Search results for "biologia generale"

Biofilm Related to Animal Health, Zoonosis and Food Transmitted Diseases: Alternative Targets for Antimicrobial Strategy?

2012

The biofilm is a complex community of microbial cells that are associated with a surface and enclosed in a self-produced biopolymer matrix. Such structured community is a response of bacteria to a signal system named quorum sensing (QS) constituted by inter-cell communication through the production of small molecules called autoinducers (AIs) that trigger a cascade of events in gene expression. When the concentration of the AIs molecules reach a certain threshold, the bacterial population acts as a single organism, collectively expressing virulence or biofilm forming genes. Gram-positive bacteria use modified oligopeptides as QS effectors molecules.

Discovery of a New Class of Sortase A Transpeptidase Inhibitors to Tackle Gram-positive Pathogens: 2-Phenylhydrazonoalkanoic Acid Derivatives

2015

There is an urgent need of anti-virulence agents effective in the prevention or eradication of biofilms that are intrinsically resistant to conventional antibiotics. If we consider that the first step of staphylococcal pathogenesis and of biofilm formation is the bacterial adhesion, promoted by the surface exposed proteins at the cell wall, we believe that new anti-virulence agents could be developed by using as a target the Sortase A (SrtA), the enzyme responsible of linking surface exposed proteins to peptidoglycan. Therefore, SrtA inhibitors could act as anti-adhesion agents useful to prevent Gram positive virulence mechanisms as well as a virulence mechanism based on biofilm formation. …

New Anti-Adhesion Agents In The Development of Antivirulence Drugs

2015

Gram-positive bacteria are a significant cause of nosocomial and community-acquired infections associated with diseases of high morbidity and mortality. Moreover, antibiotic resistance of important Gram-positive pathogens, such as Staphylococcus aureus, Streptococcus pneumoniae and Enterococcus faecalis is one of the major worldwide health problems. Over the last decade, many studies have focused on agents that target the virulence of important pathogens without killing or inhibiting their growth therefore imposing limited selective pressure to promote the development and spread of resistance mechanisms [1]enterococci and streptococci, sortase A plays a critical role in Gram-positive bacter…

Stafilococchi: causa di mastite

2011

Staphylococcus aureus è un batterio che può provocare mastite. Negli ultimi anni sono stati isolati Stafilococchi resistenti a molti degli antibiotici usati in terapia. Il presente lavoro ha lo scopo di caratterizzare gli Stafilococchi circolanti in Sicilia per prevenire la diffusione di batteri patogeni resistenti

ANTIMICROBIAL AND ANTIBIOFILM ACTIVITY OF A PEPTIDE IDENTIFIED IN THE SEAGRASS POSIDONIA OCEANICA

2022

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…

Staphylococcal Biofilms: Challenges in the discovery of Novel Anti-Infective Agents

2011

Antimicrobial and antioxidant supramolecular ionic liquid gels from biopolymer mixtures

2023

In this work, we describe the preparation and characterization of supramolecular ionic liquid gels based on binary mixtures of biopolymers, comprising chitosan, chitin, cellulose and lignin. The gels were obtained in ionic liquids differing in the cation or the anion, with no need for a cross-linking agent or acid treatment. The materials obtained were characterized for the minimum gelation concentration, porosity, swelling and rheological properties, finding a prominent influence of the nature of the ionic liquid anion. Then, we investigated the ability of the gels to scavenge free radicals, finding that the gels exhibit a higher antioxidant ability than their individual components. Moreov…

Antimicrobial and antiproliferative activity of Athamanta sicula L. (Apiaceae).

2010

Background: Athamanta sicula L., a member of Apiaceae, is an annual perennial herb and it is known in Sicilian popular medicine with the name of “spaccapietre” (rock splitters), because fresh roots infusions are indicated as diuretic and used in the treatment of diseases of the urinary tract, and to dissolve kidney stones. Materials and Methods: Acetone extracts of leaves, flowers, and stems of A. sicula L. were investigated in vitro for antibacterial and cytotoxic activities. Antimicrobial activity was carried out against bacterial and fungal strains and antiproliferative activity against a group of human cancer cell lines (K-562, NCI-H460, and MCF-7). Results: All acetone extracts, apiol …

Preliminary results for application of culture-independent molecular methods to olive brines bacterial communities.

2006

Transformation of green table olives requires a brining stage during which olives ferment. In naturally transformed olives, both flavour improvement and debittering are associated to fermentation. Because of brine features, naturally occurring bacteria and yeasts are progressively selected by the high salt concentration, low pH and phenolic compounds with antimicrobial activity. The establishment of an adequate fermenting microflora is essential to obtain a good and safe product; then, during transformation, control of chemical and microbiological parameters is crucial. Currently, microflora is periodically monitored by plate-counting of main groups. These routine analyses, however, don’t s…