scholarly journals Ozone uptake at night is more damaging to plants than equivalent day-time flux

Planta ◽  
2021 ◽  
Vol 253 (3) ◽  
Author(s):  
Eleni Goumenaki ◽  
Ignacio González-Fernández ◽  
Jeremy D. Barnes
Keyword(s):  
Relative Sensitivity ◽  
Redox Status ◽  
Wild Relative ◽  
Assimilation Rate ◽  
Regional Models ◽  
Night Time ◽  
Ozone Uptake ◽  
Ozone Fluxes ◽  
Pre Treatment ◽  
Dark Transition

Abstract Main conclusion Plants exposed to equivalent ozone fluxes administered during day-time versus night-time exhibited greater losses in biomass at night and this finding is attributed to night-time depletion of cell wall-localised ascorbate. Abstract The present study employed Lactuca sativa and its closest wild relative, L. serriola, to explore the relative sensitivity of plants to ozone-induced oxidative stress during day-time versus night-time. By controlling atmospheric ozone concentration and measuring stomatal conductance, equivalent ozone uptake into leaves was engineered during day and night, and consequences on productivity and net CO2 assimilation rate were determined. Biomass losses attributable to ozone were significantly greater when an equivalent dose of ozone was taken-up by foliage at night compared to the day. Linkages between ozone impacts and ascorbic acid (AA) content, redox status and cellular compartmentation were probed in both species. Leaf AA pools were depleted by exposure of plants to darkness, and then AA levels in the apoplast and symplast were monitored on subsequent transfer of plants to the light. Apoplast AA appeared to be more affected by light–dark transition than the symplast pool. Moreover, equivalent ozone fluxes administered to leaves with contrasting AA levels resulted in contrasting effects on the light-saturated rate of CO2 assimilation (Asat) in both species. Once apoplast AA content recovered to pre-treatment levels, the same ozone flux resulted in no impacts on Asat. The results of the present investigation reveal that plants are significantly more sensitive to equivalent ozone fluxes taken-up at night compared with those during the day and were consistent with diel shifts in apoplast AA content and/or redox status. Furthermore, findings suggest that some thought should be given to weighing regional models of ozone impacts for extraordinary night-time ozone impacts.

Night-time food restriction modulates the circadian patterns of redox status in rats

2010 ◽  
Vol 41 (1) ◽  
pp. 17-25 ◽  
Author(s):  
M. Jayakumar ◽  
D. Arul ◽  
P. Prahalathan ◽  
P. Subramanian
Keyword(s):  
Food Restriction ◽  
Redox Status ◽  
Night Time ◽  
Circadian Patterns

scholarly journals Interferon production and sensitivity of Semliki Forest virus variants

1964 ◽  
Vol 62 (3) ◽  
pp. 337-349 ◽  
Author(s):  
N. B. Finter
Keyword(s):  
Technical Assistance ◽  
Semliki Forest Virus ◽  
Relative Sensitivity ◽  
Kidney Cells ◽  
Interferon Production ◽  
Predominant Type ◽  
In Series ◽  
Pre Treatment ◽  
Virus Adaptation ◽  
Parallel Growth

Semliki Forest virus was passaged 10 times in series in calf kindly cells, starting with virus passaged in the mouse brain (MB virus). A variant was obtained (termed CK virus). The two viruses were antigenically indistinguishable. When grown on L cells, CK virus formed smaller plaques than MB virus. In parallel growth curve studies in calf kidney cells, a small inoculum of CK virus grew more rapidly and to a higher final titre than a comparable inoculum of MB virus, and usually stimulated production of less interferon. Pre-treatment of cells with calf interferon reduced the growth of both viruses, but especially that of MB virus. The results are considered in relation to the phenomenon of virus adaptation. It is suggested that such differences between the two variants in their relative sensitivity to and production of interferon could have played a part in the emergence of CK virus as the predominant type during serial passages in calf cells.I wish to thank Mr H. Moores and Mr R. Sims for skilful technical assistance.

Administration of Antioxidants in the Infertile Male: When it may have a Beneficial Effect?.

2020 ◽  
Vol 26 ◽  
Author(s):  
Zsolt Kopa ◽  
Marton Keszthelyi ◽  
Nikolaos Sofikitis
Keyword(s):  
Oxidative Stress ◽  
Male Infertility ◽  
Membrane Damage ◽  
Live Birth Rate ◽  
Redox Status ◽  
Antioxidant Systems ◽  
Sperm Function ◽  
Antioxidant Treatment ◽  
Reductive Stress ◽  
Pre Treatment

Background: Reactive Oxygen Species (ROS) are required for intact spermatogenesis and sperm function, but excessive levels will cause oxidative stress, impairing sperms and sperm function due to membrane damage and DNA fragmentation. Objective: Theoretically, antioxidant supplementation may act as a protecting system against free radicals. Since infertile males have higher levels of ROS, nutritional supplements are widely used for protecting sperms. In the recent review authors summarize the most recent data regarding the effect of antioxidant treatment and draw an attention of the limitations of antioxidant use in male infertility. Methods: The recent review gives an update of antioxidant treatment in male infertility. Results: Improvement of sperm parameters was reported in the majority of studies. Comparing different antioxidants versus placebo showed low certainty of evidence with a serious risk of bias, and there is a lack regarding certain doses, pregnancy rate, and live birth rate outcomes. Various clinical studies and randomized control trials reported even negative outcomes. Conflicting findings lead the attention to the study of biochemical features of the oxidant vs. antioxidant equilibrium. Higher exposure to antioxidants will result in „reductive stress”, which has harmful effects on sperm function, moreover can negatively influence embryo development. Reductive stress is as dangerous as oxidative stress and may act as a cause of different human pathologies. Conclusion: An intact balance of oxidant and antioxidant systems is required to normal sperm function. No guideline exists for the antioxidant dose regimen and treatment duration. Overdosing can result in reductive stress, which is also harmful to fertility and can cause several diseases. Assessment of the pre-treatment redox status can be recommended before the administration of exogenous antioxidants.

scholarly journals Predicting and partitioning ozone fluxes to maize crops from sowing to harvest: the Surfatm-O<sub>3</sub> model

2011 ◽  
Vol 8 (10) ◽  
pp. 2869-2886 ◽  
Author(s):  
P. Stella ◽  
E. Personne ◽  
B. Loubet ◽  
E. Lamaud ◽  
E. Ceschia ◽  
...  
Keyword(s):  
Total Ozone ◽  
Terrestrial Ecosystems ◽  
Bare Soil ◽  
Climatic Conditions ◽  
Night Time ◽  
Entire Study ◽  
Ozone Deposition ◽  
Cropping Season ◽  
Stomatal Flux ◽  
Ozone Fluxes

Abstract. Terrestrial ecosystems represent a major sink for ozone (O3) and also a critical control of tropospheric O3 budget. However, due to its deleterious effects, plant functioning is affected by the ozone absorbed. It is thus necessary to both predict total ozone deposition to ecosystems and partition the fluxes in stomatal and non-stomatal pathways. The Surfatm-O3 model was developed to predict ozone deposition to agroecosystems from sowing to harvest, taking into account each deposition pathways during bare soil, growth, maturity, and senescence periods. An additional sink was added during senescence: stomatal deposition for yellow leaves, not able to photosynthesise but transpiring. The model was confronted to measurements performed over three maize crops in different regions of France. Modelled and measured fluxes agreed well for one dataset for any phenological stage, with only 4% difference over the whole cropping season. A larger discrepancy was found for the two other sites, 15% and 18% over the entire study period, especially during bare soil, early growth and senescence. This was attributed to site-specific soil resistance to ozone and possible chemical reactions between ozone and volatile organic compounds emitted during late senescence. Considering both night-time and daytime conditions, non-stomatal deposition was the major ozone sink, from 100% during bare soil period to 70–80% on average during maturity. However, considering only daytime conditions, especially under optimal climatic conditions for plant functioning, stomatal flux could represent 75% of total ozone flux. This model could improve estimates of crop yield losses and projections of tropospheric ozone budget.

scholarly journals Predicting and partitioning ozone fluxes to maize crops from sowing to harvest: the Surfatm-O<sub>3</sub> model

2011 ◽  
Vol 8 (4) ◽  
pp. 6701-6741
Author(s):  
P. Stella ◽  
E. Personne ◽  
B. Loubet ◽  
E. Lamaud ◽  
E. Ceschia ◽  
...  
Keyword(s):  
Total Ozone ◽  
Terrestrial Ecosystems ◽  
Bare Soil ◽  
Climatic Conditions ◽  
Night Time ◽  
Entire Study ◽  
Ozone Deposition ◽  
Cropping Season ◽  
Stomatal Flux ◽  
Ozone Fluxes

Abstract. Terrestrial ecosystems represent a major sink for ozone (O3) and also a critical control of tropospheric O3 budget. However, due to its deleterious effects, plant functioning is affected by the ozone absorbed. It is thus necessary to both predict total ozone deposition to ecosystems and partition the fluxes in stomatal and non-stomatal pathways. The Surfatm-O3 model was developed to predict ozone deposition to agroecosystems from sowing to harvest, taking into account each deposition pathways during bare soil, growth, maturity, and senescence periods. An additional sink was added during senescence: stomatal deposition for yellow leaves, not able to photosynthesise but transpiring. The model was confronted to measurements performed over three maize crops in different regions of France. Modelled and measured fluxes agreed well for one dataset for any phenological stage, with only 3 % difference over the whole cropping season. A larger discrepancy was found for the two other sites, 16 % and 19 % over the entire study period, especially during bare soil, early growth and senescence. This was attributed to site-specific soil resistance to ozone and possible chemical reactions between ozone and volatile organic compounds emitted during late senescence. Considering both night-time and daytime conditions, non-stomatal deposition was the major ozone sink, from 100 % during bare soil period to 70–80 % on average during maturity. However, considering only daytime conditions, especially under optimal climatic conditions for plant functioning, stomatal flux could represent 75 % of total ozone flux. This model could improve estimates of crop yield losses and projections of tropospheric ozone budget.

scholarly journals Improved sapflow methodology reveals considerable night-time ozone uptake by Mediterranean species

2009 ◽  
Vol 6 (12) ◽  
pp. 3151-3162 ◽  
Author(s):  
S. Mereu ◽  
G. Gerosa ◽  
A. Finco ◽  
L. Fusaro ◽  
B. Muys ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Sap Flow ◽  
Woody Species ◽  
Percentage Increase ◽  
Mediterranean Species ◽  
Night Time ◽  
Ozone Uptake ◽  
Daily Uptake ◽  
Slow Flows ◽  
Leaf Level

Abstract. Due to the evident tropospheric ozone impact on plant productivity, an accurate ozone risk assessment for the vegetation has become an issue. There is a growing evidence that ozone stomatal uptake may also take place at night and that the night-time uptake may be more damaging than diurnal uptake. Estimation of night-time uptake in the field is complicated because of instrumental difficulties. Eddy covariance technology is not always reliable because of the low turbulence at night. Leaf level porometry is defective at relative humidity above 70% which often takes place at night. Improved sap flow technology allows to estimate also slow flows that usually take place at night and hence may be, at present, the most trustworthy technology to measure night-time transpiration and hence to derive canopy stomatal conductance and ozone uptake at night. Based on micrometeorological data and the sap flow of three Mediterranean woody species, the night-time ozone uptake of these species was evaluated during a summer season as drought increased. Night-time ozone uptake was from 10% to 18% of the total daily uptake when plants were exposed to a weak drought, but increased up to 24% as the drought became more pronounced. The percentage increase is due to a stronger reduction of diurnal stomatal conductance than night-time stomatal conductance.

scholarly journals Night-time ozone uptake by Mediterranean species

2009 ◽  
Vol 6 (1) ◽  
pp. 2007-2038
Author(s):  
S. Mereu ◽  
A. Finco ◽  
G. Gerosa ◽  
L. Fusaro ◽  
B. Muys ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Sap Flow ◽  
Woody Species ◽  
Summer Season ◽  
Percentage Increase ◽  
Mediterranean Species ◽  
Night Time ◽  
Ozone Uptake ◽  
Slow Flows ◽  
Leaf Level

Abstract. Due to the evident tropospheric ozone impact on plant productivity, an accurate ozone risk assessment for the vegetation has become an issue. There is a growing evidence that ozone stomatal uptake may also take place at night and that the night-time uptake may be more damaging than diurnal uptake. Estimation of night-time uptake in the field is complicated because of instrumental difficulties. Eddy covariance technology is not always reliable because of the low turbulence at night. Leaf level porometry is defective at relative humidity above 70% which often takes place at night. Improved sap flow technology allows to estimate also slow flows that usually take place at night and hence may be, at present, the most trustworthy technology to measure night-time transpiration and hence to derive canopy stomatal conductance and ozone uptake at night. Based on micrometeorological data and the sap flow of three Mediterranean woody species, the night-time ozone uptake of these species was evaluated during a summer season as drought increased. Night-time ozone uptake was 10% of the total when plants were exposed to a weak drought, but increased up to 24% as the drought became more pronounced. The percentage increase is due to a stronger reduction of diurnal stomatal conductance than night-time stomatal conductance.

scholarly journals Evaluating stomatal ozone fluxes in WRF-Chem: Comparing ozone uptake in Mediterranean ecosystems

2016 ◽  
Vol 143 ◽  
pp. 237-248 ◽  
Author(s):  
J.H. Rydsaa ◽  
F. Stordal ◽  
G. Gerosa ◽  
A. Finco ◽  
Ø. Hodnebrog
Keyword(s):  
Mediterranean Ecosystems ◽  
Ozone Uptake ◽  
Ozone Fluxes

scholarly journals Ischaemic and pharmacological preconditionings protect liver via adenosine and redox status following hepatic ischaemia/reperfusion in rats

2008 ◽  
Vol 115 (2) ◽  
pp. 69-77 ◽  
Author(s):  
Hussam H. Ajamieh ◽  
Eduardo Candelario-Jalil ◽  
Olga Sonia León Fernández ◽  
Alexander L Gerbes
Keyword(s):  
Oxidative Stress ◽  
Body Weight ◽  
Redox Status ◽  
Lung Damage ◽  
Protective Effects ◽  
Sod Activity ◽  
Ischaemia Reperfusion ◽  
Pre Treatment ◽  
Endogenous Antioxidant

Although IPC (ischaemic preconditioning) is considered as a protective strategy in HI/R (hepatic ischaemia/reperfusion), the mechanisms for this effect have not been fully elucidated. In the present study we investigate whether PPC (pharmacological preconditioning) by transient activation of A1R (adenosine A1 receptor) protects against long-term HI/R and whether the protective effects of IPC depend on A1R activation and whether both preconditionings affect remote organs. Wistar rats underwent IPC and long-term HI/R. Another set of animals were pharmacologically preconditioned with the A1R-agonist CCPA [2-chloro-N6-cyclopentyladenosine; 0.1 mg/kg of body weight, i.p. (intraperitoneally)] 24 h before HI/R. In other groups, rats received an A1R-antagonist, DPCPX (1,3-dipropyl-8-cyclopentylxanthine; 0.1 mg/kg of body weight, i.p.) 24 h before HI/R. Hepatic damage was evaluated by transaminase [AST (aspartate transaminase), ALT (alanine transaminase)] release; inflammation was assessed by hepatic MPO (myeloperoxidase) and serum TNFα (tumour necrosis factor α) and NO; oxidative stress was estimated by MDA (malondialdehyde) and 4-HDA (4-hydroxyalkenals), SOD (superoxide dismutase) activity, GSH and ADA (adenosine deaminase) as adenosine metabolism. Both preconditionings protected liver and lung against HI/R as indicated by the reduction in transaminases, MPO, MDA+4-HDA, NO, TNFα and ADA activity as compared with HI/R (P<0.05). However, pre-treatment with DPCPX abolished the protective effects of IPC and PPC. Preconditionings induced a significant increase in hepatic MnSOD (manganese SOD) activity and NO generation compared with the sham group, and this activity was abolished by DPCPX pre-treatment. A1R activation induced hepatic delayed preconditioning and blockade of A1R abolished hepatic IPC. IPC, as well as PPC, were able to prevent lung damage. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation.

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