scholarly journals Cystathionine γ-Lyase Is a Component of Cystine-Mediated Oxidative Defense in Lactobacillus reuteri BR11

2009 ◽  
Vol 191 (6) ◽  
pp. 1827-1837 ◽  
Author(s):  
Raquel Lo ◽  
Mark S. Turner ◽  
Daniel G. Barry ◽  
Revathy Sreekumar ◽  
Terence P. Walsh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Substrate Specificity ◽  
Abc Transporter ◽  
Lactobacillus Reuteri ◽  
Lag Phase ◽  
Cysteine Biosynthesis ◽  
High Concentration ◽  
Oxidative Defense ◽  
Growth Defects ◽  
Phase Arrest

ABSTRACT Lactobacillus reuteri BR11 possesses a novel mechanism of oxidative defense involving an abundant cystine ABC transporter encoded by the cyuABC gene cluster. Large amounts of thiols, including H2S, are secreted upon cystine uptake by the CyuC transporter. A cystathionine γ-lyase (cgl) gene is cotranscribed with the cyu genes in several L. reuteri strains and was hypothesized to participate in cystine-mediated oxidative defense by producing reducing equivalents. This hypothesis was tested with L. reuteri BR11 by constructing a cgl mutant (PNG901) and comparing it to a similarly constructed cyuC mutant (PNG902). Although Cgl was required for H2S production from cystine, it was not crucial for oxidative defense in de Mann-Rogosa-Sharpe medium, in contrast to CyuC, whose inactivation resulted in lag-phase arrest in aerated cultures. The importance of Cgl in oxidative defense was seen only in the presence of hemin, which poses severe oxidative stress. The growth defects in aerated cultures of both mutants were alleviated by supplementation with cysteine (and cystine in the cgl mutant) but not methionine, with the cyuC mutant showing a much higher concentration requirement. We conclude that L. reuteri BR11 requires a high concentration of exogenous cysteine/cystine to grow optimally under aerobic conditions. This requirement is fulfilled by the abundant CyuC transporter, which has probably arisen due to the broad substrate specificity of Cgl, resulting in a futile pathway which degrades cystine taken up by the CyuC transporter to H2S. Cgl plays a secondary role in oxidative defense by its well-documented function of cysteine biosynthesis.

scholarly journals Inactivation of an Iron Transporter in Lactococcus lactis Results in Resistance to Tellurite and Oxidative Stress

2007 ◽  
Vol 73 (19) ◽  
pp. 6144-6149 ◽  
Author(s):  
Mark S. Turner ◽  
Yu Pei Tan ◽  
Philip M. Giffard
Keyword(s):  
Oxidative Stress ◽  
Lactococcus Lactis ◽  
Oxygen Toxicity ◽  
Phosphate Transport ◽  
Lag Phase ◽  
Uptake System ◽  
Wild Type ◽  
Oxidative Defense ◽  
Genes Encoding ◽  
Resistant Mutants

ABSTRACT In Lactococcus lactis, the interactions between oxidative defense, metal metabolism, and respiratory metabolism are not fully understood. To provide an insight into these processes, we isolated and characterized mutants of L. lactis resistant to the oxidizing agent tellurite (TeO3 2−), which generates superoxide radicals intracellularly. A collection of tellurite-resistant mutants was obtained using random transposon mutagenesis of L. lactis. These contained insertions in genes encoding a proton-coupled Mn2+/Fe2+ transport homolog (mntH), the high-affinity phosphate transport system (pstABCDEF), a putative osmoprotectant uptake system (choQ), and a homolog of the oxidative defense regulator spx (trmA). The tellurite-resistant mutants all had better survival than the wild type following aerated growth. The mntH mutant was found to be impaired in Fe2+ uptake, suggesting that MntH is a Fe2+ transporter in L. lactis. This mutant is capable of carrying out respiration but does not generate as high a final pH and does not exhibit the long lag phase in the presence of hemin and oxygen that is characteristic of wild-type L. lactis. This study suggests that tellurite-resistant mutants also have increased resistance to oxidative stress and that intracellular Fe2+ can heighten tellurite and oxygen toxicity.

scholarly journals Hypoglycemic and antioxidative activities of ethanol seed extract of Hunteria umbellate (Hallier F.) on streptozotocin-induced diabetic rats

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Olubanke O. Ogunlana ◽  
Babatunde O. Adetuyi ◽  
Miracle Rotimi ◽  
lohor Esalomi ◽  
Alaba Adeyemi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Fasting Blood Glucose ◽  
Diabetic Rats ◽  
Seed Extract ◽  
The Body ◽  
High Concentration ◽  
Group 5

Abstract Background Diabetes, a global cause of mortality in developing countries is a chronic disorder affecting the metabolism of macromolecules and has been attributed to the defective production and action of insulin characterized by persistent hyperglycemic properties. This global disorder harms organs of the body such as the liver, kidney and spleen. Medicinal plants such as Hunteria umbellate have been shown to possess hypoglycemic, antioxidative and anti-diabetic properties owing to the high concentration of active phytochemical constituents like flavonoids and alkaloids. The present study seeks to evaluate the hypoglycemic activities of ethanolic seed extract of Hunteria umbellate on streptozotocin-induced diabetes rats. Methods Thirty (30) female experimental rats were randomly divided into five groups with six rats per group and were administered streptozotocin (STZ) and Hunteria umbellate as follows. Group 1 served as control and was given only distilled water, group 2 rats were administered 60 mg/kg STZ; Group 3 was administered 60 mg/kg STZ and 100 mg/kg metformin; group 4 rats were administered 60 mg/kg STZ and 800 mg/kg Hunteria umbellate, group 5 rats 60 mg/kg STZ and 400 mg/kg Hunteria umbellate. The fasting blood glucose level of each rat was measured before sacrifice. Rats were then sacrificed 24 h after the last dose of treatment. Results The results showed that Hunteria umbellate significantly reversed STZ-induced increase in fasting blood glucose and increase in body and organs weight of rats. Hunteria umbellate significantly reversed STZ-induced decrease in antioxidant enzyme in liver, kidney and spleen of rats. Hunteria umbellate significantly reversed STZ-induced increase in oxidative stress markers in liver, kidney and spleen of rats. Conclusion Collectively, our results provide convincing information that inhibition of oxidative stress and regulation of blood glucose level are major mechanisms through which Hunteria umbellate protects against streptozotocin-induced diabketes rats.

Kinetics of growth and multi substrate degradation by an indigenous mixed microbial culture isolated from a wastewater treatment plant in Guwahati, India

2008 ◽  
Vol 58 (5) ◽  
pp. 1101-1106
Author(s):  
Pichiah Saravanan ◽  
K. Pakshirajan ◽  
P. K. Saha
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Lag Phase ◽  
Microbial Culture ◽  
High Concentration ◽  
Mixed Microbial Culture ◽  
Phenol Biodegradation ◽  
Low Concentration ◽  
Culture Growth

An indigenous mixed culture of microorganisms, isolated from a sewage treatment plant, was investigated for its potential to simultaneously degrade phenol and m-cresol during its growth in batch shake flasks. 22 full factorial designs with the two substrates as the factors, at two different levels and two different initial concentration ranges, were employed to carry out the biodegradation experiments. For complete utilisation of phenol and m-cresol, the culture took a minimum duration of 21 hrs at their low concentration of 100 mg/L each, and a maximum duration of 187 hrs at high concentration of 600 mg/L each in the multisubstrate system. The biodegradation results also showed that the presence of phenol in low concentration range (100–300 mg/L did not inhibit m-cresol biodegradation; on the other hand, presence of m-cresol inhibited phenol biodegradation by the culture. Moreover, irrespective of the concentrations used, phenol was degraded preferentially and earlier than m-cresol. During the culture growth, a lag phase was observed above a combined concentration of 500 mg/L i.e., 200 mg/L m-cresol and 300 mg/L of phenol and above). Statistical analysis of the specific growth rate of the culture in the multisubstrate system was also performed in the form of ANOVA and Student ‘t’ test, which gave good interpretation in terms of main and interaction effects of the substrates.

scholarly journals Tubeimoside-1 induces oxidative stress-mediated apoptosis and G0/G1 phase arrest in human prostate carcinoma cells in vitro

2016 ◽  
Vol 37 (7) ◽  
pp. 950-962 ◽  
Author(s):  
Jing-bo Yang ◽  
Muhammad Khan ◽  
Yang-yang He ◽  
Min Yao ◽  
Yong-ming Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Prostate Carcinoma ◽  
Carcinoma Cells ◽  
Human Prostate ◽  
G1 Phase ◽  
Phase Arrest ◽  
G1 Phase Arrest ◽  
Human Prostate Carcinoma

scholarly journals Quantitative Analysis of Nutrients and Biochemical Evaluation in Pomfret Fish (Pampus argenteus) During Frozen Storage

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Utkalendu suvendusekhar Samantaray ◽  
Swagatika Tripathy
Keyword(s):  
Oxidative Stress ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Frozen Storage ◽  
Storage Condition ◽  
Essential Amino Acids ◽  
Omega 3 ◽  
High Concentration ◽  
Balanced Diet ◽  
Pampus Argenteus

Marine fish are well-known for being a high-quality protein source having high concentration of essential amino acids. It has high concentration of mono unsaturated and poly unsaturated fatty acids, which may aid in the optimization of lipid profiles and the reduction of the risk of coronary heart disease (CHD). The goal of this study was to estimate the nutritional and biochemical status of raw sea fish Pampus argenteus after 30 days of frozen storage at -200C with 15-day intervals. Nutrient study showed a decrease in protein and lipid content. The changes of hydrogen peroxide and oxidized lipid products were estimated in the muscle tissue during fresh and storage condition. Results indicate that during storage the oxidative stress increased. An antioxidant enzyme (superoxide dismutase, smutase, catalase, glutathione peroxidase) measurement was determined. The increased amount of oxidative stress during fish storage is shown by the differential activity of antioxidant enzymes. The amount of protein in fish varies slightly between species and even within species. Fish is high in protein, vitamins, minerals, and omega-3 fatty acids, which are essential for brain development (Spencer et al., 1971; Jacylin et al., 2010). A well-balanced diet consists variety of fish that can help in children's growth and development as well as their heart health (Jinadasa, 2014).

Angiotensin II-mediated biphasic regulation of proximal tubular Na+/H+ exchanger 3 is impaired during oxidative stress

2011 ◽  
Vol 301 (2) ◽  
pp. F364-F370 ◽  
Author(s):  
Anees Ahmad Banday ◽  
Mustafa F. Lokhandwala
Keyword(s):  
Oxidative Stress ◽  
Protein Kinase ◽  
Tap Water ◽  
Buthionine Sulfoximine ◽  
Inhibitory Effect ◽  
Ang Ii ◽  
Sprague Dawley ◽  
High Concentration ◽  
Nitric Oxide Signaling ◽  
Proximal Tubular

Angiotensin (ANG) II via AT1 receptors (AT1Rs) maintains sodium homeostasis by regulating renal sodium transporters including Na+/H+ exchanger 3 (NHE3) in a biphasic manner. Low-ANG II concentration stimulates whereas high concentrations inhibit NHE3 activity. Oxidative stress has been shown to upregulate AT1R function that could modulate the ANG II-mediated NHE3 regulation. This study was designed to identify the signaling pathways responsible for ANG II-mediated biphasic regulation of proximal tubular NHE3 and the effect of oxidative stress on this phenomenon. Male Sprague-Dawley rats were chronically treated with a pro-oxidant l-buthionine sulfoximine (BSO) with and without an antioxidant tempol in tap water for 3 wk. BSO-treated rats exhibited oxidative stress and high blood pressure. At low concentration (1 pM) ANG II increased NHE3 activity in proximal tubules from all animals. However, in BSO-treated rats, the stimulation was more robust and was normalized by tempol treatment. ANG II (1 pM)-mediated NHE3 activation was abolished by AT1R blocker, intracellular Ca2+ chelator, and inhibitors of phospholipase C (PLC) and Ca2+-dependent calmodulin (CaM) but it was insensitive to Giα and protein kinase C inhibitors or AT2R antagonist. A high concentration of ANG II (1 μM) inhibited NHE3 activity in control and tempol-treated rats. However, in BSO-treated rats, ANG II (1 μM) continued to induce NHE3 stimulation. Tempol restored the inhibitory effect of ANG II (1 μM) in BSO-treated rats. The inhibitory effect of ANG II (1 μM) involved AT1R-dependent, cGMP-dependent protein kinase (PKG) activation and was independent of AT2 receptor and nitric oxide signaling. We conclude that ANG II stimulates NHE3 via AT1R-PLC-CaM pathway and inhibits NHE3 by AT1R-PKG activation. Oxidative stress impaired ANG II-mediated NHE3 biphasic response in that stimulation was observed at both high- and low-ANG II concentration.

scholarly journals Characterization of the Efflux Capability and Substrate Specificity of Aspergillus fumigatus PDR5-like ABC Transporters Expressed in Saccharomyces cerevisiae

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Brooke D. Esquivel ◽  
Jeffrey M. Rybak ◽  
Katherine S. Barker ◽  
Jarrod R. Fortwendel ◽  
P. David Rogers ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Drug Resistance ◽  
Substrate Specificity ◽  
Abc Transporter ◽  
Drug Susceptibility ◽  
Antifungal Drugs ◽  
Efflux Transporters ◽  
Content Type ◽  
Background Strain

ABSTRACT This research analyzed six Aspergillus fumigatus genes encoding putative efflux proteins for their roles as transporters. The A. fumigatus genes abcA, abcC, abcF, abcG, abcH, and abcI were cloned into plasmids and overexpressed in a Saccharomyces cerevisiae strain in which the highly active endogenous ABC transporter gene PDR5 was deleted. The activity of each transporter was measured by efflux of rhodamine 6G and accumulation of alanine β-naphthylamide. The transporters AbcA, AbcC, and AbcF had the strongest efflux activities of these compounds. All of the strains with plasmid-expressed transporters had more efflux activity than did the PDR5-deleted background strain. We performed broth microdilution drug susceptibility testing and agar spot assays using an array of compounds and antifungal drugs to determine the transporter specificity and drug susceptibility of the strains. The transporters AbcC and AbcF showed the broadest range of substrate specificity, while AbcG and AbcH had the narrowest range of substrates. Strains expressing the AbcA, AbcC, AbcF, or AbcI transporter were more resistant to fluconazole than was the PDR5-deleted background strain. Strains expressing AbcC and AbcF were additionally more resistant to clotrimazole, itraconazole, ketoconazole, and posaconazole than was the background strain. Finally, we analyzed the expression levels of the genes by reverse transcription-quantitative PCR (RT-qPCR) in triazole-susceptible and -resistant A. fumigatus clinical isolates. All of these transporters are expressed at a measurable level, and transporter expression varied significantly between strains, demonstrating the high degree of phenotypic variation, plasticity, and divergence of which this species is capable. IMPORTANCE One mechanism behind drug resistance is altered export out of the cell. This work is a multifaceted analysis of membrane efflux transporters in the human fungal pathogen A. fumigatus. Bioinformatics evidence infers that there is a relatively large number of genes in A. fumigatus that encode ABC efflux transporters. However, very few of these transporters have been directly characterized and analyzed for their potential role in drug resistance. Our objective was to determine if these undercharacterized proteins function as efflux transporters and then to better define whether their efflux substrates include antifungal drugs used to treat fungal infections. We chose six A. fumigatus potential plasma membrane ABC transporter genes for analysis and found that all six genes produced functional transporter proteins. We used two fungal systems to look for correlations between transporter function and drug resistance. These transporters have the potential to produce drug-resistant phenotypes in A. fumigatus. Continued characterization of these and other transporters may assist in the development of efflux inhibitor drugs.

scholarly journals Antioxidant Effect of the Castanea sativa Mill. Leaf Extract on Oxidative Stress Induced upon Human Spermatozoa

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Marco Biagi ◽  
Daria Noto ◽  
Maddalena Corsini ◽  
Giulia Baini ◽  
Daniela Cerretani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Sperm Motility ◽  
Leaf Extract ◽  
Colorimetric Assay ◽  
Castanea Sativa ◽  
High Concentration ◽  
Tem Analysis ◽  
Dpph Test

This study was aimed at evaluating in vitro the effects of a 75% v/v ethanolic extract of leaves of Castanea sativa Mill. (var. Bastarda Rossa, Mount Amiata, Tuscany, Italy) on ejaculated human sperm. Total polyphenols and total flavonoids contained in the extract were determined by a colorimetric assay and HPLC-DAD. The DPPH test and electrochemistry were utilized to study the antioxidant activity of the extract. Swim-up-selected sperm from 8 healthy men were treated with the C. sativa leaf extract at different dilutions (1 : 100, 1 : 200, and 1 : 500), and sperm motility was assessed following the WHO guidelines. Swim-up-selected spermatozoa were incubated with 100 μM H2O2 to induce lipid peroxidation (LPO) and with H2O2 and the leaf extract (1 : 100, 1 : 200, and 1 : 500) to test the antioxidant activity of the extract. The levels of LPO were determined by measuring malondialdehyde (MDA) concentrations. The treated samples were also analyzed by transmission electron microscopy (TEM) for ultrastructural evaluation. The chemical analysis showed that one-third ca. of the polyphenols in the C. sativa extract were made up of flavonoids, with hyperoside present in high concentration. A good antioxidant activity was demonstrated by both the DPPH test and electrochemical analysis. The C. sativa leaf extract did not decrease sperm motility at all tested dilutions. Treatment with H2O2 alone caused a significant increment in MDA levels (P=0.006993), while the treatment with H2O2 plus C. sativa extract diluted to 1 : 100 and 1 : 200 significantly reduced MDA levels (P=0.01476 and P=0.01571, respectively), with respect to H2O2 alone. TEM analysis confirmed the protective effect of the extract on damage induced by LPO, in particular that occurring at the plasma membrane level. The C. sativa leaf extract could be used in human and farm animal protocols for gamete handling, such as techniques of assisted reproduction and cryopreservation of semen, all conditions in which oxidative stress is exacerbated.

scholarly journals Polyphenols by Generating H2O2, Affect Cell Redox Signaling, Inhibit PTPs and Activate Nrf2 Axis for Adaptation and Cell Surviving: In Vitro, In Vivo and Human Health

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 797 ◽  
Author(s):  
Joseph Kanner
Keyword(s):  
Oxidative Stress ◽  
Gastrointestinal Tract ◽  
Human Health ◽  
Blood System ◽  
Cytotoxic Agents ◽  
Related Factor ◽  
High Concentration ◽  
Oxidation Stress ◽  
End Products

Human health benefits from different polyphenols molecules consumption in the diet, derived mainly by their common activities in the gastrointestinal tract and at the level of blood micro-capillary. In the stomach, intestine and colon, polyphenols act as reducing agents preventing lipid peroxidation, generation and absorption of AGEs/ALEs (advanced glycation end products/advanced lipid oxidation end products) and postprandial oxidative stress. The low absorption of polyphenols in blood does not support their activity as antioxidants and their mechanism of activity is not fully understood. The results are from in vitro, animal and human studies, detected by relevant oxidative stress markers. The review carries evidences that polyphenols, by generating H2O2 at nM concentration, exogenous to cells and organs, act as activators of signaling factors increasing cell Eustress. When polyphenols attain high concentration in the blood system, they generate H2O2 at µM concentration, acting as cytotoxic agents and Distress. Pre-treatment of cells or organisms with polyphenols, by generating H2O2 at low levels, inhibits cellular PTPs (protein tyrosine phosphatases), inducing cell signaling through transcription of the Nrf2 (nuclear factor erythroid 2-related factor 2) axis of adaptation and protection to oxidation stress. Polyphenols ingestion at the right amount and time during the meal acts synergistically at the level of the gastrointestinal tract (GIT) and blood system, for keeping the redox homeostasis in our organism and better balancing human health.

Effect of 6 Weeks of n-3 Fatty-Acid Supplementation on Oxidative Stress in Judo Athletes

2010 ◽  
Vol 20 (6) ◽  
pp. 496-506 ◽  
Author(s):  
Edith Filaire ◽  
Alain Massart ◽  
Hugues Portier ◽  
Matthieu Rouveix ◽  
Fatima Rosado ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Significant Interaction ◽  
Training Session ◽  
Interaction Effects ◽  
Lag Phase ◽  
Significant Interaction Effect ◽  
Chain Pufa ◽  
Dietary Record ◽  
Before And After ◽  
Exercise Induced

The aim of this investigation was to assess the effects of 6 wk of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) supplementation on resting and exercise-induced lipid peroxidation and antioxidant status in judoists. Subjects were randomly assigned to receive a placebo or a capsule of polyunsaturated fatty acids (PUFAs; 600 mg EPA and 400 mg DHA). Blood samples were collected in preexercise and postexercise conditions (judo-training session), both before and after the supplementation period. The following parameters were analyzed: α-tocopherol, retinol, lag phase, maximum rate of oxidation (Rmax) during the propagating chain reaction, maximum amount of conjugated dienes (CDmax) accumulated after the propagation phase, nitric oxide (NO) and malondyaldehide (MDA) concentrations, salivary glutathione peroxidase activity, and the lipid profile. Dietary data were collected using a 7-day dietary record. A significant interaction effect between supplementation and time (p < .01) on triglycerides was noted, with values significantly lower in the n-3 long-chain-PUFA (LCPUFA) group after supplementation than in the placebo group. Significant interaction effects between supplementation and time on resting MDA concentrations and Rmax were found (p = .03 and p = .04, respectively), with elevated values in the n-3 LCPUFA group after supplementation and no change in the placebo group’s levels. The authors observed a significantly greater NO and oxidative-stress increase with exercise (MDA, Rmax, CDmax, and NO) in the n-3 LCPUFA group than with placebo. No main or interaction effects were found for retinol and α-tocopherol. These results indicate that supplementation with n-3 LCPUFAs significantly increased oxidative stress at rest and after a judo-training session.

Sign in / Sign up

Export Citation Format

Share Document