scholarly journals Metabolic Profiling of Xylooligosaccharides by Lactobacilli

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2387
Author(s):  
Ilia Iliev ◽  
Tonka Vasileva ◽  
Veselin Bivolarski ◽  
Albena Momchilova ◽  
Iskra Ivanova
Keyword(s):  
Plasma Membranes ◽  
Meat Products ◽  
Lactobacillus Brevis ◽  
Degree Of Polymerization ◽  
Acid Fermentation ◽  
Carbohydrate Utilization ◽  
Beneficial Effects ◽  
Mixed Acid ◽  
Rat Liver Plasma Membranes ◽  
Different Types

Three lactic acid bacteria (LAB) strains identified as Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus sakei isolated from meat products were tested for their ability to utilize and grow on xylooligosaccharides (XOSs). The extent of carbohydrate utilization by the studied strains was analyzed by HPLC. All three strains showed preferences for the degree of polymerization (DP). The added oligosaccharides induced the LAB to form end-products of typical mixed-acid fermentation. The utilization of XOSs by the microorganisms requires the action of three important enzymes: β-xylosidase (EC 3.2.1.37) exo-oligoxylanase (EC 3.2.1.156) and α-L-arabinofuranosidase (EC 3.2.1.55). The presence of intracellular β-D-xylosidase in Lb. brevis, Lb. plantarum, and Lb. sakei suggest that XOSs might be the first imported into the cell by oligosaccharide transporters, followed by their degradation to xylose. The studies on the influence of XOS intake on the lipids of rat liver plasma membranes showed that oligosaccharides display various beneficial effects for the host organism, which are probably specific for each type of prebiotic used. The utilization of different types of oligosaccharides may help to explain the ability of Lactobacillus strains to compete with other bacteria in the ecosystem of the human gastrointestinal tract.

Altered Superoxide Dismutase Activity by Carbohydrate Utilization in a Lactococcus lactis Strain

2014 ◽  
Vol 77 (7) ◽  
pp. 1161-1167 ◽  
Author(s):  
H. KIMOTO-NIRA ◽  
N. MORIYA ◽  
H. OHMORI ◽  
C. SUZUKI
Keyword(s):  
Superoxide Dismutase ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Nadh Oxidase ◽  
Acid Fermentation ◽  
Sod Activity ◽  
Carbohydrate Utilization ◽  
Carbohydrate Source ◽  
Mixed Acid Fermentation ◽  
Mixed Acid

Reactive oxygen species, such as superoxide, can damage cellular components, such as proteins, lipids, and DNA. Superoxide dismutase (SOD) enzymes catalyze the conversion of superoxide anions to hydrogen peroxide and dioxygen. SOD is present in most lactococcal bacteria, which are commonly used as starters for manufacturing fermented dairy products and may have health benefits when taken orally. We assessed the effects of carbohydrate use on SOD activity in lactococci. In Lactococcus lactis ssp. lactis G50, the SOD activity of cells grown on lactose and galactose was higher than that on glucose; in Lactococcus lactis ssp. cremoris H61, SOD activity was independent of the type of carbohydrate used. We also investigated the activity of NADH oxidase, which is related to the production of superoxide in strains G50 and H61. Activity was highest in G50 cells grown on lactose, lower on galactose, and lowest on glucose, whereas activity in H61 cells did not differ with the carbohydrate source used. The SOD and NADH oxidase activities of strain G50 in three carbohydrates were linked. Strain G50 fermented lactose and galactose to lactate, acetate, formate, and ethanol (mixed-acid fermentation) and fermented glucose to mainly lactate (homolactic fermentation). Strain H61 fermented glucose, lactose, and galactose to mainly lactate (homolactic fermentation). In strain G50, when growth efficiency was reduced by adding a metabolic inhibitor to the growth medium, SOD activity was higher than in the control; however, the metabolism was homofermentative. Aerobic conditions, but not glucose-limited conditions, increased SOD activity, and mixed-acid fermentation occurred. We conclude that the effect of carbohydrate on SOD activity in lactococci is strain dependent and that the activity of commercial lactococci can be enhanced through carbohydrate selection for mixed-acid fermentation or by changing the energy distribution, thus enhancing the value of the starter and the resulting dairy products.

Are Improvements in Assessment Center Construct-Related Validity Paralleled by Improvements in Criterion-Related Validity?

2014 ◽  
Vol 13 (4) ◽  
pp. 184-193 ◽  
Author(s):  
Andreja Wirz ◽  
Klaus G. Melchers ◽  
Stefan Schultheiss ◽  
Martin Kleinmann
Keyword(s):  
Convergent Validity ◽  
Study Data ◽  
Assessment Center ◽  
Beneficial Effects ◽  
Single Study ◽  
Different Types

Previous studies have found that factors that improved assessment center (AC) construct-related validity also had beneficial effects on criterion-related validity. However, some factors might have diverging effects on construct- and criterion-related validity. Accordingly, we followed recent calls to evaluate construct- and criterion-related validity of ACs simultaneously by examining the effects of exercise similarity on both aspects of validity within a single study. Data were collected in an AC (N = 92) that consisted of two different types of exercises. Convergent validity was better for similar exercises than it was for dissimilar exercises. However, regarding criterion-related validity, we did not find differences between similar and dissimilar exercises. Hence, this study revealed that improvements in AC construct-related validity are not necessarily paralleled by improvements in criterion-related validity.

Creation of Plasmidless and Markerless Escherichia coli Succinate Producing Strain and Evaluation of its Biosynthetic Potential during Utilization of Lignocellulosic Sugars

2020 ◽  
Vol 36 (2) ◽  
pp. 3-11
Author(s):  
O.A. Zhuravliova ◽  
Т.А. Voeikova ◽  
A.Yu. Gulevich ◽  
V.G. Debabov
Keyword(s):  
Escherichia Coli ◽  
Succinic Acid ◽  
Plant Biomass ◽  
Anaerobic Fermentation ◽  
Basic Research ◽  
Acid Fermentation ◽  
Mixed Acid ◽  
Gene Coding ◽  
Lignocellulosic Sugars ◽  
Basic Research Project

The plasmidless and markerless Escherichia coli succinate producing strain SGM2.0Pyc-int has been engineered and characterized. The strain has the inactivated main mixed-acid fermentation pathways due to the deletions of ldhA,poxB, ackA,pta, and adhE genes, constitutively expresses the genes of the aceEF-lpdA operon encoding components of pyravate dehydrogenase complex, and possesses the chromosomally integrated Bacillus subtilis pycA gene coding for pyruvate carboxylase. The capacity of the strain to synthesize succinic acid in course of dual-phase aerobic-anaerobic fermentation with lignocellulosic sugars as substrates was studied. The SGM2.0Pyc-int strain synthesized succinic acid from glucose, xylose, and arabinose with a molar yields of 1.41 mol/mol, 1.18 mol/mol, and 1.18 mol/mol, respectively, during the anaerobic production stage. The constructed strain has great potential for developing efficient processes for the succinic acid production from plant biomass-derived sugars. Escherichia coli, fermentation, arabinose, glucose, xylose, succinic acid. The work was supported by a Grant from the Russian Foundation for Basic Research (Project no. 18-29-14005).

scholarly journals Stem cells and exosomes: promising candidates for necrotizing enterocolitis therapy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruijie Zeng ◽  
Jinghua Wang ◽  
Zewei Zhuo ◽  
Yujun Luo ◽  
Weihong Sha ◽  
...  
Keyword(s):  
Stem Cells ◽  
Necrotizing Enterocolitis ◽  
Therapeutic Effects ◽  
Beneficial Effects ◽  
Pediatric Diseases ◽  
Gastrointestinal Conditions ◽  
Different Types ◽  
Novel Therapeutic Strategies

AbstractNecrotizing enterocolitis (NEC) is a devastating disease predominately affecting neonates. Despite therapeutic advances, NEC remains the leading cause of mortality due to gastrointestinal conditions in neonates. Stem cells have been exploited in various diseases, and the application of different types of stem cells in the NEC therapy is explored in the past decade. However, stem cell transplantation possesses several deficiencies, and exosomes are considered potent alternatives. Exosomes, especially those derived from stem cells and breast milk, demonstrate beneficial effects for NEC both in vivo and in vitro and emerge as promising options for clinical practice. In this review, the function and therapeutic effects of stem cells and exosomes for NEC are investigated and summarized, which provide insights for the development and application of novel therapeutic strategies in pediatric diseases. Further elucidation of mechanisms, improvement in preparation, bioengineering, and administration, as well as rigorous clinical trials are warranted.

scholarly journals Lysophosphatidylcholines can modulate the activity of the glucagon-stimulated adenylate cyclase from rat liver plasma membranes

1979 ◽  
Vol 178 (1) ◽  
pp. 217-221 ◽  
Author(s):  
M D Houslay ◽  
R W Palmer
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Increased Sensitivity

1. Synthetic lysophosphatidylcholines inhibit the glucagon-stimulated adenylate cyclase activity of rat liver plasma membranes at concentrations two to five times lower than those needed to inhibit the fluoride-stimulated activity. 2. Specific 125I-labelled glucagon binding to hormone receptors is inhibited at concentrations similar to those inhibiting the fluoride-stimulated activity. 3. At concentrations of lysophosphatidylcholines immediately below those causing inhibition, an activation of adenylate cyclase activity or hormone binding was observed. 4 These effects are essentially reversible. 5. We conclude that the increased sensitivity of glucagon-stimulated adenylate cyclase to inhibition may be due to the lysophosphatidylcholines interfering with the physical coupling between the hormone receptor and catalytic unit of adenylate cyclase. 6. We suggest that, in vivo, it is possible that lysophosphatidylcholines may modulate the activity of adenylate cyclase only when it is in the hormone-stimulated state.

scholarly journals The roles of phospholipase D and a GTP-binding protein in guanosine 5′-[γ-thio]triphosphate-stimulated hydrolysis of phosphatidylcholine in rat liver plasma membranes

1990 ◽  
Vol 272 (3) ◽  
pp. 749-753 ◽  
Author(s):  
K M Hurst ◽  
B P Hughes ◽  
G J Barritt
Keyword(s):  
Rat Liver ◽  
Phospholipase D ◽  
Plasma Membranes ◽  
Regulatory Protein ◽  
Gtp Binding ◽  
Liver Plasma Membranes ◽  
Low Concentrations ◽  
Rat Liver Plasma Membranes ◽  
Triton X ◽  
Hydrolysis Of

1. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]) stimulated by 50% the rate of release of [3H]choline and [3H]phosphorylcholine in rat liver plasma membranes labelled with [3H]choline. About 70% of the radioactivity released in the presence of GTP[S] was [3H]choline and 30% was [3H]phosphorylcholine. 2. The hydrolysis of phosphorylcholine to choline and the conversion of choline to phosphorylcholine did not contribute to the formation of [3H]choline and [3H]phosphorylcholine respectively. 3. The release of [3H]choline from membranes was inhibited by low concentrations of SDS or Triton X-100. Considerably higher concentrations of the detergents were required to inhibit the release of [3H]phosphorylcholine. 4. Guanosine 5′-[beta gamma-imido]triphosphate and guanosine 5′-[alpha beta-methylene]triphosphate, but not adenosine 5′-[gamma-thio]-triphosphate, stimulated [3H]choline release to the same extent as did GTP[S]. The GTP[S]-stimulated [3H]choline release was inhibited by guanosine 5′-[beta-thio]diphosphate, GDP and GTP but not by GMP. 5. It is concluded that, in rat liver plasma membranes, (a) GTP[S]-stimulated hydrolysis of phosphatidylcholine is catalysed predominantly by phospholipase D with some contribution from phospholipase C, and (b) the stimulation of phosphatidylcholine hydrolysis by GTP[s] occurs via a GTP-binding regulatory protein.

Receptors for calcitonin gene-related peptide on the rat liver plasma membranes

1988 ◽  
Vol 152 (1) ◽  
pp. 383-391 ◽  
Author(s):  
Akinori Yamaguchi ◽  
Tsutomu Chiba ◽  
Yasuhiko Okimura ◽  
Toshiyuki Yamatani ◽  
Tomoyuki Morishita ◽  
...  
Keyword(s):  
Rat Liver ◽  
Plasma Membranes ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Liver Plasma Membranes ◽  
Calcitonin Gene ◽  
Rat Liver Plasma Membranes
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