Letteratura scientifica selezionata sul tema "Antimicrobial propertie"
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Articoli di riviste sul tema "Antimicrobial propertie":
1
Ademovic, Zahida, Snjezana Hodzic, Zarka Halilic-Zahirovic, Darja Husejnagic, Jasna Dzananovic, Broza Saric-Kundalic e Jasmin Suljagic. "Phenolic compounds, antioxidant and antimicrobial properties of the wild cherry (Prunus avium L.) stem". Acta Periodica Technologica, n. 48 (2017): 1–13. http://dx.doi.org/10.2298/apt1748001a.
Abstract (sommario):
The aim of this study was to determine the total phenolic content, evaluate antioxidant propertie and antimicrobial potential, and identify phenolic compounds in alcoholic and aqueous extracts of the wild cherry (Prunus avium L.) stems collected in Bosnia and Herzegovina. Alcoholic extracts had higher contents of phenolic and flavonoid components, as well as the antioxidant and ferric reducing antioxidant capacity in comparison to aqueous extracts. All extracts were characterized by HPLC analysis. Furthermore, for the first time, the antimicrobial properties of wild cherry stem extracts were evaluated. Quercetin and (+)-catechin were the main compounds identified in the alcoholic extract, followed by chlorogenic acid and rutin. Quercetin was also the major component detected in aqueous extracts. Besides, alcoholic extract showed better antibacterial properties against Staphylococcus aureus as a representative gram-positive bacteria than infusion, whereas none of the samples showed antibacterial activity against Escherichia coli and fungus Candida albicans.
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Benhelima, Abdelkader, Olivier Vidal, Zohra Kaid-Omar, Rabea Sahki e Jean-Marie Lacroix. "Antibacterial, Antibiofilm and Antioxidant Activities of some Medicinal Plants from Pharmacopoeia of Tassili N’ajjer". Journal of Pure and Applied Microbiology 14, n. 3 (24 agosto 2020): 1835–44. http://dx.doi.org/10.22207/jpam.14.3.22.
Abstract (sommario):
Three plants adopted by nomads at Tassili n’ajjer (south Algeria) in traditional medicine namely, Cymbopogon schoenanthus, Anabasis articulata and Salvia chudaei, were analysed for theirs antibacterial, antibiofilm and antioxidant properties. Total flavonoid and phenolic contents were measured with 2% AlCl3 and Folin-Ciocalteu’s reagent method, respectively. The antibacterial propertie was investigated by measurement of MIC of plants extract inhibing bacterial proliferation. The antibiofilm propertie was calculated by fluorescent quantization of the DAPI labeled bacterial biomass fixed on the surface and by COMSTAT analysis of confocal scanning laser microscopy (CSLM) images. DPPH radical scavenging and β-carotene/linoleate bleaching methods were used to determine the antioxidant activities of the plants. Total phenolic content was ranged from 21.98 to 2.51 (gallic acid equivalents mg/g methanolic extracts) and the total flavonoid content ranged from 19.27 to 1.65 (catechin equivalent mg/g methanolic extracts). Antibacterial activity against four Gram positive bacteria was shown with plants extracts. The biofilm inhibition concentration of extracts decreasing 50% of biofilm cell density (BIC50) for Salvia chudaei and Cymbopogon schoenanthus extracts ranges from 1 to 10 µg/mL. CSLM images analysis revealed that both surface covering by germ and three dimensional development of the biofilm were reduced with plants extracts. For antioxidant activities, the methanol extracts of the plants evaluated showed low antioxidant activity, with a IC50 between 1.94 and 6.16 mg/ml. Thus, Our systematic research showed that this three common plants of Sahara desert has diversified phytochemicals possessing satisfying extent of antimicrobial, antibiofilm and antioxidant activities.
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Leitão, Jorge, Silvia Sousa, Silvestre Leite e Maria Carvalho. "Silver Camphor Imine Complexes: Novel Antibacterial Compounds from Old Medicines". Antibiotics 7, n. 3 (26 luglio 2018): 65. http://dx.doi.org/10.3390/antibiotics7030065.
Abstract (sommario):
The emergence of bacterial resistance to available antimicrobials has prompted the search for novel antibacterial compounds to overcome this public health problem. Metal-based complexes have been much less explored than organic compounds as antimicrobials, leading to investigations of the antimicrobial properties of selected complexes in which silver may occupy the frontline due to its use as medicine since ancient times. Like silver, camphor has also long been used for medicinal purposes. However, in both cases, limited information exists concerning the mechanisms of their antimicrobial action. This work reviews the present knowledge of the antimicrobial properties of camphor-derived silver complexes, focusing on recent research on the synthesis and antimicrobial properties of complexes based on silver and camphor imines. Selected examples of the structure and antimicrobial activity relationships of ligands studied so far are presented, showing the potential of silver camphorimine complexes as novel antimicrobials.
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Otero, María Carolina, Juan A. Fuentes, Cristian Atala, Sara Cuadros-Orellana, Camila Fuentes e Felipe Gordillo-Fuenzalida. "Antimicrobial Properties of Chilean Native Plants: Future Aspects in Their Application in the Food Industry". Foods 11, n. 12 (15 giugno 2022): 1763. http://dx.doi.org/10.3390/foods11121763.
Abstract (sommario):
Food contamination with microorganisms is responsible for food spoilage, deterioration and change of organoleptic properties of foods. Besides, the growth of pathogenic microorganisms can provoke serious health problems if food is consumed. Innovative packaging, such as active packaging, is increasing rapidly in the food industry, especially in applying antimicrobials into delivery systems, such as sachets. Chile is a relevant hotspot for biodiversity conservation and a source of unique bio-resources with antimicrobial potential. In this review, fifteen native plants with antimicrobial properties are described. Their antimicrobial effects include an effect against human pathogens. Considering the emergence of antimicrobial resistance, searching for new antimicrobials to design new strategies for food pathogen control is necessary. Chilean flora is a promising source of antimicrobials to be used in active packaging. However, further studies are required to advance from laboratory tests of their antimicrobial effects to their possible effects and uses in active films.
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TUTAR, Uğur, e Cem ÇELİK. "Antibiofilm and Antimicrobial Properties of 1-allyl-3-(2-diisopropylaminoethyl) Benzimidazolium Chloride and its Silver(I)-NHC Complex". Cumhuriyet Science Journal 43, n. 3 (30 settembre 2022): 432–36. http://dx.doi.org/10.17776/csj.1121787.
Abstract (sommario):
Today, the number of antimicrobials used in treatment has decreased, especially due to drug resistance. We need new antimicrobials. Biofilms are an important cause of antimicrobial resistance. In this study, the antimicrobial and antibiofilm properties of the salt and silver complex of benzimidazolium-based NHC compound, which were previously synthesized and characterized, were evaluated. The antimicrobial properties were tested using the broth microdilution method, while their antibiofilm potential was determined by microtiter plate assay. Salt of the NHC compound (1a) showed antimicrobial activity on microorganisms at concentrations between 31.25-125 µg/mL. The silver complex (2a) of the NHC compound showed higher antimicrobial and antibiofilm activity than the salt compound. This activity was highest on Candida albicans yeast (MIC 3.9 µg/mL). Compound 2a reduced the biofilm structure of C. albicans yeast by 86.1% compared to the control. In addition, compound 2a showed 76.4-80.6% antibiofilm activity on gram-negative bacteria. NHC compounds are seen as a promising resource for the development of new generation antimicrobials. The NHC compound evaluated in this study was found to have significant antimicrobial and antibiofilm activity. These compounds could be an important resource for the discovery of future biofilm-acting antimicrobials.
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Šmidrkal, J., T. Karlová, V. Filip, M. Zárubová e I. Hrádková. "Antimicrobial properties of 11-cyclohexylundecanoic acid". Czech Journal of Food Sciences 27, No. 6 (23 dicembre 2009): 463–69. http://dx.doi.org/10.17221/181/2009-cjfs.
Abstract (sommario):
The fact that milk fat contains many minor fatty acids is mostly neglected. It is known that 11-cyclohexylundecanoic acid is contained in cow’s milk fat in the amount of 0.1–0.2%. It is also contained in human milk. 11-Cyclohexylundecanoic acid was synthesised, purified to 99.5% (GC) and its antimicrobial properties were investigated. It was found that 11-cyclohexylundecanoic acid has inhibitory effects on <i>Bacillus cereus</i>, <i>Escherichia coli</i>, and <i>Fusarium culmorum</i> from the concentration of 0.05 mmol/l, however, no antimicrobial effect on Saccharomyces cerevisiae has been determined. 11-Cyclohexylundecanoic acid was found also in goat and cow milk fat on the level of 0.1–0.2%. It is convenient to hydrogenate the sample of fat before the determination of 11-cyclohexylundecanoic acid by GC method. Keywords:
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Pereira da Silva Junior, João Portilho, Janaina Da Costa Nogueira, Waldireny Rocha Gomes e Adriana Dantas Gonzaga de Freitas. "Avaliação In Vitro do Potencial Antimicrobiano de Extratos do Urucum (Bixa orellana L.)". UNICIÊNCIAS 27, n. 2 (13 dicembre 2023): 130–33. http://dx.doi.org/10.17921/1415-5141.2023v27n2p130-133.
Abstract (sommario):
A espécie Bixa orellana L., popularmente conhecida como urucum, é utilizada como corante. Embora estudos descrevam propriedades medicinais da Bixa orellana L., ainda há poucos relatos sobre suas propriedades anti-inflamatórias e antimicrobianas, abrindo assim maiores possibilidades de estudos envolvendo essa planta. A investigação da atividade antimicrobiana, em espécies vegetais, se apresenta como uma alternativa a um problema emergente de saúde pública, a resistência microbiana, que vem aumentando, de forma alarmante, por conta do uso indiscriminado de antibióticos pela população. Esta pesquisa teve como objetivo avaliar o potencial antimicrobiano dos extratos de folhas, cascas e sementes do urucum, a partir de processos de extração de compostos ativos por ultrassom e soxhlet. Os extratos obtidos foram analisados frente a quatro micro-organismos patogênicos Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa e Klebsiella pneumoniae. A avaliação da atividade antimicrobiana ocorreu através do método de difusão em disco em meio Miller Hinton, os discos contendo os extratos vegetais foram depositados sobre as culturas bacterianas previamente inoculadas, o teste foi realizado em triplicata. O principal resultado observado foi o halo de inibição com extratos de folhas para Pseudomonas aeruginosa e Klebsiella pneumoniae, enquanto para os testes com extratos da casca apresentou halo inibitório contra Staphylococcus aureus. Novos testes devem ser realizados para comprovar a atividade antimicrobiana desta espécie. Palavras-chave: Bixa orellana L. Urucum. Potencial Antimicrobiano. Extratos. Abstract The species Bixa orellana L. popularly known as annatto, is used as a natural coloring and food coloring. Although studies describe medicinal properties of Bixa orellana, there are still few reports on its anti-inflammatory and antimicrobial properties, thus opening up greater possibilities for studies involving this plant. The investigation of antimicrobial activity in plant species with medicinal potential is an alternative to an emerging public health problem, microbial resistance, which has been increasing alarmingly due to the indiscriminate use of antibiotics by the population. Research in the area of microbiology is necessary in the search for new active compounds, especially those from natural sources that can act to combat these new strains. This research aimed to evaluate the antimicrobial potential of extracts of annatto leaves, bark and seeds based on active compound extraction processes using ultrasound and soxhlet. The extracts obtained were analyzed against four pathogenic microorganisms Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The evaluation of antimicrobial activity was carried out using the disk diffusion method in Miller Hinton medium, the disks containing the plant extracts were deposited on the previously inoculated bacterial cultures, the test was carried out in triplicate. The main results observed were the inhibition halo with leaf extracts for Pseudomonas aeruginosa and Klebsiella pneumoniae, while tests with bark extracts showed an inhibitory halo against Staphylococcus aureus. New tests must be developed to prove the antimicrobial activity of this species. Keywords: Bixa orellana L. Annatto. Antimicrobial Potential. Extracts.
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MacDermott-Opeskin, Hugo I., Vrinda Gupta e Megan L. O’Mara. "Lipid-mediated antimicrobial resistance: a phantom menace or a new hope?" Biophysical Reviews 14, n. 1 (febbraio 2022): 145–62. http://dx.doi.org/10.1007/s12551-021-00912-8.
Abstract (sommario):
Abstract The proposition of a post-antimicrobial era is all the more realistic with the continued rise of antimicrobial resistance. The development of new antimicrobials is failing to counter the ever-increasing rates of bacterial antimicrobial resistance. This necessitates novel antimicrobials and drug targets. The bacterial cell membrane is an essential and highly conserved cellular component in bacteria and acts as the primary barrier for entry of antimicrobials into the cell. Although previously under-exploited as an antimicrobial target, the bacterial cell membrane is attractive for the development of novel antimicrobials due to its importance in pathogen viability. Bacterial cell membranes are diverse assemblies of macromolecules built around a central lipid bilayer core. This lipid bilayer governs the overall membrane biophysical properties and function of its membrane-embedded proteins. This mini-review will outline the mechanisms by which the bacterial membrane causes and controls resistance, with a focus on alterations in the membrane lipid composition, chemical modification of constituent lipids, and the efflux of antimicrobials by membrane-embedded efflux systems. Thorough insight into the interplay between membrane-active antimicrobials and lipid-mediated resistance is needed to enable the rational development of new antimicrobials. In particular, the union of computational approaches and experimental techniques for the development of innovative and efficacious membrane-active antimicrobials is explored.
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Permatananda, Pande Ayu Naya Kasih, I Gde Suranaya Pandit, Putu Nita Cahyawati e Anak Agung Sri Agung Aryastuti. "Antimicrobial Properties of Eco Enzyme: A Literature Review". Bioscientia Medicina : Journal of Biomedicine and Translational Research 7, n. 6 (21 luglio 2023): 3370–76. http://dx.doi.org/10.37275/bsm.v7i6.831.
Abstract (sommario):
Background: In surgical medicine, the use of antimicrobials is very important. The use of antimicrobials or antibiotics is used at the time before surgery as prophylaxis, intraoperative, and postoperative. The prevention of some bacterial infections is imperative. The latest research is constantly evolving toward the use of antibiotics, which follows an increasingly resistant antibiotic trend. One of the advancements in the use of antimicrobials is eco enzymes.
Methods: The literatures reviewed in our study was gathered from PubMed and Google Scholar. The advanced search was conducted on PubMed with the keywords used ("Eco enzyme" AND "antimicrobial" AND "activity" OR "Antibiotics"; "Mechanism" OR "Nature"). The advanced search was also conducted on Google Scholar with all of the words "antimicrobial activity of eco enzyme". We reviewed the articles cited within the literature to broaden the search results.
Results: Some materials used as eco enzymes in this literature review include Carica papaya L., Annona muricata L., Azadirachta indica Cymbopogon winterianus, Ananas comosus, citrus aurantium, etc. Bioactive substances that play a role in microbacterial activity are flavonoids, tannins, saponins, pH, and lactic acids through mechanisms inhibiting nucleic acid synthesis, inhibit cell membrane function, inhibiting energy metabolism of bacteria, and cross-bacterial cell membranes because of the pH gradient, leading to the disruption of cellular metabolic activities of bacterias.
Conclusion: Eco enzymes have been shown to have antimicrobial abilities.
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Svizhak, V. K., S. E. Dejneka, V. A. Chornous, O. I. Azarov e V. J. Svizhak. "Antimicrobial Properties of New Derivatives of Imidazole". Mikrobiolohichnyi Zhurnal 79, n. 5 (30 settembre 2017): 46–56. http://dx.doi.org/10.15407/microbiolj79.05.046.
Tesi sul tema "Antimicrobial propertie":
1
Prats, Ejarque Guillem. "Exploring the pharmacological properties of human antimicrobial ribonucleases". Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671628.
Abstract (sommario):
Aquesta tesi s’enfoca en la caracterització estructural i funcional de les propietats biològiques de les RNases antimicrobianes de la superfamília de la RNasa A. Concretament, s’han assolit els següents objectius a curt termini:
La caracterització estructural i funcional de la RNasa 6 per cristal·lografia de raigs X, dinàmica molecular, mutagènesi dirigida i anàlisis enzimàtics destaca el paper clau de les regions remotes d’unió al substrat. A part, hem identificat un possible segon centre actiu en la RNasa 6. Finalment, un estudi evolutiu dels diversos membres de la superfamília de la RNasa A ha revelat una tendència clara, al llarg de l’evolució en vertebrats, des de la preferència de guanina cap a la d’adenina en l’arquitectura de la regió secundària d’unió a bases B2.
Al llarg del treball experimental realitzat en aquesta tesi, hem buscat la caracterització del mecanisme d’acció bactericida de les RNases, una de les principals línies de recerca del nostre grup de recerca. En aquest treball, ens hem enfocat específicament en l’optimització del pèptid antimicrobià derivat de l‘N-terminal de la RNasa 3, ECP(5-17P24-36), i en el disseny d’una RNasa quimèrica antimicrobiana (RNasa 3/1).
Respecte el pèptid ECP(5-17P24-36), s’ha optimitzat mitjançant diverses metodologies, arribant a la conclusió que el millor candidat antimicrobià és el seu enantiòmer total D-ECP(5–17P24–36). Pel que fa a la RNasa 3/1, aquesta incorpora les característiques estructurals de les RNases 1 i 3, combinant així la seva elevada activitat catalítica i bactericida, respectivament. Es va dissenyar un primer constructe amb èxit, malgrat que no presentava els mateixos nivells d’activitat bactericida que la RNasa 3. Aleshores, vam dissenyar dues versions noves de la RNasa 3/1 que incorporaven el loop C-terminal de la RNasa 3, en el qual es va identificar un motiu estructural específic associat al reclutament de l’autofagosoma. És interessant destacar la capacitat de la primera versió de la quimera RNasa 3/1 d’endarrerir l’adquisició de resistència a la colistina en un assaig evolutiu in vitro d’exposició a la colistina en cultius d’Acinetobacter baumannii.
En global, aquests resultats ajudaran a elucidar el mode d’unió a l’RNA de les ribonucleases i el seu mecanisme antimicrobià, així com la seva contribució en el sistema immunitari innat, amb prometedores aplicacions farmacològiques.Esta tesis se enfoca en la caracterización estructural y funcional de las propiedades biológicas de las RNasas antimicrobianas de la superfamilia de la RNasa A. Concretamente, se han alcanzado los siguientes objetivos en el corto plazo: La caracterización estructural y funcional de la RNasa 6 por cristalografía de rayos X, dinámica molecular, mutagénesis dirigida y análisis enzimáticos destaca el papel clave de las regiones remotas de unión al sustrato. A parte, hemos identificado un posible segundo centro activo en la RNasa 6. Finalmente, un estudio evolutivo de los distintos miembros de la superfamilia de la RNasa A ha revelado una tendencia clara, a lo largo de la evolución en vertebrados, desde la preferencia de la guanina hacia adenina en la arquitectura de la región secundaria de unión a bases B2. A lo largo del trabajo experimental realizado en esta tesis, hemos buscado la caracterización del mecanismo de acción bactericida de las RNasas, una de las principales líneas de investigación de nuestro grupo de investigación. En este trabajo, nos hemos enfocado específicamente en la optimización del péptido derivado del N-terminal de la RNasa 3, ECP(5-17P24-36), y en el diseño de una RNasa quimérica antimicrobiana (RNasa 3/1). Respecto al péptido ECP(5-17P24-36), se ha optimizado mediante varias metodologías, llegando a la conclusión que el mejor candidato antimicrobiano es su enantiómero total D-ECP(5-17P24-36). Por lo que respecta a la RNasa 3/1, esta incorpora las características estructurales de las RNasas 1 y 3, combinando así su elevada actividad catalítica y bactericida, respectivamente. Se diseñó un primer constructo con éxito, pese a que no presentaba los mismos niveles de actividad bactericida que la RNasa 3. Entonces, diseñamos dos nuevas versiones de la RNasa 3/1 que incorporaban el loop C-terminal de la RNasa 3, en el que se identificó un motivo estructural específico asociado al reclutamiento del autofagosoma. Es interesante destacar la capacidad de la primera versión de la quimera RNasa 3/1 de retrasar la adquisición de resistencia a la colistina en un ensayo evolutivo in vitro de exposición a la colistina en cultivos de Acinetobacter baumannii. En global, estos resultados ayudarán a elucidar el modo de unión al RNA de las ribonucleasas y su mecanismo antimicrobiano, así como su contribución en el sistema inmunitario innato, con prometedoras aplicaciones farmacológicas.
This thesis project focuses on the structural-functional characterization of the biological properties of antimicrobial RNases from the RNase A superfamily. Specifically, the following short-term goals have been achieved: Structural and functional characterization of RNase 6 by X-ray crystallography, molecular dynamics, site-directed mutagenesis and enzymatic analysis have highlighted the key role of remote binding subsites. Besides, we have identified in RNase 6 a putative novel secondary active site. In addition, an evolutionary study of several members of the RNase A superfamily have revealed a clear drift from guanine to adenine preference at the secondary base binding site (B2) architecture along vertebrate evolution. During this thesis’ experimental work, we have pursued the characterization of RNases’ bactericidal mechanism of action, a long-term object of study in our research group. Here, we have specifically focused on the optimisation of the antimicrobial peptide derived from RNase 3, ECP(5-17P24-36), and the design of a chimeric antimicrobial RNase (RNase 3/1). Regarding the N-terminus peptide ECP(5-17P24-36), it has been optimised by several methodologies. We have concluded the best antimicrobial candidate to be its total enantiomer, D-ECP(5-17P24-36). As for RNase 3/1, this chimera encompasses structural features from RNases 1 and 3 parental proteins to combine both high catalytic and bactericidal activities. A first construct was successfully achieved, albeit not reaching the bactericidal activity levels of RNase 3. Therefore, we designed two more versions of RNase 3/1 that incorporate the RNase 3 C-terminus loop. A specific tag motif was identified in that region associated to autophagosome recruitment. Interestingly, the hybrid chimera RNase 3/1 was able to delay the acquisition of bacterial resistance to colistin using an in vitro evolutionary exposure assay in Acinetobacter baumannii cultures. Overall, the results shed light on the elucidation of substrate binding architecture and antimicrobial mechanism of action of RNases and their contribution to the innate immune system, with promising pharmacological applications.
Universitat Autònoma de Barcelona. Programa de Doctorat en Bioquímica, Biologia Molecular i Biomedicina
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Cai, Zhiwei. "Nouveaux matériaux à base de polyoxotitanates (POTs) dopé ou à base de complexe salicylate de titane (IV) et d'argent (I)". Electronic Thesis or Diss., Strasbourg, 2023. http://www.theses.fr/2023STRAF062.
Abstract (sommario):
Ces dernières années, le dioxyde de titane a attiré beaucoup d'attention en tant que matériau hautement stable avec une large gamme d'applications allant du pigment blanc à des applications en tant que semi-conducteur ou dispositifs photoniques de pointe. En utilisant des approches synthétiques récemment développées, la synthèse de molécules cages de type polyoxotitanate (POT, [TixOy(OR)z]) atomiquement bien définies peut être menée. Les POTs peuvent être considérés comme des modèles solubles du TiO2. Des cages dopées avec un métal M (M-POT) présentant de nouvelles propriétés peuvent être aussi préparées.Deux nouvelles cages dopées au cérium ont été synthétisées par une réaction solvothermique. Les cages [Ti28O38(OEt)38CeCl](EtOH)1,4 et [Ti8O7(OEt)21Ce](EtOH) ayant des solubilités différentes, elles vont pouvoir être séparées et caractérisées par RMN du 1H et diffraction des rayons X. Des cages POTs dopées au Fe : [Ti4(OEt)15O(FeCl)] et [FeTi14(OEt)28O14(OH)2] ont été également synthétisés.Puis après hydrolyse avec ou sans calcination, les matériaux à base de Ce ou Fe et TiO2 peuvent être obtenus. Des émulsions de ses matériaux et avec le polymère PVDC dopées au cérium ou au fer ont ensuite été déposées sur une surface de PVC. Les performances d'absorption UV et de barrière à l'eau augmentent progressivement avec l'augmentation de la quantité de matériaux déposés. Les résultats sont intéressants pour l’emploi de ces matériaux en surface d’’emballage de tablettes de médicaments, ce qui permettra d’augmenter la date de péremption de ceux-ci.La cage Eu-POT dopée avec l’Eu (III) : Ti2O(OEt)8EuIIICl(EtOH)]2 a été synthétisé, puis après hydrolyse et calcination, les propriétés de photoluminescence du matériau obtenu ont été étudiées.Enfin, un complexe AgITiIV(SC)2(HSC)(CH3CN) (SC2- = l'acide salicylique) a été préparé. Après hydrolyse et calcination, les propriétés antimicrobiennes des matériaux fabriqués ont été testé vis-à-vis avec succès du S. aureus ou de E. ColisIn recent years, titanium dioxide has attracted much attention as a highly stable material with a wide range of applications from white pigment to its applications as a semiconductor or advanced photonic devices. Using recently developed synthetic approaches, the synthesis of atomically well-defined polyoxotitanate (POT, [TixOy(OR)z]) cage molecules can be determined. POTs may be preferred as soluble models of TiO2. Cages doped with a metal M (M-POT) presenting new properties can also be prepared.Two new cages doped with cerium were synthesized by a solvothermal reaction. The cages [Ti28O38(OEt)38CeCl](EtOH)1.4 and [Ti8O7(OEt)21Ce](EtOH) having different solubilities, they will be able to be separated and characterized by 1H NMR and X-ray diffraction. The Fe-doped POTs: [Ti4(OEt)15O(FeCl)] and [FeTi14(OEt)28O14(OH)2] were also synthesized. Then after hydrolysis with or without calcination, materials based on Ce or Fe and TiO2 can be obtained. Emulsions of its materials and with the cerium-doped PVDC polymer were then deposited on a PVC surface. UV absorption and water barrier performance gradually increases with increasing amount of deposited materials. The results are interesting for the use of these materials on the packaging surface of drug tablets, which will increase their expiry date. The Eu-POT cage doped with the Eu(III): Ti2O(OEt)8EuIIICl(EtOH)]2 was also synthesized, then after hydrolysis and calcination, the photoluminescence properties of the obtained material were studied.Finally, an AgITiIV(SC)2(HSC)(CH3CN) complex (SC2- = salicylate) was prepared. After hydrolysis and calcination, the anti-microbial properties of the materials were successfully tested against S. aureus or E. Colis
3
Cinar, Dursun. "Purification and antimicrobial properties of oleuropein". Thesis, University of West London, 2009. https://repository.uwl.ac.uk/id/eprint/381/.
Abstract (sommario):
Olive leaves contain substantial amounts of phenolic substances, including the polyphenol oleuropein. This compound has been reported to possess antimicrobial properties. The purpose of this study was to develop an improved method for the extraction and purification of oleuropein from olive leaves and characterise its activity as well as the mode of action against a range of bacteria. Phenolic compounds from olive leaves were extracted in methanol and oleuropein was separated from the mixture by countercurrent chromatography (CCC). Separation was confirmed by high performance liquid chromatography. CCC processing resulted in a purity of oleuropein of 60% and this was later improved to 90% (compared to 83% in a commercially available oleuropein product). Flash chromatography was successfully introduced as an additional purification step and this eliminated some of the surfactants in the extract. Fifteen strains of bacteria and one yeast, including species commonly associated with hospital infections, were tested for their sensitivity to oleuropein in agar supplemented with oleuropein and by disc diffusion on agar media. Most of the bacteria used in this study were inhibited by oleuropein but the amount of oleuropein required for inhibition varied from 0.25 to 3.0%. The two most sensitive strains were Enterobacter faecalis and one strain of group A Streptococci in agar supplemented with oleuropein. Staphylococcus spp. were inhibited by oleuropein concentrations of 0.5 to 1.5%. Gram-negative species, such as Escherichia coli and Pseudomonas aeruginosa, the Gram-positive Micrococcus Iuteus and Bacillus subtilis as well as the fungus Candida albicans were not inhibited in the same assay. In the disc diffusion test, 10% oleuropein inhibited Gram-negatives (4-15 mm) whereas 5 and 10% oleuropein resulted in inhibition zones from 12 to 30 mm in Gram-positives and C. albicans. Four strains of S. aureus were subjected to further studies. In bacterial-time kill assays, exposure to 2% oleuropein resulted in reductions of up to 6 log cfu mL-1 in 4 hours and 6 hours for two methicillin resistant and two methicillin susceptible strains, respectively. A methicillin susceptible and a methicillin resistant S. aureus were investigated using transmission electron microscopy following exposure to 2% oleuropein. Cells of both types showed leakage of cell contents and ultimately lysis within two and four hours of exposure. Further work on leakage of cell constituents based on absorbance measurements was inconclusive due to interference by coloured compounds formed by the oxidation of oleuropein. Leakage of amino acids from cells treated with oleuropein was investigated using ninhydrin and Bradford assays. It was observed that 12 to 38% of amino acids leaked from S. aureus treated with oleuropein. The results were confirmed by sodium dodecyl acrylamide electrophoresis where several bands were absent from treated cell extracts. In addition, fluorescent microscopy of lectin labelled S. aureus cells was attempted to investigate damage of glycoproteins attached on the extracellular cell wall. Lectin binding was unsuccessful and was replaced by fluorescein isocyanate, which selectively binds to lysine groups; the latter indicated reduced fluorescence in treated cells. In conclusion this work demonstrated the application of a novel purification method based on countercurrent chromatography to obtain oleuropein with improved purity. The antimicrobial studies showed that oleuropein has the potential to eliminate bacteria. The mode of action studies showed that denaturation of proteins by oleuropein occurred, resulting in irreversible cell degradation. Oleuropein might be contemplated as a cleaning agent in envirnoments where strong acids and bases are harmful for equipment.
4
Nilebäck, Linnea. "Recombinant spider silk with antimicrobial properties". Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102804.
Abstract (sommario):
Immobilizing antimicrobial substances onto biocompatible materials is an important approach for the design of novel, functionalized medical devices. By choosing antimicrobial substances from innate immune systems, the risk for development of resistance in pathogenic microbes is lower than if conventional antibiotics are used. Combining natural antimicrobial peptides and bactericidal enzymes with strong and elastic spider silk through recombinant protein technology would enable large-scale production of materials that could serve as functionalized wound dressings. Herein, fusion proteins with the engineered spider silk sequence 4RepCT and five different antimicrobial substances were constructed using two different strategies. In the first, the fusion proteins had a His-tag as well as a solubility-enhancing domain N-terminally to the antimicrobial agent during expression. The tags were cleaved and separated from the target protein during the purification process. The other approach provided a His-tag but no additional solubility domain. The antimicrobial agents included in the work were a charge engineered enzyme and four antimicrobial peptides herein called Peptide A, Peptide B, Peptide C and Peptide D. Four out of five fusion proteins could be expressed in Escherichia coli without exhibiting noticeable toxicity to the host. However, most target proteins were found in the non-soluble fraction. For D-4RepCT, neither soluble nor non-soluble proteins were identified. An operating strategy for expression and purification of antimicrobial spider silk proteins was developed, where the construct system providing the solubility-enhancing domain N-terminally to the antimicrobial sequence, and long time expression at low temperatures is a promising approach. The fusion proteins A-4RepCT and C-4RepCT could be produced in adequate amounts, and they proved to possess the ability to assemble into stable fibers. When incubating solutions of Escherichia coli on the functionalized silk material A-4RepCT, it showed to decrease the number of living bacteria in solution, in contrary to wild-type 4RepCT on which bacteria continued to proliferate. Initial studies of the viability of bacteria adhered to the surface of the functionalized spider silk are so far inconclusive. A larger sample size, complementary experiments and methodology optimization is needed for a proper assessment of antibacterial properties. However, preliminary results for the development of antimicrobial spider silk are positive, and the approach elaborated in this work is believed to be applicable for the construction of functional spider silk with a wide range of natural antimicrobial agents for future wound healing applications.
5
Bortolin, M. "ANTIMICROBIAL PROPERTIES OF PLATELET-RICH PLASMA". Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/233150.
Abstract (sommario):
Autologous platelet concentrates have been widely used in various medical fields in order to promote tissue regeneration. The significance behind their use lies in the presence of growth factors in platelets α-granules that enhance wound healing by promoting cell chemotaxis, proliferation and differentiation. In addition, anti-inflammatory and antibacterial properties of platelet concentrates have been recently pointed out.
In this study, the antimicrobial effect of pure platelet-rich plasma (P-PRP) was evaluated against microorganisms isolated from oral cavity, such as Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus agalactiae and Streptococcus oralis.
Blood samples were obtained from healthy donors. The antibacterial activity of P-PRP, was evaluated as the minimum inhibitory concentration (MIC), determined through the microdilution two-fold serial method, and the minimum microbicidal concentration (MMC), determined by subculturing microbial samples from MIC tests to solid media.
MIC results showed that P-PRP was able to inhibit the growth of E. faecalis, C. albicans, S. agalactiae and S. oralis, but not of P. aeruginosa strains. Moreover, MMB tests showed that C. albicans was less suceptible to P-PRP than other microorganisms.
In conclusion, this study shows that, in adjunct to its well established regenerative properties, P-PRP possess an antimicrobial activity and so might represent a valuable product in the fight against infections
6
Khadambi, Tshiwela Norah. "Antimicrobial properties of phenolic compounds from sorghum". Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-03022007-164705.
7
Parr, J. A. "Antimicrobial properties of silicone quaternary ammonium compounds". Thesis, Bucks New University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375600.
8
Liu, Harris K. (Harris Ken-Ming). "New immobilized antimicrobial polyethylenimines : synthesis and properties". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93039.
Abstract (sommario):
Thesis: S.M., Massachusetts Institute of Technology, Department of Chemistry, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references.
Surfaces modified with immobilized N-alkyl-polyethylenimines (N-alkyl-PEls) containing various alkyl groups were synthesized and tested against various pathogenic human influenza viruses to establish structure-to-virucidal activity relationships. Various physical-chemical properties of each surface were correlated with their virucidal activities to identify key antiviral surface properties. The accessibility of N-alkyl-PEI quaternary ammonium groups to influenza virus was subsequently identified as the key determinant of antiviral efficacy, as demonstrated by FITC-lysozyme surface titration. Previously used multistep syntheses to create antimicrobial surfaces by immobilizing Nalkyl- PEls were replaced with a novel aerosol-assisted plasma deposition procedure. N,N-hexyl,methyl-polyethylenimines were directly plasma-coated onto a glass surface. The resulting material was thoroughly characterized and demonstrated to be robust, scalable, bactericidal against Escherichia cofi, and virucidal against human influenza virus. Biocompatibility and bactericidal properties of N-alkyl-PEls immobilized on Boston Keratoprosthetic implants were evaluated in vivo. Surface-attached N,N-hexyl,methylpolyethylenimines exhibited inhibitory effects on Staphylococcus aureus biofilm formation, with no toxicity or adverse reactivity detected.
by Harris K. Liu.
S.M.
9
Sharma, Shagun. "Investigation of Antimicrobial Properties of Spider Silk". University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1418647204.
10
Desai, Prerak T. "Antimicrobial Properties of Syringopeptin 25A and Rhamnolipids". DigitalCommons@USU, 2006. https://digitalcommons.usu.edu/etd/5526.
Abstract (sommario):
The increasing bacterial resistance to available antibiotics requires the search for new antibacterial compounds to be broadened. This study investigated the antimicrobial properties of two secondary metabolites from fluorescent pseudo monads -- syringopeptin 25A, a lipodepsipeptide produced by Pseudomonas syringae pv. syringae, and a rhamnolipid mixture produced by Pseudomonas aeruginosa. The rate of antimicrobial action was determined by monitoring the rate of uptake of propidium iodide during exposure to the compounds. Inhibition was also confirmed by the microbroth dilution method to determine the MI Cs. Both the compounds inhibited growth of Gram-positive organisms, including Mycobacterium smegmatis, staphylococci, and listeria. Inhibition of spore germination was also notable. SP 25A inhibited two multiple antibiotic strains of Staphylococcus aureus subsp. aureus and Enterococcus faecalis, while RLs failed to do so, even at 60 μg/ml. Addition of the compounds together showed a synergistic activity against Listeria monocytogenes. Neither compound was toxic to human cells in vitro at 8 μg/ml.
It is postulated that both compounds exert their antimicrobial effect by forming pores in the bacterial cell membrane, but we did not observe a relation between membrane permeabilization and inhibition of growth in each case. At sub-MIC concentrations RLs did cause pores in the membrane of L. monocytogenes, while SP 25A did not. However, RLs did not inhibit cell growth, while SP 25A completely inhibited cell growth.
To investigate these effects gene expression was monitored just before treating the cells with the antimicrobials, 30 min after treatment and 120 min after treatment. The gene expression profile was distinct when cells were treated with both the antimicrobials. SP 25A repressed genes related to cell division, intermediary metabolism, transcription, translation, and virulence genes. These effects were not produced when cells were treated with RLs, hence giving indications that even though both the antimicrobials may act on the same site (i.e. the cell membrane), the cellular response was different, which led to different phenotypes for growth.
This work indicates that SP 25A holds promise for further development as a therapeutic agent and provides evidence that the proposed pore-forming model alone does not suffice to explain the mode of action of SP 25A.
Libri sul tema "Antimicrobial propertie":
1
Valgimigli, Luca. Essential oils as natural food additives: Composition, applications, antioxidant and antimicrobial properties. Hauppauge, N.Y: Nova Science Publishers, 2012.
2
J, Cousins D., e C. A. B. International, a cura di. Plants with antimicrobial properties: A bibliography compiled from the CAB abstracts database. Wallingford, Oxon, UK: CAB International, 1995.
3
Marwan, Aref Gheit. The antimicrobial properties of cranberries. 1985.
4
Hili, Pauline. The Antimicrobial Properties of Essential Oils. Winter Press, 2001.
5
Sharma, Ramesh Kumar, Maria Micali, Alessandra Pellerito, Bhupendra Kumar Rana e Rajeev K. Singla. Indian Herbal Medicines: Antioxidant and Antimicrobial Properties. Springer International Publishing AG, 2021.
6
Plants With Antimicrobial Properties: An Annotated Bibliography. C a B Intl, 1995.
7
Antimicrobial Peptides: Properties, Functions and Role in Immune Response. Nova Biomedical, 2013.
8
Photocalytic Coatings for Air-Purifying, Self-Cleaning and Antimicrobial Properties. MDPI, 2015. http://dx.doi.org/10.3390/books978-3-03842-137-5.
9
Chladek, Grzegorz, a cura di. Composite and Polymeric Materials for Dentistry: Enhancing Antimicrobial and Mechanical Properties. MDPI, 2023. http://dx.doi.org/10.3390/books978-3-0365-7182-9.
10
Al-Ahmed, Amir, a cura di. Advanced Applications of Micro and Nano Clay. Materials Research Forum LLC, 2022. http://dx.doi.org/10.21741/9781644901915.
Abstract (sommario):
Due to their characteristic properties, biodegradable nature and non-toxicity, clay-biopolymer based composites have many applications in such advanced fields as drug release, antimicrobial activities, wound healing, tissue engineering, wastewater treatment, food packaging and flame retardant materials. The book reviews fabrication, properties and applications of a great variety of these materials.
Capitoli di libri sul tema "Antimicrobial propertie":
1
Ahmadi, Sepideh, e Navid Rabiee. "Antimicrobial Properties". In ACS Symposium Series, 81–94. Washington, DC: American Chemical Society, 2023. http://dx.doi.org/10.1021/bk-2023-1438.ch006.
2
Malmsten, Martin. "Nanomaterials as Antimicrobial Agents". In Handbook of Nanomaterials Properties, 1053–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-31107-9_25.
3
Ikeda, Junji, Takayuki Murakami, Taito Nakamura e Iwao Noda. "Antimicrobial Properties of Ag-HAp Coating". In Antimicrobial Combination Devices, 138–46. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2020. http://dx.doi.org/10.1520/stp163020200017.
4
Pistelli, Luisa, e Irene Giorgi. "Antimicrobial Properties of Flavonoids". In Dietary Phytochemicals and Microbes, 33–91. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-3926-0_2.
5
Perreault, Francois. "Antimicrobial Properties of Membranes". In Encyclopedia of Membranes, 89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_2009.
6
Perreault, Francois. "Antimicrobial Properties of Membranes". In Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-40872-4_2009-1.
7
Jayakumar, Aswathy, Sabarish Radoor, Jasila Karayil, Indu C. Nair, Suchart Siengchin, Jyotishkumar Parameswaranpillai e E. K. Radhakrishnan. "Antimicrobial Properties of Bionanocomposites". In Composites Science and Technology, 87–102. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-8578-1_5.
8
Kubacka, Anna, Marcos Fernández-García, María L. Cerrada e Marta Fernández-García. "Titanium Dioxide–Polymer Nanocomposites with Advanced Properties". In Nano-Antimicrobials, 119–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-24428-5_4.
9
DeGroote, Mary Ann, e Ferric C. Fang. "Antimicrobial Properties of Nitric Oxide". In Nitric Oxide and Infection, 231–61. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/0-306-46816-6_12.
10
Sagdic, Osman, e Fatih Tornuk. "Antimicrobial Properties of Organosulfur Compounds". In Dietary Phytochemicals and Microbes, 127–56. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-3926-0_4.
Atti di convegni sul tema "Antimicrobial propertie":
1
Zampino, D., T. Ferreri, C. Puglisi, M. Mancuso, R. Zaccone, R. Scaffaro, Alberto D’Amore, Domenico Acierno e Luigi Grassia. "AG-COMPOSITES WITH ANTIMICROBIAL PROPERTIES". In IV INTERNATIONAL CONFERENCE TIMES OF POLYMERS (TOP) AND COMPOSITES. AIP, 2008. http://dx.doi.org/10.1063/1.2989018.
2
Omar Mohammed, Mohammed Shaymaa, Nicoleta Radu, Verginica Schroder, Rodica Roxana Constantinescu e Narcisa Babeanu. "Antimicrobial Properties of the Bioproducts Formulated with Chitosan and Collagen". In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.ii.17.
Abstract (sommario):
Three types of formulations (stable suspensions) based on collagen, chitosan, limonene and an imidazole derivative were studied through in vitro tests, from the point of view of antimicrobial activity. The results obtained on 4 standardized microorganisms, namely Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus aureus MRSA, Candida albicans, demonstrated that most of the obtained bioproducts have a local effect (inhibition diameters below 15 mm are obtained) and moderate effect (inhibition diameters located under 20 mm), except bioproducts containing collagen, chitosan, limonene and an imidazole derivative (antibiotic reagent) in mass ratio Col:Chit:Lim:CT=1:1:1:0.1, Col:Chit:Lim:CT=1:1:0:0.1 which exhibit a significant antimicrobial effect on Staphylococcus aureus and Staphylococcus aureus MRSA. These two formulations also exhibit significant antimicrobial effects for Candida albicans, for which the average inhibition diameters obtained are greater than 34 mm.
3
HUDIKA, Tomislav, Tomislav CIGULA e Marina VUKOJE. "ANTIMICROBIAL PROPERTIES OF TiO2 NANOCOMPOSITE COATING". In NANOCON 2021. TANGER Ltd., 2021. http://dx.doi.org/10.37904/nanocon.2021.4345.
4
Bazaka, Kateryna, Mohan V. Jacob, Russell J. Crawford e Elena P. Ivanova. "Plasma polymerisation and retention of antibacterial properties of terpinen-4-ol". In Proceedings of the International Conference on Antimicrobial Research (ICAR2010). WORLD SCIENTIFIC, 2011. http://dx.doi.org/10.1142/9789814354868_0034.
5
Varava, Yuliia, Yevhen Samokhin, Anton Savchenko, Kateryna Diedkova, Sergiy Kyrylenko e Viktoriia Korniienko. "Antimicrobial Electrospun Chitosan Nanofibrous Membranes Functionalized with Silver Nanoparticles". In 2021 IEEE 11th International Conference Nanomaterials: Applications & Properties (NAP). IEEE, 2021. http://dx.doi.org/10.1109/nap51885.2021.9568584.
6
Lysenkov, Eduard, Oleksandr Stryutsky e Lyudmila Polovenko. "Development of Nanocomposite Antimicrobial Polymeric Materials Containing Silver Nanoparticles". In 2022 IEEE 12th International Conference Nanomaterials: Applications & Properties (NAP). IEEE, 2022. http://dx.doi.org/10.1109/nap55339.2022.9934675.
7
Rätsep, M., P. Hütt, R. Avi, M. Utt e E. Songisepp. "Antimicrobial properties of Lactobacillus plantarum Tensia (DSM 21380) and Inducia (DSM 21379)". In Proceedings of the International Conference on Antimicrobial Research (ICAR2010). WORLD SCIENTIFIC, 2011. http://dx.doi.org/10.1142/9789814354868_0077.
8
Vakati, Snehal Reddy, Matthew Gacura, Gary Vanderlaan, Xiaoxu Ji, Longyan Chen, Christine A. Saber e Davide Piovesan. "Synthesis of Poly-Lactic Acid by Ring Open Polymerization for Biomedical Applications". In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-113972.
Abstract (sommario):
Abstract Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, it has some drawbacks such as weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The development of synthetic polymers that can release antibiotics and other medicines remains a top research priority. This study proposes a novel approach to produce PLA by converting Brewer’s spent grain (BSG) into lactic acid by bacterial fermentation followed by lactide ring polymerization with a metal catalyst. The elution properties of the PLA polymer are evaluated using modified Kirby-Bauer assays involving the antimicrobial chemotherapeutical, trimethoprim (TMP). Molded PLA polymer disks are impregnated with a known killing concentration of TMP, and the PLA is evaluated as a drug vehicle against TMP-sensitive Escherichia coli. This approach provides a practical means of assessing the polymer’s ability to release antimicrobials, which could be beneficial in exploring new drug-eluting synthetic polymer strategies. Overall, this study highlights the potential of using BSG waste materials to produce valuable biomaterials of medical value with the promise of expanded versatility of synthetic PLA polymers in the field of drug-impregnated tissue grafts.
9
Holubnycha, V., P. Myronov, V. Bugaiov, A. Opanasyuk, O. Dobrozhan, A. Yanovska, M. Pogorielov e O. Kalinkevich. "Effect of Ultrasound Treatment on Chitosan-Silver Nanoparticles Antimicrobial Activity". In 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP). IEEE, 2018. http://dx.doi.org/10.1109/nap.2018.8914849.
10
Todorović, Jovana D., Aleksandra D. Vesić, Nevena N. Petrović e Marijana M. Kosanić. "Antimicrobial potential of mushrooms Macrolepiota procera and Chlorophyllum rhacodes". In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.304t.
Abstract (sommario):
The aim of this study is to investigate the in vitro antimicrobial properties of the acetone extracts of the mushrooms Macrolepiota procera and Chlorophyllum rhacodes. The microdilution method was used to determine the minimum inhibitory concentration (MIC) and assess the antimicrobial effects against three bacterial and ten fungal species. Overall, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi was 0.625 – 20 mg/mL. Extract of C. rhacodes exhibited more powerful antimicrobial properties, with ranged MIC values from 0.625 mg/mL to 10 mg/mL. The Acetone extract of C. rhacodes has shown the most antibacterial activity against S. aureus, while the extract of M. procera has not shown activity against S. aureus as against G. candidum. In comparison to the standard antibiotics as positive controls, the antimicrobial activity of studied extracts was less expressed. The results suggest that mushroom species may be used for pharmaceutical purposes in treating various diseases.
Rapporti di organizzazioni sul tema "Antimicrobial propertie":
1
Choudhary, Ruplal, Victor Rodov, Punit Kohli, John D. Haddock e Samir Droby. Antimicrobial and antioxidant functionalized nanoparticles for enhancing food safety and quality: proof of concept. United States Department of Agriculture, settembre 2012. http://dx.doi.org/10.32747/2012.7597912.bard.
Abstract (sommario):
General concept. The reported 1-year study tested the feasibility ofpreparing antimicrobial and antioxidant nanoparticlesfunctionalized with natural phenolic compounds, as a first step to reach the ultimate goal - improving safely and quality of foods by developing novel antimicrobial and antioxidant food-contacting materials. The secondary objectives of the study were (a) selecting the most promising phenoliccompounds, (b) building nanoparticles with the selected phenolicgrafted on their Surface, and (c) testing antimicrobial and antioxidant properties of these particles. The study was expected to provide a " go/no go" decision as concerning the prospects of phenolic- bound nanoparticles as antimicrobial and antioxidant agents. Results. In course of the feasibility study, curucminwas chosen as the most promising phenoliccompound due to its high antibacterial activity exceeding other tested compounds by at leas one order of magnitude. Lipsome-typephospholipid/polydiacetylene(PDA) nanoparticlesfunctionalizedwith curcuminwere successfully built. The pitfall of limited curcumin amount that could be covalently bound to theparticle surface was circumvented by inclusion of curcunun in the liposome body. It was suggested onthe basis of fluorescence spectroscopy that curcuminwas bound by hydrophobic forces in the bi1ayer periphery of the Liposomesand therefore mightexert a contact effect on microorganisms. The curcumin functionalizednanoparticles(CFN) were shown to have a strong bactericidal activity towards both Gram-negative (E. coli) and Gram-positive (B. ce,·e11s) bacteria, but only limited effect against yeast. Furthermore, beyond the originallyplanned objectives, preliminary trials showed that CFN could be bound to silanized glass surface rendering aנבtiנnicrobial activity to the glass. Tnaddition, the particles showed antioxidantcapacity. Tberefore, it ,vas co11cluded tlוattlוeaims of tlוefeasibility study bad been successfully reached an
2
Poverenov, Elena, Tara McHugh e Victor Rodov. Waste to Worth: Active antimicrobial and health-beneficial food coating from byproducts of mushroom industry. United States Department of Agriculture, gennaio 2014. http://dx.doi.org/10.32747/2014.7600015.bard.
Abstract (sommario):
Background. In this proposal we suggest developing a common solution for three seemingly unrelated acute problems: (1) improving sustainability of fast-growing mushroom industry producing worldwide millions of tons of underutilized leftovers; (2) alleviating the epidemic of vitamin D deficiency adversely affecting the public health in both countries and in other regions; (3) reducing spoilage of perishable fruit and vegetable products leading to food wastage. Based on our previous experience we propose utilizing appropriately processed mushroom byproducts as a source of two valuable bioactive materials: antimicrobial and wholesome polysaccharide chitosan and health-strengthening nutrient ergocalciferol⁽ᵛⁱᵗᵃᵐⁱⁿ ᴰ2⁾. ᴬᵈᵈⁱᵗⁱᵒⁿᵃˡ ᵇᵉⁿᵉᶠⁱᵗ ᵒᶠ ᵗʰᵉˢᵉ ᵐᵃᵗᵉʳⁱᵃˡˢ ⁱˢ ᵗʰᵉⁱʳ ᵒʳⁱᵍⁱⁿ ᶠʳᵒᵐ ⁿᵒⁿ⁻ᵃⁿⁱᵐᵃˡ ᶠᵒᵒᵈ⁻ᵍʳᵃᵈᵉ source. We proposed using chitosan and vitamin D as ingredients in active edible coatings on two model foods: highly perishable fresh-cut melon and less perishable health bars. Objectives and work program. The general aim of the project is improving storability, safety and health value of foods by developing and applying a novel active edible coating based on utilization of mushroom industry leftovers. The work plan includes the following tasks: (a) optimizing the UV-B treatment of mushroom leftover stalks to enrich them with vitamin D without compromising chitosan quality - Done; (b) developing effective extraction procedures to yield chitosan and vitamin D from the stalks - Done; (c) utilizing LbL approach to prepare fungal chitosan-based edible coatings with optimal properties - Done; (d) enrichment of the coating matrix with fungal vitamin D utilizing molecular encapsulation and nano-encapsulation approaches - Done, it was found that no encapsulation methods are needed to enrich chitosan matrix with vitamin D; (e) testing the performance of the coating for controlling spoilage of fresh cut melons - Done; (f) testing the performance of the coating for nutritional enhancement and quality preservation of heath bars - Done. Achievements. In this study numerous results were achieved. Mushroom waste, leftover stalks, was treated ʷⁱᵗʰ ᵁⱽ⁻ᴮ ˡⁱᵍʰᵗ ᵃⁿᵈ ᵗʳᵉᵃᵗᵐᵉⁿᵗ ⁱⁿᵈᵘᶜᵉˢ ᵃ ᵛᵉʳʸ ʰⁱᵍʰ ᵃᶜᶜᵘᵐᵘˡᵃᵗⁱᵒⁿ ᵒᶠ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2, ᶠᵃʳ ᵉˣᶜᵉᵉᵈⁱⁿᵍ any other dietary vitamin D source. The straightforward vitamin D extraction procedure and ᵃ ˢⁱᵐᵖˡⁱᶠⁱᵉᵈ ᵃⁿᵃˡʸᵗⁱᶜᵃˡ ᵖʳᵒᵗᵒᶜᵒˡ ᶠᵒʳ ᵗⁱᵐᵉ⁻ᵉᶠᶠⁱᶜⁱᵉⁿᵗ ᵈᵉᵗᵉʳᵐⁱⁿᵃᵗⁱᵒⁿ ᵒᶠ ᵗʰᵉ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2 ᶜᵒⁿᵗᵉⁿᵗ suitable for routine product quality control were developed. Concerning the fungal chitosan extraction, new freeze-thawing protocol was developed, tested on three different mushroom sources and compared to the classic protocol. The new protocol resulted in up to 2-fold increase in the obtained chitosan yield, up to 3-fold increase in its deacetylation degree, high whitening index and good antimicrobial activity. The fungal chitosan films enriched with Vitamin D were prepared and compared to the films based on animal origin chitosan demonstrating similar density, porosity and water vapor permeability. Layer-by-layer chitosan-alginate electrostatic deposition was used to coat fruit bars. The coatings helped to preserve the quality and increase the shelf-life of fruit bars, delaying degradation of ascorbic acid and antioxidant capacity loss as well as reducing bar softening. Microbiological analyses also showed a delay in yeast and fungal growth when compared with single layer coatings of fungal or animal chitosan or alginate. Edible coatings were also applied on fresh-cut melons and provided significant improvement of physiological quality (firmness, weight ˡᵒˢˢ⁾, ᵐⁱᶜʳᵒᵇⁱᵃˡ ˢᵃᶠᵉᵗʸ ⁽ᵇᵃᶜᵗᵉʳⁱᵃ, ᵐᵒˡᵈ, ʸᵉᵃˢᵗ⁾, ⁿᵒʳᵐᵃˡ ʳᵉˢᵖⁱʳᵃᵗⁱᵒⁿ ᵖʳᵒᶜᵉˢˢ ⁽Cᴼ2, ᴼ²⁾ ᵃⁿᵈ ᵈⁱᵈ not cause off-flavor (EtOH). It was also found that the performance of edible coating from fungal stalk leftovers does not concede to the chitosan coatings sourced from animal or good quality mushrooms. Implications. The proposal helped attaining triple benefit: valorization of mushroom industry byproducts; improving public health by fortification of food products with vitamin D from natural non-animal source; and reducing food wastage by using shelf- life-extending antimicrobial edible coatings. New observations with scientific impact were found. The program resulted in 5 research papers. Several effective and straightforward procedures that can be adopted by mushroom growers and food industries were developed. BARD Report - Project 4784
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Evans, Donald L., Avigdor Eldar, Liliana Jaso-Friedmann e Herve Bercovier. Streptococcus Iniae Infection in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Towards the Pathogen and Vaccine Formulation. United States Department of Agriculture, febbraio 2005. http://dx.doi.org/10.32747/2005.7586538.bard.
Abstract (sommario):
The objectives of the BARD proposal were to determine the mechanisms of nonspecific cytotoxic cells (NCC) that are necessary to provide heightened innate resistance to infection and to identify the antigenic determinants in Streptococcus iniae that are best suited for vaccine development. Our central hypothesis was that anti-bacterial immunity in trout and tilapia can only be acquired by combining "innate" NCC responses with antibody responses to polysaccharide antigens. These Objectives were accomplished by experiments delineated by the following Specific Aims: Specific aim (SA) #1 (USA) "Clone and Identify the Apoptosis Regulatory Genes in NCC"; Specific aim #2 (USA)"Identify Regulatory Factors that Control NCC Responses to S. iniae"; Specific aim #3 (Israel) "Characterize the Biological Properties of the S. iniae Capsular Polysaccharide"; and Specific aim #4 (Israel) "Development of an Acellular Vaccine". Our model of S. iniae pathogenesis encompassed two approaches, identify apoptosis regulatory genes and proteins in tilapia that affected NCC activities (USA group) and determine the participation of S.iniae capsular polysaccharides as potential immunogens for the development of an acellular vaccine (Israel group). We previously established that it was possible to immunize tilapia and trout against experimental S. difficile/iniaeinfections. However these studies indicated that antibody responses in protected fish were short lived (3-4 months). Thus available vaccines were useful for short-term protection only. To address the issues of regulation of pathogenesis and immunogens of S. iniae, we have emphasized the role of the innate immune response regarding activation of NCC and mechanisms of invasiveness. Considerable progress was made toward accomplishing SA #1. We have cloned the cDNA of the following tilapia genes: cellular apoptosis susceptibility (CAS/AF547173»; tumor necrosis factor alpha (TNF / A Y 428948); and nascent polypeptide-associated complex alpha polypeptide (NACA/ A Y168640). Similar attempts were made to sequence the tilapia FasLgene/cDNA, however these experiments were not successful. Aim #2 was to "Identify Regulatory Factors that Control NCC Responses to S. iniae." To accomplish this, a new membrane receptor has been identified that may control innate responses (including apoptosis) of NCC to S. iniae. The receptor is a membrane protein on teleost NCC. This protein (NCC cationic antimicrobial protein-1/ncamp-1/AAQ99138) has been sequenced and the cDNA cloned (A Y324398). In recombinant form, ncamp-l kills S. iniae in vitro. Specific aim 3 ("Characterize the Biological Properties of the S.iniae Capsular Polysaccharide") utilized an in- vitro model using rainbow trout primary skin epithelial cell mono layers. These experiments demonstrated colonization into epithelial cells followed by a rapid decline of viable intracellular bacteria and translocation out of the cell. This pathogenesis model suggested that the bacterium escapes the endosome and translocates through the rainbow trout skin barrier to further invade and infect the host. Specific aim #4 ("Development of an Acellular Vaccine") was not specifically addressed. These studies demonstrated that several different apoptotic regulatory genes/proteins are expressed by tilapia NCC. These are the first studies demonstrating that such factors exist in tilapia. Because tilapia NCC bind to and are activated by S. iniae bacterial DNA, we predict that the apoptotic regulatory activity of S. iniae previously demonstrated by our group may be associated with innate antibacterial responses in tilapia.