Remote in vivo stress assessment of aquatic animals with microencapsulated biomarkers for environmental monitoring

Remote in vivo scanning of physiological parameters is a major trend in the development of new tools for the fields of medicine and animal physiology. For this purpose, a variety of implantable optical micro- and nanosensors have been designed for potential medical applications. At the same time, the important area of environmental sciences has been neglected in the development of techniques for remote physiological measurements. In the field of environmental monitoring and related research, there is a constant demand for new effective and quick techniques for the stress assessment of aquatic animals, and the development of proper methods for remote physiological measurements in vivo may significantly increase the precision and throughput of analyses in this field. In the present study, we apply pH-sensitive microencapsulated biomarkers to remotely monitor the pH of haemolymph in vivo in endemic amphipods from Lake Baikal, and we compare the suitability of this technique for stress assessment with that of common biochemical methods. For the first time, we demonstrate the possibility of remotely detecting a change in a physiological parameter in an aquatic organism under ecologically relevant stressful conditions and show the applicability of techniques using microencapsulated biomarkers for remote physiological measurements in environmental monitoring

Stochastic particle packing with specified granulometry and porosity

This work presents a technique for particle size generation and placement in arbitrary closed domains. Its main application is the simulation of granular media described by disks. Particle size generation is based on the statistical analysis of granulometric curves which are used as empirical cumulative distribution functions to sample from mixtures of uniform distributions. The desired porosity is attained by selecting a certain number of particles, and their placement is performed by a stochastic point process. We present an application analyzing different types of sand and clay, where we model the grain size with the gamma, lognormal, Weibull and hyperbolic distributions. The parameters from the resulting best fit are used to generate samples from the theoretical distribution, which are used for filling a finite-size area with non-overlapping disks deployed by a Simple Sequential Inhibition stochastic point process. Such filled areas are relevant as plausible inputs for assessing Discrete Element Method and similar techniques

Transcriptome-level effects of the model organic pollutant phenanthrene and its solvent acetone in three amphipod species

Polyaromatic hydrocarbons (PAH) are common pollutants of water ecosystems originating from incineration processes and contamination with mineral oil. Water solubility of PAHs is generally low; for toxicity tests with aquatic organisms, they are therefore usually dissolved in organic solvents. Here we examined the effects of a typical model PAH, phenanthrene, and a solvent, acetone, on amphipods as relevant aquatic invertebrate models. Two of these species, Eulimnogammarus verrucosus and Eulimnogammarus cyaneus, are common endemics of the oligotrophic and pristine Lake Baikal, while one, Gammarus lacustris, is widespread throughout the Holarctic and inhabits smaller and more eutrophic water bodies in the Baikal area. Neither solvent nor phenanthrene caused mortality at the applied concentrations, but both substances affected gene expression in all species. Differential gene expression was more profound in the species from Lake Baikal than in the Holarctic species. Moreover, in one of the Baikal species, E. cyaneus, we found that many known components of the cellular xenobiotic detoxification system reacted to the treatments. Finally, we detected a negative relationship between changes in transcript abundances in response to the solvent and phenanthrene. This mixture effect, weaker than the impact by a single mixture component, needs further exploration

Comparison between transcriptomic responses to short-term stress exposures of a common Holarctic and endemic Lake Baikal amphipods.

BACKGROUND: Lake Baikal is one of the oldest freshwater lakes and has constituted a stable environment for millions of years, in stark contrast to small, transient bodies of water in its immediate vicinity. A highly diverse endemic endemic amphipod fauna is found in one, but not the other habitat. We ask here whether differences in stress response can explain the immiscibility barrier between Lake Baikal and non-Baikal faunas. To this end, we conducted exposure experiments to increased temperature and the toxic heavy metal cadmium as stressors. RESULTS: Here we obtained high-quality de novo transcriptome assemblies, covering mutiple conditions, of three amphipod species, and compared their transcriptomic stress responses. Two of these species, Eulimnogammarus verrucosus and E. cyaneus, are endemic to Lake Baikal, while the Holarctic Gammarus lacustris is a potential invader. CONCLUSIONS: Both Baikal species possess intact stress response systems and respond to elevated temperature with relatively similar changes in their expression profiles. G. lacustris reacts less strongly to the same stressors, possibly because its transcriptome is already perturbed by acclimation conditions

Transición y precarización democrática paraguaya: los efectos de la baja calidad institucional y del comportamiento político negativo

ABSTRACT: Objective/context: The work presents a case study of the democratization in Paraguay and debates the hypotheses of an incomplete transition and a stable low-quality democracy. It presents and analyses the transition since 1989, based on the first analytical models of the process, with the development of the institutional structure, the behavior of the main political actors of the process, and citizen behavior. Methodology: The case study undertakes a periodization of the transition in Paraguay, listing the main events and actors. Institutional capacity was examined using the data contributed by the IDD-Lat from 2002 to 2016, whereas citizen behavior was analyzed based on Latin American data from between 1995 and 2016. Conclusions: the low institutional quality and negative citizen behavior towards the regime appear to maintain a relatively stable situation of authoritarian political culture and weak institutions that can be characterized as democratic, but one of low quality that lacks any perspective for change. Originality: Studies on democracy in Paraguay, commonly analyze the development of the institutional structure, institutional capacity or citizen behavior. The proposal of this study is to consider a joining of the perspectives based on the analytical proposals for institutional precarization, together with an attempt at the periodization of the stages of the democratic transition in Paraguay, relating the phases with the process of institutional precarization.RESUMO: Objetivo/contexto: O trabalho realiza um estudo de caso da democratização paraguaia e debate as hipóteses de uma transição incompleta e de uma democracia estável de baixa qualidade. A transição desde 1989 é apresentada e analisada a partir dos principais modelos analíticos do processo com o desenvolvimento da estrutura institucional, do comportamento dos principais atores políticos do processo e do comportamento cidadão. Metodologia: O estudo de caso faz uma periodização da transição paraguaia e lista os principais eventos e atores centrais. Para examinar a capacidade institucional foram utilizados os dados oferecidos pelo IDD-Lat entre 2002 e 2016, enquanto o comportamento cidadão foi analisado a partir dos dados do Latinobarómetro entre 1995 e 2016. Conclusões: Observa-se que a baixa capacidade institucional, juntamente com o comportamento cidadão negativo a respeito do regime, mantêm uma situação relativamente estável de cultura política autoritária e instituições frágeis que pode ser caracterizada como democrática, mas com baixa qualidade e sem perspectiva de mudança. Originalidade: Os estudos sobre a democracia paraguaia comumente analisam o desenvolvimento da estrutura institucional, a capacidade institucional ou o comportamento cidadão. A proposta deste estudo é considerar precisamente a união das perspectivas a partir da proposta analítica da precarização institucional, juntamente com a tentativa de periodização das etapas da transição democrática paraguaia, relacionando as etapas com o processo de precarização institucional.RESUMEN: Objetivo/contexto: El trabajo realiza un estudio de caso de la democratización paraguaya y debate las hipótesis de una transición incompleta y de una democracia estable de baja calidad. Se presenta y analiza la transición desde 1989, a partir de los principales modelos analíticos del proceso, con el desarrollo de la estructura institucional, el comportamiento de los principales actores políticos del proceso y el comportamiento ciudadano. Metodología: El estudio de caso hace una periodización de la transición paraguaya, listando los principales eventos y actores centrales. Para examinar la capacidad institucional fueron utilizados los datos aportados por el IDD-Lat entre 2002 y 2016, mientras que el comportamiento ciudadano fue analizado a partir de los datos del Latinobarómetro entre 1995 y 2016. Conclusiones: Se observa que la baja capacidad institucional, junto con el comportamiento ciudadano negativo hacia el régimen, mantienen una situación relativamente estable de cultura política autoritaria e instituciones débiles que se puede caracterizar como democrática, pero con baja calidad y sin perspectiva de cambio. Originalidad: Los estudios sobre la democracia paraguaya comúnmente analizan el desarrollo de la estructura institucional, la capacidad institucional o el comportamiento ciudadano. La propuesta de este estudio es precisamente considerar la unión de las perspectivas a partir de la propuesta analítica de la precarización institucional, junto con el intento de periodización de las etapas de la transición democrática paraguaya, relacionando las etapas con el proceso de precarización institucional

Genome sequence of the progenitor of the wheat D genome <em>Aegilops tauschii</em>.

Aegilops tauschii is the diploid progenitor of the D genome of hexaploid wheat (Triticum aestivum, genomes AABBDD) and an important genetic resource for wheat. The large size and highly repetitive nature of the Ae. tauschii genome has until now precluded the development of a reference-quality genome sequence. Here we use an array of advanced technologies, including ordered-clone genome sequencing, whole-genome shotgun sequencing, and BioNano optical genome mapping, to generate a reference-quality genome sequence for Ae. tauschii ssp. strangulata accession AL8/78, which is closely related to the wheat D genome. We show that compared to other sequenced plant genomes, including a much larger conifer genome, the Ae. tauschii genome contains unprecedented amounts of very similar repeated sequences. Our genome comparisons reveal that the Ae. tauschii genome has a greater number of dispersed duplicated genes than other sequenced genomes and its chromosomes have been structurally evolving an order of magnitude faster than those of other grass genomes. The decay of colinearity with other grass genomes correlates with recombination rates along chromosomes. We propose that the vast amounts of very similar repeated sequences cause frequent errors in recombination and lead to gene duplications and structural chromosome changes that drive fast genome evolution

Genome sequence of the progenitor of the wheat D genome Aegilops tauschii

International audienceAegilops tauschii is the diploid progenitor of the D genome of hexaploid wheat (Triticum aestivum, genomes AABBDD) and an important genetic resource for wheat. The large size and highly repetitive nature of the Ae. tauschii genome has until now precluded the development of a reference-quality genome sequence. Here we use an array of advanced technologies, including ordered-clone genome sequencing, whole-genome shotgun sequencing, and BioNano optical genome mapping, to generate a reference-quality genome sequence for Ae. tauschii ssp. strangulata accession AL8/78, which is closely related to the wheat D genome. We show that compared to other sequenced plant genomes, including a much larger conifer genome, the Ae. tauschii genome contains unprecedented amounts of very similar repeated sequences. Our genome comparisons reveal that the Ae. tauschii genome has a greater number of dispersed duplicated genes than other sequenced genomes and its chromosomes have been structurally evolving an order of magnitude faster than those of other grass genomes. The decay of colinearity with other grass genomes correlates with recombination rates along chromosomes. We propose that the vast amounts of very similar repeated sequences cause frequent errors in recombination and lead to gene duplications and structural chromosome changes that drive fast genome evolution