Microparticles of Novel Branched Copolymers of Lactic Acid and Amino Acids: Preparation and Characterization

1999 ◽  
Vol 88 (1) ◽  
pp. 136-141 ◽  
Author(s):  
Giovanni Caponetti ◽  
Jeffrey S. Hrkach ◽  
Burkhard Kriwet ◽  
Melissa Poh ◽  
Noah Lotan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Branched Copolymers

scholarly journals Chiroptical activity of hydroxycarboxylic acids with implications for the origin of biological homochirality

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jana Bocková ◽  
Nykola C. Jones ◽  
Uwe J. Meierhenrich ◽  
Søren V. Hoffmann ◽  
Cornelia Meinert
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Aliphatic Chain ◽  
Monocarboxylic Acids ◽  
Hydroxycarboxylic Acids ◽  
Polarised Light ◽  
Suitable Target ◽  
Anisotropy Spectra

AbstractCircularly polarised light (CPL) interacting with interstellar organic molecules might have imparted chiral bias and hence preluded prebiotic evolution of biomolecular homochirality. The l-enrichment of extra-terrestrial amino acids in meteorites, as opposed to no detectable excess in monocarboxylic acids and amines, has previously been attributed to their intrinsic interaction with stellar CPL revealed by substantial differences in their chiroptical signals. Recent analyses of meteoritic hydroxycarboxylic acids (HCAs) – potential co-building blocks of ancestral proto-peptides – indicated a chiral bias toward the l-enantiomer of lactic acid. Here we report on novel anisotropy spectra of several HCAs using a synchrotron radiation electronic circular dichroism spectrophotometer to support the re-evaluation of chiral biomarkers of extra-terrestrial origin in the context of absolute photochirogenesis. We found that irradiation by CPL which would yield l-excess in amino acids would also yield l-excess in aliphatic chain HCAs, including lactic acid and mandelic acid, in the examined conditions. Only tartaric acid would show “unnatural” d-enrichment, which makes it a suitable target compound for further assessing the relevance of the CPL scenario.

scholarly journals Lactate oxidative phosphorylation by annulus fibrosus cells: evidence for lactate-dependent metabolic symbiosis in intervertebral discs

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Dong Wang ◽  
Robert Hartman ◽  
Chao Han ◽  
Chao-ming Zhou ◽  
Brandon Couch ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Oxidative Phosphorylation ◽  
Intervertebral Disc ◽  
Annulus Fibrosus ◽  
Tca Cycle ◽  
Heavy Isotope ◽  
In Vivo Models ◽  
Disc Tissue ◽  
Tca Cycle Intermediates

Abstract Background Intervertebral disc degeneration contributes to low back pain. The avascular intervertebral disc consists of a central hypoxic nucleus pulpous (NP) surrounded by the more oxygenated annulus fibrosus (AF). Lactic acid, an abundant end-product of NP glycolysis, has long been viewed as a harmful waste that acidifies disc tissue and decreases cell viability and function. As lactic acid is readily converted into lactate in disc tissue, the objective of this study was to determine whether lactate could be used by AF cells as a carbon source rather than being removed from disc tissue as a waste byproduct. Methods Import and conversion of lactate to tricarboxylic acid (TCA) cycle intermediates and amino acids in rabbit AF cells were measured by heavy-isotope (13C-lactate) tracing experiments using mass spectrometry. Levels of protein expression of lactate converting enzymes, lactate importer and exporter in NP and AF tissues were quantified by Western blots. Effects of lactate on proteoglycan (35S-sulfate) and collagen (3H-proline) matrix protein synthesis and oxidative phosphorylation (Seahorse XFe96 Extracellular Flux Analyzer) in AF cells were assessed. Results Heavy-isotope tracing experiments revealed that AF cells imported and converted lactate into TCA cycle intermediates and amino acids using in vitro cell culture and in vivo models. Addition of exogenous lactate (4 mM) in culture media induced expression of the lactate importer MCT1 and increased oxygen consumption rate by 50%, mitochondrial ATP-linked respiration by 30%, and collagen synthesis by 50% in AF cell cultures grown under physiologic oxygen (2-5% O2) and glucose concentration (1-5 mM). AF tissue highly expresses MCT1, LDH-H, an enzyme that preferentially converts lactate to pyruvate, and PDH, an enzyme that converts pyruvate to acetyl-coA. In contrast, NP tissue highly expresses MCT4, a lactate exporter, and LDH-M, an enzyme that preferentially converts pyruvate to lactate. Conclusions These findings support disc lactate-dependent metabolic symbiosis in which lactate produced by the hypoxic, glycolytic NP cells is utilized by the more oxygenated AF cells via oxidative phosphorylation for energy and matrix production, thus shifting the current research paradigm of viewing disc lactate as a waste product to considering it as an important biofuel. These scientifically impactful results suggest novel therapeutic targets in disc metabolism and degeneration.

Determination of native amino acids and lactic acid inLactobacillus helveticusculture media by capillary electrophoresis using Cu2+and β-cyclodextrins as additives

2020 ◽  
Vol 1156 ◽  
pp. 122304 ◽  
Author(s):  
Daria Makeeva ◽  
Daria Polikarpova ◽  
Elena Demyanova ◽  
Evgeniia Roshchina ◽  
Timur Vakhitov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Capillary Electrophoresis ◽  
Lactic Acid

Measurement of Lactic Acid and Amino Acids in the Cerebral Cortex of Head-Injured Patients Using Microdialysis

1995 ◽  
pp. 78-83 ◽  
Author(s):  
J. Clay Goodman ◽  
Daniel P. Robertson ◽  
Shankar P. Gopinath ◽  
Raj K. Narayan ◽  
Robert G. Grossman ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cerebral Cortex ◽  
Lactic Acid ◽  
Head Injured ◽  
Injured Patients

Influence of thermophilic lactic acid bacteria strains on propionibacteria growth and lactate consumption in an Emmental juice-like medium

1999 ◽  
Vol 66 (1) ◽  
pp. 105-113 ◽  
Author(s):  
ANNE THIERRY ◽  
DELPHINE SALVAT-BRUNAUD ◽  
JEAN-LOUIS MAUBOIS
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acids ◽  
Free Amino ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
The Media ◽  
Lactate Consumption ◽  
Thermophilic Lactic Acid Bacteria

Swiss-type cheeses such as Emmental are characterized by the successive development of thermophilic lactic acid bacteria (TLAB) and propionibacteria. The aim of this study was to determine whether the choice of TLAB strain influenced propionibacteria. TLAB and propionibacteria were cultured sequentially under the conditions prevailing in cheese. Firstly, 11 Emmental juice-like media were prepared by fermenting casein-enriched milk with pure or mixed cultures of TLAB (Lactobacillus helveticus, Lb. delbrueckii subsp. lactis and Streptococcus thermophilus), differing in their proteolytic activities. TLAB cells were then removed by microfiltration. Finally, five strains of Propionibacterium freudenreichii were grown on these media at 24°C under anaerobiosis and their growth characteristics and lactate consumption determined. The media mainly differed in their contents of peptides (1·9–5·3 g/kg) and free amino acids (1·0–5·6 g/kg) and the proportions of lactate isomers (42–92% of the L(+) isomer). Propionibacteria were significantly (P<0·05) influenced by TLAB strains (differences in doubling times of up to 20% and differences in lactate consumption after 600 h culture of up to 52%). The influence of TLAB was similar for all the propionibacteria tested, depended on the TLAB strains and could not be generalized to the TLAB species. Propionibacteria were stimulated by high peptide levels, low levels of free amino acids and NaCl, a low proportion of L(+)-lactate and other undetermined factors. However, variations due to TLAB were less than those between propionibacteria strains.

Diversity in growth and protein degradation by dairy relevant lactic acid bacteria species in reconstituted whey

2012 ◽  
Vol 79 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Micaela Pescuma ◽  
Elvira M. Hébert ◽  
Elena Bru ◽  
Graciela Font de Valdez ◽  
Fernanda Mozzi
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Protein Degradation ◽  
Proteolytic Activity ◽  
Starter Culture ◽  
Whey Proteins ◽  
Principal Component ◽  
Fermented Foods ◽  
Small Peptides

The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37°C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, β-lactoglobulin, which was degraded the most byLactobacillus acidophilusCRL 636 andLb. delbrueckiisubsp.bulgaricusCRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.

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