Phylogenomics and biogeography of the small carpenter bees (Apidae: Xylocopinae: Ceratina).

Small carpenter bees in the genus Ceratina are behaviourally diverse, species-rich, and cosmopolitan, with over 370 species and a range including all continents except Antarctica. Here, we present the first comprehensive phylogeny of the genus based on ultraconserved element (UCE) phylogenomic data, covering a total of 185 ingroup specimens representing 22 of the 25 current subgenera. Our results support most recognized subgenera as natural groups, but we also highlight several groups in need of taxonomic revision - particularly the nominate subgenus Ceratina sensu stricto - and several clades that likely need to be described as new subgenera. In addition to phylogeny, we explore the evolutionary history of Ceratina through divergence time estimation and biogeographic reconstruction. Our findings suggest that Ceratinini split from its sister tribe Allodapini about 72 million years ago. The common ancestor of Ceratina emerged in the Afrotropical realm approximately 42 million years ago, near the Middle Eocene Climatic Optimum. Multiple subsequent dispersal events led to the present cosmopolitan distribution of Ceratina, with the majority of transitions occurring between the Afrotropics, Indomalaya, and the Palearctic. Additional movements also led to the arrival of Ceratina in Madagascar, Australasia, and a single colonization of the Americas. Dispersal events were asymmetrical overall, with temperate regions primarily acting as destinations for migrations from tropical source regions.

Evolutionary Origins and Patterns of Diversification in Animal Brood Parasitism.

AbstractBrood parasitism involves the exploitation of host parental care rather than the extraction of resources directly from hosts. We identify defining characteristics of this strategy and consider its position along continua with adjacent behaviors but focus on canonical brood parasites, where parasitism is obligate and hosts are noneusocial (thereby distinguishing from social parasitism). A systematic literature survey revealed 59 independently derived brood parasitic lineages with most origins (49) in insects, particularly among bees and wasps, and other origins in birds (seven) and fish (three). Insects account for more than 98% of brood parasitic species, with much of that diversity reflecting ancient (≥100-million-year-old) brood parasitic lineages. Brood parasites usually, but not always, evolve from forms that show parental care. In insects, brood parasitism often first evolves through exploitation of a closely related species, following Emery's rule, but this is less typical in birds, which we discuss. We conducted lineage-level comparisons between brood parasitic clades and their sister groups, finding mixed results but an overall neutral to negative effect of brood parasitism on species richness and diversification. Our review of brood parasites reveals many unanswered questions requiring new research, including further modeling of the coevolutionary dynamics of brood parasites and their hosts.

Genome of the bee Holcopasites calliopsidis-a species showing the common apid trait of brood parasitism.

Brood parasites represent a substantial but often poorly studied fraction of the wider diversity of bees. Brood parasitic bees complete their life cycles by infiltrating the nests of solitary host bees thereby enabling their offspring to exploit the food provisions intended for the host's offspring. Here, we present the draft assembly of the bee Holcopasites calliopsidis, the first brood parasitic species to be the subject of detailed genomic analysis. Consistent with previous findings on the genomic signatures of parasitism more broadly, we find that H. calliopsidis has the smallest genome currently known among bees (179 Mb). This small genome does not appear to be the result of purging of repetitive DNA, with some indications of novel repetitive elements which may show signs of recent expansion. Nor does H. calliopsidis demonstrate any apparent net loss of genic content in comparison with nonparasitic species, though many individual gene families do show significant contractions. Although the basis of the small genome size of this species remains unclear, the identification of over 12,000 putative genes-with functional annotation for nearly 10,000 of these-is an important step in investigating the genomic basis of brood parasitism and provides a valuable dataset to be compared against new genomes that remain to be sequenced.

Phylogenetic relationships and the evolution of host preferences in the largest clade of brood parasitic bees (Apidae: Nomadinae).

Brood parasites (also known as cleptoparasites) represent a substantial fraction of global bee diversity. Rather than constructing their own nests, these species instead invade those of host bees to lay their eggs. Larvae then hatch and consume the food provisions intended for the host's offspring. While this life history strategy has evolved numerous times across the phylogeny of bees, the oldest and most speciose parasitic clade is the subfamily Nomadinae (Apidae). However, the phylogenetic relationships among brood parasitic apids both within and outside the Nomadinae have not been fully resolved. Here, we present new findings on the phylogeny of this diverse group of brood parasites based on ultraconserved element (UCE) sequence data and extensive taxon sampling with 114 nomadine species representing all tribes. We suggest a broader definition of the subfamily Nomadinae to describe a clade that includes almost all parasitic members of the family Apidae. The tribe Melectini forms the sister group to all other Nomadinae, while the remainder of the subfamily is composed of two sister clades: a "nomadine line" representing the former Nomadinae sensu stricto, and an "ericrocidine line" that unites several mostly Neotropical lineages. We find the tribe Osirini Handlirsch to be polyphyletic, and divide it into three lineages, including the newly described Parepeolini trib. nov. In addition to our taxonomic findings, we use our phylogeny to explore the evolution of different modes of parasitism, detecting two independent transitions from closed-cell to open-cell parasitism. Finally, we examine how nomadine host-parasite associations have evolved over time. In support of Emery's rule, which suggests close relationships between hosts and parasites, we confirm that the earliest nomadines were parasites of their close free-living relatives within the family Apidae, but that over time their host range broadened to include more distantly related hosts spanning the diversity of bees. This expanded breadth of host taxa may also be associated with the transition to open-cell parasitism.

Refractory asthma: mechanisms, targets, and therapy.

Asthma is a common medical condition affecting 300 million people worldwide. Airway inflammation, smooth muscle bronchoconstriction leading to airflow obstruction, and mucous hypersecretion are clinical hallmarks of asthma. The NHLBI Expert Panel Report 3 recommends inhaled corticosteroids (ICS) for patients with moderate to severe persistent asthma. Inhaled corticosteroids (ICS) target gene transcription through their interactions with the glucocorticoid (GC) receptor (GR) at the glucocorticoid response element (GRE). The GC/GR complex enhances anti-inflammatory but inhibits pro-inflammatory mediator production. Classically, asthma has been described as a Th2-associated eosinophil-predominant disease, but recently alternative models have been described including a Th17-mediated neutrophil-predominant phenotype resulting in patients with more severe disease who may be less responsive to steroids. Additional mechanisms of steroid resistance include increased activity of GR phosphorylating kinases which modify the interactions of GR with transcription factors to inhibit the ability of GR to bind with GRE, leading to an increase in pro-inflammatory gene transcription. Oxidative stress also affects the balance between pro-inflammatory and anti-inflammatory gene transcription through the modification of transcription factors and cofactors (such as PI3K) leading to the inhibition of histone deacetylase 2. Continued investigations into the mechanisms behind glucocorticoid resistance will lead to novel treatments that improve control of severe refractory asthma.

Surface mass spectrometry of molecular species.

This tutorial discusses the predominant methods available for surface mass spectrometry (MS) of molecular species: thermal desorption spectroscopy, laser desorption MS, secondary ion MS, post-ionization of desorbed neutrals and surface matrix-assisted laser desorption/ionization. Each of these has the capability to analyze molecular species that are chemisorbed, physisorbed, covalently bound to or the predominant component of a solid surface. These surface MS methods are briefly described, then their capabilities demonstrated using data predominantly from the authors' work. Comparisons are made with related methods in conventional MS. A very brief discussion is provided on the importance of complementing surface MS data with data from x-ray photoelectron spectroscopy and other surface analysis tools.

Surface mass spectrometry of biotinylated self-assembled monolayers.

Biotin and biotinylated self-assembled monolayers (SAMs) on gold have been investigated using time-of-flight secondary ion mass spectrometry, direct laser desorption, laser desorption with 193 nm photoionization of ion- and laser-desorbed species, and laser desorption with vacuum ultraviolet (VUV, 118 nm) photoionization. Our results indicate that direct laser desorption and laser desorption combined with 193 nm multiphoton ionization can detect a chromophoric molecule like biotin that is covalently bound to a SAM. However, secondary ion mass spectra were dominated by fragmentation, and ion desorption/193 nm photoionization detected no species related to biotin. The dominant features of the laser desorption/VUV mass spectra were neat and Au-complexed dimers of intact and fragmented biotinylated SAM molecules. Multiphoton and single-photon ionization of laser-desorbed neutrals from biotinylated SAMs both led to the production of ions useful for chemical analysis of the monolayer. Multiphoton ionization with ultraviolet radiation was experimentally less challenging but required a chromophore for ionization and resulted in significant fragmentation of the adsorbate. Single-photon ionization with VUV radiation was experimentally more challenging but did not require a chromophore and led to less fragmentation. X-ray photoelectron spectra indicated that the biotinylated SAM formed a disordered, 40-60 Å thick monolayer on Au. Additionally, projection photolithography with a Schwarzschild microscope was used to pattern the biotinylated SAM surface and laser desorption/photoionization was used to detect biotinylated adsorbates from the ∼10 µm sized pattern.