Peptidase profiles of Pseudomonas fluorescens: identification and properties.

The cell-associated peptidase profiles of 12 strains of Pseudomonas fluorescens (ATCC 948 and 11 related biotypes) were examined. Employing Analytab system API ZYM, a general, strong peptidase activity was detected using L-lysyl-, L-pyrrolidonyl-, L-arginyl-, L-alanyl-, and glycyl-glycyl-beta-naphthylamides as substrates. Conversely, L-tyrosyl-, L-phenylalanyl-, L-histidyl-, L-prolyl-, gamma-L-glutamyl-beta-naphthylamides substrates were hydrolyzed by only a few strains. The peptidases were active, therefore, on substrates responsible for the bitter taste in dairy products. Properties of hydrolytic systems showed no significant changes in the enzymatic profiles when cells were grown on different fermentation media. Enzyme activity was relatively stable during refrigerated (5 degrees C) and frozen (-18 degrees C) storage. The peptidases of P. fluorescens ATCC 948, considered as reference, and strain 22 were identified on Pro-beta-naphthylamides by Michaelis constant values of .528 and .394 mM, respectively, and by different optimal pH and temperature activity on Leu- and Pro-beta-naphthylamides. The peptidase activity on Gly-Phe-beta-naphthylamide in P. fluorescens 30 had optimal values at pH 7.50 and 45 degrees C. These results confirm the relations defined in the enzymatic identification phase and suggest the presence of any analogous peptidases in the biovars of P. fluorescens considered

Visualizzazione volumetrica diretta interattiva con effetti di illuminazione mediante Register Combiner OpenGL

In diversi ambiti scientifici e industriali, la sempre più frequente acquisizione di dati volumetrici fa crescere la domanda di potenti tool per la loro visualizzazione, analisi e manipolazione interattiva. In questo rapporto presentiamo una tecnica di visualizzazione volumetrica diretta che consente l’applicazione del modello di illuminazione di Phong in tempo reale. La tecnica implementa il modello ottico di assorbimento + emissione eseguendo in tempo reale campionamento, mapping e integrazione delle proprietà ottiche esclusivamente attraverso funzionalità base di OpenGL 1.2. L’implementazione del modello di Phong, basato sul calcolo del gradiente di opacità, e eseguito in tempo reale utilizzando i Register Combiner. I vincoli del real-time sono soddisfatti anche grazie alla applicazione di una tecnica di accelerazione multipass basata sulla copia rapida di informazioni dal framebuffer alla memoria di texture, offerta già dalla versione 1.1 di OpenGL

Extension of the shelf-life of fresh pasta using chickpea flour fermented with selected lactic acid bacteria

Fresh pasta is subjected to rapid spoilage, mainly due to the metabolic activity of bacteria, yeasts, and especially molds, which negatively affect the sensorial characteristics and the safety of the product. In this work, chickpea flour was fermented with selected lactic acid bacteria, characterized in terms of the antifungal activity, and used to fortify fresh semolina pasta. Pasta was characterized and subjected to a long period of storage after being artificially inoculated with Penicillium roqueforti. Conventional fresh semolina pasta, produced with or without calcium propionate addition, was used as a reference. The water/salt-soluble extract from chickpea sourdough exhibited antifungal activity towards a large spectrum of molds. Its purification led to the identification of ten potentially active peptides. Besides the high content of dietary fibers (4.37%) and proteins (11.20%), nutritional improvements, such as the decrease of the antinutritional factors concentration and the starch hydrolysis index (25% lower than the control) and the increase of the protein digestibility (36% higher than the control), were achieved in fresh pasta fortified with the chickpea sourdough. Inhibition of the indicator mold growth during a 40-day storage period was more effective than in pasta added to calcium propionate

Extension of the Shelf-Life of Fresh Pasta Using Chickpea Flour Fermented with Selected Lactic Acid Bacteria

Fresh pasta is subjected to rapid spoilage, mainly due to the metabolic activity of bacteria, yeasts, and especially molds, which negatively affect the sensorial characteristics and the safety of the product. In this work, chickpea flour was fermented with selected lactic acid bacteria, characterized in terms of the antifungal activity, and used to fortify fresh semolina pasta. Pasta was characterized and subjected to a long period of storage after being artificially inoculated with Penicillium roqueforti. Conventional fresh semolina pasta, produced with or without calcium propionate addition, was used as a reference. The water/salt-soluble extract from chickpea sourdough exhibited antifungal activity towards a large spectrum of molds. Its purification led to the identification of ten potentially active peptides. Besides the high content of dietary fibers (4.37%) and proteins (11.20%), nutritional improvements, such as the decrease of the antinutritional factors concentration and the starch hydrolysis index (25% lower than the control) and the increase of the protein digestibility (36% higher than the control), were achieved in fresh pasta fortified with the chickpea sourdough. Inhibition of the indicator mold growth during a 40-day storage period was more effective than in pasta added to calcium propionate

Different Flour Microbial Communities Drive to Sourdoughs Characterized by Diverse Bacterial Strains and Free Amino Acid Profiles

This work aimed to investigate whether different microbial assemblies in flour may influence the microbiological and biochemical characteristics of traditional sourdough. To reach this purpose, members of lactic acid bacteria, enterobacteria, and yeasts were isolated from durum wheat flour. Secondly, the isolated microorganisms (Pediococcus pentosaceus, Saccharomyces cerevisiae, Pantoea agglomerans, and Escherichia hermannii) were inoculated in doughs prepared with irradiated flour (gamma rays at 10 kGy), so that eight different microbial assemblies were obtained. Two non-inoculated controls were prepared, one of which (C-IF) using irradiated flour and the other (C) using non-irradiated flour. As shown by plate counts, irradiation of flour caused total inactivation of yeasts and a decrease of all the other microbial populations. However, acidification occurred also in the dough C-IF, due to metabolic activity of P. pentosaceus that had survived irradiation. After six fermentations, P. pentosaceus was the dominant lactic acid bacterium species in all the sourdoughs produced with irradiated flour (IF). Yet, IF-based sourdoughs broadly differed from each other in terms of strains of P. pentosaceus, probably due to the different microorganisms initially inoculated. Quantitative and qualitative differences of free amino acids concentration were found among the sourdoughs, possibly because of different microbial communities. In addition, as shown by culture-independent analysis (16S metagenetics), irradiation of flour lowered and modified microbial diversity of sourdough ecosystem

Un sistema multiprocessore per la simulazione della chirurgia sull'osso temporale

Nel presente articolo si presenta un simulatore per l’addestramento alla chirurgia dell’osso temporale. Il sistema si basa su modelli volumetrici direttamente derivati da dati 3D di TAC e MR. Il ritorno di sensazioni in tempo reale viene fornito all’utente per mezzo di tecniche di rendering volumetrico e di modellazione di sensazioni aptiche. I vincoli nelle prestazioni imposti dal sistema percettivo umano sono soddisfatti sfruttando il parallelismo attraverso il disaccoppiamento della simulazione su una piattaforma di PC multi-processore. In quest’articolo, vengono descritti in dettaglio i componenti del sistema e lo stato attuale dell’integrazione dei medesimi

Microbial cell-free extracts as sources of enzyme activities to be used for enhancement flavor development of ewe milk cheese

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Autism spectrum disorders and intestinal microbiota

Through extensive microbial-mammalian co-metabolism, the intestinal microbiota have evolved to exert a marked influence on health and disease via gut-brain-microbiota interactions. In this addendum, we summarize the findings of our recent study on the fecal microbiota and metabolomes of children with pervasive developmental disorder–not otherwise specified (PDD-NOS) or autism (AD) compared with healthy children (HC). Children with PDD-NOS or AD have altered fecal microbiota and metabolomes (including neurotransmitter molecules). We hypothesize that the degree of microbial alteration correlates with the severity of the disease since fecal microbiota and metabolomes alterations were higher in children with PDD-NOS and, especially, AD compared to HC. Our study indicates that the levels of free amino acids (FAA) and volatile organic compounds (VOC) differ in AD subjects compared to children with PDD-NOS, who are more similar to HC. Finally, we propose a new perspective on the implications for the interaction between intestinal microbiota and AD

Mobile graphics: SIGGRAPH Asia 2017 course

Peer ReviewedPostprint (published version

Sourdough fermentation of whole and sprouted lentil flours: In situ formation of dextran and effects on the nutritional, texture and sensory characteristics of white bread

Exopolysaccharides produced in situ by lactic acid bacteria during sourdough fermentation are recognized as bread texture improvers. In this study, the suitability of whole and sprouted lentil flours, added with 25% on flour weight sucrose for dextran formation by selected strains during sourdough fermentation, was evaluated. The dextran synthesized in situ by Weissella confusa SLA4 was 9.2 and 9.7% w/w flour weight in lentil and sprouted lentil sourdoughs, respectively. Wheat bread supplemented with 30% w/w sourdough showed increased specific volume and decreased crumb hardness and staling rate, compared to the control wheat bread. Incorporation of sourdoughs improved the nutritional value of wheat bread, leading to increased total and soluble fibers content, and the aroma profile. The integrated biotechnological approach, based on sourdough fermentation and germination, is a potential clean-label strategy to obtain high-fibers content foods with tailored texture, and it can further enhance the use of legumes in novel foods.Peer reviewe