ORCID Profile
0000-0001-8781-5736
Current Organisation
The University of Hong Kong
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Phycology (incl. Marine Grasses) | Plant Biology | Plant Physiology | Global Change Biology
Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Expanding Knowledge in the Biological Sciences |
Publisher: Elsevier BV
Date: 03-2019
Publisher: Wiley
Date: 30-12-2014
Publisher: Wiley
Date: 10-05-2016
DOI: 10.1002/ECE3.2097
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JTHERBIO.2017.02.011
Abstract: Intertidal organisms have evolved physiological mechanisms that enable them to maintain performance and survive during periods of severe environmental stress with temperatures close to their tolerance limits. The level of these adaptive responses in thermal physiology can vary among populations of broadly distributed species depending on their particular environmental context and genetic backgrounds. Here we examined thermal performances and reaction norms for metabolic rate (MR) and heart rate (HR) of seven populations of the porcelanid crab Petrolisthes violaceus from markedly different thermal environments across the latitudinal gradient of ~3000km. Physiological responses of this intertidal crab under common-garden conditions suggest the absence of local thermal adaptation along the geographic gradient (i.e., lack of latitudinal compensation). Moreover, thermal physiological sensitivities and performances in response to increased temperatures evidenced the existence of some level of: i) metabolic rate control or depression during warm temperature exposures and ii) homeostasis/canalization (i.e., absence or low levels of plasticity) in physiological traits that may reflect some sort of buffering mechanism in most of the populations. Nevertheless, our results indicate that elevated temperatures can reduce cardiac function but not metabolic rate in high latitude crabs. The lack of congruence between HR and MR supports the idea that energy metabolism in marine invertebrates cannot be inferred from HR and different conclusions regarding geographic differentiation in energy metabolism can be obtained from both physiological traits. Integrating thermal physiology and species range extent can contribute to a better understanding of the likely effects of climate change on natural populations of marine ectotherms.
Publisher: Wiley
Date: 09-2019
DOI: 10.1111/EVO.13823
Abstract: Sequential polyandry may evolve as an insurance mechanism to reduce the risk of females choosing mates who are genetically inferior (intrinsic male quality hypothesis) or genetically incompatible (genetic incompatibility hypothesis). The prevalence of such indirect benefits remains controversial, however, because studies estimating the contributions of additive and nonadditive sources of genetic variation to offspring fitness have been limited to a small number of taxonomic groups. Here, we used artificial fertilization techniques combined with a crossclassified breeding design (North Carolina Type II) to simultaneously test the "good genes hypothesis" and the "genetic incompatibility hypothesis" in the brown toadlet (Pseudophryne bibronii) a terrestrial-breeding species with extreme sequential polyandry. Our results revealed no significant additive or nonadditive genetic effects on fertilization success. Moreover, they revealed no significant additive genetic effects, but highly significant nonadditive genetic effects (sire by dam interaction effects), on hatching success and larval survival to initial and complete metamorphosis. Taken together, these results indicate that offspring viability is significantly influenced by the combination of parental genotypes, and that negative interactions between parental genetic elements manifest during embryonic and larval development. More broadly, our findings provide quantitative genetic evidence that insurance against genetic incompatibility favors the evolution and maintenance of sequential polyandry.
Publisher: The Royal Society
Date: 28-01-2019
Abstract: How populations and species respond to modified environmental conditions is critical to their persistence both now and into the future, particularly given the increasing pace of environmental change. The process of adaptation to novel environmental conditions can occur via two mechanisms: (1) the expression of phenotypic plasticity (the ability of one genotype to express varying phenotypes when exposed to different environmental conditions), and (2) evolution via selection for particular phenotypes, resulting in the modification of genetic variation in the population. Plasticity, because it acts at the level of the in idual, is often hailed as a rapid-response mechanism that will enable organisms to adapt and survive in our rapidly changing world. But plasticity can also retard adaptation by shifting the distribution of phenotypes in the population, shielding it from natural selection. In addition to which, not all plastic responses are adaptive—now well-documented in cases of ecological traps. In this theme issue, we aim to present a considered view of plasticity and the role it could play in facilitating or hindering adaption to environmental change. This introduction provides a re-examination of our current understanding of the role of phenotypic plasticity in adaptation and sets the theme issue's contributions in their broader context. Four key themes emerge: the need to measure plasticity across both space and time the importance of the past in predicting the future the importance of the link between plasticity and sexual selection and the need to understand more about the nature of selection on plasticity itself. We conclude by advocating the need for cross-disciplinary collaborations to settle the question of whether plasticity will promote or retard species' rates of adaptation to ever-more stressful environmental conditions. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.
Publisher: The Company of Biologists
Date: 2014
DOI: 10.1242/JEB.101261
Abstract: Lower temperatures, extreme seasonality and shorter growing seasons at higher latitudes are expected to cause a decline in metabolic rates and annual growth rates of ectotherms. If a reduction in the rates of these biological processes involves a reduction in fitness, then organisms may evolve compensatory responses for the constraints imposed by high-latitude habitats. To test the existence of a latitudinal compensation in ectotherms we used a common garden experiment to investigate the extent to which the level of energy turnover (measured as standard metabolic rate, SMR) and the energy budget (energy allocation to growth) are affected by climatic constraints in three populations of the land snail Cornu aspersum, distributed across a latitudinal gradient of 1300 kms in Chile. Our results did not support the existence of a latitudinal compensation in metabolic rates (Metabolic Cold adaptation). However, there was a countergradient variation (CnGV) for growth rate in which the highest latitudinal population exhibited greater growth rates than their counterparts from lower latitudes. Surprisingly, this CnGV pattern was accompanied by a lower apparent dry-matter digestibility, which could highlight a differential assimilation of ingested nutrients into somatic tissue, revealing enhanced growth efficiency in snails from the highest latitudinal habitat. Our evidence highlights that adjustments in energy allocation to the digestive machinery and to protein storage could act as a latitudinal compensation for enhanced growth efficiency in snails from the highest latitudinal population.
Publisher: Elsevier BV
Date: 05-2023
Publisher: The Company of Biologists
Date: 2014
DOI: 10.1242/JEB.108217
Abstract: Environmental temperature has profound implications on the biological performance and biogeographical distribution of ectothermic species. Variation of this abiotic factor across geographic gradients is expected to produces physiological differentiation and local adaptation of natural populations depending on their thermal tolerances and physiological sensitivities. Here, we have studied geographic variation in whole-organism thermal physiology of seven populations of the porcelain crab Petrolisthes violaceus across a latitudinal gradient of 3000 km, characterized by a cline of thermal conditions. Our study found that populations of P. violaceus exhibit a lack of differences in the limits of their thermal performance curves and a negative correlation of their optimal temperatures with latitude. Additionally, our findings showed that high latitude populations of P. violaceus exhibited broader thermal tolerances, which is consistent with the Climatic Variability Hypothesis. Interestingly, under a future scenario of warming oceans, the thermal safety margins of P. violaceus indicate that lower latitude populations can physiologically tolerate the ocean warming scenarios projected by the IPCC for the end of the twenty-first century.
Publisher: Frontiers Media SA
Date: 16-06-2022
DOI: 10.3389/FMARS.2022.864797
Abstract: Environmental variability is an intrinsic characteristic of nature. Variability in factors such as temperature, UV, salinity, and nutrient availability can influence structural and functional properties of marine microbial organisms. This influence has profound implications for biochemical cycles and the ecosystem services provided by the oceans. In this review we discuss some of the most relevant mechanisms underpinning adaptive strategies of microbial organisms in variable and dynamic oceans. We assess the extent to which the magnitude and rate of environmental change influence plastic phenotypic adjustments and evolutionary trajectories of microbial populations. This understanding is fundamental for developing better predictions regarding microbial dynamics at ecological and evolutionary time-scales and in response to climate change.
Publisher: Wiley
Date: 05-12-2023
DOI: 10.1111/ELE.14150
Abstract: Assessing the heat tolerance (CTmax) of organisms is central to understand the impact of climate change on bio ersity. While both environment and evolutionary history affect CTmax, it remains unclear how these factors and their interplay influence ecological interactions, communities and ecosystems under climate change. We collected and reared caterpillars and parasitoids from canopy and ground layers in different seasons in a tropical rainforest. We tested the CTmax and Thermal Safety Margins (TSM) of these food webs with implications for how species interactions could shift under climate change. We identified strong influence of phylogeny in herbivore–parasitoid community heat tolerance. The TSM of all insects were narrower in the canopy and parasitoids had lower heat tolerance compared to their hosts. Our CTmax‐based simulation showed higher herbivore–parasitoid food web instability under climate change than previously assumed, highlighting the vulnerability of parasitoids and related herbivore control in tropical rainforests, particularly in the forest canopy.
Publisher: Springer Science and Business Media LLC
Date: 02-11-2016
DOI: 10.1038/SREP36516
Abstract: The edible sea urchin Loxechinus albus (Molina, 1782) is a keystone species in the littoral benthic systems of the Pacific coast of South America. The international demand for high-quality gonads of this echinoderm has led to an extensive exploitation and decline of its natural populations. Consequently, a more thorough understanding of L. albus gonad development and gametogenesis could provide valuable resources for aquaculture applications, management, conservation and studies about the evolution of functional and structural pathways that underlie the reproductive toolkit of marine invertebrates. Using a high-throughput sequencing technology, we explored the male gonad transcriptome of this highly fecund sea urchin. Through a de novo assembly approach we obtained 42,530 transcripts of which 15,544 (36.6%) had significant alignments to known proteins in public databases. From these transcripts, approximately 73% were functionally annotated allowing the identification of several candidate genes that are likely to play a central role in developmental processes, nutrient reservoir activity, sexual reproduction, gamete generation, meiosis, sex differentiation, sperm motility, male courtship behavior and fertilization. Additionally, comparisons with the male gonad transcriptomes of other echinoderms revealed several conserved orthologous genes, suggesting that similar functional and structural pathways underlie the reproductive development in this group and other marine invertebrates.
Publisher: Wiley
Date: 10-10-2023
DOI: 10.1002/LOM3.10574
Publisher: Wiley
Date: 10-11-2014
DOI: 10.1002/ECE3.1315
Publisher: Wiley
Date: 15-04-2018
DOI: 10.1002/ECE3.3979
Publisher: Copernicus GmbH
Date: 25-01-2023
Abstract: Abstract. Approximately one-quarter of the CO2 emitted to the atmosphere annually from human activities is absorbed by the ocean, resulting in a reduction of seawater pH and shifts in seawater carbonate chemistry. This multi-decadal process, termed “anthropogenic ocean acidification” (OA), has been shown to have detrimental impacts on marine ecosystems. Recent years have seen a globally coordinated effort to measure the changes in seawater chemistry caused by OA, with best practices now available for these measurements. In contrast to these substantial advances in observing physicochemical changes due to OA, quantifying their biological consequences remains challenging, especially from in situ observations under real-world conditions. Results from 2 decades of controlled laboratory experiments on OA have given insight into the likely processes and mechanisms by which elevated CO2 levels affect biological process, but the manifestation of these process across a plethora of natural situations has yet to be fully explored. This challenge requires us to identify a set of fundamental biological and ecological indicators that are (i) relevant across all marine ecosystems, (ii) have a strongly demonstrated link to OA, and (iii) have implications for ocean health and the provision of ecosystem services with impacts on local marine management strategies and economies. This paper draws on the understanding of biological impacts provided by the wealth of previous experiments, as well as the findings of recent meta-analyses, to propose five broad classes of biological indicators that, when coupled with environmental observations including carbonate chemistry, would allow the rate and severity of biological change in response to OA to be observed and compared. These broad indicators are applicable to different ecological systems, and the methods for data analysis suggested here would allow researchers to combine biological response data across regional and global scales by correlating rates of biological change with the rate of change in carbonate chemistry parameters. Moreover, a method using laboratory observation to design an optimal observing strategy (frequency and duration) and observe meaningful biological rates of change highlights the factors that need to be considered when applying our proposed observation strategy. This innovative observing methodology allows inclusion of a wide ersity of marine ecosystems in regional and global assessments and has the potential to increase the contribution of OA observations from countries with developing OA science capacity.
Publisher: Springer Science and Business Media LLC
Date: 02-2022
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/MF18355
Abstract: Factualised storytelling narratives may assist scientists to communicate inter-disciplinary, multi-scale climate change research with stakeholders and non-expert members of the community. Scientists are increasingly required to balance scientific rigour with storytelling narratives that can facilitate climate change mitigation and adaptation as new communication technologies evolve. In this editorial to the research front, ‘Climate impacts on marine system structure and function: molecules to ecosystems’, a review of climate change coverage in the media since 1980 showed that climate change science had a substantial voice globally and, in particular, in countries with carbon-dependent economies. However, the effective communication of multi-scale climate change research in the media can be complicated by the complex messages, the lack of training scientists receive in communication, and the traditionally distant relationship that the scientific community has with the media and, more so, with the broader community. Considerable scientific effort is being made to overcome these challenges as additional responsibility is placed on the scientific community to produce newsworthy scientific outputs. However, the integration of inter-disciplinary, multi-scale information, such as outlined in this research front, can result in more holistic climate change stories that scientists can effectively communicate with stakeholders and the broader community.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.GENE.2015.06.059
Abstract: The superfamily Curculionoidea is one of the most erse groups of insects in the world, including many species which are crop pests. Within this group, the native raspberry weevil, Aegorhinus superciliosus (Guérin, 1830), is an important pest in blueberry and raspberry fields in southern South America. Using a 454 sequencing approach, we sequenced and annotated the mitogenome of A. superciliosus, it, providing the first such information for any species in the tribe Aterpini, subfamily Cyclominae. The assembled mitogenome is a circular DNA molecule 15,121bp in length containing all 37 genes normally found in metazoans. Mitogenome organization and transcriptional orientation in A. superciliosus showed the same pattern that characterizes the suborder Polyphaga. Bayesian and Maximum Likelihood phylogenetic analyses supported the monophyly of the tribe Aterpini and the subfamily Cyclominae, recovering this clade in a sister group relationship with Entiminae and Hyperinae. The monophyly of these three subfamilies defines a critical transition to an ectophagous lifestyle in the larvae, from an ancestrally endophagous larval lifestyle in all other lineages. The sequenced mitogenome of A. superciliosus can provide basic data for future studies investigating population history, molecular systematics, stress ecophysiology and phylogeography.
Publisher: Copernicus GmbH
Date: 26-09-2022
DOI: 10.5194/EGUSPHERE-2022-907
Abstract: Abstract. Approximately one quarter of the CO2 emitted to the atmosphere annually from human activities is absorbed by the ocean, resulting in a reduction of seawater pH and shifts in seawater carbonate chemistry. This multi-decadal process, termed “anthropogenic ocean acidification” (OA) has been shown to have detrimental impacts on marine ecosystems. Recent years have seen a globally coordinated effort to measure the changes in seawater chemistry caused by OA, with best practices now available for these measurements. In contrast to these substantial advances in observing physico-chemical changes due to OA, quantifying their biological consequences remains challenging, especially from in-situ observations under real-world conditions. Results from two decades of controlled laboratory experiments on OA have given insight into the likely processes and mechanisms by which elevated CO2 levels affect biological process, but the manifestation of these process across a plethora of natural situations has yet to be explored fully. This challenge requires us to identify a set of fundamental biological and ecological indicators that are i) relevant across all marine ecosystems, ii) have a strongly demonstrated link to OA, and iii) have implications for ocean health and the provision of ecosystem services with impacts on local marine management strategies and economies. This paper draws on the understanding of biological impacts provided by the wealth of previous experiments, as well as the findings of recent meta-analyses, to propose five broad classes of biological indicators that, when coupled with environmental observations, including carbonate chemistry, would allow the rate and severity of biological change in response to OA to be observed and compared. These broad indicators are applicable to different ecological systems, and the methods for data analysis suggested here would allow researchers to combine biological response data across regional and global scales by correlating rates of biological change with the rate of change in carbonate chemistry parameters. Moreover, a method using laboratory observation to design an optimal observing strategy (frequency and duration) and observe meaningful biological rates of change highlights the factors that need to be considered when applying our proposed observation strategy. This innovative observing methodology allows inclusion of a wide ersity of marine ecosystems in regional and global assessments and has the potential to increase the contribution of OA observations from countries with developing OA science capacity.
Publisher: Elsevier BV
Date: 05-2022
Publisher: Wiley
Date: 13-01-2021
DOI: 10.1111/EVO.14160
Publisher: Copernicus GmbH
Date: 14-03-2018
Abstract: Abstract. Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally over-calcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hyper-calcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 vs. 1200 µatm), the over-calcified morphotypes showed the same growth inhibition (−29.1±6.3 %) as moderately calcified morphotypes isolated from non-acidified water (−30.7±8.8 %). Under the high-CO2–low-pH condition, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC ∕ POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. The high-CO2–low-pH condition affected coccolith morphology equally or more strongly in over-calcified strains compared to moderately calcified strains. High-CO2–low-pH conditions appear not to directly select for exceptionally over-calcified morphotypes over other morphotypes, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turnover and large population sizes, do not necessarily exhibit adaptations to naturally high-CO2 upwellings, and this ubiquitous coccolithophore may be near the limit of its capacity to adapt to ongoing ocean acidification.
Publisher: Wiley
Date: 28-09-2016
DOI: 10.1111/EVA.12411
Abstract: To project how ocean acidification will impact biological communities in the future, it is critical to understand the potential for local adaptation and the physiological plasticity of marine organisms throughout their entire life cycle, as some stages may be more vulnerable than others. Coralline algae are ecosystem engineers that play significant functional roles in oceans worldwide and are considered vulnerable to ocean acidification. Using different stages of coralline algae, we tested the hypothesis that populations living in environments with higher environmental variability and exposed to higher levels of pCO 2 would be less affected by high pCO 2 than populations from a more stable environment experiencing lower levels of pCO 2 . Our results show that spores are less sensitive to elevated pCO 2 than adults. Spore growth and mortality were not affected by pCO 2 level however, elevated pCO 2 negatively impacted the physiology and growth rates of adults, with stronger effects in populations that experienced both lower levels of pCO 2 and lower variability in carbonate chemistry, suggesting local adaptation. Differences in physiological plasticity and the potential for adaptation could have important implications for the ecological and evolutionary responses of coralline algae to future environmental changes.
Publisher: Springer Science and Business Media LLC
Date: 30-11-2015
DOI: 10.1007/S11033-014-3847-5
Abstract: The edible Chilean red sea urchin, Loxechinus albus, is the only species of its genus and endemic to the Southeastern Pacific. In this study, we reconstructed the mitochondrial genome of L. albus by combining Sanger and pyrosequencing technologies. The mtDNA genome had a length of 15,737 bp and encoded the same 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes as other animal mtDNAs. The size of this mitogenome was similar to those of other Echinodermata species. Structural comparisons showed a highly conserved structure, composition, and gene order within Echinoidea and Holothuroidea, and nearly identical gene organization to that found in Asteroidea and Crinoidea, with the majority of differences explained by the inversions of some tRNA genes. Phylogenetic reconstruction supported the monophyly of Echinozoa and recovered the monophyletic relationship of Holothuroidea and Echinoidea. Within Holothuroidea, Bayesian and maximum likelihood analyses recovered a sister-group relationship between Dendrochirotacea and Aspidochirotida. Similarly within Echinoidea, these analyses revealed that L. albus was closely related to Paracentrotus lividus, both being part of a sister group to Strongylocentrotidae and Echinometridae. In addition, two major clades were found within Strongylocentrotidae. One of these clades comprised all of the representative species Strongylocentrotus and Hemicentrotus, whereas the other included species of Mesocentrotus and Pseudocentrotus.
Publisher: Wiley
Date: 23-05-2023
DOI: 10.1002/BIOF.1976
Abstract: The marsupial Monito del monte ( Dromiciops gliroides ) utilizes both daily and seasonal bouts of torpor to preserve energy and prolong survival during periods of cold and unpredictable food availability. Torpor involves changes in cellular metabolism, including specific changes to gene expression that is coordinated in part, by the posttranscriptional gene silencing activity of microRNAs (miRNA). Previously, differential miRNA expression has been identified in D . gliroides liver and skeletal muscle however, miRNAs in the heart of Monito del monte remained unstudied. In this study, the expression of 82 miRNAs was assessed in the hearts of active and torpid D . gliroides , finding that 14 were significantly differentially expressed during torpor. These 14 miRNAs were then used in bioinformatic analyses to identify Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were predicted to be most affected by these differentially expressed miRNAs. Overexpressed miRNAs were predicted to primarily regulate glycosaminoglycan biosynthesis, along with various signaling pathways such as Phosphoinositide‐3‐kinase rotein kinase B and transforming growth factor‐β. Similarly, signaling pathways including phosphatidylinositol and Hippo were predicted to be regulated by the underexpression of miRNAs during torpor. Together, these results suggest potential molecular adaptations that protect against irreversible tissue damage and enable continued cardiac and vascular function despite hypothermia and limited organ perfusion during torpor.
Publisher: Elsevier BV
Date: 12-2023
Publisher: Copernicus GmbH
Date: 06-09-2017
Publisher: Wiley
Date: 13-10-2020
DOI: 10.1111/GCB.15359
Abstract: Impacts of climate change are apparent in natural systems around the world. Many species are and will continue to struggle to persist in their current location as their preferred environment changes. Traditional conservation efforts aiming to prevent local extinctions have focused on two aspects that theoretically enhance genetic ersity—population connectivity and population size—through ‘passive interventions’ (such as protected areas and connectivity corridors). However, the exceptionally rapid loss of bio ersity that we are experiencing as result of anthropogenic climate change has shifted conservation approaches to more ‘active interventions’ (such as rewilding, assisted gene flow, assisted evolution, artificial selection, genetic engineering). We integrate genetic/genomic approaches into an evolutionary biology framework in order to discuss with scientists, conservation managers and decision makers about the opportunities and risks of interventions that need careful consideration in order to avoid unwanted evolutionary outcomes.
Publisher: Springer Science and Business Media LLC
Date: 30-05-2022
DOI: 10.1038/S41467-022-30690-0
Abstract: Animals display a fascinating ersity of body plans. Correspondingly, genomic analyses have revealed dynamic evolution of gene gains and losses among animal lineages. Here we sequence six new myriapod genomes (three millipedes, three centipedes) at key phylogenetic positions within this major but understudied arthropod lineage. We combine these with existing genomic resources to conduct a comparative analysis across all available myriapod genomes. We find that millipedes generally have considerably smaller genomes than centipedes, with the repeatome being a major contributor to genome size, driven by independent large gains of transposons in three centipede species. In contrast to millipedes, centipedes gained a large number of gene families after the subphyla erged, with gains contributing to sensory and locomotory adaptations that facilitated their ecological shift to predation. We identify distinct horizontal gene transfer (HGT) events from bacteria to millipedes and centipedes, with no identifiable HGTs shared among all myriapods. Loss of juvenile hormone O-methyltransferase , a key enzyme in catalysing sesquiterpenoid hormone production in arthropods, was also revealed in all millipede lineages. Our findings suggest that the rapid evolution of distinct genomic pathways in centipede and millipede lineages following their ergence from the myriapod ancestor, was shaped by differing ecological pressures.
Publisher: Copernicus GmbH
Date: 06-09-2017
DOI: 10.5194/BG-2017-303
Abstract: Abstract. Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the Eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally overcalcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hypercalcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 µatm vs. 1200 µatm), the overcalcified morphotypes showed the same growth inhibition (−29.1 ± 6.3 %) as moderately calcified morphotypes isolated from non-acidified water (−30.7 ± 8.8 %). Under OA conditions, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC/POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. OA affected coccolith morphology equally or more strongly in overcalcified strains compared to moderately calcified strains. OA conditions appear not to directly select for exceptionally overcalcified morphotypes over other morphotypes directly, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turn-over and large population sizes, do not necessarily exhibit adaptations to naturally high CO2 upwellings, and this ubiquitous coccolithophore may be near a limit of its capacity to adapt to ongoing ocean acidification.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-02-2019
Publisher: Oxford University Press (OUP)
Date: 25-06-2013
Publisher: Oxford University Press (OUP)
Date: 17-04-2016
DOI: 10.1111/ZOJ.12417
Publisher: Springer Science and Business Media LLC
Date: 06-02-2021
Publisher: Wiley
Date: 17-01-2012
Publisher: Cold Spring Harbor Laboratory
Date: 08-02-2023
DOI: 10.1101/2023.02.08.527599
Abstract: Extreme thermal conditions on rocky shores are challenging to the survival of intertidal ectotherms, especially during emersion periods. Yet, many species are highly successful in these environments in part due to their ability to regulate intrinsic mechanisms associated with physiological stress and their metabolic demands. More recently, there has been a growing awareness that other extrinsic mechanisms, such as animal-associated microbial communities, can also influence the tolerance and survival of ectotherms under stressful conditions. The extent to which intrinsic and extrinsic mechanisms are functionally linked as part of the overall adaptive response of intertidal animals to temperature change and stress is, however, poorly understood. Here, we examined the dynamics and potential interactions of intrinsic and extrinsic mechanisms in the ecology of the tropical high shore rock oyster, Isognomon nucleus . We found that oysters modulate their internal biochemistry (PUFA-oxidised metabolites including 5-F 2t -IsoP, 10-F 4t -NeuroP, 13-F 4t -NeuroP, and 16-F 1t -PhytoP) as part of their adaptive regulation to cope with physiological stress during periods of extreme temperatures when emersed. While we detected extrinsic microbiome changes in alpha ersity, the overall taxonomic and functional structure of the microbiome showed temporal stability with no association with the host biochemical profiles. Our finding here suggests that the microbiome taxonomic and functional structure is maintained by a stable host control (not associated to the host biochemistry) and/or that the microbiome (independent of the host) is resilient to the temperature fluctuations and extremes. This microbiome stability is likely to contribute to the oyster, I. nucleus thermal tolerance, in addition to the intrinsic biochemical adjustment, to survive in the thermally challenging intertidal environment.
Publisher: Wiley
Date: 18-07-2023
DOI: 10.1002/PAN3.10495
Abstract: Over recent decades, our understanding of climate change has accelerated greatly, but unfortunately, observable impacts have increased in tandem. Both mitigation and adaptation have not progressed at the level or scale warranted by our collective knowledge on climate change. More effective approaches to engage people on current and future anthropogenic climate change effects are urgently needed. Here, we show how species whose distributions are shifting in response to climate change, that is, ‘species‐on‐the‐move’, present an opportunity to engage people with climate change by linking to human values, and our deep connections with the places in which we live, in a locally relevant yet globally coherent narrative. Species‐on‐the‐move can impact ecosystem structure and function, food security, human health, livelihoods, culture and even the climate itself through feedback to the climate system, presenting a wide variety of potential pathways for people to understand that climate change affects them personally as in iduals. Citizen science focussed on documenting changes in bio ersity is one approach to foster a deeper engagement on climate change. However, other possible avenues, which may offer potential to engage people currently unconnected with nature, include arts, games or collaborations with rural agriculture (e.g. new occurrences of pest species) or fisheries organisations (e.g. shifting stocks) or healthcare providers (e.g. changing distributions of disease vectors). Through the importance we place on the aspects of life impacted by the redistribution of species around us, species‐on‐the‐move offer emotional pathways to connect with people on the complex issue of climate change in profound ways that have the potential to engender interest and action on climate change. Read the free Plain Language Summary for this article on the Journal blog.
Publisher: Wiley
Date: 21-03-2017
DOI: 10.1002/ECE3.2850
Publisher: Wiley
Date: 16-09-2015
Abstract: This is the first de novo transcriptome and complete mitochondrial genome of an Antarctic sea urchin species sequenced to date. Sterechinus neumayeri is an Antarctic sea urchin and a model species for ecology, development, physiology and global change biology. To identify transcripts important to ocean acidification (OA) and thermal stress, this transcriptome was created pooling, and 13 larval s les representing developmental stages on day 11 (late gastrula), 19 (early pluteus) and 30 (mid pluteus) maintained at three CO2 levels (421, 652, and 1071 μatm) as well as four additional heat-shocked s les. The normalized cDNA pool was sequenced using emulsion PCR (pyrosequencing) resulting in 1.34M reads with an average read length of 492 base pairs. 40,994 isotigs were identified, averaging 1188 bp with a median coverage of 11×. Additional primer design and gap sequencing were required to complete the mitochondrial genome. The mitogenome of S. neumayeri is a circular DNA molecule with a length of 15 684 bp that contains all 37 genes normally found in metazoans. We detail the main features of the transcriptome and the mitogenome architecture and investigate the phylogenetic relationships of S. neumayeri within Echinoidea. In addition, we provide comparative analyses of S. neumayeri with its closest relative, Strongylocentrotus purpuratus, including a list of potential OA gene targets. The resources described here will support a variety of quantitative (genomic, proteomic, multistress and comparative) studies to interrogate physiological responses to OA and other stressors in this important Antarctic calcifier.
Publisher: Elsevier BV
Date: 06-2013
DOI: 10.1016/J.CBPA.2013.03.002
Abstract: The strong dependence of metabolic rates on body mass has attracted the interest of ecological physiologists, as it has important implications to many aspects of biology including species variations in body size, the evolution of life history, and the structure and function of biological communities. The great ersity of observed scaling exponents has led some authors to conclude that there is no single universal scaling exponent, but instead it ranges from 2/3 to 1. Most of the telling evidence against the universality of power scaling exponents comes from ontogenetic changes. Nevertheless, there could be other sources of phenotypic variation that influence this allometric relationship at least at the intraspecific level. In order to explore the general concept of the metabolic scaling in terrestrial molluscs we tested the role of several biological and methodological sources of variation on the empirically estimated scaling exponent. Specifically, we measured a proxy of metabolic rate (CO(2) production) in 421 in iduals, during three generations, in three different populations. Additionally, we measured this scaling relationship in 208 in iduals at five developmental stages. Our results suggest that the metabolic scaling exponent at the intraspecific level does not have a single stationary value, but instead it shows some degree of variation across geographic distribution, transgenerational change and ontogenetic stages. The major differences in the metabolic scaling exponent that we found were at different developmental stages of snails, because ontogeny involves increases in size at different rates, which in turn, generate differential energy demands.
Publisher: The Royal Society
Date: 02-2017
Abstract: Geographical gradients in selection can shape different genetic architectures in natural populations, reflecting potential genetic constraints for adaptive evolution under climate change. Investigation of natural pH/ p CO 2 variation in upwelling regions reveals different spatio-temporal patterns of natural selection, generating genetic and phenotypic clines in populations, and potentially leading to local adaptation, relevant to understanding effects of ocean acidification (OA). Strong directional selection, associated with intense and continuous upwellings, may have depleted genetic variation in populations within these upwelling regions, favouring increased tolerances to low pH but with an associated cost in other traits. In contrast, ersifying or weak directional selection in populations with seasonal upwellings or outside major upwelling regions may have resulted in higher genetic variances and the lack of genetic correlations among traits. Testing this hypothesis in geographical regions with similar environmental conditions to those predicted under climate change will build insights into how selection may act in the future and how populations may respond to stressors such as OA.
Publisher: University of Chicago Press
Date: 09-2013
DOI: 10.1086/672092
Abstract: Life-history evolution-the way organisms allocate time and energy to reproduction, survival, and growth-is a central question in evolutionary biology. One of its main tenets, the allocation principle, predicts that selection will reduce energy costs of maintenance in order to ert energy to survival and reproduction. The empirical support for this principle is the existence of a negative relationship between fitness and metabolic rate, which has been observed in some ectotherms. In juvenile animals, a key function affecting fitness is growth rate, since fast growers will reproduce sooner and maximize survival. In principle, design constraints dictate that growth rate cannot be reduced without affecting maintenance costs. Hence, it is predicted that juveniles will show a positive relationship between fitness (growth rate) and metabolic rate, contrarily to what has been observed in adults. Here we explored this problem using land snails (Cornu aspersum). We estimated the additive genetic variance-covariance matrix for growth and standard metabolic rate (SMR rate of CO2 production) using 34 half-sibling families. We measured eggs, hatchlings, and juveniles in 208 offspring that were isolated right after egg laying (i.e., minimizing maternal and common environmental variance). Surprisingly, our results showed that additive genetic effects (narrow-sense heritabilities, h(2)) and additive genetic correlations (rG) were small and nonsignificant. However, the nonadditive proportion of phenotypic variances and correlations (rC) were unexpectedly large and significant. In fact, nonadditive genetic effects were positive for growth rate and SMR ([Formula: see text] [Formula: see text]), supporting the idea that fitness (growth rate) cannot be maximized without incurring maintenance costs. Large nonadditive genetic variances could result as a consequence of selection eroding the additive genetic component, which suggests that past selection could have produced nonadditive genetic correlation. It is predicted that this correlation is reduced when adulthood is attained and selection starts to promote the reduction in metabolic rate.
Publisher: Informa UK Limited
Date: 14-04-2016
DOI: 10.3109/19401736.2014.908359
Abstract: The complete mitochondrial genome of the Californian giant red sea urchin Mesocentrotus franciscanus has been determined. It has a length of 15,650 bp and contains the same 37 genes found in other metazoans (13 protein-coding genes, 22 tRNA genes, and two rRNA genes). Only five tRNA genes and the Nad6 gene are coded on the minus strand. There were 14 identified small intergene regions (2 to 24 bp) and a large non-coding region (125 bp) located between the tRNA-T and tRNA-P. The overall base composition of this genome is 29.8% A, 27.6% T, 29.7% C, and 17.5% G, with a slight A + T bias of 59.4%. The most frequent start codon is ATG (11 genes) whereas TAA is the most frequent stop codon (10 genes). Overall, gene arrangement pattern, gene content and genome organization is similar to other echinoids.
Publisher: Springer Science and Business Media LLC
Date: 07-2023
Publisher: CRC Press
Date: 22-09-2021
Publisher: Wiley
Date: 07-05-2023
DOI: 10.1002/LNO.12367
Abstract: It is commonly known that phytoplankton have a pivotal role in marine biogeochemistry and ecosystems as carbon fixers and oxygen producers, but their response to deoxygenation has scarcely been studied. Nonetheless, in the major oceanic oxygen minimum zones (OMZs), all surface phytoplankton groups, regardless of size, disappear and are replaced by unique cyanobacteria lineages below the oxycline. To develop reasonable hypotheses to explain this pattern, we conduct a review of available information on OMZ phytoplankton, and we re‐analyze previously published data (flow cytometric and hydrographic) on vertical structure of phytoplankton communities in relation to light and O 2 levels. We also review the physical constraints on O 2 acquisition as well as O 2 ‐dependent metabolisms in phototrophs. These considerations, along with estimates of the photosynthetic capacity of phytoplankton along OMZ depth profiles using published data, suggest that top‐down grazing, respiratory demand, and irradiance are insufficient to fully explain the vertical structure observed in the upper, more sunlit portions of OMZs. Photorespiration and water–water cycles are O 2 ‐dependent pathways with low O 2 affinities. Although their metabolic roles are still poorly understood, a hypothetical dependence on such pathways by the phytoplankton adapted to the oxic ocean might explain vertical patterns in OMZs and results of laboratory experiments. This can be represented in a simple model in which the requirement for photorespiration in surface phytoplankton and O 2 ‐inhibition of OMZ lineages reproduces the observed vertical fluorescence profiles and the replacement of phytoplankton adapted to O 2 by lineages restricted to the most O 2 ‐deficient waters. A high O 2 requirement by modern phytoplankton would suggest a positive feedback that intensifies trends in OMZ extent and ocean oxygenation or deoxygenation, both in Earth's past and in response to current climate change.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Wiley
Date: 11-2018
DOI: 10.1111/MEC.14876
Abstract: The small South American marsupial, Dromiciops gliroides, known as the missing link between the American and the Australian marsupials, is one of the few South American mammals known to hibernate. Expressing both daily torpor and seasonal hibernation, this species may provide crucial information about the mechanisms and the evolutionary origins of marsupial hibernation. Here, we compared torpid and active in iduals, applying high-throughput sequencing technologies (RNA-seq) to profile gene expression in three D. gliroides tissues and determine whether hibernation induces tissue-specific differential gene expression. We found 566 transcripts that were significantly up-regulated during hibernation (369 in brain, 147 in liver and 50 in skeletal muscle) and 339 that were down-regulated (225 in brain, 79 in liver and 35 in muscle). The proteins encoded by these differentially expressed genes orchestrate multiple metabolic changes during hibernation, such as inhibition of angiogenesis, prevention of muscle disuse atrophy, fuel switch from carbohydrate to lipid metabolism, protection against reactive oxygen species and repair of damaged DNA. According to the global enrichment analysis, brain cells seem to differentially regulate a complex array of biological functions (e.g., cold sensitivity, circadian perception, stress response), whereas liver and muscle cells prioritize fuel switch and heat production for rewarming. Interestingly, transcripts of thioredoxin-interacting protein (TXNIP), a potent antioxidant, were significantly over-expressed during torpor in all three tissues. These results suggest that marsupial hibernation is a controlled process where selected metabolic pathways show adaptive modulation that can help to maintain homeostasis and enhance cytoprotection in the hypometabolic state.
Publisher: Cambridge University Press
Date: 22-06-2022
Publisher: The Royal Society
Date: 02-2017
Abstract: Phenotypic plasticity is expected to play a major adaptive role in the response of species to ocean acidification (OA), by providing broader tolerances to changes in p CO 2 conditions. However, tolerances and sensitivities to future OA may differ among populations within a species because of their particular environmental context and genetic backgrounds. Here, using the climatic variability hypothesis (CVH), we explored this conceptual framework in populations of the sea urchin Loxechinus albus across natural fluctuating p CO 2 H environments. Although elevated p CO 2 affected the morphology, physiology, development and survival of sea urchin larvae, the magnitude of these effects differed among populations. These differences were consistent with the predictions of the CVH showing greater tolerance to OA in populations experiencing greater local variation in seawater p CO 2 H. Considering geographical differences in plasticity, tolerances and sensitivities to increased p CO 2 will provide more accurate predictions for species responses to future OA.
Publisher: Springer Science and Business Media LLC
Date: 31-05-2016
DOI: 10.1038/SREP26853
Abstract: Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere ( M. trossulus , M. edulis , M. galloprovincialis , M. californianus and M. coruscus ) and three in the Southern Hemisphere ( M. galloprovincialis , M. chilensis and M. platensis ). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another from the Pacific M. chilensis . These mitogenomes exhibited similar architecture to those of other genomes of Mytilus , including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic ergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species.
Publisher: Springer Science and Business Media LLC
Date: 10-03-2016
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.YMPEV.2018.10.036
Abstract: Mitochondrial genomes (mitogenomes) provide valuable phylogenetic information and genome-level characters that are useful in resolving evolutionary relationships within major lineages of gastropods. However, for more than one decade, these relationships and the phylogenetic position of Patellogastropoda have been inferred based on the genomic architecture as well as the nucleotide and protein sequences of a single representative, the limpet Lottia digitalis. This mitogenome exhibits extensive rearrangements and several repetitive units that may not represent universal features for Patellogastropoda. Here, we sequenced the complete mitogenomes of three Nacella limpets, providing new insights into the dynamics of gene order and phylogenetic relationships of Patellogastropoda. Comparative analyses revealed novel gene rearrangements in Gastropoda, characterised by two main translocations that affect the KARNI and the MYCWQ clusters in Nacella limpets. Our phylogenetic reconstructions using combined sequence datasets of 13 mitochondrial protein-coding genes and two rRNAs, recovered Patellogastropoda, and Gastropoda in general, as non-monophyletic. These findings could be related to the long-branch attraction tendency of these groups, and/or taxon s ling bias. In our novel mitogenome-based phylogenetic hypothesis, L. digitalis is placed in a sister position to Bivalvia and Heterobranchia, whereas Nacella limpets are placed sister to a clade containing Caenogastropoda + Neritimorpha and Vetigastropoda + Neomphalina.
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2017
DOI: 10.1101/191825
Abstract: This preprint has been reviewed and recommended by Peer Community In Evolutionary Biology ( 0.24072 ci.evolbiol.100048 ). For ectothermic species with broad geographical distributions, latitudinal/altitudinal variation in environmental temperatures (averages and extremes) are expected to shape the evolution of physiological tolerances and the acclimation capacity (i.e., degree of phenotypic plasticity) of natural populations. This can create geographical gradients of selection in which environments with greater thermal variability (e.g., seasonality) tend to favour in iduals that maximize performance across a broader range of temperatures compared to more stable environments. Although thermal acclimation capacity plays a fundamental role in this context, it is unknown whether natural selection targets this trait in natural populations. Here we addressed such an important gap in our knowledge by measuring survival, through mark recapture integrated into an information-theoretic approach, as a function of the plasticity of critical thermal limits for activity, behavioural thermal preference and the thermal sensitivity of metabolism in the northernmost population of the four-eyed frog Pleurodema thaul . Overall, our results indicate that thermal acclimation in this population is not being targeted by directional selection, although there might be signals of selection on in idual traits. According to the most supported models, survival decreased in in iduals with less tolerance to cold when cold-acclimated (probably because daily low extremes are frequent during the cooler periods of the year) and increased with body size. However, in both cases, the directional selection estimates were non-significant.
Publisher: SciELO Agencia Nacional de Investigacion y Desarrollo (ANID)
Date: 04-2011
Publisher: Springer Science and Business Media LLC
Date: 19-04-2016
DOI: 10.1038/SREP24627
Abstract: When faced with adverse environmental conditions, the marsupial Dromiciops gliroides uses either daily or seasonal torpor to support survival and is the only known hibernating mammal in South America. As the sole living representative of the ancient Order Microbiotheria, this species can provide crucial information about the evolutionary origins and biochemical mechanisms of hibernation. Hibernation is a complex energy-saving strategy that involves changes in gene expression that are elicited in part by microRNAs. To better elucidate the role of microRNAs in orchestrating hypometabolism, a modified stem-loop technique and quantitative PCR were used to characterize the relative expression levels of 85 microRNAs in liver and skeletal muscle of control and torpid D. gliroides . Thirty-nine microRNAs were differentially regulated during torpor of these, 35 were downregulated in liver and 11 were differentially expressed in skeletal muscle. Bioinformatic analysis predicted that the downregulated liver microRNAs were associated with activation of MAPK, PI3K-Akt and mTOR pathways, suggesting their importance in facilitating marsupial torpor. In skeletal muscle, hibernation-responsive microRNAs were predicted to regulate focal adhesion, ErbB, and mTOR pathways, indicating a promotion of muscle maintenance mechanisms. These tissue-specific responses suggest that microRNAs regulate key molecular pathways that facilitate hibernation, thermoregulation, and prevention of muscle disuse atrophy.
Publisher: Springer International Publishing
Date: 2020
Publisher: Wiley
Date: 24-06-2015
Publisher: The Royal Society
Date: 28-01-2019
Abstract: Climate change is leading to shifts in species geographical distributions, but populations are also probably adapting to environmental change at different rates across their range. Owing to a lack of natural and empirical data on the influence of phenotypic adaptation on range shifts of marine species, we provide a general conceptual model for understanding population responses to climate change that incorporates plasticity and adaptation to environmental change in marine ecosystems. We use this conceptual model to help inform where within the geographical range each mechanism will probably operate most strongly and explore the supporting evidence in species. We then expand the discussion from a single-species perspective to community-level responses and use the conceptual model to visualize and guide research into the important yet poorly understood processes of plasticity and adaptation. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.
Publisher: Pontificia Universidad Catolica de Valparaiso
Date: 31-05-2008
Publisher: Public Library of Science (PLoS)
Date: 05-08-2013
Publisher: Springer Science and Business Media LLC
Date: 21-02-2020
DOI: 10.1038/S41598-020-60104-4
Abstract: Local and global changes associated with anthropogenic activities are impacting marine and terrestrial ecosystems. Macroalgae, especially habitat-forming species like kelp, play critical roles in temperate coastal ecosystems. However, their abundance and distribution patterns have been negatively affected by warming in many regions around the globe. Along with global change, coastal ecosystems are also impacted by local drivers such as eutrophication. The interaction between global and local drivers might modulate kelp responses to environmental change. This study examines the regulatory effect of NO 3 − on the thermal plasticity of the giant kelp Macrocystis pyrifera . To do this, thermal performance curves (TPCs) of key temperature-dependant traits–growth, photosynthesis, NO 3 − assimilation and chlorophyll a fluorescence–were examined under nitrate replete and deplete conditions in a short-term incubation. We found that thermal plasticity was modulated by NO 3 − but different thermal responses were observed among traits. Our study reveals that nitrogen, a local driver, modulates kelp responses to high seawater temperatures, ameliorating the negative impacts on physiological performance (i.e. growth and photosynthesis). However, this effect might be species-specific and vary among biogeographic regions – thus, further work is needed to determine the generality of our findings to other key temperate macroalgae that are experiencing temperatures close to their thermal tolerance due to climate change.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Wiley
Date: 09-10-2018
DOI: 10.1111/EVA.12702
Publisher: Springer Science and Business Media LLC
Date: 17-07-2013
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.005
Abstract: The South American marsupial, monito del monte (Dromiciops gliroides) uses both daily torpor and multi-day hibernation to survive in its southern Chile native environment. The present study leverages multiplex technology to assess the contributions of key stress-inducible cell cycle regulators and heat shock proteins to hibernation in liver, heart, and brain of monito del monte in a comparison of control versus 4day hibernating conditions. The data indicate that MDM2, a stress-responsive ubiquitin ligase, plays a crucial role in marsupial hibernation since all three tissues showed statistically significant increases in MDM2 levels during torpor (1.6-1.8 fold). MDM2 may have a cytoprotective action to deal with ischemia/reperfusion stress and is also involved in a nutrient sensing pathway where it could help regulate the metabolic switch to fatty acid oxidation during torpor. Elevated levels of stress-sensitive cell cycle regulators including ATR (2.32-3.91 fold), and the phosphorylated forms of p-Chk1 (Ser345) (1.92 fold), p-Chk2 (Thr68) (2.20 fold) and p21 (1.64 fold) were observed in heart and liver during hibernation suggesting that the cell cycle is likely suppressed to conserve energy while animals are in torpor. Upregulation of heat shock proteins also occurred as a cytoprotective strategy with increased levels of hsp27 (2.00 fold) and hsp60 (1.72-2.76 fold) during hibernation. The results suggest that cell cycle control and selective chaperone action are significant components of hibernation in D. gliroides and reveal common molecular responses to those seen in eutherian hibernators.
Publisher: Wiley
Date: 18-04-2017
DOI: 10.1002/ECE3.2957
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.006
Abstract: When faced with harsh environmental conditions, the South American marsupial, monito del monte (Dromiciops gliroides), reduces its body temperature and uses either daily torpor or multiday hibernation to survive. This study used ELISA and multiplex assays to characterize the responses to hibernation by three regulatory components of protein translation machinery [p-eIF2α(S51), p-eIF4E(S209), p-4EBP(Thr37/46)] and eight targets involved in upstream signaling control of translation [p-IGF-1R(Tyr1135/1136), PTEN(S380), p-Akt(S473), p-GSK-3α(S21), p-GSK-3β(S9), p-TSC2(S939), p-mTOR(S2448), and p70S6K(T412)]. Liver, brain and kidney were analyzed comparing control and hibernation (4days continuous torpor) conditions. In the liver, increased phosphorylation of IGF-1R, Akt, GSK-3β, TSC2, mTOR, eIF2α, and 4EBP (1.60-1.98 fold compared to control) occurred during torpor suggesting that the regulatory phosphorylation cascade and protein synthesis remained active during torpor. However, responses by brain and kidney differed torpor resulted in increased phosphorylation of GSK-3β (2.15-4.17 fold) and TSC2 (2.03-3.65 fold), but phosphorylated Akt decreased (to 34-62% of control levels). Torpor also led to an increase in phosphorylated eIF2α (1.4 fold) content in the brain. These patterns of differential protein phosphorylation in brain and kidney were indicative of suppression of protein translation but also could suggest an increase in antioxidant and anti-apoptotic signaling during torpor. Previous studies of liver metabolism in hibernating eutherian mammals have shown that Akt kinase and its downstream signaling components play roles in facilitating hypometabolism by suppressing energy expensive anabolic processes during torpor. However, the results in this study reveal differences between eutherian and marsupial hibernators, suggesting alternative actions of liver Akt during torpor.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.007
Abstract: Hibernation is a period of torpor and heterothermy that is typically associated with a strong reduction in metabolic rate, global suppression of transcription and translation, and upregulation of various genes roteins that are central to the cellular stress response such as protein kinases, antioxidants, and heat shock proteins. The current study examined cell signaling cascades in hibernating monito del monte, Dromiciops gliroides, a South American marsupial of the Order Microbiotheria. Responses to hibernation by members of the mitogen-activated protein kinase (MAPK) pathways, and their roles in coordinating hibernator metabolism were examined in liver, kidney, heart and brain of control and versus hibernating (4days continuous torpor) D. gliroides. The targets evaluated included key protein kinases in their activated phosphorylated forms (p-ERK/MAPK 1/2, p-MEK1, p-MSK1, p-p38, p-JNK) and related target proteins (p-CREB 2, p-ATF2, p-c-Jun and p-p53). Liver exhibited a strong coordinated response by MAPK members to hibernation with significant increases in protein phosphorylation levels of p-MEK1, p-ERK/MAPK1/2, p-MSK1, p-JNK and target proteins c-Jun, and p-ATF2, all combining to signify a strong activation of MAPK signaling during hibernation. Kidney also showed activation of MAPK cascades with significant increases in p-MEK1, p-ERK/MAPK1/2, p-p38, and p-c-Jun levels in hibernating animals. By contrast, responses by heart and brain indicated reduced MAPK pathway function during torpor with reduced phosphorylation of targets including p-ERK/MAPK 1/2 in both tissues as well as lower p-p38 and p-JNK content in heart. Overall, the data indicate a vital role for MAPK signaling in regulating the cell stress response during marsupial hibernation.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.008
Abstract: Mammalian hibernation is characterized by extensive adjustments to metabolism that typically include suppression of carbohydrate catabolism and a switch to triglycerides as the primary fuel during torpor. A crucial locus of control in this process is the pyruvate dehydrogenase complex that gates carbohydrate entry into the tricarboxylic acid cycle. Within the complex, the E1 enzyme pyruvate dehydrogenase (PDH) is the main regulatory site and is subject to inhibitory phosphorylation at three serine residues (S232, S293, S300). To determine if marsupial hibernators show a comparable focus on PDH to regulate fuel metabolism, the current study explored PDH control by site-specific phosphorylation in the South American marsupial, monito del monte (Dromiciops gliroides). Luminex multiplex technology was used to analyze PDH responses in six tissues comparing control and hibernating (4days continuous torpor) animals. Total PDH content did not change significantly during hibernation in any tissue but phospho-PDH content increased in all. Heart PDH showed increased phosphorylation at all three sites by 8.1-, 10.6- and 2.1-fold for S232, S293 and S300, respectively. Liver also showed elevated p-S300 (2.5-fold) and p-S293 (4.7-fold) content. Phosphorylation of S232 and S293 increased significantly in brain and lung but only S232 phosphorylation increased in kidney and skeletal muscle. The results show that PDH suppression via enzyme phosphorylation during torpor is a conserved mechanism for inhibiting carbohydrate catabolism in both marsupial and eutherian mammals, an action that would also promote the switch to fatty acid oxidation instead.
Publisher: Public Library of Science (PLoS)
Date: 24-06-2013
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.MARGEN.2019.05.007
Abstract: The red sea urchin, Mesocentrotus franciscanus, is an ecologically important kelp forest species that also serves as a valuable fisheries resource. In this study, we have assembled and annotated a developmental transcriptome for M. franciscanus that represents eggs and six stages of early development (8- to 16-cell, morula, hatched blastula, early gastrula, prism and early pluteus). Characterization of the transcriptome revealed distinct patterns of gene expression that corresponded to major developmental and morphological processes. In addition, the period during which maternally-controlled transcription was terminated and the zygotic genome was activated, the maternal-to-zygotic transition (MZT), was found to begin during early cleavage and persist through the hatched blastula stage, an observation that is similar to the timing of the MZT in other sea urchin species. The presented developmental transcriptome will serve as a useful resource for investigating, in both an ecological and fisheries context, how the early developmental stages of this species respond to environmental stressors.
Publisher: Elsevier BV
Date: 08-2014
Publisher: Elsevier BV
Date: 03-2013
Publisher: Springer Science and Business Media LLC
Date: 06-01-2021
Start Date: 04-2020
End Date: 04-2025
Amount: $350,000.00
Funder: Australian Research Council
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