Lactobacillus casei, dominant species in naturally fermented Sicilian green olives

This study investigated the phenotypic and genotypic characteristics of lactic acid bacteria in naturally fermented green olives, collected from different areas of Sicily. Both classical biochemical tests and PCR/Restriction Fragments Length Polymorphism (RFLP) of 16S rDNA were used to characterize the isolates. The identity of the isolates was obtained by the partial sequencing analysis of the 16S rDNA. The BioMerieux software assigned the 13 heterofermentative strains to the Lactobacillus brevis species; 24 homofermentative strains were classified as Lactobacillus casei and the remaining 11 homofermentative lactobacilli were identified as Lactobacillus plantarum. The rapid ID 32 STREP test identified coccal-shaped strains as Enterococcus faecium species. The PCR/RFLP analysis showed a remarkable bacterial heterogeneity within the isolates. The 16S rDNA partial sequencing did not confirm biochemical identification, revealing a strong dominance of isolates belonging to the L. casei species. It is noteworthy that this species has never been reported as dominant species in fermented vegetables.A combination of molecular and biochemical analysis allowed the identification of species involved in natural food fermentations.     

Pseudoneglect and embryonic light stimulation in the avian brain.

A bias to allocate attention to the left hemispace, similar to the well-known pseudoneglect phenomenon shown by humans, has been recently reported in domestic chicks and other species of birds. Asymmetrical light exposure of the embryo of the domestic chick in a critical period before hatching is known to be responsible for a structural asymmetry in the visual ascending projections of the thalamofugal pathway and for lateralization of some visual behaviors. Thus the animal model provided by the chick makes possible investigation of the prenatal factors that may influence asymmetry in spatial attention. Here chicks coming from eggs exposed to light (light incubated, Li-chicks) and chicks incubated in darkness (dark incubated, Di-chicks) were tested in a task in which they were required to explore an area in front of them and to sample grains of food. The results showed that Li-chicks attended more to target stimuli located in the left hemispace, whereas no asymmetry was shown by Di-chicks. When grains of food were presented with small novel pebbles as distractors, both Li- and Di-chicks tended to allocate attention toward the left hemispace. When, however, chicks were tested after familiarization with pebbles, no bias was shown by either Li- and Di-chicks. Hence it seems that cerebral lateralization associated with right hemispheric involvement in response to novelty, interacts with the modulatory effect of asymmetric embryonic light stimulation on preferential allocation of spatial attention in the left hemispace (right hemisphere) and right eye (left hemisphere) control of visual discrimination during feeding. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sequential cation exchange in nanocrystals: preservation of crystal phase and formation of metastable phases

We demonstrate that it is possible to convert CdSe nanocrystals of a given size, shape (either spherical or rod shaped), and crystal structure (either hexagonal wurtzite, i.e., hexagonal close packed (hcp), or cubic sphalerite, i.e., face-centered cubic (fcc)), into ZnSe nanocrystals that preserve all these characteristics of the starting particles (i.e., size, shape, and crystal structure), via a sequence of two cation exchange reactions, namely, Cd(2+) ?Cu(+) ?Zn(2+). When starting from hexagonal wurtzite CdSe nanocrystals, the exchange of Cd(2+) with Cu(+) yields Cu(2)Se nanocrystals in a metastable hexagonal phase, of which we could follow the transformation to the more stable fcc phase for a single nanorod, under the electron microscope. Remarkably, these metastable hcp Cu(2)Se nanocrystals can be converted in solution into ZnSe nanocrystals, which yields ZnSe nanocrystals in a pure hcp phase.     

Occurrence of Listeria monocytogenes in green table olives

Microbiological safety of green table olives from different cultivars, prepared by both the Spanish-style and biological methods and fermented with starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus pentosus), was investigated. The fermentation process was monitored by measuring pH values, titratable acidities, and growth of lactic acid bacteria over time. During fermentation, lactic acid bacteria and yeasts were major microbial populations. Microbiological safety was evaluated by analysis for Listeria monocytogenes with the use of an enrichment method during storage (from 55 days to 18 months). Results demonstrated that L. monocytogenes can survive and grow in green table olives. L. monocytogenes was found in one of the commercial (thermally treated) samples analyzed and in all samples older than 2 months, irrespective of olive cultivar, lactic acid bacteria starter used, pH and titratable acidity of brine samples, or treatment applied.     

Physicochemical, Microbiological, and Sensory Evaluation of Minimally Processed Tarocco Clone Oranges Packaged with 3 Different Permeability Films

ABSTRACT: Fruits of 3 Tarocco clones ('Gallo', 'Arcimusa', and 'Scirè') were sliced, packaged with different permeability films, and stored at 4°C for 14 to 15 d to find the best clone for processing and the most suitable packaging conditions to extend the shelf life of these products. Physicochemical parameters of Tarocco oranges slices, packaged with 3 films of different permeability, did not show marked decay phenomena during the storage days. Only a reduction in the ascorbic acid content was observed in almost all the examined clones, especially in products packaged with the most O₂ permeable films. Concerning microbiological contamination, all clones, packaged with the 3 films, showed, until the 12th storage day, a lower number of colony forming units (CFU)/g (≤ 3.6 × 10⁷ CFU/g) for mesophilic viable counts than the 2 microbiological criteria generally used for fresh-cut fruit and vegetables (10⁸ CFU/g for mesophilic viable counts). In fact, for these products it is possible to expect a shelf life longer than 12 to 13 d. Regarding sensory results, it was observed that the minimally processed Tarocco clone slices packaged with the most permeable to O₂ film were the most appreciated.     

Sulphadimethoxine and Azolla filiculoides Lam.: a model for drug remediation

Plants can be an interesting tool for in situ remediation of drug contaminated waters. In a laboratory model Azolla filiculoides Lam., an aquatic fern known to absorb pollutants, has been exposed to an environmental persistent antibiotic commonly used in intensive farming, sulphadimethoxine (S), to test its bioremediation capability. In a 5 week experiment, plants were cultivated outdoor at four drug concentrations (50, 150, 300 and 450 mg l(-1)) in N-free mineral medium. Drug affects growth rate (as biomass yield per week), N2-fixation, heterocyst frequency, but plants are able to survive. Notwithstanding, at all concentrations tested drug was actively removed from the medium and the accumulation in the biomass is in order of magnitude up to mg g(-1) plant dry weight (1000 ppm). Drug uptake and degradation rates increase with S concentrations in the culture medium. The efficacy of the model was very high. These results demonstrated that Azolla can be taken into consideration as a tool for sulphonamides environmental monitoring and decontamination.     

Structure and optical properties of silica-supported Ag-Au nanoparticles

Bimetallic Ag-Au nanoparticles are synthesized by sequential deposition of Au and Ag on amorphous silica by Radio Frequency (RF)-sputtering under mild conditions. Specimens are thoroughly characterized by a multi-technique approach, aimed at investigating the system properties as a function of the Ag/Au content, as well as the evolution induced by ex-situ annealing under inert (N2) or reducing (4% H2/N2) atmospheres. The obtained results demonstrate the possibility to obtain Ag-Au alloyed nanoparticles with controllable size, shape, structure, and dispersion under mild conditions, so that the optical properties can be finely tuned as a function of the synthesis and thermal treatment conditions.     

Development of novel peptidomimetics containing a vinyl sulfone moiety as proteasome inhibitors

Proteasome inhibition is a topic of great interest in anticancer research. The proteolytic activity of this multicatalytic complex relies on three subunits, β1, β2 and β5, containing a caspase-like, a trypsin-like and a chymotrypsin-like active site, respectively. Several studies have demonstrated that, of the three activities, the chymotrypsin-like activity was the most necessary for cell viability and protein processing. Thus, most efforts towards the development of proteasome inhibitors have focused on the selective inhibition of the β5 subunit active site. Herein, we report the design and synthesis of a series of conformationally constrained tripeptidyl vinyl sulfones were determined to be good inhibitors of the chymotrypsin-like activity of proteasome, with K(I) values in the sub-micromolar to micromolar range. These compounds were also tested against bovine pancreatic α-chymotrypsin and human cathepsin B and L, revealing a good selectivity for the target enzyme over these related enzymes.     

A systematic study on the effects of doping agents on polypyrrole coating of fabrics

Polypyrrole is widely used as coating to produce electrically conductive textiles. Counter‐ions (i.e. doping agents) were embedded in polypyrrole to improve electrical conductivity. Good electrical performances are required for several applications, such as microwave attenuation/electro‐magnetic interference shielding, heat generation, electro‐static discharge protection, sensing, and energy storage. In this work, a systematic study was carried out on the effects of doping agents in coating cotton fabrics with a thin polypyrrole layer. A total of 11 compounds were selected and compared as counter‐ions. The electrical performances of the coated fabrics were assessed with measures of electrical conductivity. Moreover, evenness and morphology of the resulting polypyrrole layer were discussed. As the final result, the best performances in terms of electrical conductivity (i.e. low surface resistivity) were measured using on dicyclohexyl sulfosuccinate, 2,6‐naphthalenedisulfonate or 1,5‐naphthalenedisulfonate as doping agents. The weight increases after polypyrrole deposition on the fabrics were greater than 15% and polypyrrole deposited on the fibers as a uniform film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42831.     

Survival of Lactobacillus rhamnosus strains inoculated in cheese matrix during simulated human digestion

Survival of probiotic bacteria during transit through the gastrointestinal (GI) tract is influenced by a number of environmental variables including stomach acidity, bile salts, digestive enzymes and food matrix. This study assessed survival of seven selected Lactobacillus rhamnosus strains delivered within a model cheese system to the human upper GI tract using a dynamic gastric model (DGM). Good survival rates for all tested strains were recorded during both simulated gastric and duodenal digestion. Strains H12, H25 and N24 demonstrated higher survival capacities during gastric digestion than L. rhamnosus GG strain used as control, with H12 and N24 continuing to grow during duodenal digestion. Strains L. rhamnosus F17, N24 and R61 showed adhesion properties to both HT-29 and Caco-2 cells. The ability to attach to the cheese matrix during digestion was confirmed by scanning electron microscopy, also indicating production of extracellular polysaccharides as a response to acid stress.