Evolutionary History of Assassin Bugs (Insecta: Hemiptera: Reduviidae): Insights from Divergence Dating and Ancestral State Reconstruction

Assassin bugs are one of the most successful clades of predatory animals based on their species numbers (∼6,800 spp.) and wide distribution in terrestrial ecosystems. Various novel prey capture strategies and remarkable prey specializations contribute to their appeal as a model to study evolutionary pathways involved in predation. Here, we reconstruct the most comprehensive reduviid phylogeny (178 taxa, 18 subfamilies) to date based on molecular data (5 markers). This phylogeny tests current hypotheses on reduviid relationships emphasizing the polyphyletic Reduviinae and the blood-feeding, disease-vectoring Triatominae, and allows us, for the first time in assassin bugs, to reconstruct ancestral states of prey associations and microhabitats. Using a fossil-calibrated molecular tree, we estimated divergence times for key events in the evolutionary history of Reduviidae. Our results indicate that the polyphyletic Reduviinae fall into 11–14 separate clades. Triatominae are paraphyletic with respect to the reduviine genus Opisthacidius in the maximum likelihood analyses; this result is in contrast to prior hypotheses that found Triatominae to be monophyletic or polyphyletic and may be due to the more comprehensive taxon and character sampling in this study. The evolution of blood-feeding may thus have occurred once or twice independently among predatory assassin bugs. All prey specialists evolved from generalist ancestors, with multiple evolutionary origins of termite and ant specializations. A bark-associated life style on tree trunks is ancestral for most of the lineages of Higher Reduviidae; living on foliage has evolved at least six times independently. Reduviidae originated in the Middle Jurassic (178 Ma), but significant lineage diversification only began in the Late Cretaceous (97 Ma). The integration of molecular phylogenetics with fossil and life history data as presented in this paper provides insights into the evolutionary history of reduviids and clears the way for in-depth evolutionary hypothesis testing in one of the most speciose clades of predators.     

The Chimonanthus salicifolius genome provides insight into magnoliid evolution and flavonoid biosynthesis

Chimonanthus salicifolius, a member of the Calycanthaceae of magnoliids, is one of the most famous medicinal plants in Eastern China. Here, we report a chromosome‐level genome assembly of C. salicifolius, comprising 820.1 Mb of genomic sequence with a contig N50 of 2.3 Mb and containing 36 651 annotated protein‐coding genes. Phylogenetic analyses revealed that magnoliids were sister to the eudicots. Two rounds of ancient whole‐genome duplication were inferred in the C. salicifolious genome. One is shared by Calycanthaceae after its divergence with Lauraceae, and the other is in the ancestry of Magnoliales and Laurales. Notably, long genes with > 20 kb in length were much more prevalent in the magnoliid genomes compared with other angiosperms, which could be caused by the length expansion of introns inserted by transposon elements. Homologous genes within the flavonoid pathway for C. salicifolius were identified, and correlation of the gene expression and the contents of flavonoid metabolites revealed potential critical genes involved in flavonoids biosynthesis. This study not only provides an additional whole‐genome sequence from the magnoliids, but also opens the door to functional genomic research and molecular breeding of C. salicifolius.     

Intermediate Filaments from Bovine, Rat, and Human CNS: Mapping Analysis of the Major Proteins

Abstract: Intermediate filaments were isolated by an axon-flotation method from bovine, rat, and human CNS. Gel electrophoresis showed four major proteins, having molecular weights of about 50,000, 70,000, 160,000, and 210,000, to be present in filaments of all three species. Small differences in molecular weights and major differences in relative distribution of the filament proteins were observed among species. In bovine and rat brain the predominant protein was the 50,000 band, but in human brain the 70,000 band was present in greatest amount. Each filament protein of the three species was studied by peptide mapping using limited proteolysis and cyanogen bromide cleavage. Within the same molecular weight group, filament proteins from different species gave similar maps with both techniques. Some degree of heterogeneity was also observed. However, filament proteins of different molecular weights of the same species gave distinctly different maps. These studies rule out the possibility that filament proteins from different molecular weight groups are related to each other by oligomerization; nor is it likely that the lower molecular weight proteins are derived from the subunit of molecular weight 210,000.     

Utilization of ground eggshell waste as an adsorbent for the removal of dyes from aqueous solution

The adsorption of cationic basic blue 9 and anionic acid orange 51 from aqueous solution onto the calcified eggshell (ES) and its ground eggshell powder (ESP) was carried out by varying the process parameters such as agitation speed, initial dye concentration, adsorbent mass and temperature. The adsorption potential for basic blue 9 onto ESP is far lower than that for acid orange 51, mainly due to the ionic interaction between the acid dye with the sulfonate groups and the positively charged sites on the surface of ESP. The adsorption capacity of acid orange 51 onto ES is significantly smaller than that onto ESP, which is in line with their pore properties (i.e., 1 vs. 21 m(2)/g). The experimental results showed that the adsorption process can be well described with a simple model, the pseudo-second-order model. According to the equilibrium adsorption capacity from the fitting of pseudo-second order reaction model, it was further found that the Freundlich model yields a somewhat better fit than the Langmuir model in the adsorption of acid orange 51 onto ESP. In addition, an increase in adsorption temperature from 15 to 45 degrees C significantly enhances the adsorption capacity of acid orange 51 onto ESP, revealing that the adsorption should be an endothermic or chemisorption process. From the results, it is feasible to utilize the ground eggshell waste as an effective adsorbent for removal of anionic dye from aqueous solution.     

Biological implications of genetic variations in autism spectrum disorders from genomics studies

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental condition characterized by atypical social interaction and communication together with repetitive behaviors and restricted interests. The prevalence of ASD has been increased these years. Compelling evidence has shown that genetic factors contribute largely to the development of ASD. However, knowledge about its genetic etiology and pathogenesis is limited. Broad applications of genomics studies have revealed the importance of gene mutations at protein-coding regions as well as the interrupted non-coding regions in the development of ASD. In this review, we summarize the current evidence for the known molecular genetic basis and possible pathological mechanisms as well as the risk genes and loci of ASD. Functional studies for the underlying mechanisms are also implicated. The understanding of the genetics and genomics of ASD is important for the genetic diagnosis and intervention for this condition.