scholarly journals Queuine is a nutritional regulator of Entamoeba histolytica response to oxidative stress and a virulence attenuator

2020 ◽  
Author(s):  
Shruti Nagaraja ◽  
Maggi W. Cai ◽  
Jingjing Sun ◽  
Hugo Varet ◽  
Lotem Sarid ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Entamoeba Histolytica ◽  
Cysteine Proteases ◽  
Small Gtpases ◽  
Cytoskeletal Proteins ◽  
Transfer Rnas ◽  
Amebic Dysentery ◽  
Naturally Occurring ◽  
Expression Of Genes ◽  
Negative Effect

Queuosine is a naturally occurring modified ribonucleoside found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His and Tyr. Eukaryotes lack pathways to synthesize queuine, the nucleobase precursor to queuosine, and must obtain it from diet or gut microbiota. Here we describe the effects of queuine on the physiology of the eukaryotic parasite, Entamoeba histolytica, the causative agent of amebic dysentery. Queuine is efficiently incorporated into E. histolytica tRNAs by a tRNA-guanine transglycosylase (EhTGT) and this incorporation stimulates the methylation of C38 in tRNAAspGUC. Queuine protects the parasite against oxidative stress (OS) and antagonizes the negative effect that oxidation has on translation by inducing the expression of genes involved in OS response, such as heat shock protein 70 (Hsp 70), antioxidant enzymes, and enzymes involved in DNA repair. On the other hand, queuine impairs E. histolytica virulence by downregulating the expression of genes previously associated with virulence, including cysteine proteases, cytoskeletal proteins, and small GTPases. Silencing of EhTGT prevents incorporation of queuine into tRNAs and strongly impairs methylation of C38 in tRNAAspGUC, parasite growth, resistance to OS, and cytopathic activity. Overall, our data reveal that queuine plays a dual role in promoting OS resistance and reducing parasite virulence.

scholarly journals Queuine Is a Nutritional Regulator of Entamoeba histolytica Response to Oxidative Stress and a Virulence Attenuator

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Shruti Nagaraja ◽  
Maggi W. Cai ◽  
Jingjing Sun ◽  
Hugo Varet ◽  
Lotem Sarid ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Entamoeba Histolytica ◽  
Cysteine Proteases ◽  
Small Gtpases ◽  
Cytoskeletal Proteins ◽  
Content Type ◽  
Transfer Rnas ◽  
Amebic Dysentery ◽  
Expression Of Genes ◽  
Negative Effect

ABSTRACT Queuosine is a naturally occurring modified ribonucleoside found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His, and Tyr. Eukaryotes lack pathways to synthesize queuine, the nucleobase precursor to queuosine, and must obtain it from diet or gut microbiota. Here, we describe the effects of queuine on the physiology of the eukaryotic parasite Entamoeba histolytica, the causative agent of amebic dysentery. Queuine is efficiently incorporated into E. histolytica tRNAs by a tRNA-guanine transglycosylase (EhTGT) and this incorporation stimulates the methylation of C38 in tRNAGUCAsp. Queuine protects the parasite against oxidative stress (OS) and antagonizes the negative effect that oxidation has on translation by inducing the expression of genes involved in the OS response, such as heat shock protein 70 (Hsp70), antioxidant enzymes, and enzymes involved in DNA repair. On the other hand, queuine impairs E. histolytica virulence by downregulating the expression of genes previously associated with virulence, including cysteine proteases, cytoskeletal proteins, and small GTPases. Silencing of EhTGT prevents incorporation of queuine into tRNAs and strongly impairs methylation of C38 in tRNAGUCAsp, parasite growth, resistance to OS, and cytopathic activity. Overall, our data reveal that queuine plays a dual role in promoting OS resistance and reducing parasite virulence. IMPORTANCE Entamoeba histolytica is a unicellular parasite that causes amebiasis. The parasite resides in the colon and feeds on the colonic microbiota. The gut flora is implicated in the onset of symptomatic amebiasis due to alterations in the composition of bacteria. These bacteria modulate the physiology of the parasite and affect the virulence of the parasite through unknown mechanisms. Queuine, a modified nucleobase of queuosine, is exclusively produced by the gut bacteria and leads to tRNA modification at the anticodon loops of specific tRNAs. We found that queuine induces mild oxidative stress resistance in the parasite and attenuates its virulence. Our study highlights the importance of bacterially derived products in shaping the physiology of the parasite. The fact that queuine inhibits the virulence of E. histolytica may lead to new strategies for preventing and/or treating amebiasis by providing to the host queuine directly or via probiotics.

scholarly journals Erythrocytes Prevent Degradation of Carnosine by Human Serum Carnosinase

2021 ◽  
Vol 22 (23) ◽  
pp. 12802
Author(s):  
Henry Oppermann ◽  
Stefanie Elsel ◽  
Claudia Birkemeyer ◽  
Jürgen Meixensberger ◽  
Frank Gaunitz
Keyword(s):  
Oxidative Stress ◽  
Human Serum ◽  
Food Supplement ◽  
Aging Effects ◽  
Atp Production ◽  
Beneficial Effects ◽  
Naturally Occurring ◽  
Negative Effect ◽  
Improve Exercise Performance ◽  
First Time

The naturally occurring dipeptide carnosine (β-alanyl-l-histidine) has beneficial effects in different diseases. It is also frequently used as a food supplement to improve exercise performance and because of its anti-aging effects. Nevertheless, after oral ingestion, the dipeptide is not detectable in human serum because of rapid degradation by serum carnosinase. At the same time, intact carnosine is excreted in urine up to five hours after intake. Therefore, an unknown compartment protecting the dipeptide from degradation has long been hypothesized. Considering that erythrocytes may constitute this compartment, we investigated the uptake and intracellular amounts of carnosine in human erythrocytes cultivated in the presence of the dipeptide and human serum using liquid chromatography–mass spectrometry. In addition, we studied carnosine’s effect on ATP production in red blood cells and on their response to oxidative stress. Our experiments revealed uptake of carnosine into erythrocytes and protection from carnosinase degradation. In addition, no negative effect on ATP production or defense against oxidative stress was observed. In conclusion, our results for the first time demonstrate that erythrocytes can take up carnosine, and, most importantly, thereby prevent its degradation by human serum carnosinase.

scholarly journals Probing the Peculiarity of EhRabX10, a pseudoRab GTPase, from the Enteric Parasite Entamoeba histolytica through In Silico Modeling and Docking Studies

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mrinalini Roy ◽  
Sanket Kaushik ◽  
Anupam Jyoti ◽  
Vijay Kumar Srivastava
Keyword(s):  
Entamoeba Histolytica ◽  
In Silico ◽  
Secretory Pathway ◽  
3D Structure ◽  
Cysteine Proteases ◽  
Physicochemical Analysis ◽  
Small Gtpases ◽  
Host Cells ◽  
Rab Gtpases ◽  
Tissue Invasion

Entamoeba histolytica (Eh) is a pathogenic eukaryote that often resides silently in humans under asymptomatic stages. Upon indeterminate stimulus, it develops into fulminant amoebiasis that causes severe hepatic abscesses with 50% mortality. This neglected tropical pathogen relies massively on membrane modulation to flourish and cause disease; these modulations range from the phagocytic mode for food acquisition to a complex trogocytosis mechanism for tissue invasion. Rab GTPases form the largest branch of the Ras-like small GTPases, with a diverse set of roles across the eukaryotic kingdom. Rab GTPases are vital for the orchestration of membrane transport and the secretory pathway responsible for transporting the pathogenic effectors, such as cysteine proteases (EhCPs) which help in tissue invasion. Rab GTPases thus play a crucial role in executing the cytolytic effect of E. histolytica. First, they interact with Gal/Nac lectins required for adhering to the host cells, and then, they assist in the secretion of EhCPs. Additionally, amoebic Rab GTPases are vital for encystation because substantial vesicular trafficking is required to create dormant amoebic cysts. These cysts are the infective agent and help to spread the disease. The absence of a “bonafide” vesicular transport machinery in Eh and the existence of a diverse repertoire of amoebic Rab GTPases (EhRab) hint at their contribution in supporting this atypical machinery. Here, we provide insights into a pseudoRab GTPase, EhRabX10, by performing physicochemical analysis, predictive 3D structure modeling, protein-protein interaction studies, and in silico molecular docking. Our group is the first one to classify EhRabX10 as a pseudoRab GTPase with four nonconserved G-motifs. It possesses the basic fold of the P-loop containing nucleotide hydrolases. Through this in silico study, we provide an introduction to the characterization of the atypical EhRabX10 and set the stage for future explorations into the mechanisms of nucleotide recognition, binding, and hydrolysis employed by the pseudoEhRab GTPase family.

scholarly journals The Dichloromethane Fraction of Croton sonorae, A Plant Used in Sonoran Traditional Medicine, Affect Entamoeba histolytica Erythrophagocytosis and Gene Expression

2021 ◽  
Vol 11 ◽  
Author(s):  
Isaac Villegas-Gómez ◽  
Angélica Silva-Olivares ◽  
Ramón Enrique Robles-Zepeda ◽  
Juan-Carlos Gálvez-Ruiz ◽  
Mineko Shibayama ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Intestinal Parasites ◽  
Gastrointestinal Symptoms ◽  
Treatment Strategies ◽  
Cysteine Proteases ◽  
Potential Source ◽  
Expression Of Genes ◽  
Erythrocyte Adhesion ◽  
Antiamoebic Activity ◽  
New Treatment

Intestinal parasites are a global problem, mainly in developing countries. Obtaining information about plants and compounds that can combat gastrointestinal disorders and gastrointestinal symptoms is a fundamental first step in designing new treatment strategies. In this study, we analyzed the antiamoebic activity of the aerial part of Croton sonorae. The dichloromethane fraction of C. sonorae (CsDCMfx) contained flavonoids, terpenes, alkaloids, and glycosides. The ultrastructural morphology of the amoebae treated for 72 h with CsDCMfx was completely abnormal. CsDCMfx reduced erythrophagocytosis of trophozoites and the expression of genes involved in erythrocyte adhesion (gal/galnac lectin) and actin cytoskeleton rearrangement in the phagocytosis pathway (rho1 gtpase and formin1). Interestingly, CsDCMfx decreased the expression of genes involved in Entamoeba histolytica trophozoite pathogenesis, such as cysteine proteases (cp1, cp4, and cp5), sod, pfor, and enolase. These results showed that C. sonorae is a potential source of antiamoebic compounds.

The mechanisms involved in obesity-induced male infertility

2020 ◽  
Vol 16 ◽  
Author(s):  
Hamed Heydari ◽  
Rafighe Ghiasi ◽  
Saber Ghaderpour ◽  
Rana Keyhanmanesh
Keyword(s):  
Oxidative Stress ◽  
Metabolic Disease ◽  
Male Infertility ◽  
Male Fertility ◽  
Reproductive Function ◽  
Disease Development ◽  
Significant Evidence ◽  
Male Reproductive Function ◽  
Negative Effect ◽  
And Oxidative Stress

Introduction: Obesity resulted by imbalance between the intake of energy and energy consumption can lead to growth and metabolic disease development in people. Both in obese men and animal models, several studies indicate that obesity leads to male infertility. Objective: This review has discussed some mechanisms involved in obesity-induced male infertility. Method: Online documents were searched through Science Direct, Pubmed, Scopus, and Google Scholar websites dating from 1959 to recognize studies on obesity, kisspeptin, leptin, and infertility. Results: Obesity induced elevated inflammatory cytokines and oxidative stress can affect male reproductive functions including spermatogenesis disorders, reduced male fertility power and hormones involved in hypothalamus-pituitarygonadal axis. Conclusion: There is significant evidence that obesity resulted in male infertility. obesity has negative effect on male reproductive function via several mechanisms such as inflammation and oxidative stress.

scholarly journals The Negative Effect of Protein Phosphatase Z1 Deletion on the Oxidative Stress Tolerance of Candida albicans Is Synergistic with Betamethasone Exposure

2021 ◽  
Vol 7 (7) ◽  
pp. 540
Author(s):  
Ágnes Jakab ◽  
Tamás Emri ◽  
Kinga Csillag ◽  
Anita Szabó ◽  
Fruzsina Nagy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Candida Albicans ◽  
Protein Phosphatase ◽  
Combined Treatment ◽  
Specific Protein ◽  
Ergosterol Biosynthesis ◽  
Acid Oxidation ◽  
Menadione Sodium Bisulfite ◽  
Rnaseq Data ◽  
Negative Effect

The glucocorticoid betamethasone (BM) has potent anti-inflammatory and immunosuppressive effects; however, it increases the susceptibility of patients to superficial Candida infections. Previously we found that this disadvantageous side effect can be counteracted by menadione sodium bisulfite (MSB) induced oxidative stress treatment. The fungus specific protein phosphatase Z1 (CaPpz1) has a pivotal role in oxidative stress response of Candida albicans and was proposed as a potential antifungal drug target. The aim of this study was to investigate the combined effects of CaPPZ1 gene deletion and MSB treatment in BM pre-treated C. albicans cultures. We found that the combined treatment increased redox imbalance, enhanced the specific activities of antioxidant enzymes, and reduced the growth in cappz1 mutant (KO) strain. RNASeq data demonstrated that the presence of BM markedly elevated the number of differentially expressed genes in the MSB treated KO cultures. Accumulation of reactive oxygen species, increased iron content and fatty acid oxidation, as well as the inhibiting ergosterol biosynthesis and RNA metabolic processes explain, at least in part, the fungistatic effect caused by the combined stress exposure. We suggest that the synergism between MSB treatment and CaPpz1 inhibition could be considered in developing of a novel combinatorial antifungal strategy accompanying steroid therapy.

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