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Proceedings. Biological Sciences Mar 2019Reef-building corals typically live close to the upper limits of their thermal tolerance and even small increases in summer water temperatures can lead to bleaching and...
Reef-building corals typically live close to the upper limits of their thermal tolerance and even small increases in summer water temperatures can lead to bleaching and mortality. Projections of coral reef futures based on forecasts of ocean temperatures indicate that by the end of this century, corals will experience their current thermal thresholds annually, which would lead to the widespread devastation of coral reef ecosystems. Here, we use skeletal cores of long-lived Porites corals collected from 14 reefs across the northern Great Barrier Reef, the Coral Sea, and New Caledonia to evaluate changes in their sensitivity to heat stress since 1815. High-density 'stress bands'-indicative of past bleaching-first appear during a strong pre-industrial El Niño event in 1877 but become significantly more frequent in the late twentieth and early twenty-first centuries in accordance with rising temperatures from anthropogenic global warming. However, the proportion of cores with stress bands declines following successive bleaching events in the twenty-first century despite increasing exposure to heat stress. Our findings demonstrate an increase in the thermal tolerance of reef-building corals and offer a glimmer of hope that at least some coral species can acclimatize fast enough to keep pace with global warming.
Topics: Acclimatization; Animals; Anthozoa; Coral Reefs; Hot Temperature; New Caledonia; Queensland; Seawater
PubMed: 30836872
DOI: 10.1098/rspb.2019.0235 -
Experimental Physiology Jul 2024
Topics: Altitude; Humans; Acclimatization; Hypoxia; Pulmonary Ventilation
PubMed: 38638075
DOI: 10.1113/EP091920 -
BMC Genomics Dec 2022Seagrasses are higher marine flowering plants that evolved from terrestrial plants, but returned to the sea during the early evolution of monocotyledons through several...
BACKGROUND
Seagrasses are higher marine flowering plants that evolved from terrestrial plants, but returned to the sea during the early evolution of monocotyledons through several separate lineages. Thus, they become a good model for studying the adaptation of plants to the marine environment. Sequencing of the mitochondrial (mt) genome of seagrasses is essential for understanding their evolutionary characteristics.
RESULTS
In this study, we sequenced the mt genome of two endangered seagrasses (Zostera japonica and Phyllospadix iwatensis). These data and data on previously sequenced mt genomes from monocotyledons provide new evolutionary evidence of genome size reduction, gene loss, and adaptive evolution in seagrasses. The mt genomes of Z. japonica and P. iwatensis are circular. The sizes of the three seagrasses (including Zostera marine) that have been sequenced to date are smaller than that of other monocotyledons. Additionally, we found a large number of repeat sequences in seagrasses. The most abundant long repeat sequences were 31-40 bp repeats. Our study also found that seagrass species lost extensive ribosomal protein genes during evolution. The rps7 gene and the rpl16 gene of P. iwatensis are exceptions to this trend. The phylogenetic analysis based on the mt genome strongly supports the previous results. Furthermore, we identified five positive selection genes (atp8, nad3, nad6, ccmFn, and matR) in seagrasses that may be associated with their adaptation to the marine environment.
CONCLUSIONS
In this study, we sequenced and annotated the mt genomes of Z. japonica and P. iwatensis and compared them with the genome of other monocotyledons. The results of this study will enhance our understanding of seagrass adaptation to the marine environment and can inform further investigations of the seagrass mt genome.
Topics: Genome, Mitochondrial; Phylogeny; Acclimatization; Genome Size; Magnoliopsida
PubMed: 36463111
DOI: 10.1186/s12864-022-09046-x -
Experimental Physiology Mar 2024Planet Earth is warming at an unprecedented rate and our future is now assured to be shaped by the consequences of more frequent hot days and extreme heat. Humans will... (Review)
Review
Planet Earth is warming at an unprecedented rate and our future is now assured to be shaped by the consequences of more frequent hot days and extreme heat. Humans will need to adapt both behaviorally and physiologically to thrive in a hotter climate. From a physiological perspective, countless studies have shown that human heat acclimation increases thermoeffector output (i.e., sweating and skin blood flow) and lowers cardiovascular strain (i.e., heart rate) during heat stress. However, the mechanisms mediating these adaptations remain understudied. Furthermore, several possible benefits of heat acclimation for other systems and functions involved in maintaining health and performance during heat stress remain to be elucidated. This review summarizes recent advances in human heat acclimation, with emphasis on recent studies that (1) advanced our understanding of the mechanisms mediating improved thermoeffector output and (2) investigated adaptations that go beyond those classically associated with heat acclimation. We highlight that these studies have contributed to a better understanding of the integrated physiological responses underlying human heat acclimation while leaving key unanswered questions that will need to be addressed in the future.
Topics: Humans; Body Temperature Regulation; Acclimatization; Hot Temperature; Adaptation, Physiological; Sweating
PubMed: 37885125
DOI: 10.1113/EP091207 -
Proceedings. Biological Sciences Aug 2022Coral reefs are facing unprecedented mass bleaching and mortality events due to marine heatwaves and climate change. To avoid extirpation, corals must adapt. Individual...
Coral reefs are facing unprecedented mass bleaching and mortality events due to marine heatwaves and climate change. To avoid extirpation, corals must adapt. Individual variation in heat tolerance and its heritability underpin the potential for coral adaptation. However, the magnitude of heat tolerance variability within coral populations is largely unresolved. We address this knowledge gap by exposing corals from a single reef to an experimental marine heatwave. We found that double the heat stress dosage was required to induce bleaching in the most-tolerant 10%, compared to the least-tolerant 10% of the population. By the end of the heat stress exposure, all of the least-tolerant corals were dead, whereas the most-tolerant remained alive. To contextualize the scale of this result over the coming century, we show that under an ambitious future emissions scenario, such differences in coral heat tolerance thresholds equate to up to 17 years delay until the onset of annual bleaching and mortality conditions. However, this delay is limited to only 10 years under a high emissions scenario. Our results show substantial variability in coral heat tolerance which suggests scope for natural or assisted evolution to limit the impacts of climate change in the short-term. For coral reefs to persist through the coming century, coral adaptation must keep pace with ocean warming, and ambitious emissions reductions must be realized.
Topics: Acclimatization; Animals; Anthozoa; Climate Change; Coral Reefs; Thermotolerance
PubMed: 36043280
DOI: 10.1098/rspb.2022.0872 -
Proceedings of the National Academy of... Aug 2023In the billion-dollar global illegal wildlife trade, rosewoods have been the world's most trafficked wild product since 2005. and are the most sought-after rosewoods...
In the billion-dollar global illegal wildlife trade, rosewoods have been the world's most trafficked wild product since 2005. and are the most sought-after rosewoods in the Greater Mekong Subregion. They are exposed to significant genetic risks and the lack of knowledge on their adaptability limits the effectiveness of conservation efforts. Here, we present genome assemblies and range-wide genomic scans of adaptive variation, together with predictions of genomic offset to climate change. Adaptive genomic variation was differentially associated with temperature and precipitation-related variables between the species, although their natural ranges overlap. The findings are consistent with differences in pioneering ability and in drought tolerance. We predict their genomic offsets will increase over time and with increasing carbon emission pathway but at a faster pace in than in . These results and the distinct gene-environment association in the eastern coastal edge of Vietnam suggest species-specific conservation actions: germplasm representation across the range in and focused on hotspots of genomic offset in . We translated our genomic models into a seed source matching application, , to rapidly inform restoration efforts. Our ecological genomic research uncovering contrasting selection forces acting in sympatric rosewoods is of relevance to conserving tropical trees globally and combating risks from climate change.
Topics: Adaptation, Physiological; Acclimatization; Genomics; Climate Change
PubMed: 37549265
DOI: 10.1073/pnas.2301603120 -
Scientific Reports Dec 2021Efficient protocols for callus induction and micro propagation of Saussurea costus (Falc.) Lipsch were developed and phytochemical diversity of wild and in-vitro...
Efficient protocols for callus induction and micro propagation of Saussurea costus (Falc.) Lipsch were developed and phytochemical diversity of wild and in-vitro propagated material was investigated. Brown and red compact callus was formed with frequency of 80-95%, 78-90%, 70-95% and 65-80% from seeds, leaf, petiole and root explants, respectively. MS media supplemented with BAP (2.0 mgL), NAA (1.0 mgL) and GA3 (0.25 mgL) best suited for multiple shoot buds initiation (82%), while maximum shoot length was formed on media with BAP (1.5 mgL), NAA (0.25 mgL) and Kinetin (0.5 mgL). Full strength media with IAA (0.5 mgL) along with IBA (0.5 mgL) resulted in early roots initiation. Similarly, maximum rooting (87.57%) and lateral roots formation (up to 6.76) was recorded on full strength media supplemented with BAP (0.5 mgL), IAA (0.5 mgL) and IBA (0.5 mgL). Survival rate of acclimatized plantlets in autoclaved garden soil, farmyard soil, and sand (2:1:1) was 87%. Phytochemical analysis revealed variations in biochemical contents i.e. maximum sugar (808.32 µM/ml), proline (48.14 mg/g), ascorbic acid (373.801 mM/g) and phenolic compounds (642.72 mgL) were recorded from callus cultured on different stress media. Nonetheless, highest flavenoids (59.892 mg/g) and anthocyanin contents (32.39 mg/kg) were observed in in-vitro propagated plants. GC-MS analysis of the callus ethyl acetate extracts revealed 24 different phytochemicals. The variability in secondary metabolites of both wild and propagated plants/callus is reported for the first time for this species. This study may provide a baseline for the conservation and sustainable utilization of S. costus with implications for isolation of unique and pharmacologically active compounds from callus or regenerated plantlets.
Topics: Acclimatization; Kinetin; Phytochemicals; Plant Leaves; Plant Roots; Plant Shoots; Plants, Medicinal; Regeneration; Saussurea
PubMed: 34880342
DOI: 10.1038/s41598-021-03032-1 -
PloS One 2020Climate change is impacting coral reefs now. Recent pan-tropical bleaching events driven by unprecedented global heat waves have shifted the playing field for coral reef...
Climate change is impacting coral reefs now. Recent pan-tropical bleaching events driven by unprecedented global heat waves have shifted the playing field for coral reef management and policy. While best-practice conventional management remains essential, it may no longer be enough to sustain coral reefs under continued climate change. Nor will climate change mitigation be sufficient on its own. Committed warming and projected reef decline means solutions must involve a portfolio of mitigation, best-practice conventional management and coordinated restoration and adaptation measures involving new and perhaps radical interventions, including local and regional cooling and shading, assisted coral evolution, assisted gene flow, and measures to support and enhance coral recruitment. We propose that proactive research and development to expand the reef management toolbox fast but safely, combined with expedient trialling of promising interventions is now urgently needed, whatever emissions trajectory the world follows. We discuss the challenges and opportunities of embracing new interventions in a race against time, including their risks and uncertainties. Ultimately, solutions to the climate challenge for coral reefs will require consideration of what society wants, what can be achieved technically and economically, and what opportunities we have for action in a rapidly closing window. Finding solutions that work for coral reefs and people will require exceptional levels of coordination of science, management and policy, and open engagement with society. It will also require compromise, because reefs will change under climate change despite our best interventions. We argue that being clear about society's priorities, and understanding both the opportunities and risks that come with an expanded toolset, can help us make the most of a challenging situation. We offer a conceptual model to help reef managers frame decision problems and objectives, and to guide effective strategy choices in the face of complexity and uncertainty.
Topics: Acclimatization; Animals; Anthozoa; Climate Change; Conservation of Natural Resources; Coral Reefs; Ecosystem; Models, Theoretical
PubMed: 32845878
DOI: 10.1371/journal.pone.0236399 -
Experimental Physiology Jan 2023What is the central question of this study? How does hypoxic pulmonary vasoconstriction and the response to supplemental oxygen change over time at high altitude? What...
NEW FINDINGS
What is the central question of this study? How does hypoxic pulmonary vasoconstriction and the response to supplemental oxygen change over time at high altitude? What is the main finding and its importance? Lowlanders and partially de-acclimatized Sherpa both demonstrated pulmonary vascular responsiveness to supplemental oxygen that was maintained for 12 days' exposure to progressively increasing altitude. An additional 2 weeks' acclimatization at 5050 m altitude rendered the pulmonary vasculature minimally responsive to oxygen similar to the fully acclimatized non-ascent Sherpa. Additional hypoxic exposure at that time point did not augment hypoxic pulmonary vasoconstriction.
ABSTRACT
Prolonged alveolar hypoxia leads to pulmonary vascular remodelling. We examined the time course at altitude, over which hypoxic pulmonary vasoconstriction goes from being acutely reversible to potentially irreversible. Study subjects were lowlanders (n = 20) and two Sherpa groups. All Sherpa were born and raised at altitude. One group (ascent Sherpa, n = 11) left altitude and after de-acclimatization in Kathmandu for ∼7 days re-ascended with the lowlanders over 8-10 days to 5050 m. The second Sherpa group (non-ascent Sherpa, n = 12) remained continuously at altitude. Pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) were measured while breathing ambient air and following supplemental oxygen. During ascent PASP and PVR increased in lowlanders and ascent Sherpa; however, with supplemental oxygen, lowlanders had significantly greater decrease in PASP (P = 0.02) and PVR (P = 0.02). After ∼14 days at 5050 m, PASP decreased with supplemental oxygen (mean decrease: 3.9 mmHg, 95% CI 2.1-5.7 mmHg, P < 0.001); however, PVR was unchanged (P = 0.49). In conclusion, PASP and PVR increased with gradual ascent to altitude and decreased via oxygen supplementation in both lowlanders and ascent Sherpa. Following ∼14 days at 5050 m altitude, there was no change in PVR to hypoxia or O supplementation in lowlanders or either Sherpa group. These data show that both duration of exposure and residential altitude influence the pulmonary vascular responses to hypoxia.
Topics: Humans; Altitude; Hypoxia; Altitude Sickness; Acclimatization; Oxygen
PubMed: 36404588
DOI: 10.1113/EP090458 -
PloS One 2013High altitude acclimatization is a series of physiological responses taking places when subjects go to altitude. Many factors could influence these processes, such as...
High altitude acclimatization is a series of physiological responses taking places when subjects go to altitude. Many factors could influence these processes, such as altitude, ascending speed and individual characteristics. In this study, based on a repeated measurement design of three sequential measurements at baseline, acute phase and chronic phase, we evaluated the effect of BMI, smoking and drinking on a number of physiological responses in high altitude acclimatization by using mixed model and partial least square path model on a sample of 755 Han Chinese young males. We found that subjects with higher BMI responses were reluctant to hypoxia. The effect of smoking was not significant at acute phase. But at chronic phase, red blood cell volume increased less while respiratory function increased more for smoking subjects compared with nonsmokers. For drinking subjects, red blood cell volume increased less than nondrinkers at both acute and chronic phases, while blood pressures increased more than nondrinkers at acute phase and respiratory function, red blood cell volume and oxygen saturation increased more than nondrinkers at chronic phase. The heavy and long-term effect of smoking, drinking and other factors in high altitude acclimatization needed to be further studied.
Topics: Acclimatization; Adolescent; Altitude; Asian People; Body Mass Index; Drinking; Humans; Male; Smoking; Young Adult
PubMed: 24260204
DOI: 10.1371/journal.pone.0079346