Short communication: Translational efficiency of casein transcripts in Mediterranean river buffalo.

Buffalo milk is characterized by the presence of all 4 casein fractions (α(S1), ß, α(S2), and κ) encoded by the 4 tightly linked autosomal genes (CSN1S1, CSN2, CSN1S2, and CSN3, respectively). In the present paper, we report for the first time a quantitative characterization of buffalo casein transcripts and show that the 4 genes are not transcribed and translated with the same efficiency. In particular, the analysis of individual milk samples obtained from 9 Mediterranean river buffaloes showed that the most abundant casein fractions were ß (53.45%) and α(S1) (20.61%), followed by α(S2) and κ, at 14.28 and 11.66%, respectively. Quantification of the corresponding mRNA showed that the percentage of transcripts of the 4 caseins was 16.48, 23.18, 55.87, and 4.47% for α(S1), ß, α(S2), and κ, respectively. Translation efficiency was 0.25 for CSN1S2, 1.31 for CSN1S1, 2.39 for CSN2, and 2.69 for the CSN3 transcripts, respectively. A comparison of nucleotide sequences with the Kozak consensus sequence was also carried out to investigate if the mRNA sequences might be responsible for the observed differences.

Sequence analysis and genetic variability of stearoyl CoA desaturase (SCD) gene in the Italian Mediterranean river buffalo.

Stearoyl-CoA desaturase (SCD) plays a key metabolic role by changing the saturated FA content of ruminant milk and meat. In this study we characterized for the first time the stearoyl-CoA desaturase (SCD) gene in river buffalo (Bubalus bubalis) and investigated its genetic variability. On a total of 78 buffaloes, 15 SNPs were detected and 6 of them were preliminarily genotyped. In particular, the g.133A>C SNP was found to create a new consensus site for the SP1 binding site, thus generating a new tandem repeat in the promoter region. A preliminary association study with the milk fatty acid content showed that the C allele significantly affects the total desaturation index (P<0.01). Linkage disequilibrium analysis allowed identification of 7 haplotypes and 4 tag SNPs. Such polymorphisms could represent useful genetic markers for association studies with fatty acid composition, but further studies are needed to evaluate their potential use to improve the nutritional quality of the dairy products.

Investigating the relationship between raw milk bacterial composition, as described by intergenic transcribed spacer-PCR fingerprinting, and pasture altitude.

AIMS: To assess the bacterial biodiversity level in bovine raw milk used to produce Fontina, a Protected Designation of Origin cheese manufactured at high-altitude pastures and in valleys of Valle d'Aosta region (North-western Italian Alps) without any starters. To study the relation between microbial composition and pasture altitude, in order to distinguish high-altitude milk against valley and lowland milk. METHODS AND RESULTS: The microflora from milks sampled at different alpine pasture, valley and lowland farms were fingerprinted by PCR of the 16S-23S intergenic transcribed spacers (ITS-PCR). The resulting band patterns were analysed by generalized multivariate statistical techniques to handle discrete (band presence-absence) and continuous (altitude) information. The fingerprints featured numerous bands and marked variability indicating complex, differentiated bacterial communities. Alpine pasture milks were distinguished from lowland ones by cluster analysis, while this technique less clearly discriminated alpine pasture and valley samples. Generalized principal component analysis and clustering-after-ordination enabled a more effective distinction of alpine pasture, valley and lowland samples. CONCLUSIONS: Alpine raw milks for Fontina production contain highly diverse bacterial communities, the composition of which is related to the altitude of the pasture where milk was produced. SIGNIFICANCE AND IMPACT OF THE STUDY: This research may provide analytical support to the important issue represented by the authentication of the geographical origin of alpine milk productions.

Genetic traceability of the geographical origin of typical Italian water buffalo Mozzarella cheese: a preliminary approach.

AIMS: To distinguish Italian Protected Designation of Origin (PDO) water buffalo Mozzarella from different producers on a molecular basis in relation to the place of manufacturing within the production district, and to develop a tool for genetic traceability of typical dairy products. METHODS AND RESULTS: Microbial DNA was isolated from Mozzarella's governing liquid to amplify the whole microflora's ribosomal 16S-23S internal transcribed spacers (ITS)-PCR fingerprinting by means of an original primer pair. Phylogenetic distance analyses were performed on the obtained electrophoretic band patterns by maximum parsimony and neighbour-joining tree construction algorithms for discrete binary data, using a conventional bootstrap resampling test. The observed band profiles showed high repeatability and specificity, allowing unambiguous distinction of each sample; phylogenetic analyses yielded the same tree topology with good strength of nodal support. Moreover, a relationship between the genetic distances among samples and the actual geographical ones separating the respective producing dairies was observed. CONCLUSIONS: The genetic diversity of PDO water buffalo Mozzarella's microflora, observed by ITS-PCR fingerprinting, can be exploited to discriminate cheeses from differently located dairies. SIGNIFICANCE AND IMPACT OF THE STUDY: Given the increasing importance of food traceability for safety, quality and typicalness issues, the ITS-PCR fingerprinting protocol described here may represent a suitable tool for tracing the geographical origin of Italian Mozzarella.