1,721,007 research outputs found
Characterization of Pseudomonas spp. Isolated from Foods
Full text linkPutative Pseudomonas spp. (102 isolates) from different foods were first characterised by API 20NE and then tested for some
enzymatic activities (lipase and lecithinase production, starch hydrolysis and proteolytic activity). However subsequent molecular tests
did not always confirm the results obtained, thus highlighting the limits of API 20NE. Instead RFLP ITS1 and the sequencing of 16S rRNA
gene grouped the isolates into 6 clusters: Pseudomonas fluorescens (cluster I), Pseudomonas fragi (cluster II and V) Pseudomonas
migulae (cluster III), Pseudomonas aeruginosa (cluster IV) and Pseudomonas chicorii (cluster VI). The pectinolytic activity was typical
of species isolated from vegetable products, especially Pseudomonas fluorescens. Instead Pseudomonas fragi, predominantly isolated
from meat was characterised by proteolytic and lipolytic activities
Development of PCR assay to identify Pseudomonas fluorescens and its biotype
No full textThe paper provides a simple protocol that uses the polymerase chain reaction to amplify a specific portion of the 16S gene, allowing the recognition of Pseudomonas fluorescens from other group I Pseudomonas. The amplified DNA patterns of 16S rRNA and ITS1, from the restriction fragment length polymorphisms VspI, HaeIII and TaqI digestion, produced band patterns that distinguished the biotypes of Ps. fluorescens. In addition to distinguishing the biotypes C and 3 we used a phenotypical method for levan production
ADVANCED MATERIALS: PREPARATION, STUDY AND OPTIMIZATION OF THIN FILM FOR OPTO-ELECTRONIC DEVICE
Full text linkThe term “optoelectronic devices” is by now used for devices in which both electrons and photons are essential for their operation, as a natural evolution from the definitions of electronic devices that involved only electrons and holes in their operation and of photonic devices that involved only photons in their operation. One of the new lighting technologies which emerged within the past two decades and has the potential of becoming more energy-efficient then the existing light sources, is the Solid State Lighting technology of Organic Light Emitting Diodes (OLEDs). In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting anode and metallic cathode. When an appropriate current is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). The first part of this PhD Thesis surveyed different aspect in OLED technology that are currently under debate. In particular chapter 2 is devoted to the study, preparation and optimization of thin films between the organic hole transport layer and the anode surface while chapter 3 deals with the synthesis of trifluorene compound, with methoxy substituents, as possible UV-blue emitter. The second part of this PhD work is dedicated to the synthesis and study of new materials with interesting emissive and second order NLO properties. In particular pyrene based chromophores are investigated in chapter 4, while chapter 5 deals with the synthesis of organic-inorganic perylene-POSS hybrids with enhanced emissive properties
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development of Genus/Species-Specific PCR Analysis for identification of Carnobacterium strains
No full textHeterofermentative lactic acid bacteria belonging to the genus Carnobacterium are currently divided into seven different species, C. piscicola, C. mobile, C. gallinarum, C. inhibens, C. divergens, C. funditum, and C. alterfunditum. 16S rDNA-targeted PCR assay was carried out for the identification of the genus Carnobacterium. In addition, type strains of all Carnobacterium species were analyzed by 16S–23S rDNA intergenic spacer analysis in comparison with type strains of phylogenetically related lactic acid bacteria. These methods enabled the identification and the discrimination among Carnobacterium species and the other phylogenetically related lactic acid bacteria. Likewise, analogous results were obtained by restriction analysis of amplified 16S rDNA performed with HaeIII and HinfI as
restriction enzymes
Carnobacterium spp. in seafood packaged in modified atmosphere
Full text linkThe composition of lactic acid population in five kinds of seafood (salmon,tuna, shrimps, swordfish and cuttlefish) packaged in two different modified atmospheres,MAP1 (80 O2/20 N2) and MAP2 (40 CO2/60 N2), at 4 °C for 6 days was investigated. The isolates were heterofermentative rods belonging to Carnobacterium, Lactobacillus, and
cocci of the Leuconostoc genus. The determination of phenotypical characters and a new polymerase chain reaction primer were used to distinguish Carnobacterium from Lactobacillus. The microorganisms found varied with the kind of seafood and the gas composition of the modified atmospheres: in MAP1, richer of oxygen than MAP2, Carnobacterium spp. represents the prevalent microbial group, especially in tuna, shrimps and swordfish, whereas MAP2 seems to favour Lactobacillus spp. Cocci, belonging to Leuconostoc spp., were dominant in salmon and cuttlefish independently of gas composition
Phenotypic and Genotypic Characterization of Enterococcus spp. of Different Origins
No full textSixty-four strains of Enterococcus spp. of different origin were identified using traditional phenotypic, biochemical and cultural tests, together with molecular tests. API 20 STREP tests identified the species at a preliminary level, only one strain remaining unidentified. Strains belonging to the genus Enterococcus were tested with genus-specific primers, while species-level identification was carried out with the 16S-23S rDNA intergenic region (ITS) and species-specific primers for E. faecium and E. faecalis. Those strains found to be negative with the species-specific primers were subjected to 16S rDNA partial sequencing
La gestione degli scambiatori di calore a piastre per il trattamento di latte e derivati
No full textScarsa manutenzione, formazione e addestramento inadeguati sono le cause più frequenti di accumuli inattesi di depositi di sporco e delle ridotte efficienze prestazionali di scambiatori di calore a piastr
Reclassification of Lactobacillus maltaromicus (Miller et al. 1974) DSM 20342T and DSM 20344 and Carnobacterium piscicola (Collins et al. 1987) DSM 20730T and DSM 20722 as Carnobacterium maltaromaticum comb. nov
No full textPhenotypic and genotypic characterizations of Lactobacillus maltaromicus strains DSM 20342T
and DSM 20344 provided evidence for the reclassification of this species in the genus Carnobacterium. Moreover, phenotypic and genotypic comparisons made between L. maltaromicus and Carnobacterium piscicola highlighted that these two species should be
considered synonyms. For these reasons, the species Carnobacterium maltaromaticum comb. nov.
(type strain DSM 20342T=ATCC 27865T=CCUG 30142T=CIP 103135T=JCM 1154T=LMG 6903T=NRRL B-14852T) is proposed to accommodate L. maltaromicus and C. piscicola
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