Search results for "BACTERIA"

A Comparative Study on Nickel Binding to Hpn-like Polypeptides from Two Helicobacter pylori Strains

2021

Combined potentiometric titration and isothermal titration calorimetry (ITC) methods were used to study the interactions of nickel(II) ions with the N-terminal fragments and histidine-rich fragments of Hpn-like protein from two Helicobacter pylori strains (11637 and 26695). The ITC measurements were performed at various temperatures and buffers in order to extract proton-independent reaction enthalpies of nickel binding to each of the studied protein fragments. We bring up the problem of ITC results of nickel binding to the Hpn-like protein being not always compatible with those from potentiometry and MS regarding the stoichiometry and affinity. The roles of the ATCUN motif and multiple His…

PPI-based triple therapy in the eradication of H. pylori infection.

1999

Fungi and Bacteria in Indoor Cultural Heritage Environments: Microbial-related Risks for Artworks and Human Health

2016

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) p…

Poly(lactic acid)/carvacrol-based materials: preparation, physicochemical properties, and antimicrobial activity

2020

The current demand for new antimicrobial systems has stimulated research for the development of poly(lactic acid)/carvacrol (PLA/CAR)-based materials able to hinder the growth and spread of microorganisms. The eco-friendly characteristics of PLA and cytocompatibility make it very promising in the perspective of green chemistry applications as material for food and biomedical employments. The broad-spectrum biological and pharmacological properties of CAR, including antimicrobial activity, make it an interesting bioactive molecule that can be easily compounded with PLA by adopting the same techniques as those commonly used for PLA manufacturing. This review critically discusses the most comm…

Bacterial growth and biological properties of Cymbopogon schoenanthus and Ziziphus lotus are modulated by extraction conditions

2020

Abstract The present study aims to evaluate the antibacterial activity and biological properties of two traditional Saharian plants (Cymbopogon schoenanthus and Ziziphus lotus). The plant extracts were obtained by using a different combination of extraction methods (conventional vs. ultrasound-assisted) and solvents (water vs. ethanol:water (50:50, v/v)). The antioxidant profile, anti-inflammatory activity and impact on bacterial growth (foodborne and probiotic bacteria) of the obtained extracts were assessed. The plant species showed the hierarchically more important role in determining the biological properties of the extracts, followed by extraction solvent and extraction conditions. Con…

Polyamine conjugates of stigmasterol.

2012

Abstract Three new polyamine conjugates with stigmasterol [(3β,22 E )-stigmasta-5,22-dien-3-ol] were synthesized and subjected to basic antimicrobial and cytotoxic tests. The conjugate derived from spermine, (3β,22 E )-stigmasta-5,22-dien-3-yl 4(12-amino-4,9-diaza-dodecylamino)-4-oxobutanoate ( 5c ), displayed considerable antimicrobial activity on Staphylococcus aureus at low concentration (50 μg mL −1 ). The cytotoxic activity was tested on cells of human T-lymfoblastic leukemia (IC 50  = 35.8 ± 10.3 μM ( 5c ) and IC 50  = 35.9 ± 5.7 μM ( 5b )) and normal human fibroblasts (IC 50  = 38.0 ± 2.8 μM ( 5c ) and IC 50  = 45.5 ± 1.9 μM ( 5b )). Conjugate 5a displayed no activity in both tests.

Antimicrobial peptides from echinoderms as antibiofilm agents: a natural strategy to combat bacterial infections

2014

AbstractIncreased attention has been focused on marine invertebrates as a source of bioactive molecules for biomedical applications. Many bioactive molecules are part of the innate immune system. Some more recently isolated compounds, mainly from the sea urchin and the sea cucumber, are antimicrobial peptides (AMPs) active against Gram-positive and Gram-negative bacteria, and fungi. In this review we described the most recent studies on AMPs isolated from echinoderms. AMPs are small peptides (< 10 kDa) with cationic charge and amphipathic structure. Recently, it was demonstrated that in the coelomocyte lysates of Paracentrotus lividus and Holothuria tubulosa, AMPs possess activity against s…

A New Niche for Anoxygenic Phototrophs as Endoliths

2018

ABSTRACT Anoxygenic phototrophic bacteria (APBs) occur in a wide range of aquatic habitats, from hot springs to freshwater lakes and intertidal microbial mats. Here, we report the discovery of a novel niche for APBs: endoliths within marine littoral carbonates. In a study of 40 locations around Isla de Mona, Puerto Rico, and Menorca, Spain, 16S rRNA high-throughput sequencing of endolithic community DNA revealed the presence of abundant phylotypes potentially belonging to well-known APB clades. An ad hoc phylogenetic classification of these sequences enabled us to refine the assignments more stringently. Even then, all locations contained such putative APBs, often reaching a significant pro…

Human kininogens interact with M protein, a bacterial surface protein and virulence determinant.

1995

Streptococcus pyogenes, the most significant streptococcal species in clinical medicine, expresses surface proteins with affinity for several human plasma proteins. Here we report that kininogens, the precursors to the vasoactive kinins, bind to the surface of S. pyogenes. M protein, a surface molecule and a major virulence factor-in these bacteria, occurs in &amp;gt; 80 different serotypes. Among 49 strains of S. pyogenes, all of different M serotypes, 41 bound radiolabelled kininogens, whereas 6 M protein-negative mutant strains showed no affinity. M protein of most serotypes bind fibrinogen, and among the 55 strains tested, binding of kininogens was closely correlated to fibrinogen bindi…

Microbial and chemical changes in 'Sobrasada' during ripening.

1993

‘Sobrasada’ is a raw-cured product typical of Mallorca (Balearic Islands). Throughout its ripening process the product, like other raw-cured sausages, undergoes a series of chemical and microbial changes which lead to the formation of its desirable final characteristics. In the ‘sobrasada’ studied, the breeds, feeding and casings used in the Balearic Islands were employed. The evolution of different groups of microorganisms was followed: mesophylic aerobic microorganisms, lactic acid bacteria, Enterobacteriaceae, yeasts and moulds, group D Streptococcus, proteolytic microorganisms and lipolytic microorganisms. It was found that the predominant flora, from the beginning to the end, was made …