains were producers of bacteriocins and belong to species Enterococcus faecium and Lactobacillus curvatus. Specificity of proteolytic activities of studied LAB strains depended on the substrate cleaved and on bacterial growth phase. Found proteolytic activities were mainly directed against caseins. The optimal hydrolysis of substrates by studied strains was observed at 37-45 and at neutral pH range. The studied strains produced several proteases, mainly metallo- and serine- proteases. The proteolysis of caseins by strains Lactobacillus helveticus 75 and Enterococcus faecalis AN1 decreased their immunoreactivity as a result of lytic destruction of IgE binding linear epitopes. The studied bacteriocinogenic strains inhibited the growth of closely related LAB strains and also pathogens such as Listeria monocytogenes, Bacillus cereus. Lactobacillus curvatus A61 also displayed antifungal activity. The mode of action of found bacteriocins was dependent on the test-organism used and was bacteriostatic or bactericidal. Enterococcus faecium AQ71 possesses genes coding enterocins , L50A/B and A. Lactobacillus curvatus A61 possesses the structural gene of curvacin A. Antimicrobial substances produced by the studied LAB strains are heat stable and active in broad pH range. The studied Azerbaijani LAB do not possess the virulence factors and multi-resistance to antibiotics. Thus they are safe for industrial application. Moreover, the studied Azerbaijani LAB strains are resistant to physiological concentrations of bile salts, what is one of the main characteristics of probiotic strains. All these results suggest that the studied bacteriocinogenic and proteolytic strains could be used safely as starter and co-cultures for the food industry.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Proteolytic activities and safety of use of Enterococci strains isolated from traditional Azerbaijani dairy products

International audienceA collection of 147 isolates obtained from 23 samples of traditional Azerbaijani dairy products was screened for the presence of proteolytic enzymes. Six Enterococcus faecalis strains obtained from three cheese samples have been identified as proteinase-producing strains, according to their ability to hydrolyze caseins. RAPD-PCR profiles of their total DNA showed different patterns for strains isolated from different cheese samples. The proteolytic activities of these strains were studied during their growth in milk and in non-proliferative cells system. Isolated strains were able to hydrolyze alpha(S1)-, alpha(S2)-, beta-caseins and BLG albeit to different extents, at optimal pH in the range 6.0-7.2 and optimal temperature in the range 37-45 A degrees C, depending on the strain. Proteolysis was strongly inhibited in the presence of EDTA-specific inhibitor of metalloproteases-but the presence of other types of proteases cannot be excluded. The potential pathogenicity of the strains was evaluated investigating the presence of the genes coding different virulence factors and their resistance to antibiotics. The obtained results yield new information about technological characteristics and safety of studied Enterococci strains from Azerbaijani artisanal dairy products. Many from the isolated strains contribute certainly to the differences in flavor, texture, and taste of Azerbaijani traditional cheeses and could represent new adjunct cultures for the dairy industry

From Peptide Aptamers to Inhibitors of FUR, Bacterial Transcriptional Regulator of Iron Homeostasis and Virulence

International audienceFUR (Ferric Uptake Regulator) protein is a global transcriptional regulator that senses iron status and controls the expression of genes involved in iron homeostasis, virulence, and oxidative stress. Ubiquitous in Gram-negative bacteria and absent in eukaryotes, FUR is an attractive antivirulence target since the inactivation of the fur gene in various pathogens attenuates their virulence. The characterization of 13-aa-long anti-FUR linear peptides derived from the variable part of the anti-FUR peptide aptamers, that were previously shown to decrease pathogenic E. coli strain virulence in a fly infection model, is described herein. Modeling, docking, and experimental approaches in vitro (activity and interaction assays, mutations) and in cells (yeast two-hybrid assays) were combined to characterize the interactions of the peptides with FUR, and to understand their mechanism of inhibition. As a result, reliable structure models of two peptide–FUR complexes are given. Inhibition sites are mapped in the groove between the two FUR subunits where DNA should also bind. Another peptide behaves differently and interferes with the dimerization itself. These results define these novel small peptide inhibitors as lead compounds for inhibition of the FUR transcription factor

Potential use of lactic acid bacteria for reduction of allergenicity and for longer conservation of fermented foods

The interest of consumers for diverse fermented foods has increased in recent years thanks to the positive perception of their impact on consumer health considered as beneficial. Hence, there is an evident need for search of novel ways and for new food preservation agents of natural origins. In this aspect, lactic acid bacteria are very good candidates. It should be highlighted also that the onset of food allergies is rising significantly in recent years. The reduction of the immunoreactivity of food proteins could be achieved thanks to pre-prandial proteolysis occurring in fermented dairy (and other food) systems changing the allergen presentation or cleaving the allergenic protein epitopes, and produce hypoallergenic products.Fil: El-Ghaish, Shady. Institut National de la Recherche Agronomique; FranciaFil: Ahmadova, Aynur. Institut National de la Recherche Agronomique; FranciaFil: Hadji-Sfaxi, Imen. Institut National de la Recherche Agronomique; FranciaFil: El Merchefi, Kamel Eddine. Institut National de la Recherche Agronomique; Francia. Université d’Oran. Département de biologie. Laboratoire de Physiologie de la Nutrition et sécurité Alimentaire; ArgeliaFil: Bazukyan, Inga. Yerevan State University. Faculty of Biology; ArmeniaFil: Choiset, Yvan. Institut National de la Recherche Agronomique; FranciaFil: Rabesona, Hanitra. Institut National de la Recherche Agronomique; FranciaFil: Sitohy, Mahmoud. Institut National de la Recherche Agronomique; Francia. Zagazig University. Faculty of Agriculture. Biochemistry Department; EgiptoFil: Popov, Yuri G.. Yerevan State University. Faculty of Biology; ArmeniaFil: Kuliev, Akif A.. Baku State University. Biotechnical and Biochemistry Chair; AzerbaiyánFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Chobert, Jean-Marc. Institut National de la Recherche Agronomique; FranciaFil: Haertle, Thomas. Institut National de la Recherche Agronomique; Franci