Analysis of two genomes from the mitochondrion-like organelle of the intestinal parasite Blastocystis: complete sequences, gene content, and genome organization.

Acquisition of mitochondria by the ancestor of all living eukaryotes represented a crucial milestone in the evolution of the eukaryotic cell. Nevertheless, a number of anaerobic unicellular eukaryotes have secondarily discarded certain mitochondrial features, leading to modified organelles such as hydrogenosomes and mitosomes via degenerative evolution. These mitochondrion-derived organelles have lost many of the typical characteristics of aerobic mitochondria, including certain metabolic pathways, morphological traits, and, in most cases, the organellar genome. So far, the evolutionary pathway leading from aerobic mitochondria to anaerobic degenerate organelles has remained unclear due to the lack of examples representing intermediate stages. The human parasitic stramenopile Blastocystis is a rare example of an anaerobic eukaryote with organelles that have retained some mitochondrial characteristics, including a genome, whereas they lack others, such as cytochromes. Here we report the sequence and comparative analysis of the organellar genome from two different Blastocystis isolates as well as a comparison to other genomes from stramenopile mitochondria. Analysis of the characteristics displayed by the unique Blastocystis organelle genome gives us an insight into the initial evolutionary steps that may have led from mitochondria to hydrogenosomes and mitosomes

Comparative analysis of two genomic regions among four strains of Buchnera aphidicola, primary endosymbiont of aphids.

Preliminary analysis of two selected genomic regions of Buchnera aphidicola BCc, the primary endosymbiont of the cedar aphid Cinara cedri, has revealed a number of interesting features when compared with the corresponding homologous regions of the three B. aphidicola genomes previously sequenced, that are associated with different aphid species. Both regions exhibit a significant reduction in length and gene number in B. aphidicola BCc, as it could be expected since it possess the smallest bacterial genome. However, the observed genome reduction is not even in both regions, as it appears to be dependent on the nature of their gene content. The region fpr-trxA, that contains mainly metabolic genes, has lost almost half of its genes (45.6%) and has reduced 52.9% its length. The reductive process in the region rrl-aroK, that contains mainly ribosomal protein genes, is less dramatic, since it has lost 9.3% of genes and has reduced 15.5% of its length. Length reduction is mainly due to the loss of protein-coding genes, not to the shortening of ORFs or intergenic regions. In both regions, G+C content is about 4% lower in BCc than in the other B. aphidicola strains. However, when only conserved genes and intergenic regions of the four B. aphidicola strains are compared, the G+C reduction is higher in the fpr-trxA region

Structural and Technological Features of the Emerging Occupational Hazard in Manufacturing Environments

En los entornos de fabricación pueden existir riesgos denominados por la Agencia Europea para la Seguridad y Salud en el Trabajo como riesgos nuevos y emergentes. Con el presente trabajo se han analizado las características estructurales y tecnológicas de dichos riesgos aplicando recientes modelos. De los resultados obtenidos se desprende como principal conclusión que las descripciones de estos riesgos no permiten comprender sus cualidades nuevas y emergentes. No obstante, ha sido posible identificar entre dichos riesgos un conjunto de aspectos tecnológicos con el que establecer un punto de partida en materia de riesgos nuevos y emergentes en entornos de fabricación.In manufacturing environments there can be risks described by the European Agency for Safety and Health at Work as “new and emerging risks”. In this paper, structural and technological characteristics of these risks have been analyzed by applying new models. The main apparent conclusion from the results is that from the descriptions of those risks it is not possible to understand its new and emerging qualities. However, it has been possible to identify among those risks a set of technological aspects with which a starting point in the field of new and emerging risks in manufacturing environments can be established

Analysis and Modeling of New and Emerging Occupational Risks in the Context of Advanced Manufacturing Processes

Besides traditional occupational risks, advanced manufacturing processes (AMP) can generate other risks described by the European Agency for Safety and Health at Work (EU-OSHA) as “new and emerging risks” (NER) to occupational safety and health. Several studies have been carried out by the EU-OSHA in order to identify all these risks. However, the direct use of this set of NER in identification procedures of occupational risks, generally applied in labour processes and particularly in AMP, may result in the identification of traditional occupational risks rather than NER, mainly because they have been defined without following a risk reference model. To solve this problem a risk model has been developed that improves and complements the NER definition of EU-OSHA, from which a second model has been developed to analyze the structure of the considered set of NER. It is observed that with the results obtained, the current descriptions of these NER do not explain their quality of “new and “emerging”

Analysis of Open Resources from INSHT for Application to University Teaching of Industrial Safety Technology

This work is developed in the teaching context of the subject “Technological Aspects of Safety” (ATS) as part of the University Master's Degree in Occupational Safety and Health (OSH) of the National University of Distance Education (UNED). A classification of Industrial Safety Technologies, grouped in ATS, has been developed that links basic rules applicable to the technical guides (TG) and Technical Notes Prevention (NTP) of the National Institute of Safety and Health at Work (INSHT). The TG are essential tools for the technical interpretation of associated regulations, as their updates are generally adequate, not so for the NTP, especially considering that 54% of those analyzed predate 1997 (beginning of basic regulatory development). However, the characteristics of the classification aids the design of teaching activities, focused on the analysis and knowledge of the industrial safety technologies

A Linear Molecule with Two Large Inverted Repeats: The Mitochondrial Genome of the Stramenopile Proteromonas lacertae

Mitochondrial evolution has given rise to a complex array of organelles, ranging from classical aerobic mitochondria to mitochondrial remnants known as hydrogenosomes and mitosomes. The latter are found in anaerobic eukaryotes, and these highly derived organelles often retain only scant evidence of their mitochondrial origins. Intermediate evolutionary stages have also been reported as facultatively or even strictly anaerobic mitochondria, and hydrogenosomes that still retain some mitochondrial features. However, the diversity among these organelles with transitional features remains rather unclear and barely studied. Here, we report the sequence, structure, and gene content of the mitochondrial DNA of the anaerobic stramenopile Proteromonas lacertae. It has a linear genome with a unique central region flanked by two identical large inverted repeats containing numerous genes and “telomeres” with short inverted repeats. Comparison with the organelle genome of the strictly anaerobic human parasite Blastocystis reveals that, despite the close similarity of the sequences, features such as the genome structure display striking differences. It remains unclear whether the virtually identical gene repertoires are the result of convergence or descent

New Insights on the Evolutionary History of Aphids and Their Primary Endosymbiont Buchnera aphidicola

Since the establishment of the symbiosis between the ancestor of modern aphids and their primary endosymbiont, Buchnera aphidicola, insects and bacteria have coevolved. Due to this parallel evolution, the analysis of bacterial genomic features constitutes a useful tool to understand their evolutionary history. Here we report, based on data from B. aphidicola, the molecular evolutionary analysis, the phylogenetic relationships among lineages and a comparison of sequence evolutionary rates of symbionts of four aphid species from three subfamilies. Our results support previous hypotheses of divergence of B. aphidicola and their host lineages during the early Cretaceous and indicate a closer relationship between subfamilies Eriosomatinae and Lachninae than with the Aphidinae. They also reveal a general evolutionary pattern among strains at the functional level. We also point out the effect of lifecycle and generation time as a possible explanation for the accelerated rate in B. aphidicola from the Lachninae

Analysis of the assessment process for radon exposure occurring from natural sources in the occupational environment

La exposición al radón (Rn-222) constituye una preocupación grave para las agencias internacionales de salud pública, por la dimensión de la población potencialmente expuesta y su principal característica como cancerígeno. Dentro del marco reglamentario de aplicación, destaca la Directiva 2013/59/EURATOM. En dicha directiva se prevé la reducción de los niveles máximos de concentración de radón en espacios cerrados, tanto en viviendas como en los lugares de trabajo así como la redacción de un Plan Nacional preventivo. El objetivo principal de presente trabajo es desarrollar un enfoque inicial con el que llevar a cabo una evaluación de riesgos por exposición laboral al radón mediante el uso de los niveles de referencia establecidos en la Directiva 2013/59/EURATOM y en la cartografía del potencial de radón en España. Como principal resultado, se ha propuesto un enfoque cualitativo para pre-evaluar el riesgo laboral por exposición a radón mediante un check-list, en base a las condiciones de trabajo y las condiciones estructurales asociadas de edificaciones o instalaciones. Dicho enfoque debe considerarse una primera fase para la aproximación al riesgo por exposición laboral al radón. En el futuro, dicha propuesta podrá ampliarse, calibrarse y validarse con objeto de obtener una herramienta con suficiente fiabilidad científico-tecnológica.Radon (Rn-222) is a serious concern for international public health agencies, due to the population size that could be exposed to this gas, and its main property as a carcinogen. Directive 2013/59/EURATOM stands out. This directive foresees the reduction of the maximum levels of radon concentration in enclosed spaces, both in homes and in workplaces and the drafting of a National Preventive Plan. The main objective of this work is to develop an initial approach to carry out a risk assessment for occupational exposure to radon by using the reference levels established in Directive 2013/59/EURATOM as well as the information contained in the mapping of radon potential in Spain. As a main result, a qualitative approach has been proposed to pre-assess occupational risk due to exposure to radon by means of a check-list, that takes into account the working conditions and the structural conditions of the buildings or facilities where the workday takes place. The proposed qualitative approach should be considered as a first phase for the approach to occupational exposure to radon in buildings or facilities. Through future work, this proposal can be extended, calibrated and validated in order to develop a tool with sufficient scientific and technical reliability

Coexistence of Wolbachia with Buchnera aphidicola and a secondary symbiont in the aphid Cinara cedri.

Intracellular symbiosis is very common in the insect world. For the aphid Cinara cedri, we have identified by electron microscopy three symbiotic bacteria that can be characterized by their different sizes, morphologies, and electrodensities. PCR amplification and sequencing of the 16S ribosomal DNA (rDNA) genes showed that, in addition to harboring Buchnera aphidicola, the primary endosymbiont of aphids, C. cedri harbors a secondary symbiont (S symbiont) that was previously found to be associated with aphids (PASS, or R type) and an alpha-proteobacterium that belongs to the Wolbachia genus. Using in situ hybridization with specific bacterial probes designed for symbiont 16S rDNA sequences, we have shown that Wolbachia was represented by only a few minute bacteria surrounding the S symbionts. Moreover, the observed B. aphidicola and the S symbionts had similar sizes and were housed in separate specific bacterial cells, the bacteriocytes. Interestingly, in contrast to the case for all aphids examined thus far, the S symbionts were shown to occupy a similarly sized or even larger bacteriocyte space than B. aphidicola. These findings, along with the facts that C. cedri harbors the B. aphidicola strain with the smallest bacterial genome and that the S symbionts infect all Cinara spp. analyzed so far, suggest the possibility of bacterial replacement in these species

Analysis of Metrological Requirements in Occupational Health and Safety Regulations Related to the Emerging Risk of Exposure to Vibrations

In occupational exposure to vibration, the risk assessment process is defined through a regulatory framework that presents some relevant metrological problems. This framework considers methods based on estimation and on measurements. Estimation methods could employ existing information that is provided for each manufacturer to each individual tool or application to carry out such estimation. The use of estimation methods has some problems, such as substantial uncertainty. When using measurement methods, some metrological aspects are not fully defined. Therefore, a new and emerging risk appears due to certain methodologic limitations. Consequently, the variation between the estimated and the actual values could overestimate the level of occupational exposure to vibrations. Thus, with this paper, a critical analysis of this emerging metrological problem is provided. For this, a critical analysis of the metrological requirements regarding European standards is developed. To this end, the estimation method and measure method are investigated, considering, in both cases, the main factors related to uncertainty, reliability, and traceability. With this structure, a set of metrological limitations have been identified, thus pointing towards future lines of research that allow the improvement of the process of assessing the level of occupational exposure to vibrations.This work was funded by the Spanish Ministry of Economy and Competitiveness, with the title: “Analysis and Assessment of technological requirements for the design of a New Emerging Risks standardized management SYStem (A2NERSYS)” with reference DPI2016-79824-R