Evolution of nectar spur length in a clade of Linaria reflects changes in cell division rather than in cell expansion.

BACKGROUND AND AIMS: Nectar spurs (tubular outgrowths of a floral organ which contain, or give the appearance of containing, nectar) are hypothesized to be a 'key innovation' which can lead to rapid speciation within a lineage, because they are involved in pollinator specificity. Despite the ecological importance of nectar spurs, relatively little is known about their development. We used a comparative approach to investigate variation in nectar spur length in a clade of eight Iberian toadflaxes. METHODS: Spur growth was measured at the macroscopic level over time in all eight species, and growth rate and growth duration compared. Evolution of growth rate was reconstructed across the phylogeny. Within the clade we then focused on Linaria becerrae and Linaria clementei, a pair of sister species which have extremely long and short spurs, respectively. Characterization at a micromorphological level was performed across a range of key developmental stages to determine whether the difference in spur length is due to differential cell expansion or cell division. KEY RESULTS: We detected a significant difference in the evolved growth rates, while developmental timing of both the initiation and the end of spur growth remained similar. Cell number is three times higher in the long spurred L. becerrae compared with L. clementei, whereas cell length is only 1.3 times greater. In addition, overall anisotropy of mature cells is not significantly different between the two species. CONCLUSIONS: We found that changes in cell number and therefore in cell division largely explain evolution of spur length. This contrasts with previous studies in Aquilegia which have found that variation in nectar spur length is due to directed cell expansion (anisotropy) over variable time frames. Our study adds to knowledge about nectar spur development in a comparative context and indicates that different systems may have evolved nectar spurs using disparate mechanisms

The evo-devo of plant speciation

Speciation research bridges the realms of macro- and microevolution. Evolutionary developmental biology (evo-devo) has classically dealt with macroevolutionary questions through a comparative approach to distantly related organisms, but the field later broadened in focus to address recent speciation and microevolution. Here we review available evidence of the power of evo-devo approaches to understand speciation in plants at multiple scales. At a macroevolutionary scale, evidence is accumulating for evolutionary developmental mechanisms giving rise to key innovations promoting speciation. At the macro microevolution transition, we review instances of evo-devo change underlying both the origin of reproductive barriers and phenotypic changes distinguishing closely related species. At the microevolutionary scale, the study of developmental variation within species provides insight into the processes that generate the raw material for evolution and speciation. We conclude by advocating a strong interaction between developmental biology and evolutionary biology at multiple scales to gain a deeper understanding of plant speciation.M.F.-M. has been supported by the Marie Curie Intra-European Fellowship LINARIA-SPECIATION (FP7-PEOPLE-2013-IEF, project reference 624396 to M.F.-M and B.J.G) and an Isaac Newton Trust Research Grant (Trinity College, Cambridge)

A synopsis of the Iberian clade of Linaria subsect. Versicolores (Antirrhineae, Plantaginaceae) based on integrative taxonomy

Integrative taxonomy, based on the combination of multiple lines of evidence, provides the foundations for a robust species delimitation. Here we provide a taxonomic synopsis of the Iberian clade of Linaria subsect. Versicolores based on recently published morphometric and phylogenomic data. This clade radiated in the Iberian Peninsula (western Mediterranean)during the Quaternary, and is being intensively studied from phylogenetic, evolutionary, biogeographic, ecological and developmental standpoints. Eight morphologically and genetically distinct species are recognized in the clade: L. algarviana, L. becerrae, L. clementei, L. incarnata, L. onubensis, L. salzmannii, L. spartea and L. viscosa. For each accepted species, the type material and notes on diagnostic characters, distribution, habitat and intraspecific variability are provided. Five names are typified (four neotypes and one lectotype are designated), and references to previous typifications are also presented. A distribution map and an identification key are presented. This synopsis will provide the basis for future research on speciation and evolution of the clade

Treatment with sotrovimab for SARS-CoV-2 infection in a cohort of high-risk kidney transplant recipients

COVID-19; Immunosuppression; Kidney transplantationCOVID-19; Inmunosupresión; Trasplante de riñónCOVID-19; Immunosupressió; Trasplantament de ronyóBackground Sotrovimab is a neutralizing monoclonal antibody (mAb) that seems to remain active against recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. The evidence on its use in kidney transplant (KT) recipients, however, is limited. Methods We performed a multicenter, retrospective cohort study of 82 KT patients with SARS-CoV-2 infection {coronavirus disease 2019 [COVID-19]} treated with sotrovimab. Results Median age was 63 years. Diabetes was present in 43.9% of patients, and obesity in 32.9% of patients; 48.8% of patients had an estimated glomerular filtration rate under 30 mL/minute/1.73 m2. Additional anti–COVID-19 therapies were administered to 56 patients, especially intravenous steroids (65.9%). Sotrovimab was administered early (<5 days from the onset of the symptoms) in 46 patients (56%). Early-treated patients showed less likely progression to severe COVID-19 than those treated later, represented as a lower need for ventilator support (2.2% vs 36.1%; P < .001) or intensive care admission (2.2% vs 25%; P = .002) and COVID-19–related mortality (2.2% vs 16.7%; P = .020). In the multivariable analysis, controlling for baseline risk factors to severe COVID-19 in KT recipients, early use of sotrovimab remained as a protective factor for a composite outcome, including need for ventilator support, intensive care, and COVID-19–related mortality. No anaphylactic reactions, acute rejection episodes, impaired kidney function events, or non-kidney side effects related to sotrovimab were observed. Conclusions Sotrovimab had an excellent safety profile, even in high-comorbidity patients and advanced chronic kidney disease stages. Earlier administration could prevent progression to severe disease, while clinical outcomes were poor in patients treated later. Larger controlled studies enrolling KT recipients are warranted to elucidate the true efficacy of monoclonal antibody therapies.The Spanish COVID-19 renal registry and the Transplant Working Group of the Spanish Society of Nephrology (SENTRA) are supported by the Spanish Society of Nephrology

How have advances in comparative floral development influenced our understanding of floral evolution?

Evolutionary developmental biology has come to prominence in the past two decades, in both the plant kingdom and the animal kingdom, particularly following the description of homeotic genes linked to key morphological transitions. A primary goal of evolutionary developmental biology (“evo-devo”) is to define how developmental programs are modified to generate novel or labile morphologies. This requires an understanding of the molecular genetic basis of these programs and of the evolutionary changes they have undergone. The past decade has seen the establishment of a common language and common standards, and these changes have greatly improved the integration of evo-devo. Recently, a more comparative approach has been added to mechanistic developmental biology. In this review we attempt to show how, by using this “next-generation evo-devo” approach, insights into both developmental biology and evolutionary biology can be gained. Although the concepts we discuss are more broadly applicable, we have focused our examples on traits of the angiosperm flower, a structure that has undergone enormous morphological and developmental evolution since its relatively recent appearance in the fossil record.Work in the Glover laboratory on these topics is funded by the BBSRC, EU Marie Curie Actions, Isaac Newton Trust, Leverhulme Trust, NERC and the NSF, and we gratefully acknowledge all support.This is the accepted manuscript of a paper published in the International Journal of Plant Sciences (Glover BJ, Airoldi CA, Brockington SF, Fernández-Mazuecos M, Martínez-Pérez C, Mellers G, Moyroud E, Taylor L, International Journal of Plant Sciences, 2015, 176, 4, 307-323, doi:10.1086/681562). The final version is available at http://dx.doi.org/10.1086/68156

The genomic basis of the plant island syndrome in Darwin’s giant daisies

The repeated, rapid and often pronounced patterns of evolutionary divergence observed in insular plants, or the ‘plant island syndrome’, include changes in leaf phenotypes, growth, as well as the acquisition of a perennial lifestyle. Here, we sequence and describe the genome of the critically endangered, Galápagos-endemic species Scalesia atractyloides Arnot., obtaining a chromosome-resolved, 3.2-Gbp assembly containing 43,093 candidate gene models. Using a combination of fossil transposable elements, k-mer spectra analyses and orthologue assignment, we identify the two ancestral genomes, and date their divergence and the polyploidization event, concluding that the ancestor of all extant Scalesia species was an allotetraploid. There are a comparable number of genes and transposable elements across the two subgenomes, and while their synteny has been mostly conserved, we find multiple inversions that may have facilitated adaptation. We identify clear signatures of selection across genes associated with vascular development, growth, adaptation to salinity and flowering time, thus finding compelling evidence for a genomic basis of the island syndrome in one of Darwin’s giant daisies

Historical Isolation versus Recent Long-Distance Connections between Europe and Africa in Bifid Toadflaxes (Linaria sect. Versicolores)

Background: Due to its complex, dynamic and well-known paleogeography, the Mediterranean region provides an ideal framework to study the colonization history of plant lineages. The genus Linaria has its diversity centre in the Mediterranean region, both in Europe and Africa. The last land connection between both continental plates occurred during the Messinian Salinity Crisis, in the late Miocene (5.96 to 5.33 Ma). Methodology/Principal Findings: We analyzed the colonization history of Linaria sect. Versicolores (bifid toadflaxes), which includes c. 22 species distributed across the Mediterranean, including Europe and Africa. Two cpDNA regions (rpl32-trnL UAG and trnK-matK) were sequenced from 66 samples of Linaria. We conducted phylogenetic, dating, biogeographic and phylogeographic analyses to reconstruct colonization patterns in space and time. Four major clades were found: two of them exclusively contain Iberian samples, while the other two include northern African samples together with some European samples. The bifid toadflaxes have been split in African and European clades since the late Miocene, and most lineage and speciation differentiation occurred during the Pliocene and Quaternary. We have strongly inferred four events of post-Messinian colonization following long-distance dispersal from northern Africa to the Iberian Peninsula, Sicily and Greece. Conclusions/Significance: The current distribution of Linaria sect. Versicolores lineages is explained by both ancien

Diffuse ST segment depression from hypothermia

Hypothermia is known to cause specific electrocardiographic (EKG) changes such as Osborne waves and bradycardia. We report diffuse ST segment depression, an atypical EKG change, in a patient with a core temperature of 29.4°C (85°F). This patient had no previous cardiovascular pathology, and his EKG changes resolved gradually with aggressive warming. We also discuss the pathophysiology and clinical significance of ST depression in the general population and the typical EKG changes in hypothermia patients

Export and turnover of transparent exopolymer particles into the deep ocean

2nd Meeting of the Iberian Ecological Society (SIBECOL), XXI conference of the Iberian Association of Limnology (AIL) and 21st National Congress of the Portuguese Ecological Society (SPECO), 3-8 July 2022, AveiroAcidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs play a key role in the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. Yet, very little is known about TEP distribution, export, and turnover at a global scale, particularly at deep ocean depths. We provide the first inventory of TEP from the surface up to 4000 m depth in the Atlantic, Indian, and Pacific Oceans and have assessed their contribution to carbon export into the deep ocean. Primary production determines TEP concentration above the deep chlorophyll maximum, and prokaryotic biomass also contributes in deeper waters. In the deep ocean waters, TEP concentrations are lower and mirror the concentrations in the surface, evidencing the importance of TEP sinking both at the export depth (200 m) with a global value of 2.9 Pg C year-1 and at the sequestration depth (1000 m) of 0.9 Pg C year-1 of particulate carbon. However, incubation experiments across ocean basins depicted rapid TEP turnover rates of 71 and 333 days (on average) within the export and sequestration depths, respectively. These findings reveal that the export of carbon by TEP sinking towards deep oceans escapes from long-term paths of the global carbon cycleN