The adherence of Pseudomonas fluorescens to marble, granite, synthetic polymers, and stainless steel

The adherence of Pseudomonas fluorescens cells to nine food-processing contact surfaces was evaluated using the plate-count method. The surfaces include marble, granite, stainless steel, polyvinyl chloride, polyurethane, and silicone-coated cloth, which have been used only in a few studies concerning bacterial adherence. The number of cells adhered to the surfaces increased with contact time reaching 5.0-6.1 log CDM.cm-2 after 10 hours, which can be considered a well established adherence process. The number of adhered cells doubled in 29.5 minutes and 23.5 minutes on stainless steel and thin polyvinyl chloride-coated cloth, respectively. For the other surfaces, this value was 9.8 minutes on average. Marble, granite, thick polyvinyl-coated cloth, double-faced rugous polyurethane, and silicone-coated cloth were not different (p < 0.05) in their ability to adhere cells (CFU/cm²) after 2 and 10 hours. The surfaces that had higher percentage of similarity in the adhesion level and higher log CFU/cm² of adhered cells were double-faced rugous polyurethane, silicone-coated cloth, and granite. The surfaces showed very different microtopography characteristics when viewed using scanning electron microscopy. This experiment showed the importance of using appropriate materials for food contact during processing, which will affect the cleaning and sanitation procedures.

Conversion of hydroxycinnamic acids into volatile phenols in a synthetic medium and in red wine by Dekkera bruxellensis

The conversion of p-coumaric acid, ferulic acid, and caffeic acid into 4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol was studied in Dekkera bruxellensis ISA 1791 under defined conditions in a synthetic medium and in a red wine. Liquid chromatography (HPLC-DAD) was used to quantify the phenolic acids, and gas chromatography (GC) coupled to a FID detector was used to quantify volatile phenols using a novel analytical methodology that does not require sample derivatization. Identification was achieved by gas chromatography-mass detection (GC-MS). The results show that phenolic acids concentration decreases while volatile phenols concentration increases. The proportion of caffeic acid taken up by Dekkera bruxellensis is lower than that for p-coumaric or ferulic acid; therefore less 4-ethylcatechol is formed. More important, 4-ethylcathecol synthesis by Dekkera bruxellensis in wine has never been demonstrated so far. These results contribute decisively to a better understanding of the origin of the volatile phenols in wines. The accumulation of these compounds in wine is nowadays regarded as one of the key factors of quality control.

Peptide separation of commercial fermented milk during refrigerated storage

Milk is an important source of bioactive compounds. Many of these compounds are released during fermentation and refrigerated storage. The aim of this study was to determine the release of peptides by lactic acid bacteria in commercial fermented milk during refrigerated storage. The size and profile of peptides were analyzed by polyacrylamide gel electrophoresis and sizeexclusion HPLC. During electrophoresis, it was observed that the peptides were released from caseins, whereas β-lactoglobulin was the whey protein with the highest degradation. HPLC analysis confirmed the pattern of peptide formation observed in electrophoresis. Two fractions lower than 2 kDa with aromatic amino acids in their structure were separated. These results were consistent with those reported for structures of peptides with antihypertensive activity. Therefore, the presence of aromatic amino acids in the peptide fractions obtained increases the likelihood of finding peptides with such activity in refrigerated commercial fermented milk. In conclusion, during cold storage, peptides with different molecular weights are released and accumulated. This could be due to the action of proteinases and peptidases of the proteolytic system in lactic acid bacteria.

Cytotoxic and genotoxic potential of liquid synthetic food flavorings evaluated alone and in combination

This study aimed to evaluate the cytotoxic and genotoxic potential of food flavorings (Strawberry, Condensed Milk and Chocolate) on Allium cepa meristematic root cells, with exposure times of 24 and 48 hours. Cytotoxic and mutagenic potential were evaluated separately at doses of 0.2, 0.4 and 0.6 ml and in combination, in which for each dose, the same dose of one other flavoring was combined. The results were analyzed by the Chi-square test (p <0.05). The Strawberry flavor in both exposure times and the three studied doses, the Condensed Milk at 0.6 ml in the 48 hour exposure time, the Chocolate flavor at 0.4 ml, exposure time of 48 hours, and at 0.6 ml, in both exposure times and all treatments with combined doses, significantly reduced the cell division rate, proving to be cytotoxic. No treatment resulted in a significant number of cellular aberrations in A. cepa cells, therefore, the flavorings, under the conditions studied, were non- mutagenic.

Ultrastructural changes of Fusobacterium nucleatum as a defense mechanism against human neutrophil peptide-1 - A Transmission Electron Microscopy (TEM) study

Aims: The aim of this work was to assess the ultrastructural changes, cellular proliferation, and the biofilm formation ability of F. nucleatum as defense mechanisms against the effect of HNP-1. Materials and methods: The type strain of F. nucleatum (ssp. nucleatum ATCC 25586) and two clinical strains (ssp. polymorphum AHN 9910 and ssp. nucleatum AHN 9508) were cultured and incubated with four different test concentrations of recombinant HNP-1 (1, 5, 10 and 20 µg/ml) and one control group (0 µg/ml). Bacterial pellets from each concentration were processed for TEM imaging. Planktonic growth was assessed and colony forming units (CFU) were measured to determine the cellular proliferation. Scrambled HNP-1 was used for confirmation. Results: TEM analyses revealed a decrease in the outer membrane surface corrugations and roughness of the strain AHN 9508 with increasing HNP-1 concentrations. In higher concentrations of HNP-1, the strain AHN 9910 showed thicker outer membranes with a number of associated rough vesicles attached to the outer surface. For ATCC 25586, the treated bacterial cells contained higher numbers of intracellular granules with increasing the peptide concentration. Planktonic growth of the two clinical strains were significantly enhanced (P<0.001) with gradually increased concentrations of HNP-1. None of the planktonic growth results of the 3 strains incubated with the scrambled HNP-1 was statistically significant. HNP-1 decreased the biofilm formation of the two clinical strains, AHN 9910 and 9508, significantly (P<0.01 and P<0.001; respectively). Conclusions: The present in vitro study demonstrates that F. nucleatum has the ability to withstand the lethal effects of HNP-1 even at concentrations simulating the diseased periodontium in vivo. The increase in planktonic growth could act as defense mechanisms of F. nucleatum against HNP-1.

"A1 alkuperäisartikkeli tieteellisessä aikauslehdessä" : uusien julkaisukäytänteiden omaksuminen ihmistieteissä 2000-luvulla

Referee-artikkeli

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 109 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 108 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 108 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 109 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 109 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le lys dans la vallée : drame en cinq actes, en prose d'après H. de Balzac. [suivi de] Un homme entre deux airs : comédie-vaudeville en un acte. Livr. 108 / par MM. Théodore Barrière et A. de Beauplan ; par MM. Dealcour, Montjoye et Larounat

Collection : Théâtre contemporain illustré ; 108e et 109e livraisons

Le vieux caporal : drame en cinq actes. [suivi de] Diane de lys et de camélias, ou La femme du monde légère, liée à un homme bilieux qui n'entend pas la plaisanterie : grande parodie en 3 petits tableaux. Livr. 121 / par MM. Dumanoir et d'Ennery ; par MM. Delacour et Lambert Thiboust

Collection : Théâtre contemporain illustré ; 121e et 122e livraisons

Le vieux caporal : drame en cinq actes. [suivi de] Diane de lys et de camélias, ou La femme du monde légère, liée à un homme bilieux qui n'entend pas la plaisanterie : grande parodie en 3 petits tableaux. Livr. 122 / par MM. Dumanoir et d'Ennery ; par MM. Delacour et Lambert Thiboust

Collection : Théâtre contemporain illustré ; 121e et 122e livraisons