Legume abundance along successional and rainfall gradients in Neotropical forests

The nutrient demands of regrowing tropical forests are partly satisfied by nitrogen-fixing legume trees, but our understanding of the abundance of those species is biased towards wet tropical regions. Here we show how the abundance of Leguminosae is affected by both recovery from disturbance and large-scale rainfall gradients through a synthesis of forest inventory plots from a network of 42 Neotropical forest chronosequences. During the first three decades of natural forest regeneration, legume basal area is twice as high in dry compared with wet secondary forests. The tremendous ecological success of legumes in recently disturbed, water-limited forests is likely to be related to both their reduced leaflet size and ability to fix N2, which together enhance legume drought tolerance and water-use efficiency. Earth system models should incorporate these large-scale successional and climatic patterns of legume dominance to provide more accurate estimates of the maximum potential for natural nitrogen fixation across tropical forests.Additional co-authors: Rebecca J. Cole, Gabriel Dalla Colletta, Ben de Jong, Julie S. Denslow, Saara J. DeWalt, Juan Manuel Dupuy, Sandra M. Durán, Mário Marcos do Espírito Santo, G. Wilson Fernandes, Yule Roberta Ferreira Nunes, Bryan Finegan, Vanessa Granda Moser, Jefferson S. Hall, José Luis Hernández-Stefanoni, André B. Junqueira, Deborah Kennard, Edwin Lebrija-Trejos, Susan G. Letcher, Madelon Lohbeck, Erika Marín-Spiotta, Miguel Martínez-Ramos, Jorge A. Meave, Duncan N. L. Menge, Francisco Mora, Rodrigo Muñoz, Robert Muscarella, Susana Ochoa-Gaona, Edith Orihuela-Belmonte, Rebecca Ostertag, Marielos Peña-Claros, Eduardo A. Pérez-García, Daniel Piotto, Peter B. Reich, Casandra Reyes-García, Jorge Rodríguez-Velázquez, I. Eunice Romero-Pérez, Lucía Sanaphre-Villanueva, Arturo Sanchez-Azofeifa, Naomi B. Schwartz, Arlete Silva de Almeida, Jarcilene S. Almeida-Cortez, Whendee Silver, Vanessa de Souza Moreno, Benjamin W. Sullivan, Nathan G. Swenson, Maria Uriarte, Michiel van Breugel, Hans van der Wal, Maria das Dores Magalhães Veloso, Hans F. M. Vester, Ima Célia Guimarães Vieira, Jess K. Zimmerman & Jennifer S. Power

A tale of worldwide success: Behind the scenes of Carex (Cyperaceae) biogeography and diversification

The megadiverse genus Carex (c. 2000 species, Cyperaceae) has a nearly cosmopolitan distribution, displaying an inverted latitudinal richness gradient with higher species diversity in cold-temperate areas of the Northern Hemisphere. Despite great expansion in our knowledge of the phylogenetic history of the genus and many molecular studies focusing on the biogeography of particular groups during the last few decades, a global analysis of Carex biogeography and diversification is still lacking. For this purpose, we built the hitherto most comprehensive Carex-dated phylogeny based on three markers (ETS–ITS–matK), using a previous phylogenomic Hyb-Seq framework, and a sampling of two-thirds of its species and all recognized sections. Ancestral area reconstruction, biogeographic stochastic mapping, and diversification rate analyses were conducted to elucidate macroevolutionary biogeographic and diversification patterns. Our results reveal that Carex originated in the late Eocene in E Asia, where it probably remained until the synchronous diversification of its main subgeneric lineages during the late Oligocene. E Asia is supported as the cradle of Carex diversification, as well as a “museum” of extant species diversity. Subsequent “out-of-Asia” colonization patterns feature multiple asymmetric dispersals clustered toward present times among the Northern Hemisphere regions, with major regions acting both as source and sink (especially Asia and North America), as well as several independent colonization events of the Southern Hemisphere. We detected 13 notable diversification rate shifts during the last 10 My, including remarkable radiations in North America and New Zealand, which occurred concurrently with the late Neogene global cooling, which suggests that diversification involved the colonization of new areas and expansion into novel areas of niche space.This work was carried out with financial support by the National Science Foundation (Award #1255901 to ALH and Award #1256033 to EHR), the Spanish Ministry of Economy and Competitiveness (project CGL2016–77401‐P to SM-B and ML), the USDA National Institute of Food and Agriculture (McIntire Stennis project 1018692 to DS) as well as postdoctoral fellowships towards SM‐B (Universidad Pablo de Olavide, PP16/12‐APP), and PJ‐M (National Science Foundation, Award #1256033, and the Smithsonian Postdoctoral Fellowship program)

Presbyopia:Effectiveness of correction strategies

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states “presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements”. Presbyopia is inevitable if one lives long enough, but intrinsic and extrinsic risk factors including cigarette smoking, pregnancy history, hyperopic or astigmatic refractive error, ultraviolet radiation, female sex (although accommodation is similar to males), hotter climates and some medical conditions such as diabetes can accelerate the onset of presbyopic symptoms. Whilst clinicians can ameliorate the symptoms of presbyopia with near vision spectacle correction, bifocal and progressive spectacle lenses, monovision, translating or multifocal contact lenses, monovision, extended depth of focus, multifocal (refractive, diffractive and asymmetric designs) or ‘accommodating’ intraocular lenses, corneal inlays, scleral expansion, laser refractive surgery (corneal monovision, corneal shrinkage, corneal multifocal profiles and lenticular softening), pharmacologic agents, and electro-stimulation of the ciliary muscle, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is gives on presbyopic correction evaluation techniques

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Duration of interphenophases in winegrapes

Shifts in phenological events due to climate change have been widely studied. Yet, few studies have looked at interphenophases, the duration between two phenological events, and how they have been affected by climate change. This gap presents an opportunity to better understand both fundamental plant development and how climate change could impact it. Using hierarchical Bayesian modeling and a diverse dataset of winegrape varieties collected at Domaine de Vassal in the south of France, we determine how phenological events and interphenophases have changed since 1980. Overall event date advanced for budburst, flowering, veraison, and maturity as temperatures increased. Despite these advances, we found that most interphenophases lengthened: across all varieties budburst to flowering, veraison to maturity, and budburst to maturity lengthened while flowering to veraison remained the same. Among ripening classifications, we found no difference in change over time for budburst to flowering, veraison to maturity, or budburst to maturity, but found that for flowering to veraison, change in days per decade increased as ripening occurred later in the season. When looking at the growing degree days (GDD) of interphenophases, GDD increased for all phenological events and interphenophases. These results suggest that winegrape development may be limited by factors other than temperature, such as sugar accumulation during ripening. Moreover, we found high diversity in interphenophase rates of change among variety. While the diversity of winegrape varieties represents an important resource as vineyards prepare for changing climates, more work needs to be done to understand what characteristics are driving variety differences. Additionally, our GDD shifts indicate a need to revise GDD calculations to reflect how grapevines experience high temperatures.Forestry, Faculty ofGraduat

GENOMIC IDENTITY OF WHITE OAK SPECIES IN AN EASTERN NORTH AMERICAN SYNGAMEON

Hipp AL, Whittemore AT, Garner M, et al. GENOMIC IDENTITY OF WHITE OAK SPECIES IN AN EASTERN NORTH AMERICAN SYNGAMEON. ANNALS OF THE MISSOURI BOTANICAL GARDEN. 2019;104(3):455-477.The eastern North American white oaks, a complex of approximately 16 potentially interbreeding species, have become a classic model for studying the genetic nature of species in a syngameon. Genetic work over the past two decades has demonstrated the reality of oak species, but gene flow between sympatric oaks raises the question of whether there are conserved regions of the genome that define oak species. Does gene flow homogenize the entire genome? Do the regions of the genome that distinguish a species in one part of its range differ from the regions that distinguish it in other parts of its range, where it grows in sympatry with different species? Or are there regions of the genome that are relatively conserved across species ranges? In this study, we revisit seven species of the eastern North American white oak syngameon using a set of 80 single-nucleotide polymorphisms (SNPs) selected in a previous study because they show differences among, and consistency within, the species. We test the hypothesis that there exist segments of the genome that do not become homogenized by repeated introgression, but retain distinct alleles characteristic of each species. We undertake a range-wide sampling to investigate whether SNPs that appeared to be fixed based on a relatively small sample in our previous work are fixed or nearly fixed across the range of the species. Each of the seven species remains genetically distinct across its range, given our diagnostic set of markers, with relatively few individuals exhibiting admixture of multiple species. SNPs map back to all 12 Quercus linkage groups (chromosomes) and are separated from each other by an average of 7.47 million bp ((+) 8.74 million bp, SD), but are significantly clustered relative to a random null distribution, suggesting that our SNP toolkit reflects genome-wide patterns of divergence while potentially being concentrated in regions of the genome that reflect a higher-than-average history of among-species divergence. This application of a DNA toolkit designed for the simple problem of identifying species in the field has two important implications. First, the eastern North American white oak syngameon is composed of entities that most taxonomists would consider "good species." Second, and more fundamentally, species in the syngameon are genetically coherent because characteristic portions of the genome remain divergent despite a history of introgression. Understanding the conditions under which some loci diverge while others introgress is key to understanding the origins and maintenance of global tree diversity

Oxidative stress and abnormal lipid profile are common factors in students with eating distress

Numerous studies on complications associated with eating disorders have been conducted worldwide. However such studies are limited in the Indian scenario. Hence, we attempted to analyse the presence of oxidative stress along with total lipid profiling of students with eating distress in Mysore, South India. A biochemical test panel was conducted using serum samples of controls and subjects. Results were statistically analyzed using SPSS software version 14. Analysis of variance was used to identify significant differences between study groups. Variations in all parameters confirmed the occurrence of oxidative stress and abnormal lipid contents in students prone to eating disorders