Search results for "Bacteria"
showing 10 items of 4919 documents
Simulating multilevel dynamics of antimicrobial resistance in a membrane computing model
2019
Membrane computing is a bio-inspired computing paradigm whose devices are the so-called membrane systems or P systems. The P system designed in this work reproduces complex biological landscapes in the computer world. It uses nested “membrane-surrounded entities” able to divide, propagate, and die; to be transferred into other membranes; to exchange informative material according to flexible rules; and to mutate and be selected by external agents. This allows the exploration of hierarchical interactive dynamics resulting from the probabilistic interaction of genes (phenotypes), clones, species, hosts, environments, and antibiotic challenges. Our model facilitates analysis of several aspects…
New Bioactive Peptides from the Mediterranean Seagrass Posidonia oceanica (L.) Delile and Their Impact on Antimicrobial Activity and Apoptosis of Hum…
2023
The demand for new molecules to counter bacterial resistance to antibiotics and tumor cell resistance is increasingly pressing. The Mediterranean seagrass Posidonia oceanica is considered a promising source of new bioactive molecules. Polypeptide-enriched fractions of rhizomes and green leaves of the seagrass were tested against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Escherichia coli), as well as towards the yeast Candida albicans. The aforementioned extracts showed indicative MIC values, ranging from 1.61 μg/mL to 7.5 μg/mL, against the selected pathogens. Peptide fractions were further analyzed thr…
Prevenzione dell’occlusione delle protesi biliari mediante somministrazione di levofloxacina e acido ursodesossicolico.
2004
One of the main advances in biliopancreatic endoscopic therapy has been the ability to palliate patients with biliary obstruction by placement of a stent during ERCP, but this is often complicated by clogging of the stent with subsequent jaundice and/or cholangitis. Stent clogging may be caused by microbiological adhesion and biliary stasis. Therefore, the use of antibiotics and choleretic agents such as levofloxacin and ursodeoxycholic acid has been investigated to see whether they prolong stent patency. Ninety patients with strictures of the biliary tract and untreatable macrolithiasis with endoscopically inserted stents were randomized into two groups: 49 subjects in group 1 (levofloxaci…
Síntesis de nuevas isoquinoleínas 1-sustituidas con actividad antibacteriana y antifúngica o dopaminérgica
2015
La Naturaleza ha proporcionado durante décadas una ingente cantidad de metabolitos secundarios activos (MSA) con muy diversas aplicaciones terapéuticas. Durante décadas, nuestro grupo de investigación se ha centrado tanto en el aislamiento de MSA de plantas pertenecientes a la familia de las Annonáceas como en el desarrollo de análogos estructurales de algunos MSA, especialmente acetogeninas y alcaloides isoquinoleínicos, que pudieran ser biológicamente activos. Considerando estos hechos se propuso en la presente Tesis Doctoral la consecución de los siguientes objetivos: 1- Estudio de los distintos tipos de MSA presentes en Annonáceas que han servido de inspiración para el desarrollo de nue…
Composition and antimicrobial activity of the essential oil of Achillea falcata L. (Asteraceae).
2005
The composition of the essential oil from aerial parts of Achillea falcata L. (Asteraceae) growing wild in Lebanon was analysed by GC and GC–MS; 58 compounds, representing 94.4% of the oil, were identified. Isomers of the cyclobutane ethanol, 1-methyl-2-(1-methylethenyl), grandisol (21.4%) and fragranol (16.8%) were the main components of the oil. Also abundant were artemisia ketone (5.2%), terpinen-4-ol (4.5%) and 1,8-cineole (4.0%). The essential oil shows inhibitory activity mainly against Gram-positive bacteria.
A synthetic derivative of antimicrobial peptide holothuroidin 2 from mediterranean sea cucumber (Holothuria tubulosa) in the control of Listeria mono…
2019
Due to the limited number of available antibiotics, antimicrobial peptides (AMPs) are considered antimicrobial candidates to fight difficult-to-treat infections such as those associated with biofilms. Marine environments are precious sources of AMPs, as shown by the recent discovery of antibiofilm properties of Holothuroidin 2 (H2), an AMP produced by the Mediterranean sea cucumber Holothuria tubulosa. In this study, we considered the properties of a new H2 derivative, named H2d, and we tested it against seven strains of the dangerous foodborne pathogen Listeria monocytogenes. This peptide was more active than H2 in inhibiting the growth of planktonic L. monocytogenes and was able to interf…
PVC silver zeolite composites with antimicrobial properties
2011
Poly(vinyl chloride) (PVC) composites containing increasing amounts (2-20%, w/w) of silver zeolite (SZ) were prepared by melt mixing and characterized by thermal, mechanical and rheological analyses. The addition of large amount of SZ did not influence the processability and the formability of the composites, if compared to neat plasticized PVC. The antibacterial activity of PVC SZ composites was tested on Escherichia coli and Staphylococcus epidermidis and resulted promising both in culture broth and on agar plate and also in sterile urine seeded with these strains, for simulation purposes. In sterile urine, composites induced a significant reduction (4-6 log units) of viability of both st…
Supramolecular Structure and Antimicrobial Activity of Ni(II) Complexes with s-Triazine/Hydrazine Type Ligand
2023
The two complexes, [Ni(DPPT)2](NO3)2*1.5H2O (1) and [Ni(DPPT)(NO3)Cl].EtOH (2), were synthesized using the self-assembly of (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine (DPPT) with Ni(NO3)2*6H2O in the absence and presence of NiCl2*6H2O, respectively. In both cases, the neutral tridentate DPPT ligand is found coordinated to the Ni(II) via three N-atoms from the hydrazone, pyridine and s-triazine rings. Hence, the homoleptic complex 1 has a NiN6 hexa-coordination environment while two NO3− are counter anions in addition to one-and-a-half crystallized hydration water molecules are found acting as an outer sphere. The heteroleptic complex 2 has a NiN3O…
Inspired by nature: Fiber networks functionalized with tannic acid and condensed tannin-rich extracts of Norway spruce bark show antimicrobial effica…
2023
This study demonstrated the antibacterial and antiviral potential of condensed tannins and tannic acid when incorporated into fiber networks tested for functional material purposes. Condensed tannins were extracted from industrial bark of Norway spruce by using pressurized hot water extraction (PHWE), followed by purification of extracts by using XADHP7 treatment to obtain sugar-free extract. The chemical composition of the extracts was analyzed by using HPLC, GC‒MS and UHPLC after thiolytic degradation. The test matrices, i.e., lignocellulosic handsheets, were produced and impregnated with tannin-rich extracts, and tannic acid was used as a commercial reference. The antibacterial and antiv…
Modification of face masks with zeolite imidazolate framework-8
2022
The worldwide spread of the SARS-CoV-2 virus has continued to accelerate, putting a considerable burden on public health, safety, and the global economy. Taking into consideration that the main route of virus transmission is via respiratory particles, the face mask represents a simple and efficient barrier between potentially infected and healthy individuals, thus reducing transmissibility per contact by reducing transmission of infected respiratory particles. However, long-term usage of a face mask leads to the accumulation of significant amounts of different pathogens and viruses onto the surface of the mask and can result in dangerous bacterial and viral co-infections. Zeolite imidazolat…