Engineering Stress Tolerance in Maize

A wide range of environmental stresses (such as chilling, ozone, high light, drought, and heat) can damage crop plants, with consequent high annual yield losses. A common factor in all these unrelated adverse conditions, called oxidative stress, is the enhanced production of active oxygen species (AOS) within several subcellular compartments of the plant. AOS can react very rapidly with DNA, lipids and proteins, causing severe cellular damage. Under normal growth conditions, AOS are efficiently scavenged by both enzymatic and non-enzymatic detoxification mechanisms. Nevertheless, during prolonged stress conditions such detoxification systems get saturated and damage occurs. The main players within the defence system are superoxide dismutases, ascorbate peroxidase, and catalases. These enzymes directly eliminate the harmful AOS. By enhancing the levels of these proteins in transgenic plants via transformation technology the improvement of tolerance against oxidative stress is being attempted. In our research, we are generating transgenic maize lines that overproduce various antioxidative stress enzymes and we are assessing the performance of these plants during chilling stress.

Download Full-text

Oxidative stress-induced parkin misfolding, aggregation, and toxicity

10.21203/rs.3.rs-33898/v1 ◽

2020 ◽

Author(s):

Martin Duennwald ◽

Gary S. Shaw ◽

Mohammad A. Esmaeili ◽

Jane R. Rylett ◽

Susanne Schmid ◽

...

Keyword(s):

Oxidative Stress ◽

Disulfide Bonds ◽

Protein Misfolding ◽

Protein Quality ◽

Normal Growth ◽

Growth Conditions ◽

Cellular Protein ◽

Loss Of Function ◽

Underlying Mechanisms

Abstract Background: Excess oxidative stress and protein misfolding are major hallmarks of neurodegenerative disease, including Parkinson’s disease (PD). Mutations in the genes encoding the ubiquitin ligase parkin cause autosomal recessive juvenile forms of Parkinsonism by the loss of parkin function in mitochondrial homeostasis and cellular protein quality control, generally. Dysfunction of parkin might also contribute to sporadic forms of PD, yet the underlying mechanisms remain mostly unexplored. Methods: We obtained key results from studies in human PD brains, a mouse model, yeast, cultured neuronal cells, and in vitro biochemistry. Human postmortem Medial Temporal Gyrus tissue was fixed for immunohistochemistry. We performed biochemical analyses of protein lysates from human brain, mouse brain, yeast and cells to assess parkin modification by oxidative stress under normal growth conditions and more so under oxidative stress. Results: Our results reveal that oxidative stress damages parkin by inducing the formation of aberrant intra- and inter-molecular disulfide bonds, leading to parkin misfolding and inclusion formation, which is toxic to cells. We furthermore find that parkin is most severely oxidized in its active conformation. Conclusion: Collectively, our study identifies a mechanism by which protein oxidation can contribute to neurodegeneration in PD by combining loss of function with toxic gain of function mechanisms.

Download Full-text

The Effect ofBabesia divergensInfection on the Spleen of Mongolian Gerbils

BioMed Research International ◽

10.1155/2014/483854 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

Mohamed A. Dkhil ◽

Saleh Al-Quraishy ◽

Mohamed S. Al-Khalifa

Keyword(s):

Oxidative Stress ◽

Cell Cycle ◽

Protein Carbonyl ◽

Splenic Tissue ◽

Cellular Damage ◽

Mongolian Gerbils ◽

Protein Carbonyl Content ◽

Wide Range ◽

Cell Cycle Alteration ◽

Nitrite Nitrate

Babesiosis is caused by intraerythrocytic protozoan parasites transmitted by ticks and affects a wide range of domestic and wild animals and occasionally humans. The current study aimed to investigate the effect ofB. divergensinfected erythrocytes on spleen histopathology, cell cycle alteration, and the presence of oxidative stress. Mongolian gerbils were challenged with 5 × 106 Babesia divergensinfected erythrocytes. Parasitemia reached approximately 77% at day 5 postinfection. Infection also induced injury of the spleen. This was evidenced with (i) increases in cellular damage of the spleen, (ii) decrease in antioxidant capacity as indicated by decreased glutathione, catalase, and superoxide dismutase levels, (iii) increased production of malondialdehyde and nitric oxide derived products (nitrite/nitrate), and (iv) increased lactic acid dehydrogenase activity and protein carbonyl content in the spleen. Infection interfered with normal cell cycle of the spleen cells at G0/G1, S, and G2/M phases. On the basis of the above results it can be hypothesized thatB. divergensinfected erythrocytes could alter the spleen histopathology and cause cell cycle alteration and induce oxidative stress in splenic tissue.

Download Full-text

Phytohormones Regulate Accumulation of Osmolytes Under Abiotic Stress

Biomolecules ◽

10.3390/biom9070285 ◽

2019 ◽

Vol 9 (7) ◽

pp. 285 ◽

Cited By ~ 68

Author(s):

Anket Sharma ◽

Babar Shahzad ◽

Vinod Kumar ◽

Sukhmeen Kaur Kohli ◽

Gagan Preet Singh Sidhu ◽

...

Keyword(s):

Oxidative Stress ◽

Abiotic Stresses ◽

Compatible Solutes ◽

Plant Cells ◽

Normal Growth ◽

Cellular Damage ◽

Oxygen Species ◽

Osmolyte Accumulation ◽

Cellular Machinery ◽

Underlying Mechanisms

Plants face a variety of abiotic stresses, which generate reactive oxygen species (ROS), and ultimately obstruct normal growth and development of plants. To prevent cellular damage caused by oxidative stress, plants accumulate certain compatible solutes known as osmolytes to safeguard the cellular machinery. The most common osmolytes that play crucial role in osmoregulation are proline, glycine-betaine, polyamines, and sugars. These compounds stabilize the osmotic differences between surroundings of cell and the cytosol. Besides, they also protect the plant cells from oxidative stress by inhibiting the production of harmful ROS like hydroxyl ions, superoxide ions, hydrogen peroxide, and other free radicals. The accumulation of osmolytes is further modulated by phytohormones like abscisic acid, brassinosteroids, cytokinins, ethylene, jasmonates, and salicylic acid. It is thus important to understand the mechanisms regulating the phytohormone-mediated accumulation of osmolytes in plants during abiotic stresses. In this review, we have discussed the underlying mechanisms of phytohormone-regulated osmolyte accumulation along with their various functions in plants under stress conditions.

Download Full-text

Plant dehydrins — Tissue location, structure and function

Cellular & Molecular Biology Letters ◽

10.2478/s11658-006-0044-0 ◽

2006 ◽

Vol 11 (4) ◽

Cited By ~ 232

Author(s):

Tadeusz Rorat

Keyword(s):

Lipid Membranes ◽

Higher Plants ◽

Normal Growth ◽

Lipid Vesicles ◽

Structural Type ◽

Growth Conditions ◽

Main Question ◽

Cellular Dehydration ◽

Wide Range

AbstractDehydrins (DHNs) are part of a large group of highly hydrophilic proteins known as LEA (Late Embryogenesis Abundant). They were originally identified as group II of the LEA proteins. The distinctive feature of all DHNs is a conserved, lysine-rich 15-amino acid domain, EKKGIMDKIKEKLPG, named the K-segment. It is usually present near the C-terminus. Other typical dehydrin features are: a track of Ser residues (the S-segment); a consensus motif, T/VDEYGNP (the Y-segment), located near the N-terminus; and less conserved regions, usually rich in polar amino acids (the Φ-segments). They do not display a well-defined secondary structure. The number and order of the Y-, S-and K-segments define different DHN sub-classes: YnSKn, YnKn, SKn, Kn and KnS. Dehydrins are distributed in a wide range of organisms including the higher plants, algae, yeast and cyanobacteria. They accumulate late in embryogenesis, and in nearly all the vegetative tissues during normal growth conditions and in response to stress leading to cellular dehydration (e.g. drought, low temperature and salinity). DHNs are localized in different cell compartments, such as the cytosol, nucleus, mitochondria, vacuole, and the vicinity of the plasma membrane; however, they are primarily localized to the cytoplasm and nucleus. The precise function of dehydrins has not been established yet, but in vitro experiments revealed that some DHNs (YSKn-type) bind to lipid vesicles that contain acidic phospholipids, and others (KnS) were shown to bind metals and have the ability to scavenge hydroxyl radicals [Asghar, R. et al. Protoplasma 177 (1994) 87–94], protect lipid membranes against peroxidation or display cryoprotective activity towards freezing-sensitive enzymes. The SKn-and K-type seem to be directly involved in cold acclimation processes. The main question arising from the in vitro findings is whether each DHN structural type could possess a specific function and tissue distribution. Much recent in vitro data clearly indicates that dehydrins belonging to different subclasses exhibit distinct functions.

Download Full-text

COE2 Is Required for the Root Foraging Response to Nitrogen Limitation

International Journal of Molecular Sciences ◽

10.3390/ijms23020861 ◽

2022 ◽

Vol 23 (2) ◽

pp. 861

Author(s):

Rui Wu ◽

Zhixin Liu ◽

Jiajing Wang ◽

Chenxi Guo ◽

Yaping Zhou ◽

...

Keyword(s):

Nitric Oxide ◽

Root Development ◽

Nitrogen Limitation ◽

Lateral Roots ◽

Root Hairs ◽

Normal Growth ◽

Growth Conditions ◽

Lateral Root Development ◽

New Findings ◽

Wide Range

There are numerous exchanges of signals and materials between leaves and roots, including nitrogen, which is one of the essential nutrients for plant growth and development. In this study we identified and characterized the Chlorophyll A/B-Binding Protein (CAB) (named coe2 for CAB overexpression 2) mutant, which is defective in the development of chloroplasts and roots under normal growth conditions. The phenotype of coe2 is caused by a mutation in the Nitric Oxide Associated (NOA1) gene that is implicated in a wide range of chloroplast functions including the regulation of metabolism and signaling of nitric oxide (NO). A transcriptome analysis reveals that expression of genes involved in metabolism and lateral root development are strongly altered in coe2 seedlings compared with WT. COE2 is expressed in hypocotyls, roots, root hairs, and root caps. Both the accumulation of NO and the growth of lateral roots are enhanced in WT but not in coe2 under nitrogen limitation. These new findings suggest that COE2-dependent signaling not only coordinates gene expression but also promotes chloroplast development and function by modulating root development and absorption of nitrogen compounds.

Download Full-text

Temperature-Dependent Requirement for Catalase in Aerobic Growth of Listeria monocytogenes F2365

Applied and Environmental Microbiology ◽

10.1128/aem.01223-10 ◽

2010 ◽

Vol 76 (21) ◽

pp. 6998-7003 ◽

Cited By ~ 24

Author(s):

Reha Onur Azizoglu ◽

Sophia Kathariou

Keyword(s):

Oxidative Stress ◽

Listeria Monocytogenes ◽

Stress Responses ◽

Normal Growth ◽

Severe Illness ◽

Aerobic Growth ◽

Transposon Insertion ◽

Wide Range ◽

The Impact ◽

Oxidative Stress Responses

ABSTRACT Listeria monocytogenes is a Gram-positive, psychrotrophic, facultative intracellular food-borne pathogen responsible for severe illness (listeriosis). The bacteria can grow in a wide range of temperatures (1 to 45°C), and low-temperature growth contributes to the food safety hazards associated with contamination of ready-to-eat foods with this pathogen. To assess the impact of oxidative stress responses on the ability of L. monocytogenes to grow at low temperatures and to tolerate repeated freeze-thaw stress (cryotolerance), we generated and characterized a catalase-deficient mutant of L. monocytogenes F2365 harboring a mariner-based transposon insertion in the catalase gene (kat). When grown aerobically on blood-free solid medium, the kat mutant exhibited impaired growth, with the extent of impairment increasing with decreasing temperature, and no growth was detected at 4°C. Aerobic growth in liquid was impaired at 4°C, especially under aeration, but not at higher temperatures (10, 25, or 37°C). Genetic complementation of the mutant with the intact kat restored normal growth, confirming that inactivation of this gene was responsible for the growth impairment. In spite of the expected impact of oxidative stress responses on cryotolerance, cryotolerance of the kat mutant was not affected.

Download Full-text

Nucleoredoxin guards against oxidative stress by protecting antioxidant enzymes

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1703344114 ◽

2017 ◽

Vol 114 (31) ◽

pp. 8414-8419 ◽

Cited By ~ 35

Author(s):

Sophie Kneeshaw ◽

Rumana Keyani ◽

Valérie Delorme-Hinoux ◽

Lisa Imrie ◽

Gary J. Loake ◽

...

Keyword(s):

Oxidative Stress ◽

Stress Responses ◽

Cellular Damage ◽

Antioxidant Systems ◽

Oxygen Species ◽

Optimal Activity ◽

Substrate Interaction ◽

Wide Range ◽

Scavenging Enzymes ◽

Reduced State

Cellular accumulation of reactive oxygen species (ROS) is associated with a wide range of developmental and stress responses. Although cells have evolved to use ROS as signaling molecules, their chemically reactive nature also poses a threat. Antioxidant systems are required to detoxify ROS and prevent cellular damage, but little is known about how these systems manage to function in hostile, ROS-rich environments. Here we show that during oxidative stress in plant cells, the pathogen-inducible oxidoreductase Nucleoredoxin 1 (NRX1) targets enzymes of major hydrogen peroxide (H2O2)-scavenging pathways, including catalases. Mutant nrx1 plants displayed reduced catalase activity and were hypersensitive to oxidative stress. Remarkably, catalase was maintained in a reduced state by substrate-interaction with NRX1, a process necessary for its H2O2-scavenging activity. These data suggest that unexpectedly H2O2-scavenging enzymes experience oxidative distress in ROS-rich environments and require reductive protection from NRX1 for optimal activity.

Download Full-text

Antioxidant Functions of Nitric Oxide Synthase in a Methicillin SensitiveStaphylococcus aureus

International Journal of Microbiology ◽

10.1155/2013/312146 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 13

Author(s):

Manisha Vaish ◽

Vineet K. Singh

Keyword(s):

Oxidative Stress ◽

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Normal Growth ◽

Growth Conditions ◽

Nitric Oxide Donor ◽

Wild Type ◽

Gene Encoding ◽

Stress Studies ◽

Oxide Synthase

Nitric oxide and its derivative peroxynitrites are generated by host defense system to control bacterial infection. However certain Gram positive bacteria includingStaphylococcus aureuspossess a gene encoding nitric oxide synthase (SaNOS) in their chromosome. In this study it was determined that under normal growth conditions, expression ofSaNOSwas highest during early exponential phase of the bacterial growth. In oxidative stress studies, deletion ofSaNOSled to increased susceptibility of the mutant cells compared to wild-typeS. aureus. While inhibition ofSaNOSactivity by the addition of L-NAME increased sensitivity of the wild-typeS. aureusto oxidative stress, the addition of a nitric oxide donor, sodium nitroprusside, restored oxidative stress tolerance of theSaNOSmutant. TheSaNOSmutant also showed reduced survival after phagocytosis by PMN cells with respect to wild-typeS. aureus.

Download Full-text

Drug Delivery Strategies for Curcumin and Other Natural Nrf2 Modulators of Oxidative Stress-Related Diseases

Pharmaceutics ◽

10.3390/pharmaceutics13122137 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2137

Author(s):

Nina Katarina Grilc ◽

Matej Sova ◽

Julijana Kristl

Keyword(s):

Oxidative Stress ◽

Drug Delivery ◽

Oral Bioavailability ◽

Drug Delivery Systems ◽

Molecular Mechanisms ◽

Delivery Systems ◽

Cellular Damage ◽

Related Factor ◽

Wide Range

Oxidative stress is associated with a wide range of diseases characterised by oxidant-mediated disturbances of various signalling pathways and cellular damage. The only effective strategy for the prevention of cellular damage is to limit the production of oxidants and support their efficient removal. The implication of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the cellular redox status has spurred new interest in the use of its natural modulators (e.g., curcumin, resveratrol). Unfortunately, most natural Nrf2 modulators are poorly soluble and show extensive pre-systemic metabolism, low oral bioavailability, and rapid elimination, which necessitates formulation strategies to circumvent these limitations. This paper provides a brief introduction on the cellular and molecular mechanisms involved in Nrf2 modulation and an overview of commonly studied formulations for the improvement of oral bioavailability and in vivo pharmacokinetics of Nrf2 modulators. Some formulations that have also been studied in vivo are discussed, including solid dispersions, self-microemulsifying drug delivery systems, and nanotechnology approaches, such as polymeric and solid lipid nanoparticles, nanocrystals, and micelles. Lastly, brief considerations of nano drug delivery systems for the delivery of Nrf2 modulators to the brain, are provided. The literature reviewed shows that the formulations discussed can provide various improvements to the bioavailability and pharmacokinetics of natural Nrf2 modulators. This has been demonstrated in animal models and clinical studies, thereby increasing the potential for the translation of natural Nrf2 modulators into clinical practice.

Download Full-text

Overlapping Roles of the Cytoplasmic and Mitochondrial Redox Regulatory Systems in the Yeast Saccharomyces cerevisiae

Eukaryotic Cell ◽

10.1128/ec.4.2.392-400.2005 ◽

2005 ◽

Vol 4 (2) ◽

pp. 392-400 ◽

Cited By ~ 60

Author(s):

Eleanor W. Trotter ◽

Chris M. Grant

Keyword(s):

Oxidative Stress ◽

Saccharomyces Cerevisiae ◽

Redox State ◽

Redox Homeostasis ◽

Thioredoxin Reductase ◽

Normal Growth ◽

Growth Conditions ◽

Reduced Form ◽

Yeast Saccharomyces Cerevisiae ◽

Thioredoxin System

ABSTRACT Thioredoxins are small, highly conserved oxidoreductases which are required to maintain the redox homeostasis of the cell. Saccharomyces cerevisiae contains a cytoplasmic thioredoxin system (TRX1, TRX2, and TRR1) as well as a complete mitochondrial thioredoxin system, comprising a thioredoxin (TRX3) and a thioredoxin reductase (TRR2). In the present study we have analyzed the functional overlap between the two systems. By constructing mutant strains with deletions of both the mitochondrial and cytoplasmic systems (trr1 trr2 and trx1 trx2 trx3), we show that cells can survive in the absence of both systems. Analysis of the redox state of the cytoplasmic thioredoxins reveals that they are maintained independently of the mitochondrial system. Similarly, analysis of the redox state of Trx3 reveals that it is maintained in the reduced form in wild-type cells and in mutants lacking components of the cytoplasmic thioredoxin system (trx1 trx2 or trr1). Surprisingly, the redox state of Trx3 is also unaffected by the loss of the mitochondrial thioredoxin reductase (trr2) and is largely maintained in the reduced form unless cells are exposed to an oxidative stress. Since glutathione reductase (Glr1) has been shown to colocalize to the cytoplasm and mitochondria, we examined whether loss of GLR1 influences the redox state of Trx3. During normal growth conditions, deletion of TRR2 and GLR1 was found to result in partial oxidation of Trx3, indicating that both Trr2 and Glr1 are required to maintain the redox state of Trx3. The oxidation of Trx3 in this double mutant is even more pronounced during oxidative stress or respiratory growth conditions. Taken together, these data indicate that Glr1 and Trr2 have an overlapping function in the mitochondria.

Download Full-text