María del Carmen López Rodríguez

Characterization of lactic acid bacteria from musts and wines of three consecutive vintages of Ribeira Sacra

Aims:  This study was designed to isolate and characterize the lactic acid microbiota of the musts and wines of a young denomination of origin area, Ribeira Sacra in north‐west Spain.

Synthesis, biological evaluation and SAR studies of novel bicyclic antitumor platinum(IV) complexes

The present study describes the synthesis, anticancer activity and SAR studies of novel platinum(IV) complexes having 1,2-bis(aminomethyl)carbobicyclic or oxabicyclic carrier ligands, bearing chlorido and/or hydroxido ligands in axial position and chlorido or malonato ligands in equatorial position (labile ligands). These complexes were synthetized with the aim of obtaining new anticancer principles more soluble in water and therefore more bioavailable. Several substitution patterns on the platinum atom have been designed in order to evaluate their antiproliferative activity and to establish structure-activity relationship rules. The synthesis of platinum(IV) complexes with axial hydroxyl ligands on the platinum(IV) were carried out by reaction of K2Pt(OH)2Cl4 with the corresponding diamines. The complexes with axial chlorido ligands on the platinum(IV) atom were synthesized by direct reaction of diamines with K2PtCl6. Carboxylated complexes were synthesized by the substitution reaction of equatorial chlorido ligands by silver dicarboxylates. The most actives complexes were those having malonate as a labile ligand, no matter of the structure of the carrier ligand. Regarding the influence of the structure of the non-labile 1,4-diamine carrier ligand on the cytotoxicity, it was found that the complexes having the more lipophilic and symmetrical bicyclo[2.2.2]octane framework were much more active than those having an oxygen or methylene bridge.

Basic characterization and partial purification of β‐glucosidase from cell‐free extracts of Oenococcus oeni ST81

Aims:  This study was designed to characterize a β‐glucosidase of Oenococcus oeni ST81, a strain isolated from a Spanish wine of the origin appellation Ribeira Sacra.

pRS4: UN VECTOR DE CLONACIÓN IDÓNEO PARA BACTERIAS ÁCIDO-LÁCTICAS DE USO ALIMENTARIO pRS4: AN APPROPRIATE CLONING VECTOR FOR LACTIC-ACID BACTERIA OF FOOD USE

Abstract The ability of pRS4, a cryptic plasmid from Pediococcus pentosaceus, as a selective cloning vector for lactic acid bacteria has been analysed. The results indicate that pRS4C1, a cloning vector from pRS4 can stably transform Lactobacillus plantarum, Pediococcus acidilactici and P. pentosaceus (three lactic acid bacteria used as starters in the food industry) but it does not transform Enterococcus faecalis (a lactic acid bacteria which is undesirable due to its potential origin, mainly of faecal source). Further modifications of the pRS4C1, consisting in positional changes of the chloramphenicol resistance marker and/or single mutation into the initiation codon of the gene of the replication protein, does not generate expression of pRS4 into E. faecalis, however the ability of these derivates to transform Lactobacillus and Pediococcus remains unaltered. These results indicate that pRS4 can be used as a selective cloning vector for genetic manipulation of useful lactic acid bacteria, without risk of horizontal transfer of genetic material to undesirable lactic acid bacteria that could coexist with the formers. Resumen Se ha analizado la posibilidad de utilizar pRS4, un plásmido críptico de Pediococcus pentosaceus, como vector selectivo de clonación en bacterias ácido-lácticas. Los resultados obtenidos indican que pRS4C1, vector de clonación derivado de pRS4, transforma en forma estable Lactobacillus plantarum, Pediococcus acidilactici y P. pentosaceus, bacterias ácido-lácticas utilizadas como cultivos iniciadores en la industria alimentaria, pero no transforma Enterococcus faecalis, una bacteria ácido-láctica cuya presencia en alimentos es considerada indeseable por su habitual procedencia de origen fecal. Posteriores modificaciones de pRS4C1, consistentes en cambios de posición del marcador de resistencia a cloranfenicol y/o mutación puntual del codon de iniciación del gen que codifica para la proteína de replicación, no subsanan la carencia de expresión de pRS4 en E. faecalis, pero mantienen inalterable su capacidad de transformar y expresarse establemente en las especies de Lactobacillus y Pediococcus arriba citadas. Estos resultados indican que pRS4 puede ser utilizado como vehículo de clonación selectivo para la manipulación genética de bacterias ácido-lácticas útiles, sin riesgo de transferencia horizontal de material genético a determinadas bacterias ácido-lácticas indeseables, que puedan coexistir con las primeras en un mismo alimento. Palabras clave: Bacterias ácido-lácticas, plásmidos, vectores de clonación

TOLERANCIA DE Oenococcus oeni RS1 A LAS CONDICIONES DE ESTRÉS DEL VINO TOLERANCE OF Oenococcus oeni RS1 TO STRESS ENVIRONMENTAL CONDITIONS OF WINE TOLERANCIA DE Oenococcus oeni RS1 ÁS CONDICIÓNS DE ESTRÉS DO VIÑO

Abstract The tolerance of Oenococcus oeni RS1 to different stress conditions of the wine, its natural habitat, has been studied. The results obtained indicate that, in our assay conditions, the O. oeni RS1 strain exhibit high tolerance to the adverse environmental conditions given by the wine (temperature, high acidity, presence of SO2, ethanol, aromas and metals). In the other hand, when the RS1 strain, who carries the plasmid pRS1, is compared with the RS1C7 strain, who lacks it, the implication of the plasmid pRS1 on the resistance mechanism to the stress conditions gave by antioxidant compounds as SO2 and geraniol can be concluded.