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Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

Deregulation of interferon-gamma receptor 1 expression and its implications for lung adenocarcinoma progression

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World Journal of Clinical Oncology 2024年第2期15卷 195-207页

作者： Angeles C Tecalco-Cruz Karen H Medina-Abreu Enrique Oropeza-Martínez Jesus Zepeda-Cervantes AleidaVázquez-macías Marina macías-Silva Posgrado en Ciencias Genómicas Universidad Autónoma de la Ciudad de MéxicoCDMX 03100Mexico Facultad de Medicina Veterinaria y Zootecnia Universidad Nacional Autónoma de MéxicoCDMX 04510Mexico Colegio de Ciencias y Humanidades Universidad Autónoma de la Ciudad de MéxicoCDMX 03100Mexico Instituo de Fisiología Celular Universidad Nacional Autónoma de MéxicoCDMX 04510Mexico

Interferon-gamma(IFN-γ)plays a dual role in cancer;it is both a pro-and an antitumorigenic cytokine,depending on the type of cancer.The deregulation of the IFN-γcanonic pathway is associated with several disorders,including vulner-ability to viral infections,inflammation,and cancer progression.In particular,the interplay between lung adenocarcinoma(LUAD)and viral infections appears to exist in association with the deregulation of IFN-γsignaling.In this mini-review,we investigated the status of the IFN-γsignaling pathway and the expression level of its components in LUAD.Interestingly,a reduction in IFNGR1 expression seems to be associated with LUAD progression,affecting defenses against viruses such as severe acute respiratory syndrome coronavirus 2.In addition,alterations in the expression of IFNGR1 may inhibit the antiproliferative action of IFN-γsignaling in LUAD.

关键词： Interferon-gamma IFNGR1 JAK1 Antiviral Anti-tumor Lung adenocarcinoma

Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： david J.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Exercise immunology:Novel insights

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Journal of Sport and Health Science 2024年第3期13卷 277-279,I0001页

作者： david C.Nieman Human Performance Laboratory Appalachian State UniversityNorth Carolina Research CampusKannapolisNC 28081USA

The coronavirus disease 2019(COVID-19)pandemic heightened worldwide attention on the influence of exercise on the immune system.Questions were raised about whether regular moderate-to-vigorous physical activity(MVPA)could help prevent COVID-19 or mitigate symptoms when ill.Could MVPA bolster immunity among those most prone to COVID-19 including the elderly,obese,and immunocompromised patients?Does regular MVPA dampen systemic inflammation,thereby lessening the COVID-19 cytokine storm?

关键词： immunity inflammation thereby

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One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

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Kerogen Kinetic Distributions and Simulations Provide Insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

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Journal of Earth Science 2024年第3期35卷 747-757页

作者： david A.Wood DWA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·min-1.The activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and kerogens.The characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A trend.Important similarities and differences are observed between the TF profile values of the two datasets.The similarities support the spread of E-A values involved in shale pyrogram best fits.The differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions simulated.The results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A values.In contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale formations.TF profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

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Role of climatic variability in shaping intraspecific variation of thermal tolerance in Mediterranean water beetles

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Insect Science 2024年第1期31卷 285-298页

作者： Susana Pallarés david Garoffolo Belén Rodríguez david Sánchez-Fernández Department of Zoology University of SevilleSevilleSpain Faculty of Biology Department of Ecology and HydrologyUniversity of MurciaCampus EspinardoMurciaSpain

The climatic variability hypothesis(CVH)predicts that organisms in more thermally variable environments have wider thermal breadths and higher thermal plasticity than those from more stable environments.However,due to evolutionary trade-offs,taxa with greater absolute thermal limits may have little plasticity of such limits(trade-off hypothesis).The CVH assumes that climatic variability is the ultimate driver of thermal tolerance variation across latitudinal and altitudinal gradients,but average temperature also varies along such gradients.We explored intraspecific variation of thermal tolerance in three typical Mediterranean saline water beetles(families Hydrophilidae and Dytiscidae).For each species,we compared two populations where the species coexist,with similar annual mean temperature but contrasting thermal variability(continental vs.coastal population).We estimated thermal limits of adults from each population,previously acclimated at 17,20,or 25℃.We found species-specific patterns but overall,our results agree with the CVH regarding thermal ranges,which were wider in the continental(more variable)population.In the two hydrophilid species,this came at the cost of losing plasticity of the upper thermal limit in this population,supporting the trade-off hypothesis,but not in the dytiscid one.Our results support the role of local adaptation to thermal variability and trade-offs between basal tolerance and physiological plasticity in shaping thermal tolerance in aquatic ectotherms,but also suggest that intraspecific variation of thermal tolerance does not fit a general pattern among aquatic insects.Overlooking such intraspecific variation could lead to inaccurate predictions of the vulnerability of aquatic insects to global warming.

关键词： acclimation capacity aquatic insects climate change heat coma temperature supercooling point thermal plasticity

The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall david P.G.Bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high temperatures.Other kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Cultivating potential:Harnessing plant stem cells for agricultural crop improvement

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Molecular Plant 2024年第1期17卷 50-74页

作者： Penelope Lindsay Kyle W.Swentowsky david Jackson Cold Spring Harbor Laboratory Cold Spring HarborNY 11724USA National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhanHubei430070China

Meristems are stem cell-containing structures that produce all plant organs and are therefore important targets for crop improvement.Developmental regulators control the balance and rate of cell divisions within the meristem.Altering these regulators impacts meristem architecture and,as a consequence,plant form.In this review,we discuss genes involved in regulating the shoot apical meristem,inflorescence meristem,axillary meristem,root apical meristem,and vascular cambium in plants.We highlight several examples showing how crop breeders have manipulated developmental regulators to modify meristem growth and alter crop traits such as inflorescence size and branching patterns.Plant transformation techniques are another innovation related to plant meristem research because they make crop genome engineering possible.We discuss recent advances on plant transformation made possible by studying genes controlling meristem development.Finally,we conclude with discussions about how meristem research can contribute to crop improvement in the coming decades.

关键词： meristem crop improvement plant transformation plant breeding crop yield gene editing