Multifunctional sequence-defined macromolecules for chemical data storage

Sequence-defined macromolecules consist of a defined chain length (single mass), end-groups, composition and topology and prove promising in application fields such as anti-counterfeiting, biological mimicking and data storage. Here we show the potential use of multifunctional sequence-defined macromolecules as a storage medium. As a proof-of-principle, we describe how short text fragments (human-readable data) and QR codes (machine-readable data) are encoded as a collection of oligomers and how the original data can be reconstructed. The amide-urethane containing oligomers are generated using an automated protecting-group free, two-step iterative protocol based on thiolactone chemistry. Tandem mass spectrometry techniques have been explored to provide detailed analysis of the oligomer sequences. We have developed the generic software tools Chemcoder for encoding/decoding binary data as a collection of multifunctional macromolecules and Chemreader for reconstructing oligomer sequences from mass spectra to automate the process of chemical writing and reading

Crystal structure of Porphyromonas gingivalis dipeptidyl peptidase 4 and structure-activity relationships based on inhibitor profiling

The Gram-negative anaerobe Porphyromonas gingivalis is associated with chronic periodontitis. Clinical isolates of P. gingivalis strains with high dipeptidyl peptidase 4 (DPP4) expression also had a high capacity for biofilm formation and were more infective. The X-ray crystal structure of P. gingivalis DPP4 was solved at 2.2 Å resolution. Despite a sequence identity of 32%, the overall structure of the dimer was conserved between P. gingivalis DPP4 and mammalian orthologues. The structures of the substrate binding sites were also conserved, except for the region called S2-extensive, which is exploited by specific human DPP4 inhibitors currently used as antidiabetic drugs. Screening of a collection of 450 compounds as inhibitors revealed a structure-activity relationship that mimics in part that of mammalian DPP9. The functional similarity between human and bacterial DPP4 was confirmed using 124 potential peptide substrates

Gastrointestinal Stromal Tumors

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Restorative Challenges and How to Overcome Them

© Springer International Publishing AG 2018. Restoration of deep carious lesions may be challenging in clinical practice. Many generations of dentists have been trained to remove all weakened carious dentin. This may, however, easily lead to pulp exposure and subsequent endodontic treatment. Especially this type of treatment may weaken a tooth, and it has been documented that endodontically treated teeth are more prone to fracture. New insights in the pathology of caries and the importance of a well-sealing restoration have led to changing treatment concepts. Selective carious tissue removal allows to avoid pulp exposure, but may also compromise the longevity of the restoration, mainly because of mechanical and adhesive reasons. Moreover, residual carious dentin is challenging with regard to radiographic diagnosis. In this chapter, these restorative challenges and possible solutions are discussed.status: publishe

Differential peptidomics highlights adipokinetic hormone as key player in regulating digestion in anautogenous flesh fly, Sarcophaga crassipalpis

Females of anautogenous flesh flies, Sarcophaga crassipalpis, need a protein meal in order to produce their first batch of eggs. This protein meal elicits an increase in midgut proteolytic activity that is under neuropeptidergic regulation. Time series of decapitation and rescue experiments of liver fed flies evidenced the need of a peptide factor released by corpora cardiaca (CC) within four hours post protein feeding in order to assure complete protein digestion. Q-Exactive quantitative differential peptidomics analysis on CC of sugar fed flies and flies five hours post protein feeding respectively, showed a unique consistent decrease in the stored amount of adipokinetic hormone (AKH) ranging between 16 up to 63%. Injection of AKH into liver fed decapitated flies as well as sugar fed intact flies resulted in dose dependent enhanced midgut proteolytic activity up to the level of intact protein fed flies. This suggests a key role of AKH in food depended reproductionpublisher: Elsevier articletitle: Differential peptidomics highlights adipokinetic hormone as key player in regulating digestion in anautogenous flesh fly, Sarcophaga crassipalpis journaltitle: General and Comparative Endocrinology articlelink: http://dx.doi.org/10.1016/j.ygcen.2014.08.016 content_type: article copyright: Copyright © 2014 Elsevier Inc. All rights reserved.status: publishe

Mass spectrometric profiling of (neuro)-peptides in the worker honeybee, Apis mellifera

The honeybee is the economically most important beneficial insect and a model for studying immunity, development and social behavior. Hence, this species was selected for genome sequencing and annotation. An intensive interplay between bioinformatics and mass spectrometry (MS) resulted in the annotation of 36 neuropeptide genes (Hummon et al., 2006). Exactly 100 peptides were demonstrated by a variety of MS techniques. In this follow-up study we dissected and analysed separately all ganglia of the central nervous system (CNS) of adult worker bees in three repeats. The combined MALDI-TOF spectra enabled the accurate mapping of 67 peptides, encoded by 20 precursors. We also demonstrated the expression of an additional but already predicted peptide. In addition to putative bioactive peptides we also list and discuss spacer peptides, propeptides and truncated peptides. The majority of such peptides have a more restricted distribution pattern. Their presence provides some information on the precursor turnover and/or the location of neural cell bodies in which they are produced. Of a given precursor, the (neuro)-peptides with the widest distribution pattern are likely to be the best candidates to interact with receptors. The separate analysis of a neuroendocrine complex and the mushroom body yields suggestions as to which (neuro)-peptides might act as hormones and which neuropeptides might be involved in the complex spectrum of non-hormone driven honeybee behaviour, at these sites. Our data complement immunohistochemical studies of (neuro)-peptides in the honeybee, and form a reference for comparative studies in other insect or arthropod models, in particular in the light of recent or upcoming genome projects. Finally, they also form a firm basis for physiological, functional and/or differential peptidomics studies in the honeybee.status: publishe

A comprehensive summary of LL-37, the factoctum human cathelicidin peptide

Cathelicidins are a group of antimicrobial peptides. Since their discovery, it has become clear that they are an exceptional class of peptides, with some members having pleiotropic effects. Not only do they possess an antibacterial, antifungal and antiviral function, they also show a chemotactic and immunostimulatory/-modulatory effect. Moreover, they are capable of inducing wound healing, angiogenesis and modulating apoptosis. Recent insights even indicate for a role of these peptides in cancer. This review provides a comprehensive summary of the most recent and relevant insights concerning the human cathelicidin LL-37.status: publishe

Sample size considerations for restoration-longevity randomized controlled trials

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Electrical Impedance Spectroscopy as a method for the label-free detection and characterization of novel bioactive peptides

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Detection and characterization of novel bioactive peptides using Electrical Impedance Spectroscopy

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