scholarly journals Bacillomycin D Produced by Bacillus amyloliquefaciens Is Involved in the Antagonistic Interaction with the Plant-Pathogenic Fungus Fusarium graminearum

2017 ◽  
Vol 83 (19) ◽  
Author(s):  
Qin Gu ◽  
Yang Yang ◽  
Qiming Yuan ◽  
Guangming Shi ◽  
Liming Wu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Fusarium Graminearum ◽  
Bacillus Amyloliquefaciens ◽  
Morphological Changes ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Strong Activity ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Bacillomycin D

ABSTRACT Fusarium graminearum (teleomorph: Ascomycota, Hypocreales, Gibberella, Gibberella zeae) is a destructive fungal pathogen that threatens the production and quality of wheat and barley worldwide. Controlling this toxin-producing pathogen is a significant challenge. In the present study, the commercially available strain Bacillus amyloliquefaciens (Bacteria, Firmicutes, Bacillales, Bacillus) FZB42 showed strong activity against F. graminearum. The lipopeptide bacillomycin D, produced by FZB42, was shown to contribute to the antifungal activity. Purified bacillomycin D showed strong activity against F. graminearum, and its 50% effective concentration was determined to be approximately 30 μg/ml. Analyses using scanning and transmission electron microscopy revealed that bacillomycin D caused morphological changes in the plasma membranes and cell walls of F. graminearum hyphae and conidia. Fluorescence microscopy combined with different dyes showed that bacillomycin D induced the accumulation of reactive oxygen species and caused cell death in F. graminearum hyphae and conidia. F. graminearum secondary metabolism also responded to bacillomycin D challenge, by increasing the production of deoxynivalenol. Biological control experiments demonstrated that bacillomycin D exerted good control of F. graminearum on corn silks, wheat seedlings, and wheat heads. In response to bacillomycin D, F. graminearum genes involved in scavenging reactive oxygen species were downregulated, whereas genes involved in the synthesis of deoxynivalenol were upregulated. Phosphorylation of MGV1 and HOG1, the mitogen-activated protein kinases of F. graminearum, was increased in response to bacillomycin D. Taken together, these findings reveal the mechanism of the antifungal action of bacillomycin D. IMPORTANCE Biological control of plant disease caused by Fusarium graminearum is desirable. Bacillus amyloliquefaciens FZB42 is a representative of the biocontrol bacterial strains. In this work, the lipopeptide bacillomycin D, produced by FZB42, showed strong fungicidal activity against F. graminearum. Bacillomycin D caused morphological changes in the plasma membrane and cell wall of F. graminearum, induced accumulation of reactive oxygen species, and ultimately caused cell death in F. graminearum. Interestingly, when F. graminearum was challenged with bacillomycin D, the deoxynivalenol production, gene expression, mitogen-activated protein kinase phosphorylation, and pathogenicity of F. graminearum were significantly altered. These findings clarified the mechanisms of the activity of bacillomycin D against F. graminearum and highlighted the potential of B. amyloliquefaciens FZB42 as a biocontrol agent against F. graminearum.

scholarly journals 5-Methoxyindole, a Chemical Homolog of Melatonin, Adversely Affects the Phytopathogenic Fungus Fusarium graminearum

2021 ◽  
Vol 22 (20) ◽  
pp. 10991
Author(s):  
Mengmeng Kong ◽  
Jing Liang ◽  
Qurban Ali ◽  
Wen Wen ◽  
Huijun Wu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Fusarium Graminearum ◽  
Reactive Oxygen ◽  
Cost Effective ◽  
Phytopathogenic Fungus ◽  
Oxygen Species ◽  
Strong Activity ◽  
Antifungal Action ◽  
Growth Formation ◽  
The Cost

Fusarium graminearum is a destructive fungal pathogen that threatens the production and quality of wheat, and controlling this pathogen is a significant challenge. As the cost-effective homolog of melatonin, 5-methoxyindole showed strong activity against F. graminearum. In the present study, our results showed the strong adverse activity of 5-methoxyindole against F. graminearum by inhibiting its growth, formation, and conidia germination. In addition, 5-methoxyindole could induce malformation, reactive oxygen species (ROS) accumulation, and cell death in F. graminearum hyphae and conidia. In response to 5-methoxyindole, F. graminearum genes involved in scavenging reactive oxygen species were significantly downregulated. Overall, these findings reveal the mechanism of antifungal action of melatonin-homolog 5-methoxyindole. To the best of our knowledge, this is the first report that a novel melatonin homolog confers strong antifungal activity against F. graminearum, and 5-methoxyindole is a potential compound for protecting wheat plants from F. graminearum infection.

scholarly journals Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Matthew De Furio ◽  
Sang Joon Ahn ◽  
Robert A. Burne ◽  
Stephen J. Hagen
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Dental Caries ◽  
Signaling Pathway ◽  
Streptococcus Mutans ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Content Type

ABSTRACTThe dental caries pathogenStreptococcus mutansis continually exposed to several types of stress in the oral biofilm environment. Oxidative stress generated by reactive oxygen species has a major impact on the establishment, persistence, and virulence ofS. mutans. Here, we combined fluorescent reporter-promoter fusions with single-cell imaging to study the effects of reactive oxygen species on activation of genetic competence inS. mutans. Exposure to paraquat, which generates superoxide anion, produced a qualitatively different effect on activation of expression of the gene for the master competence regulator, ComX, than did treatment with hydrogen peroxide (H2O2), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction ofcomXin a progressive and cumulative fashion, whereas the response to H2O2displayed a strong threshold behavior. Low concentrations of H2O2had little effect on induction ofcomXor the bacteriocin genecipB, but expression of these genes declined sharply if extracellular H2O2exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H2O2, depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H2O2affect theS. mutanscompetence signaling pathway differently, and that some portions of the competence signaling pathway are more sensitive to oxidative stress than others.IMPORTANCEStreptococcus mutansinhabits the oral biofilm, where it plays an important role in the development of dental caries. Environmental stresses such as oxidative stress influence the growth ofS. mutansand its important virulence-associated behaviors, such as genetic competence.S. mutanscompetence development is a complex behavior that involves two different signaling peptides and can exhibit cell-to-cell heterogeneity. Although oxidative stress is known to influenceS. mutanscompetence, it is not understood how oxidative stress interacts with the peptide signaling or affects heterogeneity. In this study, we used fluorescent reporters to probe the effect of reactive oxygen species on competence signaling at the single-cell level. Our data show that different reactive oxygen species have different effects onS. mutanscompetence, and that some portions of the signaling pathway are more acutely sensitive to oxidative stress than others.

scholarly journals Influence of PM2.5 on spermatogenesis dysfunction via the reactive-oxygen-species-mediated Mitogen-activated-protein-kinase signaling pathway

2019 ◽  
Vol 6 (4) ◽  
pp. 77-79
Author(s):  
Ruangrong Cheepsattayakorn
Keyword(s):  
Reactive Oxygen Species ◽  
Signaling Pathway ◽  
Reactive Oxygen ◽  
Human Sperm ◽  
Mapk Signaling ◽  
Autoimmune Response ◽  
Sperm Chromatin ◽  
Seminiferous Tubules ◽  
Oxygen Species ◽  
Mitogen Activated Protein

Approximately 15 % of the world‘s couples confront childless, and about 50 % of them are due to male reproductive disorders. Several previous studies demonstrated that PM2.5 particles has been consistently associated with critical human sperm reduction and impairment of human sperm chromatin and DNA from traffic exhaust pollution. Blood-testis barrier (BTB), a critically physical barrier between the seminiferous tubules and the blood vessels prevents sperm antigens from entering the blood circulation and facilitating and initiating an autoimmune response that contributing to spermatogenesis interference. Reactive oxygen species (ROS) are involved in the redox-sensitive signal transduction factors activation, such as Jun NH2-terminal kinase (JNK), p 38, extracellular signal-regulated kinase (ERK), and mitogen-activated protein kinases (MAPK) that critically influence BTB disruption. After PM2.5 exposure, there are decreased superoxide dismutase (SOD) expression, increased malondialdehyde (MDA) expression, increased nuclear factor erythroid 2-related factor 2 (Nrf-2) expression, increased expression of the four junctional proteins (β-catenin, Cx43, occludin, zonula occludens-1 (ZO-1)), thus improve sperm quality and quantity. PM2.5 particles markedly induce increasing phosphorylation of MAPKs via the ROS-mediated MAPK signaling pathway that causes BTB disruption, but this effect is lesser in the vitamins C and E intervention as well as increasing cleaved caspase-3 expression and the Bcl-2/Bax ratio. In conclusion, combined therapeutic administration of vitamins C and E can maintain the BTB integrity, reduce oxidative stress and cell apoptosis, and prevent toxic effects.

scholarly journals The Dynll1-Cox4i1 Complex Regulates Intracellular Pathogen Clearance via Release of Mitochondrial Reactive Oxygen Species

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Jiangbei Yuan ◽  
Zihan Zheng ◽  
Liting Wang ◽  
Haiying Ran ◽  
Xiangyu Tang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Listeria Monocytogenes ◽  
Membrane Proteins ◽  
Defense Mechanisms ◽  
Reactive Oxygen ◽  
Cellular Membrane ◽  
Oxygen Species ◽  
Dynein Light Chain ◽  
Mitochondrial Reactive Oxygen Species ◽  
Content Type

ABSTRACT Cellular membrane proteins are a critical part of the host defense mechanisms against infection and intracellular survival of Listeria monocytogenes. The complex spatiotemporal regulation of bacterial infection by various membrane proteins has been challenging to study. Here, using mass spectrometry analyses, we depicted the dynamic expression landscape of membrane proteins upon L. monocytogenes infection in dendritic cells. We showed that Dynein light chain 1 (Dynll1) formed a persistent complex with the mitochondrial cytochrome oxidase Cox4i1, which is disturbed by pathogen insult. We discovered that the dissociation of the Dynll1-Cox4i1 complex is required for the release of mitochondrial reactive oxygen species and serves as a regulator of intracellular proliferation of Listeria monocytogenes. Our study shows that Dynll1 is an inhibitor of mitochondrial reactive oxygen species and can serve as a potential molecular drug target for antibacterial treatment.

scholarly journals Role of Reactive Oxygen Species in Cancer Progression: Molecular Mechanisms and Recent Advancements

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 735 ◽  
Author(s):  
Vaishali Aggarwal ◽  
Hardeep Tuli ◽  
Ayşegül Varol ◽  
Falak Thakral ◽  
Mukerrem Yerer ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Protein Kinase ◽  
Cancer Cell ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Reactive Oxygen ◽  
Mitogen Activated Protein Kinase ◽  
Oxygen Species ◽  
Mitogen Activated Protein ◽  
High Concentrations

Reactive oxygen species (ROS) play a pivotal role in biological processes and continuous ROS production in normal cells is controlled by the appropriate regulation between the silver lining of low and high ROS concentration mediated effects. Interestingly, ROS also dynamically influences the tumor microenvironment and is known to initiate cancer angiogenesis, metastasis, and survival at different concentrations. At moderate concentration, ROS activates the cancer cell survival signaling cascade involving mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1/2 (MAPK/ERK1/2), p38, c-Jun N-terminal kinase (JNK), and phosphoinositide-3-kinase/ protein kinase B (PI3K/Akt), which in turn activate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF). At high concentrations, ROS can cause cancer cell apoptosis. Hence, it critically depends upon the ROS levels, to either augment tumorigenesis or lead to apoptosis. The major issue is targeting the dual actions of ROS effectively with respect to the concentration bias, which needs to be monitored carefully to impede tumor angiogenesis and metastasis for ROS to serve as potential therapeutic targets exogenously/endogenously. Overall, additional research is required to comprehend the potential of ROS as an effective anti-tumor modality and therapeutic target for treating malignancies.

scholarly journals Ascorbate-Dependent Peroxidase (APX) from Leishmania amazonensis Is a Reactive Oxygen Species-Induced Essential Enzyme That Regulates Virulence

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Lucia Xiang ◽  
Maria Fernanda Laranjeira-Silva ◽  
Fernando Y. Maeda ◽  
Jason Hauzel ◽  
Norma W. Andrews ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Molecular Mechanisms ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Macrophage Infection ◽  
Cutaneous Lesions ◽  
Signaling Mechanism ◽  
Content Type ◽  
Temporal Regulation ◽  
Metacyclic Promastigotes

ABSTRACT The molecular mechanisms underlying biological differences between two Leishmania species that cause cutaneous disease, L. major and L. amazonensis, are poorly understood. In L. amazonensis, reactive oxygen species (ROS) signaling drives differentiation of nonvirulent promastigotes into forms capable of infecting host macrophages. Tight spatial and temporal regulation of H2O2 is key to this signaling mechanism, suggesting a role for ascorbate-dependent peroxidase (APX), which degrades mitochondrial H2O2. Earlier studies showed that APX-null L. major parasites are viable, accumulate higher levels of H2O2, generate a greater yield of infective metacyclic promastigotes, and have increased virulence. In contrast, we found that in L. amazonensis, the ROS-inducible APX is essential for survival of all life cycle stages. APX-null promastigotes could not be generated, and parasites carrying a single APX allele were impaired in their ability to infect macrophages and induce cutaneous lesions in mice. Similar to what was reported for L. major, APX depletion in L. amazonensis enhanced differentiation of metacyclic promastigotes and amastigotes, but the parasites failed to replicate after infecting macrophages. APX expression restored APX single-knockout infectivity, while expression of catalytically inactive APX drastically reduced virulence. APX overexpression in wild-type promastigotes reduced metacyclogenesis, but enhanced intracellular survival following macrophage infection or inoculation into mice. Collectively, our data support a role for APX-regulated mitochondrial H2O2 in promoting differentiation of virulent forms in both L. major and L. amazonensis. Our results also uncover a unique requirement for APX-mediated control of ROS levels for survival and successful intracellular replication of L. amazonensis.

scholarly journals Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress

2019 ◽  
Vol 201 (22) ◽  
Author(s):  
Laura Barrientos-Moreno ◽  
María Antonia Molina-Henares ◽  
Marta Pastor-García ◽  
María Isabel Ramos-González ◽  
Manuel Espinosa-Urgel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Pseudomonas Putida ◽  
Reactive Oxygen ◽  
Full Detail ◽  
Oxygen Species ◽  
Arginine Biosynthesis ◽  
Content Type ◽  
And Oxidative Stress

ABSTRACT Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores—molecules with high affinity for iron—which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species. IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida. Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.

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