Determination of styrene content in Gorgonzola PDO cheese by headspace solid phase micro-extraction (HS-SPME) and gas-chromatography mass-spectrometry (GC-MS).

Control of the composition of products that are intended for use as packaging material is essential, particularly when these products come into direct contact with food. It is well known that plastics are not inert and that their residual monomers, starting substances, and additives are able to migrate into the food they contact. Among plastics, styrene is a common compound found in many plastic containers that can also be produced by the oxidation of Penicillium roqueforti used in gorgonzola Protected Denomination of Origin cheese manufacturing. Therefore, solid-phase microextraction combined with gas chromatography/mass spectrometry was applied in the present work to determine the styrene content in packaged and unpackaged gorgonzola cheese samples to understand styrene migration phenomena from plastic containers.

Investigation of fungal contamination in sheep and goat cheeses in southern Italy.

One hundred and twenty-two samples of cheeses made from goat and sheep milk and a mixture of the two types, produced in Southern Italy by industrial establishments or artisans, were analysed for the detection of fungal contamination and the presence of potentially toxigenic moulds. Only organoleptically acceptable cheeses without evident fungal contamination were studied. Among these, 40 were unripened, 30 medium and 52 long ripened cheeses. Moulds were found in 54 of the 122 analysed samples (44.3%). The most contaminated cheeses were the medium and long ripened ones (46.3% and 35.2%), and the industrial cheeses (59.1%). The artisan cheeses were the least contaminated (26.8%). Among the cheeses that tested positive, Penicillium species were the most frequently isolated (72.9%), followed by Geotrichum spp. (7.3%), Aspergillus spp. (4.2%) and Mucor spp. (4.2%). The potentially toxigenic species within the genera Penicillium, Aspergillus and Fusarium were mainly detected in sheep cheeses.

Cloning and characterization of murine EDF-1.

Murine endothelial differentiation-related factor (mEDF-1) encodes a basic intracellular protein of 148 amino acids which is highly homologous to the human and rat polypeptides. mEDF-1 is expressed in most murine tissues tested and is evolutionary conserved. mEDF-1 expression is modulated in mouse development, since its expression is high early in development and decreases thereafter. Because EDF-1 has been isolated as a gene differentially expressed by exposure of endothelial cells to the Tat protein of HIV, we evaluated mEDF-1 expression in different cell lines derived from tumors which spontaneously develop in Tat transgenic mice. Cells isolated from adenocarcinomas and leiomyosarcomas express very high amounts of EDF-1, independently from their capability to secrete Tat. Tat transgenic mice also develop skin lesions which closely resemble human Kaposi's sarcoma. Since Kaposi spindle cells, which are the proliferative component of the sarcoma, differentiate from an endothelial precursor, it is noteworthy that spindle cells derived from Kaposi-like lesions of the Tat transgenic mice downregulate EDF-1 when compared to microvascular endothelial cells isolated from the same tissue.

Methods and approaches in the analysis of gene expression data.

The application of high-density DNA array technology to monitor gene transcription has been responsible for a real paradigm shift in biology. The majority of research groups now have the ability to measure the expression of a significant proportion of the human genome in a single experiment, resulting in an unprecedented volume of data being made available to the scientific community. As a consequence of this, the storage, analysis and interpretation of this information present a major challenge. In the field of immunology the analysis of gene expression profiles has opened new areas of investigation. The study of cellular responses has revealed that cells respond to an activation signal with waves of co-ordinated gene expression profiles and that the components of these responses are the key to understanding the specific mechanisms which lead to phenotypic differentiation. The discovery of 'cell type specific' gene expression signatures have also helped the interpretation of the mechanisms leading to disease progression. Here we review the principles behind the most commonly used data analysis methods and discuss the approaches that have been employed in immunological research.

Roquefortine C occurrence in blue cheese.

Several strains of Penicillium are used for the production of mold-ripened cheeses, and some of them are able to produce mycotoxins. The aims of the research were the determination of roquefortine C and PR toxin in domestic and imported blue cheeses, the identification of the penicillia used as starter, and the investigation of their capacity for producing toxins in culture media. Roquefortine C was always found in the cheeses at levels ranging from 0.05 to 1.47 mg/kg, whereas the PR toxin was never found. The identification of the fungal strains present in the domestic cheeses included Penicillium glabrum, Penicillium roqueforti, and Penicillium cyclopium in the Gorgonzola "dolce" and Penicillium roqueforti in the Gorgonzola "naturale"; in one case, the presence of Penicillium crustosum was observed. The strains isolated from the foreign cheeses belonged to P. roqueforti. The strains were able to produce between 0.18 and 8.44 mg/liter of roquefortine in yeast extract sucrose medium and between 0.06 and 3.08 mg/liter and less than 0.05 mg/liter when inoculated in milk at 20 degrees C for 14 days and 4 degrees C for 24 days, respectively. Linear relations between production of roquefortine in culture media and cheeses did not emerge. PR toxin ranged from less than 0.05 to 60.30 mg/liter in yeast extract sucrose medium and was produced in milk at 20 degrees C from only one strain. The low levels and the relatively low toxicity of roquefortine make the consumption of blue cheese safe for the consumer.

EDF-1, a novel gene product down-regulated in human endothelial cell differentiation.

Endothelial cell differentiation is a crucial step in angiogenesis. Here we report the identification of EDF-1, a novel gene product that is down-regulated when endothelial cells are induced to differentiate in vitro. The cDNA encoding EDF-1 was isolated by RNA fingerprinting from human endothelial cells exposed to human immunodeficiency virus type 1 Tat, a viral protein known to be angiogenic. The deduced amino acid sequence of EDF-1 encodes a basic intracellular protein of 148 amino acids that is homologous to MBF1 (multiprotein-bridging factor 1) of the silkworm Bombyx mori and to H7, which is implicated in the early developmental events of Dictyostelium discoideum. Interestingly, human immunodeficiency virus type 1 Tat, which affects endothelial functions, and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate and culture on fibrin gels, which promote endothelial differentiation in vitro, all down-regulate EDF-1 expression both at the RNA and protein levels. In addition, the inhibition of EDF-1 translation by an antisense anti-EDF-1 construct results in the inhibition of endothelial cell growth and in the transition from a nonpolar cobblestone phenotype to a polar fibroblast-like phenotype. These data suggest that EDF-1 may play a role in the regulation of human endothelial cell differentiation.