Search results for "lactic acid"
showing 10 items of 660 documents
Ecology and technological capability of lactic acid bacteria isolated during Grillo grape vinification in the Marsala production area
2011
Grapes of the “Grillo” variety, used to produce Marsala wine, were harvested from five vineyards with different climatic and agronomic parameters, in order to obtain a first mapping of lactic acid bacteria (LAB) inhabiting the production area. Marsala base wine production was followed at a large-scale, and also two experimental vinifications, with different lysozyme and SO2 concentrations and in combination, were carried out at pilot-plant scale. LAB communities and conventional chemical parameters were periodically analysed. LAB were found on grapes at an average concentration of about 102 CFU g−1 which decreased during the transformation process. A total of 146 colonies were collected, bu…
Effect of reducing agents on the acidification capacity and the proton motive force of Lactococcus lactis ssp. cremoris resting cells.
2002
International audience; Reducing agents are potential inhibitors of the microbial growth. We have shown recently that dithiothreitol (DTT), NaBH(4) and H(2) can modify the proton motive force of resting cells of Escherichia coli by increasing the membrane protons permeability [Eur. J. Biochem. 262 (1999) 595]. In the present work, the effect of reducing agents on the resting cells of Lactococcus lactis ssp. cremoris, a species widely employed in dairy processes was investigated. DTT did not affect the acidification nor the DeltapH, in contrast to the effect previously reported on E. coli. The DeltaPsi was slightly increased (30 mV) at low pH (pH 4) in the presence of 31 mM DTT or 2.6 mM NaB…
Extracellular oxidoreduction potential modifies carbon and electron flow in Escherichia coli.
2000
ABSTRACT Wild-type Escherichia coli K-12 ferments glucose to a mixture of ethanol and acetic, lactic, formic, and succinic acids. In anoxic chemostat culture at four dilution rates and two different oxidoreduction potentials (ORP), this strain generated a spectrum of products which depended on ORP. Whatever the dilution rate tested, in low reducing conditions (−100 mV), the production of formate, acetate, ethanol, and lactate was in molar proportions of approximately 2.5:1:1:0.3, and in high reducing conditions (−320 mV), the production was in molar proportions of 2:0.6:1:2. The modification of metabolic fluxes was due to an ORP effect on the synthesis or stability of some fermentation enzy…
Screening of lactic acid bacteria for reducing power using a tetrazolium salt reduction method on milk agar.
2013
WOS:000315703100020 ; www.elsevier.com/locate/jbiosc; International audience; Reducing activity is a physiological property of lactic acid bacteria (LAB) of technological importance. We developed a solid medium with tetrazolium dyes enabling weakly and strongly reducing LAB to be discriminated. It was used to quantify populations in a mixed culture (spreading method) and screen strains (spot method).
Galactosylated micelles for a ribavirin prodrug targeting to hepatocytes.
2013
Polymeric micelles potentially able to carry to hepatocytes a ribavirin (RBV) prodrug, exploiting the presence of carbohydrate receptors, that is, ASGPR, were prepared starting from a galactosylated polylactide-polyaminoacid conjugate. This latter was obtained by chemical reaction of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-dl-aspartamide (PHEA-EDA) with polylactic acid (PLA), and subsequent reaction with lactose, obtaining PHEA-EDA-PLA-GAL copolymer. To enhance the entrapment into obtained nanostructures, a hydrophobic RBV prodrug, that is, RBV tripalmitate, was synthesized and its capability to release RBV in the presence of an adequate enzymatic activity was demonstrated. Liver…
SELF-ASSEMBLED AMPHIPHILIC HYALURONIC ACID GRAFT COPOLYMERS FOR TARGETED RELEASE OF ANTITUMORAL DRUG
2009
Polymeric micelles obtained by self-assembling of amphiphilic hyaluronic acid (HA) graft copolymers have been prepared and characterized. In particular, hyaluronic acid (HA) has been grafted to polylactic acid (PLA) and polyethylenglycol chains (PEG), then the copolymers able to form micelles in aqueous medium have been chosen to entrap the antitumoral drug Doxorubicin. The critical aggregation concentration of HA-g-PLA or HA-g-PLA-g-PEG micelles has been determined by using pyrene as a fluorescent probe, whereas their shape and size have been evaluated by light scattering measurements, scanning and transmission electron microscopies. The selective cytotoxicity of drug loaded micelles towar…
LDHA-Associated Lactic Acid Production Blunts Tumor Immunosurveillance by T and NK Cells
2015
Elevated lactate dehydrogenase A (LDHA) expression is associated with poor outcome in tumor patients. Here we show that LDHA-associated lactic acid accumulation in melanomas inhibits tumor surveillance by T and NK cells. In immunocompetent C57BL/6 mice, tumors with reduced lactic acid production (Ldhalow) developed significantly slower than control tumors and showed increased infiltration with IFN-γ-producing T and NK cells. However, in Rag2-/-γc-/- mice, lacking lymphocytes and NK cells, and in Ifng-/- mice, Ldhalow and control cells formed tumors at similar rates. Pathophysiological concentrations of lactic acid prevented upregulation of nuclear factor of activated T cells (NFAT) in T and…
Effects of short-term methionine and cysteine restriction and enrichment with polyunsaturated fatty acids on oral glucose tolerance, plasma amino aci…
2021
Abstract Objective In this 7-day pilot study we randomized healthy, normal-weight men and women to either a dietary intervention with methionine and cysteine restriction enriched in PUFA (Met/Cyslow + PUFA, n = 7) or with high contents of methionine, cysteine and SFA (Met/Cyshigh + SFA, n = 7). The objective was to describe the short-term responses in oral glucose tolerance, amino acid profile, total fatty acid profile, pyruvate and lactate following a Met/Cyslow + PUFA diet vs. Met/Cyshigh + SFA. Results The diet groups consisted of five women and two men, aged 20–38 years. After the 7-d intervention median pre- and post-oral glucose tolerance test (OGTT) glucose concentrations were 5 mmol…
Cerebral metabolism after transient ischemic attack. A 1H MR spectroscopy study
1999
International audience; Abstract: Metabolic changes induced by cerebral infarction or by stenosis and occlusion of the internal carotid artery have been previously described in 1H Magnetic Resonance Spectroscopy (1H MRS). These changes are essentially characterized by decreased N-acetyl-aspartate (NAA) and increased lactate concentration. Little is known about the metabolic changes observed in the three days following a transient ischemic attack (TIA) in the absence of stenosis or occlusion of the internal carotid artery, and without visible infarction on Magnetic Resonance imaging (MRI). We studied five patients with a TIA lasting between 30 min and 3 h, affecting the sensory and motor fun…
Effects of resistance training frequency on cardiorespiratory fitness in older men and women during intervention and follow-up.
2017
This study investigated the effects of resistance training (RT) performed with different frequencies, including a follow-up period, on cardiorespiratory fitness in healthy older individuals. Eighty-eight men and women (69 ± 3 years, 167 ± 9 cm and 78 ± 14 kg) were randomly placed into four groups: training one- (M1 = 11, W1 = 12), two- (M2 = 7, W2 = 14), or three- (M3 = 11, W3 = 13) times-per-week or a non-training control group (MCon = 11, WCon = 9). During months 1–3, all subjects trained two-times-per-week while during the subsequent 6 months, training frequency was set according to the group. Oxygen consumption (cycling economy: CE), gross efficiency (GE), blood lactate concentrations (…