Listeria monocytogenes is a Gram positive, aerobic, facultative anaerobic and nonacid fast bacterium, which can cause the disease listeriosis in both human and animals. It is widely distributed thoroughout the environment and has been isolated from various plant and animal food products associated with listeriosis outbreaks.

Contaminated ready-to-eat food products such as gravad and cold-smoked salmon and rainbow trout have been associated with human listeriosis in Sweden. The aim of this study was to analyse the occurrence and level of L. monocytogenes in
gravad and cold-smoked salmon (Salmo salar) products packed under vacuum or modified atmosphere from retail outlets in Sweden. Isolated strains were characterized by serotyping and the diversity of the strains within and between
producers were determined with PFGE (Pulsed-field gel electrophoresis). The characterized fish isolates were compared with previously characterized human strains.
L. monocytogenes was isolated from 11 (three manufacturers) of 56 products analysed. This included gravad salmon products from three manufacturers and cold-smoked salmon from one manufacturer. The highest level of L. monocytogenes found was 1500 cfu/g from a cold-smoked salmon product but the level was low (<100 cfu/g) in most of the products. Serovar 1/2a was predominant,
followed by 4b. Three products of gravad salmon harboured more than one serovar. PFGE typing of the 56 salmon isolates detected five Asc I types: four types were identical to human clinical strains with Asc I and one was identical and one was closely related to human clinical strains with Apa I. Isolation of identical or closely related L. monocytogenes strains from human clinical cases of listeriosis and gravad and cold-smoked salmon suggested that these kinds of products are possible sources of listeriosis in Sweden. Therefore, these products should be considered risk products for human listeriosis.

Listeria monocytogenes, a food-borne pathogen

Increased optical nonlinearities of graphene nanohybrids covalently functionalized by axially-coordinated porphyrins

Herein, we report a solvent- and metal-free methodology for the alkoxy-chalcogenylation of styrenes, using molecular iodine as a catalyst, DMSO as a stoichiometric oxidant, and different nucleophiles under microwave irradiation. This eco-friendly approach afforded the desired products in good to excellent yields in only 10 min. In addition, using the same protocol, we carried out the cyclization reaction of relevant molecules, such as lapachol derivatives.

Catalytic chalcogenylation under greener conditions: a solvent-free sulfur- and seleno-functionalization of olefins via I2/DMSO oxidant system.

2-Azabicyclo[2.2.1]hept-5-en-3-one: chemical profile of a versatile synthetic building block and its impact on the development of therapeutics.

Donor modification of nonlinear optical chromophores: Synthesis, characterization, and fine-tuning of chromophores' mobility and steric hindrance to achieve ultra large electro-optic coefficients in guest–host electro-optic materials

Some novel (phenyl-diazenyl)phenols (4a–m) were designed and synthesized to be evaluated for their antibacterial activity. Starting from an active previously-synthesized azobenzene chosen as lead compound, we introduced some modifications and optimization of the structure, in order to improve solubility and drug conveyance. Structures of all newly-synthesized compounds were confirmed by 1H nuclear magnetic resonance (NMR), mass spectrometry, and UV-Vis spectroscopy. Antibacterial activity of the new compounds was tested with the dilution method against the bacteria strains Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa PAO1. All the compounds were selectively active against Gram-positive bacteria. In particular, compounds 4d, 4h, and 4i showed the highest activity against S. aureus and Listeria monocytogenes, reaching remarkable MIC100 values of 4 μg/mL and 8 μg/mL. The relationship between antimicrobial activity and compound structure has suggested that the presence of hydroxyl groups seems to be essential for antimicrobial activity of phenolic compounds.

https://www.mdpi.com/1420-3049/22/8/1372/pdf

Synthesis and Antimicrobial Studies of New Antibacterial Azo-Compounds Active against Staphylococcus aureus and Listeria monocytogenes

Tridentate ligands are simple low-cost pincers, easy to synthetize, and able to guarantee stability to the derived complexes. On the other hand, due to its unique mix of structural and optical properties, zinc(II) ion is an excellent candidate to modulate the emission pattern as desired. The present work is an overview of selected articles about zinc(II) complexes showing a tuned fluorescence response with respect to their tridentate ligands. A classification of the tridentate pincers was carried out according to the binding donor atom groups, specifically nitrogen, oxygen, and sulfur donor atoms, and depending on the structure obtained upon coordination. Fluorescence properties of the ligands and the related complexes were compared and discussed both in solution and in the solid state, keeping an eye on possible applications.

/pdf/the-role-of-zinc-ii-ion-in-fluorescence-tuning-of-tridentate-16hwarx3q9.pdf

The Role of Zinc(II) Ion in Fluorescence Tuning of Tridentate Pincers: A Review.

Evaluating the biological properties of synthetic 4-nitrophenyl functionalized benzofuran derivatives with telomeric DNA binding and antiproliferative activities.

Fluorescence pH-dependent sensing of Zn(II)by a tripodal ligand. A comparative X-ray and DFT study

Some novel (phenyl-diazenyl)phenols 3a–g were designed and synthesized to be evaluated for their antimicrobial activity. A previously synthesized molecule, active against bacteria and fungi, was used as lead for modifications and optimization of the structure, by introduction/removal or displacement of hydroxyl groups on the azobenzene rings. The aim of this work was to evaluate the consequent changes of the antimicrobial activity and to validate the hypothesis that, for these compounds, a plausible mechanism could involve an interaction with protein receptors, rather than an interaction with membrane. All newly synthesized compounds were analyzed by 1H-NMR, DSC thermal analysis and UV-Vis spectroscopy. The in vitro minimal inhibitory concentrations (MIC) of each compound was determined against Gram-positive and Gram-negative bacteria and Candida albicans. Compounds 3b and 3g showed the highest activity against S. aureus and C. albicans, with remarkable MIC values of 10 µg/mL and 3 µg/mL, respectively. Structure-activity relationship studies were capable to rationalize the effect of different substitutions on the phenyl ring of the azobenzene on antimicrobial activity.

/pdf/structure-modification-of-an-active-azo-compound-as-a-route-pjne1t72f4.pdf

Rosita Diana

Papers

Synthesis and Antimicrobial Studies of New Antibacterial Azo-Compounds Active against Staphylococcus aureus and Listeria monocytogenes

The Role of Zinc(II) Ion in Fluorescence Tuning of Tridentate Pincers: A Review.

Evaluating the biological properties of synthetic 4-nitrophenyl functionalized benzofuran derivatives with telomeric DNA binding and antiproliferative activities.

Fluorescence pH-dependent sensing of Zn(II)by a tripodal ligand. A comparative X-ray and DFT study

Structure Modification of an Active Azo-Compound as a Route to New Antimicrobial Compounds