Widely distributed lysogeny in probiotic lactobacilli represents a potentially high risk for the fermentative dairy industry

Prophages account for most of the genetic diversity among strains of a given bacterial species, and represent a latent source for the generation of virulent phages. In this work, a set of 30 commercial, collection and dairy-isolated Lactobacillus casei group strains were used. A species-specific PCR assay allowed a reclassification, mainly of strains previously considered Lactobacillus casei, into either Lactobacillus paracasei or Lactobacillus rhamnosus. All the strains were induced with mitomycin C, allowing direct recovering of phage DNA in 25 cases, which corroborates the widely occurrence of lysogeny on Lactobacillus genomes, including probiotic strains of Lactobacillus casei group. Ten out of 11 commercial strains studied contained prophages, evidencing the potential risks of their use at industrial scale. Strains were also induced by treatment with different concentrations of hydrogen peroxide but, however, this agent was not able to evidence a prophage release for any of the strains tested. According to a RAPD-PCR fingerprinting with M13, 1254 and G1 primers, most of the commercial strains presented a high degree of homology and, regarding BglII- and BamHI-restriction profiles of phage DNA, six of them harboured the same prophage. Surprisingly, both Lactobacillus paracasei ATCC 27092 and Lactobacillus paracasei ATCC 27139 shared a second prophage with both an INLAIN collection and a commercial Lactobacillus paracasei strains, whereas two collection strains shared a third one. On the other hand, mitomycin C-inducible prophages were detected only on about a half of the strains isolated from dairy products, which had (with only one exception) from moderate to high correlation coefficients according to RAPD-PCR fingerprinting. After induction, supernatants were filtered and tested against nine Lactobacillus strains of the set sensitive to previously assayed virulent phages, allowing isolation of two new virulent phages: ф iLp1308 and ф iLp84. Both phages were able to lyse all but one strains sensitive to previously assayed phage MLC-A.     

Process simulation of a hybrid SOFC/mGT and enriched air/steam fluidized bed gasifier power plant

The aim of this work is to experimentally and numerically analyze the performance of a integrated power plant composed by a steam oxygen fluidized bed biomass gasifier fed by woods, a Solid Oxide Fuel Cell (SOFC) and a micro Gas Turbine (mGT). The numerical analysis is carried out by using ChemCAD software. In particular, SOFC and gasifier were modeled using proper developed Fortran subroutines interfaced to the basic software. The adopted SOFC model was already validated by the authors in previous works, while the gasifier model was here developed and validated by means of experimental activities carried out by using a bench scale gasifier. Different compounds (Benzene, Toluene, Naphthalene, Phenols) were chosen to analyze the tar evolution in the gaseous stream during the gasification process. Hot gas cleaning (based on catalytic ceramic filter candles inserted in the freeboard of the gasifier – UNIQUE concept) was adopted to remove tar and particulates from the fuel hot gas stream. Different moisture contents in the range between 10 and 30% (i.e. in a deviation of 10% around the usual wood moisture content of 20%) were numerically simulated as well as the degree of purity of the oxygen utilized in the power plant (between 25% and 95%, the rest being N₂). The power requirement for pure oxygen production leads to a reduction of the electrical efficiency of the whole power plant. For this reason, a sensitivity analysis was conducted to find the optimal operation conditions in order to maximise the syngas (H₂, CO) content in the produced gas, while maintaining a high overall electrical efficiency.     

Distributed measurement systems

In this paper the technologies that permit the development of distributed measurement systems over the internet are discussed. The different concepts of virtual instrumentation are summarized. Two different approaches to measurement system development are compared — the first is based on the commercially available environment , and the second, widely used in the research field, is based on the object-oriented programming.     

Histochemical characterization of the sialic acid residues in mouse colon mucins

The mucins of colonic murine mucus are highly O‐glycosilated sulfosialoglycoproteins. We have characterized the sialylation pattern of oligosaccharide chains of colonic murine mucins by conventional histochemical methods and by lectin histochemistry combined with chemical pretreatments and sialidase digestion. Oligosaccharide chains are strongly sulphated, with an increase of sulfation from the proximal toward the distal colon and a decrease of sialic acid expression and acetylation toward the distal colon. In the goblet cells of proximal colon, sialic acid bound α2,3 to Galβ1,3GalNAc subterminal dimers is diacetylated at C7,C8;C7,C9;C8,C9 or triacetylated at C7,8,9. In the distal colon, sialic acid‐linked α2,3 to Galβ1,3GalNAc subterminal dimers shows reduced O‐acetylation at C7 and/or C8, while acetyl substituents at C9 and at C4 are almost absent. Sialic acid is involved in different essential physiological functions; thus, alterations of its expression and acetylation in oligosaccharide chains of intestinal mucins are generally associated with diseases, such as ulcerative colitis and cancer. Mice may represent a suitable animal model to study alterations of oligosaccharidic chains in colonic mucins and lectin histochemistry combined with chemical pretreatments, and enzyme digestion may be a valuable tool for this study. Our present work may represent a landmark for further lectin histochemical studies to evaluate alterations of mouse colon mucins under different physiological, pathological, or experimental conditions, with possible translational value in humans. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Finite memory non-linear model of a S/H-ADC device

A new model has been proposed for the characterisation of the non-linear dynamic effects of a S/H-ADC device and a new mathematical approach has been introduced to describe its non-ideal dynamic behaviour. The measurement procedure to deduce the parameters of the proposed model is given together with the experimental results on a commercial device.     

A Framework for Using Web Services to Enhance QoS for Content Delivery

An integrated approach to quality of service for content delivery using Web services includes quality definitions, user contracts, and fault monitoring.     

A scaled 0.25-μm bipolar technology using full e-beamlithography

The full leverage offered by electron-beam lithography has been exploited in a scaled 0.25-μm double polysilicon bipolar technology. Devices and circuits were fabricated using e-beam lithography for all mask levels with level-to-level overlays tighter than 0.06 μm. Ion implantation was used to form a sub-100-nm intrinsic base profile, and a novel in-situ doped polysilicon emitter process was used to minimize narrow emitter effects. Transistors with 0.25-μm emitter width have current gains above 80 and cutoff frequencies as high as 40 GHz. A record ECL gate delay of 20.8 ps at 4.82 mW has been measured together with a minimum power-delay product of 47 fJ (42.1 ps at 1.12 mW). These results demonstrate the feasibility and resultant performance leverage of aggressive scaling of conventional bipolar technologies     

Genotyping of fig (Ficus carica L) via RAPD markers

The genetic diversity among 15 fig accessions (Ficus carica L), belonging to 9 renowned cultivars of the Calabrian fig collection, and 24 unidentified genotypes of figs also located in the Calabrian region of Southern Italy, was investigated by random amplified polymorphic DNA (RAPD) analysis. The genetic similarity values were calculated for the 39 samples, and a dendrogram was elaborated by cluster analysis according to the UPGMA algorithm. The generated DNA fragments grouped the samples into two main clusters of RAPD profiles. Most of the 24 unknown samples, coming from the Luzzi area, formed a unique cluster with high degree of genetic similarity. This indicates that it is possible to distinguish, at DNA level, the fig trees with an already well‐known potential to produce figs suitable for the drying process and possibly to specify cultivars with suitable features for industrial transformation. Copyright © 2005 Society of Chemical Industry     

Radioactive Marker Measurements in Heterogeneous Reservoirs: Numerical Study

A numerical study is performed to simulate the vertical deformation of a depth interval representing a marker spacing (10.5 m) located in a deep heterogeneous sedimentary reservoir. Realistic lithostratigraphic sequences typical of the Northern Adriatic basin are used. A number of scenarios are addressed consistent with the available data. In particular two basic geologic scenarios at the marker scale are simulated, one where sands prevail within the marker spacing (SD), and another where thin sandy and clayey layers alternate (CL). The sensitivity of the marker response is investigated in relation to clay and sand permeability and compressibility contrast, Biot’s coefficient, and respective position of monitoring and fluid pumping wells. The modeling results show that rock may indeed expand above and below depleted layers. Depending on the marker position the expansion may partially offset the compaction, especially in the CL scenario with a very low permeable clay. To obtain a representative field compaction the markers should span a depth interval made mostly by sand and entirely depleted, and should be installed in a test hole far from producing wells. Compressibility contrast and the Biot coefficient play a secondary role. Very critical measurements are provided by two markers which incorporate a thin (≈1 m) depleted level overlain and underlain by almost impermeable clay layers.