Desarrollo de nuevos instrumentos biosensores ambientales para el analisis de herbicidas

Abstract Development of new biosensors is presented, especially sensors screen printed carbon electrodes, gold or printed sensors (screen-printed sensors SPE). These instruments allow for multi parametric analysi

Directed Evolution and In Silico Analysis of Reaction Centre Proteins Reveal Molecular Signatures of Photosynthesis Adaptation to Radiation Pressure

Evolutionary mechanisms adopted by the photosynthetic apparatus to modifications in the Earth's atmosphere on a geological time-scale remain a focus of intense research. The photosynthetic machinery has had to cope with continuously changing environmental conditions and particularly with the complex ionizing radiation emitted by solar flares. The photosynthetic D1 protein, being the site of electron tunneling-mediated charge separation and solar energy transduction, is a hot spot for the generation of radiation-induced radical injuries. We explored the possibility to produce D1 variants tolerant to ionizing radiation in Chlamydomonas reinhardtii and clarified the effect of radiation-induced oxidative damage on the photosynthetic proteins evolution. In vitro directed evolution strategies targeted at the D1 protein were adopted to create libraries of chlamydomonas random mutants, subsequently selected by exposures to radical-generating proton or neutron sources. The common trend observed in the D1 aminoacidic substitutions was the replacement of less polar by more polar amino acids. The applied selection pressure forced replacement of residues more sensitive to oxidative damage with less sensitive ones, suggesting that ionizing radiation may have been one of the driving forces in the evolution of the eukaryotic photosynthetic apparatus. A set of the identified aminoacidic substitutions, close to the secondary plastoquinone binding niche and oxygen evolving complex, were introduced by site-directed mutagenesis in un-transformed strains, and their sensitivity to free radicals attack analyzed. Mutants displayed reduced electron transport efficiency in physiological conditions, and increased photosynthetic performance stability and oxygen evolution capacity in stressful high-light conditions. Finally, comparative in silico analyses of D1 aminoacidic sequences of organisms differently located in the evolution chain, revealed a higher ratio of residues more sensitive to oxidative damage in the eukaryotic/cyanobacterial proteins compared to their bacterial orthologs. These results led us to hypothesize an archaean atmosphere less challenging in terms of ionizing radiation than the present one

Biosensors: new frontiers for the environmental analysis

Los biosensores son bioherramientas muy prometedoras, útiles para la detección rápida, sencilla, económica y confiable de muchas muestras reales. Por sus características intrínsecas, estos dispositivos pueden tener una aplicación en muchos campos diferentes, pero parecen ser especialmente útil para aquellos que requieren análisis repetidos diariamente realiza, tales como campos de la biomedicina, la agricultura y el medio ambiente. Este artículo revisa los biosensores que parecía útil para el análisis del medio ambiente. En particular, el trabajo se centró en los biosensores basados en la fotosíntesis, es decir, los biosensores, cuyos elementos de biorreconocimiento están representados por células enteras o partes de las células, capaces de realizar fotosíntesis. Una visión general sobre este tipo de biosensores, incluidos los métodos para inmovilizar los biomediadores y detectar los contaminantes, se da aquí, junto con los más recientes ejemplos de su aplicación ABSTRACT  Biosensors are very promising biotools useful for the fast, simple, cheap and reliable screening of many real samples. For their intrinsic features, these devices can find application in many different fields, but appear particularly useful for those requiring repeated analyses daily performed, such as biomedical, agricultural and environmental fields. This article reviews the biosensors which appeared useful for environmental analysis. In particular, the work focused on photosynthesis-based biosensors, i.e. biosensors whose biorecognition elements are represented by whole cells, or parts of cells, able to photosynthesize. An overview on this type of biosensors, included the methods to immobilize the biomediators and detect the pollutants, is given here along with the most recent examples of their application.

A Portable Light-Excitation Equipped Bio-Amperometer for Electrogenic Biomaterials to Support the Technical Development of Most Biosensors

A portable multifunction amperometric transducer for monitoring bioactive material has been designed to operate with a wide range of electrogenic biosamples. The system realized is innovative, being designed to be flexible, modular and small, with two independent not-interfering sensing cells equipped with programmable optical excitation, current measurement system and automated flow system. Each of the two cells is provided with screen printed electrodes to measure the generated biocurrent and features different optical sources (LEDs with emission peak at 470nm and 660nm) to activate the photosynthetic electron transfer of various biomediators from plants and/or microrganisms. Target applications belong to the agro-food, pharmaceutical and biomedical fields. To demonstrate the large applicability of the transducer, experimental measurements were conducted with Photosystem II protein and tyrosinase to detect four different pesticides and cathecol, respectively. Further applications in environmental water monitoring and food analysis are envisaged for such biosensors

Biosensing technologies for space applications

Los principales estudios realizados en el espacio hacen referencia a la supervivencia de los astronautas durante los vuelos de larga duración. Uno de los temas más investigados es el ataque continuo de los rayos cósmicos. Con el fin de evaluar el efecto de los rayos cósmicos, dos instrumentos con la inserción de diversos elementos sensores han sido diseñados y construidos: Foto II y Night Vision. El primero es un sensor óptico que voló a bordo de Foton-M2 y Foton-M3, misiones de la Agencia Espacial Europea (ESA), y el segundo es un instrumento que mantiene vivo los diferentes tipos de biomediadores.  El segundo instrumento, llamado Night Vision, mantiene en vida microalgas que contienen manchas oculares y pigmentos maculares de forma similar a la retina humana, con el propósito de predecir el efecto de la radiación espacial en los ojos de los astronautas, y generar resultados aplicables a los programas de nutrición futuras en el espacio ABSTRACT The main studies performed in space deal with the survival of the astronauts during flights of long duration. One of the most investigated issues is the continuous attack of the cosmic ray. In order to assess the effect of the cosmic ray, two instruments hosting various sensing elements have been designed and constructed: Photo II and Night Vision. The first is an optical sensor which flew on board Foton-M2 and Foton-M3 missions of the European Space Agency; the second is an instrument that maintains alive different types of biomediators. The second instrument, called Night Vision, maintained alive algal microorganisms containing eyespots and macular pigment similar to human retina, with the purpose to predict the effect of space radiation on the astronauts‟ eye, in order to obtain results applicable to future nutrition programs in space

Ovotransferrin expression and release by chicken cell lines infected with Marek's disease virus

Mammals posses both serum transferrin and lactoferrin, whose functions are taken over in birds by ovotransferrin, displaying both iron transport and antibacterial activities, Ovotransferrin also exerts antiviral activity towards Marek's disease virus, an avian member of the herpes famiJy of viruses, This virus infects Iymphoid organs and induces the transcription of ovotransferrin in infected chicken embryo fibroblasts. However, it has not yet been established whether ovotransferrin gene transcription is Iinked to the release or the protein outside the cells or whether ovotransferrin expression and release also occurs in chicken lymphoblastoid cclls in which the Marek 's disease virai genome is integrated. Our results indicate that both serum and egg-white isoforms of ovotransferrin are expressed and released in the supernatants of chicken embryo fibroblast and Iymphoblastoid cells in tbe absence of infection. ViraI infection of chicken embryo fibroblasts caused a slight increase of ovotransferrin release, whereas viraJ reinfection of lyrnphoblastoid cells caused a rernarkable ovotransferrin release in a virus coucentratìon-dependent manner. These findings suggest rhat ovotransferrin release in vivo may play a cruciaJ role in protecting the whole organism from virai infection spreading, and support the hypothesis that the antiviral activity of ovotransferrin is an important part of the innate immune response in birds, resembling the anriviral activity of lactoferrin in marnmals

Investigation of Photosystem II Functional Size in Higher Plants under Physiological and Stress Conditions Using Radiation Target Analysis and Sucrose Gradient Ultracentrifugation

The photosystem II (PSII) reaction centre is the critical supramolecular pigment–protein complex in the chloroplast which catalyses the light-induced transfer of electrons from water to plastoquinone. Structural studies have demonstrated the existence of an oligomeric PSII. We carried out radiation inactivation target analysis (RTA), together with sucrose gradient ultracentrifugation (SGU) of PSII, to study the functional size of PSII in diverse plant species under physiological and stress conditions. Two PSII populations, made of dimeric and monomeric core particles, were revealed in Pisum sativum, Spinacea oleracea, Phaseulus vulgaris, Medicago sativa, Zea mais and Triticum durum. However, this core pattern was not ubiquitous in the higher plants since we found one monomeric core population in Vicia faba and a dimeric core in the Triticum durum yellow-green strain, respectively. The PSII functional sizes measured in the plant seedlings in vivo, as a decay of the maximum quantum yield of PSII for primary photochemistry, were in the range of 75–101 ± 18 kDa, 2 to 3 times lower than those determined in vitro. Two abiotic stresses, heat and drought, imposed individually on Pisum sativum, increased the content of the dimeric core in SGU and the minimum functional size determined by RTA in vivo. These data suggest that PSII can also function as a monomer in vivo, while under heat and drought stress conditions, the dimeric PSII structure is predominant

Photoautotrophs–Bacteria Co-Cultures: Advances, Challenges and Applications

Photosynthetic microorganisms are among the fundamental living organisms exploited for millennia in many industrial applications, including the food chain, thanks to their adaptable behavior and intrinsic proprieties. The great multipotency of these photoautotroph microorganisms has been described through their attitude to become biofarm for the production of value-added compounds to develop functional foods and personalized drugs. Furthermore, such biological systems demonstrated their potential for green energy production (e.g., biofuel and green nanomaterials). In particular, the exploitation of photoautotrophs represents a concrete biorefinery system toward sustainability, currently a highly sought-after concept at the industrial level and for the environmental protection. However, technical and economic issues have been highlighted in the literature, and in particular, challenges and limitations have been identified. In this context, a new perspective has been recently considered to offer solutions and advances for the biomanufacturing of photosynthetic materials: the co-culture of photoautotrophs and bacteria. The rational of this review is to describe the recently released information regarding this microbial consortium, analyzing the critical issues, the strengths and the next challenges to be faced for the intentions attainment