scholarly journals The Role of Ethylene in the Inhibition of Rooting under Low Oxygen Tensions

1989 ◽  
Vol 89 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Hillel Soffer ◽  
Shimon Mayak ◽  
David W. Burger ◽  
Michael S. Reid
Keyword(s):  
Low Oxygen ◽  
Oxygen Tensions

scholarly journals MNRR1, a Biorganellar Regulator of Mitochondria

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Lawrence I. Grossman ◽  
Neeraja Purandare ◽  
Rooshan Arshad ◽  
Stephanie Gladyck ◽  
Mallika Somayajulu ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Neurodegenerative Diseases ◽  
Family Members ◽  
Unusual Property ◽  
Promoter Element ◽  
Low Oxygen ◽  
Oxidative Stresses ◽  
Graded Response ◽  
Oxygen Tensions

The central role of energy metabolism in cellular activities is becoming widely recognized. However, there are many gaps in our knowledge of the mechanisms by which mitochondria evaluate their status and call upon the nucleus to make adjustments. Recently, a protein family consisting of twin CX9C proteins has been shown to play a role in human pathophysiology. We focus here on two family members, the isoforms CHCHD2 (renamed MNRR1) and CHCHD10. The better studied isoform, MNRR1, has the unusual property of functioning in both the mitochondria and the nucleus and of having a different function in each. In the mitochondria, it functions by binding to cytochromecoxidase (COX), which stimulates respiration. Its binding to COX is promoted by tyrosine-99 phosphorylation, carried out by ABL2 kinase (ARG). In the nucleus, MNRR1 binds to a novel promoter element inCOX4I2and itself, increasing transcription at 4% oxygen. We discuss mutations in both MNRR1 and CHCHD10 found in a number of chronic, mostly neurodegenerative, diseases. Finally, we propose a model of a graded response to hypoxic and oxidative stresses, mediated under different oxygen tensions by CHCHD10, MNRR1, and HIF1, which operate at intermediate and very low oxygen concentrations, respectively.

Vasoactivity of S-nitrosohemoglobin: role of oxygen, heme, and NO oxidation states

Blood ◽  
2003 ◽  
Vol 101 (11) ◽  
pp. 4408-4415 ◽  
Author(s):  
Jack H. Crawford ◽  
C. Roger White ◽  
Rakesh P. Patel
Keyword(s):  
Nitrogen Monoxide ◽  
No Oxidation ◽  
Oxidation States ◽  
Low Oxygen ◽  
Independent Manner ◽  
No Donor ◽  
Oxygen Tensions ◽  
Isolated Rat

Abstract The mechanisms by which S-nitrosohemoglobin (SNOHb) stimulates vasodilation are unclear and underlie the controversies surrounding the proposal that this S-nitrosothiol modulates blood flow in vivo. Among the mechanistic complexities are the nature of vasoactive species released from SNOHb and the role heme and oxygen play in this process. This is important to address since hemoglobin inhibits NO-dependent vasodilation. We compared the vasodilatory properties of distinct oxidation and ligation states of SNOHb at different oxygen tensions. The results show that SNOHb in the oxygenated state (SNOoxyHb) is significantly less efficient than SNOHb in the ferric or met oxidation state (SNOmetHb) at stimulating relaxation of isolated rat aortic rings. Using pharmacologic approaches to modulate nitrogen monoxide radical (·NO)–dependent relaxation, our data suggest that SNOoxyHb promotes vasodilation in a ·NO-independent manner. In contrast, both SNOmetHb and S-nitrosoglutathione (GSNO), a putative intermediate in SNOHb reactivity, elicit vasodilation in a ·NO-dependent process. Consistent with previous observations, an increase in sensitivity of SNOHb vasodilation at low oxygen tensions also was observed. However, this was not exclusive for this protein but applied to a range of nitrosovasodilators (including a ·NO donor [DeaNonoate], an S-nitrosothiol [GSNO], and the nitroxyl anion donor, Angelis salt). This suggests that oxygen-dependent modulation of SNOHb vasoactivity does not occur by controlling the allosteric state of Hb but is a property of vessel responsiveness to nitrosovasodilators at low oxygen tensions.

scholarly journals Waterlogging-Stress-Responsive LncRNAs, Their Regulatory Relationships with MiRNAs and Target Genes in Cucumber (Cucumis sativus L.)

2021 ◽  
Vol 22 (15) ◽  
pp. 8197
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Adela Adamus ◽  
Małgorzata Czernicka
Keyword(s):  
Target Genes ◽  
Recovery Period ◽  
Sufficient Information ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Cucumis Sativus L ◽  
Waterlogging Stress ◽  
Non Coding Rna

Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber.

Sensitivity of malaria parasites to nitric oxide at low oxygen tensions

The Lancet ◽  
1998 ◽  
Vol 351 (9116) ◽  
pp. 1630 ◽  
Author(s):  
AW Taylor-Robinson ◽  
M Looker
Keyword(s):  
Nitric Oxide ◽  
Low Oxygen ◽  
Malaria Parasites ◽  
Oxygen Tensions

scholarly journals NADPH oxidase-derived ROS and the regulation of pulmonary vessel tone

2012 ◽  
Vol 302 (11) ◽  
pp. H2166-H2177 ◽  
Author(s):  
G. Frazziano ◽  
H. C. Champion ◽  
P. J. Pagano
Keyword(s):  
Oxygen Tension ◽  
Vascular Tone ◽  
Systemic Circulation ◽  
Oxygen Species ◽  
Partial Pressure Of Oxygen ◽  
Low Oxygen ◽  
Key Factors ◽  
Pulmonary Vessel ◽  
Major Emphasis

Pulmonary vessel constriction results from an imbalance between vasodilator and vasoconstrictor factors released by the endothelium including nitric oxide, endothelin, prostanoids, and reactive oxygen species (ROS). ROS, generated by a variety of enzymatic sources (such as mitochondria and NADPH oxidases, a.k.a. Nox), appear to play a pivotal role in vascular homeostasis, whereas elevated levels effect vascular disease. The pulmonary circulation is very sensitive to changes in the partial pressure of oxygen and differs from the systemic circulation in its response to this change. In fact, the pulmonary vessels contract in response to low oxygen tension, whereas systemic vessels dilate. Growing evidence suggests that ROS production and ROS-related pathways may be key factors that underlie this differential response to oxygen tension. A major emphasis of our laboratory is the role of Nox isozymes in cardiovascular disease. In this review, we will focus our attention on the role of Nox-derived ROS in the control of pulmonary vascular tone.

Role of oxygen in autoregulation of blood flow in isolated vessels

1964 ◽  
Vol 206 (5) ◽  
pp. 951-954 ◽  
Author(s):  
Oliver Carrier ◽  
James R. Walker ◽  
Arthur C. Guyton
Keyword(s):  
Blood Flow ◽  
Normal Level ◽  
Constant Pressure ◽  
Constant Flow ◽  
Average Increase ◽  
Flow Conditions ◽  
Low Oxygen ◽  
Local Blood Flow ◽  
Initial Flow

The role of oxygen in control of local blood flow was investigated in isolated arterial segments 1 cm in length and 0.5–1.0 mm in diameter by perfusion with blood of various Po2 levels. A decrease in vascular resistance always occurred when the Po2 was lowered and an increase occurred when it was raised. In 20 vessels, using constant-pressure perfusion, an average increase in conductance of 2.38 times normal level was obtained when the Po2 was lowered from 100 to 30 mm Hg. When this datum was plotted according to initial flow, the smaller vessels gave the greatest response to low oxygen (2.73 times normal; sem ± 0.15), whereas the largest gave the least (1.76 times normal; sem ± 0.10). Forty-three vessels perfused under constant-flow conditions gave results which were consistent with and confirmed the constant-pressure results. In all of these experiments pH, Pco2, and temperature were monitored and kept at physiological levels. The results indicate that oxygen could well be a factor in the autoregulation of blood flow.

Gloxy: An oxygen-sensitive coal for accurate measurement of low oxygen tensions in biological systems

1997 ◽  
Vol 38 (1) ◽  
pp. 48-58 ◽  
Author(s):  
Philip E. James ◽  
Oleg Y. Grinberg ◽  
Fuminori Goda ◽  
Tomasz Panz ◽  
Julia A. O'Hara ◽  
...  
Keyword(s):  
Biological Systems ◽  
Low Oxygen ◽  
Oxygen Sensitive ◽  
Oxygen Tensions

scholarly journals The role of biology in planetary evolution: cyanobacterial primary production in low-oxygen Proterozoic oceans

2015 ◽  
Vol 18 (2) ◽  
pp. 325-340 ◽  
Author(s):  
Trinity L. Hamilton ◽  
Donald A. Bryant ◽  
Jennifer L. Macalady
Keyword(s):  
Primary Production ◽  
Low Oxygen ◽  
Planetary Evolution

scholarly journals The Steady-State Transport of Oxygen through Hemoglobin Solutions

1966 ◽  
Vol 49 (4) ◽  
pp. 663-679 ◽  
Author(s):  
K. H. Keller ◽  
S. K. Friedlander
Keyword(s):  
Diffusion Coefficient ◽  
Brownian Motion ◽  
Steady State ◽  
Effective Diffusion ◽  
Close Correlation ◽  
Oxygen Electrode ◽  
Low Oxygen ◽  
Diffusion Rates ◽  
Oxygen Tensions ◽  
Diffusion Coefficient Of Oxygen

The steady-state transport of oxygen through hemoglobin solutions was studied to identify the mechanism of the diffusion augmentation observed at low oxygen tensions. A novel technique employing a platinum-silver oxygen electrode was developed to measure the effective diffusion coefficient of oxygen in steady-state transport. The measurements were made over a wider range of hemoglobin and oxygen concentrations than previously reported. Values of the Brownian motion diffusion coefficient of oxygen in hemoglobin solution were obtained as well as measurements of facilitated transport at low oxygen tensions. Transport rates up to ten times greater than ordinary diffusion rates were found. Predictions of oxygen flux were made assuming that the oxyhemoglobin transport coefficient was equal to the Brownian motion diffusivity which was measured in a separate set of experiments. The close correlation between prediction and experiment indicates that the diffusion of oxyhemoglobin is the mechanism by which steady-state oxygen transport is facilitated.

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