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The hemolytic ability, the presence of cyl genes, and the diagnostic accuracy of cytolysin molecular detection were investigated in the genus Enterococcus by using 164 strains from 20 different species (26 reference strains, 42 clinical isolates from human and veterinary origin, and 96 isolates from ewe cheese and milk). Hemolysis was assayed with sheep and horse erythrocytes and under aerobic or anaerobic conditions. Screening of cytolysin genes (cylL L , cylL S , cylM, cylB, and cylA) was performed with new specific primers and the anaerobic assay of beta-hemolysis was used as the "gold standard" for the evaluation of cyl gene-based PCRs. Since beta-hemolysis and cyl genes were found in 10 and 14 species, respectively, the hemolytic ability seems to be spread throughout the genus Enterococcus. Beta-hemolysis was observed in 6 of 26 (23%) reference strains, 14 of 42 (33%) clinical isolates, and 6 of 96 (6%) food isolates. The presence of cyl genes was detected in 15 of 26 (58%) reference strains, 37 of 42 (88%) clinical isolates, and 67 of 96 (70%) food isolates. These data indicate a virulence potential in food isolates, reinforcing the need of their safety assessment. Analysis of phenotypicgenotypic congruence suggests a divergent sequence evolution of cyl genes and the effect of environmental factors in the regulation of cytolysin expression. Evaluation of the diagnostic accuracy of cytolysin molecular detection points to cylL L -based PCR and cylL L L S MBA-based PCR as the most reliable approaches. Nevertheless, the low sensitivity (46%) and gene variability indicated by our study strongly recommend the phenotypic assay for the assessment of hemolytic ability in enterococci, followed by the molecular screening of cyl genes in nonhemolytic strains to evaluate their virulence potential.

One of the pathways for the entry of bacteria, both pathogenic and probiotic, into the larvae of fish hatcheries is via live prey. As a preventive measure against infections, live prey may be cultured, supplementing the food with probiotics. Some lactic acid bacteria (LAB) have been successfully used in the larviculture. In this study, the nutritional effect of seven terrestrial LAB has been studied regarding the growth of the rotifer Brachionus plicatilis. The cultures were carried out without partial renewal of the culture medium, feeding the rotifers on baker's yeast and adding some of the species of bacteria. In all cases, the addition of the bacteria increased both the specific maximum growth rate and the maximum density obtainable in the cultures. However, the best results were obtained with the addition of Lactococcus lactis spp lactis, Pediococcus acidilactici or Lactobacillus casei ssp. casei. The rates of growth obtained with the individual or joint addition of these three bacteria were 8-13 times greater than those obtained with the control cultures after 4-5 days' culture. In this study, a series of kinetic models have been applied (logistic modified−Gompertz, logistic−logistic and generalised logistic) which describe the experimental data, obtaining a set of parameters of biological significance which facilitate the optimisation of the use of these bacterial strains in the mass production of rotifers.

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The manufacturing process of cork stoppers includes a stabilization period of the cork slabs, following boiling, during which mold growth completely covers the cork slabs. This process has been used traditionally for several decades; however, due to the possibility of certain molds isolated from cork to produce off flavor compounds, especially 2,4,6-trichloroanisole and 2,3,4,6-tetrachloroanisole, recently cork stoppers are being unsoundly targeted with the accusation of inducing cork taint in wine. This article reviews the manufacturing process of cork stoppers, the diversity of microorganisms associated with cork, and finally the diversity and origins of the compounds associated with cork taint in wine, focusing on those currently considered as more important. Some important results recently obtained by the authors are also included. The current idea of suppressing mold growth during cork stopper manufacturing is discussed, as well as the erroneous idea of imputing, directly and exclusively, to cork the responsibility of the so-called cork taint in wine.

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