Safety characterisation and inhibition of fungi and bacteria by a novel multiple enterocin-producing Enterococcus lactis 4CP3 strain.

This study aims to characterise a potential bacteriocinogenic lactic acid bacterial strain isolated from a raw pink shrimp (Palaemon serratus) and evaluate its safety aspect. The strain designated as 4CP3 was noted to display antibacterial activities (P < 0.05) against Gram-positive and Gram-negative foodborne pathogens (Listeria monocytogenes and Pseudomonas aeruginosa) and some filamentous fungi (e.g. Aspergillus niger A79). Phenotypic and molecular techniques as well as phylogenetic analysis identified the isolate 4CP3 as Enterococcus lactis. Its produced antimicrobial substance was determined as a bacteriocin that was stable over a wide range of pH (2-10) and after heating at 100 °C for 15 min. The maximum bacteriocin production was 1400 AU/ml recorded after 12 h of incubation in de Man, Rogosa and Sharpe (MRS) broth medium at 30 °C. The mode of action of the bacteriocin produced by 4CP3 strain was identified as bactericidal against L. monocytogenes EGDe 107776 and P. aeruginosa ATCC 27853. By specific PCR amplifications, E. lactis 4CP3 was shown to produce the enterocins A, B and P. To our knowledge, this feature is newly described for E. lactis strain isolated from raw shrimps. Regarding safety aspect of E. lactis 4CP3, it has been demonstrated that this strain was not haemolytic, gelatinase negative, sensitive to vancomycin, and free of common antibiotic resistance genes and virulence factors. Therefore, it may be useful as a safe natural agent in preservation of foods or as a new probiotic strain in food and feed.

Synthesis and cytotoxicity of new potential intercalators based on tricyclic systems of some pyrimido[5,4-c]cinnoline and pyrimido[5,4-c]quinoline derivatives. Part I.

Pyrimido[5,4-c]cinnoline and pyrimido[5,4-c]quinoline derivatives have been tested as potential intercalators. All of them embody stuctural properties alike to afford intercalating activity. Their cytotoxicity was determined on the two human leukemia cell lines, the promyelocytic HL-60 and the lymphoblastic NALM-6. The viability of cells exposed continuously to tested compounds was estimated by the trypan-blue exclusion assay. IC50 data for the NALM-6 cell line are lower than for the HL-60 cell line, what suggested that the HL-60 leukemia cells are more resistant to toxic action of tested compounds. All compounds exerted moderate cytotoxic activity. The compounds were analyzed with the HyperChem/ChemPlus software trying to find basic structure-activity relationships.

A novel one-step drug-loading procedure for water-soluble amphiphilic nanocarriers.

PURPOSE: The lack of water-solubility hampers the use of many potent pharmaceuticals. Polymeric micelles are self-assembled nanocarriers with versatile properties that can be engineered to solubilize, target, and release hydrophobic drugs in a controlled-release fashion. Unfortunately, their large-scale use is limited by the incorporation methods available, especially when sterile dosage forms are sought. METHODS: In this manuscript, we describe a straightforward, economical, and innovative drug-loading procedure that consists in dissolving both the drug and an amphiphilic diblock copolymer in a water/tert-butanol mixture that is subsequently freeze-dried. RESULTS: We demonstrate that monodisperse 20-60 nm-sized drug-loaded polymeric micelles are produced directly and spontaneously upon rehydration of the freeze-dried cake. To establish the proof-of-principle, two hydrophobic taxane derivatives were solubilized in the micelles, and their partition coefficient was determined. CONCLUSIONS: This approach is efficient yet astonishingly simple and may be of great interest for scientists working in nanotechnology and pharmaceutical sciences.