Nesting ecology and cuticular microbial loads in dampwood (Zootermopsis angusticollis) and drywood termites (Incisitermes minor, I. schwarzi, Cryptotermes cavifrons)

Termites form one-piece nests in wood that can vary in their moisture content and degree of decomposition, and thus microbial richness. To estimate the microbial load of nests and the potential risk they pose for colony members, we quantified the number of microbes in the nest and on the cuticle of the dampwood termite, Zootermopsis angusticollis, and three drywood termites, Incisitermes minor, I. schwarzi, and Cryptotermes cavifrons. The number of colony forming units (CFUs) cultured from nest material samples and washes of the cuticle of larvae and nymphs were determined. CFUs recorded from nest material was low (fewer than 60 CFUs/g) in the drywood termites and comparatively high in the dampwood species, as more than 800 bacterial and fungal CFUs/g were cultured from the nest material of Z. angusticollis. Similarly, cuticular microbial loads were negligible in the drywood termites sampled, ranging from 0.5 to fewer than 16 CFUs/cm(2), whereas approximately 200 CFUs/cm(2) were cultured from Z. angusticollis. The nesting and feeding habits of these basal species likely influence colony microbial load and the degree of pathogen exposure, which in turn could favor adaptations to resist disease that vary with termite nesting biology. Abbreviation: / CFU: colony forming uni

Blastic plasmacytoid dendritic cell neoplasm : State of the art and prospects

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare tumour, which usually a_ects elderly males and presents in the skin with frequent involvement of the bone-marrow, peripheral blood and lymph nodes. It has a dismal prognosis, with most patients dying within one year when treated by conventional chemotherapies. The diagnosis is challenging, since neoplastic cells can resemble lymphoblasts or small immunoblasts, and require the use of a large panel of antibodies, including those against CD4, CD56, CD123, CD303, TCL1, and TCF4. The morphologic and in part phenotypic ambiguity explains the uncertainties as to the histogenesis of the neoplasm that led to the use of various denominations. Recently, a series of molecular studies based on karyotyping, gene expression profiling, and next generation sequencing, have largely unveiled the pathobiology of the tumour and proposed the potentially beneficial use of new drugs. The latter include SL-401, anti-CD123 immunotherapies, venetoclax, BET-inhibitors, and demethylating agents. The epidemiologic, clinical, diagnostic, molecular, and therapeutic features of BPDCN are thoroughly revised in order to contribute to an up-to-date approach to this tumour that has remained an orphan disease for too long

An enzymatic flow-based preparative route to vidarabine

The bi-enzymatic synthesis of the antiviral drug vidarabine (arabinosyladenine, ara-A), catalyzed by uridine phosphorylase from Clostridium perfringens (CpUP) and a purine nucleoside phosphorylase fromAeromonas hydrophila (AhPNP), was re-designed under continuous-flow conditions. Glyoxyl-agarose and EziGTM1 (Opal) were used as immobilization carriers for carrying out this preparative biotransformation. Upon setting-up reaction parameters (substrate concentration and molar ratio, temperature, pressure, residence time), 1 g of vidarabine was obtained in 55% isolated yield and >99% purity by simply running the flow reactor for 1 week and then collecting (by filtration) the nucleoside precipitated out of the exiting flow. Taking into account the substrate specificity of CpUP and AhPNP, the results obtained pave the way to the use of the CpUP/AhPNP-based bioreactor for the preparation of other purine nucleosides

Batch and Flow Synthesis of Nucleosides by Enzymatic Transglycosylation

Enzymatic methods for the preparation of high-value products have clearly shown their potential in many areas, including nucleic acid chemistry. Enzymes of nucleic acid metabolism such as nucleoside phosphorylases (NPs, EC 2.4.2) can be conveniently used as biocatalysts in the synthesis of nucleoside analogues. These enzymes catalyze the reversible cleavage of the glycosidic bond of (deoxy)ribonucleosides in the presence of inorganic phosphate (Pi) to generate the nucleobase and \u3b1-D-(deoxy)ribose-1-phosphate (phosphorolysis). If a second nucleobase is added to the reaction medium, the formation of a new nucleoside can result (transglycosylation). Because of its broad substrate specificity [1,2], a purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) was exploited to catalyze the \u201cone-pot, one-enzyme\u201d transglycosylation of 7-methylguanosine iodide with a series of 6-substituted purines, resulting in a moderate to high conversion (18-65%) of the bases into a 22-compound library of 6-substituted purine ribonucleosides [2]. Successively, AhPNP was covalently immobilized [3,4] in a pre-packed column containing aminopropyl silica particles. The resulting AhPNP-IMER (Immobilized Enzyme Reactor) was coupled on-line to a HPLC apparatus containing a semi-preparative chromatographic column. In such a system, \u201cone-enzyme\u201d transglycosylation and product purification were run in a single platform, affording a set of 6-modified purine ribonucleosides at a mg scale [4]. Using this \u201cflow-based\u201d approach, the synthesis of adenine nucleosides through a \u201ctwo-enzyme\u201d transglycosylation was carried out by connecting the AhPNP-IMER to uridine phosphorylase from Clostridium perfringens, immobilized on a silica monolithic column (CpUP-IMER)

Surface Plasmon Resonance as a Tool for Ligand Binding Investigation of Engineered GPR17 Receptor, a G Protein Coupled Receptor Involved in Myelination

The aim of this study was to investigate the potential of surface plasmon resonance (SPR) spectroscopy for the measurement of real-time ligand-binding affinities and kinetic parameters for GPR17, a G protein-coupled receptor (GPCR) of major interest in medicinal chemistry as potential target in demyelinating diseases. The receptor was directly captured, in a single-step, from solubilized membrane extracts on the sensor chip through a covalently bound anti-6x-His-antibody and retained its ligand binding activity for over 24h. Furthermore, our experimental setup made possible, after a mild regeneration step, to remove the bound receptor without damaging the antibody, and thus to reuse many times the same chip. Two engineered variants of GPR17, designed for crystallographic studies, were expressed in insect cells, extracted from crude membranes and analyzed for their binding with two high affinity ligands: the antagonist Cangrelor and the agonist Asinex 1. The calculated kinetic parameters and binding constants of ligands were in good agreement with those reported from activity assays and highlighted a possible functional role of the N-terminal residues of the receptor in ligand recognition and binding. Validation of SPR results was obtained by docking and molecular dynamics of GPR17-ligands interactions and by functional in vitro studies. The latter allowed us to confirm that Asinex 1 behaves as GPR17 receptor agonist, inhibits forskolin-stimulated adenylyl cyclase pathway and promotes oligodendrocyte precursor cell maturation and myelinating ability

The Effect of Soundscapes and Lightscapes on the Perception of Safety and Social Presence Analyzed in a Laboratory Experiment

The present study evaluates the effect of soundscape and lightscape variations on the perceived safety and perceived social presence in a pedestrian area through laboratory experiments. Thirty-one participants were presented with nine different virtual scenarios, in which the same underpass was reproduced under different soundscape and lightscape conditions. The participants were asked to assess each scenario considering 10 items related to perceived safety and perceived social presence. A principal component analysis allowed the 10 items to be reduced to two principal components, namely “perceived safety” and “perceived social presence”. A two-way repeated measures ANOVA analysis was conducted to assess the effect of modifications of both the soundscape and lightscape on the two components. The obtained results showed that the soundscape had an effect on both the perceived safety (p < 0.05) and perceived social presence (p < 0.05), while the lightscape variations implemented in this experiment only had a statistically significant effect on the latter (p < 0.05). The results of such studies may be of interest for public design and management as they may be conducted by means of non-intrusive and cost-effective techniques

PO-272 Leukemia-associated NPM mutations promote quiescence of hematopoietic stem cells and prevent their functional exhaustion upon oncogene-induced hyper-proliferation

Introduction Acute Myeloid Leukaemia (AML) is a heterogeneous and multi-step disease. The serial acquisition of mutations and the environmental pressure allow one or more clones to expand and contribute to the disease. In particular, 6% of AMLs are characterised by an initial mutation in the DNMT3a gene, followed by mutations in NPM (NPMc) and FLT3 loci (FLT3-ITD). We previously shown that NPMc can drive AML development in mouse model and highly cooperates with FLT3-ITD. Moreover, it has been reported that normal Hematopoietic Stem Cells (HSCs) of elderly people may bear some somatic early AML mutations and this correlate with an increased risk of hematologic diseases suggesting that mutations can shape pre-leukemic HSCs to be more prone to the acquisition of further mutations giving rise to Leukaemia Initiating Cells (LIC). While the ability of FLT3-ITD to drive HSC compartment exhaustion has been already shown, the impact of NPMc on HSCs remains unclear. Material and methods Taking advantage of the extended pre-leukemic phase of our inducible NPMc mouse model, we elucidate the role of NPMc in HSCs by functional and transcriptional analysis. Moreover, to investigate the basis of NPMc and FLT3-ITD cooperation we generate mice carrying both the conditional NPMc transgene and the FLT3-ITD constitutive mutation and, before AML onset, we analyse double mutant HSCs behaviour. Results and discussions We have found that NPMc expression lead to the expansion of the HSC compartment through the enforcement of a stem-cell transcriptional program that increases self-renewal by promoting quiescence. We then investigated how the NPMc dependent quiescence program is linked to its oncogenic function. The expression of NPMc +in the FLT3-ITD background prevents the HSCs exhaustion imposed by FLT3-ITD and restores their repopulating capacity. Accordingly, gene expression analysis revealed a strong dominance of NPMc +with the restoration of the same transcriptional program observed in the NPMc HSCs. These data strongly suggest that NPMc imposes a HSC-specific program that, in combination with the oncogenic signal provided by FLT3-ITD, allows the selection of the LIC and the occurrence of AML. Conclusion In conclusion, enforcement of quiescence might be a critical function for the maintenance of the transformed clone during both the pre-leukemic and the leukemic phase. As consequence, interfering with quiescence key determinants may eradicate the reservoir of quiescent cells responsible for disease recurrence

Malaria chemoprophylaxis recommendations for immigrants to Europe, visiting relatives and friends - a Delphi method study

BACKGROUND: Numbers of travellers visiting friends and relatives (VFRs) from Europe to malaria endemic countries are increasing and include long-term and second generation immigrants, who represent the major burden of malaria cases imported back into Europe. Most recommendations for malaria chemoprophylaxis lack a solid evidence base, and often fail to address the cultural, social and economic needs of VFRs. METHODS: European travel medicine experts, who are members of TropNetEurop, completed a sequential series of questionnaires according to the Delphi method. This technique aims at evaluating and developing a consensus through repeated iterations of questionnaires. The questionnaires in this study included questions about professional experience with VFRs, controversial issues in malaria prophylaxis, and 16 scenarios exploring indications for prescribing and choice of chemoprophylaxis. RESULTS: The experience of participants was rather diverse as was their selection of chemoprophylaxis regimen. A significant consensus was observed in only seven of 16 scenarios. The analysis revealed a wide variation in prescribing choices with preferences grouped by region of practice and increased prescribing seen in Northern Europe compared to Central Europe. CONCLUSIONS: Improving the evidence base on efficacy, adherence to chemoprophylaxis and risk of malaria and encouraging discussion among experts, using techniques such as the Delphi method, may reduce the variability in prescription in European travel clinics