Genome sequence of the Asian Tiger mosquito, Aedes albopictus, reveals insights into its biology, genetics, and evolution

The Asian tiger mosquito, Aedes albopictus, is a highly successful invasive species that transmits a number of human viral diseases, including dengue and Chikungunya fevers. This species has a large genome with significant population-based size variation. The complete genome sequence was determined for the Foshan strain, an established laboratory colony derived from wild mosquitoes from southeastern China, a region within the historical range of the origin of the species. The genome comprises 1,967 Mb, the largest mosquito genome sequenced to date, and its size results principally from an abundance of repetitive DNA classes. In addition, expansions of the numbers of members in gene families involved in insecticide-resistance mechanisms, diapause, sex determination, immunity, and olfaction also contribute to the larger size. Portions of integrated flavivirus-like genomes support a shared evolutionary history of association of these viruses with their vector. The large genome repertory may contribute to the adaptability and success of Ae. albopictus as an invasive species.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

Site-specific structural characterization of O-glycosylation and identification of phosphorylation sites of recombinant osteopontin

Osteopontin (OPN) plays a key role in multiple physiological and pathological processes such as cytokine production, mineralization, inflammation, immune responses, and tumorigenesis. Post-translational modifications (PTMs) of OPN significantly affect its structure and biological properties; however, site-specific characterization of O-glycosylation in human OPN has not been reported. In this work, we profiled the overall glycan pattern of human recombinant OPN using a lectin array and completed detailed structural analysis of O-glycopeptides by mass spectrometry (MS). We detected 28 O-glycopeptides from 7 O-glycosylation regions of human OPN, occupied by highly heterogeneous O-glycans. These O-glycans carried, in part, functionally relevant epitopes such as T antigens (Galβ1-3GalNAcα1-), sialyl-Tn antigens, sialyl-T antigens, and sialyl-Le(x/a) antigens [Neuα2-3Galβ1-4(Fucα1-3)GlcNAc/Neuα2-3Galβ1-3(Fucα1-4)GlcNAc]. MS(3) spectra of the generated O-glycopeptides showed cleavages of the peptide backbone and provided essential information on the peptide sequence. Furthermore, 26 phosphorylation sites were identified by reverse-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS), including a novel one (Y209). We provide a detailed, site-specific structural characterization of O-glycosylation and identify the phosphorylation sites of OPN. These data lay the foundation for further research into the role of oligosaccharides and phosphorylation of recombinant human OPN. This article is part of a Special Issue entitled: Medical Proteomics.

Two-step protease digestion and glycopeptide capture approach for accurate glycosite identification and glycoprotein sequence coverage improvement

A novel two-step protease digestion and glycopeptide capture approach has been developed. It is different from traditional tryptic digestion, glycopeptide enriching and identification approach in glycoproteomics. Here, proteins were first digested by Lys-C into relatively large peptides. Glycopeptides among them were selectively captured by hydrazide resin through oxidized glycans. After thorough washing steps, trypsin was used as a second protease to in situ release non-glycosylated part (named as LT-peptides) from glycopeptides. Subsequently, the remaining part of glycopeptides on resin was de-glycosylated by peptide-N-glycosidase F, and collected as DG-peptides. Finally, both LT- and DG-peptides could be analyzed by mass spectrometer, achieving glycoprotein and glycosite identification. The approach was applied to cell lysate after positive validation by a model glycoprotein: 143 N-glycoproteins identified from DG- and LT-fraction both. In those glycoproteins, 189 DG-peptide-revealed N-glycosites got further confirmation by neighboring LT-peptides, which, in the meantime, made 109 glycoproteins get improved sequence coverage with increase even up to 350% (averagely 79.4%). Through controllable release, separate identification and combined interpretation of non-glycopeptides (newly introduced LT-peptides here) and traditional de-glycopeptides, the approach could not only achieve routine N-glycosite identification, but also provide further proofs of N-glycosites and increase glycoprotein sequence coverage.