The global expansion of toxic Microcystis blooms, and production of cyanotoxins including microcystins, are an increasing risk to freshwater fish. Differentiating intracellular and extracellular ...microcystin toxicity pathways (i.e., within and outside of cyanobacterial cells) in fish is necessary to assess the severity of risks to populations that encounter harmful algal blooms in pre-to-postsenescent stages. To address this, adult and juvenile Rainbow Trout (Oncorhynchus mykiss) were, respectively, exposed for 96 h to intracellular and extracellular microcystins (0, 20, and 100 μg L–1) produced by Microcystis aeruginosa. Fish were dissected at 24 h intervals for histopathology, targeted microcystin quantification, and nontargeted proteomics. Rainbow Trout accumulated intracellular and extracellular microcystins in all tissues within 24 h, with greater accumulation in the extracellular state. Proteomics revealed intracellular and extracellular microcystins caused sublethal toxicity by significantly dysregulating proteins linked to the cytoskeletal structure, stress responses, and DNA repair in all tissues. Pyruvate metabolism in livers, anion binding in kidneys, and myopathy in muscles were also significantly impacted. Histopathology corroborated these findings with evidence of necrosis, apoptosis, and hemorrhage at similar severity in both microcystin treatments. We demonstrate that sublethal concentrations of intracellular and extracellular microcystins cause adverse effects in Rainbow Trout after short-term exposure.
Attenuated evolution of mammals through the Cenozoic Goswami, Anjali; Noirault, Eve; Coombs, Ellen J. ...
Science (American Association for the Advancement of Science),
10/2022, Letnik:
378, Številka:
6618
Journal Article
Recenzirano
Odprti dostop
The Cenozoic diversification of placental mammals is the archetypal adaptive radiation. Yet, discrepancies between molecular divergence estimates and the fossil record fuel ongoing debate around the ...timing, tempo, and drivers of this radiation. Analysis of a three-dimensional skull dataset for living and extinct placental mammals demonstrates that evolutionary rates peak early and attenuate quickly. This long-term decline in tempo is punctuated by bursts of innovation that decreased in amplitude over the past 66 million years. Social, precocial, aquatic, and herbivorous species evolve fastest, especially whales, elephants, sirenians, and extinct ungulates. Slow rates in rodents and bats indicate dissociation of taxonomic and morphological diversification. Frustratingly, highly similar ancestral shape estimates for placental mammal superorders suggest that their earliest representatives may continue to elude unequivocal identification.
Becoming diverse
Mammals have the greatest degree of morphological variation among vertebrate classes, ranging from giant whales to the tiny bumblebee bat. How they evolved this level of variation has been a persistent question, with much debate being centered around the timing and tempo of evolutionary change. Goswami
et al
. looked across a large dataset of extinct and extant mammalian skulls and found that the rate of evolutionary change peaked around the time of the Cretaceous-Paleogene boundary and has general tapered off since then (see the Perspective by Santana and Grossnickle). Certain lifestyles, such as aquatic habitats or herbivory, led to faster change, whereas in some species such as rodents, morphological change appeared to be decoupled from taxonomic diversification. —SNV
Short bursts of innovation have punctuated a long-term decline in the rate of placental mammal skull evolution over the past 66 million years.
Species that are geographically widespread may exist across environmentally heterogeneous landscapes that could influence patterns of occupation and phylogeographic structure. Previous studies have ...suggested that geographic range size should be positively correlated with niche breadth, allowing widespread species to sustain viable populations over diverse environmental gradients. We examined the congruence of phenotypic and phylogenetic divergence with the environmental factors that help maintain species level diversity in the geographically widespread hoary bats (Lasiurus cinereus sensu lato) across their distribution. Genetic sequences were analyzed using multiple phylogenetic and species delimitation methods, and phenotypic data were analyzed using supervised and unsupervised machine learning approaches. Spatial data from environmental, geographic, and topographic features were analyzed in a multiple regression analysis to determine their relative effect on phenotypic diversity. Ecological niches of each hoary bat species were examined in environmental space to quantify niche overlap, equivalency, and the magnitude of niche differentiation. Phylogenetic and species delimitation analyses support existence of three geographically structured species of hoary bat, each of which is phenotypically distinct. However, the Hawaiian hoary bat is morphologically more similar to the South American species than to the North American species despite a closer phylogenetic relationship to the latter. Multiple regression and niche analyses revealed higher environmental similarities between the South American and Hawaiian species. Hoary bats thus exhibit a pattern of phenotypic variation that disagrees with well-supported genetic divergences, instead indicating phenotypic convergence driven by similar environmental features and relatively conserved niches occupied in tropical latitudes.
Understanding how private landholders make deforestation decisions is of paramount importance for conservation. Behavioural frameworks from the social sciences have a lot to offer researchers and ...practitioners, yet these insights remain underutilised in describing what drives landholders’ deforestation intentions under important political, social, and management contexts. Using survey data of private landholders in Queensland, Australia, we compare the ability of two popular behavioural models to predict future deforestation intentions, and propose a more integrated behavioural model of deforestation intentions. We found that the integrated model outperformed other models, revealing the importance of threat perceptions, attitudes, and social norms for predicting landholders’ deforestation intentions. Social capital, policy uncertainty, and years of experience are important contextual moderators of these psychological factors. We conclude with recommendations for promoting behaviour change in this deforestation hotspot and highlight how others can adopt similar approaches to illuminate more proximate drivers of environmental behaviours in other contexts.
Abstract
Does the environment of a galaxy directly influence the quenching history of a galaxy? Here, we investigate the detailed morphological structures and star formation histories of a sample of ...SDSS group galaxies with both classifications from Galaxy Zoo 2 and near ultra-violet (NUV) detections in GALEX. We use the optical and NUV colours to infer the quenching time and rate describing a simple exponentially declining star formation history for each galaxy, along with a control sample of field galaxies. We find that the time since quenching and the rate of quenching do not correlate with the relative velocity of a satellite but are correlated with the group potential. This quenching occurs within an average quenching time-scale of ∼ 2.5 Gyr from star forming to complete quiescence, during an average infall time (from ∼10R
200 to 0.01R
200) of ∼ 2.6 Gyr. Our results suggest that the environment does play a direct role in galaxy quenching through quenching mechanisms that are correlated with the group potential, such as harassment, interactions or starvation. Environmental quenching mechanisms that are correlated with satellite velocity, such as ram-pressure stripping, are not the main cause of quenching in the group environment. We find that no single mechanism dominates over another, except in the most extreme environments or masses. Instead, an interplay of mergers, mass and morphological quenching and environment-driven quenching mechanisms dependent on the group potential drive galaxy evolution in groups.
China is now the world's largest source of bilateral development finance and will likely continue to play a prominent role in sovereign lending through its multi-billion-dollar Belt and Road ...Initiative. This paper introduces major methodological enhancements in tracking this finance: the use of an original application programming interface (API) to gathers news in multiple languages; double-verification of every record to ensure every finance commitment has been formalized; and visual geo-location to trace the precise footprint of every project. The resulting dataset enables economic, environmental, and social analyses with high-precision spatial accuracy, as well as spatiotemporal monitoring by project stakeholders and enhanced planning by project managers. It covers the years 2008-2019 to enable analysis before and after the announcement of the Belt and Road Initiative. It includes 862 finance commitments, 669 of which have geographic location, to 94 countries across the world.
Voluntary private land conservation (PLC) is becoming an increasingly important complement to state protected areas around the world. PLC programs can serve as valuable strategies to increase ...biodiversity on agricultural lands, but their effectiveness depends on high participation rates. Amidst growing concerns regarding scalability and effectiveness of conservation strategies like national parks, researchers and practitioners are looking for new strategies to increase adoption of PLC. This study investigates the demographic, social, and psychological factors associated with participation in three classes of voluntary PLC programs—grant payments, land management agreements, and covenants—and how this relates to landholders’ attitudes toward tree clearing. We compare participation rates between these programs in Queensland and identify the most frequently cited reasons why land managers have or have not participated. Land managers who are more involved in agricultural organizations and whose tree clearing decisions are more influenced by the aesthetic value of trees are more likely to have participated in one or more of these programs. Participation was highly biased toward once-off grant payments, and participation in covenants was lowest of all programs. Although 58% of land managers have never participated, nearly half expressed interest in one or more programs. A lack of program knowledge and perceived losses of autonomy were the most frequently cited barriers to participation. We conclude with recommendations for increasing participation rates and raise important questions that need to be answered in order to promote a PLC culture that effectively curbs ongoing habitat degradation.
While major mergers have long been proposed as a driver of both active galactic nucleus (AGN) activity and the relation, studies of moderate to high-redshift Seyfert-luminosity AGN hosts have found ...little evidence for enhanced rates of interactions. However, both theory and observation suggest that while these AGNs may be fueled by stochastic accretion and secular processes, high-luminosity, high-redshift, and heavily obscured AGNs are the AGNs most likely to be merger-driven. To better sample this population of AGNs, we turn to infrared selection in the CANDELS/COSMOS field. Compared to their lower-luminosity and less obscured X-ray-only counterparts, IR-only AGNs (luminous, heavily obscured AGNs) are more likely to be classified as either irregular ( versus ) or asymmetric ( versus ) and are less likely to have a spheroidal component ( versus ). Furthermore, IR-only AGNs are also significantly more likely than X-ray-only AGNs ( versus ) to be classified either as interacting or merging in a way that significantly disturbs the host galaxy or as disturbed, though not clearly interacting or merging, which potentially represents the late stages of a major merger. This suggests that while major mergers may not contribute significantly to the fueling of Seyfert-luminosity AGNs, interactions appear to play a more dominant role in the triggering and fueling of high-luminosity heavily obscured AGNs.
► We aimed to describe the effect of lignin S/G ratio of eucalyptus on wood saccharification. ► S/G ratio modify 3D cell wall structure and so cellulose availability to enzymatic attack. ► Cellulose, ...hemicelluloses and lignin formed a sheath protecting cellulose from the enzymatic attack. ► Ionic liquid were used to destroy 3D structure to improve cellulose availability.
There are several approaches being investigated to improve the efficiency of biomass conversion into fermentable sugars, including those that engineer the feedstocks to enhance digestibility. In this study it was evaluated the impact of genotype modifications of three mutants of Eucalyptus globulus L., and of the corresponding wild type on cellulose hydrolyzability before and after ionic liquid (IL) pretreatment. Both untreated and IL-treated samples were chemically characterized and tested for cellulose hydrolizability. Results obtained indicate that genetic modifications altered wood lignin-S/G ratio. This alteration resulted in a different hydrolyzability of cellulose for untreated samples, i.e. high lignin-S/G ratio produced low glucose yield (r=−0.97; P<0.03; n=4), but did not affect glucose yield after IL pretreatment. IL pretreated samples had increased glucose yields compared to that of untreated samples due to the modification of microcrystalline cellulose I to mixtures of more hydrolysable cellulose II and amorphous cellulose, and to the partial removal of the steric impediment, or removal of the lignin “sheath” protecting cellulose, to enzymes. The efficiency of the IL pretreatment used in this study does not appear to be affected by the S/G content of the E. globulus.
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