PubMed Health⌕ Search

Biomedical subjects

P Buzzini

Publications and source records attributed to P Buzzini.

18 recordsLinked to original sources

Nicephor[e]: a web-based solution for teaching forensic and scientific photography.

Nicephor[e] is a project funded by "Swiss Virtual Campus" and aims at creating a distant or mixed web-based learning system in forensic and scientific photography and microscopy. The practical goal is to organize series of on-line modular courses corresponding to the educational requirements of undergraduate academic programs. Additionally, this program could be used in the context of continuing educational programs. The architecture of the project is designed to guarantee a high level of knowledge in forensic and scientific photographic techniques, and to have an easy content production and the ability to create a number of different courses sharing the same content. The e-learning system Nicephor[e] consists of three different parts. The first one is a repository of learning objects that gathers all theoretical subject matter of the project such as texts, animations, images, and films. This repository is a web content management system (Typo3) that permits creating, publishing, and administrating dynamic content via a web browser as well as storing it into a database. The flexibility of the system's architecture allows for an easy updating of the content to follow the development of photographic technology. The instructor of a course can decide which modular contents need to be included in the course, and in which order they will be accessed by students. All the modular courses are developed in a learning management system (WebCT or Moodle) that can deal with complex learning scenarios, content distribution, students, tests, and interaction with instructor. Each course has its own learning scenario based on the goals of the course and the student's profile. The content of each course is taken from the content management system. It is then structured in the learning management system according to the pedagogical goals defined by the instructor. The modular courses are created in a highly interactive setting and offer autoevaluating tests to the students. The last part of the system is a digital assets management system (Extensis Portfolio). The practical portion of each course is to produce images of different marks or objects. The collection of all this material produced, indexed by the students and corrected by the instructor is essential to the development of a knowledge base of photographic techniques applied to a specific forensic subject. It represents also an extensible collection of different marks from known sources obtained under various conditions. It allows to reuse these images for creating image-based case files.

Computer-Assisted Instruction↗

Analysis of condensed and hydrolysable tannins from commercial plant extracts.

High performance liquid chromatography (HPLC)/DAD and MS qualitative and quantitative analyses of polyphenols, hydrolysable and condensed tannins from Pinus maritima L. and tannic acid (TA) extracts were performed using normal and reverse phase. Normal-phase HPLC was more suitable for pine bark (PBE) and tannic acid extracts analysis. The chromatographic profile revealed that P. maritima L. extract was mainly composed by polymeric flavanols (containing from two to seven units) and tannic acid (characterized by a mixture of glucose gallates containing from three to seven units of gallic acid). Concerning their antimycotic properties, P. maritima L. extract exhibited a broad activity towards yeast strains of the genera Candida, Cryptococcus, Filobasidiella, Issatchenkia, Saccharomyces: MICs from 200 to 4000 microg/ml (corresponding to 140-2800 microg/ml of active polyphenols) were determined. Conversely, no activity of tannic acid was observed over the same target microorganisms. Taken into consideration the above results of HPLC analysis and on the basis of the current literature, we may conclude that only 70.2% of polyphenols (recognized as condensed tannins) occurring in P. maritima L. extract can be apparently considered responsible for its antimycotic activity.

Antifungal Agents↗

A comparison of efficiency of manual and automatic fibres search with the Maxcan fibre finder.

The aim of this work was to study the efficiency of automatic fibre searching with the Maxcan fibre finder (Cox Analytical Systems, Sweden) in comparison to manual searching. The influence of some parameters (color, thickness, background noise) on the results of a fibre search was considered. Eighteen experimental tapes with different target fibres and different background noises were prepared in the laboratory. Searching of fibres was performed manually and with the Maxcan fibre finder by different operators from four European laboratories. Two laboratories have the Maxcan fibre finder system and the two instruments were used and compared in this study. The results show that searching with the Maxcan is generally as efficient as manual searching, except for very pale or very dark fibres. Note that the tapes used for these experiments were prepared in laboratory, and are not completely representative of the tape that could be obtained in real cases. To generalize the results obtained, further research on real case samples would be necessary.

Journal Article↗

Raman spectroscopy and the forensic analysis of black/grey and blue cotton fibres Part 1: investigation of the effects of varying laser wavelength.

Raman spectroscopy was investigated to determine the optimal conditions, mainly laser wavelength/s, for the analysis of the commonly encountered black/grey and blue cotton fibres dyed with reactive dyes. In this first part, a single blue cotton fibre, its three dye components, and an undyed cotton fibre were analysed with five different laser wavelengths from two different Raman microprobe spectrometers. The quality of the spectra, fibre degradation and speed of acquisition were used to determine that, under the conditions used, the 785 and 830 nm lasers gave superior results. The 632.8 nm laser wavelengths provided good results with little acquisition time and no spectral degradation. Results indicate that, at least, the major dye component could be identified using Raman spectroscopy.

Journal Article↗

In vitro antimycotic activity of some plant extracts towards yeast and yeast-like strains.

As part of screening aimed at the selection of novel antimycotic compounds of vegetable origin, leaf extracts of Camellia sinensis L., Cupressus sempervirens L. and Pistacia lentiscus L. and the seed extract of Glycine soja Sieb. et Zucc. were tested against yeast and yeast-like species implicated in human mycoses. Of the extracts only those of C. sinensis (obtained from a commercial preparation of green tea) exhibited broad activity towards Candida glabrata, Clavispora lusitatiae, Cryptococcus laurentii, Filobasidiella neoformans, Issatchenkia orientalis, Saccharomyces cerevisiae and Prototheca wickerhamii strains. MICs ranging from 300 to 4800 microg extract/mL (corresponding to 130-2010 microg/mL total polyphenols) were observed. Concentrations of the C. sinensis extract over 25 000 microg/mL caused a rapid decrease of viable cells of Fil. neoformans and its activity was dose-dependent. Tests carried out using the pure polyphenols present in C. sinensis extract composition, showed that only epicatechin-3-O-gallate (ECG) and epigallocatechin-3-O-gallate (EGCG) possess antimycotic activity.

Antifungal Agents↗

Use of RAPD and killer toxin sensitivity in Saccharomyces cerevisiae strain typing.

AIMS: Two different strain characterization techniques, random amplified polymorphic DNA (RAPD) and killer toxin sensitivity (KTS), were compared to assess their typing performance using a set of 30 certified Saccharomyces cerevisiae strains. METHODS AND RESULTS: A sequential random resampling procedure was employed to subdivide the 32 descriptors in eight sets, in order to compare the differential performances of the two techniques with diverse number of characters. Results showed that RAPD performs better than killer, although the complete differentiation of the strains under study could be obtained only by combining profiles from the two techniques. CONCLUSIONS: The combination of different typing techniques was useful when discriminating similar organisms. In such cases, the introduction of a second typing technique can be more advantageous than increasing the number of characters obtained with a single method. SIGNIFICANCE AND IMPACT OF THE STUDY: The distribution of among-strains pairwise distances and the relative performance of the two techniques has implications for the study of biodiversity, taxonomy and microbial ecology.

DNA, Fungal↗

First large-scale isolation of Prototheca zopfii from milk produced by dairy herds in Italy.

A total of 1045 milk samples collected from infected and non infected quarters of 269 cows were investigated. This study showed that 4.7% of samples possessed cells of Prototheca spp. (10(6)cells/ml). The presence of other pathogenic microorganisms was also monitored. Prototheca spp. isolates were classified on the basis of current taxonomic guidelines and identified as P. zopfii. Susceptibility tests carried out in vitro by using 25 antibiotic compounds revealed that the strains of P. zopfii. were susceptible only to nystatin and amphotericin B (58 and 33% of total strains, respectively). The present study represents the first large-scale investigation carried out in Italy on the isolation of this achlorophyllous yeast-like microalga in milk samples produced by dairy herds.

Amphotericin B↗

Assessment of discriminatory power of three different fingerprinting methods based on killer toxin sensitivity for the differentiation of Saccharomyces cerevisiae strains.

AIMS: A panel composed of 44 taxonomically certified strains of Saccharomyces cerevisiae of different origin was used to evaluate the discriminatory power of three different fingerprinting methods based on sensitivity towards 24 killer toxins. METHODS AND RESULTS: Binary data matrix (BDM), triplet data matrix (TDM) and numerical data matrix (NDM) were used as fingerprinting methods. NDM possessed the highest discriminatory power, assessed through the Simpson's, and Hunter and Gaston's indices for the measurement of diversity. The upper limits of fingerprinting ability expressed by the three above methods have been also discussed. CONCLUSIONS: NDM determined a significant increase of discriminatory power than the use of BDM or TDM, in terms of an effective amplification of their fingerprinting efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The NDM fingerprinting method could find application in control laboratories for the discrimination of yeast strains of industrial importance or covered by patent.

DNA Fingerprinting↗

Fingerprinting of yeasts at the strain level by differential sensitivity responses to a panel of selected killer toxins.

We used differential sensitivities to a panel of twenty-five cell-free crude killer toxins to fingerprint forty-four Saccharomyces cerevisiae strains of different origin and all taxonomically certified by nDNA-nDNA reassociation. Cluster analysis of numerical data obtained by different growth inhibition areas observed in Petri dishes allowed the complete and reproducible discrimination of all S. cerevisiae strains.

Antibiosis↗

Extracellular enzymatic activity profiles in yeast and yeast-like strains isolated from tropical environments.

AIMS: The objective of this study was to investigate the extracellular enzymatic activity (EEA) profile of yeasts isolated from tropical environments of the Brazilian rain forest. This screening survey could constitute the first approach in selecting yeast strains of environmental origin potentially exploitable as enzyme producers. METHODS AND RESULTS: In this study, 348 yeast (193 ascomycetes and 155 basidiomycetes) and 46 yeast-like strains (Aureobasidium pullulans) were screened for their EEA profile. The spread occurrence of extracellular amylases, esterases, lipases, proteases, pectinases and chitinases appeared to be a strain-related character. CONCLUSIONS: Yeasts isolated from tropical environments could represent a promising source of EEA. Selected strains showed maximum levels of EEA under acidic or neutral conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the potential for yeasts isolated from extreme environments as sources of industrially relevant enzymes for biotechnological purposes.

Ascomycota↗

Batch and fed-batch carotenoid production by Rhodotorula glutinis-Debaryomyces castellii co-cultures in corn syrup.

AIMS: Investigations on the production of red pigments by Rhodotorula glutinis on raw substrates of agro-industrial origin may be considered of interest because they represent the first approach to the utilization of these raw materials for biotechnological purposes. METHODS AND RESULTS: Rhodotorula glutinis DBVPG 3853 was batch and fed-batch co-cultured with Debaryomyces castellii DBVPG 3503 in a medium containing corn syrup as the sole carbon source. Fed-batch co-cultures gave a volumetric production of 8.2 mg total carotenoid l(-1), about 150% of that observed in batch co-cultures. The different carotenoid pigments (beta-carotene, torulene, torularhodin) were quantified. CONCLUSION: Oligosaccharides and dextrins of corn syrup could be used profitably for pigment production by R. glutinis DBVPG 3853-D. castellii DBVPG 3503 in co-culture. SIGNIFICANCE AND IMPACT OF THE STUDY: The above results suggest that the red yeasts belonging to the genus Rhodotorula may have industrial relevance as carotenoid producers.

Carotenoids↗

Large-scale screening of selected Candida maltosa, Debaryomyces hansenii and Pichia anomala killer toxin activity against pathogenic yeasts.

The killer activity of selected crude toxins produced by nine Candida maltosa, Debaryomyces hansenii and Pichia anomala strains was tested at 37 degrees C against 383 strains belonging to 19 pathogenic species of 10 genera (Candida, Clavispora, Cryptococcus, Filobasidiella, Issatchenkia, Kluyveromyces, Pichia, Saccharomyces, Stephanoascus and Trichosporon). The broad killer spectra exhibited by all crude toxins may lead to the development of new antimycotic agents against medically important yeasts.

Antifungal Agents↗

Discrimination between Candida albicans and other pathogenic species of the genus Candida by their differential sensitivities to toxins of a panel of killer yeasts.

The differential sensitivities to toxins produced by a short panel of four killer yeasts allowed discrimination between 91 strains of the yeast Candida albicans and 223 non-C. albicans Candida strains. One hundred percent of C. albicans isolates exhibited negative results to the toxin panel, while 100% of non-C. albicans cultures gave well-defined and reproducible positive results to at least one of the four killer toxins. Among C. albicans strains only 96 and 87% gave germ tube (GT)- and chlamydospore-positive results, respectively. In addition a few GT-false-positive strains were detected among non-C. albicans isolates. Susceptibility to the toxin panel is apparently expressed more consistently than either GT or chlamydospore production and may constitute a promising basis for a new simple and easy-to-use procedure for routine discrimination between the species C. albicans and other species of the genus Candida.

Candida↗

Differential growth inhibition as a tool to increase the discriminating power of killer toxin sensitivity in fingerprinting of yeasts.

A panel of 27 cell-free crude killer toxin preparations were used in fingerprinting 45 Saccharomyces cerevisiae and 11 Saccharomyces exiguus strains. The differential sensitivity to different mycocins was evaluated both as binary data matrix (presence-absence of killing effect), and by considering the growth inhibition areas (measured by agar diffusion well bioassay). The first approach gave an individual fingerprinting of 68% of sensitive strains, whereas the second gave a total and reproducible (P<0.01) discrimination of all tested strains.

Antibiosis↗

Utilisation of differential killer toxin sensitivity patterns for fingerprinting and clustering yeast strains belonging to different genera.

The differential killer sensitivity of 103 yeast cultures belonging to 12 species (genera Debaryomyces, Kluyveromyces, Saccharomyces, and Zygosaccharomyces), all previously taxonomically certified by nDNA-nDNA reassociation, against a given panel of 39 killer yeasts was used as a fingerprinting tool. All strains, with the only exception of eight cultures belonging to the species Zygosaccharomyces bailii, were characterised by a specific, individual sensitivity pattern (killer formula). Cluster analysis of binary sequences based on killer sensitivity of strains belonging to different genera is presented and discussed.

Cluster Analysis↗

Biodiversity of killer activity in yeasts isolated from the Brazilian rain forest.

The occurrence of killer activity against a panel composed of 22 industrially and (or) medically important yeasts was investigated in 438 yeast and yeast-like cultures belonging to 96 species, isolated from different environments of the Brazilian rain forest. Altogether, 26% of ascomycetes, 56% of basidiomycetes, and 42% of yeast-like cultures exhibited killer activity against at least one of the panel yeasts. More than 15 species never reported before as toxin producers were found, with Pseudozyma antarctica, Trichosporon asteroides, and Geotrichum klebahnii, showing the broader activity spectra. Plasmid curing did not cure the killer phenotypes of Candida maltosa, Debaryomyces hansenii, G. klebahnii, Tr. asteroides, Cryptococcus laurentii, and Ps. antarctica.

Ascomycota↗

A market study of green spray paints by Fourier transform infrared (FTIR) and Raman spectroscopy.

A market study of 40 different green spray paints was carried out using infrared (FTIR) and Raman spectroscopy. The infrared technique distinguished between the 12 main groups based on their binder and extender composition. After visual comparison of the spectra 22 subgroups were observed. Raman spectroscopy was also carried out on the 40 reference paints in order to determine the pigment content. Analyses were undertaken using two different excitation sources: Argon ion (514.5 nm) and Helium-Neon (632.8 nm). The first generated strong fluorescence for most of the samples and created eight groups. Using the red laser, 15 classes were observed. Finally, using an analytical sequence starting with infrared spectroscopy followed by Raman Helium-Neon and then by Raman Argon laser, most of the paints were differentiated. In this study infrared and Raman spectroscopy complemented each other. FTIR supplied information about the binder and some extenders, and Raman provided information on the main organic pigments present.

Journal Article↗