A comparative study of supports for the synthesis of oligonucleotides without using ammonia

A comparative study of the cleavage efficiency of succinyl, phthaloyl, oxalyl, 2(2-nitrophenyl)ethyl, 9-fluorenylmethyl, and 2-nitrobenzyl supports in 0.5M DBU solutions is described. A decrease in cleavage efficiency is observed when small oligonucleotides containing thymidine are linked to the supports. In these conditions oxalyl supports gave the best yields followed by 2-(2-nitrophenyl)ethyl and 9-fluorenylmethyl supports.We are grateful to CICYT (PB92-0043) and E.E.C.C. Biomedicine and Health Programme (BMH1-CT93-1669) for financial support. We thank Drs. Matthias Mann, Gitte Neubauer, Matthias Wilm (EMBL) and Irene Fernández (University of Barcelona) for obtaining mass spectra.Peer reviewe

Alginate Hydrogels as Scaffolds and Delivery Systems to Repair the Damaged Spinal Cord

Alginate (ALG) is a lineal hydrophilic polysaccharide present in brown algae cell walls, which turns into a gel state when hydrated. Gelation readily produces a series of three dimensional (3D) architectures like fibers, capillaries, and microspheres, used as biosensors and bio‐actuators in a plethora of biomedical applications like drug delivery and wound healing. Hydrogels have made a great impact on regenerative medicine and tissue engineering because they are able to mimic the mechanical properties of natural tissues due to their high water content. Recent advances in neurosciences have led to promising strategies for repairing and/or regenerating the damaged nervous system. Spinal cord injury (SCI) is particularly challenging, owing to its devastating medical, human, and social consequences. Although effective therapies to repair the damaged spinal cord (SC) are still lacking, multiple pharmacological, genetic, and cell‐based therapies are currently under study. In this framework, ALG hydrogels constitute a source of potential tools for the development of implants capable of promoting axonal growth and/or delivering cells or drugs at specific damaged sites, which may result in therapeutic strategies for SCI. In this mini‐review, the current state of the art of ALG applications in neural tissues for repairing the damaged spinal cord is discussed

Label-free electrochemical DNA sensor using "click"-functionalized PEDOT electrodes

Here we describe a label-free electrochemical DNA sensor based on poly(3,4-ethylenedioxythiophene)-modified (PEDOT-modified) electrodes. An acetylene-terminated DNA probe, complementary to a specific "Hepatitis C" virus sequence, was immobilized onto azido-derivatized conducting PEDOT electrodes using "click" chemistry. DNA hybridization was then detected by differential pulse voltammetry, evaluating the changes in the electrochemical properties of the polymer produced by the recognition event. A limit of detection of 0.13. nM was achieved using this highly selective PEDOT-based genosensor, without the need for labeling techniques or microelectrode fabrication processes. These results are promising for the development of label-free and reagentless DNA hybridization sensors based on conducting polymeric substrates. Biosensors can be easily prepared using any DNA sequence containing an alkyne moiety. The data presented here reveal the potential of this DNA sensor for diagnostic applications in the screening of diseases, such as "Hepatitis C", and genetic mutations.The authors would like to thank the ICTS “NANBIOSIS”, more specifically to the Nanotechnology Platform, unit of the Networking Biomedical Research Center in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN) at the Institute for Bioengineering of Catalonia (IBEC) and also to the Serveis Cientificotècnics (SCT) of the Universitat de Barcelona (UB) for their assistance in XPS and ToF-SIMS analyses. This work was supported by Networking Biomedical Research Center in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN), Spain. The Nanobioengineering group at IBEC receives support from the Spanish Ministry of Science and Education and the Commission for Universities and Research of the Department of Innovation, Universities and Enterprise of the Generalitat de Catalunya (No. 2009 SGR 505). In addition, the research received support from the Spanish Ministry of Science and Education, CICYT (CTQ2009-07758), and the Fundación Botín, Santander, Spain.Peer reviewe

The Effect of Small Cosolutes that Mimic Molecular Crowding Conditions on the Stability of Triplexes Involving Duplex DNA

Triplex stability is studied in crowding conditions using small cosolutes (ethanol, acetonitrile and dimethylsulfoxide) by ultraviolet (UV), circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopies. The results indicate that the triplex is formed preferentially when the triplex forming oligonucleotide (TFO) is RNA. In addition, DNA triplexes (D:D\ub7D) are clearly less stable in cosolute solutions while the stability of the RNA triplexes (R:D\ub7D) is only slightly decreased. The kinetic of triplex formation with RNA-TFO is slower than with DNA-TFO and the thermal stability of the triplex is increased with the salt concentration in EtOH-water solutions. Accordingly, RNA could be considered a potential molecule to form a stable triplex for regulatory purposes in molecular crowding conditions

Citizen science provides a reliable and scalable tool to track disease-carrying mosquitoes

Recent outbreaks of Zika, chikungunya and dengue highlight the importance of better understanding the spread of disease-carrying mosquitoes across multiple spatio-temporal scales. Traditional surveillance tools are limited by jurisdictional boundaries and cost constraints. Here we show how a scalable citizen science system can solve this problem by combining citizen scientists'' observations with expert validation and correcting for sampling effort. Our system provides accurate early warning information about the Asian tiger mosquito (Aedes albopictus) invasion in Spain, well beyond that available from traditional methods, and vital for public health services. It also provides estimates of tiger mosquito risk comparable to those from traditional methods but more directly related to the human-mosquito encounters that are relevant for epidemiological modelling and scalable enough to cover the entire country. These results illustrate how powerful public participation in science can be and suggest citizen science is positioned to revolutionize mosquito-borne disease surveillance worldwide

First detection of Aedes japonicus in Spain: An unexpected finding triggered by citizen science

Background: Aedes japonicus is an invasive vector mosquito from Southeast Asia which has been spreading across central Europe since the year 2000. Unlike the Asian Tiger mosquito (Aedes albopictus) present in Spain since 2004, there has been no record of Ae. japonicus in the country until now. Results: Here, we report the first detection of Ae. japonicus in Spain, at its southernmost location in Europe. This finding was triggered by the citizen science platform Mosquito Alert. In June 2018, a citizen sent a report via the Mosquito Alert app from the municipality of Siero in the Asturias region (NW Spain) containing pictures of a female mosquito compatible with Ae. japonicus. Further information was requested from the participant, who subsequently provided several larvae and adults that could be classified as Ae. japonicus. In July, a field mission confirmed its presence at the original site and in several locations up to 9 km away, suggesting a long-time establishment. The strong media impact in Asturias derived from the discovery raised local participation in the Mosquito Alert project, resulting in further evidence from surrounding areas. Conclusions: Whilst in the laboratory Ae. japonicus is a competent vector for several mosquito-borne pathogens, to date only West Nile virus is a concern based on field evidence. Nonetheless, this virus has yet not been detected in Asturias so the vectorial risk is currently considered low. The opportunity and effectiveness of combining citizen-sourced data to traditional surveillance methods are discussed

At the tip of an iceberg: citizen science and active surveillance collaborating to broaden the known distribution of Aedes japonicus in Spain

Background: Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, however, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert. Methods: The collaboration between Mosquito Alert, the Ministry of Health, local authorities and academic researchers resulted in a multi-source surveillance combining active field sampling with broader temporal and spatial citizen-sourced data, resulting in a more flexible and efficient surveillance strategy. Results: Between 2018 and 2020, the joint efforts of administrative bodies, academic teams and citizen-sourced data led to the discovery of this species in northern regions of Spain such as Cantabria and the Basque Country. This raised the estimated area of occurrence of Ae. japonicus from < 900 km2 in 2018 to > 7000 km2 in 2020. Conclusions: This population cluster is geographically isolated from any other population in Europe, which raises questions about its origin, path of introduction and dispersal means, while also highlighting the need to enhance surveillance systems by closely combining crowd-sourced surveillance with public health and mosquito control agencies’ efforts, from local to continental scales. This multi-actor approach for surveillance (either passive and active) shows high potential efficiency in the surveillance of other invasive mosquito species, and specifically the major vector Aedes aegypti which is already present in some parts of Europe. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s)

α,γ-Peptide nanotube templating of one-dimensional parallel fullerene arrangements

(Figure Presented) The formation and full characterization of single self-assembling α,γ-peptide nanotubes (α,γ-SPNs) is described. The introduction of C60 into cyclic peptides allows the preparation of supramolecular 1D fullerene arrangements induced by peptide nanotube formation under appropriate conditions. © 2009 American Chemical Society.This work was supported by the Spanish Ministry of Education and Science and the ERDF [SAF2007-61015 and Consolider Ingenio 2010 (CSD2007-00006)] and the Xunta de Galicia (GRC2006/ 132, PGIDIT06PXIB209018PR, PGIDIT08CSA047209PR, and R2006/ 124). The work by J.M.V. and J.L.C. was supported by Grants BFU2007- 62382/BMC from the Spanish MEC (J.M.V.) and S-0505/MAT/0283 from the Madrid Regional Government (J.M.V. and J.L.C.). C.R. and R.J.B. thank the Spanish MEC for their FPU Fellowships. We also thank Dr. Carmen Serra (Nanotechnology and Surface Analysis Service at C.A.C.T.I., University of Vigo) for her help with STM. We also thank Dowpharma for their kind gift of ENZA enzymes used in the preparation of D-Boc-γ-Acp-OH.Peer reviewe

Modelling the Dynamics of an Aedes albopictus Population

We present a methodology for modelling population dynamics with formal means of computer science. This allows unambiguous description of systems and application of analysis tools such as simulators and model checkers. In particular, the dynamics of a population of Aedes albopictus (a species of mosquito) and its modelling with the Stochastic Calculus of Looping Sequences (Stochastic CLS) are considered. The use of Stochastic CLS to model population dynamics requires an extension which allows environmental events (such as changes in the temperature and rainfalls) to be taken into account. A simulator for the constructed model is developed via translation into the specification language Maude, and used to compare the dynamics obtained from the model with real data.Comment: In Proceedings AMCA-POP 2010, arXiv:1008.314