scholarly journals ThHog1 controls the hyperosmotic stress response in Trichoderma harzianum

Microbiology ◽  
2006 ◽  
Vol 152 (6) ◽  
pp. 1687-1700 ◽  
Author(s):  
Jesús Delgado-Jarana ◽  
Sonia Sousa ◽  
Fran González ◽  
Manuel Rey ◽  
Antonio Llobell
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Trichoderma Harzianum ◽  
Hyperosmotic Stress ◽  
Stress Conditions ◽  
Cross Resistance ◽  
Main Role ◽  
Wide Range ◽  
Mutant Strains

Trichoderma harzianum is a widespread mycoparasitic fungus, able to successfully colonize a wide range of substrates under different environmental conditions. Transcript profiling revealed a subset of genes induced in T. harzianum under hyperosmotic shock. The hog1 gene, a homologue of the MAPK HOG1 gene that controls the hyperosmotic stress response in Saccharomyces cerevisiae, was characterized. T. harzianum hog1 complemented the hog1Δ mutation in S. cerevisiae, but showed different features to yeast alleles: improved osmoresistance by expression of the hog1 allele and a lack of lethality when the hog1 F315S allele was overexpressed. ThHog1 protein was phosphorylated in T. harzianum under different stress conditions such as hyperosmotic or oxidative stress, among others. By using a ThHog1-GFP fusion, the protein was shown to be localized in nuclei under these stress conditions. Two mutant strains of T. harzianum were constructed: one carrying the hog1 F315S allele, and a knockdown hog1-silenced strain. The silenced strain was highly sensitive to osmotic stress, and showed intermediate levels of resistance against oxidative stress, indicating that the main role of ThHog1 protein is in the hyperosmotic stress response. Stress cross-resistance experiments showed evidences of a secondary role of ThHog1 in oxidative stress. The strain carrying the hog1 F315S allele was highly resistant to the calcineurin inhibitor cyclosporin A, which suggests the existence of links between the two pathways. The two mutant strains showed a strongly reduced antagonistic activity against the plant pathogens Phoma betae and Colletotrichum acutatum, which points to a role of ThHog1 protein in fungus–fungus interactions.

scholarly journals RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 823
Author(s):  
Cristiana Mateus ◽  
Ana Rita Nunes ◽  
Mónica Oleastro ◽  
Fernanda Domingues ◽  
Susana Ferreira
Keyword(s):  
Oxidative Stress ◽  
Human Serum ◽  
Ethidium Bromide ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Efflux Pumps ◽  
Bacterial Virulence ◽  
Relative Fitness ◽  
Mutant Strains

Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.

scholarly journals Mitochondria, Oxidative Stress, cAMP Signalling and Apoptosis: A Crossroads in Lymphocytes of Multiple Sclerosis, a Possible Role of Nutraceutics

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 21
Author(s):  
Anna Signorile ◽  
Anna Ferretta ◽  
Maddalena Ruggieri ◽  
Damiano Paolicelli ◽  
Paolo Lattanzio ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Multiple Sclerosis ◽  
T Lymphocytes ◽  
Main Role ◽  
Apoptosis Resistance ◽  
Nutraceutical Compounds ◽  
Camp Pathway ◽  
Central Nervous Systems ◽  
Genetic And Environmental Factors

Multiple sclerosis (MS) is a complex inflammatory and neurodegenerative chronic disease that involves the immune and central nervous systems (CNS). The pathogenesis involves the loss of blood–brain barrier integrity, resulting in the invasion of lymphocytes into the CNS with consequent tissue damage. The MS etiology is probably a combination of immunological, genetic, and environmental factors. It has been proposed that T lymphocytes have a main role in the onset and propagation of MS, leading to the inflammation of white matter and myelin sheath destruction. Cyclic AMP (cAMP), mitochondrial dysfunction, and oxidative stress exert a role in the alteration of T lymphocytes homeostasis and are involved in the apoptosis resistance of immune cells with the consequent development of autoimmune diseases. The defective apoptosis of autoreactive lymphocytes in patients with MS, allows these cells to perpetuate, within the CNS, a continuous cycle of inflammation. In this review, we discuss the involvement in MS of cAMP pathway, mitochondria, reactive oxygen species (ROS), apoptosis, and their interaction in the alteration of T lymphocytes homeostasis. In addition, we discuss a series of nutraceutical compounds that could influence these aspects.

scholarly journals Role of ALADIN in Human Adrenocortical Cells for Oxidative Stress Response and Steroidogenesis

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0124582 ◽  
Author(s):  
Ramona Jühlen ◽  
Jan Idkowiak ◽  
Angela E. Taylor ◽  
Barbara Kind ◽  
Wiebke Arlt ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Oxidative Stress Response ◽  
Adrenocortical Cells

PHYSICAL ACTIVITY AS HEALTHY INTERVENTION AGAINST SEVERE OXIDATIVE STRESS IN ELDERLY POPULATION

2013 ◽  
pp. 1-9
Author(s):  
C. TOMAS-ZAPICO ◽  
E. IGLESIAS-GUTIERREZ ◽  
B. FERNANDEZ-GARCIA ◽  
D. DE GONZALO-CALVO
Keyword(s):  
Oxidative Stress ◽  
Physical Activity ◽  
Elderly Population ◽  
Physiological Basis ◽  
Related Disease ◽  
Age Related ◽  
Wide Range ◽  
Health Related ◽  
Relevant Risk Factor

Severe oxidative stress is a relevant risk factor for major deleterious health-related events in olderpeople and is thought to be an important contributor to age-related disease. Literature has suggested oxidativestress as a therapeutic target for mitigating the biological decline and attenuating the occurrence of adverseclinical events in aged individuals. However, definitive treatments are not known. Regular and moderate physicalactivity has been proposed as possible intervention for slowing age-related decline. This healthy strategy presentsa wide range of beneficial aspects for elderly, from the reduction of morbidity, disability, frailty and mortalityrates to treatment of many age-related disorders. Importantly, the global benefits on health are not shared by anyother strategies. Nevertheless, the physiological basis by which exercise produces its benefits to the organism isnot fully understood. This review summarizes the evidence for the role of physical activity as potential healthyintervention for mitigating the negative aspects of aging through the modulation of the oxidative mechanisms.

An AraC/XylS Family Transcriptional Regulator Modulates the Oxidative Stress Response of Francisella tularensis

2021 ◽  
Author(s):  
Dina Marghani ◽  
Zhuo Ma ◽  
Anthony J. Centone ◽  
Weihua Huang ◽  
Meenakshi Malik ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Francisella Tularensis ◽  
Human Disease ◽  
Transcriptional Regulator ◽  
Intracellular Survival ◽  
Gram Negative ◽  
Expression Of Genes ◽  
Transcription Regulators

Francisella tularensis is a Gram-negative bacterium that causes a fatal human disease known as tularemia. The Centers for Disease Control have classified F. tularensis as Category A Tier-1 Select Agent. The virulence mechanisms of Francisella are not entirely understood. Francisella possesses very few transcription regulators, and most of these regulate the expression of genes involved in intracellular survival and virulence. The F. tularensis genome sequence analysis reveals an AraC ( FTL_ 0689) transcriptional regulator homologous to the AraC/XylS family of transcriptional regulators. In Gram-negative bacteria, AraC activates genes required for L-arabinose utilization and catabolism. The role of the FTL_ 0689 regulator in F. tularensis is not known. In this study, we characterized the role of FTL_ 0689 in gene regulation of F. tularensis and investigated its contribution to intracellular survival and virulence. The results demonstrate that FTL_0689 in Francisella is not required for L-arabinose utilization. Instead, FTL_ 0689 specifically regulates the expression of the oxidative and global stress response, virulence, metabolism, and other key pathways genes required by Francisella when exposed to oxidative stress. The FTL_0689 mutant is attenuated for intramacrophage growth and virulence in mice. Based on the deletion mutant phenotype, FTL_0689 was termed osrR ( o xidative s tress r esponse r egulator). Altogether, this study elucidates the role of the osrR transcriptional regulator in tularemia pathogenesis. IMPORTANCE: The virulence mechanisms of category A select agent Francisella tularensis , the causative agent of a fatal human disease known as tularemia, remain largely undefined. The present study investigated the role of a transcriptional regulator and its overall contribution to the oxidative stress resistance of F. tularensis . The results provide an insight into a novel gene regulatory mechanism, especially when Francisella is exposed to oxidative stress conditions. Understanding such Francisella - specific regulatory mechanisms will identify potential targets for developing effective therapies and vaccines to prevent tularemia.

scholarly journals Curcumin and Endometriosis

2020 ◽  
Vol 21 (7) ◽  
pp. 2440 ◽  
Author(s):  
Alexandre Vallée ◽  
Yves Lecarpentier
Keyword(s):  
Oxidative Stress ◽  
Inflammatory Responses ◽  
Uterine Cavity ◽  
Main Role ◽  
Oxygen Species ◽  
Inflammatory Agent ◽  
Gynecological Disorders ◽  
Anti Oxidant ◽  
Anti Inflammatory

Endometriosis is one of the main common gynecological disorders, which is characterized by the presence of glands and stroma outside the uterine cavity. Some findings have highlighted the main role of inflammation in endometriosis by acting on proliferation, apoptosis and angiogenesis. Oxidative stress, an imbalance between reactive oxygen species and antioxidants, could have a key role in the initiation and progression of endometriosis by resulting in inflammatory responses in the peritoneal cavity. Nevertheless, the mechanisms underlying this disease are still unclear and therapies are not currently efficient. Curcumin is a major anti-inflammatory agent. Several findings have highlighted the anti-oxidant, anti-inflammatory and anti-angiogenic properties of curcumin. The purpose of this review is to summarize the potential action of curcumin in endometriosis by acting on inflammation, oxidative stress, invasion and adhesion, apoptosis and angiogenesis.

scholarly journals Reassessing the Role of the Type II MqsRA Toxin-Antitoxin System in Stress Response and Biofilm Formation: mqsA Is Transcriptionally Uncoupled from mqsR

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Nathan Fraikin ◽  
Clothilde J. Rousseau ◽  
Nathalie Goeders ◽  
Laurence Van Melderen
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Biofilm Formation ◽  
Bile Salts ◽  
Regulatory Networks ◽  
Constitutive Expression ◽  
Toxin Gene ◽  
Global Regulator ◽  
Bacterial Physiology

ABSTRACT Toxin-antitoxin (TA) systems are broadly distributed modules whose biological roles remain mostly unknown. The mqsRA system is a noncanonical TA system in which the toxin and antitoxins genes are organized in operon but with the particularity that the toxin gene precedes that of the antitoxin. This system was shown to regulate global processes such as resistance to bile salts, motility, and biofilm formation. In addition, the MqsA antitoxin was shown to be a master regulator that represses the transcription of the csgD, cspD, and rpoS global regulator genes, thereby displaying a pleiotropic regulatory role. Here, we identified two promoters located in the toxin sequence driving the constitutive expression of mqsA, allowing thereby excess production of the MqsA antitoxin compared to the MqsR toxin. Our results show that both antitoxin-specific and operon promoters are not regulated by stresses such as amino acid starvation, oxidative shock, or bile salts. Moreover, we show that the MqsA antitoxin is not a global regulator as suggested, since the expression of csgD, cspD and rpoS is similar in wild-type and ΔmqsRA mutant strains. Moreover, these two strains behave similarly in terms of biofilm formation and sensitivity to oxidative stress or bile salts. IMPORTANCE There is growing controversy regarding the role of chromosomal toxin-antitoxin systems in bacterial physiology. mqsRA is a peculiar toxin-antitoxin system, as the gene encoding the toxin precedes that of the antitoxin. This system was previously shown to play a role in stress response and biofilm formation. In this work, we identified two promoters specifically driving the constitutive expression of the antitoxin, thereby decoupling the expression of antitoxin from the toxin. We also showed that mqsRA contributes neither to the regulation of biofilm formation nor to the sensitivity to oxidative stress and bile salts. Finally, we were unable to confirm that the MqsA antitoxin is a global regulator. Altogether, our data are ruling out the involvement of the mqsRA system in Escherichia coli regulatory networks.

The role of CSA and CSB protein in the oxidative stress response

2013 ◽  
Vol 134 (5-6) ◽  
pp. 261-269 ◽  
Author(s):  
Mariarosaria D’Errico ◽  
Barbara Pascucci ◽  
Egidio Iorio ◽  
Bennett Van Houten ◽  
Eugenia Dogliotti
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Oxidative Stress Response

scholarly journals TrmB, a tRNA m7G46 methyltransferase, plays a role in hydrogen peroxide resistance and positively modulates the translation of katA and katB mRNAs in Pseudomonas aeruginosa

2019 ◽  
Vol 47 (17) ◽  
pp. 9271-9281 ◽  
Author(s):  
Narumon Thongdee ◽  
Juthamas Jaroensuk ◽  
Sopapan Atichartpongkul ◽  
Jurairat Chittrakanwong ◽  
Kamonchanok Chooyoung ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Stress Response ◽  
Translational Regulation ◽  
Cellular Response ◽  
Oxidative Stress Response ◽  
Translation Efficiency ◽  
Trna Modification ◽  
Negative Effect

Abstract Cellular response to oxidative stress is a crucial mechanism that promotes the survival of Pseudomonas aeruginosa during infection. However, the translational regulation of oxidative stress response remains largely unknown. Here, we reveal a tRNA modification-mediated translational response to H2O2 in P. aeruginosa. We demonstrated that the P. aeruginosa trmB gene encodes a tRNA guanine (46)-N7-methyltransferase that catalyzes the formation of m7G46 in the tRNA variable loop. Twenty-three tRNA substrates of TrmB with a guanosine residue at position 46 were identified, including 11 novel tRNA substrates. We showed that loss of trmB had a strong negative effect on the translation of Phe- and Asp-enriched mRNAs. The trmB-mediated m7G modification modulated the expression of the catalase genes katA and katB, which are enriched with Phe/Asp codons at the translational level. In response to H2O2 exposure, the level of m7G modification increased, consistent with the increased translation efficiency of Phe- and Asp-enriched mRNAs. Inactivation of trmB led to decreased KatA and KatB protein abundance and decreased catalase activity, resulting in H2O2-sensitive phenotype. Taken together, our observations reveal a novel role of m7G46 tRNA modification in oxidative stress response through translational regulation of Phe- and Asp-enriched genes, such as katA and katB.

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