scholarly journals Long-Term m5C Methylome Dynamics Parallel Phenotypic Adaptation in the Cyanobacterium Trichodesmium

2020 ◽  
Author(s):  
Nathan G Walworth ◽  
Michael D Lee ◽  
Egor Dolzhenko ◽  
Fei-Xue Fu ◽  
Andrew D Smith ◽  
...  
Keyword(s):  
Global Change ◽  
Co2 Concentration ◽  
Adaptive Responses ◽  
Short Term ◽  
Modern Biology ◽  
High Co2 ◽  
Biological Responses ◽  
Evolution Experiment ◽  
Ambient Co2

Abstract A major challenge in modern biology is understanding how the effects of short-term biological responses influence long-term evolutionary adaptation, defined as a genetically determined increase in fitness to novel environments. This is particularly important in globally important microbes experiencing rapid global change, due to their influence on food webs, biogeochemical cycles, and climate. Epigenetic modifications like methylation have been demonstrated to influence short-term plastic responses, which ultimately impact long-term adaptive responses to environmental change. However, there remains a paucity of empirical research examining long-term methylation dynamics during environmental adaptation in nonmodel, ecologically important microbes. Here, we show the first empirical evidence in a marine prokaryote for long-term m5C methylome modifications correlated with phenotypic adaptation to CO2, using a 7-year evolution experiment (1,000+ generations) with the biogeochemically important marine cyanobacterium Trichodesmium. We identify m5C methylated sites that rapidly changed in response to high (750 µatm) CO2 exposure and were maintained for at least 4.5 years of CO2 selection. After 7 years of CO2 selection, however, m5C methylation levels that initially responded to high-CO2 returned to ancestral, ambient CO2 levels. Concurrently, high-CO2 adapted growth and N2 fixation rates remained significantly higher than those of ambient CO2 adapted cell lines irrespective of CO2 concentration, a trend consistent with genetic assimilation theory. These data demonstrate the maintenance of CO2-responsive m5C methylation for 4.5 years alongside phenotypic adaptation before returning to ancestral methylation levels. These observations in a globally distributed marine prokaryote provide critical evolutionary insights into biogeochemically important traits under global change.

N-Acetylcysteine’s Attenuation of Fatigue After Repeated Bouts of Intermittent Exercise: Practical Implications for Tournament Situations

2011 ◽  
Vol 21 (6) ◽  
pp. 451-461 ◽  
Author(s):  
James N. Cobley ◽  
Chris McGlory ◽  
James P. Morton ◽  
Graeme L. Close
Keyword(s):  
Side Effects ◽  
Muscle Fatigue ◽  
Intermittent Exercise ◽  
Adaptive Responses ◽  
Short Term ◽  
Treatment Dose ◽  
Gastrointestinal Side Effects ◽  
Matched Design ◽  
Over Time

Production of reactive oxygen species (ROS) during muscle contractions is associated with muscle fatigue and damage in the short term and adaptive responses in the long term. When adaptation is inconsequential acute antioxidant supplementation may be able to attenuate muscle fatigue and damage to enhance performance. This study aimed to determine the effects of acute oral N-acetylcysteine (NAC) supplementation on Yo-Yo Intermittent Recovery Test Level 1 (YIRT-L1) performance after repeated bouts of damaging intermittent exercise. In a pair-matched design, 12 recreationally trained men engaged in 6 d of either NAC (n = 6) or placebo (n = 6) supplementation. After a treatment-loading day, participants completed 3 testing sessions, on alternating days, consisting of a preexercise isokinetic dynamometry (IKD) test, a damaging intermittent-exercise protocol, YIRT-L1, and a postexercise IKD test. Another IKD test was completed on the 2 intervening d. NAC treatment resulted in a significant preservation of YIRT-L1 performance (p ≤ .0005). IKD performance significantly deteriorated over time at all contraction speeds, and this deterioration was not influenced by treatment group. Plasma creatine kinase values increased significantly over time (p = .002) and were significantly greater in the NAC group than in the placebo group (p = .029). NAC induced mild gastrointestinal side effects. NAC supplementation may be a useful strategy to enhance performance during short-term competitive situations when adaption is inconsequential. Titration studies to elucidate a treatment dose that enhances performance without inducing side effects are now required.

scholarly journals No evidence for short-term evolutionary response to a warming environment in Drosophila

2021 ◽  
Author(s):  
Marta A. Santos ◽  
Ana Carromeu-Santos ◽  
Ana S. Quina ◽  
Mauro Santos ◽  
Margarida Matos ◽  
...  
Keyword(s):  
Thermal Response ◽  
Reaction Norm ◽  
Thermal Reaction ◽  
Historical Background ◽  
Adaptive Responses ◽  
Short Term ◽  
Warming Scenario ◽  
Evolutionary Response ◽  
Evolution Experiment ◽  
Global Warming Scenario

AbstractAdaptive evolution is key in mediating responses to climate change. Such evolution will expectedly lead to changes in the populations’ thermal reaction norm and improve their ability to cope with stressful conditions. Conversely, constraints of different nature might limit the adaptive response. Here, we test these expectations by performing a real-time evolution experiment in historically differentiated Drosophila subobscura populations. We address the phenotypic changes of flies evolving for nine generations in a daily fluctuating environment with average constant temperature, or a warming environment with increasing average and amplitude temperature across generations. Our results showed that (1) evolution under a global warming scenario has not led, so far, to a noticeable change in the thermal response; (2) historical background appears to be affecting the responses of populations under the warming environment, particularly at higher temperatures; (3) thermal reaction norms are trait-dependent: while lifelong exposure to low temperature decreases fecundity and productivity but not viability, high temperature causes negative transgenerational effects on productivity and viability, even though fecundity remains high. These findings raise concerns about the short-term efficiency of adaptive responses to the current changing climate.

Plant respiration in productivity models: conceptualisation, representation and issues for global terrestrial carbon-cycle research

2003 ◽  
Vol 30 (2) ◽  
pp. 171 ◽  
Author(s):  
Roger M. Gifford
Keyword(s):  
Global Change ◽  
Temperature Response ◽  
Co2 Concentration ◽  
Carbon Accounting ◽  
Short Term ◽  
Complex Process ◽  
C Cycle ◽  
Terrestrial Carbon Cycle ◽  
Global Change Research ◽  
Plant Respiration

Plant respiratory regulation is too complex for a mechanistic representation in current terrestrial productivity models for carbon accounting and global change research. Accordingly, simpler approaches that attempt to capture the essence of respiration are commonly adopted. Several approaches have been used in the literature: respiration may be embedded implicitly in growth algorithms; assumed values for specific respiration rates may be adopted; respiration may be calculated in terms of growth and maintenance components; conservatism in the ratio of respiration to photosynthesis (R : P) may be assumed; or a more complex process or residual approach may be adopted. Review of this literature suggests that the assumption of conservative R : P ratio is an effective and practicable approach in the context of C-cycle modelling for global change research and documentation, requiring minimal ecosystem-specific data on respiration.Some long-standing controversies in respiration are now becoming resolved. The apparently wasteful process of cyanide-resistant respiration by the alternative oxidase may not be wasteful, as it is thought to be involved in protecting the plant from 'reactive oxygen species'. It is now clear that short-term respiratory response coefficients of plants (e.g. the Q10) do not predict their long-term temperature response. A new experimental approach suggests that leaf respiration is not suppressed by light as previously thought. Careful experiments, taking account of several proposed measurement artefacts, indicate that plant respiration is not suppressed by elevated CO2 concentration in a short-term reversible way.

Stomatal Limitation of Photosynthesis in Abscisic Acid-Treated and in Water-Stressed Leaves Measured at Elevated CO2

1988 ◽  
Vol 15 (4) ◽  
pp. 495 ◽  
Author(s):  
SP Robinson ◽  
WJR Grant ◽  
BR Loveys
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Quantum Yield ◽  
Oxygen Evolution ◽  
Stomatal Closure ◽  
Co2 Concentration ◽  
Assimilation Rate ◽  
High Co2 ◽  
Co2 Concentrations ◽  
Ambient Co2

Feeding 10-5M (�)-abscisic acid (ABA) via the petioles of detached leaves of apricot (Prunus armeniaca) or sunflower (Helianthus annuus) decreased stomatal conductance and assimilation rate but not the calculated intercellular CO2 concentration (Ci) suggesting non-stomatal as well as stomatal inhibition of photosynthesis. Evidence for non-stomatal inhibition was not observed in spinach (Spinacia oleracea). There was no significant decrease in rates of electron transport nor ribulosebisphosphate carboxylase (Rubisco) activity in intact chloroplasts isolated from ABA-treated sunflower leaves. Oxygen evolution by leaf discs with 3% CO2 in the gas phase was inhibited in ABA- treated sunflower and apricot leaves but not in spinach; the inhibition was only half as great as the inhibition of assimilation rate at ambient CO2. The quantum yield of oxygen evolution decreased in ABA-treated sunflower leaves in proportion to the decrease in the light-saturated rate. There was no significant difference in room temperature chlorophyll fluorescence of ABA-treated leaves compared to controls. Stomatal conductance of sunflower leaves decreased by more than 90% when the CO2 concentration was increased from 340 ppm to 1000 ppm but at much higher CO2 concentrations the stomata appeared to reopen. Stomatal conductance at 2-3% CO2 (20 000-30 000 ppm) was 50% that at ambient CO2. This reopening of stomata at high CO2 was inhibited in previously water-stressed or ABA-treated plants. In unstressed leaves, the maximum rate of oxygen evolution occurred at 0.5-2% CO2 but in ABA-treated leaves 10-15% CO2 was required for maximum rates. It is suggested that stomatal closure may limit photosynthesis in ABA-treated or previously water-stressed leaves even at the relatively high CO2 concentrations normally used in the leaf disc oxygen electrode. The inhibition of photosynthesis by ABA is largely overcome at saturating CO2. The apparent non-stomatal inhibition suggested by gas exchange measurements and the decreased quantum yield could be explained by patchy stomatal closure in response to ABA.

scholarly journals PHOTOSYNTHESIS OF BIRCH TAXA (Betula L.) UNDER VARIED IRRADIANCE AND CO2 CONCENTRATION

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 882e-883
Author(s):  
Mengmeng Gu ◽  
Curt R. Rom ◽  
James A. Robbins ◽  
Hyun-Sug Choi
Keyword(s):  
Response Curve ◽  
Light Response ◽  
Co2 Concentration ◽  
Betula Alleghaniensis ◽  
Light Response Curve ◽  
Deciduous Species ◽  
Exchange System ◽  
High Co2 ◽  
Gas Exchange System ◽  
Ambient Co2

The genus Betula consists of approximately 50 deciduous species throughout northern hemisphere. Net CO2 assimilation ([A]) of four birch taxa (Betula alleghaniensis Britton, B. davurica Pall., B. nigra L. `Heritage', and B. papyrifera Marsh.) was measured with a portable gas exchange system, CIRAS-I. Light was increased from 0 to 2000 μmol· m-2·s-1 at increments of 25, 50, 100, 250, 500, 750, 1000, 1250, 1500, 1750, 2000 μmol·m–2·s–1 to create an [A] light-response curve. CO2 concentration was gradually increased to 1100 ppm in increments 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 ppm to create an [A]-Ca (ambient CO2) curve. B. davurica had significantly higher potential A capacity than the other taxa under high CO2 conditions. Betula nigra `Heritage' had the highest carboxylation efficiency among four taxa. B. davurica and B. nigra `Heritage', had higher [A] when ambient CO2 is 0ppm. Betula davurica and B. nigra `Heritage', had higher light-saturated rate of gross [A] than B. alleghaniensis and B. papyrifera.

scholarly journals Ageing via sexual perception is a by-product of male adaptive plasticity inDrosophila melanogaster

2021 ◽  
Author(s):  
Quentin Corbel ◽  
Manuel Serra ◽  
Roberto García-Roa ◽  
Pau Carazo
Keyword(s):  
Adaptive Plasticity ◽  
Lifetime Reproductive Success ◽  
Environmental Cues ◽  
Average Increase ◽  
Adaptive Responses ◽  
Short Term ◽  
Wide Range ◽  
Sexual Perception ◽  
Opportunity For Selection

ABSTRACTSensory perception of environmental cues can dramatically modulate ageing across distant taxa. For example, maleDrosophila melanogasterage faster if they perceive female cues but fail to mate (ageing via sexual perception). This finding has been a breakthrough for our understanding of the mechanisms of ageing, yet we ignore how and why such responses have evolved. Here, we usedD. melanogasterto ask whether ageing via sexual perception may be a by-product of plastic adaptive responses to female cues, and found that while long-term sexual perception leads to reproductive costs, short-term perception increases male lifetime reproductive success in a competitive environment. Simulations under a wide range of socio-sexual and demographic scenario suggest that such plasticity as a response to sexual perception might be a widespread strategy in nature. Finally, we show that sexual perception can significantly magnify sexual selection (15-27% average increase in the opportunity for selection).

Photosynthetic acclimation to elevated CO2 concentration in a sweet pepper (Capsicum annuum) crop under Mediterranean greenhouse conditions: influence of the nitrogen source and salinity

2017 ◽  
Vol 44 (6) ◽  
pp. 573 ◽  
Author(s):  
Manuel E. Porras ◽  
Pilar Lorenzo ◽  
Evangelina Medrano ◽  
María J. Sánchez-González ◽  
Ginés Otálora-Alcón ◽  
...  
Keyword(s):  
Capsicum Annuum ◽  
Elevated Co2 ◽  
Nutrient Solution ◽  
Co2 Enrichment ◽  
Co2 Concentration ◽  
Sweet Pepper ◽  
Elevated Co2 Concentration ◽  
High Co2 ◽  
High Co2 Concentration

In many plant species, long-term exposure to elevated CO2 concentration results in a reduction in photosynthetic capacity, known as acclimation. This process is mainly explained by a feedback inhibition mechanism. The supply of a fraction of the nitrogen (N) in the nutrient solution as NH4+ can play an important role in the maintenance of photosynthetic activity and could mitigate the acclimation process. The aims of the present work were to study the photosynthetic response of sweet pepper (Capsicum annuum L.) to CO2 enrichment in Mediterranean greenhouse conditions, throughout the crop growth cycle and to evaluate the supply of NH4+ in the nutrient solution as a strategy to enhance the long-term response to CO2 at different levels of salinity. The experiment was conducted in two identical greenhouses: one with CO2 enrichment according to the ventilation, maintaining a high concentration when the vents were closed and a near-atmospheric level when the vents were open and one without. Sweet pepper plants were grown in both greenhouses, being irrigated with two levels of water salinity and two N sources: (i) NO3– and (ii) NO3– plus NH4+. A reduction in the response of photosynthesis to high CO2 concentration was found in the enriched plants after 135 days of CO2 supply, with respect to the reference plants. The leaf photosynthesis rate measured at high CO2 concentration showed a closer relationship with the leaf N concentration than the non-structural carbohydrate concentration. The relative yield gain of the CO2-enriched plants progressively decreased after reaching a maximum value; this was probably associated with the photosynthetic acclimation process. This decrease was delayed by the use of NH4+ in the nutrient solution at low salinity. Knowledge of the crop phase when acclimation to high CO2 concentration occurs can be the basis for deciding when to impose an early cessation of CO2 application, as a strategy to improve the economic efficiency of CO2 supply in Mediterranean conditions.

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