The phylogeny and evolutionary ecology of hoverflies (Diptera: Syrphidae) inferred from mitochondrial genomes.

Hoverflies (Diptera: Syrphidae) are a diverse group of pollinators and a major research focus in ecology, but their phylogenetic relationships remain incompletely known. Using a genome skimming approach we generated mitochondrial genomes for 91 species, capturing a wide taxonomic diversity of the family. To reduce the required amount of input DNA and overall cost of the library construction, sequencing and assembly was conducted on mixtures of specimens, which raises the problem of chimera formation of mitogenomes. We present a novel chimera detection test based on gene tree incongruence, but identified only a single mitogenome of chimeric origin. Together with existing data for a final set of 127 taxa, phylogenetic analysis on nucleotide and amino acid sequences using Maximum Likelihood and Bayesian Inference revealed a basal split of Microdontinae from all other syrphids. The remainder consists of several deep clades assigned to the subfamily Eristalinae in the current classification, including a clade comprising the subfamily Syrphinae (plus Pipizinae). These findings call for a re-definition of subfamilies, but basal nodes had insufficient support to fully justify such action. Molecular-clock dating placed the origin of the Syrphidae crown group in the mid-Cretaceous while the Eristalinae-Syrphinae clade likely originated near the K/Pg boundary. Transformation of larval life history characters on the tree suggests that Syrphidae initially had sap feeding larvae, which diversified greatly in diet and habitat association during the Eocene and Oligocene, coinciding with the diversification of angiosperms and the evolution of various insect groups used as larval host, prey, or mimicry models. Mitogenomes proved to be a powerful phylogenetic marker for studies of Syrphidae at subfamily and tribe levels, allowing dense taxon sampling that provided insight into the great ecological diversity and rapid evolution of larval life history traits of the hoverflies.

Antibodies to gp210 and understanding risk in patients with primary biliary cholangitis.

BACKGROUND AND AIMS: A variety of auto-antibody assays are available as part of the clinical care of patients with liver disease. We sought to better understand the clinical utility of immune serological testing in patients with primary biliary cholangitis (PBC). METHODS: We retrospectively analysed data from 2846 patients investigated for liver disease at a UK liver centre between 2001 and 2017. A total of 499 patients with PBC were identified. Immune serology results were examined for their diagnostic utility and prognostic significance to predict transplant-free survival. RESULTS: Antimitochondrial antibodies (AMAs) were specific (94.5%) and sensitive (85.6%) for PBC; antinuclear antibodies (ANAs) against glycoprotein 210 (gp210) and sp100 were specific (>98%) but not sensitive (<25%). The disease-specific ANAs were detectable in 29.6% of AMA-negative patients. Anti-gp210 auto-antibodies were significantly associated with elevated serum aminotransferase activity, bilirubin and liver stiffness at presentation (P < .010). Anti-gp210 auto-antibodies predicted non-response to ursodeoxycholic acid (UDCA) by GLOBE criteria (39.3% vs 16.7%, P = .005). Moreover, anti-gp210 was independently associated with death or liver transplantation (HR 3.22, 95% CI 1.49-6.96; P = .003), after accounting for other significant baseline determinants of outcome. Serologic finding of anti-gp210 antibodies conferred an independent risk of death or transplantation (HR 4.13, 95% CI 1.85-9.22; P = .001) after accounting for treatment response. CONCLUSION: In our single-centre cohort of patients with PBC, the presence of anti-gp210 was associated with an adverse presenting phenotype, predicted treatment non-response and independently predicted reduced transplant-free survival.

A validated workflow for rapid taxonomic assignment and monitoring of a national fauna of bees (Apiformes) using high throughput DNA barcoding.

Improved taxonomic methods are needed to quantify declining populations of insect pollinators. This study devises a high-throughput DNA barcoding protocol for a regional fauna (United Kingdom) of bees (Apiformes), consisting of reference library construction, a proof-of-concept monitoring scheme, and the deep barcoding of individuals to assess potential artefacts and organismal associations. A reference database of cytochrome oxidase c subunit 1 (cox1) sequences including 92.4% of 278 bee species known from the UK showed high congruence with morphological taxon concepts, but molecular species delimitations resulted in numerous split and (fewer) lumped entities within the Linnaean species. Double tagging permitted deep Illumina sequencing of 762 separate individuals of bees from a UK-wide survey. Extracting the target barcode from the amplicon mix required a new protocol employing read abundance and phylogenetic position, which revealed 180 molecular entities of Apiformes identifiable to species. An additional 72 entities were ascribed to nuclear pseudogenes based on patterns of read abundance and phylogenetic relatedness to the reference set. Clustering of reads revealed a range of secondary operational taxonomic units (OTUs) in almost all samples, resulting from traces of insect species caught in the same traps, organisms associated with the insects including a known mite parasite of bees, and the common detection of human DNA, besides evidence for low-level cross-contamination in pan traps and laboratory procedures. Custom scripts were generated to conduct critical steps of the bioinformatics protocol. The resources built here will greatly aid DNA-based monitoring to inform management and conservation policies for the protection of pollinators.

Agonist-induced membrane nanodomain clustering drives GLP-1 receptor responses in pancreatic beta cells.

The glucagon-like peptide-1 receptor (GLP-1R), a key pharmacological target in type 2 diabetes (T2D) and obesity, undergoes rapid endocytosis after stimulation by endogenous and therapeutic agonists. We have previously highlighted the relevance of this process in fine-tuning GLP-1R responses in pancreatic beta cells to control insulin secretion. In the present study, we demonstrate an important role for the translocation of active GLP-1Rs into liquid-ordered plasma membrane nanodomains, which act as hotspots for optimal coordination of intracellular signaling and clathrin-mediated endocytosis. This process is dynamically regulated by agonist binding through palmitoylation of the GLP-1R at its carboxyl-terminal tail. Biased GLP-1R agonists and small molecule allosteric modulation both influence GLP-1R palmitoylation, clustering, nanodomain signaling, and internalization. Downstream effects on insulin secretion from pancreatic beta cells indicate that these processes are relevant to GLP-1R physiological actions and might be therapeutically targetable.