Thomas Vandendriessche

Nondestructive Measurement of Fruit and Vegetable Quality

We review nondestructive techniques for measuring internal and external quality attributes of fruit and vegetables, such as color, size and shape, flavor, texture, and absence of defects. The different techniques are organized according to their physical measurement principle. We first describe each technique and then list some examples. As many of these techniques rely on mathematical models and particular data processing methods, we discuss these where needed. We pay particular attention to techniques that can be implemented online in grading lines.

Purification, molecular cloning and functional characterization of HelaTx1 (Heterometrus laoticus): The first member of a new κ-KTX subfamily

Given their medical importance, most attention has been paid toward the venom composition of scorpions of the Buthidae family. Nevertheless, research has shown that the venom of scorpions of other families is also a remarkable source of unique peptidyl toxins. The κ-KTx family of voltage-gated potassium channel (VGPC) scorpion toxins is hereof an example. From the telson of the scorpion Heterometrus laoticus (Scorpionidae), a peptide, HelaTx1, with unique primary sequence was purified through HPLC and sequenced by Edman degradation. Based on the amino acid sequence, the peptide could be cloned and the cDNA sequence revealed. HelaTx1 was chemically synthesized and functionally characterized on VGPCs of the Shaker-related, Shab-related, Shaw-related and Shal-related subfamilies. Furthermore, the toxin was also tested on small- and intermediate conductance Ca(2+)-activated K(+) channels. From the channels studied, K(v)1.1 and K(v)1.6 were found to be the most sensitive (K(v)1.1 EC(50)=9.9±1.6 μM). The toxin did not alter the activation of the channels. Competition experiments with TEA showed that the toxin is a pore blocker. Mutational studies showed that the residues E353 and Y379 in the pore of K(v)1.1 act as major interaction points for binding of the toxin. Given the amino acid sequence, the predicted secondary structure and the biological activity on VGPCs, HelaTx1 should be included in the κ-KTX family. Based on a phylogenetic study, we rearranged this family of VGPC toxins into five subfamilies and suggest that HelaTx1 is the first member of the new κ-KTx5 subfamily.

Detection of Pseudomonas aeruginosa in sputum headspace through volatile organic compound analysis

IntroductionChronic pulmonary infection is the hallmark of Cystic Fibrosis lung disease. Searching for faster and easier screening may lead to faster diagnosis and treatment of Pseudomonas aeruginosa (P. aeruginosa). Our aim was to analyze and build a model to predict the presence of P. aeruginosa in sputa.MethodsSputa from 28 bronchiectatic patients were used for bacterial culturing and analysis of volatile compounds by gas chromatography–mass spectrometry. Data analysis and model building were done by Partial Least Squares Regression Discriminant analysis (PLS-DA). Two analysis were performed: one comparing P. aeruginosa positive with negative cultures at study visit (PA model) and one comparing chronic colonization according to the Leeds criteria with P. aeruginosa negative patients (PACC model).ResultsThe PA model prediction of P. aeruginosa presence was rather poor, with a high number of false positives and false negatives. On the other hand, the PACC model was stable and explained chronic P. aeruginosa presence for 95% with 4 PLS-DA factors, with a sensitivity of 100%, a positive predictive value of 86% and a negative predictive value of 100%.ConclusionOur study shows the potential for building a prediction model for the presence of chronic P. aeruginosa based on volatiles from sputum.

OdK2, a Kv1.3 channel-selective toxin from the venom of the Iranian scorpion Odonthobuthus doriae ☆

The first Kv1.3 channel-selective toxin from the venom of the Iranian scorpion Odonthobuthus doriae (OdK2) was purified, sequenced and characterized physiologically. OdK2 consists of 38 amino acids, including six conserved cysteine and a C-terminal lysine residue, as revealed by the unique use of a quadrupole ion cyclotron resonance Fourier-transform mass spectrometer. Based on multiple sequence alignments, OdK2 was classified as alpha-KTX3.11. The pharmacological effects of OdK2 were studied on a panel of eight different cloned K(+) channels (vertebrate Kv1.1-Kv1.6, Shaker IR and hERG) expressed in Xenopus laevis oocytes. Interestingly, OdK2 selectively inhibits the currents through Kv1.3 channels with an IC50 value of 7.2+/-2.7nM.

Evaluation of fast volatile analysis for detection of Botrytis cinerea infections in strawberry

Grey mold (Botrytis cinerea) is one of the major phytopathogens causing serious losses during strawberry postharvest and storage. B. cinerea-host interaction affect emissions of volatile compounds during infection resulting in a characteristic earthy, mushroom odor. Therefore, the objective of this study was to evaluate two analytical techniques based on fast volatile analysis on their performance for monitoring evolution and early detection of B. cinerea infections in strawberry. In a first experiment headspace multi-capillary column-ion mobility spectrometry (HS MCC-IMS) has been successfully used to evaluate development of strawberry aroma during shelflife. In a second experiment the same technique has been used to detect the degree of B. cinerea infection through changes in the volatile profile. Additionally, these samples were analyzed with headspace solid-phase-microextraction fast GC-MS (HS SPME fast GC-MS). Both HS MCC-IMS and HS SPME fast GC-MS could determine the changes in volatile composition as a function of the degree of B. cinerea infection as determined by an enzyme-linked immunosorbent assay (ELISA) and could be used to follow the evolution of infection. According to the ELISA data, some fruit were infected even without any symptoms and volatiles produced by the fungus may be overshadowed by the fruit volatiles. Therefore, both analytical techniques could not be used for early detection of B. cinerea infections. After identification of the volatile compounds and multivariate data analysis, potential biomarkers specific for B. cinerea were highlighted, being 3-methylbutanal, cis-4-decenal, 2-methyl-1-butanol, 2-methyl-1-propanol, 1-octen-3-one and 1-octen-3-ol.

Isolation and characterization of two novel scorpion toxins: The α-toxin-like CeII8, specific for Nav1.7 channels and the classical anti-mammalian CeII9, specific for Nav1.4 channels

Scorpion beta-toxins represent a particular pharmacological group of voltage-gated sodium channel (VGSC) neurotoxins. They typically shift the voltage dependence of activation to more hyperpolarizing potentials and reduce the peak current amplitude by binding to receptor-site 4. Here, we report the purification and functional characterization of the first voltage-gated sodium channel toxins, CeII8 and CeII9, isolated from the scorpion Centruroides elegans (Thorell, 1876), which is responsible for deadly cases of intoxication in Mexico. The soluble venom was fractionated by gel filtration and ion-exchange chromatography, followed by reversed-phase HPLC. The toxins CeII8 and CeII9 were further purified and both their amino acid sequence and molecular weight were determined. Both toxins were electrophysiologically characterized on four mammalian VGSCs (rNa(v)1.2, rNa(v)1.4, hNa(v)1.5 and rNa(v)1.7) expressed heterologously in Xenopus laevis oocytes, using the two-electrode voltage-clamp technique. Although CeII8 has the highest sequence similarity with scorpion alpha-toxins, inhibiting the inactivation of VGSCs, 300 nM toxin had a clear beta-toxin effect and was selective towards Na(v)1.7, involved in short-term and inflammatory pain. To the best of our knowledge, CeII8 is the first beta-toxin active on Na(v)1.7. CeII9, a typical anti-mammalian beta-toxin, selectively modulated Na(v)1.4 at a concentration of 700 nM and was, in contrast to CeII8, found to be lethal to mice. Interestingly, both toxins, despite their differences in amino acid sequence, only altered the biophysical properties of a fraction of the expressed sodium channels. Since these effects have also been reported for the beta-toxin CssIV, the bioactive surfaces of the toxins have been compared to each other.

Autogenous transalveolar transplantation of maxillary canines: a systematic review and meta-analysis

Summary Background and objectives The objective was to systematically review transalveolar transplantation of maxillary canines and the long-term outcome for an average follow-up period of 2 years or more. Data collection and analysis A systematic review of the currently available literature until December 2017 was conducted, using Medline, Cochrane Central, Web off Science, and PubMed. Articles were screened for 1. indications, 2. contra-indications, 3. surgical planning, 4. surgical technique, 5. associated risk factors, and 6. long-term outcome for transalveolar transplantation of maxillary canines with the following outcome measures: bone-related outcomes, tooth-related outcomes, soft tissue-related outcomes, and aesthetic outcome measures. Descriptive statistics, as well as a quality assessment of included articles, were performed. Following study retrieval and selection, relevant data was extracted and the risk of bias was assessed using the Methodological index for non-randomized studies (MINORS). Results Twelve articles were included in this review. These studies included outcome data for 783 autotransplanted maxillary canines, with long-term studies indicating a clinically acceptable overall outcome. Limitations Since the lack of randomized controlled trials considering this topic, the quality of the evidence in the present review is considered low. However, impacted maxillary canines are a rare anomaly and different aspects, such as position of the impacted canine, patient’s age and patient’s demands, and expectancies must be taken into account, it is practically impossible to randomize treatment. Conclusions There is sufficient evidence to justify the transalveolar transplantation of maxillary canines as a legitimate treatment technique for impacted maxillary canines deemed difficult to treat with surgical exposure and subsequent orthodontic alignment. Long-term studies have shown that a good overall outcome is to be expected. There is no clear agreement in the literature on the indications and contra-indications for transalveolar transplantation of maxillary canines. Implication of key findings It is highly desirable that further research on this issue be undertaken, high-quality observational studies are recommended. Registration PROSPERO (CRD42017056348)

2BIC: taking your adventuring gear to organise pop‐up health information literacy sessions

Academic libraries play an important role in the provision of health information literacy (IL) skills and there are many approaches to how these can be delivered. In this paper, guest writers Inge Discart and colleagues from KU Leuven Libraries 2Bergen Information Centre (2BIC) in Belgium discuss a pop-up information literacy skills project. In particular, the article presents the findings from an initial information skills needs assessment conducted at the University, followed by how the concept of the pop-up sessions was developed and promoted throughout the organisation. The paper identifies the variety of sessions offered and the format in which they were delivered, with final results on how these were received and which sessions were the most popular. This article provides insight into an alternative approach to health information skills delivery and the outcomes from it. H S.