The colonization of land by plants shaped the terrestrial biosphere, the geosphere and global climates. The nature of morphological and molecular innovation driving land plant evolution has been an ...enigma for over 200 years. Recent phylogenetic and palaeobotanical advances jointly demonstrate that land plants evolved from freshwater algae and pinpoint key morphological innovations in plant evolution. In the haploid gametophyte phase of the plant life cycle, these include the innovation of mulitcellular forms with apical growth and multiple growth axes. In the diploid phase of the life cycle, multicellular axial sporophytes were an early innovation priming subsequent diversification of indeterminate branched forms with leaves and roots. Reverse and forward genetic approaches in newly emerging model systems are starting to identify the genetic basis of such innovations. The data place plant evo-devo research at the cusp of discovering the developmental and genetic changes driving the radiation of land plant body plans.
This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.
The morphology of plant fossils from the Rhynie chert has generated longstanding questions about vascular plant shoot and leaf evolution, for instance, which morphologies were ancestral within land ...plants, when did vascular plants first arise and did leaves have multiple evolutionary origins? Recent advances combining insights from molecular phylogeny, palaeobotany and evo–devo research address these questions and suggest the sequence of morphological innovation during vascular plant shoot and leaf evolution. The evidence pinpoints testable developmental and genetic hypotheses relating to the origin of branching and indeterminate shoot architectures prior to the evolution of leaves, and demonstrates underestimation of polyphyly in the evolution of leaves from branching forms in ‘telome theory’ hypotheses of leaf evolution. This review discusses fossil, developmental and genetic evidence relating to the evolution of vascular plant shoots and leaves in a phylogenetic framework.
This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.
We present integral field unit observations covering the O iiiλλ4959, 5007 and Hβ emission lines of 16 z < 0.2 type 2 active galactic nuclei (AGN). Our targets are selected from a well-constrained ...parent sample of ≈24 000 AGN so that we can place our observations into the context of the overall AGN population. Our targets are radio quiet with star formation rates (SFRs; ≲10–100 M⊙ yr−1) that are consistent with normal star-forming galaxies. We decouple the kinematics of galaxy dynamics and mergers from outflows. We find high-velocity ionized gas (velocity widths ≈600–1500 km s−1; maximum velocities ≤1700 km s−1) with observed spatial extents of ≳(6–16) kpc in all targets and observe signatures of spherical outflows and bi-polar superbubbles. We show that our targets are representative of z < 0.2, luminous (i.e. LO iii > 1041.7 erg s−1) type 2 AGN and that ionized outflows are not only common but also in ≥70 per cent (3σ confidence) of cases, they are extended over kiloparsec scales. Our study demonstrates that galaxy-wide energetic outflows are not confined to the most extreme star-forming galaxies or radio-luminous AGN; however, there may be a higher incidence of the most extreme outflow velocities in quasars hosted in ultraluminous infrared galaxies. Both star formation and AGN activity appear to be energetically viable to drive the outflows and we find no definitive evidence that favours one process over the other. Although highly uncertain, we derive mass outflow rates (typically ≈10 times the SFRs), kinetic energies (≈0.5–10 per cent of L
AGN) and momentum rates (typically ≳10–20 × L
AGN/c) consistent with theoretical models that predict AGN-driven outflows play a significant role in shaping the evolution of galaxies.
Clathrin is a molecular scaffold for vesicular uptake of cargo at the plasma membrane, where its assembly into cage-like lattices underlies the clathrin-coated pits of classical endocytosis. This ...review describes the structures of clathrin, major cargo adaptors, and other proteins that participate in forming a clathrin-coated pit, loading its contents, pinching off the membrane as a lattice-enclosed vesicle, and recycling the components. It integrates as much of the structural information as possible at the time of writing into a sketch of the principal steps in coated-pit and coated-vesicle formation.
Using a sample of 24 264 optically selected active galactic nuclei (AGNs) from the SDSS DR7 data base, we characterize how the profile of the O iii λ5007 emission line relates to bolometric ...luminosity (L
AGN), Eddington ratio, radio loudness, radio luminosity (L
1.4 GHz) and optical class (i.e. broad/narrow-line Seyfert 1, type 2) to determine what drives the kinematics of this kpc-scale line emitting gas. First, we use spectral stacking to characterize how the average O iii λ5007 profile changes as a function of these five variables. After accounting for the known correlation between L
AGN and L
1.4 GHz, we report that L
1.4 GHz has the strongest influence on the O iii λ5007 profile, with AGNs of moderate radio luminosity (L
1.4 GHz = 1023-1025 W Hz−1) having the broadest O iii λ5007 profiles. Conversely, we find only a modest change in the O iii λ5007 profile with increasing radio loudness and find no significant difference between the O iii λ5007 profiles of broad- and narrow-line Seyfert 1s. When binned according to Eddington ratio, only the AGNs in our highest bin (i.e. >0.3) show any signs of having broadened O iii λ5007 profiles, although the small numbers of such extreme AGNs in our sample mean we cannot rule out that other processes (e.g. radio jets) are responsible for this broadening. The O iii λ5007 profiles of type 1 and type 2 AGNs show the same trends in terms of line width, but type 1 AGNs display a much stronger 'blue wing', which we interpret as evidence of outflowing ionized gas. We perform multicomponent fitting to the Hβ, O iii λλ4959, 5007, N ii λλ6548, 6584 and Hα lines for all the AGNs in our sample to calculate the proportions of AGNs with broad O iii λ5007 profiles. The individual fits confirm the results from our stacked spectra; AGNs with L
1.4 GHz > 1023 W Hz−1 are roughly five times more likely to have extremely broad O iii λ5007 lines (full width at half-maximum, FWHMAvg > 1000 km s−1) compared to lower L
1.4 GHz AGNs, and the width of the O iii λ5007 line peaks in moderate-radio-luminosity AGNs (L
1.4 GHz ∼ 1024 W Hz−1). Our results are consistent with the most disturbed gas kinematics being induced by compact radio cores (rather than powerful radio jets), although broadened O iii λ5007 lines are also present, but much rarer, in low-L
1.4 GHz systems. Our catalogue of multicomponent fits is freely available as an online resource for statistical studies of the kinematics and luminosities of the narrow- and broad-line AGN regions and the identification of potential targets for follow-up observations at http://sites.google.com/site/sdssalpaka.
In this study, we investigate the relationship between the star formation rate (SFR) and AGN luminosity (
$\mathrel {L_{\rm AGN}}$
) for ∼2000 X-ray detected AGN. The AGN span over three orders of ...magnitude in X-ray luminosity (
$10^{42} <\, \mathrel {L_{2{\rm -}8\,\mathrm{keV}}}\,< 10^{45.5} \mathrel {\,\rm erg \; s^{-1}}$
) and are in the redshift range z = 0.2–2.5. Using infrared (IR) photometry (8–500
$\mathrel {\,\rm \mu m}$
), including deblended Spitzer and Herschel images and taking into account photometric upper limits, we decompose the IR spectral energy distributions into AGN and star formation components. Using the IR luminosities due to star formation, we investigate the average SFRs as a function of redshift and AGN luminosity. In agreement with previous studies, we find a strong evolution of the average SFR with redshift, tracking the observed evolution of the overall star-forming galaxy population. However, we find that the relationship between the average SFR and AGN luminosity is broadly flat at all redshifts and across all the AGN luminosities investigated; in comparison to previous studies, we find less scatter amongst the average SFRs across the wide range of AGN luminosities investigated. By comparing to empirical models, we argue that the observed flat relationship is due to short time-scale variations in AGN luminosity, driven by changes in the mass accretion rate, which wash out any underlying correlations between SFR and
$\mathrel {L_{\rm AGN}}$
. Furthermore, we show that the exact form of the predicted relationship between SFR and AGN luminosity (and its normalization) is highly sensitive to the assumed intrinsic Eddington ratio distribution.
The authors show that the diverse mutations in
CALR
that occur in nonmutated
JAK2
myeloproliferative diseases all introduce frameshift mutations that alter the C-terminal part of the protein and ...affect its distribution within cells.
The myeloproliferative neoplasms are chronic myeloid cancers that are characterized by the overproduction of mature blood cells, and that may evolve into acute myeloid leukemia.
1
,
2
In addition to chronic myeloid leukemia with the
BCR-ABL
fusion gene, the three most common myeloproliferative neoplasms are essential thrombocythemia, polycythemia vera, and myelofibrosis.
Many patients with a
BCR-ABL–
negative myeloproliferative neoplasm carry a Janus kinase 2 (
JAK2
) V617F mutation.
3
–
6
The
JAK2
V617F mutation or
JAK2
exon 12 mutations are found in most patients with polycythemia vera,
7
,
8
whereas the
JAK2
V617F mutation is found in only 50 to 60% of . . .
The origin of land plants was accompanied by new adaptations to life on land, including the evolution of stomata—pores on the surface of plants that regulate gas exchange. The genes that underpin the ...development and function of stomata have been extensively studied in model angiosperms, such as Arabidopsis. However, little is known about stomata in bryophytes, and their evolutionary origins and ancestral function remain poorly understood. Here, we resolve the position of bryophytes in the land plant tree and investigate the evolutionary origins of genes that specify stomatal development and function. Our analyses recover bryophyte monophyly and demonstrate that the guard cell toolkit is more ancient than has been appreciated previously. We show that a range of core guard cell genes, including SPCH/MUTE, SMF, and FAMA, map back to the common ancestor of embryophytes or even earlier. These analyses suggest that the first embryophytes possessed stomata that were more sophisticated than previously envisioned and that the stomata of bryophytes have undergone reductive evolution, including their complete loss from liverworts.
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•Land plants comprise two sister lineages, bryophytes and tracheophytes•Their common ancestor possessed complex stomata•Stomata were lost or reduced during the evolution of bryophytes•Liverwort air pores evolved following stomatal loss in the liverwort ancestor
Harris et al. provide phylogenomic support for the monophyly of bryophytes and show that many of the genes that pattern and operate stomata in modern tracheophytes, such as Arabidopsis, were already present in the common ancestor of land plants. The analyses indicate that the simple stomata of modern bryophytes are a result of reductive evolution.
Abstract
STUDY QUESTION
What are appraisals, coping strategies and emotional reactions of patients to coronavirus disease 2019 (COVID-19) fertility clinic closures?
SUMMARY ANSWER
Clinic closure was ...appraised as stressful due to uncertainty and threat to the attainability of the parenthood goal but patients were able to cope using strategies that fit the uncertainty of the situation.
WHAT IS KNOWN ALREADY
Psychological research on COVID-19 suggests that people are more anxious than historical norms and moderately to extremely upset about fertility treatment cancellation owing to COVID-19.
STUDY DESIGN, SIZE, DURATION
The study was of cross-sectional design, comprising a mixed-methods, English language, anonymous, online survey posted from April 9 to 21 to social media. Eligibility criteria were being affected by COVID-19 fertility clinic closure, 18 years of age or older and able to complete the survey in English. In total, 946 people clicked on the survey link, 76 did not consent, 420 started but did not complete the survey and 450 completed (48% completion, 446 women, four men).
PARTICIPANTS/MATERIALS, SETTING, METHODS
Overall 74.7% (n = 336) of respondents were residents in the UK with an average age of 33.6 years (SD = 4.4) and average years trying to conceive, 3.5 years (SD = 2.22). The survey comprised quantitative questions about the intensity of cognitive appraisals and emotions about clinic closure, and ability to cope with clinic closure. Open-text questions covered their understanding of COVID-19 and its effect on reproductive health and fertility plans, concerns and perceived benefits of clinic closure, and knowledge about closure. Sociodemographic information was collected. Descriptive and inferential statistics were used on quantitative data. Thematic qualitative analysis (inductive coding) was performed on the textual data from each question. Deductive coding grouped themes from each question into meta-themes related to cognitive stress and coping theory.
MAIN RESULTS AND THE ROLE OF CHANCE
Most patients (81.6%, n = 367) had tests or treatments postponed, with these being self (41.3%, n = 186) or publicly (46.4%, n = 209) funded. Patients appraised fertility clinic closure as having potential for a more negative than positive impact on their lives, and to be very or extremely uncontrollable and stressful (P ≤ 0.001). Most reported a slight to moderate ability to cope with closure. Data saturation was achieved with all open-text questions, with 33 broad themes identified and four meta-themes linked to components of the cognitive stress and coping theory. First, participants understood clinic closure was precautionary due to unknown effects of COVID-19 but some felt clinic closure was unfair relative to advice about getting pregnant given to the public. Second, closure was appraised as a threat to attainability of the parenthood goal largely due to uncertainty of the situation (e.g. re-opening, effect of delay) and intensification of pre-existing hardships of fertility problems (e.g. long time waiting for treatment, history of failed treatment). Third, closure taxed personal coping resources but most were able to cope using thought-management (e.g. distraction, focusing on positives), getting mentally and physically fit for next treatments, strengthening their social network, and keeping up-to-date. Finally, participants reported more negative than positive emotions (P ≤ 0.001) and, almost all participants reported stress, worry and frustration at the situation, while some expressed anger and resentment at the unfairness of the situation. Overall, 11.8% were not at all able to cope, with reports of intense feelings of hopelessness and deteriorating well-being and mental health.
LIMITATIONS, REASONS FOR CAUTION
The survey captures patient reactions at a specific point in time, during lockdown and before clinics announced re-opening. Participants were self-selected (e.g. UK residents, women, 48% starting but not completing the survey), which may affect generalisability.
WIDER IMPLICATIONS OF THE FINDINGS
Fertility stakeholders (e.g. clinics, patient support groups, regulators, professional societies) need to work together to address the great uncertainty from COVID-19. This goal can be met proactively by setting up transparent processes for COVID-19 eventualities and signposting to information and coping resources. Future psychological research priorities should be on identifying patients at risk of distress with standardised measures and developing digital technologies appropriate for the realities of fertility care under COVID-19.
STUDY FUNDING/COMPETING INTEREST(S)
University funded research. Outside of the submitted work, Prof. J.B. reports personal fees from Merck KGaA, Merck AB, Theramex, Ferring Pharmaceuticals A/S; grants from Merck Serono Ltd; and that she is co-developer of the Fertility Quality of Life (FertiQoL) and MediEmo apps. Outside of the submitted work, Dr R.M. reports personal or consultancy fees from Manchester Fertility, Gedeon Richter, Ferring and Merck. Outside of the submitted work, Dr S.G. reports consultancy fees from Ferring Pharmaceuticals A/S, Access Fertility and SONA-Pharm LLC, and grants from Merck Serono Ltd. The other authors declare no conflicts of interest.
TRIAL REGISTRATION NUMBER
N/A.
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