Search results for "lactobacillus"
showing 10 items of 353 documents
Two Methods for Highlighting the Influence of Sugars Type on Fermentation Processes Produced by Staphylococcus Carnosus and Lactobacillus Curvatus
2011
Purpose of this paper is to establish the influence of different types of sugars on fermentation processes found in the meat industry. In the analysis used a mixture of bacteria (Lactobacillus curvatus and Staphylococcus carnosus ), and the types of sugars were used lactose, lactulose, sucrose and two types of glucose syrup. To highlight the speed with which the fermentation process takes place, the variation in pH for the environment and the amount of energy released during biotechnological processes was measured.
Inactivation of the ftsH gene of Lactobacillus plantarum WCFS1: Effects on growth, stress tolerance, cell surface properties and biofilm formation
2012
FtsH proteins are ubiquitous membrane-bound, ATP-dependent metalloproteases of the AAA family. In eubacteria, FtsH is involved in protein quality control under stress conditions. Lactobacillus plantarum is a widespread lactic acid bacterium that is encountered in several fermented food, including dairy products, vegetables and meat. In the present work the expression of the ftsH gene of L. plantarum was studied by quantitative real time RT-PCR in bacterial cultures subjected to various abiotic stresses. Both oxidative stress and addition of a membrane-fluidizing agent induced ftsH transcription, while a depletion of carbon-source repressed its mRNA level. Mutants deprived of the FtsH protea…
No invasive methodology to produce a probiotic low humid apple snack with potential effect against Helicobacter pylori
2012
Abstract A probiotic low humid apple snack with potential effect against the infection caused by Helicobacter pylori has been developed from apple (cv. Granny Smith) and mandarin juice with a high microbial content of Lactobacillus salivarius spp . salivarius , by vacuum impregnation and hot air drying techniques. The moisture content reached in the final product (0.144 ± 0.012 g water · g sample - 1 ) ensured stability, and although the drying process affected the microbial content, the concentration in the final product (9.486 ± 0.013) × 10 7 CFU g dry sample - 1 ) was sufficient to confirm that with this procedure it is possible to obtain a stable probiotic fruit with a low moisture c…
Monitoraggio del ceppo starter Lactobacillus pentosus OM13 nella fermentazione delle olive da tavola (cv. “Nocellara del Belice”) con lavorazione siv…
2014
Obiettivo di questa ricerca . stato validare le attitudini tecnologiche alla trasformazione di olive da mensa cv. “Nocellara del Belice” da parte del ceppo Lactobacillus pentosus OM13. Lo starter Lb. pentosus OM13 ha dimostrato di dominare l’intero processo fermentativo e ha determinato un sensibile abbassamento del pH, inibendo cos. lo sviluppo di microrganismi potenzialmente patogeni e/o alterativi. All’inizio della sperimentazione e fino al 16¢X giorno di fermentazione, i lieviti hanno mostrato un incremento in entrambe le lavorazioni, con starter e di controllo, ma con un livello di carica microbica maggiore nella tesi di controllo. Nella fase di sperimentazione, successiva al 16¢X gior…
Polyphasic Characterization of Microbiota of “Mastredda”, a Traditional Wooden Tool Used during the Production of PDO Provola dei Nebrodi Cheese
2021
The biofilms of the wooden tables used for the acidification of the curd were investigated for PDO Provola dei Nebrodi cheese, a traditional stretched cheese made in eastern Sicily (southern Italy) from raw cows’ milk. To this purpose the wooden tables of four dairy facilities were analysed for their microbiota by scanning electron microscopy (SEM) analysis and a combined culture-independent and -dependent microbiological approach. SEM inspection showed an almost continuous biofilm formation. MiSeq Illumina analysis identified 8 phyla, 16 classes, 25 orders, 47 families and 50 genera. Corynebacterium, Bifidobacterium and lactic acid bacteria (LAB) were detected in all samples. In particular…
Microbial dynamics in durum wheat kernels during aging
2020
In the present work the microbial dynamics in wheat kernels were evaluated over time. The main aim of this research was to study the resistance of lactic acid bacteria (LAB) and yeasts associated to unprocessed cereals used for bread making during long term conservation. To this purpose four Triticum durum Desf. genotypes including two modern varieties (Claudio and Simeto) and two Sicilian wheat landraces (Russello and Timilia) were analysed by a combined culture-independent and -dependent microbiological approach after one, two or three years from cultivation and threshing. DNA based MiSeq Illumina technology was applied to reveal the entire bacterial composition of all semolina samples. T…
Intraspecific diversity of Lactobacillus curvatus, Lactobacillus plantarum, Lactobacillus sakei, and Leuconostoc mesenteroides associated with vacuum…
2006
The intraspecific diversity of Leuconostoc mesenteroides, Lactobacillus curvatus, Lactobacillus sakei, and Lactobacillus plantarum was analyzed by randomly amplified polymorphic DNA (RAPD) PCR with universal primers M13 and T3. The study included 100 reference strains and 210 isolates recovered from two vacuum-packed Spanish meat products, fiambre de magro adobado and morcilla, previously identified by rDNA-restriction fragment length polymorphism profiles. The RAPD-M13 profiles identified isolates at species level in L. plantarum and L. mesenteroides, while RAPD-T3 provided profiles in L. sakei. The combination of RAPD-M13 and RAPD-T3 fingerprints revealed a total of 17 profiles in L. mese…
Molecular characterization of an inducible p-coumaric acid decarboxylase from Lactobacillus plantarum: gene cloning, transcriptional analysis, overex…
1997
By using degenerate primers designed from the first 19 N-terminal amino acids of Lactobacillus plantarum p-coumaric acid decarboxylase (PDC), a 56-bp fragment was amplified from L. plantarum in PCRs and used as a probe for screening an L. plantarum genomic bank. Of the 2,880 clones in the genomic bank, one was isolated by colony hybridization and contained a 519-bp open reading frame (pdc gene) followed by a putative terminator structure. The pdc gene is expressed on a monocistronic transcriptional unit, which is transcribed from promoter sequences homologous to Lactococcus promoter sequences. No mRNA from pdc and no PDC activity were detected in uninduced cell extracts, indicating that the…
Functional genomics of Lactobacillus casei establishment in the gut
2014
International audience; Although the composition of the gut microbiota and its symbiotic contribution to key host physiological functions are well established, little is known as yet about the bacterial factors that account for this symbiosis. We selected Lactobacillus casei as a model microorganism to proceed to genomewide identification of the functions required for a symbiont to establish colonization in the gut. As a result of our recent development of a transposon-mutagenesis tool that overcomes the barrier that had prevented L. casei random mutagenesis, we developed a signature-tagged mutagenesis approach combining whole-genome reverse genetics using a set of tagged transposons and in…
Identification and transcriptional profile of Lactobacillus paracasei genes involved in the response to desiccation and rehydration
2020
International audience; Lactobacillus paracasei is able to persist in a variety of natural and technological environments despite physico-chemical perturbations, in particular alternations between desiccation and rehydration. However, the way in which it adapts to hydric fluctuations and the genetic determinants involved are not clearly understood. To identify the genes involved in adaptation to desiccation, an annotated library of L. paracasei random transposon mutants was screened for viability after desiccation (25% relative humidity, 25 °C). We found 16 genes that have not been described as being involved in this response. Most of them are linked to either the transport of molecules or …