Colour evaluation of Pinot Noir and Merlot Wines after malolactic fermentation carried out by Oenococcus oeni and Lactobacillus plantarum Patagonian Native Strains

Malolactic fermentation is a complex process that involves many reactions aside from the decarboxylation of L-malic acid. But we still have only glimpses of that complexity. It is not clear if the phenolic composition and colour are affected by malolactic fermentation and, if so, to what extent. So, the aims of this study were: 1) to evaluate the behaviour of native Patagonian strains of Oenococcus oeni and Lactobacillus plantarum in two wine varieties, and 2) to analyse the effect of malolactic fermentation on the colour of these wines. Our results show that the survival of bacteria and L-malic acid decarboxylation is different depending on the lactic acid bacteria strain employed and the wine variety. In addition, we found that O. oeni can survive in wine even when L-malic acid is not being consumed. We found some correlations between MLF and colour-related parameters in Pinot noir but not for Merlot. In fact, some of the colour-related parameters measured in Merlot (total polyphenolic index, colour intensity, hue, as well as the CIELAB parameters) were affected even when L-malic acid was not being consumed.Fil: Olguin, Nair Temis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Delfederico, Lucrecia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Evaluation of the Defay-Prigogine model for the membrane interphase in relation to biological response in membrane-protein interactions

Surface water activity appears as a common factor when the interaction of several aqueous soluble and surface active proteins with lipid membranes of different composition is measured by the changes in surface pressure of a lipid monolayer. The perturbation of the lipid surface caused by aqueous soluble proteins depends on the composition of the hydrocarbon phases, either modified by unsaturated bonds in the acyl chains or by inclusion of cholesterol. The cut-off (critical) surface pressure in monolayers, at which no effect of the proteins is found, is related to the composition of the head group region. The perturbation of surface pressure is produced by proteins when the area per lipid is above just 4% larger than that corresponding to the hydration shell of the phospholipid head groups found in the cut -off. This area excess gives place to regions in which the chemical potential of water changes with respect to bulk water. According to the Defay-Prigogine relation this interfacial water activity is the reason of the surface pressure increase induced by aqueous soluble proteins injected in the subphase. As predicted by solution chemistry, the increase of surface pressure is independent of the protein nature but depends on the water surface state determined by the lipid composition.Fil: Disalvo, Edgardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero; Argentina;Fil: Hollmann, Axel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia. Laboratorio de Microbiologia Molecular; Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero; Argentina;Fil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina;Fil: Martini, María Florencia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina

Aplicación de un Enfoque Metagenómico al Estudio de la Diversidad Bacteriana asociada a Suelo, Rizósfera y Vinos de la Región Bonaerense Argentina

Durante la fermentación malolática (FML) las bacterias del ácido láctico (BAL) decarboxilan el ácido L-málico transformándolo en ácido L-láctico y contribuyen a la calidad del vino al reducir su acidez y aportar a su aroma y sabor. De este modo, las BAL aportan al terroir característico de cada vino, y su diversidad en el viñedo dependerá de factores como clima, suelo, varietal vínico y prácticas culturales y de vinificación. En la región vitícola bonaerense (Argentina) no existen aún estudios sobre la diversidad microbiológica asociada a suelos, vides, mostos y vinos, conocimiento crucial para seleccionar cepas indígenas con fines enológicos. Para iniciar este análisis se realizó la secuenciación masiva del gen 16S rRNA de muestras de suelo, rizósfera, mosto y vinos de dos bodegas del SO bonaerense (Saldungaray y Al Este, Buenos Aires, Argentina), obteniéndose 123.379 secuencias y 5.323 OTUs. Se observaron índices de diversidad elevados, con diferencias significativas entre muestras de suelo y rizósfera respecto de mosto y vino. Los análisis taxonómicos mostraron como filo mayoritario en suelo y rizósfera a Proteobacteria (especialmente Alphaproteobacteria, con predominancia de Rhizobiales), y en mosto y vino a Proteobacteria, con predominancia de las Alphaproteobacteria Rhodospirillales y Sphingomonadales. Estos hallazgos, constituyen un primer aporte al conocimiento de las comunidades bacterianas de una región vitivinícola en desarrollo y contribuirán a optimizar procesos productivos y prácticas agrícolas sustentables.Trabajo en relación con PIT AP-BA Número 173/16, presentado en Jornadas de Jóvenes Investigadores en la Universidad Federal de San Carlos (UFSCAR), Brasil

Antimicrobial activity of de novo designed cationic peptides against multi-resistant clinical isolates

Antibiotic resistance is one of the main problems concerning public health or clinical practice. Antimicrobial peptides appear as good candidates for the development of new therapeutic drugs. In this study we de novo designed a group of cationic antimicrobial peptides, analyzed its physicochemical properties, including its structure by circular dichroism and studied its antimicrobial properties against a panel of clinical isolates expressing different mechanisms of resistance. Three cationic alpha helical peptides exhibited antimicrobial activity comparable to, or even better than the comparator omiganan (MBI-226).Fil: Faccone, Diego Francisco. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Veliz, Omar. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Corso, Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Noguera, Martín Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martínez, Melina María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Payés, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Maffia, Paulo Cesar. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Antimicrobial peptides: Interaction with model and biological membranes and synergism with chemical antibiotics

Antimicrobial peptides (AMPs) are promising novel antibiotics since they have shown antimicrobial activity against a wide range of bacterial species, including multiresistant bacteria; however, toxicity is the major barrier to convert antimicrobial peptides into active drugs. A profound and proper understanding of the complex interactions between these peptides and biological membranes using biophysical tools and model membranes seems to be a key factor in the race to develop a suitable antimicrobial peptide therapy for clinical use. In the search for such therapy, different combined approaches with conventional antibiotics have been evaluated in recent years and demonstrated to improve the therapeutic potential of AMPs. Some of these approaches have revealed promising additive or synergistic activity between AMPs and chemical antibiotics. This review will give an insight into the possibilities that physicochemical tools can give in the AMPs research and also address the state of the art on the current promising combined therapies between AMPs and conventional antibiotics, which appear to be a plausible future opportunity for AMPs treatment.Fil: Hollmann, Axel. Universidad Nacional de Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Martínez, Melina María Belén. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Maturana, Patricia del Valle. Universidad Nacional de Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes; ArgentinaFil: Maffia, Paulo Cesar. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Sequence variability in p27 gene of Citrus Tristeza Virus (CTV) revealed by SSCP analysis

Citrus tristeza closterovirus (CTV), is a phloem-limited virus transmitted by aphids in a semipersistent manner. The genome of CTV is composed of a ssRNA with two capsid proteins: CP, covering about 95% of the particle length, and a diverged coat protein (dCP), present only in one end of the particle, forming a rattlesnake structure. dCP is the product of p27 gene for which it is also postulated a function in the transmissibility by aphid vectors. Hybridization analysis showed a p27 gene region, which exhibits different patterns with two probes derived from two biological distinct CTV isolates. In an attempt to screen whether that gene region differs in mild and severe strains, six CTV isolates belonging to different biogroups were compared for variations in their p27 gene by analysis of single-strand conformation polymorphism (SSCP). The p27 gene was reverse transcribed and amplified by PCR and thirty clones of each isolate were obtained. From each clone, two fragments of the gene were amplified by PCR: fragment (a), 459 bp long, and fragment (b), 281 bp long. Sequence variations in both gene fragments were studied by SSCP analysis. A variety of SSCP patterns was obtained from each isolate, being isolates belonging to the groups II-IV and III those with the higher and lower number of them. Moreover, SSCP analysis provided a rapid procedure to screen the genetic heterogeneity of the viral isolates reducing considerably the amount of nucleic acid sequenciation necessary to gain that knowledge.Instituto de Biotecnología y Biología Molecula

Prevalence of Lentilacobacillus hilgardii over Lactiplantibacillus plantarum in Low-Temperature Spontaneous Malolactic Fermentation of a Patagonian Pinot Noir

The spontaneous malolactic fermentation (MLF) in a centenary winery from Patagonia, Argentina, is conducted by predominantly mesophilic Oenococcus oeni and Lactiplantibacillus plantarum. In this region, MLF takes place from 14 to 4 °C, leading to heat cellars incurring in higher costs and non-sustainable practices. Previously, psychrotrophic strains of O. oeni had been obtained from a Patagonian wine. The goal of this work was to identify the Lactobacillaceae microbiota related to low-temperature MLF and assess their contribution. Nine sychrotrophicc Lentilactibacillus hilgardii strains were identified by sequencing the 16S rRNA gene, and the strains typified by RAPD-PCR. All strains consumed L-malic acid at 4 and 10 °C in sterile wine. The selected UNQLh1.1 strain revealed implantation capacity and L-malic acid consumption at 4 and 10 °C in the presence of the native microbial consortium. Furthermore, the histidine decarboxylase (hdc) gene was not detected in any of the Len. hilgardii strains. The prevalence of Len. hilgardii under low-temperature conditions represents a novelty compared to previous findings of LAB diversity in the MLF of Patagonian wines. The native Patagonian psychrotrophic Len. hilgardii strains are a new player in fermentations conducted at low temperatures with the potential to be used as a sustainable MLF starter.Fil: Manera, Camila. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Rivas, Gabriel Alejandro. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Flores, Naiquen Elizabeth. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Brizuela, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Caballero, Adriana Carmen. Universidad Nacional del Comahue; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Valdes la Hens, Danay. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Restriction site patterns in the ribosomal DNA of Camelidae

The restriction map of rDNA from South American camelids and the Bactrian camel was analyzed by digestion of high-molecular-weight DNA with endonucleases EcoRI, BamHI and the two combined followed by Southern blot hybridization with probes for the 18S and 28S rDNA sequences. We scored a total of 17 restriction sites, six of which were mapped conserved in all the species. The other eleven corresponded to spacer regions and revealed variations between these taxa. The study showed that the two groups differ in the length of the internal transcribed spacer. Also they showed the existence of two regions of fast evolution on the opposite termini of the external spacer. A restriction site present at low frequency in the non-transcribed spacer of guanaco and llama was the only difference encountered within the South American group.Instituto Multidisciplinario de Biología Celula

Aislamiento y selección de cepas psicrotolerantes de bacterias lácticas enológicas de la región patagónica

La vinificación de varietales tintos patagónicos ocurre en abril y mayo, con bajas temperaturas ambientales que inhiben el progreso de la fermentación maloláctica (FML), por ser un factor de estrés para las bacterias lácticas (BAL) que conducen el proceso. Las bodegas deben calentar los tanques de fermentación, incrementando los costos de producción. El desarrollo de cultivos malolácticos nativos, tolerantes a bajas temperaturas, constituye una herramienta estratégica para resolver el problema y potenciar el carácter regional de los vinos. El objetivo del trabajo consistió en obtener cepas enológicas patagónicas de BAL, capaces de sobrevivir y consumir ácido L-málico en vinificaciones a bajas temperaturas (4 y 10 ºC). Los aislamientos psicrotolerantes procedieron de vino Pinot noir (bodega comercial de General Roca, Río Negro). Su identificación se realizó por secuenciación del gen 16S rRNA y la similitud genética se analizó por RAPD-PCR con el primer M13. Como primer criterio de selección se evaluó su supervivencia en vino estéril incubado a bajas temperaturas. Posteriormente, las cepas que exhibieron mejor tolerancia, UNQoE19 (O. oeni) y UNQLh1.1 (Lb. hilgardii), se inocularon en vino, a escala de laboratorio, y se evaluaron su supervivencia y sus capacidades de implantación y de consumo de ácido L-málico, con resultados promisorios

Complete Genome Sequencing of Lactobacillus plantarum UNQLp 11 Isolated from a Patagonian Pinot Noir Wine

Lactobacillus plantarum UNQLp 11 strain was isolated from a Patagonian Pinot noir wine at the oldest commercial winery (110 years old) in General Roca, North Patagonia, Argentina, and has demonstrated its ability to survive during winemaking processes and successfully carry out malolactic fermentation. This work aimed to obtain the whole assembled genome of the UNQLp 11 strain, analysing its architecture and the possible functions of the predicted genes from the oenological properties of this strain. The genome size is 3 534 932 bp, with a mean GC content of 44.2%, 3 412 CDS, 80 transposons and 148 tandem repeats. A comparison between the genome size and gene content of 14 Lb. plantarum strains from different origins was performed, and UNQLp 11 exhibited the largest size. The in silico genome-wide analysis allowed us to confirm the existence of genes encoding enzymes involved in the synthesis of several metabolites of oenological interest, in addition to bacteriocins and exopolysaccharides. Furthermore, it is possible to speculate on this strain’s adaptation to different environments, as it is able to use diverse substrates for its growth. All these features suggest the potential of UNQLp 11 to be a good starter culture for malolactic fermentation.Fil: Iglesias, Nestor Gabriel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Instituto de Microbiología Básica y Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brizuela, Natalia Soledad. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tymczyszyn, Emma Elizabeth. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hollmann, Axel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; ArgentinaFil: Valdes la Hens, Danay. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; ArgentinaFil: Bravo Ferrada, Barbara Mercedes. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin