62 research outputs found
Purification et Caractérisation de Biomolécules à partir de microorganismes nouvellement isolés et identifiés
Au cours de ce travail de thĂšse, nous nous sommes intĂ©ressĂ©s aux Ă©tudes taxonomiques des deux souches TN17 et Fr10 qui sont deux nouvelles espĂšces du genre Streptomyces dont nous avons proposĂ© les nomenclatures suivantes : Streptomyces lilaceus sp. TN17 et Streptomyces microflavus sp. Fr10. A partir de la souche Streptomyces lilaceus sp. TN17, trois molĂ©cules on Ă©tĂ© purifiĂ©es et identifiĂ©es par le biais de plusieurs techniques spectroscopiques, il sâagit dâun dĂ©rivĂ© de DKP (L-Leu, L-Arg), un dĂ©rivĂ© de phtalate le di-(2-Ă©thylhexyl) phtalate et un tĂ©rtrapeptide cyclique : le 1 - [2 -(cyclopentanecarbonyl-3-phenylpropionyl] â pyrrolidine-2-carboxylique (1-carbamoyl-propyl)-amide. Ces trois molĂ©cules prĂ©sentent des activitĂ©s antibactĂ©riennes et antifongiques. Suite au criblage des souches de bactĂ©ries lactiques productrices de bactĂ©riocines de la collection de notre laboratoire et leurs caractĂ©risations, nous avons identifiĂ© une nouvelle souche de Lactobacillus nommĂ©e Lactobacillus plantarum sp.TN635 qui produit une bactĂ©riocine « BacTN635 » de 3,8 KDa. Cette derniĂšre a Ă©tĂ© purifiĂ©e Ă homogĂ©nĂ©itĂ©, elle possĂšde un spectre dâaction trĂšs large contre les bactĂ©ries Ă Gram+, Ă Gram- et contre les champignons filamenteux et unicellulaires. BacTN635 a un effet bactĂ©ricide contre Listeria ivanovii BUG 496 et fongistatique contre Candida tropicalis R2 CIP203
Purification et Caractérisation de Biomolécules à partir de microorganismes nouvellement isolés et identifiés
Au cours de ce travail de thĂšse, nous nous sommes intĂ©ressĂ©s aux Ă©tudes taxonomiques des deux souches TN17 et Fr10 qui sont deux nouvelles espĂšces du genre Streptomyces dont nous avons proposĂ© les nomenclatures suivantes : Streptomyces lilaceus sp. TN17 et Streptomyces microflavus sp. Fr10. A partir de la souche Streptomyces lilaceus sp. TN17, trois molĂ©cules on Ă©tĂ© purifiĂ©es et identifiĂ©es par le biais de plusieurs techniques spectroscopiques, il sâagit dâun dĂ©rivĂ© de DKP (L-Leu, L-Arg), un dĂ©rivĂ© de phtalate le di-(2-Ă©thylhexyl) phtalate et un tĂ©rtrapeptide cyclique : le 1 - [2 -(cyclopentanecarbonyl-3-phenylpropionyl] â pyrrolidine-2-carboxylique (1-carbamoyl-propyl)-amide. Ces trois molĂ©cules prĂ©sentent des activitĂ©s antibactĂ©riennes et antifongiques. Suite au criblage des souches de bactĂ©ries lactiques productrices de bactĂ©riocines de la collection de notre laboratoire et leurs caractĂ©risations, nous avons identifiĂ© une nouvelle souche de Lactobacillus nommĂ©e Lactobacillus plantarum sp.TN635 qui produit une bactĂ©riocine « BacTN635 » de 3,8 KDa. Cette derniĂšre a Ă©tĂ© purifiĂ©e Ă homogĂ©nĂ©itĂ©, elle possĂšde un spectre dâaction trĂšs large contre les bactĂ©ries Ă Gram+, Ă Gram- et contre les champignons filamenteux et unicellulaires. BacTN635 a un effet bactĂ©ricide contre Listeria ivanovii BUG 496 et fongistatique contre Candida tropicalis R2 CIP203. ABSTRACT : In This Thesis, we are interested in taxonomic studies of two strains TN17 and Fr10 which are two new species of the genus Streptomyces, and we have proposed the following names: Streptomyces lilaceus sp. TN17 and Streptomyces microflavus sp. Fr10. From Streptomyces lilaceus strain sp. TN17, three molecules have been purified and identified by means of several spectroscopic techniques, it is a derivative of DKP (L-Leu, Larg), a derivative of phthalate di-(2-ethylhexyl) phthalate and cyclic peptide 1 - [2 - (cyclopentanecarbonyl-3-phenylpropionyl] - pyrrolidine-2-carboxylic acid (1-carbamoylpropyl)- amide. All three molecules exhibit antibacterial and antifungal activities. A novel strain of lactic acid bacteria was isolated and characterized from a collection of our laboratory. Itâs identified as a new strain of Lactobacillus, named Lactobacillus plantarum sp.TN635 producing a new bacteriocin "BacTN635" of 3.8 kDa, purified to homogeneity and spectrum with a very broad action against Gram + and Gram-, filamentous and unicellular fungi. BacTN635 has a bactericidal effect against Listeria ivanovii BUG 496 and fungistatic against Candida tropicalis R2 CIP203
Taxonomy and antimicrobial activities of a new Streptomyces sp. TN17 isolated in the soil from an oasis in Tunis
An actinomycete strain referred to as TN17 was screened for its antimicrobial activities. The taxonomic status of this strain was established. The organism was found to have morphological and chemotaxonomic characteristics typical of Streptomycetes. Based on the 16S rRNA nucleotide sequences, Streptomyces sp. TN17 was found to have a relationship with Streptomyces lilaceus, Streptomyces gobitricini and Streptomyces lavendofoliae. Combined analysis of the 16 S rRNA gene sequence (FN687757), phylogenetic analysis, fatty acids profile and physiological tests indicated that there are genotypic and phenotypic differences between TN17 and neighboring Streptomyces speciesâ neighbors. Therefore, TN17 is a novel species: Streptomyces sp. TN17 (=DSM 42020T=CTM50229T). A cultured extract of this strain inhibits the growth of several Gram positive and Gram negative bacteria and fungi
Purification and structure elucidation of three naturally bioactive molecules from the new terrestrial Streptomyces sp. TN17 strain
Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1â3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine âDKPâ derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo 1-[2-(cyclopentanecarbonyl-3-phenyl-propionyl]-pyrrolidine-2-carboxylic acid (1-carbamoyl-propyl)-amide, a cyclic tetrapeptide derivative. The chemical structure of these three active compounds was established on the basis of spectroscopic studies (MS and NMR) and by comparison with data from the literature. According to our biological studies, the pure compounds (1â3) possess antibacterial and antifungal activities
Taxonomy, purification and chemical characterization of four bioactive compounds from new Streptomyces sp. TN256 strain
A new actinomycete strain designated TN256, producing antimicrobial activity against pathogenic bacteria and fungi, was isolated from a Tunisian Saharan soil. Morphological and chemical studies indicated that strain TN256 belonged to the genus Streptomyces. Analysis of the 16S rDNA sequence of strain TN256 showed a similarity level ranging between 99.79 and 97.8% within Streptomyces microflavus DSM 40331T and Streptomyces griseorubiginosus DSM 40469T respectively. The comparison of its physiological characteristics showed significant differences with the nearest species. Combined analysis of the 16 S rRNA gene sequences (FN687758), fatty acids profile, and results of physiological and biochemical tests indicated that there were genotypic and phenotypic differentiations of that isolate from other Streptomyces species neighbours. These date strongly suggest that strain TN256 represents a novel species with the type strain Streptomyces TN256 (=CTM50228T). Experimental validation by DNAâDNA hybridization would be required for conclusive confirmation. Four active products (1â4) were isolated from the culture broth of Streptomyces TN256 using various separation and purification steps and procedures. 1: N-[2-(1H-indol-3-yl)-2 oxo-ethyl] acetamide âalkaloidâ derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; 3: 1-Nonadecene and 4: Cyclo (l-Pro-l-Tyr) a diketopiperazine âDKPâ derivative. The chemical structure of these four active compounds was established on the basis of spectroscopic studies NMR and by comparing with data from the literature. According to our biological studies, we showed in this work that the pure compounds (1â4) possess antibacterial and antifungal activities
Ruta montana L. leaf essential oil and extracts
The aims of this study were to assess the antimicrobial efficacy of the leaf essential oil and the leaf extracts of R. montana against Botrytis cinerea, Fusarium oxysporum, Verticillium dahliae, Aspergillus oryzae and Fusarium solani. The oil (1.000 ”g/disk) and the extracts (1.500 ”g/disk) revealed a remarkable antifungal effect against the tested plant pathogenic fungi with a radial growth inhibition percentage of 40.0â80.0 % and 5.0â58.0 %, respectively along with their respective MIC values ranging from 100 to 1100 ”g/mL and 250 to 3000 ”g/mL. The oil had a strong detrimental effect on spore germination of all the tested plant pathogens along with the concentration as well as time-dependent kinetic inhibition of Fusarium oxysporum. Also, the oil exhibited a potent in vivo antifungal effect against Botrytis cinerea on tomato plants. Experiments carried out in plant revealed that the essential oil was slightly effective in suppression of gall formation induced by Agrobacterium tumefaciens on bitter almond. The results of this study indicate that the oil and extracts of R. montana leaves could become natural alternatives to synthetic fungicides to control certain important plant microbial diseases. The GCâMS analysis determined that 28 compounds, which represented 89.03 % of total oil, were present in the oil containing mainly 1-butene, methylcyclopropane, 2-butene and caryophyllene oxide
Integrative Gene Cloning and Expression System for Streptomyces sp. US 24 and Streptomyces sp. TN 58 Bioactive Molecule Producing Strains
Streptomyces sp. US 24 and Streptomyces sp. TN 58, two strains producing interesting bioactive molecules, were successfully transformed using E. coli ET12567 (pUZ8002), as a conjugal donor, carrying the integrative plasmid pSET152. For the Streptomyces sp. US 24 strain, two copies of this plasmid were tandemly integrated in the chromosome, whereas for Streptomyces sp. TN 58, the integration was in single copy at the attB site. Plasmid pSET152 was inherited every time for all analysed Streptomyces sp. US 24 and Streptomyces sp. TN 58 exconjugants under nonselective conditions. The growth, morphological differentiation, and active molecules production of all studied pSET152 integrated exconjugants were identical to those of wild type strains. Consequently, conjugal transfer using pSET152 integration system is a suitable means of genes transfer and expression for both studied strains. To validate the above gene transfer system, the glucose isomerase gene (xylA) from Streptomyces sp. SK was expressed in strain Streptomyces sp. TN 58. Obtained results indicated that heterologous glucose isomerase could be expressed and folded effectively. Glucose isomerase activity of the constructed TN 58 recombinant strain is of about eighteenfold higher than that of the Streptomyces sp. SK strain. Such results are certainly of importance due to the potential use of improved strains in biotechnological process for the production of high-fructose syrup from starch
Zinc oxide nanoparticles in meat packaging: A systematic review of recent literature
Questions have been raised apropos food spoilage, which may pose a great hazard to the global environment and
human health. Amongst bio-safe material that retains photocatalysis and impacts, photo-oxidizing on biological
and species chemical are ZnO nanoparticles (ZnO-NPs). In this respect, this current paper covers a wide range of
topics, starting from the ZnO-NPs synthesis and antibacterial potential to their functional application in meat
packaging. A deep comparison of the physicochemical properties of ZnO-NPs synthesized through different
routers was reported. In addition, a special focus has been given to antibacterial mechanisms that underlie
synthesis parameters. This review also examined the ZnO-NPs impact on the chemicoâphysicoâmechanical
properties of the functional coatings/films features. Likewise, the employment of ZnO-NPs in meat packaging
was also evaluated. As safer nanoparticles, ZnO-NPs enhance stored meat product quality by microflora growth
limitation and retards lipid/protein oxidation. Remarkably, active packaging comprising ZnO-NPs, synthesized
or not by plants, showed an eco-friendly solution and future alternative in the meat industry. Information about
these topics could help students and scientific researchers who are engaged in chemical engineering, chemistry
and meat technology communities to approach the complex thematic of ZnO-NPs.CYTED | Ref.119RT0568GAIN (Axencia Galega de InnovaciĂłn) | Ref. IN607A2019/01Universidade de Vigo/CISUG
Gen Zâs Willingness to Adopt Plant-Based Diets: Empirical Evidence from Greece, India, and the UK [Preprint]
Comprising the largest population cohort on this planet, Gen Z presents a future-oriented consumer segment driven by climate change and food. This study sought to investigate Gen Zâs perceptions toward plant-based foods and diets and explore the relationship that attitude components, meal preparation involvement, personal and lifestyle factors, and perceived barriers in adopting a plant-based diet have with willingness to adopt green-eating practices. Using cross-sectional data from university students in Greece, India, and the UK, various tools were employed to determine the factors influencing youthsâ consumer behaviour toward animal-protein substitutes. PCA indicated the underlying dimensions of studentsâ viewpoints on plant-based foods, whereas hierarchical and k-means clustering provided the cluster structure. An ordered probit model was estimated to delineate Gen Zâs willingness to adopt plant-based diets and distinguish among mostly unwilling, somewhat willing, and mostly willing youths. Our findings identified two consumer segments, namely proponents and opponents of plant-based foods and diets, with statistically significant differences in the perceived health benefits of plant-based diets, attachment to animal-based proteins, perceived exclusion of animal-based foods, dissatisfaction with plant-based foodsâ attributes, and demand for ensuring adequate protein intake. The ordered probit model estimates showed that there is a «homogeneity» in the factors influencing youthsâ intention to adopt plant-based diets, with attitude components, meal preparation indicators, perceived barriers to eating âgreenâ, and personal factors, such as self-assessed knowledge of healthy eating and physical activity, being strongly associated with studentsâ willingness to switch to plant-based diets in all three countries. Mapping potential obstacles and enablers in terms of shifting to more green-eating behaviours, our findings could add information to better understand the factors affecting food choice and youthsâ transition to a more sustainable lifestyle
Seafood processing, preservation, and analytical techniques in the age of industry 4.0
Fish and other seafood products are essential dietary components that are highly appreciated
and consumed worldwide. However, the high perishability of these products has driven
the development of a wide range of processing, preservation, and analytical techniques. This development
has been accelerated in recent years with the advent of the fourth industrial revolution
(Industry 4.0) technologies, digitally transforming almost every industry, including the food and
seafood industry. The purpose of this review paper is to provide an updated overview of recent
thermal and nonthermal processing and preservation technologies, as well as advanced analytical
techniques used in the seafood industry. A special focus will be given to the role of different Industry
4.0 technologies to achieve smart seafood manufacturing, with high automation and digitalization.
The literature discussed in this work showed that emerging technologies (e.g., ohmic heating, pulsed
electric field, high pressure processing, nanotechnology, advanced mass spectrometry and spectroscopic
techniques, and hyperspectral imaging sensors) are key elements in industrial revolutions not
only in the seafood industry but also in all food industry sectors. More research is still needed to
explore how to harness the Industry 4.0 innovations in order to achieve a green transition toward
more profitable and sustainable food production systems.JosĂ© S. CĂąmara and Rosa Perestrelo acknowledge FCT-Fundação para a CiĂȘncia
e a Tecnologia through the CQM Base FundâUIDB/00674/2020, and Programmatic FundâUIDP/00674/2020, Madeira 14â20 Program, project PROEQUIPRAMâReforço do Investimento em Equipamentos
e Infraestruturas CientĂficas na RAM (M1420-01-0145-FEDER-000008), and ARDITIâAgĂȘncia
Regional para o Desenvolvimento da Investigação Tecnologia e Inovação, through M1420-01-0145-
FEDER-000005âCentro de QuĂmica da MadeiraâCQM+ (Madeira 14â20 Program) for their support.
The research leading to these results was supported by MICINN supporting the RamĂłn y Cajal grant
for M.A. Prieto (RYC-2017-22891); by Xunta de Galicia for supporting the program EXCELENCIAED431F
2020/12; and the pre-doctoral grant of P. Garcia-Oliveira (ED481A-2019/295); and by the
program BENEFICIOS DO CONSUMO DAS ESPECIES TINTORERA-(CO-0019-2021).info:eu-repo/semantics/publishedVersio
- âŠ