Search results for "Bacterial activity"
showing 10 items of 178 documents
Effect of pH and nitrite concentration on nitrite oxidation rate
2011
The effect of pH and nitrite concentration on the activity of the nitrite oxidizing bacteria (NOB) in an activated sludge reactor has been determined by means of laboratory batch experiments based on respirometric techniques. The bacterial activity was measured at different pH and at different total nitrite concentrations (TNO 2). The experimental results showed that the nitrite oxidation rate (NOR) depends on the TNO 2 concentration independently of the free nitrous acid (FNA) concentration, so FNA cannot be considered as the real substrate for NOB. NOB were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity wa…
Salmo salar fish waste oil: Fatty acids composition and antibacterial activity
2020
Background and aims Fish by-products are generally used to produce fishmeal or fertilizers, with fish oil as a by-product. Despite their importance, fish wastes are still poorly explored and characterized and more studies are needed to reveal their potentiality. The goal of the present study was to qualitatively characterize and investigate the antimicrobial effects of the fish oil extracted from Salmo salar waste samples and to evaluate the potential use of these compounds for treating pathogen infections. Methods Salmo salar waste samples were divided in two groups: heads and soft tissues. Fatty acids composition, and in particular the content in saturated (SAFAs), mono-unsaturated (MUFA…
Chemical composition of the essential oil of Phagnalon saxatile (L.) Cass. (Asteraceae) growing wild in Southern Italy
2005
Abstract The essential oil from aerial parts of Phagnalon saxatile (L.) Cass. (Asteraceae) was obtained by hydrodistillation. The oil content was 0.15% (v/w), on a dry weight basis. The oil composition was analyzed by GC and GC/MS. Altogether 66 compounds were identified accounting for 93.2% of the oil. Sesquiterpenes represent the 23.9% of the oil. In the oil were also present fatty acids (21.8%) and waxes (19.3%). The oil shows no antibacterial activity.
Mechanism of Antibacterial Activity via Morphology Change of α-AgVO3: Theoretical and Experimental Insights
2017
The electronic configuration, morphology, optical features, and antibacterial activity of metastable α-AgVO3 crystals have been discussed by a conciliation and association of the results acquired by experimental procedures and first-principles calculations. The α-AgVO3 powders were synthesized using a coprecipitation method at 10, 20, and 30 °C. By using a Wulff construction for all relevant low-index surfaces [(100), (010), (001), (110), (011), (101), and (111)], the fine-tuning of the desired morphologies can be achieved by controlling the values of the surface energies, thereby lending a microscopic understanding to the experimental results. The as-synthesized α-AgVO3 crystals display a …
The presence of conifer resin decreases the use of the immune system in wood ants.
2008
5 pages; International audience; 1. Wood ants ( Formica paralugubris ) incorporate large amounts of solidified conifer resin into their nest, which reduces the density of many bacteria and fungi and protects the ants against some detrimental micro-organisms. By inducing an environment unfavourable to pathogens, the presence of resin may allow workers to reduce the use of their immune system. 2. The present study tested the hypothesis that the presence of resin decreases the immune activity of wood ants. Specifically, three components of the humoral immune defences of workers kept in resin-rich and resin-free experimental nests (antibacterial, lytic, and prophenoloxidase activities) were com…
Different a-casein association states and their interaction with lipid vesicles to study antibacterial activity
The interactions between caseins and lipid membranes are fundamental for the physiological function of these proteins. Moreover, the understanding of the underlying molecular mechanisms is of great interest for the development of new casein derived antimicrobial peptides. Indeed, it was already shown that peptides derived from caseins possess antibacterial activity but their mechanisms of action is still debated. Here, we present an experimental study on the interaction between model lipid membranes and a-casein by means of spectroscopy and fluorescence microscopy techniques. a-casein is an unfolded protein that due to its amphiphilic nature is known to self-assembly into non-stable micella…
Essential oils as multi-target compounds for novel food safety strategies
This research work has been developed in the context of the potencial applications of essential oils as multi-target compounds for novel food safety strategies, such as active packaging technologies. Essential oils are aromatic oils derived from plants and usually extracted by hydrodistillation when intended to be used in food. There is an increasing interest in the antimicrobial properties of essential oils due to the possibility of using them to replace ‘synthetic’ preservatives in food or, in general, to reduce viable numbers of pathogens along the food chain.
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…
Biomineralization events in Recent volcanic and sedimentary settings: textural features and isotope signatures.
2008
Composition and Antimicrobial Activity of Essential Oil ofAnthemis tenuisectaBall
2007
Abstract The Chemical composition of the essential oil of Anthemis tenuisecta Ball. (Anthemideae) was analyzed by gas Chromatography-mass spectrometry (GC-MS). Forty eight components accounting for 89.5 % of the oil were identified, being camphor (17.5 %), 6-methyl-5-hepten-2-one (17.1 %), borneol (11.5 %), sesquicineole (11%) and camphene (5.7 %) the main compounds. In the antibacterial diffusion assay, the oil showed activity against Gram-positive bacteria.