scholarly journals Vascular and non-vascular transmission of systemic reactive oxygen signals during wounding and heat stress

2021 ◽  
Author(s):  
Sara I Zandalinas ◽  
Ron Mittler
Keyword(s):  
Heat Stress ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Vascular Bundles ◽  
Transcript Accumulation ◽  
Mesophyll Cells ◽  
Single Leaf ◽  
Cell Layers ◽  
Systemic Responses ◽  
Systemic Signals

Abstract Sensing of heat, high light (HL), or mechanical injury by a single leaf of a plant results in the activation of different systemic signals that reach systemic tissues within minutes and trigger systemic acquired acclimation (SAA) or systemic wound responses (SWRs), resulting in a heightened state of stress readiness of the entire plant. Among the different signals associated with rapid systemic responses to stress in plants are electric, calcium and reactive oxygen species (ROS) waves. These signals propagate from the stressed or injured leaf to the rest of the plant through the plant vascular bundles, and trigger SWRs and SAA in systemic tissues. However, whether they can propagate through other cell types, and whether or not they are interlinked, remain open questions. Here we report that in response to wounding or heat stress (HS), but not HL stress, the ROS wave can propagate through mesophyll cells of Arabidopsis (Arabidopsis thaliana). Moreover, we show that ROS production by mesophyll cells during these stresses is sufficient to restore SWR and SAA transcript accumulation in systemic leaves, as well as SAA to HS (but not HL). We further show that propagation of the ROS wave through mesophyll cells could contribute to systemic signal integration during HL&HS stress combination. Our findings reveal that the ROS wave can propagate through tissues other than the vascular bundles of plants, and that different stresses can trigger different types of systemic signals that propagate through different cell layers and induce stress-specific systemic responses.

scholarly journals Mesophyll cells mediate systemic reactive oxygen signaling during wounding or heat stress

2021 ◽  
Author(s):  
Sara I. Zandalinas ◽  
Ron Mittler
Keyword(s):  
Heat Stress ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Vascular Bundles ◽  
Transcript Accumulation ◽  
Mesophyll Cells ◽  
Single Leaf ◽  
Cell Layers ◽  
Systemic Responses ◽  
Systemic Signals

ABSTRACTSensing of heat, high light (HL), or mechanical injury by a single leaf of a plant results in the activation of different systemic signals that reach systemic tissues within minutes and trigger systemic acquired acclimation (SAA) or systemic wound responses (SWRs), resulting in a heightened state of stress readiness of the entire plant. Among the different signals associated with rapid systemic responses to stress in plants are electric, calcium and reactive oxygen species (ROS) waves. These signals propagate from the stressed or injured leaf to the rest of the plant through the plant vascular bundles, and trigger SWRs and SAA in systemic tissues. However, whether they can propagate through other cell types, and whether or not they are interlinked, remain open questions. Here we report that in response to wounding or heat stress (HS), but not HL stress, the ROS wave can propagate through mesophyll cells of Arabidopsis thaliana. Moreover, we show that propagation of the ROS wave through mesophyll cells during these stresses is sufficient to restore SWR and SAA transcript accumulation in systemic leaves, as well as SAA to HS (but not HL). We further show that propagation of the ROS wave through mesophyll cells could contribute to systemic signal integration during HL&HS stress combination. Our findings reveal that the ROS wave can propagate through tissues other than the vascular bundles of plants, and that different stresses can trigger different types of systemic signals that propagate through different cell layers and induce stress-specific systemic responses.One-sentence summaryIn addition to vascular bundles, mesophyll cells can mediate the ROS wave during systemic responses to wounding or heat stress in Arabidopsis.

scholarly journals Carbon Metabolism in Developing Soybean Root Nodules: The Role of Carbonic Anhydrase

2000 ◽  
Vol 13 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Nektarios Kavroulakis ◽  
Emanouil Flemetakis ◽  
Georgios Aivalakis ◽  
Panagiotis Katinakis
Keyword(s):  
In Situ Hybridization ◽  
Carbonic Anhydrase ◽  
Root Nodules ◽  
Cell Types ◽  
Nodule Development ◽  
Vascular Bundles ◽  
Transcript Accumulation ◽  
Cortical Cells ◽  
Gene Transcripts

A full-length cDNA clone encoding carbonic anhydrase (CA) was isolated from a soybean nodule cDNA library. In situ hybridization and immunolocalization were performed in order to assess the location of CA transcripts and protein in developing soybean nodules. CA transcripts and protein were present at high levels in all cell types of young nodules, whereas in mature nodules they were absent from the central tissue and were concentrated in cortical cells. The results suggested that, in the earlier stages of nodule development, CA might facilitate the recycling of CO2 while at later stages it may facilitate the diffusion of CO2 out of the nodule system. In parallel, sucrose metabolism was investigated by examination of the temporal and spatial transcript accumulation of sucrose synthase (SS) and phosphoenolpyruvate carboxylase (PEPC) genes, with in situ hybridization. In young nodules, high levels of SS gene transcripts were found in the central tissue as well as in the parenchymateous cells and the vascular bundles, while in mature nodules the levels of SS gene transcripts were much lower, with the majority of the transcripts located in the parenchyma and the pericycle cells of the vascular bundles. High levels of expression of PEPC gene transcripts were found in mature nodules, in almost all cell types, while in young nodules lower levels of transcripts were detected, with the majority of them located in parenchymateous cells as well as in the vascular bundles. These data suggest that breakdown of sucrose may take place in different sites during nodule development.

scholarly journals Four Mutant Alleles Elucidate the Role of the G2 Protein in the Development of C4 and C3 Photosynthesizing Maize Tissues

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 787-797
Author(s):  
Lizzie Cribb ◽  
Lisa N Hall ◽  
Jane A Langdale
Keyword(s):  
Cell Types ◽  
Bundle Sheath ◽  
Primary Role ◽  
Ribulose Bisphosphate Carboxylase ◽  
Sheath Cell ◽  
Mesophyll Cells ◽  
Phenotypic Data ◽  
Bisphosphate Carboxylase ◽  
Bundle Sheath Cell

Abstract Maize leaf blades differentiate dimorphic photosynthetic cell types, the bundle sheath and mesophyll, between which the reactions of C4 photosynthesis are partitioned. Leaf-like organs of maize such as husk leaves, however, develop a C3 pattern of differentiation whereby ribulose bisphosphate carboxylase (RuBPCase) accumulates in all photosynthetic cell types. The Golden2 (G2) gene has previously been shown to play a role in bundle sheath cell differentiation in C4 leaf blades and to play a less well-defined role in C3 maize tissues. To further analyze G2 gene function in maize, four g2 mutations have been characterized. Three of these mutations were induced by the transposable element Spm. In g2-bsd1-m1 and g2-bsd1-s1, the element is inserted in the second intron and in g2-pg14 the element is inserted in the promoter. In the fourth case, g2-R, four amino acid changes and premature polyadenylation of the G2 transcript are observed. The phenotypes conditioned by these four mutations demonstrate that the primary role of G2 in C4 leaf blades is to promote bundle sheath cell chloroplast development. C4 photosynthetic enzymes can accumulate in both bundle sheath and mesophyll cells in the absence of G2. In C3 tissue, however, G2 influences both chloroplast differentiation and photosynthetic enzyme accumulation patterns. On the basis of the phenotypic data obtained, a model that postulates how G2 acts to facilitate C4 and C3 patterns of tissue development is proposed.

scholarly journals TRPM2 Non-Selective Cation Channels in Liver Injury Mediated by Reactive Oxygen Species

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1243
Author(s):  
Eunus S. Ali ◽  
Grigori Y. Rychkov ◽  
Greg J. Barritt
Keyword(s):  
Reactive Oxygen Species ◽  
Liver Injury ◽  
Cell Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Chronic Liver ◽  
Oxygen Species ◽  
Alcoholic Fatty Liver ◽  
Trpm2 Channels

TRPM2 channels admit Ca2+ and Na+ across the plasma membrane and release Ca2+ and Zn2+ from lysosomes. Channel activation is initiated by reactive oxygen species (ROS), leading to a subsequent increase in ADP-ribose and the binding of ADP-ribose to an allosteric site in the cytosolic NUDT9 homology domain. In many animal cell types, Ca2+ entry via TRPM2 channels mediates ROS-initiated cell injury and death. The aim of this review is to summarise the current knowledge of the roles of TRPM2 and Ca2+ in the initiation and progression of chronic liver diseases and acute liver injury. Studies to date provide evidence that TRPM2-mediated Ca2+ entry contributes to drug-induced liver toxicity, ischemia–reperfusion injury, and the progression of non-alcoholic fatty liver disease to cirrhosis, fibrosis, and hepatocellular carcinoma. Of particular current interest are the steps involved in the activation of TRPM2 in hepatocytes following an increase in ROS, the downstream pathways activated by the resultant increase in intracellular Ca2+, and the chronology of these events. An apparent contradiction exists between these roles of TRPM2 and the role identified for ROS-activated TRPM2 in heart muscle and in some other cell types in promoting Ca2+-activated mitochondrial ATP synthesis and cell survival. Inhibition of TRPM2 by curcumin and other “natural” compounds offers an attractive strategy for inhibiting ROS-induced liver cell injury. In conclusion, while it has been established that ROS-initiated activation of TRPM2 contributes to both acute and chronic liver injury, considerable further research is needed to elucidate the mechanisms involved, and the conditions under which pharmacological inhibition of TRPM2 can be an effective clinical strategy to reduce ROS-initiated liver injury.

Immunolocalization of antioxidant enzymes in testis of rams submitted to long-term heat stress

Zygote ◽  
2019 ◽  
Vol 27 (6) ◽  
pp. 432-435
Author(s):  
Thais Rose dos Santos Hamilton ◽  
Gabriela Esteves Duarte ◽  
José Antonio Visintin ◽  
Mayra Elena Ortiz D’Ávila Assumpção
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Heat Stress ◽  
Glutathione Peroxidase ◽  
Cell Types ◽  
Treated Group ◽  
Oxidative Balance ◽  
Testicular Cells

SummaryLong-term heat stress (HS) induced by testicular insulation generates oxidative stress (OS) on the testicular environment; consequently activating antioxidant enzymes such as superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx). The aim of this work was to immunolocalize antioxidant enzymes present in different cells within the seminiferous tubule when rams were submitted to HS. Rams were divided into control (n = 6) and treated group (n = 6), comprising rams subjected to testicular insulation for 240 h. After the testicular insulation period, rams were subjected to orchiectomy. Testicular fragments were submitted to immunohistochemistry for staining against SOD, GR and GPx enzymes. We observed immunolocalization of GPx in more cell types of the testis after HS and when compared with other enzymes. In conclusion, GPx is the main antioxidant enzyme identified in testicular cells in an attempt to maintain oxidative balance when HS occurs.

Developing membrane-derived nanocarriers for ex vivo therapy of homologous breast cancer cells

Nanomedicine ◽  
2021 ◽  
Author(s):  
Muktashree Saha ◽  
Anil P  Bidkar ◽  
Siddhartha S  Ghosh
Keyword(s):  
Breast Cancer ◽  
Reactive Oxygen Species ◽  
Ex Vivo ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Cancer Cell Line ◽  
Cell Types ◽  
Extrusion Process ◽  
Pyrrolidine Dithiocarbamate ◽  
Oxygen Species

Aim: The primary aim of this study was to develop biomimetic nanocarriers for specific homologous targeting of the anticancer drugs ammonium pyrrolidine dithiocarbamate (PDTC) and doxorubicin. Methods: Membranous nanovesicles were synthesized from a breast cancer cell line (MCF7) by syringe extrusion process and were loaded with PDTC and doxorubicin. Besides their abilities for self-homing, the drug loaded nanovesicles showed anti-cell proliferative effects via the generation of reactive oxygen species. Results: The nanovesicles demonstrated efficient internalization via homologous targeting. Delivery of PDTC showed a higher killing effect for homologous cell targeting than other cell types. Experimental results demonstrated increased antiproliferative potency of PDTC, which induced apoptosis via reactive oxygen species generation. Conclusion: The developed membrane-derived nanocarrier is an attractive biocompatible system for ex vivo targeted drug delivery.

Salt stress influence on stomatal and hydraulic conductivity, as well as on the level of aquaporins in leaf cells of barley plants, differing in salt tolerance

Biomics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 280-287
Author(s):  
G.V. Sharipova ◽  
R.S. Ivanov ◽  
L.B. Vysotskaya ◽  
G.R. Akhiyarova
Keyword(s):  
Salt Stress ◽  
Hydraulic Conductivity ◽  
Stomatal Closure ◽  
Immunohistochemical Localization ◽  
Vascular Bundles ◽  
Salt Tolerant ◽  
Mesophyll Cells ◽  
Relationship Of ◽  
Concentration Assessment ◽  
Stress Influence

We studied participation of aquaporins in the regulation of leaf hydraulic conductivity and relationship of hydraulic conductivity with accumulation of ABA and stomatal closure during salt stress. Using the method of immunohistochemical localization we showed that salinity led to greater decline in the level of aquaporins in the region of the vascular leaf bundles of the more salt-tolerant Prairia cultivar, accompanied by a noticeable decrease in hydraulic conductivity of the leaf. In the less salt-tolerant plants of the Mikhailovsky cultivar, significant changes in the level of aquaporins under the influence of salt stress were not found. The degree of decrease in the hydraulic conductivity of the leaf in plants of two cultivars under the influence of salt stress correlated with a decrease in transpiration. Immunohistochemical localization of abscisic acid (ABA) in leaf cells showed that during salt stress this hormone accumulated in leaf mesophyll cells and stomata. The uptake of exogenous hormone from the nutrient solution and its entry into the leaf through the vascular bundles was accompanied by an increase in staining for aquaporins and the hydraulic conductivity of the leaves, which is characteristic of the ABA action. Differences in the localization of exogenous and endogenous hormones were obviously the cause of the opposite directions of changes in hydraulic conductivity: its increase under the influence of an exogenous ABA and a decrease - under the influence of salt stress. ABA concentration assessment in xylem showed the absence of its increase during salt stress, which explains the absence changes of staining for this hormone in the region of the leaf vascular bundles and indicates that accumulation of ABA in a short-term salt stress is not the result of its delivery from the roots, but the result of its synthesis in the shoot itself.

scholarly journals Nimodipine-Dependent Protection of Schwann Cells, Astrocytes and Neuronal Cells from Osmotic, Oxidative and Heat Stress Is Associated with the Activation of AKT and CREB

2019 ◽  
Vol 20 (18) ◽  
pp. 4578 ◽  
Author(s):  
Sandra Leisz ◽  
Sebastian Simmermacher ◽  
Julian Prell ◽  
Christian Strauss ◽  
Christian Scheller
Keyword(s):  
Heat Stress ◽  
Schwann Cells ◽  
Molecular Mechanisms ◽  
Neuroprotective Effect ◽  
Neuronal Cells ◽  
Cell Types ◽  
Stress Conditions ◽  
Cell Culture Supernatant ◽  
Neuroprotective Effects ◽  
Stress Dependent

Clinical and experimental data assumed a neuroprotective effect of the calcium channel blocker nimodipine. However, it has not been proven which neuronal or glial cell types are affected by nimodipine and which mechanisms underlie these neuroprotective effects. Therefore, the aim of this study was to investigate the influence of nimodipine treatment on the in vitro neurotoxicity of different cell types in various stress models and to identify the associated molecular mechanisms. Therefore, cell lines from Schwann cells, neuronal cells and astrocytes were pretreated for 24 h with nimodipine and incubated under stress conditions such as osmotic, oxidative and heat stress. The cytotoxicity was measured via the lactate dehydrogenase (LDH) activity of cell culture supernatant. As a result, the nimodipine treatment led to a statistically significantly reduced cytotoxicity in Schwann cells and neurons during osmotic (p ≤ 0.01), oxidative (p ≤ 0.001) and heat stress (p ≤ 0.05), when compared to the vehicle. The cytotoxicity of astrocytes was nimodipine-dependently reduced during osmotic (p ≤ 0.01), oxidative (p ≤ 0.001) and heat stress (not significant). Moreover, a decreased caspase activity as well as an increased proteinkinase B (AKT) and cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation could be observed after the nimodipine treatment under different stress conditions. These results demonstrate a cell type-independent neuroprotective effect of the prophylactic nimodipine treatment, which is associated with the prevention of stress-dependent apoptosis through the activation of CREB and AKT signaling pathways and the reduction of caspase 3 activity.

The distribution and ultrastructure of chloroplasts in leaves differing in photosynthetic carbon metabolism. I. Wheat, Sorghum, and Aristida (Gramineae)

1969 ◽  
Vol 47 (1) ◽  
pp. 15-21 ◽  
Author(s):  
T. Bisalputra ◽  
W. J. S. Downton ◽  
E. B. Tregunna
Keyword(s):  
Carbon Dioxide ◽  
Bundle Sheath ◽  
Vascular Bundles ◽  
Photosynthetic Pathway ◽  
Low Carbon ◽  
Mesophyll Cells ◽  
Cytological Evidence ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon Metabolism ◽  
High Carbon Dioxide

The ultrastructure of the chlorenchymatous tissues around the vascular bundles of three different types of grass leaves is described. In the temperate grass leaf, as exemplified by wheat, the inner mestom sheath contains proplastids. Normal chloroplasts are found only within the mesophyll cells. Smaller chloroplasts occur in cells of the ill-defined parenchymatic bundle sheath. This type of leaf has the photosynthetic pathway described by Calvin and a high carbon dioxide compensation value. In the tropical grasses, Sorghum and Aristida, the new photosynthetic pathway proposed by Hatch et al. and low carbon dioxide compensation are correlated with development of the parenchymatic bundle sheath. Cytological evidence indicates that cells of the bundle sheath are much more active than the surrounding mesophyll tissue. The specialized chloroplasts of the bundle sheath cells may be responsible for the physiological and biochemical differences between leaves of tropical and temperate grasses.

Leaf Ultrastructure and δ13C Values of Three Seagrasses from the Great Barrier Reef

1976 ◽  
Vol 3 (1) ◽  
pp. 9 ◽  
Author(s):  
ME Doohan ◽  
EH Newcomb
Keyword(s):  
Great Barrier Reef ◽  
Leaf Anatomy ◽  
Co2 Assimilation ◽  
Land Plants ◽  
Vascular Bundles ◽  
Barrier Reef ◽  
Thalassia Hemprichii ◽  
Mesophyll Cells ◽  
Δ13c Values ◽  
Abundant Cytoplasm

Leaf anatomy, ultrastructure and 13C/12C ratios were studied in three species of seagrasses collected on the Great Barrier Reef: Cymodocea rotundata Ehrenb. & Hempr., C. serrulata (R. Br.) Aschers. & Magnus, and Thalassia hemprichii (Ehrenb.) Aschers. Although they belong to two different mono- cotyledonous families, the three species are quite similar in the characteristics studied. Cells of the epidermal layer of the leaves are extremely thick-walled and have abundant cytoplasm with large chloroplasts and numerous mitochondria. The chloroplast-microbody profile ratio is c. 4-5 : 1 and the mitochondrion-microbody ratio 10-15 : 1. The epidermal cells resemble transfer cells in having a pronounced development of ingrowths on the radial walls. The mesophyll cells have thin walls, a large central vacuole and a thin layer of cytoplasm with relatively few organelles. There is no specialization of mesophyll cells around the vascular bundles. The δ13C values for the three sea- grasses range from -6.90, to - 12.40, and thus are characteristic of C4 land plants, although the seagrasses do not conform to the C4 syndrome in leaf anatomy or ultrastructure. It is not possible to place the seagrasses in either the C3, C4 or crassulacean acid metabolism category of land plants, but whether they constitute yet a fourth group with respect to characteristics related to CO2 assimilation is not clear.

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