Search results for "Lactobacillus"
showing 10 items of 353 documents
Potential application of lactic acid bacteria in the biopreservation of red grape from mycotoxigenic fungi
2021
Background Filamentous fungi are the main contamination agent in the viticultural sector. Use of synthetic fungicides is the regular answer to these contaminations. Nevertheless, due to several problems associated with the use of synthetic compounds the industry demands new and safer methods. In the present work, the biopreservation potential of four lactic acid bacteria (LAB) strains was studied against the principal grape contaminant fungi. Results Agar diffusion test evidenced that all four culture-free supernatant (CFS) had antifungal properties against all tested fungi. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) test values evidenced that medi…
Ochratoxin A removal in synthetic media by living and heat-inactivated cells of Oenococcus oeni isolated from wines
2010
The capacity of Oenococcus oeni to eliminate ochratoxin A (OTA) from synthetic media in different conditions was studied. Ten tested O. oeni strains removed OTA from the medium but with significant differences depending on the strain, incubation period, and initial OTA level in the medium. Mycotoxin reductions higher than 60% were recorded in 14-day cultures spiked with 2 mu g OTA/l. Toxin removal was independent of bacterial viability and culture medium composition. This is the first study carried out to study OTA removal dynamics by living and heat-inactivated cells of O. oeni. The results aim that this bacterium may be a very useful tool to control OTA in food and beverages. (C) 2009 Els…
Evoluzione della microflora durante il processo fermentativo “Sivigliano” di olive da tavola “Nocellara del Belice”
2008
Una lavorazione tipo “Sivigliano” di olive della varietà “Nocellara del Belice”, provenienti da coltura in irriguo e non, è stata sottoposta a monitoraggio chimico-fisico e microbiologico periodico sino al 150° giorno di fermentazione. La tecnologia adottata su tre repliche da 500 Kg ha previsto l’aggiunta di soda a 2,2°Bè a scopo di deamarizzare le olive in bagno alcalino e sei lavaggi sequenziali allo scopo di neutralizzare l’alcalinità, al termine dei quali si è provveduto alla colmatura con salamoia concentrata a 10°Bé. Il monitoraggio del pH e della concentrazione di zuccheri riduttori ha evidenziato il buon andamento del processo fermentativo per entrambe le tesi considerate, sebbene …
Characterization of the CtsR stress response regulon in Lactobacillus plantarum.
2010
ABSTRACT Lactobacillus plantarum ctsR was characterized. ctsR was found to be cotranscribed with clpC and induced in response to various abiotic stresses. ctsR deletion conferred a heat-sensitive phenotype with peculiar cell morphological features. The transcriptional pattern of putative CtsR regulon genes was examined in the Δ ctsR mutant. Direct CtsR-dependent regulation was demonstrated by DNA-binding assays using recombinant CtsR and the promoters of the ctsR - clpC operon and hsp1 .
Assessment of cytotoxic and antimicrobial activities of two components of Cymbopogon citratus essential oil
2020
Background There is a continuing search for compuounds to improve the chemical plaque inhibitory action of oral hygiene products. Although the antibacterial effects of chlorhexidine (CHX) and essential oils components, citral/myrcene, have been described, there is contradictory information regarding their cytotoxic effects in host tissues. This study aimed to evaluate the cytotoxic activity of the major components of the oil C. citratus, citral and myrcene on human periodontal ligament fibroblast (HPLF) cultures and their antimicrobial effect on different bacterial species present in supragingival biofilm. Material and methods Cytotoxicity of the compounds to HPLF was determined by MTT assa…
Influence of Culture Medium on Multiplication of Lactic Bacteria Isolated From Organic Milk in Order to Obtain Biomass
2014
Abstract This paper aims to establish direct and predictive methods (statistical) the possibility of obtaining lactic bacteria Lactobacillus delbrueckii var. bulgaricus in higher amounts by using culture medium enriched with carbohydrates in different percentages, for using these in obtaining organic products. The results led to the selection of MRS culture medium enriched with 1% glucose, 2% lactose and 3% maltose as a substrate in order to use multiplication of lactic bacteria isolated from organic milk, collected from organic farms in the area of Sibiu, Romania.
Tyramine and phenylethylamine production among lactic acid bacteria isolated from wine.
2007
The ability of wine lactic acid bacteria to produce tyramine and phenylethylamine was investigated by biochemical and genetic methods. An easy and accurate plate medium was developed to detect tyramine-producer strains, and a specific PCR assay that detects the presence of tdc gene was employed. All strains possessing the tdc gene were shown to produce tyramine and phenylethylamine. Wines containing high quantities of tyramine and phenylethylamine were found to contain Lactobacillus brevis or Lactobacillus hilgardii. The main tyramine producer was L. brevis. The ability to produce tyramine was absent or infrequent in the rest of the analysed wine species.
Nicotinamide Adenine Dinucleotide-Dependent and Nicotinamide Adenine Dinucleotide-Independent Lactate Dehydrogenases in Homofermentative and Heterofe…
1971
Three homofermentative ( Lactobacillus plantarum B38, L. plantarum B33, Pediococcus pentosaceus B30) and three heterofermentative ( Leuconostoc mesenteroides 39, L. oenos B70, Lactobacillus brevis ) lactic acid bacteria were examined for the presence or absence of nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent d - and l -lactate dehydrogenases. Two of the six strains investigated, P. pentosaceus and L. oenos , did not exhibit an NAD-independent enzyme activity capable of reducing dichlorophenol indophenol. The p H optima of the lactic dehydrogenases were determined. The NAD-dependent enzymes from homofermentative strains exhibited optima at p H 7.8 to 8.8, whereas va…
Dažādu kultivēšanas apstākļu ietekme uz Lactobacillus plantarum rezistenci pret oksidatīvo stresu
2020
Pienskābo baktēriju rezistence pret oksidatīvo stresu, kas cieši atkarīga no šūnu metabolisma, ir ļoti svarīga, lai tās varētu izmantot kā probiotikas. Darba mērķis bija novērtēt oksidatīvā stresa ietekmi uz L. plantarum kultūras enzimātisko aktivitāti pēc tās kultivēšanas dažādos apstākļos un aizsargvielu klātbūtnē. Oksidatīvā stresa ierosināšanai izmantots 1-2 mM H2O2 un 2-50 Gy jonizējošs starojums. Aizsargvielas – sulforafāns (SFA), sulforafēns (SFE). Salīdzinātas De Man, Rogosa and Sharpe (MRS) un Tryptone Soya Broth (TSB) barotnes. Barotnes sastāvs ietekmēja baktēriju augšanas kinētikas parametrus un reakciju uz oksidatīvo stresu. 1 μg/ml SFA vai SFE pievienošana kultūrām pirms apstar…
Use of selected autochthonous lactic acid bacteria for Spanish-style table olive fermentation
2012
The present work presents a successful attempt to achieve an enhanced and more predictable fermentation process in Spanish-style green olive technology by selection and use of autochthonous starter cultures. During the first phase of this work, two Spanish-like fermentations of green table olives of cultivar (cv) “Nocellara del Belice”, coming from irrigated and not irrigated fields, were monitored, in order to highlight the best agricultural conditions for drupe production and to isolate lactic acid bacteria strains with relevant technological properties. Among 88 identified isolates, one Lactobacillus pentosus strain showed remarkable biochemical features and high acidification rate in sy…