scholarly journals NAD(P)H Cytochrome b5 Oxidoreductase Deficiency in Leishmania major Results in Impaired Linoleate Synthesis Followed by Increased Oxidative Stress and Cell Death

2012 ◽  
Vol 287 (42) ◽  
pp. 34992-35003 ◽  
Author(s):  
Supratim Mukherjee ◽  
Sumit Sen Santara ◽  
Shantanabha Das ◽  
Moumita Bose ◽  
Jayasree Roy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Leishmania Major ◽  
Flow Cytometric Analysis ◽  
Physiological Role ◽  
Gene Replacement ◽  
Spectral Studies ◽  
Null Cell ◽  
Knock Out ◽  
Δ9 Desaturase

NAD(P)H cytochrome b5 oxidoreductase (Ncb5or), comprising cytochrome b5 and cytochrome b5 reductase domains, is widely distributed in eukaryotic organisms. Although Ncb5or plays a crucial role in lipid metabolism of mice, so far no Ncb5or gene has been reported in the unicellular parasitic protozoa Leishmania species. We have cloned, expressed, and characterized Ncb5or gene from Leishmania major. Steady state catalysis and spectral studies show that NADH can quickly reduce the ferric state of the enzyme to the ferrous state and is able to donate an electron(s) to external acceptors. To elucidate its exact physiological role in Leishmania, we attempted to create NAD(P)H cytochrome b5 oxidoreductase from L. major (LmNcb5or) knock-out mutants by targeted gene replacement technique. A free fatty acid profile in knock-out (KO) cells reveals marked deficiency in linoleate and linolenate when compared with wild type (WT) or overexpressing cells. KO culture has a higher percentage of dead cells compared with both WT and overexpressing cells. Increased O2 uptake, uncoupling and ATP synthesis, and loss of mitochondrial membrane potential are evident in KO cells. Flow cytometric analysis reveals the presence of a higher concentration of intracellular H2O2, indicative of increased oxidative stress in parasites lacking LmNcb5or. Cell death is significantly reduced when the KO cells are pretreated with BSA bound linoleate. Real time PCR studies demonstrate a higher Δ12 desaturase, superoxide dismutase, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA with a concomitant fall in Δ9 desaturase mRNA expression in LmNcb5or null cell line. Together these findings suggest that decreased linoleate synthesis, and increased oxidative stress and apoptosis are the major consequences of LmNcb5or deficiency in Leishmania.

scholarly journals An FYVE-Domain-Containing Protein, PsFP1, Is Involved in Vegetative Growth, Oxidative Stress Response and Virulence of Phytophthora sojae

2021 ◽  
Vol 22 (12) ◽  
pp. 6601
Author(s):  
Jinhui Zhang ◽  
Xiaoran Du ◽  
Xin Zhou ◽  
Duo Jin ◽  
Jianqiang Miao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Membrane Trafficking ◽  
Vegetative Growth ◽  
Genome Mining ◽  
Gene Replacement ◽  
Wide Distribution ◽  
Stress Sensitivity ◽  
Phytophthora Sojae ◽  
Knock Out ◽  
Fyve Domain

Proteins that contain the FYVE zinc-finger domain are recruited to PtdIns3P-containing membranes, participating in numerous biological processes such as membrane trafficking, cytoskeletal regulation, and receptor signaling. However, the genome-wide distribution, evolution, and biological functions of FYVE-containing proteins are rarely reported for oomycetes. By genome mining of Phytophthora sojae, two proteins (PsFP1 and PsFP2) with a combination of the FYVE domain and the PX domain (a major phosphoinositide binding module) were found. To clarify the functions of PsFP1 and PsFP2, the CRISPR/Cas9-mediated gene replacement system was used to knock out the two genes respectively. Only heterozygous deletion mutants of PsFP1 were recovered, and the expression level of PsFP1 in the heterozygous knockout transformants was significantly down-regulated. These PsFP1 mutants showed a decrease in mycelial growth and pathogenicity and were more sensitive to hydrogen peroxide. These phenotypes were recovered to the level of wild-type by overexpression PsFP1 gene in the PsFP1 heterozygous knockout transformant. In contrast, deletion of PsFP2 had no significant effect on vegetative growth, asexual and sexual reproduction, pathogenicity, or oxidative stress sensitivity. PsFP1 was primarily localized in vesicle-like structures and both the FYVE and PX domains are important for its localization. Overall, our results indicate that PsFP1 plays an important role in the vegetative growth and virulence of P. sojae.

scholarly journals The Role of Pseudo-Orthocaspase (SyOC) of Synechocystis sp. PCC 6803 in Attenuating the Effect of Oxidative Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Saul Lema A ◽  
Marina Klemenčič ◽  
Franziska Völlmy ◽  
Maarten Altelaar ◽  
Christiane Funk
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Building Blocks ◽  
Amino Acid Residues ◽  
Knock Out ◽  
Functional Homology ◽  
Its Gene ◽  
Pcc 6803

Caspases are proteases, best known for their involvement in the execution of apoptosis—a subtype of programmed cell death, which occurs only in animals. These proteases are composed of two structural building blocks: a proteolytically active p20 domain and a regulatory p10 domain. Although structural homologs appear in representatives of all other organisms, their functional homology, i.e., cell death depending on their proteolytical activity, is still much disputed. Additionally, pseudo-caspases and pseudo-metacaspases, in which the catalytic histidine-cysteine dyad is substituted with non-proteolytic amino acid residues, were shown to be involved in cell death programs. Here, we present the involvement of a pseudo-orthocaspase (SyOC), a prokaryotic caspase-homolog lacking the p10 domain, in oxidative stress in the model cyanobacterium Synechocystis sp. PCC 6803. To study the in vivo impact of this pseudo-protease during oxidative stress its gene expression during exposure to H2O2 was monitored by RT-qPCR. Furthermore, a knock-out mutant lacking the pseudo-orthocaspase gene was designed, and its survival and growth rates were compared to wild type cells as well as its proteome. Deletion of SyOC led to cells with a higher tolerance toward oxidative stress, suggesting that this protein may be involved in a pro-death pathway.

scholarly journals Pathogenicity of an Invasive Bacterium, Aeromonas salmonicida in Indian Major Carp, Labeo rohita – Evaluation of Immune Response Using Effective Molecular Markers

2020 ◽  
Vol 4 (1) ◽  
pp. 01-17
Author(s):  
Subharthi Pal ◽  
Dola Roy ◽  
Sriparna Datta Ray ◽  
Sumit Homechaudhuri
Keyword(s):  
Oxidative Stress ◽  
Immune Response ◽  
Cell Death ◽  
Labeo Rohita ◽  
Apoptotic Cell ◽  
Flow Cytometric Analysis ◽  
Aeromonas Salmonicida ◽  
Apoptotic Cell Death ◽  
Antimicrobial Protein ◽  
Histopathological Analysis

Effects of Aeromonas salmonicida on the non-specific immune response, oxidative stress and subsequent cell death in liver and spleen of Labeo rohita exposed to asymptomatic dose (2 × 107 CFU/mL) of pathogen were studied. Evaluation of in vivo non-specific immunity via Nitro blue tetrazolium (NBT) reduction assay, myeloperoxidase (MPO) assay and serum bactericidal activity assay exhibited significant alterations among infected fishes, indicating temporary surge of innate immune responses. Considerable cell death and damage was observed in the histopathological analysis of liver and spleen in the infected fishes. Flow cytometric analysis by FITC-Annexin V/PI conclusively indicated triggering of apoptotic cell death in both organs. Relative expression of pro-inflammatory cytokine (TNFα) gene, antimicrobial protein producing genes (Lysozyme C and Lysozyme G) and apoptosis effector molecule (Caspase 3) gene were increased significantly both in liver and spleen of A. salmonicida treated fishes. In conclusion, infection with A. salmonicida at asymptomatic level resulted in severe oxidative stress that, caused apoptotic cell death. Since facultative pathogen eradication is not possible in open water or flowthrough aquaculture systems, this remains a crucial area of scientific research and the results obtained in the present study might provide better understanding of prophylactic, diagnostic and therapeutic measures during aquaculture.

scholarly journals Old Yellow Enzymes, Highly Homologous FMN Oxidoreductases with Modulating Roles in Oxidative Stress and Programmed Cell Death in Yeast

2007 ◽  
Vol 282 (49) ◽  
pp. 36010-36023 ◽  
Author(s):  
Osama Odat ◽  
Samer Matta ◽  
Hadi Khalil ◽  
Sotirios C. Kampranis ◽  
Raymond Pfau ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Antioxidant Activities ◽  
Ros Generation ◽  
Oxidized Glutathione ◽  
Wild Type ◽  
Antioxidant Genes ◽  
Knock Out ◽  
Chronological Aging

In a genetic screen to identify modifiers of Bax-dependent lethality in yeast, the C terminus of OYE2 was isolated based on its capacity to restore sensitivity to a Bax-resistant yeast mutant strain. Overexpression of full-length OYE2 suppresses Bax lethality in yeast, lowers endogenous reactive oxygen species (ROS), increases resistance to H2O2-induced programmed cell death (PCD), and significantly lowers ROS levels generated by organic prooxidants. Reciprocally, Δoye2 yeast strains are sensitive to prooxidant-induced PCD. Overexpression and knock-out analysis indicate these OYE2 antioxidant activities are opposed by OYE3, a highly homologous heterodimerizing protein, which functions as a prooxidant promoting H2O2-induced PCD in wild type yeast. To exert its effect OYE3 requires the presence of OYE2. Deletion of the 12 C-terminal amino acids and catalytic inactivation of OYE2 by a Y197F mutation enhance significantly survival upon H2O2-induced PCD in wild type cells, but accelerate PCD in Δoye3 cells, implicating the oye2p-oye3p heterodimer for promoting cell death upon oxidative stress. Unexpectedly, a strain with a double knock-out of these genes (Δoye2 oye3) is highly resistant to H2O2-induced PCD, exhibits increased respiratory capacity, and undergoes less cell death during the adaptive response in chronological aging. Simultaneous deletion of OYE2 and other antioxidant genes hyperinduces endogenous levels of ROS, promoting H2O2-induced cell death: in Δoye2 glr1 yeast high levels of oxidized glutathione elicited gross morphological aberrations involving the actin cytoskeleton and defects in organelle partitioning. Altering the ratio of reduced to oxidized glutathione by exogenous addition of GSH fully reversed these alterations. Based on this work, OYE proteins are firmly placed in the signaling network connecting ROS generation, PCD modulation, and cytoskeletal dynamics in yeast.

Glial cytotoxicity of low doses of cadmium as a model of heavy metal pollution influence on vertebrates

2020 ◽  
Vol 31 (1) ◽  
pp. 3-10
Author(s):  
V. S. Nedzvetsky ◽  
V. Ya. Gasso ◽  
A. M. Hahut ◽  
I. A. Hasso
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Oxidative Damage ◽  
Cadmium Chloride ◽  
Glioma Cells ◽  
Low Doses ◽  
Genotoxic Effects ◽  
Cadmium Ions

Cadmium is a common transition metal that entails an extremely wide range of toxic effects in humans and animals. The cytotoxicity of cadmium ions and its compounds is due to various genotoxic effects, including both DNA damage and chromosomal aberrations. Some bone diseases, kidney and digestive system diseases are determined as pathologies that are closely associated with cadmium intoxication. In addition, cadmium is included in the list of carcinogens because of its ability to initiate the development of tumors of several forms of cancer under conditions of chronic or acute intoxication. Despite many studies of the effects of cadmium in animal models and cohorts of patients, in which cadmium effects has occurred, its molecular mechanisms of action are not fully understood. The genotoxic effects of cadmium and the induction of programmed cell death have attracted the attention of researchers in the last decade. In recent years, the results obtained for in vivo and in vitro experimental models have shown extremely high cytotoxicity of sublethal concentrations of cadmium and its compounds in various tissues. One of the most studied causes of cadmium cytotoxicity is the development of oxidative stress and associated oxidative damage to macromolecules of lipids, proteins and nucleic acids. Brain cells are most sensitive to oxidative damage and can be a critical target of cadmium cytotoxicity. Thus, oxidative damage caused by cadmium can initiate genotoxicity, programmed cell death and inhibit their viability in the human and animal brains. To test our hypothesis, cadmium cytotoxicity was assessed in vivo in U251 glioma cells through viability determinants and markers of oxidative stress and apoptosis. The result of the cell viability analysis showed the dose-dependent action of cadmium chloride in glioma cells, as well as the generation of oxidative stress (p <0.05). Calculated for 48 hours of exposure, the LD50 was 3.1 μg×ml-1. The rates of apoptotic death of glioma cells also progressively increased depending on the dose of cadmium ions. A high correlation between cadmium concentration and apoptotic response (p <0.01) was found for cells exposed to 3–4 μg×ml-1 cadmium chloride. Moreover, a significant correlation was found between oxidative stress (lipid peroxidation) and induction of apoptosis. The results indicate a strong relationship between the generation of oxidative damage by macromolecules and the initiation of programmed cell death in glial cells under conditions of low doses of cadmium chloride. The presented results show that cadmium ions can induce oxidative damage in brain cells and inhibit their viability through the induction of programmed death. Such effects of cadmium intoxication can be considered as a model of the impact of heavy metal pollution on vertebrates.

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